dos_jan_2017

Editor-in-chief Volume 22 No. 4
January-February
M. Vanathi 2017

Section Editors Editorial Capsule 47 IOFB via an Impromptu
Cataract & Refractive Retina & Uvea
7 Individual Commitment to Approach
Umang Mathur Pradeep Venketesh
Saurabh Sawhney Parijat Chandra Group Effort 49 Multifocal Choroiditis-

Sanjiv Mohan Manisha Aggarwal A Case Report
S. Khokhar Shahana Majumdhar
Featuring Sections 53 Spectacle Prescription in
Cornea & Oular Surface Rohan Chawla Children: Understanding
Uma Sridhar Ravi Bypareddy
Deepa Gupta Ophthalmoplasty & Retina Prevalent Practice Patterns
9 Myopic Traction Maculopathy: 57 Management of Peripheral
Umang Mathur Ocular Oncology Our Experience
Ramendra Bakshi Neelam Pushker Corneal Diseases
Manisha Acharya Maya Hada 63 Cataract in the Silicone Oil

Noopur Gupta Sangeeta Abrol Researh Methodology ϐ‹ŽŽ‡† ›‡
Glaucoma Rachna Meel
13 Clinical Research - Back to Basics Diagnostics Discussion
Dewang Angmo Squint & 67 Importance of Microbiological
Reena Sharma Neuro-ophthalmology Understanding Modern
Sunita Dubey Digvijay Singh …‹‡–‹ϐ‹… ‡–Š‘†•ǣ ƒ ‹’Ž‹ϐ‹‡† ‘” —’ ‹ †‡–‹ϐ‹…ƒ–‹‘ ‘ˆ
Viney Gupta Zia Chaudhuri Atypical Organisms and their
Kanak Tyagi Suma Ganesh View
Delhi Advisory Board
Y.R. Sharma Mahipal Sachdev Refractive Surgery Management in Corneal Ulcers
Atul Kumar Radhika Tandon
P.V. Chadha Jolly Rohtagi 17 Post Lasik Ectasia: Quick Picks
Recent Concepts 71 Papilloedema
Noshir M. Shroff J.C. Das
Rajendra Khanna B.P. Gulliani 21 Contoura Vision Topo Guided

Vimla Menon Ritu Arora Lasik on the Wavelight Platform
H.K. Yaduvanshi Kamlesh DOS TIMES Quiz
73 QUIZ - Episode 4
Anita Panda G.K. Das Cataract
Pradeep Sharma Lalit Verma 25 Fluids in Eye Surgery
Ramanjit Sihota Tanuj Dada DOS Crossword
75 DOS CROSSWORD-
Harish Gandhi Abhishek Dagar Ocular Surface Episode 4
Anup Goswami Sarita Beri 29 Mucous Membrane Grafting –

Rajpal P.K. Sahu the Rescuer! News Watch
Mandeep Bajaj Kamlesh
Ocular Microbiology 77 DOS Clinical Monthly
B. Ghosh Taru Dewan 35 Ocular Infections: Meet–V
Rajiv Garg H.S. Sethi Microbiological Perspective
55,65,78 DOS Announcements
R.B. Jain H.K. Tewari 79 DOS Membership Form
National Advisory Board
R.D. Ravindran Barun Nayak Monthly Meeting Korner 81 Joint iDOS-COSL 2016 Meeting
Debashish Bhattacharya Venketesh Prajna
R. Revathi S. Natarajan 43 Asymmetric Ocular
Yogesh Shah Amod Gupta
Arup Charaborti Jagat Ram Hypertension in a Young Adult -
Anita Raghavan Amar Agarwal
Chandna Chakraborti Mangat Ram Dogra A Diagnostic Conundrum
Sushmita Shah D. Ramamurthy
Sushmita Kaushik T.P. Lahane DOS Membership fee Revision
Pravin Vadavalli Samar Basak Please note that DOS Membership Fee for new
Somshiela Murthy Cyrus Mehta
Sri Ganesh Mahesh Shanmugam members has been revised to Rs. 5,600/-
M.S. Ravindra J. Biswas with effect from September 10, 2016.
Rohit Shetty Srinivas Rao
Mallika Goyal Nikhil Gokale www. dos-times.org 3
Partha Biswas Santosh Honavar
Nirmal Frederick Arulmozhi Varman
Abhay Vasavada Mohan Rajan
Mukesh Taneja Rakhi Kusumesh
Shalini Mohan Gopal S. Pillai
Ragini Parekh Subendu Boral
Tejas Shah Gunjan Prakash
Sujith Vengayil Pravin More
M. Kumaran Sajjad Ahmed Shiekh
Punith Kumar Santhan Gopal
Elankumaran

DOS Correspondents
Anita Ganger Dewang Angmo
Rebika Dhiman Shikha Yadav
Manish Mahabir Archita Singh
Raghav Ravani Meenakshi Wadwani

Divya Singh Mayank Bansal
Mukesh Patil Saranya

DOS TIMES
Editorial Assistance & Layout: SUNIL KUMAR

Printer: New Pusphak Printers
Cover Design: Aman Dua

DOS Times will hitherto be published once every two months by Dr.
M. Vanathi, on behalf of Delhi Ophthalmological Society, DOS Secretariat,
Dr. R.P. Centre, AIIMS, New Delhi. All solicited & unsolicited manuscripts
submitted to DOS TIMES are subject to editorial review before acceptance.
DOS TIMES is not responsible for the statements made by the contributors.
All advertising material is expected to conform to ethical standards and
acceptance does not imply endorsement by DOS TIMES. ISSN 0972-0723

EDITORIAL CAPSULE

NDIVIDUAL OMMITMENT TO ROUP FFORT

“Individual Commitment to a group effort – that is what makes a team work, a company work, a society
work, a civilization work.”

– Vince Lombardi

Dear DOS Members,

The new year opens with usual hustle and bustle of all the usual
happenings as always. One more year passes as we plan towards more
academics and activities of our society. DOS is successfully treading into
the second year of this executive as a much-reputed state ophthalmic
society. It has set high standards and lifted ophthalmology academics to
greater heights than ever before.

We are indeed happy to bring to the kind notice of our members
the resounding success of our winterDOS 2016 meeting amidst the
demonetization turmoil. The Joint iDOS – COSL 2016 meeting in Colombo,
Srilanka also took off with a sparkling start and ended on a high note
of promise of academic collaboration and friendship between the two
ophthalmic societies.

—” ’”‘‰”‡•• –‘™ƒ”†• –Š‡ ϐ‹ƒŽ ƒ…ƒ†‡‹… ‡‡–‹‰ ‘ˆ –Š‹• ‡š‡…—–‹˜‡ ‹•

heartening with the planning for the forthcoming 68th annual conference

of DOS – DOSCON 2017: Ophthalmic SPECTRUM going on in full swing. Dr. M.Vanathi
We look forward to another fabulous closing conference to draw the

curtains on this executive. May we call upon all our members and friend

of the ophthalmic world to step forward to contribute high caliber ophthalmic literature and experiences for

this meeting.

The AIOS election scenario is electrifying as ever; never the less, the DOS election scenario is also set to
follow suit soon after. Let us prevail upon our ophthalmic fraternity – both contestants and voters to embrace
the values and principles in all that is required for the contesting portals and the ballot power.

In DOS, we remain committed to make our society work amidst all highs and lows with our individual
commitment to team effort. We request you to join in to support and applaud all our efforts, for in your power
of support, lies our strength to perform and excel.

Looking forward to greeting you all for DOSCON 2017

With best regards

Dr. M.Vanathi MD
DOS General Secretary
& Prof of Ophthalmology
Cornea & Ocular Surface, Cataract & Refractive Services
Dr R P Centre for Ophthalmic Sciences
All India Institute of Medical Sciences
New Delhi 110029
[email protected]

www. dos-times.org 7

RETINA

MYOPIC TRACTION MACULOPATHY: OUR EXPERIENCE

Raghav Ravani, Prateek Kakar, Karthikeya R, Atul Kumar

Myopia is one of the leading causes of poor detachment (vitreoschisis), presence of epiretinal membranes
vision in the world and is seen frequently and inherent rigidity of the internal limiting membrane15.
in the outpatient settings in our country. These factors result in a centripetal traction, the effect of which
The North Indian Myopia Study (2015) is greatly enhanced in presence of centrifugal force exerted by
estimated the prevalence of myopia in progressive stretching and staphyloma in highly myopic eyes.

urban school children in New Delhi to be Traction from the retinal vessels is also thought to

13.1%1Ǥ ‘–Š‡” •–—†› ‹ …‡–”ƒŽ †‹ƒ †‡ϐ‹‡† Š‹‰Š ›‘’‹ƒ predispose to myopic foveoschisis. These can be observed on

ƒ• Šƒ˜‹‰ ƒ ƒš‹ƒŽ Ž‡‰–Š ‘ˆ ‰”‡ƒ–‡” –Šƒ ʹ͸ǤͷԜ ƒ† ˆ‘—† OCT images as retinal vascular microfolds on the retinal surface

a prevalence rate of 0.53% (25/4698 participants)2. The (Figure 1)16.

prevalence of pathologic myopia varies in different geographic Highly myopic eyes develop vitreous liquefaction at a

regions, with highest prevalence in Asian population3,4. There younger age and may have larger precortical vitreous pockets

‹• ƒ •‹‰‹ϐ‹…ƒ– ”‹•‡ ‹ –Š‡ —„‡” ‘ˆ ’ƒ–‹‡–• ™‹–Š ’ƒ–Š‘Ž‘‰‹…ƒŽ than normal eyes resulting in a high incidence of residual

myopia presenting in retina clinic of Dr. Rajendra Prasad Centre vitreous cortex on the retina after complete posterior vitreous

for ophthalmic sciences, AIIMS, New Delhi. detachment (PVD) in these eyes17. This could result from

The term myopic traction splitting of the lamellar vitreous

maculopathy was proposed Š‡”‡ ‹• ƒ •‹‰‹ϐ‹…ƒ– ”‹•‡ ‹ –Š‡ —„‡” cortex (vitreoschisis) with the
by Panozzo and Mercanti to outermost layer of the cortex
‡…‘’ƒ•• ˜ƒ”‹‘—• ϐ‹†‹‰• ‘ of patients with pathological myopia remaining on the retina11,18,19.

optical coherence tomography presenting in retina clinic of Dr. Rajendra Contraction of this premacular
(OCT) in highly myopic eyes, vitreous generates anterior
all of them having traction in Prasad Centre for Ophthalmic Sciences, traction on the fovea and can

common. This includes traction AIIMS, New Delhi lead to foveal retinal detachment

induced by vitreomacular and foveal retinoschisis20-22.

adhesions (vitreomacular The impact of myopic

traction [VMT]) and/or epiretinal membrane (ERM) in retinopathy on visual impairment is often bilateral and

combination with degenerative fundus changes which may irreversible, affecting individuals during their productive

lead to macular damage in the form of foveoschisis, lamellar years. Myopic foveoschisis is often asymptomatic initially but

macular holes, or shallow detachments5-7. progresses slowly and variably, leading to loss of central vision

Incidence of myopic foveoschisis is about 9% of high from foveal detachment or macular hole formation.

myopes with posterior staphyloma8. Myopic foveoschisis Patients can present with reduced vision or central

may remain anatomically and functionally stable for quite metamorphopsia or may remain asymptomatic for a long

long duration, with case reports of spontaneous resolution time23,24. A retrospective study of myopic foveoschisis showed

over time9-11. With the use of OCT, it has been estimated that worsening of visual acuity in 69% and stable vision in 31% over

the prevalence of MTM in highly myopic eyes with posterior a mean follow-up of 31.2 months25.

staphyloma ranged from 9% to as high as 34%7,8,10. Management: In symptomatic patients with vision loss

or metamorphopsia, pars plana vitrectomy (PPV), internal

PATHOPHYSIOLOGY limiting membrane (ILM) peeling and gas tamponade have

The mechanism of development of foveoschisis is been shown to result in the resolution of MTM with visual
postulated to be as a result of proliferation and migration of glial improvement with different success rates20,24,26,27. ILM peeling
astrocytes through the paravascular lamellar holes resulting is commonly described in idiopathic and myopic macular holes
in production of collagen. This facilitates the contractile and for improving macular hole closure rates28-30.
proliferative response of the ILM leading to the foveoschisis12.
Three independent factors associated with foveoschisis and Hirakata et al compared vitrectomy with and without
ILM peeling in 71 eyes with myopic traction maculopathy and

foveal detachment without macular hole in highly myopic

eyes are macular chorioretinal atrophy, axial length, and

vitreoschisis at the vitreoretinal interface13.

Myopic foveoschisis almost always occurs within the

posterior staphyloma due to a gradual stretching or splitting

of the retina between the non-compliant inner retina and

–Š‡ ”‡Žƒ–‹˜‡Ž› ϐŽ‡š‹„Ž‡ ‘—–‡” ”‡–‹ƒ14. Various factors leading

–‘ Ž‹‹–ƒ–‹‘ ‘ˆ ‹‡” ”‡–‹ƒŽ ϐŽ‡š‹„‹Ž‹–› ‹…Ž—†‡ ƒ†Š‡”‡…‡

of vitreous cortex to the retina after posterior vitreous Figure 1: Radial SD-OCT scan showing traction over vascular arcade
with extensive myopic foveoschisis.

www. dos-times.org 9

RETINA

concluded that there was a SURGICAL PLAN

„‡––‡” ϐ‹ƒŽ ™‹–Š ”‡†—…‡† The patients with MTM

rates of recurrence of tractional underwent Pars Plana Vitrectomy

macular detachment in the including Triamcinolone assisted

eyes undergoing ILM peeling PVD induction done in all cases

as compared with the eyes gently using the vitrecomy

undergoing vitrectomy alone31. cutter (single surgeon AK).

Scleral buckling with Triamcinolone assisted careful

macular plombe has also been peeling of the schitic hyaloid was

described for eyes with myopic done in all the eyes subsequently.

macular retinoschisis and Figure 2: A representative image of iOCT guided fovea sparing - ILM BBG stained ILM peeling was
retinal detachment without peeling. The white arrows depict the margins of spared central ILM then carried out in all cases. We
macular hole. However, a UGGP CU DTKIJV TGƀGEVKXKV[ QP K1%6
imaged the operating eye with
high rate of recurrence of
intra-operative OCT (iOCT), and
foveoschisis and development
iOCT guided fovea sparing ILM
of full-thickness macular hole
peeling was done (Figure 2). This
has been reported with this
was followed by FAE and 25%
technique32,33.
SF6 tamponade.
Shimada et al described Figure 3a: Representative SS - OCT images at baseline of a patient with
foveal sparing internal limiting myopic foveoschisis. The iOCT done in our study

membrane peeling for myopic eyes helped in intraoperative

traction maculopathy. They real time visualization of

showed that none of the eyes vitreoretinal interface, the foveal

that underwent fovea-sparing architecture including cystic

ILM peeling developed a changes, presence of an ERM and

full thickness macular hole ILM curling following successful
postoperatively. In addition, Figure 3b: SS- OCT image at 6 months post-operative showing good
–Š‡ ™ƒ• •‹‰‹ϐ‹…ƒ–Ž› anatomical success with complete resolution of myopic foveoschisis. peeling. Areas of retinal thinning
ƒ– ˆ‘˜‡ƒ ™‡”‡ ‹†‡–‹ϐ‹‡† ƒ†
better than the preoperative •—”‰‹…ƒŽ ’Žƒ ™ƒ• ‘†‹ϐ‹‡†

BCVA in the fovea-sparing ILM peeled accordingly. In addition, it served
group34.
or decreased vision requiring surgical –‘ †‡ϐ‹‡ ƒ ‡† ’‘‹– ‘ˆ •—”‰‡”› ™‹–Š
PPV without ILM peeling has also management. The rest 37% (11/30) visualization of resolution of traction
been described in some studies35,36. patients have been on conservative upon completion of vitrectomy and
These studies postulate that complete management with regular follow-up. membrane peeling.
ILM peeling may destabilize Muller cells The patients’ age ranged from 52 to 62
…ƒ—•‹‰ †‡”‘‘ϐ‹‰ ‘ˆ …›•–‹… •’ƒ…‡• ƒ† years, with a female preponderance. Thus, use of intraoperative OCT can
formation of macular holes at a later The pre-operative best corrected visual facilitate complete removal of traction and
stage. acuity in patients undergoing surgery help ensure that no residual membrane
ranged from 0.77 to 1.77 log MAR units. leading to continued traction is remaining
or even view an iatrogenic macular hole

OUR EXPERIENCE The average refractive error (spherical which can then be managed. The added
equivalent) of patients was about -16.5 advantage of selective center sparing ILM
‡…‡–Ž›ǡ –Š‡”‡ Šƒ• „‡‡ ƒ •‹‰‹ϐ‹…ƒ– diopters. Foveoschisis was the most peeling using intraoperative OCT can help
rise in number of patients with common optical coherence tomography spare the ILM in areas of cystic changes
pathological myopia, presenting to our (OCT) characteristic seen in all patients. and thus avoid surgical complications like
retina clinics. With increased awareness –Š‡” ϐ‹†‹‰• ‹…Ž—†‡† ’”‡•‡…‡ †‡”‘‘ϐ‹‰ ‘ˆ …›•– Ž‡ƒ†‹‰ –‘ ƒ…—Žƒ” Š‘Ž‡
and availability of high resolution SD- of an epiretinal membrane (ERM), formation, while ensuring that all traction
OCT and also swept source OCT, a taut posterior hyaloid, neurosensory is released.
•‹‰‹ϐ‹…ƒ– —„‡” ‘ˆ ’ƒ–‹‡–• Šƒ˜‡ „‡‡ detachment and lamellar hole. Posterior All patients showed good anatomical

diagnosed with MTM. In the last 1 year, staphyloma was present in all these and functional success as suggested
about 30 patients have been diagnosed patients with an average axial length of „› •‹‰‹ϐ‹…ƒ– ‹’”‘˜‡‡– ‹
with MTM of which about 63% (19/30) 29.24±1.61 mm. and reduction in CMT on OCT (Figure

with complains of metamorphopsia 3a & Figure 3b). None of these eyes,

Dr R.P. Centre for Ophthalmic Sciences,All India Institute of Medical Sciences, New Delhi, India

Dr. Raghav Ravani MD Dr. Prateek Kakar MD Dr. Karthikeya R. MD Prof.Atul Kumar MD, FAMS

10 DOS TIMES - JANUARY- FEBRUARY 2017

RETINA

while manipulating 13. Wu PC, Chen YJ, Chen YH, et al. Factors associated
with foveoschisis and foveal detachment without
in the macular region macular hole in high myopia. Eye (Lond) 2009;
23:356–61.
can also increase the
14. Ikuno Y. Pathogenesis and treatment of myopic
risk of complications. foveoschisis. Nippon Ganka Gakkai Zasshi
2006;110:855–63.
Aberrations produced
15. Bando H, Ikuno Y, Choi JS, et al. Ultrastructure
at the edges of the optic of internal limiting membrane in myopic
foveoschisis. Am J Ophthalmol 2005;139:197–9.
are demonstrated in
16. Ikuno Y, Ohji M. High Myopia and the Vitreoretinal
(Figure 4). Complications. Retina 5th Ed, China: Saunders,
2011;1914.
Figure 4: )JQUV KOCIGU XKGYGF VJTQWIJ VJG %JCNCOs ƀCV NGPU
RNCPQ Thus, myopic
17. Morita H Funata M Tokoro T. A clinical study of the
concave) during tricot assisted removal of vitreoschisis and ILM peeling foveoschisis is development of posterior vitreous detachment in

HQXGC URCTKPI QXGT OCEWNC high myopia. Retina .1995;15:117–124.
an increasingly
18. Sayanagi K, Ikuno Y, Tano Y. Different fundus
diagnosed and ƒ—–‘ϐŽ—‘”‡•…‡…‡ ’ƒ––‡”• ‘ˆ ”‡–‹‘•…Š‹•‹• ƒ†
macular hole retinal detachment in high myopia.
undergoing iOCT guided center sparing encountered condition in retina clinic Am J Ophthalmol 2007;144:299–301.

ILM peeling thereby sparing the areas with improved imaging and higher 19. Itakura H, Kishi S, Li D, Nitta K, Akiyama H.
Vitreous changes in high myopia observed by
of cystic changes at the fovea, showed resolution OCT devices. OCT evaluation swept-source optical coherence tomography.
Invest Ophthalmol Vis Sci. 2014;55:1447–1452.
worsening of BCVA or development of is necessary in pathological myopes
20. Kobayashi H, Kishi S. Vitreous surgery for
macular hole in the post-operative period. with unexplained visual loss as the highly myopic eyes with foveal detachment and
retinoschisis. Ophthalmology. 2003;110:1702-
‹ˆϐ‹…—Ž–‹‡• ƒ† …ŠƒŽŽ‡‰‡• ‹ •—”‰‡”› changes of MTM may be subtle and OCT 1707.

for MTM: is the diagnostic modality. Previous 21. Silva R. Myopic maculopathy: a review.
Ophthalmologica. 2012;228:197 213.
Following are the challenges faced refractive surgeries like phakic IOL leads
22. Mitry D, Zambarakji H. Recent trends in the
in surgery for MTM - –‘ †‹ˆϐ‹…—Ž–› ‹ •—”‰‹…ƒŽ ƒƒ‰‡‡– ‘ˆ management of maculopathy secondary to
pathological myopia. Graefes Arch Clin Exp
Ȉ Longer axial length: The patients these patients. The surgical treatment of Ophthalmol. 2012;250:3-13.

with myopic traction maculopathy myopic foveoschisis requires expertise 23. Shimada N, Ohno-Matsui K, Baba T, et al. Natural
course of macular retinoschisis in highly myopic
have pathological myopia and hence and may be complemented by newer eyes without macular hole or retinal detachment.
Am J Ophthalmol 2006;142:497–500.
long axial length. Long axial length intraoperative imaging modalities like
24. Kanda S, Uemura A, Skamoto Y, Kita H. Vitrectomy
ƒ› Ž‡ƒ† –‘ †‹ˆϐ‹…—Ž– ‹•–”—‡–ƒ–‹‘ intra-operative OCT to give improved with internal limiting membrane peeling for
macular retinoschisis and retinal detachment
ƒ† †‹ˆϐ‹…—Ž–› ‹ •—”‰‹…ƒŽ ƒ‡—˜‡” anatomical and visual outcomes. without macular hole in highly myopic eyes. Am
J Ophthalmol. 2003; 136: 177-180.
like ILM peeling.
25. Gaucher D, Haouchine B, Tadayoni R, et al. Long-
Ȉ Thinned out retina & severe CR REFERENCES term follow-up of high myopic foveoschisis:
degeneration: This lead to poor natural course and surgical outcome. Am J
contrast even after staining with 1. Saxena R, Vashist P, Tandon R, Pandey RM, Ophthalmol. 2007;143:455-562.

ǡ Ž‡ƒ†‹‰ –‘ †‹ˆϐ‹…—Ž–‹‡• ‹ ˜‹‡™‹‰ Bhardawaj A, Menon V, et al. Prevalence of myopia
the ILM and posterior pole. and its risk factors in urban school children in 26. Panozzo G, Mercanti A. Vitrectomy for myopic
Delhi: the North India myopia study (nim study) traction maculopathy. Arch Ophthalmol.
Ȉ Previous refractive surgery: Presence PLoS One. 2015;10:e117349. 2007;125:767-772.
of previous refractive surgery in
ƒ ˆ‡™ ‘ˆ ‘—” ‡›‡• Ž‡ƒ† –‘ †‹ˆϐ‹…—Ž– 2. Nangia V, Jonas JB, Sinha A, Matin A, Kulkarni 27. Ikuno Y, Sayanagi K, Ohji M, et al. Vitrectomy and
visualization of retina. Intraoperative M, Panda-Jonas S. Ocular axial length and its internal limiting membrane peeling for myopic
†‹ˆϐ‹…—Ž–‹‡• †—”‹‰ ‹ ’ƒ–‹‡– associations in an adult population of Central foveoschisis. Am J Ophthalmol. 2004;137:719–24.
with phakic-IOL (pIOL) included Rural India. The Central India Eye and Medical
problems in visualization due to Study.Ophthalmology. 2010;117:1360–66. 28. Brooks HL Jr. Macular hole surgery with and
aberrations produced at the edges without internal limiting membrane peeling.
of the optical zone of the pIOL. The 3. Sperduto RD, Seigel D, Roberts J, Rowland M. Ophthalmology. 2000;107:1939–49.
aberrations were present with Prevalence of myopia in the United States. Arch
„‘–Š –Š‡ …‘–ƒ…– ϐŽƒ– Ž‡• ȋ ŠƒŽƒ Ophthalmol. 1983;101:405-407. 29. Kwok AK, Lai TY, Man-Chan W, et al. Indocyanine
Direct SSV® lens Volk Optical, Inc.) green staining and removal of retinal internal
and wide angle viewing system 4. Wong TY, Ferreira A, Hughes R, et al. Epidemiology limiting membrane in stage 3 or 4 macular hole
(MiniQuad XL® contact wide angle and disease burden of pathologic myopia surgery. Br J Ophthalmol. 2003;87:71–4.
viewing lens, Volk Optical, Inc.). and myopic choroidal neovascularization:
The aberrations were more marked an evidence-based systematic review. Am J 30. Kwok AK, Lai TY. Internal limiting membrane
while using the Chalam direct SSV Ophthalmol. 2014;157:9-25. removal in macular hole surgery of severely
® lens probably due to a smaller myopic eyes: a case-control study. Br J Ophthalmol.
ϐ‹‡Ž† ‘ˆ ˜‹‡™ǡ ƒ Š‹‰Š‡” ƒ‰‹ϐ‹…ƒ–‹‘ 5. Takano M, Kishi S. Foveal retinoschisis and 2003;87:885–9.
and an increased depth of focus. The retinal detachment in severely myopic eyes
presence of ghost images at the edges with posterior staphyloma. Am J Ophthalmol 31. Taniuchi S, Hirakata A, Itoh Y, Hirota K, Inoue
‘ˆ –Š‡ ‘’–‹…ƒŽ œ‘‡ …ƒ—•‡† †‹ˆϐ‹…—Ž–‹‡• 1999;128:472–476. M. Vitrectomy with or without internal limiting
in intraoperative visualization membrane peeling for each stage of myopic
especially during critical steps such 6. Phillips CI: Retinal detachment at the posterior traction maculopathy. Retina. 2013;33:2018–25.
as internal limiting membrane pole. Br J Ophthalmol 1958; 42: 749–753.
peeling and peripheral vitrectomy. 32. Mateo C, Gómez-Resa MV, Burés-Jelstrup A,
The presence of such aberrations 7. Panozzo G, Mercanti A. Optical coherence Alkabes M. Surgical outcomes of macular buckling
–‘‘‰”ƒ’Š› ϐ‹†‹‰• ‹ ›‘’‹… –”ƒ…–‹‘ techniques for macular retinoschisis in highly
maculopathy. Arch Ophthalmol 2004;122:1455– myopic eyes. Saudi Journal of Ophthalmology.
1460. 2013;27:235-239.

8. Baba T, Ohno-Matsui K, Futagami S, et al. 33. Zhu Z, Ji X, Zhang J, Ke G. Posterior scleral
Prevalence and characteristics of foveal retinal reinforcement in the treatment of macular
detachment without macular hole in high myopia. retinoschisis in highly myopic patients. Clin
Am J Ophthalmol 2003;135:338–42. Experiment Ophthalmol. 2009;37:660–663.

9. Benhamou N, Massin P, Haouchine B, et al. 34. Shimada N, Sugamoto Y, Ogawa M, et al. Fovea-
Macular retinoschisis in highly myopic eyes. Am J sparing internal limiting membrane peeling for
’Š–ŠƒŽ‘Ž ʹͲͲʹʌͳ͵͵ǣ͹ͻͶȂͺͲͲǤ myopic traction maculopathy. Am J Ophthalmol.
2012;154:693–701.
10. Akiba J, Konno S, Sato E, et al. Retinal detachment
and retinoschisis detected by optical coherence 35. Yeh SI, Chang WC, Chen LJ. Vitrectomy without
tomography in a myopic eye with a macular hole. internal limiting membrane peeling for macular
Ophthalmic Surg Lasers 2000;31:240–2. retinoschisis and foveal detachment in highly
myopic eyes. ActaOphthalmol. 2008;86:219-224.
11. Polito A, Lanzetta P, Del Borrello M, et al.
Spontaneous resolution of a shallow detachment 36. Kwok AK, Lai TY, Yip WW. Vitrectomy and gas
of the macula in a highly myopic eye. Am J tamponade without internal limiting membrane
Ophthalmol 2003;135: 546–7. peeling for myopic foveoschisis. Br J Ophthalmol.

12. Ohno-Matsui K, Ikuno Y, Yasuda M, Murata 2005;89: 1180-1183.
T, Sakamoto T, Ishibashi T. Myopic Macular
Degeneration. Retina 5th Ed, China: Saunders,
2011;1263.

Financial Interest: Š‡ ƒ—–Š‘”• †‘ ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ
www. dos-times.org 11

RESEARCH METHODOLOGY

CLINICAL RESEARCH - BACK TO BASICS
UNDERSTANDING MODERN SCIENTIFIC METHODS:A SIMPLIFIEDVIEW

Mukesh Patil and Radhika Tandon

January always brings in a lot of changes in our lives. It is further strengthened during various stages of post-graduation
the beginning of a new year, bringing fresh hope for a new and our level of understanding is still further enhanced
beginning and an opportunity to disconnect and restart throughout our professional lifetime by virtue of exposure
or reboot our lives in a manner of speaking. Extending to studies actually conducted or kept informed of by reading

to an academic setting, there are postgraduates who journals, books, monographs, conference presentations, clinical

have completed their thesis work and submitted the trials in public domain etc. For those beginning this journey, a

bound copies for scrutiny by external examiners, others have brief review of important concepts can be helpful and for the

completed their MS/MD/DNB exams and are free to explore more experienced, a quick recapitulation of basics is always

the unchartered waters of furthering their career and fresh useful as a handy refreshing aide.

recruits who are joining ophthalmology full of joy and pride Š‡ ‘†‡” …‹‡–‹ϐ‹… ‡–Š‘†ǣ ƒ• ‘’’‘•‡† –‘ ‘Ž†‡” –‹‡•

for being selected after tough competition and enthusiasm for when physicians relied upon individual experience and taught

the path ahead and there are their teachers gearing up for the disciples or apprentices based on a purely individualistic

year ahead coaxing the previous students to publish the work approach with singular ideas and understanding, modern

and looking at interesting work to give to the new recruits. medicine and practice of clinical medicine is largely based on

There are also the entire community of ophthalmic care givers more objectivised systems or protocols of treatment resulting

looking forward to access to from controlled experimentation

new information gathered The basic idea for reviewing existing and documentation of outcomes
from various reliable research knowledge and searching published ƒ’’Ž›‹‰ •…‹‡–‹ϐ‹… ’”‹…‹’Ž‡• ‘ˆ
sources on the best available theory and practice. Inductive

knowledge and how best to articles is to have a good starting methods are applied to arrive
apply the shared experience in ƒ– †‡ϐ‹‹–‹˜‡ …‘…Ž—•‹‘• ™Š‹…Š
their own day to day practice. point for planning the study. Once the are applicable to draw general

We believe, the point is •–—†› –‘’‹… ‹• ‹†‡–‹ϐ‹‡†ǡ ’”‡’ƒ”‡ ƒ Ž‹•– conclusions about patient
well accepted that nothing we populations.
do every day is not affected of relevant topics important to have It is imperative that all

in some way or the other by enough background information to clinicians be encouraged to
someone else’s hard work and keep their curiosity alive in
perseverance and we must take understand the past and current level of their day to day practice, forever
a moment to recognize that understanding of the research idea. ”‡ϐŽ‡…–‹‰ ƒ† “—‡•–‹‘‹‰ –Š‡

we are all part of a continuum, encountered clinical scenarios

an unending path and are ™Š‹…Š †‘ ‘– ϐ‹– ‹ –‘ –Š‡

contributing in some way directly or indirectly to an ever established norms. This may be with respect to the clinical

expanding ocean of knowledge. With the advent of modern picture, pattern of disease, varied manifestation, response to

technology and advances in medical science, and the increased treatment, new modalities of therapy and even new surgical

ƒ……‡••‹„‹Ž‹–› ‘ˆ •…‹‡–‹ϐ‹… ‹ˆ‘”ƒ–‹‘ ƒ…”‘•• –Š‡ ™‘”Ž†™‹†‡ techniques. One can have uncommon manifestations of a

web, there is a bewildering plethora of research options to a common disease or common presentation of a rare disease and

young researcher which can be compounded with simultaneous miss the novelty if not aware or not curious enough to go in to

overload with lots of new concepts and work responsibilities. the depth of the case.

This article is written with a view to provide a simple guideline Š‡ •–ƒ‰‡• ‘ˆ ‘†‡” •…‹‡–‹ϐ‹… ‡–Š‘†• …ƒ „‡ „”‘ƒ†Ž›

on how to plan a research protocol and also present a simple divided in four stages (Table 1).

summary of how to interpret and analyze the existing body of Š‡•‡ ‡› •–ƒ‰‡• ‘ˆ ‘†‡” •…‹‡–‹ϐ‹… ‡–Š‘†• ƒ”‡

knowledge. translated into relevant steps for action by virtue of established

processes duly recognized over the years as effective means

REVISION OF BASICS: ESTABLISHING A BASELINE to reach the common goal of well conducted clinical research

BACKGROUND resulting in useful clinically applicable solutions which can

We all have studied the basics of biomedical research then be shared with others for wider dissemination (Figure 1).

in various stages of medical training, knowledge of which is

www. dos-times.org 13

RESEARCH METHODOLOGY

ƒ„Ž‡ ͳǣ –ƒ‰‡• ‘ˆ ‘†‡” •…‹‡–‹ϐ‹… ‡–Š‘†• to why the study was done. This is
important to understand the study
1. Observation Simply watching the natural course of a disease or its design and correctly process the
manifestations, impact on patient morbidity, quality of life or results and implications.
effect of treatment, available treatment options or protocols Ȉ ˆ ’”‡’ƒ”‹‰ –‘ •—„‹– ›‘—” ”‡•‡ƒ”…Š
and curiosity about how situations can be improved or in a paper for publishing- make sure
changed should lead to a wealth of ideas for clinical research. you explain nicely the rationale as
The possibilities are endless, limited only by the extent of our mentioned above.
imagination. A thorough up to date review or
awareness of literature to know the
2. Formulation of a Based on one’s current level of concern on any particular topic existing level of knowledge is paramount
to success in this process. This helps in
Hypothesis of interest driven by a priority to work in any particular area „‡––‡” †‡˜‡Ž‘’‹‰ ƒ† †‡ϐ‹‹‰ –Š‡ •–—†›
objectives and aim to be perfect for the
believed to be noteworthy, supported by the conviction that study
Objectives: Should be SMART
the research answer is deliverable, one frames a research Ȉ S’‡…‹ϐ‹…
Ȉ Measurable
“—‡•–‹‘ ƒ† –Š‡ ’”‘…‡‡†• –‘ ‡š’Ž‘”‡ –Š‡ ‹†‡ƒ ƒ† ϐ‹† ƒ Ȉ Appropriate
Ȉ Realistic
•…‹‡–‹ϐ‹… •‘Ž—–‹‘ –‘ ’”‘˜‡ ‘” †‹•’”‘˜‡ ‹–Ǥ Ȉ Time- bound

3. Testing the • ƒ ”‡•‡ƒ”…Š‡”ǡ ™‡ ’”‘…‡‡† ™‹–Š •…‹‡–‹ϐ‹… ’”‡…‹•‹‘ –‘ ƒ””ƒ‰‡ TIPS FOR PROCESS OF
Hypothesis to conduct our experiment or clinical trial in a standardized
manner to see if what we thought is true or proven to be EXPERIMENTAL DESIGN AND
incorrect
STUDY METHODS
4. Conclusion Based on the interpretation of the results or outcomes noted
during and as a result of the process of testing the hypothesis If planning a study-choose the best
or conduction of the experiment, we can arrive at a new level method to convert the research question
of understanding where we can state that the hypothesis is of interest in to a suitable experiment.
correct as conjectured and hence stands validated or was Pay attention to development of the
found to be not actually true and hence considered invalid or protocol specifying the study design, the
’ƒ”–Ž› …‘””‡…– ƒ† ƒ……‘”†‹‰Ž› ‘†‹ϐ‹ƒ„Ž‡Ǥ eligibility requirements, inclusion and
exclusion criteria, details of experimental
PRACTICAL TIPS AND PEARLS Ȉ Š‡ ”‡•—Ž–• ƒ”‡ †‡’‡†ƒ– ‘ –Š‡ intervention, description of controls,
FOR RESEARCH CAPABILITY question we ask †‡ϐ‹‡ ‘„Œ‡…–‹˜‡•ǡ •–ƒ–‡ ‡ƒ•—”ƒ„Ž‡
ENHANCEMENT outcomes. This can be remembered
Ȉ ™”‘‰ “—‡•–‹‘ ™‹ŽŽ Ž‡ƒ† –‘ ™”‘‰ by the mnemonic PICOTT i.e. Patients
The basic foundations listed above answer or Problem, Intervention/Exposure/
can be simply applied in keeping with Prognostic Factor, Comparison, Outcome,
individual requirements as the situation Ȉ ‡–Š‹…ƒŽ –‘ …‘†—…– ”‡•‡ƒ”…Š ™‹–Š ƒ Type of Question (Therapy/Diagnosis/
demands whether it is in choosing a wrong question Harm/Prognosis/Prevention), Type of
research project of interest, selecting a Study (Systematic Review, RCT, cohort/
thesis topic, interpreting results from a Ȉ Š‡ “—‡•–‹‘ –Šƒ– ™‡ •‡– ‘—– –‘ case control).
journal article, understanding original answer is our life long passion
™‘” ’”‡•‡–‡† ‹ •…‹‡–‹ϐ‹… ‡‡–‹‰• ‡–…Ǥ “He who asks a question is a fool If reading a journal or understanding
a research presentation-give adequate
The fundamental principles remain ˆ‘” ϔ‹˜‡ ‹—–‡•Ǣ Š‡ ™Š‘ †‘‡• ‘– ƒ• ƒ importance to the information provided
the same, it is only the application or question remains a fool forever” –Chinese as stated above to ascertain the adequacy
description which will change as the need Proverb and reliability of the study in suitable
arises. FINER criteria (Table 2) given by situations.
Hulley et al. highlights the practical tips TIPS FOR PROCESS FOR CONCEPT
for choosing a good research topic. If publishing a paper-give a thorough
DEVELOPMENT †‡•…”‹’–‹‘ ‘ˆ –Š‡ •’‡…‹ϐ‹‡† ƒ•’‡…–•
WHY IS IT SO IMPORTANT TO ASK explaining methodology and terms used.
THE RIGHT RESEARCH QUESTION? Ȉ ˆ ’Žƒ‹‰ ƒ •–—†›Ǧ…Š‘‘•‡ ƒ ƒ”‡ƒ
of interest based on perceived need,
Ȉ Š‡ ”‡•‡ƒ”…Š “—‡•–‹‘ ‰—‹†‡• ›‘—” …Ž‹‹…ƒŽ ”‡Ž‡˜ƒ…‡ ƒ† •…‹‡–‹ϐ‹…
research importance. State what is planned
and why. Frame a research question
Ȉ ‰‘‘† ”‡•‡ƒ”…Š “—‡•–‹‘ ‹• –Š‡ ‘•– and testable hypothesis.
important aspect of research
Ȉ ˆ ”‡ƒ†‹‰ ƒ Œ‘—”ƒŽ ‘” —†‡”•–ƒ†‹‰
a research presentation-look at
what the study reports pertaining

Dr. Rajendra Prasad Centre for Ophthalmic Sciences,AIIMS, New Delhi

Dr. Mukesh Patil MD, FICO Prof. Radhika Tandon MD, DNB, FRCOphth

14 DOS TIMES - JANUARY- FEBRUARY 2017

RESEARCH METHODOLOGY

TIPS FOR PROCESS OF STATISTICAL

INFERENCE

Pay attention to sample size-check if
adequate to make the results valid.

Check for variability and confounding
factors.

Look at the quantum of outcome
differences, the larger the difference, the
more likely that the null hypothesis will
be rejected.

In interpreting the results, keep in
mind the likelihood for errors. In certain
situations such as an exploratory study
or pilot trial, one may accept a higher
level of error than one would for a study
validating an established mode of therapy
‘” •–—†› †‡•‹‰‡† –‘ …Ž‡ƒ”Ž› †‡ϐ‹‡
preferred mode of treatment or test for
routine use. While it is true to say one can
never actually know if the null hypothesis
is true in comparing two techniques or
medications or situations, researchers
have established criteria to maintain
standard error rates for trials. Generally
type I error rates are set at 5% and/ or
type II error rates at 20% (Table 3)

There are several sources of possible
errors (Table 4) that need to be taken
care of in planning the protocol and/or
accounted for in performing the analysis.

Table 4: Summary of Potential
Sources of Error

Figure 1 Bias
Selection Bias
Table 2: FINER criteria for a good research topic Observer Bias

F Feasibility Resources (time, money, staff) Measurement Errors
Observer
I Interesting Interest to researcher or reviewer Instrument

N Novel New information? Confounding Factors
ƒŽ—ƒ„Ž‡ …‘ϐ‹”ƒ–‹‘ ‘ˆ ’”‡˜‹‘—• ϐ‹†‹‰ǫ
Variables which may affect/impact
E Ethical Following ethical guidelines? the values or recordings independent
of the study intervention/observation
R Relevant ϐŽ—‡…‡ ’”ƒ…–‹…‡ǫ are called confounding factors and can
Contribute to knowledge? be adjusted for statistics by multiviate
Can it change policy? analysis and using logistive regression
analysis.
Hulley et al, 2007
TIPS FOR SEARCHING AVAILABLE
ƒ„Ž‡ ͵ǣ š’Žƒƒ–‹‘ ‘ˆ Ƚ ƒ† Ⱦ ‡””‘”• KNOWLEDGE AND PREPARING
LITERATURE REVIEW
Decision/ Null Hypothesis is actually True Null Hypothesis is
Conclusion actually False The basic idea for reviewing existing
knowledge and searching published
Fail to Study Gp = Control Study Gp = Control articles is to have a good starting point for
Reject Null (Correct Result) (Decision incorrect Due to planning the study. Once the study topic is
Hypothesis Ⱦ ‘” ›’‡ ””‘”Ȍ ‹†‡–‹ϐ‹‡†ǡ ’”‡’ƒ”‡ ƒ Ž‹•– ‘ˆ ”‡Ž‡˜ƒ– –‘’‹…•
important to have enough background
Reject Null Study Gp outcome variable values Study Gp outcome variable information to understand the past and
Hypothesis current level of understanding of the
•–ƒ–‹•–‹…ƒŽŽ› •‹‰‹ϐ‹…ƒ–Ž› †‹ˆˆ‡”‡– ˆ”‘ values are statistically research idea. This includes but is not

…‘–”‘Ž•Ǥ ȋ ‡…‹•‹‘ ‹…‘””‡…– †—‡ –‘ Ƚ ‘” •‹‰‹ϐ‹…ƒ–Ž› †‹ˆˆ‡”‡– ˆ”‘

Type I Error) controls. (Correct Result)

www. dos-times.org 15

RESEARCH METHODOLOGY

limited to the following list of concepts Review of Literature: mention relation to the hypothesis and what is the
that should be clear before starting. details of previous studies classifying ϐ‹ƒŽ †‡…‹•‹‘ „ƒ•‡† ‘ –Š‡ ”‡•—Ž–•Ǥ
Ȉ ‘™ ‡…Šƒ‹• ‘ˆ †‹•‡ƒ•‡Ȁ‹–• the literature by topic and outlining
–Š‡ ”‡Ž‡˜ƒ– ϐ‹†‹‰•Ǥ ƒ‡ ƒ ƒ––‡’– Discussion: Analyse what the study
manifestations to provide a brief comment on the results mean in terms of relevance,
Ȉ ‘™ …‘…‡’–• ‹ †‹ƒ‰‘•‹•Ȁ implication of the existing body of impact, implications etc. Discuss the
knowledge with reference to the study ϐ‹†‹‰• ™‹–Š ”‡•’‡…– –‘ ’”‡˜‹‘—• •–—†‹‡•
management being planned and sum up the lacunae or and highlight any new features or any
Ȉ ‡˜‡Ž ‘ˆ ‹’‘”–ƒ…‡ ‘” ’”‹‘”‹–› ‘ˆ –Š‡ gaps in knowledge. ‹’‘”–ƒ– •’‡…‹ϐ‹… ϐ‹†‹‰•Ǥ Š‹ ƒ„‘—–
any inherent weakness of the study and
condition Methods: mention study design, mention if any, as also any particular
Ȉ ’‹†‡‹‘Ž‘‰› ‘ˆ –Š‡ †‹•‡ƒ•‡ study aim and objectives, sample strengths.
Ȉ ‘™ ”‹• ˆƒ…–‘”•Ȁ…‘ˆ‘—†‹‰ population, eligibility characteristics,
inclusion and exclusion criteria and the REFERENCES
variables detailed methodology to be carried out
Ȉ ‡’‘”–‡† ƒ……‡’–‡† ‡–Š‘†•Ȁ ƒ• ’‡” –Š‡ •–”ƒ–‡‰›Ǥ ‡ϐ‹‡ –‡”•ǡ 1 . Sackett DL. Evidence-based medicine.
provide grading systems, mention the Semin Perinatol. 1997;21:3-5.
protocols for study related steps parameters to be measured and outline
Ȉ ‡–ƒ‹Ž• ‘ˆ ƒ› †”—‰ ‹–‡”˜‡–‹‘• ‹ˆ the outcome measures. In short, explain 2. Straus SE, Sackett DL. Using research
what is to be done or what was done ϐ‹†‹‰• ‹ …Ž‹‹…ƒŽ ’”ƒ…–‹…‡Ǥ
᩿ǣ ”‹–‹•Š
planned if the study is completed and ready for Medical Journal. 1998;317:339-42.
Ȉ ”‡˜‹‘—• ‡š’‡”‹‡…‡ ‹ –‡”• reporting.
3. Hulley S, Cummings S, Browner W, et
of animal experiments/ In the study planning stage while al. Designing clinical research. 3rd ed.
psychopathology preparing the protocol, the description is Philadelphia (PA): Lippincott Williams
Ȉ ˆ †”—‰Ȁ•—”‰‹…ƒŽ ‹–‡”˜‡–‹‘ ’Žƒ‡† in future tense i.e. will be done etc, after and Wilkins; 2007.
then current status of acceptance of completion when writing the report/
the medication/procedure paper the methods are to be described in 4. Rosenberg W, Donald A. Evidence
Ȉ —–…‘‡ ‡ƒ•—”‡• —•‡† ‹ ’”‡˜‹‘—• past tense i.e. was done etc. based medicine: an approach to clinical
studies problem-solving. BMJ. 1995;310:1122-
Ȉ š’‡…–‡†Ȁƒ–‹…‹’ƒ–‡† „‡‡ϐ‹–• –‘ Results: Mention the study subjects, 6.
help determine desired effect in number of cases recruited, completion of
calculating sample size follow up and compliance, demographic 5. Rosenberg WM, Deeks J, Lusher A,
characteristics and baseline features. Snowball R, Dooley G, Sackett D.
TIPS FOR WRITING THE PROTOCOL/ Then describe the comparative values Improving searching skills and evidence
obtained and the corresponding retrieval. J R Coll Physicians Lond.
PAPER IF WORK COMPLETED statistical tests and inference 1998;32:557-63.

Headings Conclusion: State what the results 6. Sackett DL. Clinical Biostatistics.
mean with respect to the objectives in Canadian Medical Association Journal.
Introduction: give a simple 1978;119:424.
explanation of why the study is required
to be done or why you are interested in 7. Akobeng A. Understanding systematic
doing the study mentioning the rationale reviews and meta-analysis. Archives of
and study hypothesis. Sum up the main Disease in Childhood. 2005;90:845-48.
purpose of the study.
8. Akobeng A. Principles of evidence
based medicine. Archives of Disease in
Childhood. 2005;90:837-40.

Financial Interest: Š‡ ƒ—–Š‘”• †‘ ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ

16 DOS TIMES - JANUARY- FEBRUARY 2017

REFRACTIVE SURGERY

POST LASIK ECTASIA: RECENT CONCEPTS

Saranya Devi K, Rashmi Singh, Suresh Azimeera, M. Vanathi

Post lasik corneal ectasia is a sight threatening PTA (Percentage Tissue Altered)
complication characterized by progressive
steepening and thinning of cornea which can There is an integrated relationship between preoperative
be attributed to reduction in the biomechanical …‘”‡ƒŽ –Š‹…‡••ǡ ƒ„Žƒ–‹‘ †‡’–Š ȋ Ȍǡ ƒ† ϐŽƒ’ –Š‹…‡•• ȋ Ȍ
integrity of the cornea1,2. It might be due to in determining the relative amount of biomechanical change
operating on a preoperative weak cornea or due occurs after LASIK. Santhiago et al coined the term17,18 and
to operating on a normal cornea below the safe threshold investigated its association with ectasia. PTA can be described
level3. The estimated prevalence is 0.04-0.1% , though it is as PTA = (FT + AD)/central corneal thickness (CCT).18-21
underestimated and needs more extensive investigations and Santhiago et al17,18,20 have done studies to show that PTA should
research4. be taken into account as a screening method because a high
value of PTA(>40%) is important for the development of post-

RISK FACTORS LASIK ectasia in eyes with normal preoperative topography.
PTA more accurately represents the risk of ectasia than the

Corneal topography individual components that comprise it17-20. According to

Abnormal corneal topography is the most important the studies conducted by Santhiago et al, the risk of ectasia

warning sign for post lasik ectasia. Placido disc based automated rapidly increases with a PTA value >35%18,19,21. PTA provides

corneal topography has been found to be highly sensitive in a more individualized measure of biomechanical alteration

diagnosing keratoconus prior to reduction in visual acuity and as compared to residual bed thickness/CCT. Santhiago et al19

biomicroscopic changes5,6. The most overlooked risk factors revealed that even in eyes with suspicious corneal topography

are when the abnormal topographic changes are very subtle. –Š‡”‡ ‹• ƒ •‹‰‹ϐ‹…ƒ– …‘””‡Žƒ–‹‘ „‡–™‡‡ ˜ƒŽ—‡• ƒ† ‡…–ƒ•‹ƒ

An altered topographic pattern risk after LASIK. Eyes with signs

means a biomechanically fragile Post lasik corneal ectasia is a sight of topographic abnormality
structure, which carries a threatening complication characterized showed the development of
higher risk of ectasia if surgery ectasia even with lower PTA

is performed and tissue is by progressive steepening and thinning values.
removed3,7. Various indexes
have been implemented in of cornea which can be attributed to Residual bed thickness

the corneal topographers. reduction in the biomechanical integrity The residual stromal bed

Rabinowitz et al have proposed of the cornea. It might be due to operating (RSB) cutoff was proposed
inferior–superior (I–S) ratio8 on a preoperative weak cornea or due to based on clinical observations
values and the keratometry, but it lacks precision due

inferior–superior value, operating on a normal cornea below the to the fact that it is not an

simulated astigmatism, and safe threshold level individualized metric22. In 1998,
astigmatism (KISA)% index,9 –Š‡ …—–‘ˆˆ ˜ƒŽ—‡ ‘ˆ ʹͷͲ Ɋ ™ƒ•

which combines the central proposed to avoid ectasia after

keratometry power, the I–S value, the corneal-simulated LASIK. It was similar to the values proposed by Barraquer for

astigmatism , and a representation of the irregular astigmatism keratomileusis23. It was a value that was not too conservative

(smallest angle between two steep radii subtracted from 180°). and still allowing moderate and sometimes even high-level of

treatments.

Corneal Tomography

Placido disc based corneal topography is reliable to Central corneal thickness

diagnose most cases of keratoconus but still several indices Low central corneal thickness has also been found to be
ƒ† ƒ”–‹ϐ‹…‹ƒŽ ‹–‡ŽŽ‹‰‡…‡ ‡–Š‘†• Šƒ˜‡ „‡‡ ‹˜‡•–‹‰ƒ–‡† „› a weak predictor of ectasia24. The association with ectasia
different technologies like scanning-slit10 …Š‡‹’ϐŽ—‰11,12 dual risk is related to the fact that keratoconic corneas are thinner
…Š‡‹’ϐŽ—‰13,14 optical coherence tomography15 and very than normal corneas25,26. In normal eyes, the primary concern
high-frequency digital ultrasound16 that analyze the anterior is not only the actual corneal thickness but also how that
corneal curvature, posterior corneal surface, corneal thickness, thickness combined with excimer laser ablation translates
and epithelial mapping. Smadja et al studied a new screening into postoperative corneal biomechanics, which is the primary
ƒŽ‰‘”‹–Š —•‹‰ †—ƒŽ …Š‡‹’ϐŽ—‰ ƒƒŽ›œ‡” ƒ† •Š‘™‡† ƒ concept of PTA.
ƒ—–‘ƒ–‡† †‡…‹•‹‘ –”‡‡ …Žƒ••‹ϐ‹‡” –Šƒ– ƒŽŽ‘™• –Š‡ †‡–‡…–‹‘ ‘ˆ

keratoconus and forme fruste with promising combination of High myopia
•‡•‹–‹˜‹–› ƒ† •’‡…‹ϐ‹…‹–›Ǥ High myopia is similar to thin corneas in that they are

www. dos-times.org 17

REFRACTIVE SURGERY

both more prevalent among eyes RSB between 260 and 279 microns, Thus combined screening using
with keratoconus27 and when associated age between 22 to 25 years, corneal clinical and investigative tools is essential
with the disease, commonly present thickness between 481 to 510 microns in preventing post-LASIK ectasia.
with topographic or tomographic and MRSE between -10 to -12 D: each 2
abnormalities. In recent studies, the eyes points Histo-pathology and
™‹–Š ‡…–ƒ•‹ƒ ™‡”‡ •‹‰‹ϐ‹…ƒ–Ž› ‘”‡
myopic than controls but recently it has Asymmetric bowtie pattern in immunohistochemistry
been seen that the isolated prevalence of topography, RSB between 280 to 290
a high myopia (higher than 8 diopters) microns, age between 26 to 29 years, The characteristic histo-pathological
in eyes with normal topography is MRSE between -8 to -10 D: each one point
•‹‰‹ϐ‹…ƒ–Ž› Ž‘™Ǥ features of post-LASIK ectasia includes
Normal pattern or symmetric
Age bowtie, RSB more than 300 microns, age RSB thinning, hypocellular scar, increased
more than 30 years, corneal thickness
Age is the main source of information more than 510 microns, MRSE less than intralamellar cleft size, Bowman’s layer
about a patient’s intrinsic biomechanical -8 D: each 0 point.
properties28 and eyes that developed disruption. Transmission electron
ectasia tend to be younger than controls Other risk factors include eye
who did not develop ectasia. Young age rubbing, family history of keratoconus, microscopy (TEM) showed collagen
is probably the most controversial risk refractive instability, BCVA less than
factor. 20/20 preoperatively, and male gender lamellae thinning and decrease in the
and should be considered especially in
Prevention borderline cases. ‹–‡”ϐ‹„”‹Ž †‹•–ƒ…‡Ǥ

As with any disease, prevention is One main disadvantage of the Risk Immunohistochemistry shows
better than cure in post-LASIK ectasia as Score System is that any individual
well. Thorough pre-operative evaluation less than 22 years old is automatically abnormal epithelial basement membrane
is essential to decrease the risk of ectasia …Žƒ••‹ϐ‹‡† ƒ• ƒ– Ž‡ƒ•– Ǯ ‘†‡”ƒ–‡ ‹•ǯǡ
‹ ’ƒ–‹‡–•Ǥ †‡–‹ϐ‹…ƒ–‹‘ ‘ˆ ’”‡Ǧ despite the low incidence of ectasia in this (EBM), similar to that seen in other
existing risk factors is imperative, which age group.
can be done through various screening corneal pathologies such as keratoconus/
tools. Randleman2 et al have devised such Measures to avoid ectasia
a screening tool named “The Ectasia Risk bullous keratopathy32.
Score System”by reviewing a large series Ȉ ‹ƒ‰‘•‹• ‘ˆ ’”‡Ǧ‡š‹•–‹‰ …‘”‡ƒŽ
of LASIK patients. pathologies such as keratoconus Confocal microscopic evaluation
or forme-fruste keratoconus and
The Ectasia Risk Score System is a avoiding LASIK in such patients is in such patients reveal dense collagen
cumulative score system. Risk categories important.
based on points are: scars, decreased keratocyte density and
Ȉ ”‡Ǧ‘’‡”ƒ–‹˜‡Ž›ǡ ”‡•‹†—ƒŽ •–”‘ƒŽ „‡†
0-2 points=low risk, 3 thickness (RSB) must be calculated decreased transparency of the anterior
points=moderate risk, 4 points=high risk. „› †‡†—…–‹‰ –Š‡ ’”‡†‹…–‡† ϐŽƒ’
thickness (FT) and ablation depth stroma33.
The score system may be (AD) from the pre-operative central
summarized as 2: corneal thickness (CCT) i.e. RSB = MANAGEMENT
CCT- (AD+FT). The safety limit of
Abnormal topography, RSB <240 RSB is 300μ29,30. Contact lens
microns, corneal thickness less than 450
microns and Manifest refraction spherical Ȉ Ž•‘ –Š‡ ’ƒ–‹‡–ǯ• —•– „‡ To achieve good vision, various
equivalent (MRSE)> -14 D: each 4 points calculated, the safety limit of which contact lenses such as rigid gas permeable
is 40 % (RGP), custom wavefront-guided soft
Inferior steepening pattern or contact lens, hybrid lenses and tandem-
skewed radial axis in topography, RSB Ȉ ”‡Ǧ‘’‡”ƒ–‹˜‡ ‡•–‹ƒ–‹‘ ‘ˆ Ǧ soft contact lenses have been tried in
between 240 to 259 microns, age between value using pentacam is essential, post-LASIK ectasia patients34,35.
18 to 21 years, corneal thickness between the safe limit of which is 1.31
451 to 480 microns, MRSE between -12 to Intra-corneal ring segments (ICRS)
-14 D: each 3 points Ȉ –”ƒǦ‘’‡”ƒ–‹˜‡Ž› –Š‡ •—”‰‡‘
can measure the residual stromal Progressive ectasia can result in
thickness using intra-operative contact lens intolerance where intra-
’ƒ…Š›‡–”› ƒˆ–‡” Ž‹ˆ–‹‰ –Š‡ ϐŽƒ’Ǥ corneal ring segments may be of help.
Intacs (Addition Technology Inc. Des
Plaines, Illinois, USA) and KeraRings
(Ferrara Ophthalmics, Belo Horizonte,
Brazil) may improve visual function in
ecstatic corneas. ICRS implanted in the
…‘”‡ƒŽ ’‡”‹’Š‡”› ϐŽƒ––‡• –Š‡ …‘”‡ƒŽ
apex, thus decreasing the ectasia36.

Corneal collagen cross-linking
(CXL)

Collagen cross-linking has been
reported to halt the progression of

Cataract & Refractive, Cornea & Ocular Surface Services, Dr R.P. Centre for Ophthalmic Sciences,
All India Institute of Medical Sciences, New Delhi, India

Dr. Saranya Devi K MD, DNB Dr. Rashmi Singh MBBS Dr. Suresh Azimeera MBBS Prof. M.Vanathi MD

18 DOS TIMES - JANUARY- FEBRUARY 2017

REFRACTIVE SURGERY

ectasia37,38. CXL induces additional 11. Gilani F, Cortese M, Ambrósio RR, et 27. Krachmer JH, Feder RS, Belin MW.
covalent bonds between collagen al. Comprehensive anterior segment ‡”ƒ–‘…‘—• ƒ† ”‡Žƒ–‡† ‘‹ϐŽƒƒ–‘”›
molecules to increase corneal rigidity. normal values generated by rotating corneal thinning disorders. Surv Ophthalmol.
…Š‡‹’ϐŽ—‰ –‘‘‰”ƒ’Š›Ǥ
ƒ–ƒ”ƒ…– ‡ˆ”ƒ…– 1984;28:293–322
Combination treatments Surg.2013;39:1707–12.
28. Dawson DG, Randleman JB, Grossniklaus
ICRS and cross-linking may be 12. Steinberg J, Katz T, Lücke K, Frings HE. Corneal ectasia after excimer laser
combined to treat post-LASIK ectasia. A, Druchkiv V, Linke SJ. Screening keratorefractive surgery: histopathology,
Customized excimer laser ablation has for keratoconus with new dynamic ultrastructure, and pathophysiology.
also been reported in the treatment of „‹‘‡…Šƒ‹…ƒŽ ‹ ˜‹˜‘ …Š‡‹’ϐŽ—‰ ƒƒŽ›•‡•Ǥ Ophthalmology. 2008;115:2181–91
post-LASIK ectasia39,40. Cornea.2015;34:1404–1412.
29. Kohlhaas M, Spoerl E, Schilde T, Unger G,
Keratoplasty 13. Smadja D, Touboul D, Cohen A, et al. Wittig C, Pillunat LE. Biomechanical evidence
Detection of subclinical keratoconus using an of the distribution of cross-links in corneas
Lamellar or penetrating keratoplasty ƒ—–‘ƒ–‡† †‡…‹•‹‘ –”‡‡ …Žƒ••‹ϐ‹…ƒ–‹‘Ǥ 
–”‡ƒ–‡† ™‹–Š ”‹„‘ƪƒ˜‹ ƒ† —Ž–”ƒ˜‹‘Ž‡–
may be required in refractory cases to Ophthalmol. 2013;156:237–46 light. J Cataract Refract Surg 2006;32:279
achieve visual rehabilitation41. –83.
14. Smadja D, Santhiago MR, Mello GR, Krueger
CONCLUSION ǡ ‘Ž‹
ǡ ‘—„‘—Ž Ǥ ϐŽ—‡…‡ ‘ˆ –Š‡ 30. Randleman JB, Dawson DG, Grossniklaus
reference surface shape for discriminating HE, McCarey BE, Edelhauser HF. Analysis
Thorough preoperative evaluation between normal corneas, subclinical of quantitative cohesive tensile strength
and screening for high risk factors is keratoconus, and keratoconus. J Refract Surg. in normal human corneas: implications
imperative to prevent post LASIK ectasia. 2013;29:274–81. for refractive surgery. J Refract Surg
Use of newer screening tools such as PTA 2008;24:S85–S89.
should be encouraged apart from the 15. Rabinowitz YS, Li X, Canedo AL,
routine clinical screening. Ambrósio R, Jr, Bykhovskaya Y. Optical 31. Ambrósio Jr Renato, Ramos Isaac, Lopes
coherence tomography combined with Bernardo, Canedo Ana Laura Caiado, Correa
REFERENCES videokeratography to differentiate mild Rosane, Guerra Frederico et al. Assessing
keratoconus subtypes. J Refract Surg. ectasia susceptibility prior to LASIK: the
1. Randleman JB, Russell B, Ward MA, et al. Risk 2014;30:80–87. role of age and residual stromal bed (RSB)
factors and prognosis for corneal ectasia in conjunction to Belin-Ambrósio deviation
after LASIK. Ophthalmology 2003; 110:267– 16. Reinstein DZ, Gobbe M, Archer TJ, Silverman index (BAD-D). Rev. bras.oftalmol. 2014 Apr
75. RH, Coleman DJ. Epithelial, stromal, and total ; 73: 75-80.
corneal thickness in keratoconus: three-
2. Randleman JB, Woodward M, Lynn MJ, dimensional display with artemis very-high 32. Maguen E, Maguen B, Regev L, Ljubimov
Stulting RD. Risk assessment for ectasia after frequency digital ultrasound. J Refract Surg AV. Immunohistochemical evaluation
corneal refractive surgery. Ophthalmology 2010 Apr; 26: 259–71. of two corneal buttons with post-LASIK
2008; 115:37–50. keratectasia. Cornea. 2007;26:983-91.
17. Wilson SE, Klyce SD. Screening for corneal
3. Roberts CJ, Dupps WJ Jr. Biomechanics topographic abnormalities before refractive 33. Kymionis GD, Diakonis VF, Kalyvianaki
of corneal ectasia and biomechanical surgery. Ophthalmology. 1994;101:147–52. M, et al. One-year follow-up of corneal
treatments. J Cataract Refract Surg 2014; confocal microscopy after corneal cross-
40:991–98 18. Santhiago MR, Smadja D, Gomes BF, et al. linking in patients with post laser in situ
Association between the percent tissue keratosmileusis ectasia and keratoconus. Am
4. Randleman JB. Evaluating risk factors for altered and post-laser in situ keratomileusis J Ophthalmol. 2009;147:774-8.
ectasia: what is the goal of assessing risk? J ectasia in eyes with normal preoperative
Refract Surg. 2010;26:236–37 topography. Am J Ophthalmol. 2014;158:87– 34. Kymionis GD, Diakonis VF, Kalyvianaki
95 M, et al. One-year follow-up of corneal
5. Maeda N, Klyce S, Tano Y. Detection and confocal microscopy after corneal cross-
…Žƒ••‹ϐ‹…ƒ–‹‘ ‘ˆ ‹Ž† ‹””‡‰—Žƒ” ƒ•–‹‰ƒ–‹• 19. Santhiago MR, Smadja D, Wilson SE, Krueger linking in patients with post laser in situ
in patients with good visual acuity. Surv RR, Monteiro ML, Randleman JB. Role of keratosmileusis ectasia and keratoconus. Am
Ophthalmol. 1998;4:53–58 percent tissue altered on ectasia after LASIK J Ophthalmol. 2009;147:774-8.
in eyes with suspicious topography. J Refract
6. Maeda N, Klyce SD, Smolek M. Automated Surg. 2015;31:258–65. 35. Marsack JD, Parker KE, Niu Y,etal. On-eye
keratoconus screening with corneal performance of custom wavefront guided
topography analysis. Invest Ophthalmol Vis 20. Santhiago MR, Smadja D, Wilson SE, soft contact lenses in a habitual soft lens-
Sci. 1994;35:2749–2757 Randleman JB. Relative contribution of wearing keratoconic patient. J Refract
ϐŽƒ’ –Š‹…‡•• ƒ† ƒ„Žƒ–‹‘ †‡’–Š –‘ –Š‡ Surg2007; 23:960–64.
7. Piñero DP, Nieto JC, Lopez-Miguel A. percentage of tissue altered in ectasia after
Characterization of corneal structure laser in situ keratomileusis. J Cataract Refract 36. Alio J, Salem T, Artola A, et al. Intracorneal
in keratoconus. J Cataract Refract Surg. 2015;41:2493–2500 rings to correct corneal ectasia after laser in
Surg.2012;38:2167–83. situ keratomileusis. J Cataract Refract Surg
21. Santhiago MR, Kara-Junior N, Waring GO., 2002;28:1568-74.
8. Rabinowitz YS, McDonnell PJ. Computer- 4th Microkeratome versus femtosecond
assisted corneal topography in keratoconus. ϐŽƒ’•ǣ ƒ……—”ƒ…› ƒ† …‘’Ž‹…ƒ–‹‘•Ǥ —”” ’‹ 37. Kamburoglu G, Ertan A. Intacs implantation
Refract Corneal Surg.1989;5:400–408 Ophthalmol.2014;25:270–74. with sequential collagen cross-linking
treatment in post operative LASIK ectasia. J.
9. Rabinowitz YS, Rasheed K. KISA% index: a 22. Seiler T, Koufala K, Richter G. Iatrogenic Refract Surg2008; 24:S726–S729.
quantitative videokeratography algorithm keratectasia after laser in situ keratomileusis.
embodying minimal topographic criteria for J Refract Surg. 1998;14:312–17. 38. Vincigeurra P, Camesasca FI, Albe E, Trazza
diagnosing keratoconus. J Cataract Refract S. Corneal collagen cross-linking for ectasia
Surg. 1999;25:1327–35 23. Barraquer J. Keratomileusis for myopia and after excimer laser refractive surgery:1-year
aphakia. Ophthalmology.1981;88:701–708. results. J Refract Surg 2009; 22:1–12.
10. Saad A, Gatinel D. Topographic and
tomographic properties of forme fruste 24. Doughty MJ, Zaman ML. Human 39. Kymionis GD, Kontadakis GA, Kounis GA,
keratoconus corneas. Invest Ophthalmol Vis corneal thickness and its impact on et al. Simultaneous topography- guided
Sci. 2010;51:5546–55 intraocular pressure measures: a review PRK followed by corneal collagen cross-
and meta-analysis approach. Surv linking for keratoconus. J Refract Surg2009;
Ophthalmol.2000;44:367–408. 25:S807–S811.

25. Ambrósio R, Alonso RS, Luz A, Coca Velarde 40. Kanellopoulos AJ. Comparison of sequential

Ǥ ‘”‡ƒŽǦ–Š‹…‡•• •’ƒ–‹ƒŽ ’”‘ϐ‹Ž‡ ƒ† vs same-day simultaneous collagen cross-
corneal-volume distribution: tomographic linking and topography-guided PRK
indices to detect keratoconus. J Cataract for treatment of keratoconus. J Refract
Refract Surg. 2006;32:1851–59 Surg2009; 25:S8112–S8818.

26. Ruiseñor Vázquez PR, Galletti JD, Minguez 41. Bromley JG, Randleman JB. Treatment
ǡ ‡– ƒŽǤ ‡–ƒ…ƒ …Š‡‹’ϐŽ—‰ –‘‘‰”ƒ’Š› strategies for corneal ectasia. Curr Opin
ϐ‹†‹‰• ‹ –‘’‘‰”ƒ’Š‹…ƒŽŽ› ‘”ƒŽ ’ƒ–‹‡–• Ophthalmol. 2010;21:255-8.
and subclinical keratoconus cases. Am J
Ophthalmol. 2014;158:32–40.

Financial Interest: Š‡ ƒ—–Š‘”• †‘ ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ

www. dos-times.org 19

REFRACTIVE SURGERY

CONTOURA VISION TOPO GUIDED LASIK ON THE
WAVELIGHT PLATFORM

Sanjay Chaudhary, Sarika Jindal

Contoura Vision has two components, an Aspheric treatment of the cornea along

with correction of corneal aberrations or irregularities, based on topographic

measurements of the cornea

Lasik Surgery was introduced in late 1990’s and plan for every patient. The accuracy of Vario Topographer along
Šƒ• ƒ†˜ƒ…‡† •‹‰‹ϐ‹…ƒ–Ž› ‹ ’ƒ•– –™‘ †‡…ƒ†‡•Ǥ with speed and precision of Allegretto wavelight laser has given
Contoura Vision, a topography guided Lasik unsurpassed results.
–”‡ƒ–‡–ǡ ‹• –Š‡ Žƒ–‡•– ‡˜‘Ž—–‹‘ ‹ –Š‡ ϐ‹‡Ž† ‘ˆ
refractive surgery. Contoura Vision is proving itself Types of Laser Vision Corrections (LVC) for myopia
1. Conventional lasik

to be better than all other types of Laser Refractive 2. Aspheric lasik / Smile

procedures available today1,2. 3. Wavefront Guided lasik

Contoura Vision has two components, an Aspheric 4. Topo Guided lasik (Contoura Vision)

treatment of the cornea along with correction of corneal ‘˜‡–‹‘ƒŽ Žƒ•‹ –”‡ƒ–‡– ‹’Ž‹‡• ϐŽƒ––‡‹‰ ‘ˆ –Š‡

aberrations or irregularities, based on topographic central cornea to achieve a refractive correction. The edge of

‡ƒ•—”‡‡–• ‘ˆ –Š‡ …‘”‡ƒǤ – ‹• –Š‡ ϐ‹”•– –‘’‘‰”ƒ’Š› ‰—‹†‡† the treated area is blended with the peripheral cornea. The

Lasik to be approved by US Food and Drug Administration. It treated area is called the Optic Zone (OZ) and the blended area

became commercially available when a three year FDA study is called the Transition Zone (TZ). Rays of light from the Optic

results were presented at American academy of ophthalmology Zone focus on the retina while rays of light from the Peripheral

meeting in Nov 20153. zone focus in front of the retina, causing spherical aberration

Contoura vision uses wavelight ALLEGRETTO WAVE and loss of sharpness or contrast, with accompanied haloes and

EX500 or Eye-Q 400 Excimer laser system (Figure 1), along with glare. A prolate cornea is essentially converted into an oblate

wavelight ALLEGRO topolyzer and T-CAT treatment planning cornea (Figfure 3b).

software (Figure 2). These 3 help to create a unique treatment •’Š‡”‹… Žƒ•‹ –”‡ƒ–‡– ‹’Ž‹‡• ϐŽƒ––‡‹‰ ‘ˆ –Š‡ …‡–”ƒŽ

…‘”‡ƒǡ ƒ† „Ž‡†‹‰ –Š‡ …‡–”ƒŽ ϐŽƒ––‡‡† …—”˜‡ –‘ –Š‡

peripheral cornea in such a way that the central rays of light

and the peripheral rays of light come to a point focus on the

retina. Much more corneal tissue has to be removed at the

periphery to create this aspheric curve as shown in the picture

above (Figure 3a). It thus minimizes the amount of spherical

aberrations induced during Lasik surgery so there is virtually

no loss of contrast, and no haloes or glare. The treatment is also

referred to as Wave optimized lasik. But it does not address the

pre-existing higher order aberrations as in topography guided

Lasik4. SMILE is essentially an aspheric lasik as it involves

removal of a lenticule from within the cornea to create an

aspheric shape.

WaveLight FS200 Wavelight EX500 Wavefront guided Lasik corrects both the lower order and
Femtosecond Laser Excimer Laser the higher order aberrations of the eye. The data is obtained both
from the patient’s subjective refraction and from a wavefront
Figure 1: The Contoura Wavelight Refractive Suite aberrometer. Wavefront patterns are obtained by projecting

ab

Figure 2: Allegro Topolyser and T-CAT treatment planning software Figure 3a: Aspheric lasik. Figure 3b: Conventional lasik
www. dos-times.org 21

REFRACTIVE SURGERY

an array of light beams into the eye and Figure 4: Topographic images from Topolyser Vario
recording the location of corresponding
Ž‹‰Š– ”‡ϐŽ‡…–‡† ˆ”‘ –Š‡ ”‡–‹ƒǤ – –Š—• Figure 5: Treatment Planning
records the aberrations of the entire
optical pathway. Since it treats both lower and corneal apex. It then calculates height software along with manifest refraction
order and higher order aberrations, it data for areas where mire images are data and asphericity correction. T-CAT
results in enhanced visual sharpness and available (Figure 4). software then calculates treatment plan
vision in the order of 6/6. 6/5 or even 6/4. by combining manifest refraction data
The problem with wavefront guided lasik 8 pictures are captured out of which and corneal topographic image data from
is that all the aberrations in the optical four best are selected for reference. topolyzer.
pathway are treated on the cornea. Thus The success of topography guided lasik
the wavefront can be affected by vitreous treatment depends upon the accuracy T-CAT Software selects a single
‘’ƒ…‹–‹‡• ‘” ϐŽ‘ƒ–‡”•ǡ ƒ ƒ……‘‘†ƒ–‹‰ of the topographic images captured. or median (averaged) image showing
lens, changing lenticular aberrations Therefore, the surgeon should have an ‡†‹ƒ Š‡‹‰Š– ’”‘ϐ‹Ž‡Ǥ – –Š‡ •—„–”ƒ…–•
with age or lenticular opacities, an in-depth knowledge of how to capture „‡•– ϐ‹––‹‰ ƒ•’Š‡”‡ ˆ”‘ ‡†‹ƒ Š‡‹‰Š–
accommodating pupil, corneal opacities high quality images from topolyzer Vario ’”‘ϐ‹Ž‡ ƒ† ϐ‹–• ‡”‹‡ ‹–‘ ”‡•—Ž–‹‰
and corneal aberrations. It will give and what to look for on those images. The ‹””‡‰—Žƒ” Š‡‹‰Š– ’”‘ϐ‹Ž‡Ǥ ‡š– „ƒ•‡†
immediate good results, but any future surgeon then should personally plan and ‘ ƒ‹ˆ‡•– ”‡ˆ”ƒ…–‹‘ǡ ‘†‹ϐ‹…ƒ–‹‘
changes in the wavefront pathway may execute the treatment. While capturing of sphere, and cylinder/axis based on
not match the changes induced on the the topographic image, the patient should zernikes is done (Figure 5).
cornea leading to troublesome symptoms Ž‘‘ †‹”‡…–Ž› ƒ– –Š‡ ϐ‹šƒ–‹‘ –ƒ”‰‡– ƒ†
which will become almost impossible one should be careful enough to avoid T-CAT planning software thus
to correct. Because of this reason, it is centering errors, inadequate coverage, incorporates these two datas and treats
rapidly losing its importance. and shadows from nose that deteriorates lower order aberrations using refraction
the quality of topographic image. The and asphericity data and higher order
Topo Guided Lasik (Contoura ‹”‡• •Š‘—Ž† „‡ …”‹•’ ƒ† ™‡ŽŽ †‡ϐ‹‡† aberrations using topography data. The
Vision) involves correcting the manifest and the pupil should be accurately resultant data from T-CAT planning
refraction of the patient along with ‹†‡–‹ϐ‹‡†Ǥ ‘ ‰‡– ƒ ‰‘‘† –‘’‘‰”ƒ’Š‹… •‘ˆ–™ƒ”‡ ‹• ϐ‹ƒŽŽ› –”ƒ•ˆ‡””‡† –‘ ‡š…‹‡”
the corneal aberrations as elicited by image, topolyzer should capture atleast Laser machine and delivered to the eye.
a corneal topography. Since cornea 70% corneal surface and 100% of
contributes almost 75% of the total imaged pupil. The aim is to capture a T-CAT STUDY
higher order aberrations, and are more reproducible topographical image of the
static in nature, it makes sense to only corneal irregularity. How the concept evolved
treat corneal aberrations on the cornea.
This combined treatment gives excellent The topographic images are then Topography guided custom ablation
visual results in the order of 6/6, 6/5 or transferred to T-CAT treatment planning treatments have been performed
even 6/4. Since the topographer does not internationally since 2003. It has been
measures lower order optical aberrations
like spherical error and regular
astigmatism, the manifest refraction
is used. The results of this combined
treatment was recently brought forth by a
FDA conducted study which showed that
this is probably the best way to treat a
refractive error as of today.

PROCEDURE

Firstly to plan the Topography
guided custom ablation treatment,
corneal topography is done using
Topolyzer (Allegro Topolyzer, Alcon).
Allegro topolyzer diagnostic device is
a placido disc corneal topographer. It
detects mires edges, pupil margins and
calculates location of pupil area centroid

Eye7 Group of Eye Hospitals, New Delhi

Dr. Sanjay Chaudhary MBBS Dr. Sarika Jindal MBBS, DOMS
22 DOS TIMES - JANUARY- FEBRUARY 2017

REFRACTIVE SURGERY

mostly used for previously operated Figure 6: 68.8% of eyes had UCVA of 20/16 or Figure 7: 30.9% of eyes gained 1 or more lines
symptomatic eyes with decentered better at 3 months of UCVA compared to pre-operative BSCVA at
ablations, or small optical zones and 12 months
residual or induced corneal irregularities. for myopia and myopic astigmatism.
Alcon approached FDA to study T-CAT Topography-guided custom ablation Figure 8: 40.4% of eyes gained 1 or more lines
Lasik for irregular eye treatment but FDA at 12 months
required the study of primary (untreated –”‡ƒ–‡– ”‡•—Ž–‡† ‹ ƒ •‹‰‹ϐ‹…ƒ–
‡›‡•Ȍ ƒ• ϐ‹”•– •–‡’Ǥ Š‡”‡ˆ‘”‡ǡ Ž…‘ ƒ† reduction in the MRSE and cylinder vision and foreign body sensation, both of
study management contractor (CRC, Inc.) (both P <0.0001) reaching stability 3 which had a minimal increase in severity
developed the T-CAT LASIK protocol for months after treatment. Three months postoperatively. The 3.6% decrease in
the treatment of primary eyes with no postoperatively, 91.9% of 247eyes were severity of light sensitivity, 4.4% decrease
abnormalities other than refractive error. within 0.50 D of intended treatment. ‹ …‘’Žƒ‹–• ‘ˆ †‹ˆϐ‹…—Ž–› †”‹˜‹‰ ƒ– ‹‰Š–ǡ
͸ǤͶΨ †‡…”‡ƒ•‡ ‹ ”‡ƒ†‹‰ †‹ˆϐ‹…—Ž–›ǡ ƒ†
On 27thSeptember, 2013 USFDA At 3 months post operatively, 31.6% 2.4% reduction in glare complaints were
approved T-CAT LASIK for the treatment of eyes achieved the UCVA of 20/12.5 or ƒŽŽ •–ƒ–‹•–‹…ƒŽŽ› •‹‰‹ϐ‹…ƒ– ‹’”‘˜‡‡–•
of eyes with myopia and myopic better, 68.8% of eyes had UCVA of 20/16 after T-CAT Lasik.
astigmatism5. The T-CAT study was done or better, 92.7% of eyes had UCVA of
to evaluate the safety and effectiveness 20/20 or better (Figure 6). This study has shown that
of topography guided custom ablation Topography guided custom ablation
treatment for correction of myopia and Eyes treated with T-CAT treatment is no more a secondary
myopic astigmatism using ALLEGRO demonstrated a shift towards an procedure for correction of abnormalities
Topolyzer Topography System, T-CAT improvement in UCVA compared to after corneal refractive surgeries. Rather
treatment planning software and preoperative BSCVA with 29.6% of eyes it gives excellent results in normal eyes
Allegreto Wavelight Eye-Q Excimer Laser. gaining 1 or more lines of UCVA at 3 for correction of myopia and myopic
months compared with pre-operative astigmatism.
THE STUDY BSCVA. At 12 months, 30.9% of eyes
gained 1 or more lines of UCVA compared CONCLUSION
The study was a prospective, IRB to pre-operative BSCVA (Figure 7). The existing LASIK surgery in the
approved, non-randomized, multi-centric
study involving 9 investigation sites in In comparing preoperative BSCVA world today has matured and is capable
US for FDA, PMA submission. The study to postoperative BSCVA, 39.3% of eyes of superior refractive outcomes, however
included 249 eyes of 212 subjects that gained 1 or more lines at 3 months and Contoura Vision Topo-Guided LASIK is
had not undergone previous refractive 40.4% of eyes gained 1 or more lines another major breakthrough in LASIK
surgery and had stable refraction of upto at 12 months (Figure 8). One eye lost surgery. Contoura Vision Topo-Guided
-9.0 D of myopic spherical equivalent, more than 2 lines of BSCVA compared to LASIK surgery is able to surpass the
upto 8.0 D of sphere and upto -6.0 D of preoperatively, but none were recorded current standard of LASIK surgery as it
astigmatism. at 12 months. addresses both quantity and quality of
vision. FDA (USA) results support the fact
Eyes with previous refractive surgery, The safety of T-CAT was excellent, that, highest patient satisfaction rate of
•‹‰‹ϐ‹…ƒ– Ž‡–‹…—Žƒ” ƒ•–‹‰ƒ–‹•ǡ with 5 reports of loss of CDVA of 2 or ͻͺΨǡ ™Š‹…Š ‹• ϐ‹”•– ‘ˆ ‹–• ‹† †‘…—‡–‡†
abnormal topographies (eg, formefruste more lines at 1 month or later. All losses by FDA(USA) (earlier the best rate is
keratoconus), a calculated residual were transient, unrelated to the T-CAT ͻͶΨȌǤ ‘” –Š‡ ϐ‹”•– –‹‡ǡ ͵ͲΨ ‘ˆ –Š‡
stromal bed thickness less than 250 mm, LASIK treatment, and resolved by the patient had better UCVA post operatively
or other ocular pathology that might next postoperative follow-up visit. as compared to pre-op BSCVA. Contoura
affect the results of LASIK were excluded.
Contrast sensitivity testing
Corneal topographies for treatment demonstrated that the number of T-CAT
planning were obtained. Refractive LASIK-treated eyes with a clinically
treatment planning was based on pre- •‹‰‹ϐ‹…ƒ– ‹…”‡ƒ•‡ ‹ …‘–”ƒ•– •‡•‹–‹˜‹–›
operative manifest refraction and corneal was two- to three-folds higher than those
topography data. Both mechanical ‡›‡• ™‹–Š …Ž‹‹…ƒŽŽ› •‹‰θ‹ϐ‹…ƒ– †‡…”‡ƒ•‡•ǡ
microkeratomes and femtosecond both with and without glare under
Lasers were used to create corneal mesopic and photopic testing conditions
ϐŽƒ’•Ǥ ‡› ‘„Œ‡…–‹˜‡• ‘ˆ –Š‡ •–—†› ™‡”‡ at 3 and 6 months postoperatively.
safety criteria measured as changes in
BSCVA (Best spectacle corrected visual All categories of visual symptoms
acuity), incidence of adverse events and showed a reduction in severity 3
induced manifest refraction MRA. The months after the T-CAT LASIK procedure
effectiveness criteria were measured as compared to baseline, except double
visual acuity and refractive predictability
and stability. No retreatments were
performed in the study.

RESULTS

FDA data of T-CAT study showed that
T-CAT Lasik is safe and effective treatment

www. dos-times.org 23

REFRACTIVE SURGERY

Vision Topo Guided LASIK is the way 2. Tan J, Simon D, Mrochen M, Por YM. study of higher order aberrations.
forward for the refractive surgery as it Ophthalmic Surg Lasers Imaging 2011;
aims to measures and treat the complete Clinical results of topography-based 42:314–320 20.
corneal aberrations. 5. At 12 months. Summary of Safety
customized ablations for myopia and and Effectiveness Data, WaveLight®
Contoura Vision has the potential ALLEGRETTO® WAVE Eye-Q
to become the new standard in LASIK myopic astigmatism. J Refract Surg Excimer Laser System and the
surgery. ALLEGRO Topolyzer®. September
2012; 28:S829–S836. 27, 2013. Available at: http://www.
REFERENCES accessdata.fda.gov/cdrh_docs/pdf2/
3. Stulting RD, Fant BS, The T-CAT Study P020050S012b.pdf
1. Pasquali T, Krueger R. Topography-
guided Laser refractive surgery. Curr Group. Results of topography-guided
Opin Ophthalmol 2012; 23: 264-268.
laser in situ keratomileusis custom

ablation treatment with a refractive

excimer laser. J Cataract Refract Surg

2016;42:11-18

4. El Awady HE, Ghanem AA, Saleh SM.

Wavefront-optimized ablation versus

topography-guided customized

ablation in myopic LASIK: comparative

Financial Interest: Š‡ ƒ—–Š‘”• †‘ ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ

OBITUARY

Dr. S.K. Lall (18.02.1946 to 15.12.2016)

24 DOS TIMES - JANUARY- FEBRUARY 2017

CATARACT

FLUIDS IN EYE SURGERY

Shiv Mohan, Umang Mathur

D—”‹‰ ‹–”ƒ‘…—Žƒ” •—”‰‡”›ǡ ϐŽ—‹†• ”‡’Žƒ…‡ –Š‡ metabolism of intraocular tissues. Ascorbic acid (vitamin C) is
natural constituent of the eye and it is important perhaps the most unique constituent of the aqueous humor.
–‘ ’”‘–‡…– –Š‡ ‡›‡ •–”—…–—”‡•Ǥ Š‡ ϐŽ—‹†• ƒ‹Ž› Ascorbic acid is an important antioxidant, both in the aqueous
replace the aqueous humor in anterior chamber humor and in tissues of the anterior segment.
of the eye and vitreous in the posterior segment.
In this article we will discuss the properties of Carbohydrates

ƒ“—‡‘—• ƒ† ƒ˜ƒ‹Žƒ„Ž‡ ϐŽ—‹†• –Šƒ– ™‡ —•‡ ‹ ‘—” ‘…—Žƒ” •—”‰‡”‹‡•ǡ Glucose concentration in the aqueous is roughly 70%
their properties and advantages over each other. of that in plasma. The entry of glucose into the posterior

AQUEOUS HUMOR chamber occurs by facilitated diffusion. Aqueous glucose

levels are increased in people with diabetes, leading to higher

The aqueous humor is secreted by the ciliary epithelium concentrations in the lens.

which is a bilayer of polarised epithelial cells lining the ciliary

body; 2 cell layers of non pigmented ciliary epithelium (NPE) Glutathione

facing aqueous humor and pigmented ciliary epithelium(PE) Glutathione, an important tripeptide with a reactive
facing stroma. •—ŽϐŠ›†”›Ž ‰”‘—’ǡ ‹• ˆ‘—† ‹ –Š‡ ƒ“—‡‘—• Š—‘”Ǥ “—‡‘—•

Functions of aqueous glutathione may be derived by diffusion from the blood or by

an active-transport system in the ciliary epithelium analogous

1. It provides nutrients (eg, glucose and amino acids) to to that of the lens, it probably also arises by loss from the lens

support the function of tissues of the anterior segment, and cornea. Glutathione acts as a stabilizer of the redox state

such as the avascular lens, of the aqueous by reconverting

cornea, and trabecular —”‹‰ ‹–”ƒ‘…—Žƒ” •—”‰‡”›ǡ ϐŽ—‹†• ”‡’Žƒ…‡ ascorbate to its functional
meshwork form after oxidation, as well as
2. It removes the metabolic the natural constituent of the eye and it is by removing excess hydrogen

wastes from these tissues important to protect the eye structures. peroxide. Glutathione also
(eg, lactic acid, pyruvic serves as a substrate in the
acid) Š‡ ϐŽ—‹†• ƒ‹Ž› ”‡’Žƒ…‡ –Š‡ ƒ“—‡‘—• enzymatic conjugation, involved

3. It helps to maintain humor in anterior chamber of the eye ‹ –Š‡ …‡ŽŽ—Žƒ” †‡–‘š‹ϐ‹…ƒ–‹‘Ǥ – ‹•
appropriate intraocular important in protecting tissues
pressure (IOP). and vitreous in the posterior segment from oxidative damage and

Aqueous is devoid of blood oxidative stress and are highly

cells and is more than 99% plasma proteins. This provides an expressed in the ocular ciliary epithelium.

optically clear medium for the transmission of light along the

visual path. Urea

The aqueous humor composition is in dynamic equilibrium, The concentration of urea in the aqueous is between
†‡–‡”‹‡† „‘–Š „› ‹–• ”ƒ–‡ ‘ˆ ’”‘†—…–‹‘ ƒ† ‘—–ϐŽ‘™ ƒ† „› 80% and 90% of that in plasma. This compound is distributed
continuous exchanges with the tissues of the anterior segment. passively across nearly all biological membrane systems, and
It contains inorganic ions, organic anions, carbohydrate, its high aqueous:plasma ratio indicates that this small molecule
glutathione, urea, proteins, growth-modulatory factors, oxygen crosses the epithelial barrier quite readily. Urea is effective in
and carbon dioxide. the hyperosmotic infusion treatment for glaucoma. However,

Inorganic ions mannitol (with a molecular weight of 182 kD) is preferred to

urea because it crosses the barrier more easily.

The concentration of sodium, potassium, magnesium

in aqueous is same as plasma but the level of calcium is half Proteins

of plasma. Phosphate, iron, zinc, copper all are present in the The NPE cell layer establishes a blood-aqueous barrier
aqueous while chloride and bicarbonate are important anions. that prevents the diffusion of plasma proteins from the

Organic anions stroma into the posterior chamber. Normal aqueous contains

approximately 0.02 g of protein per 100 mL. The most abundant

Most abundant of organic anions in the aqueous is lactate ’Žƒ•ƒ ’”‘–‡‹• ‹†‡–‹ϐ‹‡† ‹ ƒ“—‡‘—• Š—‘” ƒ”‡ ƒŽ„—‹ ƒ†

and its concentration is always higher than that in plasma. transferrin, which together may account for 50% of all the

Aqueous levels of lactate is mainly resulting from the glycolytic protein content.

www. dos-times.org 25

CATARACT

Oxygen and carbon dioxide for the purpose of treating acidosis. Ȉ Bicarbonate: It is a buffering agent
Hartmann added lactate, which mitigates which helps to maintain the ph of
The corneal endothelium is critically changes in ph by acting as a buffer for solution.
dependent on the aqueous oxygen supply acid. Thus the solution became known as
ˆ‘” –Š‡ ƒ…–‹˜‡ ϐŽ—‹†Ǧ–”ƒ•’‘”– ‡…Šƒ‹•ǡ “Ringer’s lactate solution” or “Hartmann’s BALANCED SALT SOLUTION (BSS)
that maintains corneal transparency. The solution”.
lens and the endothelial lining of the In 1960, more physiological
trabecular meshwork also derive their Constituents solutions with ionic composition, pH and
oxygen supply from the aqueous humor. osmorality similar to aqueous humour
Oxygen, present in the aqueous humor Sodium, the major cation of the were developed and received the name of
is roughly one third of its concentration ‡š–”ƒ…‡ŽŽ—Žƒ” ϐŽ—‹†ǡ ˆ—…–‹‘• ’”‹ƒ”‹Ž› balanced salt solution (BSS)2. Additional
in the atmosphere. It is derived from the ‹ –Š‡ …‘–”‘Ž ‘ˆ ™ƒ–‡” †‹•–”‹„—–‹‘ǡ ϐŽ—‹† constituents in BSS over Lactated Ringer’s
blood supply to the ciliary body and iris, balance, and osmotic pressure of body solution are:
ˆ‘” –Š‡”‡ ‹• ‘ ‡– ϐŽ—š ‘ˆ ‘š›‰‡ ˆ”‘ –Š‡ ϐŽ—‹†•Ǥ ‘†‹— ‹• ƒŽ•‘ ƒ••‘…‹ƒ–‡† ™‹–Š Ȉ ‘†‹— …‹–”ƒ–‡ ƒ† ‘†‹— ƒ…‡–ƒ–‡ǣ
atmosphere across the cornea. chloride and bicarbonate in the regulation
‘ˆ –Š‡ ƒ…‹†Ǧ„ƒ•‡ ‡“—‹Ž‹„”‹— ‘ˆ „‘†› ϐŽ—‹†Ǥ present in the aqueous also.
The carbon dioxide content Ȉ ƒ‰‡•‹— …ŠŽ‘”‹†‡ǣ ƒ‰‡•‹—
of the aqueous humor contributes Potassium, the principal cation
approximately 3% of the total ‘ˆ ‹–”ƒ…‡ŽŽ—Žƒ” ϐŽ—‹†ǡ ’ƒ”–‹…‹’ƒ–‡• ‹ is essential for the Mg-ATPase
bicarbonate. This determines the pH of carbohydrate utilization and protein endothelial pump.
aqueous. It is continuously lost from the synthesis, and is critical in the regulation
aqueous by diffusion across the cornea of nerve conduction and muscle BSS PLUS SOLUTION
‹–‘ –Š‡ –‡ƒ” ϐ‹Ž ƒ† ƒ–‘•’Š‡”‡Ǥ contraction, particularly in the heart.
In 1973, a third generation of
Š› ™‡ ‡‡† •’‡…‹ϐ‹… ‹–”ƒ‘…—Žƒ” Chloride, the major extracellular irrigation solutions, named BSS Plus, was
ϐŽ—‹†•ǣ anion, closely follows the metabolism developed after studies by Edelhauser
of sodium, and changes in the acid-base ƒ† …‘ƒ—–Š‘”• ͵Ǧͷ ™Š‘ ˜‡”‹ϐ‹‡† –Šƒ–
Intraocular irrigating solutions „ƒŽƒ…‡ ‘ˆ –Š‡ „‘†› ƒ”‡ ”‡ϐŽ‡…–‡† „› the addition of glutathione, glucose and
perform multiple functions to preserve changes in the chloride concentration. bicarbonate to the irrigation solution
the viability of corneal endothelial cells would contribute to endothelial cell
during intraocular surgery; they protect Calcium, an important cation, function and survival in vitro. It is more
–Š‡ …‡ŽŽ• ˆ”‘ ϐŽ—…–—ƒ–‹‘• ‹ ’ ǡ ƒ‹–ƒ‹ provides the framework of bones and likely as aqueous composition. It has all
appropriate tonicity and electrolyte teeth in the form of calcium phosphate constituent of BSS with addition of:
concentration, and provide an energy and calcium carbonate. In the ionized Ȉ Glutathione: Glutathione is a
source1. form, calcium is essential for the
functional mechanism of the clotting component of many intraocular
Irrigating solutions available are: of blood, normal cardiac function, and irrigating solutions. It is a ubiquitous
1. Lactated ringer solution regulation of neuromuscular irritability. tripeptide (L-T-glutamyl-L-cysteinyl
2. Balanced salt solution (BSS) glycine) of mammalian cells. It
3. BSS plus Sodium lactate, is a racemic salt functions in reductive processes
4. Dextrose bicarbonate lactated containing both the levo form, which is that are essential for synthesizing
oxidized by the liver to bicarbonate, and and degrading proteins; forming
ringer solution the dextro form, which is converted to deoxyribonucleotides, precursors
glycogen. Lactate is slowly metabolized of DNA; regulating enzymes; and
LACTATED RINGER SOLUTION to carbon dioxide and water, accepting protecting cells against reactive
one hydrogen ion and resulting in the oxygen compounds and free radicals.
Ringer’s saline solution was invented formation of bicarbonate for the lactate Greater than 99% of intracellular
in the early 1880s by Sydney Ringer, consumed. These reactions depend on glutathione is normally in the
British physician and physiologist. Ringer oxidative cellular activity. reduced form which is abbreviated
was studying the beating of an isolated GSH. Oxidized glutathione is
frog heart outside of the body. He hoped DEXTROSE BICARBONATE RINGER abbreviated GSSH. Balanced Salt
to identify the substances in blood that Solution (BSS) Plus contains
would allow the isolated heart to beat LACTATE (DBRL) glutathione in the form GSSH. It has
normally for a time. The use of Ringer’s been reported that both reduced and
original solution of inorganic salts slowly The two additional constituents oxidized glutathione play important
became more popular. In the 1930s, the from Ringer’s lactate are: roles in maintaining the barrier
‘”‹‰‹ƒŽ •‘Ž—–‹‘ ™ƒ• ˆ—”–Š‡” ‘†‹ϐ‹‡† „› Ȉ Dextrose: It is an essential energy
American Pediatrician Alexis Hartmann
source for cells.

Dr. Shroff ’s Charity Eye Hospital, Kedar Nath Road, Daryaganj, New Delhi

Dr. Shiv Mohan MS Dr. Umang Mathur MS

26 DOS TIMES - JANUARY- FEBRUARY 2017

CATARACT

Table 1: Composition of aqueous humor and different irrigating solutions Dextrose bicarbonate Lactated Ringer’s
solution for irrigation has been reported
Chemical BSS BSS Ringer Aqueous Dextrose to be as effective as enriched BSS
plus lactate bicorbonate during cataract surgery14 and some
lactated ringer authors consider operating time and
solution irrigation volume to be important clinical
factors for endothelial cell loss during
NaCl 122.2 83.8 102 118.5 98.9 ’Šƒ…‘‡—Ž•‹ϐ‹…ƒ–‹‘ …ƒ–ƒ”ƒ…– •—”‰‡”›15.

KCl 5.08 10.1 4.00 3.9 3.88 PACKAGING

NaHCO2 25 -- -- 28 19.3 These solutions are available in
CaCl2 1.05 3.3 3 1.3 2.89 plastic bottles, glass and self collapsible
Dextrose 5.11 -- -- 2.9 4.82 bags. Any container for parenteral
product should maintain the integrity
Na2HPO4 3 -- -- 0.4 -- of the product as a sterile, pyrogen-free,
MgCl2 0.98 1.48 -- 0.8 -- high purity preparation till it is used.
Glutathione 0.3 -- -- 0.0001 --
Plastic bottles are made from a
Na lactate -- -- 28 4.7 27 homogenous blend of polypropylene
ƒ† –Š‡”‘’Žƒ•–‹… ‘†‹ϐ‹‡”ǡ •’‡…‹ϐ‹…ƒŽŽ›
Na citrate -- 5.78 -- ND -- developed for parenteral drugs. The
container is nontoxic and biologically
Na acetate -- 28.6 -- ND -- inert. The container is a closed system
and is not dependent upon entry of
Ascorbate -- -- -- 1.2 -- external air during administration.
While the manufacturer may ensure
Creatinine -- -- -- 0.04 -- sterile manufacturering and production,
microperforations during transportation
Protein -- -- -- 2.1 -- and sterile delivery of the solution before
administration cannot be strictly ensured.
Urea -- -- -- 6.1 -- Physical examination of the solution for
turbidity or contamination is also not
Osmolarity 305 298 259 301 279 possible through the translucent plastic
bottle. Therefore irrigating solutions in
Ph 7.4 8.2 6.6 7.49 7.83 plastic bottles are best avoided in eye
surgery.
function of the corneal endothelium, short-term, in vitro changes of endothelial
although there is no established Glass seems to be the material of
explanation for this mechanism. It cells8. These studies evaluated changes choice for containers for parenteral
also has been suggested that redox products. As a measure of abundant
cycling may play a role in cellular in endothelial cell morphology, density, precaution, some surgeons like to
defense against oxidative stress in autoclave glass bottles before use in
the anterior chamber. and corneal thickness among various intraocular surgery. However, this
Ȉ Dextrose: It acts as a energy source must be done with precaution and the
for the endothelial cells1 irrigating solutions using corneal tissue autoclaving cycle should release the
Ȉ Sodium bicorbonate and sodium pressure slowly over a 20 minute period
biphosphate: These both act as a test chambers4,9. Most of these studies ƒˆ–‡” –Š‡ •–‡”‹Ž‹œƒ–‹‘ ’‡”‹‘† ‹• ϐ‹‹•Š‡† •‘
physiological buffer in the solution6-7 that the liquids do not boil over when the
showed that the corneal endothelium pressure is released.
Comparisons of different solutions
appeared healthier, with a higher density According to pharmacopoeia
The theoretical advantage of BSS Plus •–ƒ†ƒ”†• ‰Žƒ•• „‘––Ž‡• ƒ”‡ …Žƒ••‹ϐ‹‡† ‹–‘
over Lactated Ringer’s would be that the ƒ† ’Š›•‹‘Ž‘‰‹… ϐ‹–‡•••ǡ ‹ˆ –Š‡ ‹””‹‰ƒ–‹‰ three varieties, Type 1 borosilicate highly
†‡š–”‘•‡ ™‘—Ž† „‡ Œ—•–‹ϐ‹‡† ƒ• ƒ ƒ–—”ƒŽ resistant glass, Type 2 dealkalized soda
energy source for endothelial cells, solution contained adenosine and/or lime glass, Type 3 standard untreated
sodium phosphate and bicarbonate are soda lime glass. All medical glass
physiological buffers found in aqueous glutathione3. Some in vivo studies using containers should be type 2 so that the
humour, and glutathione is a peptide pH of the solution not changed during
which is important as an antioxidant and different irrigating solutions show that heating or any other chemical reaction. So
as an agent maintaining the intercellular it is necessary to check that the RL or BSS
junctions. In addition, aqueous humour, postoperative corneal thickness and bottles are of medical grade glass before
BSS Plus and Lactated Ringer’s pH and sterilisation.
osmolarity are 7.38/304; 7.40/305 and endothelial cell count do not depend on
6.4/260, respectively. Lactated Ringer’s One more thing to notice that rubber
solution is hypotonic and slightly acidic irrigation volume and time but rather cork of glass bottles after autoclave
when compared with BSS Plus, which should be checked for any loosening.
seems to be more physiological, since it depend on the solution’s chemical
has pH and osmolarity values closer to
aqueous humour values. composition10-11. In fact, studies show

Multiple intraocular irrigating that enriched balanced salt solutions
solutions have been introduced based on
such as BSS Plus (glucose glutathione

bicarbonate solution) provide

characteristics similar to those of the

aqueous humour to maintain constant

intraocular conditions12-13.

However many clinical studies and

‘„•‡”˜ƒ–‹‘• Šƒ˜‡ ‘– ˆ‘—† •‹‰‹ϐ‹…ƒ–

differences between intraocular irrigating

solutions. Corneal perfusion studies

maintaining constant pH, osmolarity,

temperature, pressure, and electrolyte

concentrations with a dextrose-

adenosine - glutathione - bicarbonate-

Ringer’s and the same solution lacking

adenosine, glutathione, or both, found

these omissions to be inconsequential7.

www. dos-times.org 27

CATARACT

Now self collapsible containers are is associated with a corneal endothelial ͹Ǥ … ‡”‡›
ǡ ‡›ƒ
Ǥ ‹’Ž‹ϐ‹…ƒ–‹‘ ‘ˆ
also available for increased safety as these cell reduction similar to BSS Plus, if the glutathione - bicarbonate - Ringer solution:
bags collapse if any puncture happens in •—”‰‡‘ —•‡• Ž‹‹–‡† ’Šƒ…‘‡—Ž•‹ϐ‹…ƒ–‹‘ its effect on corneal thickness. Investigative
the bag. These are now becoming popular time and irrigation volume. Given the ophthalmology & visual science.
methods of delivery of ocular irrigation higher cost of BSS Plus, Lactated Ringer’s 1977;16:657-60.
products. solution works well for routine surgery.
Š‡”‡ ‹• ‘ …Ž‹‹…ƒŽŽ› •‹‰‹ϐ‹…ƒ– †‹ˆˆ‡”‡…‡ 8. Whikehart DR, Edelhauser HF. Glutathione
As a good quality assurance measure, for endothelial cell size preservation, in rabbit corneal endothelia: the effects
the batch number of each unit used for pleomorphism, or polymegethism ‘ˆ •‡Ž‡…–‡† ’‡”ˆ—•‹‘ ϐŽ—‹†•Ǥ ˜‡•–‹‰ƒ–‹˜‡
surgery should be noted. For added safety between BSS Plus and Ringer’s Lactate ophthalmology & visual science.
we can culture solution from a bottle of in routine extracapsular cataract surgery 1978;17:455-64.
a given lot to check any contamination with posterior chamber intraocular lens
before use in surgery. insertion. 9. Edelhauser HF, Van Horn DL, Schultz
RO, Hyndiuk RA. Comparative toxicity of
ADDITION OF ANTIBIOTICS On the other hand, for cataract intraocular irrigating solutions on the
operations that may require a higher corneal endothelium. American journal of
–‹„‹‘–‹…• ‹ –Š‡ ϐŽ—‹† ƒ’’‡ƒ”‡† volume of irrigation solution or longer ophthalmology. 1976;81:473-81.
to be nontoxic in terms of visual ’Šƒ…‘‡—Ž•‹ϐ‹…ƒ–‹‘ –‹‡ǡ Ž—• ƒ›
rehabilitation, anterior chamber reaction, contribute to lower endothelial cell loss 10. Matsuda M, Kinoshita S, Ohashi Y,
pachymetry, and corneal endothelial and clearer and compacter cornea in the Shimomura Y, Ohguro N, Okamoto H, Omoto
cell density16. The doses of vancomycin early post-operative period.Glutathione T, Hosotani H, Yoshida H. Comparison of the
ʹͲ Ɋ‰Ȁ ‹ –Š‡ ‹””‹‰ƒ–‹‰ •‘Ž—–‹‘ ƒ† may not be important for atraumatic effects of intraocular irrigating solutions
gentamicin 8 micrograms/mL, in the cataract surgery. Dextrose bicarbonate on the corneal endothelium in intraocular
‹””‹‰ƒ–‹‰ ϐŽ—‹†17-18. However, exposure to lactated Ringer’s solution has the lens implantation. British journal of
antibiotics for a short period of time, such ƒ†˜ƒ–ƒ‰‡ ‘ˆ ƒ •‹‰‹ϐ‹…ƒ– …‘•– •ƒ˜‹‰•Ǥ ophthalmology. 1991;75:476-9.
as during intraocular surgery, generally Moreover, Ringer’s Lactate solution is
has no effect on organisms commonly conveniently available from the pharmacy 11. Araie M, Shirasawa E, Hikita M. Effect of
responsible for endophthalmitis19. in hospital based operating rooms. oxidized glutathione on the barrier function
of the corneal endothelium. Investigative
TASS association: Toxic anterior Therefore, Ringer’s lactate is a ophthalmology & visual science.
segment syndrome (TASS) is a sterile good alternate for low cost, atraumatic 1988;29:1884-7.
’‘•–‘’‡”ƒ–‹˜‡ ‹ϐŽƒƒ–‘”› ”‡ƒ…–‹‘ cataract surgery, but in more complicated
caused by a noninfectious substance that surgeries or more time taking surgeries 12. Glasser DB, Matsuda M, Ellis JG, et al. Effects
enters the anterior segment, resulting BSS Plus may help in keeping better of intraocular irrigating solutions on the
in toxic damage to intraocular tissues. endothelial protection. corneal endothelium after in vivo anterior
Review of the literature indicates chamber irrigation. Am J Ophthalmol.
that possible causes of TASS include REFERENCES 1985;99:321–8
intraocular solutions with inappropriate
chemical composition, concentration, 1. Edelhauser HF. The resiliency of the corneal 13. Araie M. Barrier function of corneal
pH, or osmolality; preservatives; endothelium to refractive and intraocular endothelium and the intraocular irrigating
denatured ophthalmic viscosurgical surgery. Cornea. 2000;19:263-73. solutions. Archives of Ophthalmology.
devices; enzymatic detergents; bacterial 1986;104:435-8.
endotoxin; oxidized metal deposits 2. Merrill DL, Fleming TC, Girard LJ. The effects
and residues; and factors related to of physiologic balanced salt solutions and 14. Puckett TR, Peele KA, Howard RS, Kramer
intraocular lenses such as residues from normal saline on intraocular and extraocular KK. Intraocular irrigating solutions: A
polishing or sterilizing compounds. tissues. American Journal of Ophthalmology. randomized clinical trial of balanced salt
Sterile endophthalmitis due to suspected 1960;49:895-8. solution plus and dextrose bicarbonate
heat resistant endotoxins in the infusion lactated Ringer’s solution. Ophthalmology.
ϐŽ—‹† Šƒ˜‡ „‡‡ ”‡’‘”–‡† ˆ”‘ †‹ƒʹͲǤ 3. McCAREY BE, Edelhauser HF, Van Horn 1995;102:291-6.
An outbreak of TASS is an environmental DL. Functional and structural changes in
and toxic control issue that requires the corneal endothelium during in vitro 15. O’Grady GE, Alfonso E, Lee W, Batlle JF,
complete analysis of all medications and perfusion. Investigative Ophthalmology & Walkington PM, Parel JM. Comparison of
ϐŽ—‹†• —•‡† †—”‹‰ •—”‰‡”›ǡ ƒ• ™‡ŽŽ ƒ• Visual Science. 1973;12:410-7. low-and high-volume irrigation-aspiration
complete review of operating room and systems for extracapsular cataract extraction.
sterilization protocols21. 4. Edelhauser HF, Gonnering R, Van Horn American journal of ophthalmology.
DL. Intraocular irrigating solutions: A 1986;102:91-4.
CONCLUSION comparative study of BSS Plus and lactated
Ringer’s solution. Archives of Ophthalmology. 16. Espiritu CR, Caparas VL, Bolinao JG. Safety
In summary, for uncomplicated 1978;96:516-20. ‘ˆ ’”‘’Š›Žƒ…–‹… ‹–”ƒ…ƒ‡”ƒŽ ‘š‹ϐŽ‘šƒ…‹
intraocular surgeries, Ringer’s solution 0.5% ophthalmic solution in cataract surgery
5. Edelhauser HF, Van Horn DL, Hyndiuk RA, patients. Journal of Cataract & Refractive
Schultz RO. Intraocular irrigating solutions: Surgery. 2007 Jan 31;33:63-8.
Their effect on the corneal endothelium.
Archives of ophthalmology. 1975;93:648-57. 17. Schelonka LP, SaBell MA. Postcataract
endophthalmitis prophylaxis using irrigation,
6. McCarey BE, Polack FM, Marshall W. The incision hydration, and eye pressurization
’Šƒ…‘‡—Ž•‹ϐ‹…ƒ–‹‘ ’”‘…‡†—”‡Ǥ Ǥ Š‡ with vancomycin. Clinical ophthalmology
effect of intraocular irrigating solutions (Auckland, NZ). 2015;9:1337.
on the corneal endothelium. Investigative
Ophthalmology & Visual Science. 18. Gentile RC, Shukla S, Shah M, Ritterband DC,
1976;15:449-57. Engelbert M, Davis A, Hu DN. Microbiological
spectrum and antibiotic sensitivity in
endophthalmitis: a 25-year review.
Ophthalmology. 2014;121:1634-42.

19. Gritz DC, Cevallos AV, Smolin G, Whitcher JP.
Antibiotic supplementation of intraocular
irrigating solutions: an in vitro model
of antibacterial action. Ophthalmology.
1996;103:1204-9.

20. Patnaik B, Biswas C, Patnaik RK. Sterile
endophthalmitis in vitrectomised eyes due
to suspected heat resistant endotoxins
‹ –Š‡ ‹ˆ—•‹‘ ϐŽ—‹†Ǥ †‹ƒ Œ‘—”ƒŽ ‘ˆ
ophthalmology. 2004;52:127.

21. Mamalis N, Edelhauser HF, Dawson DG, Chew
J, LeBoyer RM, Werner L. Toxic anterior
segment syndrome. Journal of Cataract &
Refractive Surgery. 2006;32:324-33.

Financial Interest: Š‡ ƒ—–Š‘”• †‘ ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ

28 DOS TIMES - JANUARY- FEBRUARY 2017

OCULAR SURFACE

MUCOUS MEMBRANE GRAFTING – THE RESCUER!

J.K. Reddy, Rushita Kamdar, Shruthi Tara

Conjunctiva is a specialized mucous membrane that might be more suitable than oral mucosa3.
covers the posterior surface of eyelid and overlies
the anterior surface of the globe except for cornea. INDICATIONS
It contains numerous mucin producing goblet cells
for ocular lubrication. Ȉ —„ƒ…—–‡ •–ƒ‰‡ ‘ˆ –‡˜‡
‘Š•‘ǯ• ›†”‘‡ ȋ
Ȍ Ȃ —•‡ˆ—Ž
Destruction of the normal conjunctiva can in ocular surface reconstruction i.e symblepharon release,
‘……—” ‹ ƒ› ™ƒ›•ǡ •‹‰‹ϐ‹…ƒ– „‡‹‰ reconstruction, excision and replacement of keratinised
Ȉ ”ƒ—ƒǡ –Š‡”ƒŽ ‹Œ—”›ǡ …Š”‘‹… ‹ϐŽƒƒ–‹‘ Ž‡ƒ†‹‰ –‘ palpebral or bulbar conjunctiva. Entropion correction and
disorganized/ devitalized mucosa, lid margin reconstruction.
Ȉ Š‡‹…ƒŽ ‹Œ—”› Ȃ ƒ”‡† …‘–”ƒ…–‹‘ ƒ† •›„Ž‡’Šƒ”‘
Ȉ ϐŽƒƒ–‘”› Ȃ
ǡ Ž‡ƒ† –‘ …‘–”ƒ…–‹‘ ‘ˆ –Š‡ ‡’‹–Š‡Ž‹ƒŽ Ȉ ›„Ž‡’Šƒ”‘ •‡…‘†ƒ”› –‘ ƒŽƒŽ‹ „—”
surface Ȉ ‘ ’”‘–‡…– ƒ‰ƒ‹•– ‡Ž– ƒ† ˆ‘” ‡ˆˆ‡…–‹˜‡ ”‡–‡–‹‘ ‘ˆ
Ȉ ƒ–”‘‰‡‹…Ǧ •‹‰‹ϐ‹…ƒ– Ž‘•• ‘ˆ …‘Œ—…–‹˜ƒ
Re-establishing the ocular surfaces and the normal tear ‡”ƒ–‘’”‘•–Š‡•‹• ‹ ’ƒ–‹‡–• ™‹–Š ’‘‘” –‡ƒ” ϐ‹Ž •–ƒ–—•Ǥ
ϐ‹Ž …‘’‘•‹–‹‘ ”‡“—‹”‡• ”‡’Žƒ…‡‡– ‘ˆ †‡•–”‘›‡† —…‘•ƒ Ȉ ‡…—””‡– ’–‡”›‰‹—ǡ Ž‹„ƒŽ †‡”‘‹†• ™‹–Š •›’Ž‡’Šƒ”‘
preferentially with tissue consisting of goblet cells capable of Ȉ ‘Œ—…–‹˜ƒŽ •…ƒ””‹‰ ˆ”‘ ’”‡˜‹‘—• •—”‰‡”› ‘” –”ƒ—ƒ
mucin production. Ȉ ‡’Žƒ…‡‡– ‘•–‡”‹‘” Žƒ‡ŽŽƒ ‘ˆ –Š‡ ‡›‡Ž‹† ƒ• ‹ …‹…ƒ–”‹…‹ƒŽ
The major aim of treatment is to stabilize and re-establish
the ocular surface, separate symblepharon to allow bulbar entropion
motility, ensure adequate wetting of the eye, and prevent further Ȉ ‘–”ƒ…–‡† •‘…‡–
…‘’Ž‹…ƒ–‹‘• †—‡ –‘ •…ƒ””‹‰ ƒ† …Š”‘‹… ‹ϐŽƒƒ–‹‘Ǥ Ȉ ‘Œ—…–‹˜ƒŽ ”‡’Žƒ…‡‡– ˆ‘ŽŽ‘™‹‰ ƒ •‘…‡– ”‡…‘•–”—…–‹‘
This procedure may be supplemented with limbal stem cell Ȉ ‹–Š ‹‘” •ƒŽ‹˜ƒ”› ‰Žƒ† –”ƒ•’Žƒ– ‹ †”› ‡›‡ –”‡ƒ–‡–
transplantation from the fellow eye (if healthy) or cultivated Ȉ ‘Œ—…–‹˜ƒŽ ”‡’Žƒ…‡‡– ˆ‘ŽŽ‘™‹‰ –—‘” ”‡•‡…–‹‘Ǧ
stem cells over an AMG.
This procedure may be followed by optical rehabilitation Squamous Cell Carcinoma of lid, Malignant Melanoma of
including keratoplasty. Optical rehabilitation can only be conjuntiva, eyelid malignancies
achieved after the ocular surface has been re-established and Ȉ ƒ–‡ ‘•‡– –”ƒ„‡…—Ž‡…–‘› „Ž‡„ Ž‡ƒ•
‘…—Žƒ” ™‡––‹‰ ‹• •—ˆϐ‹…‹‡– –‘ •—’’‘”– ƒ …‘”‡ƒŽ ‰”ƒˆ–Ǥ Though mucosal sites are involved in SJS, the oralmucosal
lesions like the skin lesions are probably self-limiting making it
possible to harvest mucosa from the lip. Mucousmembrane from
the lip can be harvested with ease and doesnot leave behind any
•‹‰‹ϐ‹…ƒ– •…ƒ””‹‰ ‘” †‡ˆ‘”‹–›Ǥ Ž•‘ǡ–Š‡ ’”‡•‡…‡ ‘ˆ ‰‘„Ž‡–
cells in the lip mucosa( it is also thought that some goblet cells

CHOICE OF GRAFT MATERIAL may be present in the labial mucosa more so posteriorly) can

contribute tothe mucin in the eye with stabilization of the tear

Addition of epithelial tissue, or a basement membrane ϐ‹Ž –‘ •‘‡‡š–‡– ƒ• ‘–‡† „› –Š‡ ‹’”‘˜‡‡– ‹ …Š‹”‡”

which can be populated by wetting values4.
healthy host epithelial cells, Prerequisite for successful autologous
Oral mucosal graft

is required to reconstruct and mucosal grafting is adequate suppression is commonly used during
maintain the ocular surface of the underlying ocular surface oculoplastic surgeries to
and fornix. The ideal epithelial replace the ocular (corneal and

graft tissue shouldhave the ‹ϐŽƒƒ–‹‘Ǥ Š‡ ’”‘…‡†—”‡ ‹• —•—ƒŽŽ› conjunctival) surface as well
same cosmetic appearance as as for reconstruction of the
conjunctiva, resulting in the unsuccessful during the acute phase of a eyelid, the fornix and the socket.

formation of normal tissue cicatricial conjunctivitis with active and It is also used for correcting
and celltypes, including goblet lid margin keratinization in
cells, and prevent postoperative •‡˜‡”‡ ‹ϐŽƒƒ–‹‘ Stevens-Johnson syndrome

cicatrisation. So, when healthy to reduce ocular surface

conjunctivais available, it is the ideal material for grafting. ‹ϐŽƒƒ–‹‘ ƒ† –‘ ‹’”‘˜‡ ’ƒ–‹‡– …‘ˆ‘”– ƒ† ˜‹•—ƒŽ ƒ…—‹–›Ǥ

The choice of the ideal conjunctiva-replacing tissue or Combined use of oral mucosa and preserved amniotic

material depends on the predominantly lost conjunctival membrane can be considered for advanced cicatricial

function in the individual situation. In cases when only the conjunctivitis.

conjunctival extension has to be restored, amniotic membrane Residual compromised ocular surface due to limbal stem

‰”ƒˆ–‹‰ …ƒ „‡ ƒ •—ˆϐ‹…‹‡– •‘Ž—–‹‘ǡ „—– ‘ˆ Ž‹‹–‡† —•‡ ‹ …ƒ•‡• …‡ŽŽ †‡ϐ‹…‹‡…› —•—ƒŽŽ› ‡‡†• –‘ „‡ ˆ—”–Š‡” ƒ††”‡••‡† „‡…ƒ—•‡

™‹–Š –‹••—‡ †‡ϐ‹…‹‡…›Ǥ  …‘Œ—…–‹˜ƒŽ ’ƒ–Š‘Ž‘‰‹‡• ™‹–Š •‡˜‡”‡ the procedure does not provide an adequate source of limbal

goblet cell dysfunction (e.g. ocular pemphigoid), grafts of stem cells. Limbal stem cell transplantation (Simple Limbal

—…‘•ƒ …‘–ƒ‹‹‰ ‰‘„Ž‡– …‡ŽŽ• ƒ–—”ƒŽŽ› ‹ •—ˆϐ‹…‹‡– —„‡” epithelial transplantantation or Cultivated limbal epithelial

www. dos-times.org 29

OCULAR SURFACE

Table 1: Tissue options for ocular surface reconstruction and fornix formation1

Graft material Stiffness Stability Goblet cells Epithelial Availability(For Source Cosmesis
stem cells extensive repairs)
Conjunctiva Excellent
Tarsus - ++ + - Autologous Excellent
Full thickness Poor
buccal MMG + ++ + + - Autologous
Split thickness
MMG + ++ - + ++ Autologous
Hard palate
Nasal mucosa + ++ - ++ Autologous Good
Preserved
Amniotic ++ ++ - + + Autologous Good
membrane graft + + ++ + + Autologous Fair

- - - - +++ Heterologous Excellent

Table 2: Type of MMG ‘…—Žƒ” •—”ˆƒ…‡ ‹ϐŽƒƒ–‹‘ ƒ†
discomfort in these eyes. It accounts
Split thickness MMG Full thickness MMG for a deterioration of the ocular surface
Contracts less over years and also contributes to the
Contraction Contracts more Persistent pinkish high failure rates of attempts at surface
more reconstruction and visual rehabilitative
Color Mild pinkish more procedures.
Less suitable
Glandularity Less More suitable The treatment of SJS aims at the
restoration of the anatomical structures
Bulkiness Less and physiologic properties of the ocular
surface. In chronic phase, autologous or
Bulbar conjunctival replacement More suitable allogenic limbo-conjunctival graft are
best used for transplantation. However,
Fornix reconstruction Less suitable due to unavailability of the conjunctival
tissue for transplantation in cases of
transplantation) should be done in the meibum is affected by meibomian bilateral involvement, another autologous
addition to the Mucous membrane gland metaplasia. The lid margin changes graft, i.e, mucosal graft with amniotic
grafting to replenish the lost limbal cells5. occurring include meibomian gland membrane is used.
metaplasia, trichiasis, punctal scarring,
SJS AND OTHER OCULAR and lid margin keratinization. LID MARGIN KERATINISATION
CICATRIZING CONDITION
In addition, the presence of MMG should be done for lid margin
™‹–Š‹ –Š‡ ϐ‹”•– ʹ ™‡‡• ‘ˆ ‘•‡– symblepharon alters the stability of the keratinization as a surface stabilization
of SJS is believed to reduce the incidence –‡ƒ” ϐ‹ŽǤ Š‡ „Ž‹Ǧ”‡Žƒ–‡† ‹…”‘–”ƒ—ƒ procedure which helps in anatomical
of chronic sequelae. Most often, patients because of the lid margin keratinization, ”‡•–‘”ƒ–‹‘ ‘ˆ –Š‡ ‹ϐŽƒ‡† ‘…—Žƒ” •—”ˆƒ…‡Ǥ
consult an ophthalmologist with severe which is worsened by the lipid and
ocular sequelae only after the resolution ƒ“—‡‘—• –‡ƒ” †‡ϐ‹…‹‡…‹‡• Ž‡ƒ†• –‘ Excision of the keratinized area and
of skin lesion and have already various continuous trauma to the limbal stem its replacement by mucous membrane
untoward alterations of the ocular surface cells6. helps restore the intactness of the
set in. mucocutaneous junction and prevents
Destruction of limbal stem cells crossover of the keratinized epithelium,
OCULAR SURFACE DISTURBANCES results in replacement of corneal thus acting as a barrier.This is proved
IN SJS epithelium by conjunctival epithelium. by the stopping short of the keratinized
This destruction to limbal stem cells are adjacent to the transplanted mucous
In SJS, a disturbance in all 3 is ongoing in SJS because of persistent membrane as was observed by Iyer et al
…‘’‘‡–• ‘ˆ –Š‡ –‡ƒ” ϐ‹Ž‘……—”•Ǥ Š‡ ‹ϐŽƒƒ–‹‘Ǥ Š‡ ’”‹‡ …ƒ—•‡• ˆ‘” –Š‹• in their case series.
mucin layer is disturbed by destruction ‹ϐŽƒƒ–‹‘ ‹…Ž—†‡ †”› ‡›‡ǡ Ž‹† ƒ”‰‹
of theconjunctival cells, aqueous layer …Šƒ‰‡•ǡ ƒ† …‘Œ—…–‹˜ƒŽ ‹ϐŽƒƒ–‹‘Ǥ
by scarring around the ductules, and
The issue of lid margin keratinization,
is another important cause for persistent

Sankara Eye Care Institutions, Coimbatore, India

Dr. J.K. Reddy MS Dr. Rushita Kamdar MBBS Dr. Shruthi Tara MBBS

30 DOS TIMES - JANUARY- FEBRUARY 2017

OCULAR SURFACE

Table 3: Site of mucosal graft

Hard palate Labial Buccal mucosa Nasal mucosa2
mucosal grafts (Lower lip preferred)
Rich in mucosal glands both
Advantages Thickest Easy access, Reepithelises Yields more material subepithelial and intraepithelial
Disadvantages Least contraction in 2 weeks ‡…Š‹…ƒŽ †‹ˆϐ‹…—Ž–› ƒ†
instrumentation to harvest it.
‹ˆϐ‹…—Ž– ƒ……‡•• Carries only subepithelial Less accessible
mucosal glands. Carries only subepithelial
Lacks intraepithelial mucosal glands
goblet cells. Lacks intraepithelial goblet
cells

CHEMICAL INJURY without any evidence of infection and The size of the donor should be 25
submucosal scarring) was done with – 30 % larger than the recipient size to
Chemical agents destroy the vascular subsequent use of chlorhexidine or Iodine allow for shrinkage.
network, which can lead to scleral and mouthwash 4 times a day for 5 days.
limbal ischemia. Ultimately, the cornea DONOR SITE
and sclera can melt, which presents a SURGICAL PROCEDURE
major threat to globe integrity. A portion of gauze soaked with
Full thickness MMG adrenaline is applied. It should not be
The buccal mucosa, in histology and cauterized to reduce pain. The oral
physiology, resembles the conjunctiva The lower lip is preferred for full mucosal will resurface in 2-3 days.
and is a substitute for the conjunctiva thickness grafts because of excellent Alternatively an AMG may be used to
in repairing sclerocorneal melts in exposure for dissection.Under GA, towel cover the donor area thereby alleviating
serious chemical burns7. MMG grafting clamps are placed at the end of the lower the post operative discomfort.
in acute chemical and thermal injuries lip, which is everted over an assistant’s
fastens ocular surface repair process and ϐ‹‰‡”Ǥ Ž–‡”ƒ–‹˜‡Ž›ǡ ͶǦͲ ‹Ž –”ƒ…–‹‘ RECIPIENT DISSECTION
prevents unwanted sequelae. suture may be used to evert lip. The area to
be grafted is marked with a gentian violet Upon adequate control of
RECURRENT (REFRACTORY) marker. The graft size must be 15-20% ‹ϐŽƒƒ–‹‘ǡ –Š‡ †‡•‡ …‘”‡ƒŽ ’ƒ—•
PTERYGIUM larger than desired recipient size to allow or conjunctival scars can be excised from
for shrinkage. Care must be taken not to the ocular surface, and the symblepharon
Inappropriate and excessive include the mucocutaneous junction (the or lid adhesions can be lysed via careful
dissection of the conjunctiva leads to vermillion border) or alter the gum line. dissection with respect to the tissue
conjunctival scarring and shortening and For the cheek (buccal MMG), adjust the plane.
at times, restricting the eye movements. grafts position to avoid the opening of the
Split thickness grafts (usually 0.1- 0.2 parotid duct, usually opposite the second This is done after subconjunctival
Ȍ ƒ”‡ ƒ ‰‘‘† •—„•–‹–—–‡ ˆ‘” ‹•—ˆϐ‹…‹‡– upper molar. ‹ϐ‹Ž–”ƒ–‹‘ ™‹–Š ͳΨ Ž‹†‘…ƒ‹‡ ™‹–Š
conjunctiva8/ Also, MMG is required to epinephrine.
prevent two surfaces without epithelium Outlined region is ballooned up with
from being opposed, thus preventing Xylocaine. A No.15 surgical blade is used •—’‡”ϐ‹…‹ƒŽ Žƒ‡ŽŽƒ” †‹••‡…–‹‘ ‘ˆ
symblepharon formation. to make the entire full thickness incision. the cornea could be done to separate the
The graft is then harvested with blunt conjunctivo-corneal adhesion, followed
Mucosal grafts provide protective scissors dissection, taking care not to by release of symblepharon between
layer over keratoprosthesis especially include submucosal fat and bucccinator palpebral and bulbar conjunctiva.The
in cases with severely compromised muscle. The graft may be further thinned anterior and posterior lamellae of lid are
ocular surface like SJS/ Chemical burns. out by placing the mucosal surface tautly divided. Care should be taken to avoid
It helps structurally and functionally to ‘˜‡” ƒ ‰Ž‘˜‡† ‹†‡š ϐ‹‰‡”ƒ† –”‹‹‰ buttonholing the posterior lamella. The
alleviate the ocular surface and prevent the fatty tissue and irregular areas.The graft is sutured to the lid margin skin
the extrusion of keratoprosthesis. mucosal graft is harvested and thinned and to the bulbar conjunctiva with a
without buttonholing, as buttonholed running double-armed 8-0 nylon suture.
PREREQUISITE areas may cause tearing of the graft The sutures are tied externally over
or serve as a nidus for keratinization bolsters medially and laterally. The entire
Prerequisite for successful postoperatively. The harvested graft is tarsus should be covered by the mucosa
autologous mucosal grafting is adequate –Š‡ ‘”‹‡–‡† ‘ ƒ –‘‰—‡ „Žƒ†‡ Ȁ ϐŽƒ– ‘ˆ to avoid phimosis or keratinization.
suppression of the underlying ocular –Š‡ ϐ‹‰‡”ǡ ”‹•‡† ™‹–Š ƒ–‹„‹‘–‹…ǡ ‡’– A layer of Amniotic membrane graft
•—”ˆƒ…‡ ‹ϐŽƒƒ–‹‘Ǥ Š‡ ’”‘…‡†—”‡ ‹• moistened until sutured at the recipient is placed over the cornea and tucked
usually unsuccessful during the acute site. beneath the MMG. This was followed by
phase of a cicatricial conjunctivitis with the placement of a symblepharon ring to
ƒ…–‹˜‡ ƒ† •‡˜‡”‡ ‹ϐŽƒƒ–‹‘Ǥ SPLIT THICKNESS GRAFT prevent the recurrence of symblepharon,
and a temporary tarsorrhaphy to achieve
PREPARATION OF THE DONOR SITE With a Castroviejo mucotome some pressure effect on the MMG by the
PRIOR TO ITS HARVESTING (setting at 0.3mm), a small split-skin knife symblepharon ring.
(e.g. Silver), or disposable dermatome,
Preoperative evaluation of the lip mucus membrane is cut. Š‡ —•‡ ‘ˆ ϐ‹„”‹ ‰Ž—‡ ȋ ‹••‡‡Žǡ ƒš–‡”Ȍ
—…‘•ƒ –‘ …‘ϐ‹” ‹–• ‰‘‘† Š‡ƒŽ–Š ȋ’‹ǡ for sticking the mucous membrane

www. dos-times.org 31

OCULAR SURFACE

Figure 1: 2TGQRGTCVKXG
5VGXGPŏU ,QJPUQPU 5[PFTQOG Figure 2: Post-operative photograph showing mucous membrane graft
QXGT VJG DWNDCT EQPLWPEVKXC NGCFKPI VQ FGETGCUGF KPƀCOOCVKQP CPF
decreased vascularisation.

Figure 3: #PQVJGT ECUG QH 5,5 UJQYKPI
UKIPKſECPV NKF MGTCVKPKUCVKQP
2TG QRGTCVKXG

reduces the intra-operative time and also Figure 4: Post-operative photograph showing Mucous membrane graft over lid margins.
eliminates the need for suturing along
the inner edge, which itself can cause a Post operatively, patient is to be OUR RESULTS OF MMG
considerable amount of surface irritation covered with systemic antibiotics.
in these patients. ‘—–Š™ƒ•Š‡•ǡ ƒ–‹•‡’–‹… ‰‡Žǡ ϐŽ—‹†• ƒ† ƒ Our experience with MMG has
soft diet may be required initially, but the been in a wide variety of ocular surface
For fornix reconstruction, the host wound heals rapidly. conditions.
–ƒ”•ƒŽ …‘Œ—…–‹˜ƒ ‹• ϐ‹”•– ”‡‘˜‡† —’
to the mucocutaneous junction, and CORNEAL STATUS SHOULD BE Especially gratifying has been its
any adhesion to the globe is released by MONITORED use in Subacute / Chronic SJS. In all 20
blunt dissection. The freshly harvested eyes done for this condition so far, it
oral mucosa is placed on the denuded Liberal topical tear substitutes has helped to restore and maintain the
–ƒ”•ƒŽ ’Žƒ–‡ ƒ† ϐ‹„”‹ –‹••—‡ ƒ†Š‡•‹˜‡ with corticosteroids and prophylactic anatomical structure and function of
can be used to attach the mucosal graft to antibiotic ointments are used on the the damaged ocular surface. It provides
the tarsus. Gentle ironing with a muscle ocular surface.The conformer is usually symptom alleviation in the form of relief
Š‘‘ ‡•—”‡• ƒ ϐŽƒ– —…‘•ƒŽ •—”ˆƒ…‡ ™‹–Š left in place for a week or 2, until the oral from pain and photophobia. Figure 1
proper adhesion. And a fornix formation mucosal graft heals and adheres properly. shows preoperative photograph of a 15
suture is put. A symblepharon conformer year old suffering from Stevens Johnsons
‹• ’Žƒ…‡† –‘ ƒ‹–ƒ‹ ˆ‘”‹š …‘ϐ‹‰—”ƒ–‹‘ COMPLICATIONS Syndrome (Subacute Stage). Figure 2
and discourage graft shrinkage. Finally, shows radical improvement post Mucous
a suture tarsorrhaphy is used to Ȉ ‡…—””‡…‡ ‘ˆ –”‹…Š‹ƒ–‹… Žƒ•Š‡• ‡„”ƒ‡ ‰”ƒˆ–‹‰ ™‹–Š •‹‰‹ϐ‹…ƒ–
immobilize the eyelids and stabilize the Ȉ •—”ˆƒ…‡ ‡”ƒ–‹‹œƒ–‹‘ lessening of the symptoms.
graft postoperatively9. Ȉ „Ž‡’Šƒ”‘’–‘•‹•
Ȉ ”‡…—””‡…‡ ‘ˆ †‹•‡ƒ•‡ ƒˆ–‡” •—”‰‡”› It also prevents crossover of the
LID MARGIN KERATINIZATION Ȉ ’‡”•‹•–‡– ‡’‹–Š‡Ž‹ƒŽ †‡ˆ‡…–• ‘” keratinized epithelium, thus acting as a
barrier.This is proved by the stopping
The keratinized lid margin is marked corneal ulceration, short of the keratinized area adjacent to
and dissected with the tarsal conjunctiva Ȉ ’‘‘” ‡›‡Ž‹† …Ž‘•—”‡ the transplanted mucous membrane as
ƒ• ƒ ϐŽƒ’Ǥ ‘‘” ƒ”‡ƒ †‹••‡…–‹‘ ‹• †‘‡ Ȉ Ž‹† Š›’‡•–Š‡•‹ƒ was observed by us in 7 eyes as shown
similar to described above. The harvested Ȉ ”‡…—””‡…‡ ‘ˆ •›„Ž‡’Šƒ”‘ ƒ† in Figure 3 (Preoperative) and Figure 4
graft is freed of any underlying fatty Ȉ •Ž‘—‰Š‹‰ ‘ˆ –Š‡ ‰”ƒˆ– (Postoperative).
tissue by sharp dissection and thinned
out to the extent possible to allow Poor results after mucous membrane MMG served to protect against
good stretchabilty of the graft. This is grafting seen in the most dangerous complication of
thenstretched and stuck over the tarsus Ȉ ‡˜‡”‡ ‡”ƒ–‘…‘Œ—…–‹˜‹–‹• •‹……ƒǡ Keratoprosthesis, i.e melt and subsequent
™‹–Š ”‡…‘•–‹–—–‡† ‰Ž—‡Ǥ ˆ–‡” …‘ϐ‹”‹‰ Ȉ ’”‘ˆ‘—† •…ƒ””‹‰ǡ ‘” leak. In more than 50 eyes we have done,
‰‘‘† ƒ’’‘•‹–‹‘ǡ –Š‡ …‘Œ—…–‹˜ƒŽ ϐŽƒ’ ™ƒ• Ȉ ƒ…–‹˜‡ ƒ† ‡†‹…ƒŽŽ› —…‘–”‘ŽŽ‡† it provides not only a resistant layer
excised off. preventing the underlying graft from
‹ϐŽƒƒ–‹‘ dessication related problems, but also

32 DOS TIMES - JANUARY- FEBRUARY 2017

OCULAR SURFACE

Figure 5: Showing mucous membrane graft as a protective layer over keratoprosthesis. mucosal transplantation in severe mucus
†‡ϐ‹…‹‡…› •—›†”‘‡•Ǥ ”Ǥ
Ǥ ’Š–ŠƒŽ‘ŽǤ
served to replenish the ocular surface REFERENCES 2000;84:279–84.
wetting to some extent. Figure 5 shows 3. Mai C, Bertelmann E. Oral Mucosal grafts:
4 years post operative photograph of 1. Henderson H, Collin J. Mucous Old technique in new light. Ophthalmic
one of our cases (with Severe dry eye membrane grafting. In: Geerling G, Res 2013;50:91–98.
preoperatively) maintaining well with Brewitt H, editors. Surgery for the Dry 4. Iyer G, Pillai VS, Srinivasan B, Guruswami
6/18 vision. Eye. Dev Ophthalmology. Basel, Karger S, Padmanabhan P: Mucous membrane
2008;41:230–42. grafting for lid margin keratinization in
Stevens Johnson syndrome (SJS). Cornea
2. Wenkel H, Rummelt V, Naumann G. Long 2010; 29: 146-51.
term results after autologous nasal 5. Gomes JA, Santos MS, Ventura AS, et al.
Amniotic membrane with livingrelated
corneal limbal/conjunctival allograft for
ocular surface reconstructionin Stevens-
Johnson syndrome. Arch Ophthalmol.
2003;121:1369–374.
6. Cher I. Blink-related microtrauma: when
the ocular surface harms itself. Clin
Experiment Ophthalmol. 2003;31:183–
90.
7. Wang S,Tian Y, Zhu H,Cheng Y, Zheng X,
Wu J. Tenonplasty combined with free
oral buccal mucosa autografts for repair
of sclerocorneal melt caused by chemical
burns. Cornea 2015; 34: 1240-44.
8. Forbes J, Collin R, Dart J. Split thickness
buccal mucous membrane grafts
ƒ† Ⱦ ‹””ƒ†‹ƒ–‹‘ ‹ –Š‡ –”‡ƒ–‡– ‘ˆ
recurrent pterygium. Br. J. Ophthalmol.
1998;82:1420–423.
9. Kheirkhah A, Blanco G, Casas V, Hyashida
Y, Raju V, Tseng S. Surgical Strategies
for fornix reconstruction based on
symblepharon severity. Am J Ophthalmol
2008;146: 266 –75.

Financial Interest: Š‡ ƒ—–Š‘”• †‘ ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ

www. dos-times.org 33

OCULAR MICROBIOLOGY

OCULAR INFECTIONS: MICROBIOLOGICAL
PERSPECTIVE

Nishat Hussain Ahmed, Gita Satapathy

Infectious diseases of the eye-like other infections are of major concern in India. Each
‹ˆ‡…–‹‘ ”‡“—‹”‡• •’‡…‹ϐ‹… ƒ† –‹‡Ž› ƒƒ‰‡‡– ˆ‘” „‡––‡” ‘—–…‘‡ǡ ˆ‘” ™Š‹…Š
early diagnosis is vital. This review focuses on the understanding of ocular defence
mechanisms; and pathogenesis, manifestations and diagnostic approaches of different
ocular infections as an aid to their better management.

Owing to the climatic conditions and other socio- 2. Ž‹ ”‡ϔŽ‡šǣ ›‡ Žƒ•Š‡• ‹‹–‹ƒ–‡ –Š‡ „Ž‹ ”‡ϐŽ‡š –‘ ’”‘–‡…–
economic factors, infectious diseases of the against airborne particles or trauma. Tactile stimulation
eye-like other infections are of major concern ‘ˆ …‘”‡ƒŽ •—”ˆƒ…‡ ƒŽ•‘ ‹‹–‹ƒ–‡• –Š‡ „Ž‹ ”‡ϐŽ‡šǤ Š‡ Ž‹†•
in India. Ocular infections can be self limiting- sweep over the anterior surface of the globe directing tears,
requiring only symptomatic treatment; debris, microbes, and allergens to the lacrimal excretory
some may be mild- treatable with empirical system.
ƒ–‹‹…”‘„‹ƒŽ•Ǣ ‘–Š‡”• ƒ› ”‡“—‹”‡ •’‡…‹ϐ‹… ‹˜‡•–‹‰ƒ–‹‘
directed antimicrobials; and there may be some which are sight- 3. †‹‰‡‘—• ‘…—Žƒ” ϔŽ‘”ƒǣ A number of micro-organisms
threatening infections and require aggressive intervention and ˆ‘” –Š‡ ‘”ƒŽ ϐŽ‘”ƒ ‘ˆ –Š‡ ‡›‡Ǥ Š‡› …‘’‡–‡ ™‹–Š –Š‡
systemic antimicrobial therapy. It is estimated that by the year pathogens for space and nutrients, thus do not allow
2020, the blind population in India will rise to 15 million and infection to occur.
ocular infections will account for 15% percent of the total
burden1,2. 4. ‡ˆ‡…‡• ‘ˆ –Š‡ –‡ƒ” ϔ‹Žǣ Š‡ –‡ƒ” ϐ‹Ž ‹• …‘’”‹•‡† ‘ˆ
Infections may occur on the surface of the eye, within three layers: lipid, aqueous, and mucous. These layers are
the globe of the eye or in the structures surrounding the eye. produced by the meibomian glands, the lacrimal glands, and
The etiological agents can be bacteria, mycobacteria, fungi, the goblet cells of the conjunctiva, respectively (Figure-1).
viruses or parasites and each of these produce a spectrum of ‡ƒ” ϐŽ‘™ ‡…Šƒ‹…ƒŽŽ› „ƒ–Š‡• –Š‡ ƒ–‡”‹‘” •—”ˆƒ…‡ ‘ˆ –Š‡
manifestations3. The prevalence and distribution of type of eye, preventing the adherence of microorganisms, and
infectious agents associated with eye vary widely and depend ϐŽ—•Š‡• ƒŽŽ‡”‰‡• ƒ† ˆ‘”‡‹‰ ’ƒ”–‹…Ž‡• ‹–‘ –Š‡ Žƒ…”‹ƒŽ
on variety of factors; therefore a proper etiological diagnosis ‡š…”‡–‘”› •›•–‡Ǥ Š‡ —…‘—• Žƒ›‡” ‘ˆ –Š‡ –‡ƒ” ϐ‹Ž ‡–”ƒ’•
performed with combination of characteristic clinical features foreign material, which facilitates its removal. The aqueous
and microbiological investigations is mandatory for successful layer contains several immunologically active substances
clinical outcome. –Šƒ– ’ƒ”–‹…‹’ƒ–‡ ‹ „‘–Š ‰‡‡”ƒŽ ƒ† •’‡…‹ϐ‹… ‘…—Žƒ” †‡ˆ‡…‡
A thorough knowledge of ocular defence mechanisms, (Table-1). Lipids secreted by the meibomian glands
various etiological agents, pathogenesis of manifestations, and ƒ‹–ƒ‹ –Š‡ •–ƒ„‹Ž‹–› ‘ˆ –Š‡ –‡ƒ” ϐ‹ŽǤ
the diagnostic approach goes a long way in managing patients
with eye infections. 5. Conjunctival defence: The protective epithelium of the
conjunctiva is made up of non-keratinized squamous

OCULAR DEFENCE MECHANISMS Figure 1: .C[GTU QH VJG VGCT ſNO

Eyes are armed with mechanical and immunological
functions for defence against a hostile environment. The
†‡ˆ‡…‡ ‡…Šƒ‹•• …ƒ „‡ ‰‡‡”ƒŽ‹œ‡† ‘” •’‡…‹ϐ‹… –‘ ’”‘–‡…–
the eye from invading microorganisms. For infection to occur,
some form of breach in ocular defence is mandatory. Important
components of ocular defence are:4
1. Anatomic defence: The eye balls are positioned in the bony

orbit which gives protection from three sides. Eyelids and
eyelashes also provide mechanical protection of the ocular
surface.

www. dos-times.org 35

OCULAR MICROBIOLOGY

Table 1: Components of human tears and their functions ROUTES OF INFECTION AND RISK
FACTORS OF INFECTION
Component Function
Ocular infections can occur from any
Lactoferrin Protein synthesized by the lacrimal gland; bacteriostatic action of the following routes:
on bacteria 1. Through the surface of the eye
2. Through hematogenous spread of
Lysozyme Bactericidal for gram-positive bacteria
infection
ȾǦ ›•‹ Bactericidal for bacteria 3. Through spread of infection from

Ceruloplasmin ‡‰—Žƒ–‡• –‹••—‡ †ƒƒ‰‡ ‹ ‹ϐŽƒƒ–‹‘ adjacent structures
Clearly, a normal healthy eye
Complement Phagocytosis, cell recruitment, bacterial lysis cannot get infected. Risk factors for
ocular infections include the factors
Immunoglobulins IgA, IgG, IgM and IgE. IgA is most abundant responsible for blood borne infections,
infections of nearby structures or those
ƒ„Ž‡ ʹǣ ‹…”‘„‹ƒŽ ϐŽ‘”ƒ ‘ˆ ‘”ƒŽ …‘Œ—…–‹˜ƒ which interfere with the ocular defence
mechanisms (Table-3).
Aerobic Bacteria Anaerobic Bacteria
SITES OF INFECTION
Gram Positive Propionibacterium sp.
Staphylococcus epidermidis Peptostreptococcus Infections may occur on the surface
Staphylococcus aureus Bacteroides sp. of the eye, within the globe of the eye or
Micrococcus sp. Lactobacillus sp. in the anatomical structures surrounding
Streptococcus pyogenes Clostridium sp the eye. The infection is often not limited
Streptococcus pneumoniae –‘ ƒ †‡ϐ‹‡† –‹••—‡ǡ –Š—• –Š‡”‡ ƒ”‡ ‹ˆ‡…–‹˜‡
Streptococcus viridans conditions like kerato-conjunctivitis,
Diphtheroids chorio-retinitis, iridocyclitis and pan-
ophthalmitis
Gram Negative Fungus
Moraxella catarrhalis Microbial conjunctivitis
ƒ‡‘’Š‹Ž—• ‹ϔŽ—‡œƒ‡ These are transient and are those found
Klebsiella sp. in the environment Conjunctivitis is by far the
Escherichia coli Viruses And Parasites commonest ophthalmic infection affecting
Pseudomonas aeruginosa people of all ages and in all geographic
Proteus sp. These are not normal residents of
Nil fermenting gram negative bacilli conjunctiva

epithelium, beneath which lies a present throughout the life. A very Table 3: Risk factors for ocular
vascular network and lymphoid small percentage of population have infections
structures. The conjunctiva sterile conjunctival sac. Staphylococci,
associated lymphoid tissue consists Streptococci and diphtheroids are Factors interfering with ocular
of both B and T lymphocytes5. predominant organisms. Anaerobic defence
6. Corneal defence: The cornea is bacteria are often present. 3 -15% of
exquisitely sensitive and even trivial population at a given time have fungal Trauma
stimulation of corneal surface elicits ϐŽ‘”ƒǤ Š‡•‡ ƒ”‡ –”ƒ•‹‡– ƒ† ƒ”‡ –Š‘•‡ Ophthalmic Surgery
ƒ •–”‘‰ „Ž‹ ”‡ϐŽ‡šǤ –ƒ…– ‘Ǧ found in the environment. New borns Dry eye
keratinized squamous epithelium have Escherichia coli and Staphylococci Ž–‡”‡† „Ž‹ ”‡ϐŽ‡š
acts as mechanical barrier. Cornea ƒ• ”‡•‹†‡– ‹…”‘„‹ƒŽ ϐŽ‘”ƒǡ ƒ• –Š‡ ƒ‰‡ Contact lens wear
is avascular and possesses limited advances, diphtheroids replace the Broad spectrum antibiotics
immune defenses. The two main coliforms. Gram negative bacilli are found Topical steroids
components are the Langerhans more often in hospitalised patients; in Traditional eye remedies
cells, which modulate B and T particular Pseudomonas sp., Proteus sp., Cosmetics
lymphocyte activity in the cornea; Alcaligenes faecalis and non-fermenting Prolonged systemic illness
and immunoglobulins, which are gram negative bacilli7 (Table-2). Factors causing blood stream
concentrated in the corneal stroma. infections
The corneal surface is covered by a Š‡ ”‘Ž‡ ‘ˆ ”‡•‹†‡– ‹…”‘„‹ƒŽ ϐŽ‘”ƒ Bacteremia
glycocalyx associated with a layer of in preventing eye infections is explicit. Fungemia
mucous glycoprotein. A subtype of ‘™Ž‡†‰‡ ‘ˆ ‹†‹‰‡‘—• ϐŽ‘”ƒ ‘ˆ Viremia
the IgA cross-links with the mucous conjunctiva is essential also to correctly Systemic parasitic infections
glycoprotein to cover and protect the interpret the observations of microscopy Systemic tuberculosis
anterior surface of the cornea6. and culture of conjunctival swabs. Parenteral nutrition
Sometimes resident bacteria can grow Central line
NORMAL FLORA OF THE in culture and may even be seen in the Infections of nearby structures
primary microscopy, when the cause of Infection of paranasal sinuses
CONJUNCTIVA ‘…—Žƒ” ‹ϐŽƒƒ–‹‘ ƒ› ƒ…–—ƒŽŽ› „‡ ‘Ǧ Infection of meninges
infectious or of viral or parasitic etiology! Dermatophytosis/ herpes of
‹…”‘„‹ƒŽ ϐŽ‘”ƒ ‹• ’”‡•‡– ‹ –Š‡ adjacent skin
conjunctival sac from birth and is

36 DOS TIMES - JANUARY- FEBRUARY 2017

OCULAR MICROBIOLOGY

Table 4: Common microbial agents causing keratitis Although various fungal agents
can be recovered from the conjunctiva,
Bacteria Viruses fungal conjunctivitis is rarely observed
clinically. In comparison with fungal
Gram-Positive Cocci Herpes simplex virus keratitis, relatively few organisms have
Staphylococcus aureus Varicella-zoster virus been implicated in fungal conjunctivitis.
Staphylococcus epidermidis Adenovirus Candida spp., Blastomyces spp., and
Streptococcus pneumonia Enteroviruses Sporothrix schenckii have been associated
Streptococcus pyogenes Coxsackievirus with a granulomatous conjunctivitis.
viridans streptococci
Enterococcus spp. Fungi Symptoms of conjunctivitis include
Peptostreptococcus spp. foreign body sensation, increased ocular
Gram-Positive Bacilli Fusarium spp. secretions, swelling of the conjunctiva
Corynebacterium diphtheriae Candida spp. and/or eyelids, light sensitivity and
Clostridium spp. Aspergillus spp. itching (mostly in fungal conjunctivitis).
Bacillus spp. Acremonium spp. Bacterial conjunctivitis involves rapid
Gram-Negative Cocci/Coccobacilli Alternaria spp. onset of unilateral lid edema, conjunctival
Neisseria gonorrhoeae Penicillium spp. injection, a mucopurulent discharge, and
Moraxella spp. Bipolaris spp. involvement of the second eye within
Acinetobacter spp. 1 to 2 days. Clinical presentation of
Gram-Negative Bacilli Parasites viral conjunctivitis is acute, unilateral
Pseudomonas aeruginosa, conjunctivitis with involvement of the
Escherichia coli Acanthamoeba spp. second eye occurring often within 1
Klebsiella spp. Microsporidia week. It is associated with a watery to
Proteus spp. Onchocerca volvulus mucous discharge and enlargement of
Serratia marcescens Leishmania brasiliensis pre-auricular lymph nodes.
Mycobacteria Trypanosoma spp
Mycobacterium tuberculosis Microbial Keratitis
Non-Tuberculous Mycobacteria
Spirochetes Microbial keratitis is a potentially
Treponema pallidum vision threatening infection of the cornea
Chlamydia which may be caused by bacteria, fungi,
Chlamydia trachomatis viruses or parasites. Ocular surface
homes a number of micro-organisms,
locations. Microbial conjunctivitis due to transmission from the mother all of which can cause keratitis in
‹˜‘Ž˜‡• ‹ˆ‡…–‹˜‡ ‹ϐŽƒƒ–‹‘ ‘ˆ –Š‡ during childbirth of sexually transmitted an environment favourable for that
thin lining of the inner eyelid and front of bacteria, including Neisseria gonorrhoeae particular organism. Etiological agents
the eyeball, caused by bacteria, viruses, and Chlamydia trachomatis. vary with the geographical region,
fungi, or parasites8. Risk factors include patient factors and other external factors
contact lens wear, contaminated ocular The most common cause of viral including trauma and medical/surgical/
medications, exposure to an infected conjunctivitis which occurs in epidemic diagnostic interventions. Disease burden
person, vaginal versus caesarean delivery, forms is infection with adenovirus and is higher in developing than in developed
and visits to camps and swimming pools. picornaviruses EV70 and coxsackievirus countries. The organisms commonly
Bacterial conjunctivitis is more prevalent A-24. But other viral causes include causing keratitis are enlisted in table-413.
in children; viral conjunctivitis is more herpes simplex virus (HSV) and herpes
prevalent in adults9-11. zoster virus11,12. Symptoms include severe pain
and discomfort, increased secretions,
Common causes of bacterial Parasites may be associated with photophobia, blepharospasm, and
conjunctivitis include Streptococcus conjunctivitis either by primary infection decreased vision. Eye pain is almost always
pneumoniae, Neisseria gonorrhoeae, orsecondarilyasaresponsetothepresence there due the rich innervations of corneal
Staphylococcus aureus, Haemophilus spp, of the parasite. Blepharoconjunctivitis is tissue. Clinical presentation includes
Moraxella, Corynebacterium diphtheriae, caused by Leishmania. Other parasites conjunctival injection and discharge,
and enteric gram-negative bacilli. implicated in causing conjunctivitis decreased corneal transparency, corneal
Neonatal conjunctivitis is commonly are ‘ƒ Ž‘ƒǡ ‹”‘ϔ‹Žƒ”‹ƒ, Microsporidia, ‹ϐ‹Ž–”ƒ–‡ǡ ‡’‹–Š‡Ž‹ƒŽ †‡ˆ‡…– ƒ†Ȁ‘” •–”‘ƒŽ
Cryptosporidium spp. etc. ‹ϐŽƒƒ–‹‘ǡ …‘”‡ƒŽ ‡†‡ƒǡ …‘”‡ƒŽ
neovascularization, stromal melting and

Ocular Microbiology Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences,All India Institute of Medical Sciences, New Delhi, India

Dr. Nishat Hussain Ahmed MD Dr. Gita Satapathy MD
Assistant Professor of Microbiology Professor of Microbiology

www. dos-times.org 37

OCULAR MICROBIOLOGY

Table 5: Causative agents of infections of lacrimal system caused by sinusitis, but rare cases follow
penetrating trauma, orbital surgery,
Infective manifestation Causative Pathogen canalicular surgery, peribulbar anesthesia
for eye surgery, endophthalmitis, dental
Dacryoadenitis S. aureus, Streptococcus pneumoniae, abscess, dacryocystitis, or dacryoadenitis.
ƒ‡‘’Š‹Ž—• ‹ϔŽ—‡œƒ‡ The orbit is delimited anteriorly by
orbital septum, which prevents spread
Canaliculitis Actinomyces ȋϐ‹Žƒ‡–‘—• „ƒ…–‡”‹ƒȌǡ of infection from the eyelids into orbit.
Staphylococci, Streptococci  ‹ϐŽƒƒ–‹‘ …‘ϐ‹‡† –‘ –Š‡ •’ƒ…‡
anterior to the orbital septum is called
Dacryocystitis Staphylococci, Streptococci, gram negative pre-septal cellulitis and that involving the
bacilli, few fungi soft tissues contained in the bony orbit is
called post-septal cellulitis. In pre-septal
Table 6: Causative agents of common adnexal infections cellulitis, swelling of eyelids is quite
remarkable; however it is having a good
Infective manifestation Causative Pathogen prognosis. In post-septal cellulitis, the
manifestations are proptosis, visual loss,
Blepharitis Staphylococci, Malessezia furfur (fungus), ophthalmoplegia and sensory loss along
Dermatophytes (fungi, as an extension of facial the distribution of trigeminal nerve. This
lesions) condition is met with poor visual outcome
and is also associated with high fatality
Hordeolum Staphylococcus aureus due to complications like cavernous
sinus thrombophlebitis and intracranial
Meibomitis Staphylococci, Streptococci spread25-27.

loss of vision. clinically evident in case of endogenous Common etiological agents of orbital
Keratitis in contact lens wearers: endophthlamitis. cellulitis are S. aureus, Streptococcus
pyogenes, S. pneumoniae, Haemophilus
Daily wearing of contact lenses for long Most cases of post procedural ‹ϔŽ—‡œƒ‡ǡ gram-negative bacilli and
hours predisposes a person for microbial endophthalmitis are caused by gram anaerobes. Mixed infections are common.
keratitis. Wearing of contact lenses causes positive cocci. Staphylococci, Streptococci In diabetic and ketoacidotic, neutropenic
relative hypoxia of corneal epithelium and Propionibacteria being the and other immunosuppressed patients,
and changes in cell surface glycocalyx. commonest. Pathogenic agents of post- fungal orbital cellulitis occurs due to
Microscopic defects are introduced in traumatic endophthalmitis also include Rhizopus, Mucor and Aspergillus.
the cornea by lens wear which provides a Haemophilus and Bacillus. Aspergillus
niche for adherence of the microbes. The and Fusarium are the most common Adnexal infections
most common organisms causing keratitis fungal pathogens causing exogenous
in contact lens wearers are Pseudomonas, endophthalmitis16-19. Infections of the ocular adnexa
Acanthamoeba and Candida; the former are largely related to the eyelids. The
two especially due to their ability to Endogenous endophthalmitis is infection of the skin of eyelids is called
grow in lens solutions, and the latter usually associated with Staphylococcal blepharitis28. Meibomitis is the infection
‘‡ †—‡ –‘ ˆ‘”ƒ–‹‘ ‘ˆ „‹‘ϐ‹Ž• ‘ –Š‡ bacteremia or candidemia20-21. of the meibomian glands and hordeolum
surface of lens. The infective keratitis is is the infection of sebaceous gland of the
commoner in soft contact lens wearers Panophthalmitis is Infection of all lid. Common pathogens causing adnexal
as compared to the semi-soft ones owing the contents of the globe. Usual pathogens infections are listed in Table-6.
to the hygroscopic nature of the former14. are gram negative bacteria, especially
Many of the infections can be prevented if Pseudomonas, gram positive bacteria Post procedural infections
the patient is careful in handling, cleaning including Staphylococci and Clostridia and
and storage of lenses15. fungi. With the advent of more and more
ophthalmic conditions becoming treatable
Endophthalmitis and Lacrimal system infections using various surgical procedures and
other invasive interventions, more
panophthalmitis By far, the commonest infection cases of post procedural infections
of lacrimal system is dacryocystitis, are occurring. The most common
Of the infections of globe of the which is the infection of lacrimal sacs. amongst these are endophthalmitis
eye, endophthalmitis is most common Other infections of the lacrimal system and graft infections. Most cases of post
and dreaded owing to the pace with are rare, they include dacryoadenitis, procedural endophthalmitis are caused
which it leads to loss of vision. Infective which is the infection of lacrimal gland by gram positive cocci. Infectious keratitis
endophthalmitis is a microbial infection and canaliculitis which is the infection following corneal transplantation is
inside the eye, involving the vitreous of superior or/and inferior canaliculi. one of the leading causes of failure of a
and/or aqueous. It is either exogenous, Manifestations of dacryocyctitis are corneal graft, especially in developing
in which infection is introduced from the discharge from eyes, swelling and redness countries. Staphylococcus epidermidis
outside, or endogenous, in which the eye at the medial canthus. On pressing the is the most common pathogen in
is seeded from the bloodstream. medial canthus, there is regurgitation corneal graft infection in the developing
of pus from the lacrimal punctum22-24. world, whereas Pneumococcus spp. and
Clinically the patients present with Table 5 shows the etiological agents of
decreased vision and eye pain. There is infections of lacrimal system.
usually a history of trauma, surgery or
intra-ocular injection in case of exogenous Orbital cellulitis
endophthalmitis. Manifestations of
systemic infection may or may not be Cellulitis is infection of the soft
tissue surrounding the orbit. It is usually

38 DOS TIMES - JANUARY- FEBRUARY 2017

OCULAR MICROBIOLOGY

Staphylococcus aureus are the commonest Table 7: Sample collection in various ocular infections
in the developed countries29-32.
Type of Type of Sample Recommended Device/
MICROBIOLOGICAL DIAGNOSIS Infection Procedure

It is important to have a precise Blepheritis Scales/Discharge from lid Forceps/Cotton swab
microbiological diagnosis of ocular margin
infections for initiating correct treatment
in time. Sometimes clinical features Cilia Forceps
provide a clue to the possible etiological
agents; however it is often not possible Conjunctivitis Fluid/Discharge –lower Calcium alginate/cotton swab
due to overlap of clinical features in conjunctival swab
manifestations of different infections.
Also there is always probability of Dacryocystitis Fluid/Discharge, lower Calcium alginate/cotton swab
mixed infections; and the patient being conjunctival swab
’ƒ”–‹ƒŽŽ› –”‡ƒ–‡†ǡ Ž‡ƒ†‹‰ –‘ ‘†‹ϐ‹‡†
manifestations and ambiguity in clinical Expressed pus Calcium alginate/cotton swab
diagnosis.
Keratitis Corneal scraping Kimura spatula/ surgical blade
In vivo Diagnosis: Confocal
Corneal biopsy Minor OT procedure
Microscopy
Corneal buttons Penetrating Keratoplasty-
It is a non-invasive technique surgical
for direct visualization of pathogen
throughout the entire depth of the cornea. Contact lenses, solution Aseptically removed and
It is especially useful for Acanthamoeba collected
and fungal keratitis. The sensitivity and
•’‡…‹ϐ‹…‹–› ‘ˆ …‘ˆ‘…ƒŽ ‹…”‘•…‘’› ˆ‘” Uveitis –‡”‹‘” …Šƒ„‡” ϐŽ—‹† Paracentesis
diagnosing infective keratitis is 88.3% and
91% respectively. Various studies have Orbital cellulitis Pus/aspirate Calciumalginate /cotton swab,
reported good inter and intra-observer syringe and needle
agreements for diagnosing keratitis.
It is particularly useful when corneal Nasal Discharge/ crust Calcium alginate /cotton swab,
‹ϐ‹Ž–”ƒ–‡ ‹• †‡‡’ •‡ƒ–‡†ǡ ‹ ™Š‹…Š …ƒ•‡ forceps
‹– ‹• †‹ˆϐ‹…—Ž– –‘ ‘„–ƒ‹ ƒ ‰‘‘† •ƒ’Ž‡ ˆ‘”
microscopy and culture. It can be used to Black eschar from hard Calcium alginate /cotton swab,
monitor the patients’ response based on palate forceps
density of organisms before and after the
treatment. However there are limitations Biopsy from the necrotised Minor OT procedure
in its widespread use as it requires the tissue
expensive machine and expertise in
confocal microscopy. Moreover, it cannot Endophthalmitis –‡”‹‘” …Šƒ„‡” ϐŽ—‹† Paracentesis
be used for infections other than those of
cornea33. Vitreous aspirate Paracentesis

Laboratory Diagnosis Vitreous biopsy Vitrectomy

As in other infectious diseases, an Intra-ocular lens Surgical removal
understanding of proper collection and
transport of specimen from the site of Blood for culture Venous tap
infection is of paramount importance
in case of ocular infections. Additional Panophthalmitis Vitreous biopsy Vitrectomy
vigilance is required in ocular specimens
as the quantity of specimen is very Evisceration contents Evisceration
minute and in many infections the load
of organisms is extremely less. Because where patient-side inoculation is not Microscopy
direct microscopic examination may be possible Amies transport medium without
useful in preliminary diagnosis of the charcoal may be used for transport and Primary smear examination of the
infection, whenever swabs are collected, storage for 24 h at room temperature35. clinical samples helps in initiation of
it is recommended to obtain dual swabs, Specimens for viral cultures should be •’‡…‹ϐ‹… –”‡ƒ–‡– ‡ƒ”Ž› ‹ –Š‡ †‹•‡ƒ•‡Ǥ
one for culture and one for smear submitted on ice, especially if specimen Gram stain is the most commonly used
preparation. Patient-side inoculation of transport is prolonged. Most samples, stain that demonstrates the presence of
culture media and preparation of slides ‡š…‡’– ϐŽ—‹†•ǡ ˆ‘” ’‘Ž›‡”ƒ•‡ …Šƒ‹ „ƒ…–‡”‹ƒ ƒ† ˆ—‰‹Ǥ ‘” ‹†‡–‹ϐ‹…ƒ–‹‘ ‘ˆ
is advised wherever feasible34. At places reaction (PCR) are placed in sterile fungal infection, potassium hydroxide
phosphate buffered saline pH 7.2 and ƒ† …ƒŽ…‘ϐŽ—‘” ™Š‹–‡ ‘—–• ƒ”‡ —•‡†Ǥ
submitted to the laboratory. Aqueous ‹‡ŠŽ ‡‡Ž•‡ •–ƒ‹‹‰ ƒ† ‘†‹ϐ‹‡†
ƒ† ˜‹–”‡‘—• ϐŽ—‹†• …ƒ „‡ †‹”‡…–Ž› —•‡† Ziehl Neelsen stains are used for
for DNA isolation for PCR. Table-7 shows identifying Mycobacteria and Nocardia
a compilation of appropriate specimens respectively. Special stains like Giemsa,
collected in different ocular infections. haemotoxylin-eosin etc. are used for
The modalities used for microbiological •’‡…‹ϐ‹… ‹†‹…ƒ–‹‘•Ǥ ƒ„Ž‡Ǧͺ •Š‘™•
diagnosis include microscopy, culture and various primary microscopy techniques
molecular methods. Immunodiagnostic used for diagnosing eye infections.
methods are seldom used in ocular
infections, however some indications stay Culture: conventional/automated
put.
Culture remains the gold standard
for diagnosing bacterial and fungal

www. dos-times.org 39

OCULAR MICROBIOLOGY

Table 8: Primary microscopy techniques used for diagnosing eye infections in the form of E-test; it combines the
simplicity of disc diffusion test with the
Suspected organism Primary microscopy technique ability to determine MICs.

Bacteria Gram stain Susceptibility testing against
antifungal drugs can be performed for
Mycobacteria Zeihl Neelsen’s (ZN) staining ›‡ƒ•–• ƒ† ϐ‹Žƒ‡–‘—• ˆ—‰‹ „› „”‘–Š
or agar dilution methods, where MIC is
Nocardia ‘†‹ϐ‹‡† •–ƒ‹‹‰ ȋ†‡…‘Ž‘”‹œ‡” ͳΨ 2SO4 ) determined; or by disc diffusion method.
Fungi Potassium hydroxide mount Disc diffusion method similar to bacterial
disc diffusion is available for yeasts and
‘–ƒ••‹— Š›†”‘š‹†‡ ‘—– Ϊ ƒŽ…‘ϐŽ‘—” ™Š‹–‡ ϐŽ—‘”‡•…‡…‡ •‘‡ ϐ‹Žƒ‡–‘—• ˆ—‰‹Ǥ ”—‰• …‘‘Ž›
stain –‡•–‡† ‹…Ž—†‡ ͷ ȋϐŽ—…›–‘•‹‡Ȍǡ
‡–‘…‘ƒœ‘Ž‡ǡ ‹…‘ƒœ‘Ž‡ǡ ϐŽ—…‘ƒœ‘Ž‡ǡ
Potassium hydroxide mount + Lacto phenol cotton blue dye itraconazole, and Amphotericin B.
However routine testing of fungal isolates
Gram stain for susceptibility to antifungal drugs is
not done by most laboratories.
Periodic Acid Schiff
b. Automated culture
Gomori Methanamine Silver
Automated culture systems use one
Giemsa or more of different parameters including
turbidity, concentration and gradients
Parasites Wet mount ‘ˆ ‰ƒ•‡•ǡ ’”‡••—”‡ …Šƒ‰‡•ǡ ϐŽ—‘”‡•…‡…‡
Acanthamoeba Giemsa and metabolic products etc. to detect the
growth of microorganisms in the medium.
Microsporidia ‘†‹ϐ‹‡† •–ƒ‹‹‰ ȋ ‹›‘—ǯ• ‘†‹ϐ‹…ƒ–‹‘Ȍ If growth is detected, a signal is produced
in positive specimens; the organism is
Trichrome staining ‹†‡–‹ϐ‹‡† ‹ ϐŽƒ‰‰‡† •’‡…‹‡• —•‹‰
colony morphology, microscopy and
Chlamydia Giemsa (for inclusion bodies) bio-chemicals. Automated systems for
different panels of bio-chemicals can
Viruses Giemsa (for inclusion bodies) „‡ —•‡† ˆ‘” ‹†‡–‹ϐ‹…ƒ–‹‘ ‘ˆ ’ƒ–Š‘‰‡•Ǥ
Similarly, panels for antimicrobial
infections. Culture is also the standard a temperature of 25–27 °C and a BOD susceptibility can be used for automated
method for diagnosis of Acanthamoeba. detection of susceptibility pattern of
For Microsporidia, Chlamydia and incubator. Fungal cultures are incubated organisms. Automated culture and
viruses tissue culture is done; however detection systems are more popular for
it is not used routinely for patient care for at least two weeks before a specimen bacterial pathogens. They have advantage
purposes. Maintaining the requirement ‘ˆ ‡ƒ”Ž› †‡–‡…–‹‘ ƒ† ‹†‡–‹ϐ‹…ƒ–‹‘ǡ ƒ•
of patient side inoculation of culture is considered negative. compared to manual interpretations in
media depending on the suspected conventional methods; also, as manual
etiological agent is obligatory to obtain Acanthamoeba cultures are maneuvering is less, the chances of
good culture results. Culture can be done errors are less if procedures are correctly
in conventional manner or with the help incubated at 37 °C for two weeks. followed. However, as with any other
of automated machines. automated system calibrations need
Interpretation of cultures: Aerobic to be done timely and any unusual or
a. Conventional culture ƒ„‹‰—‘—• ”‡•—Ž–• ‡‡† –‘ „‡ …‘ϐ‹”‡†
bacterial cultures are interpreted based by conventional methods.
Culture media: For bacterial
cultures, standard media used are blood on colony morphology, microscopy, Molecular Methods
agar and brain heart infusion broths. If
fastidious bacteria (e.g. Haemophilus) motility and biochemical reactions. Molecular methods, especially
are suspected, additional inoculation on polymerase chain reaction (PCR), are
chocolate agar is required. Sabouraud’s Anaerobic bacterial cultures are also ‡š–”‡‡Ž› •‡•‹–‹˜‡ ƒ† •’‡…‹ϐ‹…Ǣ ƒ†
dextrose agar is used for fungal cultures, are sought-after for diagnosing ocular
and non-nutrient agar with Escherichia •‹‹Žƒ”Ž› ‹†‡–‹ϐ‹‡†Ǥ ‘” ‹†‡–‹ϐ‹…ƒ–‹‘ ‘ˆ infections. PCR is particularly useful in
coli overlay is used for Acanthamoeba diagnosing infections due to organisms
culture. true anaerobes aerobic challenge is given –Šƒ– ƒ”‡ †‹ˆϐ‹…—Ž– –‘ …—Ž–—”‡ •—…Š ƒ•
viruses, Microsporidia, Chlamydia etc.;
Incubation conditions: For to all the isolates of anaerobic cultures. or those that take long time to grow, such
aerobic bacterial cultures, all media are as Mycobacterium tuberculosis. PCR is
incubated at 37 °C for 48 to 72 hours. —‰ƒŽ …—Ž–—”‡• ƒ”‡ ‹†‡–‹ϐ‹‡† „ƒ•‡† also considered to be useful in cases of
Some laboratories incubate for up-to 5 endophthalmitis, where the sensitivity of
days before giving a negative report of on their gross morphology and pigment;
aerobic bacterial cultures. Chocolate agar
is incubated in 3–5% CO2 in a candle jar and microscopic morphology as seen in
or CO2 incubator. For anaerobic bacterial
cultures, anaerobic chamber or anaerobic LPCB mounts or slide cultures.
jar with gas pack is required. Anaerobic
cultures are incubated at least for 5 days Acanthamoeba cultures are
before discarding.
interpreted based on daily observation
Sabouraud’s dextrose agar requires
of the cultures under the microscope

to look for presence of Acanthamoeba

trophozoites and cysts.

Antimicrobial susceptibility

testing36: With rising antimicrobial

resistance, susceptibility testing is a

must at least for all bacterial pathogens.

It helps in determining the most effective

drug that can be used for treatment.

Susceptibility of bacteria to antibiotics

is standardized by clinical laboratory

standards institute (CLSI), and is updated

yearly. The guidelines are available

for disc diffusion assay as well as for

determination of minimum inhibitory

concentrations (MIC). A simple method of

MIC determination has become available

40 DOS TIMES - JANUARY- FEBRUARY 2017

OCULAR MICROBIOLOGY

microscopy and culture is very low due to Little, Brown and Company, New York, Endogenous endophthalmitis: an 18-
less organism load in the lesion. Recently, USA. 1996. year review of culture-positive cases
the utility of PCR in diagnosing fungal 7. Sthapit PR, Tuladhar NR. Conjunctival at a tertiary care center. Medicine.
infections accurately and in less time has Flora of Normal HumanEye. JSM 2003;82:97-105.
also been demonstrated. Ophthalmol 2014:2:1021. 22. Boruchoff SA, Boruchoff SE. Infections
8. O’Brien TP, Jeng BH, McDonald M, of the lacrimal system. Infect Dis Clin
ƒ”‹‘—• ‘†‹ϐ‹…ƒ–‹‘• ‘ˆ ‹ –Š‡ Raizman MB. Acute conjunctivitis: North Am. 1992;6:925-932.
form of real time PCRs and multiplex truth and misconceptions. Curr Med 23. Chaudhry IA, Shamsi FA, Al-Rashed W.
PCRs are also being developed for ocular Res Opin. 2009:25:1953-61. Bacteriology of chronic dacryocystitis
infections. 9. van der Weele GM, Rietveld RP, in a tertiary eye care center. Ophthal
Wiersma T, Goudswaard AN. [Summary Plast Reconstr Surg. 2005;21:207-210.
Immunodiagnostic methods of the practice guideline “The red eye” 24. Freedman JR, Markert MS, Cohen
ȋϐ‹”•– ”‡˜‹•‹‘Ȍ ‘ˆ –Š‡ —–…Š ‘ŽŽ‡‰‡ AJ. Primary and secondary lacrimal
Immunodiagnostic methods are not of General Practitioners (NHG)]. Ned canaliculitis: a review of literature.
a component of mainstay diagnosis of Tijdschr Geneeskd. 2007;151:1232-7. Surv Ophthalmol. 2011;56:336-347.
ocular infections. However, at some places 10. Golde KT, Gardiner MF. Bacterial 25. Jain A, Rubin PAD. Orbital cellulitis
they are indicated and have practical use. conjunctivitis in children: a current in children. Int Ophthalmol Clin.
review of pathogens and treatment. Int 2001;41:71-86.
Detection of Chlamydia antigen by Ophthalmol Clin. 2011:51:85-92. 26. Brook I, Frazier EH. Microbiology
‹—‘ǦϐŽ—‘”‡•…‡…‡ ‹ …‘Œ—…–‹˜ƒŽ 11. Langston DP. Viral diseases of the of subperiosteal orbital abscess
swabs and that of herpes simplex virus cornea and external eye, in: Albert DM, and associated maxillary sinusitis.
(HSV) in corneal scrapings is very useful. Miller JW, eds; Azar DT, Blodi BA, assoc Laryngoscope. 1996;106:1010-1013.
Antibody detection is also sometimes eds. Albert and Jakobiec’s Principles 27. Seltz LB, Smith J, Durairaj VD, et
helpful in ocular manifestations and Practice in Ophthalmology. 3rd ed. al. Microbiology and antibiotic
of systemic diseases like syphilis, Philadelphia: Saunders. 2008:813-27. management of orbital cellulitis.
toxoplasmosis etc. 12. Asbell P. Viral conjunctivitis. In: Pediatrics.2011;127:e566-e572.
Hyndiuk RA, Tabbara KF,eds. Infections 28. Raskin EM, Speaker MG, Laibson PR.
CONCLUSION of the Eye. Boston: Little, Brown; Blepharitis. Infect Dis Clin North Am.
1996:453-70. 1992;6:777-787.
Managing ocular infections is 13. Barnes SD, Hallak J, Langston DP, Azar 29. Merchant A, Zacks CM, Wilhelmus K,
teamwork. It requires skillful use of DT. Microbial Keratitis. In: Mandell, et al. Candidal endophthalmitis after
the clues obtained from clinical and Douglas, and Bennett’s Principles and keratoplasty. Cornea. 2001;20:226-
ophthalmic examination of the patient Practice of Infectious Diseases. eds. 229.
for identifying the appropriate specimen Principles and Practice of Infectious 30. Day S, Acquah K, Mruthyunjaya P, et
to be collected at appropriate time and Diseases. 8th ed.Vol.-1, Elsevier al. Ocular complications after anti-
using required precautions. Following Saunders, Philadelphia; 2015:1402 vascular endothelial growth factor
that, the most useful set of investigations 14. Stapleton F, Edwards K, Keay L, et al. therapy in Medicare patients with age-
are done in a state of the art manner with Risk factors for moderate and severe related macular degeneration. Retina.
due maintenance of turnaround time. microbial keratitis in daily wear 2011;31:2032-2035.
Investigation guided treatment is then contact lens users. Ophthalmology. 31. Narang S, Gupta A, Gupta V, et al.
provided to the patient and a complete 2012;119:1516-21. Fungal endophthalmitis following
follow up is done. 15. Butcko V, McMahon TT, Joslin CE, Jones cataract surgery: clinical presentation,
L. Microbial keratitis and the role of microbiological spectrum, and outcome.
REFERENCES rub and rinsing. Eye Contact Lens. Am Ophthalmol. 2001;132:609-617.
2007;33:421-23 32. Vajpayee RB1, Sharma N, Sinha R,
1. ThyleforsB,NégrelAD,Pararajasegaram 16. Lalwani GA, Flynn HW Jr, Scott IU, et Agarwal T, Singhvi A. Infectious
R, Dadzie KY. Available data on al. Acute-onset endophthalmitis after keratitis following keratoplasty. Surv
blindness (update 1994). Ophthalmic clear corneal cataract surgery (1996- Ophthalmol. 2007:52:1-12.
Epidemiol. 1995:2:5–39. 2005): clinical features, causative 33. Sharma S. Diagnosis of fungal keratitis:
organisms, and visual acuity outcomes. current options. Expert Opinion on
2. Thylefors B, Négrel AD, Ophthalmology. 2008;115:473-476. Medical Diagnostics. 2012:6: 449-55.
Pararajasegaram R, Dadzie KY. Global ͳ͹Ǥ ‹™ƒ”† ǡ ϐŽ—‰ˆ‡Ž†‡” ǡ 34. Baron EJ, Miller JM, Weinstein MP,
data on blindness. Bull. World Health Flynn HW Jr, et al. Postoperative Richter SS, Gilligan PH, Thomson
Organ. 1995:73:115–21. Propionibacterium endophthalmitis: Jr RB, et al. A Guide to Utilization
treatment strategies and long-term of the Microbiology Laboratory for
3. Sharma S. Diagnosis of infectious results. Ophthalmology. 1993;100:447- Diagnosis of Infectious Diseases: 2013
diseases of the eye. Eye. 2012:26:177– 51. Recommendations by the Infectious
84. 18. Thompson WS, Rubsamen PE, Flynn Diseases Society of America (IDSA) and
HW Jr, et al. Endophthalmitis after the American Society for Microbiology
4. Klotz SA, Penn CC, Negvesky GJ, Butrus penetrating ocular trauma: risk (ASM). Clinical Infectious Diseases.
SI. Fungal and Parasitic Infections of the factors and visual acuity outcomes. 2013.
Eye. Clin Microbiol Rev. 2000:13:662- Ophthalmology. 1995;102:1696-701. 35. McLeod SD, Kumar A, Cevallos V,
85 19. Miller JJ, Scott IU, Flynn HW Jr, Srinivasan M, Whitcher JP. Reliability
et al. Endophthalmitis caused by of transport medium in the laboratory
5. Chandler JW and Gillette TE. Bacillus species. Am J Ophthalmol. evaluation of corneal ulcers. Am J
Immunologic defense mechanism of 2008;145883-888. Ophthalmol 2005:140:1027–31
the ocular surface. Ophthalmology. 20. Jackson TL, Eykyn SJ, Graham EM, et al. 36. Clinical and Laboratory Standards
1983: 90:583–591. Endogenous bacterial endophthalmitis: Institute. Performance Standards
a 17-year prospective series and for Antimicrobial Susceptibility
6. Nassif KF. Ocular surface defense review of 267 reported cases. Surv Testing; Twenty Third Informational
mechanisms, in Infections of the eye. Ophthalmol. 2003;48:403-423. Supplement. CLSI document M100-S26;
21. Binder MI, Chua J, Kaiser PK, et al. 2016.

Financial Interest: Š‡ ƒ—–Š‘”• †‘ ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ
www. dos-times.org 41

MONTHLY MEETING KORNER

ASYMMETRIC OCULAR HYPERTENSION IN A YOUNG
ADULT - A DIAGNOSTIC CONUNDRUM

Dr. Narottama Sindhu MD, DNB, MNAMS His past ocular history has been eventful - History of
Visiting Glaucoma Consultant cracker injury OS 5 years back, eye was patched for a day and
Goyal Eye Institute, Patel Nagar. remained asymptomatic later; history of exposure to welding
EYE-Q, Shalimar Bagh. arc in July 2015 and had classical presentation of OU pain,
Shreya Eye Clinic, Naraina Vihar watering and photophobia appearing at night, on advice of
his classmates used some eye drop and was alright in a day’s
ANew Delhi –‹‡Ǣ Š‹•–‘”› ‘ˆ —•‡ ‘ˆ –Š‡ •ƒ‡ ‡›‡ †”‘’ ȋ ‹†‡–‹ϐ‹‡† ‹– –‘ „‡
young patient who was detected to have ocular Betnesol N e/d when shown various types of commonly used
Š›’‡”–‡•‹‘ǡ ƒ •›•–‡ƒ–‹… ƒ’’”‘ƒ…Š –‘ ϐ‹† ‘—– e/ds) for any ocular discomfort on and off since Aug/Sept 2015
its cause is discussed. which he stopped using since 17/12/2015 on advice of one of
the eye surgeon he had consulted previously. There has been no
CASE contributory past medical/treatment/family history of chronic
eye disease.
A 19 years old young patient, a mechanical
engineering student, presented with complaint On examination, systemically he was found to be in good
of blurring of vision in OS since Dec 2015. health. His detailed ocular examination revealed BCVA of 6/6p
Ž—””‹‰ ‘ˆ ˜‹•‹‘ ™ƒ• ‡’‹•‘†‹… ‹ ƒ–—”‡ǡ ϐ‹”•– –‹‡ ‘–‹…‡† OD, 6/6 OS with +1.25/+2.25x90° OD and +1.75/+1.00x90°OS.
when he was writing his exams and later while playing cricket Anterior segment examination was essentially normal with
under Sunlight. He would develop hazy vision within 5 minutes ‘”ƒŽ †‡’–ŠǤ ‹‰‹ϐ‹…ƒ– ”‡Ž‡˜ƒ– ‡‰ƒ–‹˜‡ ϐ‹†‹‰• ™‡”‡
of starting exam which would last throughout the exam period – No prominent Schwalbe’s line, no kruckenberg spindle, no
‘ˆ ͵ Š”• ƒ† ™‘—Ž† „‡…‘‡ ƒŽ”‹‰Š– ™‹–Š‹ ͷ ‹—–‡• ‘ˆ ϐ‹‹•Š‹‰ KP’s, no iris atrophy/trans illumination defects. Gonioscopic
exams – a very consistent pattern, never associated with pain, examination (Figures 1) revealed immaturity of angle in the
redness, watering, headache, coloured halos. For his complaints form of homogenous thinly pigmented trabecular meshwork,
he visited two different eye surgeons locally, both advised him prominent iris processes and anterior insertion of iris in
change of his glasses (he is a glass user for last 12 years) and both the eyes. Superior angle showed narrow entry with no
some tear substitutes. Thus he landed up changing his glasses evidence of previous irido-trabecular touch. OS gonioscopy did
twice in three months but there was no relief.

ab c

de a. Superior Angle (Narrow)
b. Superior Angle opening up on dynamic
Figure 1: Gonioscopy Findings
Gonioscopy
c. Temporal Angle showing high iris

insertion
d. Nasal Angle showing iris processes and

high iris insertion
e. Inferior Angle wide open

www. dos-times.org 43

MONTHLY MEETING KORNER

not reveal evidence of trauma. His IOP on Figure 2: Glaucoma Investigations – Fields/OCT
GAT was 30 mmHg and 38 mmHg in OD
& OS respectively (his previous record of DIFFERENTIAL DIAGNOSIS
04/01/2016 mentions digital pressure as
normal). His CCT was 591μ OD and 594μ Steroid Induced1,2 AGAINST
OS. He was found to have small discs, FOR
Š›’‡”ƒ‡‹… ™‹–Š ™‡ŽŽǦ†‡ϐ‹‡† ƒ”‰‹•
and 0.2 cupping with no RNLF defects Š H/o use of high potency steroid e/d Š Duration & frequency of use of steroid
either eyes. Š Associated risk factors in form of ‘– ˜‡”› …Ž‡ƒ” …—–Ǥ —ˆϐ‹…‹‡– ‡‘—‰Šǫǫ
possible compromised angles Š Not used steroids for last >3 months.
Underwent glaucoma investigations Š Goniodysgenesis OU Not a natural course?
and biometry. Glaucoma investigations Š H/o trauma OS, though no visible Š DTn mentioned as NORMAL e/w when
did not reveal any glaucomatous damage evidence. However, TM sclerosis off steroids for 2 weeks(4 Jan 2016)
(Figure 2); he was found to have small could still be contributing explaining
axial lengths explaining the narrowness asymmetric response.
of angles (Table1).
Pigment Dispersion Syndrome AGAINST
TREATMENT FOR

He was put on anti-glaucoma Š ›’‹…ƒŽ Š‹•–‘”› Ƭ ’ƒ–‹‡– ’”‘ϐ‹Ž‡ Š No corneal / Iris / Gonioscopic features.
medications in a step wise manner. Table Young, male, B/L involvement, becoming Š Not a myope
2a & Table 2b summarises his AGT. His symptomatic while playing under Sun
IOP in OS could be brought under control suggesting physical activity & warming
only for few months and again has shown up of body precipitating attack.
a rise in spite of him undergoing SLT along Š DTn Normal e/w points to episodic
with maximal AGM topically. His follow nature of IOP rise.
up examination shows progression in cup
size in OS (Figure 3). Hence he will have Primary Angle Closure Disease AGAINST
to be under taken for either goniotomy3 FOR
or trabeculectomy with Mitomycin C.
Š Hypermetrope Š The very h/o Vn being blurred under
DISCUSSION Š Narrow entry to superior angle is Sunlight (miosis) with no media opacity
clearly seen. r/o ACD
Interesting observations and take Š Gonioscopic narrowness may show Š Unlikely for angles to remain only
subjective variation depending upon the appositionally narrow with no other
home messages pressure exerted. organic changes for over 3 months time.

This case highlights how steroid Juvenile Ocular Hypertension1,4 AGAINST
induced ocular hypertension, not an FOR
uncommon occurrence, still gets easily
overlooked. Any young patient with Š Age <35yrs, B/L high IOP Š Patient became symptomatic while
high IOP one should keep in mind the Š DTn recorded normal e/w when 2 on steroids and continued so even after
possibility of steroid use in any form and weeks off steroids, so not a SI. withdrawing suggesting possible SI.
every effort should be made to elicit the Š Presence of Goniodysgenesis
history of steroid use as was done in this
case. Coexistent Juvenile OHT & Steroid Induced (Unmasking)

Steroid responders usually FOR
have associated risk factors locally/
systemically/family history of glaucoma. Š Became symptomatic while using potent steroid topically
Since this patient neither had family Š Not reverting back even on withdrawal of steroids
history of glaucoma nor any systemic Š Presence of compromised angles (Goniodysgenesis), a known risk factor for steroid
”‹• ˆƒ…–‘”•ǡ ‡’Šƒ•‹• ™ƒ• ’—– –‘ ϐ‹† responsiveness.
out the local risk factor/s. A thorough Š Šƒ”‡ ƒ …‘‘ ’ƒ–Š‘‡…Šƒ‹• ˆ‘” ”‹•‡ Ǧ Ž–‡”ƒ–‹‘ ‹Ǯ ›‘…‹Ž‹ǯ ȋ
Ȍ ‰‡‡
gonioscopy, examining all four quadrants, –Mutation/Upregulation
revealed goniodysgenesis. Examining
superior and inferior angles only, which is
most of the time done, would have missed
the evidence of goniodysgenesis.

The period of IOP control in OS was
found to coincide with his summer break
and sudden shot up in IOP coincided
with restarting of his exams. Recalling
that he used to get symptomatic in the
examination hall forces one to think if his
mental stress has any bearing on his IOP,
considering that he is a steroid responder.

44 DOS TIMES - JANUARY- FEBRUARY 2017

Figure 3: Follow-up Glaucoma Investigations MONTHLY MEETING KORNER

Parameter Table 1: Biometry Keeping this in mind, role of Alternative
AL (mm) Values medicine, especially meditation, may be
ACD (mm) 20.34 / 20.68 (Short AL and narrow angles) worth exploring in such patients.
LD (mm) 2.27 / 2.39
K (D) 3.75 / 4.11 REFERENCES
44.07 & 46.74 / 44.24 & 45.96
1. Sohn S, Hur W, Choi YR et al. Little
evidence for association of the
glaucomagene MYOC with open
angle glaucoma. Br J Ophthalmol
2010;94:639-42.

2. Jones R III, Dhee DJ. Corticosteroid-
induced ocular hypertension and
glaucoma: a brief review and update of
the literature. Curr Opin Ophthalmol.
2006;17:163-67.

3. Yeung HH1, Walton DS. Goniotomy
for juvenile open-angle glaucoma. J
Glaucoma. 2010;19:1-4.

4. Viney Gupta, Rajat M. Srivastava, Aparna
Rao, Manik Mittal, John Fingert. Clinical
correlates to the goniodysgensis
among juvenile-onset primary open-
angle glaucoma patients. Graefe’s
Archive for Clinical and Experimental
Ophthalmology. 2013;6:1571–76.

Table 2a: Anti-Glaucoma Treatment

Table 2b: Anti-Glaucoma Treatment (contd.)

Abbreviations: T=Timolol, B=Brimonidine,BiM=Bimataprost, Bx=Brinzolamide, Dz=Dorzolamide,
CAI= Carbonic Anhydrase Inhibitor
Financial Interest: Š‡ ƒ—–Š‘”• †‘ ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ
Case presentation in the DOS Monthly Clinical Meeting at Goyal Eye Institute, November 27, 2016.

www. dos-times.org 45

MONTHLY MEETING KORNER

IOFB VIA AN IMPROMPTU APPROACH

Dr.Anshul Goyal MBBS Figure 2: After Cataract Surgery
Goyal Eye Institute
East Patel Nagar, New Delhi

A55 year old male who was a goldsmith by
’”‘ˆ‡••‹‘ ”‡’‘”–‡† –‘ —• ˆ‘” –Š‡ ϐ‹”•– –‹‡ ƒ„‘—–
1 year ago. He presented with total cataract in
the right eye following trauma. As alleged, the
trauma was trivial in nature; patient stated that
while mending jewelry a metallic chip hit and
left the eye.

On Examination, He has a vision of perception of Hand
movement in the right eye and 6/6 in the left eye. A corneal
scar was noted in the infero-nasal quadrant.

Total white cataract was present. No Lens matter was seen
in the anterior chamber, and the entire visible anterior capsule
after dilatation was remarkably intact. The Left eye examination
was within normal limits.

B-Scan showed an attached retina, no IOFB was noted, and
few mobile dot echoes were noted inferiorly suggesting mild
vitreous hemorrhage.

The patient was taken up for cataract surgery (done 1
year ago). Capsulorrhexis was completed successfully. As

Figure 1: Infero-Nasal Corneal Scar Figure 3: : 4C[ %QPſTOKPI /GVVCNKE +1($
www. dos-times.org 47

MONTHLY MEETING KORNER

Figure 4: Sclerotomy enlarged to 20 Gauge and Figure 5: Mettalic IOFB at the posterior pole Figure 6: IOFB is circular in shape, least linear

beyond to deliver the IOFB free of all vitreous adhesions diameter is too large for Pars plana removal

Figure 7: IOFB brought into the Anterior Figure 8: IOFB kept over the PCIOL Figure 9: IOFB delivered via Limbal Section
Chamber through the PCR

posterior tilting of the lens nucleus was It was explained to the patient that this case as the PCR was diametrically
iron impurities in the IOFB were initiating opposite the right hand sclerotomy.
noticed at the start of sculpting, the case Siderosis Bulbi and it would be prudent
to remove the same. Limbal route for delivery of IOFB
was converted to ECCE, and nucleus was is a luxury that may not be available
The patient was taken up for 23 in all cases, however it is superior to
delivered completely. A Large PCR was gauge 3 port vitrectomy. The IOFB was pars plana route for several reasons.
located in the vitreous base at 6’0’clock. Enlarging the sclerotomy poses greater
noted nasally. After clearing vitreous from After clearing it from the engulfed risk of rupturing a uveal vessel that can
vitreous, it was brought to the posterior ”‡•—Ž– ‹ •‹‰‹ϐ‹…ƒ– „Ž‡‡†‹‰Ǥ Žƒ”‰‡”
anterior chamber, 1-piece IOL was placed pole. sclerotomy also increases the chances
of vitreous incarceration in it, and also
in the sulcus and the case was closed. The supero-temporal sclerotomy higher chances of vitreous traction from
was converted to 20 gauge opening and ϐ‹„‡”• ‡‰ƒ‰‡† ‹ –Š‡ ”ƒ‰‰‡† ‡†‰‡• ‘ˆ
The immediate post op period was further enlarged to deliver the IOFB. the IOFB at the time of delivery from the
As the IOFB was picked up from the sclerotomy.
uneventful. Fundus examination revealed posterior pole, it was realized that it is
Šƒ† ƒ ϐŽƒ– ƒ† …‹”…—Žƒ” •Šƒ’‡Ǥ Š‡ Ž‡ƒ•– Another issue associated with pars
mild vitreous hemorrhage inferiorly, linear diameter of the IOFB was too big ’Žƒƒ ”‘—–‡ ‹• Ž‡ƒ‹‰ ϐŽ—‹†‹…•Ǥ – –Š‡ –‹‡
for the enlarged sclerotomy. The large of enlarging the sclerotomy; the IOFB
retina was attached throughout, and no PCR was diametrically opposite to this lies in the vitreous cavity at the posterior
sclerotomy and the surgeon decided to pole. Picking the IOFB with forceps with
foreign body was noted. place the IOFB through this PCR into the a leaking sclerotomy can be tricky, as
anterior chamber on top of the IOL. ‘˜‡”ϐŽ‘™ ‘ˆ ‘ –‘ –Š‡ …‘”‡ƒ …ƒ
At 2 months follow up patient had impair the view, and also the distortion of
The IOFB was then delivered from the globe due to hypotony. Any posterior
regained a BCVA OF 6/6, N6 in his right the limbal route and the case was closed segment intervention if needed to be
successfully. The patient has been doing performed after delivering an IOFB
eye. well post operatively. through an enlarged sclerotomy, shall
require a fresh sclerotomy after closing
About 1 year after this surgery, DISCUSSION this one.

patient reported back with c/o discomfort The surgeon had the advantage of
approaching the anterior chamber in
and foreign body sensation in the operated

eye. He was maintaining a vision of 6/6, n6

with glasses in both eyes. On examination

an exposed 10-0 knot was noted and was

removed in the OPD. However on closer

‡šƒǡ Š‡ Šƒ† ͳΪ …‡ŽŽ• ƒ† ʹΪ ϐŽƒ”‡Ǥ —†—•

Examination showed mild vitritis,

old vitreous hemorrhage seen present

inferiorly was reduced in comparison to

last visit. A shiny object was seen through

this hemorrhage, suggesting an IOFB!

 šǦ”ƒ› ™ƒ• †‘‡ –‘ …‘ϐ‹” –Š‡

IOFB.

Financial Interest: Š‡ ƒ—–Š‘” †‘‡• ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ
Case presented in the DOS Monthly Clinical Meeting at Goyal Eye Institute, November 27, 2016.

48 DOS TIMES - JANUARY- FEBRUARY 2017

MONTHLY MEETING KORNER

MULTIFOCAL CHOROIDITIS- A CASE REPORT

Rahul Kumar Sharma, Abhishek Dagar, Anirban Tarafdar, Vivek Kumar

A25 year old female presented with blurring of Figure 1-4: Right eye color fundus photo showing active Multifocal
vision in right eye since 20 days, which was choroidal lesions and old scarred lesions
gradual in onset, painless and progressive in
nature in June 2016. No similar complaints in
past history. Family history revealed that her
husband was undergoing treatment of sputum
positive pulmonary tuberculosis since 1 month.

Patient was orthoporic, with best corrected visual acuity
of 6/18 (Log MAR 0.5) in right eye and 6/6 (LogMAR 1.0) in
Ž‡ˆ– ‡›‡Ǥ –‡”‹‘” •‡‰‡– ‘ˆ ”‹‰Š– ‡›‡ Šƒ† ͳΪ ‹ϐŽƒƒ–‘”›
cell (Standardization of uvietis nomenclature grading {SUN}).
Posterior segment had vitritis in right eye. Left eye was within
normal limits with no signs of uveitis. Both eyes applanation
tonometry was 16 mm of Hg.

Fundus examintaion in right eye (Figure 1,2) showed
—Ž–‹’Ž‡ „”‹‰Š– ›‡ŽŽ‘™ •—„”‡–‹ƒŽ Ž‡•‹‘• ™‹–Š ‹ŽŽǦ†‡ϐ‹‡†
borders over the posterior pole and up to the mid periphery
.Varying degrees of marginal pigmentation and scar formation
(Figure 3,4) seen in inferior mid periphery along second and
third order retinal blood vessels. Left eye fundus was normal
(Figure 5).

On laboratory investigations, erythrocyte sedimentation
rate (ESR) was 32mm/hour, Montoux skin test was positive
ȋʹͲšʹͲ Ȍǡ Š—ƒ ‹—‡ †‡ϐ‹…‹‡…› ˜‹”—• ȋ Ȍ ƒ†
Treponemal pallidum haemagglutination assay (TPHA) were
non-reactive. Serun ACE was 24 IU (normal). Quantiferon TB
gold test was positive. Chest Xray, HRCT Chest, USG whole
abdomen was normal. Sputum for acid fast bacilli was negative.
Patient denied for vitreous biopsy for Polymerase chain
reaction (PCR) to rule out tubercular antigen.

Optical coherence tomography at macula of right eye was
™‹–Š‹ ‘”ƒŽ Ž‹‹– ™‹–Š ‘ •‹‰• ‘ˆ ‡†‡ƒ ‘” •—„”‡–‹ƒŽ ϐŽ—‹†
(Figure 6).

—†—• ϐŽ—‘”‡•…‡‹ ƒ‰‹‘‰”ƒ’Š›ǣ ƒ”‡†
Š›’‡”ϐŽ—‘”‡•…‡…‡ •—””‘—†‹‰ –Š‡ Ž‡•‹‘• ‹ –Š‡ ‡ƒ”Ž› ’Šƒ•‡•
(Figure7), which increased in size and intensity over the mid
ƒ† Žƒ–‡ ’Šƒ•‡• •‹‹Žƒ” –‘ ”‹‰ ‘ˆ ϐ‹”‡ ȋ ‹‰—”‡ ͺȌ ƒ’’‡ƒ”ƒ…‡ ‹
choroidal tubercles were seen.

Š‡ ‹–”ƒŽ‡•‹‘ƒŽ Š›’‡”ϐŽ—‘”‡•…‡…‡ ‹…”‡ƒ•‡† ‰”ƒ†—ƒŽŽ›
over the mid and late phases (Figure 9) till, there was a
Š‘‘‰‡‘—• Š›’‡”ϐŽ—‘”‡•…‡…‡ ‹˜‘Ž˜‹‰ –Š‡ …Š‘”‘‹†ƒŽ Ž‡•‹‘Ǥ

™‘ †‹•–‹…– œ‘‡• ™‡”‡ ‹†‡–‹ϐ‹‡†ǣ ƒ ‘—–‡” œ‘‡ –Šƒ– ‹•
Š›’‡”ϐŽ—‘”‡•…‡– ‘˜‡” ƒŽŽ –Š‡ ’Šƒ•‡• ƒ† ƒ’’‡ƒ”• –‘ „‡ Ž‘…ƒ–‡†
in the surrounding (peritubercular) tissues and an inner initial
Š›’‘ϐŽ—‘”‡•…‡– Ȁ Žƒ–‡ Š›’‡”ϐŽ—‘”‡•…‡– œ‘‡ –Šƒ– …‘””‡•’‘†•
to the tubercle. Left eye angiogram was normal, no signs of
’ƒ–Š‘Ž‘‰‹…ƒŽ ϐŽ—‘”‡•…‡…‡ ȋ ‹‰—”‡ ͳͲȌǤ

ƒ•‡† ‘ Š‹•–‘”›ǡ …Ž‹‹…ƒŽ ϐ‹†‹‰ǡ Žƒ„‘”ƒ–‘”› ‹˜‡•–‹‰ƒ–‹‘
ƒ† ˆ—†—• ϐŽ—‘”‡•…‡‹ ƒ‰‹‘‰”ƒ’Š›ǡ ’ƒ–‹‡– ™ƒ• •–ƒ”–‡† ‘
antitubercular treatment (ATT) with oral steroid. Patient
responded to the treatment very well, vision improved to 6/6
(LogMAR1.0) in right eye and fundus examination showed
resolved vitritis and healed choroidal lesions (Figure11) with
no recurrence on follow up.

www. dos-times.org 49

MONTHLY MEETING KORNER

Figure 5: Left eye color fundus photo. Figure 6: Right eye optical coherence tomography.

Figure 7: Right eye FFA– Early phase Figure 8: 4KIJV G[G ((# /KF RJCUGŌ4KPI QH ſTG CRRGCTCPEG

Figure 9: Right eye - FFA Late phase Figure 10: Left eye FFA

Vitreo-Retina Services,Venu Eye institute & Research Center, Sheikh Sarai, New Delhi.

Dr. Rahul Kumar Sharma MS, FICO Dr.Abhishek Dagar MS, DNB Dr.Anirban Tarafdar DOMS, DNB, FICO Dr.Vivek Kumar DNB
50 DOS TIMES - JANUARY- FEBRUARY 2017

MONTHLY MEETING KORNER

Figure 11: Fundus photo Right eye showing healed choroidal tubercles after treatment. helps to differentiate between various
…Š‘”‘‹Ǧ”‡–‹ƒŽ Ž‡•‹‘•Ǥ —†—• ϐŽ—‘”‡•…‡‹
DIFFERENTIAL DIAGNOSIS (a) Retinal vasculitis, (b) pattern in the above case showed similar
ϐŽ—‘”‡•…‡…‡ ƒ• ’”‡˜‹‘—•Ž› †‘…—‡–‡†
Ȉ —Ž–‹ˆ‘…ƒŽ …Š‘”‘‹†‹–‹• ȋ•‡…‘†ƒ”› –‘ Serpiginous - like choroiditis (SLC) in literature in choroidal tubercles5,6, that
sarcoidosis) is, peritubercular tissues (outer zone)
and (c) Choroidal tubercles: Although •Š‘™• Š›’‡”ϐŽ—‘”‡•…‡…‡ ‘˜‡” ƒŽŽ –Š‡
Ȉ Š‹–‡ †‘– •›†”‘‡ ȋ ǡ phases whereas the tubercle (inner zone)
APMPPE, PIC, MC with PU) uncommon, are the most well-recognized •Š‘™• ƒ ‹‹–‹ƒŽ Š›’‘ϐŽ—”‡•…‡…‡ ƒ† Žƒ–‡
Š›’‡”ϐŽ—‘”‡•…‡…‡Ǥ ‘„‹‡† ’‹…–—”‡
Ȉ ‹”† •Š‘– Š‘”‹‘”‡–‹‘’ƒ–Š› manifestation. gives a “RING OF FIRE” appearance.
Ȉ ƒ•“—‡”ƒ†‡•ȋŽ›’Š‘ƒȌ
Choroidal tubercles, identical to Š‹• ƒ‰‹‘‰”ƒ’Š‹… ϐ‹†‹‰ …‘—Ž†
DISCUSSION be helpful in differentiating cases of
tubercles elsewhere in the body, were one choroidal tubercle from other forms of
Tuberculosis is a classic aerosol unilateral or bilateral choroiditis, further
infection, acquired through the lungs of the earliest signs described in miliary studies are needed to document similar
via the inhaled droplets carrying the ƒ‰‹‘‰”ƒ’Š‹… ϐ‹†‹‰Ǥ
tubercular bacilli1. tuberculosis4. Most commonly situated in
The literature regarding the
Although the primary focus of the posterior pole, these can be solitary angiographic features of the smaller
infection is usually the lung, it can involve and medium-sized tubercular lesions
various organs, including the eye. The eye or multiple in number, unilateral or is limited. Laghmari and associates
is involved secondary to haematogenous commented on the angiographic features
spread from the primary complex or the bilateral. Mild anterior chamber reaction, of the tubercles in an 11-year-old with
secondary lesions where the organisms military tuberculosis and phlyctenular
may remain latent for a long time2. vitritis, periphlebitis may be present. keratoconjunctivitis. They noted an early
Š›’‘ϐŽ—‘”‡•…‡…‡ ƒ† Žƒ–‡ ‘†‡”ƒ–‡
Over the years, the clinical Evidence of tubercular uveitis can Š›’‡”ϐŽ—‘”‡•…‡…‡7. The presence of
spectrum of tubercular uveitis has ocular TB may be subtle, and a high index
widened and includes anterior uveitis be indirect or direct. Indirect evidence of suspicion is critical in endemic areas
typically presenting as granulomatous because misdiagnosis of ocular TB can
uveitis with or without iris nodules or is based on the clinical indicators have irreversible visual consequences.
uncommonly as nongranulomatous
‹ϐŽƒƒ–‹‘ǡ ‹–‡”‡†‹ƒ–‡ —˜‡‹–‹•ǡ ȋ‰”ƒ—Ž‘ƒ–‘—• ‹ϐŽƒƒ–‹‘ǡ The Mantoux test and PCR from
ciliary body tuberculoma, and posterior ‘…—Žƒ” ϐŽ—‹†• ‹• …—””‡–Ž› –Š‡ ‡–Š‘†
uveitis commonly in the form of choroidal intermediate uveitis, choroidal tubercles of choice for detection of latent TB
tubercle or tuberculoma, retinal vasculitis, infections. The dramatic response to
serpiginous-like choroiditis and rarely or tuberculoma, serpiginouslike antituberculour therapy in combination
as neuroretinitis, endophthalmitis, or ™‹–Š …‘”–‹…‘•–‡”‘‹†• Œ—•–‹ϐ‹‡• ‡’‹”‹…ƒŽ
panophthalmitis3. choroiditis, retinal vasculitis), a treatment based on a high index of clinical
suspicion and positive Mantoux test.
Posterior uveitis is the most common positive Tuberculin skin test (TST), and
presentation of intraocular TB, presents REFERENCES
as – radiological evidence of active or inactive
1. Dannenberg, Jr AM. Pathophysiology: Basic
extraocular TB. aspects. In Schlossberg D (Ed). Tuberculous
and Nontuberculous Mycobacterial
Direct evidence may be obtained infections. 4th edition. Philadelphia,WB
Saunders Company, 1999;17-47.
from ocular investigations. A positive
2. Massaro D, Katz S, Sachs M. Choroidal
polymerase chain reaction (PCR) or tubercles: A clue to hematogenous
tuberculosis. Ann Int Med 1964;60:231-41.
demonstration of the bacilli by Ziehl-
3. Gupta V, Gupta A, Rao NA. Intraocular
Neelsen staining or culture from ocular tuberculosis—an update. Surv Ophthalmol
07;52:561–587.
ϐŽ—‹†• ȋƒ“—‡‘—•ǡ ˜‹–”‡‘—•ǡ ‘” •—„”‡–‹ƒŽ
4. Helm CJ, Holland GN. Ocular tuberculosis.
ϐŽ—‹†Ȍ ‹• …‘ϐ‹”ƒ–‘”›Ǣ Š‘™‡˜‡”ǡ –Š‡ ›‹‡Ž† Surv Ophthalmol 1993;38:229 –56.

of AFB by smear and culture is typically 5. Gupta A, Sharma A; Expert Rev Ophthalmol.
2012;7:341-49.
poor from ocular specimens unless there
͸Ǥ ƒŽ‹Ž ‡Š–ƒǡ —†—• ϐŽ—‘”‡•…‡‹
is a clinical picture of endophthalmitis angiography of choroidal tubercles: Case
reports and review of literature, Indian J
with extensive caseation necrosis. Ophthalmol 2006;54:273-5.

—†—• ϐŽ—‘”‡•…‡‹ ƒ‰‹‘‰”ƒ’Š› 7. Laghmari A, Boutimzine N, Elmoussaif H,
Benjelloun A, Essakalli NH, Benabdallah
™‹–Š ‹–• ˜ƒ”‹‡† ’ƒ––‡” ‘ˆ ϐŽ—‘”‡•…‡…‡ N, et al. Bouchut’s tubercles. Clinical and
angiographic study, apropos of a case. J Fr
Ophtalmol 1997;20:383-6.

Financial Interest: Š‡ ƒ—–Š‘”• †‘ ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ
Guest case presented in the DOS Monthly Clinical Meeting at Centre For Sight, December 18, 2016.

www. dos-times.org 51

MONTHLY MEETING KORNER

SPECTACLE PRESCRIPTION IN CHILDREN:
UNDERSTANDING PREVALENT PRACTICE PATTERNS

Dr. Sumit Monga 0.5 Dcyl/180 degrees OU. The child had aligned eyes,
MS, DNB, FRCS (Glasg), FLVPEI (Hyderabad) normal anterior and posterior segments. What would you
Consultant, Pediatric, decide to do?
Strabismus and Neuro-ophthalmology Services,
Centre for Sight, Delhi NCR. 20% of the responders would prescribe according to
PMT, while 80% decided to manage the refractive error
Pediatric refraction has its own unique challenges, …‘•‡”˜ƒ–‹˜‡Ž›ǡ ƒ– ’”‡•‡–Ǥ Š‡ Žƒ––‡” •‡‡• Œ—•–‹ϐ‹‡† ‘ –Š‡ „ƒ•‹•
viz. low cooperation of children, variable of well, established principle of emmetropization, the process
retinoscopy readings, amblyopia risk etc. One where the change in dimensions of the eye in the early years of
other factor, which complicates the issue, is the life, effect in spontaneous regression of refractive errors. The
different interpretations of the same refractive American academy of pediatric ophthalmology and strabismus
errors, while prescribing in children, by the (AAPOS) has devised evidence based spectacle prescription
ophthalmologists. This article focusses on the latter issue. protocols for young children1 (Table 1). The bottom-line is
Since spectacles, for children, are prescribed universally by that refractive error needs to be prescribed in children, only if
all ophthalmologists, we thought it was best to take their amblyogenic enough.
viewpoint, to understand the prevalent practice patterns.
For the same, an online, anonymous survey questionnaire Q4: 5 yr. old; unaided vision of 6/18p in RE and
(https://www.surveymonkey.com/r/7NFQNV3) was sent 6/12p in LE. The child had aligned eyes (on torch light),
to AIOS members through email/social media. This ongoing movements are full, normal anterior and posterior
survey includes practical real life practical problems (10 brief segments. Cycloplegic refraction reveals +4.5/-1.0/180
questions), concerning pediatric refraction. Each question was degrees OU. PMT: +2.0/-0.5/180 OU (BCVA 6/12p OD, 6/9p
multiple choice type, with one of four responses to be chosen. OS).What would you do?
The survey assumes that reliable refraction, using appropriate
cycloplegics, has been done. The thrust was on decision making Majority (85%) would prescribe according to PMT
approach: when and how do you prescribe for children? Till the response, and 1/3rd (30%) would start additional occlusion
date of last compilation of data, 112 responses were obtained therapy for amblyopia, based on the documented asymmetric
(18th Dec 2016). The results of the survey are being shared visual responses. On a careful review of the situation, we
below, along with the discussion based on the concerned issue would realize that we are making lot of assumptions here.
in the published literature. This child actually requires a careful cover test evaluation
to rule subtle esophoria/esotropia, analysis to rule out any
Q1: What percentage of your practice are pediatric ϐ‹šƒ–‹‘ ’”‡ˆ‡”‡…‡ ƒ† ƒ••‡••‡– ‘ˆ „‹‘…—Žƒ”‹–›Ǥ ˆ –Š‡ …Š‹Ž†
patients (overall)? Šƒ† ƒ Žƒ–‡– ‘” ƒ‹ˆ‡•– ‡•‘†‡˜‹ƒ–‹‘ǡ ™‹–Š ‘‡ ‡›‡ ϐ‹šƒ–‹‘
preference (could be objectively assessed with vertical prism
It was interesting to note that almost 79% of the ϐ‹šƒ–‹‘ –‡•– ‘” ƒ ”‡•‹•–ƒ…‡ –‘ ‘……Ž—•‹‘ ‘ˆ –Š‡ ‰‘‘† ‡›‡ǡ ‹ …ƒ•‡
responders were multi-specialty ophthalmologists (pediatric of dense amblyopia) with decreased binocular response (as
clientele less than 40%). “The proportion of pediatric patients
seen” was taken as a criteria to understand the background www. dos-times.org 53
of the responding ophthalmologists, as the label of “pediatric
ophthalmology specialist” is vague in our country, due to lack of
government recognized super-specialty fellowship programs.

Q2: How are glasses, in children, prescribed at your set
up?

In most cases (53%), the refraction was done by
optometrists and prescribed by ophthalmologists.
Interestingly, just over 1/3rd (34%) ophthalmologists, still
did their own refractions and prescribe themselves. Only 7%
of the responders would refer a refractive error case to their
pediatric ophthalmologist colleague. The bottom-line is that
‘’Š–ŠƒŽ‘Ž‘‰‹•– ™ƒ• –Š‡ ϐ‹ƒŽ †‡…‹•‹‘ ƒ‡” ‹ •’‡…–ƒ…Ž‡
prescription in majority (94%) of cases.

Q3: 3 year old child cycloplegic refraction +1.5 Dsph/-

MONTHLY MEETING KORNER

Œ—†‰‡† „› ™‘”–Š Ͷ †‘– –‡•– ‘” –‹–—• ϐŽ› Atropine 1% for few weeks) along with anisohypermetropia) is another potent
stereovision test), then the child would bifocal spectacles for temporary use. stimulus for amblyopia. In case of
full cycloplegic correction, irrespective With the increasing use of screen based anisometropia, even the cutoff for
of child’s responses. If the child is indeed devices for long hours, this entity is surely spectacle prescription (as per the
orthophoric for distance and near, on showing an increasingly trend. AAPOS guidelines)are lower than for
…‘˜‡” –‡•–•ǡ ™‹–Š ‘ ϐ‹šƒ–‹‘ ’”‡ˆ‡”‡…‡ symmetrical, isometropic refractive
and good stereo acuity, the child would Question 6: 6 yr. old girl; Unaided errors1. Also, there are objective methods
require spectacles after fogging on PMT vision 6/36 OU; Aligned eyes, to evaluate amblyopia (like the vertical
(undercorrect hyperopia ny 1.5- 2.0 unremarkable anterior and posterior ’”‹• ϐ‹šƒ–‹‘ –‡•–ǡ —•‹‰ ͳͶ „ƒ•‡
D). The child may also require initial segments. Cycloplegic refraction: +5.0 down loose prism) in preverbal children.
cycloplegics for initial adaptation to Dsph/-4.5 D cyl/180 degrees OU. PMT One need not necessarily wait for child’s
glasses. As a corollary, high hyperopes : +2.0 Dsph/-2.5 D cyl/180 degrees visual responses alone; otherwise the
(6D) also require full correction, due to OU (BCVA 6/18p OU). Which of the unwarranted delay would lead to dense
their amblyopia potential. The learning following prescriptions would you amblyopia, which would be tough to
’‡ƒ”Ž ‹• –Šƒ– ˆ‘” •‹‰‹ϐ‹…ƒ– Š›’‡”‘’‹… agree with? tackle at a higher age.
refractive errors, in addition to the visual
responses, also appropriately evaluate Results: PMT + Alternate eye Q8: How do you monitor a child
accommodation, alignment status, patching (34%); +4.0 D sph/-4.5 with refractive errors?
ϐ‹šƒ–‹‘ ’”‡ˆ‡”‡…‡ ƒ† „‹‘…—Žƒ”‹–›ǡ Dcyl/180 (6/18 OU) (35%); +3.5 Dsh/-
and then prescribe accordingly2. In case 3.5 Dcyl/180 (6/18 pOU) (12%); +2.0 It was gratifying to see that
the same are not assessable in your Dsh/-3.5 Dcyl/180 (6/18 ppOU) (19%) overwhelming 99.9% monitor cases of
setup, the help of a trained pediatric refractive error, at follow up visits, with
ophthalmologist should be taken (though Essentially, the debate here is visual acuity, alignment evaluation and by
only 13% had indicated in the survey that between undercorrected astigmatism checking their stereovision. If its’ indeed
they would do so, for such a situation). (65%) vs. full corrected astigmatic the case, it is an ideal situation and would
prescription (35%). It is imperative to help defeat the scourge of amblyopia.
Q5: 8 yr. old comes with blurred understand that astigmatism (>2 D) is a
vision OU since one week. Unaided potent stimulus for amblyopia, as unlike Q 9: Who decides about the
vision 6/36 in RE, 6/18p in LE. Dry spherical errors, it is not neutralized material and design of spectacles, in a
acceptance: RE -5.5 Dsph (6/18p); enough, by accommodation. Hence, child?
LE -3.5 Dsph (6/12p). Anterior and unless we fully correct both meridians
posterior segments are unremarkable; in astigmatism, we won’t be able to It was heartening to learn that
Aligned eyes (torch light); Cycloplegic achieve the amelioration of amblyopia4. almost 2/3rd of the responders (64%),
refraction show +0.25 Dsph OU. What Interestingly, children are easily receptive participated in the spectacle making
would you do next? to high astigmatic errors (upto 4.5 to 5.0 process, by indicating the nature of
D), compared to adults, probably because lenses and frame, to be made. In fact, all
„‘—– ƒ ϐ‹ˆ–Š ȋʹͳΨȌ ‹†‹…ƒ–‡† –Š‡‹” children with such refractive errors prescribing ophthalmologists should
preference to prescribe the myopia, are already amblyopic to begin with. If have a working knowledge about the
while almost half (48%) indicated the child has symmetrical meridonial same. Glass lenses are avoided in children,
their preference to re-refact the child ƒ„Ž›‘’‹ƒ ȋ‘ ’”‡ˆ‡”‡–‹ƒŽ ϐ‹šƒ–‹‘Ȍǡ due to their obvious traumatic potential.
under Atropine 1%. Just less than 1/3rd they tend catch up over time with CR39 lenses are the universally preferred.
(31%) opined for using cycloplegics and just appropriate spectacles (alternate In case of one eye status of a child or a
transient bifocals in such a case. patching may not be required). Needless •’‡…‹ϐ‹… ”‡“—‹”‡‡– ˆ‘” ‡›‡ ’”‘–‡…–‹‘
to say, that the cases with high astigmatic (e.g. contact sports), polycarbonate lenses
To understand this situation, we errors, also need to be evaluated to rule are preferred (although they are costlier).
should recollect the physiological process out corneal ectasia. Large aperture frames are preferable to
of accommodation. In the latter, when avoid looking “over or under the frame”.
the ciliary muscles contract, the lens Question 7: 2 year old boy with ’’”‘’”‹ƒ–‡ ϐ‹––‹‰ ƒ† ‘’–‹…ƒŽ …‡–”ƒ–‹‘
becomes more convex, thus shortening pseudo strabismus. Cycloplegic is extremely important in children,
its focal length and we are able to refraction (Atropine 1 %) :OD especially for astigmatism. Adjustable
focus on near objects. In the event of a +4.5 Dsph; OS +1.5 D sph. Anterior nose pads and elastic self-retainers (head
persistent ciliary spasm, the increasing and posterior segments were bands) may be used. Rimless frames need
convexity of lens would remain and unremarkable. What would you do? to be avoided in children (again especially
there would be induced myopia. This for astigmatism). Special situations
accommodative spasm would lead to About 1/3rd (35%) opted for ”‡“—‹”‡ ‘†‹ϐ‹…ƒ–‹‘•ǡ ‡Ǥ‰Ǥ •‡ ‘ˆ Š‹‰Š
pseudo-myopia, leading to blurring of conservative management (Would wait index lenses for high refractive errors,
vision for distance. Always consider this either for child up with a reliable visual use of bifocal lenses in a case of high
entity in a case of recent onset blurriness response, or would prescribe only if squint AC/A ratio, use of tinted lenses in cone
of vision with documented myopia with develops or would just watch for stability dystrophies, etc.
•‹‰‹ϐ‹…ƒ– †‹•’ƒ”‹–› ‹ †”› ƒ† ™‡– of refraction over next year). While the
refractions3. Careful evaluation may also others would go ahead and prescribe, ͳͲǣ Š‡ •Š‘—Ž† –Š‡ ϐ‹”•–
reveal subtle esodeviation and miosis, in evaluate for possible amblyopia and start screening of refractive errors be done,
•‘‡ …ƒ•‡•Ǥ Š‡•‡ …ƒ•‡• ‹†‡‡† „‡‡ϐ‹– occlusion. in an asymptomatic child?
with cycloplegic therapy (often require
It needs to be understood 60% of the respondents, favour an
that anisometropia (especially

54 DOS TIMES - JANUARY- FEBRUARY 2017

MONTHLY MEETING KORNER

age based refractive error screening (23 metropolitan setting like Delhi, if the or patience for examining all the details in
% would prefer at 6 months, while 37 % government can make a refractive error a child, please feel free to refer the child to
™‘—Ž† •…”‡‡ ƒ– ͵ ›”• ‘ˆ ƒ‰‡ȌǤ •‹‰‹ϐ‹…ƒ– •…”‡‡‹‰ …‡”–‹ϐ‹…ƒ–‡ ƒ†ƒ–‘”› ȋ„› ƒ a trained pediatric ophthalmologist. After
group (40%) would screen for refractive “—ƒŽ‹ϐ‹‡† …‡”–‹ϐ‹‡† ‘’Š–ŠƒŽ‘Ž‘‰‹•–Ȍ ǡ ˆ‘” ƒ all, it is our moral obligation to ensure
errors only when child is able to give a child of 3 yr. old child, who is just joining that future generation of tomorrow is
verbal response or if strabismus develops. school. Needless to say, in the interim, amblyopia free.
that the whole ophthalmic community
Š‡ „‡‡ϐ‹–• ‘ˆ ˜‹•‹‘ •…”‡‡‹‰ ƒ– and medical professionals should keep on REFERENCES
an early age, has been well recognized5. striving to keep on spreading awareness
However, many debate that a vision about early screening of refractive error 1. Miller JM, Harvey EM. Spectacle
screening module tends to pick up in young children. prescribing recommendations of
children with only moderate or high AAPOS members. J Pediatr Ophthalmol
refractive errors. To add to it, the lack of The take home message is that for Strabismus 1998; 35:51-2.
standard vision screening protocols and before prescribing any refractive error in
the lack of a consensus on a “safe” vision a child, in addition to the visual response 2. Associations between Hyperopia and
cut off, make the process vulnerable. (subjective), the objective parameters other Vision and Refractive Error
Therefore, many researchers have raised Ž‹‡ ‡›‡ ƒŽ‹‰‡–ǡ ϐ‹šƒ–‹‘ ’”‡ˆ‡”‡…‡ǡ Characteristics. Optom Vis Sci. 2014;
the pitch for a combined refractive error accommodative response, stereo acuity 91: 383–389.
screening at a young age. An integrated and overall visual need of the patient
approach is obviously better5. However, (asthenopia relief, alignment restoration, 3. Goldstein J H etal. Spasm of the Near
it is easier said than done, as it needs amblyopia potential of the refractive ‡ϐŽ‡šǣ ’‡…–”— ‘ˆ ‘ƒŽ‹‡•Ǥ —”˜
trained personnel and resources, for error), should also be checked. And above Ophthalmol 1996;40:269-78.
an effective mass screening, which is all, do not forget passion and patience. In
lacking, at least, at present. Probably case any treating ophthalmologist feels 4. Sainani A. Special considerations for
a start can be made in a limited, urban that they do not have the time, energy, skill prescription of glasses in children. J
Clin Ophthalmol Res 2013; 1: 169-73.

5. Sharma A, Congdon N, Patel M,
Gilbert C School-based approaches to
the correction of refractive error in
children. Surv Ophthalmol 2012; 57:
272–83.

Financial Interest: Š‡ ƒ—–Š‘” †‘‡• ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ
Clinical Talk presented in the DOS Monthly Clinical Meeting at Centre For Sight, December 18, 2016.

For KIND ATTENTION OF ALL VOTING DOS MEMBERS

Ž‡ƒ•‡ ‡•—”‡ –Šƒ– ›‘—” …‘””‡…– ƒ††”‡•• ȋ ˆϐ‹…‡ ƒ† ‡•‹†‡–‹ƒŽȌ ‹• ƒ†‡ ƒ˜ƒ‹Žƒ„Ž‡ –‘ –Š‡ ‡…”‡–ƒ”‹ƒ– Žƒ–‡•– „› ‡„”—ƒ”›
15th, 2017 (5:00 PM). You can check & update your address online at www.dosonline.org.

Resolutions / Suggestions for General Body Meeting

DOS members are requested to send us their Suggestions / Resolutions to be discussed in the General Body Meeting to be
Š‡Ž† ‘ ’”‹Ž ͻ–Šǡ ʹͲͳ͹Ǥ Š‡•‡ ™‹ŽŽ „‡ †‹•…—••‡† ϐ‹”•– ‹ –Š‡ š‡…—–‹˜‡ ‡‡–‹‰ ƒ† –Š‡ ˆ‘”™ƒ”†‡† –‘ –Š‡
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Last date of receipt of suggestions/resolutions is 25th February, 2017 (5:00 PM).

www. dos-times.org 55

MONTHLY MEETING KORNER

MANAGEMENT OF PERIPHERAL CORNEAL DISEASES

Dr. Uma Sridhar MS, DNB, FRCS(Ed) ‘ˆ ‹ϐ‹Ž–”ƒ–‡Ǥ ›’‹…ƒŽŽ› –Š‡•‡ —Ž…‡”• ‡‡† „‘–Š –‘’‹…ƒŽ ƒ–‹„‹‘–‹…•
Cornea Services, and steroids to heal.
ICARE Eye Hospital, Noida, U.P.
PERIPHERAL ULCERATIVE KERATITIS
Peripheral cornea differs from the central cornea in Associated with collagen vascular disorders as apposed
many respects. It differs from the central cornea
not only anatomically but due to its proximity to Mooren’s ulcer which has no apparent associated systemic
to conjunctiva, sclera and episclera, it is prone disease. PUK is a crescentic destructive peripheral corneal
to be involved in the degenerative, infective, lesion with an overlying epithelial defect and underlying
immune and neoplastic diseases that affect these •–”‘ƒŽ ‹ϐŽƒƒ–‹‘ ƒ† –Š‹‹‰Ǥ  ˆƒ…–ǡ ȋ ƒ„Ž‡ ͳȌ ‰‹˜‡• ƒ
structures. differential diagnosis of peripheral corneal ulcerative lesions.
Anatomically, the peripheral cornea derives its nutrition
partly from the anterior conjunctival blood vessels and the There are many collagen vascular disorders that cause
deep episcleral vessels. Importantly, lymphatics accompany PUK such as rheumatoid arthritis, Wegener’s granulomatosis,
these vessels and drain into the regional lymph nodes. The polyarteritis nodosa, relapsing polychondritis and systemic
immunoglobulins thus get access to peripheral cornea. The lupus erythmatosus. Treatment of the underlying disease
content of immunoglobulins like IgG and IgA is similar in is important for saving sight as well as reducing systemic
central and peripheral cornea. But IgM is present more in the morbidity and mortality.
peripheral cornea due to its larger size which may prevent its
diffusion into the central cornea. Work up of a case of peripheral ulcerative keratitis includes
Š‡ ‹—‘‰Ž—„—Ž‹• ‰
ƒ† ‰ ϐ‹š …‘’Ž‡‡– ˜‹ƒ –Š‡ extensive history taking and thorough systemic examination.
classical pathway. Complement C1 is present in larger quantity Local infectious causes must be ruled out by corneal scraping
in the peripheral cornea. Langerhans cells are present in and cultures. Investigations will include complete blood
the conjunctiva and peripheral cornea. They are the antigen ’‹…–—”‡ǡ ‹†‹…‡• ‘ˆ •›•–‡‹… ‹ϐŽƒƒ–‹‘ •—…Š ƒ• ‡”›–Š”‘…›–‡
’”‡•‡–‹‰ …‡ŽŽ• ƒ• ™‡ŽŽ ƒ• •‡…”‡–‡ ‹ϐŽƒƒ–‘”› ‡†‹ƒ–‘”•Ǥ sedimentation rate and C reactive protein ,urinanalyis, chest
Neutrophils, lymphocytes, mast cells and plasma cells are also and sinus X- rays, rheumatoid factor and antineutrophilic
present in the peripheral cornea1-3. cytoplasmic antibodies (ANCAs).
Histopathologically, the peripheral corneal limbus is
the transition zone between the conjunctiva and the cornea. Additional investigations may be required and repeated
0.15 % of the epithelial cells in the peripheral cornea are the evaluation by a rheumatologist is mandatory to systemically
stem cells. The stem cell niche is also present at the limbus in manage the disease process. Often it is necessary to sensitise
the palisades of Vogt. The stem cells have unique properties. the rheumatologist and immunologist that active ocular
Dz –‡‡••dz ‹†‹…ƒ–‡• –Š‡ ‹ϐ‹‹–‡ …ƒ’ƒ…‹–› ˆ‘” ”‡‡™ƒŽ ƒ• ™‡ŽŽ ƒ• involvement is possible in spite of apparent “burnt out”
the capability to differentiate into daughter cells. systemic disease process.
Disorders involving peripheral cornea may be purely
ocular or they may be associated with systemic diseases CASE BASED DISCUSSION
It has been observed that the Herpes virus keratitis PUK associated with rheumatoid arthritis
in central or paracentral cornea behaves differently from Case 1
peripheral corneal HSV keratitis. More often than not, the
peripheral dendritic ulcers (Figure 1) may be more recurrent A sixty year old female patient presented with decreased
and have immunological sequelae which need treatment with ˜‹•‹‘ ‹ Š‡ Ž‡ˆ– ‡›‡ •‹…‡ ϐ‹ˆ–‡‡ †ƒ›•Ǥ Š‡”‡ ™ƒ• ’ƒ‹ǡ ”‡†‡••ǡ
use of long term topical steroids.
Contact lens induced peripheral ulcers (Figure 2 A and Figure 1: Peripheral dendrites due to Herpes Simplex virus keratitis
B) differ from microbial keratitis in several ways. They are <
2 mm in size, do not have an overlying epithelial defect, the www. dos-times.org 57
surrounding cornea is clear and they resolve spontaneously
after discontinuation of contact lenses.
Marginal keratitis (Figure 3) typically occurs at 2, 4, 8 and
10 o’clock positions where the lids touch the cornea. They are
†—‡ –‘ •–ƒ’Š›Ž‘…‘……ƒŽ –‘š‹• ™Š‹…Š ˆ‘” ƒ ‹ϐ‹Ž–”ƒ–‡ ™Š‹…Š
have a lucid interval from the limbus. There may be no overlying
epithelial defect and few blood vessels may be present at the site

MONTHLY MEETING KORNER

Ocular Non infectious Table 15 Non Infectious

Infectious Mooren’s ulcer, Terrien’s Marginal Systemic Infectious Rheumatoid arthritis, Giant cell
Degeneration, Pellucid Marginal arteritis, Wegener’s granulomatosis Systemic
Infectious degeneration, Keratonconjuctivitis Infectious lupus erythematosus, Polyarteritis nodosa,
Bacterial Sicca, Staphycoccal Blepharitis Sjorgren’s syndrome, Schonlein-Henoch purpura
Viral Rosacea, Neurotrophic / Tuberculosis, Malignancies, Mixed cryoglobulinemia, Crohn’s
Acanthamoeba Neuroparalytic causes, Nutritional Syphilis, HIV, bacillary regional ileitis, Ulcerative colitis, Rosacea, Churg-
Fungal †‡ϐ‹…‹‡…‹‡•ǡ Š‡‹…ƒŽ ‹Œ—”› dysentery, STD like Strauss syndrome, Relapsing polychondritis,
to the eye, Contact Lens usage, Gonorrhoea,VZV Progressive systemic sclerosis Serum sickness,
surgical, traumatic Psoriasis, Stevens Johnson Syndrome, Cicatricial
pemphgoid, Sarcoidosis, Behcet’s disease

Figure 2: A and B Contact lens induced peripheral ulcers

watering and irritation. She had history advised to strictly adhere to her systemic her right eye showed mild conjunctival
of rheumatoid arthritis, with RA factor medications. staining and low tears miniscus. Left
being positive and was on systemic eye showed conjunctival congestion,
methotrexate and hydroxycholoquine Patients with Rheumatoid arthritis supero nasally cornea showed peripheral
for the same. In the left eye, there was a must also be advised regarding the crescent shaped lesion, nearly 3 clock
peripheral crescent shaped thinning in systemic implications of the disease hours in extent overlying epithelial
the cornea almost 3 clock hours in extent. process. Involvement of pulmonary defect, underlying stromal thinning and
There was overlying epithelial defect and system, osteoarticular involvement, ‹ϐ‹Ž–”ƒ–‹‘ ȋ ‹‰—”‡ ͷȌǤ ‹…”‘„‹‘Ž‘‰‹…ƒŽ
—†‡”Ž›‹‰ •–”‘ƒŽ ‹ϐ‹Ž–”ƒ–‡ ȋ ‹‰—”‡ ͶȌǤ  and the sheer debilitating nature of the work up was negative and based on
the right eye, the cornea showed a small disease must be explained to the patient history and clinical examination,
area of stromal thinning in the periphery. and importance of disease modifying diagnosis of PUK was made. Topical
Schirmer 1 test showed a wetting of 6 mm agents (DMARDs), their possible side steroids and lubrication was started. The
in both eyes. The microbiological workup effects and need for physiotherapy must patient was referred to a rheumatologist
of the lesion in the left eye was negative. be emphasised. Rheumatologists should who started her initially on oral steroids
Based on history and clinical examination, be sensitised to the fact that active ocular and later on hydroxycholoquine and oral
a diagnosis of PUK was made. Topical involvement means active disease process methotrexate. Conjunctival resection at
lubricant drops and topical steroid drops even if rest of the systems indicate “burnt the site of lesion along with cyanoacrylate
were started. The patient was referred out” disease. adhesive and bandage contact lens
back to her rheumatologist to titrate application was done nearly one month
dosage of her systemic medication. She Case 2 after systemic treatment was iniciated.
improved on treatment. After one year, –Š‹”–› ϐ‹˜‡ ›‡ƒ” ‘Ž† ˆ‡ƒŽ‡ ’ƒ–‹‡– Š‡ •Š‘™‡† •‹‰‹ϐ‹…ƒ– ‹’”‘˜‡‡– ‹
she came back with a similar lesion, this her symptoms and signs and had a BCVA
time in her right eye. She reported having presented with pain, redness, watering, of 6/6 after six months (Figure 6).
discontinued her systemic medications and photophobia and decreased vision
she was restarted on topical drops and ‹ Š‡” Ž‡ˆ– ‡›‡ •‹…‡ ϐ‹ˆ–‡‡ †ƒ›•Ǥ Š‡ ™ƒ• Rheumatoid arthritis was found to
known case of rheumatoid arthritis on be the most common cause (34%) of
treatment off and on. On examination,

58 DOS TIMES - JANUARY- FEBRUARY 2017

MONTHLY MEETING KORNER

Figure 3: Marginal keratitis Figure 4: 2GTKRJGTCN EQTPGCN VJKPPKPI CPF KPſNVTCVKQP
27- KP
TJGWOCVQKF CTVJTKVKU
ECUG

Figure 5: 2GTKRJGTCN EQTPGCN VJKPPKPI CPF KPſNVTCVKQP KP TJGWOCVQKF Figure 6: *GCNGF 27- KP ECUG
CTVJTKVKU
ECUG

PUK amongst all the collagen vascular may also occur. Immunosuppressives like age groups was unilateral and benign
disorders6 and 44 % of cases of PUK in cyclophosphamide can prolong the life (benign Mooren’s).
RA were bilateral. PUK and necrotizing span and when ANCA becomes negative,
scleritis were indicators that the disease it is a good prognostic indicator7. Later authors have variable data
had progressed from being a synovial for uni and bilaterality of the disease in
microvasculitis to a systemic vasculitis PUK can also occur in relapsing various age groups9-11.
and hence was associated with higher polychondritis which affects the
incidence of morbidity and mortality. cartilages of ear, nose, larynx and trachea. Mooren’s ulcer presents with severe
Higher incidence of post-operative PUK in Scleritis is more common than PUK. pain which may be out of proportion
RA patients has been reported probably –‘ –Š‡ ‹ϐŽƒƒ–‹‘Ǥ ‡…”‡ƒ•‡† ˜‹•—ƒŽ
because surgical trauma can trigger PUK can also occur in poly acuity may be due to the irregular
immune complex mediated vasculitis in arteritis nodosa and in systemic lupus astigmatism, central corneal involvement
these patients. erythmatosus though PUK is more or due to associated iritis. Initially, patchy
common in the former. •–”‘ƒŽ ‹ϐ‹Ž–”ƒ–‡• ƒ› „‡ ’”‡•‡– ‹
PUK IN OTHER CVDS the periphery of the cornea which may
MOOREN’S ULCER coalesce to form a shallow furrow with an
Wegener’s granulomatosis affects overlying epithelial deffect. The shallow
the eyes, kidney and respiratory tract. Unlike PUK in collagen furrow spreads circumferentially and
‹ƒ‰‘•‹• ‹• …‘ϐ‹”‡† „› Š‹•–‘’ƒ–Š‘Ž‘‰›Ǥ vascular disorders, Mooren’s ulcer then centrally. The stromal involvement
Antineutrophil cytoplasmic antibody test is unaccompanied by systemic is deeper than appreciated clinically
ȋ Ȍ ‹• Š‹‰ŠŽ› •‡•‹–‹˜‡ ƒ† •’‡…‹ϐ‹…Ǥ manifestations and there is no associated extending to nearly half the depth of
ANCA with a diffuse granular cytoplasmic scleritis. the stroma. The central leading edge
staining pattern, cANCA is more sensitive is overhanging and steep. Adjacent
ƒ† •’‡…‹ϐ‹… ˆ‘” –Š‡ †‹•‡ƒ•‡Ǥ ‹• –Š‡ Men are affected more than women. conjunctiva, episclera and sclera may be
‘•– …‘‘ ƒ–‡”‹‘” •‡‰‡– ϐ‹†‹‰Ǥ According to Wood and Kaufman8 who ‹ϐŽƒ‡†Ǥ ”‹–‹• ƒ› „‡ ƒ••‘…‹ƒ–‡† ƒ†
Conjunctivitis, episcleritis and scleritis studied nine cases of Mooren’s ulcer and glaucoma and cataract may be associated.
came to the conclusion that Mooren’s Perforation can occur in up to 40 % of
ulcer in younger age was bilateral and
severe (malignant Mooren’s)and in older cases.

www. dos-times.org 59

MONTHLY MEETING KORNER

Figure 7: /QQTGPŏU WNEGT
ECUG Figure 8: /QQTGPŏU WNEGT
ECUG CHVGT CPPWNCT NCOGNNCT ITCHV

Various etiologies have been Anterior chamber was formed. Lens was improving to 6/60 with pin hole. On
mildly cataractous. Fundus was within examination, his right eye was quiet;
proposed such as an associated Hepatitis normal limits. His collagen vascular cornea has a small area of peripheral
disease work up was negative. A diagnosis thinning which was unremarkable. His
C infection, parasitic infestation, physical of Mooren’s ulcer was made. Three left eye was congested. Cornea showed
pulse doses of iv methyl prednisolone vascularisation in superior cornea with
trauma, surgical trauma, Herpes Simplex ™‡”‡ ‰‹˜‡ –‘ ”‡†—…‡ –Š‡ ‹ϐŽƒƒ–‹‘ lipoid deposits and peripheral thinning
in the eye. This was followed up by oral and ectasia without an overlying
and Zoster infection etc12. methotrexate weekly starting from 5 mg epithelial defect. Anterior chamber
per week. Peripheral annular lamellar was well formed. Rest of the ocular
Pathophysiological mechanism graft was done for the peripheral corneal examination was unremarkable. Systemic
thinning and guttering (Figure 8) which collagen work up was unremarkable. He
of Mooren’s ulcer suggests that it is was followed up a year later by central had no other systemic disease. A clinical
corneal graft with cataract surgery. †‹ƒ‰‘•‹• ‘ˆ ‹ϐŽƒƒ–‘”› ‡””‹‡ǯ•
an autoimmune process with humoral marginal degeneration was entertained
TERRIEN’S MARGINAL and topical steroids were given for the
and cellular components. Decrease in ‹ϐŽƒƒ–‹‘Ǥ Š‡ ’ƒ–‹‡– ’”‡•‡–‡† ‘™
DEGENERATION and then in the next three to four years
number of suppressor T cells as apposed ™‹–Š ‘……ƒ•‹‘ƒŽ ‡’‹•‘†‡• ‘ˆ ‹ϐŽƒƒ–‹‘
Terrien’s marginal degeneration which was managed by topical steroids
to Helper T cells may lead to unregulated is a rare peripheral bilateral corneal ȋ ‹‰—”‡ ͻȌǤ  „‡–™‡‡ –Š‡ ‹ϐŽƒƒ–‘”›
degenerative disease which is more episodes, rigid gas permeable contact
production of autoantibodies, resulting commonly seen in males in age group lens was tried which improved his BCVA
ʹͲǦͶͲ ›‡ƒ”•Ǥ – ™ƒ• ϐ‹”•– †‡•…”‹„‡† „› to 6/12 , but he was not interested in
in deposition of immune complexes, Terrien in 1900s13. The disease process using the lens.
starts in the superonasal quadrant of the
activation of complements and …‘”‡ƒ ƒ• ϐ‹‡ǡ ›‡ŽŽ‘™Ǧ™Š‹–‡ ’—…–ƒ–‡ The patient presented with intense
stromal opacities that may progress pain and watering in his left eye. On
‹ϐŽƒƒ–‘”› …‡ŽŽ ‹ϐ‹Ž–”ƒ–‹‘Ǥ along the circumference of the cornea. examination, anterior chamber was
There is vascularization at the base of the ϐŽƒ– ƒ† ‡‹†‡Žǯ• –‡•– ™ƒ• ’‘•‹–‹˜‡ ƒ– ͷ
Diagnosis of Mooren’s ulcer is Ž‡•‹‘•ǡ ƒ† •…ƒ””‹‰ ƒ† Ž‹’‹† ‹ϐ‹Ž–”ƒ–‹‘ 0’clock position. Tissue adhesive and
at its leading edge Austin and Brown14 bandage contact lens application helped
essentially by exclusion. Work up for Šƒ˜‡ †‡•…”‹„‡† ƒ ‹ϐŽƒƒ–‘”› ˜ƒ”‹ƒ– to form the anterior chamber. Topical and
of Terrien’s marginal degeneration in oral steroids were given to reduce the
collagen vascular disorders and for younger subjects with no history of ‹ϐŽƒƒ–‹‘Ǥ  ƒ—Žƒ” Žƒ‡ŽŽƒ” ‰”ƒˆ–
rheumatoid disease; this is characterized was done due to the extreme peripheral
systemic infections such as syphilis and by recurrent and disabling attacks of thinning (Figure 10). Topical and oral
ƒ…—–‡ ’ƒ‹ ƒ† ‹ϐŽƒƒ–‹‘Ǥ steroids were continued in tapering
tuberculosis is mandatory and when all Case 4 †‘•‡• –‘ ”‡†—…‡ –Š‡ ‹ϐŽƒƒ–‹‘Ǥ  Žƒ•–
follow up the patient had all sutures out
disorders are excluded, a diagnosis of A thirty year old male patient and his BCVA improved to 6/9 with Rose
presented with decrease in vision in k lens which he was happy to wear due to
Mooren’s ulcer can be entertained. his left eye since 2 years . this was improved vision and comfort. Pentacam
progressive. He had redness, pain, analysis showed improved peripheral
Management of this rare but photophobia and watering since a few thickness (Figure 11).
days. UCVA in right eye was 6/6 and
†‡˜ƒ•–ƒ–‹‰ †‹•‡ƒ•‡ ‹• †‹ˆϐ‹…—Ž–Ǥ –‡’ Ž‡ˆ– ‡›‡ ™ƒ• ϐ‹‰‡” …‘—–‹‰ ͵ ‡–‡”•

wise management has been proposed.

Topical steroids followed by conjunctival

resection, systemic immunosuppressants,

surgical procedures and further

rehabilitation.

Case 3
A seventy year old male patient

presented to the cornea clinic with
decreased vision, pain and photophobia
in his left eye since a month. His right eye
had similar complaints a few years earlier
and he has completely lost vision in that
eye. He had no history of any systemic
disease. On examination, his right eye
was phthisical. His left eye showed
conjunctival congestion, cornea showed
a peripheral gutter almost 8 clock hours
(Figure 7) with steep overhanging central
edge and extending almost to the limbus.

60 DOS TIMES - JANUARY- FEBRUARY 2017

MONTHLY MEETING KORNER

Figure 9: 6GTTKGPŏU OCTIKPCN FGIGPGTCVKQP
ECUG Figure 10: Annular lamellar graft in case 4

Peripheral Ulcerative Keratitis. Surv

ophthalmol. 1999;43:379

5. Chow C.Y.C, Foster C.S . Mooren’s ulcer

.Int Ophthalmol Clin,1996, 36 :1

6. Foster CS, Forstot SL, Wilson

LA.Mortality rate in rheumatoid

arthritis patients developing

necrotising scleritis or peripheral

ulcerative keratitis. Effects of systemic

immunosuppression.Ophthalmology

1984;91: 1253-63

7. Robin JB, Schanzlin DJ , Veroty SM et

al. Peripheral corneal disorders. Surv

Ophthalmol 1986;31:1-36.

8. Wood T, Kaufman H. Mooren’s ulcer .Int

Ophthalmol Clin 1986;26:91.

9. Tabbara KF. Mooren’s ulcer. Int

Ophthalmol Clin 1986; 26:91.

10. FrangiehT, Kenyon KR. Mooren’s ulcer.

In:Brightbill FS,ed.Corneal surgery:

Figure 11: 2GPVCECO CPCN[UKU CHVGT CPPWNCT NCOGNNCT ITCHV
ECUG Theory, technique, tissue, ed 2 .St Louis

:Mosby,1993.

11. Keitzman B. Mooren’s ulcer in Nigeria.

CONCLUSION REFERENCES Am J Ophthalmol 1968 ;65:679.

Peripheral corneal diseases are 1. Robin JB, Schanzlin DJ et al. Peripheral 12. Foster CS, et al. The immunopathology
varied in their presentation. They are Corneal Disorders. Surv ophthalmol.
challenging to diagnose and manage. The 1986; 31:1 of Mooren’s ulcer . Am J Ophthalmol
…Ž‹‹…ƒŽ ’”‡•‡–ƒ–‹‘ ƒ› „‡ •—ˆϐ‹…‹‡–
for the diagnosis. However, infectious 2. Hogan M.J, Alvarado J.A: The Limbus. In 1979;88:2.
etiology always needs to be ruled out Histology of the Human eye. An Atlas
by microbiologic work up. Systemic and textbook. W B Saunders, 2nd ed, 13. Terrien F. Dystrophie marginale
investigations have to be tailored to 1971;112-182.
the individual disease. Management symétrique des deux cornées avec
strategies have to be planned according ͵Ǥ ‘†‹‘
ǣ ϐŽƒƒ–‘”› †‹•‡ƒ•‡• ‘ˆ
to the presentation and long term the peripheral cornea. Ophthalmology. astimgatisme régulier conséquetif et
morbidity and mortality may be reduced 1988; 95:463
by appropriate treatment. guérison par la cautérisation ignée.
4. Messmer EM, Foster CS: Vasculitic
Arch Ophthalmol. 1900;20:12.

ͳͶǤ —•–‹ ǡ ”‘™ Ǥ ϐŽƒƒ–‘”›

Terrien’s marginal degeneration. Am J

Ophthalmol. 1981;92:189–192.

Financial Interest: Š‡ ƒ—–Š‘” †‘‡• ‘– Šƒ˜‡ ƒ› ϔ‹ƒ…‹ƒŽ ‹–‡”‡•– ‹ ƒ› ’”‘…‡†—”‡Ȁ’”‘†—…– ‡–‹‘‡† ‹ –Š‹• ƒ—•…”‹’–Ǥ
Guest Case presented in the DOS Monthly Clinical Meeting at Goyal Eye Institute, November 27, 2016.

www. dos-times.org 61

MONTHLY MEETING KORNER

CATARACT IN THE SILICONE OIL FILLED EYE

Dr. Hemlata Gupta MS, DNB, FIACO At 11 months postoperative visit his Right eye had 6/60
Consultant, Cataract and Refractive Surgery, vision with a refraction of + 5.5 D. Cornea was clear, anterior
Centre For Sight, Safdarjung Enclave, New Delhi …Šƒ„‡” †‡‡’ ƒ† “—‹‡– ™‹–Š ˆ‡™ ‡—Ž•‹ϐ‹‡† •‹Ž‹…‘ ‘‹Ž †”‘’Ž‡–•
in anterior chamber. There was posterior subcapsular cataract
An 18 year old nondiabetic male presented to ȋ ‹‰—”‡ ʹƒȌ ƒ† ˜‹–”‡‘—• …ƒ˜‹–› ™ƒ• ϐ‹ŽŽ‡† ™‹–Š •‹Ž‹…‘ ‘‹ŽǤ —’
us with marked loss of vision right eye since Disc Ratio was 0.3 with healthy NRR. Retina was well attached
6 months. He gave history of blunt trauma with 360 degree laser marks in periphery (Figure 2b).
with ball 6 month back. He was diagnosed as
post-traumatic Total retinal detachment with IOP was 18mm of Hg. Specular microscopy was done
PVR and break was localised in upper nasal to know the endothelial cell count and morphology which
quadrant (Figure 1). Patient underwent pars plana vitrectomy was essentially within normal limits (Figure 2c). Patient was
with scleral buckling with endolaser with silicon oil injection. advised to undergo MICS with PCIOL with silicon oil removal
His postoperative best corrected visual acuity was 6/60 and through post capsulorhexis. IOL power was calculated by IOL
retina was well attached at all postoperative visits. master (Zeiss) in silicon oil mode. IOL power was + 23.5 D.

Figure 1 Surgery was done under local anaesthesia using peribulbar
block. Cataract surgery was done through 2.8 mm clear
…‘”‡ƒŽ ‹…‹•‹‘Ǥ – –Š‡ ‡† ‘ˆ •–ƒ†ƒ”† ’Šƒ…‘‡—Ž•‹ϐ‹…ƒ–‹‘
after cortical cleanup a 3mm posterior capsulorhexis is
made. Silicon oil was removed using bimanual irrigation and
aspiration cannula wherein we use the irrigation cannula for
infusion and aspiration cannula just to depress the posterior
Ž‹’ ‘ˆ …‘”‡ƒŽ –—‡Ž ˆ‘” ‡ƒ•› ‡ˆϐŽ—š ‘ˆ •‹Ž‹…‘ ‘‹ŽǤ ‹Ž ”‡‘˜ƒŽ ‹•
completed when you see last bubble of oil coming out. Then AC
was formed with viscoelastic and hydrophobic foldable acrylic
lens was implanted in the capsular bag. Corneal tunnel was
then sutured with 10-0 nylon suture. Fundus was examined by
indirect ophthalmoscopy at the end of the surgery to ensure
that the retina remained attached and no large silicon oil
bubbles remained in the vitreous cavity.

On POSTOP day 1, BCVA was 6/18. Slit lamp biomicroscopy
showed clear cornea and stable IOL (Figure 3a). Retina was well
attached and laser marks seen were seen in periphery (Figure
3b). Specular microscopy was repeated at one month and 3
months which showed stable counts.

Figure 2a & 2b

www. dos-times.org 63

MONTHLY MEETING KORNER Visual Outcome

Endothelial cell count was 3557/ mm2
with no guttate changes

$%8# KORTQXGF KP G[GU


in literature using either passive diameter, which gives a greater viewing
hydrodynamic expression or active area for fundus visualization.
suction of silicon oil through anterior
”‘—–‡Ǥ Šƒ…‘‡—Ž•‹ϐ‹…ƒ–‹‘ …ƒ „‡ †‘‡ We did a study at centre for sight
through scleral tunnel or clear corneal to analyse the visual outcome and
incision and silicon oil can be removed complications associated with this
using infusion cannula/ AC maintainer / technique.
phaco irrigation and aspiration cannula.
A total of 50 eyes were analysed
Prerequistes for anterior route retrospectively. Age range was 29 to 71
SOR are silicon oil should have been years ( mean age – 43 years). Interval
‡—Ž•‹ϐ‹‡†ǡ •–ƒ„Ž‡ ƒ––ƒ…Š‡† ”‡–‹ƒǡ ‘ between VR surgery and SOR was 6
active proliferation or traction, no weeks to 12 months, median interval

Figure 2c: Specular microscopy

1 day Postop. VA – 6/18 (-1.25 Dcl x 500) Retina On IOP-13 mm of Hg

Figure 3a & 3b

DISCUSSION epiretinal membrane requiring removal. being 11 weeks. IOP were stable in all
There should not be any open break / patients. Mean duration of surgery was
There are many patients who •—„”‡–‹ƒŽ ϐŽ—‹† ‡‡†‹‰ ‹–‡”˜‡–‹‘Ǥ 17.2±7 mins.
develop cataract by the time we need
to remove silicon oil post VR surgery. Preferred IOL with silicon oil in situ is BCVA improved in 39 eyes (78 %)
Combined phacoemulsication and silicon Š›†”‘’Š‹Ž‹… ƒ…”›Ž‹… ǡ •—”ˆƒ…‡ ‘†‹ϐ‹‡† . In rest 11 eyes reason of poor visual
oil removal through anterior approach with heparin coating to reduce postop acuity was macular pucker in 4 eyes,
is an established technique nowadays. ‹ϐŽƒƒ–‹‘ǡ ƒ† ™‹–Š ƒ ͵͸ͲǦ†‡‰”‡‡ foveal thinning in 4 eyes, disc pallor in 3
There are various techniques mentioned square edge design and large optic eyes. There was no case of intraoperative

64 DOS TIMES - JANUARY- FEBRUARY 2017