Editor-in-chief Volume 22 No. 3
November-December
M. Vanathi 2016
Section Editors Editorial Capsule Monthly Meeting Korner
Cataract & Refractive Retina & Uvea 7 Chances we get and the Choices 51 Nasal Endoscopy and Lacrimal
we make system: What Lies Beyond
Umang Mathur Pradeep Venketesh Routine DCR! Report of a Rare
Saurabh Sawhney Parijat Chandra 9 Special Message Sac in Ethmoid Sinus Syndrome
Sanjiv Mohan Manisha Aggarwal Featuring Sections Snapshot
S. Khokhar Shahana Majumdhar 53 Ocular Toxoplasmosis
Researh Methodology 55 Concurrent Bilateral Necrotizing
Cornea & Oular Surface Rohan Chawla 11 Systematizing Ophthalmology Viral Stromal Keratitis
Uma Sridhar Ravi Bypareddy and Coping with the Challenges
Deepa Gupta Ophthalmoplasty & Diagnostics Discussion
Cornea 59 Role of Histopathology in
Umang Mathur Ocular Oncology 15 Dry eye Disease After Refractive Diagnosis of Ocular Surface
Ramendra Bakshi Neelam Pushker Surgery-Current Scenario Squamous Neoplasia
Manisha Acharya Maya Hada 19 Neurotrophic Keratopathy Masquerades
Noopur Gupta Sangeeta Abrol Refractive Surgery Innovations
Glaucoma Rachna Meel 23 Unfolding the Concept of 61 Adapters in Smart phone: How
Intracorneal Ring Segment to make your own?
Dewang Angmo Squint & Implantation (ICRS)
Reena Sharma Neuro-ophthalmology ͷ ǯ ϐǣ
Sunita Dubey Digvijay Singh Cataract Device and Intravitreal Injection
Viney Gupta Zia Chaudhuri 29 IOL Power Calculations Guide
Kanak Tyagi Suma Ganesh (Part-3)– Special Situations
Delhi Advisory Board DOS TIMES Quiz
Y.R. Sharma Mahipal Sachdev 67 QUIZ - Episode 3
Atul Kumar Radhika Tandon
P.V. Chadha Jolly Rohtagi Glaucoma DOS Crossword
37 Recent Advances in Perimetry 69 DOS CROSSWORD-
Noshir M. Shroff J.C. Das
Rajendra Khanna B.P. Gulliani Ocular Oncology Episode 3
Vimla Menon Ritu Arora 43 An Update on Ocular Oncology
H.K. Yaduvanshi Kamlesh News Watch
70 DOS Election Notice
Anita Panda G.K. Das Ocular Microbiology 73 DOS Winter Award
Pradeep Sharma Lalit Verma 47 Primary Microscopy as a Point of 74 For DOS Voting Members
Ramanjit Sihota Tanuj Dada Care Test in Ophthalmology 77 Obituary
Harish Gandhi Abhishek Dagar 79 DOS Winter Photographs
Anup Goswami Sarita Beri
89 iDOS programme
Rajpal P.K. Sahu
Mandeep Bajaj Kamlesh Merry Christmas
&
B. Ghosh Taru Dewan
Rajiv Garg H.S. Sethi A Very Happy New Year
R.B. Jain H.K. Tewari www. dos-times.org 3
National Advisory Board
R.D. Ravindran Barun Nayak
Debashish Bhattacharya Venketesh Prajna
R. Revathi S. Natarajan
Yogesh Shah Amod Gupta
Arup Charaborti Jagat Ram
Anita Raghavan Amar Agarwal
Chandna Chakraborti Mangat Ram Dogra
Sushmita Shah D. Ramamurthy
Sushmita Kaushik T.P. Lahane
Pravin Vadavalli Samar Basak
Somshiela Murthy Cyrus Mehta
Sri Ganesh Mahesh Shanmugam
M.S. Ravindra J. Biswas
Rohit Shetty Srinivas Rao
Mallika Goyal Nikhil Gokale
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
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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
DOS EXECUTIVE MEMBERS
Executive Committee:
ϐ
Dr. Rishi Mohan Prof. Kamlesh Dr. M. Vanathi
President Vice President General Secretary
Dr. Arun Baweja Dr. Vipul Nayar Dr. Ruchi Goel Dr. Deven Tuli
Joint Secretary Treasurer Editor ϐ
DOS Representative to AIOS
Executive Members
Dr. Jatinder Singh Bhalla Dr. Bhuvan Chanana Dr. Anshul Goyal Dr. Avnindra Gupta Dr. Ajay Aurora
Dr. Rajat Jain Dr. Deepankur Mahajan Dr. J. K.S. Parihar Dr. Manavdeep Singh Dr. Namrata Sharma
Ǧ ϐ
Dr. Cyrus M. Shroff Dr. Rajesh Sinha Dr. Sanjeev Gupta
Ex-President Ex-Secretary Ex-Treasurer
DOS HALL OF FAME Tejpal Saini Satinder Sabharwal DOS General Secretaries
DOS PRESIDENTS Satish Sabharwal A.K. Grover
J.C. Das Hari Mohan Arun Sangal
S.N. Mitter A.C. Chadha N.C. Singhal Gurbax Singh R.S. Garkal R.V. Azad
H.S. Trehan M.S. Boparai Madan Mohan Noshir M. Shroff S.R.K. Malik B. Ghosh
Tej Pal Saini N.N. Sood Pratap Narain Mahipal S. Sachdev Madan Mohan Mahipal Sachdev
L.P. Agarwal P.K. Jain (Brig.) R.C. Sharma Lalit Verma J.C. Bhutani Atul Kumar
D.C. Bhutani L.D. Sota S. Bharti S.C. Sabharwal Lalit Verma
R.C. Aggarwal L.D. Sota B.N. Khanna Sharad Lakhotia A.C. Chadha Dinesh Talwar
S.K. Angra R.N. Sabharwal P.V. Chadha Pratap Narain Harsh Kumar
S.N. Kaul D.K. Mehta B.P. Guliani S.K. Angra J S. Titiyal
S.N. Kaul Y. Dayal N.L. Bajaj Harbansh Lal G. Mukherjee Harbansh Lal
H.S. Trehan K.P.S. Malik Mathew M. Krishna J S. Titiyal H.K. Tewari Namrata Sharma
Hari Mohan R.B. Jain Rajendra Khanna Amit Khosla
R.S. Garkal G. Mukherjee Prem Prakash Cyrus Shroff R. Kalsi Rohit Saxena
J.C. Bhutani R.V. Azad D.K. Sen Rishi Mohan D.K. Mehta Rajesh Sinha
S.R.K. Malik P.C. Bhatia M. Vanathi
P.K. Khosla K.P.S. Malik
K. Lall
A.K. Gupta
B. Pattnaik
Sincere thanks to all DOS OFFICE STAFF : ϐ
ǣ Parveen Kumar DOS Accountant: Sandeep Kumar DOS TIMES Assistant: Sunil Kumar
DJO Assistant: Varun Kumar Library Attendant: Niyaj Ahmad ϐ
ǣ Harshpal
5 DOS TIMES - NOVEMBER-DECEMBER 2016
EDITORIAL CAPSULE
HANCES WE GET AND THE HOICES WE MAKE
“I don’t regret the things I’ve done, I regret the things I didn’t do when I had the chance.”
– Unknown
Dear DOS Members,
We have passed the midterm mark of yet another year at DOS. Much seen
and experienced as we plan to complete the rest of this executive’s term with
hopes to add more feathers to our cap.
ʹͲͳͷ Ȃ ʹͲͳ ϐ
to all DOS members for the tremendous support and appreciation to all
academic activities undertaken. We are overwhelmed with the show of
strength and solidarity by our members to Delhi Ophthalmological Society.
In tested times of demonetization troubles which torpedoed right on
the eve of our much awaited midterm DOS meeting 2016 - winterDOS 2016:
Ophthalmic VISTA, I am happy to announce that our meeting saw the one
of the highest attendance till date for a midterm meeting with fabulous
attendance and appreciation to all details of our program ensemble. The
changed ambience of winterDOS 2016 meeting was acknowledged with Dr. M.Vanathi
warmth and appreciation. The fellowship program at the Kingdom of Dreams
saw interaction of many who had never ventured to attend dinner program
and was a runaway success with a refreshing assembly of entertainment, music, dinner and family interaction.
All our winterDOS 2016 meeting programs – Biometric Barometer, DOL 2016 season II, Diabetic Eye – Know All,
Retinal Reverberations, Corneal Collaborations, Oculoplasty & oncology Odissi, Squint & Neuro-ophthal Master
class, Glaucoma Concepts and guest lectures were all highly appreciated by all delegates and faculty. Our programs
ϐ
Ǥ
I wish to acknowledge the support of Dr R P Centre, AIIMS and Centre of Sight for extending wonderful live
surgery sessions. The assembly of variety of ophthalmic subspeciality surgeries from Dr R P Centre and the cataract
surgeries from CFS were high points for our meeting. I wish to thank all faculty who made it a wonderful success.
ϐ
the conference to reach all residents and we saw a overwhelming response to all the teaching program ensemble.
Once again, the DOS executive wishes to express its gratitude and appreciation to Dr R P Centre for supporting the
teaching program by opening up its portals to all residents from across the country.
ǡ
ǯ ȋʹͲͳͷ Ȃ ʹͲͳȌ ϐ
performance is one of the best ever in the history of DOS. We could have capitalized further with the WSPOS meeting
knocking on our portals. Perhaps its loss, will enable our society to look at setting into place a more conducive
framework for conducting international meetings in delhi in the future. I look forward to steering DOS towards that
goal in this term and to work in unison with our future executives as well to achieve this cause.
As we twist and turn through times treading tall with equivocal acknowledgement to critical acclaim and
overwhelming appreciation for all that we are doing for DOS, we have but one thought in mind – to perform with
excellence and give for DOS a platform of high academic excellence beyond that which existed in earlier times.
Wishing you all a very HAPPY NEW YEAR
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
SPECIAL MESSAGE
Respected Seniors and Dear Colleagues,
Greetings from the DOS Executive!
It gives me great pleasure to write this Special Message in this issue of the DOS
Times.
Congratulations go out to our perseverant Secretary, Prof. Vanathi, our energetic
Treasurer, Dr Vipul Nayar and the entire Executive for the proceedings thus far. The
successful conduct of the midterm WinterDOS Conference was a matter of great pride
– bringing the event back to the India Habitat Centre was appreciated by all.
The innovative combination of the DOS Training Programme with the WinterDOS
this year was a great idea and may well become the standard practice for the future.
ϐ
ǡ ǡ Dr. Rishi Mohan
discussions, posters, videos and photography contests. The sociocultural event at
the Kingdom of Dreams was a one-of-a-kind experience for those who attended and
broke all records for the WinterDOS dinner attendance. But for a national level monetary event, with an unforeseen
immediate fallout, the participation would have been even more enthusiastic. Thanks are due to all who contributed
to the success of the Meeting.
ǡ Ǧ
ϐ
ǡ
of the DOS are evincing a renewed interest. An effort is being made to consciously make the discussions more clinically
oriented and less didactic in nature.
Concrete proposals have emerged from the deliberations of the DOS House, the Academic, Research and Fellowship,
the DayCare and the TPA SubCommittees and some positive actions are underway.
Preparations for the iDOS-COSL Meeting in Colombo, SriLanka from December 22-24, 2016 have been
ϐǤ
ϐ
Ǥ Ǥ
Ǥ ϐ
from our SriLankan counterparts. All participants are looking forward to get together on this wonderful academic and
Ǧϐ Ǩ
ϐ World Society of Paediatric
Ophthalmology and Strabismus for the 4th World Congress (WCPOS) in December 2017, with the ensuing loss of
ǡ ϐ
Ǥ
As they say, “Persevere in virtue and diligence” (Author-Titus Livy). We should plod on and pledge to make all
efforts for continuously raising the bar, to ensure that the DOS maintains its position under the sun.
With Warm Regards,
Dr. Rishi Mohan
President, DOS
&
Director, MM Eyetech Institute of Ophthalmology,
Lajpat Nagar-3, New Delhi.
www. dos-times.org 9
RESEARCH METHODOLOGY
SYSTEMATIZING OPHTHALMOLOGY AND
COPING WITH THE CHALLENGES
Archita Singh, Radhika Tandon
The concept of evidence based medicine is appealing to all. Clinicians like to have
ϐ
Ǥ
ǡ
information at hand when taking decisions on diagnosis, treatment and surgical
planning is the holy grail of modern times. Systematic Reviews
The concept of evidence based medicine is
Ǥ
ϐ
guideline to follow in day to day practice. Having
systematic, accurate information at hand when
taking decisions on diagnosis, treatment and
surgical planning is the holy grail of modern
times. Another view is that traditional reliance on experience RCTs
and expertise remains a key aspect of patient care which
cannot be fully replaced by mathematical distillation of data
or statistical calisthenics. Needless to say we need a balance of
both. Observational Studies
One requires a combination of a particular physician’s
or surgeon’s judiciousness in decision making for care of an
individual patient and a compendium of knowledge to provide Case Series, Case Reports,
a useful database to fall back on for reference and consultation. Anecdotal findings, Opinions, Ideas
Even if one were to have access to the best modern or most
ϐ
plans or guidelines, one still needs to judiciously apply one’s
mind integrating clinical judgement based on experience Figure 1: The knowledge pyramid
and processing patient values in the light of best research
information available to arrive at practical decisions and literature but an active effort to further build on the published
proceed with the clinical responsibility of patient care. work by gathering the publications, performing a critical
analysis to answer the study question and derive the required
This new approach of relying on strong research based conclusion. Though labelled as a review, it characteristically
practice guidelines supported by high quality clinical research
ϐ
is a welcome change, but does pose new challenges for all form of research offering a reliable alternative to conducting a
concerned. This movement can go forward effectively if the fresh study which would involve further resources in terms of
academic community continues to generate high quality time, logistics and funds.
clinical research papers published in accessible journals and
at the same time also manages to disseminate the information Needless to say that whatever the literature may offer,
to maintain a reliable level of knowledge among practising we do have to be fully cognizant of the individual needs of
ophthalmologists to ably distil the information in routine
ϐ
working conditions. ϐ
Ǥ
available nowadays combined with numerous discussion and
It is accepted that there are different levels of evidence advice received from various professional platforms such as
and in the knowledge pyramid systematic reviews stand at conferences, guidance and comments exchanged over social
the pinnacle followed by randomized controlled clinical trials, media etc pose a fresh challenge as also the fear of unforced
observational studies (cohort, case-control and cross sectional), or forced errors, negligence and litigation looming over our
ǡ
ǡ
ϐǡ heads. Acting in good faith keeping in view the best available
in descending order of strength (Figure 1). information at hand is the sensible approach and access
to systematic reviews and other forms of reliable evidence
ϐ
strengthens our hand.
opinion and decision making it is worth revising the main facets
of this form of establishing evidence to support clinical practice.
ϐ
A systematic review is, as the name suggests, a type of literature pattern must be followed to reach the desired goal and achieve
review that is not merely a collection and synopisis of available
www. dos-times.org 11
RESEARCH METHODOLOGY
Table 1: Sample of Systematic Reviews in Ophthalmology
(Few Examples from the Cochrane Database of Systematic Reviews)
S. no. Systematic Review Author (Year) Remarks
1. Prophylactic non-steroidal Lim BX et al (2016) Ȉ Included 34 studies
Ǧϐ Ȉ Utilized the GRADE approach to analyse#
prevention of macular edema Ȉ
Ǧϐ
after cataract surgery1 surgery macular oedema. But the effect on visual functions
and quality of life remains uncertain.
2. Patching for corneal abrasion2 Lim CL et al (2016) Ȉ Included 12 studies
Ȉ Utilized GRADE to assess for certainty of evidence
Ȉ Patching may not improve healing or decrease pain
Ȉ Recommended better trials to assess effectiveness of
patching in larger abrasions
3. Over the counter (OTC) Pucker AD et al Ȉ Included 43 RCTs
ϐ
(2016) Ȉ ǯ ϐ
syndrome3 Ȉ But evidence seems to be low due to inconsistencies in the
study designs and reporting of the results
4. Interventions for central serous Salehi M et al (2015) Ȉ Included 25 studies
chorioretinopathy: a network Ȉ ϐ
meta-analysis4 Ȉ Of the available therapeutic options PDT or micro-pulse laser
treatment may be helpful but future studies are required.
5. Conjunctival autograft for ϐ Ȉ Include 13 studies
pterygium5 (2016) Ȉ Lower risk of recurrence following conjunctival autograft as
compared to amniotic membrane transplant
6. Interventions for trachoma Burton M et al (2015) Ȉ Modest improvement following intervention for trichiasis
trichiasis6 was seen
Ȉ Full thickness tarsal plate incision with rotation was found
to be preferred technique
Ȉ
ϐ
recurrence rate
7. Anti-vascular endothelial Virgili G et al (2014) Ȉ Included 18 studies
growth factor for diabetic Ȉ ϐ
Ǧ
macular oedema7 ϐ
ϐ
Ǥ
8. Interventions for strabismic Taylor K et al (2014) Ȉ Included 3 RCTs
amblyopia8 Ȉ Occlusion along with appropriate refractive correction was
ϐ
Ǥ
Ȉ The role near activities was not clear
9. Ǧ ϐ Eldaly MA et al (2014) Ȉ Included 5 studies
surgery versus trabeculectomy Ȉ IOP control was better with trabeculectomy as compared to
for open-angle glaucoma9 viscocanalostomy
Ȉ Results for deep sclerectomy were inconclusive
10. Deep anterior lamellar Keane M et al (2014) Ȉ There was no difference with regard to the uncorrected
keratoplasty versus penetrating visual acuity, keratometry and graft survival in penetrating
keratoplasty for treating keratoplasty versus DALK
keratoconus10 Ȉ Rejection was more in penetrating keratoplasty versus DALK
(GRADE: Moderate evidence)
#GRADE Approach: The Grades of Recommendation, Assessment, Development and Evaluation Working Group has developed a system
for grading the quality of evidence. (GRADE Working group 2004)11
Dr. Rajendra Prasad Centre for Ophthalmic Sciences,AIIMS, New Delhi
Dr.Archita Singh MD, Prof. Radhika Tandon MD, DNB, FRCOphth
12 DOS TIMES - NOVEMBER-DECEMBER 2016
RESEARCH METHODOLOGY
Identify the need for a systematic review and its impact on the current practices Demands better application of mind
ϐ
the holy grail of modern medicine
and deliver the greatest good in the
circumstances encountered.
Framing the Research Question – Identify the main goal of the Systemic Review REFERENCES
Designing the Protocol for the Review 1. Lim BX, Lim CHL, Lim DK, Evans JR,
Bunce C, Wormald R. Prophylactic non-
Inclusion Review of Selecting Quality Data Ǧϐ
and literature studies / assessment Extraction the prevention of macular oedema after
research cataract surgery. Cochrane Database of
Exclusion work for of the Systematic Reviews 2016, Issue 11. Art.
criteria studies No.: CD006683.
Data Evaluation and Analysis 2. Turner A, Rabiu M. Patching for corneal
abrasion. Cochrane Database of
Presentation of the Conclusions and the Results Systematic Reviews 2006, Issue 2. Art.
No.: CD004764.
Recommendations following the Systematic Review
3. Pucker A, Marrone M, Nichols JJ. Over
Figure 2: How to write a Systemic Review- Step by Step
ȋ Ȍ ϐ
for dry eye syndrome (Protocol).
Individualized Evidence the objective. A simple Cochrane Database of Systematic
Care ϐ
Reviews 2012, Issue 3. Art. No.:
Knowldege the process is illustrated CD009729.
Clinical Experience Extra Skills in (Figure 2). A few
Clinical Practice illustrative examples of 4. Salehi M, Wenick AS, Law HA, Evans JR,
Expertise Better evidence than systematic reviews listed Gehlbach P. Interventions for central
Proficiency traditionally used in (Table 1) indicate the serous chorioretinopathy: a network
Judgement kind of information that meta-analysis. Cochrane Database of
can be obtained and Systematic Reviews 2015, Issue 12. Art.
Thoughtful identification of consulted. No.: CD011841.
patient's concerns
As with all published ͷǤ ϐ ǡ ǡ ǡ
Compassionate application work, one must read, Kuo IC. Conjunctival autograft for
Patients Risks imbibe and process pterygium. Cochrane Database of
the information with Systematic Reviews 2016, Issue 2. Art.
Patients Privileges reference to context and No.: CD011349.
Patient Preferences apply the knowledge
gained with reference 6. Burton M, Habtamu E, Ho D, Gower EW.
to the particular patient Interventions for trachoma trichiasis.
or clinical scenario Cochrane Database of Systematic
encountered. Reviews 2015, Issue 11. Art. No.:
CD004008.
(Figure 3) Better
Healthcare Provision 7. Virgili G, Parravano M, Menchini F,
Evans JR. Anti-vascular endothelial
growth factor for diabetic macular
oedema. Cochrane Database of
Systematic Reviews 2014, Issue 10. Art.
No.: CD007419.
8. Taylor K, Elliott S. Interventions for
strabismic amblyopia. Cochrane
Database of Systematic Reviews 2011,
Issue 8. Art. No.: CD006461.
9. Eldaly MA, Bunce C, ElSheikha OZ,
Ǥ Ǧ ϐ
surgery versus trabeculectomy for
open-angle glaucoma. Cochrane
Database of Systematic Reviews 2014,
Issue 2. Art. No.: CD007059.
10. Keane M, Coster D, Ziaei M, Williams
K. Deep anterior lamellar keratoplasty
versus penetrating keratoplasty
for treating keratoconus. Cochrane
Database of Systematic Reviews 2014,
Issue 7. Art. No.: CD009700.
11. Web reference :http:// training.
cochrane.org/path/grade-approach-
evaluating-quality-evidence-pathway
Figure 3: Balancing of clinical knowledge and evidence based
machine
Financial Interest: ϔ
Ȁ
Ǥ
www. dos-times.org 13
CORNEA
DRY EYE DISEASE AFTER REFRACTIVE SURGERY-
CURRENT SCENARIO
Saranya Devi K. Noopur Gupta, M. Vanathi
LASIK has been the most popular refractive surgery The ocular surface and the lacrimal gland work in liaison as a
in past two decades. Recent advances in the
ϐ Ǥ
technology such as shift to blade-free LASIK from sensory nerves from the ocular surface interact with the efferent
the use of microkeratome, has made this procedure
ϐ
safe, easy and effective. The overall satisfaction secretion. Any factor that affects this neuronal interaction will
rate following LASIK has been reported to be as ϐ
Ǥ
high as 95%1-3. Despite such high satisfaction rate and excellent
ϐ
refractive outcomes, complications do occur with LASIK. the epithelium19.
Dry eye disease (DED) is the most common complication Various theories have been proposed to explain the
encountered after LASIK with the incidence ranging from 20- occurrence of DED after LASIK the most important contributory
40% at 6 months after the surgery4. factor being the iatrogenic nerve damage. Disruption of the sub-
The International Dry Eye Work Shop (DEWS) has recently basal nerve plexus and stromal nerves have been reported to
ϐ Dz
ϐ
Ǥ
ocular surface that results in symptoms of discomfort, visual Other factors include loss of conjunctival goblet cells20, LASIK
ǡ ϐ induced change in the corneal shape21 Ǧϐ
the ocular surface. It is accompanied by increased osmolarity
Ǥ ϐ
ϐ ϐ
dz5. DED ϐ
ϐ ǡ
can cause ocular discomfort, visual disturbances thereby resulting in dry eye symptoms22.
ϐ
6,7.
Chronic dry eye disease can even result in the regression of CLINICAL FEATURES
refractive error8. The clinical features of DED include symptoms such as
EPIDEMIOLOGY Various recent advances in the technology irritation, burning sensation,
foreign body sensation and
Different studies have such as shift to the blade-free LASIK from visual disturbances. Clinical
shown variable results regarding signs of DED after refractive
the incidence of DED after the use of microkeratome, has made surgery can be divided into
LASIK. Majority of the patients this procedure safe, easy and effective. ͳȌ ϐ
develop dry eyes in the early
ʹȌ ϐ
few months after the surgery. The overall satisfaction rate following and 3) diminished corneal
Then the symptoms improve at LASIK has been reported to be as high sensation.
around 6-12 months after the as 95%. Despite such high satisfaction
surgery9. The incidence of dry TEAR FILM PRODUCTION &
eye symptoms in the immediate rate and excellent refractive outcomes, STABILITY
post-operative period is as complications do occur with LASIK. Dry Various studies have
high as 95 % which gradually
declines to about 60 % at 1 eye disease (DED) is the most common reported decrease in the tear
month after the surgery10-14. At complication encountered after LASIK ϐ
LASIK. The effect of LASIK on
6 months post-operative period, with the incidence ranging from 20-40% tear function was evaluated in a
the incidence varies from prospective study where 96 eyes
12%-48 %15-17. The incidence at 6 months after the surgery of 58 patients were included.
of DED after PRK is similar to This study documented decrease
that after LASIK, except in the in Schirmer I values at 1 month post-LASIK and decrease in tear
immediate post-operative period. Immediately after PRK, break up time (TBUT) at 1 day and 1 week post-LASIK. Another
patients experience increased ocular surface discomfort as the study by Polunin et al.23 followup documented the decrease in
epithelium heals18. the corneal barrier function following PRK and LASIK, with the
PATHOPHYSIOLOGY recovery being more delayed after LASIK than after PRK. Lee
ϐ
The pathophysiology of DED is multifactorial in origin. ϐ
www. dos-times.org 15
CORNEA
at 3 months followup in LASIK patients as recovery in central corneal sensitivity at with superior hinge46 leading to increased
compared to the PRK patients. Nejima et 3 months after the surgery as compared risk of dry eyes after the surgery.
al24 documented decrease in the epithelial to 86.2% in patients with myopia more However few other studies revealed no
barrier function, tear secretion and tear than -9D. Mean time for recovery of such difference in corneal sensation with
ϐ Ǥ corneal sensation to preoperative levels different hinge location47.
They also reported that the epithelial has been reported to be around 6-9
barrier dysfunction persisted for longer months after the surgery. Other studies ϐ
periods in LASIK patients as compared to have documented this recovery time to be of other intra-operative parameters such
PRK patients. as early as 3 weeks37 to as long as 12-16 ϐ ǡ ϐ
ǡ
months38 after LASIK. ablation depth over the development of
Effect of LASIK in hyperopic eyes post-LASIK dry eyes. Various studies48,49
ϐ
PRE-OPERATIVE RISK FACTORS have established the positive correlation
evaluated in a study25 which showed between these parameters and the post-
decrease in tear volume at 3 months after It is imperative to screen the patients procedure dry eye disease while few
LASIK, but the tear volume had increased for refractive surgeries in order to studies50 found no such association. The
to preoperative levels by 6 months. improve the overall success rate, patient ϐǡ
Various studies26 have reported that satisfaction and also to decrease the ϐǡ
this decrease in Schirmer’s, TBUT and incidence of post-operative complications preserve more corneal nerves, thereby
basal tear secretion after LASIK surgery such as dry eye disease. Pre-operative reducing the risk of dry eye disease. The
might persist for months or even longer. examination must include assessment of
ϐ
Another study reported that only 0.04% tear meniscus, tear quality, tear break-up such as the use of microkeratome and
(8 of 20,745) post-PRK patients and time, Schirmer testing and ocular surface femtosecond laser has also been studied,
0.25% (21 of 8528) post-LASIK patients staining. the results of which are mixed. Salomao
had dry eye symptoms severe enough to et al reported increased evidence of
require the placement of punctal plugs27. The most important risk factor postoperative dry eye disease in patients
Several other studies have reported the development of dry eye disease is
ϐǢ ǡ
increase in TGF beta 1 concentration in pre-existing dry eyes. Such patients et al51 found no difference between the
ϐ 28 and after PRK, should be treated appropriately and techniques.
ǦȽ29, IL-630ǡ
ǦȾǡ
31, proper counselling should be given
PDGF-BB32 has been reported. regarding the post-operative outcomes. MANAGEMENT
Any ocular surface disease should
CORNEAL SENSATION be treated appropriately before the Preoperative screening and following
refractive procedure. Aggressive ocular adequate precautions of the patients is
Corneal sensitivity is a crucial factor surface treatment before LASIK has been essential to prevent the occurrence of dry
to maintain the normal corneal structure ϐ
eye disease after the refractive surgeries.
and function. The afferent sensory nerves dry eye symptoms after the surgery39. Those at risk should be counselled
of the ocular surface originate from the Cyclosporine or corticosteroid therapy regarding the postoperative exacerbation
ophthalmic division of the trigeminal can also be considered to treat the of symptoms and to have realistic
nerve. These nerves then penetrate the ϐ 40. expectations in terms of visual outcome.
peripheral cornea to form the sub-basal Ocular surface health is essential before
nerve plexus from where terminal nerve Another important risk factor is the surgery, which can be achieved by
endings reach the epithelium. Refractive contact lens use as long term contact the use of lubricants, cyclosporine or
procedures such as PRK and LASIK cause lens use can result in the release of corticosteroids.
nerve damage resulting in decreased basal ϐ
ǡ
ϐ ǡ
ϐ Postoperative management of the
can even result in dreadful complications instability41.Other risk factors include ocular surface is also important. Frequent
such as neurotrophic keratitis or sterile ocular allergy42, collagen vascular Ǧ ϐ
52
corneal melts33,34. diseases43, Asian ethnicity44, diabetes45 has been promising, especially in the early
and female sex. postoperative period. Punctal plugs53,54
Multiple studies have shown may increase tear volume in cases of
decrease in corneal sensitivity after INTRA-OPERATIVE RISK FACTORS ϐ
Ǥ
LASIK procedure35. Bandage soft contact lenses may be used
Post refractive surgery DED can in selected patients with normal tear
Campos et al36 evaluated the corneal occur due to various intra operative production to reduce surface irritation
sensation in patients undergoing PRK changes induced in the ocular surface. while corneal nerves regenerate.
and found that about 95.7% of the ǡ Ǧ ϐ For patients who develop persistent
patients with myopia less than -6.5 D had
ϐ
Dr. Rajendra Prasad Centre for Ophthalmic Sciences,AIIMS, New Delhi
Dr. Saranya Devi K MD, DNB Dr. Noopur Gupta MS, DNB, PhD Prof. M.Vanathi MD
16 DOS TIMES - NOVEMBER-DECEMBER 2016
CORNEA
neurotrophic keratopathy after LASIK, it 9. Shtein RM. Post-LASIK dry eye. Expert review of 36. Campos M, Hertzog L, Garbus JJ, McDonnell
is useful to pursue traditional treatment Ǥ ʹͲͳͳǢǣͷͷǦͺʹǤ PJ. Corneal sensitivity after photorefractive
modalities for neurotrophic keratopathy,
Ǥ
ͳͻͻʹǢ ͳͳͶǣͷͳȂͷͶǤ
Ǧ ϐ
10. Yu EY, Leung A, Rao S, Lam DS. Effect of laser in situ
tears, punctal occlusion, bandage contact keratomileusis on tear stability. Ophthalmology. 37. Chuck RS, Quiros PA, Perez AC, McDonnell PJ.
lenses, and tarsorrhaphy. ʹͲͲͲǢ ͳͲǣʹͳ͵ͳȂ͵ͷǤ Corneal sensation after laser in situ keratomileusis. J
Ǥ ʹͲͲͲǢ ʹǣ͵͵Ȃ͵ͻǤ
Adjuvants such as topical 11. Melki SA, Azar DT. LASIK complications: etiology,
cyclosporine55,56 and omega-3 fatty management, and prevention. Surv Ophthalmol. 38. Mian SI, Shtein RM, Nelson A, Musch DC. Effect of
acids57 ϐ
ʹͲͲͳǢ ͶǣͻͷȂͳͳǤ hinge position on corneal sensation and dry eye after
in post-LASIK patients, in increasing the laser in situ keratomileusis using a femtosecond
corneal sensitivity and achieving faster 12. Hovanesian JA, Shah SS, Maloney RK. Symptoms Ǥ
Ǥ ʹͲͲǢ ͵͵ǣͳͳͻͲȂͻͶǤ
visual recovery. of dry eye and recurrent erosion syndrome after
Ǥ
Ǥ ʹͲͲͳǢ 39. Albietz JM, McLennan SG, Lenton LM. Ocular surface
SMILE VS LASIK-IS IT BETTER? 27:577–84. management of photorefractive keratectomy and
Ǥ
Ǥ ʹͲͲ͵Ǣ
Small-incision lenticule extraction ͳ͵Ǥ ǡ
ǡ ǡ ϐ Ǥ
19:636–44.
(SMILE) is a major advancement in of laser in situ keratomileusis on tear production,
the refractive surgery which was clearance, and the ocular surface. Ophthalmology. ͶͲǤ ϐ ǡ ǡ ǡ Ǥ
Dzϐdz
ʹͲͲͳǢ ͳͲͺǣͳʹ͵ͲȂ͵ͷǤ randomized, double-masked, placebo-controlled,
which an intrastromal lenticule is cut multicenter comparison of loteprednol etabonate
by a femtosecond laser and manually 14. Toda I, Asano-Kato N, Komai-Hori Y, Tsubota K. ophthalmic suspension, 0.5%, and placebo for
extracted through a peripheral corneal Dry eye after laser in situ keratomileusis. Am J treatment of keratoconjunctivitis sicca in patients
tunnel incision. SMILE causes lesser Ǥ ʹͲͲͳǢ ͳ͵ʹǣͳȂǤ
Ǥ
Ǥ ʹͲͲͶǢ
degree of damage to the cornea and 138:444–57.
corneal nerves, and may therefore result 15. De Paiva CS, Chen Z, Koch DD, et al. The incidence
in fewer complications and reduced and risk factors for developing dry eye after myopic ͶͳǤ ò ǡ G
ǡ ǡ Ǥ
symptoms of dry eye. Ǥ
Ǥ ʹͲͲǢͳͶͳǣͶ͵ͺȂͶͷǤ Comparative Analysis of Tear Film Levels of
ϐ
Ǥ
Li et al.58, compared the corneal 16. Shoja MR, Besharati MR. Dry eye after LASIK for Ǥ ʹͲͳǢͶͳǣͶͶͳǦǤ
sensitivity and dry eye following SMILE myopia: incidence and risk factors. Eur J Ophthalmol.
and FS-LASIK surgery and found that ʹͲͲǢͳǣͳȂǤ 42. Bielory BP, O’Brien TP. Allergic complications with
corneal sensitivity was less reduced and laser-assisted in-situ keratomileusis. Curr Opin
thus better in patients that underwent 17. Denoyer A, Landman E, Trinh L, et al. Dry eye disease Ǥ ʹͲͳͳǢͳͳǣͶͺ͵ȂͻͳǤ
SMILE at all postoperative time intervals after refractive surgery: comparative outcomes of
compared to those patients that small incision lenticule extraction versus LASIK. 43. Simpson RG, Moshirfar M, Edmonds JN, et al. Laser
underwent FS-LASIK. Ǥ ʹͲͳͷǢͳʹʹǣͻȂǤ in situ keratomileusis in patients with collagen
vascular disease: a review of the literature. Clin
Another recent study59 has 18. Stephenson CG, Gartry DS, O’Brart DP, et al. Ǥ ʹͲͳʹǢǣͳͺʹȂ͵Ǥ
demonstrated that SMILE resulted in a Photorefractive keratectomy. A 6-year follow-up
lesser degree of dry eye disease and a Ǥ Ǥ ͳͻͻͺǢͳͲͷǣʹ͵ȂͺͳǤ 44. Albietz JM, Lenton LM, McLennan SG. Dry eye after
faster recovery of tear function compared LASIK: comparison of outcomes for Asian and
to FS-LASIK in the short-term following 19. Lee HK, Lee KS, Kim HC, et al. Nerve growth factor
Ǥ Ǥ ʹͲͲͷǢ ͺͺǣͺͻȂͻǤ
surgery in those patients with no concentration and implications in photorefractive
preexisting dry eye disease. keratectomy vs laser in situ keratomileusis. Am J 45. Fraunfelder FW, Rich LF. Laser-assisted in situ
ʹͲͲͷǢ ͳ͵ͻǣͻͷȂͳǤ keratomileusis complications in diabetes mellitus.
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20. Shin SY, Lee YJ. Conjunctival changes induced by
1. Brunette I, Gresset J, Boivin JF, et al. Functional LASIK suction ring in a rabbit model. Ophthalmic 46. Donnenfeld ED, Solomon K, Perry HD, et al. The
outcome and satisfaction after photorefractive Ǥ ʹͲͲǢ ͵ͺǣ͵Ͷ͵ȂͶͻǤ effect of hinge position on corneal sensation and dry
keratectomy. Part 2: survey of 690 patients. Ǥ Ǥ ʹͲͲ͵ǢͳͳͲǣͳͲʹ͵ȂʹͻǤ
Ǥ ʹͲͲͲǢͳͲǣͳͻͲȂͻǤ 21. Solomon R, Donnenfeld ED, Perry HD. The effects of
Ǥ
Ǥ ʹͲͲͶǢ ʹǣ͵ͶȂ 47. Mian SI, Li AY, Dutta S, et al. Dry eyes and corneal
2. O’Doherty M, O’Keeffe M, Kelleher C. Five year follow 44. sensation after laser in situ keratomileusis with
up of laser in situ keratomileusis for all levels of
ϐ
Ǥ
Ǥ ʹͲͲǢͻͲǣʹͲȂʹ͵Ǥ 22. Lee JB, Ryu CH, Kim J, Kim EK, Kim HB. Comparison ǡ ǡ ϐ
Ǥ
ϐ
Ǥ ʹͲͲͻǢ͵ͷǣʹͲͻʹȂͻͺǤ
3. Solomon KD, Fernandez de Castro LE, Sandoval photorefractive keratectomy and laser in situ
HP, et al. LASIK world literature review: quality Ǥ
Ǥ ʹͲͲͲǢ 48. Donnenfeld ED, Ehrenhaus M, Solomon R, et al.
of life and patient satisfaction. Ophthalmology. 26:1326–31. Effect of hinge width on corneal sensation and dry
ʹͲͲͻǢͳͳǣͻͳȂͲͳǤ eye after laser in situ keratomileusis. J Cataract
23. Polunin GS, Kourenkov VV, Makarov IA, Polunina EG.
Ǥ ʹͲͲͶǢ͵ͲǣͻͲȂͻǤ
4. Chao C, Golebiowski B, Stapleton F. The role of The corneal barrier function in myopic eyes after
corneal innervation in LASIK-induced neuropathic laser in situ keratomileusis and after photorefractive 49. Bragheeth MA, Dua HS. Corneal sensation after
Ǥ
ʹͲͳͶǢͳʹǣ͵ʹȂͶͷǤ keratectomy in eyes with haze formation. J Refract myopic and hyperopic LASIK: clinical and confocal
ͳͻͻͻǢ ͳͷǣ ʹʹͳȂʹͶǤ
Ǥ
Ǥ ʹͲͲͷǢͺͻǣͷͺͲȂ
ͷǤ ϐ
ϐ
85.
ǣ ϐ ϐ
24. Nejima R, Miyata K, Tanabe T, et al. Corneal barrier
Subcommittee of the International Dry Eye
ǡ ϐ ǡ
50. Salomao MQ, Ambrosio R Jr, Wilson SE. Dry eye
Ǥ
Ǥ ʹͲͲǢ ͷǣͷȂͻʹǤ after photorefractive keratectomy and laser in situ associated with laser in situ keratomileusis:
Ǥ
ʹͲͲͷǢ ͳ͵ͻǣͶȂͳǤ mechanical microkeratome versus femtosecond
6. Miljanovic B, Dana R, Sullivan DA, et al. Impact of dry Ǥ
Ǥ ʹͲͲͻǢ͵ͷǣͳͷȂͲǤ
eye syndrome on vision-related quality of life. Am J 25. Albietz JM, Lenton LM, McLennan SG. Effect of laser
Ǥ ʹͲͲǢͳͶ͵ǣͶͲͻȂͳͷǤ ϐ 51. Patel SV, McLaren JW, Kittleson KM, et al. Subbasal
Ǥ
Ǥ ʹͲͲʹǢ ͳͺǣͳͳ͵Ȃʹ͵Ǥ nerve density and corneal sensitivity after laser
7. Paulsen AJ, Cruickshanks KJ, Fischer ME, et al. Dry in situ keratomileusis: femtosecond laser vs
eye in the Beaver Dam Offspring Study: prevalence, 26. Benitez-del-Castillo JM, del Rio T, Iradier T, et al. mechanical microkeratome. Arch Ophthalmol.
risk factors, and health-related quality of life. Am J Decrease in tear secretion and corneal sensitivity ʹͲͳͲǢͳʹͺǣͳͶͳ͵ȂͳͻǤ
Ǥ ʹͲͳͶǢͳͷǣͻͻȂͺͲǤ Ǥ Ǥ ʹͲͲͳǢ
20:30–2. 52. Lenton LM, Albietz JM. Effect of carmellose-
8. Albietz JM, Lenton LM, McLennan SG. Chronic dry ϐ
eye and regression after laser in situ keratomileusis 27. Hammond MD, Madigan WP Jr, Bower KS. Refractive after laser in situ keratomileusis. J Refract Surg.
Ǥ
Ǥ ʹͲͲͶǢ͵ͲǣͷȂͺͶǤ surgery in the United States army, 2000–2003. ͳͻͻͻǢͳͷǣ ʹʹȂ ʹ͵ͳǤ
Ǥ ʹͲͲͷǢͳͳʹǣͳͺͶȂͳͻͲǤ
53. Alfawaz AM, Algehedan S, Jastaneiah SS, et al.
28. Long Q, Chu R, Zhou X, et al. Correlation between ϐ
TGF-B1 in tears and corneal haze following LASEK eyes after laser in situ keratomileusis for myopia.
Ǧ Ǥ
Ǥ ʹͲͲǢ ʹʹǣͲͺȂͳʹǤ Ǥ ʹͲͳͶǢ͵ͻǣʹͷȂʹǤ
29. Vesaluoma M, Teppo AM, Grönhagen-Riska C, Tervo 54. Yung YH, Toda I, Sakai C, et al. Punctal plugs for
T. Increased release of tumour necrosis factor-alpha treatment of post-LASIK dry eye. Jpn J Ophthalmol.
ϐ
ʹͲͳʹǢͷǣʹͲͺȂʹͳ͵Ǥ
Ǥ
Ǥ ͳͻͻǢ ͺͳǣͳͶͷȂͻǤ
55. Peyman GA, Sanders DR, Batlle JF, et al. Cyclosporine
30. Malecaze F, Simorre V, Chollet P, et al. Interleukin-6 0.05%ophthalmic preparation to aid recovery from
ϐ
loss of corneal sensitivity after LASIK. J Refract Surg.
Ǥ Ǥ ͳͻͻǢ ʹͲͲͺǢʹͶǣ͵͵ȂͶ͵Ǥ
16:580–87.
56. Ursea R, Purcell TL, Tan BU, et al. The effect of
31. Vesaluoma M, Teppo AM, Grönhagen-Riska C, Tervo cyclosporine A (Restasis) on recovery of visual
T. Release of TGF-beta 1 and VEGF in tears following
Ǥ
Ǥ ʹͲͲͺǢʹͶǣͶ͵Ȃ
Ǥ Ǥ ͳͻͻǢ 76.
16:19–25.
57. Ong NH, Purcell TL, Roch-Levecq AC, et al. Epithelial
32. Vesaluoma M, Teppo AM, Gronhagen-Riska C, Tervo healing and visual outcomes of patients using
T. Platelet-derived growth factor-BB (PDGF-BB) in omega-3 oral nutritional supplements before and
ϐǣ
after photorefractive keratectomy: a pilot study.
healing following photorefractive keratectomy. Curr Ǥ ʹͲͳ͵Ǣ͵ʹǣͳȂͷǤ
Ǥ ͳͻͻǢ ͳǣͺʹͷȂ͵ͳǤ
58. M. Li, J. Zhao, Y. Shen et al., “Comparison of dry
33. Pe´rez-Santoja JJ, Sakla HF, Cardona C, et al. Corneal eye and corneal sensitivity between small incision
sensitivity after photorefractive keratectomy and lenticule extraction and femtosecond LASIK for
laser in situ keratomileusis for low myopia. Am J myopia,” PloS ONE, vol. 8, no. 10, Article ID e77797,
ͳͻͻͻǢ ͳʹǣͶͻȂͷͲͶǤ 2013.
34. Matsui H, Kumano Y, Zushi I, et al. Corneal sensation 59. Bingjie Wang, Rajeev K. Naidu, Renyuan Chu, Jinhui
after correction of myopia by photorefractive Dai, Xiaomei Qu, and Hao Zhou, “Dry Eye Disease
keratectomy and laser in situ keratomileusis. J following Refractive Surgery: A 12-Month Follow-Up
ʹͲͲͳǢ ʹǣ͵ͲȂ͵Ǥ of SMILE versus FS-LASIK in High Myopia,” Journal
of Ophthalmology, vol. 2015, Article ID 132417, 8
35. Ambrosio R, Tervo T, Wilson S. LASIK-associated pages, 2015.
dry eye and neurotrophic epitheliopathy:
pathophysiology and strategies for prevention and
Ǥ
Ǥ ʹͲͲͺǢ ʹͶǣ͵ͻȂͶͲǤ
Financial Interest: ϔ
Ȁ
Ǥ
www. dos-times.org 17
CORNEA
NEUROTROPHIC KERATOPATHY
Namrata Kabra, Namrata Majhi
Schwannoma (neurilemmoma) is a benign tumor He was advised MRI with contrast which showed dumbbell
of the peripheral nerve arising from Schwann cells shaped mass leison in left CP angle cistern, lateral pontine
that form the neural sheath. These are tumors of cistern with extension to left middle cranial fossa with mass
adulthood usually presenting between 20 to 70 effects on brainstem, left cerebellum and fourth ventricle, and
years of age. Schwannomas of the cranial nerves are left temporal lobe suggestive of left trigeminal schwannoma.
usually benign, involving the vestibular nerve and, He underwent excisional biopsy under GA. Histopothology
less often, the trigeminal nerve. Benign schwannoma of the
ϐ
Ǥ Ǧ
trigeminal nerve comprises only 0.2% to 0.4% of all intracranial showed no residual tumour.
tumors and primarily arises in the gasserian ganglion. Malignant Diagnosis of Mackie’s stage I neurotrophic keratopathyi,ii
schwannomas of the cranial nerves are much less common. in left eye was made. He was advised to instil 1% CMC
Schwannoma of ophthalmic interest is rare. We report a rare (preservative free) hourly. On review after 3wks, schirmer I & II
case of a 15-year-old male with trigeminal nerve Schwannoma. were 5mm and 6mm respectively. Patient was symptomatically
The mass was surgically removed by excisional biopsy and was better, but no improvement was seen clinically. Trial of
ϐ
Ǥ dissolvable collagen punctual plugs was given. At next followup
diagnosis of Grade I neurotrophic keratopathy was made and visit improvement noticed. SPKs decreased and surface
was managed accordingly. lusture improved. No complain of epiphora noted. Hence,
Synthetic extended temporary punctal plugs (90 day plugs)
CASE REPORT Ǥ ϐ
Ǥ
15 years old male improved to 6/6 over a period of 4 months. Meanwhile surgical
presented to our institution
with chief complaints of reduced Paediatric schwannoma of trigeminal origin exploration was planned in
vision, redness, watering and case the condition worsens in
though rare can lead to corneal anaesthesia subsequent followups.
photophobia in his left eye since and hence neurotrophic keratopathy. CLINICALLY &
1 year which got aggravated History itself is a clue towards diagnosis. SYMTOMATICALLY
in last 3 months which was
gradually progressive. His BCVA Therapeautic dilemma is a real challenge for Review of Literature
was 6/6 and 6/120 in right
and left eye respectively. There ophthalmologists. Early commencement of Schwannomas are slow-
was no globe displacement or ocular treatment can be rewarding in halting
growing typically encapsulated
proptosis. Ocular movements the progression of keratopathy and avoiding tumors composed of
were full and free in all the ocular complications. “Sensations not just
directions. The pupillary differentiated Schwann cells,
the primary class of peripheral
glial cells1,2. These are most
reactions and colour vision were take away tear but also cheer, with prompt common in the 20- to 50-year-
WNL. On Slit lamp examination, old age group, but may occur at
he had diffuse SPKs grd 3 in treatment let’s overcome this fear.” any age. No frequency variation
interpalpebral area and grd according to sex has been
1 in rest part of the cornea in the left eye. Corneal sensation ϐ3. A review of the literature suggests that in the post-
was ABSENT in the left eye. Schirmer’s I & II showed 10mm & CT era, very few cases of paediatric schwannoma have been
31 mm in right eye respectively, and 5mm & 8mm in left eye reported4,5.
respectively. Thus lacrimal secretion was found to be reduced Complete excision is the treatment of choice for
ȋϐ εȌǤ Ǥ ϐ
ǡ ϐǡ ǡ
were WNL. optic neuropathy6-8. Histologically, schwannomas are usually
He had a past history of facial numbness on right side of encapsulated with alternating cellular schwann-cell rich
his face and impaired hearing, for which he consulted a local Antoni-A areas and less cellular and myxoid Antoni-B areas9,
neurosurgeon 1 yr back. As per his reports, he had B/L horizontal which immunohistochemically stain strongly for S-100
gaze evoked nystagmus. On neurological examination, there protein10.
was weakness in sensory and motor component of trigeminal
nerve. Left sensorineural hearing loss was present. Uvula INTRODUCTION
ϐ Ǥ
of speech was observed. Rest Cranial Nerve examination was Neurotrophic keratitis is a rare degenerative corneal
normal. There was imbalance on tandem walking suggestive of disease caused by an impairment of trigeminal corneal
cerebellar signs. innervation, leading to a decrease or absence of corneal
www. dos-times.org 19
CORNEA (2)
(1) (4)
Figure 1&2: At Presentation
(3)
Figure 3&4: After Punctal Plugs
sensation. Many ocular and systemic anaesthesia13,14. The corneal epithelium performed by touching the central
diseases can determine a lesion at ϐ and the peripheral cornea with the tip
ϐ
ǣ dystrophic changes and defects with of a cotton swab16. Alternatively, the
the nucleus in the pons, the Gasserian poor tendency to spontaneous healing. Cochet–Bonnet aesthesiometer may be
ganglion, the trigeminal ophthalmic In addition to loss of protective sensory used to localize and quantify the loss
branch, the nasociliary nerve, or the stimulus, decreased innervation results of corneal sensitivity, recording the
long ciliary nerve. The most common in intracellular edema, exfoliation, loss of patient’s response at the touch of a nylon
causes of corneal anaesthesia are viral goblet cells and epithelial breakdown with line (between 0 and 6 cm)17. Generally,
infection (herpes simplex and herpes persistent ulceration. The progression of the severity of neurotrophic keratitis
zoster keratoconjunctivitis) followed by the disease may lead to corneal ulcers, is related to the severity of the corneal
chemical burns, physical injuries, and melting, and perforation15. While the sensory impairment.
corneal surgery11. Intracranial space- clinical diagnosis is easily oriented from
occupying lesions such as neuroma,
ϐǡ Blink rate is markedly decreased if
meningioma, and aneurysms may management of this condition is one of bilateral neurotrophic keratitis occurs.
also determine a compression of the ϐ
However, the disease is frequently
trigeminal nerve or ganglion and produce all corneal diseases. unilateral and blinks can be normal
an impairment of corneal sensitivity12. because the other unaffected eye elicits
Systemic diseases such as diabetes, DIAGNOSIS normal symmetrical blink.
multiple sclerosis, and leprosy may
decrease sensory nerve function or Accurate ocular examination is A Schirmer test should be carried
ϐ
necessary in neurotrophic keratitis.
ϐ
Corneal sensitivity test may be be affected by the reduction of corneal
sensitivity18,19.
Dept of Cornea and Refractive Surgery Shri Ganapati Netralaya, Jalna
Dr. Namrata Kabra MS Dr. Namrata Majhi MS
20 DOS TIMES - NOVEMBER-DECEMBER 2016
CORNEA
(5) (6)
Figure 5&6: At 3 Months Followup
(7) (9) avoid the development of corneal ulcer, to
promote healing of the epithelial defect,
(8) that the more severe the corneal sensory and to prevent the recurrence of the
impairment, the higher the probability of epithelial breakdown. Corneal or scleral
Figure 7-9: At presentation disease progression20. therapeutic contact lenses have been
ϐ
ǡ proposed, but their use may increase
TREATMENT the risk of secondary infections and may
bengal, or lissamine green shows corneal Neurotrophic keratitis represents cause sterile hypopyon22,23,24. In case of
and conjunctival epithelial changes. corneal ulcers that are unresponsive to
ϐ
ϐ
Accurate examination of the ocular diseases still lacking treatment. lenses, tarsorraphy can be considered.
eyelids’ margin, position, and motility is The goals of treatment are to prevent Alternatively, it is possible to cover the
important because exposure keratitis and progression of corneal damage and to epithelial defect by means of amniotic
blepharitis can also be associated with promote epithelial healing. The therapy membrane graft25 or to utilize a palpebral
neurotrophic keratitis. must be prompt and based on the clinical spring or botulinum A toxin injection
stage of the disease21. of the eyelid elevator26,27. Steroids, by
In all corneal ulcers, a microbiological inhibiting stromal healing, may increase
examination should be performed to The presence of punctate keratopathy the risk of corneal stromal melting and
exclude bacterial, fungi, or viral infections. (stage 1) requires administration of perforation, thus their use should be
PROGNOSIS
Ǧ ϐ
Ǥ considered with caution.
The therapy at this stage aims to improve
The prognosis of neurotrophic epithelial quality and transparency, and When a corneal ulcer develops (stage
keratitis depends on several factors to avoid epithelial breakdown. 3), the therapy is aimed at promoting
such as the cause of the impairment of corneal healing, and preventing corneal
corneal sensitivity, the degree of corneal When an epithelial defect develops melting and perforation. Tarsorraphy is
hypoaesthesia, and the association with (stage 2), the aims of treatment are to effective. Small perforations can be treated
other ocular surface diseases such as dry with the application of cyanoacrylate
eye, exposure keratitis, and limbal stem glue followed by a soft bandage contact
ϐ
Ǥ
lens28,29,30. Larger defects require lamellar
or penetrating keratoplasty29.
NEWER MODALITIES AND FUTURE
DEVELOPMENTS
In an open uncontrolled study,
topical nerve growth factor NGF
treatment induced corneal healing in
43 patients affected by moderate and
severe neurotrophic keratitis (stages 2
and 3)31,32. Nerve growth factor (NGF) is
currently not available for clinical use. It is
one of the body’s peptides and belongs to
the family of neurotrophins. It functions
as a chemokine on the growing axon of
peripheral nerves. Positive effects have
also been reported on its impact in the
CNS. After initial damage to a peripheral
www. dos-times.org 21
CORNEA
nerve, NGF is produced locally by the REFERENCES In: Norn MS (ed). External Eye Diseases.
affected nerve. It induces the increased Methods of Examination. Munksgaard
expression of a NGF receptor trk-a i. Mackie IA: Neuroparalytic (neurotrophic) International Publisher Ltd: Copenhagen,
(tyrosin receptor kinase A,33). Parallel the keratitis. Symposium on contact lenses: 1974.
brain derived neurotrophic factor (BDNF) transactions of the New Orleans Academy of ͳͺǤ
ǡ ϐ Ǥ
is increasingly expressed and binds to ǡ ǣ Ǣ ͳͻ͵Ǥ production in patients with neurotrophic
its receptor trk-b. The interplay of both Ǥ ͳͻͻǢ ͳͷǣ ͳ͵ͷȂ͵ͺǤ
factors and receptors communicate ii. Mackie IA: Role of the corneal nerves in 19. Wright P, Mackie IA. Mucus in the healthy
neural reconstruction and its related pain destructive disease of the cornea. Trans and diseased eye. Trans Ophthalmol Soc UK
sensations34.
ͳͻͺǢ ͻ͵ǣ͵͵Ǥ ͳͻǢ ͻǣ ͳȂǤ
20. Cobo LM. Corneal complications of herpes
When performing surgery, sensory 1. Daras M, Koppel BS, Heise CW, Mazzeo zoster ophthalmicus. Prevention and
nerves ought to be protected if somehow MJ, Poon TP, Duffy KR: Multiple spinal Ǥ ͳͻͺͺǢ ǣͷͲȂͷǤ
possible. In cases where nerves have intradural schwannomas in the absence of 21. Lambiase A, Rama P, Aloe L, Bonini S.
ϐ
von Recklinghausen’s disease. Spine (Phila Management of neurotrophic keratopathy.
or iatrogenic damage, an immediate Pa 1976)1993,18:2556-2559. ͳͻͻͻǢ ͳͲǣ ʹͲȂǤ
or soonest possible reconstruction is 22. Gould HL. Treatment of neurotrophic
desirable. So far the best reconstruction 2. Reese AB: Tumors of the Eye. 2nd edition. keratitis with scleral contact lenses. Eye Ear
technique seems to be a tension free ǣ
Ǣ ͳͻ͵ǣͳͻͲǦʹͲʹǤ ͳͻǢ Ͷǣ ͳͶͲȂͳͶǤ
end-to-end anastomosis. In cases where 534-535 23. Kent HD, Cohen EJ, Laibson PR, Arentsen JJ.
a rerouting is not possible, a sural or Microbial keratitis and corneal ulceration
great auricular nerve interposition graft ͵Ǥ ϐ ǡ ǡ ǡ associated with therapeutic soft contact
is mandatory. P, Cantore G: Primary benign tumors of the Ǥ
ͳͻͻͲǢ ͳǣͶͻȂͷʹǤ
orbital cavity: comparative data in a series ʹͶǤ ϐ Ǥ
Eppley and Snyder35 concluded of patients with optic nerve glioma, sheath corneal epithelial healing. Acta Ophthalmol
after their microanatomic analysis, that meningioma, or neurinoma. Surg Neurol ͳͻͻʹǢ ʹͲʹǣ ͵Ȃͺ͵Ǥ
of all possible graft sources, the great 1996,45:147-153. 25. Lambiase A, Rama P, Aloe L, Bonini S.
auricular nerve is most similar to the Management of neurotrophic keratopathy.
trigeminal nerve and therefore the ideal 4. Capps DH, Brodsky MC, Rice CD, Mrak RE, ͳͻͻͻǢ ͳͲǣ ʹͲȂǤ
interposition material. The sural nerve is Glasier CM, Brown HH: Orbital intramuscular 26. Kirkness CM, Adams GGW, Dilly PN, Lee JP.
used when bridging greater distances of schwannoma. Am J Ophthalmol Botulinum toxin A-induced protective ptosis
up to 20-30cm. The nerve can be dissected 1990,110:535-539.
Ǥ ͳͻͺͺǢ ͻͷǣ
free through one long calf incision or by 473–80.
utilizing multiple small incisions (rope 5. Nagashima H, Yamamoto K, Kawamura A, 27. Mc Neill JI, Oh YH. An improved palpebral
ladder technique36). A resulting sensoric Nagashima T, Nomura K, Yoshida M: Pediatric spring for the management of paralytic
defect on the calf is inevitable. The nerve orbital schwannoma originating from the Ǥ ͳͻͻͳǢ ͻͺǣ
consists of up to 11-12 fascicles and has a oculomotor nerve. J Neurosurg Pediatr 715–19.
median diameter of 2.1mm. 2012,9:165-168. 28. Fogle JA, Kenyon KR, Foster CS. Tissue
adhesive arrests stromal melting in the
CONCLUSION 6. Butt ZA, McNab AA: Orbital neurilemmoma:
Ǥ
ͳͻͺͲǢ ͺͻǣ
report of seven cases. J Clin Neurosci 795–802.
The management of neurotrophic 1998,5:390-393. 29. Hirst LW, Smiddy WE, Stark WJ. Corneal
keratitis represents a real therapeutic perforations: changing methods of
dilemma for ophthalmologists. Several 7. Rootman J, Goldberg C, Robertson W: Primary ǡ ͳͻͲȂͳͻͺͲǤ ͳͻͺʹǢ
medical and surgical treatments have orbital schwannomas. Br J Ophthalmol 89: 630–34.
been proposed to halt the progression 1982,66:194-204. 30. Webster RG, Slansky HH, Refojo MF, Boruchoff
of the disease and to avoid corneal SA, Dohlman CH. The use of adhesive for
perforation. These surgical procedures 8. Rose G, Wright JE: Isolated peripheral nerve the closure of corneal perforation. Arch
can preserve ocular integrity but they sheath tumours of the orbit. Eye 1991, 5:668- ͳͻͺǢ ͺͲǣ ͲͷȂͲͻǤ
ϐ
673. 31. Bonini S, Lambiase A, Rama P, Caprioglio
visual function. Neuropeptides, growth G, Aloe L. Topical treatment with nerve
factors and nerve interposition graft 9. Hanemann CO, Evans DG: News on the growth factor for neurotrophic keratitis.
may represent a future therapeutic genetics, epidemiology, medical care and ʹͲͲͲǢ ͳͲǡ ͳ͵ͶȂͳ͵ͷͳǡ
approach for the cure and prevention of translational research of Schwannomas. J discussion 1351–52.
neurotrophic keratitis. Neurol 2006,253:1533-41. 32. Lambiase A, Rama P, Bonini S, Caprioglio G,
Aloe L. Topical treatment with nerve growth
10. Scheithauer BWJ, Erlandson R: Schwannoma. factor for corneal neurotrophic ulcers. N Engl
Atlas of Tumor Pathology: Tumors of the
ͳͻͻͺǢ ͵͵ͺǣ ͳͳͶȂͺͲǤ
Peripheral Nervous System 3rd edition. 33. Sullins JS, Carnes DL, Kaldestad RN,
1999, 105-176. Wheeler F. Time Course of the Increase in
trk A Expression in Trigeminal Neurons
11. Groos Jr EB. Neurotrophic keratitis. In: After Tooth Injury. Journal of Endotontics.
Krachmer JH, Mannis MJ, Holland EJ (eds.) ʹͲͲͲǢʹǣͺͺȂͻͳǤ
Cornea: Clinical Diagnosis and Management. 34. Behnia A, Zhang L, Makepeace C, Gold MS.
Mosby: St Louis, 1997, pp 1340. Changes in Trk B-like Immunoreactivity in
Rat Trigeminal Ganglion After Tooth Injury.
12. Puca A, Meglio M, Vari R, Tamburrini
Ǥ ʹͲͲ͵Ǣʹͻǣͳ͵ͷȂͳͶͲǤ
ǡ
Ǥ ϐ 35. . Eppley BL, Snyders RV. Microanatomic
dysfunction in 136 patients with middle and Analysis of the Trigeminal Nerve and
Ǥ ͳͻͻͷǢ Potential Nerve Graft Donor Sites. J Oral
35: 33–37.
Ǥ ͳͻͻͳǢͶͻǣͳʹȂͳͺǤ
36. Hausamen JE. Principles and Clinical
13. Hyndiuk RA, Kazarian EL, Schultz RO, Application of Microberve Surgery and Nerve
Seideman S. Neurotrophic corneal ulcers in Transplantation in the Maxillofacial Area.
Ǥ
ͳͻǢ
95:2193–96. Ǥ ͳͻͺͳǢǣͶʹͺȂ͵͵Ǥ
14. Kara-corlu MA, Cakiner T, Saylan T.
Neurotrophic corneal ulcers in diabetes
Ǥ
ͳͻǢ ͻͷǣ ʹͳͻ͵Ȃ
96.
15. Mackie IA. Neuroparalytic keratitis. In:
Fraunfelder F, Roy FH, Meyer SM (eds).
Current Ocular Therapy. WB Saunders:
Philadelphia, PA, 1995, 452–54.
16. Faulkner WJ, Varley GA. Corneal diagnostic
tecnique. In: Krachmer JH, Mannis MJ,
Holland EJ (eds).Cornea: Foundamentals
of Cornea and External Disease. Mosby: St
Louis, MO, 1997, 275–281.
17. Norn MS. Measurement of sensitivity.
Financial Interest: ϔ
Ȁ
Ǥ
22 DOS TIMES - NOVEMBER-DECEMBER 2016
REFRACTIVE SURGERY
UNFOLDING THE CONCEPT OF INTRACORNEAL RING SEGMENT
IMPLANTATION (ICRS)
Reena Singh, Srujana D, Rajesh Sinha
Introduction and evolution of intracorneal ring segment: holes for manipulation, the ring segments available as a pair
Intracorneal ring segments (ICRS) implantation is a new ͳͷͲι
Ǥ ϐ
modality of treatment for disorders of corneal ectasia procedure and also they can be implanted away from the radial
which include Keratoconus, Keratoglobus, pellucid incision site, thereby minimizing potential incision-related
marginal degeneration (PMD) and post LASIK ectasia. complications.In Europe, Intacs inserts are available with
In 1949 Barraque experimented with implantation of thicknesses ranging from 0.25 to 0.45 mm.
various materials in the cornea of cat and rabbit eyes to induce
refractive changes1. The idea of implanting a corneal ring KeraRing
to change the refractive power of the cornea was introduced ǡ ϐ ǡ
by Blevatskaya in 19662. In 1978, Fleming and Reynolds of asymmetric segments, are triangular in cross section and
conceived the idea of a ring-shaped implant (intrastromal smaller in diameter than Intacs. Hence more effective than
corneal ring [ICR]) that could be introduced through a single Intacs but associated with increased chance of night glare. It
radial incision3Ǥ ͳͻͻͳǡ ϐ is available in two models for
human clinical trials began in Intracorneal ring segments (ICRS) 5-mm implantation in optical
Brazil with 360° ICR in corneas zones of 5 mm, 5.5 mm, and
of nonfunctional human eyes. implantation is a new modality of 6 mm. There are 40 different
Colin and coworkers performed treatment for disorders of corneal variations of thickness, arc
ϐ
ectasia which include Keratoconus, length and diameter, allowing
implantation for keratoconus in for enhanced customization
June 1997. In 1999, the trade Keratoglobus, pellucid marginal of corneal remodeling and
name Intacs inserts was adopted
for commercial sale of the ICRS, degeneration (PMD) and post LASIK refractive correction.
and FDA approval was granted
for the commercial sale of Intacs ectasia. In 1949 Barraque experimented Ferrara Ring ǡ ϐ
inserts for myopia of -1.00 to with implantation of various materials
-3.00 D with astigmatism of less
than 1.00 D. In 2004, INTACS in the cornea of cat and rabbit eyes to developed in 1986 in Brazil, is
inserts (sizes 0.25 -0.35mm) made of yellow PMMA, an inert
were given FDA Humanitarian induce refractive changes and biocompatible acrylic. It is
Device Exemption for their use in
was extended to 0.4 and 0.45 mm available in apical diameters of
keratoconus and exemption ͷ ǡ ϐ
ͻͲ
rings in 2010. The insertion mm to 210 mm and a variable thickness of 0.15 mm to 0.30 mm.
method has evolved from manual 360-degree ring insertion Myoring
with radial to circumferential incision for tunnel creation to
segmental implantation with only radial incision. The laser Myoring is a foldable ring, used for cases of high myopia
assisted tunnel creation has further increased safety and and astigmatism, is available in diameters of 5 to 8 mm and
predictability of the ring insertion. thickness of 150 to 300 microns. Its insertion is recommended
at a depth of 300μ. It has very few clinical studies worldwide.
Intracorneal ring segments (ICRS) can be grouped into 2
categories based on diameter, cross-sectional shape, thickness
and arc length: INDICATIONS
1. Intracorneal ring segments (ICRS) of up to 355 degree arc 1. FDA has approved use of Intacs for myopia -1.00 to -3.00 D
length such as Ferrara ring, Intacs and Keraring. Currently with astigmatism of +1.00 D or less.
these are the most commonly available intrastromal 2. Patients aged 21 years or older
corneal ring segments. 3. Patients with documented stability of refraction as
2. Continuous complete intracorneal ring such as MyoRing. demonstrated by a change of less than or equal to 0.50 D
for at least 12 months
Intacs 4. Ectatic corneal disorders
It is an open-ended PMMA transparent ring with an outer a. Mild to moderate keratoconus (stage 1 and 2 Amsler–
diameter (R2) of 8.1 mm and an inner diameter (R1) of 6.8 mm Krumeich) with
(Figure 1). It is hexagonal in cross section and has positioning
Ȉ
ǡ
www. dos-times.org 23
REFRACTIVE SURGERY
Figure 1(a): Intacs in-situ. Figure (b): ASOCT of ends of rings; in a case of moderate Keratoconus
Ȉ eye rubbing Ǥ ȋϐ
Ȍ
8. Presence of active infection limbus separates the load on the cornea
readings of less than 53 D 9. Localized or systemic autoimmune resulting from the intraocular pressure
into an independent load inside the
Ȉ
ϐ
inner diameter of the implant and an
10. Patients on with chances of changing independent load between the outer
thickness 400 microns at diameter of the implant and the limbus
refractions like on steroids therapy (corneal diameter). However such a
the site of implantation and pregnancy strengthening effect is not seen with ICRS
11. Recurrent corneal erosion syndrome and incomplete rings5.
Ȉ
12. Corneal dystrophy and patients
on Amiodarone, Sumatriptan, Pearls for new beginners
b. Pellucid marginal degeneration Isotretinoin therapy
13. Cataract Patients should be counselled
c. Irregular astigmatism after properly about the procedure and the
Optical principle and effect on expected outcomes. A good refraction
radial keratotomy with correct axis of cylinder is utmost
corneal geometry prerequisite. Peña-García et al in their
d. Post-LASIK ectasia with study concluded that the best outcomes
The main mode of action of ICRS for implanting ICRS were observed in
Ȉ ʹ is ‘arc-shortening’ effect2,4 caused by those cases where the refractive and
increased lamellar volume of the implant topographic cylinder did not differ by
BCVA which increases stress on central more than 15° of separation6. Using
ϐ
keratometry and corneal topography
Ȉ
Ͷ
ϐ on central cornea. The corneal ring (orbscan and pentacam) the site, size and
complies with Barraquer and Blavatskaya thickness of rings are calculated which
as severe visual limitation postulates: thicker the ring greater is should be matching with the refraction,
the correction achieved, for each 50 μ calculated astigmatism and the axis.
with a BCVA worse than increase in thickness there is additional Endothelial perforation can occur in
ͲǤ
ϐǤ both manual and laser assisted tunnel
20/40 ȋ Ȍ ϐ creation ,hence it is very important to see
effect. Presence of a corneal inlay also the corneal thickness at and around the
CONTRAINDICATIONS provides biomechanical support for the tunnel which needs to be created for the
ocular tissue. In addition, it maintains the inserts at 5 or 6 mm area using pentacam/
ICRS should not be implanted in positive asphericity of the cornea. orbscan/ ASCOT / USG pachymetry/
multiple methods. One needs to choose
keratoconus patients who can achieve When there is no discontinuity the thinnest pachymetry at the site of
along the circumference of the implant
functional vision with contact lens, are such as the MyoRing, the implant acts
ȋϐ
Ȍ
younger than 21 years of age, do not have inside the cornea using the enormous
clear central corneas, and have a corneal
ͶͷͲ Ɋ
incision site. Further, ICRS is contra-
indicated in the following situations:
1. Patients with unrealistic expectation
2. Diabetes (advanced and
uncontrolled)
3. Advanced keratoconus (stage 3 and
4 Amsler–Krumeich)
ͶǤ
εͲ
5. Keratoconus with corneal opacities
or Hydrops
6. Patients with grade 1-3 post-LASIK
ectasia
7. Severe atopic disease with chronic
Dr. Rajendra Prasad Centre for Ophthalmic Sciences,AIIMS, New Delhi
Dr. Reena Singh MD Dr. Srujana D. MS Prof. Rajesh Sinha MD
24 DOS TIMES - NOVEMBER-DECEMBER 2016
REFRACTIVE SURGERY
Table 1: The Normogram suggesting Table 2: The Normogram suggesting ring thickness for Intacs recommendation
ring distribution based on area for keratoconus (colin jcrs 2006), based on corneal asymmetry and manifest
of corneal ectasia and manifest refraction(SE)
refraction (SE)
Types of cornea Preoperative ref error se <3 ε͵
Asymmetric 0.25mm/0.30mm 0.25mm/0.30mm
Moderately asymmetric 0.35mm/0.40mm 0.40mm/0.45mm
High asymmetric 0.25mm/0.40mm 0.25mm/0.45mm
Global 0.40mm/0.40mm 0.45mm/0.45mm
Central 0.40mm/0.40mm 0.45mm/0.45mm
Table 3: The Normogram suggesting the number, size and site of ring insertion
based on types of cones for keratoconus (Colin JCRS 2006)
Type of keratoconus
ϐ
Asymmetrical cone 2 Intacs inserts of different thicknesses
(1 thinner Intacs insert placed superiorly, 1 thicker
implantation and calculate 80% depth of Intacs insert placed inferiorly)
it then look for residual thickness. There
is no clear consensus on safe residual bed Global cone 2 Intacs inserts of the same thickness (1 Insert each
Ǣ ǡ ͳͷͲ ͳͲ placed superiorly and inferiorly)
μ thicknesses should be left below the
ring. Pupil diameter is another important Central cone 2 Intacs inserts of the same thickness (1 Insert each
parameter, which needs to be noted in placed superiorly and inferiorly)
preoperative workup. Depending on the
mesopic pupil diameter patient may be implantation of ring segments can be keratometric outcomes between two
counseled about the expected glare. Pupil created by two methods: manual and procedures but fewer complications and
diameter of more than 7 mm is a relative with femtosecond laser. The reference less postoperative discomfort for patients
contraindication for implantation. point is marked at the pupillary centre has made femtosecond the preferred
or geometric centre. In the manual option for surgeons11.
In case of both laser assisted and method, a 1mm radial incision is given
manual method of tunnel creation, center on the steepest axis at 70-80% of corneal Combination Therapies
is marked manually either at purkinje’s thickness with a calibrated diamond knife
ϐ
with the help of intra-operative ultrasonic Intacs implantation has been
limbal centre, in the supine position. pachymetry. Corneal pockets are created combined with various other treatment
In laser-assisted implantation, tunnel using pocketing hooks on each side of the modalities for keratoconus. Combination
markings are done before applanation as radial incision. A semi-automated suction with CXL has shown synergistic effects
it could induce possible rotation. In case of ring is placed around the limbus and and triple therapy with CXL and PRK
manual insertion, axis needs to be marked suction increased to 630 mbar. Then two has been shown to be well tolerated
before the patient lies down as supine semicircular dissectors are advanced into and effective. A randomized study
position induces cyclotorsion. However the lamellar pockets by rotating clockwise demonstrated that ICRS placement
in laser assisted method, calculations are and counterclockwise to create two followed by CXL led to a statistically
based on the pentacam parameters given semicircular tunnels. The suction device ϐ
ǡ
to the manufacturer. Planning of incisions is removed and the ring segments are manifest cylinder, and keratometry 6
and calculation of depth is done before inserted into the channels. The channels months after treatment than patients who
hand and entered in the machine which can also be prepared with a femtosecond had the treatments in the reverse order ie
automatically cuts the desired sites of laser (Intralase, Irvine, CA, USA). The CXL followed by ICRS12. Intacs following
incisions taking nasal or temporal side infrared Nd:Glass laser (wavelength PKP for keratoconus has been shown to
of eyes as 0 or 180 degree and corneal 1053nm) can create channels at desired decrease astigmatism and improve BCVA.
vortex as the center. (Figure 2) Despite depth with a high degree of precision. Toric ICL following implantation of Intacs
the blade less laser tunnel creation Intacs Combined CXL can be performed either and CXL has also shown good results.
ϐ before insertion of ring segments when
curve. Table 1,2 and 3 show normograms the corneal channels have been created COMPLICATIONS
of the distribution and thickness of the or after the ring segments have been
ring segments according to the location inserted. Femtosecond laser technique Complications associated with
and area of ectasia, spherical equivalent offers increased precision, reproducibility, implantation of ring segments are few
(SE), corneal asymmetry and type of and speed of tunnel creation9. However, and mainly include epithelial defects
keratoconus cone7,8. Kouassi etal have concluded in their at the keratotomy site, extension of the
study that the depth predictability of incision towards the central visual axis or
Methods of insertion ϐ
towards the limbus, persistent gaping of
different10. Many studies have shown incision, segment migration into anterior
The channels required for no difference in visual, refractive and
ϐ
ǡ
ǡ
ϐ
www. dos-times.org 25
REFRACTIVE SURGERY
Figure 2: A case of keratoconus, intolerant to RGP lenses, UCVA OS 4/60 and BCVA 6/12 with -3.0ds/-10.0 dc@ 700. The planning of ring implantation
UJQYP KP ſIWTG DGNQY CPF UKVG QH KPEKUKQP RNCPPGF CV UVGGRGT CZKU CPF OCTMKPI UJQYKPI VJG RNCEGOGPV QH TKPIU CTQWPF VJG UVGGRGT CZKU HQT ƀCVVGPKPI
VJG UVGGRGT CZKU
the superior edge of inferior segment, ϐ
Ǥ Advantages of Intacs
intrastromal keratitis and glare. Post perforation is large then wound has to
INTACS keratitis is a rare but devastating be sutured and implantation should be As compared to keratoplasty Intacs is
complication which could present as focal postponed. If the ring after implantation a minimally invasive procedure, its effect
ϐ
is seen to be migrating into anterior
ϐ ǡ
with pain and most commonly caused chamber due to perforation, then the is reversible and has long term stability
by Staphylococcus aureus. The other ring should be explanted, the wound with early visual rehabilitation. Also
less causative organisms are staph sutured and let the cornea heal for any Intacs placement does not involve central
epidermidis, clostridium perfringens, future intervention. If minor endothelial cornea and in addition can be combined
acanthamoeba and fungal isolates. Loose perforation has been missed or with other modalities of treatment like
suture, gaping of wound, early removal of diagnosed after surgery in the follow-up, contact lens and CXL for additional
suture, steroids, BCL, diabetes and trauma one needs to observe for complications: ϐǤ
are the risk factors associated with post migration into A/C or infection, if they can not be used in advanced disease.
INTACS keratitis. Management includes occur then ring has to be explanted. In
ϐ ǡ
ǡ case of incorrect entry into channel, use CONCLUSION
explantation/ removal of inserts when separator at the entry point and re-enter.
necessary and in severe cases corneal To prevent incorrect entry into channel ICRS can improve functional
transplantation. one needs to start implantation of the vision in corneal ectasia especially in
insert immediately after creation as the mild to moderate kearatoconus cases.
Intra-operative problems bubble at the site gives guide for the Contact lens tolerance improves in
actual location of channel13. the majority of keratoconus patients.
encountered during femto-assisted The newer modality of tunnel creation
Progression of ectasia/ keratoconus with femtosecond laser has improved
tunnel creation and suggested predictability and decreased tunnel
Recent long-term (5 year) follow- related complications. Long-term results
solutions up reports suggested that implantation Ǣ ǡ
of Intacs leads to arrest of progression combination therapies and effect on
In case of incomplete tunnel creation, in 90% of patients with recorded pre- disease progression need further
mechanical manipulation could be done op progression. These results are evaluation.
with the ring segment and implantation comparable to CXL which also show halt
done in the same tunnel. Also opposite in progression of keratoconus in 85- REFERENCES
direction of the tunnel could be used 95% of patients14. A comparative study
to enter the tunnel, which could be between single inferior Intacs alone vs 1. Barraquer JI: Queratoplasia
completed using mechanical dissector or combination of Intacs and CXL showed refractiva, estudios e informaciones.
separator. If applanation failure occurs ϐ
Oftalmologicas 2:10–30, 194.
then manually channels are created, if keratoconus and reduction in manifest
it occurs just at the beginning then one cylinder with combination than with 2. Blevatskaya ED. Intralamellar
needs to redo the applanation. In case Intacs alone15. homoplasty for the purpose of
ǡ
ϐ relaxation of refraction of the eye.
before implanting the ring then channels Arch Soc Am Ophthalmol Optom.
will have to be recreated with 30μm ͳͻͺǢǣ͵ͳͳȂʹͷǤ
26 DOS TIMES - NOVEMBER-DECEMBER 2016
REFRACTIVE SURGERY
3. Fleming JF, Reynolds AE et al: The
ʹͲͲǢ ͵ʹǣͶȂͷͷǤ intrastromal corneal rings and corneal
ͻǤ ǡ º
ǡ Ǥ
intrastromal corneal ring: two cases in collagen crosslinking for keratoconus.
Intacs insertion with the femtosecond
Ǥ
ͳͻͺǢ͵ǣʹʹȂʹ͵ʹǤ laser for the management of
ʹͲͲͻǢ͵ͷǣʹͲͺͶȂ
keratoconus: one-year results. J
4. Fleming JF, Wan WL et al: The theory
Ǥ ʹͲͲǢ͵ʹǣʹͲ͵ͻǦ 91.
42.
of corneal curvature change with the 10. Kouassi FX, Buestel C, Raman B, 13. Efekan Coskunseven, George D.
Melinte D, Touboul D, Gallois A,
intrastromal corneal ring. CLAO J Colin J.Comparison of the depth Kymionis, Nikolaos S. Tsiklis, Serife
predictability of intra corneal ring
ͳͻͺͻǢͷǣͳͻȂͳͻ͵Ǥ segment implantation by mechanical Atun, Ebru Arslan, Charalambos
versus femtosecond laser-assisted
5. Albert Daxer. Biomechanics of Corneal techniques using optical coherence S. Siganos, Mirco Jankov, Ioannis
tomography (OCT Visante) .J Fr
Ǥ Ǥ ʹͲͳͷǢ͵ͶǣͳͶͻ͵Ȃ Ǥ ʹͲͳʹǢ͵ͷǣͻͶǦͻǤ G. Pallikaris. Complications of
11. Rabinowitz YS, Li X, Ignacio TS,
149825. Maguen E. Intacs Inserts using the intrastromal corneal ring segment
femtosecond laser compared to the
6. Peña-García P, Alió JL, Vega-Estrada A, mechanical spreader in the treatment implantation using a femtosecond
of keratoconus. J Refract Surg.
Barraquer RI. Internal, corneal, and ʹͲͲǢʹʹǣͶǦͳǤ laser for channel creation: a survey
12. Efekan Coskunseven Mirko R. Jankov II,
refractive astigmatism as prognostic Farhad Hafezi, Serife Atun.et al.. Effect of 850 eyes with keratoconus. Acta
of treatment sequence in combined
factors for intrastromal corneal ring Ophthalmol. 2011:89:54–57.
segment implantation in mild to 14. Bedi R, Touboul D, Pinsard L, Colin J.
moderate keratoconus. J Cataract Refractive and topographic stability
Ǥ ʹͲͳͶǢͶͲǣͳ͵͵ȂͶͶǤ of Intacs in eyes with progressive
7. Shabayek MH, Alió JL.
ǣ ϐ ǦǤ
Intrastromal corneal ring segment
Ǥ ʹͲͳʹǢʹͺǣ͵ͻʹȂͻǤ
implantation by femtosecond 15. Chan CC1, Sharma M, Wachler BS.
laser for keratoconus correction. Effect of inferior-segment Intacs with
ǤʹͲͲǢͳͳͶǣͳͶ͵ǦͷʹǤ and without C3-R on keratoconus.J
8. Joseph Colin, .European clinical
Ǥ ʹͲͲǢ͵͵ǣͷǦͺͲǤ
evaluation: Use of Intacs for the
treatment of keratoconus .J Cataract
Financial Interest: ϔ
Ȁ
Ǥ
www. dos-times.org 27
CATARACT
IOL POWER CALCULATIONS (PART-3):
SPECIAL SITUATIONS
T Saurabh Sawhney, Ashima Aggarwal
here are four special situations we will be
considering.
1. Measurement jinxes.
2. The paediatric eye.
3. The post-refractive surgery eye.
4. Toric IOL power calculations.
MEASUREMENT JINXES
Ǣ
most importantly, on keratometry and axial length. If these
measurements cannot be recorded precisely there will be
corresponding errors in prediction. If there is an actual
measurement error, optimization cannot compensate for it. The
surgeon should therefore try to get measurements as accurately
as possible. Figure 1: Location of the fovea on the sloping wall of the posterior
UVCRJ[NQOC ECP ECWUG GTTQPGQWU CZKCN NGPIVJ TGEQTFKPI
CORNEAL PATHOLOGY greater compression error than usual. If a contact A-scan is the
only option, ensure that the patient is looking directly at the
Abnormal corneas including but not limited to scars, ϐ Ǥ
pterygium, and dry eye, are going to produce inaccurate
keratometry values. If the mires are too distorted, a manual
keratometer may yield more accurate values than automated Silicone Oil filled eye
systems. If there is no way to get a corneal reading, the other
eye’s keratometry should be used. The core issue here is the velocity of sound through
silicone oil. In silicone oil of viscosity 1000 centistokes, the
AXIAL LENGTH velocity of sound is 987 m/s, compared to 1532 m/s through
vitreous. This means that it takes longer for the ultrasound
ϐ
wave to travel through silicone oil, which is interpreted by
the following situations the machine as a longer axial length. Another issue is the
absorption of sound waves as they pass through the oil, which
1. Posterior staphyloma. decreases the sensitivity, at times making it impossible to get a
ʹǤ
ϐ Ǥ Ǥ ǡ
ϐ
3. Pseudophakic eye. erroneous.
4. Hyperopic eye.
Posterior staphyloma ϐ
ͳ͵ͲͲ
The presence of a posterior velocity, a correction factor of 0.71 has been determined1. To
staphyloma in myopic eyes
This article is the last of a three part obtain the true axial length,
poses a challenge because of the simply multiply the measured
localization of the fovea. Since
the fovea may lie anywhere on series on IOL power calculations. The axial length with this correction
focus is on special situations in IOL factor. However, this factor
the slope of the staphyloma, needs to be changed as per the
the measured length of the eye power calculation
viscosity of the oil. An additional
may be quite different from the problem arises if the eye is only
optical path length (Figure 1). The best method of ensuring that ϐ ǡ
the optical path length is measured is to use optical biometry, the proportion of the optical path length occupied by the oil
which has a very narrow beam width and measures directly to
ϐǤ
the fovea. If this is unavailable, or cannot be performed because The repeatability of measurements is much better with
ϐ
ǡ optical biometry2. Using light instead of ultrasound reduces the
used. To better ensure that the correct point on the posterior
ǡ ϐ
Ǥ
pole is measured, a B-scan may be combined. Contact A-scan This is because the difference in refractive indices of vitreous
is the least reliable method. A second drawback of using the and silicone oil is much lesser than the difference in the velocity
contact method is lowered ocular rigidity, which may create of ultrasound through them. The values obtained by using
optical biometry in the ‘silicone-oil’ mode are automatically
www. dos-times.org 29
CATARACT
adjusted to compensate for hyperopic eyes should be done
this source of error and may be separately. Any third generation
used directly for calculating IOL or later theoretical formula
power. ϐ
An additional caveat is IOL power prediction, although
that the IOL will make its own the Hoffer-Q formula has been
interface with the silicone oil. widely recommended.
Since the refractive index of
the oil is different from that of THE PAEDIATRIC EYE
vitreous, the effective power Measurement issues
ϐ
ϐ ϐ
affected. However, this will measurement. The problem is
only happen if the interface is that of continuous movement,
curved. To avoid this problem, it which leaves little time to
is recommended that only IOLs measure any parameter. The
with a plano posterior surface options are two-fold.
be implanted in these cases. Figure 2: +1.U RTQFWEG OWNVKRNG HWNN TGƀGEVKXKV[ URKMGU OCMKPI KV 1. Use a fast recording
Pseudophakic Eye FKHſEWNV VQ CUUGUU VJG CZKCN NGPIVJ device, and take multiple
readings, averaging them out.
The reason for measuring the axial measured axial length is ϐ
length in the presence of an IOL is to ALCORRECTED = ALPHAKIC + C x T child to position on a manual or an
address an unexpected postoperative Using optical biometry may once autokeratometer. Use a hand held
refractive surprise. If an IOL exchange again prove to be the best bet in this keratometer. Despite concerns about
is being considered, then it makes sense situation. A small, 25 eye study by Pitault relative lack of accuracy and poor
to get it exactly right the second time ϐ
judgement of astigmatic axis, it can
around. the axial length measurements before and still provide usable information.
ϐ after implanting a phakic IOL when using For axial length measurement, the
to choose the correct setting on the the IOL Master4. The fact that patients ϐ Ǧ
machine. A measurement performed in who have received phakic IOLs usually are obvious, so optical biometry is
the phakic or cataract mode will produce have highly myopic eyes, with a greater the default strategy. However, it may
erroneous results. Even the IOL material likelihood of posterior staphyloma, also not be possible in many cases due to
ϐ
ϐ
Ǥ favours the use of optical biometry. lack of cooperation by the child.
ϐ
2. If it proves impossible to do the
measuring the axial length using Hyperopic Eye biometry in the active child, it must
ultrasound make it nearly impossible for The hyperopic eye is prone to be done under sedation or general
the machine to auto-freeze (Figure 2). One produce postoperative refractive anaesthesia, in the operating room.
solution is to perform the measurement surprises for two reasons. If this is the plan, make sure that all
on the manual mode. Another solution is 1. The hyperopic eye is a short eye. This
ϐ
to mathematically adjust for component before the patient is sedated. If the
velocities after recording in the aphakic means that any error in measuring biometry is planned just prior to the
mode. However, the best way to record the axial length is proportionately actual surgery, ensure an adequate
axial length in the pseudophakic eye is to bigger than the same absolute error IOL library at hand.
use an optical biometer. in a longer eye. This is particularly Always remember to measure both
an issue with contact A-scan, and eyes.
A special circumstance of the can be avoided by using optical or
pseudophakic eye is one with a phakic immersion biometry. Growth issues
IOL implanted, also called the biphakic ʹǤ ϐ
eye. A formula to correct the measured changes in the Effective Lens The refractive error of young
axial length in this situation has been Position (ELP) is greater than that children does not change drastically as
described3. However, this formula seen in a normal sized eye. This they grow older, because the increasing
requires knowledge of the thickness (T) means that formula differences axial length is compensated by the
ϐ
ȋ Ȍ and optimization have a big role declining power of the crystalline lens5.
of the implanted phakic IOL to play. Ideally, optimization for ǡ ϐ
provide this changing compensation. In
The formula for correcting the
Insight Eye Clinic, Rajouri Garden, New Delhi
Dr. Saurabh Sawhney DOMS, DNB Dr.Ashima Aggarwal MS, DNB
30 DOS TIMES - NOVEMBER-DECEMBER 2016
CATARACT
Figure 3: Paediatric IOL undercorrections. implanting two IOLs. The base IOL is chances of achieving emmetropia.
placed in the bag, and carries dioptric Since there are many approaches
fact, it has been observed that the axial power equal to the projected emmetropic
elongation is larger when the young eye power in adulthood. The piggyback IOL to IOL power calculation, we will try
is pseudophakic6. provides the remaining power needed to understand the sources of error and
to produce emmetropia immediately evaluate any individual approach in that
A child who is emmetropic following postoperatively. As the child grows context.
IOL implantation will grow up to be older, the resulting myopia is taken care
highly myopic. This effect is particularly of by spectacles. Later, the piggyback Source of error in the post-
ϐ
ʹ IOL is removed to effectively counter
years of age, both in quantitative terms the myopic shift. This approach may refractive surgery eye
and in its ability to cause amblyopia7. be able to prevent amblyopia without
compromising on the unaided adult There are two fundamental sources
Some surgeons prefer to leave the refractive status. of error (Figure 4) when calculating IOL
eye hyperopic and wait for the myopic power for the post-refractive surgery
shift to take the child to adulthood Growing acceptance of IOL implants eye in the context of modern IOL power
emmetropia. Since most of the myopic in very young infants is likely to provide formulae. These are
ϐ more data and improve our understanding a. Errors in calculating corneal power.
life, targeted hyperopia is greater in the of the processes. The Infant Aphakia b. Errors in ELP estimation.
early years8. Figure 3 lists some of the
ϐ
recommendations. IOLs against contact lens correction in Errors in Calculating Corneal Power
children between the ages of 4 weeks In an average eye, the cornea
The obvious challenge here is and 7 months, and found no difference in accounts for about 45 D of refractive
preventing amblyopia. Contact lenses the visual acuity at the age of 4.5 years9. power of the eye. This refers to
can be used for refractive correction, The same study group is also addressing the power at the corneal apex. It is
progressively decreasing the power as a number of other issues relating to IOL traditionally measured by keratometry,
the child grows older. There is, however, implantation in the very young.
ϐ
the possibility of missing the target of points on the anterior corneal surface.
emmetropia at adulthood despite the Paediatric Calculations ϐ
best planning. estimate the anterior corneal curvature.
Once a target refractive error Keratometers calculate the corneal power
It has also been suggested that the has been decided for a particular eye, by applying a keratometric index to this
immediate target can be emmetropia, calculations need to be performed. curvature.
thereby preventing amblyopia. As the Unfortunately, no formula has been
ϐ
child grows older, myopic correction
ϐ
value, typically set at 1.3375. It presumes
is provided till refractive stability is eye. We must therefore recourse to a constant ratio between the anterior
achieved, at which point an IOL exchange, standard IOL power formulae. Since and posterior corneal curvature and
a piggyback IOL, or myopic LASIK can the original data-sets which were used combines these two different refractive
be considered. This approach offers to develop these formulae comprised surfaces into one single entity. This works
emmetropia following surgery, as well of adult eyes only, the performance of well because it allows the keratometer
as during adulthood. However, it has the these formulae is suboptimal when used to estimate the corneal power from
disadvantage of requiring two surgeries for the paediatric eye. There is greater the anterior corneal curvature alone.
to achieve this end. variability across all formulae, with the Following myopic LASIK or PRK, the
error of prediction lying in the range of
ϐ
A different approach consists of 1.0 to 1.8D10. However, use of optimized posterior surface remains unaltered.
constants has been shown to decrease This changes the ratio between the two
the prediction error11. In general, modern surfaces, thus invalidating the composite
theoretical formulae seem to be placed keratometric index.
roughly equally in terms of accuracy in There is a second source of error in
predicting paediatric IOL power12. measuring corneal power. Keratometers
measure the paracentral cornea rather
POST REFRACTIVE SURGERY EYES than the central. Since the normal
cornea is steeper at the apex, fudging
Patients who have a lower tolerance of the curvature is done to estimate
for spectacles are the ones who undergo the central, apical curvature. Following
ϐ
Ǥ refractive surgery for myopia, the central
Ironically, when these patients need
ϐǡ
cataract surgery, the process of biometry instruments recording paracentrally. This
is made much more complicated by the is an error of measuring the radius, and
same refractive surgery. The situation is is independent of the keratometric index
murkier because there are many types of error.
ǡ
ϐ
Both these errors produce an over-
eye in a different manner. estimation of the central corneal power.
Since greater power is falsely attributed
Fortunately, a lot of research has to the cornea, IOL power calculations
been done in this area, improving the produce correspondingly lower
www. dos-times.org 31
CATARACT
Figure 4: 5QWTEGU QH GTTQT KP VJG RQUV TGH UZ G[G sets can possibly reduce the accuracy, The Jarade Method has been
or even make it worse than the raw
ϐ
estimates, resulting in hyperopia post- formula. For this reason, it is important eye, using corneal radius (in mm) as
operatively. ϐ
measured by the IOL Master.
before applying it.
The logic reverses when there is Using data from Example 1,
central steepening following hyperopic Getting the corneal power right – KJARADE = (1.3375 + 0.0014x (-5.16) –
LASIK or thermokeratoplasty for 1) / (8.182/1000) = 40.37 D
hyperopia, resulting in underestimation using historical data Here, the corneal radius used
of the corneal power. This consequently has been calculated from the present
leads to overestimation of the IOL power A number of methods requiring keratometry reading (Figure 5). The
needed for emmetropia, and the patient clinical history have been proposed. The refractive change (-5.16 D) is derived by
ends up with a myopic error.
ȋ Ȍ
ϐ
transposing -5.5 D to the corneal plane,
instance of one of these suggestions13. assuming a vertex distance of 12 mm.
Errors in ELP estimation The basic premise is that any refractive
change in the eye following refractive Getting the corneal power right –
Modern third-generation formulae surgery resides entirely in the cornea.
use the measured corneal curvature to As per the CHM, the true corneal power without historical data
estimate the height of the corneal vault, can be calculated by adding the refractive
and thereby link the ELP estimation to change to the measured corneal power. Very often, historical data is not
the keratometry reading. Correction for This requires knowledge of the refractive available. Sometimes, it is available but
ϐ
status prior to the refractive surgery, and not accurate, especially in context of the
without changing the anterior chamber the post-correction refractive status. The high precision of modern measurement
depth. This leads to a false low estimate of refractive change should be calculated devices. Finally, there may have been a
ELP, with the formulae predicting a more after vertex correction to the corneal shift in the corneal status in the years
anteriorly placed IOL. The actual position plane. Average keratometry and spherical following the surgery, so that historical
of the IOL is in line with the preoperative equivalent refraction values are used. data may not be able to portray an
keratometry. The erroneous anterior accurate picture. For these reasons,
projection leads to an underestimation KCHM = KPRE + Refractive Change opinion is gradually shifting to making
of the IOL power. This error compounds EXAMPLE 1 For instance, consider the best of the currently available data.
the error of corneal power measurement, a patient whose current keratometry
pushing eyes with earlier myopic is (40.5 / 42.0) D, and documents show Many methods have been suggested
correction towards hyperopia. a pre-surgery keratometry of (44.5 / to estimate true corneal power using
45.5) D, previous refractive error of current measurements. The oldest of
The reverse occurs in eyes that -6.0D, corrected to -0.5D by the refractive these is perhaps the Contact Lens Method,
have undergone hyperopic correction, surgery. which was described by Fredrick Ridley as
resulting in a myopic surprise when the Here, KCHM = 45.0 + (-5.5) = 39.5D early as 1948. The basic principle is that
surgeon aims for emmetropia. The Ronje Method requires placing a hard contact lens of zero power
the refractive change, but not the will not change the manifest refraction
The Haigis formula does not use the preoperative keratometry values. This of the eye, if the base curve matches the
keratometry as an input variable for the
ϐ
corneal curvature exactly.
ELP. Instead, it uses the actual, measured for post-LASIK eyes. As per Ronje,
anterior chamber depth to project the IOL KRONJE = KPRESENT FLAT + 0.25 X Refractive This method, while fairly reliable,
position. Therefore, the Haigis formula is Change is not very popular because it is
not subject to this source of error. KRONJE = 40.5 + 0.25 x (-5.5) = 39.125 cumbersome, requires a special set of
D, using data from Example 1. contact lenses and visual acuity of at least
Dealing with the errors 6/24, which excludes a large number of
Adjusting the keratometric index cataract patients.
It is important to remember that
in the tangle of numerous formula using historical data Other methods to estimate true
ϐ
ǡ
ϐ
ϐ
A related approach is to modify the corneal power
clinical situations. The use of these
ϐ
nomograms or formula tweaks will only caused by the refractive surgery. The These methods use current central
improve things if they are applied to the Savini method, the Camellin method and keratometry readings. They should only
appropriate eye. Extrapolating to other the Jarade method all adopt this strategy, be used for myopic LASIK corrections.
and are all very similar in their structure.
The Maloney Central Topography
The Jarade Method requires Method, described in 1998, estimates
knowledge of the refractive change true corneal power as,
induced by the surgery and the average
radius of curvature of the cornea at the KMALONEY = 1.1141 x Topography K –
present moment. Please note that the 5.5
Jarade Method is different from the Jarade
Formula.
ʹͲͲ͵ ϐ
this equation, changing the constant
KJARADE = ((1.3375 + 0.0014 x to 6.1 from 5.5, and in 2007, Savini et
Refractive Change at corneal plane) – 1) / al reported superior outcomes using a
(Corneal Radius/1000) constant value of 4.98.
The Shammas No History Method14
is similar in approach, but uses manual
32 DOS TIMES - NOVEMBER-DECEMBER 2016
CATARACT
Figure 5: Radius from Dioptres. Figure 6: Haigis-L. calculation using the following equation:
IOL Power (P) = PPREOPDATA – Refractive
keratometry readings. The double-K modification
KSHAMAS = 1.14 x Manual Keratometry Change / 0.7
Two variable formulae use the See Figure 7 for an example.
– 6.8 keratometry values at two places. The Masket method requires the
Direct measurement of true corneal a. Vergence Equation, to estimate the
knowledge of postoperative keratometry
power
ϐ
and the refractive change induced by the
Theoretically, the best way to curvature on the IOL power laser vision correction18. It also requires
estimation. calculation of the IOL power as per
calculate true corneal power would be b. ELP estimation, which determines existing data, to which an adjustment
to record the anterior and posterior the position, and therefore the is added. For the purpose of IOL power
curvatures at the corneal apex, and effective power of the lens within the calculation using current data, Masket
use the actual refractive index of the eye. recommends using Holladay 1 formula
Ǥ
ϐ The double-K strategy uses the
ȋ εʹ͵ǤͲ Ȍǡ
to do just that. Actual measurements original keratometry (pre-refractive and Hoffer Q for hyperopic ones (AL<23.0
offer the advantage of not requiring surgery) to estimate the ELP, and mm). The adjustment can be calculated as
any pre-operative data as well as being the present-day keratometry for the follows.
independent of any changes on the vergence equation. This approach,
corneal curvatures that have taken place therefore, separates the two places where IOL Adjustment = (Refractive Change x
over time after the refractive surgery. keratometry is used. It can be used with -0.326) + 0.101
formulae such as the SRK/T, Holladay and
Determination of the true central Hoffer Q. IOL PowerMASKET = IOL PowerCurrent Data
corneal power addresses only one source ϐ + IOLAdjustment
of error. The issue of ELP estimation Aramberri, who conducted a pilot study
remains. Even in virgin eyes, ELP of nine eyes and was able to demonstrate Methods not requiring clinical
estimation has been shown to be the ϐ
leading cause of error in IOL power performance of the SRK/T formula. As of history
calculations. ǡ Ǧ ϐ
formulae is not readily available on all As per the Ianchulev Method, the
Tackling the ELP issue biometry machines, but free software can aphakic refraction carried out on the
be easily downloaded from the internet operating table can be used to estimate
Among the modern IOL power (see resources). the IOL power required19. A hand-held
calculation formulae, the Haigis formula The use of this approach requires automated refractor is used after the
is unique in not using the keratometry the knowledge of pre-refractive surgery cataract has been removed, and the
value for ELP estimation. Therefore, it is keratometry. Even if this is not available, power is calculated as per
reasonable to presume that once a true a presumptive keratometry (43.5D) can
corneal power value is available, the Haigis be used as a substitute. This is known IOLIANCHULEV = 2.02 x Aphakic
ϐǤ ʹͲͲͺǡ as the no history double-K approach, Refraction + (A-118.4), where A is the
The Haigis-L formula was introduced and it still produces better results than A-constant.
ϐ
using the formulae with only present day
laser refractive surgery for myopia15. This keratometry. This approach is remarkably simple,
formula consists of an equation (Figure 6) and obviates the need for measuring
to correct the keratometry as measured Adjusting the formulae keratometry and axial length. There are
by the IOL Master. The rest of the Haigis concerns about the extent of anterior
equation remains the same. The double-K method is one way to
ϐǡ
adjust the formulae for better outcomes. maintain a large IOL inventory, but early
For post-RK eyes, the directly Other strategies have also been proposed. results have been promising. There may
obtained IOL Master K values combined be role for adjunctive use of this strategy,
with the basic Haigis formula set for Methods requiring clinical history along with other approaches.
target refraction of -1.00 D have been
shown to produce good results16. The Feiz-Mannis Formula involves The Mackool Secondary Implant
calculating the IOL power in the Method is similar in form to the Ianchulev
However, the Haigis or Haigis-L normal fashion, using preoperative equation20.
formula will only perform well after keratometry17. This produces the IOL
optimization. power that would have been needed IOLMACKOOL = 1.75 x Aphakic Refraction
had the eye not undergone a refractive + (A-118.84), where A is the A-constant.
Ǥ ϐ
surgery is then incorporated into the The author suggests shifting the
patient out of the operating room for
refraction, which is done half an hour
after the cataract is extracted. The patient
is then shifted back to the operating room
for IOL implantation. This approach may
not be suitable in terms of logistics and
maintaining a sterile environment for the
eye.
Both the Ianchulev and Mackool
methods are seriously hampered by low
subject counts. The Ianchulev equation
was derived on a database of 20 patients
and tested on a further 16, of which only 6
www. dos-times.org 33
CATARACT
Figure 7: 'ZCORNG Preoperative refractive astigmatism when the residual astigmatism needs
consists of lenticular and corneal to be close to zero, as in toric multifocal
eyes had previously undergone refractive astigmatism. The lenticular component implantation. One can measure the actual
surgery. The Mackool equation has been is eliminated by the extraction of the posterior corneal astigmatism by means
derived on the strength of data from 12 cataract. Therefore, when considering a
ϐ
eyes only. toric IOL implantation, the surgeon must the Pentacam. However, only a few toric
correct only corneal astigmatism. calculators permit the use of this data in
Intraoperative aberrometry is a their calculations. In general, it has been
high-end version of the same strategy. There are two elements involved observed that eyes with ATR astigmatism
ϐ
ǡ when calculating IOL power for toric IOLs (horizontally steep cornea) tend to
Refractive Analysis (ORA) system, has 1. Spherical power require greater toricity at the IOL plane
been in use since 2012. The device is 2. Cylindrical power than eyes with WTR astigmatism.
attached to the operating microscope and
offers real time measurements, including The spherical power is calculated THE LAST WORD
data on astigmatism. Apart from use in just as one would normally calculate for
eyes that have had previous refractive a non-toric IOL. The aim is to achieve Special situations make the task
surgery, it is also being used for routine emmetropia, or slight myopia. ϐ
ǡ
ǡ ϐ
ϐ
Ǥ
IOL placement. HOLOS IntraOp is the To calculate the toric power needed, points to success are understanding and
latest wavefront aberrometer available. several component calculations are applying knowledge. One must know how
required. The pre-existing corneal special circumstances deviate from the
ϐ
astigmatism and the Surgically Induced normal, in what way can the differences
intraoperative systems is the variability Astigmatism (SIA) are combined by
ϐ
ϐ
associated with a dynamic intraoperative vector addition to generate the expected of IOL power, and what are the best
ocular environment. Another major issue postoperative astigmatism. This new strategies to bring the calculations back
is the cost of the equipment. vector represents the target vector for on track.
implanting the toric IOL. The orientation
Which approach to use for the post of the toric IOL should be along the axis Web resources
refractive surgery patient? (Figure 7.5) of this target vector. The magnitude of
the target vector indicates the cylindrical 1. The free software mentioned in this
With so many strategies, there is correction required at the corneal plane. article can be downloaded from any
bound to be some confusion on the best This needs to be transposed to the IOL of these sites. You may also contact
course to take. Unfortunately, there is no plane by using a refractive factor. As [email protected]
consensus on this. The ASCRS website a rule, online calculators have been or Facebook/Ophthalmic Calculators
offers a tool for calculating the IOL power using 1.5 as the refractive factor, though for the same.
as per different protocols, and also offers recently there has been interest in the use a. http://saurabhsawhney.wix.
minimum, maximum and average IOL
ϐ
Ǥ com/calculators
power from those calculated. Finally, it This latter strategy makes sense, because b. www.softpedia.com/publisher/
is for the surgeon to decide which IOL the refractive factor depends upon the Dr-Saurabh-Sawhney-Dr-
power to implant. A good understanding ϐ Ǥ Ashima-Aggarwal-100741.html
of the way these protocols function c. http://www.insighteyeclinic.
should hopefully illuminate the decision The calculation of cylindrical in/SIA_Calculator.php
making pathway somewhat. power is made easy through the use of
online calculators. Every company that REFERENCES
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The use of toric IOLs has proven to Ǧϐ
Ǥ Benson MT, Kirkby GR. Biometry of the
be a reliable and effective strategy to To obtain good results, it is recommended
Ǧϐ ǣ Ǥ ȋ ȌǤ
manage astigmatism. that surgeons should calculate their own ʹͲͲʹǢͳǣʹǦ͵Ͳ
values for SIA.
2. S Kunavisarut P, Poopattanakul P,
If additional measures are planned Intarated C, Pathanapitoon K.Accuracy
to reduce corneal astigmatism, such as and reliability of IOL master and A-scan
Limbal Arcuate Relaxing Incisions (LARI) immersion biometry in silicone oil-
or opposing clear corneal incisions ϐ Ǥ ȋ ȌǤ ʹͲͳʹǢʹǣͳ͵ͶͶǦͺ
(OCCI), they need to be factored into the
calculations. The amount of expected 3. Hoffer KJ. Ultrasound axial length
astigmatic change should be subtracted measurement in biphakic eyes.J
from the target vector as previously
ʹͲͲ͵ǢʹͻǣͻͳǦͷ
calculated, to arrive at the new target
vector. 4. Pitault G, Leboeuf C, Leroux les Jardins
S, Auclin F, Chong-Sit D, Baudouin C.
The importance of posterior corneal Optical biometry of eyes corrected
astigmatism is the current buzzword. by phakic intraocular lenses.J
ϐ ϐ
Ǥ ʹͲͲͷǢʹͺǣͳͲͷʹǦ
as 0.5 D to 0.75 D. Such a magnitude of
ϐ
5. Gordon RA, Donzis PB. Refractive
dealing with low initial astigmatism, or development of the human eye. Arch
Ǥ ͳͻͺͷǢͳͲ͵ǣͺͷǦͻ
6. Magli A, Forte R, Rombetto L. Long-term
outcome of primary versus secondary
intraocular lens implantation after
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simultaneous removal of bilateral 11. Vasavada V et al. Comparison of Haigis Formulas.Ophthalmology.
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Ǥ Ǥ ʹͲͳ͵Ǣʹͷͳǣ͵ͲͻȂͳͶ paediatric eyes. Eye (Lond). 2016 Sep. 17. Feiz V., Mannis M.J. Garcia-Ferrer F et
7. Al Shamrani M, Al Turkmani S. Update 12. Nihalani BR, VanderVeen DK. al. Intraocular lens power calculation
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in children. Saudi Journal of calculation formulae in pediatric eyes. myopia and hyperopia a standardized
Ǥ ʹͲͳʹǢʹǣʹͳǦͷǤ Ǥ ʹͲͳͲǢͳͳǣͳͶͻ͵ǦͻǤ
Ǥ ʹͲͲͳǢʹͲǣͻʹǦͻǤ
8. O’Keefe M1, Fenton S, Lanigan B. 13. Hoffer KJ.Intraocular lens power 18. Masket S, Masket SE. Simple
Visual outcomes and complications calculation for eyes after refractive regression formula for intraocular lens
of posterior chamber intraocular lens keratotomy. J Refract Surg. poweradjustment in eyes requiring
ϐ Ǥ
ͳͻͻͷǢͳͳǣͶͻͲǦ͵Ǥ cataract surgery after excimer laser
Ǥ ʹͲͲͳǢʹǣʹͲͲǦ 14. Shammas HJ1, Shammas MC, Garabet photoablation. J Cataract Refract Surg.
11. A, Kim JH, Shammas A, LaBree ʹͲͲǢ͵ʹǣͶ͵ͲǦͶǤ
9. The Infant Aphakia Treatment Study L. Correcting the corneal power 19. Ianchulev T, Salz J, Hoffer K, Albini T,
Group. A Randomized Clinical Trial measurements for intraocular lens Hsu H, Labree L. Intraoperativeoptical
Comparing Contact Lens to Intraocular power calculations after myopic laser refractive biometry for intraocular lens
Lens Correction of Monocular Aphakia in situ keratomileusis.Am J Ophthalmol. power estimation without axiallength
during Infancy: HOTV Optotype Acuity ʹͲͲ͵Ǣͳ͵ǣͶʹǦ͵ʹǤ and keratometry measurements. J
at Age 4.5 Years and Clinical Findings 15. Haigis W. IOL calculation after
Ǥ ʹͲͲͷǢ͵ͳǣͳͷ͵ͲǦǤ
at Age 5 years. JAMA ophthalmology. refractive surgery for myopia: the 20. Mackool RJ, Ko W, Mackool R.
ʹͲͳͶǢͳ͵ʹǣǦͺʹǤ Haigis-L formula. J Cataract Refract Intraocular lens power calculation after
10. Andreo LK, Wilson ME, Saunders RA. Ǥ ʹͲͲͺǢ͵ͶǣͳͷͺȂ͵Ǥ laser in situ keratomileusis: Aphakic
Predictive value of regression and 16. Geggel HS.Intraocular Lens Power refraction technique. J Cataract Refract
theoretical IOL formulas in pediatric Selection after Radial Keratotomy: Ǥ ʹͲͲǢ͵ʹǣͶ͵ͷǦǤ
intraocular lens implantation. J Topography, Manual, and IOLMaster
PediatrOphthalmol Strabismus Keratometry Results Using
ͳͻͻǢ͵ͶǣʹͶͲǦ͵Ǥ
Financial Interest: ϔ
Ȁ
Ǥ
Dr. Shroff’s Charity Eye Hospital ICARE Eye Hospital & Post Graduate Institute
Eye Bank wins An NABH Accredited Eye Hospital in National Capital Region
The BMJ South Asia Healthcare award 2016 with more than 450 OPD patients a day
20th November 2016 Invites applications for
Congratulations Dr. Manisha Acharya, winner of the Vitreo Retinal Surgeon
prestigious BMJ South Asia Healthcare Award as Quality
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Tel : +91 (0120) 2477600-02, Helpline : +91 9811880015
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www. dos-times.org 35
GLAUCOMA
RECENT ADVANCES IN PERIMETRY
J.S. Bhalla, Pooja Lal
Adiagnosis of glaucoma requires a clinical ϐ
triad: elevated intraocular pressure, structural greater than for standard automated perimetry.
ǡ ϐ
ϐ
Ǥ Disadvantages of SWAP are that it is associated with
For the past few decades, white on- increased patient fatigue and long adaptation time plus cataract
may lead to a false appearance or falsely appearing progression
white automated perimetry (W-W) has been ϐ
Ǥ
ǦǦ
ȋ Ȍ
considered the test of reference for glaucoma diagnosis and Ǧ ϐ
monitoring. variability of the threshold. The bright yellow background is
Standard automated perimetry, which tests the visual very intense and the blue stimuli are hard to perceive.
ϐ
ȋ Ǧ
Ȍ
ϐ
ͶͲΨ FREQUENCY DOUBLING TECHNOLOGY PERIMETRY
retinal ganglion cells (RGCs) have been lost. It is preferable to Frequency doubling technology (FDT) perimetry (Figure
detect damage at earlier stages of ganglion cell loss, given the ͳȌ ϐ
irreversible nature of vision loss in glaucoma. Newer perimetry ϐ
techniques are as follows temporal frequency. This phenomenon essentially creates an
Ȉ
ȋ ǡ image that appears double its actual spatial frequency3,4.
SWAP) FDT does not require a judgment on behalf of patients
Ȉ Ǧ ȋ Ȍ regarding whether doubling is present, rather FDT simply
Ȉ
ȋ Ȍ measures grating contrast detection thresholds for sinusoidal
Ȉ ȋ Ȍ stimuli that fall within the frequency-doubling range.
Ȉ Consequently, performance on this task is likely to be mediated
Ȉ
ȋ Ȍ by a combination of retinal and cortical mechanisms. FDT
Ȉ ȋ Ȍ
ϐ
Ȉ ȋ Ȍ
ϐ
SHORT WAVELENGTH AUTOMATED PERIMETRY ϐ ǦǦ Ǥ
(SWAP) appears to have reduced patient variability compared with
white-on-white perimetry, implying that FDT should have
Blue-on-Yellow Perimetry (B-Y), also known as Short
ϐ Ǥ
Wavelength Automated
ϐ
FDT is also effective in detecting
ϐ
Perimetry (SWAP), can detect
ϐ 40% of ganglion cells have been lost. with optic neuropathies but
a reduction in differential ϐ
Hence, newer techniques which may ϐ
Ǧ
light sensitivity is seen with detect glaucoma earlier are required. on-white perimetry. A second
standard white-on-white
(W-W) perimetry. It has a very generation FDT perimeter, the
ϐ
Ǥ Humphrey Matrix utilises smaller grating patches than the
In SWAP, a yellow background light bleaches or suppresses original FDT to enable standard 24-2 and 30-2 test patterns.
the red and green cones while blue cones are stimulated by a
ϐ
blue stimulus. Blue on Yellow perimetry isolates and tests those generation FDT, which evaluates contrast sensitivity for only 17
cells, which are thought to be lost early in glaucoma, thereby or 19 test locations. This improves the ability of FDT to detect
detecting glaucomatous retinal ganglion cell death/dysfunction
ϐ
Ǥ
earlier than W-W perimetry, which tests all retinal ganglion cell ϐ
Ǥ
populations1,2. There are two different presentation patterns using the
ǡ ϐ original FDT perimeter. The C-20 pattern tests 17 different
(530 nm ) is used at a luminance of 100 cd/m. For the stimulus, points within a central 20-degree radius (4 targets in each
a large Goldmann Size V (about 1.7 degrees diameter) light with quadrant and one central target), while the N-30 pattern
ϐ ȋͶͶͲ Ȍ incorporates two additional nasal targets above and below the
and a 200 millisecond stimulus duration is used. With these horizontal meridian (Figure1b). Both patterns can be used in
ϐ
ǡ
Ǥ
ϐ
cones resulting in a dynamic range between 18 dB at the fovea FDT test are proven to be comparable to SAP.
and 12 dB at 20° eccentricity. The second generation Humphrey Matrix FDT Perimeter
The size of defects on Blue on yellow perimetry are usually has the following salient features. It includes the ability to
larger than those observed for standard automated perimetry ϐǤ
www. dos-times.org 37
GLAUCOMA
Figure 1a: FDT Perimeter Figure 1b: FDT Perimeter printout ϐ Ǥ
Once the best retinal area is selected,
uses smaller targets that are presented ϐ
patients are asked to move their gaze
along a grid. In addition, greater spatial
Ǥ Ǥ
ϐ towards that direction, while audio
resolution is available with 24-2, 30-2, advanced macular degenration5,6. signals guide them to the desired target.
10-2, and macular threshold tests. This process is called biofeedback, and
The retinal area used by eccentric is based on the theory of brain plasticity.
During FDT perimetry testing, the viewers to substitute the foveal vision With several training sessions, some
ϐ
is known as the Preferred Retinal Locus patients are able to gain better use of
targets and instructed to press the (PRL). In Microperimetry systems, the their peripheral vision.
response button at the appearance of fundus (eye) is imaged in real time,
each stimulus. Due to the relatively large while an eye tracker compensates eye The advantages over conventional
targets used in FDT perimetry refractive movements during stimuli projection, perimetry include fundus tracking
errors up to 6 diopters are not considered allowing correct matching between features and the co-registration of the
ϐ
ϐ
Ǥ expected and projected stimulus position perimetric results with fundus imaging.
Patients are able to wear their own onto the retina. Simultaneously, the The disadvantages are lack of provision
corrective lenses while performing the eye tracker plots the retinal movement for cylindrical refractive correction in
test. ϐ ϐ ϐ
ϐ Ǥ and that it does not allow for adaptive
FDT perimetry is completed faster Some microperimetry instruments threshold-estimating strategies
than using the SAP SITA-FAST strategy. calculate 2 different PRL zones during the
FDT has both lower intra- and intertest examination. To create the fundus image HEAD MOUNTED PERIMETER
variability compared to SAP, which an infrared telecamera is used.
suggests it may be a useful test to monitor Most of the perimeters are
Ǧ ϐ Ǥ In patients with central vision loss, stationary type devices that need to be
ǡ ϐ
ǡ microperimetry experts are able to
non-operator dependent . analyse the eccentric retina in order to
Reduced sensitivity on FDT
perimetry has been reported in patients
with diabetes suggesting a role for FDT
perimetry in screening for diabetic
retinopathy.
MICROPERIMETRY
Microperimetry, sometimes called
Fundus related perimetry, is a type of
ϐ
technologies to create a “retinal sensitivity
map” of the quantity of light perceived in
ϐ
Department of Ophthalmology, DDU Hospital, New Delhi
Dr. J.S. Bhalla MS, DNB Dr. Pooja Lal DNB
38 DOS TIMES - NOVEMBER-DECEMBER 2016
GLAUCOMA
used in a dim testing room with light Figure 2: The head-mounted perimeter imo. testing optokinetic nystagmus and
control. In addition to issues such as simulating migraine auras. Each HRP
portability and space restriction for the Furthermore, astigmatic correction could test target consists of a bright circular
standard automated perimeters, patients be achieved as well using an additional core surrounded by dark borders (Figure
with special physical conditions may removable magnetic cylindrical lens 3b). The dimensions and luminances are
ϐ
system. The actual distance between the carefully calculated to make the target
to physically adapt themselves to the center of the cornea surface and the lens invisibly melt into the background if
stationary type devices during the test. is 17.5 mm and patient’s viewing distance unresolved. The short test distance,
Therefore, a patient-oriented perimeter is set at 1 meter. 0.16 m, causes powerful foreshortening
ϐ of peripherally presented targets,
the test is a pressing need and a head- With both eyes open during testing, and powerful parallax effects in the
mounted perimeter appears to be ideal. A the problem of Ganzfeld blankout or monitor’s glass envelope. These effects
prototype has been described below. rivalry as occurs during SAP can be are compensated in software, so the rings
solved. Because the test target is randomly always appear as true rings of correct
A portable head-mounted perimeter presented to either eye, patients will not angular dimensions. 14 different sizes are
named “imo” (Tokyo, Japan) has been be aware of which eye is being tested used, stepped by 0.1 of a logarithmic unit
developed which allows patients to during the test. Therefore, the binocular (1 decibel, dB). The largest ring nearly
be tested with better comfort at any random single eye test can also be used ϐ Ǥ
location7. Moreover, as a unique feature for detecting feigned blindness. Its VF advantage of using different-size targets
of this device, the test target is randomly results highly compatible to those by the is that the test can begin with a check
presented to either eye without occlusion HFA in patients with glaucoma. for the presence of vision in extended
and without the examinee being aware of areas, even full quadrants. If no response
which eye is being tested (the binocular HIGH PASS RESOLUTION is obtained, that area will not be further
random single eye test). tested. Normal examination time is
PERIMETRY about 5 minutes. Fixation is monitored
The head-mounted perimeter imo by occasionally projecting a target in the
(Figure 2) consists of a main perimeter The fact that presence of letters can ϐ
unit, a user control tablet, and a patient be recognized at a much longer viewing
ϐ Dz dz
response button. A computer unit and distance than that required for resolving ϐ Ǥ
a lithium-ion battery are built in the the letters is the basic principle behind complaints are sounded on errors.
perimeter unit (W22 cm × D38 cm × H24 High Pass Resolution Perimetry (HRP)
ǡ ͳǤͺ ȌǤ ϐ or Ring Perimetry8. The application of Thresholds are determined by
operates the control tablet connected to so-called high-pass spatial frequency up-down stepping procedures, using
the perimeter unit by Wi-Fi and patient’s ϐ ǯ
different-size steps in different phases
responses are obtained using the resolution thresholds into coincidence of the examination. The different phases
response button connected by Bluetooth. and makes for a very simple test task, also are devised to retain a maximum of
in peripheral vision. High-pass resolution information if the test is aborted prior
The right and left optical systems targets are easily generated in computer to completion. There are two convenient
in the perimeter unit are completely graphics. HRP or “ring” perimetry abortion points for patients with limited
separated and stimulus presentation was introduced in 1987. It utilizes endurance. One point occurs when
and pupil monitoring are independently dual monitors driven by a personal thresholds have been obtained for the
performed for each eye within 35° from computer (PC), arranged for maximum fourquadrant centers (which requires
the fovea. A telecentric optical system is physical comfort for both the patient less than 1 minute of testing time),
introduced to equalize the central and and the examiner (Figure 3a). The ring another occurs midway, when one-half
peripheral light intensities. ϐ of the locations have been tested, after
ǡ ϐ about 2.5 minutes. At this point the test
A test target luminance of 0.032– include several feedback features, and the stops for rest.
3183 cd/m2 (0.1–10000 asb) with a ϐ
Ǥ
background luminance of 10 cd/m2 (31.4 The latter features help to make the HRP tests 50 locations inside the
asb) is generated using 10 bit resolutions, patient feel in command of the procedure. ͵Ͳι
ϐǤ
and the stimulus duration was 200 The use of an ordinary PC makes it are distributed in a pattern reminescent
msec. The temporal resolution of the possible not only to serve mundane PC of normal isopters (Figure 3c). This
transmissive LCD display is 60 Hz and the tasks but also to address a host of non- is calculated to facilitate both visual
stimulus intensity reached to a constant perimetric diagnostic tasks, for example,
ϐ
luminance level within one frame (1.67 patterns and statistical analysis of
msec). Test targets used the Goldmann results. Results are plotted as threshold
size I to V, or any other optimal sizes and target sizes, showing precisely what the
shapes available. patient could see in each location. HRP as
described above has undergone two major
During the examination, both pupil revisions, motivated by improvements
images are continuously monitored at a in PC display technology. Version 1 was
frame rate of 30 Hz and the images could actually ahead of off-the-shelf technology
be used for an eye tracking system. Using and required cutting and soldering inside
the spherical lens adjustment dials a the graphic card. The latest version, No. 3,
spherical lens correction within the range
of -9 to +3 diopters can be performed
without using any additional trial lenses.
www. dos-times.org 39
GLAUCOMA
ab
Figure 3a: HRP Set up Figure 4a: Rarebit Perimetry Stimulus Pattern. Figure 4b: Rarebit Perimetry Print out
Figure 3b: HRP Test Target is carried by pairs of minuscule bright reduction in hit rates. For example, a 10%
ȋDzdzȌǡ ϐ
ϐ ǡ ǡ
Figure 3c: HRP Printout against a dark background. The number result in a 10% reduction in rarebit hit
remains unchanged since 1998 and still of dots is very small (“rare bits”), hence rate, to 90%.
works diligently in many places around the colloquial test name, “The Rabbit
the world, both in clinics and in research Test”. RBP is implemented in computer
settings. graphics, in a single-monitor set-up. The
Rare Bit Perimetry depends on software runs under Microsoft Windows.
The dual monitor HRP set-up minute stimuli (“rare” bits or “microdots”) The test requires a modern liquid crystal
ϐ
and it replaces the conventional display (LCD) and 0.5 m test distance (1
ϐ thresholding approach (“How well do you
Ǧ ϐȌǤ
graphics cards and monitors. A single- see here?”) with simple checks for the LCD technology and the long test distance
monitor version (Ring-1) was produced presence of function (“Is there a receptive are crucial to achieve the required
but proved somewhat awkward to use in ϐ ǫ ǫ ǫdzȌǤ
ǡ stimulus parameters (dot size = one-half
practice. Patient satisfaction is more with rather than gauging the level of function, Ǣ
HRP. HRP is known to perform well in RBP probes the integrity of the neural white dots on a black background). A 15”
glaucoma and optic neuropathy contexts. matrix9. LCD occupies no more than 30° of visual
Being a resolution-type test, it is sensitive angle at 0.5 m distance but by moving
to cataract. The animation schematically ϐ
RAREBIT PERIMETRY illustrates these ideas. The hexagons it is possible to access a 60x45° visual
represent a small set of retinal receptive ϐ Ǥ
ǡ ϐ
In Rarebit Perimetry, the information ϐǡ
ͳͲ
ȋ Ǥ
ϐ
selected) are damaged (black) (Figure ϐ
4a). A DLS test target (white circle) ϐ
Ǥ ǡ
typically envelops numerous receptive ϐ
ϐ
ϐ Ǥ
return a normal result with this small
degree of damage. Rarebits (red dots) The simplest implementation would
are very much smaller. With multiple be to present microdots one by one but
presentations in ever-new locations, RBP presents pairs of dots, spaced by
10 per cent of the rarebit presentations 4°, in the interest of saving on test time.
ϐ Hence, for each presentation, the subject
and so go unseen. has to indicate whether he or she saw 1
dot, 2 dots, or none at all. This is done by
RBP uses a set number (24) of clicking, double-clicking, or not clicking
rectangular test areas (Figure 4b) and on the computer mouse.
probes repeatedly for the presence
of vision within each area, in new The test provides feedback, both
locations. Because the retina normally visually and by sound. The test runs over
ϐǡ all 24 test locations once. This takes less
the expected outcome is that all rarebits than a minute. The test then stops for as a
should be seen (100% “hit rate”, or long a pause as required in the individual
nearly so: provision has to be made for case. It is then repeated. The number of
the blindspot and angioscotomas, and repeats is under the operator’s control and
for lapses of attention). From the RBP govern the precision of measurements.
point of view, the normal “Hill of Vision” Five passes may be a good compromise
ϐ
Ǥ ǡ between patient tolerance and clinical
most disorders of the visual system needs. Results are plotted in a gray-scale
result in more or less extensive losses or format. The more dark rectangles there
ϐǤ
ǡ ǡ Ǣ
there should appear corresponding the darker the rectangles, the more severe
Dzdz
ϐ the damage. Various simple statistics are
where rarebit presentations would not be provided automatically.
seen. The spatial density of holes would
be expected to cause a proportionate In addition to the regular 30°
Ǧϐ ǡ
40 DOS TIMES - NOVEMBER-DECEMBER 2016
GLAUCOMA
ϐ Ǥ
ϐ ͵Ͳ ʹͶι
ϐǡ
ϐ Ǥ
test is used at a 2 m test distance where
the test area subtends 8 x 6°.
RBP holds considerable promise
for the evaluation of glaucoma and
neuro-ophthalmological conditions.
Similarly, the inbuilt Rarebit Fovea
Test, RFT, appears useful in macular
conditions, including age-related macula
degeneration and diabetes.
NEW RARE BIT TESTS Figure 5: Motion Detection Perimetry Stimulus pattern
The 30” WQXGA LCD screens run perimeter by measuring luminance number of pixels from target center and
ϐ sensitivity across a 9 by 9 degree custom reaction times are then calculated.
viewing distance. Unfortunately, these grid of 100 test locations with a separation
screens are quite expensive and so is the between adjacent locations of 1 degree. Motion detection perimetry is
associated hardware. High spatial resolution perimetry in resistant to blur up to six diopters. The
ϐ sensitivity appears to be superior to
Next is a prototype for a pocket luminance sensitivity loss, not suspected conventional automated perimetry but
ǡ Ɋ Ǥ with conventional perimetry. High spatial
ϐ
Ǥ
This device provides a Hit Rate estimate resolution perimetry also demonstrates
from 60 probe locations inside 30° in less reproducible areas of sensitivity loss Motion detection perimetry is
than one minute of testing time, including in some glaucomatous eyes in areas of performed in a darkened room. The
control presentations. ϐ
test background is composed of 10,000
with conventional programmes. This randomly positioned white dots with
The MacuBit test uses 0.5’ diameter technique of high spatial resolution 3.26% of pixels illuminated. The dots
Ͷι ϐ ϐ
perimetry allows the practical assessment are one pixel in size and 580 asb or
of macular vision. It uses yet another
ϐ 2.75 log units above the background.
display technology, namely, Digital Light at higher resolution than conventional The dots are positioned randomly on a
Projection (DLP). This test is easily perimetry, which is clinically useful in gray background with a luminance of 50
portable and does not need a darkroom. glaucoma11. asb using a 640 × 480 pixel VGA video
display. The motion targets are circular
THE HEIDELBERG EDGE This allows us to investigate random dot cinematograms within which
ϐ 50% of the dots move centrifugally and
PERIMETER possible with conventional perimetry. 50% move in random directions. The
circular target itself is stationary, that is,
The new Heidelberg Edge Perimeter A recognised problem of high dots move within the target. Each trial
selectively tests retinal ganglion cells, spatial resolution perimetry is high is composed of 10 cinematogram frames
in this case, the magnocellular system. intratest variability, with a corresponding displayed in 174 msec. Each dot moves 2
The technology is based on the concept poor repeatability of the threshold pixels per frame giving a velocity of 11.76
ϐ
Ǧϐ ǡ
Ǧ measurements. deg/sec. Dots moving out of the circular
temporal-frequency stimulus undergoes window are wrapped back to the point
Ǧ ϐ
MOTION DETECTION PERIMETRY 180° from the dot exit position.
phantom contour illusion. The objective
is to recognize early glaucomatous Motion detection perimetry is a The stimuli are of 17 sizes with a
damage, and the instrument is similar method that measures a subject’s ability diameter step factor of 10.1 (1.259).
to perimeters with SWAP in that it can to detect a coherent shift in position The angle subtended by the stimuli
also perform SAP testing. With the HEP, of dots in a circular area against a ranges from 0.13° to 8.46°. The size of
ϐ
Ǧ
background of non-moving dots (Figure the stimulus varies from trial to trial,
an illusory edge due to differences in 5)12. and a 2/1 staircase procedure is used to
ϐ
bracket the threshold. The test, therefore,
Ǣ
Motion size threshold is the smallest continues until the smallest circle size
circular stimulus. An adaptive staircase detectable circular area in which the ǡ ϐ
thresholding algorithm makes testing subject can detect motion. Subjects test point, is bracketed by the staircase
times comparable to those with other respond by touching a computer screen procedure. Stimulus presentation is
algorithms. Further studies are needed to with a light pen where they detect motion randomized among the preselected test
understand the HEP’s ability to recognize stimuli. Their localization errors, as the
early loss.
HIGH SPATIAL RESOLUTION
AUTOMATED PERIMETRY
High spatial resolution perimetry is
performed using a Humphrey automated
www. dos-times.org 41
GLAUCOMA
loci. Fixation is monitored by the visual Test times for normals range from 12 to 3. Clement CI, Goldberg I, Healey PR, Graham
ϐ
Ǥ
ǡ ͶͶ 20 minutes. S. Humphrey matrix frequency doubling
locations are tested. Valid responses
ϐ
ϐ
ϐ
in open angle glaucoma. Br J Ophthalmol.
greater than 100 msec and less than 1 increased testing time. Motion detection ʹͲͲͻǢͻ͵ǣͷͺʹͷͺͺǤ
second and having a localization error perimetry appears to be more sensitive
of no more than 10° from the center of in detecting visual loss than conventional 4. Landers JA, Goldberg I, Graham SL. Detection
where the target is presented. The testing automated perimetry in various optic ϐ
ϐ ʹʹ
neuropathies including glaucoma and frequency-doubling perimetry and short-
by a lens holder attached to the monitor.
Ǥ ǯ
ϐ
wavelength automated perimetry. Arch
The monitor is on an adjustable-height has not yet been determined. Ǥ ʹͲͲ͵ǢͳʹͳǣͳͲͷͳͳͲǤ
table and is positioned so a subject is
comfortably seated looking slightly down. SUMMARY 5. McClure ME, Hart PM, Jackson AJ, Stevenson
The 17-inch diagonal monitor gives a 21° MR, Chakravarthy U. Macular degeneration:
ϐ ȋͶʹι Ͷʹι ȌǤ SAP although is the gold standard in do conventional measurements of impaired
the present day to detect presence and visual function equate with visual disability?
A trial is started by the subject holding progression of glaucoma, newer tests
ʹͲͲͲǢ ͺͶǣ ʹͶͶǦͷͲǤ
a light pen to the midpoint of the bottom are required to detect early ganglion
ϐ cell loss in glaucoma. Glaucoma being 6. Staurenghi, Giovanni, Andrea Giani, and
central cross. A stimulus is then displayed. an irreversible disease, early diagnosis Mario V. Cigada. “Retinal sensitivity by means
If the subject sees the stimulus, he or she and adequate assessment of disease of microperimetry in patients with different
lifts the pen signaling the response time. Ǣ drusen type.” Investigative Ophthalmology &
He or she then touches the pen to the this is possible only by developing new, Visual Science 55.13. 2014: 6117.
position on the video display where the cheap, patient and doctor friendly ways
center of the test target is perceived. An of perimetry other than the conventional 7. Hollander DA, Volpe NJ, Moster ML, Liu GT,
FTG Data Systems high resolution light methods. Balcer LJ, Judy KD, et al. Use of a portable
pen model FT-1000 is used. The reaction head mounted perimetry system to assess
time is calculated using a high resolution REFERENCES ϐǤ
Ǥ
timer function with 1-10 microsecond ʹͲͲͲǢͺͶǣͳͳͺͷȂͻͲǤ
accuracy. The subject receives feedback 1. Medeiros FA, Sample PA, Weinreb RN.
of the localization error at the end of each Corneal thickness measurements and 8. Numata, Takuya, et al. “Detectability of
trial. To help maintain attention, if the visual function abnormalities in ocular Visual Field Defects in Glaucoma With High-
subject comes within three pixels of the hypertensive patients. Am J Ophthamol. resolution Perimetry.” Journal of Glaucoma
target center, reinforcement is given as ʹͲͳ͵Ǣͳ͵ͷǣͳ͵ͳȂ͵Ǥ ʹͷǤͳͲǢ ʹͲͳǣ ͺͶǦͷ͵Ǥ
Ǧ ϐ Ǥ
2. Johnson CA, Sample PA, Zangwill LM, Vasile 9. Lin, S. R., et al. “Quantitative measurement of
ǡ ϐ
ǡ
ǡ ϐ
Structure and function evaluation (SAFE) ϐ Ǥdz
Ǥ
ϐ
ʹͶǤʹǢʹͲͳͷǣ ͳͲͲǦͳͲͶ
characteristics. Am J Ophthalmol, 2003, 135,
148-154. 10. Mulak M, Szumny D, Sieja-Bujewska A, Kubrak
M. Heidelberg edge perimeter employment
in glaucoma diagnosis--preliminary report.
Ǥ ʹͲͳʹǢʹͳǣͷǦͲǤ
11. Westcott MC1, McNaught AI, Crabb DP, Fitzke
FW, Hitchings RA.High spatial resolution
automated perimetry in glaucoma.Br J
Ǥ ͳͻͻǢͺͳǣͶͷʹǦͻǤ
12. Thurtell, Matthew, et al. “Eye Movement
Perimetry For Evaluation Of Visual Field Loss
In Patients With Glaucoma And Recovered
Optic Neuritis (S19. 004).” Neurology 82.10.
Supplement 2014: S19-004.
Financial Interest: ϔ
Ȁ
Ǥ
DOS Membership fee Revision
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revised to Rs. 5,600/-
with effect from September 10, 2016.
Felicitation
Hearty congratulation to Air Marshal Retd. (Dr.) M.S. Boparai on being conferred the Life
Time Achievement Award of NAMS for the year 2015
42 DOS TIMES - NOVEMBER-DECEMBER 2016
OCULAR ONCOLOGY
AN UPDATE ON OCULAR ONCOLOGY
Pukhraj Rishi, Vishvesh Agarwal
Ocular tumors are potentially fatal conditions ͳͲ Ȁ
Ƚʹ
ϐ
Ǥ Ǧ
1mIU/ml for 4-6 months.
advances in diagnostics and novel therapeutic
approaches have led to better outcomes with OSSN (OCULAR SURFACE SQUAMOUS NEOPLASIA)
reduction in the morbidity/mortality and OSSN is a disease covering a spectrum of lesions arising
improvement in globe salvage rates. This article
highlights recent advances in the diagnosis and management of from squamous cells of con-junctiva, cornea or both7. The gold
various ocular tumors. standard of treatment of OSSN has traditionally been sur-gical
excision followed by cryotherapy8. Other treatment modalities
CONJUNCTIVAL PAPILLOMA include radiotherapy, chemotherapy, photodynamic therapy
and antiviral medications. However, even after surgical excision,
Squamous cell papilloma is a benign tumor of squamous there are chances of recurrence necessitating deployment
epithelium caused by Human papilloma viruses serotypes 6 of other options such as radiotherapy or cryotherapy9. The
and 111. The conjunctival variant of squamous papilloma is chemotherapeutic agents include Mitomycin-C (MMC) and
also caused by HPV 6 & 112. It Ocular tumors are potentially fatal 5-Fluorouracil. MMC and 5FU
is a benign tumor but notorious have been used with some
for recurrence. It is generally
ϐ
success but the side effects
a sessile exophytic tumor in are troublesome10,11. Maskin
found most commonly at the morbidity. Re-cent advances ϐ
palpebral conjunctiva3. Various diagnostics and novel therapeutic ȽʹȾ
therapies exist for treatment approaches have led to better outcomes OSSN in 199412. Interferon are
of conjunctival papilloma with reduction in the morbidity/ part of the immune system’s
ranging from surgical excision response to microbes, tumors
to cryotherapy. The latest mortality and improvement in globe and other antigens. Interferon
ǦȽǤ salvage rates. This article highlights ȽʹȾ ȋ ǦȽʹȾȌ
ϐ form of interferon produced
treatment of recurrent laryngeal recent advances in the diagnosis and commercially. The mechanism
papillomatosis in 19814. Since
ǦȽʹȾ
then various forms of interferon, management of various ocular tumors OSSN is not exactly known.
oral as well as topical have been It may be due to its indirect
used to treat papillomas with good amount of success. The Ǧ
ϐ
Ǥ ǡ
ϐ
ʹͲͲ͵ ʹ
activates host cytotoxic effector cells and up-regulates the
ǦȽ5. Since immune response13. There are various pub-lished case series of
then a large number of conjunctival papillomas, both primary
ǦȽʹȾ14,15. Shields
ǡ ǦȽʹ6.
ǦȽʹȾ ȋη ͳͷ
Ǧ Ƚʹ η ͳͺͲι ǦȌ
of 72% while the rest 28% had partial resolution of the tumor16.
ǦȽʹȾ
(0.01%) every alternate day for 1 year to achieve a success rate of
97.75%17. Retinoic acid is also a known immunomodulator and
also causes reverse up-regulation of matrix metalloproteases,
ǦȽʹȾ18. The
ǦȽʹȾ
Ǧǡ
ϐ
ǡ ϐǦ
after injection.
Figure 1: 'ZVGTPCN RJQVQITCRJ YKVJ NKF GXGTUKQP TGXGCNU OWNVKRNG INTRA-ARTERIAL CHEMOTHERAPY IN
papillomatous lesions (arrow) affecting the palpebral conjunctiva over
the left upper lid (A) and left lower lid (B) at presentation. Complete RETINOBLASTOMA
regression of conjunctival lesions is seen following cryotherapy and
subconjuctival injection of interferon a2b (C and D). The management of retinoblastoma includes intravenous
chemoreduction (Vincristine, Carnoplatin and Etoposide),
transpupillary thermotherapy (TTT), cryotherapy, laser photo-
coagulation, plaque radiotherapy, external beam radiation
therapy, and enucleation. The treat-ment is tailored to each
www. dos-times.org 43
OCULAR ONCOLOGY
Figure 2: (QNNQYKPI GZEKUKQP HQT EQPLWEVKXCN USWCOQWU PGQRNCUKC FQPG GNUGYJGTG NGHV G[G TG XGCNU RGTUKUVKPI EQPIGUVKQP
NGHV CPF UWURKEKQWU
nodular lesion in the nasal palpebral con-junctiva. Lateral margin was positive for OSSN while deeper margins were negative. Three weeks after
subconjunctival injection of interferon and topical application, there is remarkable recovery.
Figure 3. Angiographic frame reveals micro- Figure 4: Retcam photo of left eye with group D retinoblastoma following three cycles of
catheter placed in the internal carotid artery KPVTCXGPQWU EJGOQVJGTCR[ TGXGCNU FKHHWUG XKVTGQWU UGGFU KP CNN HQWT SWCFTCPVU
# 6YQ OQPVJU
(horizontal arrow) with its tip at the ostium of after intravitreal melphalan (20 micrograms/0.05ml), there is near complete regression of vit-reous
the ophthalmic artery (vertical arrow). seeds (B).
individual case, including the treatment most often managed with enucleation i.e. age greater than 4 months
of metastatic disease, risks for second or external beam radiotherapy (EBRT). Short and long-term toxicities of
cancers, systemic status, laterality of the EBRT has known risks to the patient the current intravenous chemotherapy
disease, size and location of the tumours, including facial dys-morphism, cataract, regimen (Feldman) include transient
and estimated visual prognosis. Over the corneal dryness and decompensation, reduction in blood count, intermittent
past 15 years, intravenous chemotherapy radiation retinopathy, and papil-lopathy temporary fever, long-term toxicities
has been the most popular conservative and most importantly, Current indications of hearing loss, and reduction in
(eye-saving), method for retinoblastoma for Intra-arterial chemotherapy include renal function. Although intravenous
management because it is effective and potentially fatal second cancers. chemotherapy (IVC) has been the
safe. 1. Group B, C, D or E retinoblastoma in mainstay of treatment for group B, C
and D tumors, it has its own limita-tions
Intravenous chemotherapy has one or both eyes in terms of drug-resistance and limited
been successful in over 90% of cases 2. recurrent retinoblastoma following seed control. Newer treatment options
with mild to mod-erate retinoblastoma such as intravitreal and intraarterial
(Groups A, B and C), but was only partially previous failed standard therapies chemotherapy have contributed to
effective with 47% success for advanced 3. recurrent subretinal seeds or improved globe and life salvage in patients
retinoblastoma (Group D) and only 25% with retinoblastoma. Intra-arterial
for extensive retinoblastoma (Group E). recurrent vitreous seeds28.
The cases that failed chemotherapy were 4. ability to tolerate the procedure as
well as ease of doing the procedure
Shri Bhawan Mahavir Vitreoretinal Services, Sankara Nethralya, 18 College Road, Chennai-600006,Tamil Nadu, India
Dr. Pukhraj Rishi MS, DO Dr.Vishvesh Agarwal MS,
44 DOS TIMES - NOVEMBER-DECEMBER 2016
OCULAR ONCOLOGY
Figure 5: Left eye fundus photo of a 60 year old lady at presentation reveals diffuse vitritis with 2. Vitreous seeds recurrent after
placoid subretinal lesions at the macula and superotemporal periphery (A) consistent with previous therapy.
XKVTGQTGVKPCN N[ORJQOC #HVGT OQPVJN[ KPLGEVKQPU QH KPVTCXKVTGCN TKVWZKOCD
OI ON VJGTG KU The standard dose of melphalan
complete regression of lesions (B).
is 20-30 μg given every 4 weeks. The
ȋ Ȍ ϐ
hemorrhage, branch retinal artery requirement for further injections
for treatment of retinoblastoma by Reese obstruction, ophthalmic artery spasm depends on the response. Ghassemi et
in the year 1956 using a combination of with reperfusion, ophthalmic artery al recently published his experiences
alkylating agent triethylene melanamine obstruction, partial choroidal ischemia with the combination of intravitreal
via direct carotid artery access along and optic neuropathy29. melphalan (20μg/0.05ml) and topotecan
with radiation19. After that it was used (dose of 8 to 20 μg). The side effects
by several workers but it did not pick INTRAVITREAL CHEMOTHERAPY IN of intravitreal melphalan include
ϐ
iris atrophy, chorioretinal atrophy,
procedure and side effects of triethylene RETINOBLASTOMA vitreous haemorrhage and rarely
melamine20. It was not until the year 2004 retinal detachment35. The dose of 50 μg
when Kaneko published his successful Intravitreal drug therapy has the melphalan is toxic and causes phthisis
usage of intraarterial chemotherapy via advantage of delivering the drug at the bulbi and severe chorioretinal atrophy36.
femoral artery using balloon catheter site of the pathol-ogy while obviating the Side effects of intravitreal topotecan have
using the drug melphalan that the
Ǥ ϐ not yet been reported. It was earlier
technique began picking up21. Since then use of intravitreal chemotherapy (IvitC) theorised that intravitreal injection in
a number of authors have published dates back to 1960 when Thiotepa and retinoblastoma patients leads to tumor
several successful case series of IAC22,23,24. Methotrexate were used for treatment of spread but there are no such instances
Important among these were those Retinoblastoma30. This modality did not reported till date. On the contrary, it has
of Shields et al who obtained success gain much acclaim then. In 1987, Kaneko been proven experimentally that with
in all groups of IRCB (International pub-lished his results of successful in proper technique of intravitreal injection,
ϐ
Ȍ Ǥ vitro use of L-phenyl alanine mustard there is hardly any risk of spread of
best results were seen in groups B, C and in treatment of retinoblastoma in malignancy following intravitreal
D, although group E eyes did not do as comparison to methotrexate, doxorubicin, injection37.
well25. The technique has come a long way
ǡ
ǡ ͷǦϐ
since Kaneko et al described it. Instead name a few but not much could be made VITREORETINAL LYMPHOMA
of balloon catheter, microcatheters are out of it31. It was in the year 2003 that
used. The technique is monitored with Kaneko himself published the results TREATMENT WITH RITUXIMAB
ϐ
of his work that the therapy was taken
visualisation of the branches of internal seriously as the modality of choice in Vitreoretinal lymphoma (VRL) is
carotid artery. This technique is also treating cases of recurrent vitreous the most common type of intraocular
referred to as ‘superselective ophthalmic seedings and vitreous seedings refractory lymphoma caused by large B-cell. VRL
artery infusion (SSOAI)’. Catheterisation to intra-arterial and intravenous is a subtype of central nervous system
can also be achieved through middle chemotherapy32. It was however the (CNS) lymphoma. Traditionally, the
meningeal artery (MMA) access in pioneering work of Munier et al that gold standard for treating vitreoetinal
cases where ophthalmic artery arises deserves credit for the current status lymphoma has been radiotherapy
from MMA (anatomical variation) or of IvitC in treatment of Retinoblastoma. but with high incidence of ocular side
ϐ
Ǥ Various studies by different authors have effects radiation maculopathy, radiation
Persistence of retinal function despite found IVitC to be effective in treating retinopathy and radiation papillopathy
using IAC has also been reported in few vitreous seedings upto the rate of 90% because of the high dose of radiation
studies26,27. The main complications (80 to 100%)33,34. The main indication used for treating CNS Lymphoma.
include transient eye-lid edema, for intravitreal chemotherapy includes Also, the tumor invariably recurs after
blepharoptosis and forehead hyperemia. patients with the following: chemotherapy38. Use of chemotherapy
Long term complications include vitreous 1. Vitreous seeds non-responsive to also is not without side effects. The use of
intravitreal methotrexate (IVitMtx) in the
standard therapy, treatment of VRL was explored in 1997
ϐ
ͻͷΨ39. IVitMtx
also has side effects, the most frequent
being corneal epitheliopathy. Cases of
recurrence have also been reported40.
ϐ
of medicine led to the discovery of CD20
antigen on the surface of B lymphoma
cells in CNS lymphoma and later on in
vitreoretinal lymphoma41. It was then
theorised that antibodies directed
towards this antigen could be effective
in treating the primary tumor. Based
on this hypothesis, antibodies directed
towards CD20 antigen were explored
resulting in the discovery of a new drug,
www. dos-times.org 45
OCULAR ONCOLOGY
Ǥ ϐ ǤʹͲͳͶǢͶʹǣ͵ͳǦʹʹǤ GC, Ramasubramanian A, Rosenwasser R,
12. Maskin SL. Regression of limbal epithelial
for the treatment of CNS Lymphoma Shields JA. Intra-arterial Chemotherapy for
dysplasia with topical interferon [letter].
in 2007 by Rubenstein. In this sudy,
ͳͻͻͶǢͳͳʹǣͳͳͶͷȂǤ Retinoblastoma. Report No. 2, Treatment.
13. Baron S, Tyring SK, Fleischmann WR, Jr, et al.
the use of intraventricular rituximab The interferons. Mechanisms of action and
Ǥ ʹͲͳͳǢͳʹͻǣͳͶͲǦͳͷǤ
Ǥ
Ǥ ͳͻͻͳǢʹǣͳ͵ͷȂ
led to reduction in size of intraocular 83. 30. Ericson LA, Kalberg B, Rosengren BH. Trials
14. Karp CL, Moore JK, Rosa RH Jr. Treatment
tumor42. Its use in ocular tumors was of conjunctival and corneal intraepithelial of intravitreal injections of chemothera-
neoplasia with topical interferon alpha-2b.
supported by various authors43,44,45. The ʹͲͲͳǢͳͲͺǣͳͲͻ͵Ȃ ͺǤ peutic agents in rabbits. Acta Ophthalmol.
15. Shields CL, Kaliki S, Kim HJ, et al. Interferon
current indications for use of intravitreal for ocular surface squamous neoplasia in 81 ͳͻͶǢͶʹǣʹͳȂʹǤ
cases: outcomes based on the American Joint
rituximab in primary vitreoretinal
ϐ
Ǥ 31. Inomata M, Kaneko A. Chemosensitivity
ʹͲͳ͵Ǣ͵ʹǣʹͶͺȂͷǤ
lymphoma is isolated ocular disease 16. Kim HJ, Shields CL, Shah SU, Kaliki S, ϐ
Lally SE. Giant ocular surface squamous
(without systemic involvement). It can neoplasia managed with interferon alpha- reti-noblastoma cells in a human tumor
2b as immunotherapy or immunoreduction.
be a part of treatment armamentarium ǤʹͲͳʹǢͳͳͻǣͻ͵ͺȂͶͶǤ clonogenic assay. Jpn J Cancer Res.
17. Krilis M, Tsang H, Coroneo M. Treatment of
in bilateral disease in combination with conjunctival and corneal epithelial neoplasia ͳͻͺǢͺǣͺͷͺǦ
with retinoic acid and topical interferon alfa-
systemic chemotherapy or radiotherapy46. 2b: long-term follow-up.. Ophthalmology. 32. Kaneko A, Suzuki S. Eye-preservation
ʹͲͳʹǢͳͳͻǣͳͻͻǦ͵Ǥ
The main complications of intravitreal 18. Uchida G, Yoshimura K, Kitano Y, et treatment of retinoblastoma with vitreous
al. Tretinoin reverses upregulation of
rituximab are transient elevation of matrix metalloproteinase-13 in human ǦǤ
ǤʹͲͲ͵Ǣ͵͵ǣͲͳȂǤ
ϐǤ Ǥ
intraocular pressure, diffuse keratitic ʹͲͲ͵Ǣͳʹȋ Ȍǣ͵ͷȂ ͶʹǤ 33. Ghassemi F, Shields CL. Intravitreal
19. Hyman GA, Reese AB. Combination Therapy
precipitates (KPs) with anterior cells. of Retinoblastoma with Triethylene Melphalan for Refractory or Recurrent
Melamine and Radiotherapy. JAMA
In conclusion, these are some ͳͻͷǢͳʹǣͳ͵ͺǦ͵Ǥ Vitreous Seeding From Retinoblastoma. Arch
20. Reese AB, Hyman GA, Tapley ND, Forrest
ϐ
AW. The treatment of retinoblastoma by Ǥ ʹͲͳʹǢ ͳ͵ͲǣͳʹͺǦͳǤ
X-ray and triethylene melamine. AMA Arch
oncology that enhance the treatment Ǥ ͳͻͷͺǢ ͲǣͺͻǦͻͲǤ 34. Kivela T, Paloheimo M, Eskelin T. Intravitreal
21. Yamane T, Kaneko M, Mohri A. The technique
Ǧ
Ǥԙ of ophthalmic artery infusion therapy Methotrexate for Retinoblastoma. Oph-
for introcular retinoblastoma. Int J. Clin
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22. Shields CL, Manjandavida FP, Lally SE,
1. Elango KJ, Suresh A, Erode EM, Subhadradevi Pieretti G, Arepalli SA. Intra-arterial 35. Ghassemi F, Shields CL, Ghadimi H,
L, Ravindran HK, Iyer SK, Iyer SK, Kuriakose Chemotherapy for Retinoblastoma in 70
MA. Role of human papilloma virus in oral Ǥ Ǥ ʹͲͳͶǢͳʹͳǣͳͶͷ͵ȂͲǤ Khodabandeh A, Roohipoor R. Combined
tongue squamous cell carcinoma. Asian Pac 23. Abramson DH, Dunkel IJ, Brodie SE,
Ǥ ʹͲͳͳǢͳʹǣͺͺͻǦͻǤ Kim JW, Gobin YP. A phase I/II study of in-travitreal melphalan and topotecan for
direct intraarterial (ophthalmic artery)
2. Sjö NC, Heegaard S, Prause JU, von Buchwald chemotherapy with melphalan for refractory or recurrent vitreous seeding
C, Lindeberg H. Human papillomavirus in intraocular retinoblastoma initial results.
conjunctival papilloma. Br J Ophthalmol Ǥ ʹͲͲͺǢ ͳͳͷǣͳ͵ͻͺǦͶͲͶǤ from reti-noblastoma. JAMA Ophthalmol.
ʹͲͲͳǢ ͺͷǣͺͷȂͺǤ 24. Klufas MA, Gobin YP, Marr B, Brodie SE,
Dunkel IJ, Abramson DH. Intra-arterial ʹͲͳͶǢͳ͵ʹǣͻ͵ǦͶͳǤ
3. Sjö N, Heegaard S and Prause JU. Conjunctival chemotherapy as a treatment for intraocular
papilloma A histopathologically based retinoblastoma: alternatives to direct 36. Smith SJ, Smith BD, Mohney BG. Ocular
retrospective study. Acta Ophthalmol Scand ophthalmic artery catheterization. Am J
2000:78: 663–66. Ǥ ʹͲͳʹǢ͵͵ǣͳͲͺǦͳͶǤ side effects following intravitreal injection
25. Murphee LA. Intraocular retinoblastoma:
4. Kaliki S, Arepalli S, Shields CL, Klein K, Sun
ϐ
Ǥ therapy for retinoblastoma: a systematic
H, Hysenj E, et al. Conjunctival Papilloma Ǥ ʹͲͲͷǢͳͺǣͶͳǦͷ͵Ǥ
Features and Outcomes Based on Age at 26. Brodie SE, Pierre Gobin Y, Dunkel IJ, Kim Ǥ
Ǥ ʹͲͳͶǢͻͺǣʹͻʹǦǤ
Initial Examination. JAMA Ophthalmol JW, Abramson DH. Persistence of retinal
ʹͲͳ͵Ǣͳ͵ͳǣͷͺͷǦͻ͵Ǥ function after selective ophthalmic artery 37. Smith JS, Smith BD. Evaluating the risk
chemotherapy infusion for retinoblastoma.
5. de Keizer RJW, de Wolff-Rouendaal D. Topical
ǤʹͲͲͻǢͳͳͻǣͳ͵ȂʹʹǤ of extraocular tumour spread following
Ƚ Ǧ
27. Francis JH, Abramson DH, Gobin YP,
papilloma. Acta Ophthalmol Scand 2003: Marr BP, Dunkel IJ, Riedel ER, Brodie SE. in-travitreal injection therapy for
81:193–96 Electroretinogram Monitoring of Dose-
Dependent Toxicity after Ophthalmic Artery retinoblastoma: a systematic review. Br J
6. Shields CL and Shields JA. Conjunctival Chemosurgery in Retinoblastoma Eyes: Six
tumors in children. Curr Opin Ophthalmol Year Review. Ǧ ʹͲͳ͵Ǣͻǣͳʹ͵ͳǦ͵Ǥ
ʹͲͲǢͳͺǣ͵ͷͳȂ͵ͲǤ 28. Shields CL, Lally SE, Leahey AM, Jabbour PM,
Caywood EH, Schwendeman R, Shields J A. 38. Pe’er J, Hochberg FH, Foster CS. Clinical
7. Lee GA, Hirst LW. Ocular surface squamous Targeted retinoblastoma management: when
Ǥ ͳͻͻͷǢ͵ͻǣͶʹͻȂ to use intravenous, intra-arterial, periocular, Review: Treatment of Vitreoretinal Lym-
50. and intravitreal chemotherapy. Current
Ǥ ʹͲͳͶǢʹͷǣ͵ͶȂͺͷǤ Ǥ
Ƭ ϐǤ
ͺǤ ǡ ϐ Ǥ ʹͻǤ ǡ
ǡ
ǡ
ϐ
intraepithelial epitheliomas and squamous ʹͲͲͻǢͳǣʹͻͻȂ͵ͲǤ
cell carcinoma of the limbus. Trans Am
Ǥ ͳͻͺͲǢͺǣʹͻͲȂ͵ͲͲǤ 39. Fishburne BC, Wilson DJ, Rosenbaum JT,
9. Tabin G, Levin S, Snibson G, et al. Late Neuwelt EA. Intravitreal Methotrexate as
recurrences and the necessity for
long-term follow-up in corneal and an Adjunctive Treatment of Intraocular
conjunctival intraepithelial neoplasia.
ǤͳͻͻǢ ͳͲͶǣͶͺͷȂͻʹǤ Lymphoma. Arch Ophthalmol.
10. Ballalai PL, Erwenne CM, Martins MC, ͳͻͻǢͳͳͷǣͳͳͷʹǦͷǤ
Lowen MS, Barros JN. Long-Term Results
of Topical Mitomycin C 0.02% for Primary 40. Frenkel S, Hendler K, Siegal T, Shalom
and Recurrent Conjunctival-Corneal
Intraepithelial Neoplasia. Ophthal Plast E, Pe’er J. Intravitreal methotrexate for
ʹͲͲͻǢʹͷǣʹͻȂͻͻǤ
treating vitreoretinal lymphoma: 10 years of
11. Bahrami B, Grenwell T Muecke J. Long-
term outcomes after adjunctive topical experience.Br J Ophthalmol 2008.92:383-8.
ͷǦϐ
treatment of surgically excised, localized 41. Raparia K, Chang CC, Chévez-Barrios P.
ocular surface squamous neoplasia. Clin
Intraocular lymphoma: diagnostic approach
ϐ
vitrectomy specimens. Arch Pathol Lab Med.
ʹͲͲͻǢͳ͵͵ǣͳʹ͵͵ǦǤ
42. Rubenstein JL, Fridlyand J, Abrey L, et al.
Phase I study of intraventricular admin-
istration of rituximab in patients with
recurrent CNS and intraocular lymphoma. J
Ǧ
ǤʹͲͲǢʹͷǣͳ͵ͷͲȂǤ
43. Kitzmann AS, Pulido JS, Mohney BG, Baratz
KH, Grube, Marler RJ. (Lond). Intraocular use
Ǥ Ǥ ʹͲͲǢʹͳǣͳͷʹͶǦǤ
ͶͶǤ ǡ ǡ Ǥ ϐ
and complications of intravitreal rituximab
injection for treating primary vitreoretinal
Ǥ
ʹͲͳʹǢͳǣͳǦͳͳǤ
45. Levasseur SD, Wittenberg LA, White VA.
Vitreoretinal lymphoma: a 20-year review
of incidence, clinical and cytologic features,
treatment, and outcomes. JAMA Ophthalmol-
Ǥ ʹͲͳ͵Ǣͳ͵ͳǣͷͲȂͷǤ
46. Chan CC, Rubenstein JL, Coupland SE,
Davis JL, Harbour JW, Johnston PB. Primary
vitreoretinal lymphoma: a report from an
International Primary Central Nervous
System Lymphoma Collaborative Group
Ǥ
Ǥ ʹͲͳͳǢͳǣͳͷͺͻǦͻͻǤ
Financial Interest: ϔ
Ȁ
Ǥ
46 DOS TIMES - NOVEMBER-DECEMBER 2016
OCULAR MICROBIOLOGY
PRIMARY MICROSCOPY AS A POINT OF
CARE TEST IN OPHTHALMOLOGY
Nishat Hussain Ahmed, Gita Satapathy
Primary microscopy is done directly from the clinical specimens. Like other infective
ϐ
Ǥ
idea about the type and load of pathogenic micro-organism, as well as a picture of
ϐ
Ǥ
commonly used primary microscopy techniques can go a long way in managing ocular
infections.
M
ϐ
has always been an important pillar in after Danish bacteriologist Hans Christian Gram, who developed
diagnosing infectious diseases. This holds the technique.
true even in ophthalmic infections. The
microscopy which is done directly from Method
the clinical specimen is called primary
Ǣ
Ȃ
It involves the use of applying two contrasting coloured
on the growth obtained upon culture. Primary microscopy ϐ
Ǥ
has explicit role in diagnosing ocular infections. In fact, given First, the primary dye, crystal violet or gentian violet is applied
the requirement of patient side preparation of slides due to for one minute which is then drained and washed. Next, Gram’s
minute sample size, knowledge of few simple microscopic iodine is added on to the smear and kept for one minute
techniques and their correct interpretation and application following which it is drained and washed. Decolorization is
ϐ
done using acetone (2-3 seconds) or ethanol (30-60 seconds)
infections. and thorough washing of the smear is done. At the end, counter-
Being familiar with the important role of bacteria and fungi stain safranin is applied for 30 seconds and washed. The smear
in ocular infections, understanding the most popular primary is allowed to air dry and is observed under oil immersion
objective of light microscope.
microscopy techniques for these organisms can be exceedingly
valuable in pointing towards possible pathogen causing the
infection.
GRAM STAINING
Gram staining is a differential staining technique named
Figure-1: Pus cells and gram positive cocci in pairs, each pair is Figure-2: Pus cells and gram positive cocci in clusters, (arrows);
surrounded by a clear halo suggestive of capsule (arrows); probably suggestive of Staphylococcal infection Photo source: http://www.
Streptococcus pneumoniae Photo source: http://www.cdc.gov ETCO EQO ƀCUJECTFU
www. dos-times.org 47
OCULAR MICROBIOLOGY
Principle Interpretation Application
Gram positive and gram negative The gram positive bacteria appear Knowledge of the possible
bacteria differ in the structure of their Ǣ etiologies in different clinical scenarios
cell walls and membranes, and in gram negative bacteria appear pink of ocular infections, augmented with the
the composition of their protoplasm. due to counter-stain. Other than the interpretation of a properly done and
Thicker peptidoglycan layer and acidic gram’s reaction, things which need to be observed gram stained smear can help
protoplasm of the gram positive bacteria observed in the smear include presence to identify the pathogenic bacteria. Some
allows them to retain the basic primary ϐ
ǡ examples are given below:
dye against decolorization, whereas arrangement of the bacteria, uniformity 1. Primary gram stained smear
thinner peptidoglycan layer and labile of staining and hint of capsule or spores.
outer membrane in gram negative ǡ Ǣ showing pus cells along with gram
bacteria permits decolorization. The
ϐ positive cocci in pairs, and each
decolorized gram negative bacteria then with the characteristic morphology of pair surrounded by a clear halo
take up the counter-stain. yeast cells and hyphae.
ȋ ǦͳȌǢ
the probable etiological agent is
Streptococcus pneumoniae.
Figure-3: Pus cells and gram negative bacillii Photo source: Sharma et Figure-4: Pus cells and gram negative cocci in pairs, both intracellular
al, JCDR. 2014:8(5):OD03 - OD05 CPF GZVTCEGNNWNCT
CTTQYU UWIIGUVKXG QH Neisseria gonrrhoeae
infection. Photo courtesy: Dr. S Sood and Dr. A Prabhu, Microbiology
Department, AIIMS, New Delhi
Figure-5: Fungal hyphae seen in 10% KOH mount. Photo source: Figure-6: #UGRVCVG HWPICN J[RJCG UGGP KP -1* ECNEQƀQWT OQWPV
Ocular Microbiology, Dr. RP Centre, AIIMS, New Delhi 2JQVQ EQWTVGU[ &T + ZGUU CPF &T ) 5KPIJ /[EQNQI[ /KETQDKQNQI[
Department, AIIMS, New Delhi
Ocular Microbiology Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences,All India Institute of Medical Sciences, New Delhi, India
Dr. Nishat Hussain Ahmed Dr. Gita Satapathy
Assistant Professor of Microbiology Professor of Microbiology
48 DOS TIMES - NOVEMBER-DECEMBER 2016
OCULAR MICROBIOLOGY
Figure-7: 5GRVCVG HWPICN J[RJCG UGGP KP -1* ECNEQƀQWT OQWPV Figure-8: Candida pseudo-hyphae (arrows-1) and yeast cells (arrow-2)
2JQVQ EQWTVGU[ &T + ZGUU CPF &T ) 5KPIJ /[EQNQI[ /KETQDKQNQI[ UGGP KP -1* ECNEQƀQWT OQWPV 2JQVQ EQWTVGU[ &T + ZGUU CPF &T )
Department, AIIMS, New Delhi Singh, Mycology, Microbiology Department, AIIMS, New Delhi
2. Gram stained smear showing pus A more rapid and more sensitive with characteristic morphology
cells and gram positive cocci in method to detect fungal elements is to (Figure-5).
clusters (Figure-2). The case is of ͳͲΨ ͲǤͳΨ
ϐ
Staphylococcal infection. white stain for making the mounts. Care should be taken to differentiate
ϐ ϐ
fungal hyphae from artefacts such as
3. Figure -3 shows pus cells and gram which binds to the chitin in the cell walls
ϐ
Ǥ
negative bacilli. of the fungi. This method requires a
ϐ
ϐ ϐ To enhance the contrast, a drop of
4. Figure-4 shows pus cells and to give an excitation with ultraviolet light lacto-phenol-cotton-blue can be allowed
gram negative intracellular and below 400 nm wavelength. to permeate through the edge of the cover
extracellular diplococci (cocci in slip which will stain the fungal wall light
pairs) in a gram stained smear Principle blue.
suggesting infection of Neisseria
gonorrhoeae. KOH digests the animal cells, leaving
ͲǤͳΨ
ϐ
behind the fungal elements intact. To white stain, fungal elements will show
POTASSIUM HYDROXIDE (KOH) enhance the digestion of tough tissues chalk-white or brilliant apple green
MOUNTS (e.g. corneal or lid scrapings), one or ϐ
ǡ ϐ
more of the following can be done: used. Figures 6, 7 and 8 show aseptate
Potassium hydroxide mounts are 1. Increasing the time of incubation (30 fungal hyphae, septate fungal hyphae, and
used for detection of fungal elements in Candida yeast cells and pseudohyphae
patients’ specimens. minutes to 2 hours).
ϐ Ǥ
2. Increasing the temperature of
Method DISPOSAL OF SLIDES
incubation (37°C to 60°C).
The specimen is placed on a clean 3. Increasing the concentration of KOH As the slides contain infectious
glass slide and teased. 1-2 drops of 10% specimen, after observation they should
KOH are placed on the specimen. A cover (20% to 40%). be disposed at the site in puncture proof
slip is applied on top, taking care not and tamper proof container.
to introduce air bubbles. The mount is Interpretation
incubated at room temperature for a few
minutes and observed under 10X and 40X Fungal elements can be appreciated
objectives of light microscope. ϐǡ
ǡ
aseptate hyphae, yeast cells or conidia
Financial Interest: ϔ
Ȁ
Ǥ
www. dos-times.org 49
MONTHLY MEETING KORNER
NASAL ENDOSCOPY AND LACRIMAL SYSTEM:WHAT LIES
BEYOND ROUTINE DCR!
REPORT OF A RARE SAC IN ETHMOID SINUS SYNDROME
Dr. Saurabh Kamal MS, FLVPEI ϐ ȋ
Eye HUB (Faridabad) 1E). There were intrasac synechiae and granuloma near
M.M. Eyetech Institute (New Delhi) common canaliculus which were released and excised. MMC
0.04% was applied for 3 minutes and Circumostial injection of
A52 years-old male presented with persistent MMC was given as described earlier by author1. Bicanalicular
watering in right eye since 3 years. He underwent silicone intubation was done. At the end of the surgery, sac was
external DCR (dacryocystorhinostomy) twice, opened completely in book like fashion with sac-nasal mucosa
ϐ ʹ
approximation (Figure 1F). Postoperative systemic antibiotics
was 6 months back, both time operated and analgesics, topical antibiotic-steroid eyedrop in tapered
elsewhere. Anterior and posterior segments dose, and nasal decongestants were given for 3 weeks.
were normal, except for right eye pseudophakia and left eye
ϐ
Ǥ
Nasal endoscopy and tube removal was done at 4 weeks.
(ROPLAS) was negative. Irrigation showed regurgitation of Ostium was large, well healed, situated in the anterior ethmoidal
ϐ
air cells, FEDT (functional endoscopic dye test) was positive,
stop at 14 mm from the punctum. Nasal endoscopy showed internal common opening (ICO) was dynamic, and there were
ϐ
no synechiae and granulation tissue (Figure 2). Patient was
site of ostium (Figure 1A). There was mild septal deviation asymptomatic at the end of 3 months follow up and was taken
and middle turbinate was normal. Patient was undertaken for for left eye cataract surgery successfully.
Endoscopic revision DCR with Mitomycin-C (MMC) and silicone
intubation under local anesthesia. Figure 1: Panel of photographs demonstrating the intraoperative
UVGRU CPF ſPFKPIU (A): Nasal Endoscopy view of right nasal cavity
Endoscopic revision DCR offers showing lateral wall of nose on left side and nasal septum on right
advantage of avoiding cutaneous UKFG #TTQY UJQYKPI VJG OQWPF QH EKECVTKZ CV RTGXKQWU QUVGQVQO[ UKVG
incision (particularly if previous (B): Shows new abnormal bone formation (arrow) after nasal mucosal
external scar is evident), recognition/ ƀCR GNGXCVKQP (C): Dotted circle showing the boundaries of anterior
correction of intranasal abnormality, ethmoid sinus and probe lying within it indicating sac in ethmoid sinus
achieving mucosal approximation, easy syndrome. (D): Position of lacrimal sac indicated by star, lying within
enlargement of ostium and managing the ethmoid sinus. (E): Lacrimal sac opened in a book like fashion, white
sac pathologies. Endoscopic approach CTTQY KPFKECVKPI CPVGTKQT UCE ƀCR CPF [GNNQY CTTQY KPFKECVKPI RQUVGTKQT
allow recognition of factors responsible ƀCR (F): 8KGY CV VJG GPF QH UWTIGT[ UJQYKPI UCE ƀCRU RQUKVKQPGF CRCTV
for failure and thus their appropriate KP CRRTQZKOCVKQP YKVJ PCUCN OWEQUC CPF UKNKEQPG VWDG KP UKVW
PQVG
management because of better minimal bleeding during surgery).
visualization
www. dos-times.org 51
Nasal mucosal incision was given to expose the underlying
cicatrix which consisted of new bone formation (osteo-
Ȍ ȋ ͳ ȌǤ Ǧ ϐ
bone punch. Probe through upper punctum showed slight
movement over lateral nasal wall above the cicatrix i.e. previous
osteotomy site. Anterior ethmoidal and agger nasi cells were
opened up in an attempt to expose and locate the remnant
lacrimal sac (Figure 1C). Osteotomy was enlarged superiorly
and anteriorly. Lacrimal sac was noted to be entirely within the
anterior ethmoid air cells (Figure 1D). Sac was opened with
MONTHLY MEETING KORNER
Ǥǡ
ϐ
and managed with endoscopic approach
only. Endoscopic approach, therefore
offer many advantages in revision and/
or even primary cases compared with
external approach.
REFERENCES
1. Kamal S, Ali MJ, Naik MN. Circumostial
injection of mitomycin C (COS-
MMC) in external and endoscopic
ǣ ϐ
ǡ
ϐǡ
Ǥ
ʹͲͳͶǢ͵ͲǣͳͺǦͻͲǤ
2. Welham RA, and Wulc AE. Management
of unsuccessful lacrimal surgery. Br J
ͳͻͺǢͳǣͳͷʹȂǤ
3. Rose GE, and Walland MJ. Factors
affecting the success rate of open
lacrimal surgery. Br J Ophthalmol
ͳͻͻͶǢͺǣͺͺͺȂͻͳǤ
4. Figueira E, Al Abbadi Z, Malhotra
R, Wilcsek G, Selva D. Frequency of
Figure 2: 2JQVQITCRJ UJQYKPI VJG YGNN JGCNGF NCTIG QUVKWO YKVJ ƀWQTGUEGKP F[G VJTQWIJ KPVGTPCN simultaneous nasal procedures in
common opening (arrow), indicating functional success and open anterior ethmoid air cells (two
white stars). endoscopic dacryocystorhinostomy.
Ophthal Plast Reconstr Surg
ʹͲͳͶǢ͵ͲǣͶͲǦ͵Ǥ
5. Fayet B, Katowitz WR, Racy E,
DISCUSSION ǡ ϐ
ǡ
Ruban JM, Katowitz JA. Endoscopic
synechiae and granulation with in the
There have been studies describing sac. Sac in ethmoid sinus is a rare entity, dacryocystorhinostomy: the keys
the role of revision endoscopic DCR with not well described in literature. Only
success ranging from 76.5%-94%2-10. very recently, largest series published by to surgical success. Ophthal Plast
Either of the two, external or endoscopic Ali MJ consisted of 15 such patients, and
approach can be performed for failed only 2 were diagnosed during endoscopic
ʹͲͳͶǢ͵ͲǣͻǦͳǤ
cases. Endoscopic revision DCR offers revision surgery11. Diagnosis is based
advantage of avoiding cutaneous incision ϐ
6. Kamal S, Ali MJ, Naik MN. Circumostial
(particularly if previous external scar sac lying completely with in the ethmoid
is evident), recognition/correction of sinus. Certain preoperative clues are deep injection of mitomycin C (COS-
intranasal abnormality, achieving mucosal set eyes, steep nasal bridge and posterior
approximation, easy enlargement of insertion of medial canthal tendon. These MMC) in external and endoscopic
ostium and managing sac pathologies3,4. cases need careful opening of ethmoid
Endoscopic approach allow recognition sinus avoiding anterior ethmoidal artery
ǣ ϐ
ǡ
of factors responsible for failure and thus and orbital injury, like doing mini FESS
their appropriate management because (functional endoscopic sinus surgery) ϐǡ
Ǥ
of better visualization7,8,9. to expose the lacrimal sac and achieve
successful outcome with DCR. This is best
ʹͲͳͶǢ͵ͲǣͳͺǦͻͲǤ
For example, in present case following possible with endoscopic approach.
multiple factors as causes of failure 7. Singh M, Ali MJ, Naik MN. Long-Term
ϐ There may be other factors
the endoscopic approach. These were: for failures such as large agger nasi Outcomes of Circumostial Injection
osteoneogenesis (new bone formation), cell, turbinate adhesion to ostium,
improper located osteotomy (inferior nasal synechiae, paradoxical middle of Mitomycin C (COS-MMC) in
Ȍǡ ϐ
turbinate, deviated nasal septum, ostium
superior and anterior osteotomy, granulomas, high internal common Dacryocystorhinostomy. Ophthal Plast
failure to identify sac in ethmoid sinus
ʹͲͳͷǢ͵ͳǣͶʹ͵ǦͶǤ
8. Metson R. The endoscopic approach
for revision dacryocystorhinostomy.
ͳͻͻͲǢͳʹǣͳ͵ͶͶǦǤ
9. Choussy O, Retout A, Marie JP, Cozlean
A, Dehesdin D. Endoscopic revision
of external dacryocystorhinostomy
Ǥ ʹͲͳͲǢͶͺǣͳͲͶǦǤ
10. Demarco R, Strose A, Araújo M,
Valera FC, Moribe I, Anselmo-Lima
WT. Endoscopic revision of external
dacryocystorhinostomy. Otolaryngol
ʹͲͲǢͳ͵ǣͶͻǦͻǤ
11. Ali MJ, Singh S, Naik MN. Entire
lacrimal sac within the ethmoid
sinus:outcomes of powered endoscopic
dacryocystorhinostomy. Clin
ʹͲͳǢͳͲǣͳͳͻͻǦʹͲ͵Ǥ
Financial Interest: ϔ
Ȁ
Ǥ
52 DOS TIMES - NOVEMBER-DECEMBER 2016
SNAPSHOT
OCULAR TOXOPLASMOSIS
Shrinkhal, M.K. Singh
A 16 year female presented with chief complaint of sudden painless non-progressive
diminution of vision in right eye for last 3 days. Detailed examination revealed inactive
ocular toxoplasmosis. Poor visual prognosis was explained and kept on follow-up
A16 year female presented to our department
with chief complaint of headache, sudden
painless non-progressive diminution of vision
in right eye for last 3 days. She was apparently
well 3 days back, and then incidentally she
closed her left eye and noticed diminution of
vision in right eye. Her visual acuity was 6/60p in right eye on
ǯ
Ǣ
eye visual acuity was 6/6. Intraocular pressure was 18 mm of
Hg by Applanation tonometry in both the eyes. There was no
history of trauma, fever, headache, any drug intake before she
noticed her decreased vision in right eye. She had normal birth
at term.
On examination, Anterior segment was within normal
limits in both eyes. Pupillary reaction showed RAPD Grade
2 in right eye, left eye was normally reacting both direct and
consensual. Media were clear in both eyes. Fundus examination
of right eye revealed tilted optic disc. Macular area had a large
retinochoroidal atrophic patch (Figure 1) area of about 3 disc
diameter horizontally and 3 disc diameter vertically. The lesion Figure 2: Left eye coloured fundus photograph: Several peripapillary
had pigmented sharp boundary with no vitritis. The lesion’s healed retinochoroidal patches nasally.
base was about 6 diopters (2mm) deep from its margin. On
ͺ ǡ
ϐǤ ͵
Figure 1: Right eye coloured fundus photograph: Tilted optic disc. Figure 3: Spectral domain Optical coherence tomography of right eye
Macular with a large retinochoroidal atrophic patch area of about 3 *& NKPG TCKUVGT OCEWNCT CTGC # NCTIG GZECXCVKQP CV VJG OCEWNCT CTGC
disc diameter horizontally and 3 disc diameter vertically. The lesion of 1640 micron depth.
has pigmented sharp boundary with no vitritis.
dimensional 78D examination revealed an excavated lesion. No
other active or healed lesion was found elsewhere on indirect
ophthalmoscopy.
Left eye also showed peripapillary healed retinochoroidal
patches nasally (Figure 2). Peripheral fundus was normal.
Spectral domain Optical coherence tomography of right
eye was done. HD 5 line raister macular area showed a large
excavation at the macular area of 1640 micron depth (Figure 3).
www. dos-times.org 53
SNAPSHOT
Figure 4: Spectral domain Optical coherence Figure 5: Spectral domain Optical coherence tomography of right eye 3 Dimensional visualization
tomography of right eye Macular cube QH 4KIJV G[G OCEWNCT CTGC 2TQITGUUKXG GZECXCVKQP DQVJ CPVGTQ RQUVGTKQTN[ CPF KP TGVKPCN RNCPG
analysis (512*128): Severely depressed cube
XQNWOG
OO USWCTG CPF CXGTCIG EWDG or both eyes, and the lesions can be solitary,
thickness(163 micron)which comes under
<1% of normal population. multiple or satellite to a pigmented
Macular cube analysis (512*128) retinal scar. The retina is the primary site
showed severely depressed cube volume
(5.9 mm square)and average cube of T. gondii infection in the eye but the
thickness(163 micron)which comes
under <1% of normal population (Figure choroid, vitreous and anterior chamber
4).
ϐǤ
3 Dimensional visualization of the
macular area showed a progressive is retinochoroiditis i.e. the choroid is
excavation both anteroposteriorly and in
retinal plane (Figure 5). secondarily affected, meaning choroidal
Left eye HD 5 line raister macular lesions do not occur in the absence of
area (Figure 6) was within normal limits.
retinal infection. Active lesions present as Figure 6: Spectral domain Optical coherence
Provisional diagnosis of Congenital tomography of Left eye HD 5 line raister
toxoplasmosis with characteristic grey-white focus of retinal necrosis with macular area: within normal limits.
inactive wagon wheel appearance at
right eye macula was made. Left eye also adjacent choroiditis, vasculitis (Kyreleis
Dz
dz
ϐ
had inactive retinochoroidal lesions. therapy for ocular toxoplasmosis and
On serological examination, Ig G titre arteriolitis), hemorrhage and associated is the most common drug combination
ϐ
used.Patients with active toxoplasmosis
positive. No treatment was prescribed vitritis. Borders of the active lesion are may also be treated with trimethoprim-
for ocular toxoplasmosis as it was an sulfamethoxazole with or without
old healed scar. A regular follow up Ǥ ϐ
adjunctive clindamycin and prednisone
eye examination every six months was for four to six weeks.
recommended. the periphery towards the center of the
In patients with frequent
DISCUSSION lesion, with variable pigmentary changes. recurrences, long-term intermittent
treatment with trimethoprim (160 mg)/
Ocular toxoplasmosis is the most Healed lesion will have sharp boundary sulfamethoxazole (800 mg), one tablet
common cause of posterior uveitis 3 times a week reduced the rate of
worldwide. It is caused by the protozoa with no associated vitritis. The mother recurrent toxoplasmic retinochoroiditis
parasite Toxoplasma gondii, and can be from 23.8% to 6.6%4.
acquired congenitally or by ingesting can transmit toxoplasmosis to the fetus
uncooked meat infected with cysts or REFERENCES
vegetables and water contaminated if infected by T. gondii during pregnancy
by oocysts shed by cats1.It is the most 1. Silveira, C., et al., Acquired toxoplasmic infection
common cause of infectious intraocular or a few months before conception2. as the cause of toxoplasmic retinochoroiditis in
ϐ ȋȌǤ Ǥ
ǡ ͳͻͺͺǢͳͲǣ Ǥ ͵ʹǦͶǤ
typically affects the posterior pole of one The infection can result in visual and
2. Montoya JG and Liesenfeld O, Toxoplasmosis.
hearing loss, mental and psychomotor The Lancet., 2004. 363: p. 1965-76.
retardation, seizures, hematological 3. Montoya JG and Remington JS, Management of
Toxoplasma gondii infection during pregnancy.
abnormalities, hepatosplenomegaly, Clin Infect Dis., 2008. 47: p. 554-66.
Ǥ
ϐ 4. Silveira C, B.R.J., Muccioli C, Holland GN, Victora
CG, Horta BL, Yu F, Nussenblatt RB., The effect
trimester of gestation has a lower chance of long-term intermittent trimethoprim/
sulfamethoxazole treatment on recurrences of
of congenital transmission, but more toxoplasmic retinochoroiditis. Am J Ophthalmol.,
2002. 134: p. 41-46.
severe consequences for the fetus when
compared to the third3.
ThediagnosisofOculartoxoplasmosis
is mainly clinical. Serological diagnosis
can be done by IgG antibody titre
demonstration. Pathological diagnosis of
ocular toxoplasmosis can be established
by identifying the cysts in biopsies stained
with hematoxylin and eosin (H&E).
The use of pyrimethamine,
sulfadiazine, and corticosteroids is
Department of Ophthalmology, Institute of Medical Sciences, Banaras Hindu University,Varanasi
Dr. Shrinkhal MBBS Dr. M.K. Singh MS
Financial Interest: ϔ
Ȁ
Ǥ
54 DOS TIMES - NOVEMBER-DECEMBER 2016
SNAPSHOT
CONCURRENT BILATERAL NECROTIZING VIRAL
STROMAL KERATITIS
Abhishek Dave, Hafsa Bashir, Arpan Gandhi
56 year old male presented to our cornea clinic with chief complaints of blurring of
vision accompanied with pain and redness in both the eyes for past 25 days. There
was no history of trauma or any other immediate inciting factor before this episode
started. The patient gave no history of fever, joint pain, diabetes mellitus or any other
Aϐ
Ǥ close to face in left eye. On slit lamp examination he had
56 year old male presented to our cornea clinic bilateral lid edema with circumcorneal congestion. Right
with chief complaints of blurring of vision eye had a central epithelial defect measuring 3mmx2mm
accompanied with pain and redness in both the ϐ ͳ Ǥ
eyes for past 25 days. There was no history of central corneal scar with an epithelial defect superior to it
trauma or any other immediate inciting factor
before this episode started. The patient gave ͷͶ ϐ
Ͷ
no history of fever, joint pain, diabetes mellitus or any other mm hypopyon. There was associated corneal thinning (Figure
ϐ
Ǥ ǡ 1A & 1B). Corneal sensations were reduced bilaterally. Both the
gave history of recurrent redness in left eye for past 25 years eyes showed a clear lens. Right eye had a good fundal glow, but
which lasted for a few days and used to be self-limiting. The retinal details could not be seen. Left eye fundal glow could not
patient also gave history of opacity in the left eye for past many be seen.
years because of which the vision in left eye was blurred as A detailed workup as for any corneal ulcer was done. Both
compared to the right eye. For past 10 days he was on treatment eye naso-lacrimal systems were patent. Corneal scrapping was
ϐ
ͲǤͷΨ ͳ ǡ
ͷΨ sent for a detailed microbiological evaluation. The Gram stain
eye drop 1 hourly, Fluconazole 2% eye drop 1 hourly and revealed few gram positive organism and KOH mount did not
Homatropine 2% eye drop 3 times/day. show fungal hyphae. Corneal scraping sample was also sent
At the time of presentation patient had a visual acuity of for Real Time- Polymerase Chain Reaction (RT-PCR) to rule
ϐ
ͳ out Herpes Simplex Virus (HSV). Blood investigations were
(A) (B)
Figure 1A: 4KIJV G[G UJQYKPI UVTQOCN KPſNVTCVKQP YKVJ VTCEG J[RQR[QP Figure 1B: .GHV G[G UJQYKPI UVTQOCN KPſNVTCVKQP YKVJ EGPVTCN EQTPGCN UECT CPF
4mm hypopyon
www. dos-times.org 55
SNAPSHOT
Figure 2: RT-PCR – Highly positive for HSV-1 After a week low dose dexamethasone necrotizing stromal keratitis (NSK) is
(0.05%) eye drop 4 times/day was added often delayed and corneal perforation,
ordered including a complete hemogram, to the ongoing treatment. The stromal and visual morbidity is common3.
erythrocyte sedimentation rate, random ϐ Herpetic Eye Disease Study (HEDS)
blood sugar and HIV. A provisional reduce (Figure 3 A&B). The keratitis revealed the incidence of NSK to be
diagnosis of necrotizing stromal HSV healed with scarring in both the eyes 7%, immune-mediated nonnecrotizing
keratitis was made based on the history with complete resolution of hypopyon by keratitis to be 88% and mixed type to be
ϐǤ 20 days (Figure 4 A&B). The visual acuity 5% of the stromal disease4.
on eye ointment acyclovir (3%) 5 times/ ʹͲȀʹͲͲ ϐ
ǡ ϐ
ȋͲǤͷΨȌ counting at 3 metre in the left eye. Patient HSV stromal keratitis (HSK) can
4 times/day, eye drop homatropine was kept on oral acyclovir 400 mg twice a
ϐ
(2%) 3 times/day, eye drop carboxy- day as a prophylactic dose to prevent any non-necrotizing5,6. In necrotizing HSK,
methylcellulose (0.5%) 6 times/day, recurrence. an overlying epithelial defect is often
tablet acyclovir (400mg) 5times/day present, and the risk of stromal melting
and capsule doxycycline (100mg) 2 DISCUSSION and perforation is high. Both viral and
times/day. Patient was followed up every immune-mediated destruction of the
alternate day. Herpes simplex virus (HSV) keratitis cornea is implicated in necrotizing HSK.
is one of the major causes of infectious Conversely, in non-necrotizing HSK, also
By 3rd day patient was blindness in the developed countries. It known as immune or interstitial HSK, the
symptomatically better but clinically the has been estimated that nearly 500,000 epithelium is intact, and the pathology is
same. There was no growth in culture people in the USA are affected with thought to driven primarily by the host
media and blood investigations were all ocular HSV1. The impact of the disease in immune response. Recurrent episodes of
normal. Same treatment was continued. developing nations is currently unknown, stromal keratitis can lead to irreversible
On the 5th day the epithelial defect in although a study conducted by Kaur etal stromal scarring, neovascularization and
right eye had healed and reduced in in North India estimated the incidence vision loss.
the left eye. The RT-PCR was HSV was of HSV1 as 33.3%2. The diagnosis of
ǡ
ϐ The immune response to corneal
necrotizing stromal keratitis (Figure 2). HSV-1 infection is a major contributor
to the stromal damage and subsequent
scarring responsible for the blinding
complications of HSK. Thus, the standard
of care for treatment of HSK involves
antiviral therapy, often in the form of
oral acyclovir or valacyclovir, to block
potential viral replication, as well as
topical steroids, which broadly inhibit the
damaging immune response.
In this case there was bilateral
involvement simultaneously, which is not
very frequent. The incidence of bilateral
HSV keratitis has been documented to be
around 1.3%-12%7. Children are more
likely to experience bilateral HSV keratitis
with rates of 3.4–26%8. Though the
(A) (B)
Figure 3A: 4KIJV G[G UJQYKPI TGUQNXKPI UVTQOCN KPſNVTCVKQP YKVJ TGUQNXGF J[RQR[QP Figure 3B: .GHV G[G UJQYKPI FGETGCUKPI UVTQOCN KPſNVTCVKQP CPF
receding hypopyon
56 DOS TIMES - NOVEMBER-DECEMBER 2016
SNAPSHOT
(A) (B)
Figure 4A: 4KIJV G[G UJQYKPI UECTTGF KPſNVTCVG Figure 4B: .GHV G[G UJQYKPI UECTTGF KPſNVTCVG YKVJ PGCTN[ TGUQNXGF J[RQR[QP
diagnosis was made on the basis of history helped us in clinching an early diagnosis. controlled trial of oral acyclovir for
of recurrent episodes of keratitis along ϐ
herpes simplex stromal keratitis.
ϐǡ therapy can lead to better clinical ͳͻͻͶǢͳͲͳǣͳͺͳǦͺʹǤ
ϐ Ǥ Ǧ outcomes. ͷǤ
ǡ
Ǥ ϐ
shown to be a powerful molecular tool of herpes simplex virus keratitis.
for the diagnosis of necrotizing herpes REFERENCES ͳͻͻͻǢͳͺ ǣͳͶͶǦͷͶǤ
stromal keratitis9Ǥ Ǧ
ϐ
Ǥ
Ǥ ϐ
and sensitive to viruses than normal 1. Lairson DR, Begley CE, Reynolds TF, simplex virus keratitis and anterior
PCR, and can be used to detect the virus Wilhelmus KR. Prevention of herpes Ǥ ͳͻͻͻǢ ͳͺǣͳʹǦͶ͵Ǥ
more quickly at lower concentration to simplex virus eye disease A cost 7. Liesegang TJ. Herpes simplex virus
help make diagnosis sooner. Topical and effectiveness analysis. Arch Ophthalmol epidemiology and ocular importance.
systemic acyclovir for treatment of NSK ʹͲͲ͵ǢͳʹͳǣͳͲͺǦͳʹǤ ʹͲͲͳǢʹͲǣͳǦͳ͵Ǥ
facilitated healing of ulceration. This was 8. Chong EM, Wilhelmus KR, Matoba AY et
clinically demonstrated by healing of 2. Kaul R, Gupta N, Baveja UK. al. Herpes simplex keratitis in children.
epithelial defect and reduction of stromal Seroprevelance of HSV 1 and HSV 2 Am J Ophthalmol 2004 138:474-5.
ϐǤ
infections in family planning clinic 9. Ma JX, Wang LN, Zhou RX, Yu Y, Du TX.
after initial antiviral therapy decreased Ǥ
ʹͲͲͷǢ͵ǣ͵ͲǦ Real-time polymerase chain reaction
ϐ 9. for the diagnosis of necrotizing herpes
recovery10. stromal keratitis. Int J Ophthalmol
3. Knickelbein JE, Hendricks RL, ʹͲͳ ͳͺǢͻǣͺʹǦǤ
Thus in this case strong clinical Charukamnoetkanok P. Management of 10. Dutt S, Acharya M, Gour A, Sapra N,
judgement supported with a new and herpes simplex virus stromal keratitis ǡ Ǥ
ϐ
effective laboratory diagnostic technique .An evidence based review. Surv of oral and topical acyclovir in herpes
ʹͲͲͻǢͷͶǣʹʹǦ͵ͶǤ simplex virus stromal necrotizing
Ǥ
ʹͲͳǢ
4. Barron BA, Gee L, Hauck WW, 64:292-5.
Kurinij N, Dawson CR, Jones DB.
Herpetic Eye Disease Study. A
1. Cornea & Refractive Surgery Services, Dr. Shroff ’s Charity Eye Hospital, New Delhi
2. Department of Pathology & Laboratory Services, Dr. Shroff ’s Charity Eye Hospital, New Delhi
Dr.Abhishek Dave1 MD, FICO, FMRF Dr. Hafsa Bashir1 MS, FSCEH Dr.Arpan Gandhi2 MD (Pathology)
Financial Interest: ϔ
Ȁ
Ǥ
www. dos-times.org 57
DIAGNOSTICS DISCUSSION
ROLE OF HISTOPATHOLOGY IN DIAGNOSIS OF OCULAR SURFACE
SQUAMOUS NEOPLASIA MASQUERADES
Sugandha Goel, Tapasya Singha, Uma Sridhar
A60 year old male patient presented to our out Figure 1: Left eye showing gelatinous mass on nasal conjunctiva with
patient department with chief complaints of UWRGTſEKCN MGTCVKP CPF GPETQCEJKPI QP VJG EQTPGC
redness, pain and photophobia in left eye since
few weeks. There was no history of associated
discharge, or watering. He was diagnosed to
have pterygium elsewhere. His BCVA was 6/6 in
both eyes for distance. On inspection of the anterior segment,
ϐ
the nasal peripheral cornea (Figure 1). The peripheral cornea
showed an elevated mass with punctate staining. The corneal
part of the mass showed faint staining with Rose Bengal. The
overlying conjunctiva was injected. The rest of the ocular
examination was within normal limits. A provisional diagnosis
of conjunctival dysplasia was made in the left eye.
In view of the atypical appearance of the lesion and
presence of keratin, an excision biopsy was done. Corneal lesion
was removed with alcohol kerato epitheliectomy. Conjunctival
lesion was excised with adequate margins (4mm) using ‘no-
touch’ surgical technique and the defect was covered with
amniotic membrane graft. Fibrin glue was used to adhere the
amniotic membrane to the underlying sclera. 2 cycles of inverse
freeze thaw cryotherapy was applied at the margin of excised
conjunctiva. Intraoperative topical mitomycin C 0.02% was
applied to the bare sclera.
Histopathological examination of the specimen revealed
acanthotic epithelium with squamous metaplasia, occasional
dyskeratotic cells, parakeratosis, and hyperkeratosis. Multiple
ϐ Ǥ
present. The basement membrane was intact, and a diagnosis of
conjunctival squamous cell carcinoma in situ was made (Figure
2). Patient was treated with six cycles of topical mitomycin C
0.02%.
CASE 2 Figure 2: Histopathology of case 1, conjunctival mass lesion showing
CECPVJQVKE GRKVJGNKWO YKVJ USWCOQWU OGVCRNCUKC NQUU QH RQNCTKV[ CPF
A 65 year old male patient came to our hospital with the OWNVKRNG OKVQVKE ſIWTGU
chief complaints of redness and irritation in left eye. His BCVA
was 6/9 in both eyes for distance. Ocular examination revealed with no breach of basement membrane was made. The patient
ϐ
was advised topical chemotherapy but was unfortunately lost
conjunctiva from 6 o’ clock to 12 o’ clock position in the left eye. to follow up.
It was associated with pigmentation (Figure 3). A provisional
diagnosis of pterygium was made. Due to presence of associated OSSN presents as a spectrum from simple dysplasia to
pigmentation, a suspicion of conjunctival dysplasia was made carcinoma in situ to invasive squamous cell carcinoma involving
and biopsy of the pterygium tissue was done. Wide margin the conjunctiva as well as the cornea1. OSSN has been reported
excision of conjunctiva was done and the corneal part was to masquerade as chronic blepharoconjunctivitis, chronic
excised by alcohol keratoepitheliectomy. Two cycles of inverse
freeze thaw cryo therapy was applied to the excised margin
of conjunctiva. The bare sclera was covered with amniotic
ϐ Ǥ
Histopathology of the conjunctival lesion revealed an
irregular epithelial thickening associated with dyskeratosis
and full thickness dysplasia. There was loss of polarity and
ϐ
epithelium (Figure 4). A diagnosis of full thickness dysplasia
www. dos-times.org 59
DIAGNOSTICS DISCUSSION
Figure 3: .GHV G[G UJQYKPI RVGT[IKWO YKVJ RKIOGPVCVKQP GZVGPFKPI Figure 4: Histopathology of case 2, showing an irregular epithelial
from 12 o’ clock to 6 o’ clock hours thickening associated with dyskeratosis and full thickness dysplasia
YKVJ PWOGTQWU OKVQVKE ſIWTGU
conjunctivitis, corneal ulcer, pterygium, There are few case studies regarding highlights the importance of keeping
necrotizing scleritis, sclerokeratitis the association of pterygium with OSSN. In an index of suspicion for squamous cell
and as peripheral ulcerative keratitis2. a study by Sevel and Sealy,5 investigating neoplasia in any atypical presentation of
Akpek et al.3 showed that ocular surface the association of pterygium with CIN and the more common conjunctival lesions
malignancies may involve the conjunctiva SCC, 12 cases of SCC and 17 cases of CIN
diffusely and can masquerade as chronic were shown to arise in 100 pterygium such as pterygium.
conjunctivitis. Lindenmuth et al.4 cases, indicating that distinguishing a
reported a case of a 64-year-old white “reactive pterygium” from CIN and SCC REFERENCES
man who presented with necrotizing ϐ
Ǥ
scleritis with scleral perforation and 1. Lee GA & Hirst LW. Ocular surface squamous
uveal prolapse. Pathologic examination Mirza et al.6 reported a case of Ǥ ͳͻͻͷǢ͵ͻǣͶʹͻǤ
revealed squamous cell carcinoma of the invasive squamous cell carcinoma of the
conjunctiva invading adjacent corneal
ϐ 2. B Ramasamy, S A Quah, M S Wishart, P Hiscott.
stroma and ciliary body. as a pterygium. Olasode et al.7 reported Temporal pterygium: benign or not?. Br J
a case of invasive SCC initially diagnosed ʹͲͲͷǢͺͻǣ ͳͷ͵͵ǦͶǤ
Pterygia can always be diagnosed ϐ ǡ
easily by a simple examination and that a high index of suspicion is crucial 3. Akpek EK, Polcharoen W, Chan R, et al. Ocular
thereby when excised, pathologic to prevent a delay in the diagnosis of surface neoplasia masquerading as chronic
evaluation of the lesion is thought an invasive condition and not to cause
Ǥ ͳͻͻͻǢͳͺǣʹͺʹȂ
not to be needed because of the exact complete involvement of the eye. 88.
diagnosis. However, conjunctival Similarly, Degrassi et al.8 presented a
intraepithelial neoplasia (CIN), a case report of a 53 year old patient in 4. Lindenmuth KA, Sugar A, Kincaid MC, Nelson CC,
precursor of conjunctival squamous cell which the histopathology of an apparent Comstock CP. Invasive squamous cell carcinoma
carcinoma (SCC), is an important clinical pterygium showed the presence of CIN. of the conjunctiva presenting as necrotizing
entity that should be ruled out in the Zhang et al.9 described a patient who scleritis with scleral perforation and uveal
diagnosis of a pterygium1. Moreover, this was misdiagnosed as conjunctivitis and Ǥ Ǥ ͳͻͺͺǢ͵͵ǣͷͲȂͶǤ
lesion may not be differentiated from a pterygium which was later found out to
pterygium clinically because of its similar be conjunctival SCC. 5. Sevel D, Sealy R. Pterygia and carcinoma of
appearance. Because CIN may lead to an the conjunctiva. Trans Ophthalmol Soc UK
invasive type of conjunctival SCC that can Even in the absence of nodular limbal ͳͻͺǢͺͺǣͷȂͷͺǤ
ϐ
ϐ
ǡ mass, subtle clinical hints including the
cases should be evaluated. presence of keratin and pigmentation are 6. Mirza E, Gumus K, Evereklioglu C, Arda H,
pointers to a diagnosis of OSSN. Our cases Oner A, Canoz O, et al. Invasive squamous cell
ϐ
as a pterygium: A clinicopathologic report. Eye
ǤʹͲͲͺǢ͵ͶǣͳͺͺȂͻͲǤ
7. Olasode BJ, Bankole OO, Adeoye AO. Invasive
squamous cell carcinoma: Case report. East Afr
ͳͻͻǢ͵ǣʹȂʹͺǤ
8. Degrassi M, Piantanida A, Nucci P. Unexpected
ϐ Ǥ
ͳͻͻ͵ǢͲǣͳͲͷͺȂͲǤ
9. Zhang Z, Li B, Shi J, et al. Intraocular extension
of conjunctival squamous cell carcinoma.
ʹͲͲǢʹʹͳǣʹͲͲȂʹͲ͵Ǥ
I-Care Hospital, Noida, U.P.
Dr. Sugandha Goel MBBS Dr.Tapasya Singha MBBS, DOMS Dr. Uma Sridhar MS, DNB, FRCS
Financial Interest: ϔ
Ȁ
Ǥ
60 DOS TIMES - NOVEMBER-DECEMBER 2016
INNOVATIONS
ADAPTERS IN SMART PHONE: HOW TO
MAKE YOUR OWN?
Dr.Ajay Shankar Kar MBBS, DNB
(CMC Vellore),FICARS, FRCS,FAICO (Cornea)
Consultant Ophthalmologist (Cornea and refractive surgeon),
Seven Hills Hospital,Visakhapatnam
In the Ophthalmology setting, phone slit lamp camera adaptor (eg. Eye /CIPKſ (KIWTG %QWTVGU[ YYY CTEVWTWUNCDU
taking pictures of the anterior
ǡ ǡ ϐ com
segment is of crucial use for iPhone adaptor, Steady iPix Telescope
ophthalmologists in their daily Photo adaptor for iPhone, Keeler portable 1TKQP 5VGCF[ 2KZ 6GNGUEQRG 2JQVQCFCRVGT
practice. Ophthalmologists rely slit lamp, iExaminer, Tiger Lens and Figure Courtesy: www.telescope.com
heavily of anterior segment Skylight) ranges from USD 75.00 to USD Ͷ ͷǤ ϐ
camera for recording of progression 520.00. The estimated cost for a MIY instruments, including binoculars,
of disease, documentation for case smart phone slit-lamp adaptor is USD 4.00 microscopes, telescopes and most
presentation and discussion, referrals (300 RS). A conventional slit lamp camera instruments with eyepieces. There is no
to colleagues or subspecialty clinic and needs to be serviced and maintenance extra lens. The adapter requires that the
education for junior doctors and patients. needs to be done which incurs additional iPhone be slipped in and the phone’s
A conventional slit lamp camera is usually cost to the ophthalmologist. By using the
used for taking good quality pictures smart phone slit lamp camera, there is
of the eye. The problem with slit lamp virtually zero maintenance.
camera is that it is expensive and usually
immobile. The use of the smart phone in Portability
ophthalmology is more common than ever
before1–5. Although most ophthalmology In comparison to the conventional
clinics are equipped with slit lamp but slit lamp camera, the smart phone slit
not all clinics are fortunate enough to
Ǥ ϐ
be equipped with a high quality anterior a pocket and when it is needed, it can be
segment slit lamp camera. Smart phones easily mounted to an already existing slit
are usually incorporated with high lamp during routine examination.
resolution cameras which are commonly
used by ophthalmologist capture pictures Ease of use
of the anterior segment of the eye. There
are several commercially available smart Conventional slit lamp camera is
phone adaptors to a slitlamp but they usually placed in a special room and
ϐ
not easily accessible but with the smart
slit lamp brands only6. It is to introduce phone slit lamp adaptor, it can easily be
an easy method to produce and use your used in any slit lamp at anytime.
own smart phone as a slitlamp anterior
Ǥ
ϐ
ǡ Patient will be explained of the
perform slit lamp photography by pulling anterior segment photography and
out your phone during clinic, without consent will be taken.
having to send a patient to another room
in order for someone else take the photos, Ease of Referrals
ϐ
ǡ
convenient for your patient7. By using the smart phone slit lamp
camera, pictures taken can be shared
ADVANTAGES OF SMART PHONE easily and securely to another colleague
for further management or opinion. It can
SLIT LAMP CAMERA: also be used by general practitioner who
has a clinic equipped with a slit lamp.
Cost saving and maintenance
DIFFERENT TYPES OF SLIT LAMP
Conventional slit lamp camera is ADAPTERS
expensive costing at about USD 15,000.00.
The commercially available smart ϐ ϐ
ϐ Ͷǡ
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