Editor-in-chief Editorial Capsule Innovations
3 Every End has a New Beginning 49 Pupil expansion redefined
M. Vanathi with Bhattacharjee Ring
Special M essage
Section Editors 5 President’s Message M onthly Meeting Korner
Cataract & Refractive Retina & Uvea 55 Corneal Collagen Cross-
Umang Mathur Pradeep Venketesh Featuring Sections Linking with Smile
Saurabh Sawhney Manisha Aggarwal Lenticule: A New Modality of
Sanjiv Mohan Shahana Majumdhar Cataract Treatment for the Ultrathin
S. Khokhar Rohan Chawla 7 Primary reverse optic capture Keratoconic Cornea
Cornea & Oular Surface Ravi Bypareddy for negative dysphotopsia
Uma Sridhar Ophthalmoplasty & 9 Femtosecond laser assisted Diagnostics Discussion
Deepa Gupta Ocular Oncology cataract surgery: where do 59 Posterior Keratoconus
Umang Mathur Neelam Pushker we stand now?
Ramendra Bakshi Maya Hada
Manisha Acharya Sangeeta Abrol Cornea Clinical Spotlight Retina
Glaucoma Rachna Meel
Dewang Angmo Squint & 13 Corneal Collagen Cross Linking – 61 Post Operative
Reena Sharma Neuro-ophthalmology Endophthalmitis–An Update
Sunita Dubey Swati Phuljhale Current Perspectives
Viney Gupta Zia Chaudhuri
Kanak Tyagi Suma Ganesh R efractive Surgery DOS TIMES Quiz
17 CXL Plus - Corneal Collagen 69 QUIZ - Episode I
Delhi Advisory Board Cross-Linking Combined with
Y.R. Sharma Mahipal Sachdev Refractive Surgery DOS Crossword
Atul Kumar Radhika Tandon 21 Small Incision Lenticule 71 DOS CROSSWORD-
P.V. Chadha Jolly Rohtagi Extraction : The future of Episode I
Noshir M. Shroff J.C. Das refractive surgery
Rajendra Khanna B.P. Gulliani Quick Picks
Vimla Menon Ritu Arora Ocular Surface 73 Oculocardiac Reflex
H.K. Yaduvanshi Kamlesh 25 Ocular Surface and
Anita Panda G.K. Das Glaucoma Correspondence Portal
Pradeep Sharma B. Ghosh 77 Ethics of Live Surgery
Ramanjit Sihota Tanuj Dada Oculoplasty
Harish Gandhi Abhishek Dagar 29 Periorbital Necrotising Fasciitis News Watch
Anup Goswami Sarita Beri 78 DOS Credit Points
Rajpal P.K. Sahu Retina 79 DOS Members -
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B. Ghosh Taru Dewan Syndrome – Pathogenesis, 80 DOS Library ONLINE
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Chandna Chakraborti Mangat Ram Dogra RAPDX
Sushmita Shah D. Ramamurthy
Sushmita Kaushik T.P. Lahane Snapshot
Pravin Vadavalli Samar Basak 45 Ocular Decompression
Somshiela Murthy Cyrus Mehta
Sri Ganesh Mahesh Shanmugam Retinopathy
M.S. Ravindra J. Biswas
Rohit Shetty Srinivas Rao www. dos-times.org 1
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Tejas Shah Gunjan Prakash
Sujith Vengayil Pravin More
M. Kumaran Sajjad Ahmed Shiekh
Punith Kumar Santhan Gopal
Elankumaran
DOS Correspondents
Anita Ganger Manzoorul Mehdi
Rebika Dhiman Shikha Yadav
Manish Mahabir Manu Saini
Shiva Gantyala Meenakshi Wadwani
Sridevi Medha Sharma
Saranya
DOS TIMES
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DOS Times will hitherto be published once every two months
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ISSN 0972-0723
DOS EXECUTIVE MEMBERS
Executive Committee:
DOS Office Bearers
Dr. Cyrus M. Shroff Dr. Rishi Mohan Dr. M. Vanathi
President Vice President General Secretary
Dr. Arun Baweja Dr. Vipul Nayar Dr. Ruchi Goel Dr. Devn Tuli
Joint Secretary Treasurer Editor Library Officer
Ex-Officio Members Dr. Sanjeev Gupta
Ex-Treasurer
Dr. Rajendra Khanna Dr. Rajesh Sinha
Ex-President Ex-Secretary 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
DOS HALL OF FAME Tejpal Saini B. Pattnaik Dos General Secretaries
DOS PRESIDENTS Satish Sabharwal Satinder Sabharwal
N.C. Singhal A.K. Grover Hari Mohan Arun Sangal
S.N. Mitter A.C. Chadha Madan Mohan J.C. Das R.S. Garkal R.V. Azad
H.S. Trehan M.S. Boparai Pratap Narain Gurbax Singh S.R.K. Malik B. Ghosh
Tej Pal Saini N.N. Sood (Brig.) R.C. Sharma Noshir M. Shroff Madan Mohan Mahipal Sachdev
L.P. Agarwal P.K. Jain B.N. Khanna Mahipal S. Sachdev J.C. Bhutani Atul Kumar
D.C. Bhutani L.D. Sota R.N. Sabharwal Lalit Verma S.C. Sabharwal Lalit Verma
R.C. Aggarwal L.D. Sota N.L. Bajaj S. Bharti A.C. Chadha Dinesh Talwar
S.N. Kaul S.K. Angra Mathew M. Krishna Sharad Lakhotia Pratap Narain Harsh Kumar
S.N. Kaul D.K. Mehta Prem Prakash P.V. Chadha S.K. Angra J S. Titiyal
H.S. Trehan Y. Dayal D.K. Sen B.P. Guliani G. Mukherjee Harbansh Lal
Hari Mohan K.P.S. Malik P.K. Khosla Harbansh Lal H.K. Tewari Namrata Sharma
R.S. Garkal R.B. Jain K. Lall J S. Titiyal R. Kalsi Amit Khosla
J.C. Bhutani G. Mukherjee A.K. Gupta Rajendra Khanna D.K. Mehta Rohit Saxena
S.R.K. Malik R.V. Azad Cyrus Shroff P.C. Bhatia Rajesh Sinha
K.P.S. Malik M. Vanathi
Sincere thanks to all DOS OFFICE STAFF : Office Secretary: Parveen Kumar w DOS Accountant: Sandeep Kumar w DOS TIMES Assistant: Sunil Kumar
DJO Assistant: Varun Kumar w Library Attendant: Niyaj Ahmad w Office Attendant: Harshpal
2 DOS Times - July-August 2015
Editorial Capsule
Every End Has A New Beginning
“For last year’s words belong to last year’s language
And next year’s words await another voice.
And to make an end is to make a beginning.”
(Little Gidding)”
― T.S. Eliot
Dear Members
I wish to thank all DOS members for the loving support and trust in entrusting
me with the task of carrying forward DOS for the years 2015 - 2017. It is indeed an
honour to be able to render my service to DOS as the first elected woman secretary
of the society. I promise to strive hard to keep the DOS flag flying high and take it to
greater heights.
Delhi Ophthalmological Society has passed through yet another remarkable Dr. M.Vanathi
period of prolific academics under the leadership of the past Presidents Padmashri
Prof. J.S. Titiyal & Dr. Rajendra Khanna and past Secretary Dr. Rajesh Sinha. I hope not
to see this as an end but yet another beginning to continued commitment to gallop
forward with a pace that will remain unmatched. With the launch of another set of years of productive and abundant academics,
I look forward to unsurpassed energy, zeal and support from all the members. With challenges of condescending politics, rising
competition from other societies, an abundance of conferences and academic activities, the task at hand is no less formidable.
Under the able leadership of President Dr Cyrus M Shroff, we have an assembly of excellent executive. Let us hope that together
with your supporting strength we can take DOS to touch greater heights in defining the frontiers of ophthalmology in this term.
At the start of our academics, DOS TIMES 2015 – 2017 as the official bulletin magazine of our society, dons a refreshing
new look; In an attempt to redefine the popularity of DOS TIMES to capture all facets of ophthalmology and in compliance to
popular demands to cater to all subspecialties in every issue, DOS TIMES, now published as six issues in a year, wil feature
all subspecialty articles of current interest. Snap shot will carry a photo-feature report of an interesting case. Innovations
section will cover a new technique or device. Diagnostics discussion will feature a brief investigative highlight of an ophthalmic
case scenario. Practice requisites will highlight an investigative modality of academic and practical interest. New section of
ophthalmic Crossword is also being added with this issue. News Watch will present all news related to the society. We are also
attempting to begin an Industry watch and classified section.
With society strength of Delhi Members exceeding over 1600, I look forward to all DOS members active participation in all
DOS activities and enhance the essence of its flavor and success. I would also appreciate all Delhi members of DOS to contribute
high quality scientific content to all the academic endeavors of DOS: DOS TIMES, DJO and scientific paper presentations of our
conferences. I look forward to all members to put forth their comments and suggestions for improving all academic activities
of DOS.
Dr. M. Vanathi MD
General Secretary DOS (2015-2017)
&
Cornea, Cataract & Refractive Services
Dr. R.P. Centre, AIIMS, New Delhi
www. dos-times.org 3
Special message
Special Message from President
Dear Friends,
Greetings from the new Executive. Welcome to a brand new Academic Year of DOS. At the
outset, I would like to congratulate the previous Executive especially Dr. Rajendra Khanna &
Dr. Rajesh Sinha, for a very successful year and a highly successful AIOS conference which has
set a new benchmark. The Annual Conference of DOS also went off very well and was very
well attended despite coming close on the heels of the AIOS meeting. The incident of assault
on a resident doctor by performer Mika Singh at the Gala Dinner was extremely unfortunate &
totally unacceptable in civil society. We appreciate the cooperation of the Delhi Police and his
arrest is a vindication of our stand on the matter.
Some of the areas of focus for the society in the coming year would be :-
1. To bring the DOS house matter to a successful, financially sustainable conclusion which Dr. Cyrus M. Shroff
could be of real value to the society and its members.
2. Strengthening social responsibility projects related to common ocular disorders like
corneal blindness, glaucoma and diabetic retinopathy.
3. To evolve & publish PPP (preferred practice pattern) and standard protocols for common ophthalmic procedures – these
will help raise clinical standards and also be valuable in medico-legal situations.
4. Evolve specific guidelines and standards for NABH Accreditation for ophthalmology.
5. To review our systems & processes relating to election, monthly annual & mid-year meeting and to continually improve
and elevate our standards.
The academic calendar kicks off with the first monthly meeting at R.P. Centre in July. The meeting at R & R in August will be
preceded by the AGM. On 22nd August, we have a talk by Dr. Naresh Joshi, a distinguished Oculoplasty surgeon from the U.K.
The Winter Conference is from 5-6 December at Manekshaw Centre, the DOS teaching program on 23rd & 24th January 2016
& the Annual Conference from 15-17 April 2016.
Academics is the core activity of our society & I request & exhort all of you to attend these meetings in large numbers.
I alongwith the Secretary, Dr. Vanathi & the entire executive are committed to making this another very successful year for
DOS.
Do write in with your suggestions on any aspect of the society’s functioning. We have to ensure that DOS maintains its
primacy among all state ophthalmic societies of the country & that our academic programs are of the highest quality.
With best wishes,
Cyrus M. Shroff
President, DOS
&
Director
Vitreo-retinal Services
Shroff Eye Centre,
Kailash Colony, New Delhi
www. dos-times.org 5
Cataract
Primary Reverse Optic Capture for
Negative Dysphotopsia
Various theories have been formulated to explain the
mechanism of action of reverse optic capture but the exact
Dr. Priya Narang Ms etiology remains elusive. Masket et al4 described that a shadow
Narang Eye Care & Laser Centre,
Ahmedabad, Gujarat, India is generated due to the overlap of the anterior capsulorhexis
onto the anterior surface of the IOL and is due to the
reflection of the anterior capsulotomy edge projected onto
Negative dysphotopsia symptoms when the nasal peripheral retina. Performing reverse optic capture
experienced by the patient is very disheartening eliminates this reflection, and hence the symptom of negative
for both the surgeon and the patient alike. The dysphotopsia abates. Whereas Holladay et al6 suggest that after
patients with negative dysphotopsia complain
of a temporal dark shadow perceived in their reverse optic capture, the anterior capsule comes in direct
field of vision. In fact it’s like a punishment
contact with the posterior capsule and eventually both surfaces
become translucent due to opacification, thereby eliminating
that is offered to the surgeon for performing a perfect in-the- or filling the shadow due to scattering effect. Inspite of varied
bag IOL implantation with good capsulorhexis that adequately explanation that have been described regarding the mechanism
covers the periphery of the optic of the IOL all around. As it is of action of reverse optic capture, the fact remains that reverse
a subjective phenomenon, it is difficult to predict as to which optic capture has been accepted by all to be very effective in
patients will experience negative dysphotopsia following abating the symptoms of negative dysphotopsia.
an uneventful surgery. Some In a prospective study of primary reverse optic capture
(Figure 1) at Narang Eye care
patients may be particularly The patients with negative dysphotopsia and Laser centre, Ahmedabad,
vulnerable or particularly
sensitive to dysphotopsia and complain of a temporal dark shadow primary reverse optic capture
may require additional surgical perceived in their field of vision. with capsular tension ring
implantation was performed in
treatment.
The main surgical interventions all the cases that experienced
The symptoms of negative negative dysphotopsia in
dysphotopsia often abate that have been described for the the previous eye and who
slowly over a period of time and management of negative dysphotopsia underwent SROC for the same
that the incidence of negative
dysphotopsia in the immediate are IOL exchange, placing a secondary in the previous eye. None of
postoperative period is always piggyback IOL in sulcus and reverse the patients complained of
negative dysphotopsia in the
more. Osher1 reported an
incidence of 15.2% on the optic capture. postoperative period in the eyes
that underwent primary reverse
first postoperative day, which
optic capture with capsular
decreased to 2.4% after 2 years. Adequate counseling of the
tension ring implantation. Some studies formulate that negative
patient is a must and they should be explained to wait before
dysphotopsia appears to be more related to the patient’s
any surgical measure can be adopted for the same. Symptoms of
anatomical structure, which is expected to be the same in the
negative dysphotopsia have been observed to either disappear
or decrease in intensity in some of the cases, but they often
persist in few cases.
The main surgical interventions that have been described
for the management of negative dysphotopsia are IOL exchange,
placing a secondary piggyback IOL in sulcus and reverse optic
capture2-4. Some studies have also described suturing the
bag-IOL complex to the iris tissue but this is not effective in
completely eliminating the symptom of negative dysphotopsia.
Some surgeons also suggest that laser anterior capsulotomy
also helps to overcome the symptoms of negative dysphotopsia5.
In reverse optic capture, the optic of the IOL is prolapsed out of
the confines of the capsular bag. The optic of the IOL is made to
rest on the margins of anterior capsulorhexis. This procedure
when performed in the late postoperative period is known as
secondary reverse optic capture and when it is performed as Figure 1: Intraoperative image of primary reverse optic capture. A
a prophylaxis during the initial surgery, then it is known as a capsular tension ring is placed in-the bag followed by prolapsing of a
primary reverse optic capture. 3-piece intraocular lens out of the capsular bag
www. dos-times.org 7
Cataract
other eye7. Although it is essential to state opacification formation. Although it is yet the 180° opposite edges can be easily
that negative dysphotopsia symptoms essential to mention that adequate clean placed with haptics remaining confined
may not be bilateral. up of the peripheral epithelial cells is to the capsular bag. Clinically, difficulty in
a must and capsule polisher should be entrapment of a one-piece IOL is observed
In cases of primary reverse optic employed for the same.
capture placing a capsular tension ring in in primary reverse optic capture because
the bag is recommended and this concept It is always easy to prolapse a 3-piece
was originally conceived by Masket et IOL out of the bag as compared to a 1-piece the edges of the capsulorhexis margin in
al. The use of a capsular tension ring is IOL. For cases that undergo a primary
effective because it helps to distend the reverse optic capture, it is recommended a freshly operated eye tend to be slippery
capsular bag in a freshly operated eye, to use a 3-piece IOL, whereas, for as compared with the fibrotic capsule
especially when the optic is prolapsed secondary reverse optic capture the margin in cases of secondary reverse
out of the confines of the capsular bag. situation is completely different as
The capsular tension ring prevents the usually a 1-piece IOL is found to be well optic capture that were operated over a
collapse and shrinkage of the capsular placed in the bag as it was intended for in-
bag and it also helps to prevent the the-bag-implantation. With a one-piece period of time. A new anti-dysphotopic
migration of the peripheral epithelial IOL, it is difficult to place the entire 360° IOL8 has been designed by Dr. Masket
cells and subsequent posterior capsular of optic above the anterior capsular rim,
that has a peripheral groove to facilitate
the entrapment of the anterior capsule
in the groove. Until detailed reports are
published, surgeons should continue to
use a three-piece IOL9.
REFERENCES 5. Cooke DL, Kasko S, Platt LO. Resolution of negative
dysphotopsia by laser anterior capsulotomy. J Cataract Refract
1. Osher RH. Negative dysphotopsia: long-term study and Surg 2013; 39:1107–09.
possible explanation for transient symptoms. J Cataract
Refract Surg 2008; 34:1699–1707. 6. Holladay JT, Zhao H, Reisin CR. Negative dysphotopsia: the
enigmatic penumbra. J Cataract Refract Surg 2012; 38:1251–
2. Vamosi P, Csakany B, Nemeth J. Intraocular lens exchange in 65.
patients with negative dysphotopsia symptoms. J Cataract
Refract Surg 2010; 36:418–24. 7. Schwiegerling J. Recent developments in pseudophakic
dysphotopsia. Curr Opin Ophthalmol 2006;17:27–30.
3. Ernest PH. Severe photic phenomenon. J Cataract Refract Surg
2006; 32:685–86 . 8. Masket S. Solving the problem of negative dysphotopsia. A
new IOL design might be the answer. CRST 2014 May.
4. Masket S, Fram NR. Pseudophakic negative dysphotopsia:
surgical management and new theory of etiology. J Cataract 9. Narang P, Narang S. Primary reverse optic capture with
Refract Surg 2011; 37:1199–1207. implantation of capsular tension ring to prevent pseudophakic
negative dysphotopsia. J. Cataract Refract Surg. 2015;41:891-92.
Financial Interest: The author does not have any financial interest in any procedure/product mentioned in this manuscript.
8 DOS Times - July-August 2015
Cataract
Femtosecond Laser Assisted Cataract
Surgery:Where Do We Stand Now?
Anita Ganger, M. Vanathi, Radhika Tandon
This new femtosecond laser technology is better than manual
phacoemulsification surgery by providing more accuracy, repeatability and
consistency in results along with the option of customization of various parameters.
Cataract has been documented to be the most Ø Difficulty in subsequent steps of surgery due to imperfect
significant cause of bilateral blindness and capsulorhexis.
contributes 50-80% for that in India1-2. Number of
cataract surgeries have increased to 3.9 million per Ø Damage to endothelium due to excessive use of phaco
year in 2003 as compared to 1.2 million in 1980s, power especially in hard/advanced cataracts.
which will further increase to around 32 million
by the year 2020 as estimated by World Health Organisation Ø Difficulty in mechanical manipulations in cases with weak
(WHO)3,4. zonules.
Currently manual cataract is being done in most of the
patients which is safe and effective, but surgical outcomes Ø Lack of accuracy in accessing depth, position, length,
mainly depend on the surgeon’s skills and experience. and shape of corneal relaxing incisions for correction of
Decreased visual outcomes can occur due to occurrence of astigmatism.
potentially serious complications such as injury to the cornea, Lasers have been utilized in cataract surgery since the
iris, anterior and posterior lens capsules and vitreous loss.
The most critical step in cataract surgery is capsulorhexis, time when Krasnov (1970s) reported a laser modality for
or continuous curvilinear capsulotomy which is required for phacopuncture5 which eventually led to investigations into
lens removal and also to get a route for placement of IOL in femtosecond laser (FSL) assisted cataract surgery (FLACS).
the bag. Proper size, shape and centration of capsulorhexis FLACS represents a new era in cataract surgery which in recent
help in proper hydrodissection of lens, its removal, cleaning of times is heralded as, “The most important evolution since the
cortical matter, IOL centration and also inhibit post capsular transition to phacoemulsification”6.
opacification.
In multiple situations like smaller pupillary diameter, The FSL having wavelength of 1053 nm lies in the near-
shallow anterior chamber depth, poor visibility of red reflex infrared spectrum, which pass through optically clear tissues
due to advanced cataracts, in cataract with weak zonules, without getting absorbed at low power densities so it is
perfect capsulorhexis formation is a big challenge even for useful in ocular surgery. Its ultrashort pulses in the domain of
experienced surgeon. In era of multifocal and toric IOL’s the femtoseconds (1 femtosecond = 10−15 seconds) can cause tissue
perfect central alignment of IOL is of utmost importance, which destruction with precision without damaging surrounding
depends mainly on the accuracy of capsulorhexis. tissues due to less energy requirement. FSL was approved by the
The drawbacks of manual cataract surgeries as compared U.S. Food and Drug Administration, initially for use in lamellar
to femto-laser assisted cataract surgery (FLACS) include the corneal surgery and later on in 2010 they had been approved
following: for cataract surgery also. Femtosecond lasers are based on
Ø Formation of sub optimal corneal incisions which can photo disruption principle (Figure 1) where highly focused
results in fluid leakage and increases the risk of infection femtosecond laser pulses create plasma which rapidly expands
in a cavitation bubble and separates target tissue. Femtosecond
lasers increase the precision and reproducibility of various
steps of the cataract surgery procedure and also increase
patient safety as well as the accuracy of refractive outcomes7,8.
However, there still exists the question of its widespread utility,
Figure 1(A): Showing corneal tissue absorbing femtosecond laser energy and result in plasma formation. 1B: Showing plasma (having electrons and
ionized molecule) expansion to create cavitation bubble. 1C: Showing the separation of the tissues due to separation force of the cavitation bubble.
www. dos-times.org 9
Cataract
accessibility and affordability. Various whole procedure are the ideal candidate Ø Presence of any material like
types of FSL machines platforms used for for FLACS. exudation and blood in the anterior
FLACS (Table 1). chamber
FLACS is not recommended in the
Who are the patients suitable following conditions: Ø Residual, recurrent, active ocular or
for FLACS? Ø Paediatric group of patients eyelid disease, including any corneal
Ø Any corneal disease where abnormality i.e recurrent corneal
Patients who can lie flat and erosion and basement membrane
motionless in a supine position on applanation of the cornea or disease
operating table, can tolerate topical transmission of laser light is not
anaesthesia as well as understand the possible Ø Presence of descemetocele with
Ø In poorly dilating pupil impending corneal rupture
Table 1: Comparison of femtosecond laser-assisted cataract surgery (FLACS) platforms12
Features Catalys Lensx Lensar Victus
Pulse frequency 120 50 80 Up to 160
(KHz)
FDA approvals Corneal C arcuate Corneal C arcuate Corneal C arcuate Corneal C arcuate
incisions, anterior incisions, anterior incisions, anterior
capsulotomy, capsulotomy, capsulotomy, incisions, anterior
lens fragmentation lens fragmentation, lens fragmentation
corneal capsulotomy,
flap corneal flap
Arcuate incisions Surface and intrastromal Surface and intrastromal Surface and Capable of surface
or stromal (approved
(type) intrastromal for surface)
Patient interface Liquid Optics, Softfit, curved lens, Robocone, “Dual modality,” curved
design nonapplanating, liquid applanating, 1-piece, lens applanating 2-piece,
interface, 2-piece, vacuum nonapplanating, spherical, solid C liquid,
docking vacuum docking fluid interface, 2-piece, vacuum docking
vacuum docking
Patient interface Inner diameter, 13.5 mm; Inner diameter, 12.5 mm; Inner diameter O 12.7 Curved PI O 12 mm;
dimensions inner suction skirt, outer diameter, 19.8 mm mm; inner
14.1 mm; outer suction outer diameter, 24.0 diameter suction clip,
skirt, 23.0 mm mm 15.5 mm; outer diameter
suction clip, 21 mm
Docking Ocular surface bathed in Curved applanation, no No corneal applanation Soft docking for
saline solution, no corneal glaucoma capsulotomy and lens
applanation, no glaucoma contraindication fragmentation, regular
contraindication (since Softfit PI) docking for corneal
incisions
IOP rise 10.3 mm Hg rise2,3 16.4 mm Hg rise Unknown Unknown
(Cionni, ASCRS 2012
presentation)
Ocular surface Automatic C user Manual Automatic (augmented Manual
visualisation adjustable (integral reality camera)
guidance)
Imaging type 3D spectral domain OCT, 3D spectral domain OCT, 3D ray–tracing CSI 3D spectral domain OCT,
video microscope and video microscope and (confocal structural video microscope and
FS laser to enable FS laser to enable illumintation) FS laser to enable
imageguided imageguided imageguided
cataract surgery cataract surgery cataract surgery
Integrated bed Yes No No Yes
*Soft docking: less applanation (thus lower vacuum) needed for capsulotomy and lens fragmentation; hard docking: full corneal applanation (higher
vacuum) necessary for corneal and arcuate incisions.
Dr. Rajendra Prasad Centre for Ophthalmic Sciences,All India Institute of Medical Sciences, New Delhi, India
Dr.Anita Ganger MS, FAICO Dr. M.Vanathi MD Dr. Radhika Tandon MD, DNB, FRCSEd
10 DOS Times - July-August 2015
Cataract
Ø Hypotonous eye due to any cause Treatment stage: Once the docking of astigmatism and corneal thickness
or the presence of any implant i.e and visualisation is complete treatment of that particular patient. These laser
corneal implant stage is initiated by constructing laser assisted incisions can also be titrated in
incisions in posteroanterior plane as per post op by selective opening of incisions
Ø Any contraindication due to which the principal of micro cavitation bubbles as per required additional effect found in
cataract surgery itself is not possible which scatter the laser beam and reduce post op by the surgeon.
the amount of energy reaching the retina.
Procedure After creating laser incisions lens removal Challenges and potential
The procedure of FLACS includes 4 and IOL implantation are performed complications of FLACS
steps: similar to manual phaco under strict
sterile conditions13. Although femtosecond lasers
• Preoperative planning has revolutionized the whole surgical
• Docking Additive benefits of FLACS procedure of cataract surgery by providing
• Imaging of anterior segment over manual cataract accuracy and being less technically
• Treatment stage surgery demanding, it still has its own technology
related issues or complications.
Preoperative planning by Major contribution of FLACS involves 1. Postural problems: Various femto
assessing anatomy of eye is of utmost in performing various corneal incisions,
importance and should be done with capsulorhexis of predetermined size cataract machines have different
special consideration to size of pupil after as well as shape and easy division of platforms for coupling/docking of
dilatation, anterior chamber depth along lens nucleus. These crucial steps of eye but the baseline necessity in all
with thickness of cornea and lens. After manual phaco are simplified by femto machines is the proper alignment
deciding about the type of intraocular cataract with precision due to OCT which can affect the outcomes due
lens the size, shape and centration of guided proper estimation of positioning to malpositioning of laser beams.
capsulorhexis can be planned. Surgeons of various landmarks of eye and as Patients with any back and neck
can customise type of lens fragmentation well as laser energy delivery. All these problems cannot lie flat on operating
as per the grade of cataract which will also measures possibly improve the accuracy table which further hinders the
effect phaco time and power required. and outcomes and will help to shift proper placement of interface on
To combat with the astigmatism either normal cataract surgery to refractive patient’s eye, can create problem
clear corneal incision, arcuate or limbal rehabilitation in future. in docking which can further
relaxing incision’s depth, length as well as compromise the imaging with OCT.
axis can be planned by using traditional Femto cataract helps in making So patients with severe postural
normograms. main phaco incision (uniplanar, biplanar problems are not to be planned for
and triplanar), paracentesis and arcuate femto cataract.
Docking is the next step after incision in terms of size, shape and depth 2. Loss of suction: Suction loss can
planning. It is similar to the docking as per preoperative plan. This helps happen during docking step of
procedure of laser refractive surgery. in getting more predictable refractive FSL. Compared to femto LASIK
But in this, a slight modification has been outcomes, although further studies are femto cataract causes less pressure
introduced by few developers of FLACS to required to prove this. rise while suction, so causes less
minimize the IOP rise issue. As its already discomfort to the patient in terms
known that in laser refractive surgery Capsulorhexis created by femto of pain and transient vision loss.
pressure rises to approximately > 80 cataract is round, symmetrical and with Patient with fixation problems like
mm of Hg9,10 which cannot be tolerated less chances of posterior extension which nystagmus cannot cooperate for
by adults and old patients undergoing allow surgeon to do further surgical the procedure. Few surgeons have
cataract surgery so machines like LENSX steps comfortably. Whether this produce done femtocataract under retro or
introduced a curved contact lens which any impact on post surgical spherical peribulbar block also but chemosis
applanates the cornea and reduces the refractive outcome or not is yet to confirm. induced by local anaesthesia can
IOP rise to 40 mm of Hg11 whereas certain cause difficulty in suction and
machines have succeeded to decrease IOP Nucleus division is the crucial step docking. Suction loss before and after
rise value to 15 mm of Hg only12. Various where lots of problems are anticipated capsulorhexis can cause obstruction
changes have been introduced in different to happen due to long learning curve for in imaging due to induction of bubble
laser machines to decrease this IOP rise various manual chopping methods. Femto during laser procedure. As the
which can prevent optic neuropathy cataract not only makes this challenging corneal incisions and capsulorhexis
especially in vulnerable older age group step easy and quick as well as it provides steps take very less time, chances of
of patients. various patterns like radial and cylinder suction loss are more after these two
which can be selected by surgeon as per steps.
Anterior segment live imaging: nuclear grade. Divided pieces can be 3. Inadequate pupillary dilatation:
Three dimensional, high resolution and aspirated very easily by phaco tip that too If pupil is not dilating well it can
wide field of anterior segment imaging with less energy use. cause difficulty in forming adequate
is done in this step. Visualisation of the size capsulorhexis. For FSL pupil
plane of incisions, corneal thickness, For the management of astigmatism, diameter should be > 5mm, as it
iridocorneal angle and anterior as well to make precise depth, position and further affects capsulorhexis size.
as posterior capsule of lens in respect to length of arc of arcuate incisions manually Phacoemulsification through small
planned positions is done with the help is still a big challenge which can be easily capsulorhexis is challenging. As we
of Fourier domain optical coherence managed by femto cataract. As incision of
tomography to ensure the accuracy and accurate depth, position and length can
safety of FLACS. be planned preoperatively as per amount
www. dos-times.org 11
Cataract & Refractive
know that after docking there are where there is associated lens tilt as compared to manual capsulorhexis.
and weak zonules. Fragmentation of lens types of
chances of further decrease in pupil 6. Additional time: As it is a 2 step
size which can make surgery even procedure additional time required fragmentation of lens: FSL provides
more difficult. In such cases either for FSL treatment increases the different fragmentation patterns for
dilation with strong mydriatic like surgical time. But this issue can different grades of nuclear cataract like
atropine 1% eye drops or use of pupil be managed easily by proper radial, grid, hybrid, cross pattern. In
dilating instrument like malyugin coordination and minimizing the one prospective non randomised study,
ring can help. Some surgeons used wastage of time between two steps. phacoemulsification time and power have
OVD also, but its usefulness is not 7. Capsular Tears: The FLACS been evaluated and found that there was
proven. procedure give us supreme precision decreased mean cumulative dissipative
4. Management of Intraocular gas in size, shape and position of the energy and reduced endothelial cell loss
bubble: During the femtolaser capsulotomy. Though called a rhesix, by 25% with FSL16.
intraocular gas bubble formation it is not technically a continuous
within the tissue is problematic curvilinear capsulerhexis and is Refractive Outcomes- Various
issue, especially if the bubble formed in fact an advanced form of can studies have been done in past to
behind the lens nucleus in the opener capsulotomy. By virtue of the compare the refractive outcomes of
capsular bag. If this bubble is not multiple non contiguous perforations manual verses FSL surgery. Study done
removed properly it can increase and the few random spots delivered by Szigeti et al found that there was no
the intracapsular pressure and on either side of the intended path difference between the two groups in
ultimately can result in posterior of the laser beam, the capsulotomy terms of uncorrected and best corrected
capsular rupture and lens drop. To does have a propensity to radial near and distant visual acuities. In one
avoid this complication lens should tears. This has been elegantly studied study a cohort of 60 and 29 eyes has
be tapped with the blunt instrument and proven by Brendon Vote and been done operated with FLACS and
before starting phacoemulsification his colleagues in New Zealand. It is manual phacoemulsification respectively.
and shifting of gas bubble towards important for surgeons to be aware The results showed no difference in the
anterior chamber from behind of this complication and be prepared mean postoperative spherical equivalent
through lens equator should be to handle such problems during refraction between the two patient
ensured. surgery. groups17.
5. Incomplete capsulotomy: In-
complete capsulorhexis is not Clinical Outcomes Summary
unknown. Although advances/
updates in machines decreased In terms of anterior capsulotomy: This new femtosecond laser
its incidence14 but still there are Importance of precise anterior technology is better than manual phaco
chances of radial tear resulted from capsulotomy in lens centration and emulsification surgery by providing more
inadvertent pull in incomplete effective lens positioning which further accuracy, repeatability and consistency
capsulorhexis which can cause radial effect postoperative refractive error in results along with the option of
tear and further possibility of its has been extremely evaluated in past. customization of various parameters.
extension can complicate further Studies have shown that 1mm anterior While predictability, safety have been
surgery. To avoid this problem displacement of posterior chamber established, the cost factor still remains
surgeon should make sure that lens cause 1.25 D myopic shift15. Few a concern. Definitely large scale phase 3,
capsule is totally free from all sides studies have been done on circularity multicentric randomised control trials
and should not be pulled radially. of capsulorhexis where circularity was will be able to prove its efficacy along
Special care should be given to cases shown significantly better in FSL group with complications rate in comparison to
manual phacoemulsification.
References conventional phacoemulsification. J Refract
Surg 2012;28:540-4. 13. Friedman NJ, Palanker DV, Schuele G,
1. Mohan M. National Survey of Blindness-India. 8. Nagy ZZ, Ecsedy M, Kovacs I, et al. Macular
NPCB-WHO Report. New Delhi: Ministry of morphology assessed by optical coherence Andersen D, Marcellino G, Seibel BS et al.
Health and Family Welfare, Government of tomography image segmentation after
India; 1989. femtosecond laser-assisted and standard Femtosecond laser capsulotomy. J Cataract
cataract surgery. J Cataract Refract Surg
2. Mohan M. Collaborative Study on Blindness 2012;38:941-6. Refract Surg 2011;37:1189–98.
(1971-1974): A report. New Delhi, India: 9. Friedman NJ, Palanker DV, Schuele G, et al.
Indian Council of Medical Research;1987. Femtosecond laser capsulotomy. J Cataract 14. Palanker D, Blumenkranz MS, Andersen
pp.1–65. Refract Surg 2011;37:1189-98.
10. Hernandez-Verdejo JL, Teus MA, Roman JM, D, Wiltberger M, Marcellino G, Gooding P
3. Jose R, Bachani D. Performance of cataract Bolivar G. Porcine model to compare real-
surgery between April 2002 and March 2003. time intraocular pressure during LASIK et al. Femtosecond laser-assisted cataract
NPCB-India. 2003;2:2. with a mechanical microkeratome and
femtosecond laser. Invest Ophthalmol Vis Sci surgery with integrated optical coherence
4. Krasnov MM. Laser-phakopuncture in the 2007;48:68-72.
treatment of soft cataracts. Br J Ophthalmol 11. Chaurasia SS, Luengo Gimeno F, Tan K, Yu tomography. Sci Trans Med 2010;2:58-85.
1975;59:96-8. S, Tan DT, Beuerman RW et al. In vivo real-
time intraocular pressure variations during 15. Laksminarayanan V, Enoch JM, Raasch
5. Reggiano-Mello G, Krueger RR. Comparison LASIK flap creation. Invest Ophthalmol Vis
of commercially available femtosecond lasers Sci 2010;51:4641–45. T, Crawford B, Nygaard RW. Refractive
in refractive surgery. Expert Rev Ophthalmol 12. Ecsedy M, Mihaltz K, Kovacs I, Takacs I,
2011;6:55–65. Filkorn T, Nagy ZZ. Effect of femtosecond changes induced by intraocular lens tilt and
laser cataract surgery on the macula. J Refract
6. Kullman G, Pineda R. Alternative applications Surg 2011;27:717–22. longitudinal displacement. Arch Ophthalmol
of the femtosecond laser in ophthalmology.
Semin Ophthalmol 2010;25(5–6):256–64. 1986;104:90–92.
7. Filkorn T, Kovacs I, Takacs A, et al. Comparison 16. Kranitz K, Mihaltz K, Sandor GL, Takacs A,
of IOL power calculation and refractive
outcomes after laser refractive cataract Knorz MC, Nagy ZZ. Intraocular lens tilt
surgery with a femtosecond laser versus and decentration measured by Scheimpflug
camera following manual or femtosecond
laser-created continuous circular
capsulotomy. J Refract Surg 2012;28:259–63.
17. Roberts TV, Lawless M, Bali SJ, Hodge S,
Sutton G. Surgical outcomes and safety
of femtosecond laser cataract surgery: a
prospective study of 1500 consecutive cases.
Ophthalmology 2013;120:227-33.
Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
12 DOS Times - July-August 2015
cornea
Corneal Collagen Cross Linking –
Current Perspectives
Surabhi Dutt, Umang Mathur
Corneal collagen cross linking (CXL) is an TRANSEPITHELIAL CROSSLINKING
upcoming and safe treatment modality for corneal
ectatic disorders. It is a technique which uses Trans-epithelial CXL was introduced to prevent the adverse
ultraviolet(UV) light and a photosensitizer to form events associated with epithelial debridement (postoperative
strong chemical bonds with adjacent collagen pain, infectious keratitis, stromal haze) as well as for its possible
fibrils. The goal is to halt progression. role in treating thinner corneas. In this method, various chemical
Human studies with CXL began in 2003 in Dresden, and enhancers such as benzalkonium chloride (BAK), trometamol,
early results were promising. The initial pilot study enrolled and ethylenediaminetetraacetic acid (EDTA)7 as well as the use
16 patients with rapidly progressive keratoconus. The trial of hypotonic riboflavin solution have been used to enhance
successfully halted progression in all the patients. The standard riboflavin’s penetration8. Transepithelial CXL was performed
treatment of Dresden protocol uses 0.1% Riboflavin in 20% by applying the enhanced riboflavin solution (riboflavin
Dextran drops on a de-epithelised cornea every two minutes 0.1%, dextran T500 with trometamol [Tris-hydroxymethyl
for 30 minutes followed by UV A irradiation at 3Mw/cm 2 for aminomethane] and EDTA [ethylenediaminetetraacetic] salt
30 minutes at wavelength of 370nm¹. on the intact corneal epithelium for 30 minutes followed by
Indications2-4: mild to moderate keratoconus, post refractive irradiation with UV A (370 nm at 3 mW/m²) for 30 minutes.
ectasia, pellucid marginal degeneration, pseudophakic bullous
keratopathy, infective keratitis, pathological myopia include There are a few studies which show promising results with
and sclera CXL for glaucoma. this method for thin corneas, with significant improvements
In the recent past, there have been many advances with in uncorrected and corrected visual acuity7. The control eyes,
respect to CXL, either alone or in combination with various showed a general trend towards worsening of these parameters.
refractive surgical techniques. The main aim to expand the
indications for CXL is to, improve patient comfort , improve In contrast, Caporossi et al8, demonstrated a gradual shift
functional vision along with providing corneal stability. towards baseline preoperative values. The maximum K value
worsened at 24 months. Pachymetry showed a progressive,
statistically significant decrease at 24 months.
CROSSLINKING FOR POST REFRACTIVE ECTASIA
CROSSLINKING IN THIN CORNEAS One of the most troublesome complications after laser
Corneas with a stromal thickness of less than 400 μm are in situ keratomileusis (LASIK) is progressive iatrogenic
excluded from the standard treatment so as to avoid damaging keratectasia, which may be seen several months after surgery.
the endothelial cells with the UV radiation. Various methods The actual incidence of ectasia is unknown, it has been
of CXL have been developed to estimated to be 0.04%–0.6%9.
treat this patient population.
Riboflavin – UVA corneal collagen cross Majority of the studies
Studies have been done in have shown promising results
patients with corneal thickness
linking is a therapeutic modality that with CXL for post refractive
ectasia.
less than 400 μm with the use of may halt the progression of the ectatic
hypo-osmolar Riboflavin 0.1% The studies conclude
in 20% dextran solution. The
process in keratoconus and post - that ectasia after LASIK and
photorefractive keratomileusis
method of instillation is similar keratorefractive surgery ectasias.
(PRK) is arrested by CXL with
to standard CXL protocol. stabilization or improvement
A study was conducted by of CDVA and Kmax. Also the
Kymionis GD et al5 patients underwent standard CXL procedure procedure is not associated with endothelial cell loss. Studies
with corneal thickness of less than 400 μm. Uncorrected show stabilization of UDVA and BCVA and halt the progression
distance visual acuity (UDVA) and corrected distance visual of ectasia and need for surgical intervention10,11.
acuity (CDVA) improved. However there was a significant A study conducted in Greece12 included 22 patients (32
decrease in endothelial cell density (ECD). The study concluded eyes) with corneal ectasia occurring one to four years after
that standard CXL in thin corneas (< 400 μm) is unsafe. LASIK. They underwent trans-epithelial topography guided
The studies reported stabilization of ectasia in terms PRK immediately followed by standard CXL (3 mW/cm2). The
of mean keratometry value and best corrected visual acuity average residual stromal thickness was 285 μm post LASIK.
(BCVA)5,6. No intra-operative or post-operative complications Twenty-seven of 32 eyes had an improvement in UDVA and had
were observed.
CDVA of 20/45 or better (2.2 logMAR) at last follow-up. Mean
refractive error decreased by more than 2.50 D in 27 of 32 eyes.
www. dos-times.org 13
cornea
This study postulated that trans- achieve an important goal: to stabilize the follow-up is necessary to confirm the
epithelial PRK may facilitate riboflavin disorder and at the same time to assist in stability of the results19.
penetration into corneal stroma, resulting achieving functional vision.
in more effective CXL. Performing both CXL FOR KERATITIS
procedures at the same time appears to The prerequisites for the combined
minimize the potential superficial stromal procedure are: Preoperative pachymetry Riboflavin and UVA (280-370 nm)
scarring resulting from topography more than 500 microns, ablation should inter-action inactivates nucleic acids of
guided PRK. not exceed 50 microns of stroma, treat the microbes by direct electron transfer,
less than one dioptre myopia and less production of singlet oxygen, and
CROSSLINKING COMIBINED WITH than two dioptre astigmatism. generation of hydrogen peroxide with
INTRACORNEAL RING SEGMENTS formation of hydroxyl radicals. This is the
(ICRS) Studies have demonstrated rationale for the use of CXL in microbial
that the simultaneous approach of keratitis cases. The bactericidal and
There has been a lot of speculation photorefractive keratectomy (PRK) with stromal strengthening properties of cross
relating to whether sequential CXL and CXL for management of keratoconus linking make it a very attractive option for
insertion of an intra stromal corneal offers improvement in UDVA, BCVA and treating bacterial keratitis.
ring segment (ICRS) is better or would topographic parameters, even if the
same day combined treatment be more surgical goal was not a refractive end Various studies comprising of
effective? Alternatively, could ICRS point to begin with16,17. small series of patients have shown a
implantation be performed first and CXL beneficial role of CXL in refractory cases
later? This combined treatment seems to of keratitis20,21.
be more appropriate for patients with
The first comparative study of the two early keratoconus staging, because in It is a promising option for intractable
treatments in patients with keratoconus more advanced cases, thinning of the cases of keratitis as an adjuvant treatment
was reported by Coskunseven and cornea could limit the possibility of tissue to conventional therapeutic modalities
associates. They concluded that removal by topography-guided PRK. and may help in deferring emergency
implantation of ICRS followed by CXL keratoplasty. However, this modality of
resulted in greater improvement than CXL IN PELLUCID MARGINAL treatment remains to be validated in
CXL followed by ICRS implantation13. DEGENERATION (PMD) detail in future studies.
Most studies that combined the two One case report describes a patient Accelerated CXL
techniques, performed ICRS followed by with bilateral PMD, who underwent
CXL either same day or sequentially14,15. CXL unilaterally, on the side with more Recently the trend is shifting
profound ectasia. The treated eye was towards aiming at shorter duration of
Results of various studies show no examined during the first year after CXL treatment.
difference in delayed ICRS insertion after treatment. Reduced corneal astigmatism
CXL, however presently not enough clinical and improved visual acuity were The accelerated CXL device (KXL™)
evidence is available supporting one detected at three months and remained significantly reduces the treatment time
sequence over the other. Related studies stable through the 12-month interval. from one hour to a few minutes, while
show large variability in their methods The endothelial cell count and corneal maintaining the same treatment dose as
(eg, standard or transepithelial CXL, thickness remained unchanged from the in conventional CXL. As an alternative
follow-up, model of inlay and its insertion preoperative assessment to 12 months, to riboflavin formulations containing
depth, mechanical or femtosecond laser confirming the safety of CXL18. dextran, the KXL uses riboflavin 0.1% in
tunnel creation, mean interval between hydroxypropyl methylcellulose (Vibex
treatments and the results displayed), A case report describes a patient Rapid™, Avedro, Inc.).
characterizing uncertainty regarding the having simultaneous PRK and CXL for
optimal treatment sequence. the treatment of progressive PMD in The initial procedure is similar
both eyes. No intra operative or early to conventional CXL of epithelial
Stromal haze was initially noted postoperative complications occurred. debridement. Vibex is then administered
after CXL in most of the studies. The haze Twelve months postoperatively, the topically for 10 minutes. The cornea
was more prominent along the channels uncorrected visual acuity was assessed is then exposed to 365 nm UVA light
of the ICRS. The haze regressed with the at 20/40 in both eyes compared with with the CXL system for three minutes
use of local steroid treatment. counting fingers preoperatively. The at an irradiance level of 30 mW/cm2
corrected visual acuity also improved (accelerated CXL).
CROSSLINKING WITH from 20/50 and 20/63 to 20/25 and
PHOTOREFRACTIVE KERATECTOMY 20/32 in the right eye and left eye, There are very few large series studies
(PRK) respectively. Corneal topography revealed as this is an upcoming advancement.
a significant improvement in both eyes. However, most of the studies have shown
CXL combined with topography- Despite the encouraging results, longer that accelerated CXL is equally efficacious
guided PRK has been developed to as compared to conventional CXL in
keratoconus patients22.
Cornea Services & Refractive Services, Dr. Shroff ’s Charity Eye Hospital, Daryaganj, New Delhi, India
Dr. Surabhi Dutt MS Dr. Umang Mathur MS
14 DOS Times - July-August 2015
cornea
LASIK Xtra Riboflavin is a key component of the 5. Kymionis G.D., Portaliou D.M. ,
photochemical cross linking treatment
Kanellopoulos and colleagues as it increases corneal absorption of UVA Diakonis V F, Kounis G.A., et al.
in 2009 introduced the concept of and thereby protects the deeper ocular
simultaneous collagen cross linking with structures, especially the endothelium, Corneal collagen cross-linking with
conventional LASIK procedure. This has from UVA damage. riboflavin and UV-A irradiation in
now been termed as LASIK Xtra. The
procedure is indicated for individuals Thus far, clinical and laboratory patients with thin corneas. Am J
who are at higher risk of post LASIK studies of corneal collagen cross linking
ectasia or regression. have advocated epithelial debridement Ophthalmol 2012;153:24-28.
for adequate penetration of riboflavin
The patients included in this high into the corneal stroma. 6. Raiskup F, Spoerl E. Corneal
risk group are:
• High myopes However, to reduce the early crosslinking with hypo-osmolar
• Borderline corneal pachymetry postoperative discomfort experienced Riboflavin solution in thin
• Asymmetry in topography by the patient (as a result of epithelial
• Hyperopes removal), some studies have performed keratoconic corneas. Am J
• Family history of keratoconus the procedure with the epithelium intact.
• History of chronic ocular allergies Ophthalmol 2011;1 :28-32.
There are many cases of keratoconus
Procedure for LASIK Xtra: A variation and post-LASIK ectasia with corneal 7. Filippello M, Stagni E, O’Brart D.
of Riboflavin formulation is used which stromal thickness less than 400 μm,
comes by the name Vibex Xtra. This is in these cases, the existing standard Transepithelial corneal collagen
0.1%Riboflavin diluted in saline instead CXL protocol is contraindicated. Thus
of Dextran. After lifting the LASIK flap, an alternative treatment protocol has crosslinking: bilateral study. J
the flap is folded over itself in order been advocated in thin corneas using
to prevent absorption of Riboflavin by hypoosmolar riboflavin solution. The Cataract Refract Surg. 2012; 38:283-
the flap. A single drop of Vibex Xtra is use of hypo-osmolar riboflavin solution
placed over the exposed stromal bed and remains a very promising alternative for 291.
carefully spread. Soaking of Riboflavin is the treatment of thin corneas.
continued for one minute and then the 8. Caporossi A , Mazzotta C, Paradiso
flap is repositioned. Remaining Riboflavin Simultaneous topography-guided
is thoroughly washed from the stromal PRK and CXL appears to be effective in the L, Baiocchi S, et al. Transepithelial
bed. Next high fluence cross linking is rehabilitation of corneal ectasia. There
carried out at irradiation of 30 Mw/cm2 have been potentially promising results corneal collagen crosslinking for
for 80 seconds. with same-day, simultaneous topography-
guided PRK and CXL as a therapeutic progressive keratoconus: 24-month
Accelerated CXL has also shown very intervention in highly irregular corneas.
promising results in combination with clinical results. J Cataract Refract
LASIK23,24. Collagen cross linking has proven its
worth in the treatment of keratoconus Surg 2013; 39:1157–63.
CROSSLINKING IN CHILDREN and post-LASIK ectasia. Possible future
applications, related to, trans-epithelial 9. Binder PS. Analysis of ectasia after
Though keratoconus is most CXL, accelerated CXL, treatment of
frequently diagnosed after adolescence, corneal infections, PMD, paediatric laser in situ keratomileusis: risk
the corneal ectasia process starts at a keratoconus and LASIK Xtra still need
much younger age. Due to the success large prospective randomized clinical factors. J Cataract Refract Surg. 2007;
of CXL in adult keratoconus patients, trials with longer follow-ups to be
CXL studies in paediatric age group have considered as standardised treatment 33:1530–38.
been undertaken with the aim to prevent modalities.
progression25. 10. Salgado JP, Khorammia R, Lohmann
REFERENCES
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shown very promising results. Trans- 1. Wollensak G, Spoerl E, Seiler T.
epithelial CXL has also been attempted Riboflavin/ultraviolet-a-induced Corneal collagen crosslinking in post-
with varying results. Some studies have collagen crosslinking for the
noted keratometric progression at treatment of keratoconus. Am J LASIK keratectasia. Br J Ophthalmol.
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4. Aylin K. Corneal crosslinking for
different corneal diseases. J Cataract Management of Corneal Ectasia
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day, Topography guided Partial
Transepithelial PRK and Collagen
Cross-linking: The Athens Protocol. J
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13. Coskunseven E, Jankov MR II, Hafezi
F, Atun S, Arslan E, Kymionis GD.
Effect of treatment sequence in
combined intrastromal corneal rings
and corneal collagen crosslinking for
keratoconus. J Cataract Refract Surg
2009; 35:2084–2091.
14. Sonia N. Yeung et al. Transepithelial
phototherapeutic keratectomy
combined with implantation of
a single inferior intrastromal
corneal ring segment and collagen
crosslinking in keratoconus. J
Cataract Refract Surg 2013; 39:1152–
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16. Kymionis GD, Kontadakis GA,
Kounis GA, et al. Simultaneous
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17. Kanellopoulos AJ. Comparison
of sequential vs same-day
simultaneous collagen cross-linking
and topography-guided PRK for
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treatment of keratoconus. J Refract cross-linking: a case report. Eur J 24. Kanellopoulos AJ. Long term safety
Ophthalmol. 2009;19:295-7. and efficacy of prophylactic higher
Surg 2009; 25:S812–S818. 21. Price MO, Tenkman LR, Schrier A, fluence collagen crosslinking in
Fairchild KM, Trokel SL, Price FW. high myopic laser assistedin situ
18. Spadea L. Corneal collagen cross- Photoactivated riboflavin treatment
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22. Minoru Tomita, Mariko Mita,
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versus conventional corneal collagen keratoconus and efficacy of pediatric
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19. Kymionis GD, Karavitaki AE, Kounis 23. Celik HU et al. Accelerated corneal children and adolescents. Refract
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20. Micelli F, Leozappa M, Lorusso M. et
al. Escherichia coli keratitis treated
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Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
DOS Monthly Clinical Meeting 2015 - 16
Date Institute/Hospital to host DOS
July 26, 2015 Dr. Rajendra Prasad Centre for Ophthalmic Sciences
August 30, 2015 Army Research and Referral Hospital
September 27, 2015 Dr. Shroff Charity Eye Hospital
October 25, 2015 Ram Manohar Lohia Hospital
November 29, 2015 Safdarjung Hospital
December 27, 2015 Deen Dayal Upadhyay Hospital
January 31, 2016 Centre for Sight
February 21, 2016 Bharti Eye Hospital
March 27, 2016 Guru Nanak Eye Centre
16 DOS Times - July-August 2015
Refractive Surgery
CXL Plus - Corneal Collagen Cross-Linking
Combined With Refractive Surgery
Dr. Ramendra Bakshi MS, FRCS, FMRF PRK. Moreover, removal of the crosslinked corneal tissue by the
Cornea Cataract and Refractive Surgery PRK procedure could decrease the stiffening effects of the CXL
Eye 7 Group of Eye Hospitals, New Delhi treatment.
Since a decade, collagen cross linking (CXL) has been LASER IN SITU KERATOMILEUSIS
used for the treatment of patients with disorders
such as keratoconus, corneal ectasia after refractive LASIK is the most common form of refractive surgery, but,
surgery, bullous keratopathy and infectious despite important technical advances, some limitations remain.
keratitis, with great promise. It is thought that the Of specific concern are ectasia and refractive regression.
combination of CXL with refractive surgery might
improve visual outcomes in addition to providing corneal REGRESSION
stabilization. This combined surgery has been termed ‘CXL
plus. The objective of this article is to describe the various The correction achieved with LASIK is not always stable,
combinations by which CXL can be combined with refractive and in some cases refractive regression can occur. Studies
surgery so that patients with corneal ecstatic disorders can have shown that the risk of regression is between 5.5% and
benefit from it1. 27.7%. In a study of 615 eyes, Chen et al found that multiple
factors influenced regression, including preoperative manifest
PHOTOREFRACTIVE KERATECTOMY refraction spherical equivalent (MRSE), mean preoperative
central corneal curvature, optic zone size, undercorrection, and
Simultaneous Combination (PRK+CXL) in Keratoconus age4.
In 2009, Kymionis and colleague demonstrated customized
topography-guided PRK followed by immediate CXL in 12 The combination of LASIK and corneal collagen
patients with keratoconus, with a mean follow-up of 10.69 crosslinking (CXL) may be able to stabilize LASIK results over
months. They reported promising results, with the offer of a longer period.
functional vision2. In the same year, Kanellopoulos evaluated
the effect of different sequences and timing on the safety ECTASIA
and efficacy of combined surgery in a prospective study that
included a total of 325 eyes with keratoconus. The first group Post-LASIK ectasia can develop in as little as 1 week
(127 eyes) underwent CXL with subsequent topography-guided or as long as a few years after the initial procedure. When it
PRK performed 6 months later (sequential group), while the manifests, patients typically present with increased myopia and
second group (198 eyes) underwent PRK and CXL in a combined astigmatism, loss of distance UCVA, and, often, loss of distance
procedure on the same day (simultaneous group). Statistically, BCVA. Many treatment options are available, but in some cases
the simultaneous group performed better on all parameters a corneal transplant is still necessary.
evaluated, including UCVA, BSCVA, spherical equivalent (SE)
refraction and keratometry and less corneal haze. The author Post-LASIK ectasia is relatively rare. In the literature, the
named the technique of CXL performed immediately after incidence is about 0.04% to 0.6%. However, accurate clinical
topography-guided PRK as the ‘Athens Protocol’3. studies on this topic are lacking.
Here, partial topography guided PRK is done to normalize
the cornea, reducing irregular astigmatism while treating part Preventing ectasia is naturally more desirable than having
of the refractive error. The effective optical zone diameter is to treat it, and CXL has emerged as a promising new technique
reduced to 5.5mm to minimize the amount of tissue ablated. aimed at slowing or stopping its progression. Clinical results
Approximately 70 percent of the cylinder and upto 70 percent indicate that BCVA and corneal curvature in patients with
sphere is planned to be treated in order to ablate not more than keratoconus improved or remained stable after CXL (maximum
50 microns of the tissue. Accelerated CXL can be combined with follow-up, 6 years).
PRK to reduce the overall treatment time.
COMBINATION TREATMENTS
Disadvantages of the sequential procedure (CXL
followed by PRK) CXL plus LASIK: CXL is used to improve refractive
correction after LASIK in healthy eyes. The function of CXL is to
Crosslinked corneas may have a different ablation rate stabilize the cornea, which may have become destabilized as a
from normal corneas, which could lead to unpredictable PRK result of the creation of the corneal flap.
results. There is increased possibility of haze formation after
Corneal biochemical response has been associated with the
pathophysiology of regression after LASIK; therefore, modifying
The combination of CXL with refractive
surgery might improve visual outcomes
in addition to providing corneal
stabilization. This combined surgery has
been termed ‘CXL plus
www. dos-times.org 17
Refractive Surgery
Figure 1: Pre and post treatement Pentacam maps of a patient with simultaneous CXL with INTACS
the biochemical properties of the Procedure: After the refractive Indications: Patients less than 30,
cornea may result in positive treatment myopia over 6D, astigmatism over 1D, if
outcomes. When CXL is combined with correction has been made in a standard
LASIK, the refractive correction should Lasik procedure, Vibex Xtra (Riboflavin there is a difference in the amount of the
remain stable over time, and post-LASIK 0.25% with saline) is applied to the
ectasia may be prevented. Moreover, exposed stroma for 60 sec and the flap astigmatism between the two eyes of over
due to the increased stability of the is replaced. UVA illumination from
postoperative result, patients who would 0.5D, Hyperopic Lasik, borderline corneal
normally be excluded from LASIK— Accelerated CXL 30mw/cm2 is then
those with a higher risk of ectasia—can thickness, patients with family history of
be treated. Although current results are applied through the intact epithelium for keratoconus5-6.
encouraging, this concept is still in a
clinical investigational phase. 80 sec. Total energy is kept at 2.5 J/cm2 Kanellopoulos AJ. Studied Long
term safety and efficacy follow-up of
instead of the conventional 5.4 J/cm2 prophylactic higher fluence collagen
Replacing the flap back helps reduce cross-linking in high myopic laser-
stromal exposure time and risk of flap assisted in situ keratomileusis in 43 eyes.
dehydration.
Follow up was 3.5 years. They concluded
18 DOS Times - July-August 2015
Refractive Surgery
that prophylactic CXL for high risk lasik
was a safe and effective adjunctive
treatment for regression and possible
ectasia5.
Possible complications: Similar
to a standalone LASIK procedure, LASIK
plus CXL also carries the risk of flap-
related problems and epithelial ingrowth
(0.92%). Furthermore, the flap is more
difficult to relift after the combined
procedure than after LASIK alone.
There is a higher risk of DLK with lasik
Xtra but with the new riboflavin with
saline the incidence of DLK has dropped
significantly.
INTRACORNEAL RING SEGMENT Figure 2: Slit Lamp image of post operative INTACS+CXL
IMPLANTATION
Kılic et al in their series of 131 of the corneal epithelium have been
ICRS along with collagen cross eyes with a mean follow up of 7 different, the combined methods have
linking has opened new vistas in the all delivered promising results and
treatment of keratoconus and corneal months evaluated the effectiveness of additional effects over a single operation.
ectasia. While cross linking stops the intracorneal riboflavin injection for Further controlled research with long
progression of the ectasia and reverses combined collagen crosslinking (CXL) and follow-ups is required.
it to some extent, ICRS flatten or
normalize the corneal shape. Combining (ICRS) implantation. The mean manifest INTRAOCULAR LENS
both the modalities together has a Posterior Chamber Intraocular Lens
synergistic action and can be performed spherical refraction decreased from -3.87
simulatneously or sequentially. Although Fadlallah A et al studied the results
each treatment step improves the cornea, +/-4.55 diopters (D) to -1.25 +/- 2.31 D, of two-step CXL and toric implantable
a stiffer cornea that has been treated by Collamer lens implantation procedure
CXL decreases the flattening effect of ICRS the mean manifest cylinder improved at an interval of 6 months in 16 eyes of
implantation, thus restricting its effect 10 patients with keratoconus seemed
and decreasing the maximum flattening from -3.89 +/- 1.97 D to -2.27 +/- 2.18 D, satisfactory. Mean spherical equivalent
potential (Figures 1,2). decreased from -7.24 ± 3.53 to -0.89
and the mean K reading improved from ± 0.76 D (P = .001) and mean cylinder
Coskunseven et al have compared decreased from 2.64 ± 1.28 to 1.16 ±
the effect of treatment sequence for ICRS 50.50 +/- 5.26 D to 46.03 +/- 4.51 D (all 0.64 D (P = .001). J Refract Surg. 2013
and CXL. In this prospective comparative Feb;29(2):84-911.
randomized consecutive study, CXL was P<.05). They concluded that the combined
followed by ICRS implantation (Group Sequential CXL followed by Toric
1) or ICRS implantation was followed by procedure was effective in keratoconic ICL implantation may be a possible
CXL (Group 2). They concluded that to eyes. Intracorneal riboflavin injection alternative surgical option for the visual
achieve the maximum overall effect, ICRS into the tunnel was safe and may provide rehabilitation of high myopic astigmatism
implantation should be performed first in keratoconus patients with rigid gas
or simultaneously so the segments can more penetration without epithelial permeable contact lens intolerance and
reshape the cornea without restriction. removal. An intrastromal riboflavin reflex in patients who wish to defer a corneal
The CXL treatment then can be applied to was observed around the corneal channel transplant. A longer follow-up period is
further flatten the cornea and to stabilize needed to monitor for complications such
corneal biomechanics7. only and during the follow-up there as cataract formation and pigmentary
dispersion11-12.
Chan et al did a retrospective was stromal whitening at the location
nonrandomized comparative case series MULTI-OPERATION
comprising of 12 eyes of 9 patients who surrounding the segment. Limited and Intacs+Photorefractive
had inferior-segment Intacs placement localized riboflavin penetration around Keratectomy + Collagen Cross-
without CXL (Intacs-only group) and 13 the ICRS may increase the effect of the Linking
eyes of 12 patients who had inferior-
segment Intacs placement combined with segments and produce less corneal haze Two different-scale clinical trials
CXL (Intacs with CXL group). The addition have performed Intacs implantations
of CXL to the Intacs procedure resulted in in the central cornea, which may affect
greater keratoconus improvements than
Intacs insertion alone. CXL augmented visual acuity. It has also be hypothesised
the reversal effect of Intacs on the that the newly dissected femtosecond
keratoconus cone as shown by the greater corneal channel may result in more
changes in cylinder, K steep, K average, in pooling of riboflavin with resultant
the Intacs with CXL group8. exaggerated flattening effect of CXL. This
is in contrast to the healed channel that
was potentially closed tightly on the ring9-
10.
Various surgical procedures
involving CXL combined with Intacs
insertion have been investigated.
Although the sequences and involvement
www. dos-times.org 19
Refractive Surgery
followed by same-day PRK and CXL in
patients with keratoconus. UDVA, CDVA,
and sphere and cylinder refractive
measurements all significantly improved
after this multi-operation combination,
with most eyes gaining two lines of
CDVA or more. A study of simultaneous
wavefront-guided PRK and CXL at
least 6 months after previous Intacs
implantation found that it satisfactorily
changed the UDVA, CDVA and central K
values13-15 (Figure 3).
SUMMARY Figure 3: Topography map of eye with Intracorneal Rings +PRK+CXL15.
The combination of CXL with selected for patients for mild refraction moderate to severe ametropia. Further
different refractive surgeries perfectly errors and a phakic intraocular lens was controlled trials may be helpful in making
meets the needs of keratectasia patients considered suitable for patients with such decisions.
in terms of halting disease progression
and improving visual function. It can
sometimes be difficult to choose the most
suitable refractive operation protocol.
In a study by Fadlallah and colleagues,
Intacs implantation was used for patients
with poor best corrected visual acuity,
while topography-guided PRK was
References 6. Kanellopoulos AJ, Kahn J. Topography- visual outcome of Visian toric ICL
guided hyperopic LASIK with and implantation after corneal collagen
1. Na Li, Xiu-Jun Peng, and Zheng-Jun without high irradiance collagen cross- cross-linking in keratoconus. J
Fan. Progress of corneal collagen linking: initial comparative clinical Refract Surg. 2013;29:84–89.
cross-linking combined with refractive findings in a contralateral eye study of 12. Kymionis GD, Grentzelos MA,
surgery. Int J Ophthalmol. 2014;7:157– 34 consecutive patients. J Refract Surg. Karavitaki AE, Zotta P, et al. Combined
62. 2012;28:837–40. corneal collagen cross-linking and
posterior chamber toric implantable
2. Kymionis GD, Kontadakis GA, Kounis 7. Coskunseven E, Jankov MR, 2nd, Hafezi collamer lens implantation for
GA, Portaliou DM, Karavitaki AE, F, Atun S, Arslan E, Kymionis GD. Effect keratoconus.Ophthalmic Surg Lasers
Magarakis M, Yoo S, Pallikaris IG. of treatment sequence in combined Imaging. 2011;17:42 Online: e22–5.
Simultaneous topography-guided PRK intrastromal corneal rings and corneal 13. Al-Tuwairqi W, Sinjab MM.
followed by corneal collagen cross- collagen crosslinking for keratoconus. J Intracorneal ring segments
linking for keratoconus. J Refract Surg. Cataract Refract Surg. 2009;35:2084– implantation followed by same-day
2009;25:807–11. 91. topography-guided PRK and corneal
collagen CXL in low to moderate
3. Kanellopoulos AJ, Binder PS. 8. Chan CC Effect of inferior-segment keratoconus. J Refract Surg.
Management of corneal ectasia Intacs with and without C3-R on 2013;29:59–63.
after LASIK with combined, same- keratoconus. J Cataract Refract Surg. 14. Iovieno A, Légaré ME, Rootman
day, topography-guided partial 2007;33:75-80. DB, Yeung SN, Kim P, Rootman
transepithelial PRK and collagen cross- DS. Intracorneal ring segments
linking: the athens protocol. J Refract 9. Kilic A, Kamburoglu G, Akıncı A. implantation followed by same-
Surg.2011;27:323–31. Riboflavin injection into the corneal day photorefractive keratectomy
channel for combined collagen and corneal collagen cross-linking
4. Liu Z, Li Y, Cheng Z, Zhou F, Jiang H, Li crosslinking and intrastromal corneal in keratoconus. J Refract Surg.
J. Seven-year follow-up of LASIK for ring segment implantation. J Cataract 2011;27:915–18.
moderate to severe myopia. J Refract Refract Surg. 2012;38:878-83. 15. Dominique Pietrini et al. Topography
Surg. 2008;24:935–40. guided customized PRK combined
10. El-Raggal TM. Sequential versus with simultaneous CXL in patients
5. Kanellopoulos AJ. Long-term safety concurrent KERARINGS insertion with previously implanted ICRS
and efficacy follow-up of prophylactic and corneal collagen cross-linking for progressive keratoconus.
higher fluence collagen cross-linking for keratoconus. Br J Ophthalmol. Mediphacos user meet 2013.
in high myopic laser-assisted in situ 2011;95:37–41.
keratomileusis. Clin Ophthalmol.
2012;6:1125–30. 11. Fadlallah A, Dirani A, El Rami H,
Cherfane G, Jarade E. Safety and
Financial Interest: The author does not have any financial interest in any procedure/product mentioned in this manuscript.
20 DOS Times - July-August 2015
Refractive Surgery
Small Incision Lenticule Extraction :
The Future of Refractive Surgery
Gitansha Sachdev, Mahipal S. Sachdev, Ritika Sachdev, Hemlata Gupta
The most recent development in the field of
keratolenticular refractive procedures
Small Incision Lenticule Extraction (SMILE) is There are 3 discrete intraprocedural phases involved in
the most recent development in the field of SMILE.
keratolenticular refractive procedures1. Using the
femtosecond laser four sequential photoablative Initial docking with precise centration
incisions are used to create an intrastromal lenticule • A joystick attached to the movable bed is used to align
and a corneal incision that extends to the anterior
surface of the lenticule. The lenticule can then be extracted the patient’s eye to the curved contact glass interface
from within the corneal stroma, either by creating and lifting a (Figure 1) during the laser procedure, and repositioned
hinged flap similar to LASIK (Femtosecond Lenticule Extraction under the integrated surgical microscope during the phase
or FLEx) or by extricating it using a small incision in the cornea of surgical manipulation.
(SMILE). • A proper head positioned is achieved by tilting the patient’s
SMILE has become a preferred alternative to LASIK for head medially to avoid nasal contact with the cone of the
myopic correction within Europe and Asia2-3. It is currently contact glass interface.
awaiting U.S. Food and Drug Administration approval pending • The patient is asked to focus on the blinking light and
results in ongoing clinical trials. maintain fixation. Precise centration should be verified
before corneal contact with the treatment applanation
SELECTION CRITERIA interface.
• Age – The patient should be older than 18 years of age
• Refractive error - Myopic error of upto -10 D spherical Verification and maintenance of suction until all
femtosecond passes are complete
equivalent , with or without an astigmatism of upto -6
D and a stable refraction for over a year. ReLEx SMILE is Following proper centration and adequate placement of
currently not available for hyperopic correction. the contact glass on the patient’s eye, suction is initiated to hold
• Corneal topography - to rule out forme fruste keratoconus, the cornea against the contact glass interface.
pellucid marginal degeneration and posterior keratoconus.
• Pachymetry – A minimal coneal thickness of 475 to 500 The various tissue disruption planes (Figure 2 & 3) created
microns and a residual stromal bed thickness of 250 to 275 by the laser are as follows:
microns, in accordance with precautionary measures for 1) Posterior lenticule surface (from periphery to centre)
decreasing the incidence of post LASIK ectasia.
• Ocular history – Contraindicated in patients with lenticular followed by transition zone at the edge of the refractive
changes, glaucoma or other pre existing ocular diseases. zone (for spherocylindrical correction).
Retinal breaks or holes if any should be treated prior to the 2) Vertical edge incision along the perimeter of the lenticule
procedure. 3) Anterior lenticule surface (from centre to periphery).
4) Peripheral corneal incision for lenticule access and
VISUMAX LASER SYSTEM extraction. The incision is generally created superiorly
or superotemporally to preserve the nasal and temporal
SMILE procedure is performed using the VisuMax nerve arcades 5 and to provide surgical convenience.
Femtosecond laser4. The VisuMax software calculates the
thickness of lenticule required for refractive correction and Figure 1: The innovative corneal interface concept
the femtosecond laser creates a refractive lenticule with a high
degree of precision. www. dos-times.org 21
PROCEDURE
The procedure is carried out under topical anaesthesia.
The patient’s eyes are painted and draped using all aseptic
precautions. A standard eye speculum is used to keep the eye
open.
Refractive Surgery
Figure 3: surgical steps: Femtolaser assisted (a): posterior tissue disruption plane or lenticule
cut. (b): anterior tissue disruption plane or flap cut. (c): Superior flap side cut incision. Manual.
(d): delineation of planes. (e): dissection of planes (f) lenticule removal.
Figure 2: Incision geometry of the small- the suction automatically turns off. The required in SMILE as compared to
incision lenticule extraction procedure. The patient’s eye is repositioned under the femtoassisted LASIK
lenticule cut. (1): is performed (the underside microscope (observation mode). The b) Loss of contact between glass
of the lenticule), followed by the lenticule side side cut incision is opened up using a interface and cornea due to sudden
cuts. (2): Next, the cap interface. (3): is created small sharp tipped instrument. A manual eye or head movement: Following
(the upper side of the lenticule), and finally a spatula is inserted to separate residual completion of posterior lenticular
2.0 to 3.0 mm small incision. (4): is created lenticular appendages, first within the surface the fixation target is obscured
superotemporally6. anterior lamellar plane and then within by the opaque bubble layer (OBL).
the posterior plane. Finally, a forceps is The patient should be cautioned and
The entire laser procedure takes used to extract the intrastromal lenticule. advised not to search for the fixation
around 23 seconds irrespective of the target (“green blinking light”) once it
refractive error to be corrected. COMPLICATIONS disappears.
Intraoperative complications10 c) Ocular factors include a small
Parameters used7-9: palpebral aperture, loose corneal
1. Minor epithelial abrasions at incision epithelium, excessive reflex tearing,
• Repetition rate: 500 kHz. site and poor fixation
• Pulse energy: 120 to 170 nJ. d) Fluid entry through suction ports
• Spot distance: 2 to 5 microns. 2. Small tears at the incision or compressive forces against
• Lenticule side cut angle: 70 degrees. 3. Difficulty in lenticule removal the contact glass resulting from
• Lenticule diameter: 5.75 to 7 mm. During attempted lenticule intraocular gas-bubble transposition.
• Cap diameter: 7 to 7.9 mm (typically The current recommendations for
delineation, incorrect tissue suction loss during each stage are as
0.5 to 1mm greater than lenticule plane identification can result follows12:
diameter). in primary separation of the Stage 1 (posterior lenticule cut
• Cap thickness: 100 to 140 microns. posterior lenticule surface, <10%), restart;
• Side cut circumferential length: 3 to 5 resulting in its adherence to the Stage 2 (posterior lenticule cut
mm. stromal surface of the cap. In >10%), switch to LASIK;
• Minimum lenticule side cut thickness: this situation, it is still possible Stage 3 (lenticule side cut), repeat
15 microns. to achieve lenticule separation, the lenticule side cut and decrease the
but it is more difficult. lenticule diameter by 0.2 to 0.4 mm;
Performing manual lenticule 4. Suction loss Stage 4 (anterior lenticule cut),
extraction repeat the anterior lenticule cut;
Predisposing factors11:
Following completion of the
femtosecond laser (treatment mode) a) Longer duration of suction
Centre For Sight, Safdarjung Enclave, New Delhi
Dr. Gitansha Sachdev MS, FICO Dr. Mahipal S. Sachdev MD Dr. Ritika Sachdev MS Dr. Hemlata Gupta MS, DNB
22 DOS Times - July-August 2015
Refractive Surgery
Stage 5 (anterior lenticule side cut), With femtosecond laser, the Following epithelial debridement
repeat the anterior lenticule side cut and peripheral loss of fluence is not a factor the lenticule is placed on the stromal bed
decrease the lenticule diameter by 0.2 to at all, and no compensation needs to such that the thickest area of the lenticule
0.4 mm be carried out. So the amount of tissue corresponds to the thinnest area of the
required per diopter of treatment is cone (Figure 4). An augmented stromal
Postoperative complications smaller than that required with an thickness of more than 400 microns
excimer laser which compensates for the is confirmed using intraoperative
1. Symptoms of dry eye may be peripheral energy loss. pachymetry. The thickness of the lenticule
observed postoperatively, however placed is determined by the refractive
the occurrence is less as compared Reduced amount of energy is error corrected. Remaining CXL is carried
to that with conventional LASIK13. applied on to the cornea. Moreover the out in a routine manner. At the end of
These symptoms are found more heat generated by an excimer laser is in the procedure the refractive lenticule is
commonly in preoperative chronic a relatively shorter period resulting in peeled and the stromal bed is washed
contact lens users. adverse effects on corneal healing. using balanced salt solution. A bandage
contact lens is placed which is removed
2. Unintended abandonment of Reduced number of corneal nerves is 3-5 days postoperatively.
residual intrastromal lenticule severed due to smaller flap diameter and
fragments 10 side cut incision, thereby reducing the Femtosecond laser intrastromal
incidence of postoperative dry eye. lenticular implantation for hyperopia
3. Epithelial ingrowth (FILI)
4. Microstriae No flap related complications
5. Interface inflammation The small side cut incision heals Cryopreserved stromal lenticules
6. Vertical gas breakthrough14, transient relatively faster causing less patient obtained following SMILE for myopic
discomfort. correction are placed in a femtosecond
light sensitivity syndrome15, or created intrastromal pocket for the
rainbow glare 16 are almost never ADDITIONAL USES OF SMILE treatment of hyperopia18.
seen LENTICULE
It may potentially be a safe and
ADVANTAGES OVER FEMTO-LASIK Tailored stromal expansion with effective alternative to excimer laser
Significantly shortened procedural refractive lenticule for crosslinking ablation for hyperopia because of the
the ultrathin cornea low risks of regression, haze, flap-related
time due to use of a single laser platform complications, postoperative dry eye and
instead of the 2-platform procedure Keratoconus is a non-inflammatory higher-order aberrations.
progressive ectasia of the cornea.
Photo disruptive mechanism in Traditional corneal collagen crosslinking LATEST ADVANCES : CIRCLE
SMILE, unlike ablative mechanism of (CXL) requires a minimal stromal SOFTWARE
excimer laser is independent of factors thickness of 400 microns. However
like corneal hydration, temperature, patients with advanced forms of A recent adaptation of small-incision
atmospheric humidity and depth of keratoconus often have thinner corneas, lenticule extraction software (Circle, Carl
stromal ablation. thus making the disease not amenable Zeiss Meditec AG) enables revision of the
to traditional CXL. We describe a new previously created cap by remodeling it
Increased refractive predictability and innovative method of increasing into a larger diameter flap (with hinge)
over excimer laser particularly for higher the stromal thickness by adding a followed by excimer laser ablation
refractive errors. refractive lenticule obtained from (Figure 5).
patients undergoing SMILE for myopic
Significantly fewer total higher correction17.
order abberations particularly spherical
abberation.
Figure 4: Augmentation of stromal thickness
by placement of lenticule over stromal bed
following epithelial debridement
www. dos-times.org 23
Refractive Surgery
Figure 5: A lamellar ring is created at the same depth as the existing SMILE incision allowing the conversion of the SMILE cap into a hinged flap. The
flap is then raised followed by excimer laser ablation.
References 7. Zhao J, Yao P, LiM et al. The the correction of myopia - Six Month
morphology of corneal cap and its Results. J Cataract Refract Surg. 2008;
1. Rupal Shah, Samir Shah, Hartmut relation to refractive out- comes in 34:1513-20.
Vogelsang. All-in-One Femtosecond femtosecond laser small incision 14. Seider M, Ide T, Kymionis G, et al.
Laser Refractive Surgery Tech lenticule extraction (SMILE) with Epithelial breakthrough during
Ophthalmology 2011; 9:114-21. anterior segment optical coherence Intralase flap creation for laser in
tomography observation. PLoS One situ keratomileusis. J Cataract Refract
2. Sekundo W, Kunert K, Blum M. Small 2013; 8:e70208. Surg. 2008; 34:859-63.
incision corneal refractive surgery 15. Stonecipher KG, Dishler J, Ignacio
using the small incision lenticule 8. Reinstein DZ, Archer TJ, Gobbe M. TS, et al. Transient lightsensitivity
extraction (SMILE) procedure for Accuracy and reproducibility of cap after femtosecond laser flap creation:
the correction of myopia and myopic thickness in small incision lenticule clinical findings and management. J
astigmatism: results of a 6 month extraction. J Refract Surg 2013; Cataract Refract Surg. 2006;32:91-
prospective study. Br J Ophthalmol 29:810–15. 94.
2011;95:335–39. 16. Bamba S, Karolinne R, Ramos-
9. Ozgurhan EB, Agca A, Bozkurt E et Esteban J, et al. Incidence of
3. Shah R, Shah S, Sengupta S. Results al. Accuracy and precision of cap rainbow glare after laser in situ
of small incision lenticule extraction: thickness in small incision lenticule keratomileusis flap creation with a
all-in-one femtosecond laser extraction. Clin Ophthalmol 2013; 60 kHz femtosecond laser. J Cataract
refractive surgery. J Cataract Refract 7:923–26. Refract Surg. 2009; 35:1082-86.
Surg 2011;37:127–37. 17. Sachdev MS, Gupta D, Sachdev
10. Anders Ivarsen, Sven Asp, Jesper G, Sachdev R. Tailored stromal
4. Blum M, Kunert K, Gille A, et al. Hjortdal. Safety and Complications expansion with a refractive lenticule
LASIK for myopia using the Zeiss of More Than 1500 Small-Incision for crosslinking the ultrathin cornea.
VisuMax femtosecond laser and Lenticule Extraction Procedures. J Cataract Refract Surg. 2015; 41:918-
MEL 80 excimer laser. J Refract Surg. Ophthalmology 2014;121:822- 28. 23.
2009;25:350-56. 18. Sriganesh , Brar S , Rao P et al .
11. Chee Wai Wong, Cordelia Chan, Cryopreservation of Extracted
5. Li M, Zhou Z, Shen Y, Knorz MC, Gong Donald Tan et al. Incidence and Corneal Lenticules after Small
L, Zhou X. Comparison of corneal management of suction loss in Incision Lenticule Extraction for
sensation between small incision refractive lenticule extraction. J Potential Use in Human Subjects.
lenticule extraction (SMILE) and Cataract Refract Surg 2014; 40:2002– Cornea. 2014 Dec; 33:1355–62.
femtosecond laser-assisted LASIK for 10.
myopia. J Refract Surg 2014;30:94–
100. 12. Carl Zeiss Meditec AG. FLEx Option.
In: Visante Operation Manual. Jena,
6. Majid Moshirfar, MD, Michael V. Germany, 2011; 24–25.
McCaughey et al. Small incision
lenticule extraction : a review. J 13. Sekundo W, Kunert K, Russmann C, et
Cataract Refract Surg 2015; 41:652– al. First efficacy and safety study of
65. femtosecond lenticule extraction for
Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
24 DOS Times - July-August 2015
Ocular Surface
Ocular Surface and Glaucoma
Manu Saini, M. Vanathi
Concurrent use of topical cyclosporine to control ocular surface disease has been
seen to be helpful in patients with chronic glaucoma who are on long-term usage of
topical ocular hypotensive medications
Ocular surface disease is a common comorbidity causing it to evaporate more rapidly, and results in increased
finding in glaucoma patients. The diagnosis ocular dryness16. The impaired protective layer, predisposes
of ocular surface disease in the glaucoma the eye to inflammation and conjunctival metaplasia. In
addition, preservatives have destructive effects on the mucous
patient is often overlooked because the focus gland, reducing the number of goblet cells and production of
the protective mucus layer17. The three mechanisms of BAC
of management is on the evaluation of IOP toxicity described include a detergent effect, causing loss of
tear film stability, direct damage to the cornea and conjunctival
and on the markers of glaucomatous disease epithelium and immunoallergic reaction15.
progression1. Simon et al noticed prevalence of OSD in 47.6%
patients on topical antiglaucoma medication2 and 60% OSD Long-term use of topical antiglaucoma therapy, particularly
observed by Leung et al3. combination treatment regimens has been associated with
failure of glaucoma filtration surgery9,18,19. It has been shown
Topical antiglaucoma medication for duration of three that subconjunctival fibrosis develops because of increased
months or more has been found to induce significant degree of fibroblast density in the subepithelial substantia propria, linked
subclinical inflammation, which has been detected as increased to an increase in inflammatory cells9,18. Immunohistochemical
expression of HLA–DR on conjunctival epithelial cells4. Pro- study of conjunctival and trabecular specimens from
inflammatory cytokine secretion by conjunctival cells occurs in surgical patients treated with antiglaucoma eye drops has
response to topical treatment for glaucoma5. revealed significantly greater expression of fibroblastic and
inflammatory markers in samples from patients who were
The major effects of topical anti-glaucoma medication receiving preserved antiglaucoma treatment compared to
those who did not receive topical treatment9.
and their preservatives on ocular surface includes local
allergic reactions, chronic conjunctival inflammation, tear film Expression of fibroblastic and inflammatory markers
abnormalities, corneal epitheliopathy, punctuate epitheliopathy, was seen to be higher in patients receiving polytherapy
compared with those who were on monotherapy9. Intensity
medically resistant herpetic keratitis, disruption of epithelial of the inflammatory reaction seems related to the number of
function, chronic inflammatory infiltration, expression of preservative-containing medications used and duration of
inflammatory markers, impaired wound healing, squamous treatment20.
metaplasia6,7. Adverse effects of antiglaucoma medication on
The innervation of the corneal epithelial cells and the
ocular surface have been widely described. Effects could be stroma has an important influence in the corneal trophism and
contributes to the maintenance of a healthy corneal surface21.
attributed to the active component as well as to the preservative The sub-basal nerve plexus along with stromal keratocytes
which further amplify toxicity8. secrete a number of neuro-peptides, which facilitate cell
mitogenesis and migration, DNA synthesis, neurite extension
Most commonly used antiglaucoma medications – timolol and survival, keratocyte proliferation and regulation of epithelial
stem cells22. Alterations in corneal innervations impairs the
and latanoprost, when on chronic treatment can cause ocular wound healing ability of the epithelium and results in dry eye.
The neuropeptides elaborated by corneal nerves influence
surface changes. Timolol reduces tear production, probably corneal epithelial cells and these diffusible factors are believed
to stimulate the epithelial growth, proliferation, differentiation
by systemic and/or local effects of beta-adrenergic receptor and the production of collagen type VII23,24. The epithelial cells,
in reciprocation, produce the soluble factors neuronal growth
blockade in the lacrimal and/or accessory palpebral glands. It is factor (NGF) and glial cell-derived neurotrophic factor (GDNF)
also known to inhibit proliferation of corneal epithelial cells6,7. with a neurotrophic effect25.
Side effects may be related to preservative concentration, An alternative preservative to BAC is Purite®, a stabilized
duration of use, and number of instillation9. However, oxychloro complex (SOC). SOC consists of an equilibrium
mixture of 99.5% chlorite, 0.5% chlorate, and trace amounts
preservatives are needed to preserve the sterility of ophthalmic of chlorine dioxide. This preservative has been shown to have
formulations after multidose bottles are opened10-12. fungicidal, viricidal, and bactericidal activity26. Although its
Benzalkonium chloride (BAC), a quaternary ammonium www. dos-times.org 25
compound, is the most commonly used preservative in topical
ophthalmic preparations. Its turnover is very slow and may
be retained in the ocular tissues for as long as 168 hours after
application13. BAC promotes the activation of lipooxygenases,
synthesis and secretion of eicosanoids, inflammatory mediators
and many cytokines such as interleukin (IL)-1a, tumor necrosis
factor and IL-8 and IL-10, resulting in irritation, delayed
hypersensibility and allergic reactions14. Delayed and prolonged
effect of BAC is because of incorporation and persistence of BAC
molecules in cell membranes15. Preservatives exert a detergent
effect on the lipid layer of the tear film. This reduces its stability,
Ocular Surface
exact mechanism of action has not been Labbe A etal compared toxicological evaluation of chronic glaucoma patients
fully elucidated, SOC oxidizes unsaturated profile of BAC and Polyquaternium in on long-term topical therapy treated
lipids and glutathione in the cell and has experimental study, found Compared to concurrently with a topical cyclosporine
proven antimicrobial efficacy. When SOC 0.05% twice daily for 6 months compared
is instilled into the eye, it is converted PQ-1, BAC consistently and dramatically to controls. The ocular surface evaluation
into natural tear components: sodium tests, ocular surface disease (OSDI) index
and chloride ions, oxygen, and water27. altered the corneoconjunctival surface as score (OSDI)), central corneal sensation
Purite, an oxidising preservative, (Cochet Bonnett aesthesiometer), and
produced significantly less corneal evaluated by slit-lamp examination, the central confocal microscopy to study the
damage and conjunctival inflammation fluorescein test, impression cytology, in SBNFL density were studied in these at
than medications preserved with BAC28. vivo confocal microscopy, and histology31. recruitment and at the 6-month follow-
up. Schirmer’s test, ocular surface staining
SofZia, the preservative used, is an Concurrent use of topical scores, OSDI, corneal sensations, and
oxidising complex containing borate, zinc corneal SBNFLD showed a statistically
and sorbitol29, has less effect on human cyclosporine to control ocular surface significant improvement following a
cells, which contain copious amounts of 6-month concurrent topical CsA therapy
oxidases allowing the cells to withstand disease has been seen to be helpful in in these patients.
more oxidative stresses30. Thus, in
general, oxidising preservatives are safe patients with chronic glaucoma who Ocular surface needs to be evaluated
and effective at low concentrations while with care in patients who are on long term
having less impact on the ocular surface are on long-term usage of topical ocular antiglaucoma therapy with consideration
of patients requiring chronic dosing of of use of concurrent topical cyclosporine
glaucoma medications28. hypotensive medications. A prospective
to control the dry eye disease.
comparative study done to evaluate
changes in ocular surface and central
corneal sub-basal nerve fiber layer
(SBNFL) after topical cyclosporine
therapy, in chronic glaucoma patients on
long-term topical antiglaucoma therapy
has shown significant beneficial effects32.
This study evaluated the ocular surface
Cornea & Ocular Surface Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences,All India Institute of Medical Sciences, New Delhi, India
Dr.Manu Saini Dr. M.Vanathi
References 13. Champeau EJ, Edelhauser HF. Effect of ophthalmic preservatives
on the ocular surface: conjunctival and corneal uptake and
1. Dhamankar Rita et al. Prevalence of Ocular Surface Disease in distribution of benzalkonium chloride and chlorhexidine
Patients on Antiglaucoma Medications. Glaucoma session-1 digluconate. In: Holly F, Lamberts D, Mac Keen D, editors. The
AIOC 2010. preocular tear film in health, disease, and contact lens wear.
Lubbock, Texas: Dry Eye Institute Inc, 1998:292–302.
2. Simon et al. ocular surface disease and quality of life in patients
with glaucoma. Am J Ophthalmol 2012;153:1-9. 14. De Saint Jean M, Debbasch F, Brignole P, et al. Toxicity of
preserved and unpreserved antiglaucoma topical drugs in an in
3. Leung etal. Prevalence of ocular surface disease in glaucoma vitro model of conjunctival cells. Curr Eye Res 2000; 20: 85-94.
patients. J Glaucoma 2008;17:350-55
15. Yee RW. The effect of drop vehicle on the efficacy and side effects
4. Arici MK, Arici DS, Topalkara A, Guler C. Adverse effects of topical glaucoma therapy: a review. Curr Opin Ophthalmol
of topical antiglaucoma drugs on the ocular surface. Clin 2007; 18: 134-139.
Experiment Ophthalmol 2000; 28:113-17
16. Detry-Morel M. Side effects of glaucoma medications. Bull Soc
5. Malvitte L,Montange T,Vejux A et al .Measurement of Belge Ophtalmol. 2006;299:27-40.
inflammatory cytokines by multicytokine assay in tears of
patients with glaucoma topically treated with chronic drugs. 17. Herreras JM, Pastor JC, Calonge M, et al. Ocular surface alteration
Br J Ophthalmol. 2007;91:29-32. after long-term treatment with an antiglaucomatous drug.
Ophthalmology. 1992;99:1082–88.
6. Kuppens EV, Stolwijk TR, de Keizer RJ, van Best JA. Basal tear
turnover and topical timolol in glaucoma patients and healthy 18. Broadway DC, Grierson I, O’Brien C, et al. Adverse effects of
controls by fluorophotometry. Invest Ophthalmol Vis Sci topical antiglaucoma medication. I. The conjunctival cell profile.
1992;33:3442–48. Arch Ophthalmol. 1994;112:1437-45.
7. Reidy JJ, Zarzour J, Thompson HW, et al. Effect of topical beta- 19. Broadway DC, Grierson I, O’Brien C, et al. Adverse effects of
blockers on corneal epithelial wound healing in the rabbit. Br J topical antiglaucoma medication. II. The outcome of filtration
Ophthalmol 1994;78:377–80. surgery. Arch Ophthalmol. 1994;112:1446-54.
8. Wilson LA. To preserve or not to preserve, is that the question? 20. Aritu¨rk N, Oge I, Baris S, et al. The effects of antiglaucomatous
Br J Ophthalmol 1996;80:583–84. agents on conjunctiva used for various durations. Int
Ophthalmol. 1996;20:57–62.
9. Baudouin C, Pisella PJ, Fillacier K, et al. Ocular surface
inflammatory changes induced by topical antiglaucoma drugs. 21. Muller LJ, Marfurt CF, Kruse F, Tervo TM. Corneal nerves:
Ophthalmology 1999; 106: 556-63 structures, contents and function. Exp Eye Res 2003; 76: 521-
42.
10 Schein OD, Hibberd PL, Starck T, et al. Microbial contamination
of in-use ocular medications. Arch Ophthalmol 1992; 110: 82- 22. Jose´ M. Benı´tez del Castillo, Mohamed A. S. Wasfy, Cristina
85. Fernandez, Julian Garcia-Sanchez. An In Vivo Confocal Masked
Study on Corneal Epithelium and Subbasal Nerves in Patients
11. Gasset AR, Ishii Y, Kaufman HE, et al. Cytotoxicity of ophthalmic with Dry Eye. Invest Ophthalmol Vis Sci. 2004;45: 3030–35.
preservatives. Am J Ophthalmol 1974;78:98-105.
23. Garcia-Hirschfeld J, Lopez-Briones L, Belmonte C. Neurotrophic
12. Mietz H, Niesen U, Kriegelstein et al. The effects of preservatives influences on corneal epithelial cells. Exp Eye Res. 1994;59:597–
and antiglaucoma medication on histopathology of the 605.
conjunctiva. Graefes Arch Clin Exp Ophthalmol 1994; 232:
561-65.
26 DOS Times - July-August 2015
Ocular Surface
24. Baker KS, Anderson SC, Romanowski EG, Thoft RA, SundarRaj 29. Whitson JT, Cavanagh HD, Lakshman N, Petroll WM. Assessment
N. Trigeminal ganglion neurons affect corneal epithelial
phenotype: influence on type VII collagen expression in vitro. of corneal epithelial integrity after acute exposure to ocular
Invest Ophthalmol Vis Sci. 1993;34:137–44.
hypotensive agents preserved with and without benzalkonium
25. Martone G, Frezzotti P, Tosi GM, Traversi C, Mittica V,
Malandrini A, Pichierri P, Balestrazzi A, Motolese PA, Motolese chloride. Adv Ther. 2006;23:663–71.
I, Motolese E. An in vivo confocal microscopy analysis of
effects of topical antiglaucoma therapy with preservative on 30. Kahook MY, Noecker RJ. Comparison of corneal and
corneal innervation and morphology. Am J Ophthalmol. 2009;
147:725-35. conjunctival changes after dosing of travoprost preserved with
26. Masschelein WJ, Rice RG. Chlorine Dioxide. Chemistry and sofZia, latanoprost with 0.02% benzalkonium chloride, and
Environmental Impact of Oxychlorine Compounds. Ann Arbor, preservative-free artificial tears. Cornea. 2008;27:339-43.
MI: Ann Arbor Science Publishers, 1979. 31. Labbé A, Pauly A, Liang H, Brignole-Baudouin F, et al.
Comparison of toxicological profiles of benzalkonium
27. Grant R. Ajello M, Vlass E. Salt water or high tech? A look chloride and polyquaternium-1: an experimental study. J Ocul
at two new rinsing solutions for contact lenses. Optician.
1996;212:38–41. Pharmacol. 2006;22:267-78.
28. Kahook & Noecker Quantitative Analysis of Conjunctival 32. Saini M, Dhiman R, Dada T, Tandon R, Vanathi M. Topical
Goblet Cells After Chronic Application of Topical Drops. Adv
Ther. 2008;25:743–51. cyclosporine to control ocular surface disease in patients
with chronic glaucoma after long-term usage of topical ocular
hypotensive medications. Eye (Lond). 2015;29:808-14.
Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
D-8, Vikas Puri, New Delhi – 110018
Phone No’s: 011-28537777, 45623722
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Ø Ophthalmologist (MD/MS/DO/DNB) (Full Time)
Specialised in Ant. Segment Diagnosis + OPD
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Oculoplasty – on Full Time/ Part Time basis.
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www. dos-times.org 27
Oculoplasty
Periorbital Necrotising Fasciitis
Maya Hada, Neelam Pushker, Milind Changole, Mandeep S Bajaj, Rachna Meel
Necrotising fasciitis is rapidly progressing necrotizing infection of the subcutaneous
tissue and superficial fascia with secondary necrosis of the overlying skin
First recognized by Hippocrates in the fifth century Figure 1(a): Left upper eyelid necrotizing fasciitis associated with 1(b):
BC, Necrotising fasciitis (NF) is also known as skin infection. 1(c): Right eye lower eyelid necrosis with underlying
hospital gangrene, suppurative fasciitis, necrotizing suppuration associated with 1(d): periauricular infection.
erysipelas and flesh eating bacterial infection.
It is defined as rapidly progressing necrotizing Table 1: Differentiating features of Necrotizing Fasciitis
infection of the subcutaneous tissue and superficial from Cellulitis²
fascia with secondary necrosis of the overlying skin. Infection
rapidly spreads through tissues; vascular thrombosis and Very rapid spread of area of cellulitis (over hours)
tissue necrosis follow. Poor response to antibiotics appropriate for cellulitis
Extreme local tenderness (or later, anesthesia, as
Etiology subcutaneous nerves infarct)
Subcutaneous emphysema: palpated clinically or seen
The disease is usually associated with systemic problems, radiographically
most commonly diabetes and alcoholism. However, patients who Disproportionately high pyrexia, leukocytosis, and
develop periorbital NF tend not to be immunocompromised, inflammatory markers (e.g., CRP)
frequently there is a history of minor skin trauma, an insect Serosanguinous bullae or necrosis of the overlying skin
bite, or surgery (such as blepharoplasty)1. Necrotising fasciitis Hypotension (septic shock)
in periorbital region is not common because of the excellent
blood supply to this area. Periorbital NF, especially in children orbital disease is a feature of mucormycosis. Orbital NF may be
may be preceded by skin infections as erysipelas or may be complicated by cavernous sinus thrombosis, may even lead to
contiguous with periauricular infections such as mastoiditis death due to septicemia and multiorgan failure.
(Figure 1).
Imaging
Types Imaging findings are characteristic and often precede
A wide spectrum of bacteria have been found to cause evident tissue necrosis. Imaging is also important in
NF, which can be broadly classified into 2 groups: Type I NF differentiating this process from cellulitis, myonecrosis, and
(Synergistic NF) is a polymicrobial infection, consisting of a
mixture of anaerobes, Gram-negative bacilli and enterococci. www. dos-times.org 29
Type II NF is usually monomicrobial and due to gram-positive
organisms. The most common causative agent is group A
β-haemolytic streptococcus, with or without associated
infection of staphlyococcus aureus.
Clinical Features
In the early stage, there is non-specific erythma and edema
of the eyelids and the clinical picture may resemble to that of
the preseptal cellulitis. Unlike in cellulitis, patient is usually
febrile with toxic symptoms in NF (Table 1). Later, necrosis
and cutaneous gangrene occurs followed by sloughing of skin
with underlying suppuration (Figure 2). In the eyelid, where
the skin is thinner and circulation is rich, necrotizing fasciitis
is noticeable early in the disease course. Occasionally, both
eyelids become involved due to the spread of infection over the
nasal bridge.
Orbital involvement of infection causes proptosis, restricted
ocular movements and threatens vision with ophthalmic artery
thrombosis. At this stage, the clinical picture is sometimes
indistinguishable from other possible soft tissue infections and
mucormycosis. However, the orbital spread as a rule, always
follow the eyelid necrosis and suppuration in NF; whereas sino-
Oculoplasty
dense polymorphonuclear cell infiltrate.
Numerous bacteria are often seen within
the areas of suppurative inflammation.
Figure 2(a): 2 year old child presented with right upper eyelid erythma and edema rapidly Management
progressed to necrotising fasciitis. 2(b): Post debridement of the devitalized tissue, underlying
healthy orbicularis muscle is visible. The skin defect was covered with full-thickness skin graft Treatment consists of parenteral
later. antibiotics and surgical debridement.
Early surgical debridement, with removal
mucormycosis. from other types of soft tissue infections of all devitalized tissue is the mainstay
CT scan in NF shows gas within the based on laboratory investigations. The of management. Debridement lowers
indicators for NF infection are white mortality by directly reducing bacterial
fascia distributed in a linear plane, with cell count, CRP, haemoglobin, sodium, load and, consequently, production of
predominance of fascial (rather than creatinine and glucose. A score of six or collagenase and hyaluronidase (which
muscular) involvement, and associated more should raise the suspicion of NF facilitate spread of infection), M proteins,
inflammation of subcutaneous fat and and a score of eight or more is strongly and SPEs (Streptococcal Pyogenes
skin. Whereas, the CT appearance predictive of the disease. Exotoxins). Infected, devitalized and
of cellulitis shows swelling of the anaesthetized subcutaneous tissue
affected area, increased attenuation of Pathology should be debrided until viable
subcutaneous tissue and disappearance vascularized tissue is identified, while
of the sharp distinction between the Tissue biopsies taken for preserving as much skin as possible to
subcutaneous muscle and fat. MRI is more histopathological assessment must optimize cosmesis. Exenteration (Figure
helpful in distinguishing necrotizing include the advancing edge and central 4) is often required in orbital NF poorly
fasciitis and cellulitis, as it shows the necrotic areas.. It shows intense responding to surgical debridement, as
areas of necrosis evidenced by low signal suppurative inflammation in the the progression may lead to cavernous
intensity on T1 weighted images and fibrofatty tissue planes of the eye lids and sinus thrombosis.
failure to enhance with IV gadolinium orbit, with areas of cutaneous ulceration.
(Figure 3). Vascular thrombosis is seen in the Antimicrobial therapy is of
subcutaneous and subepidermal tissues, secondary benefit, since drug
The LRINEC (Laboratory Risk with necrosis of deep fascia, micro penetration into ischemic tissue is poor.
Indicator for Necrotising Fasciitis), is a abscesses, fibrosis, hemorrhages, and a However, there are reports that suggest
tool developed to help distinguish NF that surgical debridement was not
necessary in some of the patients with
Figure 3a&b: Axial (a) and coronal (b) MRI showing marked periorbital edema in acute stage of periorbital necrotizing fasciitis limited
necrotising fasciitis. to eyelids without severe morbidity, in
presentations like preseptal cellulitis
and in patients at time of presentation3.
They have showed improvement with
early antibiotic therapy and recovered
completely without the need for
debridement. If streptococci are the
identified major pathogens, parenteral
Penicillin-G is given with clindamycin as
an alternative. The anaerobic coverage
is provided by Metronidazole. A high
index of suspicion is therefore required
with prompt institution of antibiotics.
Hyperbaric oxygen therapy is occasionally
used adjunctively.
The major morbidity is loss of
skin and soft-tissue leading to cosmetic
disfigurement and functional problems
that need to be addressed subsequently.
Scarring in the periorbital region and
eyelids lead to cicatricial ectropion and
Oculoplasty, Dr. Rajendra Prasad Centre for Ophthalmic Sciences,All India Institute of Medical Sciences, New Delhi, India
Dr. Maya Hada MD Dr. Neelam Pushker MD Dr. Milind Changole MD Dr. Mandeep S. Bajaj MS Dr. Rachna Meel MS
30 DOS Times - July-August 2015
Oculoplasty
Mortality from periorbital NF has been
reported to be approximately 10–15%
and is associated with toxic shock
syndrome and multiorgan failure. Early
diagnosis and prompt treatment can
avert morbidity such as visual loss and
mortality.
Figure 4(a): Orbital spread of the extensive periorbital necrotising fasciitis post electrocution References
injury. 4(b): Exenterated socket with healthy granulation tissue.
1. Marshall DH et al. Periocular
Figure 5 a & b: Left upper eyelid cicatricial ectropion (a) and lagophthalmos (b) following scarring necrotizing fasciitis: a review
after debridement of necrotising fasciitis of five cases. Ophthalmology.
1997;104:1857-62.
significant lagophthalmos (Figure 5), stage. Another reason for morbidity is
which can be complicated by exposure loss of vision because of either central 2. Anish N. Shah et al. Eyelid Necrotising
keratopathy. Early skin grafting to correct retinal artery occlusion or orbital spread Fascitis : What were the early signs?
lagophthalmos is required in cicatricial necessitating removal of orbital contents. The Journal of Emergency Medicine,
2013;44.:349–51.
3. Mehta R et al. Medical management
of periorbital necrotising fasciitis.
Orbit. 2013;32:253-5.
4. Shayegani A et al. Streptococcal
gangrene of the eyelids and orbit. Am
J Ophthalmol. 1995;120:784-92.
5. Amrith S et al. Periorbital necrotizing
fasciitis - a review. Acta Ophthalmol.
2013;91:596-603.
6. Lazzeri D et al. Periorbital
necrotising fasciitis. Br J Ophthalmol.
2010;94:1577-85.
7. Puri P et al. Necrotising fasciitis
of the orbit: early recognition and
treatment a key to success. Eur J
Ophthalmol. 2001;11:180-2.
8. Kronish JW et al. Eyelid necrosis
and periorbital necrotizing fasciitis.
Report of a case and review of
the literature. Ophthalmology.
1991;98:92-8.
9. Khurana S, Pushker N et al. Periorbital
necrotising fasciitis in infants:
Presentation and management of six
cases. Trop Doct. 2015 Mar 17.
Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
www. dos-times.org 31
RETINA
Vitreomacular Traction Syndrome – Pathogenesis,
Clinical Features,Classification
Anand Rajendran, Bhanu Pangtey
The vitreous is a gel like structure that occupies During anomalous PVD formation, vitreoretinal
about 4 ml of intraocular space. It is composed adhesions develops in areas in which the
mostly (98%) of water, and two major posterior hyaloid is firmly attached to the retina
due to the extracellular matrix and where ILM is
macromolecules-collagen (type II, hybrid of
thinnest
types V/XI and type IX collagen in a molar ratio
of 75:10:15) and hyaluronan1. Collagen fibers partial posterior vitreous detachment (PVD)9. In 1970, Resse
stream in an anteroposterior direction from the vitreous base et al described both clinically and histologically, a variant of
VMT associated with partial vitreous detachment with focal
to the posterior cortex. The posterior vitreous cortex consists of vitreous adherence to the macula causing foveal thickening
densely packed collagen fibrils (100–300 mm in thickness) that and decease in visual acuity10. In a review by William Smiddy
lie over the macula and these are superficially inserted into the et al11, the authors put forward the series of events that may
internal limiting membrane (ILM) of the retina2. Not only does lead to VMT formation. They postulated that either incomplete
vitreous detachment may induce cell migration from the retina
it provide support to the retina, but it also consumes oxygen on the vitreoretinal interface or the preexisting cell membranes
on the retinal surface may cause an area of firm vitreoretinal
and reduces the oxidative stress to the lens. It has been shown adhesion which prevents the separation of posterior vitreous
cortex. Fibrous astrocytes were the predominant cells on the
that the loss of the crystalline lens and vitreous surgically, retinal surface. Notably there was an absence of RPE cells
which are predominantly seen in epiretinal membranes (ERM).
increases the risk of developing some form of primary open Various postulations were given for the source of these cells.
glaucoma by 15%3. Metaplasia of cells may be responsible for the presence of RPE
in superficial retina as Vinores and associates found out that
Posterior vitreous detachment or PVD is defined as a though these cells had typical morphological features of RPE
separation between the posterior vitreous cortex and the ILM but they did not express expected antigenic profile12.
of the retina4. It is considered an acute event precipitated by
In study conducted by Chang et al13, they used Spectral
the abrupt development of a break in the thin posterior cortical Domain Optical coherence tomography (SD-OCT) to map the
vitreous layer overlying the macular region5. posterior hyaloid surface along with retinal scans and they also
took histological samples of the posterior hyaloid phase during
During anomalous PVD formation, vitreoretinal adhesions surgical intervention. They found ERMs in areas with PVD and
develops in areas in which the posterior hyaloid is firmly
attached to the retina due to the extracellular matrix and where
ILM is thinnest, mainly, at the 500 µm diameter foveolar area
and the margin of the 1,500 µm fovea (Figures 1,2)6,7. These
adherences may exert traction forces on the macula, and ocular
saccades increases the effect of traction leading to retinal
distortion and foveal detachment8.
VITREOMACULAR TRACTION SYNDROME (VMT), as
described by Jaffe in 1967, is a well-recognized complication of
Figure 1: Anomalous PVD and related complications
www. dos-times.org 33
RETINA
a membrane which coursed up type. In the V type, there is a
on the hyaloid surface using perifoveal vitreous detachment
SD-OCT. Histologically, they with persistent vitreomacular
determined that cells on the adhesion (Figure 6). In the J
hyaloid phase were similar type, there is an incomplete
to that of ERMs. Strikingly posterior vitreous detachment
RPE cells were present on with persistent nasal attachment
the hyaloid phase which had but detachment temporal to the
not been reported till then. fovea (Figure 7). It is observed
They proposed a role for that the diameter of area involved
ERMs in VMT pathogenesis (focal or broad) leads to specific
and postulated that PVD may macular changes in the V and
lead to micro perforation J type VMTs15. V-shaped and
at the level of ILM allowing Figure 2: OCT image depicting Anomalous PVD and the posterior focal VMT were found to lead to
access of glial cells to the vitreous cortex tractional CME and macular hole
superficial retinal layers, while J-shaped and broad VMT
which acts as scaffolding for were related to ERM and diffuse
(ERM) proliferation. ERMs also retinal thickening.
proliferates on the detached Spaide et al16 popularised
hyaloid, anchoring vitreous on the concept of the area of
to the macula (Figures 3). attachment and its relation
In VMT, the vitreous with ocular morbidity. He
separates from the retina proposes that the diameter of
throughout the peripheral the vitreomacular attachment
fundus but remains adherent is inversely related to macular
posteriorly, resulting in morbidity and foveal deformation.
anteroposterior traction on a The narrower the vitreomacular
broad, often dumb-bell shaped attachment, the greater the force
region encompassing the exerted on the macula, whereas
macular area and optic nerve, Figure 3: OCT image depicting VMT with ERM diffuse vitreomacular adhesion
usually several disc areas in might distribute the tractional
size. Johnson et al described force beyond the foveal border.
the early complications of Tractional CME is a variant
PVD with respect to the area of the VMT syndrome associated
of adhesion. He reported with unifocal vitreofoveal
that VMT is characterized traction arising from partial
by macular adhesions of the PVD. Clinically, tractional CME
hyaloid of about 1,500 µm can be confused easily with
while vitreofoveolar traction pseudophakic or uveitic CME but
is the term employed when Figure 4: OCT image depicting Focal VMT
absence or minimal leakage on
the macular adhesion is below fluorescein angiography may help
500 µm7. Vitreomacular Adhesion or VMT has been classified into the in differentiating one from the other. OCT
VMA has been defined as the attachment broad or focal types. The maximal also helps in highlighting the tractional
of the vitreous cortex in a 3mm radius diameter of focal variant is less than component, thereby, making the diagnosis
around the fovea with detachment of the 1500 µm (Figures 4); if the area under easier17. Tractional detachments may
perifoveolar cortex with, critically, no traction extends beyond 1500 µm, it is occur in severe cases of VMT which could
distortion of the foveal morphology. The considered to be a broad variant (Figures be broad (Figure 8) or foveal TRDs in cases
5). VMT has also been classified on the of isolated vitreofoveal traction (Figure
classic definitions of VMA and VMT with 9). Macular holes may also develop in the
their classifications14 are elucidated in basis of the morphology of the traction
Appendix 1. and it divides VMT into V type and J VMT syndrome (Figures 10,11). This is
1. Senior Consultant & Professor,Vitreo-Retinal Service,Aravind Eye Hospital, Madurai.
2. Retina Fellow,Vitreo-Retinal Service,Aravind Eye Hospital , Madurai
Dr.Anand Rajendran1 FRCS,DNB Dr. Bhanu Pangtey2
34 DOS Times - July-August 2015
RETINA
Appendix 1 - Definitions & Classifications References
Vitreo Macular Adhesion – (VMA) Definition 1. Balazs EA (1961) Molecular morphology
• Evidence of perifoveal vitreous cortex detachment from the retinal surface.
• Macular attachment of the vitreous cortex within a 3-mm radius of the fovea. of the vitreous body. In: Smelser GK (ed)
• No detectable change in foveal contour or underlying retinal tissues.
The structure of the eye. Academic, New
VMA Classification
York, pp 293–310
By size of attachment area
• Focal (≤1500 µm) 2. D. H. W. Steel and A. J. Lotery, “Idiopathic
• Broad (>1500 µm, parallel to RPE and may include areas of dehiscence)
vitreomacular traction and macular
By presence of concurrent retinal conditions
• Isolated hole: a comprehensive review of
• Concurrent
pathophysiology, diagnosis, and
Vitreo Macular Traction – (VMT) Definition
• Evidence of perifoveal vitreous cortex detachment from the retinal surface. treatment,” Eye, vol. 27, pp. S1–S21,
• Macular attachment of the vitreous cortex within a 3-mm radius of the fovea.
• Association of attachment with distortion of the foveal surface, intraretinal 2013
structural changes, and/or elevation of the fovea above the RPE, but no full- 3. Chang S. LXII Edward Jackson lecture:
thickness interruption of all retinal layers. open angle glaucoma after vitrectomy.
Am J Ophthalmol. 2006; 141:1033-43
4. Foos RY, Wheeler NC. Vitreoretinal
juncture: synchysis senilis and posterior
vitreous detachment. Ophthalmology
1982;89:1502–12.
5. Eisner G. Posterior vitreous detachment.
Klin Mbl Augenheilk 1989;194:389 –92.
6. Sebag J. Anatomy and pathology of the
vitreo-retinal interface. Eye (Lond)
1992; 6 (Pt 6):541–52.
7. Johnson MW. Posterior vitreous
detachment: evolution and
complications of its early stages. Am J
Ophthalmol 2010;149:371–82.
8. B. Coscostegui, J. G. Arum´ ´ı, and M.
G. Resa, “Adhesion vitreomacular y
desprendimiento posterior del vıtreo,”
in Diagnostico y Clasificacion de la
Figure 8: OCT image depicting Broad VMT Traccion Vitreomacular y El Agujero
with TRD Macular, J. G. Arum´ı, Ed., pp. 3–17,
Figure 5: OCT image depicting Broad VMT
with Tractional Schisis Euromedicine, Badalona, Spain, 2014.
Figure 9: OCT image depicting VFT with 9. Jaffe NS. Vitreous traction at the
Foveal TRD
posterior pole of the fundus due to
alterations in the vitreous posterior.
Trans Am Acad Ophthalmol Otolaryngol
1967;71:642– 52.
10. Reese AB, Jones IS, Cooper WC.
Vitreomacular traction syndrome
confirmed histologically. Am J
Ophthalmol 1970;69:975–77.
11. Smiddy WE, Michels RG, Green WR.
Morphology, pathology, and surgery
of idiopathic vitreoretinal macular
disorders. A review. Retina 1990;
10:288–96.
12. Vinores SA, Campochiaro PA, Conway
BP. Ultrastructural and electron-
immunocytochemical characterization
of cells in epiretinal membranes. Invest
Figure 6: OCT image depicting V type VMT Ophthalmol Vis Sci 1990;31:14–28.
Figure 10: OCT image depicting VMT and Full
thickness Macular Hole Stage 3 13. Chang LK, Fine HF, Spaide RF, et al.
Ultrastructural correlation of spectral
domain optical coherence tomographic
findings in vitreomacular traction
syndrome. Am J Ophthalmol 2008;
146:121–27.
14. DeCroos FC, Toth CA, Folgar FA, et
al. Characterization of vitreoretinal
interface disorders using OCT in
the interventional phase 3 trials of
ocriplasmin. Invest Ophthalmol Vis Sci
2012;53: 6504–11.
Figure 7: OCT image depicting J type VMT 15. J Botto´ s, J Elizalde, EB Rodrigues,
M Farah et al. Classifications of
due to the tractional schisis phenomenon
leading onto focal CME, foveal tissue Figure 11: OCT image depicting VMT and vitreomacular traction syndrome:
distortion, and subretinal detachment. Outer Lamellar Hole
These cases can be considered a variant diameter vs morphology. Eye (2014) 28,
of the VMT syndrome, linking it to macular holes. The advent and advances
progression of MH formation. in Optical Coherence Tomography 1107–12
have vastly helped us understand the
VMT is associated with a spectrum of intricacies in the aetiopathogenesis of 16. Spaide RF, Wong D, Fisher Y, et al.
disorders ranging from cystoid macular the Vitreomacular traction syndrome as
edema, epiretinal membrane and well as many other vitreoretinal interface Correlation of vitreous attachment and
disorders.
foveal deformation in early macular hole
states. Am J Ophthalmol 2002; 133:226–
29.
17 Johnson MW. Tractional cystoid
macular edema: a subtle variant of the
vitreomacular traction syndrome. Am J
Ophthalmol 2005; 140:184–92.
Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
www. dos-times.org 35
RETINA
Vitreo Macular Traction - Management
Cyrus M. Shroff, Charu Gupta
Vitreo macular adhesion (VMA) can be considered a normal stage in the natural
history of PVD associated with vitreous aging. Only when symptoms are present
or when foveal anatomic changes are observed, VMA becomes pathological and is
referred to as vitreo macular traction (VMT)
Treatment of vitreo macular traction (VMT) Therefore, in patients of VMT with good visual acuity
without Macular Hole is often a quandary. VMT and mild to moderate symptoms the first approach is to
may progress to macular hole formation, it may observe for 3 months and re-examine the patients using OCT
resolve with spontaneous posterior vitreous (Figure 1). Patient should be advised to perform periodic self-
detachment and improved visual acuity (VA), examinations with the Amsler grid or monocular reading tests.
or it may remain dormant. There are no reliable In case intensity of symptoms or disability increases they can
predictors of its course; hence, severity and progressive be reassessed earlier (Figure 2).
traction are important factors in prompting intervention. A
detailed discussion with the patient vis a vis his symptoms, how Progression of Vmt Over 6 Mths
it affects his daily activities, his expectations after intervention Vision Declined from 6/5, N5 To 6/18, N8 –
and time period of recovery is important and influences the Taken up for Surgery
decision making process.
Figure 1: Case 1- OCT of Left eye 62 year old man showing progression
Observation, pharmacologic vitreolysis with ocriplasmin, of VMT over 6 months.
and surgical treatment are the treatment options that will be
discussed with guidelines on the path to be followed according Stable Vmt on Observation – Vision Remained
to the initial presenting manifestations and the patient’s clinical Stable at 6/5, N5 at 6 months follow up
course. Figure 2: Case 1- OCT of Right eye 62 year old man showing VMT on
observation.
OBSERVATION
Vitreo macular adhesion (VMA) can be considered a
normal stage in the natural history of PVD associated with
vitreous aging. Only when symptoms are present or when foveal
anatomic changes are observed, VMA becomes pathological
and is referred to as VMT. Sequential SD-OCT enables accurate
assessment of this physiological process that may evolve into
VMT, remain stable, or resolve spontaneously. Initial observation
is indicated in most cases of VMT without macular hole1. An
exception would be patients with documented VMT on SDOCT
who have decreased visual acuity with metamorphopsia.
In a recent OCT based study John et al.2 studied the
spontaneous clinical course of VMA in 106 eyes of 81 patients
(mean follow-up of 18 months). VMA was diagnosed and
classified based on SD-OCT into three grades: Grade 1 (41%)
was incomplete cortical vitreous separation with attachment
at the fovea, Grade 2 (52%) was the Grade 1 findings and any
intraretinal cysts, and Grade 3 (7%) was the Grade 2 findings
and the presence of subretinal fluid. By the last follow-up,
spontaneous release of VMA occurred in 32% of cases. No
change was observed in 52% of the cases and progression
occurred in 16% of the cases. Mean best corrected logMAR
visual acuity was 0.269 at baseline and 0.251 at last observation.
Stability of visual acuity, high rate of sponataneous traction
release (32%) and a low rate of progression to a more severe
anatomical configuration (16%) led the authors to conclude
that the clinical course of patients with VMT managed by initial
observation was favourable2.
www. dos-times.org 37
RETINA
INTRAVITREAL OCRIPLASMIN group versus 14.3% in the placebo group use of the drug began, there have been
(P<0.001). some unfavourable reports of visual
Pharmacologic vitreolysis with disturbances after ocriplasmin injection,
ocriplasmin is a new nonsurgical With regard to secondary variables including transient but profound visual
treatment modality to induce PVD (day 28), 13.4% of patients treated decline, raising concerns regarding
thereby relieving vitreomacular traction with ocriplasmin showed total PVD as its safety. Reversible disruption in the
and avoiding the potential complications compared to 3.7% of those treated with ellipsoid zone on SD-OCT, persistence of
of vitrectomy. Ocriplasmin (Jetrea; placebo (P<0.001). Also, nonsurgical subretinal fluid and ERG abnormalities
ThromboGenics, Inc, Iselin, New Jersey, closure of full-thickness MH was achieved have been documented in patients with
USA) is a recombinant truncated protease in 40.6% of ocriplasmin-treated patients loss of vision.
subunit of human plasmin that can and in 10.6% of placebo-treated patients
induce vitreous liquefaction and has (P<0.001). An ongoing phase 3b, 24-month
proteolytic activity at the vitreoretinal randomized clinical trial is evaluating
interface. More specifically, it hydrolyzes According to the investigator’s ERG and microperimetry in ocriplasmin-
the peptide bonds of laminin, fibronectin, criteria, all patients could be treated treated eyes compared to sham.
and collagen-molecules that maintain the with vitrectomy in the framework of the
extracellular matrix adhesion between study if macular disease did not resolve. Pharmacologic vitreolysis though
the posterior hyaloid and the internal At 6 months, vitrectomy was performed carrying a lower success rate than
limiting membrane (ILM)1,3,4. in 17.7% of patients in the ocriplasmin vitrectomy, provides an alternative
group and in 26.6% of those in the placebo for patients who have overriding
The efficacy and safety of group (P<0.001). At 6 months, there were travel needs that preclude a gas
ocriplasmin has been evaluated in two statistically significant differences in injection; difficulties with surgery and
pivotal, phase 3 clinical trials (TG-MV-006 favour of ocriplasmin in the gain of two postoperative management, such as
y TG-MV-007) carried out in the United or more lines (23.7% versus 11.2%) or positioning; or would have a significant
States and Europe. Overall, 652 patients three or more lines (12.3% versus 6.4%). benefit from avoiding cataract surgery. Its
were randomized, 464 were assigned relatively lower invasiveness (compared
to treatment with a single intravitreal After approval of the use of with PPV) might prompt expanded
injection of ocriplasmin (125μg) and 188 intravitreal injection of ocriplasmin for treatment indications for patients with
to a placebo intravitreal injection. The the treatment of symptomatic VMT and lesser degrees of symptoms or VMA once
primary endpoint was the pharmacologic MH by the Food and Drug Administration doubts about its safety have been cleared.
resolution of VMA at day 28, as (FDA) in the United States, in November At present its high cost per dose and low
determined by OCT. Secondary endpoints 2012, and by the European Medicines success rate are also limiting factors for
included the percentage of patients with Agency (EMA) in May 2013 there have its worldwide acceptance as a treatment
complete PVD and nonsurgical closure been many reports providing data of modality for VMT5.
of full-thickness MH at day 28. Eligible the use of ocriplasmin in daily practice.
patients had symptomatic focal VMA as Most studies have shown resolution of SURGERY
seen on OCT and a best-corrected visual vitreomacular traction in approx 40% of
acuity of 20/25 or less. Exclusion criteria eyes, with better success rate in patients Patients of VMT with decreased
were high myopia (more than−8 diopters meeting the four positive predictor visual acuity, good visual acuity with
or axial length > 26 mm), prior vitrectomy criteria (younger than 65 years, no ERM severe metamorphopsia and moderately
or prior laser photocoagulation of the at baseline, traction <1500 μm, and symptomatic VMT that fail to improve
macula, and other eye diseases that may phakic lens status). with observation, or demonstrate
affect visual acuity. Patients with a MH > progression of the traction effects are
400μm in diameter were also excluded. The most common complications indications for PPV. There is no consensus
in the trials included vitreous floaters on level of visual acuity that should be
At day 28, VMA resolved in 26.5% of (ocriplasmin 16.8% versus placebo 7.5%), considered significant but usually a visual
ocriplasmin-injected eyes and in 10.1% photopsia (11.8% versus 2.7%), blurred acuity of 6/12 or worse is taken as an
of placebo-injected eyes (P <0.001). vision (8.6% versus 3.2%), and visual indication for PPV.
The between-group differences did not impairment (5.4% versus 1.6%). Most
change substantially at 6 months (26.9% of these adverse events were transient If the option of Ocriplasmin is
ocriplasmin versus 13.3% placebo and mild in severity. There were no available and traction is ≤1500μm,
(P<0.001). Also, 72% of patients with differences between the groups in terms enzymatic vitreolysis with ocriplasmin is
resolution of VMA showed the release of severe ocular adverse events, including the treatment of choice. However, in the
during the first seven days. Results of development of MH (5.2% versus 8.6%), presence of >1500μm traction or ERM,
adhesion release were better in patients retinal detachment (0% versus 1.6%), surgical treatment with vitrectomy is
without ERM (37.4% in the ocriplasmin and reduced visual acuity (0.6% versus associated with better outcomes. In cases
0.5%). However, since the real-world
Vitreo-retina Services, Shroff Eye Centre A-9, Kailash Colony, New Delhi, India
Dr. Cyrus M. Shroff MD Dr. Charu Gupta MS
38 DOS Times - July-August 2015
RETINA
VITREOMACULAR TREATMENT ALGORITHM MACULAR HOLE (MH)
ADHESION (VMA)
VITREOMACULAR
ASYMPTOMATIC TRACTION (VMT)
OBSERVATION SYMPTOMATIC SYMPTOMATIC
(FOLLOWUP AND OCT VA BETTER THAN 6/12 VA WORSE THAN 6/12
EVERY 3 MONTHS)
OBSERVATION
STABLE VA WORSENS
CONTINUE OBSERVATION CLINICALLY SIGNIFICANT
METAMORPHOPSIA
WITH ERM, WITHOUT ERM, WITH ERM,
TRACTION>1500u TRACTION>1500u TRACTION>1500u
INTRAVITREAL
OCRIPLASMIN
EXAMINATION AT 1 MONTH
NO VMT RESOLUTION VMT RESOLUTION
OBSERVATION SURGERY (PPV)
Figure 3: Vitreo Macular Traction
treated with Ocriplasmin if resolution detachment (4.6%). Study concluded that CONCLUSION
of VMT and/or hole closure had not vitrectomy for VMT was safe and though Vitreo-macular traction is
characterized by anomalous PVD
occurred after a month of treatment, the visual acuity improvement was modest accompanied by anatomic distortion of the
fovea which may include macular schisis,
likelihood of success is highly improbable the visual acuity change may not fully cystoid macular edema, pseudocysts
and subretinal fluid. VMT is FOCAL
and vitrectomy is indicated. reflect symptomatic relief6. when diameter of vitreous attachment
A metaanalysis of Pars Plana A treatment algorithm (Figure 3) to the macular surface is 1500µ
outlines guidelines for management. or less, BROAD when greater
Vitrectomy for vitreomacular traction by than 1500 µ and CONCURRENT
Jackson et al studied the safety and efficacy when associated with other
macular disease like Macular
of the procedure. 21 of the 460 articles Hole or ERM. Asymptomatic &
minimally symptomatic VMT can
reporting visual acuity change Preoperative BCVA 6/18, N10 be safely observed. Intervention
before and after pars plana Preoperative OCT is indicated when the patient is
vitrectomy were selected using definitely symptomatic or when
the visual acuity is documented
a systematic literature review to be deteriorating. Given the
with predefined eligibility success rates and high safety
profile of MIVS, vitrectomy is the
criteria. Mean logMAR visual
acuity improved from 0.67
+/- 0.55 to 0.42 +/- 0.45
(n=259 eyes) after pars plana
vitrectomy. One third of eyes
gained 2 Snellen lines after
surgery. Studies of patients Post Operative BCVA 6/9, N6
undergoing ILM peeling were Postoperative OCT
compared with those in which
no ILM peeling was done. No intervention of choice for these
difference in visual gain was cases (Figure 4). Pharmacological
seen between the two groups. vitreolysis with Ocriplasmin may
Cataract was the most common have a role in selected cases of
postoperative complication focal VMT & very small macular
seen (63.2% of phakic holes upto 250µ in diameter.
eyes) followed by epiretinal Figure 4: Pre and Posoperative Oct of a patient who underwent
membrane (5.7%) and retinal surgery for Vmt
References outcomes and Spectral-Domain E. Smiddy, MD. Cost evaluation of
Optical Coherence Tomography surgical and pharmaceutical options
1. Alfredo García-Layana et al., A findings of eyes with symptomatic in treatment of vitreomacular
Review of Current Management of vitreomacular adhesion treated adhesions and macular hole.
Vitreomacular Traction and Macular with intravitreal ocriplasmin. Am J Ophthalmology 2014;121:1720-26.
Hole, Journal of Ophthalmology. Ophthalmol 2015;159:20–30. 6. Jackson et al. Pars plana vitrectomy
March, 2015. 4. Stalmans et al., OCT based for vitreomacular traction
interpretation of the vitreomacular syndrome - A systemstic review and
2. V. J. John, H. W. Flynn, W. E. Smiddy et interface and indications for metaanalysis of safety and efficacy.
al., Clinical course of vitreomacular pharmacologic vitreolysis. Retina Retina 2013;33: 2012-17.
adhesion managed by initial 2013; 33: 2003-11.
observation, Retina 2014; 34: 442–46. 5. Jonathan S. Chang, MD, William
3. Warrow et al., Treatment
Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
www. dos-times.org 39
SQUINT & NEURO-OPHTHALMOLOGY
Novel Device for Quantification of Relative
Afferent Pupillary Defect: RAPDX
Pooja Mehta, Pooja Bandivadekar, Amrita Ajani, Rohit Shetty
RAPD is a tool for functional assessment having diagnostic and
prognostic value in various diseases.
Ophthalmic assessment is incomplete without Table 1: Clinical grading of RAPD
a thorough pupillary examination. Pupillary
reactions are a window to a plethora of ocular Grade of RAPD Clinical assessment
as well as systemic diseases. Relative afferent
pupillary defect is one of the most common Grade I a weak initial constriction and greater re-
pupillary reaction abnormality in clinical dilatation
practice. An abnormal simple swinging flash light test can
open a Pandora’s Box of possibilities; asymmetric glaucoma, Grade II initial stall and greater re-dilatation
retinal diseases, optic nerve pathology, retro-orbital tumors,
pituitary tumors, multiple sclerosis and rarely cerebrovascular Grade III immediate pupillary dilatation
anomalies1-4.
Grade IV immediate pupillary dilatation following
Clinical assessment of Relative Afferent prolonged illumination of the good eye
Pupillary Defect (RAPD) for 6 seconds
A light source is alternately shone into the left and right Grade V immediate pupillary dilatation with no
eyes. A normal response would be equal constriction of both secondary constriction
pupils, indicating an intact direct and consensual pupillary
light reflex. When the test is performed in an eye with an RAPD - relative afferent pupillary defect
afferent pupillary defect, light directed in the affected eye will
cause mild constriction of both pupils followed by dilatation using NDF. The neutralization in this test is also subjective and
in mild disease or direct dilation in severe disease. The test is
performed. inter-observer variation may continue.
Ø In dimly lit room
Ø With a steady, bright light source RAPDx (Konan Medical INC, Irvine CA, USA) is a novel tool
Ø With the patient fixing at infinity (gazing at distance to
based on infrared pupillometry. Using the RAPDx, the light
avoid near reflex) stimulus to the retina can be controlled and quantified. Also,
Ø After ascertaining the pupil’s ability to react to light a specific quadrant of retina can be stimulated at a given time.
(Table 2) briefly describes the difference between NDF and
There are multiple variables in accurately performing RAPDx.
the test in a repeatable manner including the background
luminosity and the illumination of torch light. This is a highly RAPDx: Quantifying pupillometry
subjective test and inter-examiner variation definitely exists.
Bell et al5 had clinically classified RAPD into 5 grades (Table 1). Principle: Binocular infrared computerized pupillometry
However, RAPD assessment continued to be a subjective test. Device: RAPDx is a compact table mounted machine
(Figure 1). The patient faces a small LCD screen which displays
Why do we need automated quantification of a green cross as a target for fixation and also generates the
RAPD? stimulus. The screen has a central barrier which creates two
optical channels, one for each eye. During testing, each portion
RAPD is a tool for functional assessment having diagnostic of the screen can be enabled selectively to achieve separate
and prognostic value in various diseases. Subtle changes
in magnitude of RAPD are difficult to detect by naked eye Figure 1: The RAPDx machine being used on a patient
examination. Worsening of disease or improvement with www. dosonline.org 41
therapy may not be assessed on clinical examination. Non-
automated semi-quantitative tests using neutral density filters
(NDF) have also been tested. Neutral density filter allows
assessment in 0.3 Logarithm unit steps6. However, evaluating
changes of lesser magnitude than 0.3 Log Units is not possible
SQUINT & NEURO-OPHTHALMOLOGY
Figure 2: Stimulus Patterns and Colours. Note the partial field macula sparing and quadrantic definition biometric waveform, the
stimuli that can be used. RAPDx Signature™, which characterizes
key features of pupil defect responses
Table 2 beyond those seen by human observers.
The analysis software converts the
RAPDx Neutral density filter generated pupil diameter waveforms into
specific metrics. The repetitions from
Intensity of light Uniform intensity of light Dependent on flashlight each eye are averaged (median) before
analysis to minimize noise inherent in the
used battery pupil responses.
Examiner bias/ Totally objective test Largely examiner Procedure: Testing is conducted
dependant/subjective under dark room conditions. After a short
Neutralization of end point period to allow subjects to adjust to the
dark, they were asked to look at a fixation
Defect that can be 0.1 log units 0.3 – 3.6 log units target. Eyes are illuminated by a pair of
measured infrared emitting diodes (peak 880 nm)
mounted at a 35° angle. Under infrared
Progression of disease Can be picked in milder Difficult to pick up conditions information regarding the
cases ‘‘dark’’ pupil diameter is captured as
camera pixels and this measurement
stimulation of each eye. Objective lenses RAPD Score converted to millimeters using a scaling
factor. The stimulus is then presented as
(50 mm focal length) are arranged such Healthy subject Zero a series of trials, either to the full field
that the screen is viewed at infinity of each eye or limited to predetermined
providing an approximate 25° field of Relative abnormality of Positive regions. The full field stimulus extends
view in each eye. RAPDx is enabled with the Left afferent system value to approximately 18° from fixation. Each
trial consists of a period of stimulation
eye tracking, automated blink detection Relative abnormality Negative followed by a period of darkness during
of the Right afferent value which the cameras record continuously.
and rescheduling i.e if a blink obscures system The total time of each trial is 2.0 seconds
plus a 100-ms post trial rest period
the pupil during recording, the test is Ø Multi-intensity during which no images are acquired.
Ø Full-field, macular and macula
repeated automatically. Parameters measured
sparing
Stimuli: RAPDx presents patented Ø Quadrantic Ø Pre-stimulus pupil diameter (in
monocular stimuli while the patient is millimeters).
Software: RAPDx records a high-
viewing binocularly. The stimuli can be of Ø Minimum pupil diameter following
the stimulus (in millimeters).
following types (Figure 2).
Ø White light and multi-chromic Ø The amplitude (defined as the ratio
of the maximum change in pupil size
divided by the resting pupil size).
Ø Response latency (time in
milliseconds between stimulus onset
and time when pupil velocity has
reached 50% of the peak velocity of
constriction).
Ø Time to peak constriction (in
milliseconds) and response
amplitude which is the maximal
contraction of the pupil as a
percentage of the pre-stimulation
size, that is, the pre-stimulus pupil
Narayana Nethralaya Rajaji Nagar, Bengaluru, Karnataka, India
Dr. Pooja Mehta Dr. Pooja Bandivadekar Dr.Amrita Ajani Dr. Rohit Shetty
42 DOS Times - July-August 2015
SQUINT & NEURO-OPHTHALMOLOGY
diameter minus the minimum RAPD. However, to investigate the effect correlation between the magnitude of
pupil diameter, divided by the pre- of potential confounders, such as average RAPD and intereye differences in mean
stimulus pupil diameter. disease severity, the absolute RAPD score deviation and estimated Retinal Ganglion
also was calculated as an overall measure Cell counts suggesting that pupillometry
RAPD Score of asymmetry of the afferent visual may be useful for quantifying asymmetric
pathways, regardless of which eye was damage in glaucoma. Servais et al8 said
Ø Generated automatically by the affected. that by accurately quantifying the RAPD
device. additional information can be provided,
In a study conducted on Indian which may aid management-for example,
Ø Index of the direction and magnitude eyes at our centre (unpublished data) of assessing retinal ischaemia following
of pupil response asymmetry. normal subjects in the age group of 18 – central retinal vein occlusion.
60 years, the RAPD amplitudes for full-
Ø Formula: Difference in the amplitude field on stimulation with white light were Hence, RAPD is a clinical sign that,
of pupil constriction between 0.07±0.21 log units; the corresponding when abnormal, is one of the best ways
stimulation of the two eyes. figures for stimulation with red light were to localize vision loss to the anterior
RAPD score = 10*log10 (OD/OS) 0.27±0.60 log units, green 0.16±0.38 log afferent visual pathways (retina, optic
Where, OD is the mean response units, blue 0.27±0.54 log units and yellow nerve, chiasm) and quantification of the
0.12±0.42 log units, respectively. The same by novel techniques such as RAPDx
amplitude in both eyes, in response to RAPD latencies on stimulation with white will enable earlier diagnosis of disease
right eye stimulation light full field stimulus were 0.15±0.14 and thereby earlier management.
log values. Increase in the log values of
OS is the mean response amplitude latency was seen as the age advances.
in both eyes in response to left eye
stimulation. Tatham AJ et al2,7 found a good
The RAPD score is useful as it
confers information regarding the
direction as well as the magnitude of an
References 6. Yotharak P, Aui-Aree N. Correlation between clinical grading
and quantification by neutral density filter of relative afferent
1. Law CL, Siu M, Modica P, Backus B. Stimulus characteristics pupillary defect (RAPD). J Med Assoc Thail Chotmaihet
affect assessment of pupil defects in amblyopia. Optom Vis Sci Thangphaet. 2012;95 Suppl 4:S92-S95.
Off Publ Am Acad Optom. 2015;92:551-58.
7. Tatham AJ, Meira-Freitas D, Weinreb RN, Marvasti AH, Zangwill
2. Tatham AJ, Meira-Freitas D, Weinreb RN, Zangwill LM, Medeiros LM, Medeiros FA. Estimation of retinal ganglion cell loss in
FA. Detecting glaucoma using automated pupillography. glaucomatous eyes with a relative afferent pupillary defect.
Ophthalmology. 2014;121:1185-93. Invest Ophthalmol Vis Sci. 2014;55:513-22.
3. Cohen LM, Rosenberg MA, Tanna AP, Volpe NJ. A Novel 8. Servais GE, Thompson HS, Hayreh SS. Relative afferent pupillary
Computerized Portable Pupillometer Detects and Quantifies defect in central retinal vein occlusion. Ophthalmology.
Relative Afferent Pupillary Defects. Curr Eye Res. 2015;6:1-8. 1986;93:301-03.
4. Kawasaki AK. Diagnostic approach to pupillary
abnormalities. Contin Minneap Minn. 2014;20 (4 Neuro-
ophthalmology):1008-1022.
5. Bell RA, Waggoner PM, Boyd WM, Akers RE, Yee CE. Clinical
grading of relative afferent pupillary defects. Arch Ophthalmol
Chic Ill 1960. 1993;111:938-942.
Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
www. dosonline.org 43
SNAPSHOT
Ocular Decompression Retinopathy
Rakhi Kusumesh
Dr. Rakhi Kusumesh
Assistant Professor
Regional Institute of Ophthalmology
Indira Gandhi Institute of Medical Sciences, Patna, Bihar
Ocular decompression retinopathy (ODR) is
defined as a multifocal hemorrhagic retinopathy
that results from acute lowering of intraocular
pressure (IOP). In 1965, Paufique et al reported
a patient with retinal hemorrhages following
medical treatment for acute angle closure
glaucoma; however they could not make a specific diagnosis,
and suspected the retinal hemorrhages were related to
the rapid lowering of the IOP1. In 1992, Fechtner first time Figure 1: Diffuse and well-elevated bleb on first postoperative day
described this retinopathy as a complication following (18-year-old male underwent trabeculectomy with mitomycin C for
angle recession glaucoma right eye).
trabeculectomy and coined the term Ocular decompression
retinopathy2. Although ODR infrequently results in significant
ocular morbidity, gradual reduction in IOP might prevent this intraoperative IOP, phacoemulsification with posterior capsule
complication. Outcome of decompression retinopathy is good rupture with coexistent POAG, posterior segment surgeries,
with spontaneous resolution in a matter of weeks.
and even medical treatment of elevated IOP can give rise to
Etiopathology decompression retinopathy4-9. But trabeculectomy is cited as
the most common cause of ODR (Figure 1).
The mechanism of decompression retinopathy remains
unclear, but its occurrence after glaucoma filtration surgery Clinical features
suggests that a sudden lowering of IOP may lead to increased Most of the patients with ODR are usually asymptomatic.
ocular blood flow, resulting in disruption of the mechanical Very small proportion patients have the symptom of floaters,
stability of the capillaries and cause focal capillary leakage. central scotoma and decreased vision. Usually ODR develops in
one eye; however fellow eye involvement was reported in few
Autoregulation allows retinal capillaries to maintain a cases. Mukkamala et al reported the mean decrease in IOP of
constant perfusion pressure across a wide range of systemic 33.2 ± 15.8mmHg following surgery and mean time to diagnosis
arterial blood pressures and IOPs. Extended periods of elevated was 1.5 ± 2.0 days9.
IOP, as in primary open-angle glaucoma, may cause a loss of
retinal autoregulation. Fechtner et al. proposed the vascular Fundus examination demonstrates intraretinal
theory that defective autoregulation of blood vessels because hemorrhages which can occur
of longstanding glaucoma Ocular decompression retinopathy in all retinal layers throughout
(ODR) is defined as a multifocal the fundus; most commonly
and hypotony result sudden hemorrhagic retinopathy that results in the peripapillary area and
within the posterior fundus
increase in retinal intravascular which can extend to peripheral
flow and, consequently leading
to retinal hemorrhages2,3. In
addition, an acute decrease in from acute lowering of intraocular retina2. White-centered
IOP can result an anterior shift pressure (IOP) hemorrhages are seen in 20%
and forward displacement of cases10. Although subhyaloid
the lamina cribrosa, causing and vitreous hemorrhages are
blockage of axonal transport leading to compression of the uncommon but can be visually disabling (Figure 2 a,b). Few
central retinal vein and retinal hemorrhages mimicking retinal cases of ODR can have peripapillary and optic nerve head
vein thrombosis, has been suggested as an another possible hemorrhages with or without disc hyperemia and edema.
mechanism4. Rarely some atypical features such as choroidal detachment
In majority of the cases, IOP-lowering procedures are and a serous retinal detachment can be found11.
considered to be the most common etiology associated with Fluorescein angiography demonstrates blocked fluore-
ODR. Other procedures including glaucoma drainage implant scence consistent with the retinal hemorrhages seen on
insertions, trabeculotomy, iridotomy, iridoplasty, anterior funduscopic examination (Figure 3 a,b). Most of the patients
have normal retinal and choroidal vascular filling; it helps
chamber paracentesis, orbital decompression surgery
with reduction in retrobulbar pressure and fluctuation in to distinguish ODR from other conditions associated with
www. dos-times.org 45
SNAPSHOT (b)
(a)
Figure 2 (a)&(b): Depicts fundus photograph showing diffuse retinal hemorrhages (a) and subhyaloid hemorrhages (b).
(a) (b)
Figure 3(a)&(b): Depicting the fundus fluorescein angiogram showing multiple, blocked fluorescence due to the retinal hemorrhages, but the vascular
filling appears normal
intraretinal hemorrhages the sudden decompression;
sufficient control of IOP before
conditions including Central the glaucoma surgery, slow
drainage of aqueous humor
retinal vein occlusion (CRVO), through the paracentesis and
its immediate replacement
Valsalva retinopathy, Terson with viscoelastic material
in the anterior chamber to
syndrome, shaken baby allow gradual lowering of IOP,
and tight closure of the flap
syndrome, and diabetic with releasable sutures to
prevent marked and prolonged
retinopathy. On the contrary hypotony12.
to acute CRVO, ODR have no The course of
decompression retinopathy is
evidence of venous dilatation usually benign with complete
resolution of the hemorrhages
and delayed venous filling in (Figure 4). Mukkamala et al.
fluorescein angiography5. found the average resolution
Acute reductions of IOP
during surgery and hypotony in
the early postoperative period
trigger retinal hemorrhages.
Therefore, few careful
measures should be taken into
account preoperatively and Figure 4: depicting fundus photograph showing resolving subhyaloid
hemorrhage
intraoperatively to prevent
46 DOS Times - July-August 2015
SNAPSHOT
time is 13 ± 12.4 weeks (2 weeks to Complications of glaucoma surgery. phacotrabeculectomy. Differential
72 weeks) with complete recovery of
visual acuity9. In most of the patients, no Ocular decompression retinopathy. diagnosis. Arch Soc Esp Oftalmol.
intervention is required but vitrectomy
may be required to remove a visually Arch Ophthalmol 1992; 110: 965-68. 2001;76:509-10
significant, non-resolving vitreous or pre-
retinal hemorrhage. 3. Grieshaber MC, Mozaffarieh 8. Juberias JR, Maquet JA, Ussa F.
In conclusion, ocular decompression M, Flammer J. What is the link Decompression retinopathy with
retinopathy is an unusual self resolving
complication arising from an acute between vascular dysregulation maculopathy after trabeculectomy
decrease in IOP. This condition should be
anticipated after IOP lowering procedure and glaucoma? Surv. Ophthalmol. with mitomycin C. Arch Soc Esp
for cases with rise of IOP over an
extended period. Therefore, precautions 2007;52:S144-54. Oftalmol. 2008; 83:373-6
should be taken to reduce the risk of this
complication. 4. Lee EJ, Kim TW, Weinreb RN. Reversal 9. Mukkamala SK, Patel A, Dorairaj S.
References of lamina cribrosa displacement Ocular decompression retinopathy:
1. Paufique L, Ravault MP, Malterre and thickness after trabeculectomy a review. Surv Ophthalmol. 2013;
M, et al. Retinal hemorrhage after
medical sedation of an attack of in glaucoma. Ophthalmology. 58:505-12.
acute glaucoma. Bull Soc Ophtalmol
Fr. 1965;65:1105-8. 2012;119:1359-66. 10. Gupta R, Browning AC, Amoaku
2. Fechtner RD, Minckler D, Weinreb 5. Lee SJ, Lee JJ, Kim SD. Multiple retinal WM. Multiple retinal haemorrhages
RN, Frangei G, Jampol LM.
hemorrhage following anterior (decompression retinopathy)
chamber paracentesis in uveitic following paracentesis for macular
glaucoma. Korean J Ophthalmol. branch artery occlusion. Eye.
2006;20:128-30. 2005;19:592-3.
6. Mandal AK, Jalali S, Rao VS, et 11. Nonoyama S, Tanito M, Katsube T,
al. Valsalva retinopathylikem et al.decompression retinopathy
hemorrhage associated with and serous retinal detachment
combined trabeculotomy- after trabeculectomy in a patient
trabeculectomy in a patient with systemic amyloidosis. Jpn J
with developmental glaucoma. Ophthalmol. 2009; 53:73-5.
Ophthalmic Surg Lasers. 12. Jea SY, Jung JH. Decompression
2001;32:330-2. Retinopathy after Trabeculectomy.
7. Castejon MA, Fagundez MA, Perez P, Korean J Ophthalmol. 2005;19:128-
et al. Retinal hemorrhages following 31.
Financial Interest: The author do not have any financial interest in any procedure/product mentioned in this manuscript.
www. dos-times.org 47
INNOVATIONS
Pupil Expansion Redefined with
Bhattacharjee Ring
Suven Bhattacharjee
generated clear corneal incisions (CCIs) have significantly
Dr. Suven Bhattacharjee MS, DO, DNB lower endothelial gaping, endothelial misalignment, Descemet
Nayan Eye Associates, Complete Care membrane detachment, and posterior wound retraction
Lake Road, Kolkata, India than keratome-created CCIs10. Adequate pupil dilation is a
prerequisite for imaging and treatment in FLACS1. Applanation
Small-pupil cataract surgery is surgically challenging with the patient interface may slightly decrease pupil size. In
because of co-morbidities and is associated with
higher complication rates1. In addition, small pupils addition, application of laser energy induces further pupillary
may lead to smaller than desired capsulotomy
diameters, causing capsule contracture and a miosis, sometimes resulting in a pupil constricting more than
posterior shift of the implanted IOL1.
The known causes of poorly dilating pupil are - intra 2.0 to 3.0 mm between applanation with the patient interface
and initiation of phacoemulsification9. For FLACS in small pupil
eyes, a manual 2.2 mm or larger incision and two side port
incisions used to insert a ring, not only deny the patient the
benefit of superior Femtosecond laser–generated clear corneal
operative Floppy Iris Syndrome (IFIS), diabetes, uveitis, senility, incisions but also expose the eye to increased risk of anterior
pseudoexfoliation, prolonged miotic use, posterior synechiae,
prior intraocular surgery etc. Eyes with preoperative dilated chamber shallowing, infection and inflammation1,10.
In FLACS, if significant pupillary miosis is noted following
pupil diameter of 7.0 mm or smaller, are at risk for IFIS regardless laser application, if a Malyugin ring is placed after the laser
of α-1 adrenergic receptor antagonist (ARA) treatment2. treatment has been completed, one must be careful not to
While Chang and Campbell reported a 2.3% incidence of incorporate the edge of the anterior capsule under the ring
IFIS in a cataract surgery population3, the incidence in literature as this may induce an anterior capsule tear9. The microscope
has been variably reported to be between 0.9 and 3.7%4,5. provides a top view of the Malyugin ring and the side facing
Recently Goyal et al have reported gaps are not clearly visible. The gaps
an incidence of 4.78 % in Indian Disposable square in the scrolls are on the sides of the
population, which is much higher than
and device and are not directly visible.
the reported global incidence of IFIS6. hexagonal Bhattacharjee pupil- This increases the risk of catching the
In the 2008 ASCRS IFIS survey, capsule edge in the scrolls.
95% of experienced surgeons reported expansion rings are made of As biaxial and coaxial MICS
that systemic treatment with the 5-0 nylon, have notches at the are prevalent techniques and are
α1- ARA, Tamsulosin makes cataract corners, and flanges at the performed through incisions equal to
surgery more difficult and leads to sides in a single 0.1 mm thin or smaller than 1.5 mm and 2.0 mm
respectively, there is a need for pupil-
higher rates of complications7. Overall
expansion rings that can be inserted
complication rate in IFIS group in an plane. This simple single plane
Indian population was reported to be through such microincisions8.
6.25%, and was significantly higher design of the Bhattacharjee ring
than the non-IFIS group6. (patent pending) redefines the Even during 2.2 mm micro coaxial
way pupil is expanded phacoemulsification or 2.8 mm
The Unmet Need standard coaxial phacoemulsification,
a device that could be inserted
The increasing incidence of comfortably through a smaller wound
IFIS, serious complications associated with IFIS and growing would be an advantage8. For 23-gauge or 25-gauge micro
demand for perfect visual outcomes, have all added up to reduce
the surgeons threshold for using a pupil expansion device. incision vitreous surgery (MIVS) in small-pupil eyes, a 2.2
With any incision size chosen for phacoemulsification, in the
presence of progressive intraoperative miosis and iris prolapse mm corneal incision merely to place a pupil expansion ring is
associated with IFIS, it would be desirable to use a smaller 0.9 undesirably large and self-defeating8.
mm side-port incision to place a pupil-expansion ring8.
The estimated vertical profile of the Malyugin ring at the
Femtosecond laser–assisted cataract surgery (FLACS) corners, inclusive of 2 strands of the coiled 4-0 polypropylene
provides surgeons an exciting new option to potentially (Prolene) and the bunched-up iris, is 0.7 to 0.9 mm8. The
improve patient outcomes and safety9. Femtosecond laser– vertical height of the scrolls is significant in the presence of
a shallow anterior chamber because the scrolls occupy the
mid-peripheral anterior chamber, which is shallower than the
central part8.
www. dos-times.org 49
INNOVATIONS
Pupil Expansion Redefined Figure 1: Bhattacharjee Rings, Square and Hexagon.
This simple single plane design of Figure 2: Special 23 G Forceps with wide jaws used to insert and engage a hexagonal Bhattacharjee
the Bhattacharjee ring (patent pending) ring through a single 20G incision.
redefines the way pupil is expanded8.
Disposable square and hexagonal The clear corneal incision is a self- Bimanual MICS, the Bhattacharjee ring is
Bhattacharjee pupil-expansion rings sealing slit. Bi-planar structures at the the only available option14 (Figure 5).
are made of 5-0 nylon, have notches at corners of a pupil expansion device
the corners, and flanges at the sides in snag the slit corneal incision during The bi-planar structures at the
a single 0.1 mm thin plane8 (Figure 1). entry and exit. The Malyugin ring can corners increase the vertical profile of
A flange is held with a 23-gauge forceps snag the incision or the injector cannula the device, which may range from 0.9-1.2
and the ring is inserted through a 0.9 during removal because of the gap in mm. When such a device is placed in the
mm (20-gauge) or larger main or side- the bi-planar helical coil8,15. Hence, it anterior chamber on the surface of the
port incision (Figure 2 & 3). Alternate is necessary to deliver and remove the iris, the corners lie at the mid-periphery
flanges are tucked under the iris using Malyugin ring, Oasis Iris expander and of the anterior chamber which is much
a Kuglen hook or 23-gauge forceps. The Xpand Iris speculum using an injector or shallower than the central anterior
ring is removed by disengaging 2 notches cartridge mechanism. The injector tube chamber. This could be very critical in eyes
and pulling it out of a 0.9 mm (20-gauge) or nozzle of the cartridge requires at least with shallow anterior chambers. The 0.1
incision (Figure 4) No snagging of the a 2.2 mm incision. The Bhattacharjee ring mm vertical profile of the Bhattacharjee
incision occurs at insertion or removal. has single plane notches at the corners ring makes pupil expansion safe even in
No injector is required8. which straighten as the device is carried eyes with extremely shallow anterior
through a 0.9 mm incision with a 23 gauge chambers8. The thin profile of the device
The Malyugin Ring is a foldable and forceps, without any snagging. Thus also allows unhindered movement of the
disposable square pupil-expansion device the need for an injector is completely Phaco probe and side-port instruments
made of 4-0 polypropylene and has 4 eliminated. Among presently available (Figure 6).
circular coils or scrolls at the corners that pupil expansion devices, for 1.8 mm
engage the pupil edge to expand it11. The coaxial MICS a wound assisted technique Looking through the microscope
Oasis Iris Expander is also a disposable for the Malyugin ring may be used but for provides a top view of the Malyugin ring,
square pupil-expansion device made of incisions smaller than that or sub 1.5 mm Oasis Iris expander, Xpand Iris speculum
polypropylene and has 4 pockets at the and Bhattacharjee ring. The gaps in the
corners that engage the pupil edge12. The scrolls or pockets are on the sides of
Xpand Iris Speculum has 4 speculum like
feet which form pockets which have a
height of 1.2 mm13.
In all these devices, the pupil margin
engaging part or gap (scrolls, pockets
or speculum like feet) straddles across
the pupil margin either obliquely or
perpendicularly and has an upper part
and a lower part making this part actually
a bi-planar structure. The space or gap
that receives the pupil margin is oriented
either perpendicular or oblique to the
principal plane of the device. The device
does not bend the pupil margin and the
adjacent iris at the area of engagement.
The Bhattacharjee ring uses a
radically different concept to engage the
pupil margin. Bringing all the bends at the
corners to a single plane in turn brings
the supporting elements also to a single
plane, and effectively brings the entire
device to a single plane and reduces
the vertical profile. The different way in
which the pupil margin engaging part of
the device engages the pupil margin, is
the inventive step. Since the pupil margin
engaging part of the Bhattacharjee ring is
in the same plane as the device, it bends
the pupil margin and the adjacent iris at
the area of engagement. The pupil margin
straddles across the plane of the device
whereas in all prior devices a part of the
device straddles across the plane of the
pupil margin.
50 DOS Times - July-August 2015
INNOVATIONS
vice versa. When the Malyugin device is
deformed, the scrolls can unpredictably
crush or release the pupil margin. The
pockets at the corners of the Oasis Iris
expander or Xpand iris speculum do not
engage the pupil margin very securely
and it may slip out. The simple notches
of the Bhattacharjee ring engage the
pupil margin securely, reversibly and
atraumatically. This is evidenced by the
round unharmed pupil after removal of
the device. The simple notches also allow
a fair amount of rotation of the device
without damaging the pupil margin. This
feature greatly facilitates tucking of all
the flanges with a 23 gauge forceps and
expansion of the pupil with a single 0.9 –
1.0 mm incision.
Figure 3: Standard 23 G Forceps used to insert and engage a hexagonal Bhattacharjee ring through Does Shape matter?
a 2.2 mm main incision and two 0.9 mm side-port incisions.
Yes, it does. Geometrically, a
Figure 4: Removal of a hexagonal ring through a 20G side-port incision and the round pupil hexagonal shape has advantages over
suggesting an atraumatic engagement of the pupil margin. a square shaped pupil expansion
device17,18,19.
the device and are not directly visible. A pupil expansion device should
Aligning these gaps to the pupillary engage the pupil margin securely When deformed and delivered
margin is difficult. As the Bhattacharjee and reversibly but atraumatically. into anterior chamber through a small
ring is in a single plane, the gaps or The scrolls of the Malyugin ring are incision or when deformed in the anterior
notches that engage the pupil margin are essentially torsional springs that provide chamber to engage or disengage the
directly visible from a top view8. This is springiness at the corners8,16. Because of pupillary margin a square device is much
very helpful in not engaging the capsule the gap between the coils of a torsional longer than a hexagon. A longer device
margin when the device is deployed spring, it acts as a compression spring in the anterior chamber is more likely
after the capsulorhexis has been created too, with narrowing of the gap as the to cause damage to the endothelium, iris
(Figure 7). arms are moved toward each other and and angle. Let’s illustrate this with an
example. To create a 5 mm capsulorhexis,
we require a 6 mm pupil. A 6 mm ‘incircle’
is contained within a square with 6 mm
sides (Figure 8). When deformed the
longest diagonal of such a square would
be; 6 mm x 2 = 12 mm. A 6 mm incircle
is contained within a regular hexagon
with 3.46 mm sides17,18 (Figure 9). When
deformed the longest diagonal of such a
hexagon would be; 3.46 mm x 3 = 10.38
mm. Hence, the hexagon is less likely to
Figure 5: Bimanual 1.4 mm MICS after expanding the pupil with a Figure 6: 2.2 mm Phacoemulsification and the Bhattacharjee ring
Bhattacharjee square device. allowing unhindered movement of instruments.
www. dos-times.org 51
INNOVATIONS
Figure 7: Easily visible notches from a top view help in not engaging the capsulorhexis edge. incircle, the hexagon requires a smaller
circumcircle than the square8,17,18,19. Hence,
cause collateral damage when deformed Does Size matter? a larger hexagon can be accommodated
within the anterior chamber. in a given anterior chamber, resulting in a
Yes, it does. The size of a pupil larger pupil. It also implies that a hexagon
If the size of the device is a measure expansion ring device is essentially a would provide a larger pupil compared
of the distance between two opposite measure of the distance between two to the same sized square. A hexagonal
sides, a hexagonal device provides larger opposite sides. It is important to note device would be preferred for smaller
expansion of pupil compared to a same that the size of the device does not anterior chambers and would cause less
size square device. As in the example reflect the size of the expanded pupil. injury to cornea, iris and angle. A smaller
above, a 6 mm incircle is contained within The pupil margin is received into the hexagonal device also causes less stretch
a square with 6 mm sides and also a 6 scrolls, pockets and notches. Hence, the and damage to the sphincter and would
mm incircle is contained within a regular expanded pupil is usually smaller than result in a round pupil postoperatively.
hexagon with 3.46 mm sides. (Figure 8 the external size of the device. It would be Hence, the size of the anterior chamber
& 9) A Square with an Incircle of 6 mm useful if the package of a pupil expansion should be an important consideration in
lies within an 8.48 mm Circumcircle17,19 device indicated the actual size of the choosing the appropriate ring. There is
(Figure 10). A hexagon with an incircle expanded pupil in addition to the external poor agreement and a weak correlation
between the horizontal white to white
dimensions of the device. (WTW) corneal diameter and the ciliary
sulcus or anterior chamber diameter,
although, there is statistically significant
linear correlation20. This linear correlation
was useful in formulating a nomogram
for choosing the Bhattacharjee ring size
based on the horizontal WTW corneal
diameter8. A similar nomogram provided
on the package for every pupil expansion
device would be useful. In a study it has
also been recommended that the device
size be chosen preferably on the basis of
a nomogram and not the hardness of the
cataract17. Instead of choosing a larger
device, a hard cataract may be chopped
or divided into smaller fragments to
increase safety17.
Figure 8: Square with 6 mm incircle. A large device placed and The Delivery system
manipulated inside a small anterior
Figure 9: Hexagon with 6 mm incircle. chamber could cause significant collateral During the development of the
of 6 mm lies within an 6.92 mm damage. A Square with an Incircle of 6 Bhattacharjee ring it was realized that
Circumcircle18. Hence, for a desired mm, lies within an 8.48 mm Circumcircle. to insert the device through a 0.9 mm
pupil size, a smaller hexagon is required A hexagon with an Incircle of 6 mm, incision, the injector-cartridge system
compared to a square. Thus in a small eye lies within a 6.92 mm ‘Circumcircle’. had to be dispensed with. The walls of the
a hexagonal device is preferred. A smaller For a given size of capsulorhexis as an delivery tube of an injector/ cartridge are
hexagonal device causes less stretch and wasted space and unnecessarily require
damage to sphincter resulting in round an incision to be larger. A special 23
pupils in the post-operative period. gauge microsurgical forceps with wide
jaws is used to insert, engage and remove
the device through a single 0.9–1.0 mm
incision. However, a regular 23 gauge
microsurgical forceps may be used for
a regular 2.2 mm phacoemulsification
and two side-ports. Today, the averagely
skilled cataract surgeon is very
comfortable using a 23 gauge forceps
in the anterior chamber and hence an
injector-cartridge system is unnecessary.
A wound assisted delivery could insert
the Bhattacharjee ring even through a 0.5
mm incision.
Present status
The Bhattacharjee rings have been
successfully used in clinical trials in 10
52 DOS Times - July-August 2015
INNOVATIONS
Figure 10: Circumcircle of a square with 6 mm incircle and hexagon with 6 mm incircle. 11. Microsurgical Technology. MST
Malyugin ring. Available: http://
centres in Europe and Asia for standard Khiun Tjia, Dr. Ronald Yeoh, Dr. Sheraz www.microsurgical.com/products/
2.2 mm coaxial phacoemulsification, Daya, Dr. Arup Bhaumik, Dr. Kasu Prasad malyugin-ring/6-25mm-malyugin-
bimanual MICS, FLACS, shallow anterior Reddy, Prof. Sri Ganesh and Dr. Jean- ring. Accessed 24th May 2015.
Luc Febbraro)8,14. The device is not yet
chambers and intraoperative miosis commercially available. 12. Oasis Medical. Oasis Iris Expander.
Available: http://oasismedical.com/
(Personal communications: Prof. H oasis-iris-expander.html. Accessed
24th May 2015.
Burkhard Dick, Prof. Jorge Alio, Dr.
13. Diamatrix Ltd. Xpand Iris Speculum.
References 6. Goyal S, Dalela D, Goyal NK1, Chawla Available: http://www.xpand-iris-
S, Dhesi R, Kamboj B, Dalela A. speculum.com/pdf/xpandppt.pdf.
1. Conrad-Hengerer I, Hengerer FH, Intraoperative floppy iris syndrome Accessed 24th May, 2015.
Schultz T, Dick HB. Femtosecond in Indian population: a prospective
laser–assisted cataract surgery in study on incidence, risk factors, and 14. Bhattacharjee S. Pupil expansion
eyes with a small pupil: J Cataract impact on operative performance. devices for MICS. Ophthalmology
Refract Surg. 2013;39:1314-20. Indian J Ophthalmol. 2014;62:870-5. Times Europe. Nov 2014;10:18-22.
2. Casuccio A, Cillino G, Pavone C, 7. Chang DF, Braga-Mele R, Mamalis 15. Rauen M, Oetting T. Partial retraction
Spitale E, Cillino S. Pharmacologic N et al. Clinical experience with of Malyugin pupil expansion device to
pupil dilation as a predictive test for intraoperative floppy-iris syndrome; improve safety during ring removal. J
the risk for Intraoperative floppy-iris results of the 2008 ASCRS member Cataract Refract Surg 2010; 36:522–
syndrome; J Cataract Refract Surg survey. J Cataract Refract Surg. 23
2011; 37:1447–54. 2008;34:1201–09.
16. Wright D. Springs. School of
3. Chang DF, Campbell JR: Intraoperative 8. Bhattacharjee S. Pupil-expansion Mechanical and Chemical
floppy iris syndrome associated with ring implantation through a 0.9 mm Engineering, University of Western
tamsulosin. J Cataract Refract Surg incision. J Cataract Refract Surg. Australia, 2005. Available at: http://
2005; 31:664–73. 2014; 40:1061–67. school.mech.uwa.edu.au/~dwright/
DANotes/springs/intro/intro.html.
4. Neff KD, Sandoval HP, Fernández de 9. Donaldson KE, Braga-Mele R, Cabot Accessed 24th May, 2015.
Castro LE, Nowacki AS, Vroman DT, F, Davidson R, Dhaliwal DK, Hamilton
Solomon KD. Factors associated with R, et al. Femtosecond laser–assisted 17. Bhattacharjee S. Does size and
intraoperative floppy iris syndrome. cataract surgery. J Cataract Refract shape matter for pupil expansion
Ophthalmology 2009;116:658-63. Surg 2013; 39:1753–63. rings? Poster presented at the XXXII
Congress of the European Society of
5. Bell CM, Hatch WV, Fischer HD, Cernat 10. Grewal D S, Basti S. Comparison of Cataract and Refractive Surgeons,
G, Paterson JM, Gruneir A, et al. morphologic features of clear corneal London, UK, September 2014.
Association between tamsulosin and incisions created with a femtosecond Available at: http://www.escrs.org/
serious ophthalmic adverse events in laser or a keratome. J Cataract Refract london2014/programme/posters-
older men following cataract surgery. Surg 2014; 40:521–30. details.asp?id=20248. Accessed 24th
JAMA 2009;301:1991-6. May, 2015.
18. Geometric Calculators: Hexagon
Calculator. Rechneronline; Available
at: http://rechneronline.de/pi/
hexagon.php. Accessed 24th May,
2015.
19. Math Open Reference. Circumcircle
of a Polygon. Available at:
h t t p : / / w w w. m a t h o p e n r e f . c o m /
polygoncircumcircle.html. Accessed
24th May, 2015.
20. Kawamorita T, Uozato H et. al.
Relationship between ciliary sulcus
diameter and anterior chamber
diameter and corneal diameter. J
Cataract Refract Surg 2010; 36:617-
24.
Financial Interest: The author does not have any financial interest in any procedure/product mentioned in this manuscript.
www. dos-times.org 53
Monthly meeting korner
Corneal Collagen Cross-Linking with Smile Lenticule:A New
Modality ofTreatment for the Ultrathin Keratoconic Cornea
Ritika Sachdev, Gitansha Sachdev, Deepa Gupta, Mahipal Sachdev
Corneal collagen cross-linking or CXL is a promising treatment modality to
increase the mechanical and biochemical strength of the corneal tissue
Keratoconus is a non inflammatory, progressive intraoperative pachymetry to determine the thickness of the
ectatic disorder of the cornea. Impaired visual refractive lenticule to be placed for tailored stromal expansion.
acuity results from progressive myopia, irregular
astigmatism and central corneal scarring. The refractive lenticule required for the procedure is
Treatment modalities described in various stages obtained from patients undergoing small incision lenticule
of the disease process include spectacles, contact extraction (SMILE) for myopic correction. The visumax
femtosecond laser system is used to perform small incision
lenses, intrastromal corneal ring segments, corneal collagen lenticule extraction. The laser is used to cut a refractive lenticule
cross linking and lamellar and penetrating keratoplasty. intrastromally, the thickness of which is determined by the
Corneal collagen cross-linking or CXL is a promising desired refractive correction. The lenticule is then separated
treatment modality to increase the mechanical and biochemical manually from the overlying flap and underlying stromal bed.
strength of the corneal tissue1-2. Using UVA radiation at 370 nm The separated lenticule is extracted from the stroma through
and photosensitizer riboflavin, the photosensitizer is excited a 3mm corneal incision. The lenticule procured is thickest at
into its triplet state generating reactive oxygen species. These the centre and thinner peripherally. Hence the placement of the
reactive oxygen species create additional chemical bonds in lenticule is such that the central portion of the lenticule overlies
the corneal stroma by polymerization, increasing the tensile the thinnest area of the cone.
strength of the cornea. The augmented stromal thickness is measured using
Based on the current protocol for performing CXL, the intraoperative pachymetry and a thickness of more than 400
cross linking effect is limited to the anterior 300 microns of
the corneal stroma.. A corneal thickness of 400 microns is microns is confirmed, allowing CXL to be performed within the
considered as the safe limit to protect the endothelium and required safety protocol guidelines. 1 drop of isotonic riboflavin
(0.1 % solution of 10mg riboflavin 1 phosphate) is instilled every
intraocular structures from the adverse effects of UV irradiation 5 minutes for 30 minutes. Slit lamp examination is performed
and has been established as a clinical standard3. to confirm the presence of yellow flare in the anterior chamber
Unfortunately, the very patients who are in need of CXL and ascertain adequate penetration of the dye. UVA radiations
have thin corneas often below the threshold of that considered of 365nm with desired irradiance of 3mW/cm2 are used at a
to be safe for the treatment. In developing countries of the Asian distance of 5 cm. Riboflavin drops are instilled every 5 minutes
sub-continent such as ours, keratoconus
has an earlier onset and is often detected
at a later stage making the disease not
amenable to traditional CXL4.
Currently available treatment
modalities for CXL in thin corneas include
hypoosmolar riboflavin, contact lens
assisted CXL and transepithelial CXL5-9.
However these procedures have their own
limitations.
We describe a new and innovative
procedure to increase the intraoperative
corneal thickness using refractive
lenticules of patients undergoing small
incision femtosecond lenticule extraction
for myopic correction.
Technique: The procedure is carried
out under topical anaesthesia. Central 8
mm of the corneal epithelium is debrided
using a blunt spatula. The thickness of the Figure 1: showing the ASOCT image after the placement of stromal lenticule and initial riboflavin
remaining stromal bed is measured using soakage
www. dos-times.org 55
Monthly meeting korner
Results for the next 30 minutes. Throughout the
Table 1: Patient Data procedure the lenticule remains firmly
attached offering a physiological increase
S.No. Patient Kmax Kmax (6 Preoperative Epithelium in the intraoperative stromal thickness as
Details (preoperative months thinnest off stromal seen on anterior segment OCT (Figure 1).
postoperative) pachymetry thickness
1 18 Y/F (in microns) (in microns) On completion of the procedure
2 20 Y/M 56.2/58.4 55.1/57.8 394 326 the refractive lenticule is peeled off the
3 24 Y/F 45.1/49.6 44.0/49.4 408 354 stromal bed and the surface is irrigated
4 19 Y/M 45.2/50.8 44.7/50.2 402 337 with normal saline. A bandage contact
5 25 Y/M 48.4/52.1 48.1/51.5 386 324 lens is applied which is removed on the
6 22 Y/F 51.3/56.8 50.1/54.4 376 321 fifth postoperative day.
7 26 Y/F 54.1/58.7 52.4/56.7 414 367
56.6/49.8 55.1/47.2 423 382 This procedure was performed in 7
eyes of progressive keratoconus (Table 1)
Figure 3: Showing the CXL induced demarcation line with a stromal corneal thickness of less
than 400 microns and a best corrected
Preoperative and six month postoperative refractive map on pentacam visual acuity of more than 6/9 with contact
Figure 2: showing the preoperative and six month postoperative refractive topography map lenses. No intraoperative complications
(PENTACAM) were noted in any of the patients. Corneal
stability was diagnosed on topography
at 6 months follow up (Figure 2). No
significant endothelial cell loss was noted
in any of the cases. Presence of stromal
haze and its resolution was similar to that
of conventional CXL. A clear demarcation
line at a depth ranging from 280 to 310
microns was noted in all the patients
(Figure 3).
Our technique overcomes many of
the demerits of the earlier techniques of
crosslinking the thin cornea and can be
used in both traditional and accelerated
crosslinking modalities.
Hypoosmolar CXL describes the
instillation of hypotonic riboflavin to
increase the hydration of the cornea
and hence the thickness. Increased
intraoperative time, and a relative lower
concentration of collagen in the hydrated
stroma are some of the limitations of this
technique.
Contact lens assisted CXL involves
placement of a soft contact lens to increase
the corneal thickness intraoperatively.
However the biomechanical properties
of a contact lens differ from that of
the corneal stroma. Moreover the
thickness of the contact lens placed is
constant and cannot be customised.
Additionally buckling of the contact
lens intraoperatively can result in an
uneven pre-corneal riboflavin layer with
subsequent hot and cold spots.
Centre For Sight, Safdarjung Enclave, New Delhi, India
Dr. Ritika Sachdev MS Dr. Gitansha Sachdev MS, FICO Dr. Deepa Gupta MS Dr. Mahipal Sachdev MD
56 DOS Times - July-August 2015
In our modified technique of CXL patients with advanced keratoconus, Monthly meeting korner
using the refractive lenticule, thickness who have useful vision with
of the cornea is increased in the most contact lenses. Crosslinking these Sanford-Smith JH. “does ethnic origin
physiological manner by adding stromal patients, offers them the possibility influence the incidence or severity of
tissue whose biological and absorptive of maintaining their vision and keratoconus ’’ Eye 2000;14:625-8
properties are the same as that of potentially avoiding a future corneal 5. Hafezi F, Mrochen M, Iseli HP, Seiler T.
the cornea to be treated. Refractive transplantation. Collagen crosslinking with ultraviolet-A
lenticules of variable thickness (20 to and hypoosmolar riboflavin solution in
140 microns) can be obtained following References thin corneas. J Cataract Refract Surg
FLE depending on the extent of refractive 2009;35:621-4.
error to be corrected. Placement of the 1. Wollensak G, Spoerl E, Seiler T. 6. Filippello M, Stagni E, O’Brart D.
central lenticule over the apex of the Riboflavin/ultraviolet-A-induced Transepithelial corneal collagen
cone enables us to augument the corneal collagen crosslinking for the treatment crosslinking: Bilateral study. J Cataract
thickness where required while sparing of keratoconus. Am J Ophthalmol Refract Surg. 2012;38:283-91.
the remaining stroma to be crosslinked 2003;135:620-7. 7. Spadea L, Mencucci R. Transepithelial
normally. Moreover, the relatively rough corneal collagen crosslinking in
host stromal surface allows the lenticule 2. Spoerl E, Mrochen M, Sliney D, Trokel ultrathin keratoconic corneas.
to spread easily and buckling is avoided. S, Seiler T. Safety of UVA-riboflavin ClinOphthalmol. 2012;6:1785-92.
cross-linking of the cornea. Cornea 8. Kymionis GD, Diakonis VF,
In conclusion, our modified 2007;26:385-9. Coskunseven E, Jankov M, Yoo SH,
technique of tailored stromal expansion Pallikaris IG. Customized pachymetric
for crosslinking the ultrathin ectatic 3. Kolozsvari L, Nogradi A, Hopp B, Bor guided epithelial debridement for
cornea offers a ray of hope for many Z: UV absorbance of the human cornea corneal collagen cross linking. BMC
in the 240- to 400-nm range. Invest Ophthalmol. 2009;9:10.
Ophthalmol Vis Sci 2002; 43:2165-8. 9. Jacob S.Contact Lens-Assisted CXL
for Thin Corneas.J Refract Surg
4. Pearson AR, Soneji B, Sarvananthan N, 2014:30:366-72.
Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
www. dos-times.org 57
DIAGNOSTICS DISCUSSION
Posterior Keratoconus
Uma Sridhar, Shahana Mazumdar, Jyoti Batra
Case 1 keratoconus being a likely possibility. Peter’s anomaly was
ruled out due to absence of lenticular opacity. Other forms of
Three year old girl was referred by her paediatrician for mesodermal dysgenesis such as Axenfeld-Reiger’s syndrome
bilateral congenital corneal opacities. Variously diagnosed as was ruled out as iris and rest of anterior segment was
interstitial keratitis, HSV keratitis and treated elsewhere. Child unremarkable. Anterior keratoconus was not considered in
was un-cooperative for slit lamp examination. Refraction was the differential diagnosis due to very young age, fairly regular
done. BCVA was 20/60 U with -2.0/-2.50x 160 OU. Evaluation astigmatism, and bilateral symmetry of the clinical features.
under anesthesia was done (Figure 1). Bilateral central corneal
opacity with a ring of pigment around the opacity (resembling Topography could not be done as child was very
Fleishers ring). Central thinning and mild ectasia was seen. uncooperative. Anterior segment Optical coherence tomography
No lenticular opacity was present. Fundus was unremarkable. could be done (Figure 2 and 3). Anterior segment OCT showed
IOP measured by Tonopen was 12 mm Hg OU. Mesodermal uniform curvature and lack of ectasia of the anterior surface
dysgenesis was the initial clinical diagnosis with posterior of the cornea and a localised area of ectasia of the posterior
Figure 1: Right cornea of child during EUA showing central corneal Figure 4: Slit lamp image of right eye of the elderly gentleman. Localised
opacity and scarring with circumscribed pigmentation. area scarring of cornea and thinning with a ring of pigmentation around
the area. Posterior corneal curvature shows ectasia.
23
Figure 2&3: AS OCT of the child. Normal anterior curvature of cornea and localised thinning and ectasia of posterior corneal curvature.
www. dos-times.org 59
DIAGNOSTICS DISCUSSION
curvature of the cornea with a localised
5 thinning in that area. This confirmed the
diagnosis of posterior keratoconus.
Case 2
Sixty year old gentleman who
had bilateral corneal opacities since
childhood. No history of trauma,
exanthematous fever or any other
predisposing factor. UCVA and BCVA
was CF 3 meters OD and 20 /60 in OS.
Slit lamp examination showed corneal
scarring OD> OS, presence of Fleishers
ring, central corneal ectasia along with
localised thinning and ectasia of the
posterior surface of the cornea (Figure
4). Features of circumscribed posterior
keratoconus were seen such as corneal
opacity in the area of thinning and ectasia
of the posterior corneal curvature.
Orbscan II was done (Figure 5 and
6 6). Orbscan features confirmatory of
posterior keratoconus were
1. Steep posterior float (62.2) way
above normal cut off of 55 suggesting
posterior ectasia
2. Similar amount of irregularity
in 3 mm and 5 mm ones unlike
anterior keratoconus where 5.mm
zone irregularity exceeds 3 mm zone
irregularity
3. Steepness more in horizontal
meridian unlike anterior keratoconus
where inferior steepening is seen.
Figure 5&6: Orbscan images of right and left eye of the elderly gentleman. Step posterior float,
equal irregularity in 3 and 5mm zone, horizontal steepening, and circumscribed area of thinning
seen.
Financial Interest: The authors do not have any financial interest in any procedure/product mentioned in this manuscript.
Cornea Department ICARE Eye Hospital, NOIDA, U.P. India.
Dr. Uma Sridhar MS, DNB, FRCS Dr. Shahana Majumdar MS Dr. Jyoti Batra MD, DNB, FICO
60 DOS Times - July-August 2015
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