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Published by DOS Secretariat, 2020-02-18 02:18:50

DOS Times_Sept-Oct 2019_Low Res

DOS Times_Sept-Oct 2019_Low Res

DOS Office Bearers

Dr. Rakesh Mahajan Dr. Subhash C Dadeya Dr. Namrata Sharma Dr. Hardeep Singh
President Vice President Secretary Joint Secretary

Dr. Jatinder S Bhalla Dr. Vinod Kumar Dr. Manav Deep Singh
Treasurer Editor Library Officer

Executive Members

Dr. Dewang Angmo Dr. Jatinder Bali Dr. Shantanu Gupta Dr. C. P. Khandelwal

Dr. Rahul Mayor Dr. Vipul Nayar Dr. Rajendra Prasad Dr. Kirti Singh

DOS Representative to AIOS Ex-Officio Members

Dr. Rohit Saxena Dr. Ashu Agarwal Dr. S.K. Khokhar Dr. Subhash C Dadeya Dr. Arun Baweja


Editorial Retina

07 39 OCT- Angiography in Age Related Macular
What’s New
43 A Case of Congenital Deformity-Optic Disc Pit with
09 Recent Advances in Glaucoma: The First Approvals Associated Maculopathy and Isolated Choroidal
for Rho Kinase Inhibitors Coloboma

13 Rocklatan (Netarsudil and Latanoprost Ophthalmic Neuro-ophthalmology Strabismus
45 The Role of Part Time Occlusion in Treatment of
Subspecialities Amblyopia

Cornea Basics

14 Recent Advances in Corneal Collagen Cross-Linking 48 MN Read Test- Measuring Reading Speed
17 Contact Lens Induced Superficial Punctate 51 Visual Acuity Assessment in Children

Keratopathy PG Corner
19 Sirius Topographer Interpretation made easy
23 Iridocorneal Endothelial Syndrome- A Report on Two 56 Hess and Lee’s Screen

Cases Photoessay

Lens/Cataract 59 Lens Neovascularisation: Neovascularisation on
Intra Ocular Lens with Opacified Vitreous Imitating
28 IOL Power Calculation in Eyes with Posterior Vascularisation on Total Cataract
Segment Pathology
DOS Quiz
31 The Conundrum of Pediatric Cataract
63 Ocular Dimensions and Numbers
36 Effect of Soft Contact Lens on Intraocular Pressure
Measurements Annual Conference

Delhi Ophthalmological Society
3rd-5th April, 2020

at Hotel Ashok, Chanakya Puri, New Delhi

DOS Times - Volume 25, Number 2, September-October 2019 01

Volume 25 No. 2, September-October, 2019

Editor In Chief DOS Times Editorial Board
Namrata Sharma
Editorial Board National Board
Editor Dr. Parul Icchpujani
Prafulla Kumar Maharana Dr. Atul Kumar Dr. Ronnie George
Dr. Aniruddha Maiti Dr. Sushmita Kaushik
Assistant Editors Dr. Apporva Ayachit Dr. Gopal Pillai
Dr. Jitendra Jethani Dr. Usha Singh
Ritu Nagpal Siddhi Goel Dr. Mita Joshi Dr. Subhendu Boral
Dr. P. Dutta Majumdar Dr. Meena Chakrabarti
Dr. Noopur Gupta Dr. Raksha Rao
Dr. Brijesh Kakkar Dr. Kumudini Verma
Dr. Digvijay Singh Dr. Rashmin Gandhi
Dr. Ritika Sachdev Dr. Siddharth Kesarwani
Dr. Dewang Angmo Dr. Chaitra Jayadev
Dr. Rebika Dr. Bibhuti P. Sinha
Dr. Saurabh Sawhney Dr. Amit Porwal
Dr. Reena Sharma Dr. Prashant Bawankule
Dr. Rajat Jain
Deepali Singhal Sahil Agarwal Dr. Jaya Gupta
Ritika Mukhija Rahul Kumar Bafna Dr. Anita Ganger
Dr. Umang Mathur
Farin Shaikh Divya Agarwal Dr. Neera Agarwal
Mohamed Ibrahime Asif Venkatesh Nathiya Dr. Poonam Jain
Dr. Manisha Agarwal
Dr. Hardeep Singh
Dr. Anita Sethi
Dr. Tushar Agarwal
Dr. Rohit Saxena
Dr. Swati Phuljhele
Dr. Vivek Dave
Dr. Mohita Sharma
Dr. Rajesh Sinha
Dr. Aitu Arora
Dr. P.K. Pandey
Dr. H.K. Yaduvanshi
Dr. O.P. Anand

Anusha Sachan Abhijeet Beniwal

Gunjan Saluja Akshaya Balaji
DOS Times - Volume 25, Number 2, September-October 2019 03

04 DOS Times - Volume 25, Number 2, September-October 2019

DOS Execu ve Dear Friends and Colleagues,

Ÿ Dr. Rakesh Mahajan Gree ngs from Delhi Ophthalmological Society!
On Behalf of Delhi Ophthalmological Society, it is our great pleasure to invite you
Ÿ Dr. Subhash C Dadeya to the Interna onal Conference of Delhi Ophthalmological Society (I-DOS) to
Vice President be held from 18th to 21st March, 2020 at Bhutan. This Conference will bring
together prac oners, researchers and educators from India and abroad who are
Ÿ Dr. Namrata Sharma engaged in state of art ophthalmic academic work.
The Delhi Ophthalmological Society, with over 9500 members across India is
Ÿ Dr. Hardeep Singh commi�ed to furthering the cause of con nuing medical educa on and
Joint Secretary promo ng camaraderie and fellowship amongst ophthalmologists worldwide.
The I-DOS conference is a much awaited, me-honored academic fiesta, which
Ÿ Dr. Ja nder S Bhalla a�racts faculty, trade exhibitors and delegates from all over the world.
The conference will be a celebra on of ophthalmology featuring the best works
Ÿ Dr. Vinod Kumar in the fields of Cataract, Refrac ve Surgery, Cornea, Glaucoma, Strabismus,
Editor Neuro-ophthamology and Occuloplasty. The diverse program will feature
invited Faculty talks (Free papers and Eposter).
Ÿ Dr. Manav Deep Singh
Library Officer As you will venture out of the confines of the state of the art conference hall and
the world of ophthalmology, the vibrant Bhutan along with its legendary
Execu ve Members hospitality and bustling energy will enthrall you.

Ÿ Dr. Dewang Angmo We look forward to gree ng you at Interna onal Conference of Delhi
Ÿ Dr. Ja nder Bali Ophthalmological Society, at Bhutan from 18th to 21st March, 2020.
Ÿ Dr. Shantanu Gupta
Ÿ Dr. C. P. Khandelwal Feel free to contact us for any clarifica on
Ÿ Dr. Rahul Mayor
Ÿ Dr. Vipul Nayar With kind Regards,
Ÿ Dr. Rajendra Prasad
Ÿ Dr. Kir Singh


Ÿ Dr. Ashu Agarwal
Ÿ Dr. Rohit Saxena

Ex Officio Members

Ÿ Dr. S.K. Khokhar
Ÿ Dr. Subhash C. Dadeya
Ÿ Dr. Arun Baweja

Dr. Rakesh Mahajan Dr. Namrata Sharma Dr. Ja nder S Bhalla

President, DOS Secretary, DOS Treasurer, DOS

Address For All Correspondence

Prof. (Dr.) Namrata Sharma
Secretary-Delhi Ophthalmological Society
Room No 479, 4th Floor
Dr. Rajendra Prasad Centre for Ophthalmic Sciences
AIIMS, Ansari Nagar, New Delhi-110029, Delhi, INDIA
Email: [email protected]
Web: DOS Times - Volume 25, Number 2, September-October 2019 05

Day - I th March, Day - I th March,

Ÿ Arrive Paro transfer to otel (5 kms, 15 min drive) Ÿ Breakfast at hotel
Ÿ Arrive at Paro, Check in at the hotel Ÿ A er breakfast drive to Thimphu (55 km 1: 0 hrs)
Ÿ Early Lunch at the hotel Ÿ Proceed to Sightseeing Thimphu
Ÿ Evening an exploratory walk around Paro main street Ÿ En route Lunch
Ÿ Later in the day drive back to Thimphu
and market area Ÿ Dinner at the hotel. Overnight at the hotel in Paro.
Ÿ Dinner at the hotel and Overnight at the hotel in Paro.
Day - I st March,
Day - I th March,
Ÿ Early Breakfast
Ÿ Breakfast at hotel Ÿ Post Breakfast check out from the hotel and get transfer
Ÿ alf day conference at the hotel followed by lunch
Ÿ A er lunch, proceed for Sightseeing of Paro. to the airport for your ight back home.
Ÿ Dinner at the hotel.
Ÿ Overnight at the hotel in Paro.

Flight Details

Carrier light Cla Date Day rom o Departure Arri al
3 hutan Air 3 ono y - ar ed Delhi ndia Paro hutan 0530 00
3 hutan Air ono y Paro hutan Delhi ndia 5
2 - ar at 325

Package Includes

Air fare as per ight details men oned as per present tari . The same is subject to change at the me of confirma on of

0 Nights accommoda on at Paro (Bhutan) at otel Le Meridien Paro, Riverfront
Bu et, Lunches, Dinner at the hotel
01 Enroute Lunch at Thimphu

alf Day Conference at hotel
Sightseeing as per the above i nerary
All Transfers by Non AC Coach
Local sight-seeing tour in Paro Thimphu with English Speaking Guide
Bhutan Permit

06 DOS Times - Volume 25, Number 2, September-October 2019


From the
Editor Desk

Prof. (Dr.) Namrata Sharma Respected Seniors and Friends,
Delhi Ophthalmological Society has been an example of the clinical and academic
(MD, DNB, MNAMS) work over the years. Continuing with the tradition of distinctive monthly clinical
meets, DOS monthly clinical meet was conducted on January 12, 2020 at Dr.
Hony. General Secretary Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS which was prodigious
Delhi Ophthalmological Society with case presentations, interactive clinical talks and mini symposiums featuring a
plethora of newer techniques and tips.
Cornea, Cataract & Refractive Surgery Services Celebrating the amalgamation of scientific knowledge, networking, trade and
Dr. R.P. Centre for Ophthalmic Sciences, delegates from all over the world, we look forward to greet you all at the International
All India Institute of Medical Sciences (AIIMS) DOS Conference at picturesque Bhutan from 18th to 21st March, 2020 and annual
New Delhi DOS at Hotel Ashok, New Delhi on 3rd – 5th April, 2020.
To inculcate the practice of equipoise between work and leisure, Delhi Ophthalmic
Society is organising sports day and picnic on 1st March 2020. We look forward to
welcome you all to celebrate a day filled with many fun-frolic activities at Rashtriya
Swabhiman Khel Parisar, Pitampura, New Delhi.
Overwhelmed by the encouraging response to our previous issue, we promise to
fulfil your expectations of enriching the dimensions of ophthalmic knowledge in
this as well as forthcoming issues of DOS Times.
Looking forward to meet you all soon at upcoming DOS meetings.
With best wishes. DOS Times - Volume 25, Number 2, September-October 2019 07

What’s New

Recent Advances in Glaucoma:
The First Approvals for Rho
Kinase Inhibitors

Jatinder Bali & Ojasvini Bali
Hindu Rao Hospital, New Delhi, India

Abstract: Glaucoma, the fourth leading cause of blindness, blinds causes irreversible blindness in 4.0 million people worldwide out of which
about 1.15 million are in India. In India the estimated number of glaucoma patients is 12 million which is one fifth of the global morbidity of
glaucoma. Elevation of intraocular pressure (IOP) is the only proven modifiable risk factor for most forms of glaucoma. Different etiological
mechanisms have been proposed for increased IOP. Aqueous humor (AH) drainage from conventional or trabecular and uveoscleral
pathway is a proven cause in most glaucoma patients and especially so in primary open angle glaucoma. IOP reduction slows vision loss
and remains the mainstay of treatment for all types of glaucoma. Rho kinase is a serine/threonine protein kinase. It is a downstream effector
of Rho GTPase, a Ras superfamily GTPase. It has a role in the conventional path of aqueous drainage. Rho Kinase (ROCK) inhibitors
Ripasudil, K-115 and Netarsudil, AR-13503 have recently been approved for ophthalmological use in therapy of glaucoma as IOP-lowering
agents. This is a brief overview of the Rho Kinase (ROCK) inhibitors.

Glaucoma causes irreversible blindness or latanoprost is being exploited to GAPs are activated by receptors in the
in 4.0 million people worldwide and is harness additive efficacy to lower IOP. cell membrane6,7.
the fourth leading cause of blindness. RhoA has many downstream effectors
Elevation of intraocular pressure (IOP) Rho kinase, a serine/threonine protein like the best studied coiled-coil serine/
is the only proven modifiable risk kinase, is instrumental in the regulating threonine kinase, also called Rho
factor for most forms of glaucoma1. and modulating cell shape and size kinase, which has two isoforms--
Different etiological mechanisms by changes on the cytoskeleton. Rho ROCK1 (ROKb/P160) and ROCK2
have been proposed for increased kinase is a downstream effectors of (ROKa). Rho kinase genes are located on
IOP. Aqueous humor (AH) drainage Rho GTPase. Rho GTPases belong chromosome 2[ROCK2 (ROKa)] and 18
from conventional or trabecular and to Ras superfamily-which contains [for ROCK1 (ROKb/P160)].8,9,10.
uveoscleral pathway is a proven cause in monomeric GTP-binding proteins. N-terminal serine/threonine kinase
most glaucoma patients and especially The roles of RhoA, Rac1 and CDC42 domain is attached to a coiled-coil
so in primary open angle glaucoma. IOP have been elucidated in the regulation region with the Rho-binding domain
reduction slows vision loss and remains of actin dynamics and various actin- (RBD) and a pleckstrin homology
the mainstay of treatment for all types associated cellular activities.4,5 The domain with a C terminus cysteine-rich
of glaucoma. intracellular GTPases act as molecular domain. 9 65 percent homology exists
Rho Kinase (ROCK) inhibitors switches- between ROCK1 (ROKb/P160) and
Ripasudil, K-115 and Netarsudil, AR- ROCK2 (ROKa). While many cellular
13503 have recently been approved 1. an active conformation with GTP- effects are common to both isoforms
for ophthalmological use in therapy binding and some isoform-specific activities have
of glaucoma as IOP-lowering agents in also been described.
Japan and the United States of America. A 2. inactive conformation with GDP- Rho kinase is activated by Rho GTPase
Rho kinase/norepinephrine transporter binding. and then it phosphorylates various
inhibitor will soon complete Phase 3 intracellular substrates characterized
clinical development2,3. Additionally, Guanine-nucleotide-exchange-factors substrates include myosin light chain
combination therapy using Rho kinase (GEFs), GTPase - activating - proteins (MLC), myosin phosphatase substrate
inhibitors in combination with timolol (GAPs) and guanine-nucleotide-
dissociation - inhibitors (GDIs) control
and modulate the transformation of
GDP and GTP binding4. These GEFs and DOS Times - Volume 25, Number 2, September-October 2019 09

What’s New

1 (MYPT1, the regulatory subunit of better in elevated pressures only. patients when used as monotherapy.
myosin phosphatase), LIM kinase, Additive efficacy demonstrates
CP1-17, calponin and the ERM (ezrin, The Rho GTPase/Rho kinase signaling that the Rho kinase mechanism of
radixin and moesin) proteins. Rho pathway is an identified mechanism lowering IOP by increasing trabecular
kinase, acting through substrates, integrating inputs from various external outflow can be used concurrently with
regulates actin cytoskeletal dynamics, signals /factors to generate intracellular other approved classes of glaucoma
actomyosin contraction, cell adhesion, products to regulate cellular changes drugs. The results of phase 3 clinical
cell stiffness, cell morphology and affect AH outflow through the trials of Rho kinase/norepinephrine
ECM reorganization. While cellular trabecular pathway. This work is transporter inhibitor Netarsudil (Aerie
contraction can be regulated via both providing information about other Pharmaceuticals) are awaited. In phase
calcium-dependent and independent related molecular pathways and targets 2 clinical trials in elevated IOP patients
means involving myosin light chain for pharmacological manipulation of 0.02% Netarsudil instilled topically
kinase and myosin phosphatase, IOP. Studies to elucidate Rho/Rho kinase once-daily reduced mean diurnal IOP
respectively, Rho kinase has been signaling and the effect of external cues ranging from 5.7 to 6.8 mmHg.14
demonstrated to regulate cellular in the healthy AH outflow pathway and 0.02% Netarsudil demonstrated same
contraction in smooth muscle tissues dysregulation of this pathway (eg in IOP lowering effect at both lower and
mainly through modulating myosin aging and glaucoma) are still required higher baseline IOPs in contrast to
II activity in a calcium-independent but the work from animal models has the gold standard Latanoprost which
manner. shed a lot of light on the working of shows better efficacy at higher baseline
the pathway. Apart from lowering pressures. A Phase 1 study in healthy
Its action on calcium-independent IOP, Rho kinase inhibitors also provide subjects with low baseline IOPs (14-20
regulation of smooth muscle neuroprotection by reduced retinal mm of Hg) 0.02% Netarsudil in once
contraction is well known. Alan Hall, ganglion cell apoptosis and anti-fibrotic daily dose reduced mean diurnal IOP
in his classical treatise, demonstrated activity to slow or prevent tissue from 16.2 mmHg to 11.3 mmHg after
that Rho kinase pathway regulated the scarring following glaucoma filtration 8 days of treatment15. Thus the drug is
actin cytoskeleton and coordinated surgery. Rho kinase inhibitors inhibited being looked at with interest for the
different cellular responses like shape TGF-2, lysophosphatidic acid (LPA) and ocular hypertensive patients following
and adhesion.5 Cytoskeletal dynamics, RhoA-induced cell transdifferentiation the results of the analysis of follow up
actomyosin contractility, cell adhesion, of the trabecular meshwork cells to of the cohort of OHTS patients and
cell stiffening, cell morphology and myofibroblastic cells12. also for normotensive glaucoma. It has
extracellular matrix reorganization been postulated that substantial IOP
are all mediated by that Rho kinase Several studies to evaluate ocular reductions in lower baseline IOPs could
pathway. Aqueous Humor outflow hypotensive effects of different Rho be due to Netarsudil’s action of lowering
occurs through the trabecular pathway kinase inhibitors in humans have episcleral venous pressure reported in
and the uveoscleral pathway. The been undertaken. Some of the Rho rabbits16. Episcleral venous pressure
trabecular path consists of, trabecular kinase inhibitors evaluated for clinical is reported to account for more than
meshwork, juxtacanalicular tissue, safety and efficacy in humans are half of measured IOP in normotensive
Schlemm’s canal and the aqueous K-115 (ripasudil), fasudil, AR-13324 patients. Hence the action could be
drains into episcleral veins. The (netarsudil), AMA0076,SNJ-1656 and used as an additive effect in most forms
cytoskeletal and extracellular matrix AR-12286. Ocular hypotensive effects of glaucoma.
changes affect the aqueous outflow have been demonstrated in these agents.
through the conventional or trabecular Ripasudil (Kowa) has advanced to phase Aerie Pharmaceuticals has reported that
pathway. Physiological evidence now 3 clinical studies in Japan and netarsudil PG324-a fixed combination of 0.005%
suggests a relationship between Rho (Aerie) to phase3 study in USA. In Japan, Latanoprost and 0.02%Netarsudil
kinase functionality and AH outflow Ripasudil has been approved recently in once-daily instillation gave IOP
in elevated as well as normal intra- for treatment of ocular hypertension reductions 1.6-3.2 mm of Hg greater
ocular pressure. Rho kinase inhibitors and glaucoma13. Additive efficacy in than latanoprost alone. It is currently in
are shown to alter cell shape of the combination with beta blocker timolol phase 3 clinical trial.
cells in the trabecular meshwork. (Aqueous Humour production blocker)
The enhanced transport through the and prostaglandin F2 analog latanoprost Rho kinase inhibitors may also be used
conventional pathway lowers the IOP11. (uveoscleral outflow enhancer) has as neuroprotective agents. Rho kinase
Additional changes in the permeability been reported. In phase 3 trials 0.4% signaling is involved in different central
of the episcleral vessels adds to the effect Ripasudil administered topically twice nervous system (CNS) disorders17. Rho
in normotensive intra-ocular-pressure a day was reported to reduce mean GTPase signaling pathway is involved
compared to the other drugs which act diurnal IOP by 2.9 mmHg in glaucoma in axonal outgrowth inhibition by

10 DOS Times - Volume 25, Number 2, September-October 2019

What’s New

Nogo, myelin-associated glycoprotein The Rho GTPase/Rho kinase signaling 7. Garcia-Mata R, Burridge K. Catching
(MAG) and oligodendrocyte-myelin pathway is increasingly being a GEF by its tail. Trends Cell Biol 2007;
glycoprotein (OMgp)17. Rho GTPase postulated as an important mechanism 17:36-43.
and Rho kinase influence neuronal cell in integrating inputs from external
death by affecting activity of several factors and generating outputs as well 8. Fukata Y, Amano M, Kaibuchi K.
molecules involved in cell survival as cellular effects regulating aqueous Rho-Rho-kinase pathway in smooth
and death like PTEN (Phosphatase and humour outflow through the trabecular muscle contraction and cytoskeletal
Tensin homolog) and microtubule- pathway. Ripasudil is the first Rho reorganization of non-muscle cells.
associated proteins. kinase inhibitor approved for the Trends Pharmacol. Sci. 2001; 22: 32-39.
treatment of patients with glaucoma.
Goldhagen et al demonstrated elevated Rho kinase/norepinephrine transporter 9. Rao PV, Pattabiraman PP, Kopczynski
levels of RhoA and Rho kinase at the inhibitor will soon complete Phase 3 C. Role of the Rho GTPase/Rho kinase
optic nerve head and optic nerve head clinical development. Additionally, signaling pathway in pathogenesis and
thereby elucidating role of Rho GTPase combinatorial therapy using Rho treatment of glaucoma: Bench to bedside
signaling in optic nerve damage due kinase inhibitors in combination research. Exp Eye Res. 2017; 158:23-32.
to glaucoma. The rat optic nerve crush with timolol or latanoprost is being
model of retinal ganglion cell apoptosis exploited to harness additive efficacy 10. Thumkeo D, Keel J, Ishizaki T, Hirose
and axonal degeneration demonstrated to lower IOP. Importantly, as this work M, Nonomura K, Oshima H, Oshima
similar findings. Apoptosis and continues, it is providing important M,Taketo MM, Narumiya S. Targeted
axonal degeneration were associated and novel insights into other related disruption of the mouse rhoassociated
with elevated levels of RhoA, RhoA molecular pathways and targets for kinase 2 gene results in intrauterine
activation, caspase-3 and ROCK2 in the pharmacological manipulation of IOP. growth retardation and fetal death. Mol.
retinal ganglion cell layer18. Most significantly, additional studies Cell Biol. 2003; 23: 5043-5055.
are required to understand how Rho/
Experimental studies have shown Rho kinase signaling is regulated by 11. Epstein DL, Rowlette LL, Roberts BC.
that inhibition of the Rho/Rho external factors in the healthy AH Acto-myosin drug effects and aqueous
kinase signaling pathway resulted outflow pathway, as well as to identify outflow function. Investigative
in suppression of neuronal damage the basis for dysregulation of this Ophthalmol. Vis. Sci. 1999; 40: 74-81.
in different CNS disease models. pathway with aging and ultimately in
It also increased axonal extension glaucomatous eyes. 12. Pattabiraman PP, Rinkoski T, Poeschla E,
and increased neuronal survival. C3 Proia A, Challa P, Rao PV. RhoA GTPase-
exoenzyme induced RhoA inhibition References induced ocular hypertension in a rodent
and shRNA mediated RhoA suppression model is associated with increased
increased axonal outgrowth and retina 1. Flaxman S, Bourne R, Resnikoff S, fibrogenic activity in the trabecular
ganglion cell survival in different animal Ackland P, Braithwaite T, Cicinelli M meshwork. Am. J. Pathol.2015; 185:496-
glaucomatous damage models. Rho et al. Global causes of blindness and 512.
kinase inhibitors like Fasudil (HA1007), distance vision impairment 1990–2020:
Ripasudil (K-115), Y-39983 (SJN-1656) a systematic review and meta-analysis. 13. Inoue T, Tanihara H. Rho-associated
and Y-27632 exhibited neuroprotection, The Lancet Global Health [Internet]. kinase inhibitors: a novel glaucoma
enhanced axonal outgrowth and RGC 2017 [cited 8 September 2019];5:1221- therapy. Prog. Retin Eye Res. 2013; 37:
survival in animal models. Fasudil and 1234. 1-12.
Y-39983 demonstrated increased blood
flow to the optic nerve head in rabbits. 2. Sturdivant JM, Royalty SM, Lin CW, 14. Levy B, Ramirez N, Novack GD,
Rho GTPase and Rho kinase inhibitors Moore LA, Yingling JD, Laethem CL, Kopczynski C. Ocular hypotensive
are therefore potential neuroprotective et al. Discovery of the ROCK inhibitor safety and systemic absorption of AR-
agents19 awaiting a studies to Netarsudil for the treatment of open- 13324 ophthalmic solution in normal
demonstrate neuroprotective effect in angle glaucoma. Bioorg Med Chem Lett. volunteers. Am. J. Ophthalmol. 2015;
human patients. 2016;26:2475-80. 159: 980-985.

Asymptomatic transient conjunctival 3. Garnock-Jones KP. Ripasudil: first global 15. Lewis RA, Levy B, Ramirez N, Usner DW,
hyperemia is the most common adverse approval. Drugs. 2014;74:2211-5. Novack GD. Fixed-dose combination
event reported with use of different of AR-13324 and latanoprost: a double-
Rho kinase inhibitors. Conjunctival 4. Burridge K, Wennerberg K. Rho and Rac masked, 28-day, randomised, controlled
hyperemia expected from Rho kinase take center stage. Cell 2004;116: 167-179. study in patients with open-angle
inhibitors because they relax smooth glaucoma or ocular hypertension. Br. J.
muscle cells and dilate blood vessels. 5. Hall, A. Rho family GTPases. Biochem. Ophthalmol. 2016; 100: 339-344.
Soc. Trans. 2012; 40: 1378-1382.
16. Sturdivant JM, Royalty SM, Lin CW,
6. Cherfils J, Zeghouf M. Regulation of Moore LA, Yingling JD, Laethem
small GTPases by GEFs, GAPs, and GDIs. CL, Sherman B, Heintzelman GR,
Physiol. Rev. 2013; 93: 269-309. Kopczynski CC, deLong MA. Discovery
of the ROCK inhibitor netarsudil for
the treatment of open-angle glaucoma.
Bioorg. Med. Chem. Lett. 2016;26: 2475-

17. Fujita Y, Yamashita T. Axon growth DOS Times - Volume 25, Number 2, September-October 2019 11

What’s New

inhibition by RhoA/ROCK in the central 19. Van de Velde S, De Groef L, Stalmans I, Corresponding Author:
nervous system. Front. Neurosci2014; 8: Moons L, Van Hove I. Towards axonal
338. regeneration and neuroprotection in Dr. Jatinder Bali
glaucoma: rho kinase inhibitors as Hindi Rao Hospital
18. Goldhagen B, Proia AD, Epstein DL, promising therapeutics. Prog. Neurobiol. New Delhi, India
Rao PV. Elevated levels of RhoA in the 2015; 131: 105-119.
optic nerve head of human eyes with
glaucoma. J. Glaucoma 2012; 21: 530-

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If you have missed your copy of DOS Times
Please Contact: Secretary DOS: Dr. Namrata Sharma
Room No. 479, 4th Floor, Dr. Rajendra Prasad Centre for Ophthalmic Sciences,
All India Institute of Medical Sciences, New Delhi - 110029.
Ph.: 91-11-26588510  E-mail: [email protected],  Website:

12 DOS Times - Volume 25, Number 2, September-October 2019

What’s New

Rocklatan (Netarsudil and
Latanoprost Ophthalmic Solution)

1Deepali Singhal MD, 2Prafulla K. Maharana MD
1. Clinical Rsearch fellow in Refractive Surgery, Institute of Vision and Optics, University of Crete, Greece,
2. Dr. R.P. Centre for Ophthalmic Sciences, AIIMS, New Delhi, India.

Rocklatan (netarsudil and latanoprost 0.005% once daily. The treatment • Rocklatan® may cause macular
ophthalmic solution) is a fixed-dose duration was 12 months for MERCURY edema (swelling of the macula)
combination of latanoprost (0.05 mg/ 1 and 3 months for MERCURY 2. In these and should be used with caution in
mL (0.005%), a prostaglandin analog studies, Rocklatan achieved its primary patients with known risk factors for
(PGA), and netarsudil (0.2 mg/mL 90-day efficacy endpoint as well as macular edema.
(0.02%) a first-in-class Rho kinase positive 12-month safety and efficacy
(ROCK) inhibitor that has been recently results, demonstrating statistically • Rocklatan® should be used with
approved by FDA in March 2019 for superior IOP reduction over latanoprost caution in patients with a history
the treatment of elevated intraocular and netarsudil at every measured time of herpetic keratitis and not used in
pressure in patients with open-angle point. More than 60% of patients taking patients with active herpes simplex
glaucoma or ocular hypertension. Rocklatan in the two MERCURY studies keratitis.
achieved an IOP reduction of 30%
Drug or more; nearly twice that achieved • Avoid allowing the tip of the
Rocklatan is supplied as a solution for by patients taking latanoprost alone. bottle to touch the eye to avoid
topical ophthalmic administration Rocklatan also helped more patients get bacterial eye infection, which
(netarsudil and latanoprost ophthalmic to low target pressures. has been reported with the use of
solution) 0.02%/0.005% in a multiple- multiple-dose containers of topical
dose vial manufactured by Aerie Adverse reactions ophthalmic products.
Pharmaceuticals. • Conjunctival hyperemia/ red eye
• Contact lenses should be removed
Mechanism of Action (most common, 59%) prior to using Rocklatan®. Contact
It is specifically designed to target • Instillation site pain lenses can be reinserted 15 minutes
the trabecular meshwork (the eye’s • Corneal verticillata following administration of
principal drainage pathway). The • Eye itching, visual blurring, Rocklatan®.
diseased trabecular meshwork is
considered to be the main cause of excessive tearing, eye discomfort (5- • Pregnant and lactating women: no
elevated IOP in open-angle glaucoma 8%) data available to inform any drug-
and ocular hypertension. • Conjunctival hemorrhage associated risks

Dosage Precautions Reference
One drop once daily for three months. • Rocklatan® contains latanoprost, 1. Rocklatan® (netarsudil and latanoprost
Indication: Open-angle glaucoma or
ocular hypertension. which may cause darkening of ophthalmic solution) 0.02%/0.005% [US
the eye color, darkening of the package insert]. Aerie Pharmaceuticals
Contraindication eyelid and eyelashes, and increased Ireland Ltd. Athlone Business &
None growth and thickness of eyelashes. Technology Park, Garrycastle, Athlone,
Color changes may increase as long Co. Westmeath, Ireland.
Efficac as Rocklatan® is administered,
The FDA conducted two Phase III and eye color changes are likely Corresponding Author:
registration trials, MERCURY 1 and to be permanent. Eyelash changes
MERCURY 2. Studies enrolled 301 are usually reversible upon Dr. Deepali Singhal
and 302 subjects with IOP <36 mmHg discontinuation of treatment. Clinical Rsearch fellow in Refractive Surgery,
and compared IOP lowering effect • Rocklatan® should be used Institute of Vision and Optics, University of
of Rocklatan dosed once daily to with caution and may cause Crete, Greece, India
individually administered netarsudil inflammation inside the eye or
0.02% once daily and latanoprost make existing inflammation worse. DOS Times - Volume 25, Number 2, September-October 2019 13


Recent Advances in Corneal
Collagen Cross-Linking

Amar Bhat MD, Vishal Jhanji MD
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA

The introduction of corneal collagen of the methylcellulose-riboflavin. Accelerated Corneal Collagen Cross-
cross-linking (CXL) has made a The stabilization of intraoperative Linking
dramatic impact on the treatment of corneal thickness may decrease risk
keratoconus and other corneal ectasias. of endothelial injury. A randomized In 1862, Bunsen and Roscoe published
Though CXL has been used to delay or a paper describing a law of reciprocity
halt progression of corneal ectasias, study comparing conventional versus with photochemical reactions, stating
implications of cross-linking reach far thatthemagnitudeofthephotochemical
beyond this alone. As more advances accelerated ultraviolet-A (UVA) response is directly proportional to
in cross-linking are discovered, cross- cross-linking using riboflavin with the total irradiation intensity10. The
linking may begin to play a large role in hydroxypropyl methylcellulose implication of this law in cross-linking
treating conditions from axial myopia (HPMC) demonstrated similar is that using a higher intensity for a
to infectious keratitis. Additionally, improvements in visual acuity and shorter time should produce the same
novel techniques or settings may help max keratometric reading after 2 effect as the standard protocol’s lower
provide more customized cross-linking years of follow-up5. Previous studies intensity and longer time (for example,
for patients and allow cross-linking to using dextran-riboflavin had shown 9 mW/cm2 for 10 minutes versus 3
be used in a larger number of patients that accelerated cross-linking did not mW/cm2 for 30 minutes). Using higher
that may otherwise be excluded using produce the same level of corneal irradiation intensity for shorter times
the gold standard, epithelium off flattening as conventional cross- could drastically shorten operative
Dresden protocol (S-CXL). linking6-7. times for keratoconus, so multiple
studies examined the efficacy of using
Ribo avin variations Finally, delivery of riboflavin accelerated CXL (A-CXL). A study by
In initial cross-linking studies, a in epithelium-on cross-linking Wernli et al. compared irradiation
riboflavin 0.1% solution (10 mg techniques has been improved with intensities (3 mW/cm2 to 90 mW/
riboflavin in 10 ml dextran-T-500 the introduction of iontophoresis. cm2) and their respective illumination
20% solution) was used as a Iontophoresis has been used to increase times (30 minutes to 1 minute).11 The
photosensitizer1. The original 20% riboflavin penetration through the study found that there was a significant
dextran solution was found to thin the epithelium and allows for a faster drop-off in efficacy for cross-linking
cornea intraoperatively2, prompting delivery time of riboflavin.8 Retention protocols that exceeded 45 mW/cm2,
the introduction of hypotonic of corneal epithelium allows for faster demonstrating the Bunsen-Roscoe law
riboflavin solutions to swell the visual recovery, decreased infection risk, of reciprocity was valid to only a certain
cornea3. A recent study examined and less post-operative pain. Though extent in CXL.
the efficacy of methylcellulose- efficacious in halting progression,
riboflavin versus dextran-riboflavin4. iontophoresis-assisted epithelium- A recent meta-analysis compared 6
The study demonstrated improved on CXL (I-CXL) may be inferior to randomized controlled trials comparing
visual and keratometric outcomes S-CXL regarding cross-linking depth, A-CXL and S-CXL and found that both
in the methylcellulose-riboflavin intrastromal riboflavin concentration, methods stopped disease progression.12
group. In vivo confocal microscopy and transmissivity of UVA8-9. The meta-analysis also demonstrated no
demonstrated deeper structural effect significant differences in most outcome
of the methylcellulose-riboflavin Further formulations and delivery measures, though best spectacle-
group as well, which the authors techniques of riboflavin, altering its corrected visual acuity was better using
attributed to faster diffusion and diffusion time and permeability into the S-CXL. One limitation of the A-CXL
different intrastromal concentration the cornea, will be instrumental in group in the meta-analysis was the lack
continuing to advance cross-linking in of standardization of A-CXL technique.
the future.

14 DOS Times - Volume 25, Number 2, September-October 2019


Though the meta-analysis did not have time of 12 minutes. Additionally, the yield20. Mazzotta et al. published one-
many cases and trials to incorporate cross-linking effect of RGX was limited year results comparing pulsed versus
into its analysis, the results do help to the anterior 100 microns of the continuous light in epithelium-off
validate A-CXL as a viable technique. cornea. Despite the lack of posterior A-CXL. The light was pulsed in a
stromal cross-linking, the study noted 1 second on/1 second off manner,
Epithelium-on Corneal Collagen significant increases in corneal stiffness effectively doubling the treatment time
Cross-Linking in RGX-treated eyes. A follow-up study of the A-CXL. The pulsed light A-CXL
Despite the well-documented success examined the corneal biomechanical group was found to have improved
of S-CXL, the epithelial debridement response of RGX versus UVA-CXL16. functional outcomes and deeper stromal
can result in significant pain post- The study found that despite the penetration; both groups demonstrated
operatively. The epithelial healing may shallower and shorter treatment, RGX keratoconus stability. A subsequent
also delay visual rehabilitation and led to more corneal stiffening than pilot study demonstrating the efficacy
patient satisfaction with the procedure. UVA-CXL. Another study compared of enhanced-fluence pulsed-light I-CXL
Transepithelial (or epithelium-on) RGX vs UVA-CXL using noncontact with one-year follow-up was published
corneal collagen cross-linking (TE-CXL) optical coherence elastography and by Mazzota in 2018.21 The study found
was developed to circumvent issues demonstrated significant strengthening improvement of uncorrected distance
from epithelial debridement in S-CXL. of rabbit corneas with UVA-CXL, but not visual acuity, maximal keratometry,
A recent meta-analysis comparing with RGX17. Because the rabbit corneas surface asymmetry, and coma in
TE-CXL versus S-CXL examined 8 in the study had average central corneal patients who received this variation
studies with 1 year follow-up and thicknesses over 700 microns, so RGX of epithelium-on I-CXL. Optical
found that the two techniques had only cross-linked the anterior 1/7th of coherence tomography of the corneas
similar visual, refractive, pachymetric, the stroma. Despite this, RGX could be also demonstrated greater than 80%
and endothelial outcomes13. Mean a viable option for cross-linking in very demarcation line detection at 295.8 +/-
keratometry decreased more in the thin corneas or in cases of infectious 20.2 micron depth at 1 month, which
S-CXL groups. In addition to the relative keratitis. is closer to results seen with S-CXL
paucity of studies available for analysis, compared to previous I-CXL treatments.
another limitation of the study was the Another alternative to UVA cross-
heterogeneity of TE-CXL techniques. linking was recently described by Conclusion
Bradford et al.18 The technique of Corneal collagen cross-linking
Modifications in iontophoresis “nonlinear optic corneal crosslinking” continues to see improvements in
protocols, will be instrumental in (NLO-CXL) involves using near-infrared techniques and technologies. These
improving outcomes of TE-CXL. One femtosecond pulses to excite riboflavin continued advancements should
study by Hayes et al. demonstrated a to generate free radical oxygen and lead to more customization of cross-
significant improvement in stromal subsequently cross-link the cornea. The linking therapy and more consistent
penetration of riboflavin in ex vivo study showed an increase in stiffness results with newer techniques. Though
porcine eyes using Ricrolin+ (a brand of and a statistically significant decrease promising, many of these novel ideas
hypotonic riboflavin 0.1% solution) and in corneal topography by 1.0 +/- 0.8 D will require long- term follow-up to
the St. Thomas’/Cardiff iontophoresis at 1 month. The authors believe that demonstrate a similar efficacy and
protocol B, which may yield promising the primary benefit of this technique safety to the gold standard Dresden
results if replicated in vivo14. lies in the ability to customize a cross- protocol.
linking pattern which could have
Alternatives to UVA Cross-Linking implications in treating thin corneas or References
Although UVA cross-linking has been even refractive surgery. 1. Wollensak, G., Spoerl, E., & Seiler, T.
well established and has repeatedly
demonstrated its efficacy in halting the Pulsed Corneal Collagen Cross- (2003). Riboflavin/ultraviolet-a–induced
disease progression of corneal ectasias, Linking collagen crosslinking for the treatment
the depth of penetration of UVA may A 2015 study by Kling et al. found that of keratoconus. American Journal of
be dangerous for the endothelium of higher oxygen availability increases the Ophthalmology, 135(5), 620–627.
significantly thin corneas. In 2013, overall efficacy of UVA-CXL19. Pulsed 2. Kymionis GD, Kounis GA, Portaliou
Cherfan et al. reported an alternative illumination was theorized to increase DM,Grentzelos MA, Karavitaki
technique to UVA-CXL by using rose oxygen concentration during cross- AE, Coskun-seven E, Jankov MR
bengal plus green light (RGX) in rabbit linking; by pausing regularly during & Pallikaris IG. Intraoperative
eyes15. The study did not demonstrate CXL, oxygen diffusion increases, which Pachymetric Measurements during
any toxicity to stromal keratocytes in allows CXL to have a greater effect Corneal Collagen Cross-Linking with
contrast to UVA-CXL and has a treatment by maximizing the photochemical Riboflavin and Ultraviolet A Irradiation.
Ophthalmology, Volume 116, Issue 12,
2336 – 2339. DOS Times - Volume 25, Number 2, September-October 2019 15


3. Hafezi F, Mrochen M, Iseli HP, Seiler T. of the chemical action of direct and cornea by noncontact optical coherence
Collagen crosslinking with ultraviolet-A diffuse sunlight. Proc R Soc Lond. elastography. Invest Ophthalmol Vis
and hypoosmolar riboflavin solution 1862;12:306–12. Sci. 2016;57:112–120.
in thin corneas. J Cataract Refract Surg.
2009;35(4):621–624. 11. Wernli J., Schumacher S., Spoerl E., 18. Bradford S, Mikula E, Kim SW,
Mrochen M. The efficacy of corneal cross- et al. Nonlinear Optical Corneal
4. Thorsrud, A., Hagem, A. M., Sandvik, G. F., linking shows a sudden decrease with Crosslinking, Mechanical Stiffening,
& Drolsum, L. (2018). Superior outcome very high intensity UV light and short and Corneal Flattening Using Amplified
of corneal collagen cross-linking using treatment time. Invest. Ophthalmol. Vis. Femtosecond Pulses. Transl Vis Sci
riboflavin with methylcellulose than Sci. 2013;54:1176–1180. Technol. 2019;8:35.
riboflavin with dextran as the main
supplement. Acta Ophthalmologica. 12. Kobashi, H., & Tsubota, K. Accelerated 19. Kling S., Richoz O., Hammer A.,
Versus Standard Corneal Cross-Linking Tabibian D., Jacob S., Agarwal A., Hafezi
5. Hagem, A. M., Thorsrud, A., Sandvik, G. for Progressive Keratoconus. Cornea. F. Increased biomechanical efficacy of
F., & Drolsum, L. (2018). Randomized 2019;00:1-9. corneal cross-linking in thin corneas due
Study of Collagen Cross-Linking With to higher oxygen availability. J. Refract.
Conventional Versus Accelerated 13. Wen D, Song B, Li Q, Tu R, Huang Y, Surg. 2015;31:840–846.
UVA Irradiation Using Riboflavin Wang Q, McAlinden C, O’Brart D, Huang
With Hydroxypropyl Methylcellulose. J. Comparison of epithelium-off versus 20. Mazzotta C, Traversi C, Paradiso AL,
Cornea, 1. transepithelial corneal collagen cross- Latronico ME, Rechichi M. Pulsed
linking for keratoconus: a systematic Light Accelerated Crosslinking
6. Chow VW, Chan TC, Yu M, et al. One- review and meta-analysis. Cornea. versus Continuous Light Accelerated
year outcomes of conventional and 2018;37:1018-1024. Crosslinking: One-Year Results. J
accelerated collagen crosslinking Ophthalmol. 2014;2014:604731.
in progressive keratoconus. Sci Rep. 14. Hayes S, Morgan SR, O’Brart DP, et al. A
2015;5:14425. study of stromal riboflavin absorption 21. Mazzotta C, Bagaglia S, Vinciguerra R,
in ex vivo porcine corneas using new Ferrise M, Vinciguerra P. Enhanced-
7. Ng AL, Chan TC, Cheng AC. and existing delivery protocols for Fluence Pulsed-Light Iontophoresis
Conventional versus accelerated corneal cross-linking. Acta Ophthalmol. Corneal Cross-linking: 1-Year
corneal collagen cross-linking in the 2016;94:e109–e117. Morphological and Clinical Results. J
treatment of keratoconus. Clin Exp Refract Surg. 2018; 34: 438-444.
Ophthalmol.2016;44:8–14. 15. Cherfan D, Verter EE, Melki S, et al.
Collagen cross-linking using rose bengal Corresponding Author:
8. Jia HZ, Peng XJ. Efficacy of iontophoresis- and green light to increase corneal
assisted epithelium-on corneal stiffness. Invest Ophthalmol Vis Sci. Dr. Vishal Jhanji
cross-linking for keratoconus. Int J 2013;54:3426–3433. Department of Ophthalmology, University of
Ophthalmol. 2018;11:687–694. Pittsburgh School of Medicine, Pittsburgh,
16. Bekesi N, Kochevar IE, Marcos S. Corneal PA, USA
9. Bikbova G, Bikbov M. Standard biomechanical response following
corneal collagen crosslinking versus collagen cross-linking with rose bengal-
transepithelial iontophoresis-assisted green light and riboflavin-UVA. Invest
corneal crosslinking, 24 months follow- Ophthalmol Vis Sci. 2016;57:992–1001
up: randomized control trial. Acta
Ophthalmol. 2016;94:e600–e606. 17. Singh M, Li J, Han Z, Vantipalli S, Liu
CH, Wu C, et al. Evaluating the effects
10. Bunsen RW, Roscoe HE. Photochemical of riboflavin/UV-A and rose-bengal/
researches – Part V. On the measurement green light cross-linking of the rabbit

16 DOS Times - Volume 25, Number 2, September-October 2019


ontact ens In uce Super cia
Punctate Keratopathy

Sanjana Vatsa MS, FPRS, FCRS, Shana Sood DNB
Dr. Agarwals Eye Hospital, Chennai, India

Here is a case of a 24 year old female Figure 1: Fluorescein staining of the cornea showing diffuse punctate erosions (Right eye and
patient who came to our OPD with left eye respectively).
swelling of eyelids, redness, watering,
pain and photophobia in both eyes. there was complete resolution of all potentially exposed to numerous active
Patient had difficulty opening the eyes. signs and symptoms. Cornea was clear ingredients and preservatives such as
She gave history of using soft contact with no fluorescein staining. Thiomersal/ Benzalkonium chloride
lens for the first time ever the previous etc. contained in contact lens cleaning
day. Uncorrected visual acuity was 6/60 Discussion and soaking solutions which can cause
in both eyes. On Slit lamp examination Superficial punctate keratopathy is a potential toxicity2,3. Solution toxicity
the following findings were noted in common problem encountered with should be considered in the differential
both eyes: contact lens use. It is characterized diagnosis of any patient with bilateral
Eyelid- edema. by fine scattered, punctate corneal diffuse superficial punctate keratitis.
Conjunctiva- Diffuse congestion. epithelial loss which stain positively
Cornea- Diffuse punctuate erosions/ with fluorescein. Symptoms include Management
Superficial punctate keratopathy. pain, redness, lacrimation, photophobia, Underlying cause is to be identified.
Fluorescein stain was +ve. There were foreign body sensation and blurring of Following history has to be taken from
no infiltrates. vision. Slit-lamp examination reveals the patient regarding lens material,
Anterior chamber – occasional cells. diffuse conjunctival congestion, duration of contact lens wear, adherence
Pupils- Round, regular and reactive. multiple punctate speckles on the to instructions and safety regimens,
Iris and Lens were normal. cornea which stain with fluorescein. associated ocular conditions such as dry
It occurs either due to contact lens eyes/ allergies.
Management overuse or mechanical trauma to Patients are strictly instructed to
Patient was instructed to discontinue the cornea due to ill fitting lens or discontinue contact lens use till the
contact lens use. She was started allergic / toxic reaction to contact lens corneal erosions heal completely.
on topical medications as follows: solutions1. Contact lens overuse causes Patching the eye should be avoided
Moxifloxacin eye drops 2 hourly, decreased oxygen supply to the cornea to prevent serious infections. Topical
Preservative free lubricating eye drops and alteration in tear film quality and broad spectrum antibiotic medications
hourly and lubricating gel 2 hourly. quantity which in turn leads to dryness such as moxifloxacin / tobramycin eye
Oral analgesics were also prescribed. and thus punctuate erosions on the drops / ointment QID to be prescribed.
Patient returned to OPD the next cornea. Also, a contact lens patient is Frequent administration of preservative
day with significant improvement
in symptoms and signs. There was
reduction in pain and watering. Slit
lamp examination showed reduction in
conjunctival congestion and punctate
erosions on the cornea. Patient was
asked to continue the same medications
and was reviewed after a week. By then DOS Times - Volume 25, Number 2, September-October 2019 17


free lubricating eye drops to be advised. 2. Fonn D, Peterson R, Woods C. Corneal Corresponding Author:
Patients should be well instructed to staining as a response to contact lens
maintain proper contact lens hygiene. If wear. Eye Contact Lens 2010;36:318-21. Dr. Sanjana Vatsa
toxicity is due to a specific lens material Dr. Agarwals Eye Hospital,
/ lens solution, it has to be changed. 3. Watanabe K1, Hamano H. The Chennai, India
typical pattern of superficial punctate
References keratopathy in wearers of extended
1. Prasannakumary c, Jyothy PT. wear disposable contact lenses. CLAO J.
Complications of contact lens. Kerala J

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PG Corner

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All India Institute of Medical Sciences,
New Delhi - 110029

18 DOS Times - Volume 25, Number 2, September-October 2019


Sirius Topographer Interpretation
made easy

Mallikarjun Heralgi DO,DNB, Kavitha V. DO, DNB, Rajashekar J. DO, DNB, Roopashree B. V. DO, DNB,
Manisha Dwivedi MS
Sankara Eye Hospital, Shimoga, India

Sirius is a relatively new addition in Figure 1: Sirius topographer quad map. Figure 3: Pachymetry map.
the enormous collection of corneal
topographers available commercially. It Figure 2: Patient details with acquisition must look into the patient details and
is a device which combines scheimpflug quality. acquisition quality (Figure 2) which are
imaging with a large cone placido disc. can be used to study cornea and to detect mentioned in the right upper section of
Many of the refractive surgeons as risk factors for corneal ectatic disorders. the quad map. Ensure that the quality of
well as general ophthalmologists are Map interpretation both the Scheimpflug and keratoscopic
using Sirius topographer, but not much Typical quadmap of sirius (Figure 1) acquisitions is good as depicted by a
information is available regarding its contains a Pachymetry map, tangential green tick. We have to take a minimum
interpretation. This article is intended anterior map, anterior and posterior of three accurate acquisitions before
to assist in reading and interpretation of elevation map and it should be read in proceeding for interpretation.
the Sirius topography maps. the same order along with summary
indices which are mentioned on the While interpreting quad map, there
Description of the unit right side. are two important elements: maps
It is named after Sirius - the brightest star Acquisition quality and quantitative indices. Each will be
in the night sky. Sirius Topographer, Before we interpret the map, first we discussed below.
commercially made available by CSO
(Florence, Italy) and Schwind eye tech Pachymetry map
solutions, it combines a 3D rotating This map (Figure 3) on the upper left
Scheimpflug camera with an integrated of the quad map shows, the thickness
Placido disc topographer. The data of the cornea in microns (µm): with
for the anterior surface (curvature reference to the Klyce/Wilson scale,
maps) are determined by merging the which is given on the left of the screen,
Placido image and the Scheimpflug as we can see that thicker areas are
images. However, other data of internal shown in cooler colors and thinner
structures eg; posterior cornea, anterior areas are shown in warmer colours. In
lens, and iris (elevation and pachymetry this map corneal thickness is uniformly
maps) are obtained solely from the distributed from centre to periphery.
Scheimpflug images. Important point to consider here is to
look for any abnormal areas of thinning
It has the following special features: and its location from apex, which we
can identify by moving the cursor over
• 25 scheimpflug images and 1 map or it is given in the quantitative
Placido disc image. indices.

• 22 placido rings.
• 21632 (front surface) and 16000

(rear surface) analysed points.
• 12 mm area.
• Diopteric range 1D-100D.
Below is an overview of how each map DOS Times - Volume 25, Number 2, September-October 2019 19


Figure 4: Tangential anterior map showing
symmetric bow tie pattern.

Figure 5: Anterior elevation map.

Figure 7: Tables showing keratometry data and cylindrical power for front and back surface
in 3,5 and 7 mm zone.

Figure 6: Summary indices showing colors represent steeper zones and the The above mentioned map depicts
pupillary offset,thinnest pachymetry,apex values are expressed in diopters. As elevation data of a normal cornea,
keratometry and other parameters. this map is obtained by placido disc, it shows the flat and steep meridian
typical topographic patterns like round, as compared with best fit reference
Tangential curvature map oval, superior and inferior steepening, surface.
This map on the right upper corner symmetric and asymmetric bowtie can
(Figure 4) shows the tangential be seen. INDICES ON TOPOGRAPHY
curvature of the anterior surface, in DISPLAYS
millimeters or diopters, depending Anterior and Posterior Elevation Summary indices
on configuration. With reference to Maps The multimap should always be
the Klyce/Wilson scale cooler colors These maps are in the lower part of interpreted along with the summary
represent flatter areas, while warmer the quad map (Figure 5). The purpose indices (Figure 6) which include the
of this map is to depict the height pupil size, its offset from x and y axis,
at which corneal elevations and value of apex keratometry and thinnest
depressions deviate from the best fit pachymetry. These indices give us
reference surface (BFS). Shades of red the clues on symmetry of curvature.
show elevations and shades of green or Summary indices also contains HVID
blue show depressions with respect to a (Horizontal Visible Iris Diameter)
reference surface, difference is displayed which Indicates the horizontal limbus
as ∆z, which is point-by-point difference size (in mm), anterior chamber depth
along the z axis , in microns. On moving from epithelium which is measured
the cursor over map values of ∆z, Radius as CCT+ AD(here CCT is pachymetry
of best fit sphere (Rbf), asphericity at apex and AD represents anterior
(Q) of BFS along with position of each chamber depth from endothelium),
point in terms of cartesian coordinates anterior chamber volume, iridocorneal
X (horizontal distance from centre) angle, horizontal anterior chamber
and Y(vertical distance from centre) is diameter and corneal volume.
mentioned on the upper left corner of
the map.

20 DOS Times - Volume 25, Number 2, September-October 2019


Figure 8: Shape indices for 6 and 8 mm zone. Figure 9: Keratoconus screening indices. uses to differentiate between normal
and keratoconus (Figure 9 and Figure
Keratometries (Front and Back) Figure 10: Method of keratoconus screening 10), however there are no cut off values
Anterior and Posterior keratometric in sirius. established yet.
values (Figure 7) for 3,5 and 7 mm
zones are displayed below the summary Figure 11: Keratoconus summary printout Symmetry Indices front and back
indices, these include steep and flat K showing composite comparative maps (Sif and Sib)
values with the magnitude and axis of ,keratoconus screening indices,vector These indices are based on tangential
cylinder. These values are very useful graph,catgory of examined cornea. curvature maps and describe the
for understanding the curvature and measured value is represented by black vertical asymmetry between two zones
also planning for toric IOL. line, if the black line falls in green it is of 1.5 mm radius, along the vertical axis
Shape indices normal, if it falls in yellow zone it is in superior and inferior hemisphere.
These parameters (Figure 8) like flat suspicious and if it falls in red zone it is Positive values indicate that inferior
radius(rf), steep radius(rs) define the abnormal. When the black line falls in hemisphere is steeper than the superior
asphero-toric reference surface which yellow and red zone it is represented by one and vice versa.
best approximates the measured a red triangular caution sign.
corneal surface within the chosen zone It implies that higher the values more Anterior and Posterior
(the zone can be selected manually), irregular will be the surface. As we can keratoconus vertex (KVf and KVb)
we specifically need to look these see in figure no 1.8 all shape parameters These indices are derived from elevation
values in the central 8mm zone where for front and back surface are in red maps, and denotes highest point of
keratoconus usually arises. It also zone, thus cornea being examined is ectasia on the anterior and posterior
includes RMS/A (Root Mean Square highly irregular. corneal surface on the Anterior and
per unit area) which represents the Keratoconus screening indices Posterior Elevation Maps respectively.
deviation of the surface being examined Includes various indices which machine
from the best fit sphere. Values of these Baiocchi Calossi Versaci index
parameters are represented as a bar front (BCVf) and back (BCVb)
with green, yellow and red zones. The Named after 3 inventors, baiocchi,
colossi and vercaci (BCV), these indices
take into account the usually altered
corneal aberrations in ectasia like Coma,
Trefoil and spherical aberrations in the
zone where keratoconus is usually seen.

Keratoconus Summary
Keratoconus summary (Figure 11)
is another useful feature in Sirius, it
utilizes tangential curvature (anterior
and posterior), elevation maps (anterior
and posterior) with respect to an
asphero-toric reference surface and
pachymetry maps of an area of central 8
mm along with keratoconus screening
indices which are mentioned earlier,
This type of representation hides
information on astigmatism, medium
corneal power and only highlights the
ectasic area, and categorises the corneas
into 1. Normal 2. keratoconus suspect
3. Keratoconus compatible 4. abnormal
or treated 5. Myopic post-op. These
classification of corneas are represented
in vector graph (Figure 12), where a
red arrow represents the final total
ectatic value of cornea. If its not seen it
is normal, if it falls in green its normal DOS Times - Volume 25, Number 2, September-October 2019 21


Figure 12: Magnified view of vector graph showing vector position in red zone suggestive of Other Features
keratoconus compatible. Sirius also can be utilised in Anterior
segment imaging optical quality and
with acceptable irregularity, if it falls For example In this keratoconus aberrometry analysis, tearfilm analysis,
in yellow keratoconus suspicious, if summary printout we can see abnormal pupillography, meibomian gland
it falls in red keratoconus compatible. area of inferior steepening associated analysis, intracorneal ring segments
However if the red arrow in the final with significant anterior and posterior planning, glaucoma summary
vector graph reaches upto late green elevation on respective maps, along (iridocorneal angle evaluation), contact
zone it suggests that more keratoconus with higher asymmetry and BCV lens fitting and IOL calculation, which
screening indices have a higher value indices giving final vector position (red are beyond the scope of this article.
and in such scenario machine estimates arrow) in the red zone suggestive of With all of these inbuilt features
it as keratoconus suspect. keratoconus compatible. sirius not only useful in refractive
surgery evaluation and diagnosis of
In Keratoconus compatible cases, the Keratoconus follow up keratoconus but also it can be utilized
software also shows detail analysis as a comprehensive device.
of morphology of ectasic area that we can also compare the Keratoconus References
includes, Apical Keratoscopy front indices of two or three acquisitions 1. Bozkurt B,Yilmaz M,Mesen A,Kamis
and back (AKf and AKb), These are in a chronological order, to help in
the Steepest point of the anterior and the understanding of change in these U,Ekinci Koktekir B,Okudan S.
posterior corneal surface, along with indices over time. Correlation of Corneal Endothelial Cell
KVf, KVb, area and volume of ectatic Density with Corneal Tomographic
area. Parameters in Eyes with Keratoconus
.Turk J Ophthalmol 2017;47:255-260.
2. Cornelius K. Nasser etal., Repeatability
of the Sirius Imaging System and
Agreement With the Pentacam HR
Journal of Refractive Surgery Vol. 28, No.
7, 2012.
3. Phoenix -AN user manual guidelines of

Corresponding Author:

Dr. Mallikarjun Heralgi DO, DNB
Sankara Eye Hospital,
Shimoga, India

22 DOS Times - Volume 25, Number 2, September-October 2019


Iridocorneal Endothelial
Syndrome- A Report on Two Cases

1Anuradha, 2Sagarika Patyal
1. Dept. of Ophthalmology, 167 Military Hospital, Dhangu Road, Pathankot, India.
2. Centre for Sight, New Delhi, India.

The iridocorneal endothelial (ICE) Figure 1: Anterior segment findings of right at a distance of 6m. Intraocular pressure
syndrome is a subset of primary corneal eye with peripheral iridotomy, ectropion (IOP) by Goldmann applanation
endothelial disorders associated with uvea and pedunculated iris nodules. tonometry was 36 mmHg and 14
glaucoma1. The term was initially mmHg in right and left eye respectively
introduced by Yanoff to describe three Figure 2: Optic disc findings of the right eye and remained consistently high in
overlapping conditions, namely, Cogan- with CDR 0.8:1 and deep cup. diurnal variation and subsequent
Reese syndrome (iris nevus), Chandler’s symptoms. Thereafter she underwent examinations. Examination of the right
syndrome and essential iris atrophy2. ICE laser peripheral iridotomy in right eye, eye revealed a lusterless cornea with
syndrome typically affects middle aged but her symptoms persisted. hammered silver appearance of the
Caucasian women, is sporadic in nature, On presentation, visual acuity was endothelium on specular reflection,
and is characterized by abnormalities 6/9 unaided in right eye with no 3600 iridocorneal adhesions with a
of the corneal endothelium, iris and improvement on refraction, and 6/6 in peripherally shallow, quiet anterior
angles of anterior chamber leading to left eye by Snellen’s visual acuity chart chamber. The iris showed multiple
progressive synechial angle closure areas of atrophy, with pedunculated
and secondary glaucoma3. Based on the nodules and ectropion uveae (Figire
predominant structure involved, the 1). The lens had an anterior capsular
disease is classified into one of the three opacity. Fundus examination revealed
variants, with secondary glaucoma advanced glaucomatous cupping with a
being a universal feature of all4. vertical cup disc ratio of 0.8:1 (Figure 2).
We present two patients with ICE Examination of the left eye was within
syndrome of different variants, their normal limits (Figure 3a,3b).
evaluation, management and outcome. Investigations: Gonioscopy of right eye:
3600 synechial angle closure. HVF 24-2
Case 1 SITA standard: advanced glaucomatous
A 43 years old lady presented with mild field defect in right eye (Figure 4). OCT
pain and redness of right eye of one and ONH-RNFL :360o RNFL loss (Figure
a half years duration, blurring of vision 5). ASOCT: 3600 synechial angle
in right eye, which was greater during closure (Figure 6). Specular analysis:
the morning hours and was associated polymorphism, reversal of cell borders
with colored haloes around lights. and presence of characteristic ICE cells
There were no other ocular complaints (Figure 7a,7b). All investigations were
and there was no involvement of normal in left eye.
the left eye. There was no history of Based on the patient profile,
autoimmune or connective tissue symptomatology, clinical signs
disorders nor systemic comorbidities. (pedunculated iris nodules, ectropion
The patient had been managed uveae), and investigative findings,
medically initially for raised intraocular she was diagnosed as iridocorneal
pressure (IOP) only in her right eye and, endothelial syndrome (Cogan-
with which she had partial relief of DOS Times - Volume 25, Number 2, September-October 2019 23


Figure 3a: Anterior segment findings of the
left eye.

Figure 6: ASOCT right eye showing
synechial angle closure.

Figure 4: HVF 24-2 showing advanced field
loss in right eye.

Figure 3b: Posterior segment findings of the
left eye.

Reese). Due to uncontrolled IOP Figure 5: OCT ONH-RNFL showing RNFL Figure 7a: Specular count right eye showing
despite medication, Augmented loss in right eye. polymorphism and reversal of cell borders.
trabeculectomy was done with 0.4mg/
ml Mitomycin C. clinical condition continued to Figure 7b: Characteristic ICE cells on
improve. The bleb became well formed, specular analysis.
On first post operative day, IOP was diffusely raised and mildly vascularised However, over a period of the next few
22 mmHg with a diffusely elevated, (Figure 9). The IOP reduced to 8 mmHg months, the patient’s IOP showed a rise
vascularised bleb superiorly along with and was maintained around this level and is currently stable around 20 mmHg
a flat anterior chamber chamber due despite cessation of eye drop Timolol. by Goldmann applanation tonometry
to air bubble behind the iris (Figure This coincided with the tapering of which was not surprising since
8). The patient was placed in supine steroid eyedrops over a period of six iridocorneal endothelial syndrome is
position and the pupil was dilated weeks and we considered the possibility
with atropine resulting anterior of our patient being a steroid responder.
chamber reformation. Postoperatively The anterior chamber was well
the patient was prescribed antibiotic- formed, though the pupil remained
steroid eyedrops in gradually tapering widely dilated without the use of any
doses for six weeks. cycloplegics post initial atropinization
(?Urrets Zavalia syndrome).
One week post surgery, the patient’s
IOP rose to 28 mmHg with flat bleb but
with formed AC. Releasable sutures
were therefore removed. The patient
was advised ocular massage and started
on Timolol 0.5% eye drops twice daily.

On follow up examination the patient’s

24 DOS Times - Volume 25, Number 2, September-October 2019


Figure 8: Findings on first post operative

Figure 13: ASOCT showing synechial angle
closure in left eye.
Figure 11: HVF 24-2 left eye showing
multiple paracentral scotoma.
Figure 9: Post op 2 months with well formed
AC, diffuse bleb.

Figure 14: Specular analysis showing
polymorphism and reversal of cell borders
left eye.

Figure 10: Anterior segment findings of the Figure 12: OCT ONH-RNFL showing adhesions, and atrophic iris changes
left eye with atrophic iris changes and irido- thinning of superior and inferior RNFL in without any iris nodules (Figuew 10).
corneal adhesions. left eye. Fundus examination revealed a cup-
visual acuity was 6/6 and 6/18 unaided disc ratio of 0.7:1 with thin superior and
known for its progressive inflammatory in right and left eye respectively with inferior neuro-retinal rims.
nature. The patient has been restarted no further improvement. IOP was 16 Investigations: Gonioscopy of the left
on topical IOP lowering drugs. mmHg and 28 mmHg in right and eye: 3600 synechial angle closure. HVF
Case 2 left eye respectively with Goldmann 24-2 SITA standard: multiple paracentral
40 years old female presented with applanation tonometer. Anterior and scotoma in left eye (Figure 11). OCT
history of gradually progressive posterior segment of the right eye were ONH-RNFL: thinning of superior and
diminution of vision in left eye, essentially normal. Anterior segment inferior neuro-retinal rims (Figure
associated with pain, foreign body evaluation of the left eye revealed 12). ASOCT: 3600 synechial angle
sensation, redness and coloured microcystic corneal edema with a closure (Figure 13). Specular analysis
haloes around lights. The right eye hammered silver appearance of the : polymorphism with reversal of cell
was asymptomatic and there was no corneal endothelium, 3600 iridocorneal borders (Figure 14). All investigations
past history or history of systemic of the right eye were essentially within
comorbidities. On evaluation, distant normal limits.
Based on patient profile and symptoms,
clinical features (predominantly DOS Times - Volume 25, Number 2, September-October 2019 25


corneal- microcystic edema, hammered changes, and is associated with temporary, due to progressive angle
silver appearance) and investigative abnormal corneal endothelium and closure4. Cases with uncontrolled IOP
findings, the patient was diagnosed iris nodules6. Chandler’s syndrome is are managed with glaucoma fitering
a case of iridocorneal endothelial used to describe the disease entity with surgery11. Due to progressive nature
syndrome (Chandler’s syndrome). predominantly corneal abnormality, of the disease, the success rate of these
However, due to the presence of atrophic viz, hammered metal appearance of the procedures diminishes with time, due
iris changes, possibility of an overlap endothelium and corneal edema7; while to fibrosis and endothelisation of the
between Chandler’s syndrome and Cogan-Reese syndrome is described by bleb, blockage of drainage implant
essential iris atrophy was speculated. characteristic pedunculated iris nodules by endothelial cells, apart from other
The patient was managed with topical and ectropion uveae, along with causes of surgical failure12. Use of
intra-ocular pressure lowering drugs abnormalities of corneal endothelium antifibrotic agents such as Mitomycin
(Brimonidine 0.2% + Timolol 0.5% and PAS8. Another variant, called the C, and mini-shunts may prolong the
twice daily) and lubricating agents. iris nevus syndrome, described by success of these surgeries. However,
Peripheral iridotomy both eyes with Yanoff and Scheie, is characterised most patients eventually require
Nd-YAG laser. Presently the patient’s by iris heterochromia with ectropion multiple procedures13. In our first
clinical condition is stable, with IOP well uveae, fine iris nodules and PAS9. There patient (Case 1), we used Mitomycin
controlled and no further deterioration is considerable overlap in clinical C in a concentration of 0.4mg/ml for
of corneal endothelium. She is on features between these clinical entities. a period of 4 minutes, in an attempt
regular follow up for progression of to prevent fibrosis and preserve bleb
glaucoma. The patients with ICE syndrome function for a longer period of time.
commonly present with symptoms of Corneal edema can initially be managed
Discussion blurred vision, more prominent during with hypertonic saline eye drops and
The iridocorneal endothelial (ICE) morning due to build up of corneal soft contact lenses. It may also reduce
syndrome comprise a group of disorders edema, associated with irritation and to some extent with reduction in IOP.
where the primary pathology lies in foreign body sensation. Patients may With progressive disease, there may
the corneal endothelium and the iris, also notice a change in colour of the be a requirement of keratoplasty14.
leading to progressive angle closure and iris, with change in size, shape and/or Endothelial keratoplasty15,16. (Deep
secondary glaucoma. The exact etiology number of the pupil in the involved lamellar endothelial keratoplasty-
of the syndrome is not fully elucidated, eye. Sometimes, the condition may be DLEK, Descemet stripping endothelial
although viral infections (Herpes incidentally detected during routine keratoplasty- DSEK) and penetrating
simplex virus, Epstein Barr virus) have ophthalmic evaluation10. keraotplasty17 are therapeutic options,
been implicated. A more accepted depending on the extent of corneal
pathogenic mechanism is metaplastic Delay in diagnosis, however, may lead opacification. Good IOP control and
transformation of corneal endothelial to irreversible vision loss due to severely absence of advanced glaucomatous
cells into epithelium-like cells, which damaged corneal endothelium, or changes are good prognostic factors.
migrate in the form of a membrane over advanced glucomatous optic nerve head Since these procedures do not
the angle of the anterior chamber onto changes. Therefore, considering the completely eliminate host endothelial
the iris. Contraction of this membrane, diagnosis of ICE syndrome, especially cells, the disease continues to progress
pulls the iris towards the angle, causing in middle-aged women presenting with with formation of PAS and development/
formation of iris holes with distortion unilateral blurred vision and raised progression of glaucoma18.
of pupil. This also leads to progressive IOP, and confirming with specular
angle closure resulting in secondary microscopy is vital in early institution There is no recommendation of antiviral
glaucoma. The abnormal endothelium of treatment11. therapy in ICE syndrome unless a viral
gives the cornea a hammered silver etiology has been clearly established19.
appearance on slit-lamp examination5. The treatment of ICE syndrome is as per
The syndrome has been widely divided the the predominant clinical variant. References
into three groups based on clinical Patients with corneal edema and iris 1. Allingham R R et al. Shields textbook
picture. All varieties are nonfamilial changes are treated with symptomatic
in nature and are associated with treatment in the form of lubricating of glaucoma. Sixth edition. Lippincott
unilateral glaucoma. Essential iris agents. Once glaucoma develops, the Williams and Wilkins. 2011.
atrophy is characterised by marked first line of treatment is medical in the 2. Yanoff M. Iridocorneal endothelial
peripheral anterior synechiae (PAS), form of topical aqueous suppressants syndrome: unification of a disease
atrophic iris holes and iris surface (beta blockers, alpha agonists, carbonic spectrum. Surv Ophthalmol 1979; 24:1-
anhydrase inhitors), as the pathology 2.
lies in the aqueous outflow pathway. 3. Sitoula R P. Iridocorneal endothelial
IOP control with medical treatment is syndrome. Journal of Nobel College of

26 DOS Times - Volume 25, Number 2, September-October 2019


Medicine Vol.4(1) 2015: 64-65 ID 763093, 9 pages, 2015. 17. J. N. Buxton and R. S. Lash, “Results
of penetrating keratoplasty in the
4. Krachmer J H, Mannis M J, Holland E 11. Laganowski HC, Kerr-Muir MG, iridocorneal endothelial syndrome,”
J. Cornea fundamentals, diagnosis and Hitchings RA: Glaucoma and the American Journal of Ophthalmology,
management. Third edition. Elsevier iridocorneal endothelial syndrome. vol. 98, no. 3, pp. 297–301, 1984.
2011. Arch Ophthalmol 1992; 110:346-350.
18. G. J. Crawford, R. D. Sulting, H. D.
5. Saleem A A, Ali M, Akhtar F. Iridocorneal 12. Yonker JM, Juzych MS: Iridocorneal Cavanagh, and G. O. Waring III,
endothelial syndrome. Journal of the endothelial syndrome. Glaucoma Today “Penetrating keratoplasty in the
College of Physicians and Surgeons 2007; 31. management of iridocorneal endothelial
Pakistan 2014, Vol. 24: S112-S114. syndrome,” Cornea, vol. 8, no. 1, pp. 34–
13. E. A. Doe, D. L. Budenz, S. J. Gedde, and N. 40, 1989.
6. Campbell DG, Shields MB, Smith TR: R. Imami, “Long-term surgical outcomes
The corneal endothelium and the of patients with glaucoma secondary to 19. Alvarado JA, et al: Detection of herpes
spectrum of essential iris atrophy. Am J the iridocorneal endothelial syndrome,” simplex viral DNA in the iridocorneal
Ophthalmol 1978; 86:317-324. Ophthalmology, vol. 108, no. 10, pp. endothelial syndrome. Arch Ophthalmol
1789–1795, 2001. 1994; 112:1601-1609.
7. Chandler PA: Atrophy of the stroma of
the iris, endothelial dystrophy, corneal 14. M. B. Shields, J. S. McCracken, G. Corresponding Author:
edema, and glaucoma. Trans Am K. Klintworth, and D. G. Campbell,
Ophthalmol Soc 1955; 53:75-93. “Corneal edema in essential iris Dr. Anuradha
atrophy,” Ophthalmology, vol. 86, no. 8, Dept. of Ophthalmology, 167 Military Hospital,
8. Cogan DG, Reese AB: A syndrome of pp. 1533–1548, 1979. Dhangu Road, Pathankot, India
the iris nodules, ectopic Descemet’s
membrane, and unilateral glaucoma. 15. M. A. Terry and P. J. Ousley, “Deep
Doc Ophthalmol 1969; 26:425-433. lamellar endothelial keratoplasty: visual
acuity, astigmatism, and endothelial
9. Scheie HG, Yanoff M: Iris nevus (Cogan- survival in a large prospective series,”
Reese) syndrome. Arch Ophthalmol Ophthalmology, vol. 112, no. 9, pp.
1975; 93:963-970. 1541–1548, 2005.

10. Marta Sacchetti, Flavio Mantelli, 16. M. O. Price and F. W. Price Jr., “Descemet
Marco Marenco, Ilaria Macchi, Oriella stripping with endothelial keratoplasty
Ambrosio, and Paolo Rama, “Diagnosis for treatment of iridocorneal endothelial
and Management of Iridocorneal syndrome,” Cornea, vol. 26, no. 4, pp.
Endothelial Syndrome,” BioMed 493–497, 2007.
Research International, vol. 2015, Article DOS Times - Volume 25, Number 2, September-October 2019 27


IOL Power Calculation in Eyes with
Posterior Segment Pathology

1Prashob Mohan, 2Arup Chakrabarti
1. Giridhar Eye Institute, Kochi, Kerala, India
2. Chakrabarti Eye Care Centre, Kochulloor, Trivandrum , Kerala, India

Keywords : IOL power, Vitrectomy IOL, scleral buckling, silicone oil.

With the availability of better optical biometry tended to under estimate matters further as it moves around. If axial
instrumentation, the visual outcomes of axial length3. length is measured in the supine position,
vitreo-retinal surgery are better than ever. In eyes where gas tamponade (C3F8/SF6) is ultrasound will have to cross liquid vitreous
The indications for pars plana vitrectomy used, there is a myopic shift in refraction. followed by silicone oil before reaching the
have expanded and so have the number This may be partly due to anterior shift of retina. So if the silicone oil fill is partial, it
of vitreo-retinal surgeries. Combined the intraocular lens and partly due to change is advisable to perform ultrasound biometry
cataract and vitreo-retinal surgery havealso in the refractive index of the intraocular in the sitting position.
become common place. One of the most medium as vitreous gets replaced by Silicone oil is available in viscosities
common complications of vitrectomy is aqueous. So, a target post operative refraction ranging from 1000 cSt to 5000 cSt..In 1000
the development of cataract. One of the of +0.5 has been suggested to minimise post- cStsilicone oil, ultrasound has a velocity of
challenges encountered while considering operative refractive surprise4. 980 m/s, whereas in 5000 cSt silicone oil, it is
cataract surgery in eyes with coexisting In eyes that undergo scleral buckling, there 1040 m/s. In vitreous, ultrasound travels at a
posterior segment pathology is accurate is elongation of axial length that stabilises speed of 1532 m/s8.
biometry. In this article the nuances of an about 3 months after surgery. More axial This difference causes an erroneous
accurate IOL power calculation in eyes with length elongation has been associated measurement of vitreous cavity depth
common vitreoretinal pathologies will be with more extensive scleral buckling and (VCD). The formula to correct AL in any
discussed. use of adjunctive cryotherapy. So, if scleral silicone oil filled eye is:
buckling is planned, cataract surgery can be
Retinal detachment planned ideally after 3 months of surgery5. 1. VCD 1532 = AL - (ACD+LENS)
Third generation 2 variable formulae like
Without silicone oil tamponade Holladay 1, Hoffer Q or SRK-T don’t require 2. VCDcorrected= VCD1532 x (1/1532)
In general, for a more predictable refractive anterior chamber depth as a variable. They x 980 m/s (or 1040 m/s depending
outcome, it is recommended that vitrectomy calculate anterior chamber depth from on viscosity of silicone oil used.)
be performed first if possible, and then IOL axial length. When these formulae are used
power calculation be performed followed by to calculate IOL power in eyes after scleral 3. AL corrected = VCD corrected +
cataract surgery. buckling, they predict too deep an anterior ACD + LENS
The biometry for eyes with rhegmatogenous chamber depth and hence a stronger IOL
retinal detachment where silicone oil power than needed leading to a myopic Where AL is the axial length, ACD is anterior
tamponade is not used is essentially the error. chamber depth and LENS is lens thickness9.
same as that for normal eyes with the With silicone oil tamponade (1532 is the average velocity of sound in
following considerations. Accurate axial length (AL) measurement aqueous and vitreous)
Optical biometry is more accurate than using ultrasound biometry in silicone oil For silicone oils with viscosity of 1300 cSt,
ultrasound biometry especially in cases of filled eyes can be challenging. The velocity a correction factor of 0.71 multiplied by
macula off retinal detachments1. Optical of sound in silicone oil is lower than that the measured AL corrects for the apparent
biometers measure axial length up tothe in vitreous. This will cause an error in increase in axial length induced by silicone
retinal pigment epithelium, whereas measurement6. oil10.
ultrasound biometers measure up to the Optical biometry is preferred over
internal limiting membrane. So axial length Due to sound attenuation within silicone ultrasound biometry if the media permits. It
measurement by ultrasound biometry can oil, the retinal echo-spike appears smaller is much simpler and involves only changing
lead to falsely short axial length and a myopic and is more difficult to identify7. Hence the axial length settings to silicone oil filled
refractive surprise after retinal attachment2. the sensitivity of the system needs to be eye.
Optical biometers, theoretically should offer increased. Errors in calculation of IOL power may be
an accurate axial length measurement in An incomplete silicone oil fill complicates induced by unsuitable formulae, artefacts
such eyes. However, in practice, in macula or large eyes with axial lengths beyond
off rhegmatogenous retinal detachments, the machine range. Axial length may be

28 DOS Times - Volume 25, Number 2, September-October 2019


impossible to obtain in certain eyes. In such (1.336) If optical biometry is not possible, an image
eyes, any of the following approaches may of the posterior fundus is first obtained using
be considered: AL: Axial length in millimeters a horizontal axial B-scan. The A-scan vector
1. Axial length may be measured prior is then adjusted so as to pass through the
ACD: Anterior chamber depth in middle of the cornea as well as the anterior
tovitreo-retinal surgery and silicone millimetres13 and posterior lens echoes. This ensures that
oil injection the axial length is measured along the visual
Macular diseases axis especially in cases where the fovea lies
2. Silicone oil removal may be on the slope of the staphyloma.
done followed by axial length While using ultrasound biometry for
measurement and cataract surgery. IOL power calculation in patients with Alternatively, a direct ophthalmoscope with
coexisting retinal diseases with macular a cross hair reticule may be used to measure
3. Axial length of fellow eye may be thickening (epi-retinal membrane, diabetic the distance from the centre of the macula to
used. macular edema), there can be a post- the optic nerve head. With the B scan image
operative myopic surprise, after macular showing the optic nerve head void, a vector
4. In case of a partial silicone oil fill, thickness normalises. This is due to under A -scan is simultaneously directed to the
the axial length may be obtained estimation of the cornea- photoreceptor centre of the macula temporal to the optic
from a CT-scan image. layer distance in thickened maculae2. nerve edge displaced by the same distance as
A more accurate estimation of IOL power measured with the direct ophthalmoscope18.
5. The least desirable option would by ultrasound can be made if the increase
be to consider the use of standard in macular thickness obtained by optical References
power IOL11. coherence tomography (OCT) is added to the
ultrasound biometry obtained axial length2. 1. Rahman R, Bong CX, Stephenson
In a siliconeoilfilled eye, a hyperopic shift in Axial length calculation is simpler in optical J. Accuracy of intraocular lens
refraction is expected as the refractive index biometry as optical biometers measure axial power estimation in eyes having
of silicone oil is higher than vitreous12. The length up to the retinal pigment epithelium. phacovitrectomy for rhegmatogenous
postoperative refractive error increases as In patients with coexisting macular holes retinal detachment. Retina
the power incorporated in the posterior and cataract, regardless of the whether (Philadelphia, Pa). 2014;34:1415–20.
surface of the IOL increases. If it is planned vitrectomy with gas tamponade is performed
to maintain silicone oil tamponade for an before, during or after cataract surgery, a 2. Kovács I, Ferencz M, Nemes J, Somfai
extended period, or if there is no plan to myopic shift in post-operative refraction G, Salacz G, Récsán Z. Intraocular
remove silicone oil from the vitreous cavity, is observed14. This may be attributed to lens power calculation for combined
3-8 D should be added to the IOL power an anterior shift of the IOL4. While using cataract surgery, vitrectomy and peeling
that is calculated to achieve emmetropia. If ultrasound biometry in patients with of epiretinal membranes for macular
silicone oil removal is performed at a later coexisting macular holes, a more accurate oedema. Acta Ophthalmol Scand.
date, the patient should be informed that result may be obtained by adding the 2007;85:88–91.
there will be a myopic shift. The amount difference of OCT calculated macular
of refractive shift also depends on the type thickness between affected and normal eyes 3. Pongsachareonnont P, Tangjanyatam S.
of IOL used. It is greatest for a biconvex to the ultrasound measured axial length15. Accuracy of axial length measurements
lens, lesser for a planoconvex lens with the A source of error while performing optical obtained by optical biometry and
plane surface facing posteriorly and least for biometry in patients with macular holes acoustic biometry in rhegmatogenous
meniscus lenses. A rule of thumb that can be may be parafoveal fixation16. Foveal retinal detachment: a prospective study.
followed in this regard is to add 3 D to the fixation may be ascertained if swept source Clin Ophthalmol. 2018;12:973–80.
IOL power in case of a convexo-plane IOL, 6 OCT based devices are used as they make
D in case of a biconvex lens. available an OCT image of the foveal pit. 4. Shiraki N, Wakabayashi T, Sakaguchi
In some patients the silicone oil tamponade A few case reports have suggested that IOL H, Nishida K. Optical Biometry-
has to be executed for long periods of time. power may be overestimated in patients with Based Intraocular Lens Calculation
In these cases IOL power adjustments have sub-foveal choroidal neovascularisation and Refractive Outcomes after
to be considered as silicone oil alters the due to elevation of the retinal pigment Phacovitrectomy for Rhegmatogenous
refractive power of the posterior surface of epithelium and/or malalignment of the Retinal Detachment and Epiretinal
the IOL. visual axis due to parafoveal fixation17. Membrane. Sci Rep [Internet]. 2018 Jul
The additional IOL power to be added to the 27 [cited 2019 Dec 1];8. Available from:
calculated IOL power, to arrive at the power High axial myopia
of IOL to be implanted in a silicone oil filled articles/PMC6063856/
eye can be obtained from the following Ultrasound biometry in patients with high
formula- axial myopia with posterior staphyloma 5. Wong CW, Ang M, Tsai A, Phua V, Lee
Additional IOL power = {(Ns-Nv)/ (AL-ACD)} is prone to error as the axial length may SY. A Prospective Study of Biometric
x1000 be measured to the pit of the posterior Stability After Scleral Buckling Surgery.
staphyloma which is an extrafoveal Am J Ophthalmol. 2016;165:47–53.
Ns- Refractive index of silicone oil location. Optical biometers are preferred in
(1.4034) patients with posterior staphyloma because 6. Sawada A, Nagatomo T, Kitamura K,
the axial length can be measured along the Nao-I N. Axial Length Measurement
Nv- Refractive index of vitreous visual axis. in Silicone-Oil-Treated Eyes. In:
Tane S, Thijssen JM, Fledelius
HC, editors. Ultrasonography in
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14th SIDUO Congress, Tokyo, Japan 12. Smith RC, Smith GT, Wong D. Refractive 17. Shentu X-C, Cheng Y-L, Chen Z-Q, Su
1992 [Internet]. Dordrecht: Springer changes in silicone filled eyes. Eye. Z-A, Zhang L. Differences in intraocular
Netherlands; 1995 [cited 2019 Dec 1]. 1990;4:230–4. lens power calculation in patients with
p. 63–8. (DocumentaOphthalmologica sub-foveal choroidal neovascularization.
Proceedings Series). 13. Shammas HJ. Intraocular lens power Int J Ophthalmol. 2019;12:172–4.
calculations: ultrasound measurement
7. Schröder A, Raphael E. Attenuation of of the challenging eye. Thorofare, NJ: 18. Byrne SF, Green RL. Ultrasound of
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30 DOS Times - Volume 25, Number 2, September-October 2019


The Conundrum of Pediatric

Parikshit Gogate
Dr. Gogate’s Eye Clinic, Pune, Maharashtra, India

Indian ophthalmology is blessed weeks of age) has great anesthesia risk. to transfer the child to the operating
with great cataract surgeons thanks Surgery in the first 6 weekswas found to room. Having a parent around while
to the focus on cataract surgery in be associated with increased incidence inducing anesthesia makes the child
residency and the sheer number of of secondary glaucoma3. There is a more comfortable, and the process
cataract surgeries done1. This leads to refractive shift post-surgery. This is smoother and easier. A favorite toy or
many ophthalmologists to think that greater in infancy, which has led to blanket, along with the parents, should
pediatric cataracts are just soft adult many ophthalmologists questioning be kept near the child when she comes
cataracts, easier to perform. Nothing the wisdom of implanting an intra- out of anesthesia.
could be farther from truth. ocular lens implant in infant cataracts
(congenital and developmental)4. While doing an A-scan we must
Children’s eyes are not just small adult consider the factors affecting axial
eyes. They are different. The sclera Pre-operative work up growth after cataract surgery.
has less rigidity, the anterior capsule There is often a considerable delay
is thicker and more elastic, corneal between a child being detected for Factors affecting axial growth after
curvature and axial length keep on cataract and actually undergoing cataract surgery:
changing and the eye is more prone to cataract surgery5,6. This may vary
inflammation2. As the equator of the from anywhere between 6 months to 1. Normal physiological growth
crystalline lens keeps on producing new half a decade. Fear of surgery, fear of 2. Age at time of surgery
cells, incidence of secondary cataract anesthesia, reluctance on part of health 3. Amount of visual deprivation
and posterior capsular opacification is care givers, cost and distance to the 4. Aphakia or psuedophakia
nearly 100%. tertiary center are some of the barriers7. 5. Laterality: Unilateral cataract eyes
Basic investigations like hemogram,
The growth and development in a urine routine and TORCH titre shorter initially, grow more later
newborn’s eye (wherever available) should be done. 6. Genetics
Cardiac fitness especially in children Of this, age is the most important
• Axial length in newborn: 16.6 to 17 with Congenital Rubella Syndrome and variable. Children below 2 years of age
mm those with Marfan’s Syndrome is a must. at time of surgery with or without IOL
History of seizures and anti-epileptic implantation have greater myopic shift
• Mean keratometric power: 51.2 medication is a must. A pediatrician and variance then older children.
Diopters fitness and pre-anesthesia visit by the
anesthesia team is of great help. A child Measurements of axial length in
• Refractive changes primarily seen usually needs 4 hours of nil by mouth. uniocularpseudophakic/aphakic eye
due to increase in axial length If the surgery is scheduled at 9 am, the and un-operated fellow eye showed
mother should be told to have an alarm no difference in change in axial length
• Maximum axial growth by 2 years at 4:30 am and breast feed the infant. between 2 eyes.
• Lens and total eye power decreases The surgery should be scheduled early
in the morning, to have a shorter fasting The expected myopic shift after cataract
by 10 diopters in 1st year duration and also allow the anesthesia surgery is summarized in the table
• Further decrease by 3-4 diopters and pediatric team a longer time during below8-10:
the day to manage the child post-
from 2- 10 years age. operatively. Its best to have the child There is a conundrum, should we choose
There is still debate about when and sleep to as late as possible till it’s time for Emmetropia NOW Vs Emmetropia
how to operate cataracts in infants. in ADULT (at 6-8 years of age)
Earlier,even a one day old child would be
operated. Now the thinking is to operate
a child after 6 weeksof age. Surgery
during the perinatal period (upto 4 DOS Times - Volume 25, Number 2, September-October 2019 31


Residual refractive error: Choosing under-correction of 20% of the A-scan A- scan biometry: Applanation
adult IOL power in children <2 years. reading in children< 2years and under- technique indents the globe resulting in
correction of 10% in children 2- 8 under estimation (1D error). Immersion
With expected growth and myopic years12. technique is preferred. Keeping the
shift, the childis expected to have good probe perpendicular is important but
unaided vision in adulthood as she Prost suggested13: there is no way of ensuring that the
becomes emmetropic by then. But this child is fixing on the centre of the probe
means a significant hypermetropia Under-correction of 20% between 1 and since the child is under anesthesia15.
now. Near vision is severely affected 2 years
due to lack of accommodation and it For keratometry, hand held auto
may cause dense amblyopia in case of Under-correction of 15% between 2- 4 keratometer is used in operating room
anisometropia. years as soon as the child is induced, without
using a speculum.BSS can be instilled to
Choosing emmetropia post operatively Under-correction of 10% between 4-8 maintain smooth corneal surface to get
in <2years age years accurate keratometry. Optical biometry
(IOL Master), Partial coherence
This makes for easier amblyopia Infant aphakiatreatment study14: Interferometry (PCI) and I- Trace are
management in early post-operative being used in older and co-operative
period, especially for child with poor 1. 4-6 weeks age: +8 diopters children.
compliance and follow ups.With 2. 6 weeks to 6 months: +6 diopters
myopic shift and ocular growth, use of There is no study that demonstrates a But all power calculation formulae are
contact lens and refractive surgery or visual advantage of one approach over derived from studies on adult eyes.Eye
piggyback IOLmay be resorted to later other. of the child changes considerably post
to correct the residual error. operatively with significant refractive
A-scan Biometry in children has unique change,further compounding the
Enyedi et al. had suggested rule of 7 problems like: issue. A comparative study conducted
(Age in years + residual diopters=7)to by Vasvada et. al (117 eyes) in children
get near emmetropia in teens11: 1. Axial length and keratometry are younger than 2 years age, demonstrated
difficult to measure. that SRK/T and Holladay 2 gave the
1. 1 year old: +6 diopters least prediction error.16 Another
2. 2 year: +5 diopters 2. Need for general anesthesia for series of 461 eyes by Lee BJ et al from
3. 3 year: +4 diopters evaluation and anesthesia related Korea showed that SRK II formula was
4. 4 year: +3 diopters complications. better suited for pediatric IOL power
5. 5 year: +2 diopters calculation17. This was seconded by
6. 6 years: +1 diopters 3. Less reproducible. a series of 128 eyes from Hyderabad
7. 7 years: plano 4. Less predictable with lower where SRK II was found to be better for
8. 8 years and above: -1 to -2 diopters IOL power calculation in children18.
Dahan and Drusedau suggested accuracy compared to adults.
5. Lack of fixation and centration. Intra-operative considerations
6. Absence of an IOL calculation In pediatric cataract surgery, we worry
about the sphere, not the cylinder. As
formula specifically for pediatric the child’s refractive status is going to
eyes. change, multifocals do not offer any
advantage. There would be further
loss of contrast sensitivity. Torics are
rarely indicated. But children tolerate
progressive spectacles very well. As the
child would need sspectacles, its best
to counsel parents about this before
surgery. We have to understand that
surgery is just one important step in a
series of steps needed to improve the
child’s vision.

As there is nearly 100% posterior
capsular opacification (PCO) in children,

32 DOS Times - Volume 25, Number 2, September-October 2019


primary posterior capsulotomy (PPC) the IOL is in the bag as that considerably stereoacuity<480 sec of arc by TNO
is indicated till 6-8years of ageand in reduces the chances of inflammation.A test. One had 60 sec of arc stereopsis,
all mentally challenged/ syndromic peripheral iridectomy may be done in 17 (13.2%) had 240 arc, 30 (23.9%) had
children, after which the child becomes cases with PPC + AV.While choosing the binocular stereoacuity of 480 sec of arc
old enough to sit at a Nd:YAG LASER implant power, there is a conundrum, stereopsis.
for a capsulotomy. Only PPC does not whether to go for ‘emmetropia now’,
help as the thick vitreous base allows i.e. put in the power that has come on For unilateral congenital or
new lens cells to migrate over itas a A-scan, easy for amblyopia treatment developmental cataracts, 11 (21.6%)
scaffoldand obscure the visual axis. now, but would need spectacles later; or had binocular single vision <480
So PPC is to be coupled with anterior ‘emmetropia in teens’, i.e. put in lower seconds of arc on TNO test (one was 60
vitrectomy (AV) till age of at least 6 power than that has come on A-scan, sec, one 120, 4 were 240 and another five
years. So having an automated vitrector difficult amblyopia treatment now, but were 480)26.
is a must! The PPC +AV can be done no spectacles needed later in adulthood.
before or after PCIOL implantation. After the first 8 weeks, the child should For a child, it’s not just distance, but
But after may be safer as at times an be followed up every 3 months till she is near vision that is equally important.
unfolding IOL may extend the posterior 2 years of age. A six-monthly follow-up The child needs good near vision for
capsulotomy. So ideally the surgery in the first decade and an annual one in tasks of daily living like eating and
should be done using a phacomachine, the second decade of life is very helpful. playing and for his /her educational
though SICS is an alternative. In the A secondary Nd:YAG LASER should purposes. Spectacles for near would be
first decade of life, suturing of main port be performed earlier as the capsule is needed for the child as the facility for
and side-ports should be done, a suture easier to break when it thinner rather accommodation is lost during surgery27.
for each millimeter of opening. Single than waiting for it to become fibrosed.
suture for side port and a crossed one for Visual acuity after pediatric cataract
the 2.8 mm incision. Post-operative care, amblyopia surgery is better when -
Surgery is just one crucial step in a series • Pre-operative vision is better.
of steps needed to restore the child’s
Presently sevofluraneinhalation vision. Post-operative care is extremely • Developmental rather than
important21-23. A regular follow-up for congenital cataract.
anesthesia is popularly used. It may be the first six months with visual acuity
assessment, refraction and amblyopia
used with endotracheal intubation or treatment ensure good outcome. A six- • Use of phacoemulsification,
with a laryngeal mask. In slightly older monthly follow-up is needed in the first automated vitrectors.
children and remote places, ketamine decade and an annual follow-up in the
second decade of life. Posterior capsular • Older children.
and peribulbar block are also an opacification (PCO), amblyopia and
secondary glaucoma are the factors
alternative. In the second decade of life, affecting good outcome24,25. Regular • No post-operative uveitis.
many children co-operate for surgery intra-ocular pressure measurement is
under local (and vocal) anesthesia, needed. • Regular follow-up.

peribulbar, sub-tenon or topical In a study looking at the long-term • Binocular Cataracts.
follow-up after cataract surgery,
depending on patient and operating congenital cataracts had the least PCO Recent studies have vouched for
surgeon’s comfort. while developmental the most, as
PPC+AV was restricted to <6 years of the safety and efficacy of anterior
age. vitrectomy28. Precision pulse
There is a debate as to how early vitrectomy has been used for pediatric
to implant an intra-ocular lens? Older children and longer follow-up cataract surgery29.Optic Capture of the
Generally, 8-12 months is an accepted were associated with more PCO. IOL and bag-in the lens are novel ways
norm though some institutes implant of reducing PCO Incidence30-31.
even at 6 months for unilateral Post-operatively, it’s not just vision but
cataracts19,20. For bilateral congenital stereopsis that is also important24,26. In Traumatic cataract
or developmental cataracts, 24-30 the Miraj Pediatric Cataract Study, for Trauma in children can cause cataract.
months of age is a good time as children bilateral congenital and developmental There is usually less delay in children
tolerate aphakic correction well. Since cataracts, 48 (37.2%) had binocular getting operated for traumatic cataract
phacoemulsification has become than congenital or developmental
common, the trend is to implant cataracts32. If there is no co-existing
foldable acrylic IOLs instead of the damage to the cornea and retina,
very safe PMMA lenses. Hydrophobic the visual outcomes of traumatic
acrylic IOLs have an advantage of being cataracts are better than congenital
less prone to pigment dispersion and or developmental cataracts32,33. This
posterior capsular opacification. The may be because the visual system has
most important thing is to ensure that developed in a child who had trauma DOS Times - Volume 25, Number 2, September-October 2019 33


and the cataract surgery restores using Holladays formulae. The surgeon Wilson ME, Lambert SR, Infant Aphakia
the child’s vision. There is a male should know the axial length to use the Treatment Study Group. Complications
preponderance in traumatic cataracts nomogram. in 1st five years following cataract
as boys are more likely to engage in surgery in infants with and without
outdoor activities than girls and are Acknowledgement: Dr. Nikhil intraocular implant in the infant
perhaps less careful! The challenges Rishikeshi, Head of Pediatric aphakia treatment study group. Am J
of anesthesia, IOL power calculation, Ophthalmology Department, H.V.Desai Ophthalmol 2014; 158 (5) : 892-898.
intra-operative PPC+AV and regular Eye Hospital, Pune , Dr. Supriya Phadke
post-operative management are similar of Community Eye Care Foundation, 9. Crouch ER, Crouch ER Jr. pressman
to other cataracts in children. To this Pune and Dr. Prasad Walimbe, pediatric SH. Prospective analysis of pediatric
may be added problems like managing ophthalmologist, Pune for their pseudophakia : myopic shift and post
with a corneal tear, iridodialysis and valuable inputs. operative outcomes. J AAPOS 2002
retinal detachment. Oct;6(5):277-82.
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Pediatric cataract is the commonest measurement techniques in pediatric
cause of treatable blindness in Ramamurthy D, Bhattacharya D, Golnik eyes with cataract Saudi J Ophthalmol
children34,35. After refraction and K. Residency Evaluation and Adherence 2012;26(1):13-7
amblyopia management, it forms the Design Study: Young ophthalmologists’
significant workload of all pediatric perception of their residency programs 11. Enyedi LB,Peterseim MW, Freedman
ophthalmology departments. There are I: Clinical and surgical skills. Ind J SF, Buckley EG refractive changes after
barriers in performing a sight restoring Ophthalmol 2017 Jun;65(6):452-460 pediatric intra-ocular lens implantation.
surgery on a child. The cost of pediatric Am J Ophthalmol
cataract surgery also significantly 2. Gogate P, Muhit M. Blindness and
higher than that in an adult36. cataract in children in developing 12. Dahan E, DrusedauMU.Choice
Piggyback IOLs are an alternative in countries. Journal of Community Eye of lens and dioptric power in
older children to correct the residual Health. 2009; 22(69):4-5. pediatricpseudophakia.JCataract Refract
refractive error (mostly myopia) as it can Surg1997;23:618 23.
be a significant error impairing unaided 3. Traboulsi El, Freedman SF, Wilson ME,
vision. Piggy back IOLs implanted Edmondson LE, Logan SA, Cheeseman 13. Prost ME. IOL power calculation
in the sulcus can provide adequate EW, Shortridge E, Trivedi RH. Cataract in cataract operations in children.
power in highly hyperopia and myopic morphology and risk of glaucoma KlinOczna2004;106:691-4.
error. IOL exchange is another option, after cataract surgery in infants with
but it’s extremely difficult in a child unilateral congenital cataract. J Cataract 14. Bothun ED, Lynn MJ, Christiansen SP,
as it poses risk for capsular rupture Refract Surg 2017;43(12):1611-12 Neely DE, Vanderveen DK, Kruger SJ,
and zonulardamage. The rrefractive Lambert SR; Infant Aphakia Treatment
formula used for piggyback IOL are 4. Sukhija J, Kaur S, Ram J. Outcome of Study.J AAPOS. 2016 Feb;20(1):49-53.
calculated purely by child’s refraction. primary intraocular lens implantation
No knowledge of the power of primary in infants: Complications and rates of 15. Trivedi RH, Wilson ME. Axial length
implant or the cause of refractive error additional surgery. J Cataract Refractive measurements by contact and
is necessary. The lens implantation Surg2016 Jul;42(7):1060-5 immersion techniques in pediatric eyes
in the ciliary sulcus is an efficient and with cataract. Ophthalmology 2011
relatively easy method. The Holladay’s 5. Gogate P, Khandekar R, Shrishrimal M, Mar;118(3):498-502
formula for Piggyback IOLs is: For Dole KD, Taras S, Kulkarni SR, Ranade
myopic eyes (One for one formula), IOL S, Deshpande M.Cataracts with delayed 16. Vasavada V, Shah SK, Vasavada VA,
power= 1 Diopter of desired spherical presentation- Are they worth operating Vasavada AR, Trivedi RH, Srivastava S,
equivalent upon? Ophthalm Epidemiology 2010; Vasavada SA. Comparison of IOL power
For hyperopia refractive error: IOL 17(1): 25-33 calculation formulae for pediatric eyes.
power= 1.5 diopter of desired spherical Eye 2016 Sep;30(9):1242-50.
equivalent 6. Mwende J, Bronsard A, Mosha M,
Gills Nomograms were developed Bowman R, Geneau R, Courtright 17. Lee BJ Predictability of formulae
P. Delay in presentation to hospital for intraocular lens power calculation
for surgery for congenital and according to the age of implantation
developmental cataract in Tanzania. Br J in paediatric cataract. Br J Ophthalmol
Ophthalmol2005;89:1478 82. 2019 Jan;103(1):106-111.

7. Gogate P, Parbhoo D, RamsonP, BudhooR, 18. Kekuniya R, et. al. Accuracy of
ØverlandL, MkhizeN, Naidoo K, Levine intraocular lens power calculation
S, du Bryn A, Benjamin L. Surgery for formulae in children less than two years.
Sight: Outcomes of congenital and Am J Ophthalmology 2012 Jul;154(1):13-
developmental cataracts operated in 19
Durban, South Africa. Eye 2016; 30: 406-
12. 19. Outcomes of Unilateral Cataracts in
Infants and Toddlers 7 to 24 Months of
8. Plager DA, Lynn MJ, Buckley EG, Age: Toddler Aphakia and Pseudophakia
Study (TAPS). Ophthalmology 2019.

20. Sukhija J, Kaur S, Ram J, Yangzes s,

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Madan S, Jinagal J. Outcome of various Sane S, Bhasa D. Unilateral congenital S, Kulkarni AN. Causes, epidemiology
Hydrophobic Acrylic Intraocular and developmental cataracts in and long-term outcome of traumatic
Lens Implantations in Children with children in India: How useful were cataracts in children in rural India. Ind J
Congenital Cataract. Eu J Ophthalmol long term outcomes of surgery. Ophthalmol 2012; 60(5):481- 4
2017; 27(6):711-15 MirajPediatricCataract Study 4. Asia Pac 33. Mboni C, Gogate P, PhiriA,Seneadza
J Ophthalmol2015; 4(6): 376-80 A, RamsonP,Manolakos-
21. Gogate P, Patil S, Kulkarni A, Mahadik TsehisiH,Musonda L, Benjamin L,
A, Tamboli R, Mane R, Borah RR, Rao 27. Tripathi S, Rishikeshi N, Tripathi S, Øverland L. Outcome of pediatric
GV. Barriers to follow-up for pediatric Kaduskar-Aney A, Taras S, Deshpande cataract surgery in Copper belt province
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Cataract study II. Ind J Ophthalmol 2014 Maharashtra. J ClinOphthalmol Res impairment and blindness in infants:
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22. Gogate P, Gilbert C. Clinical and cost 28. Cao K, Wang J, Zhang J, Yusufu M, 2011;18:109-114
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program in Western Nepal and adjacent of vitrectomy for congenital cataract Childhood blindness in developing
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V. Determinants of pediatric cataract 2019;97(3):233-39. M. Cost of pediatric cataract in
program outcomes and follow up in a Maharashtra, India. Int J Ophthalmology
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Surgy2007;33: 1775-1780 A, Kekuniya R.Precision pulse
capsulotomy: An automated alternative Corresponding Author:
24. Gogate PM, Sahasrabudhe M, Shah M, to manual capsulorhexis in pediatric
Patil S, Kulkarni AN, Trivedi R, Bhasa cataract. BMJ Open Ophthalmol2019; Dr. Parikshit Gogate
D, Tamboli R, Mane R. Long term 4(1):e000255 Dr. Gogate’s Eye Clinic, Pune,
Outcomes of Bilateral Congenital and Maharashtra, India
Developmental Cataracts Operated 30. Kaur S, Sukhija J, Ram J. Comparison of
in Maharashtra, India. MirajPediatric posterior optic capture of intraocular
Cataract Study III. Ind J Ophthalmol lens without vitrectomy vs endocapsular
2014; 62(2): 186-195 implantation with anterior vitrectomy
in congenital cataract surgery: A
25. Khanna R, Foster A, Krishnaiah randomized prospective study. Ind J
S, MehetaMK,Gogate P M. Visual Ophthalmol 2020 Jan;68(1):84-88.
Outcomes of bilateral Congenital and
Developmental Cataracts in Young 31. Kokhar SK, Tomar A, Pillay G, Agrawal
Children in South India and Causes of E. Biometric changes in Indian
Poor Outcome. Ind J Ophthalmol 2013; pediatric cataract and postoperative
62 (2): 65-70 refractive status. Ind J Ophthalmol
26. Gogate P, Patil S, Kulkarni A,
Sahasrabudhe M, Shah M, Mahadik A, 32. Gogate P, Sahasrabudhe M, Shah M, Patil DOS Times - Volume 25, Number 2, September-October 2019 35


E ect o So t ontact ens
on Intraocular Pressure

Majeedi M.Z, Gupta Y, Amitava A.K, Gupta M.
Institute of Ophthalmology, Jawaharlal Nehru Medical College, AMU, Aligarh, U.P. India.

Abstract: Purpose: The purpose of the present study is to compare the intraocular pressure done over soft contact lens and after removing
it using non-contact tonometer.
Materials and Methods: The study was conducted in Jawaharlal Nehru Medical College, AMU, Aligarh from December 2017 to July
2019. A total of 104 eyes of 52 patients were included in the study. IOP was measured over the soft contact lens using NIDEK-NT 2000 NCT
machine. Then soft contact lens was removed and IOP was again measured using same machine over the cornea without soft contact lens.
Readings were taken within an hour. The Goldmann applanation tonometer was used to record IOP without soft contact lens.
Result: In our study we found that the NCT with soft contact lens, compared to without it, measured higher on average by 0.86 mmHg,
95%CI: 0.64 to 1.08. The difference in two readings was statistically significant with p value <0.001 but it was clinically not meaningful.
Conclusion: Intraocular pressure can be accurately measured over soft contact lens. The difference is statistically significant but clinically
not significant.

The use of soft contact lenses has Figure 1: Age distribution of study population.
increased both for therapeutic and
optical purposes. They provide information important for monitoring intraocular pressures on subjects both
maximum vision and causes less the health of the eye. with and without soft contact lenses.
discomfort1. The frequent removal of To assess the IOP both with and without Goldmann applanation, the gold
contact lenses used for therapeutic soft contact lenses, we designed a standard for measuring IOP was also
purposes in corneal diseases, like study, where we have compared non- used to record the intraocular pressure
corneal ulcers, may itself lead to trauma, contact tonometry measurements of after removing contact lenses.
and adversely affect epithelialization. In
these cases where contact lens removal
is not desired, for instance in the case
of bandage contact lenses, the frequent
measurement of intraocular pressure
(IOP) may be still be needed.
The intraocular pressure (IOP) is
determined by the balance between the
rate of aqueous production from the
ciliary epithelium of the pars plicata,
and its outflow from the trabecular
meshwork and uveoscleral drainage2.
The intraocular pressure is the key
modifiable factor in almost all types
of glaucoma. Therefore its accurate
measurement is essential in every
individual. In these patients, obtaining
IOP measurements while wearing
contact lenses may provide useful

36 DOS Times - Volume 25, Number 2, September-October 2019


Table 1: Description IOP Mean (SD) Range Median Mode of <0.05 and 95% confidence interval
Variable mmHg) (mmHg) (mmHg) (mmHg) was calculated.
15.95 (2.234) 11=20 16.00 16.00
IOP via NCT with soft Results
contact lens 15.09 (2.290) 10=19 15.00 15.00
IOP via NCT without soft This study included 52 patients, both
contact lens 15.04 (2.125) 10-19 16.00 16.00 the eyes of each patient were included
IOP with Goldmann separately making a total of 104 eyes.
applanation Full ophthalmic work up was done.
Eyes with any ocular pathology except
Figure 2: Correlation of IOP with and without soft contact lens measured by NCT. refractive error were excluded from the
study. Out of the 52 patients 24 were
Table 2: Test of significance p value Mean 95% CL for mean (46.15%) female and 28 (53.8%) were
Paired t test difference difference male. The mean (SD) age of the 104
0.642-1.077 eyes was 21.29 (6.22) years; and ranged
Net with soft contact lens-Net <0.001 0.860 from 14 to 38 years (Figure 1). Out of 52
without soft contact lens 0.707-1.097 patients (104 eyes) 8 patients (16 eyes)
Net with soft contact lens-IOP <0.001 0.902 were of 18 years. The refractive error of
goldmann applanation the patients ranged from -5.0 DS to 1.0
DS with mean of -1.658± 1.526 D. Best
Material and Methods was done using same instrument. corrected visual acuity of all the eyes is
The study was conducted at Jawaharlal Goldmann Applanation was done as 6/6.
Nehru Medical College, AMU, Aligarh base line in all the patients. All the
from December 2017 to July 2019. A measurements were done three times Intraocular pressure measured over
total of 104 eyes of 52 patients using and average of the three readings were soft contact lens using non-contact
soft contact lens was included in study. recorded. The patients’ refractive error tonometry was from 11.00mmHg to
Both eyes were included separately, ranged from +1.0 D to – 5.0 D. Readings 20.00mmHg with mean (SD) of 15.95
the refractive error was also taken were taken within an hour. Patients (2.234) mmHg. The intraocular pressure
into consideration. The best corrected with systemic or ocular diseases apart measured over the cornea without soft
visual acuity was 6/6.We recorded the from refractive error or any history contact lens using NCT was 10mmHg
intraocular pressure (mmHg) using of ocular surgery were excluded from to 19mmHg with mean (SD) of 15.09
non-contact tonometer NIDEK-NT 2000 the study. The statistical analysis was (2.290). Goldmann Applanation
(NCT) machine with the soft contact done using JASP version. The tonometry range from 10 to 19mmHg
lens in situ. Then the soft contact lens difference was taken significant if the with mean of 15.04 (2.125) mmHg
was removed and again the reading statistical difference in data had p value (Table 1).

The NCT with soft contact lens,
compared to without soft contact
lens, measured higher on average
by 0.86 mmHg, 95% CI: 0.64 to 1.08.
The difference in two readings was
statistically significant with p value
<0.001 (Table 2, Figure 2). The IOP
measured over soft contact lens via
NCT was compared with Goldmann
applanation done without soft
contact lens again the p valve was
statistically significant (p<0.001) with
a mean difference of 0.902 mmHg,
95%CI: 0.70 to 1.09. We also derived a
formula through the regression line
for estimating intraocular pressure
without soft contact lens when the
measurement is actually done over
the soft contact lens i.e. IOP measured
without soft contact lens = 0.738 + 0.856
x IOP measured with soft contact lens. DOS Times - Volume 25, Number 2, September-October 2019 37


Figure 3: Bland Altman Agreement plot. readings was statistically significant No significant difference was found
with p value <0.001. On Bland - Altman when the difference between the
On Bland-Altman agreement plotting, agreement plotting, the NCT with readings of pressure with soft contact
the NCT with soft contact lens measured soft contact lens measured more than lens and without soft contact lens was
more than without soft contact lens, on without soft contact lens, on average compared with the variation in the
average by 0.9 mmHg, with 95% CI: 0.68 by 0.9 mmHg, with 95% CI: 0.68 to 1.12. refractive error(power of soft contact
to 1.12 (Figure 3). Not surprisingly this is the exact result lens), p= 0.088. They showed a poor
we obtained from the paired t-test, since correlation(r=0.165), only 2.8% of the
The calculated difference in IOP they are essentially doing the same variation is explained with change in
(mmHg) between the two reading i.e. thing. It stands to logic, that a mere the power of the lens.
IOP measured over soft contact lens and difference of 0.9 mm Hg may not be Conclusion
IOP measured without it via NCT, was clinically meaningful. Intraocular pressure over soft contact
assessed with respect to refractive error Willium C Panek et al.3 in 1990 found lens can be accurately measured using
of patient (the power of soft contact that no significant difference between non-contact tonometer over soft contact
lens). It has poor correlation of 0.165. the readings of intraocular pressure lens without removing it for all clinical
The variation is only 2.8% explained over soft contact lens and without purposes. The difference in pressure
by the power of the lens (D) and is not soft contact lens. They summarized values is though statistically significant,
statistically significant (p=0.088). that there was 82% chance of getting but clinically not meaningful. For
a pressure difference of 1 mmHg. This more precise measurement IOP can be
Discussion study was conducted on Tono-pen for calculated using the formula derived.
The NCT measurements with and intraocular pressure measurement The results of this study are true only
without the soft contact lenses showed a and Plano T contact lens (Bandage soft for non-contact tonometer. Other
significant correlation Spearman’s rho, contact lens). In our study we also found instruments of IOP measurements
r = 0.878, p<0.001. We found 77% of the the difference of 0.9mm Hg higher over are needed to be evaluated before
variation is explained by the soft contact the soft contact lens, though it was implementation.
lens or we can say 23% of this variation statistically significant but clinically References
remains unexplained. On paired not meaningful. 1. Fırat PG, Cankaya C, Doganay S,
t-test, the NCT with soft contact lens,
compared to without, measured higher Cavdar M, Duman S, Ozsoy E, et al. The
on average by 0.86 mmHg, 95%CI: 0.64 influence of soft contact lenses on the
to 1.08; p<0.001. The difference in two intraocular pressure measurement. Eye.
2012 Feb;26:278–82.
2. Bowling B, Kanski JJ. Kanski’s clinical
ophthalmology: a systematic approach.
8. ed. Elsevier 2016; 917 p.
3. Panek WC, Boothe WA, Lee DA,
Zemplenyi E, Pettit TH. Intraocular
Pressure Measurement With the
Tono-Pen Through Soft Contact
Lenses. American Journal of
Ophthalmology.1990 Jan; 109:62–5.

Corresponding Author:

Dr. Majeedi M.Z. MS
Institute of Ophthalmology, Jawaharlal Nehru
Medical College, AMU, Aligarh, U.P. India.

38 DOS Times - Volume 25, Number 2, September-October 2019


OCT- Angiography in Age Related
Macular Degeneration

Tanya Jain, Rahul Mayor
Shroff Charity Eye Hospital, Darya Ganj, New Delhi, India.

Age-related macular degeneration Figure 1: Showing loss of choriocapillaris due to which the large choroidal vessels are seen at
(AMD) is a leading cause of irreversible the area of choriocapillaris.
visual loss worldwide. Although is the
third cause of blindness worldwide, it Optical coherence tomography (OCT) the same location of the retina. The
is the first in industrialized countries1. is currently the primary method to degree of decorrelation in signal is then
The pathogenesis of AMD has been monitor for structural changes, such calculated. This enables visualization
implicated to be inflammation, as neovascular membranes, fibrosis, of the moving part only, assumed to
oxidative damage which increases intraretinal and subretinal fluid, and correspond to the endoluminal flow of
with age along with influence of the pigment epithelial detachments. erythrocytes within the bloodstream.
genetic and certain environmental Optical coherence tomography is easier The above procedure is then repeated
factors. However, growing research and faster to acquire than FA, does not for a series of different Y-positions in the
and understanding into the disease require invasive injections, and provides retina to achieve the three-dimensional
suggests the role of choroidal and cross-sectional and en face images of data set, from which proprietary
retinal circulation in the development retinal and choroidal features however algorithms such as split-spectrum
of drusen, with hypoxia implicating sometimes it difficult to delineate the amplitude-decorrelation angiography
progression of the disease in such eyes2. membrane and even more difficult to (SSADA), optical microangiography and
Clinically it is classified into 2 main differentiate it from a subretinal scar OCT angiography ratio analysis are used
types: or fibrosis. Based on the location of to reconstruct en face angiograms6,7.
Non-exudative (also known as “dry” or CNVM complex, Exudative AMD can
“non-neovascular”) be classified into Type 1, 2 and 3. OCTA in Dry AMD
Exudative (“wet” or “neovascular”) OCTA detects differences in amplitude, Geographic atrophy-
Severe vision loss occurs primarily intensity or phase variance between OCTA shows choriocapillaris flow
due to 2 processes: geographic atrophy a series of sequential B-scans taken at impairment under the regions of GA
in advanced nonexudative AMD and
choroidal neovascularization (CNV)
in exudative AMD culminating in
Traditionally fundus fluorescein
angiography (FFA) has been used
to monitor the development of the
exudative AMD and leakage and to
monitor the response to therapy. Its
greatest utility is in showing dynamic
changes in fluorescent patterns, such as
leakage, staining and pooling, as well as
dye transit time to the eye. Based on FFA,
the exudative AMD can be classified
into- Classic and Occult types4. DOS Times - Volume 25, Number 2, September-October 2019 39


Figure 2: Showing comparison of FFA and OCTA. CNV net is not obscured by overlying 1. Presence of a tangle of vessels in
haemorrhage and dye leakage. a well-defined shape (lacy-wheel,
glomerular, sea fan, etc).
Figure 3: Showing presence of loops, peripheral arcades and a hypointense halo surrounding
the lesion suggestive of an active lesion. 2. Presence of anastomoses or loops
branching in numerous tiny
Figure 4: Showing a chronic CNV. capillaries,

(Figure 1)8,9,10. In these areas, larger thickness in these patients thereby 3. Presence of a peripheral arcade.
choroidal vessels may be displaced into strengthening the hypothesis of 4. Presence of a hypointense halo.
the area ordinarily occupied by the hypoxia induced damage in these eyes. The non-invasive nature of OCTA allows
choriocapillaris and may be seen on the comprehensive lesion monitoring after
en face OCTA image at the depth level OCTA in Wet (exudative) AMD treatment with anti-VEGF compounds.
where the choriocapillaris is ordinarily The major advantage of OCTA is that Sequential examinations can shadow
seen. OCTA image is not obscured by dye morphological changes in the
leakage and a clear depiction of the CNV neovascular network, closely tracking
Intermediate AMD is obtained. The neovascular network is the timings of vascular network
Early detection of membranes where visualised as it is as is shown in (Figure remodelling in patients undergoing
no leakage is seen in FFA and no 2). treatment with anti-VEGF (Figure 5).
exudation/fluid pockets on OCT in eyes Characteristic features suggestive of an
with intermediate AMD11,12. There is active CNV net OCTA in retinal angiomatous
reduced vascular density and choroidal proliferation (RAP) lesions
Qualitative and quantitative analyses
of type 3 neovascular complexes can
be performed using OCTA. Querques
et al13 evaluated the features of RAP
lesions and found lesions emerging
from the deep capillary plexus, forming
a clear, tuft-shaped, high-flow network
in the outer retinal segment in all
eyes, abutting in the sub-RPE space
(Figure 6). The authors also reported
a small, clew-like lesion present in
the choriocapillaris and that, in some
cases, this clew-like lesion seemed to
be connected to the choroid through a
small-caliber vessel. In fact, compared
with conventional imaging, OCTA may
improve the detection and delineation
of vascular changes occurring in type 3

The polyp detection rate is about 40
%.14 On OCTA following features are
noted (Figure 7)-

1. Hyperflow (nodular areas)
2. Branched vascular networks
3. Hypo area surrounded by hyper

However, due to atypical flow pattern in
polyps, ICGA remains the gold standard
diagnostic imaging tool, especially in
cases with atypical signs or treatment

40 DOS Times - Volume 25, Number 2, September-October 2019


managing and monitoring of AMD and
other retinal diseases. Reading centres
around the world are beginning to work
with this technology and the inclusion
of OCTA images in clinical trials will
most likely lead to the advent of OCTA
biomarkers of AMD progression and
treatment response.


1. Jager RD, Mieler WF, Miller JW. Age-
related macular degeneration. N Engl J
Med 2008; 358 (24): 2606-2617

2. Remsch H, Spraul CW, Lang GK, Lang GE.

Changes of retinal capillary blood flow
in age-related maculopathy. Graefe’s
archive for clinical and experimental
ophthalmology = Albrecht von Graefes
Archiv fur klinische und experimentelle
Ophthalmologie. 2000;238(12):960-4.

Figure 5: Showing resolution of peripheral arcading with Anti-VEGF and then reappearance. 3. hor(s) 2017 Reprints and permissions: / journals Permissions.

4. Cole ED, Novais EA, Louzada RN,
Waheed NK. Contemporary retinal
imag- ing techniques in diabetic
retinopathy: a review. Clin Exp
Ophthalmol. 2016;44:289–299.

5. Huang D, Swanson EA, Lin CP, et al.
Optical coherence tomography. Science.

6. Gao SS, Jia Y, Zhang M, Su JP, Liu G,
Hwang TS, et al. Optical Coherence
Tomography Angiography.
Investigative ophthalmology & visual
science. 2016;57(9):OCT27-36.
Figure 6: Showing hyper flow clew like lesion in the deep capillary plexus.
7. Tan ACS, Tan GS, Denniston AK, Keane
PA, Ang M, Milea D, et al. An overview
of the clinical applications of optical
coherence tomography angiography.
Eye. 2017.

Figure 7: Structural OCTA showing peaked PED, Cross- sectional OCTA showing a high 8. OCTA shows choriocapillaris flow
flow area corresponding to the red dot and Enface OCTA showing a hyperflow area (yellow impairment under the regions of GA.8,9
circle) with adjacent Branched vascular network (BVN). nta A, Casselholm de Salles M, Amren
U, Bartuma H. Optical Coherence
Tomography Angiography of the
Foveal Microvasculature in Geographic
Atrophy. Retina. 2017;37(5):936-42.

response. of tools to quantitative evaluate vessel 9. Waheed NK, Moult EM, Fujimoto
The constant software updates and density, perfusion/non perfusion, JG, Rosenfeld PJ. Optical Coherence
technical enhancements are making etc increased the usefulness and Tomography Angiography of Dry Age-
OCTA devices faster, more precise and trustworthiness of OCTA. This will Related Macular Degeneration. Dev
ultimately more reliable. For instance, further reduce the use of conventional Ophthalmol. 2016;56:91-100.
the introduction of 3D projection angiographic systems, turning OCTA
artifact removal and the incorporation in the gold standard for diagnosis, 10. Optical Coherence Tomography
Angiography in AMD | www.amdbook.
org [Internet]. 2019
[cited 29 November 2019]. Available DOS Times - Volume 25, Number 2, September-October 2019 41


from: 13. Querques G, Miere A, Souied EH. Optical Corresponding Author:
Coherence Tomography Angiography
11. Palejwala NV, Jia Y, Gao SS, et al. Features of Type 3 Neovascularization in Dr. Tanya Jain
Detection of nonexudative choroidal Age-Related Macular Degeneration. Dev Shroff Charity Eye Hospital,
neovas- cularization in age-related Ophthalmol. 2016;56:57-61. Darya Ganj, New Delhi, India.
macular degeneration with optical
coherence tomography angiography. 14. Cheung C, Yanagi Y, Akiba M, Tan A,
Retina. 2015;35:2204–2211. Mathur R, Chan C Et Al. Improved
Detection And Diagnosis Of Polypoidal
12. Roisman L, Zhang Q , Wang RK, et Choroidal Vasculopathy Using A
al. Optical coherence tomography Combination Of Optical Coherence
angiog- raphy of asymptomatic Tomography And Optical Coherence
neovascularization in intermediate Tomography Angiography. Retina.
age-related macular degeneration. 2019;39(9):1655-1663.
Ophthalmology. 2016; 123:1309–1319.

42 DOS Times - Volume 25, Number 2, September-October 2019


A Case of Congenital Deformity-
Optic Disc Pit with Associated
Maculopathy and Isolated
Choroidal Coloboma

Mushriff Supriya, Goynka Yashaswi
Index Medical College Hospital and Research Centre, Indore

Optic disc pits are rare congenital Serous detachment of macula is the Figure 1: Fundus picture.
anomalies result from imperfect closure most common complication of optic
of superior edge of the embryonic disc pit and occurs in 25-75% of these Figure 2: OCT Disc and Macula.
fissure usually associated with macular cases.
serous detachment. The incidence of optic disc pit has been Figure 3: OCT showing Neurosensory
Coloboma is the absence of part of an reported about one in 11,000 without Detachment.
ocular structure as a result of incomplete gender predilection1,2. Visual defects are common.
closure of embryonic fissure. Ori in o OD -M ui
IDA Mann assi cation Four different possible sources have
Case History Type 1: coloboma extending above the been proposed for the fluid seen in the
A 32 year old female from indore anatomic disc intraretinal and subretinal spaces in
presented with sudden painless Type 2: coloboma extending up to the
diminution of vision in left eye since 10 superior border of disc
days. Type 3: coloboma extending below the
There were no other ocular complaints lower border of disc
and no systemic illness. Type 4: coloboma involving the disc
LE Fundus examination - revealed only
optic nerve head with grey round Type 5: coloboma present below the
excavation on temporal side and sharp disc with normal retina above and
circumscribed white area largely below the coloboma
devoid of blood vessels in the inferior Type 6: pigmentation present in the
fundus S/o choroidal coloboma grade 5 periphery
according to Ida Mann classification. Type 7: coloboma involving only the
OCT LE – revealed neurosensory periphery
detachment from underlying retinal
pigment epithelium. Signs
Visual acuity is normal in absence of
Discussion complications.
Optic pit, described for the first time by Disc is often larger than normal, usually
Wie the in 1882. contains a greyish round or oval pit of
Optic disc pit is rare congenital cavitary variable size usually temporal.
anomaly of the optic disc. DOS Times - Volume 25, Number 2, September-October 2019 43


ODP-M. Intravitreal gas injection. 7. Ohno-Matsui K, Hirakata A, Inoue M,
The first possible source of fluid is the Akiba M, Ishibashi T (2013) Evaluation
vitreous3,4. Macular buckling surgery. of congenital optic disc pits and optic
The second possible source of fluid disc colobomas by swept-source
is the cerebrospinal fluid (CSF), Pars plana vitrectomy8,9,10,11. optical coherence tomography. Invest
which has been proposed to enter the Ophthalmol Vis Sci 54:7769–7778.
intra- and sub-retinal spaces from the References
subarachnoid space through the ODP 1. Kranenburg EW (1960) Crater-like holes 8. Cox MS, Witherspoon CD, Morris
defect5,6,7. RE, Flynn HW (1988) Evolving
The third possible source of fluid is in the optic disc and central serous techniques in the treatment of macular
leakage from blood vessels at the ODP. retinopathy. Arch Ophthalmol 64:912– detachment caused by optic nerve pits.
The fourth possible source of fluid is 924. Ophthalmology 95:889–896.
from the choroid, through the Bruch’s 2. Georgalas I, Ladas I, Georgopoulos G,
membrane and peripapillary atrophy. Petrou P (2011) Optic disc pit: a review. 9. Schatz H, McDonald HR (1988)
Graefes Arch Clin Exp Ophthalmol Treatment of sensory retinal detachment
Diagnosis 249:1113–1122. associated with optic nerve pit or
Clinical 3. Sadun AA, Khaderi KH (2013) Optic coloboma. Ophthalmology 95:178–18.
OCT disc anomalies, pits, and associated
FFA serous macular detachment. In: Ryan SJ, 10. Snead MP, James N, Jacobs PM
Schachat AP, Wilkinson CP, Hinton DR, (1991) Vitrectomy, argon laser, and
Treatment Sadda SR, Wiedemann P (eds) Retina, gas tamponade for serous retinal
Spontaneous resolution occurs in upto 5th edn. Elsevier Health Sciences, UK, detachment associated with an optic
25% cases. pp 1583–1588. disc pit: a case report. Br J Ophthalmol
No treatment is usually initiated if an 4. Sugar HS (1964) An explanation for the 75:381–382.
optic. acquired macular pathology associated
disc pit is seen without maculopathy. with congenital pits of the optic disc. 11. Lee KJ, Peyman GA (1993) Surgical
Management is in form of laser Am J Ophthalmol 57:833–835 management of retinal detachment
photocoagulation or surgery. 5. Krivoy D, Gentile R, Liebmann JM, associated with optic nerve pit. Int
Stegman Z, Rosen R, Walsh JB et al Ophthalmol17:105–107.
(1996) Imaging congenital optic disc
pits and associated maculopathy using Corresponding Author:
optical coherence tomography. Arch
Ophthalmol 114:165–170. Dr. Mushriff Supriya
6. Rutledge BK, Puliafito CA, Duker JS, Hee Index Medical College Hospital and Research
MR, Cox MS (1996) Optical coherence Centre,
tomography of macular lesions Indore, M.P. India.
associated with optic nerve head pits.
Ophthalmology 103:1047–1053.

44 DOS Times - Volume 25, Number 2, September-October 2019

Subspeciality-Neuro-ophthalmology Strabismus

The Role of Part Time Occlusion in
Treatment of Amblyopia

Subhash C.Dadeya, Surabhi Shalini
Guru Nanak Eye Centre, Maulana azad Medical College, New Delhi, India

Amblyopia has been described in increasing age. However, all children supported by many authors in the past.
various ways in ophthalmology. should be considered for treatment of However, the popularity, it commands
Amblyopia was first described by amblyopia regardless of age. among the clinicians is not always
Hippocrates in 400 B.C. The word shared by the patients and their parents.
“Amblyopia” has been derived from Treatment of amblyopia remains Major failure to therapy is because of
the Greek words, ‘Amblyos’ and ‘ops’ a therapeutic challenge to the poor compliance. Hence, the recent
meaning dull vision1. One of the trends are in favor of part time occlusion
most succinct definition has been ophthalmologists both as regards to its because of the better compliance6.
attributed to Von Graefe, who defined diagnosis and management. Various
amblyopia as the condition in which treatment options have been tried for Problems associated with full time
observer sees nothing and patient very management of amblyopia. These are: occlusion
little. However, clinically, amblyopia Refractive correction only, Occlusion Full time occlusion therapy is not
has been described as unilateral or therapy, Penalization, Pharmacological without side effects, which in turn
bilateral reduction in best-corrected therapy, Refractive Surgery, binocular affects the compliance associated
visual acuity caused by form vision treatments in the form of modified with it. A major concern is occlusion
deprivation and/or abnormal binocular dichoptic videogames, pleoptics, amblyopia1. The better eye, because
interaction, without a visible organic CAM stimulator, acupuncture, of long duration of occlusion, remains
cause commensurate with this visual trancranial magnetic brain deprived of sensory stimulus and
loss1. A best corrected central visual stimulationetc. However, they are still develops amblyopia.
acuity less than 20/40 is labelled as to find their rightful place in amblyopia
bilateral amblyopia and a difference of management. Also, children find it socially
two or more lines between normal and embarrassing to wear the patch owing
amblyopic eye is required to classify it Occlusion to the cosmetic blemish associated
as unilateral amblyopia. Amblyopia, till with it. Allergic skin rash caused by
date, remains a diagnosis of exclusion. There is neither a substitute nor a patching may also hamper the patient
This visual loss is correctable, if shortcut for occlusion in the treatment willingness of putting the patch.
appropriate measures are applied at of amblyopia. Full time occlusion has
appropriate time2. been considered the gold standard Another problem with full time
in management of amblyopia. The occlusion, particularly in severe
Management French naturalist and botanist Comte amblyopia is the functional debilitation
It is crucial to treat amblyopia as early as de Buffon3 (1707-1788) is often credited that it causes, especially early in
possible, as not only does it reduce the with having introduced treatment for treatment, as the child’s better eye is
visual quality of the patient, but there amblyopia as a patching of the fixating occluded. Poor vision during occlusion
is also a significant risk of suffering eye. However, occlusion was actually of the sound eye presents a significant
severe disability from injury to the one described much earlier by the scientist deterrent to good compliance. The child
good eye. Amblyopia can be treated ThabitIbn Qurrah4 from Mesopotamia may require additional supervision to
effectively in the first decade of life, around 900 AD. Sattler5 reintroduced avoid accidental injury. This causes
greater success being achieved when occlusion treatment. significant stress to the child and his
therapeutic measures are instituted family. Occlusion also causes fusion
at the earliest as the success rates of Duration of occlusion disruption and increase in angle of
amblyopia treatment may decline with There is no consensus over the duration deviation. All these adverse effect
of patching. Different authors have associated with the occlusion therapy
recommended different duration of
patching. Full time occlusion has been DOS Times - Volume 25, Number 2, September-October 2019 45

Subspeciality-Neuro-ophthalmology Strabismus

are more pronounced with the full time A. Is minimal intensity patching (two weeks of occlusion therapy (P< 0.001).
occlusion. These significantly decrease hours/day) as effective as moderate Seventy-three (73%) of the total 100
the compliance with the therapy which, intensity patching (six hours/ eyes responded to amblyopia therapy
in turn, compromises the success. day) in the treatment of moderate with 11 eyes (44%), 17 eyes (68%), 22
amblyopia (20/40 to 20/80)9. eyes (88%) and 23 eyes (92%) being
Role of part time occlusion amblyopia responders in the four groups
In view of drawbacks of full time B. Is full time patching (all waking respectively. They concluded part-time
hours) more effective than part occlusion therapies are comparable to
occlusion treatment, part-time time patching (six hours/day) in full-time occlusion in effectiveness of
occlusion treatment has been tried treating severe amblyopia (20/100 treatment for mild, moderate and severe
by various authors and results are to 20/400)10. amblyopia.
promising6-11. The recent trends are in
favour of part time occlusion because of A total of 189 patients between 3 to 7 Hence, recent studies recommend
the higher compliance associated with years were enrolled and followed up for part time occlusion for treatment of
it. four months. At the 5 week visit, visual amblyopia, both in terms of efficacy and
acuity had improved from baseline by compliance.
Park et al7 evaluated the outcome of the an average of 1.84 lines and at 4 months,
6 hours occlusion with near activities in 79% of the patients in the two hour References
monocular amblyopic patients among group and 76% of the patients in six 1. VonNoorden GK, Campos EC. Binocular
Korean population. He noted significant hour group had improved by an average
improvement in visual acuity with part of 2.4 lines. There was no significant vision and ocular motility: Theory and
time occlusion. At the end of patch difference in the side effect profile management of strabismus. 6th ed St.
therapy, visual acuity improved from ranging from decrease in acuity in sound Louis: Mosby; 2002.p. 246-97.
baseline by an average of 3.2 ± 2.5 lines. eye, changes in ocular alignment and
stereoacuity. The Amblyopia treatment 2. vonNoorden GK. Mechanism of
In a study done by Awan M etal8, index questionnaire was considered for amblyopia: Doc Ophthalmol. 1977;
comparision was made between three both groups and scores were similar in 34:93.
groups – no patching, three hours the two on adverse effects subscale and
patching, and six hours patching. treatment compliance subscale but on 3. Buffon M de: Dissertation surla cause du
They have recorded a significant social stigma subscale, the two hour strabismeou des yeuxlouches. HistAcad
improvement in 3 hours and 6 hours group fared better than the six hour R Sci. 1743:231
patching group as compared to control group. It was concluded that minimal
group. Before patching, Snellen’s VAs patching (2 hours/day) is as effective 4. Qurrah TI. Vision and perception:
was 0.23, 0.17, and 0.22 in amblyopic as moderate patching (6 hours/day) in Translated and edited by Wafai
eyes. The mean (SD) improvement the treatment of moderate amblyopia MZ. Riyadh, Saudi Arabia: Obiekan
over the 12 weeks period was 1.6 lines and prescribing greater number of publishing house; 1991.
(0.12), 1.9 lines (1.0), and 2.3 lines (1.2) hours of patching does not seem to
for groups 1,2, and 3, respectively. have significant beneficial effect during 5. Sattler CH. Erfahrungenuber
They also investigated compliance the first four months of treatment9. die Besertigung der Amblyopie
with patching therapy by recording Further the study concluded that for und die Wiederherstellung des
the effective patching time using severe amblyopia, part time patching binokularenSehaktesbeiSchielenden. Z
occlusion dose monitor (ODMs). They (six hours) and full time patching are Augenheilkd. 1927; 63:19.
noted better compliance with shorter equally effective in patients 3 to 7 years
duration of patching. The mean (SD) of age10. 6. Scheiman MM, Hertle RW, Beck RW,
compliance in the 3 and 6 hour groups Edwards AR, Birch E, Cotter SA, et
was 57.5% (30.8%) and 41.2% (30.9%). Singh I et al11, in their prospective al. Pediatric eye disease investigator
Initial amblyopia was found to have interventional case series, compared group. Randomised trial of treatment of
influence over compliance as children the efficacy of part-time versus full-time amblyopia in children aged 7 to 17 years.
with worse VA were most reluctant to occlusion for treatment of amblyopia Arch Ophhalmol. 2005; 123:437-47.
wear the patches. in older children aged 7-12 years.
They divided their study population 7. Park KS, Chang YH, Na KD, Hong S,
Recent recommendations of Pediatric in 2 hour, 4 hour, 6 hour and full time Han SH. Outcomes of 6 Hour Part-
Eye Disease Investigator Group (PEDIG) patching groups. All four groups time Occlusion Treatment Combined
support part time occlusion and rate it (two hours, four hours, six hours and with Near Activities for Unilateral
similar in efficacy to full time occlusion. full time occlusion therapy) showed Amblyopia. Korean J Ophthalmol. 2008;
The ATS29,10 was initiated to address the significant visual improvement after 18 22(1):26-31.
following questions-
8. Awan M, Proudlock FA, Gottlob I.A
randomized controlled trial of unilateral
strabismic and mixed amblyopia using
occlusion dose monitor to record
compliance. Invest Ophthalmol Vis Sci.
2005 Apr; 46(4):1435-9

9. Repka MX, Beck RW, Holmes JM,

46 DOS Times - Volume 25, Number 2, September-October 2019

Subspeciality-Neuro-ophthalmology Strabismus

Birch EE, Chandler DL, Cotter SA, et al. for treatment of severe amblyopia Corresponding Author:
Pediatric Eye Disease Investigator Group. in children. Ophthalmology. 2003;
A randomized trial of patching regimens 110(11):2075-87. Dr. Subhash C.Dadeya
for treatment of moderate amblyopia Guru Nanak Eye Centre,
in children. Arch Ophthalmol. 2003; 11. Singh I, Sachdev N, Brar GS, Kaushik Maulana Azad Medical College,
121(5):603-11. S. Part time occlusion therapy for New Delhi, India.
amblyopia in older children. Indian J
10. Holmes JM, Kraker RT, Beck RW, Birch Ophthalmol. 2008 Nov-Dec; 56(6):459-
EE, Cotter SA, Everett DF, et al. Pediatric 63.
Eye Disease Investigator Group. A
randomized trial of patching regimens DOS Times - Volume 25, Number 2, September-October 2019 47


MN Read Test- Measuring Reading

Punita Kumari Sodhi MS
Guru Nanak Eye Centre and Maulana Azad Medical College, New Delhi, India

Reading speed is an objective measure of 40 cm, with subject wearing near refractive Figure 1: MN Read Test.
reading performance. Research has shown correction.
that patients, with either normal or low so that it corresponds to reading speed
vision, often require letters that are two or Components of Continuous-Text (assuming no reading errors were made).
three times larger than their acuity limits Charts for Eye Exams The horizontal scale on the plotting paper
before they can achieve their maximum shows logMAR print size (Figure 3).
reading speeds. Solely assessing letter size The MNREAD charts are composed of Typically, reading time remains fairly
that can be read for evaluating the near 19 sentences that decrease in print size constant for large print sizes. But as the
visual acuity (VA) of patients with low from logMAR 1.3 to logMAR -0.5 (Snellen acuity limit is approached, there comes
vision is inadequate.1 This is because a equivalent of 20/400 or 6/120 to 20/6 a print size where reading starts to slow
person’s reading access depends on both the or 6/2). Every sentence is 60 characters
range of print sizes that can be recognized long (anything that takes up a ‘space’ is
visually and the reading speeds for those a character; words are units of characters
print sizes. Hence reliable and valid text- without a space interrupting them), printed
based reading charts are required to assess in three lines, and is at a standard level of
reading performance in low vision patient difficulty, using vocabulary from a third
population. grade reading level (Figure 1). The passages
resemble normal everyday reading and
Measuring reading speed contain simple linguistic content. The
luminance should be at least 80 candela
The MNREAD Acuity Charts are continuous per square metre (cd/m2). When using
text reading acuity charts to measure the MNREAD Chart the patient is asked
reading speed as a function of print size in to read the passages aloud as quickly and
persons with normal and low vision.2 These accurately as possible at viewing distance of
were developed at the Minnesota Laboratory 40 cm. A blank piece of card should be used
for Low Vision Research, University of to cover the sentences below the one being
Minnesota by Steve Mansfield, Gordon read (to prevent the patient previewing the
Legge, Andrew Luebker and Kathryn subsequent sentences).
Cunningham. The MNREAD Acuity Charts
can be used to measure reading speed at A stopwatch is used to record the time taken
different print sizes, and hence, can be used to read each sentence (to the nearest 0.1
to determine the print size which supports second). A note is made of the time taken
the patient’s maximum reading speed. on the score sheet; and any words that are
The charts are used to assess how reading missed or read incorrectly. These variables
performance depends on print size. The text are used to determine the smallest size of
is printed in high contrast. The print style is print at which the patient can successfully
similar to that found in many newspapers read a passage and the print size that
and books. It is used for testing adults and supports the patient’s maximum reading
children from age eight years and up. speed. This is an objective measurement of
a patient’s reading performance. (Figure 2)
Testing procedure shows the score sheet.

Measuring reading speed is combined with The reverse side of the score sheet carries
the reading-acuity measurement. During graph paper for plotting reading-speed data.
examination of subjects, distance visual It is not necessary to calculate reading speed
acuity (VA) is evaluated with a ETDRS for the sentences if this plotting paper is
distance vision chart. Near vision is also used, as it measures in words per minute.
measured on near vision ETDRS chart. The scale on the vertical axis is reading time
Following this, the reading performance is given in terms of reading speed in words-
evaluated on the MNREAD charts viewed at per-minute. This scale has been transformed

48 DOS Times - Volume 25, Number 2, September-October 2019

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