dos_July_2014

Delhi
Ophthalmological
Society

Contents

5 Editorial Miscellaneous

Expert’s Corner 65 Goniosynechiolysis: Remedy for Synechial
Angle Closure
17 Angle Closure Glaucoma Deven Tuli

Theme: Glaucoma Evolution

25 Concurrent Phacoemulsification and 67 Evolution of Glaucoma Surgery
Glaucoma Valve Implantation in Cases of Sonal Dangda, Kirti Jaisingh, Yashpal Goel,
Coexisting Cataract and Glaucoma Amrit, Shraddha Saraf
Brig J.K.S. Parihar
39 Circumferential Trabeculotomy Using PG Corner
an Illuminated Microcatheter: A New
Treatment for Primary Congenital Glaucoma 71 Pathophysiology of Angle Closure Glaucoma
Tanuj Dada, Shreyas Temkar, Reetika
47 Sharma, Dewang Angmo, Shikha Gupta, Kirti Jaisingh, Sonal Dangda
Ramanjit Sihota
Ganglion Cell Complex Scan for Monthly Meeting Corner
Comprehensive Assessment of Glaucoma
51 Rupsanchita H. Das, Manoj Rai Mehta 77 Phakic IOLs in Correcting Refractive Errors
Post- Penetrating Keratoplasty Glaucoma
Mainak Bhattacharyya, Neha Rathie, Rajesh Hans
Ritu Arora, Parul Jain
Tear Sheet

Diagnostics 91 Anti-Glaucoma Medications
Nalini Saxena, Supriya Arora, Prateeksha
Sharma, Usha Kaul Raina

57 Posterior Segment Imaging in Glaucoma

Anita Ganger, Viney Gupta

www. dosonline.org l 3

“With the new day comes new strength and new thoughts”.
-Eleanor Roosevelt

Respected Seniors & Dear Friends,
It is the start of a new calendar year for the activities of Delhi Ophthalmological
Society. And it brings with it a new sense of freshness. After having a perfect
time for introspection into our work in the last year its time to set the bars
further higher. Its time to strive further with all energy within to reach the
goals set by the society. This year DOS Winter Conference would see a more
intense academic discussion with the theme being “Cases & Controversies in
Ophthalmology”. It will involve case presentations and debates on difficult
clinical scenarios that often lead to diagnostic and management dilemmas.
DOS Teaching Programme was conducted on 14th and 15th June 2014, which
was very well attended and the academic content was highly appreciated by
one and all. It was structured to create an excellent learning environment
with best of teachers, innovators, and visionaries in the various subspecialties
of ophthalmology which benefitted hundreds of participants from all over the
country.
The DOS calendar years first clinical monthly meeting was held at Safdarjung
hospital and was well attended. It had a right combination of futuristic
technology in ophthalmology along with present day challenging scenarios
in our day-to-day clinical practice. We hope all the further clinical meetings
in this calendar year for DOS will be well attended. The last issue of DOS
Times on Clinical Trials was a new initiative that was appreciated by a lot
of members as it provided them an overview into evidence based clinical
practice. I hope to bring newer and innovative ideas this year so that all
members may maximally benefit.
Sincerely Yours

Rajesh Sinha
Secretary,
Delhi Ophthalmological Society

www. dosonline.org l 5

Guest Editorial Editorial BGolauacrodma

Primary Angle Closure DOS EEdditiotroiarl-iBno-carhdief
Glaucoma
Rajesh Sinha
On the dawn of the 21st century angle closure glaucoma
has gained increased attention. This is not surprising, Executive Editor
since the rationale for the epidemiological classification
proposed by Foster et al. made very clear how to call Vijay Kumar Sharma
angle closure patients and how to tell them apart. Tarun Arora
Angle closure is a fascinating subject. It requires a high
level of suspicion, attention to detail and commitment Editorial Board
to the patient and with their families and their potential
affected members; it also requires expending an extra time exploring present and past Ritika Sachdev
symptoms, use of drugs that modify the anterior chamber and the iris, and it even requires Sandeep Gupta
us to imagine and verify what happens to the eye and angle when the lights are turned off Ramendra Bakshi
and the night reigns.
Calling angle closure glaucoma a nocturnal disease might not be such an exaggerated claim. Neelima Aron
It frequently begins with intermittent closures, most of them symptomatic, and nocturnal in Digvijay Singh
nature. But the symptoms are usually disregarded and attributed to stress, lack of sleep, Manpreet Kaur
migraines, etc., and might not even be referred to as ocular by the patient. Hemant Kamble
The patient will adapt to morning headaches because they will go away when the lights are Vishnukant Ghonsikar
turned on, at least at the beginning. In some cases the patient that has had classic,diurnal,
pulsatile migraine with aura since youth, might start having nocturnal or morning, non- Ravi B.
pulsatile headaches with nausea and still attribute them to a worsening migraine. Shorya Vardhan Azad
A “simple” ophthalmological examination that includes dark-room gonioscopy will confirm
changes in the angle, intermittent closures and signs of previous crisis, but the eye of the Anirudh Singh
beholder must be trained for those subtle signs. The eyes cannot see what the brain does Vinod Agarwal
not know, but only at the beginning. After performing gonioscopy routinely, the keen mind will
start to recognize patterns and become a better and faster detector, and then confirmer, of Neha Goel
any impending angle closure. The benefits of a timely diagnosis of angle closure cannot be Parul Jain
underestimated. In cases where symptoms and angle closure are present, but no optic nerve Reetika Sharma
damage, IOP elevation or synechiae can be demonstrated; the chronic, recurrent headaches
are a main reason for patient suffering, with direct impact on the quality of life. They are DOS Correspondents
usually younger patients that have months or even years of pain, brain scans, analgesics
and migraine medications. Making the correct diagnosis and performing angle-opening Supriya Arora
procedures might suddenly and dramatically improve their quality of life. Prateek Kakkar
Of course, having diplopia caused by an iridotomy can also have a deep impact on quality of Ruchir Tewari
life, and in a patient with no glaucoma damage the risk of this and other complications should Vineet Sehgal
be carefully considered. In patients with optic nerve damage the balance of the risks of an
iridotomy will always be trumped by the fact that patients with untreated angle closure will Nasreen
worsen, despite topical medications (except maybe pilocarpine) and an apparently low IOP, Ravish Kinkhabwala
because, in these cases, darkness will only cause more Darkness.
Pulak Agarwal
Dr. Oscar Albis-Donado Akshay Tayade
MD Glaucoma Assistant Professor, Vaiteeshwaran L.
Instituto Mexicano de Oftalmologia,
Querétaro, México Amar Pujari
Obuli Ramachandran
Cover Designed by: Aman Dua
Layout Designed by: Mahender Advisory Board
Published by Dr. Rajesh Sinha for Delhi Ophthalmological Society
Printers: K.D. Printo Graphics, 2/20, 1st Floor, D.D.A. Market R.V. Azad Rajendra Khanna
Complex, Near SBI, Dr. Ambedkar Nagar, New Delhi, Y.R. Sharma Atul Kumar
Email: [email protected] B. Ghosh Lalit Verma
B.P. Guliani J.S. Titiyal
Harbansh Lal Sanjeev Gupta
V.P. Gupta A.K. Grover
Ramanjit Sihota Mahipal S. Sachdev
Praveen Malik Amit Khosla
Abhishek Dagar Namrata Sharma
P.K. Sahu Umang Mathur
J.K.S. Parihar J.S. Bhalla
Tanuj Dada Rohit Saxena
Bhavna Chawla Manisha Agarwal
Ruchi Goel Rohan Chawla

www. dosonline.org l 7

Delhi
Ophthalmological
Society

Executive Members

Rajendra Khanna DOMS Cyrus M. Shroff MD Rajesh Sinha MD, FRCS Neeraj Sanduja MS Sanjeev Gupta MD
President Vice President Secretary Joint Secretary Treasurer

[email protected] [email protected] [email protected] [email protected] [email protected]

M. Vanathi MD Vipul Nayar DOMS, DNB, MNAMS Tinku Bali MS, FRCS Bhavna Chawla MS Rajib Mukherjee DOMS, DNB
Editor Library Officer Executive Member Executive Member Executive Member

[email protected] [email protected] [email protected] [email protected] [email protected]

R.P. Singh MD Neeraj Manchanda DO,DNB Manisha Agarwal MS Deven Tuli MS Arun Baweja MS
Executive Member Executive Member Executive Member Executive Member Executive Member

[email protected] [email protected] [email protected] [email protected] [email protected]

Namrata Sharma MD Ajay Aurora MS J.S. Titiyal MD Rohit Saxena MD Ashu Agarwal MS
DOS Representative to AIOS DOS Representative to AIOS Ex-Officio Member Ex-Officio Member Ex-Officio Member

[email protected] [email protected] [email protected] [email protected] [email protected]





6th DOS Teaching Programme

14th & 15th June, 2014 (Saturday & Sunday)

Jawaharlal Auditorium, AIIMS, Ansari Nagar, New Delhi

6th DOS Teaching Programme

14th & 15th June, 2014 (Saturday & Sunday)

Jawaharlal Auditorium, AIIMS, Ansari Nagar, New Delhi



Membership Benefits

Become a member of the Delhi Ophthalmological Society now and
get the combo benefit: Complimentary registration DOS Winter
Conference 2014& DOS Teaching Programme January 2015.

With a total membership of over 7500 members, the Delhi Ophthalmological Society is one of the largest state ophthalmic
societies in the world. The strength of our society is excellent academics in the form of regular academic programmes
including monthly meetings, Winter Conference, Subspeciality Meetings, International DOS Conference (I-DOS) & Annual
Conference.
Member Benefits of Delhi Ophthalmological Society:
1. Get DOS Times Magazine- Monthly
2. DJO Scientific Journal -Quarterly
3. Get free access to the members section of website.
a. Access Digital Directory of Members
b. Access to past issues of DOS Times
c. Access to hundreds of hours of surgical videos, talk and recordings of past conferences, workshop and meetings.
4. Discounted registration fees for national and other conferences of DOS.
5. Access to full text articles of numerous international journals through OVID available at the DOS Library.
6. Attend DOS Teaching Programme for PG Students, a structured resident training module.
7. Fellowships National & International Travel Grants.
8. Delhi Ophthalmological Society is one of the largest state ophthalmic societies in the world.
9. The strength of our society is excellent academics in the form of
a. Regular Academic programmes
b. Monthly Meetings, Winter Conference
c. I-DOS
d. Annual Conference
10. DOS Times (Monthly news and views bulletin) & Delhi Journal of Ophthalmology (Quarterly Scientific Journal).
11. Receive Digital Directory of Members.
12. Wet Labs: Hand on training modules for acquiring clinical and practical skills.

Download application from the website www.dosonline.org
For all your queries and questions: E-mail at [email protected] or visit Website : www.dosonline.org

DOS Secretariat

Dr. Rajesh Sinha

Secretary

Delhi Ophthalmological Society

Room No. 479, 4th Floor, Dr. R.P. Centre for Ophthalmic Sciences,
AIIMS, Ansari Nagar, New Delhi, Delhi, India

Tel.: +91-11-26588074 w Email: [email protected] w Web.: www.dosonline.org

Experts’ Corner

Angle Closure Ramanjit Sihota
Glaucoma Lingam Vijaya

Even though angle closure disease is less common than open angle glaucoma worldwide, its S.S. Pandav
incidence in Indian population is known to be much higher than previously documented. Also, its Tanuj Dada
impact on quality of life of the patient is more critical due to a greater likelihood of blindness, and Colin I. Clement
higher morbidity than in patients with open angle glaucomas. An accurate and timely diagnosis is Oscar Albis Donado
therefore essential, in order to prevent progression to irreversible visual field loss.
This expert opinion interface aims to clarify certain doubts, as well as elucidate basic strategies for
the diagnosis and management of angle closure disease. The questions have been prepared by Dr.
Shibal Bhartiya (SB) Consultant, Glaucoma Services, Fortis Memorial Research Institute, Gurgaon,
Haryana, India

Dr. Ramanjit Sihota (RS): MD, Professor, R.P. Centre for Ophthalmic Sciences, All India
Institute for Medical Sciences, Ansari Nagar, New Delhi, India.

Dr. Lingam Vijaya (LV): MBBS, MS, Director, Smt. Jadhavabai Nathmal Singhvee Glaucoma
Services, Sankara Nethralaya, 18 College Road, Chennai, India

Dr. S.S. Pandav (SSP): Professor Ophthalmology, Advanced Eye Center, Postgraduate Institute
of Medical Education & Research, Chandigarh, India.

Dr. Tanuj Dada (TD): MD, Professor, R.P. Centre for Ophthalmic Sciences, All India Institute
for Medical Sciences, Ansari Nagar, New Delhi, India.

Dr. Colin I. Clement (CIC): B.Sc. (Hon), MBBS, PhD, FRANZCO, Glaucoma Unit, Sydney
Eye Hospital, Australia, The University of Sydney, Australia, Eye Associates, Sydney, Australia

Dr. Oscar Albis-Donado (OAD): MD Glaucoma Assistant Professor, Instituto Mexicano de
Oftalmologia, Querétaro, México

SB: What is the role of ASOCT/UBM in diagnosis of primary angle closure disease?
RS: ASOCT could be used as a screening tool. UBM is currently, largely a research tool.
LV: Dynamic evaluation of the angle is possible with these devices and definitely useful
for research studies. One cannot see beyond what we see with gonioscopy using ASOCT.
ASOCT tells us whether angle is occludable or not that to in four quadrants, one will need
Swept source OCT for more information. Using UBM the anatomy beyond iris can be studied
such as plateau iris and iris cysts. In clinical practice well done gonioscopy still is the gold
standard.
SSP: ASOCT and UBM are useful to study the anatomical relationship between various
structures at the AC angle. ASOCT is easier to do and shows how open or closed the angle is.
However, it cannot image ciliary body adequately. UBM has the advantage of imaging ciliary
body. Both can be used to quantify objectively the degree of angle closure.

None of these replaces gonioscopy, which remains the preferred method for assessing
anterior chamber angles. I use UBM to study the cause of angle closure if goniocsopy suggests
plateau iris, iris cysts or other anterior segment anomaly. UBM is particularly useful if rotation
of ciliary body or cilio-choroidal effusion is suspected to be causing angle closure.

TD: For diagnosis of Primary Angle closure Disease you require to perform a good
gonioscopic examination of the anterior chamber angle in a dark room with a small slit which
should not cross the pupil and should not rely on ASOCT/UBM. UBM is helpful to confirm

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Experts’ Corner

a diagnosis of suspected Plateau iris or secondary angle SB: What is your choice of medical therapy in
closure due to pigment epithelial cysts of the iris. ASOCT / PACG patients?
UBM are indicated if corneal opacification prevents a view
of the angle and ASOCT is especially useful for non-contact RS: Prior to an iridotomy, pilocarpine 2% Q8H. after
information regarding early post operative complications an iridotomy, medical therapy would depend on the ‘target’
after filtering surgery in PACG. IOP assessed as in POAG, and the socioeconomic status of
the pt, but a prostaglandin would be the most efficacious.
CIC: Anterior segment imaging such as ASOCT may
be used to assess the relationship between peripheral iris LV: Presume they had initial YAG PI. Treatment will
and the trabecular meshwork in eyes suspected of angle be like POAG. Pilocarpine has a definite role in eyes with
closure and compliments, but does not replace, the plateu iris.
gonioscopic findings. Gonioscopy has advantages over
imaging as it provides a dynamic 360 degree assessment SSP: I do laser iridotomy for all angle closure
of the angle, it is cheap and readily available. However, glaucoma patients followed by medical treatment. After
imaging may be advantageous in individuals that are laser iridotomy, I use anti-glaucoma medicines depending
intolerant of gonioscopy (eg: severe blepharospasm) on the level of IOP and existing damage. Generally I would
or in whom gonioscopy may be very difficult (eg: small start with a prostaglandin analogue and add a beta-blocker
palpebral aperture, tarsorrhaphy). In some health care if required. If IOP is still high I would add another drug
systems, continuity of care with the same practitioner is such as brimonidine or topical CAI and start discussing
not possible and interpretation of previously documented with the patient about other alternatives like iridoplasty or
gonioscopy findings may be difficult or unreliable. Imaging incisional surgery especially, if there is moderate to severe
would prove very useful under these circumstances as it visual field damage already.
provides highly repeatable and objective measures of the
angle anatomy. TD: The first step is to perform a laser iridotomy, and
in the presence of a patent iridotomy the management is
The main advantage of UBM is its ability to obtain similar to primary open angle glaucoma. Prostaglandins
images of tissues deep to the iris plane including the ciliary are the first choice and timolol/brimonidine can be used
body and choroid. Although I do not routinely use UBM in as second line therapy. If a laser iridotomy has not been
PAC assessment, it may be helpful in circumstances where performed, a plateau iris syndrome is diagnosed post PI or
secondary causes of angle closure including ciliary body the IOP is not controlled medically post PI with the patient
masses, aqueous misdirection and uveal effusion syndrome not willing/fit for surgery – pilocarpine is helpful in these
are suspected. situations.

OAD: UBM is a very useful tool to ascertain some CIC: All patients should receive pilocarpine to
cases of ciliary body cysts or tumours. It is also very address the pupil block until more definitive treatment is
helpful to document the amount of angle opening before available - either Laser iridotomy or cataract surgery. Don’t
an iridotomy is performed and to measure the effect of forget to assess and treat the fellow eye as the condition
such iridotomy in opening the angle. As it is a dynamic is usually bilateral. Pilocarpine is not ideal long-term
and video-based imaging modality, it can also show live because of the frequency of dosing required, intolerance
changes in the angle anatomy under different illumination (particularly young patients) as well as induced nyctalopia
conditions and with indentation. and restricted visual field.

ASOCT will also serve these purposes, but it usually Otherwise, for long term IOP control I have no
does not permit differentiating tumours from cysts, since the specific preference for medical therapies in angle closure.
penetration of light is limited by iris pigment and thickness. I select treatment based on efficacy, dosing frequency,
On the other hand, it gives a much more detailed view of affordability and patient specific contra-indications. Most
the angle, and is especially good at showing Schlemm’s initial treatment will be with a prostaglandin analogue,
canal, the scleral spur and even collector channels. It being followed by beta-blockers (fixed combination or separate
a non-contact method that can be performed with the dosing) then carbonic anhydrase inhibitors or alpha
patient in a sitting position, in light or dark conditions (since agonists.
focusing is done with an infrared camera), and although it
usually does not have video capabilities, it can certainly OAD: In patients with a patent iridotomy and
measure several times under different conditions. ASOCT persistent elevated IOP my choices in medical treatment
can be especially useful in patients that are uncooperative follow mostly the same parameters as for POAG patients:
during gonioscopy, and in those cases where we are not first PG analogues, then beta-blockers, CAI inhibitors
sure if we are changing angle anatomy during gonioscopy and alpha 2 agonists, depending on systemic and ocular
by inadvertently indenting with a 4-mirror lens or pulling contraindications. I will also consider using pilocarpine,
with a 3-mirror Goldman type lens. especially if the angle didn’t fully open and I am considering
either an iridoplasty or phaco (with or without a filtering
procedure) in the near future.

18 l DOS Times - Vol. 20, No. 1 July, 2014

Experts’ Corner

SB: What is the indication of performing laser trial in the UK and Asia - the so called “EAGLE”study.
iridotomy in patients with primary angle closure Certainly attempting to remove pupil block makes sense
disease? but it is less certain whether cataract extraction or Laser PI
is superior for achieving this.
RS: All patients with a diagnosed PACD must undergo
an iridotomy, as it prevents further relative pupillary block Regardless of whether there is synechial or
and therefore one cause of trabecular damage. This will not appositional angle closure, laser PI has been shown to
affect a chronically raised IOP. reverse (at least in part) the irido-trabecular contact and so
should be considered in all cases of angle closure. Ravi
LV: In PACS indications for PI are – not willing to Thomas published a series of 70 or so eyes showing this
come for periodic gonioscopy, family history of angle was the case.
closure, one who requires periodic dilatation of the pupils
for retinal evaluation and people who have difficulty in A word of caution: uncommonly eyes with extensive
accessing medical facility. Iridotomy is must for PAC and irido-trabecular contact may develop worse IOP control
PACG following laser PI, presumably due to the heavy pigment
load +/- hyphaema deposited onto the remaining
SSP: I do laser iridotomy for all patients with primary functioning trabecular meshwork.
angle closure (PAC) and primary angle closure glaucoma
(PACG). For angle closure suspects (PACS), I do iridotomy OAD: Consideration must be given to potential
if patients does not have easy access to medical care, in problems caused by an iridotomy before deciding on
one eyed patients with very shallow anterior chamber and performing it on a patient that has no glaucoma damage. We
patients who need frequent pupillary dilation for other should balance the increased risk of cataract, uveitis, corneal
ocular conditionsuch as diabetic retinopathy. damage, monocular diplopia and other complications with
the risk of developing glaucoma damage. In some cases
TD: Laser iridotomy is mandatory in all cases of of PACD I prefer to perform the iridotomy regardless of a
primary angle closure glaucoma, primary angle closure, normal IOP and a healthy optic nerve:
acute attack of ACG, fellow eye of acute attack of ACG
as a first line treatment. This basically means that if the • Patients that have morning headaches, with or
angle is occludable in primary position (180 degrees of without halos or nausea.
the pigmented trabecular meshwork not visible ) with
evidence of peripheral anterior synechiae, pigment clumps • Patients with subtle signs of intermittent closures
indicating previous irido-trabecular contact or raised (loss of pupillary ruff, sectorial iris atrophy, circumferential
IOP – go ahead with a laser iridotomy. In PAC Suspects iris atrophy, patchy trabecular pigmentation that coincides
who only have an occludable angle without other signs/ with a peak in the peripheral iris, pigment dispersion on the
symptoms an iridotomy may be done at the discretion of endothelium or over the iris).
the ophthalmologist if there is a family history of PACG,
one eyed patients, patients who need repeated dilatation • Some patients with recurrent subconjunctival
for fundus evaluation and those who have poor access to haemorrhages and no other symptoms.
ophthalmic care and cannot come for follow up.
• Patients with first-degree relatives with PACG,
CIC: Most protocols for the treatment of acute angle more so if they are blind or had the need for a filtering
closure would include laser PI as part of initial treatment. procedure.
This is because laser PI can reverse the pupil block and
result in widening of the iridocorneal angle and IOP SB: How do you manage patients with persistently
reduction. However, treatment without laser PI is possible raised IOP after laser iridotomy with a healthy optic
as has been shown with the Hong Kong protocol consisting nerve?
of topical pilocarpine and beta-blocker, laser iridoplasty
and early cataract extraction. This is just as quick if not RS: As 30 % of these are likely to progress to a
quicker at bringing the acute attack under control and may glaucomatous neuropathy, I would prescribe medical
result in better long-term IOP reduction. The advantage of therapy to reduce the IOP below 18 mmHg.
treatment including laser PI is that may be completed in a
single admission with the patient discharged the same day. LV: Look for the cause for persistent IOP rise. It can
The later strategy may require a longer hospital admission be plateau iris or POAG or some other cause such as
or multiple admissions as well as the availability of an steroid use for something else etc. Management depends
operating theatre. up the cause for the raise. If the cause is due to residual IOP
rise (most often due to PAS or microscopic damage to TM)
Its role in chronic angle closure is less certain; this is following PI needs treatment like POAG.
currently under investigation in a multi-centre randomised
SSP: If the IOP remains high after laser iridotomy,
I would re-examine the patient to ascertain the cause of
high IOP. I would do gonioscopy to check if the angle is

www. dosonline.org l 19

Experts’ Corner

open or still closed. If open consider possibility of open LV: Not easy, trabeculectomy becomes mandatory
angle glaucoma (POAG, Pigmentary, Pseudoexfoliative, in eyes with clear lens. In such a situation one has to take
steroid induced etc.) or mixed mechanism glaucoma. If the all the possible precautions to avoid aqueous misdirection.
angle is closed look for the causes like peripheral anterior Use of IV mannitol helps in reducing the volume, tight
synechiae, neovascularization of the angle, plateau iris. sutures helps in forming the AC. If lens shows evidence
I would monitor IOP and treat it like OHT if the angles of cataract a combined surgery or only cataract surgery
have opened up. If angles do not open, my threshold for (depending upon damage) is preferable.
starting medical treatment would be much lower and
would consider iridoplasty if IOP remains in high twenties SSP: I would consider existing visual field damage,
or thirties. level of IOP, rate of progression if available, age of the
patient, previous experience with medicines and status of
TD: These patients are at high risk for developing crystalline lens while making a treatment plan. Generally
irreversible optic neuropathy and must be started on medical I would start with a prostaglandin analogue and add other
therapy as indicated earlier. If the IOP is not controlled drugs if required, and monitior IOP and visual fields. If IOP
medically or the patient is not compliant or cannot afford is not controlled satisfactorily or fields show progression, I
medications – an early lens extraction in expert hands is would consider iridoplasty or incisional surgery to further
helpful in anatomically opening the angle, reducing both lower IOP.
IOP and the requirement for medications and preventing
disease progression. However the requirement for reading TD: I use medical therapy in such patients to initially
glasses and long term follow up must be explained to the control the intraocular pressure and follow these patients
patient. with visual fields and other imaging modalities (OCT/
HRT) to look for progression. If the IOP is not controlled
CIC: If there is cataract present, perform phaco- medically or there is evidence of disease progression –
emulsification with IOL implant +/- goniosynechiolysis surgery is indicated. Since the patient has a 20/20 acuity
depending on the gonioscopic findings on the table this is a tricky situation with no clear guidelines from peer
following the cataract surgery. If there is no cataract but reviewed literature. There are 3 options – trabeculectomy
the angle remains compromised despite the PI, I perform alone, phacotrabeculectomy, or clear lens extraction. In
iridoplasty and supplement with medical therapy until IOP patients over 50 years of age with advanced / near total
control is achieved. If the angle has opened in response cupping – I would do a phacotrabeculectomy with MMC,
to PI but the IOP remains elevated, medical therapy is the while in patients with early/moderate glaucomatous optic
treatment of choice. In this situation, if 180 degrees or more neuropathy, I would perform a sequential surgery – stage 1
of angle is open, Laser trabeculoplasty may be possible. would be a temporal clear lens extraction with IOP being
controlled medically and stage 2 (preferably after 6 months)
If despite the above measures the IOP remains at a would be a trabeculectomy with MMC if the IOP is not
level that may either lead to a retinal vascular occlusion or controlled medically. In any patients just taking out the
optic nerve compromise, then flitration surgery is warranted. lens reduces the IOP and the patient can be maintained on
Trabeculectomy with mitomycin C is my surgery of choice medical therapy.
in this circumstance.
In younger patients with good near vision the choice
OAD: If the angle is open I manage them as I would is much tougher and I would perform a trabeculectomy
manage a patient with ocular hypertension, deciding on with MMC and releasable sutures to avoid post operative
therapy based on the risk of developing glaucoma damage shallow anterior chamber.
as per OHTS results (IOP, cup to disk ratio, CCT, etc.). If
the angle is still closed, in a young patient I will perform CIC: The same as question 4. I would stress that
a diode laser iridoplasty, but if it persists or if it is an older cataract may be present despite an acuity of 20/20 so
patient I will move on to perform a phaco. If the IOP is cataract surgery with goniosynechiolysis can be justified
very high I will usually combine the phaco with a filtering even though acuity is perceived to be normal.
procedure (I prefer MIGS).
OAD: The angle might not open with a patent
SB: How do you manage patients with PACG with iridotomy, so again I will check gonioscopy in a very dark
high IOP, patent iridotomy with 20/20 visual acuity? room, or measure the angle with ASOCT and check for
plateau iris. If it is present I will first perform iridoplasty,
RS: A baseline diurnal phasing provides us with 14 to 18 shots on the peripheral iris that change angle
information regarding the highest IOP that has to be configuration, and use medical therapy. In these cases I will
reduced, at which time point the IOP is highest and the not use prostaglandin analogues until the inflammation has
amount of IOP fluctuation. This together with an evaluation disappeared (at least a month).
of the extent of the neuropathy and other risk factors would
determine my ‘target IOP, as for POAG.

20 l DOS Times - Vol. 20, No. 1 July, 2014

Experts’ Corner

If the patient has 20/20 and is close to a neutral Ideally a glaucoma surgeon should be equally
refraction with no residual angle closure I will manage with proficient in both glaucoma and cataract surgery otherwise
topical medications, as mentioned above, and might even personal expertise in one surgery will govern the decision
consider SLT in some of them. making process !!

If the patient is over 40 and has 20/20 with a significant CIC: I personally try to avoid combined cataract
refractive error, presbyopia or a bit of lens opacity, with surgery and trabeculectomy as the former compromises
high IOP and residual angle closure, I will usually perform a the outcome of the later, the survey is technically more
glauco-refractive surgery, usually a phaco-canaloplasty and difficult than either procedure alone and a complication at
consider using monovision. I will avoid multifocal lenses any stage during the surgery has ramifications for all other
since patients with glaucoma damage will already have aspects of the procedure. In the first instance addressing
compromised contrast sensitivity. I will also avoid toric the cataract and correcting angle anatomy may confer good
lenses since although induced corneal astigmatism is low, IOP control. I would therefore suggest phaco-emulsification
it is also unpredictable in both magnitude and direction. with IOL combined with goniosynechiolysis. This is shown
Accomodating IOL might be considered, but they might to be effective in this (reference).
also behave unpredictably, especially if the patient has
pseudoexfoliation associated to PACG. Patients should have gonioscopy“ on-the-table”
at the completion of the case to assess the angle. Any
SB: In patients with advanced PACG with co- area of synechial angle closure should be corrected with
existing cataract what is your preferred choice of goniosynechiolysis followed by intracameral miochol,
surgery? postoperative pilocarpine 2% QID and on day 1 iridoplasty
to help prevent PAS reforming.
RS: Any advanced glaucoma management has
priority over cataract surgery. I would reduce the IOP to OAD: If the angle opens with indentation gonioscopy
‘target’ levels by medication/surgery first, and follow this or if the synechiae are not extensive, I will perform phaco-
later by a cataract surgery. Patients have to be counselled canaloplasty with goniosynechiolysis if after removing the
regarding the irreversible loss due to glaucoma, and are cataract and implanting the IOL any are remaining. If this
content to wait for the cataract surgery. is not the case I will usually perform phaco-trabeculectomy
or phaco-Ahmed valve, depending on what the patient can
LV: If there is significant optic disc changes with field afford, but my preference is for the Ahmed valve in patients
changes and extensive PAS prefer to do combined surgery. that have difficulty in attending control visits or have a high
If the damage is not significant and PAS is not extensive risk of infections.
only cataract surgery will be sufficient.
SB: Is there a role of laser trabeculoplasty and
SSP: Choice of surgery would depend on IOP control laser iridoplasty in your management of patients with
and amount of visual impairment due to cataract. If IOP is angle closure?
well controlled with one or two anti- glaucoma medicines,
I would just do cataract surgery and monitor IOP. If IOP is RS: In a study at R P Centre, laser trabeculoplasty
not controlled but cataract surgery can wait for 3-6 months, after an iridotomy, in PACG did show some drop in IOP,
I would do glaucoma surgery only. I would do combined but most pts needed additional medications.
surgery in case cataract surgery cannot wait and IOP is also
not controlled adequately. LV: Following YAG PI if the angle has widened with
good access and laser trabeculoplasty is needed one can
TD: I prefer a two stage surgery over combined definitely try it. If the angle is closed with PAS or access
surgery in advanced PACG with co-existing cataract as to trabecular mesh work remains very narrow it is not a
the inflammatory response in such patients can accelerate good idea to do laser trabeculoplasty. There are number of
fibrosis and lead to failure of trabeculectomy. Many of studies in literature about the role of laser trabeculoplasty.
these eyes have small pupils requiring iris manipulation,
may have zonular weakness and require a longer exposure Laser iridoplasty is an accepted procedure for angle
to ultrasound energy. Combined surgery has higher closures that have not opened up with YAG PI and specially
complications as compared to cataract surgery alone, but in plateu iris. Again there is enough evidence in literature
the IOP must be controlled medically if only the cataract about its role and possible problems. In my practice I do
surgery has been done. consider it in plateu iris, however use of pilocarpine once
or twice a day is a simple alternative (provided patient
On a practical note performing phacoemulsification tolerates).
in a PACG eye with operated trabeculectomy is a
much difficult and hazardous option (esp. Increased SSP: I do laser iridoplasty when IOP remains high
corneal endothelial cell loss) as compared to performing after acute attack and laser iridotomy does not work. Also,
trabeculectomy in a pseudophakic PACG eye. if IOP remains high after iridotomy in PAC even after LI and

www. dosonline.org l 21

Experts’ Corner

topical medicines and angles are still occludable. In PACG IV mannitol to deturgese the vitreous half an hour preop.
if IOP is not controlled and patient is nor keen on surgery. All eyes should have releasable sutures applied, so that
shallow anterior chambers can be avoided in the early
TD: Thanks for asking one easy question – the answer postop period.
is NO.
LV: Eyes with angle closure are likely to have
CIC: This has already been discussed. crowded anterior segment and shallow orbit. These
OAD: I will only consider selective laser features makes the eye prone for per operative issues such
trabeculoplasty in my patients with wide open angles as iris prolapse, shallow anterior chamber and tense eye
on dark-room gonioscopy, and never argon laser ball following local anaesthesia administration (even with
trabeculoplasty. On the other hand I perform iridoplasty minimal amount of anaesthetic agent). To avoid these issues
regularly for cases where the angle remains occludable, one possible way out will be to give a hyperosmotic agent
symptoms persist and/or plateau iris configuration is seen such as intravenous mannitol. This reduces the volume and
with a patent iridotomy. minimises the chances of iris prolapse and shallow anterior
SB: Is there a role of goniosynechiolysis in chamber. Iris prolapsed through the trabeculectomy stoma
management of a PACG? may result in very large peripheral iridectomy, to avoid this
RS: Peripheral anterior synechiae are associated with one can use intraoperative miotic to constrict the pupil and
organic changes and damage to the trabecular meshwork, have a required size iridectomy. However it is not a good
therefore synechiolysis is unlikely to restore this function in idea to use miotic such as pilocarpine. Pilocarpine can shift
chronic cases. the iris lens diaphragm anteriorly which in turn can cause
LV: It is an useful adjuctive procedure along with shallow anterior chamber in the post operative period. One
cataract surgery in angle closures. This per se can open up can avoid this by using the minimum required dose and
the angle and control the intraocular pressure. One should irrigating the pilocarpine thoroughly out of the eye.
keep in mind PAS can recur and IOP control also depends
up on extent of trabecular dysfunction. SSP: PACG patients have a tendency for shallow AC
SSP: I do goniosynechiolysis sometimes during and aqueous misdirection. AC should be kept formed during
cataract surgery in cases with PACG. I am not sure if works surgery as far as possible and the scleral flap should be
in my hands. Goniosynechiolysis in advanced cases of closed tightly. Conjunctival closure should be meticulous
PACG does not guarantee a normally functioning trabecular to avoid wound leak and post-operative swallowing of AC.
meshwork.
TD: I have recently started to perform intraoperative TD: Start with a prayer !!. Preoperatively the
Goniosynechiolysis after lens extraction in PACG eyes with intraocular pressure should be low – use mannitol. Always
early/moderate disease. It may be helpful in eyes where the use releasable sutures as shallow AC post trabeculectomy
PAS are not long standing. It is a nice surgery to perform in PACG can lead to a vicious cycle of complications.
as you can actually observe the iris being peeled off the
trabecular meshwork which gives the surgeon a good CIC: If surgery is performed soon after an angle
feeling !! closure attack, there is likely to be ocular inflammation
However the evidence for its usefulness is anecdotal which increases the risk of subconjunctival fibrosis and
and we await ongoing RCTs to resolve this issue. trabeculectomy failure. Eyes should be treated with steroid
CIC: Please see my response to question 6. for a minimum of 1/2 before surgery. My typical regimen
OAD: I believe goniosynechiolysis is an integral consists of g. Prednefrin Forte QID.
part of PACG surgery in both glauco-phaco-refractive and
phaco-filtering procedures, since any remaining trabecular My usual trabeculectomy technique includes the
function in the freed areas will assist the main filtering creation of a small PI but in this instance I would advocate
surgery we choose. Goniosynechiolysis is an effective way a large PI as these eyes are at increased risk of developing
of decreasing the number of medications needed for IOP post-operative aqueous misdirection. The large PI allows
control in patients that have had surgery for PACG. for a YAG anterior hyaloidotomy if needed whereas this
SB: Any special pearls while performing would not be possible with a small PI.
trabeculectomy in PACG patients?
RS: Please reduce the IOP with medications as In eyes with a very short axial length (eg: <20mmHg),
much as possible for a few days prior to surgery and give I would consider performing sclerotomies in the inferonasal
and inferotemporal quadrants as further prophylaxis to
guard against this complication.

Post-operatively, eyes should receive g. Atropine 1%
tds to prevent aqueous misdirection.

OAD: Try to avoid anterior chamber collapse at
all times, use either an AC maintainer or viscoelastic if

22 l DOS Times - Vol. 20, No. 1 July, 2014

Experts’ Corner

necessary. When performing the peripheral iridectomy SSP: Express shunt needs space in AC for its insertion,
make sure to grab only iris, if an inadvertent cut of the therefore, it is not preferred for angle closure glaucoma.
ciliary band is made the eye will be more prone to both
bleeding and aqueous misdirection. Making a more TD: The ExPRESS implant is contra-indicated in
anterior, descemetic window, under the trabeculectomy phakic PACG. We have used the implant in a few eyes
flap will decrease chances of this accident, and this might during phacotrabeculectomy and in PACG eyes post
be very useful for surgeons with partial colour blindness cataract surgery, however our results have not been
that cannot easily tell apart the iris from the ciliary band in encouraging and we have stopped using the device. The
dark irises. ExPRESS implant is essentially equal in safety and efficacy
to conventional trabeculectomy in published western
SB: Can the use of OLOGEN implant replace literature but at a huge cost and a new set of complications
MITOMYCIN C in trabeculectomy? to deal with. At the moment the use of ExPRESS in glaucoma
surgery is largely governed by economic reasons without
RS: OLOGEN does not appear to have the efficacy of much scientific merit !!
MMC in Indian eyes.
CIC: Personally, I would strongly discourage the
LV: Thereotically there is no contraindication for use of the Express glaucoma implant during filtration
OLOGEN implant in angle closure. Indication for it surgery for elevated IOP due to primary angle closure.
depends upon surgeon’s choice. In general terms it offers no real advantage over a good
trabeculectomy technique yet it costs considerably more
SSP: I don’t think Ologen is a replacement for MMC. and results in a permanently placed metallic foreign body
MMC trabeculectomy has a higher success rate but with within the eye. In the case of primary angle closure, there
significantly more bleb related problems. I would use is a risk of pigment dispersion or corneal decompensation
Ologen when risk of failure is about mild to moderate. For secondary to implant iris or implant corneal touch
eyes with high risk of failure I would still use MMC. respectively. The likelihood of corneal decompensation is
further compounded by a reduction in the health of the
TD: Ologen implant is not a substitute to MITOMYCIN corneal endothelium that typically accompanies an angle-
C although there are reports in literature of equal efficacy. closure attack. I have removed a number of Express shunts
In our experience Ologen alone does not give satisfactory because of corneal decompensation for this exact reason
results – esp. if low target IOP is required. However we have and in at least 1 case, corneal transplantation was required.
used ologen implant at both subconjunctival and subscleral
(under the sclera flap) in combination with low dose OAD: As an alternative to trabeculectomy in
MMC (0.1mg/ml for 1 min) for eyes with advanced optic combined Phaco it is very useful. If the patient can afford
neuropathy and got good results. The basic hypothesis is to it, or the health system will cover it and you have previous
reduce Mitomycin C complications and modulate wound experience in POAG eyes then it is a valid option. I do not
healing with ologen. This remains an issue for debate and recommend its use in phakic patients, even if they have a
we await further studies to give us a better understanding patent iridectomy, since the tip of the implant will still rub
on the use of Ologen. on the iris, and besides, any remaining angle closure will
potentially cause IOP spikes when irido-trabecular contact
CIC: I do not use the Ologen subconjunctival implant is present. An EXPRESS implant can also be combined
for any glaucoma surgery. with manual small incision cataract surgery (SICS) in a
more predictable manner than a trabeculectomy, so in
OAD: Yes, Ologen has become a very useful adjuvant a case of advanced glaucoma and advanced or high-risk
to filtering procedures, safer than mitomycin, but still, you cataract a temporal SICS and a supero-nasal EXPRESS might
might need to use both in some patients in order to reach outperform more conventional approaches.
very low target IOPs.
DOS Correspondent
SB: Any role of the EXPRESS implant in PACG? Shibal Bhartiya MS
RS: The EXPRESS implant forms the osteum, and this
is too small for adequate IOP control in most PACG eyes
requiring surgery.
LV: Wide open angle is a must for Express implant. If
there is angle closure it is not a good idea to insert Express
implant and it can get occluded with the iris.

www. dosonline.org l 23

Concurrent Phacoemulsification and Glaucoma Valve GlaGulacuocomma
Implantation in Cases of Coexisting Cataract and Glaucoma
Brig J.K.S. Parihar

SM, VSM, MS, DOMS, DNB, FAMS

Brig J.K.S. Parihar, SM, VSM**, MS, DOMS, DNB, FAMS
Army Hospital (Research & Referral) Delhi Cantt, Delhi

Management of coexisting cataract and glaucoma attracted invention of an ideal alternative devices to control
particularly in cases of refractory glaucoma associated non responsive glaucoma.
with cataract is a highly complex situation in which In 1906, Rollet and Moreau had placed horse hair through
conventional Phacotrabeculectomy has been found to be a corneal paracentesis in an attempt to drain a hypopyon
disappointing particularly in cases of refractory glaucoma. externally.
The term refractory glaucoma is being used for any kind of The first translimbal glaucoma drainage device (GDD),
glaucoma which has not responded to medical or surgical reported by Zorab in 1912, was silk thread used as a
treatment and need subsequent surgical re- intervention. seton to aid drainage of anterior chamber fluid to the
The peculiarities involved with deranged anatomical subconjunctival space.
configuration, physiology and dynamics of aqueous In 1969, Molteno introduced the concept that a large
circulation in these cases are far different from the surface area was needed to disperse the aqueous beneath
other glaucoma patients and were found to have highly the conjunctiva.
disappointing outcome. Such complexity further adds In 1973, Molteno improved his device with the idea of
to the limited and short term success despite repeated draining the fluid away from the source to increase the
surgical intervention in the form of trabeculotomy or success rate. He introduced the Molteno implant with a
combined modulated trabeculectomy and trabeculotomy. long silicone tube attached to a large end plate made up
Since the usual line of management both medical and of polymethyl methacrylate placed in the subconjunctival
surgical procedures have invariably proved ineffective in space around 9-10 mm posterior to the limbus. All the
this particular glaucoma group, the application of various currently available GDDs are based on this concept by
glaucoma drainage devices have been tried in recent past, Molteno.
however such devices were not accepted in general due to Ahmed Glaucoma Drainage implant (Valve)
complexity of procedure, constraints of follow up as well Nonvalvular designs of initial GDD was the major constrains
as bioacceptance of valve material and design itself. The and inhibition towards wide acceptance of GDD as useful
newer generation drainage devices have been found to measure to control nonresponsive glaucoma. Uncontrolled,
have significant qualitative improvement in terms of design excessive filtrations leading to significant and threatening
and materials as well. These changes have encouraged complications were genuine concern. This has triggered the
wider acceptance of such devices in refractory glaucoma need of valved (restrictive) device. Early nineties witnessed
including as concurrent primary procedure. the modification and gradual transformation of free pass
Historical background of Glaucoma drainage device (nonrestrictive) into valved (restrictive) device.
devices Dr. Mateen Ahmed a US based medical engineer from
Surgical procedures for glaucoma remained an uneven Central India is pioneer who developes a unique restrictive
road until trabeculectomy was introduced for adult onset valvular device, which consists of a receptacle plate and
glaucoma. Poor response to filtering procedures had

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Glaucoma

a connector tube of the plate with the anterior chamber. Figure 1: Ahmed Glaucoma Valve: Components
The receptacle plate posses a bivalved valvular system that
functions on Ventury flow principle. The first generation access to the aqueous flow from anterior chamber upto
Ahmed valve basically had three components made up of inner silicone membrane, which in turn regulates the
different materials. aqueous flow as per pressure equilibrium.
The receptacle plate was made of polypropylene where as The silicone membrane
the communicating tube was made out of silicone of 0.635 The silicone membrane has a unique feature of
mm external diameter and an inner diameter of 0.317 mm. unidirectional pressure regulating system based on the
The third component was the silicone membrane acting as tension on the membrane achieved is adequate pressure by
unidirectional valvular device attached with silicone tube virtue of a cover shield made of silicone or polypropylene.
so as to maintain aqueous communication from anterior Hence the membrane acts as unidirectional bivalved valve.
chamber. Cover shield
However polypropylene devices had witnessed significant The cover shields as mentioned earlier, is an essential
fibrosis around valve plate resulting in gradual reduction of feature of pressure regulating unidirectional bivalved
functional capability of the valve in due course of time. The valve system. This cover or shield is made of silicone or
present generation of Ahmed drainage device is essentially polypropylene depending upon the types of valve.
made of silicone including receptacle plate that has shown
excellent outcome. The research is still going on to improve
the valve functions, better control of aqueous flow as well
as biocompatibility to minimize fibrosis and other allogenic
tissue reactions.
Principle and components of AG Valve
AG Valve is consists of four essential components (Figure 1)
(i). The receptacle plate made of silicone / polypropylene

(13 x 16 mm) and having surface area of 184 mm2.
(ii). The communicating tube made out of silicone (external

diameter 0.635 mm and an inner diameter of 0.317
mm)
(iii). The silicone membrane:-
(iv). Cover shield:-
The receptacle plate
The receptacle plate measures 13 x 16 mm and has a
surface area of 184 mm2. The plate is made of silicon /
polypropylene and has two linear supports in the form of
a bar, and four posts that are sealed through the tension
cover and are responsible for the quality of the tension of
the membrane and the valves. Besides, such plate has on
its edge the tube in the proximal portion and, in each side
of it, two small out bounds perforated in the center that
constitute the fixation element of the device to the sclera,
since it is through this with which the valve will be sutured
to the sclera passes.
The communicating tube
The communicating tube is made up of silicone and having
external diameter of 0.635 mm and an inner diameter of
0.317 mm in all the models and sizes including in smaller
or paediatric valve. This silicone tube has direct attachment
with the middle of inner silicone membrane through a
perforation in it. The communicating tube provides direct

26 l DOS Times - Vol. 20, No. 1 July, 2014

(2) (a) Glaucoma
(b)

Figure 2: Ahmed Glaucoma Valve (FP 7) for adult or Normal size eye. Figure 3(a): Ahmed Glaucoma Valve (FP 7) for adult
or Normal size eye (Outer Surface), (b): Ahmed Glaucoma Valve (FP 7) for adult or Normal size eye (Inner Surface)

This cover is responsible to attain a desired level of the guideline and on the basis of expected good functional
tension in the silicone membrane so as to have valve outcome, preference may be drawn as per under mentioned
function. The cover provides support to the receptacle order.
plate. • All cases of refractory glaucoma with coexisting cataract.
Mechanism of pressure regulating action of the Glaucoma
Drainage Device (Cases those are non responsive to the glaucoma
The Ahmed Glaucoma valve acts on physics of “Ventury- surgery in the form of progressive glaucomatous
flow” system which is based on Bernoulli’s equation. changes irrespective of IOP status).
All modern GDD have the same basic design that consists • Cataract with Neovascular or Uveitic glaucoma.
of a silicone tube leading to a plate or a disc or an encircling • IOP of more than 21 mm of Hg despite filtering surgery
element posteriorly beneath the conjunctiva or the tenon’s and more than three drug regimen.
capsule. The plate or the discs placed posteriorly have a • All elderly cases of more than 60 years of age having
large surface area, which promote formation of a filtering mild to moderate cataract along with poor glaucoma
bleb posterior to the equator. Immediately following control.
implantation of any such device, there is a granulomatous • Elderly patients having uncontrolled IOP despite
reaction, which gradually resolves over a period of 4 to three drug regimen or Laser iridotomy with or without
5 months. The fibrous capsule matures over 6 months significant cataract.
making the bleb thinner. Histologically, the bleb develops • Moderate glaucoma with cataract having existing IOP
microcystic spaces, which serve as channels to shunt the of 21mm Hg or less but had initial uncontrolled IOP of
aqueous into orbital tissues. The control of IOP depends more than 27 mm of Hg.
upon the morphology of the filtering bleb. It is this fibrous • Glaucoma with coexisting cataract despite controlled
capsule which offers resistance to aqueous outflow. IOP but had initial uncontrolled IOP of more than 30
Disruption of conjunctival bleb leads to hypotony. mm of Hg.
Specifications of Ahmed Glaucoma drainage devices • All cases of congenital or juvenile glaucoma and
Glaucoma drainage devices are available in various designs cataract.
basically to meet with the need of adult as well as of • Traumatic subluxated cataract with angle recession
paediatric cases or of smaller eyeball. Two most common glaucoma.
designs and their specifications are as follows:- Relative contraindications
FP 7 (Newer generation AG Valve) for adult eye (Figure 2, (i). Eyes with severe scleral and/or corneoscleral limbus
3a,3b) thinning which may adversely influence proper fixation
Patient selection of the implant, or produces an unstable situation of the
Most of the cases of coexisting cataract and glaucoma may tube inside the anterior chamber due to poor resistance
be considered suitable for combined Phacoemulsification at the limbus.
and Glaucoma valve implantation. However as a general

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Glaucoma

Figure 4: The quadrant selection for placement of surgery so as to accord surgical ease and ultimate is better
Glaucoma valve performance.
The initial steps just short of tube insertion into anterior
(ii). Excessive conjunctival scarring or scleral thinning chamber through sclerostomy are being performed prior to
due to previous surgery or trauma where dissection the commencement of Cataract surgery. The cataract removal
of conjunctival flap may not be suitable. However is performed in a usual manner of Phacoemulsification by
such cases or cases of previous vitreo-retinal surgery clear corneal incision and direct chop technique except in
or multiple previous filtering procedures may be case of soft lens in Paediatric cases where Phacoaspiration
considered for glaucoma valve implant with scleral by Irrigation–Aspiration (I/A) either co axial or bimanual
or pericardium graft along with amniotic membrane/ method is an ideal choice. Author prefers to implant single
conjunctival grafting. Cases with existing retinal piece hydrophobic acrylic foldable IOL implant in most of
explants may be considered for valve implant. the cases. However any other kind of IOL can be used.
Anaesthesia
(iii). Ciliary block glaucoma. The choice of anaesthesia between general and peribulbar
(iv). Cataract and Glaucoma with intraocular silicone oil anaesthesia is based on the age of the patients. General
anaesthesia is essential in paediatric cases where as
due to vitreo-retinal surgery. Silicone oil may travel peribulbar anaesthesia is most suitable for adult cases .In our
into subconjunctival space through tube. However view, topical anaesthesia is not an ideal choice for drainage
valve implant may be considered in the inferior- device implant or for combined glaucoma and cataract
temporal quadrant in selected cases so as to allow the surgery due to obvious reasons of comparatively prolonged
tube position far away from the silicone, which has a duration of surgery and relatively more manipulations over
lower density than the aqueous humor. conjunctiva and sclera to place valve over it.
Phaco and AGV surgical technique The quadrant selection for placement of Glaucoma valve
The surgical technique of combined Ahmed glaucoma The implant can be put in any quadrant of the eyeball but
valve implantation and phacoemulsification cataract should be ascertain preoperatively (Figure 4). However the
surgery needs to be modified and various steps have to most prefered quadrant remains superior temporal quadrant
be performed in different sequences as compared to the due to following reasons( Figure 5a,5b,5c).
traditional isolated Valve implant or phacoemulsification • Placement of valve is smooth and easy.
• Relatively safer as superior temporal quadrant has

adequate space between valve and muscular structures,
hence subsequent fibrosis around valve plate is unlikely
to affect ocular motility.
Valve can be implanted in other quadrants also which in
the order of preference are

(a) (b) (c)

Figure 5(a): Valve implant in the superiortemporal quadrant and its relation with the post equator structures.
(b): Valve implant in the superiortemporal quadrant and its relation with the post equator structures.
(c): Valve implant in the superiortemporal quadrant and its relation with the Optic Nerve

28 l DOS Times - Vol. 20, No. 1 July, 2014

Glaucoma
(a) (b) (c)

Figure 6(a): Conjunctival flap. (b): Conjunctival flap
(c): Creation of subconjunctival pocket for the insertion of AG Valve plate

(a) (b)

Figure 7(a): Priming of the Valve: Insertion of fine cannula the tube.
(b): Priming of the Valve : Free flow of BSS through valve.

Ø Infero temporal by 90 degree peritomy. Subconjunctival infiltration of
Ø Superior-nasal and a small quantity of 2% lignocaine hydrochloride into
Ø Infero nasal. subconjunctival space prior to conjunctival and tenons
Caution: The optic nerve is relatively closer to the limbus dissection is preferred so as to facilitates adequate
in nasal quadrant due to the shorter distance in the nasal separation of flap. Bipolar cautery is suitably applied to
side between the globe and the optic nerve. Hence while make a good scleral bed for glaucoma drainage device
placing the implant in the nasal quadrants the valve should implantation (Figure 6c). Wire vectis is being used to
be fixed to the episclera at a maximal distance of 6 to 8 create an adequate subconjunctival pocket so as to
mm from the limbus so as to avoid any injury or proximity accommodate valve plate in a proper position.
to the optic nerve. Needless to emphasize the significance The priming of valve
of intraoperative evaluation of conjunctiva, sclera, limbus The priming of valve is an essential procedure prior to the
and iris prior to the final consideration of the entrance site. placement of the valve. A small quantity of Balanced salt
• Insertion of Superior rectus suture solution is pushed into silicon tube of AG valve with the help
Contrary to the conventional clear corneal Phaco surgery, of 27 gauze cannula mounted on 2 ml syringe so as to open
combined procedure demands superior rectus bridle suture up the valve and ensure its initial and definitive unsealing
as an essentiality. and patency of the silicone valves . Inadequate opening of
• Conjunctival flap Conjunctival dissection (Figure valve at this stage may lead to insufficient reduction in the
IOP during immediate postoperative period as well as the
6a,6b) should include the quadrant where the valve failure of valve functioning.
is going to be placed. After the insertion of Superior The tip of the cannula is introduced 3 to 4 mm into the
rectus suture, fornix based conjunctival flap is raised tube since the pressure required to prime the tube is over

www. dosonline.org l 29

Glaucoma (b) (c)
(a)

Figure 8 (a): Anchoring of the AG valve with the help of 7–O Prolene monofilament polyamide suture.
(b): Anchoring of the AG valve with the help of 7–O Prolene monofilament polyamide suture.

(c): Preplaced anchoring of the AG valve with the help of 7–o Prolene monofilament polyamide suture.

75 to 110 mm Hg. One should ensure adequate holding Figure 9: Securing AG Valve over Sclera
of the valve at this stage to avoid implant pushing away. It
is suggested, therefore, that the body of the valve be held and above parallel sutures ensure desired position of the
with the other hand while the priming is performed Figure valve over sclera since parallel sutures are unlikely to move
7a). While pushing fluid into the valve, the initial spurt of along with the movements of the eye ball.
fluid is observed (Figure 7b). Construction of partial thickness scleral flap
The simultaneous decrease in the resistance of the implant A small limbal based partial thickness scleral flap of about
to the outflow of the liquid is felt immediately. In certain 4.5 mm square was fashioned to cover the silicone tube of
cases, priming may need more pressure to attain free and AG valve prior to its insertion into anterior chamber (Figure
smooth flow probably owing to the some variation in the 10).
assembly of the valve. However, author did not encounter Advantages of partial thickness scleral flap and Sclerostomy
such problem in his personal experience in a large series over patch graft /Amniotic membrane /pericardium graft
of several cases. • Partial thickness scleral flap and sub scleral sclerostomy
Anchoring of the AG valve
Preplaced anchoring: The AG valve can be anchored with technique is a safe procedure that offers some
the help of 7–o Prolene / 8–O monofilament polyamide advantages over the conventional graft implantation
suture. Author prefers to apply 7–o Prolene suture since it technique.
provides better grip to the valve over sclera. • Technically much simpler & easy.
Brigadier Parihar’s Modified technique of AG Valve placement
In this technique, author prefers to use without lock straight
needle holder with reverse movements both at the time of
preplaced anchoring of valve as well as while securing
valve over sclera. Such reverse movement with straight
needle holder facilitates smooth insertion of suture.
7‘O Monofilament Poly Propylene suture on 3/8 circle
tapered needle is passed through both the eyelets of valve
plate and tied over plate by double knots (Figure 8a,8b,8c).
Subsequently AG Valve is placed over sclera by reverse
suturing into the sub-tenon space approximately 6 to 8 mm
away from the limbus (Figure 9).
It is recommended to place scleral sutures by revere pattern
and parallel to the limbus, rather than perpendicular for
obvious reasons of surgical comforts and ease. Such sutures
can be tied over sclera without much discomforts. Over

30 l DOS Times - Vol. 20, No. 1 July, 2014

Glaucoma
(12) (13)

Figure 10: Construction of partial thickness scleral flap. Figure 12: Capsulorhexis
Figure 13: Main incision for insertion of Phaco tip
(a) (b)
manner. Author prefers to apply direct Phaco chop
Figure 11(a): Clear corneal incision temporal to the scleral flap. technique through clear corneal incision in adult cases
(b): Side port clear corneal incision just adjacent to the scleral flap. where as Phaco aspiration by coaxial /bimanual technique
in soft or in paediatric cases. Single piece hydrophobic
• No need of extra instrumentation, least expensive. acrylic foldable IOL implant is an ideal choice. However
• No need to procure preserved scleral or pericardium other types of foldable IOL implants can also be used.
• Site of clear corneal incision: Site of clear corneal
graft or amniotic membrane, hence less expensive.
• Partial thickness scleral flap doesn’t produce any incision is chosen according to the probable site of
tube entry in to the AC as well as on the surgical ease
immunological reaction as possible with allograft or while performing Phaco with sutured AG valve plate
other materials. over sclera. Author prefers to construct two identical
• Minimal inflammatory reaction, better control of IOP. incisions each of one mm size with the help of 15
• Easy to cover scleral flap by conjunctiva as compare degree entry blades. Of these, one incision is being
to the allograft hence less foreign body sensation and converted into 2.8 mm main incision after completion
better tolerance and less chances of tube extrusion or of rhexis and hydro procedures. The chosen site
exposure. remains distal temporal for right eye (Figure 11a,11b)
Relative Indications of patch graft/Amniotic membrane/ and nasal for left eye respectively provided valve is
pericardium graft over partial thickness scleral flap being placed in the temporal quadrant. However site
Partial thickness scleral flap may not be suitable in cases of incision will require modification according to the
of extensive conjunctival scarring such as in cases of position of valve in different quadrant.
chronic recurrent uveitis, rheumatoid arthritis, complicated • Capsulorhexis: Most of cases of coexisting Cataract
glaucoma associated with scleral thinning like chemical and Glaucoma are invariably associated with rigid and
injuries and post traumatic complicated glaucoma. miotic pupil and hard cataract or both simultaneously.
The remaining steps of valve implantation like shortening Miotic pupil may require mechanical stretching of the
and entry of tube into the anterior chamber were performed pupil with the help of iris hooks. In certain cases dye
after completion of phacoemulsification surgery and will enhanced rhexis may be necessary and beneficial.
be described subsequently in detail. However rhexis can be completed without much
Phacoemulsification surgery inconvenience (Figure 12).
After the completion of placement of AG Valve over sclera • Hydro procedures and nucleus rotation: Hydro
and construction of partial thickness scleral flap, the steps procedures are very crucial requirement of successful
of phacoemulsification surgery are performed in a standard phaco and energy modulation. Gentle, meticulous and
repeated efforts are essential to achieve complete and
good hydrodissection and delineation.
The nucleus rotation demands utmost care since cataract
associated with glaucoma are invariably associated to
have intercapsular adhesions between cortical plate
and the fornices of the capsular bag. Forceful rotation in
this situation may lead to intraoperative complications
like zonulysis, posterior capsular rent or even nucleus
dislocation into the vitreous cavity.

www. dosonline.org l 31

Glaucoma (b) (c)
(a)

Figure 14 (a): Nucleotomy by direct chop technique.
Figure 14 (b): Nucleotomy by direct chop technique. Figure 14 (c): Fragment aspiration.

(a) (b) (c)

Figure 15(a): Management of residual cortical plate. (b): Management of residual cortical plate.
(c): Coaxial I/A removal of residual cortical plate.

Main incision for insertion of Phaco tip: After completion Management of residual cortical plate
of hydro procedures and nucleus rotation, the temporal Management of residual cortical plate can be done in three
incision is being extended with the help of 2.8 mm stages
keratome so as to facilitates entry of phaco tip into the • Meticulous and adequate attention on hydroprocedure
anterior chamber (Figure 13).
Nucleotomy: Nucleotomy can be performed by any lead to sufficient softening of cortical matter. While
method. Author prefers to perform direct central chopping performing nucleotomy a repeated and gentle irrigation
(Figure 14a,b,c) in most of the cases. Peripheral chopping is very important to have smooth completion of I/A
may find difficulty in cases of miotic pupil or very hard procedures.
and large nucleus. Sculpting also find difficulty in most of Author continues to remove a significant chunk of
the time due to complicated nature of the cataract which is cortex with the help of Zero degree phacotip. However
invariably associated with other pathologies like thinning it is better to use I/A mode if any other type of phacotip
of posterior capsule, zonular weakness and vitreous is being used (Figure 15a,b,c).
degeneration, hence likely to have higher incidence of • Use of Capsule polisher:- Use of Capsule polisher to
intraoperative complications. Chopping is relatively safe dislodge cortical plate from periphery is very useful
as compared to other methods of nucleotomy since there and highly recommended.
is no pressure on zonules and vitreous while performing • Final removal of residual cortical matter can be done
nucleotomy. As such chopping requires less energy as either by Coaxial or Bimanual irrigation/Aspiration
compare to the sculpting to complete the phacoprocedures. cannula.
In our practice, we are using moderate settings of aspiration, A high vacuum and adequate flow rate is recommended for
flow and phacopower (Ranging from 10 to 30% on white this purpose.
staar technology).

32 l DOS Times - Vol. 20, No. 1 July, 2014

(a) (b) (c) Glaucoma
(d)

Figure 16(a): Single piece hydrophobic IOL implant is being implanted. (b): Single piece hydrophobic IOL implant is being implanted.
(c): Single piece hydrophobic IOL implant is in situ. (d): Single piece hydrophobic IOL implant is in situ.

Figure 17: Preparation of tube: The tube is being shorten to zone of visual axis and should exactly traverse through
achieve approximately 2-2.5 mm length in the anterior chamber trabecular meshwork. However it is not possible to attain
all the ideal situation in each and every case.
IOL Implantation Preparation of tube and insertion technique
IOL Implantation technique essentially remains same The tube should be made shorter in such a manner so as
as in conventional phacoemulsification surgery. Any to achieve approximately 2-2.5 mm length in the anterior
kind of foldable IOL can be implanted. However in our chamber (Figure 17). The distal tip of the tube should be
view, single piece hydrophobic IOL implant is most cut in such a manner so as to attain elongated bevel down
safe and acceptable to the eye, particularly in all type of position. Such position has surgical ease while inserting
complicated cases including coexisting Glaucoma and into AC as well as facilitates least trauma to the corneal
Cataract and undergoing highly complex procedures like endothelium as well as adequate patency of the tube even
GDD implantation. These IOL implants are known to have in the event of iris touch.
least inflammation, posterior capsular opacification as well How to construct Sclerostomy/Scleral tunnel for valve tube
as zero incidence of opacification of IOL implant even in insertion
cases of concurrent AG Valve and Phaco surgery and other The scleral tunnel or sclerostomy under partial thickness
complex situations (Figure 16a-16d). scleral flap can be performed prior to the commencement
Insertion of Valve drainage tube in to the Anterior Chamber or after the completion of phaco procedure. However in
After completion of phacoemulsification the next step is to our view, it is most appropriate to design sclerostomy after
prepare drainage tube for insertion into anterior chamber. completion of phaco and just before the insertion of tube
Ideal length of the tube in the Anterior Chamber into the anterior chamber (AC).
The ideal length of silicone drainage tube into AC is mainly Needle or Blade: Author has experimented and evaluated
based on the depth of the anterior chamber and other various methods of construction of scleral tunnel or
configurations those are likely to vary on the merits of each sclerostomy for the insertion of silicon tube into AC.
and every case. However an ideal length is around two to However most safe mode remains use of 22 gauze needle
three mm in the anterior chamber. which is bent upto 45 to 60 degree angle and just short of
Essential criteria of adequate length: In general the ideal hub of the needle. It is very difficult to manipulate tube
position of drainage tube is one where it should not touch insertion through the sclerostomy created with the help of
any structure in the anterior chamber including posterior 23 gauze needle. The side port entry blade can also be
surface of cornea, iris or lens. It should not come in the used for this purpose, however one may not be sure about
exact width of the tunnel as well as of subsequent stability
of the tunnel which may be too loose and resulting leaking
tunnel in turn. The most suitable alternative to needle is
0.9 mm Keratome which is being used in Micro phaco
(Phaconit/ MICS) procedures. Author found to have an
excellent wound construction and stable tunnel created
with the help of MICS Keratome.
Sclerostomy without partial thickness scleral flap
Sclerostomy can be fashioned without creating scleral flap.
Direct insertion of 22 gauze needle or MICS blade under

www. dosonline.org l 33

Glaucoma

Figure 18: 22 Gauze needle track sub scleral flap Sclerostomy
Figure 19: Insertion of Silicon tube into Anterior Chamber

meticulous observation and to ensure parallel movement of Figure 20: Suturing of Partial thickness scleral flap
the tip of needle or blade at subscleral plane may achieve
desired results. Management of residual viscoelastic material
The direction of the needle Viscoelastic material used during the phacoemulsification
The direction that needle should traverse while penetrating cataract surgery can be left in the anterior chamber after
the anterior chamber it should be parallel to the plane of the completion of surgery since it will pass through the tube of
iris (Figure 18). The most ideal situation remains through the valve during the first hours after surgery. Viscoelastic
angle of anterior chamber; however the final location of material in the anterior chamber minimizes the risk of
track will invariably vary in case to case basis despite an excessive hypotony and shallow chamber during immediate
identical approach in all cases. Construction of sclerostomy postoperative period as well as reduces the incidence of
track in cases of angle closure glaucoma is very tricky and choroidal detachment.
demands utmost accuracy and attention due to less space Postoperative treatment and follow-up regimen
available in anterior chamber. However Myopia and At the end of surgery the administration of a subconjunctival
juvenile glaucoma don’t pose much inconvenience while injection comprises of 15 mg gentamycin and 4 mg of
constructing track but scleral thinness must be kept in mind subconjunctival dexamethasone along with small quantity
to avoid inadvertent perforation. However it is better to of lignocaine is recommended.
keep tube away from cornea upto maximum possibility. Topical Dexamethasone and Neomycin 0.3% eye drops
Insertion of Silicon tube into Anterior Chamber are given four times daily for 4 weeks and three times in
Silicon tube can be inserted into anterior chamber with the a day for subsequent two weeks. Moderate cycloplegics
help any forceps. Dr. Mateen Ahmed has specially designed like cyclopentolate is recommended twice in a day for one
grooved and curved forceps which facilitates smooth week followed by once in a day for subsequent one week.
insertion of the tube into anterior chamber. However
McPherson forceps can also be used for this purpose.
The silicone tube of the AG Valve drainage device is
allowed to make entry into the AC through sclerostomy
created with the help of a 22 gauge syringe needle. The
tube entry is ensured to remain parallel to the iris plane
throughout its course and at its final position (Figure 19).
Suturing of Partial thickness scleral flap: After insertion of
silicon tube into the anterior chamber, partial thickness
scleral flap is repositioned and may be sutured with the
help of 10 “0” monofilament suture. Author prefers to place
two horizontal sutures on either side of the tube as well as
two additional sutures horizontally at the end of the flap
(Figure 20).
The conjunctiva can be secured with 8-0/10-0 monofilament
nylon / Vicryl suture.

34 l DOS Times - Vol. 20, No. 1 July, 2014

Glaucoma

No antiglaucoma medication is required during initial Postoperative complications
phase of hypotony. Though combined AG Valve implantation and
Detailed and meticulous postoperative examination is Phacoemulsification surgery don’t face much intraoperative
essential and very crucial and should be carried out in problems as well as the pattern and incidence of
all cases at regular interval during follow-up period. The postoperative complications do not exceed that to of singular
emphasis should be given on assessment of visual acuity, phacoemulsification or glaucoma valve implant surgery.
extra ocular movements, and IOP measurement using non As such in last one decades both phacoemulsification and
contact tonometer method. Detailed slit lamp, fundus Glaucoma Valve surgery has witnessed marked decline
and other examinations should be carried out on day 1,3 in the incidence and pattern of complications both in
followed by one week interval for four weeks and monthly quantum and severity.
thereafter for six month and periodically thereafter as and Postoperative complications can be grouped into
when indicated. In cases of non cooperative or very young immediate and early, intermediate and delayed post
children, examination under GA should be carried out operative complications.
at monthly interval for initial period of three months and Immediate and early post operative complications
thereafter if indicated. The main constraint in GDD implant remains undue
In terms of IOP, a complete success has been defined hypotony both in immediate as well as during intermediate
as IOP of between 9 to 21 mm Hg without medication, post operative period. Other noted but infrequent post
qualified success as IOP between 14 to 21 mm Hg with one operative complications are as follows :-
or more medication, and failure as a sustained secondary • Hyphaema (Secondary) : 1%
rise of (Once stabilized to an optimal satisfactory level) post • Choroidal detachment : 3- 5%
op IOP of >21 mm Hg with one or more medications for • Shallow chamber with hypotony : 5-7 %
more than one months. Complete failure can be defined as • CME : 3 -5%
chronic hypotony (Hypotony is defined as IOP less than 6 • Corneal endothelial touch of drainage tube :2 - 3 %
mm Hg on any single visit.), need of additional glaucoma • Irido drainage tube adhesions : 1 -2 %
surgery, development of phthisis bulbi or loss of light • Iridocorneal synaechiae : 2 -3 %
perception attributed to glaucoma. • Encapsulated bleb : 9 -10 %
It is very important to observe closely the immediate • Partial exposure of valve plate : 0.5 to 0.75 %
postoperative period, since the functional future of the
valve could depend of such follow-up. Post operative status of IOP
Frequent evaluation of the anterior chamber’s depth should Concurrent Phacoemulsification with AG Valve
be done during the first 5 to 10 days, period in which implantation has shown remarkable control of IOP even in
formation of the cyst that will wrap the body of the valve in long term follow up in cases of refractory glaucoma despite
the future is initiated. One should make sure that the depth three or more drug regimen. In our experience, more than
of the anterior chamber is maintained more or less constant 90% cases continue to maintain complete success (IOP of
or increases as days go by. between 9 to 21 mm Hg without medication) following
Concurrent Phacoemulsification and AG Valve implantation more than four years follow up where as Qualified IOP
surgery is technically a sound and viable procedure. The control (IOP between 14 to 21 mm Hg with one or more
incidence and pattern of intraoperative complications medication) was seen in remaining cases .We did not
don’t magnify both in terms of quantum and pattern as notice any failure so far.
compared to singular Phacoemulsification or AG Valve Conclusion
implantation alone. We did not notice any significant The AGV implant has the advantage of achieving a lower
intraoperative complications except difficulty in inserting rate of over drainage without having to perform a two
AG Valve tube into AC in first attempt in less than 4% and staged operation or to modify the surgical technique.
trace of hyphaema in two percent cases in the experience In our view the GDD device valve has been found to be
of more than 200 cases in last five years. These problems very effective in the management of refractory glaucoma in
were mainly observed in cases of cataract associated cases of coexisting Glaucoma and Cataract irrespective of
with angle closure or Neovascular Glaucoma especially age and aetiology which provides good visual rehabilitation
during initial phase of learning curve. The incidence of and control of IOP, with low incidence of complications.
such complications can be restricted further upto the bare
minimum by introduction of viscoelastic materials into the
anterior chamber through separate paracentesis just prior
to the insertion of silicone tube into the anterior chamber.

www. dosonline.org l 35

Glaucoma

References 21. Morod Y, Donaldson C, Kim Y, Abdolell M, et al. The ahmed
drainage implant in the treatment of pediatric glaucoma, Am. J.
1. Rosenberg LF, Krupin T. Implants in glaucoma surgery: In: Ritch R, Ophthalmol. 2003;135:821-9.
Shields MB, Krupin T, editors: The Glaucomas, 2nd ed. St. Louis:
Mosby, 1996:1783–1807. 22. Hamush NG, Coleman AL, Wilson MR. Ahmed glaucoma valve
implant for management of glaucoma in Sturge-Weber syndrome.
2. Alejandro N. Chung, Tin Aung, Jenn C. Wang, et al. Surgical outcomes Am J. Ophthalmol. 1999;128:758-60.
of Combined Phacoemulsification and Glaucoma Drainage Implant
Surgery for Asian Patients With Refractory Glaucoma with Cataract: 23. Al-Aswad LA, Netland PA, Bellows AR, Ajdelsztajn T, et al. Clinical
Am J. Ophthalmol. 2004;137:294–300. experience with the double-plate Ahmed glaucoma valve. Am J.
Ophthalmol. 2006;141:390-1.
3. Miller SJH. Genetic aspects of glaucoma. Trans Ophthalmol. Soc UK
1966; 86:425-434. 24. Taglia DP, Perkins TW, Gangnon R, Heatley GA, et al. Comparison
of the Ahmed glaucoma valve, the Krupin eye valve with disk, and
4. Broadway D, Grierson I, Hitchings R. Racial differences in the the double plate Molteno implant. J. Glaucoma 2002;11:347–53.
results of glaucoma filtration surgery: are racial differences in the
conjunctival cell profile important? Br. J. Ophthalmol. 1994;78:466– 25. Tsai JC, Johnson CC, Kammer JA, Dietrich MS. The Ahmed shunt
7. versus the Baerveldt shunt for refractory glaucoma II: longer-term
outcomes from a single surgeon. Ophthalmology. 2006;113:913-7.
5. Aung T, Seah SKL. Glaucoma drainage implants in Asian eyes.
Ophthalmol. 1998;105:2117–22. 26. Wilson MR, Mendis U, Paliwal A, Haynatzka V. Long-term follow-up
of primary glaucoma surgery with Ahmed glaucoma valve implant
6. Da Mata A, Burk SE, Netland PA, Baltatzis S, et al. Management versus trabeculectomy. Am J. Ophthalmol. 2003;136:464-70.
of uveitic glaucoma with Ahmed glaucoma valve implantation.
Ophthalmol. 1999;106:2168-72. 27. Wilson MR, Mendis U, Smith SD, Paliwal A. Ahmed glaucoma valve
implant vs. trabeculectomy in the surgical treatment of glaucoma: a
7. Ishida K, Netland PA. Ahmed Glaucoma Valve implantation randomized clinical trial. Am. J. Ophthalmol. 2000;130:267-73.
in African American and white patients. Arch Ophthalmol.
2006;124:800-6. 28. Papadaki TG, Zacharopoulos IP, Pasquale LR, Christen WB, et al.
Long-term results of Ahmed glaucoma valve implantation for uveitic
8. Watson JC, Kadri OA, Wilcox MJ. Effects of mitomycin C on glaucoma. Am J Ophthalmol. 2007;144:62-9.
glaucoma filtration capsules. Biomed Sci. Instrum. 2005;41:394-9.
29. Melamed S, Fiore PM. Molteno implant surgery in refractory
9. Kurnaz E, Kubaloglu A, Yilmaz Y, Koytak A, et al. The effect of glaucoma. Surv. Ophthalmol. 1990;34:441–8.
adjunctive Mitomycin C in Ahmed glaucoma valve implantation.
Eur. J. Ophthalmol. 2005;15:27-31. 30. Jewelewicz DA, Rosenfeld SI, Litinsky SM. Epithelial downgrowth
following insertion of an ahmed glaucoma implant. Arch
10. Sarodia U, Sharkawi E, Hau S, Barton K. Visualization of aqueous Ophthalmol. 2003;121:285-6.
shunt position and patency using anterior segment optical coherence
tomography. Am J. Ophthalmol. 2007;143:1054-6. 31. Trigler L, Proia AD, Freedman SF. Fibrovascular in growth as a cause
of Ahmed glaucoma valve failure in children. Am J. Ophthalmol.
11. Carrillo MM, Trope GE, Pavlin C, Buys YM. Use of ultrasound 2006;141:388-9.
biomicroscopy to diagnose Ahmed valve obstruction by iris. Can J.
Ophthalmol. 2005;40:499-501. 32. Merrill KD, Suhr AW, Lim MC. Long-term success in the correction
of exposed glaucoma drainage tubes with a tube extender. Am J.
12. Budenz DL, Pyfer M, Singh K, Gordon J, et al. Comparison of Ophthalmol. 2007;144:136-7.
phacotrabeculectomy with 5-fluorouracil, mitomycin-C, and without
antifibrotic agents. Ophthalmic Surg. Lasers 1999;30:367–74. 33. Feldman RM, El-Harazi SM, Villanueva G. Valve membrane
adhesion as a cause of Ahmed glaucoma valve failure. J. Glaucoma
13. Donoso R, Rodriguez A. Combined versus sequential 1997;6:10–12.
phacotrabeculectomy with intraoperative 5-fluorouracil. J. Cataract
Refract. Surg. 2000;26:71-4. 34. Lam DSC, Lai JSM, Chua JKH, et al. Needling revision of glaucoma
drainage device filtering blebs. Ophthalmol. 1998;105:1127.
14. Hoffman KB, Feldman RM, Budenz DL, Gedde SJ, et al. Combined
cataract extraction and Baerveldt glaucoma drainage implant: 35. Eibschitz-Tsimhoni M, Schertzer RM, Musch DC, Moroi SE.
Indication and outcomes. Ophthalmol. 2002;109:1916-20 Incidence and management of encapsulated cysts following Ahmed
glaucoma valve insertion. J. Glaucoma 2005;14:276-9.
15. Wedrich A, Menapace R, Radax U, Papanos P. Long-term results
of trabeculectomy and small incision cataract surgery. J. Cataract 36. Tannenbaum DP, Hoffman D, Greaney MJ, Caprioli J. Outcomes
Refract Surg. 1995;21:49–53. of bleb excision and conjunctival advancement for leaking or
hypotonous eyes after glaucoma filtering surgery. Br. J. Ophthalmol.
16. Derick RJ, Evans J, Baker ND. Combined phacoemulsification and 2004;88:99-103.
trabeculectomy versus trabeculectomy alone: A comparison study
using mitomycin-C. Ophthalmic Surg. Lasers 1998;29:707–13. 37. Christmann LM, Wilson ME. Motility disturbances after Molteno
implants. J. Pediatr. Ophthalmol. Strabismus 1992; 29:44–8.
17. Donoso R, Rodriguez A. Combined versus sequential
phacotrabeculectomy with intraoperative 5-fluorouracil. J. Cataract 38. Wentzloff JN, Grosskreutz CL, Pasquale LR, Walton DS, et al.
Refract. Surg. 2000;26:71–4. Endophthalmitis after glaucoma drainage implant surgery. Int
Ophthalmol. Clin. 2007 Spring; 47:109-15.
18. Filous A, Brunova B. Results of the modified trabeculotomy in the
treatment of primary congenital glaucoma. J. Aapos. 2002; 6:182-6 39. Bayraktar Z, Kapran Z, Bayraktar S, Acar N, et al. Delayed-onset
streptococcus pyogenes endophthalmitis following Ahmed
19. Hill R, Heur D, Baerveldt G, Minckler D, et al. Molteno implantation glaucoma valve implantation. Jpn. J. Ophthalmol. 2005;49:315-7.
for glaucoma in young patients. Ophthalmol. 1991;98:1042-6.
40. Gutierrez-Diaz E, Montero-Rodriguez M, Mencia-Gutierrez
20. Englert J, Freedman S, Cox T. The Ahmed Valve in Refractory E, Fernandez-Gonzalez MC, et al. Propionibacterium acnes
Pediatric Glaucoma. Am. J. Ophthalmol.1999;127:34-42.

36 l DOS Times - Vol. 20, No. 1 July, 2014

Glaucoma

endophthalmitis in Ahmed glaucoma valve. Eur J Ophthalmol. 48. Al-Aswad LA, Netland PA, Bellows AR, Ajdelsztajn T, Wadhwani
2001;11:383-5. RA, Ataher G, Hill RA.Clinical experience with the double-plate
41. Gedde SJ, Scott IU, Tabandeh H, Luu KK, et al. Late endophthalmitis Ahmed glaucoma valve. Am J Ophthalmol. 2006;141:390-391.
associated with glaucoma drainage implants. Ophthalmology.
2001;108:1323-7. 49. Brasil MV, Rockwood EJ, Smith SD. Comparison of silicone and
42. Papadaki TG, Siganos CS, Zacharopoulos IP, Panteleontidis V, et al. polypropylene Ahmed Glaucoma Valve implants.J Glaucoma.
Human amniotic membrane transplantation for tube exposure after 2007;16:36-41.
glaucoma drainage device implantation. J Glaucoma. 2007;16:171-
2. 50. Ishida K, Netland PA, Costa VP, Shiroma L, Khan B, Ahmed
43. Ainsworth G, Rotchford A, Dua HS, King AJ. A novel use of amniotic II.Comparison of polypropylene and silicone Ahmed Glaucoma
membrane in the management of tube exposure following glaucoma Valves. Ophthalmology. 2006;113:1320-6.
tube shunt surgery.Br J. Ophthalmol. 2006;90:417-9.
44. Rai P, Lauande-Pimentel R, Barton K.Amniotic membrane as an 51. Nouri-Mahdavi K, Caprioli J. Evaluation of the hypertensive phase
adjunct to donor sclera in the repair of exposed glaucoma drainage after insertion of the Ahmed Glaucoma Valve. Am J Ophthalmol.
devices.Am J Ophthalmol. 2005;140:1148-52. 2003;136:1001-8.
45. Chan CH, Lai JS, Shen SY. Delayed retrobulbar haemorrhage after
Ahmed glaucoma implant: a case report. Eye. 2006;20:494-5. 52. Garcia-Feijoo J, Cuina-Sardina R, Mendez-Fernandez C, Castillo-
46. Tuli SS, WuDunn D, Ciulla TA, Cantor LB.Delayed suprachoroidal Gomez A, Garcia-Sanchez J. Peritubular filtration as cause of severe
hemorrhage after glaucoma filtration procedures.Ophthalmology. hypotony after Ahmed valve implantation for glaucoma. Am J.
2001;108:1808-11. Ophthalmol. 2001;132:571-2.
47. Kahook MY, Noecker RJ, Pantcheva MB, Schuman JS.Location
of glaucoma drainage devices relative to the optic nerve.Br J 53. Kee C. Prevention of early postoperative hypotony by partial ligation
Ophthalmol. 2006;90:1010-3. Epub 2006 Apr 13. of silicone tube in Ahmed glaucoma valve implantation. J Glaucoma.
2001;10:466-9.

Required

1. Phaco Eye Surgeon (Experienced)
2. Paediatric Ophthalmologist (Fellowship Trained)
3. Paediatric Optometrist (Preferably Fellowship Trained)
for 60 bedded Modern Eye Hospital (Tertiary Eye Care Centre) at Haridwar

Contact / Send C.V.

Ganga Mata Charitable Eye Hospital

Saptrishi Link Road, Haridwar - 249410 (U.K.)
Ph.: 01334-260190, Fax: 01334-260175, (M): 09412931046

Email: [email protected] w Website: www.gmeh.in

www. dosonline.org l 37

Circumferential Trabeculotomy Using an Il uminated GlaGulacuocomma
Microcatheter: A New Treatment for Primary Congenital Glaucoma
Tanuj Dada
MD

Tanuj Dada MD, Shreyas Temkar MBBS, Reetika Sharma MD, Dewang Angmo MD,
Shikha Gupta MD, Ramanjit Sihota MD

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

Primary congenital glaucoma (PCG) is the most common most commonly performed surgeries in the current day
type of primary pediatric glaucoma1. The condition is glaucoma practice.
typically bilateral (65 to 80%) and most of them manifest Although most surgeons across the country perform
during first year of life2. The incidence varies among combined trabeculectomy – trabeculotomy surgery
different ethnicities. In India the prevalence is estimated to combined with Mitomycin C, it has been our experience
be 1 in 3300 live births and accounts for 4.2% of overall that trabeculectomy hardly works in infants due to
childhood blindness3. excessive fibrosis and we rarely see a well formed bleb
The basic abnormality in PCG is isolated trabeculodysgenesis in these patients after trabeculectomy. Hence a well done
or goniodysgenesis - a developmental arrest with failure of trabeculotomy may be sufficient for children presenting
the uveal tissue to migrate posteriorly. This uveal tissue before 2 years of age without the need for adding
blocks the drainage of aqueous through the underlying trabeculectomy and exposing the eye to the toxic effects of
trabecular meshwork leading to a rise in intra ocular mitomycin C. In conventional trabeculotomy we only treat
pressure4-6. The primary aim of most glaucoma surgeries for 90-120 degrees of the angle and therefore we started this
PCG is to remove this blockade and create an adequately technique at our centre with the aim of performing a 360
draining pathway to the aqueous. degrees trabeculotomy.
Medical management is useful for temporary control of Principle of common glaucoma surgeries
IOP, to reduce corneal edema before surgery and post Goniotomy involves cleaving the angle under gonioscopic
operatively when surgery fails to control IOP completely. visualization to restore the outflow. However, it requires
Surgery is the definitive and effective form of treatment
in congenital glaucoma. The aim of surgical therapy is to Figure 1: Glaucolight-Illuminated fiberoptic
remove this obstruction, restoring the access of aqueous microcatheter
to Schlemm’s canal thus maintaining the physiological
outflow.
Various surgical options are available in the treatment
of PCG. They include angle surgeries like goniotomy,
trabeculotomy (manual, 3600 suture or microcatheter
assisted); filtration surgeries like trabeculectomy,
combined trabeculotomy with trabeculectomy with or
without anti-metabolites; glaucoma drainage devices,
and cyclodestructive procedures. Goniotomy, ab-
externo trabeculotomy, combined trabeculotomy with
trabeculectomy with or without mitomycin - C are the

www. dosonline.org l 39

Glaucoma

Figure 2: Creation of a superficial scleral flap Figure 3: Creation of a deep scleral flap

a clear cornea for proper visualization of angle structures. new technique of illuminated microcatheter assisted
Most of our patients present with corneal changes, also circumferential trabeculotomy has been advocated.
reported to be high (>80% ) in a study from our centre7. It involves the use of an illuminated microcatheter to
Therefore, goniotomy is often not a feasible option in our catheterize the whole circumference of the Schlemm’s
scenario. canal and 3600 trabeculotomy is performed. This flexible
The goal of trabeculotomy is to increase the outflow by microcatheter has a LED source at its atraumatic tip that
cleaving the site of greatest resistance i.e., the inner wall allows visualization of the catheter through the limbus
of schlemm’s canal and adjacent trabecular meshwork. transsclerally to verify proper placement. This greatly
Conventional ab – externo trabeculotomy involves the reduces the chances of inadvertent false passages. Currently
use of a rigid instrument (Harms trabeculotome) to tear two illuminated microcatheters are in use i.e., Glaucolight
through the trabecular meshwork for approximately 100 to (DORC- Dutch Ophthalmic Research Centre International,
120 degrees of the angle. Complications reported include The Netherlands) and the iTRACK 250A (iScience
hyphema, inadvertent filtering blebs, choroidal detachment, Interventional, Menlo Park, CA). These microcatheters were
iridodialysis, lens damage, creation of false passage into the initially introduced for performing canaloplasty, a surgical
anterior chamber or suprachoroidal space8,9. option in the treatment of primary open angle glaucoma
The technique of 360 degree trabeculotomy using suture in adults. Glaucolight microcatheter (used by us) is a light
material was first described by Smith in 1962 on cadaver fiber based device with an integrated (battery powered)
eyes10. The technique was refined by Beck and Lynch using LED source and an atraumatic tip-design for a smooth
6-0 polypropylene and reported a success rate of 87%11. transfer through the Schlemm’s canal. The bright LED
But the suture trabeculotomy is itself associated with illuminated fiber tip helps to visualize the position of the
many complications like difficulty in advancing the suture fiberoptic tip during 360 degree Schlemm’s canal passage.
through the whole circumference of Schlemm’s canal with It has a 40G/0, 150 micron diameter for minimally invasive
a single cut down, the need for gonioscopic verification surgery and flexibility for 360 degree catheterization of the
and the possibility of inadvertent false passages12-14. Schlemm’s canal.
Combined trabeculotomy- trabeculectomy with or without Illuminated microcatheter assisted circumferential
antimetabolites like mitomycin-C (MMC) is considered trabeculotomy - Technique
the standard therapy for treatment of PCG15,16,17. This The procedure is performed under general anesthesia.
procedure is reported to have higher long term success than Steps
either procedure separately17,18. Reported complications 1. A 5mm superonasal conjunctival peritomy is made
include those related to the filtering bleb and use of MMC
like excessive filtration, failure, leak and bleb related followed by creation of a superficial scleral flap of
infections19-22. 4.0mm x 4.0mm (Figure 2).
Principle of Illuminated microcatheter assisted 2. A deep scleral flap is made to identify and deroof the
circumferential trabeculotomy (IMCT) Schlemm’s canal (Figure 3).
To overcome the problems associated with rigid 3. The microcatheter is introduced into the Schlemm’s
instrumentation, bleb formation and mitomycin use, a canal (Figure 4) and advanced through the whole

40 l DOS Times - Vol. 20, No. 1 July, 2014

Glaucoma

Figure 4: Microcatheter introduced into Figure 5: Microcatheter advanced through the
Schlemm’s canal Schlemm’s canal (illuminated tip at 10’0 clock limbus)

Figure 6: Microcatheter advanced through the Figure 7: Microcatheter exit from the
Schlemm’s canal (illuminated tip at 3’0 clock limbus) opposite end of Schlemm’s canal

circumference (3600) of the Schlemm’s canal (Figure 5 Postoperative management
and 6). In the postoperative period, a topical cycloplegic is given
5. Paracentesis is performed to ensure low IOP before along with steroid – antibiotic combination in tapering
performing trabeculotomy. doses over 6-8 weeks.
6. If a successful complete 3600 catheterization is Intraoperative problems -What can go wrong and
achieved (Figure 7) the two ends of the catheter are how to manage?
pulled in opposite directions like a purse-string, Failure of complete catheterization can occur due to
breaking through the trabecular meshwork to perform misdirection of the microcatheter into a collector channel
a 3600 trabeculotomy (Figure 8). (Figure10), or obstruction within the Schlemm’s canal
7. The closure of the scleral flap is done with 10-0 MFN (Figure 11). In case of misdirection, slight manipulation
suture to ensure a water tight seal that would prevent of the microcatheter can be done to redirect it into the
formation of an inadvertent filtering bleb (Figure 9). Schlemm’s canal. In case of obstruction, the catheter
8. Peritomy is closed with 8-0 vicryl followed by can be passed from other side of Schlemm’s canal or
subconjunctival injection of antibiotic and steroid. conjunctiva at the site of obstruction can be incised and a

www. dosonline.org l 41

Glaucoma

Figure 8: Circumferential trabeculotomy performed Figure 9: Closure of scleral flaps
by pulling the catheter like a purse string

Figure 10: Microcatheter misdirection (dotted arrow Figure 11: Microcatheter
indicating misdirection into a collector channel) obstruction

scleral cut down is made over the tip of microcatheter, the Sarkisian23 conducted retrospective consecutive case
tip is grasped and an attempt is made to recannulate the series study in 16 eyes of 10 patients of PCG and found
canal. Viscoelastic can also be used in cases of obstruction that 75% achieved a complete 3600 trabeculotomy
to open the canal by injecting the viscoelastic through a using microcatheter; whereas 25% achieved a partial
special cannula provided for such purpose. Failure to trabeculotomy. The postoperative reduction in IOP from
achieve a circumferential (3600) catheterization is dealt by baseline was statistically significant at the 1-, 3-, and
converting the procedure into conventional trabeculotomy 6-month follow-up visits (p≤0.001). At 6 months, IOP
using a Harms trabeculotome (Figure 12). was significantly lower in the complete as compared to
In rare instances, iris prolapse can occur after trabeculotomy the partial trabeculotomy cohort (p=0.03) with average of
which can be managed by gently repositing the iris and 47% reduction in IOP at 6months. Average medication use
tightly suturing the sclera flaps (Figure 13). was not significantly reduced from baseline at any interval
Past studies on IMCT – a review (p=0.37 at 6months). Of the reported complications there
Studies in the literature have evaluated the surgical were 7 cases (43.8%) of transient hyphema. Secondary
effectiveness of this procedure in treatment of congenital surgical procedures for control of IOP were performed in
glaucomas; however there are no prospective studies. 12.5% eyes. Girkin et al24 conducted a retrospective chart
study in a heterogenous population of congenital/ juvenile
glaucoma in 11 eyes of 7 patients using IMCT. Mean IOP

42 l DOS Times - Vol. 20, No. 1 July, 2014

Glaucoma

IMCT - Merits and demerits – comparision with other
conventional surgeries

Merits Demerits

Enables precise localisation Technically demanding;
ofcatheter;falsepassageinto steep learning curve
subretinal/ suprachoroidal
space averted (possible
with manual or suture
trabeculotomy)

Treats entire circumference Incidence of hyphema
of trabecular meshwork is more (less with other
(manual trabeculotomy conventional surgeries)
treats the angle partially)

Figure 12: Convertion into conventional trabeculotomy in No bleb/ antimetabolite Excessive cost
case of repeated obstruction or misdirecion associated complications
(possible risk of
Figure 13: Iris prolapse after 3600 trabeculotomy trabeculectomy - bleb leak,
blebitis, bleb fibrosis etc)

Post-operative scarring is
less (trabeculectomy has
more chances of fibrosis)

Can also be performed in
eyes with failed primary
surgery like goniotomy or
trabeculectomy

Can be performed in
temporal quadrant sparing
the superior site for future
filtration surgeries if
required

Can be performed in hazy
corneas unlike suture
trabeculotomy which
requires gonioscopic
verification

(mm Hg) was reduced from 33.8±6.3 preoperatively to Our experience in 20 eyes of primary congenital
18.3±3.5 at the final postoperative visit (P-value<0.001). glaucoma
A qualified success was seen in 90.1% of eyes and an A prospective interventional study was carried out in 20
unqualified success in 81.8%. Transient hyphema was eyes of 14 patients with PCG aged ≤ 1 years at the time of
seen in all cases but no long-term surgical complications surgery. Trabeculotomy was performed via an illuminated
were seen. Girkin, Rhodes et al25 compared goniotomy microcatheter (Glaucolight) with intent to perform
with illuminated microcatheter trabeculotomy in 24 eyes complete 3600 catheterization. In cases where complete
of 20 patients. Microcatheter-assisted circumferential catheterization of the Schlemm’s canal could not be
trabeculotomy demonstrated a 91.6% qualified and 83.3% achieved, ab-externo trabeculotomy was performed using
unqualified success rate with 12 - month follow-up that a Harms trabeculotome. All patients were followed up for
exceeded the 53.8% qualified and 46.2% unqualified a period of 12 months with examination under anesthesia
success rate of conventional goniotomy. This procedure at 4 weeks, 12 weeks, 24weeks and 12 months. At the
has also been evaluated in the initial surgical treatment time of presentation, mean IOP was 21.53 ± 8.65 mmHg
of medically refractory aphakic glaucoma and juvenile (on a single topical anti-glaucoma medication), corneal
open angle glaucoma with promising results and few diameters were 13.23 ± 1.52mm (horizontal) and 12.68
complications26.

www. dosonline.org l 43

Glaucoma

±1.31mm (vertical) and vertical cup to disc ratio was 0.75 9. Walton DS, Glaucoma in infants and children. In: Nelson L, Calhoun
± 0.15. Of the 20 eyes, a complete 3600 catheterization JH, Harley RD, eds. Pediatric Ophthalmology. Philadelphia, PA: WB
and circumferential trabeculotomy was achieved in 16 Saunders;1983.
(80%) eyes and a partial catheterization in 4 (20%) eyes
with the need of conversion into usual trabeculotomy. 10. Smith R. Nylon filament trabeculotomy in glaucoma. Trans
Partial catheterization was due to either misdirection of Ophthalmol Soc U K. 1962;82:439-454.
the probe posteriorly into a collector channel (Fig.11
and 12) or obstruction within the Schlemm’s canal. Mild 11. Beck AD, Lynch MG. 360 degree trabeculotomy for primary
transient hyphema was found in all eyes. In one eye there congenital glaucoma. Arch Ophthalmol. 1995;113:1200-1202
was iris prolapse after performing 3600 trabeculotomy. No
other intraoperative complications were noted. There was 12. Verner-Cole EA, Ortiz S, Bell NP, Feldman RM. Subretinal suture
48.28% decrease in IOP (p=0.003) and 17.5% reversal of misdirection during 360 degrees suture trabeculotomy. Am J
cup to disc ratio (p=0.01) at the end of 12 months follow- Ophthalmol. 2006 Feb;141(2):391-2.
up compared to the preoperative values. No postoperative
complications were noted during the entire follow up. 13. Gloor BR. Risks of 3600 trabeculotomy
Single topical antiglaucoma medication to control IOP Ophthalmologe.1998;95:100-103
was needed in 2 eyes in which partial trabeculotomy was
performed. At the end of 12 months follow up, an absolute 14. Neely DE.False passage: a complication of 360 degrees suture
success (defined as an IOP < 15mm Hg) was seen in 92% trabeculotomy. J AAPOS. 2005 Aug;9(4):396-7.
of eyes and a qualified success (defined as an IOP < 15
mm Hg with the use of topical anti-glaucoma medications) 15. Mandal AK, Bhatia PG et al. Safety and efficacy of simultaneous
was seen in 100% of eyes. No patients required a second bilateral primary combined trabeculotomy-trabeculectomy for
surgery to control IOP at 12 months follow-up. There was developmental glaucoma.Indian J Ophthalmol. 2002 Mar; 50(1):13-
no significant change in corneal diameters throughout the 9.
follow-up.
16. Campos-Mollo E, Moral-Cazalla R, Belmonte-Martínez J.Combined
Conclusion trabeculotomy-trabeculectomy as the initial surgical procedure of
Circumferential trabeculotomy performed with an primary developmental glaucoma. Arch Soc Esp Oftalmol. 2008
illuminated microcatheter is a safe and effective technique Aug;83(8):479-85.
to reduce IOP in PCG and can be advocated as a
primary procedure in the treatment of primary congenital 17. Al-Hazmi, Awad et al. Correlation between surgical success
glaucoma. Further comparative studies are required to rate and severity of congenital glaucoma. Br J Ophthalmol. 2005
evaluate the long-term success and safety of this procedure Apr;89(4):449-53.
and to explore its possible role in the treatment of other
developmental glaucomas. 18. Lawrence SD, Netland PA. Trabeculectomy Versus Combined
Trabeculotomy-Trabeculectomy in Pediatric Glaucoma. J Pediatr
References Ophthalmol Strabismus. 2012 Jul 17:1-7. doi: 10.3928/01913913-
20120710-06. [Epub ahead of print]
1. Papadopoulos M, Cable N, Rahi J, et al. The British Infantile and
Childhood Glaucoma (BIG) Eye study. Invest Ophthalmol Vis Sci. 19. Sidoti PA, Belmonte SJ, Liebmann JM, Ritch R.Trabeculectomy
2007;48(9):4100-4106 with mitomycin-C in the treatment of pediatric glaucomas.
Ophthalmology. 2000 Mar;107(3):422-9.
2. DeLuise VP, Anderson DR. Primary infantile glaucoma (congenital
glaucoma). Surv Ophthalmol. 1983;28(1):1-19 20. Rodrigues AM, Júnior AP, Montezano FT, de Arruda Melo PA, Prata
J Jr. Comparison between results of trabeculectomy in primary
3. Dandona L, Williams JD, Williams BC, Rao GN. Population congenital glaucoma with and without the use of mitomycin C. J
based assessment of childhood blindness in southern India. Arch Glaucoma. 2004 Jun;13(3):228-32.
ophthalmol. 1998;116:545-546
21. Matsuda T, Tanihara H, Hangai M, Chihara E, Honda Y.Surgical
4. Maumenee.The pathogenesis of congenital glaucoma; a new theory. results and complications of trabeculectomy with intraoperative
Am J Ophthalmol. 1959 Jun;47(6):827-58 application of mitomycin C. Jpn J Ophthalmol. 1996;40(4):526-32.

5. Maumenee. Further observations on the pathogenesis of congenital 22. Agarwal HC, Sood NN, Sihota R, Sanga L, Honavar SG.Mitomycin-C
glaucoma. Am J ophthalmol. 1963 jun;55:1163-76. in congenital glaucoma. Ophthalmic Surg Lasers. 1997
Dec;28(12):979-85.
6. Anderson DR. The development of trabecular meshwork and its
abnormality in primary infantile glaucoma. Tr Am Ophthalmol Soc 23. Sarkisian SR Jr. An illuminated microcatheter for 360-degree
1981;79:458-485 trabeculotomy [corrected] in congenital glaucoma: a retrospective
case series. J AAPOS. 2010 Oct;14(5):412-6.
7. Agarwal, Sood et al. Clinical presentation of congenital glaucoma.
Indian J Ophthalmol. 1983 Sep;31(5):619-22 24. Girkin CA, Marchase N, Cogen MS.Circumferential
trabeculotomy with an illuminated microcatheter in congenital
8. Shrader CE, Cibis GW. External trabeculotomy. In: Thomas JV, glaucomas. J Glaucoma. 2012 Mar;21(3):160-3. doi: 10.1097/
Belcher CD III, Simmons RJ, eds, Glaucoma Surgery . St.Louis, MO: IJG.0b013e31822af350.
CV Mosby;1992:123-131.
25. Girkin CA, Rhodes L, McGwin G, Marchase N, Cogen MS.
Goniotomy versus circumferential trabeculotomy with an
illuminated microcatheter in congenital glaucoma. J AAPOS. 2012
Oct;16(5):424-7.

26. Dao JB, Sarkisian SR Jr, Freedman SF.Illuminated Microcatheter-
facilitated 360-Degree Trabeculotomy for Refractory Aphakic and
Juvenile Open-angle Glaucoma. J Glaucoma. 2013 May 8.

44 l DOS Times - Vol. 20, No. 1 July, 2014

Ganglion Cell Complex Scan for GlaGulacuocomma
Comprehensive Assessment of Glaucoma
Rupsanchita H. Das
DO

Rupsanchita H. Das DO, Manoj Rai Mehta MD
Aster Eye Care, Tagore Garden, New Delhi

The Ganglion Cell Complex (GCC) scan provides new Figure 1: GCC in a normal eye (left side) and GCC in a glaucomatous
parameter for glaucoma diagnosis. GCC scan is done eye (right side) showing distinct thinning. The white lines showing
for comprehensive assessment of glaucoma in all our ganglion cell complex (GCC) inner and outer boundaries
patients. OCT machine used was RTVue fourier domain
OCT. It has been shown that glaucoma predominantly Advantage of Doing a GCC SCAN
causes thinning of the nerve fiber, ganglion cell and inner The macula contains 50% of all ganglion cells in the retina
plexiform layer, and moderately affects the inner nuclear but the nerve fibre layer is very thin in the macula and is
layer and does not affect the outer layers. The diagnosis absent in the foveola, as the cells are displaced to create the
of glaucoma was improved by concentrating on GCC. fovea pit. In this perifoveal region the nerve fibre layer is
The GCC scan is compared to the normative database and very thin but the ganglion cell layer and the inner plexiform
the result are displayed in color coded maps. These maps layer are thicker. The GCC scan allows the ganglion cell
provide pixel by pixel comparison of the measured results integrity to be assessed in this region with the highest
of the database. Visual fields mainly test peripheral points concentration of ganglion cells .
but the GCC scan is a more central test. GCC Scan Pattern
What is Ganglion Cell Complex? Glaucoma damages the ganglion cells in the macula
Ganglion cell complex thickness is defined by the distance causing retinal thinning. This was first hypothesized and
from the internal limiting membrane (ILM) to the inner demonstrated by Ran Zeimer using the scanning retinal
plexiform layer (IPL) which composes the inner three layers thickness analyzer3.
of the retina1. The GCC scan also includes a horizontal line scan at the
1. The retinal nerve fiber layer. (RNFL) middle for registration of vertical scan and foveal centre.
2. The ganglion cell layer. (GCL) In total the GCC scan captures 15,000 data points within
3. And the inner plexiform layer. (IPL)
All these three layers are affected in glaucoma.
What Happens to the Ganglion Cell Complex in
Glaucoma?
As the ganglion cell dies, the ganglion cell layer becomes
thinner and the axons in the nerve fiber that is a part of that
cell also is lost causing thinning of the nerve fiber layer.
The cell dendrites are located in the inner plexiform layer
and when the cell dies the dendrites are lost and inner
plexiform layer also becomes thin.

www. dosonline.org l 47

Glaucoma

1. Thickness map : It reflect the thickness of GCC
2. Deviation map : It reflects the percentage of loss

from normal and darker colors
represent greater loss.
3. Significance map : It gives the p-value classification
at each data point.

Figure 2: The GCC scan consist of 15 vertical line scans covering
a 7mm square region and the scan centers at 1mm temporal to the

foveal center for better coverage of temporal region.

0.6 second. The OCT scan are processed automatically to Scan 1
provide a thickness map of the GCC scan.
map at the top and the significance map below. The
GCC Display Maps parameter table is on the left side of the report.
The significance map shows areas with suspicious or
The GCC scan results are displayed in three maps borderline results (yellow areas) and a smaller area inferiorly
that is abnormal (red areas).
Scan 1 When interpreting the GCC significance map we look for
abnormal defect (red areas) that is larger than foveal mask
In a GCC scan all the parameters are labelled with Color (1.5 mm circle).
to indicate if there is significant ganglion cell complex In this patient the abnormal areas do not exceed this size,
thickness loss (p<1% red, p<5% yellow, p>5% green). making these results borderline or suspicious of possible
early damage.
Probability values are assigned to an individual measure Scan 3
based on a comparison data. This is done by determining The thickness map shows large areas of dark blue and
where in the normal distribution an individual value black indicating extensive damage where 30% to 50% of
falls. The p-value reflects the relative location of a given ganglion cell complex thickness has been lost.
measure to the normative database. If the p-value is very Deviation map
low it indicates higher chances of the presence of ocular The deviation map shows large black areas which indicates
pathology. 50% ganglion cell complex loss compared to the normative
data base.
A given result is color coded based on this classification Scan 4
where The significance map of the same patient showing areas of
significant atrophy.
• Green indicates : within normal limit

• Yellow indicates : borderline

• Red indicates : outside normal limit

Scan 2

The GCC report for a single eye showing GCC thickness

48 l DOS Times - Vol. 20, No. 1 July, 2014

Glaucoma

Scan 2 Scan 3

The damage is almost completely covering the superior Scan 4
portion and also extends inferiorly leaving only some
amount of area inferotemporally. 2. Ishikawa H, Stein DM, Wollstein G, et al. Macular segmentation
The damage is very extensive and advanced. with optical coherence tomography. IOVS. 2005;46:2012–17.
There are numerous validation studies on the GCC SCAN.
Takagi, et al. showed the GCC analysis significantly detected 3. Zeimer R, Asrani S, Zou S, et al. Quantitative detection of
thinning in eyes with visual field in one hemisphere and glaucomatous damage at the posterior pole by retinal thickness
significantly correlated with severity of visual field loss4. mapping: A pilot study. Ophthalmol. 1998;105:224–31.
Mori, et al. showed the GCC analysis significantly
differentiated normal from glaucoma5.
They also showed that GCC analyses significantly correlated
with electrophysiology results in glaucoma patients. This
suggest thickness values accurately reflect the severity5.
Conclusion
The GCC scan provides new parameters for glaucoma
diagnosis. The GCC scan quantifies the thickness in all the
three layers of the retina that is affected by glaucoma. The
GCC scan provides assessment of the retinal nerve fiber
layer, the ganglion cell layer and inner plexiform layer
information in the macular region. This comprehensive
assessment of the major structures affected by glaucoma
has great potential for improving clinical care for glaucoma.
References

1. Tan O, Chopra V, Lu AT, et al. Detection of macular ganglion cell
loss in glaucoma by Fourier-domain optical coherence tomography.
Ophthalmol. 2009;116:2305–14.

www. dosonline.org l 49

Glaucoma

4. K. Kagish Nose A. et al. Inner Retinal Layer Measurements in Macular 5. Mori S., Hangai M., Nakanishi H., et al. Macular Inner and
Region With Fourier Domain Optical Coherence Tomography Total Retinal Volume Measurement by Spectral Domain Optical
in Glaucomatous Eyes With Hemifield Defects. Toho University Coherence Tomography for Glaucoma Diagnosis. Kyoto University,
Ohashi Medical Center, Tokyo, Japan, IOVS 2008: Suppl. 4648. Kyoto, Japan IOVS 2008: Suppl. 4651.

Forthcoming Academic Events

6th DOS Teaching Programme** Sir Ganga Ram Hospital
14th & 15th June, 2014 (Saturday & Sunday)
(DOS Monthly Clinical Meeting)*
Safdarjung Hospital*
25th January, 2015 (Sunday)
(DOS Monthly Clinical Meeting)*
Bharti Eye Hospital
27th July, 2014 (Sunday)
(DOS Monthly Clinical Meeting)*

22nd February, 2015 (Sunday)

Centre For Sight

(DOS Monthly Clinical Meeting)*

29th March, 2015 (Sunday)

DOS Winter Conference

DOS Teaching Programme

AIOS 2015
DOS Annual Conference 2015

*Monthly Academic & Teaching Programme
**Teaching Programe for postgraduate students in Ophthalmology

50 l DOS Times - Vol. 20, No. 1 July, 2014

GlaGulacuocomma

Post- Penetrating
Keratoplasty Glaucoma

Mainak Bhattacharyya

MBBS

Mainak Bhattacharyya MBBS, Neha Rathie MBBS, Ritu Arora MD, DNB, Parul Jain MS, FICO
Guru Nanak Eye Centre, New Delhi

Irvine and Kaufman (1969) were the first to describe an Full thickness keratoplasty vs. lamellar
association between penetrating keratoplasty (PK) and keratoplasty
glaucoma1. Post-penetrating keratoplasty glaucoma (PPKG) Since there is no disruption of Descemet’s membrane in
is one of the most challenging problems because of its deep anterior lamellar keratoplasty (DALK), there should
frequent occurrence, difficult diagnosis, recalcitrant nature, be no distortion of the anterior chamber angle, which is
irreversible visual loss due to damage to optic nerve as well thought to be a major mechanism leading to PPKG. Also,
as the donor endothelium and management difficulty. the stromal bed left behind the Descemet’s membrane
should theoretically be protective against drainage angle
Definition distortion. Although it is associated with a lower incidence
Post-PK glaucoma is defined as an elevated intra-ocular of increased IOP as compared to PK, yet it is a significant
pressure (IOP) greater than 21 mmHg, with or without (0-18%).
associated visual field loss or optic nerve head changes, at
any time during the post operative period. Mechanisms of glaucoma6
Early postoperative period
Magnitude of the problem • Pre-existing open angle glaucoma / peripheral anterior
Rise in IOP following keratoplasty has been reported to
be a biphasic phenomenon. The incidence of glaucoma synechiae (Figure 1)
after keratoplasty varies from 9% to 31% in the early • Inflammation
postoperative and 18% to 42% in the late postoperative • Hyphaema
period2.

Risk Factors3-5

Pre-operative Intra-operative Post-operative

• Age more than 60 years • Tight suturing • Development of fine or broad based PAS
• Preexisting glaucoma • Larger trephine sizes • Significant angle damage due to
• Aphakia • Long bites of individual sutures development of PAS or severe intraocular
• Preoperative diagnosis of: • Increased peripheral corneal inflammation
ü Adherent leukoma thickness • Post operative steroid use
ü Bullous keratopathy • Graft host disparity (donor size
ü Herpetic keratitis smaller than host)
ü Trauma
ü Perforated corneal ulcer
ü Graft rejection
ü Mesodermal dysgenesis

Keratoplasty performed for keratoconus and corneal dystrophies are associated with a significantly lower risk of post- PK glaucoma.

www. dosonline.org l 51

Glaucoma

Figure 1: Slit lamp photograph showing PAS Figure 2: Gonioscopic view showing PAS in a case of post PK
post keratoplasty glaucoma (source: Dada T et al, Post penetrating keratoplasty

glaucoma. Indian J Ophthalmol 2008)8

• Pupillary block • Tono-pen
• Retained viscoelastic material • Dynamic contour tonometer (DCT)
• Blockage of peripheral iridectomy in case of an infected • Goldmann applanation can be used to measure the IOP

etiology if the graft surface is smooth with an intact epithelium.
• Compression of the anterior chamber angle • Corneal epithelial edema and stromal edema predispose
• Collapse of the trabecular meshwork:
Zimmerman et al proposed that mechanical collapse of the to inaccurately low readings, whereas corneal scarring
trabecular meshwork in aphakic grafts is responsible for the will cause falsely high recording.
higher incidence of secondary glaucoma7. They postulated Optic disc evaluation
that ciliary body-lens support system lends posterior On every follow up with imaging at first examination and
fixation to the trabeculum while an anterior support is then subsequently at least once a year is recommended to
afforded by the Descemet’s membrane. In aphakia, the detect any progression of glaucomatous optic neuropathy.
posterior support is relaxed with the removal of the lens Visual field testing
while anterior support is relaxed post PK after Descemet’s May be difficult to perform in patients with a corneal graft,
excision which leads to a partial trabecular collapse and especially in the early postoperative period.
obstruction of aqueous outflow. Gonioscopy
Late postoperative period Provides assessment of peripheral anterior synechiae in the
• Progressive synechial closure post operative period but is impossible in case of a failed
• Steroid induced graft where corneal edema precludes the visualization of
• Pupillary block anterior segment structures8 (Figure 2).
• Rejection/ inflammation sequelae Ultrasound biomicroscopy (UBM)
Diagnosis Used to assess the angle and establish the cause for post-
IOP measurements PK glaucoma, especially in eyes with a failed graft where
• In the early postoperative period, when the corneal anterior segment details are not clearly visible. The extent
of irido-corneal adhesions, phakic/aphakic status, location
surface is irregular, IOP can measured using of intraocular lens (IOL), anterior chamber (AC) depth,
• Mackay-Marg electronic applanation tonometer angle width and corneal thickness can be determined using
• Pneumatic applanation tonometer UBM. In a UBM study done in eyes with post keratoplasty
glaucoma, UBM showed the actual site of synechiae, viz.
peripheral anterior synechiae, synechiae at the graft host

52 l DOS Times - Vol. 20, No. 1 July, 2014

Glaucoma

Figure 3: PAS on UBM (copyright owner Figure 4: AS-OCT showing edge of
Lippincott, Williams and Wilkins, 2008) graft and PAS

junction, host junction synechiae, central irido-corneal • In the postoperative phase
synechiae and intraocular lens iris synechiae9 (Figure 3).
It was thus concluded that UBM, serves as a useful tool • optimum use of steroids
for anterior segment evaluation in such cases and can help
in planning the site for glaucoma filtering surgeries and • use of cycloplegics to keep the pupil mobile and
drainage devices. prevent pupillary block glaucoma
Anterior segment OCT
As compared to UBM, AS-OCT requires no contact or Medical management
immersion for evaluation of the depth of the anterior
chamber angle and the causes of secondary angle closure10 • Medical control of IOP is the first line of treatment for
(Figure 4). post keratoplasty glaucoma.
Management
Preventive Measures • Currently available medications include:
• Prior to keratoplasty
Pre-existing glaucoma should be appropriately managed • Beta-adrenergic blocking agents (timolol,
either medically or surgically betaxolol)
• During keratoplasty
• use of an oversized donor button (0.5 mm) • Alpha-2-adrenergic agonists (brimonidine,
• deep, short and equal bites apraclonidine hydrochloride)
• goniosynechiolysis in the presence of peripheral
• Miotics (pilocarpine, echothiophate iodide, and
anterior synechiae carbachol)
• iridoplasty in cases of floppy iris
• removal of viscoelastic material at the end of the • Prostaglandin analogues (latanoprost, bimatoprost
and travoprost)
procedure
• careful wound closure to prevent postoperative • Adrenergic agents (epinephrine & dipivefrin) are rarely
used in current practice, as they are not very effective
wound leaks and cause chronic conjunctival inflammation.

• Miotics have little effect in the presence of angle
closure caused by PAS and no longer recommended.
They also promote breakdown of blood aqueous
barrier, stimulating graft rejection and increasing the
risk of retinal detachment, particularly in aphakes.

• Topical carbonic anhydrase inhibitors (dorzolamide
and brinzolamide) suppress carbonic anhydrase
enzyme in the corneal endothelium and long-term

www. dosonline.org l 53

Glaucoma

Possible disadvantages of the various anti-glaucoma medications in patients with post-keratoplasty glaucoma

Anti- glaucoma medication Potential Side effects

Beta-Blockers SPK, corneal anesthesia, dry eyes.

Alpha adrenergic drugs SPK, dry eyes, allergic reactions.

Miotics Inflammation, graft rejection, retinal detachment

Topical Carbonic anhydrase inhibitors Altered taste, permanent graft failure in eyes with borderline endothelial
counts.

Systemic Carbonic anhydrase inhibitors Nausea, gastrointestinal disturbances, paresthesias, tinnitus, fatigue,
depression, anorexia, weight loss, nephrolithiasis, and blood dyscrasias.

Prostaglandin analogues Uveitis, cystoid macular edema in aphakia and pseudophakia and recurrent
herpes simplex infection in patients with previous history of herpes.

Benzalkonium chloride, the preservative in most topical glaucoma medications, is toxic to the corneal epithelium

use can lead to graft decompensation especially in applied for 1-4 min subconjunctival or sub-scleral)
presence of borderline corneal endothelial status. has remarkably improved the success rate of filtering
surgery for glaucoma.
Surgical Management • The reported success rate in IOP control with
Laser trabeculoplasty mitomycin trabeculectomy in patients with post-PK
Argon laser trabeculoplasty glaucoma is 67-91% and that of graft failure is 12-
Indications 18%13. These agents appear to increase the success rate
• Patients with open angles by inhibiting the fibroblast proliferation and enhancing
• Clear grafts and the formation of filtering blebs.
• Moderately elevated IOP (20-25 mmHg) on anti- • Glaucoma drainage devices (GDD).
• Offer an effective means for IOP control when filtering
glaucoma medications. surgeries are less likely to be successful.
Recommended settings • Create alternate aqueous pathways by channeling
50-µ spot size, 0.1-sec duration, and 600-900 mW of aqueous humor from the anterior chamber through
power11. a long tube to an equatorial plate that promotes bleb
Complications formation (Figure 5).
Post-operative IOP spikes and uveitis, which can trigger • There are two types of GDDs, which can be used:
graft rejection12. (1) Valved devices -offer resistance to outflow (Ahmed
• Diode laser trabeculoplasty and selective laser
valve; Krupin implant)
trabeculoplasty may also be used. (2) Valveless – offer no resistance to outflow (Molteno

Laser iridotomy implant, Baerveldt implant).
May be performed with an Nd:YAG (neodymium:yttrium- • The advantages of the valved devices especially that
aluminium-garnet) laser, if a pupillary block is suspected.
of the Ahmed glaucoma valve, is the ease of insertion
Trabeculectomy and low incidence of hypotony in the immediate
• In cases non-responsive to either medical therapy or post-operative phase. However, the Ahmed valve is
associated with a high incidence of increased IOP-
ALT, trabeculectomy is advised. hypertensive phase (as much as 80%), 1-3 months
• Conventional trabeculectomy is usually not effective, after the procedure, which may need needling and
5-FU injections. Drainage devices with a larger surface
attributed to limbal conjunctival scarring from previous area, such as the double-plate Molteno and Baerveldt
surgery, extensive peripheral synechiae, aphakia, and implant, on the other hand, appear to exhibit a lesser
extremely shallow anterior chamber. incidence of the hypertensive phase and may achieve
• Antimetabolites like 5- fluorouracil (5 mg of 5 FU in slightly lower IOPs in the long term.
0.1 cc is given daily as a subconjunctival injection for • The overall success rate and other complications,
7-10 days) and Mitomycin-C application (0.2-0.4 mg including corneal decompensation, appear to be
similar among all GDDs14-15.

54 l DOS Times - Vol. 20, No. 1 July, 2014

Glaucoma

Figure 5: AGV in an eye with DALK (Source: Al-Mahmood AM et al. Transpupillary argon laser photocoagulation
Glaucoma and corneal transplant procedures. J Ophthalmol 2012)16 Another modality that describes use of Goldmann three-
mirror lens to ablate the ciliary processes one at a time. The
• Complications laser is set at 50-100 µm spot size for a duration of 0.1-0.2
• Graft failure sec with a power of 1000 mW.
A high incidence of graft failure (average 36.2%) is
associated with the use of GDD’s. Conclusion
The drainage tube may provide a conduit for retrograde Post- penetrating keratoplasty glaucoma remains one of the
passage of inflammatory cells into the AC thus increasing leading causes of graft failure and
the risk of graft failure. visual loss. Knowledge of the risk factors such as pre-
• Shallow AC with iris/ tube graft endothelial touch - existing glaucoma, aphakia and previous PK may help
to limit the occurrence of glaucoma and to increase the
might accelerate the process leading to graft failure. chances of success of PK. Timely diagnosis of PPKG along
• Conjunctival erosion with aggressive and timely management remains the
• Prolonged hypotony cornerstone for preserving optimal graft clarity and visual
• Tube obstruction/ failure/ tube plate extrusion function following keratoplasty procedures.
• Epithelial down growth
• Infection. References
Cyclodestructive procedures
• Used as the surgical procedure of choice in difficult and 1. Irvine AR. Kaufman HE. Intraocular pressure following penetrating
keratoplasty. Am J Ophthalmol 1969;68:835-44.
advanced cases when medical or surgical interventions
fail to control the IOP. 2. Foulks GN. Glaucoma associated with penetrating keratoplasty.
• Control the IOP by decreasing aqueous humor Ophthalmology 1987;94:871-4.
production by destroying part of the ciliary body.
• Cyclocryotherapy,NdYAGlasercyclophotocoagulation 3. Ayyala RS. Penetrating keratoplasty and glaucoma. Surv Ophthalmol
(CPC), Diode laser cyclophotocoagulation (DLCP) 2000;45:91-105.
using cryoprobe, Neodymium: Yttrium-Aluminium-
Garnet (Nd:YAG) laser or a semiconductor diode 4. Sihota R, Sharma N, Panda A, Aggarwal HC, Singh R. Post
respectively are the various options available. penetrating keratoplasty glaucoma: Risk factors, management and
Complications include decrease in the Snellen visual visual outcome. Aust NZJ Ophthalmol 1998;26:305-9.
acuity, graft failure, persistent hypotony, anterior uveitis,
epithelial defects, severe pain, phthisis bulbi, hyphema, 5. Sharma A, Sharma S, Pandav SS, Mohan K. Post penetrating
hypotony, intractable pain, sympathetic ophthalmia, scleral keratoplasty glaucoma: cumulative effect of quantifiable risk factors.
thinning, and vitreous hemorrhage. Indian J Ophthalmol. 2014 May;62(5):590-5.

6. Allingham R R, Damji K, Freedman S, Moroi S, Rhee D J. Shields
textbook of glaucoma. 6th ed. 2011; p.376-7.

7. Zimmerman TJ, Krupin T, Grodzki W, et al: The effect of suture depth
on outflow facility in penetrating keratoplasty. Arch Ophthalmol.
1978;96:505–6.

8. Dada T, Aggarwal A, Minudath KB, Vanathi M, et al. Post-
penetrating keratoplasty glaucoma. Indian J Ophthalmol. 2008 Jul-
Aug;56(4):269-277.

9. Dada T, Aggarwal A, Vanathi M, Gadia R, Panda A, Gupta V, et al.
Ultrasound biomicroscopy in opaque grafts with post penetrating
keratoplasty glaucoma. Cornea 2008; 27:402-5.

10. Gupta P, Sharma A, Ichhpujani P. Post penetrating keratoplasty
glaucoma- A review. Nepal J Ophthalmol. 2014;6(11):80-90.

11. Van Meter WS, Allen RC, Waring GO 3d, et al: Laser trabeculoplasty
for glaucoma in aphakic and pseudophakic eyes after penetrating
keratoplasty. Arch Ophthalmol 1988;106:185–8.

12. Shingleton BJ, Richter CU, Bellows AR, et al: Long-term efficacy of
argon laser trabeculoplasty. Ophthalmology 1987;94:1513–8.

13. Ayyala RS, Pieroth L, Vinals AF. Comparison of mitomycin C
trabeculectomy, glaucoma drainage device implantation and laser
neodymium YAG cyclophotocoagulation in the management of
intractable glaucoma after penetrating keratoplasty. Ophthalmology.
1998;105:1550-6.

14. Abdulla Al-Torbak. Graft survival glaucoma outcome after
simultaneous penetrating keratoplasty and Ahmed glaucoma valve
implant. Cornea 2003;22:194-7.

15. Sidoti PA, Mosny AY, Ritterband DC, Seeder JA. Pars plana
tube insertion of glaucoma drainage implants and penetrating
keratoplasty in patients with coexisting glaucoma and corneal
disease. Ophthalmology 2001;108:1050-8.

16. Ammar M. Al-Mahmood, Samar A. Al-Swailem, Deepak P. Edward.
Glaucoma and corneal transplant procedures. J Ophthalmol.
2012.2012:5763-94.

www. dosonline.org l 55

Posterior Segment DiaDginagonsotsitcicss
Imaging in Glaucoma
Anita Ganger
MS, FAICO

Anita Ganger MS, FAICO, Viney Gupta MS
Dr. R.P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi

Glaucoma is a chronic progressive optic neuropathy been focused on objective methods to aid in the diagnosis
with typical optic disk and retinal nerve fibre layer of glaucoma.
(RNFL) changes with corresponding visual field defect. Glaucomatous damage can be assessed in two ways2:
Intraocular pressure (IOP) is not a diagnostic criteria but • Evaluation of Glaucomatous Structural Damage.
considered only a major risk factor. Evolution of Imaging • Optic disk photography.
technology over the past few years has made management • Confocal scanning laser ophthalmoscopy (HRT).
of the glaucoma patient and glaucoma suspect more • Scanning laser polarimetry (GDx VCC).
interesting. Several imaging modalities are there i.e • Optical coherence tomography (OCT).
Stereoscopic disc photography, HRT, GDx, time domain • Evaluation of Glaucomatous Functional Damage.
OCT, spectral domain OCT. There has been considerable • Standard Automated Perimetry (SAP).
debate among glaucoma specialists regarding the use • Short-Wavelength Automated Perimetry (SWAP).
of these imaging modalities and to ascertain which one • Frequency-Doubling Technology Perimetry (FDT).
is superior to the others to help diagnose glaucoma and In this article detailed description of various tests to evaluate
monitor its progression1. glaucomatous structural damage would be discussed.
First Things First Disc photography (DP)
Imaging tests should always be used in conjunction with DPs more commonly appear as two-dimensional images
your exam and visual fields. Although these provides on the computer screen, although 3-D viewing is also
objective measurements of various parameters of the possible with the use of various devices. Hence, 2-D
posterior segment which can be compared from visit photos should only be compared to prior DPs only because
to visit. One should not solely rely on them to diagnose with biomicroscopy viewing of neuroretinal rim on 2-D
glaucoma or to monitor progression. photos usually appears thicker than the actual ONH.
Before jumping into imaging one should always perform Special attention to the relative position of blood vessels
a careful ophthalmic examination which includes viewing at the neuroretinal rim and there migration toward the disc
of optic nerve head (ONH) with a 78D or 90D lens at the margin should be checked if progression suspected3.
slit lamp. Typical characteristics of glaucomatous optic Pros
neuropathy should be noted which includes: • Helpful in diagnosing slow progressors or glaucoma
• Cupping
• Notching of the neuroretinal rim suspects as side-by-side DPs spanning 10 years or more
• Disc hemorrhage can be compared.
• Nasalization of blood vessels
Clinical examination of the ONH and RNFL is subjective
and therefore prone to variability so recent researches have

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Diagnostics

Cons Figure 1: Relationship between the ONH, the contour line
• Provides qualitative assessment of the ONH only and the reference plane

[dependent on the viewer and also the mode of viewing Figure 2: The printout provides topography
(2-D versus 3-D)]. measurements and a classification of the parameters
• Require dilation. based on a comparison with a normative database
• Quality of DP is operator-dependent.
• Difficult to compare if DPs are taken with different 4. Horizontal height profile: This is available in HRT
devices or different settings (lighting, viewing angle, II printout. Horizontal profile represents the height
magnification). profile along the white horizontal lines across the
Confocal scanning laser ophthalmoscopy (HRT) ONH in the topography image. The parallel red line on
Principle: Based on confocal scanning laser ophthalmoscopy, the graph represents the reference plane and the two
HRT allows acquisition of two-dimensional images of perpendicular black lines represent the borders of the
the optic nerve head (ONH) and reconstruct into three- disc as defined by the contour line previously drawn.
dimensional image. Sequential confocal scans are acquired
in depth at the level of the ONH, and then merged into a 5. Vertical height profile: This is available in HRT II
3D image by the in-built software. The current models are printout. Vertical profile has the same characteristics as
HRTII and HRTIII, which acquire a series of up to 64 optical ‘horizontal profile’ but the height profile represented
sections in depth at intervals of 1/16 mm. is along the vertical lines across the ONH in the
For analysis, a contour line should be manually placed by topography image.
the operator to demarcate the limits of the ONH. In-built
software then places a parallel inferior limit which is in
depth, to the retinal surface, placed 50 microns below the
contour line and known as Reference Plane. Measurements
are made based on this imaginary plane (Figure 1).
Parameter tables
(Figure 2) shows HRT II printout and (Figure 3) shows
HRT III printout. The printout provides topographic
measurements and a classification of the parameters based
on a comparison with a normative database. In HRT III,
the optic disk parameters are compared with ethnic based
normative database.
This table shows the parameters measured from an acquired
scan and its normal range is calculated from a normative
database. The HRT III includes Indian data also(ethnic
specific database). It also provides statistical value
comparing patient result to normative database. Here, p <
0.05 = Borderline, p < 0.001 = Outside Normal Limits.
1. Patient and exam data: This data includes: name, date
of birth, ID number, gender and scan date.
2. Quality score: It is a Topography Standard Deviation
and indicates quality of an image. (A value < 40
usually indicates good-quality images).
3. Mean height contour graph: This is available in HRT II
printout. The green line represents the retinal surface
height profile along the contour line. The red line
represents the reference plane. The dark black line
parallel to the reference plane represents the mean
peripapillary retinal surface height.

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Figure 3: The printout showing comparison of optic disk Figure 4: Moorfield’s regression classification
parameters with ethnic based normative database
normal limits compared to the selected ethnic-specific
6. Reflection image: It is a ‘false’ color picture which normative database.
represents changes in reflectivity for each region of 10. Inter-eye asymmetry: It evaluates the symmetry of the
the ONH., Using the Moorfields regression analysis RNFL profile between eyes. If the correlation between
software it is divided into six sectors, which are eyes is good, the value will be near 0%.
compared with a normative database. This comparison Most important diagnostic criteria for HRT
takes into account the relationship between ONH size 1 Moorfields regression analysis5 (Figure 4): The column
and rim area, and classifies each sector as ‘within normal height represents the ONH (or sector) area. It is divided
limits’ (green tick),‘borderline’ (yellow exclamation into the percentage of rim area (green) and percentage
mark) or ‘outside normal limits’ (red cross). of cup area (red) which is compared with age-matched
data. Based on percentage of rim it is divided in to:
7. Topography image: Topography image is a ‘false’ color • Larger than or equal to the 95% limit, the respective
image representing the height of the scanned area (the
brighter the color the more depressed the region, and sector is classified as ‘within normal limits’. This
vice versa). On the ONH, ‘cup area’ is seen in red and would be marked as a green tick.
‘rim area’ in blue and green (the difference in color • Between the 95% and the 99.9% limits, the
denotes difference in height levels). respective sector is classified as ‘borderline’. This
would be marked as a yellow exclamation mark.
8. Parameters: In HRT II printout provides all optic disc • Lower than the 99.9% limit, the respective sector
and RNFL parameters. In HRT III, along with optic is classified as ‘outside normal limits’. This would
disc size, the software also identifies disc as “small”, be marked as a red cross.
“average”, or “large”. In the HRT printout there is a classification for the whole
disc (1st column) and a classification for each single sector
9. RNFL profile graph: This is available in HRT III printout. (2nd-7th column).
It displays the height values at the optic disc margin 2 FSM discriminant function: Mikelberg et al developed
going around the optic disc from the temporal side, to this. This discriminant function is a linear combination
superior,nasal, inferior, and back to temporal (TSNIT). of the three parameters cup shape measure, rim volume
The green shaded area is the normal range, yellow and contour line height variation. If the discriminant
is borderline, and the red zone indicates outside function value F is positive eye is classified as being
normal; If F is negative it is classified as glaucomatous.
Authors reported sensitivity of 87% and a specificity of
84%6.
3. RB discriminant function: This was developed by
Burk R et al. But this discriminant function has high
specificity with poor sensitivity for diagnosing early
glaucoma.
4. Ranked sector distribution curves: Here, the optic
nerve head is divided into 36 sectors, each 10° wide,
to compute the stereometric parameter values in each

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Diagnostics

segment, and to sort these 36 values in descending Figure 5: GDx VCC printout
order. The result is a graphical representation of the
optic nerve head con-figuration similar to the Bebie Principle GDx VCC involves scanning the retina with a laser
curves used in perimetry. From a normal population beam, which passes through it and reflects from the deeper
data, normal RSD curves; the 5th and 95th percentile layers towards the device that releases the laser beam. The
curves has been calculated. To test a specific eye, its retardation of the reflected light is then measured for an
RSD curve is simply plotted together with the normal estimation of RNFL thickness.
RSD curves. But not widely used for diagnosis. Different features of GDx VCC printout are:
5. Glaucoma probability score (GPS): GPS utilizes large, 1. Patient and exam data: This contains information
ethnic-selectable databases and artificial intelligence
(Relevance vector machine), which derives the about the patient, acquisition site, ID number, name
probability of damage consistent with glaucoma. and surname,gender, ancestry and date of birth.
The GPS provides immediate results and don’t need 2. Image quality: The image quality is shown in the box
drawing of contour lines or relying on reference planes. above the fundus image (scale 1 to 10). The score of 7
It has similar sensitivity and specificity to the Moorfields or more is desirable.
Regression Analysis 3D model combines the optic disk 3. Fundus image: The fundus image is used to check
topographic information with the peripapillary RNFL image quality, focus and illumination, and centring of
information. It uses five parameters: three characterize the ‘ellipse’(black ring around ONH).
the shape of the optic disk (capturing information 4. Thickness map: This map is a color-coded representation
from the cup size, depth and slope of the rim); two of RNFL thickness. Thick RNFLs are colored in yellow,
characterize the RNFL (capturing information from the orange and red (the warmer the color, the thicker the
RNFL curvature both horizontally and vertically across RNFL), while thin RNFL values are colored dark and
the image). A normal result is displayed. using a green light blue (the deeper the blue, the thinner the RNFL).
tick, a borderline result using a yellow exclamation Generalized RNFL loss results in a more uniform blue
point, and an abnormal result using a red X. appearance, and a focal (wedge) defect appears as a
Diagnostic accuracy: HRT is having high diagnostic dark blue band.
accuracy for detecting glaucoma5,7,8. The Moorfields 5. Deviation map: The deviation map tells us the location
Regression Analysis had a sensitivity and specificity of and severity of RNFL defects over the entire thickness
84% and 96% respectively5. An analysis based on the map. It analyses a 20 × 20 degree region centered on
shape of the optic disk and surrounding RNFL resulted the optic disc using a gray scale fundus image of the
in a sensitivity and specificity of 89% and 89%7. GPS eye as a background.The map is averaged into a grid
analysis has a sensitivity and specificity of 91% and of 32 × 32 squares, where each square (super pixel) is
90%8. compared with the age-matched normative database..
Pros
• Can be done through an undilated pupil.
• Superimposition of images taken at different times to
assess progression is possible by upgrading the older
machines with newer software.
• HRT provides quantitative data and presents the
analysis of rim area in a user-friendly manner.
Cons
• Manual-outlining of the disc margin makes comparison
of quantitative data difficult on various visits, especially
when the operators are different.
• Detection of abnormal rim thinning may be
compromised in small or large discs.

Scanning Laser Polarimetry (GDx VCC) (Figure 5)
The GDx VCC is a confocal scanning laser ophthalmoscope
with integrated polarimeter, which uses a near-infrared
laser beam (780 nm) to scan the retina.

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6. TSNIT curve: TSNIT stands for Temporal-Superior- Figure 6: OCT printout (RNFL analysis)
Nasal-Inferior-Temporal. The graph displays RNFL
thickness values calculated within the calculation • No dilation required
circle, starting temporally and moving superiorly, • Yields quantitative data.
nasally, inferiorly, and ending temporally for both eyes • RNFL thickness curves acquired at different visits can
(darker line). The shaded area represents the normal
range for that age. be graphed together to monitor for worsening.
Cons
7. Parameters table • Affected by media opacity, ocular surface, macular
a. TSNIT average: It is the average of the RNFL
diseases and peripapillary atrophy.
thickness within the calculation circle. • Artifact from compensating for poor signal-to-noise
b. Superior averages: This is the thickness measured
ratio.
within the superior 120° • Images taken with older devices cannot be analyzed
c. Inferior averages: This is the thickness measured
for change with the newer device.
within the inferior 120°. Optical Coherence Tomography (OCT)
d. The TSNIT Std. Dev: It represents the standard OCT can be used to scan the ONH, peripapillary retina
and macular region. An 820-nanometer near-infrared light
deviation of the overall measurement: the bigger beam is used, and the reported depth resolution is less than
the number, the healthier the eye. or equal to 10 microns.16-20It is a noncontact, noninvasive
e. Inter-eye symmetry: It is a correlation coefficient imaging technique that provides high-resolution cross-
of the total measurement from both eyes. A value sectional images of the retina.The principle is similar to
close to 1 means high symmetry between eyes. ultrasound but here light is used toscan the retina. The
f. NFI (Nerve Fiber Indicator): It is an indicator of the intensity of light signal reflecting from retinal structures is
likelihood of an eye to have glaucoma. used to create a tomographic image. The combined use
Nerve Fiber Index of low-coherence light and an interferometer provides
The nerve fiber index (or NFI) is based on an advanced form
of neural network analysis, which is trained to differentiate
optimally normal from glaucomatous eyes. The entire
RNFL profile is analyzed, and the diagnostic classification
of the output is determined using the normative database
(data from normal eyes). The 95th percentile is used as
the cut-off for classifying the RNFL as ‘normal’ (between
0 and 30) or ‘borderline’(between 31 and 50). The 99th
percentile is used as the cut-off for classifying the RNFL as
‘glaucomatous’ (between 51 and100)9.
Diagnostic Accuracy
Sensitivity and Specificity of GDx in the early diagnosis
of glaucoma ranges from 72 to 78% and 56 to 92%
respectively10-14. According to literature, no single
parameter have been found with high diagnostic accuracy.
Its a combination of more than one parameter that can be
used to improve the diagnostic accuracy of GDx VCC.
For example, NFI >50 has maximum specificity, positive
likelihood ratio. If positive, it can be used to virtually ‘rule
in’ the disease. NFI < 20 has maximum sensitivity and
negative likelihood ratio. If negative it can be used to ‘rule
out’ the disease.
Pros
• Good sensitivity at detecting RNFL defects, which
correlates well with VF loss.

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