dos_dec_2004

!! DOS Election !!

Applications are invited from Delhi Members of Delhi
Ophthalmological Society for the posts of : Vice President (1 Post),
Secretary (1 Post), Joint Secretary (1 Post), Treasurer (1 Post), Editor
(1 Post), Library Officer (1 Post), & Executive Member (8 Posts).

The eligibility criteria for different post prescribed in DOS
Constitution (1998) will be followed. Application should be submitted
on a plain paper duly proposed and seconded by a member of DOS
(not in arrears). Application should reach Secretary Office latest by
January 30th, 2005 (2 p.m.). Last date of withdrawal is 1st March, 2005
(5 p.m.) Election will be held during the Annual DOS Conference on
3rd April, 2005.

Secretary, DOS

Election Notice

Election will be held for the post of DOS Representative to All India
Ophthalmological Society (2 posts) in the Annual DOS Conference
(April 3rd, 2005). The nomination may kindly be sent to the undersigned
by January 31st, 2005 (2 p.m.). Last date of withdrawal will be March
1st, 2005 (5 p.m.).

Secretary, DOS

!! Attention DOS Members !!

Applications are invited for DOS Fellowship for Partial FinancialAssistance toAttend Conference(s).
The last date for receiving application is 31st January, 2005 for International Conference.

For details please see page no. 218

December, 2004 190 DOS Times - Vol.10, No. 5

EDITORIAL

Dear Colleagues,

DOS Mid Term Conference Nov.2004 was a great MICS is still in the infancy such innovation may
success. I on behalf of DOS Executive extend my sincere overcome the demands of higher generation phaco units
thanks to all the delegates and faculty for making this with cold phaco and advanced fluidics?? Most surgeons
interactive session on “CRISIS MANGEMNET” a still prefer a conventional foldable IOL implantation, the
thumping success. In fact this year we had a record hydrophilic rollable lenses have to stand the test of time
registration for this mid term conference. Single venue specially in terms of higher rate of PCO and chance of
and all the scientific sessions under a one roof covering opacification of IOL. Use of Two ACMs along with one
different specialty gives opportunity to all the delegates irrigating chopper makes this surgery a multi MICS,
and discussants to contribute and also to know what which I personally consider a macro incision surgery.
other specialty people are up to. Like in SCIS single AC maintainer and a conventional
chopper may still be a better option. Good irrigating
Unfortunately we had to begin the session in a sad chopper (20 gauge) usually suffices the need of adequate
note, passing away of Dr. N.C. Singal a night before the inflow for MICS. A peristaltic system use of TUR set and
conference and Prof. L. P. Agarwal a month earlier was shortened irrigation tube length also helps. It would be
a great loss to our society. interesting to note the surgically induced astigmatism
and endothelial cell loss in these eyes with double ACMs
This issue of DOS Times as usual covers all the as compared to routine MICS with irrigating choppers.
specialty areas. Review article by Atul Kumar et.al
beautifully summarizes the recent advances in the field Next is in lines is our mega event Annual DOS
of macular and submacular surgery. Conference. In this issue we are publishing the abstract

Ruchi Goyal and KPS Malik have written an form, so that members can send there abstract early.
interesting article on MICS with two AC maintainers.
Dr. Jeewan S. Titiyal

DOS MONTHLY CLINICAL MEETING FOR DECEMBER, 2004

Venue : Venu Eye Institute & Research Centre, New Delhi

Date & Time : 18-12-04 (Saturday) at 2:30 PM

Case Presentation : Dr. Amit Wasil (10 Min)
Dr. Ashish Ahuja (10 Min)
1. Spontaneous Regression of Rhegmatogenous ------------------- :
Retinal Detachmnet - A Diagnostic Dilemma

2. Intravitreal Cysticercosis - Surgical Management -------------- :

Clinical Talk :
• Management of Descemet's Membrane Detachment ----------- : Dr. Jeena Mascarenhas (15 Min)

Mini Symposium : Recent Advances

Chairman : Dr. S.C. Gupta
Co-Chairman : Dr. Anil Tara

1. Orbscan ---------------------------------------------------------------- : Dr. Ashu Agarwal (10 Min)

2. Eye Bank Specular Microscope ------------------------------------ : Dr. Jeena Mascarenhas (10 Min)

3. Pachymetry ------------------------------------------------------------ : Dr. Ashish Ahuja (10 Min.)

Discussion - 15 Min

December, 2004 191 DOS Times - Vol.10, No. 5

Letter to Editor

Dear Editor, illaries are compressed, causing impaired blood
flow. When BP falls during sleep due to noctur-
The topic of ʺAnterior Ischaemic Optic Neu- nal arterial hypotension, there may be little or no
ropathyʺ was very beautifully described in the blood flow in the ONH capillaries, resulting in
October issue of ʺDOS Timesʺ by H.S. Sethi et.al. hypoxia or ischemia of the axons. The patient dis-
I would like to add few points about AION. covers the visual loss upon waking. If the optic
disc has a large enough cup, the axons have suffi-
1) Optic disc oedema. cient space to swell without significantly com-
pressing the capillaries; thus the presence of a cup
The prevalent impression that Optic Disc is protective in mechanism. It is probable that the
Oedema in NA-AION is a ʺpale oedemaʺ is not overcrowding of the nerve fibres in a small scleral
correct. If the patient is seen at the onset ofNA- canal may be a precipitating factor in the pro-
AION, then the oedema is not pale and does not duction of NA-AION. So, one must look for size
differ from oedema due to other causes. of cup in other eye also in patients with AION.

However, if the patient is seen a couple of 3) Ocular symptoms and visual fields.
weeks after the onset, the pallor starts to develop.
Within 2-3 months, the optic disc oedema resolves NA-AION is neither a thrombotic nor an
spontaneously and is replaced by sector or gen- embolic disorder as it was thought earlier. Noc-
eralized pallor of the optic disc. But the un-in- turnal hypotension is an important risk factor for
volved part may have more oedema than the development ofNA-AION. Potent antihyperten-
ischaemic part .At this time, the involved part sive drugs when used aggressively &/or given at
has pallor but is not oedematous any more while bed time, are emerging as an important risk fac-
the rest of disc, which is normal, may show mild tor for nocturnal hypotension. There is sudden
oedema and even some pallor. and painless deterioration of vision, usually dis-
covered on waking in the morning. In eyes where
Gradually, the optic disc oedema resolves and the visual field defect bisects the fixation point,
the entire disc or only the ischaemic region may the patient may complain of intermittent blurred
show pallor, which may be more marked in the vision because of unconscious shifting between
ischaemic part. the seeing and blind areas near the fixation. When
there is progressive visual loss, the patient usu-
This evolutionary pattern of presence and se- ally notices further loss or a total loss of vision on
verity of oedema and pallor of optic disc in NA- waking in the morning.
AION results in good deal of confusion and mis-
understanding about the optic disc changes in Perimetry usually shows relative or absolute
NA-AION. So, one should remember that preva- visual field defects, which may be sectoral, alti-
lent impression about optic disc in NA-AION is tudinal, central scotoma or other optic disc re-
a ʺpale oedemaʺ is not correct. lated types. The most common visual field de-
fect in NA-AION is inferior nasal sector defect,
2) Absent or small cup in the optic disc. which may be relative or absolute; the next most
common is inferior altitudinal and/ or central
Eyes with NA-AION usually have no cup or scotoma.
only a very small cup in the optic disc. Briefly,
the ONH in the prelaminar region is surrounded Dr. Jaswant Arneja (MS)
by a firm, non-yielding Bruchsʹ membrane. Nayantara Eye Center, Delhi
When the axons swell, they can expand only at
the expense of capillaries in the ONH, so the cap-

December, 2004 192 DOS Times - Vol.10, No. 5

TRIBUTE

Dr. N.C. Singhal - A Tribute

Dr. N.C. Singhal was born in a small village in sonal experiences. He wrote books on the subject. He was
Haryana on October 6th 1922. He passed his LMP form King teacher and examiner for postgraduate students of Delhi
Edward Medical School, Indore in 1943 and obtained a and Chairman eye surgery instruments committee of In-
medal for standing first in the central province board. He dian Standard Institute ( ISI). He read papers at a number
then served in the army as a commissioned medical officer of conferences and conducted workshops. He spent his last
form 1943 to 1947 and was posted in Singapore and Burma. months compiling his experiences. His article on manage-
Passed MBBS from Lake Medical College, Calcutta in 1949. ment of recurrent pterygium has already been published
He again served with armed forces of India form 1950 to in ʺOcular Surgery News” (OSN) published from New York.
1953. Passed DOMS form Medical College, Luknow in May His articles
1954. Served in central government health scheme ( CGHS)
at Willington Hospital (now known as Ram Manohar Lohia 1. Managing small pupil in ocular surgery.
Hospital) form 1955 to 1960. He was sent on deputation to
United Kingdom by Health Ministry, Government of India 2. Simplified localization of IOFB.
for one year in 1960 for higher training under the Colombo
plan scheme. Passed FRCS, both achievements of his was 3. Simple operation for cannalicular obstruction
mentioned in the British press. Colombo plan authorities
in U.K. appreciated this and sent him on tour of 4. ‘Concept of management of macular edema in
ophthamological centers of six countries. He came back to diabetic maculopathy and CNVM”
India rich in experience and knowledge. When emergency
was declared at the time of the China war he was recalled have been accepted for publication in the same journal
by the defense ministry of India in January 1963 and spent and will be published shortly. He spent his last months
around 6 years serving the army at various command working on a book based on his personal experiences in
hospitals. Since then he has been working at Rom Manohar ocular surgery which is under publication.
Lohia and Safdarjang hospitals and has spent 17 years of
his 33 years tenure in government service and Head of He was an active member of Delhi Ophthamological
Department. He was honorary eye surgeon to the Presi- Society, Delhi Medical Association, Bharat Vikas Parishad
dent of India. He invented many new techniques to deal and Vaish Sabha.
with day to day problems like recurrent pterygium; for-
eign body removal, hidden squint etc based on his per- Dr. Singhal expired on November 20th, 2004 at the
ripe old age of 82 years. His Wife, three sons, one daughter
and many grand children survive him. His service to his
patients, the community as a whole, the medical frater-
nity and ophthalmology in particular has been immense.
He has been a source of inspiration to many budding oph-
thalmologist.

Family Members

!! Obituary !!

Dr. N.C. Singhal left for heavently abode on Saturday 20th November 2004,
at New Delhi. DOS offers deepest condolences to the grieved family members
and pray to the almighty that his soul may rest in peace.

December, 2004 193 DOS Times - Vol.10, No. 5

CURRENT PRACTICE

Transcending to Microincision Cataract Surgery (MICS)
Two Anterior Chamber Maintainers Make it Easy

Ruchi Goel MS, K.P.S. Malik, MS, MNAMS, FICS

The wound size has progressively decreased from Fig. 2: Irrigation aspiration being performed using the
12mm in intracapsular cataract surgery to 3.2mm in sleeveless I/A probe and ACM.
phacoemulsification. In phacoemulsification further reduc-
tion in size of incision is limited by the infusion sleeve. The ogy has a relatively large safety margin with regards to
sleeve cools the hand piece tip so that corneal burn does potential wound burns.
not occur. Recently, new technologies are being developed
to further decrease the size of the wound to 1.2 to 1.4mm Among the newer energy sources for phaco such as
which require sleeveless phacoemulsification tip and sepa- sonic, laser, impeller emulsification and ultrasonic energy,
rate irrigation along with chopper or second instrument. ultrasound remains the most reliable and efficient surgi-
cal technology regardless of cataract type.
Microphaco is quickly becoming the preferred method
of cataract removal because of its efficiency and safety 1. Fluidics is paramount in the performance of modern
Bimanual microincision phaco is associated with less flu- phaco. Most of the modern phacoemulsification systems
idic change throughout the eye. It also allows the incom- have antisurge mechanisms available, like the supervac
ing stream of fluid to mobilize lens fragments, and since coiled tubing and the cruise control device. Also, phacotips
there are no competing currents around the phacotip, lens with narrow throats and addition of noncompliant com-
fragments are removed more efficiently 2. ponents to phacoemulsification system has contributed to
antisurge protection.
Fig.1: Trenching being performed with the fluid inflow being
provided by the two ACMs and irrigating chopper. The problem of surge in the lower end machines can

An important factor in sleeveless phacoemulsification
is the heat generated from the ultrasound needle. The move
from continuous to pulsed ultrasound power represents a
major breakthrough in technology. A further refinement
has been to incorporate brief microbursts of energy with
independantly variable periods of rest. When the power is
off, the heat is dissipated and nuclear fragments are held
easily, ensuring a stable environment. Burst is used to de-
stroy the nucleus and rest time allows the surgeon to clear
the tissue and dissipate the heat. The microburst technol-

1. Hindu Rao Hospital, New Delhi Fig. 3 : Rollable IOL being implanted
2. VAHMC, Safdarjung Hospital, New Delhi with the help of the injector.

December, 2004 194 DOS Times - Vol.10, No. 5

be tackled by use of airpump systems and anterior cham- The capsule is stained using trypan blue dye. CCC is
ber maintainer system(ACM). The surgery can be per- performed using a cystitome through the first port. After
formed by using one/two ACMs depending on the vacuum making the chamber deep with viscoelastic, the two ACMs
settings. are inserted holding them, bevel up and rotating them in-
side the chamber to place the bevel facing the iris.
Several new Intraocular lenses are being developed Hydroprocedures are performed injecting small bolus of
that will take advantage of ultrasmall cataract incisions. fluid with intermittent tapping on the anterior surface of
The Thin-OptiX lens is a hydrophilic acrylic lens with a nucleus allowing escape of fluid. Bimanual rotation of
surface design that allows it to be rolled into a tight con- nucleus is done to check the free rotation of the nucleus
figuration that can go through a small clear corneal wound. within the capsular bag using two dialers.
Other small incision lens designs include Medennium ther-
moplastic hydrophobic acrylic IOL, which can be com- The machine settings and the nuclear cracking proce-
pressed into a thin rod insertion. Research evaluating po- dures are similar to conventional phaco-emulsification.
tential injectable polymer lenses is ongoing. The bottle height is kept at 90cm. The trenching is per-
formed using the sleeveless phaco tip, with the fluid in-
Transition to Bimanual Microincision flow through the irrigating chopper and the two ACMs
Phacoemulsification (Figure 1). The cooling of the phacotip is accomplished by
instillation of BSS on the phacotip by the assistant. After
During the learning curve, a surgeon may experience a the trenching is complete the nucleus is divided and
difference in surgical circumstances as follows: vaccuum is increased according to the grade of the nucleus.
1. Continuous curvilinear capsulorhexis is performed The stop and chop technique is used and increase in
vaccuum to even 200mm of Hg does not cause the chamber
through a small wound. One has to use either a to collapse. The cortex is removed either using sleeveless
microforceps or capsulotomy needle. Irrigation aspiration handpiece or olive tipped cannula.
The I/A probe only performs aspiration and irrigation is
2. Hydroprocedures will create sudden rise in intraocular provided by the ACM (Figure 2). Similar results are also
pressure. Surgeons may prevent this by inserting the obtained with the olive tipped cannula where a manual
irrigation cannula through the sideport and leaving it aspiration is performed. A bimanual approach allows effi-
in place during fluid injection. cient removal of the subincisional cortex. For IOL inser-
tion the first port is enlarged to 1.5mm. The Thin-Optix
3. The sleeveless phaco needle fits tightly with the 1.2mm IOL is loaded on the injector and injected into the capsular
incision. The fine movement of the tip during surgery bag (Figure 3). It takes some time to unfold after which the
is not as easy to maneuver as in 3mm incision. superior haptic is manipulated into the bag. All the ports
are then irrigated and hydrated.
4. The irrigating chopper is larger than the conventional
chopper. The surgeon must be careful to avoid injury Conclusion
to the intraocular structures.
The bimanual ultrasmall phacoemulsification surgery
Our Way of MICS using two ACMs and provides increased surgical control, greater stability of
Irrigating Chopper anterior chamber and rapid healing of wound inducing
minimal astigmatism.
The stabilization the anterior chamber is the major
hurdle in performing MICS/sleeveless phaco. The new Use of two ACMs, one conventional and one large bore
machines for phacoemulsification have surge control custom made allows the entire procedure to be accom-
mechanisms. In the second generation machines, chamber plished without any instance of chamber collapse in all
maintenance is a difficult proposition. We have overcome grades of cataract ensuring endothelial safety even with
this flaw by keeping the chamber deep using two ACMs, second generation machines.
one specially designed with 1.2mm bore and one routine
ACM . The third source of fluid is provided by the irrigat- References
ing chopper which is connected to the irrigation tube of
the phaco machine on continuous irrigation mode. Anaes- 1. Black DA Microphaco procedures. Ocular surgery News Europe/
thesia used can be peribulbar or topical. 4 clear corneal Asia-Pacific edition; March 2004, 11-12.
valvular incisions are created, first for sleeveless phaco
probe and second for the 21G irrigating chopper. The third 2. Fine H At issue: Fluidics and Cataract surgery: Ocular surgery
and the fourth ports are created at 5 o’clock and 7 o’clock news Europe/Asia Pacific Edition; August 2004, 16-17.
positions for ACM entry. The routine ACM with 0.9mm
bore is fixed nasally and the wider, 1.2mm bore custom 3. Soscia W, Howard JG, Olson RJ. Microphacoemulsification with
made ACM is placed temporally. The first two incisions White Staar: A wound temperature study. J Cataract Refract Surg
are created using 1.2mm disposable knife. The third and 2002;28:1044-1046.
the fourth ports are made using a MVR knife and 1.2mm
knife for the nasal and temporal ports respectively. 4. Soscia W, Howard JG, Olson RJ. Bimanual phacoemulsification
through 2 stab incisions-A wound temperature study. J Cataract
Refract Surg 2002; 28: 1039-1043.

December, 2004 195 DOS Times - Vol.10, No. 5

Annual Conference of

DELHI OPHTHALMOLOGICAL SOCIETY

2nd & 3rd APRIL, 2005

* ABSTRACT SUBMISSION FORM

To be sent to: Dr. Jeewan S. Titiyal, Organizing Secretary, # 476, 4th floor,
Dr. R. P. Centre for Ophthalmic Sciences,AIIMS,Ansari Nagar, New Delhi 110 029 (INDIA)
Deadline for submission of abstracts: 28th February, 2005
Deadline for submission of complete text: 15th March, 2005

TITLE FP Poster Video
AUTHORS
INSTITUTION
TYPE OF
PRESENTATION

INSTRUCTIONS TO AUTHORS: Abstracts should be submitted in English for publication in the Please Indicate: FP FP
Abstract Book. They should be typed in single spacing to fit the frame for camera ready copy. Each Session - I Session - II
abstract should be completed in only one frame. Place unusual abbreviations in parentheses after
the full word, the first time it appears. The text should not contain erasures or visible marks. Write the Presenters Surname:____________________ Name__________________________
title in Capitals, the name of the Authors and the Institution in small letters. Postal Address:_______________________________________________________
Format of Abstracts must be structured under following headings – Objective, Materials & Mobile:_______________________________ Tel: __________________________
Methods, Results and Conclusion. Abstract not to exceed 250 words. (Fax must be followed by Email (Must):__________________________
submission of hard copy of abstract by post). Abstract Received on:_____________________Signature :______________________

Please Note:
All Abstracts should compulsarily be accompanied by full text along with the illustrations and
photographs. An MS Word file of the same is also required on a 31/2 floppy disk.
Session - I: Dr. A.C. Agarwal Trophy Session (only for Delhi Members).
Session - II: Winner of Best Paper in this session will be awarded "Certificate of Merit".
ONLINE SUBMISSION: (Submission can also be made online through the DOS website: www.dosonline.org
Video in (CD, VHS) should be submitted along with abstracts.
Best Poster and Best Video presentation will be awarded trophy and "Certificate of Merit"

December, 2004 196 DOS Times - Vol.10, No. 5

APPLIANCES

Clinical interpretation of Retinal Nerve Fiber Layer
Analysis Using Scanning Laser Polarimetry with
Variable Corneal Compensation (GDX VCC)

Tanuj Dada, MD, Harinder S Sethi, MD, DNB, FRCS

Research has shown that a 40% loss of ganglion cells Principle of Scanning Laser Polarimetry
may result in only a 10dB visual field defect, a relatively The retinal nerve fiber layer (RNFL) is made of highly
shallow scotoma. Moreover, within the central 12 degrees
where an increased ganglion cell density results in consid- ordered parallel axon bundles. The axons contain micro-
erable redundancy, a 50% loss of cells corresponds to a 5db tubules, cylindrical intracellular organelles with diameters
defect. Although field defects on full threshold central 30°/ smaller than the wavelength of light. The highly ordered
24° are considered the gold standard for the diagnosis of (paralleled) structure of the microtubules is the source of
glaucoma; newer investigations are now available which RNFL birefringence. Birefringence is the splitting of a light
may have a role in the early diagnosis of glaucoma.A study wave by a polar material into two components. These com-
by Sommer et al found that 88% of ocular hypertensives ponents travel at different velocities which creates a rela-
who converted to glaucoma had Retinal Nerve Fiber Layer tive phase shift. The phase shift is termed retardation. The
(RNFL) defects at the time when visual field defect were amount of phase shift or retardation is proportional to the
detected with SAP . 60% of these converters had RNFL thickness of the RNFL.
defects present 6 years prior to the visual field defect.It has
also been seen that RNFL changes can occur prior to optic A scanning laser polarimeter is a confocal scanning
nerve head changes. The ocular hypertension treatment laser ophthalmoscope with an integrated ellipsometer to
study also reported an important finding related to early measure retardation. Retinal scanning laser polarimetry
glaucoma detection. In this 5 year study , of the patients (SLP) determines the RNFL thickness, point by point in the
who converted to glaucoma , 55% did not have any visual peripapillary region, by measuring the total retardation
field defect on standard automated perimetry and only
had structural changes in the optic nerve head.A study by Figure 1
Quigley et al found that RNFL changes were detected more
frequently than ONH changes in eyes that converted from in the light reflected from the retina. Polarized light passes
ocular hypertension to glaucoma. In a sample of 813 ocu- through the eye and is reflected off the retina. Because the
lar hypertensives followed for over 5 years, they found RNFL is birefringent, the two components of the polarized
that of the 37 eyes that developed abnormal visual field light are phase shifted relative to each other (retarded)
tests at the end of the 5 year period, 73% had either a RNFL (Figure 1). The amount of retardation is captured by a de-
defect initially or developed one during the follow-up. Pro- tector, and converted into thickness (in microns).
gressive RNFL atrophy was observed in 49% of the eyes, Anterior Segment Birefringence
while optic disc change was observed in only 19%. Several
other studies also found evidence that RNFL evaluation is In addition to the RNFL, the anterior segment (the cor-
more sensitive for predicting future visual field loss com- nea and lens), is birefringent. The total retardation of a
pared to ONH evaluation, and that the RNFL is a better subject’s eye is the sum of the cornea, lens, and RNFL bire-
predictor of damage than C/D ratio. Red-free RNFL pho- fringence. Compensation of anterior segment birefringence
tography has been used for study of the NFL but the sub- is necessary to isolate RNFL birefringence. The parameters
jective interpretation of the results and the practical prob- characterizing anterior segment birefringence are the axis
lems of the method, limit its usefulness.

An objective method to assess the RNFL is now avail-
able in the form of scanning laser polarimetry. The GDx
VCC is a scanning laser polarimeter that measures RNFL
thickness using polarized light.

Dr. R.P. Centre for Ophthalmic Sciences
AIIMS, New Delhi

December, 2004 197 DOS Times - Vol.10, No. 5

of birefringence and magnitude of retardation. Once these to red. Thick RNFL values are colored yellow, orange, and
values are known, the anterior segment birefringence can red while thin RNFL values are colored dark blue, light
be accurately compensated. blue, and green. The color scale follows the color spectrum
(blue to red) up to 120 microns.
Early scanning laser polarimeters (e.g., the GDx NFA
and the GDx Access), compensated for anterior segment 2. The Deviation Map reveals the location and magni-
birefringence based on fixed values for the axis and mag- tude of RNFL defects over the entire thickness map. The
nitude of the anterior segment birefringence. (magnitude Deviation Map analyzes a 128 x 128 pixel region (20° x 20°)
60nm, axis 15 degrees nasally). centered on the optic disc. To reduce variability due to
slight anatomical deviations between individuals, the
Variable Corneal Compensation (VCC) 128x128 pixel thickness map is averaged into a 32 x 32
square grid, where each square is the average of a 4 x 4
The GDx VCC measures and individually compen- pixel region (called super pixels). For each scan, the RNFL
sates for anterior segment birefringence for each eye. In thickness at each super pixel is compared to the age-
order to individually compensate for the anterior segment matched normative database, and the super pixels that
birefringence, the specific axis and magnitude of the ante- fall below the normal range are flagged by colored squares
rior segment birefringence must be known. This is deter- based on the probability of normality. Dark blue squares
mined by first imaging the eye without compensation. The represent areas where the RNFL thickness is below the
uncompensated image presents total retardation from the 5th percentile of the normative database. This means that
eye and includes retardation from the cornea, lens, and there is only a 5% probability that the RNFL thickness in
RNFL. The macular region of this image is then analyzed this area is within the normal range, determined by an
to determine the axis and magnitude of the anterior seg- age-matched comparison to the normative database. Light
ment birefringence. The macular region birefringence is blue squares represent deviation below the 2% level, yel-
uniform and symmetric due to the radial distribution of low represents deviation below 1%, and red represents
Henle’s fiber layer. However, in uncompensated scans, a deviation below .05%. The Deviation Map uses a grayscale
non-uniform retardation pattern is present in the macula fundus image of the eye as a background, and displays
due to the birefringence from the anterior segment . The abnormal grid values as colored squares over this image.
axis and magnitude values from the anterior segment can
be computed by analyzing the non-uniform retardation 3. The TSNIT Map : TSNIT stands for Temporal-Supe-
profile around the macula. The axis of the anterior seg- rior-Nasal-Inferior-Temporal and displays the RNFL thick-
ment birefringence is determined by the orientation of the ness values along the calculation circle starting tempo-
‘bow-tie’ birefringent pattern in the macula and the mag- rally and moving superiorly, nasally, inferiorly, and end-
nitude of the anterior segment birefringence is calculated ing temporally. In a normal eye the TSNIT plot follows the
by analyzing the circular profile of the birefringence in the typical ‘double hump’ pattern, with thick RNFL measures
macula according to standard equations. Once the ante- superiorly and inferiorly and thin RNFL values nasally
rior segment birefringence axis and magnitude values are and temporally. The TSNIT Graph shows the curve (or
determined, the retardation signal from the anterior seg- function) of the actual values for that eye along with a
ment can be compensated. In cases of macular pathology shaded area which represents the 95% normal range for
(eg macular oedema, SRNVM etc) there is a disrution of the that age. In a healthy eye, the TSNIT curve will fall within
Henle’s layer and this may lead to inaccurate compensa- the shaded area. When there is RNFL loss, the TSNIT curve
tion. In such cases, an alternative method is available that will fall below this shaded area, especially in the superior
accurately compensates for the anterior segment birefrin- and inferior regions. In the center of the printout at the
gence. bottom, the TSNIT graphs for both eyes are displayed to-
gether. In a healthy eye there is good symmetry between
Clinical Interpretation of the GDX VCC Printout the TSNIT graphs of the two eyes and the two curves will
overlap. However, in glaucoma, one eye often has more
For each GDX VCC scan, an age-matched comparison advanced RNFL loss and therefore the two curves will
is made to the normative database and any significant have less overlap. A dip in the curve of one eye relative to
deviations from normal limits are flagged as abnormal another is indicative of RNFL loss.
with a p value.
4. The Parameters are displayed in a table in the cen-
Quantitative RNFL evaluation is provided through ter of the printout. The TSNIT parameters are summary
four key elements of the printout : 1. Thickness Map, 2. measures based on RNFL thickness values within the cal-
Deviation Map, 3. TSNIT graph, and 4. Parameter table culation circle. These parameters are automatically com-
pared to the normative database and are quantified in
1. The Thickness Map shows the RNFL thickness in a
color-coded format. RNFL thickness is represented using a
color scale that follows the color spectrum going from blue

December, 2004 198 DOS Times - Vol.10, No. 5

terms of probability of normality. Normal parameter val- p<5% level)
ues are displayed in green, abnormal values are color-
coded based on their probability of normality. The normal values of these parameters in the Indian
population as per R.P. Centre data base (40-70 yrs) are :
The probability levels used are the same as the Devia-
tion Map: dark blue represents a 5% likelihood of being TSNIT Average = 54.8 + 4.1 (45.6-66.8) microns
normal, light blue represents the 2% level, yellow 1%, and
red 0.5%. As with the Deviation Map, red values indicate Superior Average = 66.8 + 6.7 (55.1-85) microns
the most severe RNFL defect.
Inferior Average = 62.1 + 6.6 (38.9 – 74.3) microns
The calculation circle is a fixed circle ( a fixed size band)
centered on the Optic Nerve Head (ONH). The band is 0.4 NFI = 17.2 + 6.9 (4 – 35)
mm wide, and has an outer diameter of 3.2 mm and an
inner diameter of 2.4mm. The RNFL values are underestimated with the
GDXVCC as compared to the OCT and these are values
The five TSNIT parameters are: TSNIT Average, Supe- inferred from the retinal birefringence and thus are not
rior Average, Inferior Average, TSNIT Standard Deviation the absolute values of RNFL thickness
(TSNIT SD), and Inter-eye Symmetry.
Figure 2 scan shows a glaucoma patient with an sig-
TSNIT Average: The average RNFL thickness around nificant loss of the retinal nerve fibers in the left eye as seen
the entire calculation circle. in the thickness map, the red pixels indicating significant
thinning as compared to the normal population in the de-
Superior Average: The average RNFL thickness in the viation map, the TSNIT graph depicting the curve below
superior 120° region of the calculation circle the normal shaded range, and the parameters showing
red marking and NFI = 63 (abnormal)
Inferior Average: The average RNFL thickness in the
inferior 120° region of the calculation circle Additional Diagnostic Parameters

TSNIT SD: This measure captures the modulation For an extended analysis the following parameters are
(peak to trough difference) of the double-hump pattern. A also available on this machine
normal eye will have high modulation in the double-hump
RNFL pattern, while a glaucoma eye will typically have • Symmetry - superior quadrant thickness/inferior quad-
low modulation in the double-hump pattern. rant thickness

Inter-eye Symmetry: Measures the degree of symme- • Superior ratio - superior quadrant thickness/tempo-
try between the right and left eyes by correlating the TSNIT ral quadrant thick.
functions from the two eyes. Values range from –1 to 1,
where values near one represent good symmetry. Normal • Inferior ratio - inferior quadrant thickness/temporal
eyes have good symmetry with values around 0.9. quadrant thickness

The Nerve Fiber Indicator (NFI) :The NFI is a global • Maximum modulation- thickest quadrant/ thinnest
measure based on the entire RNFL thickness map. It is quad. within image
calculated using an advanced form of neural network,
called a Support Vector Machine (SVM). It utilizes infor- • Ellipse modulation- thickest quadrant/ thinnest quad.
mation from the entire RNFL thickness map to optimize within ellipse
the discrimination between healthy and glaucomatous
eyes. The output of the NFI is a single value that ranges • Superior maximum - 1500 pixels in superior quadrant
from 1-100 and indicates the overall integrity of the RNFL.
Output values range from 1 –100, with classification based Detecting Progression of RNFL loss: Serial
on the ranges: 1-30 -> normal,31-50 -> borderline,51+ -> Analysis
abnormal.
The Serial Analysis printout (Figure 3) has five key
When do you call a scan as Abnormal elements that should be considered when assessing RNFL
change over time.Thickness Maps, Deviation Maps, Devia-
Although there is no consensus on definition of an ab- tion from Reference Maps, Parameters Tables, and TSNIT
normal scan, the following guidelines can be used: Graph.

TSNIT average, Superior average, Inferior average, Serial Analysis can compare up to four exams. The
TSNIT standard deviation, Intereye symmetry or NFI are first exam is the baseline or reference exam, and all follow-
abnormal at p <1% level up exams are compared to this baseline exam. A colored
rectangle to the left of the Thickness Map contains the date
They are considered Borderline if these are at p<5% and quality score of each exam. The same color is used in
level (In addition if NFI is > 47 at the p<1% level or >30 at the TSNIT graph to indicate which TSNIT curve corre-
sponds to which exam?

The Deviation from Reference Map displays the RNFL
difference, pixel by pixel, of the followup exam compared

December, 2004 199 DOS Times - Vol.10, No. 5

Figure 2

to the baseline exam. If the difference exceeds 20 microns at pared to the normative database while the Deviation from
any pixel, the pixel is color coded according to the legend. Reference Maps shows RNFL change over time in the same
RNFL change is color coded in 20 micron increments, where eye.The TSNIT Graph shows the TSNIT curves for all ex-
the first 20 micron change is coded dark green, a 40 micron ams. The color of the TSNIT curve corresponds to the color
change is coded light blue, 60 is dark blue The areas of of the vertical rectangle next to each exam (i.e., blue curve
RNFL change shown on the Deviation from Reference Map on the TSNIT graph corresponds with the blue rectangle
will frequently correspond to the areas of loss detected by for the second exam). The TSNIT curves are overlaid on the
the Deviation Map. However the correspondence is not shaded area representing the normal range for that age.
always exact because the Deviation Map shows loss com- RNFL loss will result in a lower TSNIT curve on the fol-

December, 2004 200 DOS Times - Vol.10, No. 5

low-up exam compared to the baseline exam. Figure 3
Advantages of GDXVCC • Early detection before standard visual field
• Easy to operate • Comparison with age matched normative data base
• Does not require pupillary dilatation
• Good reproducability Limitations
• Does not require a reference plane • Does not measure actual RNFL thickness (inferred
• Can detect glaucoma on the first exam
value)
December, 2004 • Low sensitivity and specificity for detection of pre-

perimetric glaucoma in clinical studies.

201 DOS Times - Vol.10, No. 5

• Does not differentiate true biological change from diagnosis of glaucoma. Arch Ophthalmol.1977; 95: 2149-56.
variability 6. Quigley HA. Examination of the retinal nerve fiber layer in the recog-

• No clinical studies on detection of progression using nition of early glaucomatous damage. Trans Am Ophthalmol Soc. 84:
this technology 920-66, 1986.
7. Airaksinen PJ, Drance SM, et al. Diffuse and localized nerve fiber
• Limited use in moderate/advanced glaucoma loss in glaucoma. Am J Ophthalmol.1984;98: 566-71.
8. Zhou Q, Weinreb RN. Individualized compensation of anterior seg-
• No data base from the Indian Population ment birefringence during scanning laser Polarimetry. Invest
Ophthalmol Vis Sci. 2002; 43: 2221-2228.:
• 4th machine prototype (cannot update earlier ver- 9. Morgan JE, Waldock A, Jeffery G, Cowey A. Retinal nerve fiber
sions) layer polarimetry: histological and clinical comparison. Br J
Ophthalmol.1998; 82: 684-690.
Affected by anterior and posterior segment 10. Reus NJ, Colen TP, Lemij HG. Visualization of localized retinal
pathology nerve fiber layer defects with the GDx with individualized and with
fixed compensation of anterior segment birefringence. Ophthalmol-
• Ocular surface disorders ogy 2003;110: 1512-1516.
11. Bagga H, Greenfield DS, Feuer W, Knighton RW. Scanning laser
• Macular pathology polarimetry with variable corneal compensation and optical coher-
ence tomography in normal and glaucomatous eyes. Am JOphthalmol
• Cataract and refractive surgery 2003;135: 521-529.

• Refractive errors (false positive in myopes) “An innovative opportunity has emerged
for a one year High Volume Phaco/ Retinal
• Peripapillary atrophy (scleral birefringence interferes Fellowship in England. The first six months
with RNFL measurement) will be spent in a Delhi Clinic sending/ re-
ceiving opinion on Retinal problems to/from
Conclusion : US/UK using latest Telemedicine technol-
ogy followed by next six months in England
The GDXVCC is still a technology in evolution with carrying out high quality research in Retina
several limitations and thus it cannot be used as a single and observing a very high volume phaco set-
test for early glaucoma detection. The current preferred up. This fellowship is highly suitable for can-
practice pattern is that we should not start therapy based didates who have just finished their resi-
on defects on the GDXVCC without abnormalities in the dency in Ophthalmology and are taking
visual fields. Practically this technology is to be used in PLAB/ awaiting SHO positions in UK.
conjunction with other anatomical and functional tests
and treatment started based on the risk of an individual Please apply with latest CV to
patient . An abnormality picked up on the GDXVCC helps [email protected].
the clinician by giving an early warning signal that the
patient requires a closer and more frequent follow up. It is For further enquiries contact
also very helpful in cases which are not co-operative for
visual fields or in which the visual field is repeatedly un- Mr. Gaurav Verma
reliable. Further long term studies are required before this
technology becomes accepted as a gold standard for early DV Tele-diagnosis,
detection of glaucoma and to monitor progression. 54-A Masjid Moth Ph-II,

References New Delhi-110048
Tel:011-29223228, 9810681954
1. Quigley HA, Katz J, Derick RJ, Gilbert D, Sommer A. An evalua-
tion of optic disc and nerve fiber layer examinations in monitoring
progression of early glaucoma damage. Ophthalmology 1992;99: 19-
28.

2. O’Conner DJ, Zeyen T, Caprioli, J. Comparisons of methods to
detect glaucomatous optic nerve damage. Ophthalmology 1993;100:
1498-1503.

3. Wollstein G, Garway-Heath DF, Fontana L, Hitchings RA. Identify-
ing early glaucomatous changes.Comparison between expert clinical
assessment of optic disc photographs and confocal scanning oph-
thalmoscopy. Ophthalmology2000; 107: 2272-7.

4. Sommer A, Katz J, Quigley HA, et al. Clinically detectable nerve
fiber atrophy precedes the onset of glaucomatous field loss. Arch
Ophthalmol. 1991; 109: 77-83.

5. Sommer A, Miller NR, Pollack I, et al. The nerve fiber layer in the

December, 2004 202 DOS Times - Vol.10, No. 5

CURRENT PRACTICE

Computer Vision Syndrome

Ramkishor Sah, B.Sc. (H) Ophth., Rajesh Sinha, MD, FRCS, Jeewan S. Titiyal, MD

Computer to-date has become an integral part of our be caused from such problems as focusing spasm, differ-
day-to-day working. Apart from posture related muscu- ent vision in each eye, astigmatism, hyperopia, myopia, or
loskeletal problems, working on the computer screen at excess light.
such a short distance can result in eyestrain.
Many people may consider the tiring of their eyes as
Computer Vision Syndrome is that complex of eye and the ‘eyestrain’ condition. This is most often caused by a
vision symptoms related to near work which are experi- condition known as convergence insufficiency and can be
enced during or related to computer use. Computer im- easily treated with convergence exercises of the ocular
ages are made up of tiny dots that do not give a clear image muscles.
so your eyes are forced to focus and re-focus continually.
This is one of the main reasons that computer work is so Dry Eye
straining to the eyes.
Possible explanation for dry eye is decreased blink rate
Children may react differently to CVS than adults due due to concentration on the task or a relatively limited
to their level of development. Children are likely to : range of eye movements. Although both book reading and
computer work result in significantly decreased blink rates,
• Show signs of depression. a difference between them is that computer work usually
requires a higher gaze angle, resulting in an increased rate
• Appear anxious. of tear evaporation. Since the main route of tear elimina-
tion is through evaporation and the amount of evapora-
• Stressful and argumentative. tion roughly relates to eye opening; the higher gaze angle
when viewing a computer screen results in faster tear loss.
• Display antisocial behavior (social phobia). It is also likely that the higher gaze angle results in a greater
percentage of blinks that are incomplete. It has been sug-
• Be excessively interested in computers - computers gested that incomplete blinks are not effective because the
become more important than socializing, watching tele- tear layer being replenished is ‘defective’ and not a full
vision and participating in family activities. tear layer.

• Complain of light sensitivity from sun (head bowed Office air environment is often low in humidity and
while outside or squinting). can contain contaminants. This has been noted as the cause
of ‘Sick Building Syndrome’. Additionally, the static elec-
• Be an insomniac or having difficult sleep. tricity generated by the display screen itself attracts dust
particles into the immediate area. These can also contrib-
• Find schoolwork stressful and uninteresting. ute to particulate matter entering the eyes, leading to dry
eye symptoms.
Symptoms of Computer Vision Syndrome(CVS):
Itching
Headache
Histamines are released when a person is under stress.
These can be precipitated by many forms of stress, This may be a possible explanation for itching in eyes of
including anxiety and depression; numerous eye condi- computer personnels. Another reason for itching in eyes
tions, including astigmatism and hyperopia; improper in these cases is the precipitation of dry eye due to con-
workplace conditions, including glare, poor lighting, and stant use of computers.
improper workstation setup. These types of headaches are
mild to moderate in intensity, often occur on either or both Neck and Back Pain
sides of the head, are not aggravated by physical activity,
develop during the early to mid part of the day, last from It is often heard in medical circles that ‘the eyes lead
30 minutes to the rest of the day, and are relieved by rest or the body’. Nature has made our visual system so domi-
sleep. nant that we alter our body posture to ease any deficiency
in the way we see.
Eye Strain
These situations are very common in the office envi-
Eyestrain is the most common complaint of computer ronment and cause excessive postural accommodations,
users. Eyestrain can have many meanings to people. It can

Cornea & Refractive Surgery Services
Dr. R.P. Centre for Ophthalmic Sciences
AIIMS, New Delhi - 110029

December, 2004 203 DOS Times - Vol.10, No. 5

which lead to the symptoms of neck and back discomfort. reflected in the screen and does not disturb your pe-
Several studies have found that doing computer work for ripheral vision.
about three hours contributed not only to eye muscle fa-
tigue but also muscle pain in the head, neck and upper • Limit reflections further by shading the screen with a
back regions. In normal, upright sitting posture (without file folder or purchasing an anti-reflection screen.
a visual target), studies have found that subjects tilt their
head and neck at an average of 13 degrees forward from • Clean the computer screen frequently.
the upright position. If the monitor is set to eye level, the
user is presented with a choice: either assume a more erect • Work in a large, legible font and reduce it later if neces-
head/neck posture than preferred or employ a gaze angle sary.
that is too high.
• Have your eyeglass prescription checked regularly.
There is no ‘perfect’ screen height but, in general, when Measure the distance of the screen from your eye and
sitting in your chair gazing straight ahead, you should be the angle at which you view it, and take these mea-
able to look OVER your monitor. Most monitor positions surements to the optometrist. You may need a special
are too high and that is the leading cause of neck pain. pair of glasses for computer work.

Light Sensitivity • Take hourly breaks.

Discomfort glare is largely caused by large differences • Perform convergence exercises regularly if you are a
in brightness in the field of view. It is much more desirable myope.
to eliminate bright sources of light from the field of view
and strive to obtain a relatively even distribution of light. Computer Glasses
You might be at greater risk to experience discomfort glare
when the source of glare is brighter and when it is closer to Computer eyeglasses refer to the use of bifocal “com-
the point of attention. puter glasses” to reduce eye fatigue from viewing com-
puter monitors. Many so-called computer glasses have only
Blurred Vision inexpensive tinted lenses.

It has been found that small amounts of refractive er- However, the best solution is rimless bifocal reading
ror contribute to the visual discomfort of computer users. glasses with ultra light designer rimless frames and the
Considering the working environment, blurred images can selection of lenses should be performed to match each eye’s
also arise from a dirty screen, poor viewing angle, reflected requirements. These bifocal reading glasses or “Computer
glare or a poor quality or defective monitor. All of these Glasses” represent the best practical solution to eye strain
factors should be considered when this symptom occurs. resulting from computer monitor use. These computer eye-
glasses should have optical CR39 lenses with anti-reflec-
A condition known as ‘transient’ myopia has been tive coatings.
shown to be more prevalent in a population of computer
users. Research has found that 20% of computer workers Reading Glasses as Computer Glasses
had a nearsighted tendency toward the end of their work
shift. Reading glasses are not suitable for most computer
users as you cannot choose individual eye strengths and
Prevention of Computer Vision Syndrome the interpupillary distance can be quite far off (one size fits
all) thus inducing “prism” and causing additional eye-
Computer vision syndrome is the term given for the strain.
group of symptoms that can arise from hours of working
at a computer. They include eyestrain, headache, blurry Progressive Lenses for Computer Glasses
near vision, slowness in changing focus, light sensitivity,
eye irritation, and pain in the neck, shoulder and back. Progressive lenses are often prescribed for use in Com-
puter Eye Glasses.
There are some things you can do to prevent or correct
these problems: Aside from costing more than normal lenses these re-
quire very careful prescriptions and fitting of the eyeglasses
• Position the screen 4-9 inches below eye level so that for comfortable wear after an adjustment period. They are
you gaze downward and prevent neck strain. Adjust not suitable for “made to wear” computer glasses and af-
your chair accordingly. ter reading complaints from consumers unhappy with
progressives, we feel a conventional “line bifocal” is more
• Locate the monitor right in front of you, 20-28 inches appropriate for computer glasses.
from the eyes.
With a few simple changes, the environmental causes
• If you’re consulting a document, position it the same of CVS can be easily eliminated. Some solutions to these
distance from you as the screen. environmental causes include:

• Limit glare by positioning lamps so that light is not • Reducing glare and harsh reflections on the computer
screen by modifying the lighting in the room, closing
window shades, changing the contrast or brightness
of the screen, or attaching a filter or hood to the moni-

December, 2004 204 DOS Times - Vol.10, No. 5

tor. Position your computer so that any windows are muscles, but will also give the eyes a chance to relax. If

to the side of the monitor, rather in front or in back. the opportunity to get up for full breaks is not fre-

• Adjust window blinds so that the sunlight is away quently available, then “mini” breaks will suffice by

from your screen and your eyes. looking up from the computer into the distance about

• Turn off overhead lights that are too bright. If this turns every 15 minutes. Frequent blinking or the use of eye
out to be not bright enough, switch to a lower wattage drops, too, will keep eyes from drying out and feeling
bulb, or use a desk lamp. itchy.

• Move your desk lamp to a spot where it doesn’t reflect • Finding and improving other problems that may be
on the screen or shine in your eyes. affecting the eyes, including drafty, dry or dusty air.
Try to keep air vents or drafts from blowing into the
• Attach a glare-blocking hood to your monitor. Much
face and drying out the eyes. Low humidity or fumes
as a jacket hood can reduce the amount of sunlight
in a room can also dry eyes out faster than usual. Dust,
that reaches your eyes from the top and sides of your
too, can irritate eyes as well as accumulate on the com-
head, a monitor hood reduces the amount of light that
puter monitor, which will decrease the sharpness of
can reach your screen.
the screen and may cause eyestrain.

• Attach a glare filter to your screen. Filters are readily The basics of computer ergonomics
available from office supply stores, but you may need
There are some of the ergonomic guidelines for the vi-
to look online to find a hood for your computer. Less
common sources of glare and reflection are office walls sual comfort of desktop users.

and desks, particularly bright white. Think about a • Working distance from eye to screen should be set be-

paint job or a new desk if you find these surfaces to be tween 20ʺ and 26ʺ.

giving you trouble. • Viewing angle for the screen should be 10 degrees to

• The computer screen should be at or just beyond an 15 degrees below straight-ahead gaze position. That

arm’s length away (about 20 to 26 inches) to give eyes would be equivalent to about a 10ʺ drop from the

a comfortable focusing distance. The screen should also straight-ahead gaze line directly above the screen to

stand straight in front of the face instead of off to the the center of the screen.

side to ease eyestrain. The center of the monitor should • Room lighting should be free of glare sources as much
be about four to eight inches lower than the eyes to
as possible. Screen anti-glare cover filters should be
allow the neck to relax and to lessen the exposed sur-
used where necessary (glass filters only; do not use
face area of the eye, which will reduce dryness and
plastic mesh filters).
itching.
• Cover or mask windows to prevent glare from sun-
• Placing reference materials as close to the screen as
light, and place computer screens at 90 degrees angles
possible. This will lessen the need to constantly refo-
to windows whenever possible.
cus the eyes as well as the need to swing the head back • Reduce room lighting so that screen brightness and
and forth between the materials and the monitor. Us-
contrast can also be reduced to more comfortable lev-
ing a document holder beside the monitor will mini-
mize head and eye movements and focusing changes, els. Use task lighting at each desk to illuminate copy
work.
and will decrease muscle fatigue, headaches and eye
Sharing these guidelines with your patients will again
strain.
boost your credibility and strengthen your reputation as
• Improving posture by using adjustable equipment to an expert in CVS vision care.
reduce strain on the back, neck, shoulders and eyes.

Adjust the height of the chair so the knees are bent at a

90-degree angle with the feet flat on the floor or foot- Table 1: Summary of Steps for Preventing CVS
rest. Sit straight against a back rest with the forearms • Use good quality monitor
on armrests and the elbows bent at a 90-degree angle. • Set resolution high
The keyboard and mouse should be located lower than • Make an effort to blink your eyes more often
the elbow and within easy reach of the hands. The • Ensure proper lighting at your workstation
head should be tilted slightly down while looking at • Don’t have you or screen facing a window
the center of the computer screen. • Eliminate any sources of glare in the office

• Giving the eyes and body frequent breaks from com- • Angle your computer slightly below eye level
puter work to reduce eye and muscle fatigue. Since
prolonged computer use requires a person to sit in the • Position your monitor 50 to 60 cm away from your
same position for an extended period, taking time out eyes
to stand, stretch and look around will not only help
• See your eye-care specialist for an eye checkup to
determine if you need computer glasses

December, 2004 205 DOS Times - Vol.10, No. 5

CURRENT PRACTICE

Diabetic Macular Edema: Recent Treatment Modalities

Mohita Sharma MS, Angshuman Goswami MS, DNB

Diabetic macular edema is the most common cause of patients develop CNVM despite receiving apparently mild
moderate visual loss in patients with diabetes. Macular laser burns. Additional complications that can occur fol-
edema results from the breakdown of the blood-retinal lowing laser photocoagulation in patients with diabetic
barrier in the retinal capillaries. The tight endothelial cell macular edema include subretinal fibrosis, foveal distor-
junctions break down resulting in increased vascular per- tion, accidental foveal burns, decreased contrast sensitiv-
meability and increased fluid accumulation in the outer ity, blood vessel perforation, and the formation of
layers of the retina. Microaneurysms are believed to play chorioretinal anastomosis. Studies have also shown the
a significant role by acting as sources for fluid and lipid role of both subthreshold micropulse diode (810nm) as well
transudation. Factors that are believed to cause the for- as ND: YLF laser (527nm) in the treatment of diabetic macu-
mation of microaneurysms are loss of pericytes and sup- lar edema1 .
porting astrocytes in the retina, increased capillary trans-
mural pressure, and local production of vasoproliferative Continuous wave vs micropulse laser
factors such as vascular endothelial growth factor (VEGF).
Hyperglycemia is believed to be the main factor that causes The current technique of focal laser photocoagulation
increased oxidative stress and diacylglycerol accumula- for CSME causes moderate whitening of the RPE-outer
tion. This substance activates protein kinase C which in retina. Power sufficient to create mild whitening at the
turn increases VEGF expression. level of the RPE-outer retina is generally accepted as the
threshold intensity for treatment. This treatment inten-
The efficacy of laser treatment for diabetic macular sity is associated with heat-induced damage to the photo-
edema has been documented in the ETDRS trial. Some cases receptors and choriocapillaris.The currently used continu-
of diabetic macular edema either do not respond to laser ous wave (cw) laser system cannot limit the treatment
photocoagulation or show a limited response or are recal- solely to the RPE with the required exposure time of 50-
citrant. These observations have led to the search for other 100 milliseconds (ms). The heat generated from the laser
new approaches for the treatment of diabetic macular diffuses into the adjacent tissue. This area of heat damage,
edema, both primary cases and those not responding to called the thermal diffusion area, decreases as the pulse
laser photocoagulation. These include newer type of laser duration decreases. In fact, the treatment can be confined
treatments, a number of pharmacologic agents as well as predominantly to the RPE if the laser exposure time is de-
surgical treatments. creased to 1 ms. Hence, laser pulses of very short duration
will affect the RPE alone with little effect on the photore-
Subthreshold (Invisible) Micropulse Grid Laser

Micropulse subthreshold diode laser (810 nm) therapy,
which has been shown to be effective in diabetic macular
edema, is emerging as an alternative form of laser therapy
owing to its significant advantages over conventional reti-
nal laser photocoagulation since it is theoretically less likely
to produce unwanted retinal or choroidal thermal dam-
age. Conventional laser treatment can be associated with
complications, such as the formation of permanent
scotomata.Scotomata may or may not be clinically signifi-
cant depending on the number of burns, their size and
their proximity to the edge of the foveal avascular zone.
Occasionally, laser burns are associated with the develop-
ment of choroidal neovascularization, which is often diffi-
cult to treat and can itself cause severe visual loss. Many
clinicians suspect that laser-induced CNVM is more likely
when particularly intense laser burns are applied during
treatment. Still, the clinical response to conventional laser
photocoagulation for CSME is variable, and some diabetic

Tirupati Eye Centre,
C-8, Sector - 19, Noida - 201301

December, 2004 206 DOS Times - Vol.10, No. 5

ceptors or choriocapillaris2(Figure 1). stroying the photoreceptors in order to achieve a thera-
peutic effect. Further experimental and controlled clinical
The diameter of a RPE cell is ~10 µm. Pulse duration of trials are being carried out to clarify the value of this type
0.1 ms (termed micropulse) corresponds to a thermal dif- of photocoagulation.
fusion distance of 10 µm in ocular tissue. Thus, pulse dura-
tion of less than 0.1 ms should have no thermal effect on Intravitreal Triamcinolone Acetonide
structures 10 µm or more from the RPE cell (e.g., photore-
ceptors and choroidal melanin granules) and may be asso- The exact mechanism of action of intravitreal triamci-
ciated with a lower incidence of complications such as nolone in the treatment of macular edema is unknown.
symptomatic scotomata and CNV formation. The increase However, the rationale behind its use lies in its ability to
in initial edema induced by laser is more pronounced with inhibit the arachidonic acid pathway, of which prostag-
suprathreshold grid than with subthreshold grid, whereas landin is a product. Triamcinolone may also downregulate
after 1 month, an appreciable reduction in edema is the production of vascular endothelial growth factor
achieved with both protocols3.The subthreshold grid is (VEGF). Finally, triamcinolone acetonide has been shown
executed according to the Akduman and Olk protocol4. First experimentally to reduce the breakdown of the blood-reti-
the laser impact is tested with a 125 micron spot,200ms nal barrier.
duration and power adjusted to produce a barely percep-
tible reaction; then the grid treatment is executed using Procedure
the same spot and power, but halving the duration to 100
ms(50% of the energy used for the test impact).Clinical Early studies with intravitreal triamcinolone in the
studies suggest that subthreshold micropulse diode laser treatment of recalcitrant macular edema have demon-
photocoagulation (SMDLP) induces resolution of macular strated good results (7, 8) .Eyes are considered to have re-
edema. One such study compared the effectiveness of sub- calcitrant macular edema when two prior sessions of grid
threshold micropulse diode laser and the conventional or focal photocoagulation fail. 4.0 mg/0.1 ml of Triamcino-
argon laser and both showed an equally good effect on lone acetonide is injected intravitreally under topical an-
stabilization of visual acuity. As treatment applications in esthesia 4.0 mm from the limbus. A 26-G needle is gener-
subthreshold micropulse mode are invisible, a clear treat- ally recommended to prevent clogging by suspended par-
ment plan is demanded. Recently indocyanine green an- ticles. Best corrected visual acuity is measured at each ex-
giography has been shown to precisely localize subthresh- amination. In addition the central macular thickness can
old infrared laser photocoagulation sites immediately af- be quantitatively measured by optical coherence tomog-
ter treatment5. raphy (OCT) examination at each visit. The amount of hard
exudates deposition in the macula can be subjectively
Subthreshold (invisible) diode laser modified grid evaluated using colour fundus photographs.
photocoagulation is effective in reducing/eliminating dia-
betic macular edema, although resolution of edema may Studies
be slightly prolonged. However, this method may be ad-
vantageous in that it appears to reduce the objective and Martidis et. al. recently reported on the use of
subjective effect on the paracentral visual field. Subthresh- intravitreal triamcinolone in the dose of 4 mg in 0.1 ml for
old (invisible) diode laser modified grid photocoagulation the treatment of refractory diabetic macular edema6. They
substantially reduces the post-treatment atrophic scar- found an improvement in visual acuity with decrease in
ring. central macular thickness as measured by OCT. Intraocu-
lar pressure exceeded 21 mm Hg in five eyes. One eye ex-
The subtle nature of subthreshold photocoagulation hibited cataract progression at 6 months. Re-injection was
shows that these laser burns are different from the stan- performed after 6 months in three of eight eyes (37%), be-
dard laser photocoagulation regime. All laser exposures, cause of recurrence of diabetic macular edema.
which produce RPE disruption, are detectable only by FA
and are not visible by ophthamoscopy during or 2 years Jonas et. al. reported similar results with the use of
after photocoagulation. The main problem of this technique intravitreal triamcinolone in the dose of 25 mg in 0.2 ml in
is related to dosimetry. Unclear variables are appropriate diabetic patients with diffuse macular edema.They found
laser energy, necessary number of laser burns, and indi- that the positive effect of triamcinolone reaches its maxi-
vidual RPE reaction. Theoretical considerations and early mum at 1-3 months. Repeated intravitreal triamcinolone
clinical results indicate, however, that micropulse laser treatment is generally required.
may offer an effective and safer treatment option for pa-
tients with this very common cause of visual disability. Ciardella et. al. used intravitreal triamcinolone
Clinical findings suggest that in some diseases it is not acetonide in patients of recalcitrant macular edema. They
always necessary to produce retinal blanching and de- did not experience any major complications. No case of
infectious endophthalmitis occurred in this series. How-
ever, infectious and non-infectious endophthalmitis is a
potential serious complication of intravitreal triamcino-

December, 2004 207 DOS Times - Vol.10, No. 5

Centre spread

December, 2004 208 DOS Times - Vol.10, No. 5

Centre spread

December, 2004 209 DOS Times - Vol.10, No. 5

lone. Intraocular pressure rose above 21 mm Hg in 12 (40%) the progression of diabetic retinopathy including
of 30 eyes. In all cases in this study, the increase in IOP was maculopathy. A clinical trial on this medication does not
controlled with topical antiglaucoma medications. Sub- yet have enough data to make a general recommendation
capsular cataract formation has also been reported as a to change current management strategies with laser sur-
complication of intravitreal triamcinolone. gery or pars plana vitrectomy. Similarly, Genetech is cur-
rently testing Anti-Vascular Endothelial Growth Factors
Intravitreal triamcinolone is a promising therapy for (anti-VEGF) drugs for wet age-related macular degenera-
patients with diabetic macular edema refractory to laser tion. These anti-VEGF drugs may have future application
treatment. It is effective in improving vision, reducing for the treatment of diabetic retinopathy and maculopathy.
macular thickness, and inducing reabsorption of hard exu-
dates. Further investigation is warranted to assess its effi- Supplemental Oxygen
cacy and safety.
Doctors at John Hopkins have discovered a new
Drug Delivery Insert therapy that may breathe new life into some damaged
eyes. By giving patients with diabetic macular edema
Control Delivery Systems, along with Bausch and supplemental oxygen where they simply breathe higher
Lomb, have developed a tiny implantable device called levels of oxygen in, they have seen a decrease in thickening
the Envision TD implant designed to treat problems in the in the retina and some improvement in visual acuity. Pa-
back of the eye. The implant is surgically placed inside the tients in the study have been given oxygen tanks to use 24
eye and gradually releases medication over a long period hours a day for 3 months. The added oxygen they breathe
of time. This technology has already been used to treat in goes to the retina. This helps thin the retina, which im-
CMV retinitis, a complication of AIDS. The Envision TD proves vision. Patients in the study have been provided
implant is currently being studied for the treatment of with a stationary oxygen concentrator for home and por-
diabetic macular edema (DME).Just a few millimeters in table oxygen tanks to use outside the home.
length, the implant contains a steroid called fluocinolone,
which is slowly and consistently delivered to the macula. Surgical Treatment-Pars Plana Vitrectomy
The technology is unique because it treats the disease while
avoiding many side affects of the drug. Encouraging study A taut posterior hyaloid attached on and around the
results have already been reported. macula causing traction over the retina has been impli-
cated as one cause of chronic diabetic macular edema non
Macugen(TM) responsive to laser photocoagulation. It has been advised
that in such cases surgical treatment by way of vitrectomy
Phase 2 study of Macugen, an investigational drug ensuring removal of the posterior hyaloid internal limit-
has shown positive visual and anatomical outcomes for ing membrane (ILM) peeling can be attempted. The reported
diabetic macular edema. The preliminary data were sta- success rate is about 68% excluding cases with severe exu-
tistically significant for Macugen (0.3 mg) vs sham injec- dative maculopathy. Such surgeries have been found to be
tion. Patients received varying doses (0.3 mg, 1 mg, 3 mg) associated with a significant improvement in visual acu-
of Macugen via intravitreal injections or sham every six ity and diminution of retinal thickness as measured by
weeks for at least 12 weeks. The patients enrolled in this OCT.
study were required to have been eligible for thermal laser
therapy for diabetic macular edema. In the Macugen (0.3 References
mg) group, 73% of patients gained 0 or more lines com-
pared to 51% in the sham injected group, 59% of patients (1) Johann Roider, Ralf Brinkmann, Christopher Wirbelauer, Horst
gained 1 or more lines, 34% of patients gained 2 or more Laqua, Reginald Birngruber. Subthreshold (retinal pigment epithe-
lines, 18% of patients gained 3 or more lines.OCT showed a lium) photocoagulation in macular diseases: a pilot study. Br J
300% relative reduction trend in retinal thickness for Ophthalmol 2000; 84:40-47
Macugen (0.3 mg) compared to controls. A preliminary
look at the data suggests that the safety profile of Macugen (2) Campochiaro PA, Hackett SF, Vinores SA, et al: Platelet- derived
in patients with diabetic macular edema appears to be growth factor is an autocrine growth stimulator in retinal pigmented
well-tolerated. Further detailed analysis of the safety data epithelial cells Cell Sci 1994; 107:2479-2469
is ongoing. Most of the adverse events appear mild, tran-
sient. (3) Gaetano Russo. Suprathreshold and subthreshold treatment of
macular edema. Ophthalmic Surg. Lasers 1999; 30:706-714
Protein kinase c-beta inhibitor
(4) Olk RJ, Friberg TR, Stickney KL, et al. Therapeutic benefits of
Two new medications are currently being investigated infrared (810 nm) diode laser macular grid photocoagulation in pro-
for diabetic retinopathy. LY333531,a protein Kinase C-beta phylactic treatment of nonexecutive age related macular degenera-
inhibitor (PKC-beta inhibitor) developed by Eli Lilly and tion. Ophthalmology 1999; 106:2082-2090
Company, is a promising new medication for preventing
(5) Laursen ML, Moeller F, Sander B, Joelie AK. Subthreshold
micropulse diode laser treatment in diabetic macular edema. Br. J
Ophthalmol 2004; 88:1173-1179

(6) Martidis A, Duker JS, Greenberg PB, Rogers AH, Puliafito CA,
Reichel E, Baumal C. Intravitreal triamcinolone for refractory dia-
betic macular edema. Ophthalmology 2002 May; 109(5):920-7

December, 2004 210 DOS Times - Vol.10, No. 5

CURRENT PRACTICE

Emerging Treatment Modalities in Diabetic Eye Disease

Parul Sony MD, Pradeep Venkatesh MD, Sat Pal Garg MD

Diabetes Mellitus is one of the leading causes of blind- PKC beta inhibitors
ness in whole world. Diabetic macular edema and sequelae
of diabetic retinopathy are the major cause vision loss in Ruboxistaurin Mesylate is oral selective PKC beta in-
these patients. The present treatment of these cases focuses hibitor, which has been shown to delay the progression of
on blood sugar control, intervention with laser applica- diabetic retinopathy. Two trials have evaluated the role of
tion (practiced as per guidelines laid by ETDRS study and PKC beta inhibitors in diabetic retinopathy; Protein ki-
DRS study), and surgical intervention in form of pars-plana nase C inhibitor diabetic retinopathy study (PKC-DRS) and
vitrectomy and vitreoretinal surgery whenever indicated. Protein kinase C inhibitor diabetic macular edema study
None of the available treatment modalities promise a 100% (PKC-DMES).
success in controlling the further progression of disease
process. PKC-DRS was multi-centric, double blind trial with
252 patients of severe to very severe NPDR, with a BCVA
This article discussed various newer modalities that of 20/125 or better and no prior laser treatment. Patients
are being evaluated for the treatment of diabetic retinopa- received 8mg, 16mg and 32 mg of drug orally. A 42 months
thy. follow-up showed a 32% reduction in the risk of progres-
sion of 2 steps or more on ETDRS scale.
Vascular endothelial growth factors (VEGF)
PKC-DMES enrolled 686 patients with diabetic macu-
VEGF is produced by glial cells, retinal pigment epi- lar edema, BCVA 20/25 or better and no prior laser treat-
thelium (RPE) cells and is normally present in retina and ment. At 36 months follow-up all the patients excluding
vitreous in low levels. Its production is upregulated in pres- the patients with poor glycemic control showed a reduc-
ence of retinal hypoxia. Increased levels of VEGF contrib- tion in progression of diabetic macular edema.
ute to increase vascular permeability and abnormal
angiogensis. Flucinolone acetonide implant

Protein Kinase C (PKC) This implant consists of a drug pellet and is 2 X 2 X
6mm in size and releases flucinolone at a constant rate
PKC is a group of enzymes that play important role in over a three-year period. A multi-centric, masked, ran-
signaling the production of VEGF thus altering the vascu- domized controlled trial evaluating the effect of flucinolone
lar permeability. Uncontrolled diabetics have high levels implant on 80 patients of diabetic macular edema, BCVA
of diacylglycerol, which in turn activates the beta isoform of >20/400 and less than 20/50, with a history of one epi-
of PKC. sode of laser treatment 3 months back showed complete
resolution of macular edema in 54% of eyes with implant
Both VEGF inhibitors and PKC inhibitors have been compared to the control group at 24 months along with
shown to influence the development of vascular complica- decrease in retinal thickness in 46 % of treatment groups
tions in diabetic patients. compared to 15% in control group. The main side effects
noted during the study were increased IOP in 32% and
VEGF inhibitors increased incidence of cataract in the implanted eyes.

Macugen (pegaptanib sodium) is VEGF inhibitor, which Intravitreal triamcinolone
selectively blocks VEGF 165 isofom, is given intravitreally
(0.3, 1, 3 mg dosages). Preliminary results of a multicentric Use of intravitreal triamcinolone for treatment of re-
randomized trial using Macugen have shown its benefi- fractory diffuse diabetic macular edema is gaining popu-
cial effect in improving the visual acuity and reducing the larity. Intravitreal steroid injection study (ISIS) is a pro-
macular thickness on OCT. This study has shown a 2 or spective multicentric trial evaluating the role of 2 and 4mg
more line improvement in 34% in treatment group Vs 10% triamcinolone acetonide in macular edema secondary to
in placebo group at 36 weeks. The drug is well tolerated diabetes (33 patients), retinal vein occlusion, pseudophakia
however the effect of drug is transient and remains for 6 and retinal telangectasia. Six months results of the study
weeks thus requiring repeat injections. showed that intravitreal triamcinolone is effective in im-
proving the visual acuity in patients with refractory DME.
Dr. Rajendra Prasad Centre for Ophthalmic Sciences,
All India Institute of Medical Sciences, Transient IOP elevation, cataract, pesudoend-
New Delhi - 110029 ophthalmitis are the few complications of this treatment

December, 2004 211 DOS Times - Vol.10, No. 5

modality. Infectious endophthalmitis is the most serious Most of the above mentioned treatment modalities
complication following intravitreal triamcinolone injec- have shown encouraging results in the initial trails. How-
tion. ever till date they are used as adjuncts to the standard
laser treatment. Long term comparative safety and effi-
Vitrase cacy trials comparing the newer treatments with the con-
ventional laser treatment are needed to establish their
Vitrase is a highly purified preservative free ovine hy- exact role.
aluronidase approved by FDA for intravitreal use. It facili-
tates dispersion and absorption of other drugs. It can be Suggested Readings
used for treatment of non-resolving vitreous hemorrhage.
Vitrase for vitreous hemorrhage study was a randomized 1. Milton RC, Aiello LP, Davis MD et al. Initial results of the protein
double masked controlled study designed to evaluate safety kinase beta inhibitor diabetic retinpathy study. Diabetologica
and efficacy of vitrase (50mL, 55mL, 75mL) in treatment of 2003;46:A42.
vitreous hemorrhage. At 3 months a 43% (55mL) and 39%
(75mL) reduction in density of vitreous hemorrhage com- 2. Aiello LP, Davis MD, Milton RC et al. Initial results of the protein
pared to the control group. The main adverse events noted kinase beta inhibitor diabetic macular edema study. Diabetologica
were mild iritis, hyperemia, lacrimation and photopho- 2003;46:A42.
bia.

Invitation for Upgradation of
Group Practice
Vitreoretinal Faculty
To Join 19yr. Ophthalmic practice of
Dr. Sharad Lakhotia Dr. Jayant Guha, Senior Vitreo-
Retinal Surgeon, under the auspices
Lakhotia Eye Centre of Sai Retina Foundation (Basement
of Navjyoti Eye Centre, 90 Darya
& Ganj) / upgraded Vitreoretinal
facilities with Alcon® Accurus
Laser Institute Advanced Vitrectomy System with
Phaco fragmetome
E-544, Greater Kailash-II,
New Delhi-110048 • Unique Direct Venturi System (High
performance Fluidics)
Mobile : 3912255311 / 9810236265
• High Speed pneumatic cutters (2500
At one of the most sophisticated & posh cpm)
area of Delhi. Also to join Hospital at Sector
- 37, Faridabad at Delhi border. A • Automated VGFI (Vented Gas Forced
vitreoretinal Surgeon with or without Infusion)
investment is preferred. Visionary
Ophthalmologist with aim of long- term • Automated VFC (Silicon Oil Injection)
association may also join for a mega
project. • Grieshaber Light Source (Industry Gold
Standard)

and Transpupillary Thermo Therapy with
IRIS Oculight 810 nm Diode Laser.

December, 2004 212 DOS Times - Vol.10, No. 5

JOURNAL ABSTRACTS

Conductive keratoplasty good option for varying central corneal thickness (CCT) due to
the treatment of presbyopia?: A six- penetrating keratoplasty (PK), keratoconus (KC), and
month results of the 1-year United States Fuchs’ endothelial dystrophy (FED). IOP was
FDA clinical trial measured with the Goldmann applanation
tonometer, Tono-Pen XL, and OBF
McDonald MB, Durrie D, Asbell P, Maloney R, pneumotonometer in 127 eyes with the following
Nichamin L. Cornea. 2004 Oct; 23(7): 661-8 corneal abnormalities. There were 56 eyes that had
undergone PK, 37 eyes with KC, and 34 eyes with
A total of 143 patients with presbyopic symptoms FED. CCT was measured using an ultrasound
were enrolled in this 1-year United States FDA clinical pachymeter after IOP determinations had been
trial and treated to improve near vision in 1 eye made.
(unilateral treatment). In addition, 33 fellow eyes
were treated to improve distance vision (bilateral The Results showed, the mean IOP
treatment). For near vision correction, the target measurements in all three patient groups were
refraction was up to -2.0 D in the nondominant eye, significantly higher when measured by OBF
and for distance vision correction, 0.0 D. Enrolled pneumotonometer. Linearregression analysis showed
patients had a preoperative spherical equivalent of that patients with FED had a significant increase in
plano to +2.00 D, no more than 0.75 D of refractive IOP with increasing CCT of 0.18 mm Hg/10 µm using
astigmatism, and were 40 years of age or older. No the Goldmann tonometer, 0.15 mm Hg/10 µm with
retreatments were performed. Results showed of the the Tono-Pen, and 0.26 mm Hg/10 µm with the OBF
eyes treated for near, 77% had uncorrected near pneumotonometer. In patients with KC and after PK,
vision of J3 or better at 6 months postoperatively. A linear regression analysis did not show a significant
total of 85% of all patients had binocular distance effect of CCT on IOP. A multivariate linear regression
UCVA of 20/25 or better along with J3 or better near, model controlling for age, sex, graft size, and patient
a combination that represents functional acuity for group, showed that the effect of CCT on IOP for
a presbyope. Sixty-six percent of eyes treated for near Tono-Pen (0.13 mm Hg/10 µm CCT) and Goldmann
had a manifest refractive spherical equivalent (MRSE) (0.14 mm Hg/10 µm CCT) were significantly lower
within +/- 0.50 D of intended at 6 months. In 89% of than for the OBF pneumotonometer (0.26 mm Hg/
eyes, the MRSE changed 0.05 D or less between 3 10 µm CCT).
and 6 months postoperatively. After month 1, the
incidence of variables associated with safety was 1% This study concludes that mean IOP
or lower. Seventy-six percent were very satisfied or measurements using the OBF pneumotonometer
satisfied with their procedure. The study concludes, were significantly higher than those made using the
Conductive Keratoplasty appears to be very safe and Goldmann applanation tonometer or Tono-Pen in
effective in producing functional visual acuity in eyes with a variety of cornel pathologies. The OBF
presbyopic eyes up to 6 months following the pneumotonometer was found to be most affected by
procedure. Patient satisfaction with the procedure is variation in CCT. For all three instruments, the
similar to that of monovision LASIK. relation between IOP and CCT depended on the
corneal pathology and was greatest for FED.
The effect of corneal thickness on IOP
measurement in patients with corneal Mitomycin C for pterygium: long term
pathology evaluation

A C Browning, A Bhan, A P Rotchford, S Shah and F Raiskup, A Solomon, D Landau, M Ilsar and J Frucht-
H S Dua. British J Ophthalmol 2004; 88:1395-1399 Pery British J Ophthalmol 2004;88:1425-1428

The aim of the study was to compare intraocular A prospective non-comparative interventional
pressure (IOP) measurements taken by the case series to evaluate long term complications after
Goldmann applanation tonometer, the Tono-Pen and pterygium excision with mitomycin C (MMC)
the ocular blood flow pneumotonometer in eyes with application.99 patients who underwent pterygium
surgery and participated in a controlled study for

December, 2004 213 DOS Times - Vol.10, No. 5

efficacy of MMC for pterygium surgery between myocysticerci in lateral and one in inferior recti
1989 and 1994. The bare sclera area, in particular, muscles, mechanically indenting the eyeball, causing
was examined for possible complications. The main scleral indentation, evidenced by ultrasonography
outcome measures were anatomical findings in area or computed tomography. Associated signs of
of MMC application. Forty three eyes of 43 patients myocysticercosis were orbital inflammation,
were examined. Sixty three per cent of patients had restricted ocular motility or proptosis. In 2 to 10 days,
pterygium surgery with intraoperative application of the cysts traveled forward and came to lie in a sub-
0.02% MMC for 5 minutes and 37% of patients Tenon position. Three cysts were removed surgically
received MMC 1% or 2% drops four times daily for and one extruded spontaneously. They conclude
2 weeks postoperatively. In three patients, pterygium patients presenting with a clinical picture similar to
recurred within 18 months. The only complication retinal detachment in the presence of symptoms and
was mild conjunctival avascularity in areas of signs of orbital cysticercosis, with a history of
pterygium excision in 30% of patients. In conclusion; exposure to an endemic area, should be considered
Long term evaluation revealed that the use of MMC to have orbital myocysticerci causing scleral
in pterygium surgery is safe, but for a strict selection indentation.
of patients, controlled use of MMC and long term
follow up are required.months and 18 months of Monthly Meetings Calendar
follow up, respectively. Mean (SD) visual acuity was For The Year 2004-2005
0.36 (0.15) and 0.35 (0.16) at the 12 and 18-month
follow- up period respectively. 12 eyes received two, 1st August, 2004 (Sunday)
seven eyes received three, and two eyes received four
IVTA injections. The mean (SD) interval between the Army Hospital (R&R)
first and second IVTA injection was 5.7 (2.67) months
and between the second and third was 5.7 (3.25) 29th Auguest, 2004 (Sunday)
months. Hard exudates were present in the macula
at baseline in all eyes. Progressive reduction in the Sir Ganga Ram Hospital
number and size of the hard exudates was noted after
IVTA in all cases. Intraocular pressure was raised 6th November, 2004 (Saturday)
above 21 mm Hg in 12 (40%) of 30 eyes. Two eyes Rescheduled : Hindu Rao Hospital
developed posterior subcapsular cataract and two
developed vitreous haemorrhage. In Conclusions: 30th October, 2004 (Saturday)
IVTA is a promising treatment for patients withDMO R.P. Centre for Ophthalmic Sciences
refractory to laser treatment. IVTA is effective in
improving vision, reducing macular thickness, and 21st November, 2004 (Sunday)
inducing reabsorption of hard exudates. Further DOS Midterm Conference
investigation is warranted to assessthe safety of IVTA
for the treatment of DMO. 27th November, 2004 (Sunday)
Dr. Shroff’s Charity Eye Hospital
Orbital cysticercosis-associated scleral in-
dentation presenting with pseudo-reti- 18th December, 2004 (Saturday)
nal detachment Venu Eye Hospital & Research Centre

29th January, 2005 (Saturday)
Safdarjung Hospital

Agrawal S, Agrawal J, Agrawal TP. Am J 26th February, 2005 (Saturday)
Ophthalmol. 2004 Jun;137(6):1153-5. M.A.M.C. (GNEC)

Authors report interventional case series of 27th March, 2005 (Sunday)
clinical picture similar to retinal detachment caused Mohan Eye Institute
by orbital myocysticercosis-associated scleral
indentation. Of the four patients with pseudoretinal 2nd & 3rd April, 2005 (Saturday & Sunday)
detachment, three were found to have orbital Annual DOS Conference

December, 2004 214 DOS Times - Vol.10, No. 5

FORTHCOMING EVENTS

NATIONAL Annual DOS Conference
2nd & 3rd April, 2005
63rd All India Ophthalmological Society Conference Contact : Dr. Jeewan S. Titiyal, Secretary DOS
13th - 16th January, 2005 R.No. 476, 4th Floor,
Contact : Dr. B. K. Tripathy, Organising Secretary, Dr. R.P. Centre for Ophthalmic Sciences
Bimal Tripathy Lane, Mahatab Road, AIIMS, Ansari Nagar, New Delhi – 110029
Cuttack – 753001, Orissa Ph : 91-011-26589549, 265888852-65 Ext. 3146
Ph : 0671-2310111, 2332483 Fax : 0671-2330111 Fax : 91-011-26588919
E-mail : [email protected] Email : [email protected]
Website : www.dosonline.org
INTERNATIONAL

ESCRS 9th Winter Refractive Surgery Meeting World Cornea Congress
4th - 6th Feb.2005 ROME, ITALY 13th - 14th April, 2005
Temple House,Temple Road WASHINGTON, DC
Blackrock, Co Dublin, Ireland Contact: ASCRS
Tel: +353 1 209 1100 Tel: +1 703 591 2220
Fax: +353 1 209 1112 Fax: +1 703 591 0614
Email: [email protected] Email: [email protected]
Web: www.escrs.org Web: www.ascrs.org

20th Asia Pacific Academy of Ophthalmology Congress ASCRS/ASOA Meeting Congress
27-31st March, 2005 16-20th April, 2005
Kuala Lumpur, Malaysia Washington, DC
Tel : +603-7956-3113 Fax : +603-7960-8297 Contact : ASCRS
Email : [email protected] Tel : +1-703-591-2220 Fax : +1-703-591-0614
Web : www.apao2005.com.my Web : www.ascrs.org

5th International Glaucoma Symposium XXIII Congress of the ESCRS
20th March, 2005 – 2nd April, 2005 10th - 14th Sept.2005 LISBON, PORTUGAL
Cape Town, South Africa Contact: ESCRS
Contact : Kenes International Temple House,Temple Road
Tel : +41-22-908-04-88 Fax : +41-22-7322850 Blackrock, Co Dublin, Ireland
Email : [email protected] Tel: +353 1 209 1100
Website : www.kenes.com/glaucoma Fax: +353 1 209 1112
Email:[email protected]
Web: www.escrs.orgSESept.2005PTEMBER

December, 2004 215 DOS Times - Vol.10, No. 5

TEAR SHEET

Evaluation of Visually Inattentive Baby

December, 2004 Harish Pathak, MD, Vijay B. Wagh, MD,FRCS M.S. Bajaj, MD
Dr. R. P. Centre for Ophthalmic Sciences
AIIMS, New Delhi - 110 029

216 DOS Times - Vol.10, No. 5

Delhi Ophthalmological Society Fellowship for
Partial Financial Assistance to Attend Conferences

Conferences 2) Type of Presentation

International: two fellowships per year a) Instructor/ Co-instructor of Course 10
Maximum of Rs. 25,000/-will be sanctioned
b) Free Paper (Oral) 08
National: three fellowships per year (only for AIOS)
Maximum of Rs. 5,000 will be sanctioned c) Poster 05

Eligibility 3) Institutional Affiliation
DOS Life Members (Delhi Members only)
Accepted paper for presentation / poster / instruc- a) Academic Institution 15
tion course
b) Private Practitioner 20
Time since last DOS Fellowship:
Preference will be given to member who has not 4) DCRS Rating in the immediate previous year

attended conference in last three years. However if no a) > 100 10
applicant is found suitable the fellowship money will be
passed on to next year. Members who has availed DOS b) 50-100 05
fellowship once will not be eligible for next fellowship for
a minimum period of three years. c) < 50 not eligible

Authorship Documents

The fellowship will be given only to presenting Proof for age. Date of Birth Certificate
author. Presenting author has to obtain certificate from all Letter of acceptance of paper for presentation / poster
other co-authors that they are not attending the said / instruction course
conference or not applying for grant for the same Details of announcement of the conference
conference. (Preference will be given to author where other Details of conference(s) attended in previous three
authors are not attending the same conference). If there is years.
repeatability of same author group in that case preference Copy of letter from other national or international
will be given to new author or new group of authors. agency committing to bear partial cost of conference
Preference will also be given to presenter who is attending if any.
the conference for the first time. At least one original document should be provided,
that is ticket, boarding pass or registration certificate
Quality of paper: along with attendance certificate of the conference.
The applicant has to submit abstract along with full Fellowship Money will be reimbursed only after
submission of all the required documents.
text to the DOS Fellowship Committee. The committee will Dr. Gurbax Singh (President DOS), Dr. Noshir M. Shroff
review the paper for its scientific and academic content. (Vice President DOS), Dr. Kamlesh (Editor) Dr. Lalit Verma
The paper should be certified by head of the department / (Library Officer), Dr. Sudipto Pakrasi (Member) Dr. J.C. Das
institution. In case of individual practitioner he or she and Dr. Jeewan S. Titiyal (Secretary DOS) will be the members
should mention the place of study. of DOS Fellowship for Partial Financial Assistance to
Attend Conferences Committee.
Credit to DOS: Application should be addressed to President, DOS.
The presenter will acknowledge DOS partial finan- Application should reach secretary’s office before 31st July
and 31st January for international conference and before
cial assistance in the abstract book / proceedings. 30th September for national conference. The committee
The author will present his or her paper in the imme- will meet thrice in a year in the month of August, October
and February with in 2 weeks of last date of receipt of
diate next DOS conference and it will be published in applications. The committee will reply within four weeks
DJO. of last date of submission in yes/no to the applicant. No
fellowship will be given retrospectively, that means prior
Points awarded: Points sanction of executive will be necessary.
10 Dr. Jeewan S. Titiyal
1) Age of the Applicant 07 Delhi Ophthalmological Society, R.No. 476, 4th Floor,
a) < 35 years 05 Dr. R.P. Centre for Ophthalmic Sciences, AIIMS, Ansari
b) 36 to 45 years Nagar, New Delhi – 110029
c) 45 years plus

December, 2004 217 DOS Times - Vol.10, No. 5

DOS Credit Rating System (DCRS)

DOS has always been in the forefront of efforts to In a bid to strengthen our efforts in this direction
DOS had DOS Credit Rating System (DCRS), the details
ensure that its members remain abreast with the latest of which are given below. Our Primary objective is to
developments in Ophthalmology. Among the important
objectives formulated by the founders of our promote value-based knowledge and skills in
constitution was the cultivation and promotion of the Ophthalmology for our members and give recognition
Science of Ophthalmology in Delhi. and credit for efforts made by individual members to
achieve standards of academic excellence in Ophthalmic
The rapid strides in skills and knowledge have Practice.

created a need for an extremely intensive Continuing
Medical Education programme.

DOS CREDIT RATING SYSTEM (DCRS) Max.

DCRS

1) Attending Monthly Clinical Meeting* † (For full attendence) 10 90

2) Making Case Presentation at Monthly Meeting** 15 —

3) Delivering a Clinical Talk at Monthly Meeting** 15 —

4) Free Paper Presentation at Annual Conference (To Presenter)** 15 30

5) Speaker/Instructor** in : Monthly Symposium 15 30

: Mid Term Symposium 15 30

: Annual Conference 15 30

6) Registered Delegate at Mid Term DOS Conference 20 —

7) Registered Delegate at Annual DOS Conference 30 —

8) Full Article publication in Delhi Journal of Ophthalmology/DOS Times 30 60

9) Letter to editor in DOS Times 10 20

10) Letter to editor in DJO 15 30

——————————————————————————————————————————————

If any of the presentations is given an Award – Addi- Please note that the Institutions’ grading increases if
tional 20 bonus Credits. the attendance at its meeting is higher (i.e. more than
the average attendence of the eight monthly meetings).
Member who have earned 100 Credits, are entitled to: ——————————————————————
* Based on Signature in DCAC
a) Certificate of Academic Excellence in Ophthalmic ** Subject to Submission of Full Text to Secretary, DOS
Practice. † Credits will be reduced in case attendence is only for
part of the meeting.
b) Eligible for DOS Travel fellowship for attending
conference. DCRS !! Attention !!

If any member earns 200 Credits, he/she shall, in * Members are requted to sign on monthly meeting at-
addition to above, be awarded Certificate of Distin- tendance register and put their membership number.
guished Resource-Teacher of the Society.
* The DCRS paper will be issued only after the valid
Institutional assessment for best performance will be signature of the member in the attendance register.
based on the total score of members who attend divided
by number of members who attended. Institutional as- * Please submit your DCRS papers to the designated
sessment regarding decision to retain the institute for DOS Staff only.
the next year will be based on total score by all delegates
who attend the meeting divided by average attendence * The collected DCRS papers will be countersigned by
of all 8 meetings. President and Secretary and sealed immediately ofter
the meeting is over.

December, 2004 218 DOS Times - Vol.10, No. 5

DOS Credit Rating System Report Card

DCRS July 2004 – Army Hospital (R&R)

Total No. of Delegates ................................................................................................................................................................. 83
Delegates from Out side (N) ........................................................................................................................................................ 75
Delegates from Army Hospital (n) ................................................................................................................................................ 8
Overall assessment by outside delegates (M) ..................................................................................................................... 610.5
Assessment of case presentation-I (Dr. Lt. Col. R. Maggon) by outside delegates ............................................................... 549
Assessment of case presentation-II (Dr. Lt. Col. (Mrs.) Madhu Bhaduria) by outside delegates ...................................... 541.5
Assessment of clinical talk (Dr. Col. Ajay Banajee) by outside delegates .......................................................................... 572.5
Rejected Form Army Hospital (n) .................................................................................................................................................. 2
Rejected Form Out side (N) ........................................................................................................................................................... 2

DCRS August, 2004 – Sir Ganga Ram Hospital

Total no. of Delegates (Valid DCRS forms) .................................................................................................................................. 86
Delegates from Out side (N) ........................................................................................................................................................ 76
Delegates from Sir Ganga Ram Hospital (n) ............................................................................................................................... 10
Overall assessment by outside delegates (M) ........................................................................................................................ 552
Assessment of case presentation-I (Deepti Manocha) by outside delegates ...................................................................... 475
Assessment of case presentation-II (Dr. Piyush Kapoor) by outside delegates .................................................................... 498
Assessment of clinical talk (Prof. H.K. Tewari) by outside delegates ...................................................................................... 571
Total no. of invalid DCRS forms .................................................................................................................................................. NIL

DCRS September, 2004 – Hindu Rao Hospital

Total No. of Delegates ................................................................................................................................................................. 45
Delegates from Out side (N) ........................................................................................................................................................ 32
Delegates from Hindu Rao Hospital (n) ...................................................................................................................................... 13
Overall assessment by outside delegates (M) ..................................................................................................................... 225.5
Assessment of case presentation-I (Dr. Vikas Anand / Dr. Ruchi Goel) by outside delegates .......................................... 214.5
Assessment of case presentation-II (Dr. Bithi Chowdhury) by outside delegates ................................................................ 216
Assessment of clinical talk (Dr. Ruchi Goel) by outside delegates ......................................................................................... 229
Rejected Form Hindu Rao Hospital (n) ...................................................................................................................................... NIL
Rejected Form Out side (N) ............................................................................................................................................................ 1

DCRS October, 2004 – Dr. R.P. Centre for Ophthalmic Sciences

Total No. of Delegates ................................................................................................................................................................. 57
Delegates from Out side (N) ........................................................................................................................................................ 38
Delegates from Dr. R.P. Centre (n) ................................................................................................................................................ 19
Overall assessment by outside delegates (M) ..................................................................................................................... 272.5
Assessment of case presentation-I (Dr. Balasubramanya R.) by outside delegates ............................................................ 261
Assessment of case presentation-II (Dr. Arun Singhvi) by outside delegates ....................................................................... 264
Assessment of clinical talk (Dr. Rajesh Sinha) by outside delegates ..................................................................................... 300
Rejected Form Dr. R.P. Centre (n) ................................................................................................................................................... 2
Rejected Form Out side (N) ........................................................................................................................................................ NIL

December, 2004 219 DOS Times - Vol.10, No. 5

DCRS November, 2004 – Shroff's Charity Eye Hospital

Total No. of Delegates ................................................................................................................................................................. 34
Delegates from Out side (N) ........................................................................................................................................................ 28
Delegates from Shroff's Charity Eye Hospital (n) .......................................................................................................................... 6
Overall assessment by outside delegates (M) ..................................................................................................................... 196.5
Assessment of case presentation-I (Dr. Umang Mathur) by outside delegates ................................................................ 180.5
Assessment of case presentation-II (Dr. Suneeta Dubey) by outside delegates ................................................................ 191.5
Assessment of clinical talk (Dr. Manisha Aggarwal) by outside delegates........................................................................... 207
Rejected Form Shroff's Charity Eye Hospital (n) ............................................................................................................................. 1
Rejected Form Out side (N) ............................................................................................................................................................ 1

!! Congratulations !!

Dr. V. Rajshekhar for completing observership in Vitreoretinal from Moorfields Eye Hospital, London.
Dr. Pankaj Lamba for being awarded Fellowship of Physicians and Surgeons of Glasgow (United
Kingdom) in October 2004.

Attention DOS Members

The Hi-tech DOS Library is functioning on Ground Floor, Dr. R.P. Centre, Delhi
Ophthalmic Sciences, AIIMS, New Delhi-110029 from 12.00 Noon to 9.00 P.M. on week
days and 10.00 A.M. - 1.00 P.M. on Saturday, Sunday. The Library will remain closed on
Gazetted Holidays. Members are Requested to utilise the Facilities Available i.e. Computer,
Video Journals Viewing, Latest Books and Journals. We are planning to subscribe two
journals member can give suggestion in this regard.

Dr. Lalit Verma, Library Officer, D.O.S.

Where is my copy of DOS Times ?

Dear DOS members, anyone who could not receive DOS Times from the month
of October, 2004 onwards. Please Contact:
President DOS : Dr. GURBAX SINGH Email : [email protected]
or
Secretary DOS : Dr. JEEWAN S. TITIYAL Email : [email protected]

December, 2004 220 DOS Times - Vol.10, No. 5

DOS QUIZ

DOS QUIZ NO. 16

1. Preferred type of foldable lens to be used in eyes with zonular dialysis
2. Chromatic interval between blue and red light is______________diopters
3. Ideal Illumination for snellen chart is _____________ lumens / square foot
4. Normal rate of loss of retinal ganglion cells__________ axons annually
5. Letter box visual field is seen in patients of ________ with patent______________artery.
6. The effective power of a cyclinder of power x - 30O away from its axis is __________________.
7. Antimetropia means________________ .
8. Maximum acurracy of Schiotz tonometer is when its scale reading is between________to_______.
9. Material used in vicryl suture is ________________
10. Two most common ophthlamic manifestations of congenital rubella are ______ and _________.

Rules:
• Please send your entries to the DOS office latest by 10th January, 2005.
• Prize Rs. 500/- Courtesy: Syntho Pharmaceuticals

ANSWERS OF DOS QUIZ NO. 14

1. Most Common ocular complication of AIDS
2. Most Common cause of chronic canaliculitis
3. Most important indication for strabismus surgery in congenital nystagmus
4. Classic triad of exophthalmos, bone lesions and diabetes insipidus is characteristic of
5. Overall what percentage of patients do not show a therapeutic effect from initial topical timolol treatment
6. Acquired sterioillusion in optic neuropathy is called
7. Most common site of metastasis of an ocular melanoma
8. Prism used in slit lamp is called
9. Friedenwall's chart & wallace's chart are used for ______________
10. Progresesion of gyrate atrophy may be slowed by a diet low _______ and high in Vit B6

Answers :
1. Microvasculopathy, 2. Actinomyces, 3. To correct head turn, 4. Histiocystosis X,
5. 10% 6. Pulfrich phenonenon, 7. Liver, 8. Porro Prism,
9. Ocular rigidity 10. Protein Sarginine

December, 2004 221 DOS Times - Vol.10, No. 5