dos_July_2014

Diagnostics

high depth resolution, which yields near-histological Figure 7: RNFL thickness average analysis
differentiation of the structures studied. This is based on
Michelson interferometer principle. OCT has optic nerve bottom one into four equal 90° sectors. Each sector
head analysis, RNFL analysis and macular parameter is represented with a number and color code. The
analysis. number represents the thickness expressed in microns,
1. Printout – ONH useful parameters (Figure 6) The useful and the color code indicates the possibility of that
value being found in the normal population:
parameters for an OCT printout of the ONH are: • Green and white: values found in up to 95% of the
• The raw and composite ONH scans. The composite
normal population.
scan is obtained from 6 to 24 scans. • Yellow: values found in less than 5% of the normal
• The individual and global stereometric parameters.
2. Printout – RNFL useful parameters. The useful population.
• Red: values found in less than 1% of the normal
parameters for an OCT printout of the RNFL are:
• Total, quadrant and clock-hour sectors of RNFL population.
6. Parameters table: The parameters table presents data
thickness. Clock-hour sectors consist of 12 equal
30-degree sectors. from both eyes plus inter-eye differences. Color
• An in-built normative database allows the indicates the probability of finding similar values in a
comparison between acquired measurements and normal population. The color coding and its statistical
data and normal, age-matched data. Comparison is significance are same as discussed above in RNFL
made if one of the sector type is selected. profile
• The differences between the two eyes (inter-eye Diagnostic Accuracy
differences), as both eyes are measured. Several studies have evaluated the diagnostic ability of
As RNFL analysis is widely reported and used, we will limit OCT parameters for glaucoma. In most of the published
our discussion to RNFL analysis. literature, RNFL thickness in the inferior region often had
Printout – RNFL the best ability to discriminate healthy eyes from those with
1. Patient and exam data: This includes name, date of glaucoma, with sensitivities ranging between 67% and
birth, gender and ID number. It also includes scan 84% for specificities of more than 90%. In our study, we
protocol used, date of the scan and analysis protocol have reported 6-clock, RNFL thickness parameter with very
selected. high positive likelihood ratio, which can virtually rule in
2. Fundus photography: It is obtained immediately after the disease if positive.
scanning, and is used to evaluate the correct position Pros
of the circular scan around the ONH. • Good reproducibility.
3. Signal strength: The signal strength is shown in the box • Correlates well with VF defects.
on the right (scale 1 to 10). The signal strength of 7 or
more is desirable.
4. RNFL thickness analysis (both eye): RNFL profile is a
graphic representation of the RNFL thickness around
the ONH. On the X-axis, the sector of the RNFL
is represented according to the temporal-superior-
nasal-inferior-temporal sequence: the circular scan
is linearly represented, starting from the temporal
region, continuing towards the superior, nasal, inferior
regions, and terminating in the temporal region. On the
Y-axis, thickness is expressed in microns (Figure7). The
patient’s RNFL graph is compared with age matched
normative database.
5. RNFL thickness measurements made around the ONH
for each eye are presented as two circles: The top
one is divided into 12 o’clock-hour sectors and the

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

Diagnostics

• SD-OCT don’t require dilation and 4. Bowd, C., et al., Structure-function relationships using confocal
• Shows exquisite details of different tissue layers, in scanning laser ophthalmoscopy, optical coherence tomography,
and scanning laser polarimetry. Invest Ophthalmol Vis Sci, 2006.
addition to the RNFL. 47: 2889-95.
• Pathology in other layers of the retina can be visualized
5. Wollstein G, Garway-Heath DF, Hitchings RA. Identification of
i.e peripapillary atrophy, optic nerve head drusen and early glaucoma cases with the scanning laser ophthalmoscope.
optic nerve pit. Ophthalmology 1998;105:1557-63.
Cons
• RNFL thickness values are affected by age, disc size 6. Lester M, Mikelberg FS, Drance SM. The effect of optic disc size
and tilt and axial length of the eye. on diagnostic precision with the Heidelberg Retinal Tomograph.
• TD-OCT may require dilation Ophthalmology 1997;104:545-48.
• Lacks an ethnicity-specific normative database.
• Progression analysis is difficult because the scan may 7. Swindale NV, Stjepanovic G, Chin A, Mikelberg FS: Automated
not be accurately centered on the ONH. analysis of normal and glaucomatous optic nerve head topography
• Although SD-OCT can perform progression analysis images. Invest Ophthalmol Vis Sci. 2000;41:1730-42.
and registration to the same location of scanning. TD-
OCT don’t have software to register follow-up scans to 8. Bowd C, Chan K, Zangwill LM, Goldbaum MH, et al. Comparing
the baseline. neural networks and linear discriminant functions for glaucoma
References detection using confocal scanning laser ophthalmoscopy of the optic
disc. Invest Ophthalmol Vis. Sci. 2002;43:3444-54.
1. Weinreb, R.N., A.W. Dreher, and J.F. Bille, Quantitative assessment
of the optic nerve head with the laser tomographic scanner. Int 9. Reus NJ, Lemij HG. Ophthalmology 2004;111:1860-65.
Ophthalmol, 1989. 13: 25-9. 10. Bowd C, Zangwill LM, Berry CC, et al. Detecting early glaucoma by

2. Pooja Sharma, BS et al. Diagnostic Tools for Glaucoma Detection assessment of retinal nerve fiber layer thickness and visual function.
and Management. Surv Ophthalmol. Nov 2008; 53(SUPPL1): S17– Invest Ophthalmol Vis Sci. 2001;42:1993-2003.
S32. 11. Da Pozzo S, Fuser M, Vattovani O, et al. GDx-VCC performance
in discriminating normal from glaucomatous eyes with early visual
3. Rajul Parikh et al. Optic Nerve Head and Retinal Nerve Fiber Layer field loss. Graefes Arch Clin Exp Ophthalmol. 2006;244:689-95.
Imaging in Glaucoma Diagnosis. Journal of Current Glaucoma 12. Brusini P, Salvetat ML, Parisi L, et al. Discrimination between normal
Practice, May-August 2009; 3: 8-19 and early glaucomatous eyes with scanning laser polarimeter with
fixed and variable corneal compensator settings. Eur J Ophthalmol
2005;15:468-76.
13. Tjon-Fo-Sang MJ, Lemij HG. The sensitivity and specificity of nerve
fiber layer measurements in glaucoma as determined with scanning
laser polarimetry. Am J Ophthalmol 1997;123:62-69.
14. Parikh RS, Parikh SR, Chandra Sekhar G, Prabakaran, et al.
Diagnostic capability of scanning laser polarimetry (GDx VCC) in
early glaucoma. Ophthalmology 2007 Nov 29; [Epub ahead of
print].

Book Review

The book titled “Principles And Practice of Vitreoretinal
Surgery“ by Dr. Narendran and Dr. Abhishek Kothari is a
comprehensive book updating the reader on the current practices
in vitreoretinal surgery.

The book is very systematically compiled with sections contributed
by distinguished vitreoretinal surgeons who are masters in their
own fields. The practical pearls in each chapter are very valuable.
The transition from basics to advanced techniques is gradual
and easy to comprehend. The sections on emerging techniques
provide insight into future trends and give better perspective of
the present practices. All major topics are precisely covered in
one volume which makes this book handy.

I recommend this book for core learning by the trainees and a
quick reference for the practicing surgeons.

Dr. Shalini Singh
Consultant Vitreoretina
Dr. Shroff’s Charity Eye Hospital
Daryaganj, New Delhi.

www. dosonline.org l 63

Goniosynechiolysis: Remedy MiscMeilslcaelnlaenoeouuss
for Synechial Angle Closure
Deven Tuli
MS

Deven Tuli MS
Glaucoma Consultant, New Delhi

Nearly half of primary glaucoma in adults in India is If angle closure persists after iridotomy, argon laser
angle closure and its sub classes. Unfortunately it was peripheral iridoplasty is the next step, if a double-hump
long under diagnosed and mismanaged as open angle sign characteristic of plateau iris is present. If the angle is
glaucoma leading to progressive optic nerve damage and not opened early enough, the chronic apposition will lead
consequent blindness. to increased pigmentation of the trabecular meshwork
Angle closure patients may have narrow angles, intermittent (TM) and eventually to the development of GS (finer) and
angle closure, appositional closure, or synechial closure PAS (wider, bulky)—permanent adhesions between the
with goniosynechae (GS) and peripheral anterior synechiae iris and the meshwork. Early opening of the angle can
(PAS), termed chronic angle closure. If glaucomatous optic restore aqueous outflow. Performing laser Iridotomy may
nerve damage is present, then angle-closure glaucoma not be the complete treatment if GS and PAS exist already
becomes the appropriate term. at presentation. If PAS are extensive and uncontrolled
Primary angle closure comprises angle closure due to relative glaucoma is present, surgical intervention becomes
pupillary block and plateau iris. It responds to pilocarpine necessary.
and laser iridotomy (LI) provides the definitive treatment Surgical Options
in these eyes and LI should be used in the treatment of Lens removal has been proposed as treatment for angle
all angle-closure mechanisms, on the presumption that any closure. Though it may work in cases of appositional
case of angle closure has some element of pupillary block. closure, unfortunately, cataract surgery alone does not
eliminate glaucoma in presence of significant GS and PAS.
(a) (b) Aung et al (2000) have shown that up to 32 percent of
patients with uncontrolled angle closure who underwent
Figure 1: Goniophotographs and UBM images (a): Pre GSL: phacoemulsification alone still had persistent synechiae
showing pre GSL synechial angle closure (b): Post GSL: Unzipped and uncontrolled pressure postoperatively2.
Reviewed here briefly is a contemporary treatment for
angle post GSL (Adapted from Ritch, 1999) synechial angle closure- Goniosynechialysis.
Goniosynechiolysis (GSL)
This was first described by Campbell and co-workers in
1984. It is designed to strip GS and PAS from the angle wall
and restore trabecular function. The procedure consists
of using a cyclodialysis spatula or an iris spatula, (less
recommended- a bent 25-gauge needle) to manually break
the GS and PAS.

www. dosonline.org l 65

Miscellaneous

Figure 2: Combined PhacoGSL results (Ritch 1999). closure and likely to have a shallower anterior chamber
Remarkable is much reduced need for filtering surgery and a steeper lens vault. Removing the lens creates more
space in AC and discourages the iris creeping back upto
When performing the procedure, the surgeon creates a the TM. The highest success rate, in another series, was
paracentesis. Once the anterior chamber has been filled expectedly with the patients in whom lens removal was
with viscoelastic and clear, direct visualization of the combined with GSL and pilocarpine was given post op for
angle (using the direct gonioscope and manoeuvring the short course4 (Harasymowycz et al, 2005).
microscope) is achieved, the synechiae are stripped one Complications of GSL
clock hour at a time. Following surgery, the patient should When compared to Trabeculectomy, IOP spike, iris trauma
undergo a course of steroids and pilocarpine used to help (tear or dialysis) and hyphema may occur more commonly
prevent reclosure of the angle. with GSL. On the flip side, bleb related issues, possible
In Campbell’s study (1984), GSL was successful in 80 hypotony and flat AC are negligible complications with
percent of eyes, with minimal complications, as long as the GSL procedures.
synechiae had been present in the angle for less than one When to avoid GSL? Though generally, GSL is a safe
year. However, the authors also noted that the synechiae procedure, however it should be avoided or done with
could recur in eyes that continued to have crowding of the caution in patients with neovascular glaucoma, eyes with
anterior chamber1. significantly advanced glaucoma damage and eyes with
Ritch et al in 1999 described the results of a large long standing (> 1 year) PAS.
series of GSL procedures. They performed combined
phacoemulsification and GSL in 81 patients who had had Observations regarding GSL from literature
primary angle closure for less than six months and had • It is preferred to offer GSL to a patient undergoing
uncontrolled IOP following laser surgeries. In this series
patients also had synechiae in more than 180 degrees of cataract surgery even if IOP was controlled on 2-3
the angle. medications post laser in a chronic ACG situation.
Postoperative IOP was reduced to the low or mid-teens, • GSL may have better results if patient only has upto
regardless of the preoperative IOP. (Figure 1 and 2). Eighty- 180 degrees of PAS compared to another where PAS
nine percent of the subjects had a significant reduction are nearly 360 degrees.
of synechiae, and their IOP was controlled without • If GSL can relieve elevated IOP in angle closure, it
any medications; only 3 percent required subsequent is a far safer way to reduce IOP than more extensive
trabeculectomy. The success rate did not change after surgery (trabeculectomy); it utilizes the natural outflow
the third postoperative month, and IOPs were stable with pathway, and it doesn’t have the kind of long-term risks
longer follow up. seen with filtration procedures. It’s certainly an option
This series also demonstrated that with GSL, it is important to consider when managing a patient with angle-
to remove the lens. Again, most of these eyes have angle closure issues.
• In future GSL is likely to have wider use across
the world. Those well versed with gonioscopy can
conquer the learning curve much easier. Also ancillary
use of anterior segment OCT will allow better view of
the angle and make the procedure safer. Use of high
viscous devices can help disrupt the synechiae better.
(viscoGSL)
References

1. Campbell DG, Vela A. Modern goniosynechialysis for the
treatment of synechial angle-closure glaucoma. Ophthalmology.
1984;91(9):1052–60.

2. Aung T, Tow SL, et al. Trabeculectomy for acute primary angle
closure. Ophthalmology 2000:107:1298-1302.

3. Teekhasaenee C, Ritch R. Combined Phaco GSL for uncontrolled
chronic angle-closure glaucoma after acute angle-closure glaucoma.
Ophthalmology 1999;106:669-75.

4. Harasymowycz PJ. et al. Phacoemulsification and goniosynechialysis
in the management of unresponsive primary angle closure. J
Glaucoma 2005; 14:186-9.

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

Evolution of Glaucoma EvoElvuoltuitoionn
Surgery
Sonal Dangda
MS,DNB

Sonal Dangda MS,DNB, Kirti Jaisingh MS, Yashpal Goel MS, Amrit MBBS, Shraddha Saraf MBBS
Guru Nanak Eye Centre, New Delhi

Surgical treatment for glaucoma has seen a paradigm shift Here we review the evolution of glaucoma surgeries which
since the later half of the 19th century, when Albretch formed the basis of treatment in the early 20th century to
von Graefe first proposed surgical iridectomy way back in the recent advancements in near future.
1856. Researches since then have evolved from creating a In 1856, von Graefe introduced peripheral surgical
“filtration cicatrix” to surgical wound modulation and the iridectomy, which worked well in patients with acute angle
more sophisticated shunts and stents. closure and those with pupillary block due to seclusio
Treatment for glaucoma can be broadly categorised on two pupillae1. With time, these iridectomies became larger but
fundamental basics. spectrum of patients who could benefit remained the same.
1. Decreasing the inflow/production of aqueous humor It was slowly realised that smaller iridectomies could also
serve the purpose and the approach shifted from surgical
and to non-surgical with the advent of laser delivery systems.
2. Increasing the aqueous outflow – which can further be Even after being the mainstay for fifty years, the realisation
that iridectomy alone does not result in drastic intraocular
divided into pressure lowering, the approach shifted towards creating
a) creating an alternative outflow pathway or a fistula for aqueous drainage. De Wecker in 1867 laid
b) enhancing the pre-existent one the foundation for future glaucoma filtration surgeries by
Medical therapy in glaucoma is mostly directed towards describing anterior sclerotomy which he named as the
the inflow mechanism. Destruction of ciliary body either “filtration cicatrix”1. Dianoux advocated ocular massage
by surgical excision or use of techniques like irradiation, to keep this cicatrix permeable by preventing primary
cryofreeze, and of late laser photocoagulation also aims at intention healing2. This anterior sclerotomy was described
the same. as a full thickness scleral incision 1 mm posterior to the
Glaucoma filtering surgery aims to provide an outflow limbus, Subsequently many modifications were suggested,
of the aqueous through an alternative path from the a few popular ones being3,4 –
anterior chamber to the sub-conjunctival space or the a. Lagrange- excised a piece of tissue from the anterior lip
suprachoroidal space. There are two basic types of fistula
in glaucoma filtering surgery – of the wound (Figure 1).
1. Extending through the full thickness of limbal tissue. b. Herbert- made one or both the lips of incision jagged
2. Fistula guarded by a partial thickness scleral flap.
Surgical techniques for enhancement of the pre-existing and uneven by sawing movements of knife and cut out
filtration pathway aim at decreasing the resistance at the a wedge which would shrink sufficiently to provide
juxtacanalicular trabecular meshwork and inner wall of for filtration but not enough to cause an actual fistula
schlemm’s canal. formation.
c. Holth- used punch forceps to cut anterior lip of wound.
d. Iliff and Hass- introduced posterior lip sclerectomy in
1960s.

www. dosonline.org l 67

Evolution

Figure 1: Sclerectomy: Lagrange’s procedure

Figure 2 was applied to the bare sclera until anterior chamber was
entered however iridectomy was not done6.
The next major advancement came in 1909 in the form Scheie modified this procedure by using cautery to retract
of trephination introduced independently by Fergus and the wound edges. After doing peritomy, cautery is applied
Elliot3. The fistula was created using a Bowman’s trephine; to the sclera 1mm behind the limbus. A 5mm incision is
while Fergus removed a scleral disc of 1-2mm from then made in the cauterized sclera and cautery applied to
the apparent corneal margin with no iridectomy, Elliot edges until a gape of 1mm remains between them followed
removed a sclero-corneal disc anteriorly combined with an by aniridectomy7. Blebs produced hereby were flatter and
iridectomy. more diffuse than those with trephination or Preziosi’s
A special instrument called sclerectome was introduced procedure (Figure 3).
for trephination by Verhoeff which could cut 1mm disc Another procedure which gained momemtum was Holth’s
from corneal margin with a small button hole in the iris. operation/ Iridencleisis. In this, iris is grasped after making
However these procedures produced extremely thin blebs, a sclerotomy short distance from the limbus and incised in
hence Sugar advocated a more posterior limbo scleral a manner that one pillar can be incarcerated through the
approach5 (Figure 2). wound. The conjunctival flap is then used to cover the laid
Introduced in 1924 by Preziosi, Thermal Sclerostomy out iris and the wound is closed with a running suture8.
made use of electrocautery to create the fistula; cautery The fear of sympathetic ophthalmia played a role in the
abandonment of this once extremely popular operation for
primary open-angle glaucoma (Figure 4).
Around the same time, Heine described Cyclodialysis,
which involved the separation of ciliary body from the
scleral spur thus creating a direct communication into
the suprachoroidal space. This worked by increasing the
uveoscleral outflow and decreasing the aqueous production,
both mechanisms causing a lowering the IOP. The surgery
described was done by making a conjunctival incision 8mm
from the superior limbus followed by a full thickness scleral
incision 3-4mm from the limbus. A cyclodialysis spatula
was then inserted through it into the supraciliary space till

Figure 3: Thermal Sclerostomy - Scheie

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

Evolution

Figure 4: Clinical and gonio picture of an eye with iridencleisis scar and Dianoux advocated a prevention of primary
intention healing which was later popularized by use
the anterior chamber and moved sideways severing 1/3rd of pharmacological wound modulators in the form of
of ciliary body from the scleral spur9. antifibrotics like 5-flourouracil, mitomycin C, anti-VEGF
All these above surgeries were full thickness filtering etc.12 However, widespread cellular toxicity of these
procedures as the fistula were covered only with drugs has worked like a double edged sword and the use
conjunctiva. Although these procedures achieved a very of these drugs is not free from serious sight threatening
good control of IOP, but due to no check on the aqueous complications related to hypotony like shallow chambers,
outflow this IOP control was often achieved in exchange choroidal detachments and haemorrhage, bleb related
for excessive aqueous filtration leading to prolonged flat infections and snuff out phenomenon. Suture modulations
anterior chambers, corneal decompensation, synechiae, in the form of adjustable and releasable sutures and laser
cataract formation and prolonged hypotony. The filtering suture lysis help the glaucoma surgeon in somewhat
blebs were thin and susceptible to rupture, thus creating negating the above side-effects in the early postoperative
increased risk of endophthalmitis. Hence arose the need to period caused due to overfiltration13.
look for modifications which could circumvent the above There still are situations were chances of success are
problems. minimal and other alternatives need to be looked for. The
Partial Thickness/ Guarded Fistulas Glaucoma Drainage Devices (GDD) provides some respite
With this aim of controlling the filtration rate, Sugar in 1961 in such high failure cases. Historically these shunts date back
made the fistula underneath the scleral flap and sutured to late 19th century; deWeckers used ‘gold wire implants’
the flap tightly to sclera to prevent excessive external in patients with failed sclerotomies. Other notable ones
filtration and thereby preventing hypotony10. Modern day include ‘Horse hair shunt’ by Rollet in 1906 and permanent
trabeculectomy, which is till date considered the gold silk thread implants independently in 1912 by Zorab and
standard in glaucoma filtration surgery, was heralded Mayou2. Much before the modern tube shunt by Molteno
by Cairns in 196811. He conceptualised that the outflow in 1969, Qadeer devised a plastic plate for subconjunctival
could be increased by bypassing the trabecular meshwork insertion with drainage channels engraved in it and its head
and draining directly into the aqueous veins through the was placed in the anterior chamber which through a hole
opened ends of the Schlemm’s canal. drained the aqueous into those channels14. The modern day
But achieving an ideal balance for an optimal filtration is implants consist of a silicon tube extending from anterior
far from reality. Post-operative scarring of filtration bleb chamber or vitreous cavity to a plate, disc or encircling
is a known entity since the time of ‘filtration cicatrix’ of element around which the filtering bleb forms. Whereas
deWecker. Glaucoma filtration surgery is a ‘non healed’ Baerveldt, Molteno and Schocket implants are open tube
devices, Ahmed and Krupin have a flow restricting valve
mechanism that inherently provides them the property to
function only at a specific range of IOP and preventing
early hypotony.
Other popular surgical procedures include Trabeculotomy
and goniotomy used primarily in congenital glaucoma.
Trabeculotomy was introduced in 1960 by Burian and
Smith and later modified by Harms and Dannheim15. Smith
used a nylon or prolene suture instead of a trabeculotome
to thread the Schlemm canal 360°, and pull it taut thus
rupturing the trabecular meshwork16. Otto Barkan in 1938
introduced Goniotomy as the technique for incising the
trabecular meshwork gonioscopically. It is one of the most
successful techniques in vogue for childhood glaucoma17.
Non-Penetrating Glaucoma Surgery (NPGS)
Although initially proposed by Krashnov in 1964, it
emerged as a novel surgical alternative in 1990s only. Here,
the filtration occurs across a semipermeable structure,
maintaining some resistance to outflow and decreasing the
rates of over filtration and hypotony. It enjoys a better safety
profile since the anterior chamber is not entered. Mainly
consisting of deep sclerectomy and viscocanalostomy,

www. dosonline.org l 69

Evolution

these act by increasing the aqueous outflow through the 7. Scheie HG. Retraction of scleral wound edges as a fistulising
micro perforations created in the trabeculo-descemet procedure for glaucoma. Trans Am Acad Ophthalmol Otolaryngol.
membrane by peeling of the inner wall of schlemm canal. 1958;62(6):803-11.
Also micro ruptures occur in the wall of Schlemm canal
on injecting viscoelastic. Numerous modifications have 8. Gess LA, Koeth E, Gralle I. Trabeculectomy with iridencleisis. Br J
been introduced since the advent of NPGS to improve the Ophthalmol.1985;69(12):881-5.
success rates18,19.
Other Recent Advances - Recently developed technologies 9. Heine L. Die Cyklodialyse, eineneue Glaucomoperation. Deutsche
that are substantially less invasive than trabeculectomy Med Wehnschr. 1905;31:825.
and do not depend on external filtering bleb formation
or adjunctive antifibrotic agents promise to herald a 10. Sugar HS. Experimental trabeculectomy in glaucoma.Am J
new era in glaucoma surgery. However, they are yet Ophthalmol. 1961;51:623-27.
to demonstrate their long-term efficacy. These include
Trabectome (Trabecular Microelectrocautery), Glaukos 11. Cairns JE. Surgical treatment of primary open angle glaucoma. Trans
I Stent (Trabecular micro-bypass), SOLX Gold shunt and OpthalmolSoc UK. 1972;92:745-56.
ExPress mini-glaucoma shunt20-23.
Being independent of the conjunctival status, these newer 12. Lama PJ, Fechtner RD. Antifibrotics and wound healing in glaucoma
procedures hold good chances of success in difficult surgery. SurvOpthalmol. 2003 may-june;48(3):314-46.
situations like aphakic, pseudophakic, post penetrating
keratoplasty glaucoma etc. Besides they do not cause 13. Kolker AE, Kass MA. Trabeculectomy with releasable sutures. Trans
sufficient scarring to preclude subsequent conventional Am Ophthalmol Soc. 1993;91:131-45.
surgery.
Thus glaucoma surgery has come a long way from 14. Qadeer SA. Acrylic gonio-subconjunctival plates in glaucoma
the formation of a mere filterationcicatrix to the use of surgery. Br J Ophthalmol 1954;38:353–6.
sophisticated technologies for achieving a good success
rate. The technological advancements have already given a 15. Harms H, Danheim R. Trabeculotomy results and problems. In:
new insight to the glaucoma scientists and the future is sure MacKensen G, ed. Microsurgery in Glaucoma. Basel, Switzerland: S
to witness many more such advances. Karger; 1970:121.
References
16. Smith R. A new technique for opening the canal of Schlemm.
1. Hirschberg J. The History of Ophthalmology, vol 11. Bonn, Preliminary report.Br J Ophthalmol. 1960;44:370-3.
Germany: JP Wayenborgh;1994.
17. Barkan O. Technique of goniotomy. Arch Ophthalmol. 1938;19:217-
2. Sugar HS. The Glaucomas, 2nd ed. New York, NY: Hoeber- 21.
Harber;1957.
18. Kozlova T, Zagorski ZF, Rakowska E. A simplified technique for non-
3. Elliot RH. Sclero-corneal trephining in the operative treatment of penetrating deep sclerectomy.Eur J Ophthalmol. 2002;12(3):188-92.
glaucoma. London: George Pulman and Sons;1913.
19. Carassa RG, Bettin P, Fiori M, et al. Viscocanalostomy: a pilot study.
4. Iliff CE, Haas JS. Posterior lip sclerectomy.Am J Ophthalmol. Eur J Ophthalmol. 1998;8(2):57-61.
1962;54:688-93.
20. Minckler DS, Baerveldt G, Alfaro MR, et al. Clinical results with the
5. Sugar HS. Limboscleral trephination.Am J Ophthalmol. 1961;52:29- Trabectome for treatment of open angle glaucoma. Ophthalmology.
36. 2005;112(6):962-7.

6. Preziosi CL. The electro-cautery in the treatment of glaucoma.Br J 21. Bahler CK, Smedley GT, Zhou J, et al. Trabecular bypass stents
Ophthalmol. 1924;8(9):414-17. decrease intraocular pressure in cultured human anterior segments.
Am J Ophthalmol. 2004;138(6):988-94.

22. Melamed S, Ben Simon GJ, Goldenfeld M, Simon G. Efficacy and
safety of gold micro shunt implantation to the supraciliary space
in patients with glaucoma: a pilot study. Arch Ophthalmol. 2009
Mar;127(3):264-9.

23. Wamsley S, Moster MR, Rai S, et al. Results of the use of the Ex-
PRESS miniature glaucoma implant in technically challenging,
advanced glaucoma cases: a clinical pilot study. Am J Ophthalmol.
2004;138(6):1049-51

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

Pathophysiology of Angle PG PCGoCronrneer
Closure Glaucoma
Kirti Jaisingh
MS

Kirti Jaisingh MS, Sonal Dangda MS
Guru Nanak Eye Centre, New Delhi

Angle closure glaucoma is a leading cause of blindness 2) Dynamic Factors:
worldwide. In South-East Asian countries, it is as • Dim illumination.
prevalent as primary open angle glaucoma (POAG) and is • Emotional stress.
more visually destructive than POAG. In Eskimos/ Inuits • Drugs.
the prevalence of PACG is felt to be higher than any • Choroidal expansion due to any etiology.
other ethnic group1. In angle closure glaucoma, increased Relevant Anatomy of the Angle
intraocular pressure is caused by impaired outflow facility Angle of the anterior chamber plays an important role in
secondary to appositional or synechial closure of the the process of aqueous drainage. From posterior to anterior,
anterior chamber drainage angle. Although angle closure the angle recess is formed by the following (Figure 1):
in all its forms is vision threatening, early diagnosis and 1) Ciliary body band (CBB): It is the portion of ciliary
appropriate management can stabilize disease and
minimize vision loss. body visible in the anterior chamber as a result of iris
Various risk factors have been implicated in the pathogenesis insertion into the ciliary body. Clinically, it appears to
of glaucoma such as1: be grey or dark brown in colour.
Demographic Factors 2) Scleral spur (SS): It is the posterior lip of scleral
1) Old age (peak in 55-70 years). sulcus, attached to ciliary body posteriorly and the
2) Ethnicity (more in South-East Asian countries, Inuits). corneoscleral meshwork anteriorly. Clinically, It
3) Gender (more in females). appears as a prominent white line between the ciliary
4) Family History (especially with a first degree relative). body band and functional trabecular meshwork.
Anatomic Factors 3) Trabecular meshwork (TM): It is a sieve like structure
1) Static Factors: through which aqueous humour leaves the eye.
• Shorter axial length. It bridges the scleral sulcus and converts it into a
• Shallow anterior chamber depth. tube which accommodates the Schlemm canal. The
• Thicker lens or increased anterior curvature of meshwork consist of 3 portions:
a) Uveal meshwork Innermost- part extending from
lens.
• Relatively anteriorly positioned lens. iris root to Schwalbe’s line. It is 2-3 layer thick and
• Smaller cornea. has 25-75 micron thick openings.
• Increased anterior curvature of iris. b) Corneoscleral meshwork- Middle portion
• Plateau iris configuration . extending from scleral spur to lateral wall of scleral
sulcus. Here, the openings become progressively
smaller as they approach Schlemm canal (5-50
micron to even 1-2 microns).

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Table 1: Van HerickGrading of the width of anterior chamber with its corresponding Shaffer grading of the angle

Van Herick ACD CT Shaffer Grade Degrees Interpretation
Grade

4 ACD = or > CT

4 wide open 40 degrees Closure improbable

3 ACD = 1/4 to 1/2 CT 3 open 30 degrees Closure
improbable

2 ACD = 1/4 CT

2 moderately 20 degrees Closure possible
narrow angle

1 ACD < 1/4 CT 1 extremely 10 degrees Closure
narrow angle probable

Slit ACD = Slit Slit <10 degrees Areas appear
closed

c) Juxtacanalicular (endothelial) meshwork- It is segment OCT have revolutionalized our knowledge of the
the part that mainly offers resistance to aqueous pathogenesis of ACG. Angle closure glaucoma (ACG) is an
outflow. It consists of 2-5 layers and its outer anatomical disorder comprising a final common pathway
endothelial wall merges with the inner endothelial of closure of drainage angle by appositional or synechial
wall of Schlemm canal. approximation of the iris against the trabecular meshwork,
resulting from various abnormal relationships of anterior
• Clinically, trabecular meshwork is seen as segment structures. These abnormal relationships result
a pigmented band anterior to scleral spur. from one or more abnormalities in relative or absolute sizes
Posterior part of TM which lies adjacent to the or positions of anterior segment structures, or posterior
Schlemm canal is the functional part. segment forces that alter anterior segment anatomy. The
forces causing iris apposition to trabecular meshwork may
4) Schwalbe’s line (SL): It is formed by the prominent end originate at following 4 levels2:
of Descemet’s membrane of the cornea. By using a thin 1. Posterior chamber (pupillary block)
slit beam at a slightly oblique angle, this line can be 2. Ciliary body (plateau iris)
identified by the corneal wedge created by light wedge 3. Lens (phacomorphic glaucoma)
created at the junction between the inner light beam 4. Posterior to lens (malignant glaucoma)
along the corneal endothelium and the outer light Following are the mechanisms involved and they often
beam along the corneoscleral junction. occur simultaneously:
Pupillary Block Mechanism
• Width of the angle can be determined by assessing Pupillary block is the most frequent and important
the peripheral anterior chamber depth by Van mechanism. Usually, there exists a pressure differential
Herrick’s method or gonioscopically3. Clinically, of 0.23 mm Hg between posterior and anterior chamber,
these structures can be visualized gonioscopically which drives the aqueous humour from posterior to
and the most common classification used to grade anterior chamber. This pressure differential may increase
angle width is given by Shaffer (Table 1). greatly when the dimensions of iris-lens channel are

Mechanisms In Angle Closure Glaucoma

The advances in visualizing the angle with the help of
gonioscopy, ultrasound biomicroscopy and anterior

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Figure 1: Gonioscopic view of an open angle

changed. The iris becomes more convex then and 1st an Figure 2: Pupillary block mechanism
iridocorneal contact develops followed by apposition of
iris to TM resulting in clinically significant pupillary block. pupillary dilatation and accomodation. A mid dilated pupil
The variables that interact to determine iris contour include of 3.5-6 mm is the critical degree of dilatation that brings
anatomic variations in eye size, lens size and position, the attack in such predisposed eyes (Figure 2).
iris stroma and musculature characteristics, ciliary body
anatomy and physiologic variations occurring during

Variable Force due to sphincter Force due to dilator Force due to stretching of iris
contraction (S) contraction (D) tissue (E)

It is a force acting towards the axis It acts from the point of iris-lens Contraction of sphincter results
of pupil, at right angle to antero- contact to the iris insertion (A in stretching of iris tissue. This
posterior axis (Figure 3) to B) (Figure 4) force resists contraction and acts
in similar direction to D (A to B)
(Figure 4)

Pupil blocking Considering p as the angle Considering q as the angle Same as force due to dilator
component between S and perpendicular at between D and perpendicular contraction
the point of iris lens contact, S at the point of iris lens contact,
cos p depicts the force pulling iris D cos q depicts the force pulling
onto lens (Figure 5) iris onto the lens (Figure 6)

Effect of Angle p decreases, so S cos p Angle q increases, so D cos q Same as D cos q
dilatation increases i.e. pupil blocking force decreases i.e. pupil blocking
increases (Figure 7) force decreases (Figure 8)

Effect of lens Since angle p doesn’t change, so Since angle q decreases Same as D cos q
position no effect of forward positioning of with forward positioning of
lens (Figure 9) lens, so D cos q or the pupil
blocking force increases with
forward positioning of lens and
accommodation (Figure 10)

Effect of tone It increases with excitation and It increases with inhibition and It is indirectly affected. Miosis
of autonomic decreases with inhibition, S cos p decreases with excitation, D decreases q and mydriasis
nervous changes accordingly cos q changes accordingly increases q so reverse is true for
system its pupil blocking force i.e. E cos q

Effect of drugs Para sympathomimetics increase Sympathomimetics increase D Indirectly affect by causing miosis
S and thus S cos p also whereas, and thus D cos q also whereas, or mydriasis
parasympatholytics decrease S sympatholytics decrease D and
and thus S cos p also decreases thus D cos q also decreases

On entering a darkened room, dilatation occurs due to sphincter relaxation and dilator muscle contraction, thereby increasing S cos p and decreasing
(D+E) cos q. When the pupil is mid dilated, S cos p is increased considerably and (D+E) cos q is not completely extinguished resulting in maximal
pupil blocking force. Further, their is more lax, bombe more readily occurs, and with it closure of a narrow angle.

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PG Corner Fig.4

Fig.3

Figure 3 & Figure 4 Figure 8
Figure 9
Fig.5 Fig.6

Figure 5 & Figure 6

Figure 7 Figure 10

Two mathematical models explaining the influence of a Tiedman Theory6
mid-dilated pupil are The Tiedeman analysis treats iris as a thin shell firmly
• Mapstone Theory attached at the iris root. The forces acting onit are those;
• Tiedman Theory 1. Due to radially oriented dilator fibers,
Mapstone Theory4,5 2. Due to centrally oriented sphincter, pupillae fibres,
The forces acting at the iris-lens channel and iris surface are 3. The force acting to hold it to the iris root,
givn in (Table 2 and Figures 3-10). 4. The hydrostatic pressures in the posterior and anterior
Ultrasound biomicroscopy supports this model.
chamber.

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Figure 11: Z is the axis passing through iris root thus determing the relative lens position

Figure 12 : 1. showing iris shape in normal conditions, 2. showing iris shape in mid dilated position closing the angle, 3.
showing iris shape in fully dilated condition. 1,2,3 on lens surface depict the position of pupil.

The iris in the model takes on a convex shape, which body but due to an iridociliary cyst pushing the iris
increases in forward bowing when the lens is more anterior from behind (Figure 15).
relative to the iris root (Figure 11). Lens Induced ACG
The model also predicts that the iris shape will come closest In this form, lens moves forward excessively, pushing the
to closing off the angle when the pupilis in the mid-dilated iris forward, into the anterior chamber. This can either be
position (Figure 12), as during acute attacks. Athicker iris due to zonule laxity as in lens subluxation or due to the
stroma would not affect iris shape, but would increase development of positive pressure in the vitreous space as in
the pressure differential between posterior and anterior malignant glaucoma. This subset worsens with miotics and
chambers. improves with mydriatics-cyclopegics since they tighten
Plateau Iris Syndrome (PIS) the ciliary body-zonular ring and move the lens posteriorly.
The anteriorly positioned ciliary processes prop up the Ciliochoroidal Expansion Syndromes
iris anteriorly resulting in peripheral iris being held These raise the IOP throughout the eye. As aqueous humor
forward in contact with TM. On indentation gonioscopy, a leaves via the conventional pathway, normal posterior-
characteristic double iris hump is seen (Figure 13). Removal anterior differential significantly increases depending on
of lens or peripheral iridotomy do not alter the iridociliary the level of iris-lens channel resistance. The related anterior
apposition (Figure 14). rotation of ciliary body and lax zonules contribute as well.
• Pseudoplateau Iris: the typical configuration of Such a secondary ACG occurs in:

peripheral iris is not due to anteriorly positioned ciliary

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Figure 15: Pseudoplateau iris with iridociliary cyst

Figure 13: Double hump seen on gonioscopy d) High vortex vein pressure (Sturge Weber, CRVO,
orbital tumors, carotid-cavernous fistula, scleral
Figure 14: Plateau iris not opening up after iridotomy buckling surgery)

a) Choroidal haemorrhage e) Pharmacologic reactions (topiramate, sulpha derived
b) Metastatic tumors medications)
c) Inflammation (uveal effusion, Vogt Koyanagi Harada,
Anterior ACG (Pull Mechanisms)
panretinal photocoagulation) These pathologies cause initial synechial closure in
contrast to most others described above which first cause
appositional closure and then synechial closure. Examples
include closure by a proliferating fibrovascular membrane
(neovascular membrane), proliferating endothelial
membrane (iridocorneal endothelial syndrome), by
contracting inflammatory keratic precipitates making
contact with iris from the TM (sarcoidosis and chronic
uveitis), etc.
References

1. Tarongoy P, Ho CL, Walton DS. Angle-closure glaucoma: The role
of the lens in the pathogenesis, prevention, and treatment. Surv.
Ophthalmol. 2009;54:211-25.

2. Robert R, Liebermann JM. Angle Closure Glaucoma. Asian J.
Ophthalmol. 1999;1:10-6.

3. Van Herick W, Shaffer RN, Schwartz A. Estimation of width of angle
of anterior chamber. Incidence and significance of narrow angle.
Am J Ophthalmol. 1969;68:626-9.

4. Mapstone R. Acute shallowing of the anterior chamber.Br J.
Ophthalmol. 1981;65:446-51.

5. Mapstone R. Mechanics of pupil block. Br. J. Ophthalmol.
1968;52:19-25.

6. Tiedeman JS. A physical analysis of the factors that determine the
contour of the iris. Am J Ophthalmol. 1991;111:338-43.

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MonthlyMoMntheleytMineegtinCgoCronrneerr

Phakic IOLs in Correcting Rajesh Hans
Refractive Errors MD

Rajesh Hans MD
Department of Ophthalmology, D.D.U. Hospital, New Delhi

Phakic IOLs, as surgical treatment of ametropia, has History
been available to Ophthalmologists, for more than The first ideas of implanting ‘plastic’ phakic IOLs were
half a century now. The advantage of their use lies in the formed and implemented by Strampelli (1953) and
ease of their implantation, at a significantly lower cost of Barraquer (1959. However these lenses needed explantation
instrumentation. Presently, PRL and ICL are the usually due to complications like UGH syndrome. The modern
favored Phakic IOLs (pIOLs), that are being used by most of generations pIOLs were started by Baikoff and Joly2-6, in
the surgeons for myopia and hyperopia. Toric pIOLs are also late 1980s. These were PMMA pIOLs, rigid and designed
being used for surgically treating astigmatism successfully. for anterior chamber. Their design was similar to Kelman
The pIOL is inserted in the anterior or posterior chamber Multiflex. Fyodorov and Zuev7, implanted ‘collar button’
depending on its design. The idea is to provide the refractive pIOLs. These were also discontinued due to complications
correction by placing a lens anterior to the crystalline lens like corneal decompensation, chronic iritis etc. Fechner
and sufficiently posterior to corneal endothelium. This and Worst introduced phakic iris – claw lens in 1988. Their
allows the preservation of accommodation and reduces design increased the distance from corneal endothelium.
the complications to a minimum level. Another major
advantage is the reversibility of this surgery.
Introduction
At present, three types of Phakic IOLs (pIOLs) are being
commonly used: 1) angle supported anterior chamber
lenses, 2) iris supported lenses and 3) posterior chamber
lenses;. Each type has its own advantages, disadvantages
and peculiarities. The general indication for pIOLs
include myopia >9.0D and hyperopia >4.0D. The
patients unsuitable for this surgery are those with high and
progressive astigmatism, significant intraocular diseases
and severe debilitating systemic illnesses. The posterior
chamber pIOL made by Staar (ICL) can be placed through a
smaller incision, but must unfold in the anterior chamber.
Potentially, it may unfold upside-down and cause trauma.
Other lenses may require an incision about 6mm. long. If
properly done, these contribute to minimal astigmatism
(about 0.5 D) and do not, interfere with postoperative
visual acuity1.

Figure 1: Angle-supported Baikoff ZB5M (left) and
the NuVita MA 20 (right)

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1990s saw Artisan (Ophtec) and verisyse (Abbot). These Figure 2: Post LASIK Topograph showing
lenses had high ‘vault’ of 0.87 mm. and were placed 1.5 to corneal ectasia.
2mm. behind the corneal endothelium. They had iris-claw
design, single piece and U-V filter PMMA. They were aimed on tissue healing so no regression is seen with time. The
at reducing the postoperative complications. Then foldable correctable range is from -20D to +20 D. If the glare and
iris-claw lens (Artiflex) was introduced. Gradually, various haloes are distressing, the surgery can be easily reversed by
angle supported designs, plano-concave shapes, flexibility explanting the pIOL. Accuracy and predictability allows for
of haptics and treatment of the lens material eg. Fl-plasma long term stability of the refractive status. There is no post
for Nuvita and Heparin for Phakic-6 were introduced. surgical corneal ectasia even after treating high degrees of
Fechner suggested that the posterior chamber would be a myopia10-13.
safer option for phakic refractive lens8. After that, in vitro Indications for Phakic IOLs
studies showed that addition of small quantity of collagen Myopia, Hyperopia, Astigmatism, Presbyopia, Refractive
to HEMA enhanced the biocompatibility of the material. error after P.K., Severe anisometropia in children,
In 1993, Staar patented Implantable contact lens (ICL) Progressive anisometropia in pseudophakic children and
made of ‘collagen-copolymer’ or Collamer. It has 0.2% Combined – additive procedures such as in BIOPTICS.
porcine collagen, 63% poly-HEMA, 33% water and 3.4% For high myopia, -8.0 D to -20 D, stromal bed less than
benzophenone. Starting with a ‘soap bar’ model, its design 300 microns and post operative keratometry of less than 34
has evolved to present Visian 4c. The Phakic refractive lens D after LASIK form the general indications for pIOLs. The
(PRL), by CIBA vision was first designed as ‘mushroom’ FDA approved indications for Artisan are ---5.0 D to -20
lens by Drs. Zuev and Fyodorov in 1986. The iridocyclitis, D myopia, astigmatic correction of 2.5 D, age more than
night glare, loss of contrast sensitivity, endothelial loss and 21years and anterior chamber depth of more than 3.2 mm.
cataract etc. led on to evolution of its design to the present from the corneal surface. For ICL, the FDA has granted the
form. The PRL made of high refractive index silicon was approval of -3.0 D to -20D of myopia, astigmatism of 2.5
available for implantation in 1996 onwards9. D, age group of 21 years to 45 years and anterior chamber
Why do we alter the Normal Anatomy? depth of more than 3.0 mm from the corneal surface.
We put a pIOL over the crystalline lens to provide the For high hyperopias, the indications are hyperopia per se
following:- or keratometry more than 50 D after laser ablation. The
1) To achieve freedom from spectacles and/or contact available powers in pIOLs are up to + 20 D in ICL and up
to + 12 D in Artisan.
lenses. For astigmatism, Laser ablation is the treatment of choice,
2) To preserve accommodation in spite of surgery. up to 4 D to 5 D. However, pIOLs are available up to 6 D.
3) To reduce the surgical complications to a minimum The removability is an important consideration for both the
patient and the surgeon. Budo et al reported 79% of eyes
level. having a post operative spherical equivalent within +/- 1.00
Classification of pIOLs D14. Perez- Santonja et al reported the spherical equivalent
Anterior chamber pIOLs (AC pIOLs) of +/- 1.00 D in 91% 0f patients post operatively15.
Angle Supported For presbyopia, multifocal angle supported implants are
1. PMMA (Rigid) available. The central zone has -5.00 D to + 5.00 D. The
2. Foldable.
Iris – clawed
1. PMMA (Rigid)
2. Foldable.

Posterior Chamber pIOLs (PC pIOLs)
1. ICL ( collamer)
2. PRL (silicon)
Lasik Versus Phakic IOLs
The pIOLs have a potential to correct any ametropia,
including astigmatism. The powers of pIOLs do not depend

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intermediate zone has + 2.5 D and the peripheral zone instruments, pIOLs are explantable, there is no post
have the power for the distance vision. They are indicated operative decrease of contrast sensitivity and they provide
in the age group of 45 years to 65 years, the anterior more stable and predictable post operative refractive status.
chamber depth of 3.1 mm. from the surface of the cornea, Disadvantages of pIOLs
an open angle and the endothelial cell count of 2000/ mm2 All the risks of intraocular surgery accompany the
or more are required before implanting these lenses. 75% implantation of pIOLs. Large incisions were required for
of the patients had UCVA of 6/9 and near correction of N.8. the PMMA pIOLs but present pIOLs need incisions as small
The loss of one line in UCVA was attributed to decrease in as 2.8 mm. There is a limitation in the hyperopia due to
contrast sensitivity16. These lenses are not advisable for the small anterior segment. Corneal decompensation and
patients who drive at night due to possible haloes. endophthalmitis are still most dreaded complications.
The combined/additive procedures were started by Zaldivar Pre Operative Evaluation
et al in 1996. They named the procedure as bioptics17,18. The pre operative evaluation includes refraction and
It encompasses the procedures involving lasik, lasek and determination of power of pIOLs, obtained from
intracorneal rings with pIOLs. The recommended age by manufacturer or from the available nomograms. The
them was 19 years or more with spherical equivalent of diameter of the angle supported or sulcus supported pIOLs
-12 D or more in myopia and + 6 D or more in hyperopia. need to be accurately determined. The anterior chamber
The pIOLs were implanted at time duration of 2 days apart depth and corneal topography needs to be evaluated.
in both the eyes. The LASIK was done after three months Specular microscopy for the endothelial cell count and
of the pIOLs. It was ensured that there was stable refraction optic size in relation to the scotopic pupil size needs
and topography pattern in two readings taken one month to be determined. In addition to the above, all other
apart. The contraindications enumerated for this procedure investigations required for the routine cataract surgery need
include severe systemic illness, retinopathies, glaucoma, to be undertaken.
cataract, synechiae, keratoconus, infectious keratitis, Sizing of the pIOLs
moderate to severe dry eyes and thin corneas. For the angle supported pIOLs, 0.5 to1.0 mm is added to the
Preoperative Criterias for Phakic IOLs manually measured white to white diameter of the cornea.
Age more than 21 years, stable refraction for more than one The photos of anterior segment with Topographs may also
year, ammetropia not correctable with LASIK, unsatisfactory used for this. The LED sizer may also be used. Similarly,
vision or intolerance to spectacles and/or contact lenses, the ciliary sulcus diameter needs to be measured for the
open angles on gonoiscopy or more than 300 on anterior pc pIOLs. UBM and anterior segment OCT are also used
segment OCT, endothelial cell count of more than 2500/ to measure this. The pIOL must be implanted according to
mm2 if the age is more than 21 years and more than 2000/ the measured diameter only i.e. if the diameter is measured
mm2 if the age is more than 40 years, no pupillary or iris horizontally, it must be implanted horizontally only. If it is
anomaly and mesopic pupillary size less than 5.0 to 6.0 implanted vertically, it may cause decentration, pupillary
mm are the criteria to consider the patient for pIOLs. ovalization, iritis and glaucoma.
Anterior Chamber Depth Required from Corneal Angle Supported pIOLs
Endothelium Important surgical points
The anterior chamber depth measured from the endothelium Two days to one week prior to the implantation of these
is taken to be more accurate. The requirement for Acrysof PIOLs, two Argon-YAG peripheral iridotomies are done
phakic is more than 2.7 mm, for Artiisan – verisise is 2.7 between 10’O clock to 2’O clock location. 2.8mm to
mm, for Artiflex – veriflex is 2.7 mm, for ICL in myopia is 6.0mm incision is given temporally or superiorly after
2.8 mm, for ICL in hypermetropia is 3.0 mm and for PRL using topical, peribulbar or general anesthesia. The pIOL
is 2.5mm. is rarely dialed unless it is toric. The viscoelastic used is
Contraindications for Phakic IOLs meticulously irrigated and intracameral pilocarpine is used
Any intraocular pathology such as cataract, glaucoma, NVI to make the pupil central.
etc., decreased diameter of cornea, macular degeneration Posterior Chamber pIOLs
or any other abnormal retinal condition and any systemic Phakic Refractive Lens (PRL)
debilitating condition. It is made of optically clear silicon, is ultra thin and has
Advantages of Phakic IOLs a posterior base curve of 10.0 mm. radius. It mimics the
Range of correction with pIOLs is more than laser, it is
an easy technique, like cataract surgery, less expensive

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Figure 3: PRL (CIBA VISION) the upper lens is Figure 5: ICL V4C with Central KS Aquaport (Hole ICL)
for myopia and the lower for hyperopia
provides additional vault (0.13- 0.21mm). This allows fluid
Figure 4: A diagrammatic representation of in Situ exchange along the anterior lens capsule and prevents the
ICL (STAAR) contact with the anterior lens capsule. The latest model
Visian V4C has a central KS- Aquaport of 360 microns which
anterior curvature of crystalline lens. It is hydrophobic allows a more physiological exchange of the nutrients
in nature. The central thickness of less than 0.5 mm. is at the anterior lens capsule (Hole ICL). This reduces the
constant in myopic PRLs but varies in hyperopic PRLs. The anterior sub capsular cataract and need for post operative
edges of 0.2 mm. thickness are constant in hyperopic PRLs iridotomy. After six months of follow uo, 95% eyes were
but varies in myopic PRLs. The optic diameter of 4.5 to reported to be within + 0.5 D of targeted correction and
5.5 mm depending on the power is available. The power 100% were within +1.00 D of targeted correction22. The
range of - 3.0 D to – 20.0 D for myopia and + 3.0 d to change in manifest refraction was seen to be minimal and
+ 15 D in hyperopia is available. An incision of 3.2 mm no glaucoma or secondary cataract was seen.
with two side ports is used for implanting the PRL. Post Importance of Vault
operatively, it floats in the aqueous and does not exert The ‘vault’ is the space between the posterior surface of
any pressure on the crystalline lens. This prevents the post pIOL and the anterior lens capsule. A vault of less than
operative development of cataract. It rests on the zonules 0.25mm is considered to be ‘small’ and a vault of more than
and is unstable, so it is not a good option for astigmatic 0.75 mm is considered to be ‘excessive’. If the vault is high,
correction. it rubs against the iris, leading to chronic iritis and pigment
Implantable Collamer Lens (ICL) dispersion glaucoma. If the vault is shallow, it reduces the
Collamer attracts a monolayer deposition of fibronectin circulation of aqueous at the anterior lens capsule. This
on the surface. Model V2 and V3 had late anterior sub deprives the lens of the oxygen and nutrients thus leading
capsular opacities (5-30%) on one to three years of follow to cataract formation. The incidence of cataract in ac pIOLs
up19,20. Pupillary block and pigment dispersion glaucoma was 1.3% but in pc pIOLs it was seen to be 9.60%. After
were also seen21. The newer model V4 is a rectangular the ICL and PRL implantation, the cataract remained stable
model (Visian ICL V4), 7.5 to 8 mm wide, 11.5 to 13 mm for longer duration, so no significant reduction in vision
long with 0.5 mm increments. The optic diameter of 4.65 was seen.
to 5.5 mm in myopic ICL and 5.5 in hyperopic ICL are Complications
available. The powers available are -3.0 to -23 D in myopic The haloes and glare are the commonest complications.
and + 3.0 to + 22D in hyperopic ICLs. The optic zone is They are seen in up to twenty percent of the eyes. They are
less than 50 microns thick and footplates are 100 microns most prominent during the first post operative year and tend
thick. An incision of 3 mm is used for implantation using a to reduce with time. Pupil abnormalities like ovalization
microinjector. Steeper radius of curvature of the base curve are noted in 7 to 22 percent of cases. Iris retraction and
atrophy are seen in eyes with larger sized pIOLs. The
endothelial cell loss may be secondary to surgical trauma.
Up to seven percent loss of endothelial cells is reported
in the first year post operative period. The smaller size of
anterior chamber predisposes to more of endothelial cell
loss. The glaucoma may be transient due to retained visco-
elastic or may be due to papillary block. Uveitis may be
secondary to iris manipulation. In oversized pIOLs, chronic
iritis, PAS, iris atrophy and breakage of blood – aqueous

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Figure 6: In a patient of pellucid marginal degeneration, a relatively 4. Baikoff G. Intra ocular phakic implants in the anterior chamber. Int.
symmetrical bow- tie corneal topography pattern allowed 6/12 Ophthalmol. Clin. 2000; 40:223-35.

UCVA, after implantation of -11 D sph. +6 D cyl. at 250 toric ICL. 5. Perez – Santonja JJ, Alio JL, Jeminez- Alfaro I. et al. Surgical
correction of severe myopia with an angle- supported phakic intra
barrier may be seen. The cataracts may be seen more in pc ocular lens. J Cataract Refract Surg.2000; 26: 1288- 1303.
pIOLs than ac pIOLs. The cause may be trauma, uveitis and
small vault. Age more than 40 years and axial length more 6. Alio Jl, dela Hoz F, Ruiz-Moreno JM, et al. Cataract surgery in highly
than 30 mm are other predisposing factors for the formation myopic eyes corrected by phakic anterior angle supported lenses. J
of cataract. The incidence of retinal detachment in pIOLs, Cataract Refract. Surg. 2000; 26: 1303-11.
post operatively, has been documented to be between
3 to 5.5 percent. Whether they are additive risk is not 7. Fyodorov SN, Zuev VK, Aznabayev BM. Intra ocular correction of high
well documented. Other rarer complications are corneal myopia with negative posterior chamber lens. Ophthalmosurgery.
decomposition in the long term, Urrets – Zavalia syndrome, 1991; 3: 57-58.
malignant glaucoma, hyphema, endophthalmitis, epithelial
in growth and non specific diffuse intralemellar keratitis 8. Fechner PU, Strobel J, Wichmann W. Correction of myopia by
seen in bioptics, due to laser procedures. implantation of a concave Worst iris-claw lens into phakic eyes.
Ingenious use of pIOLs Refract. Corneal Surg. 1991; 7: 286-98.
The phakic IOLs have been used in the treatment of
children with severe myopic anisometropia, who resist and 9. Dimitrii DD, Kenneth JH, Aleksandra S. PRL- Medennium Posterior
do not co-operate in the traditional amblyopia treatment, chamber phakic intraocular lens. Refractive surgery with phakic
with very good results. IOLs. 2004; 12: 167 -78.
Conclusion
Though pIOL material, design and size are still evolving, 10. Seiler T, Koufola K, Richter G. Iatrogenic Keratectasia after laser in
yet, compared with corneal laser ablation, pIOLs are situ keratomileusis. J. Refract. Surg. 1998; 14: 312 – 17.
excellent in predictability, efficacy, safety and quality of
vision, at significantly lower financial inputs. 11. Seiler T, Quurke AW. Iatrogenic Keratectasia after LASIK in a case
References of forme frusta keratoconus. J. Cataract Refract. Surg.1998; 24: 1007
-09.
1. Kaufman and Kaufman. Phakic Intra ocular lenses – where are we
now? Refractive surgery with Phakic IOLs. 2004; 1: 5-12. 12. Pallikaris I, Kymonis G, Astryakakis N. Corneal Ectasia induced
by Laser in situ keratomileusis. J. Cataract Refract. Surg. 2001; 27:
2. Baikoff G. Phakic anterior chamber intra ocular lenses. Int. 1796–1802.
Ophthalmol. Clin. 1991; 31:75-86.
13. Spadea L, Palmieri G, Mosca L, et al. Iatrogenic keratectasia following
3. Baikoff G, Colin J. Intra ocular lenses in phakic patients. Ophthalmol. Laser in situ keratomileusis. J. Refract. Surg.2002 ; 18: 475–80.
Clin. North Am. 1992; 5: 789-95.
14. Budo C, Hesseloehl JC, Izak M et al. Multi center study of Artisan
Phakic intra ocular lens ; J. Cataract Refract. Surg. 2000 ; 26 : 1163–
71.

15. Perez – Santonja JJ, Bueno JL , Zato MA. Surgical correction of high
myopia in phakic eyes with Worst – Fechner myopia intra ocular
lens. J. Refract. Surg. 1997 ; 13 : 268 -81.

16. George D. Baikoff. The GBR/VIVARTE presbyopic foldable phakic
IOL. Refractive Surgery with Phakic IOLs. 2004; 15 : 207 -17.

17. Zaldivar R, Davidorf JM, Oscherow S, et al. Combined posterior
chamber phakic intra ocular lens and laser in situ keratomileusis:
Bioptics for extreme myopia. J. Refract Surg. 1999; 15: 299–308.

18. Zaldivar R, Oscherow S, Ricur G. The Bioptics Concept: Principles
and Techniques. Operative Techniques in cataract and Refractive
Sutgery. Vol. 3, 2000.

19. Sander DR, Vukich JA. Incidence of lens opacities and clinically
significant cataracts with implantable contact lens: Comparison
of two lens designs : The ICL in treatment of Myopia ( ITM) Study
group. J. Refract. Surg. 2002; 18 : 673–82.

20. Menezo JL, Peris _ Martinez C, et al. Rate of cataract formation in
343 highly myopic eyes after implantation of three types of phakic
intra ocular lenses. J. Refract. Surg. 2004 ; 20 : 317–24.

21. Kadjikian L, Gain P. et al. Malignant glaucoma induced by a phakic
posterior chamber intra ocular for myopia. J. Cataract Refract. Surg.
2002; 28: 2217–21.

22. Kimaya shimizu, Kazutaka kamiya et al. Early clinical outcomes
of implantation of posterior chamber phakic intra ocular lens
with a central hole (Hole ICL) for moderate to high myopia. Br. J.
Ophthalmol. 2012; 96: 406 – 12.

www. dosonline.org l 81

DOS Times Quiz Delhi
Ophthalmological
Society

Instructions:

1. Please return your answers to [email protected] or mail them to “The Quizmaster, DOS Times Quiz, Dr. Rajesh Sinha,
Room No. 479, Dr. R.P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi -

110029”. Please write your DOS membership number along with your answers.

2. The answers should reach not later than 30th September, 2014.

The quiz can also be viewed and directly answered on our website www.dosonline.org
3. The results will be announced at the DOS monthly clinical meeting on October 2014. The correct entry will be given a prize of

Rs. 2,500. If there are more than one correct entries, the winner of the prize will be decided by draw of lots.


Quiz compiled by Dr. Parul Jain

Match the following history and clinical signs (A-B) with the most likely diagnosis (A-N) listed below.

A. Schwartz’s syndrome H. posterior polymorphous dystrophy
B. carotid-cavernous fistula I. bulphthalmos
C. phacomorphic glaucoma J. malignant glaucoma
D. phacoanaphylactic glaucoma K. epithelial ingrowth
E. phacolytic glaucoma L. neurofibromatosis
F. iridocorneal endothelial syndrome M. Peter’s anomaly
G. iridoschisis N. Axenfeld’s syndrome

A. A 54 year-old man has a red right eye and decreased vision. On examination, he has a superior retinal detachment
and a mild anterior chamber inflammation. The intraocular pressure measures 32mmHg and responded poorly to
anti-glaucoma eye drops. Post-operatively, the intraocular pressure returns to normal spontaneously without further
treatment. Most likely diagnosis?

B. A 46 year-old man has bilateral glaucoma. Examination reveals peripheral anterior synechiae, corectopia and iris
atrophy in both eyes. In additions, there are band like lesions and islands of endothelial changes at the level of
Descemet’s membrane. Most likely diagnosis?

C. Which of the following tonometers is/are particularly useful with dense central corneal scarring or edema?
1. Mackay-marg
2. Goldman
3. Pneumotonometry
4. Perkins
D. What is the correct spot size for argon laser trabeculoplasty?

## ##

Membership No. __________ Name : _______________________Mobile No. _____________Email: _________________

Answer to DOS Times Quiz July 2014 B. ___________________________________________
A. __________________________________________ D. ___________________________________________
C. __________________________________________



Delhi
Ophthalmological
Society

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Category Name of The Mechanism of Duration Peak of Wash- Adverse Reactions Contra- Brand Name Anti-Glaucoma Medications
Prosta Drug Action of Action Action Out Indications
Glandins 12-24 hrs. 8-12 Period Ocular: Uveitic Ioprost,
Analogues Latanoprost: Increasing Travoprost hrs. 3-5 wks. Conjunctival glaucoma, Latochek,
0.005% one uveosacral - 40 hrs. hyperemia, burning, iritis, active or Latadrops,
Beta- drop HS outflow (sustained 2 hrs. 2-4 wks. stinging, elongation healed herpes Xalatan, 9 PM
Adrenergic Travoprost: (remodeling of effect on and darkening of simplex keratitis, Travo,
Antagonist 0.004% OD extra-cellular nocturnal eye lashes, induced immediate Travatan,
Bimatoprost: matrix), IOP) iris darkening, post-op period, Optivo,
0.03% OD Bimatoprost Periocular skin patients with risk Lupitros
(Prostamide) also increases 12-24 hrs. pigmentation factors for CME Careprost,
Tafluprost: trabecular (Irreversible- like (aphakia, Intraprost,
0.0015% OD outflow (better Caution with pseudophakia), Lumigan,
(FDA approved for those poorly uniocular patients). hypersensitivity, Bitoma
in 2012) responding to Less common but pregnant or Saflutan,
Latanoprost) severe-Iris cysts, nursing mothers. Zioptan
anterior uveitis,
Non- Timolol: 0.25% Reducing CME, reactivation Bronchial Iotim,
selective - 0.5% BD aqueous humor of herpes simplex asthma, COPD, Ocutim,
production by keratitis. heart block, Glucomol,
Levobunolol: acting on b2 Systemic: Excellent recent MI, Lopress,
0.5% OD receptors on the systemic safety Congestive Glutim,
nonpigmented profile. Heart Failure, Timoptic,
Carteolol: 1%, epithelium layer Ocular: Conjuctival depression, Betimol
2% of the ciliary hyperemia, ptosis(induces Betagan,
body. Superficial punctate muscle Vistagan
Betaxolol: 0.5% keratitis, corneal weakness). Ocupress,
BD anaesthesia, dry Teoptic,
eye, anterior uveitis Arteolol,
www. dosonline.org l 91 (metipranolol-not Glauteolol Tearsheet
used now). Optipress,
Systemic: Betapress,
Cardiovascular Iobet,
(bradycardia, Betoptic
exercise intolerance,
hypotension,
worsening of
CHF, heart block),
pulmonary
(bronchospasm,
aggravated COPD),
CNS(Depression,
impotence),
delayed response to
hypoglycemia.

Category Name of The Mechanism of Duration Peak of Wash- Adverse Reactions Contra- Brand Name
Drug Action of Action Action Out Indications
Period
Tearsheet
Adrenergic Non- Dipivefrin Act first by 12-24 hr. 1-4 hrs. 1-3 wks. Ocular: Hyperemia, Cerebral and
92 l DOS Times - Vol. 20, No. 1 July, 2014Agonistsselective0.1% andreducing1.5-2 1-3 days blurred vision, coronary
Alpha2 Epinephrine aqueous hrs. follicular insufficiency,
agonist (not available) production conjunctivitis, patients on Iopidine
Apraclonidine: and later by upper lid retraction MAO inhibitors, Iopidine,
0.5%-1% decreasing and mydriasis (due children (as Brimochek,
Brimonidine: outflow facility. to cross reactivity they cross the Brimonidin
0.2% BD or Brimonidine- with alpha1 blood-brain P, Alphagan
TDS (neuroprotection- receptors in Muller barrier-causes P, Brimosun,
reduces loss muscle and iris CNS depression), Iobrim,
of retinal sphincter muscle), Risky jobs Rimonid
ganglion cells, conjunctival (drowsiness)-
also increases blanching, topical pilots, drivers, Isopto
uveoscleral allergy, Brimonidine depression, Carpine,
outflow) with Purite as cystoids macular Pilocar,
the preservative edema (contra- Locarp
Cholinergic Pilocarpine: Increases 4-8 hrs. (Alphagan-P)- indicated in Phospholine
Agents 1%, 2%, trabecular less allergy, FDA aphakes) Iodide,
4% QID, meshwork approved. Chronic Miochol E
pilocarpine outflow by acting Systemic: Sedation, anterior uveitis, (obtain rapid
gel 4% OD on M3 receptor drowsiness. rubeosis iridis, miosis afer
before bed in ciliary body Ocular: Brow developmental delivery
time, ocusert (traction on ache, transient glaucoma, PAS/ of lens in
P-20/ P-40 scleral spur), myopia, retinal membrane cataract
(membrane- decreases detachment (no covering angle surgery, in
controlled uveosacral definite cause and (because it iridectomy ,
delivery system) outflow, miotic effect relationship), decreases in penetrating
effect- ?used in cataract, breakdown uveosacral keratoplasty)
Echothiophate: management of of blood aqueous outflow), relative Miostat,
0.03%, 0.06%, acute attack of barrier, in extremely contraindication Carbostat,
0.125%, 0.25% angle closure shallow peripheral in young
anterior chamber individuals (due
Anti- Carbachol: glaucoma due to angle- paradoxical to brow-ache,
cholineste 0.75%-3% BD/ relative pupillary rise in IOP due to induced myopia)
increase in anterior-
rase TDS block. posterior diameter
of the lens and
reduction of anterior
chamber angle
depth.

Category Name of The Mechanism of Duration Peak of Wash- Adverse Reactions Contra- Brand Name
Drug Action of Action Action Out Indications
Period

Systemic: Cicatricial Carboptic,
pemphigoid, Isopto-
hypersensitivity, carbachol
stimulation of
glands, contraction
of smooth
muscles: increased
perspiration,
nausea, vomiting,
diarrhea, polyuria,
bronchospasm,
3rd degree AV
block, cognitive
dysfunction. Antidote
- Atropine.

Carbonic Oral Methazolamide: Decreases 8-12 hrs. 2-6 hrs. 2 days Systemic: Hypersensitivity Diamox,
Anhydrase 25mg, 50mg, aqueous humor (oral), Paresthesias of to sulfonamides, Iopar-SR,
Inhibitors 100mg BD/TDS production by fingers, toes and decompensated Actamid,
Acetazolamide: Inhibiting ion 1 wk around mouth, cornea (with Synomax
250 mg every transport (inhibits (topical) urinary frequency, dorzolamide),
6 hrs or 500 net chloride flux
mg sustained across ciliary metabolic acidosis, avoided in Trusopt
release capsules epithelium) and fatigue, wt loss, sickle cell
BD. Children increases ocular anorexia, depression, patients. Asopt
– 5-10 mg/kg blood flow decreased libido,
every 4 to 6 hrs GI symptoms, renal
calculi, sulfonamide
related reactions
TearsheetTopicalDorzolamide– maculopapular
2% and & urticarial skin
93 l DOS Times - Vol. 20, No. 1 July, 2014Brinzolamide eruptions, Stevens -
1% BD/TDS Johnson syndrome,
teratogenic.

Ocular: Ciliary body
edema- may lead
to angle closure
glaucoma.

Category Name of The Mechanism of Duration Peak of Wash- Adverse Reactions Contra- Brand Name
Drug Action of Action Action Out Indications
Period
Tearsheet
Ocular: Irritation,
94 l DOS Times - Vol. 20, No. 1 July, 2014 transient blurred
vision, periorbital
Hyper- Glycerol: 1-1.5 Reduces vitreous 5 hrs. 30 min. dermatitis, corneal Readily
Osmotic g/kg of BW of a volume due 2-6 hrs. 20-60 decompensation in metabolized -
Agents 50% soln to an osmotic min. susceptible eyes. relatively safe
Mannitol: 2g/kg gradient between Systemic: but is relatively
of BW of 20% the blood and Bitter taste, contraindicated
soln ocular tissues Thrombocytopenia, in diabetes as it
which pulls fluid Erythema can easily upset
from the eye multiforme glucose control
Systemic: Vomiting, Rapidly excreted
Diuresis esp unchanged
with iv (Urinary in the urine-
retention and severe contraindicated
bladder distension in renal disease,
in men with congestive
BHP), headache heart failure
and confusion (causes volume
(due to cerebral overload)
dehydration),
hyponatremia,
hypokalemia,
congestive
heart failure,
hypersensitivity

Combination Therapy: Single bottle, improved efficacy, convenience, good compliance, reduced cost. • LATOCHEK T, LATACOM, LATIM, XALACOM
(Latanoprost+Timolol) • CAREPROST, GANFORT (Bimatoprost+Timolol) • TRAVACOM, DUOTRAV (Travoprost+Timolol) • BRIMOLOL, COMBIGAN,
ABPRESS (Brimonidine+Timolol) • COSOPT, MISOPT, DORZOX-T, OCUDOR-T (Dorzolamide+Timolol) • AZARGA (Brinzolamide+Timolol) • FOTIL
(Pilocarpine+Timolol) • SIMBRINZA (Brinzolamide+Brimonidine tartarate) • CARPILO (Carteolol+Pilocarpine) • BI-MIOTIC (Physostigmine+Pilocarpine
nitrate) • Preservative Free: Ocudose (Iotim), Travatan Z, Cosopt PF (dorzolamide+timolol), Saflutan/Zioptan (Tafluprost), Trusopt (Dorzolamide), Cosopt
(Brinzolamide).

Nalini Saxena MBBS, Supriya Arora MS, Prateeksha Sharma Nalini Saxena MBBS
MBBS, Usha Kaul Raina MD, FRCS, FRCophth

Guru Nanak Eye Centre, New Delhi