Glaucoma

1. Surgeries in open angle glaucoma
Presenter: Dr.Aditi Singh

2. Indications:
1.Documented visual field and optic nerve damage, despite maximum
tolerated medications and laser therapy.
2. Anticipated progressive damage or intolerably high IOP.
3. Combined with cataract procedure if there is borderline IOP control or
advanced damage,.

3. :
guarded (trabeculectomy)
Penetrating filterationg surgeries
full-thickness
Nonpenetrating filtration surgery(NPFS)
Glaucoma Drainage Devices (GDD)
Recent advances in glaucoma surgeries

4. Full-Thickness Filtration Procedures
1.Thermal sclerostomy (scheie Procedure).
2.Sclerectomy
3.Trephination
4.Iridencleisis
Rarely performed today.

5. 1.Thermal sclerostomy (scheie Procedure):
• Limbal-based conjunctival flap.
• Light cautery applied to the sclera in 1X 5 mm area , behind
corneolimbal junction.
• 5 mm limbal scratch incision is made through the cauterized area.
• Cautery is applied to the lips of the incision , until the wound edges
separate by atleast 1 mm.

6. 2. Sclerectomy:
Posterior lip sclerectomy:
• Ab-externo incision- just behind the point of reflection (using a limbal-
• based flap) of the conjunctiva at the anterior limbus.
• Length - 3–4 mm
• Sclerectomy - 1-mm scleral punch
• Peripheral iridectomy
• Closure
Anterior lip sclerectomy:
• Incision - at the corneoscleral sulcus
• Excise the 1-mm semicircle of tissue.
• Button holing of the conjunctival flap .

7. • 3.Trephination:
• Corneoscleral trephination, using a 1–2-mm glaucoma trephine, is a
difficult procedure.
• Performed only occasionally.
4.Iridencleisis:
• Wedge of iris is incarcerated into the limbal tissue . The presumed
mechanism was a ‘wicking’ of aqueous by the iris tissue.
• However, reports of chronic iritis, infection, and sympathetic
ophthalmia led to other techniques being explored

8. Complications:
• Shallow (or flat) anterior chambers:
• Peripheral anterior synichae,
• Corneal decompensation.
• Premature cataract formation,
• and infections.

9. Guarded Filtration Procedure:
Trabeculectomy :
Introduced by: Cairns in the 1960s.
Indications:
• Intraocular pressure too high to prevent further glaucoma damage and
• functional visual loss.
• Documented progression of glaucoma damage at current level of intraocular
• pressure with treatment.
• Presumed rapid rate of progression of glaucoma damage without
intervention.
• Poor compliance with medical therapy: cost, inconvenience, understanding of
• disease, refusal.
• Intolerance to medical therapy due to side effects.
•

10. Anesthesia
• General anesthesia
• Local : Retrobulbar local block,
peribulbar block ,
subtenon’s, or
• Topical anesthesia in selected cases.

11. Technique Clear corneal traction suture:
•7-0/ 8-0 vicryl
• half thickness
• 2 mm anterior to the limbus.
The Conjunctival Flap:
Site: Superior and slightly nasal.
Both limbus and fornix based conjunctival flaps

12. Limbus-Based Flap
 Advantages:
• allows tight wound closure.
• relatively easy to master.
 Disadvantages:
• ‘migrates’ towards the limbus.
• more chances of incapsulated
bleb.
Fornix-Based Flap
 Advantages:
• easier exposure of the surgical site
• reduced handling of the
conjunctival flap.
 Disadvantages:
• longer operative time.
• may leak in the postoperative
period and fail to retain aqueous,
so that the bleb flattens.

14. Antimetabolites :
Agents
5-FU inhibits DNA synthesis and RNA function; usual intraoperative
dose is 50 mg/mL.
MMC alkylates DNA and inhibits DNA and RNA synthesis; usual dose is
0.2–0.4 mg/mL.
Prepare sponges: cut to size and then soaked in the antimetabolite
Place sponge under the conjunctival flap (and under scleral flap in
resistant cases) for appropriate duration (5 min for 5-FU; 2–4 min for
MMC)

15. Scleral
Flap

16. The anterior chamber is entered under the flap, and a block of tissue
approximately 1.5–2.5 mm wide is removed with a Descemet’s punch just
anterior to the scleral spur.
Removal of the trabeculectomy block too posterior to the scleral spur offers no
advantage and increases the risk of hemorrhage
Peripheral iridectomy.

17. Flap Suturing
The scleral flap is reapproximated with 9-0 or 10-0 nylon sutures .
Releasable suture
Peng Khaw’s adjustable suture technique allows a titrated outflow
A careful running suture in two
layers, first closing Tenon’s and
then its overlying conjunctiva at
the limbus.

18. Postoperative lasering, adjustment, or release of sutures :
Argon green, argon blue-green, diode, YAG laser or krypton red laser.
Four-mirror Zeiss gonioprism or with the Hoskins laser suture lens .
High-magnification suture lysis contact lenses are commercially available
(e.g., Mandlekorn lens or Blumenthal lens )

19. Complications and management:
Complications
Intra-operative Post-operative
Early Late

20. Intraoperative Complications
Preoperatively:
Identify the risk factors.
Conjunctival button
Discontinuation of anticoagulants.
Intraoperatively:
Topical apraclonidine 1 % or adrenaline
Minimal handling of tissues
Maintain intraoperative IOP.
Management :
All wounds should be promptly closed
Reformation of the anterior chamber
SCH extensive: drainage of blood by
• Choroidal hole
expansion: secure the wound;
Perform posterior Scleral sclerotomy flap damage
that
does not perforate choroid ,
Vitreous loss
administer atropine.
• Suprachoroidal hemorrhage:Recognize
vitreous loss; secure the wound; perform
posterior sclerotomy over choroidal
elevation area to drain blood;
administer atropine
Bleeding:Conjunctiva,
sclera,iris or
suprachoroidal
Flat anterior chamber:choroidal
hemorrhage , choroidal
expansion,aqueous misdirection
Prevention: non toothed forceps
Before or after sclerostomy
Management:
small : spontaneous healing (with hold steroid drops)
focal (1-2mm) : closure with 10-0 nylon
Management:
Before sclerostomy: new site
After sclerostomy :
Minor : suturing with 10-0 nylon
Severe : scleral patch graft , tenon’s capsule ,
fascia lata
Causes: thin sclera( buphthalmic eye), aphakia,
post trauma, lens dislocation.
Management : anterior vitrectomy
emergency
pars plana sclerostomy

21. Postoperative complications
Early
Shallow AC
Low IOP High IOP
Early
Infection
Wipe out phenomenon
Blebitis Endophthalmitis

22. Shallow AC
Low IOP
Formed Bleb Flat Bleb
Over filtration
Causes:
•Antimetabolites
•Loose sceral flap
sutures
•Full thickness
procedures
Management :
•Cycloplegics
•+/- aqueous suppressants
•Decrease steroids
•Pressure patching
•Simmons shell, SCL
Flat AC:
•Reformation :
•Visoelastics / BSS
•Large choroidal effusions
may need drainage

23. Shallow AC
Low IOP
Flat Bleb
Pressure patch Wound Leak
Temporary tapering of topical steroids
Large diameter SCL
Cyanoacrylate Glue
Injection of autologous blood
Surgical repair (larger holes)
Conjunctival autograft
Indian J Ophthalmol. 2011 January; 59

24. Shallow AC
Low IOP
Serous choroidal detachment
•Due to Hypotony
•Prolongs the
hypotony
•Vicious cycle
Management :
•Cycloplegics , topical steroids
•Surgery :
•Kissing choroidals
•Flat AC , compromised cornea
•Eyes with chronic angle closure
glaucoma with extremely shallow
AC, after trabeculectomy
Dellaporta Technique

25. Low IOP
CB Shutdown
• Excessive inflammation
Steroids
Atropine
Cyclodialysis
cleft
• Identify with gonio or UBM
• Atropine, decrease steroids
• Argon laser with Goldmann lens
• Avoid beta blockers, CAI inhibitors
• Treat the scleral region of the cleft
• For large cleft, definitive management is surgical
repair

26. Shallow AC
High IOP
Pupillary block
Suprachoroidal
heamorrhage
Malignant glauma
• Non patent PI
• Management:
• Dark choroidal swelling
• Typical symptoms:
• sudden loss of vision
Laser PI
Mydriasis
Topical steroids
pain
nausea and/or vomiting
• Very shallow or flat central AC
• Look for patent iridotomy
• Aqueous suppressants
• Cycloplegics, topical steroids
• YAG anterior vitreous face
(aphakic/pseudophakic)
• Pars plana vitrectomy
• Vigorous surveillance
• Attention to the fellow eye.
• Diagnosis
• Indirect
• B-scan
• Management
• Aqueous suppressants,
• Hyperosmotics ,Pain relief,
• Drainage

27. • Filtration failure:
• Obstruction of the sclerostomy and scleral flap may be internal
(incarceration of iris, ciliary processes, or vitreous), scleral (fibrin, blood),
• or external (overly tight scleral flap sutures).
• Consider bleb massage, removal of releasable suture(s), loosening of
adjustable suture(s), and argon laser lysis of fixed suture(s).
• Visual loss:
• Wipe-out of the remaining field may occur in the presence of a vulnerable
optic nerve (associated with increased IOP or hypotony) or
• Hypotonous changes may lead to reduced acuity (e.g., from maculopathy).

29. Infection
Blebitis : - a painful red eye, possibly with mucus discharge and photophobia.
The bleb is milky with loculations of pus, conjunctival injection (especially around the
bleb), and increasing IOP.
Identify organism with culture/swab of bleb.
Treat with intensive topical antibiotics and systemic antibiotics.
Consider addition of topical steroids after 24 hours and add mydriatic if AC activity is
present.

30. Endophthalmitis:
Clinical features c
are the same as for blebitis but are more severe, with
decreased VA and vitritis.
Investigate and treat as for other postoperative endophthalmitis.
However, endophthalmitis occurring after trabeculectomy tends to
run a more aggressive course with a worse prognosis than after
cataract surgery.

31. Late postoperative complications
a)Leaking bleb: antimetabolite-associated or nonguarded filtration
surgery
Small leaks : often resolves
Otherwise, : consider bandage contact lens, autologous blood injection,
compression sutures, or refashioning of bleb.
b)Infection: (blebitis/endophthalmitis).
c)Visual loss: Cataract .There can also be induced astigmatism,
maculopathy, and glaucomatous progression.

32. Failure of the Filtering Bleb:
Early Failure of Filtering Bleb:
Presentation: high IOP, deep anterior chamber, and low and hyperemic bleb.
Preventive measures:
Postoperative topical steroids are routinely used.
The use of antifibrotic agents.
Manoeuvres to improve bleb function:
Digital ocular compression and focal compression
Laser suture lysis or removal of an externalized releasable suture

33. Late Failure of Filtering Bleb:
Most common cause : subconjunctival-episcleral fibrosis .
Factors accelerating fibrosis are:
black race, childhood, postoperative subconjunctival hemorrhage, the
presence of reactive sutures, and inflammation.
“Warning signs ” - increased bleb vascularization, bleb inflammation,
and/or bleb thickening, high IOP.
Treatment :
In cases of subconjunctival-episcleral fibrosis - an external revision or bleb
needling can be tried along with antimetabolites.

34. Encapsulated Blebs:
Localized, elevated, and tense filtering blebs, with vascular engorgement of
the overlying conjunctiva and a thick connective tissue
Tenon’s cyst
Second to fourth postoperative week as a tense, “tight-appearing”bleb.
Temporary IOP reduction : aqueous suppressants .
Bleb needling with antimetabolites is an option in case of sustained raised IOP.
Failing all measures, a surgical bleb revision (partial/ complete cyst excision) or
repeat trabeculectomy may be required, especially in cases of multiloculated cysts.

35. Other bleb related complications:

36. Complications….
Cataract: flat anterior chamber
reformation of the anterior chamber with air
lens trauma
inflammation
the use of – steroids , intraoperative MMC
Ptosis : superior rectus bridle suture
MMC
damage to superior rectus.
Astigmatism: large scleral flaps.
radial flap sutures.

37. Glaucoma Drainage Devices
Indications:
• Failed trabeculectomy
• Extensive conjunctival scarring
• Likely failure of trabeculectomy, including -
• Neovascular glaucoma
• Uveitic glaucoma
• Glaucoma associated with penetrating keratoplasty
• ICE syndrome
• Epithelial downgrowth
• Refractory pediatric glaucoma

38. Valved
Two main classifications of implants
• Only drains fluid at a certain
IOP.
• Valve opens and fluid is
drained into a reservoir where
it is absorbed by surrounding
tissues(e.g., Krupin or Ahmed
valves).
Non- Valved
• Nonvalved implants or open tube
drainage devices provide little
resistance to aqueous flow during the
early postoperative period until a
fibrous capsule forms around the
plate.(e.g., Molteno or Baerveldt
implants).

39. RESERVOIR PLACEMENT
• The scleral bed is exposed with a fornix-based conjunctival flap.
• Superior quadrant (supero temporal quadrant) is preferred.
• All plates have eyelets on the anterior edge for securing the
implant to the sclera with a non-absorbable (suture#6-0 Mersilene ).
• The plate should be positioned posterior to the insertion of the rectus
muscles; 8–10 mm is measured with calipers from the limbus to the
central plate edge.

40. TUBE ENTRY.
 The tube is trimmed so that there is a bevel facing anteriorly and 2 to 3
mm will appear within the anterior chamber .
• After scrutiny for the ideal tube entry site, a 23-gauge needle is passed
through the limbus to create a tight entry site. The tube tip should not be
touching either the cornea or lens.
• Tube is secured to sclera using 9-0/10-0 nylon suture.

41. WOUND CLOSURE
 Some surgeons construct a scleral tunnel to cover the tube.
 Usually the tube is covered with some sterile biodegradable tissue, such as
donor sclera, pericardium, or dura, all of which seem to be equally
efficacious.
 The conjunctiva is repositioned to carefully cover the tube and overlying
patch graft.

42. Modifications
• To avoid overfiltration and hypotony in the early postoperative period, a
two-stage implantation or temporary ligation of the tube may be utilized.
• Two-stage implantation:
• Tube is folded back and placed under the patch graft or beneath an adjacent
rectus muscle and can be attached to the episclera with a nylon or silk suture
to facilitate identification.
• In the second stage, the tube is inserted 4–6 weeks later after a fibrous
capsule (pseudocyst) has formed around the plate.

43. Modifications…….
• Transient flow restriction techniques :
• Aqueous flow can be limited in the early postoperative period by internal
and external occlusion techniques.
Rip-cord suture
Prolene suture ligature at tip of tube

44. Complications
Excessive drainage : leakage around or down the tube if the occluding suture
is loose and results in hypotony and a shallow anterior chamber.
Malposition : endothelial or lenticular touch .
Tube erosion : through the sclera and conjunctiva .
Early drainage failure : blockage of the end of the tube by vitreous, blood or
iris tissue .
Late drainage failure : Excessively thick fibrous capsule.
Indian J Ophthalmol. 2011 January; 59

45. Complications………….
 Diplopia: mechanical involvement of the superior oblique muscle if the
implant impinges on the superonasal quadrant, or to the elevated space-occupying
bleb that can form over the plate, causing restriction and
muscular limitation.

46. NONPENETRATING GLAUMA SURGERY(NPGS)
Indications
1.All open-angle glaucomas (especially if):
 Early surgical intervention required.
 Monocular patient.
 Large diurnal fluctuations .
2.High risk of choroidal effusions or hemorrhages.
3.High risk of postoperative hypotony.
4.Uveitic glaucoma without extensive PAS.
5.Congenital glaucoma.

47. NPGS
Deep Sclerectomy Viscocanalostomy

48. Deep sclerectomy:
The superficial scleral flap is one-third of the
scleral thickness and is dissected 1--1.5 mm
into clear cornea.
The sclera is exposed and a superficial scleral
flap measuring 5 5 mm is dissected, including
one-third of the scleral thickness
The When deep the sclerectomy anterior dissection measures is 4 completed, 4 mm and the
sclera is
dissected, deep scleral leaving flap about is removed 5% of by sclera cutting over anteriorly the choroid
first
and with ciliary the diamond body.
blade.
The inner wall of the Sclemm’s canal and the
juxtacanalicular trabeculum are peeled off using fine
forceps.
TThhee A collagen s Sclcehrolceomrnmea’lsdciassnecatli implant is oins sutured iisd pernotloifniegded. in the anteriorly scleral
1--1.5
mm bed.
using a ruby blade or a crescent knife, in order to
remove the sclerocorneal tissue behind the anterior
trabeculum and Descemet’s membrane.
Surv Ophthalmol 53 (6) November--December 2008

49. Viscocanalostomy
After excision of the deep tissue containing a portion of
Schlemm’s canal, the remainder of Schlemm’s canal can be
accessed by inserting
a fine-tipped cannula into the exposed ostia of Schlemm’s
canal.
Injection of viscoelastic material into Schlemm’s .
Repeated 6-7 times.
Injection of viscoelastic beneath the superficial scleral flap.
Suture the superficial scleral flap tightly.

50. Advantages Disadvantages
 No sudden decompression of anterior
chamber
 Suprachoroidal hemorrhage less likely
 Serous choroidal detachment less likely
 Reduced risk of prolonged hypotony
 Less likely to get filtering bleb
 Less chance of bleb leak – early or late
 Less chance of blebitis, endophthalmitis
 Contact lens wear less likely to be problematic
 Bleb dysthesia rare
 Less intraocular inflammation
 Less chance of intraocular bleeding
 More rapid visual rehabilitation
postoperatively
 Technically more difficult.
 Takes longer in the operating room
 Requires some specialized
instrumentation.
 About 10% have actual perforation into
anterior chamber requiring iridectomy.
 Intraocular pressure less likely to be
lowered sufficiently in advanced
glaucoma.
 Pressure lowering may not last as long
 It is important to remember that these
procedures are in evolution and
refinements are necessary.

51. Complications of deep sclerectomy
 Conversion to trabeculectomy because of penetration
through trabecular meshwork.
 Scleral ectasia.
 Iris incarceration, prolapse or peripheral anterior
synechiae.
 Descemet’s detachment.
 Hypotony.
 Hyphema.
 Serous choroidal detachment.
 Vitreous hemorrhage.
 Late anterior chamber bleeding during gonioscopy.

52. Contraindications:
1.Trabecular meshwork obstructed:
• Extensive synicheal angle closure.
• Neovascular glaucoma.
• Occludable angle.
2.Altered anatomy:
• Thin sclera.
• Significant limbal scarring.
3. Post laser trabeculoplasty.
4.Angle recession glaucoma.

53. Recent advances in glaucoma surgeries
I. The Ex-Press mini glaucoma shunt
II.Nonpenetrating Ab Externo Schlemm’s Canaloplasty
III.Ab Interno Devices: The Trabectome and Micro-bypass Stent
IV.The Gold Microshunt: A Suprachoroidal Device

54. The Ex-Press mini glaucoma shunt
Originally developed to be implanted
subconjunctivally through the limbus
Redesigned - trabeculectomy style scleral flap.
Long term success – yet to be established.

55. Canaloplasty
Nonpenetrating Ab Externo Schlemm’s Canaloplasty

56. Once the A Secnhtlierme 10–0 Prolene tmchie’rs ctcruaamnbaefcle suture uirsl eoendxepcseoc seoemfd is tied e twthietwh around ci naad ncorawels c(hTeanDstW the bbl)ea end ecdnaen c baen of sneeunla. the device
ted with
the iScience prior microcatheter, to its retraction.
the device is primed with ophthalmic
viscosurgical device, which can be seen emerging from the tip of the
device on the right.
A superficial Deeper spcalerraabloflliacp f lias pc roefa atepdp rwoixthim salitgehlyt l2y5 s0m- atoll e3r0 d0i-m2men tshiiocnksn tehssa,n 4 t.5h a t4 .5 mm, is made.
Once the suture has been delivered and cut away from the
microcatheter, the two cut ends must be matched and tied
together.
of the superficial flap.
•The superficial scleral flap is then placed back into position and sutured interrupted 10–0
nylon sutures.
• High viscosity sodium hyaluronate is then injected under the superficial scleral flap using the
viscocanalostomy cannula in order to maintain the scleral lake – the space where aqueous
humor that has percolated through the TDW accumulates and is then absorbed into episcleral,
scleral, and choroidal circulation.
• The conjunctiva is then closed with a 10–0 Vicryl suture.
Techniques in Ophthalmology 5(3):102–106, 2007

57. Advantages: Drawbacks:
• Absence of vision-threatening
complications such as:
• Choroidal detachments,
• Shallow or collapsed anterior
chambers, and
• Prolonged hypotensive
periods.
 Descemet’s tear.
 Elevated postoperative pressure
( possible inflammatory changes in
the canalicular structures).
 Difficult procedure, which needs an
experienced deep sclerectomy or
viscocanalostomy surgeon.

58. Shunts into
schlemm’s
canal
The
Trabectome
Micro-bypass
Stent

59. and
Micro-bypass
Stent

60. •A clear corneal near-limbal 1.6-mm keratome incision is made. Viscoelastic may or may not be necessary to allow
safe insertion of the instrument tip to allow infusion flow and anterior chamber stability.
•Surgical tip is advanced under gonioscopic control to engage nasal meshwork before activating aspiration and
ablation by progressively depressing the foot pedal and rotating the tip parallel to the iris just anterior to the scleral
spur.
•Ablation with continual infusion and aspiration is performed along an arc of 30 ° to 60°.
Microelectrocautery handpiece designed to ablate trabecular meshwork and
Schlemm’s canal inner wall tissue over an area of several clock hours..
The device is a disposable handpiece that is activated by foot pedal control
connected to a console that allows the surgeon to adjust infusion, aspiration, and
dissipated electrosurgical energy.
Trans Am Ophthalmol Soc v.104; Dec 2006

62. Two functions: 1. providing direct access of
aqueous into the schlemm’s from the anterior
chamber (the snorkel effect) and
2. pushing the anterior trabecular meshwork
away from the posterior wall of Schlemm’s canal.

64. Arch Ophthalmol. 2009;127(3):264-269.
The Gold Microshunt: A Suprachoroidal
Device

65. Arch Ophthalmol. 2009;127(3):264-269.
Postoperative clinical image of a patient after Gold Micro Shunt implantation.
Note the good position of the shunt in the anterior chamber (A), with no shunt-corneal
or shunt-iris touching, as seen in the gonioscopic view (B).

66. Endoscopic Cyclophotocoagulation :
Indications:
•In cases of refractory glaucoma
•Patients on maximum medical
therapy showing continued
progression of disease were often
considered as appropriate
candidates.
•Patients who had failed filtration
surgery or were considered at high
risk for failure or complications
post-traditional filtration
procedures.
•Better visualization of the tissue being treated
•Less destructive method of applying the laser,

67. ECP employs -
810-nm diode laser, allows
the
surgeon to precisely aim
and deploy
the laser to cause effective
cycloablation while avoiding
damage to adjacent
structures.
Extensive contraction of the
ciliary processes was
observed as well as
changes to the ciliary body
epithelium.
There was much less
destruction (if any) to the
ciliary body muscle

68. Procedures of historical importance:
 Cyclodialysis was once a mainstay in the management of aphakic glaucoma. Its
principle was to mechanically disrupt the iris root at its scleral spur
attachment so that a cleft was created between the anterior chamber and
suprachoroidal space.
 Significant hemorrhage was almost unavoidable, as was hypotony resulting
from an overfunctioning cleft, which if spontaneously healed would lead to a
precipitous rise in IOP.
 Other common complications included cataract and stripping of Descemet’s
membrane. With so many more physiologic options for surgical control of the
IOP, this procedure is now of historical relevance only.

69. References
1.Becker-Shaffer's Diagnosis and Therapy of the Glaucomas, 8e Robert L.
Stamper MD , Marc F. Lieberman MD , Michael V. Drake MD
2. Shields Textbook of Glaucoma (Allingham, Shields' Textbook of
Glaucoma) Karim F. Damji , Sharon Freedman , Sayoko E. Moroi (Editor), M.
Bruce Shields.
3. Kanski's Clinical Opthalmology: A Systematic Approach 6th Ed .Mohd
Zafrullan Zamberi Ophthalmology.
4. Oxford American Handbook of Ophthalmology. James C. Tsai, MD, MBA.
5. The glaucomas: concepts and fundamentals.Tarek M. Eid ,George L.
Spaeth.
6. The Glaucoma Book A Practical, Evidence-Based Approach to Patient Care
Editors
Paul N. Schacknow , John R. Samples
7. Yanoff & Duker: Ophthalmology, 3rd
8. The role of artificial drainage devices in glaucoma surgery(Indian Journal of
Ophtahlmology.)1998(46):1,41-46.R Thomas, A Braganza, G
Chandrasekhar, S Honavar, AK Mandal, R Ramakrishnan, BS Rao, R
Sihota, NN Sood, B Shantha, L Vijaya .Christian Medical College, Vellore,
Chennai, India.
9. Nonpenetrating Glaucoma Surgery.Efstratios Mendrinos, Andre´ Mermoud,