A surgical procedure featuring a partial thickness scleral flap that creates a fistula between AC and subconjunctival space for filtration of aqueous and creation of conjunctival bleb in an effort to lower IOP

1. M O D E R AT O R – D R . S H I VAY O G I R
K U S A G U R
P R E S E N T O R – D R . S A D H W I N I M H
TRABECULECTOMY

2. FILTRATION SURGERIES
Full thickness Partial thickness Non-penetrating
Sclerectomy Trabeculetomy Sinusotomy
Iridencleisis Ab externo
trabeculectomy
Trephination Deep sclerectomy
Thermal sclerostomy Viscocanalostomy
Laser sclerostomy
• Louis de Wecker – father of glaucoma filtering surgery

3. INTRODUCTION
• A surgical procedure featuring a partial thickness scleral
flap that creates a fistula between anterior chamber and
subconjunctival space for filtration of aqueous and
creation of conjunctival bleb in an effort to lower IOP.
• In 1961, Sugar suggested a microsurgical technique
called trabeculectomy with guarded fistula, which was
published by Cairns in 1968
• TRABECULECTOMY+ANTIMETABOLITES=GOLD
STANDARD FOR SURGICAL MANAGEMENT OF
GLAUCOMA

4. MECHANISM
• Allows aqueous outflow from
the anterior chamber to the
sub-Tenon space, through the
fistula & scleral flap borders
and finally collected into
episcleral & conjunctival vei ns
• A functioning filtering bleb
forms over the sclerostomy
site which appears as a blister-
like elevation of the
conjunctiva.

5. INDICATIONS
• ABSOLUTE INDICATIONS
• Failure of conservative therapy to achieve good IOP control
• Avoidance of excessive polypharmacy
• Progressive deterioration despite seemingly adequate IOP control
• Poor compliance to medical treatment
• Primary therapy – in advanced disease requiring a very low target
pressure, particulalry in younger patients
• Patient preference – they want to be free of comitment to chronic
medical treatment
• RELATIVE INDICATIONS
• Economic considerations: In developing countries like India
• Ocular or systemic side effects of antiglaucoma medications.

6. RELATIVE CONTRA-INDICATIONS
• Blind eye
• Active inflammation
• Active anterior segment neovascularization
• Extensive conjunctival scarring / thin sclera(prior surgery,
chemical trauma)

7. PRE-OP EVALUATION
• Thorough ophthalmic evaluation including IOP, visual
fields and ONH evaluation
• Complete systemic evaluation with respect to diabetes,
hypertension, cardiovascular diseases – stop
anticoagulants & antiplatelet agents
• Medications which affect the ocular surface and disrupt
the blood aqueous barrier should be stopped 1 to 2
weeks prior to surgery
• Prophylactic peripheral iridotomy in angle closure
disease.
• Conjunctival mobility should be checked pre operatively
to plan the site of surgery.

8. • Topical pilocarpine may be used preoperatively to constrict
the pupil
• Preoperative topical sympathetic agonists (e.g. apraclonidine
1%, adrenaline 0.01% or 0.1%) cause anterior segment
vasoconstriction and hence reduce intraoperative bleeding
• Povidone-iodine has a broad spectrum of antimicrobial action
and is used to prepare the periorbital skin, the eyelids and the
ocular surface
• In uveitic glaucoma, the use of preoperative topical and/or
systemic steroids may be required to ensure optimal control of
ocular inflammation prior to surgery

9. ANESTHESIA
• PERI/RETROBULBAR – don’t inject more than 5ml
• A facial block can be given to weaken the orbicularis
oculi.
• Topical anesthesia with intracameral anesthesia avoids
conjunctival damage, chemosis, SCH but no akinesia
achieved
• Subconjunctival anesthesia is less preferred
• General anaesthesia - in pediatric age group, highly
anxious patients or with suboptimal mental status. Allows
maximal control over systemic blood pressure and also
IOP intraoperatively.

10. PROCEDURE
• Eye painted & draped
• Eye exposed with lid speculum
• TRACTION SUTURE - To keep eye in inferior position
1. Clear corneal suture
• Better exposure, less complications
• 7-0 spatulated vicryl/silk at half thickness, 2mm anterior to limbus
2. SR bridle suture
• Associated with many complications

11. CONJUNCTIVAL FLAP
• Surgical site – in upper part of globe under upper eye lid. Either ST
or SN quadrant chosen to preserva superior quadrant for future
repeat of surgery
LIMBAL BASE FORNIX BASE
Atleast 8mm from limbus 2mm wide, 6-8mm length
Difficult, takes longer Easier, faster
Not as good exposure Good exposure
Limited area for antifibrotic treatment Larger area for antifibrotic treatment
Bleb – cystic with RING OF STEEL with
anterior drainage
Diffuse bleb with posterior drainage
Difficult for re-operation Can be combined with phaco-trab
Lesser incidence of conjunctival wound
leakge
Higher incidence of conjunctival wound
leakge

12. • Tenon’s can be separated either separately or with
conjunctiva
• Bleeding episcleral vessles should be gently
diathermized
• Green Dots - restricted
posterior aqueous flow
with a ring of scar
tissue - RING OF
STEEL
• Anteriorly directed
aqueous flow (arrows)

13. ANTIMETABOLITES
MITOMYCIN-C 5-FLUOROURACIL
An alkaloid, synthesized by
Streptomyces caespitosus
A pyrimidine analogue
Affects fibroblast proliferation by
cross-linking DNA
Blocks DNA synthesis by inhibiting
thymidylate synthesis
0.2 to 0.5 mg/ml upto 5 mins 50mg/ml for 5 mins
Soaked sponges are placed
beneath the conjucntival flap
Intra-op: sponges soaked
Post-op: 0.1ml (5mg) subconjunctival
injection daily for 7-14 days

14. • Polyvinyl alcohol sponges soaked in antifibrotic agent
• Conjunctival egdes kept away with T clamps
• After usage soaked pieces are removed & discarded
• Eye irrigated with 20-60ml BSS and fluid discarded in
toxic waste container
• Larger area of antifibrotic treatment- diffuse non cystic
blebs

16. POTENTIAL COMPLICATIONS OF ANTI-
METABOLITIES
• Increased duration & concentraion – thin avascular
cystic blebs, hypotony
• Epithelial erosions – mainly 5-FU
• Intraocular penetration & damage  endothelial
damage, ciliary body destruction
• Infections  blebitis, endophthalmitis and leakage.
• Scleritis, scleomalacia, necrosis

17. SCLERAL
FLAP
RECTANGULAR TRIANGULAR
Initial horizontal incision 4mm behind
limbus, followed by lamellar
dissection anteriorly just into clear
cornea
Isosceles triangle with base 1mm
behind limbus, apex towards fornix
3.5 × 4.5 mm 3mm base, 3-4mm each side
Recommended to leave 1mm border
between flap & limbus
• To provide resistance to aqueous outflow & prevent hypotony.
• Rectangular, triangular, trapezoids
• 1/3 to 1/2 scleral thickness

18. PARACENTESIS
• Done to enable the surgeon
to maintain the AC
• Infusion for continuous IOP
maintainence by AC
maintainer
• To test for patency of
filtration site by injecing fluid
into AC
• To prevent intra-op flat AC

19. SCLEROSTOMY
• Fistula created by hand cut or KELLY DESCEMETS
PUNCH
• Internal block excision – The block is first outlined with
a blade,followed by entry into the A/C through the
anterior edge. The rest of the block is dissected
posteriorly to full-depth, using a blade or scissors to cut
the base.
• Sclerostomy punch – preferred. An anterior
corneoscleral incision is made. The punch is then
inserted to engage the full-thickness of the limbus. It
should be aligned perpendicular to the eye to ensure a
clean and nonshelved sclerostomy

20. • Anterior corneoscleral entry into AC- reduces risk of iris
incarceration and bleeding from iris root and ciliary body
• Posterior extension – damage to ciliary body with
hemorrhage & ostium blockage by uveal tissue.
• 0.5–1.0 mm – adequate ostium size

21. PERIPHRAL IRIDECTOMY
• To prevent iris incarceration &
ostium blockage
• performed through the
sclerostomy using Vannas
scissors
• Base of the iridectomy should be
little wider than sclerostomy
opening
• Complications:
Hyphaema, inflammation, iridodialysis

22. SCLERAL FLAP CLOSURE
• Flap construction
• Suture position determines control of
• Tension resistance to outflow
• 10-0 Nylon suture
• Suture knots to be buried
• Types of sutures
• Fixed, interrupted sutures
• Adjustable sutures
• Releasable sutures

23. FIXED INTERRUPTED SUTURES
• Usually put at the upper corners of
the rectangular flap
• LASER SUTURE LYSIS
• Introduced by Lieberman (1983)
using argon laser
• Promotes aqueous flow through
sclerostomy around the edges of
flap

24. ADJUSTABLE SUTURES
• Allows a trans-conjunctival adjustment of pressure
post-operatively
• Using a specially designed forceps with blunt tip
• Khaw adjustable suture forceps

25. RELEASABLE SUTURES
• First originated from Shaffer et al (1971)
• An exterior loop burried in stroma present which can be
pulled at slit lamp
• Many techniques – Wilson’s, Shins’s, Cohen’s, Kolker’s,
Johnstone’s

26. CONJUNCTIVAL CLOSURE
• Closure must be water-tight
• 10-0 nylon or 10-0/9-0 vicryl can be
used
• Single interrupted sutures
• Edge purse-string sutures
• Interrupted horizontal mattress
• Creation of corneal grooves for
conjunctival closure of fornix-based
flap to minimize wound leakage and
suture discomfort

27. • Anterior chamber is reformed with BSS through the
paracentesis
• Test leakage with Seidel technique
• At the end of surgrey, cycloplegics/mydriatics can be
used
• ATROPINE 1%
• Relaxation of ciliary muscle & pain relief
• Prevention of central posterior synechae
• Less AC shallowing
• Dilated pupil – lens cornea touch if AC shallows

28. POST-OP MANAGEMENT
• Follow-up closely – Success = 50% surgery + 50% post-
op care
• Topical steroids: suppression of wound healing
• Prednisolone acetate (1%) 2 hourly for 2 weeks and tapered over
8 weeks
• Topical antibiotics: 4 weeks post operatively
• Topical mydriatic/cycloplegic agent : Atropine 1%
prevents AC shallowing and risk of malignant glaucoma
• Oral or IV steroids: not routinely used , in severe uveitic
glaucoma

29. • Adjuvant subconjunctival 5-FU
• After first postoperative week for up to several months to
modulate wound healing
• 5mg (0.1 ml of 50mg/ml) 5-FU deep in superior fornix
• Indications
• As a part of planned postop regimen in cases high risk of failure
• Signs of imminent bleb failure
• Adjuvant therapy after needling or re-exploration
• After several months for persistent healing response & rising IOP

30. POST-OP ASSESSMENT
• First 10 days are crucial to
ascertain adequacy & extent of
filtration
1. BLEB
GOOD BLEB UNFAVOURABLE BLEB
Vascularity similar to surrounding
conjunctiva
Increased vascularisation
Numerous microcysts Loss of microcysts
Diffuse bleb Encapsulated bleb
Moderate eleveation Cork screw vessels
Raised IOP
Increased wall thickness

31. MIGDAL & HITCHINGS
BLEB CLASSIFICATION
• TYPE 1 BLEB (very low IOP, elevated
bleb)
• Thin, transconjunctival flow of aqueous
• Good filtration
• TYPE 2 BLEB (low IOP, elevated bleb)
• IDEAL BLEB
• Thin, diffuse, relatively avascular
• Microcysts, good filtration
• TYPE 3 BLEB (high IOP, low localized
bleb)
• Flat, no microcysts
• Engorged vessels, non filtering
• TYPE 4 BLEB (high IOP, encapsulated
• Localised, high elevated, engorged vessels
• Cyst like cavity of hypertrophied Tenon’s

32. MOORFIELDS BLEB GRADING SYSTEM

33. INDIANA BLEB GRADING SYSTEM

34. 2. ANTERIOR CHAMBER
• Look for hyphema, hypopyon
• Assess depth
• Shallow post-op AC
• Grade 1 : Peripheral corneal iris touch
• Grade 2 : Corneal iris touch upto pupillary margin
• Grade 3 : Lens cornea apposition
3. CORNEA : look for epithelial erosion, edema
4. IOP
5. FUNDUS : choroidal detachment, suprachoroidal
hemorrhage, decompression retinopathy

35. DIGITAL OCULAR
MASSAGE
• Lowers IOP
• Breaks early adhesions & forces aqueous flow through
sclerostomy
• Establishes increased flow rate via large bleb
• Techniques :
• Firmly press through lower lid against cornea for 5-10 sec
• Push with 2 fingers on either side of bleb with eye in down gaze
• Apply pressure on conjunctiva over radial edge of sclleral flap
with moistened cotton-tipped applicator
• Complications – hyphema, bleb rupture, iris inarceration,
dehiscence of incisional wound

36. ARGON LASER
SUTURE LYSIS
• Facilitated by compressing conjunctiva to visualize
scleral suture or high magnification suture lysis contact
lens (Hoskins or Blumenthal lens)
• Argon laser: 50-100μm, 0.05-0.1 sec duration, 200-400
mW power
• Within first 2 weeks: enhance filtration before scarring
occurs
• Delayed (upto 6 weeks) if
intraoperative antimetabolite used

37. BLEB NEEDLING REVISION
• Aim - to increase the size of the sub-Tenon’s aqueous
lake whilst avoiding overdrainage and hypotony
• Puncturing & loosening the scar tissue of filtration bleb to
increase sub-tenon’s aqueous lake
• Two types - Sub-Tenon’s Needling, Subscleral flap
Needling

38. SUB-TENON’S NEEDLING REVISION
• Approached with a 29.5 gauge needle via a very posterior
superior fornix entry
• Multiple stabs toward the scleral flap are made until a
clear increase in bleb size is achieved
• Gentle circumferential sweeps may be used only on
exiting
• Moorfields controlled needling procedure - if there is
inadequate flow a larger gauge needle is used up to
microvitreoretinal (MVR) blade
• Subscleral Flap Needling Revision - if sub-Tenon’s
needling fails. It is a high-risk procedure and direct
visualization of the needle tip may not be possible

39. COMPLICATIONS
INTRA-OP
• Conjunctival flap related
• Scleral flap related
• Shallow AC
• Hyphema
• Suprachoroidal hemorrhage
• PI related
• Vitreous loss & lens injury
POST-OP
• WIPE-OUT phenomenon
• Shallow AC with low IOP
• Shallow AC with high IOP
• Normal AC depth with high IOP
• Bleb leak
• Overfiltration
• Ciliochoroidal detachment
• Malignant glaucoma
• Retinal complications
• Filtration failure
• Encapsulated bleb
• Cataract
• Bleb related endophthalmitis

40. CONJUNCTIVAL FLAP RELATED
• Tears and button holes
• Shrinkage
• Treatment
• Large button hole during early stage - select new site
• In centre of flap - purse string suture
• Near limbus - Oversewn with adjacent conjunctiva or
sutured directly to cornea
• Tenon’s capsule should be incorporated to increase
strength

41. SCLERAL FLAP RELATED
TOO THIN
• Tearing, button holing,
avulsion
• Rx – buttonholing
plugged with Tenon’s,
donor sclera
TOO THICK
• Underfiltration
• Premature AC entry
• Rx – Superficial scleral
lamellae must be
dissected
• Large tears – change site
• Small tears – repaired with 10-0 nylon
• Flap shrinkage – additional sutures to reduce excess outflow

42. • SHALLOW AC
• Viscoelastic injection
• Preplaced scleral flap sutures
• HYPHEMA
• During PI, conjunctival dissection, episcleral &
perforating vessels, sclerostomy site
• Stop antiplatelet, anticoagulants
• Gentle handing, adequate cautery
• Punch till blue-white junction & not beyond it
• Rx
• Light compression
• Keep scleral flap open to allow blood to exit along with
gentle irrigation
• Persistent bleed – visco/air tamponade

43. SUPRACHOROIDAL HEMORRHAGE
• Can occur at any time intra-op & post-op
• Delayed – prolonged hypotony, ciliochoroidal effusion
• Precautions
• Avoid prolonged hypotony
• Preplaced flap sutures
• Tighter flap closure & postop suture lysis
• Controlled decompression of globe
• Use of punch instead of block excision
• Signs – shallowing of AC, dark expansion of choroid
• Rx – wound closure immediately – IV Mannitol
• Posterior sclerotomies – to drain hemorrahage

44. • PI related
• Large PI
• Iridodialysis
• Vitreous loss & lens injury
• Zonular-lens complex damaged during PI
• Sudden decompression of globe with forward shift of iris-
lens diaphragm
• Avoid posterior sclerostomy, basal PI
• Rx
• Anterior vitrectomy to be done to avoid ostium blockage

45. WIPE-OUT PHENOMENON
• 1-2% risk in all glaucoma surgeries
• Early undetected visual field loss/central fixation loss
• Typically occurs in advanced glaucoma with split fixation
or VF loss within 5 degrees of fixation
• Precautions
• Sub Tenon’s anesthesia
• Avoid Adrenaline use
• Avoid post-op IOP spike
• Prompt management of post-op IOP spike

46. SHALLOW AC WITH
LOW IOP
• Causes
• Overfiltration
• Choroidal detachment with decreased aqueous production
• Wound leak
• Treatment
• Grade 1 – reforms spontaneously
• Grade 2 – observation
Reform AC with visco/air
• Grade 3 – immediate correction
choroidal drainage

47. SHALLOW AC
WITH HIGH IOP
PUILLARY BLOCK SUPRACHOROIDAL
HEMORRHAGE
AQUEOUS
MISDIRECTION
PI not patent Diffuse shallow AC Annular CD with anterior
rotation of CB
Iris bombe Siedels’s negative Posterior pooling of
aqueous
Siedels’s negative Dark choroidal elevation Flat AC
Normal fundus
Normal fundus Rx Siedels’s negative
Rx Observation Rx
Medically reduce IOP If large - drainage Mydriatics/cyclolegics
Laser PI Aqueous suppressants
Mydriatics with topical
steroids
Nd YAG hyaloidotomy
Vitreous tap, PPV

48. DEEP AC WITH HIGH IOP
• Causes
• Obstruction of ostium
• Tight flap sutures
• Failing bleb
• Steroid induced IOP response
• Bleb is flat/low
• Rx
• Gonioscopy- to look for patency of ostium
• Nd YAG laser- to disrupt fibrin, vitreous, iris
• Ocular massage/suture release
• Failing bleb-increase topical streoids, ocuar massage, postop
augmentation with antimetabolites, needling of bleb

49. EARLY BLEB LEAK
• Causes
• Button hole of conjunctiva
• Inadvertently sutured conjunctival incision
• Antimetabolite augmented trabeculectomy
• CF
Shallow/flat AC choroidal detachment
IOP<6mmHg chances of endophthalmitis
Siedel’s positive Va reduced
Striate keratopathy
• Precautions
• Careful conjunctival dissection
• Avoid toothed foreceps
• Meticulous flap closure
• Avoid antimetabolite contact with conjunctival edges
• Copious irrigation

50. RX
CONSERVATIVE
• Sytemic & topical
aqueous suppressants –
proliferation of surface
epithelium
• Pressure patch, BCL,
scleral shell collagen
sheild
SURGICAL
• If no improvement for
conservative treatment in
2 days
• Suturing of leak site
• Surgical bleb revision
• Cyanoacrylate glue

51. LATE BLEB LEAK
• Causes
• Disintegation of conjuntiva overlying sclerostomy
• Necrosis of surface epithelium
• Rx

52. CILIOCHOROIDAL DETACHMENT
• Commonly after full thickness surgery
• Rx
• Resolves with topical & systemic steroids
• Prophylactic sclerotomy in predisposed eyes
• Surgical drainage in case of cornea lens touch

53. OVERFILTRATION
• CF
• Hypotony (IOP<6mmHg)
• Shallw AC
• Large, diffuse bleb
• No wound leak
• Rx
• Patching with focal compression over region of excessive
aqueous flow
• Symblepharon ring, Simmon’s tamponade shell
• Reform AC
• Autologous blood injection into bleb
• Cryo or laser application to reduce bleb size
• Compression sutures
• Surgical revision

55. • DECOMPRESSION RETINOPATHY
• Sudden decompression of eye in high IOP – transient
increase in retinal & chroidal blood flow
• Retinal, subretinal, suprachoroidal hemorrahage
• Mimics CRVO
• HYPOTONIC MACULOPATHY
• In chronic hypotony
• Choroidal folds in macular area
• Maclar thickening
• Disc swelling

56. FILTRATION FAILURE
• Due to wound healing process – 2 weeks
• Recognition is important
• Meticulous examination
EXTRASCLERAL SCLERAL INTROCULAR
Subconjunctival
fibrosis
Overtight flap sutures Obstruction of fistula
Episcleral fibrosis Scarring of scleral bed
Bleb encapsulation
Racial & genetic
factors

57. Classification
High IOP Low bleb
High bleb
Low IOP
Low bleb
High bleb
• Closure of ostium
• Subconjunctival
fibrosis
• Encapsulated bleb
• Bleb leaks
• Overfiltration
• Antimetabolite realted

58. RX
OBSTRUCTION
• Low energy argon laser
• Internal bleb revision
• Bleb needling
FAILING BLEB
• Increase steroid dosage
• Digital pressure
• Suturolysis
• Fibrin clot – intracameral
tPAs
• Restart AGMs
• Needling of encysted bleb
• Subconjuntival 5FU
• Drainage implants

59. FAILING &
FAILED BLEBS
• Blebs associated wit inadequate IOP control,
impending/established obstruction of aqueous outflow
EARLY FAILED BLEB LATE FAILED BLEB
<1 month >1 month
High IOP Initial good IOP control with good
bleb
Low hyperemic bleb Due to subconjunctival & episcleral
fibrosis
Due to ostium obstruction, tight
sutures, incomplete excision of DM
In young patients, blacks, postop
SCH, inflammation

60. MANAGEMENT
EARLY FAILED BLEB
• Increase topical steroids
• Treat blockage
• Digital massage with
compression
• Suturolysis
• Release sutures
• tPAs
• Bleb revision
LATE FAILED BLEB
• Restart medical
management
• Nd YAG laser/bleb
needling
• Laser internal revision
• If falied – repeat
trabeculectomy or
drainage device

61. ENCAPSULATED BLEB
• Tenon’s cyst – 10-28%
• A localized, highly elevated, dome shaped, cyst like
cavity of hypertrophied tenon’s capsule with engorged
blood vessels
• During first 8 weeks
• Risk factors – young, male, glove powder, prolonged
AGM use, prior ALT/conjunctival surgery
• Inflammatory mediators + collagen producing fibroblasts
= Fibroblast proliferation
• High IOP after initial period of IOP control

62. MANAGEMENT
MEDICAL
• Spontaneous resolution
within 2-4 weeks
• Topical aqueous
suppressants
• Steroids
• Digital massage
SURGICAL
• Bleb needling with 5FU
• Excision of fibrous tissue
with 5FU

63. BLEBITIS
• White bleb with surrounding intense conjunctival injection
• Variable anterior chamber reaction
• Clear vitreous
• Risk factors:
• Early chronic intermittent bleb leak
• Myopia: thin scleral flap
• Intra-operative MMC
• Blepharitis
• Diabetes mellitus
• Chronic antibiotic use
• Inv : conjunctival swab
• Treatment: Topical antibiotics

64. BLEB-RELATED
ENDOPTHALMITIS
• Early postoperative Endophthalmitis
• Onset within first 3 months
• Staphylococcus epidermidis
• Delayed- onset Endophthalmitis
• Onset after 3 months
• Streptococcus, staphylococcus, H. influenzae
• Incidence – 0.2-9.6%
• Pain, photophobia, sticky eyes, reduced vision
• Milky white appearance of bleb, fibrin or hypopyon in AC & vitritis
(distinguishes from blebitis
• Inv
• Aqueous and vitreous aspirates
• Gram stain, Giemsa stain
• Rx
• High dose parenteral and periocular antibiotics
• Intravitreal antibiotics

65. SYMPTOMATIC BLEB
• BLEB DYSESTHESIA
• Usually are asymptomatic or reasonably well tolerated
• Most patients are aware of a conjunctival “blister”;
• Symptoms are frequent in nasal or large blebs or when there is
extension into cornea
• SPKs, difficulty with blinking, tear film abnormalities with
secondary Dellen formation, foreign-body sensation, & induced
astigmatism
• Rx
• Artificial tears
• Surgical bleb excision or conjunctival flap reinforcement
• Bleb shrinkage : cryotherapy, Nd:YAG laser thermotherapy,
argon laser, diathermy, and cauterization

66. COLLAGEN
IMPLANTS
• Increases efficacy without need for antimetabolites
• Made of PORCINE – atelocollagen cross-linked with GAGs
• Biodegraded around 90-180 days
• 2 sizes – 6x2, 12x1
• Mechanism
• Provides a scaffolding for fibroblasts to grow randomly which could
reduce scar formation effectively
• Collagen matrix itself can function like a reservoir to absorb aqueous
• Provides pressure on scleral flap to create controlled drainage in
subconjunctival space
• Not inhibitors or antifibrotic agents

67. • Indications
Trabeculectomy Strabismus, oculoplastic sugery
Deep sclerectomy Pterygium excision,
Bleb revision Subconjunctival scar revision
• Technique
• After scleral sutures, collagen matrix is placed over flap
• No suture required
• As soon as it touches the sclera, it absorbs aqueous & moulds to
scleral tissue
• Limits hypotony by tamponading effect
• Modulates wound healing
• Less surgical time, no special handling of tissue
• Laser suture lysis is difficult

68. • EXPRESS™ MINI SHUNT - a non
valved stainless steel device about 3 mm
long & has a flat, angled faceplate that is
designed to rest flush with the sclera
under the scleral flap. The distal end of
the shunt rests in the anterior chamber
• Placement under a partial-thickness
scleral flap
• Similar efficacy as traditional
trabeculectomy.
• Lower incidence of postop hypotony and
choroidal effusions

69. COMBINED CATARACT AND GLAUCOMA
SURGERY
• INDICATIONS - visually significant cataract
• with more than 3 medications for IOP control
• intolerant or allergic to glaucoma medications
• significant cupping or visual field loss as the optic nerve is less
able to tolerate perioperative IOP rise
• monocular patient
• XFS, pigment dispersion syndrome & angle recession.
• DEFERRAL
• Active uveitis, neovascular glaucoma and acute angle closure
glaucoma.

70. • TECHNIQUES
• One site approach
• Two site approach
• Combined surgery has the advantage of treating both
diseases with a single surgical intervention and IOP
reduction tends to be greater than with cataract surgery
alone.
• Disadvantages include increased surgery time which can
increase surgical risk

71. REPEAT
TRABECULECTOMY
Target IOP not achieved, VF
deteriorates
Add topical AGMs
Needling, excision of encapsulated tissue
Revision of original Trab
Re-do Trab at another site
Deep sclerectomy with MMC
cyclodiode

72. • Choice of treatment following a failed Trabeculectomy is
individualized for each patient where factors like age,
ocular anatomy, detalis of primary procedure, condition
of other eye may guide the decision
• Technique of repeat trabeculectomy
• Site – superonasal, superotemporal
• Conjunctical incision – difficult, hydrodissect conjunctiva
through subconjunctival BSS
• Antimetabolites – mandatory, 0.4mg/ml MMC for 3 mins
• Scleral flap – mini trabeculactomy
• Post-op – topical preservative free steroids
• Outcome – less succesful than initial trabeculectomy

73. DRAINAGE DEVICES
• to shunt aqueous from the AC into a subconjunctival reservoir
• NONVALVED
1. MOLTENO IMPLANT - silicone tube that connects to the
upper surface of a thin acrylic plate which acts as a
collecting reservoir
2. BAERVELDT’S IMPLANTS - a silicone tube which was
attached to a silicone plate impregnated with barium
3. SCHOCKET TUBE SHUNT - shunts aqueous from
ACthrough a tube to the equatorial
subtenon’s Collecting reservoir.

74. • VALVED
1. KRUPIN-DENVER VALVE – open
supramid tube connected to a silastic tube
with a slit valve with an opening pressure
of 11-14 mm Hg and a closing pressure of
1-3 mm Hg lower
2. AHMED GLAUCOMA VALVE – pear
shaped end-plate made of poly propylene
or silicone with fenestrations
3. WHITE PUMP SHUNT - silicone tub
connected to a 16 to 18 ml balloon that
has an outlet tube into the retrobulbar
space
4. JOSEPH VALVE - one-piece device
consisting of a curved tube with a slit valve
connected to a silicone rubber strap

75. • Glaukos iStent - a titanium device placed inside the
Schlemm’s canal allows the aqueous humor to flow
directly into the canal, bypassing the trabecular
meshwork.
• The Gold Microshunt - a biocompatible gold shunt
implanted in the suprachoroidal space uses the eye’s
natural pressure differential to divert the aqueous into
the suprachoroidal space in a controlled fashion.

76. REFERENCES
• Diagnosis and therapy of glaucoma – Becker-Shaffer, 8th
edition.
• ISGS textbook of glaucoma surgery – Shaarawy
• Glaucoma – AAO
• Aravind – Diagnosis and management of Glaucoma
• The Gkaucoma Book - Paul N. Schacknow, John R.
Samples