Trabeculectomy is a surgical procedure to lower intraocular pressure by creating a fistula between the anterior chamber and subconjunctival space. This allows aqueous humor to drain out of the eye and form a filtering bleb under the conjunctiva. It involves making a partial thickness scleral flap, creating a sclerostomy, and sometimes using antimetabolites to modulate healing. The procedure aims to lower IOP while avoiding complications like hypotony, infection, or bleb failure. Close postoperative monitoring is required to manage IOP and bleb formation.

1. Trabeculectomy

2. 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 lOP.
• TRABECULECTOMY+ANTIMETABOLITES = GOLD STANDARD
FOR SURGICAL MANAGEMENT OF GLAUCOMA

3. Mechanism
• Allows aqueous outflow from the anterior chamber to the
sub-tenon space, through the fistula & scleral flap borders
and finally collected in to episcleral & conjunctival veins
• A functioning flitering bleb forms over the sclerostomy site
which appears as a blister like elevation of the conjunctiva.

4. Indications
• ABSOLUTE INDICATIONS.
• Failure of conservative therapy
• Deterioration despite seemingly adequate lOP control
• Poor compliance
• Primary therapy — in advanced disease requiring a very low
target pressure, particularly in younger patients
• Patient preference
• RELATIVE INDICATIONS
• Economic considerations: In developing countries like India.
• Ocular or systemic side effects of antiglaucoma medications.

5. Relative Contraindications
• Blind eye
• Active inflammation
• Active anterior segment neovascularization
• Extensive conjunctival scarring /thin sclera(prior surgery ,
chemical trauma

6. Pre Op Evaluation
• Thorough ophthalmic evaluation including lOP, visual fields and
ONH evaluation
• Complete systemic evaluation with respect to diabetes,
hypertension, cardiovascular diseases
• Stop anticoagulants & antiplatelet agents
• Prophylactic peripheral iridotomy in angle closure disease.
• Conjunctival mobility should be checked pre operatively to plan
the site of surgery.

7. • Topical pilocarpine may be used preoperatively to constrict
the pupil
• Preoperative topical sympathetic agonists (e.g.
apraclonidine, adrenaline 0.01% or 0.1%) cause anterior
segment vasoconstriction and hence reduce intraoperative
bleeding
• Povidone-iodine 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

8. Anaesthesia
• PERI/RETROBULBAR — don’t inject more than 5ml
• Topical anesthesia with intracameral anesthesia avoids
conjunctival damage, chemosis, SCH
• 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 lOP
intraoperatively.

9. • 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
• 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 preserve superior
quadrant for future repeat of surgery

12. ‘ Green Dots – restricted posterior aqueous
flow with a ring of scar tissue - RING OF STEEL•
Anteriorly directed aqueous flow (arrows)

13. Antimetabolites

14. • Polyvinyl alcohol sponges soaked in antifibrotic agent.
• Conjunctival edges kept away with T clamps. After usage
soaked pieces are removed & discarded, eye irrigated with 20-
6Oml BSS Larger area of antifibrotic treatment- diffuse non
cystic blebs

15. Complications
• Increased duration & concentraion — thin avascular cystic
blebs, hypotony
• Epithelial erosions — mainly 5-FU
• Intraocular penetration & damage – endothelial damage,
ciliary body destruction
• Infections - blebitis, endophthalmities and leakage.
• Scleritis, scleromalacia, necrosis

16. Scleral Flap
• To provide resistance to aqueous outflow & prevent
hypotony.
• Rectangular, triangular, trapezoids

17. Paracentesis
• Done to enable the surgeon to maintain the AC
• Infusion for continuous lOP maintenance by AC maintainer-
• To test for patency of filtration site by injecting fluid into AC.
• To prevent intra-op flat AC

18. Sclerostomy
• Fistula created by hand cut or KELLY DESCEMETS PUNCH
• Internal block excision
• 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

19. • 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

20. Peripheral 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

21. 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
Scleral flap closure

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

23. • Anterior chamber is reformed with BSS through the
paracentesis
• Test leakage with Seidel technique
• At the end of surgery, cycloplegics/mydriatics can be used
• ATROPINE 1%
• Relaxation of ciliary muscle & pain relief Prevention of central
posterior synechae
• Less AC shallowing

24. Post Op management
• Follow-up closely
• Prednisolone acetate (1%) 2 hourly for 2 weeks and tapered
over 8 weeks
• Topical antibiotics: 4 weeks post operatively
• Topical mydriatic/cycloplegic agent : Atropine I % prevents AC
shallowing and risk of malignant glaucoma
• Oral or IV steroids: not routinely used , in severe uveitic
glaucoma

25. • Adjuvant subconjunctival 5-FU after first postoperative week
for up to several months to modulate wound healing• 5mg
(0.1 ml of 5Omgfml) 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
lop

26. Post op Assessment
• First 10 days are crucial
• Bleb

27. Migdel and Hitchings Classification
• TYPE I BLEB (very low lOP, elevated bleb) Thin,
transconjunctival flow of aqueous good filtration
• TYPE 2 BLEB (low lOP, elevated bleb) IDEAL BLEB
thin, diffuse, relatively avascular microcysts, good
filtration
• TYPE 3 BLEB (high lOP, low localized bleb) flat, no
microcystes engorged vessels, non filtering
• TYPE 4 BLEB (high lOP, encapsulated localised,
high elevated, engorged vessels. Cyst like cavity of
hypertrophied Tenon’s

28. • ANTERIOR CHAMBER
• Hyphema, hypopyon
• Shallow post-op AC
• Grade 1 : Peripheral corneal iris touch
• Grade 2: Corneal iris touch upto pupillary margin‘
• Grade 3: Lens cornea apposition
• CORNEA: look for epithelial erosion, edema 4.
• Iop
• FUNDUS : choroidal detachment, suprachoroidal hemorrhage,
decompression retinopathy

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

30. Bleb needling
• Aim - to increase the size of the sub-Tenons aqueous lake
while 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

31. Complications

32. 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

33. Scleral flap Related

34. • SHALLOW AC
• Viscoelastic injection
• Preplaced scleral flap sutures
• HYPHEMA
• During Pl, 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 scIeraI flap open to allow blood to exit along with gentle
irrigation
• Persistent bleed — visco/air tamponade

35. Suprachoroidal hemorrhage
• Can occur at any time intra-op & post-op
• Delayed
• 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

36. • Pl related
• Large Pl iridodialysis
• Vitreous loss & lens injury
• Zonular-lens complex damaged during Pl
• Sudden decompression of globe with forward shift of iris-lens
diaphragm
• Rx‘ Anterior vitrectomy to be done to avoid ostium blockage

37. 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 Tenons anesthesia
• Avoid Adrenaline use
• Avoid post-op lOP spike
• Prompt management of post-op lOP spike

38. 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

39. Shallow AC with high IOP

40. Deep AC with high IOP
• Causes
• Obstruction of ostium
• Tight flap sutures
• Failing bleb
• Steroid induced lOP 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,.
• Post op augmentation with antimetabolites,
• Needling of bleb

41. 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

42. Overfiltration
• CF.
• Hypotony (IOP<6mmHg)
• Shallow 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

43. Decompression Retinopathy
• DECOMPRESSION RETINOPATHY‘ Sudden decompression of
eye in high lOP — transient increase in retinal & chroidal
blood flow‘ Retinal, subretinal, suprachoroidal hemorrahage
‘Mimics CRVO‘HYPOTONIC MACULOPATHY‘ In chronic
hypotony Choroidal folds in macular area Macular thickening
Disc swelling

44. Filtration Failure

45. Management

46. 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 lOP after initial period of lOP control

47. Management

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

49. Bleb related Endophthalmities
• Early postoperative Endophthalmitis
• Onset within first 3 months
• Staphylococcus epidermicis
• Delayed- onset Endophthalmitis Onset after 3 months
Streptococcus, staphylococcus, H. influenzae
• Pain, photophobia, sticky eyes, reduced vision Milky white
appearance of bleb, fibrin or hypopyon in AC &
vitritis(distinguishes from blebitis Aqueous and vitreous
aspirates
• High dose parenteral and periocular antibiotics.
• Intravitreal antibiotics

50. Symptomatic bleb
• BLEB DYSESTHESIA
• 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, difficulty with blinking, tear film
abnormalities, 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

51. Collagen implants
• Increases efficacy without need for antimetabolites
• Made of PORCINE — a telocollagen cross-linked with GAGs
• Biodegraded around 90-1 80 days 2sizes—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 scIeral flap to create
controlled drainage in subconjunctival space

53. Combined Surgery
• INDICATIONS - visually significant cataract
• with more than 3 medications for lOP control
• intolerant or allergic to glaucoma medications significant
cupping or visual field loss as the optic nerve is less able to
tolerate perioperative lop rise.
• monocular patient.
• PFS, pigment dispersion syndrome & angle recession.

54. • Combined surgery has the advantage of treating both
diseases with a single surgical intervention and lOPreduction
tends to be greater than with cataract surgery alone.-
Disadvantages include increased surgery time which can
increase surgical risk

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

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