About trabeculectomy

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

56. THANK YOU