**5. Complications of trabeculectomy**

before, during and after surgery. Physicians managing such conditions are involved in the overall care of the patient. Those with high or minimally responding IOP may benefit from systemic carbonic anhydrase inhibitors or osmotic agents to further reduce the pressure before the procedure is performed. Trabeculectomy can be done as an outpatient procedure in selected cases, but, in most instances, due to the nature of the environment (long distance from eye care facility; hostile, dirty and unhygienic situation of the living environment; and illiteracy), patients often require inpatient care and are discharged within a week. POAG surgery is usually performed under local anaesthesia using lignocaine-containing adrenaline in appropriate dilution. General anaesthesia is administered where there is a need to do so.

This is performed in the operating theatre under complete aseptic condition. The surgeon and assistant are fully scrubbed and gowned. The skin around the eye is cleaned with povidone iodine 5% which is also used to wet and subsequently flush the conjunctiva with normal saline; adhesive drapes are placed leaving the globe area exposed. A wire speculum is used to part the lids, the superior rectus muscle is picked with toothed forceps and 4/0 silk suture is passed under it. A conjuctival flap is then raised. This can either be fornix or limbal based. Limbalbased flap reduces risk of fibrosis over the filtration drainage site though some believe it allows a freer connection of the surgical site with external conjuctiva and may in theory increase infection risk. Proponents of fornix flap believe it offers greater wound closure and lower infection risk. A caliper is used to demarcate proposed area to raise the outer sclera flap of 5 by 5 mm size. The area is cleared of tenons and haemostasis secured with bipolar wet field cautery. Ideally a separate trolley is used for administration of antimetabolite. A 5% dilution of mytomycin C or 5- fluorouracil is employed. A piece of cotton wool is soaked with the agent and applied over the sclera flap site for five minutes and then washed with 50 millilitres of normal saline. The trolley is subsequently taken away and the surgeons change gloves. The outline of the outer sclera flap is demarcated gently with a scalpel. The proximal part is gently elevated to form the lip of the partial thickness scleral flap. A chooks knife is then used to bluntly dissect the flap from the base of the cornea. A smaller inner sclera flap of 3 by 3 mm is then raised and excised. This is followed by a peripheral iridectomy. The outer flap is sutured at the two proximal edges. Some clinicians prefer to suture all the 4 edges with 10/0 silk sutures. The knots are buried in the sclera. The anterior chamber (A/C) is reformed with saline via a cannula. Conjunctiva is sutured at the edges in fornix-based flap. A running suture with a knot at the two ends can be used to close the conjunctiva in cases that had a limbal-based flap using absorbable 6/0 vicryl. Subconjuctival dexamethasone 4 mg injection is given and tropicamide eye drops applied before the eye is padded. First-day assessment includes measuring visual acuity, IOP, wound site, bleb size and function. Slit lamp bio microscopy is essential in determining state of the eye, such as cornea clarity, depth of A/C, in addition to fundoscopy. Post-operative medications include steroid/antibiotic combination eye drops, a mydriatic and

**4. The procedure: Trabeculectomy with anti-fibrotic agent**

108 Advances in Eye Surgery

systemic antibiotic such as amoxicillin. Initial follow-up visit is after one week.

Intraoperative complication includes hemorrhage, which can be arrested and bleeding vessels cauterized. Shallow A/C on the table usually reforms; in the event of delayed reformation, saline can be injected after the outer sclera flap is sutured.

Post-operative complications include the following:


### **6. Conclusion**

POAG is a common cause of avoidable blindness in SSA. Due to socio-demographic reasons, patients have poor access to eye care and often present late. Trabeculectomy with antimeta‐ bolite is an acceptable procedure that offers good IOP control. Proper education of the patient and caregiver particularly on the goal of treatment is an essential component of management.
