Conventional trabeculectomy aims to control IOP by way of a guarded fistula between the anterior chamber and sub-conjunctival space via leakage past the scleral flap. The resulting bleb is often seen to form under the anterior conjunctiva, where Tenon's layer and the conjunctival tissue are thinnest, predisposing patients to bleb-related complications at or near the limbus. Complications include cystic bleb formation, blebitis, endophthalmitis, dellen ulcer and bleb dysaesthesia, the use of anti-metabolites often compounding these problems.