A Comparative Study of Small Incision Trabeculectomy Avoiding Tenon's Capsule With Conventional Trabeculectomy

BACKGROUND AND OBJECTIVE: The purpose of this study was to compare the results of small incision trabeculectomy (SIT) avoiding Tenon's capsule vis-à-vis conventional trabeculectomy, and find a safe, effective alternative to conventional trabeculectomy with or without pharmacological wound modulation. PATIENTS AND METHODS: A controlled prospective study was conducted on 80 consecutive open-angle glaucoma patients requiring glaucoma filtration surgery. They were divided into two groups: Group I (n = 40): patients undergoing conventional trabeculectomy; and Group II (n = 40): patients undergoing limbal approach SIT. Patients were followed up serially for a minimum of 12 months and their intraocular pressure was monitored. Success of the procedure was defined as an intraocular pressure (IOP) <22 mm Hg with no additional antiglaucoma medication or surgery, and achieving at least a 30% reduction from the initial IOP at which optic disc cupping and/or visual field changes occurred. RESULTS: A significant fall (P <0.0001) in the final mean IOP was present in both groups at all time intervals in comparison to their preoperative values. The final mean intraocular pressure achieved with conventional trabeculectomy was 18.90 +/- 4.86 mm Hg versus 16.60 +/- 5.93 mm Hg with SIT. The final success rate of 90% was obtained with SIT vs 80% with conventional trabeculectomy. No major complications were encountered with either procedure although complications such as shallow anterior chamber and progression of cataractogenesis were seen more often in patients undergoing conventional trabeculectomy. CONCLUSION: Small incision trabeculectomy avoiding Tenon's capsule is a low-cost and safe alternative to conventional trabeculectomy that effectively reduces IOP in 90% of cases. The use of a small 2.5 mm limbal incision, which obviates the dissection of Tenon's capsule and absence of any major complication, suggests that this procedure be used more often in glaucomatous eyes needing filtering surgery.