Trabeculectomy Outcomes after Glaucoma Drainage Device Surgery

PURPOSE: To evaluate outcomes of trabeculectomy with adjunctive mitomycin C in patients with uncontrolled intraocular pressure (IOP) after glaucoma drainage device implantation. MATERIALS AND METHODS: Consecutive patients who had undergone a trabeculectomy after GDD were reviewed. The primary outcome was surgical success with stratified IOP targets based on the following criteria: (A) IOP<18 mm Hg and IOP reduction of 20%; (B) IOP<15 mm Hg and IOP reduction of 25%; (C) IOP<12 mm Hg and IOP reduction of 30%. Secondary outcomes were number of glaucoma medications, complications, and need for additional glaucoma surgery. RESULTS: Twenty eyes (19 patients) were included for analysis. Median follow-up and age were 3.7 years (range, 1.1 to 10.2 y) and 64.2 years (range, 25.2 to 85.6 y), respectively. Mean IOP (±SD) has dropped from 19.3±4.2 mm Hg preoperatively to 9.8±2.2 mm Hg at 1 year, 8.8±3.2 mm Hg at 3 years and 8.4±1.5 mm Hg at 5 years (P<0.001 for all). Hypotony maculopathy was the only serious complication (2/19 patients; 10%) that needed surgical revision. The cumulative success rate (±SD) for criterion A and B were 73.2% (±10.0%) and 68.2% (±9.5%), respectively, between the first and fifth year of follow-up, for criterion C it was 49.1% (±10.8%) at the first year and 32.7% (±12%) between the second and fifth year of follow-up. CONCLUSIONS: Trabeculectomy is a viable surgical option to treat IOP that is uncontrolled after GDD implantation.