Purpose: To evaluate the long-term intraocular pressure (IOP) control and to identify risk factors for failure of repeat trabeculectomy with mitomycin C (MMC) in patients with open-angle glaucoma.
Design: Retrospective case-control study.
Methods: Seventy-five eyes (67 patients) that had undergone repeat trabeculectomy with MMC were matched to 75 eyes (64 patients) that had undergone initial trabeculectomy with MMC according to age, gender, race, diagnosis, preoperative IOP, number of glaucoma medications, and lens status in an institutional setting. Surgical successes were defined as: 1) IOP < or =18 mm Hg and > or = 20% reduction in IOP, 2) < or = 15 mm Hg IOP and > or = 25% reduction in IOP, and 3) < or = 12 mm Hg IOP and > or = 30% reduction in IOP from baseline, with or without glaucoma medications, and were assessed by Kaplan-Meier survival analyses. Risk factors for failure in the repeat trabeculectomy group were analyzed by the Cox proportional hazard regression model. The main outcome measures were success rate, number of medications, and visual acuity.
Results: Eyes that underwent initial trabeculectomy with MMC had a statistically significantly higher cumulative surgical success rate than those that underwent repeat trabeculectomy with MMC at 3 years according to criteria B (61.3% vs 41.3%; P = .022) and C (52.0% vs 32.0%; P = .021). In eyes that underwent repeat trabeculectomy, younger age and requirement of laser suture lysis were significant risk factors for surgical failure. Eyes that underwent initial trabeculectomy required a statistically fewer number of medications than eyes that underwent repeat trabeculectomy (0.6 vs 1.2; P = .013).
Conclusions: Repeat trabeculectomy with MMC is less successful at achieving IOP reduction in open-angle glaucoma than is initial trabeculectomy with MMC at 3 years or more.