Primary trabeculectomy with mitomycin C: safety and efficacy at 2 years

Abstract

Purpose: To examine the rates of intermediate-term intraocular pressure (IOP) control after trabeculectomy with adjunctive mitomycin C (MMC) and assess for associated complications.

Methods: Medical records of patients undergoing primary trabeculectomy with MMC at Concord Repatriation Hospital, Sydney between January 1997 and December 2005 were reviewed. All eyes with a minimum of 2-year follow up were included. Follow-up data were collected in a standardized form on postoperative IOP, bleb-related and other complications. Success was measured as IOP ≤ 18 mmHg and ≥ 6 mmHg (criteria 1) with (qualified success) or without (absolute success) the use of glaucoma medications. A secondary outcome measure was an IOP reduction of greater than 20% from baseline (criteria 2). Eyes with preoperative IOP of 18 mmHg or less were included, but also analysed separately to those eyes with preoperative IOP above 18 mmHg.

Results: Sixty eyes from 42 patients were included in the study, with 3-year follow up on 48 eyes. Mean preoperative IOP was 25.3 mmHg (range 8-45) and mean postoperative IOP was 14.0 mmHg at 1- and 2-year follow up, and 14.7 mmHg at 3 years (ranges: 3-31, 4-30 and 8-45 mmHg respectively). Cumulative success for criteria 1 was 85.0% at 2 years and 83.3% at 3 years, and for criteria 2 it was 80.0% and 79.2%, respectively. The number of eyes on glaucoma medications was reduced from 51 preoperatively to 30 at 3 years. Complications were infrequent. There was one eye with a shallow anterior chamber beyond the immediate postoperative period. One eye required cataract surgery at 1-year follow up. Subgroup analysis was performed using the first operated eye only, and results did not differ significantly from overall results.

Conclusion: MMC-augmented trabeculectomy can significantly reduce IOP in the short and intermediate term, with a favourable safety profile.