Efficacy and complications after trabeculectomy with mitomycin C in normal-tension glaucoma

Purpose: To evaluate the efficacy of and complications after trabeculectomy using mitomycin C (MMC) in Japanese normal-tension glaucoma (NTG) patients by a retrospective analysis based on the Kaplan-Meier life table method. Methods: Clinical records of 39 NTG patients who underwent trabeculectomy with 0.04 % MMC and had postoperative follow-up periods of 3 years or more (50.5 +/- 8.4 months, mean +/- SD) were reviewed. Postoperative intraocular pressure (IOP) at every 1 or 2 months, complications, visual acuity, and visual field at every 6 months were recorded. Results: IOP significantly decreased from 15.9 +/- 1.9 preoperatively to 8-11 mmHg throughout the postoperative follow-up period (P < 0.0001). The life table analysis, in which failure of IOP control was defined as an IOP above a level either 30 % or 20 % lower than the preoperative IOP at three consecutive visits, showed a cumulative survival rate of 39.4 +/- 7.8% (mean +/- SEM) or 41.3 +/- 8.9 %, respectively, at 4 years after surgery. Mean deviation of the visual field results did not significantly change (P > 0.5). The cumulative survival rate from postoperative late-onset hypotony was 74.7 +/- 6.3 % at 4 years after surgery. Postoperative complications observed were shallow anterior chamber (six eyes), choroidal detachment (nine eyes), hypotonous maculopathy (seven eyes), bleb teak (one eye), cataract development (three eyes), and blebitis (two eyes). No eyes developed endophthalmitis. Conclusions: In NTG patients, trabeculectomy with MMC showed significant efficacy in reducing IOP up to 4 years after surgery. Since risks of postoperative complications are unavoidable, indications for surgery should be carefully considered, and careful follow-up is necessary to avoid severe postoperative complications. (c) Japanese Ophthalmological Society 2005.