Incidence of disc hemorrhages in open-angle glaucoma before and after trabeculectomy

PURPOSE: To investigate the effects of reduction of intraocular pressure (IOP) by surgical intervention on the frequency of disc hemorrhages in eyes with primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG). DESIGN: Retrospective study. METHODS: We studied 99 eyes of 99 patients with POAG and 50 eyes of 50 patients with NTG, who underwent trabeculectomy with adjunctive mitomycin C (MMC) and were followed regularly at 1 to 3-month intervals at the Glaucoma Service of Gifu University Hospital. We applied Kaplan-Meier life-table analysis for the detection of disc hemorrhages before and after trabeculectomy. RESULTS: Trabeculectomy significantly reduced IOP (in POAG: 19.6 +/- 4.4 down to 11.1 +/- 4.2 mm Hg; in NTG: 15.3 +/- 1.5 down to 11.3 +/- 4.5 mm Hg; mean +/- SD). Life-table analysis revealed that the final cumulative probability of detecting a disc hemorrhage after surgery in POAG was 5.5 +/- 2.2% (calculated probability +/- SE) and was significantly lower than that (33.4 +/- 7.8%) before surgery (P < 0.0001, log-rank test). Likewise, the final probability after surgery in NTG was 23.1 +/- 6.3% and was significantly lower than that (42.1 +/- 8.8%) before surgery (P = 0.0063, log-rank test). CONCLUSIONS: IOP reduction via surgical intervention significantly decreases the frequency of disc hemorrhages in open-angle glaucoma patients.