Medium to long term intraocular pressure control following small flap trabeculectomy (microtrabeculectomy) in relatively low risk eyes

Abstract

Aim - To determine the long term efficacy of small flap trabeculectomy (microtrabeculectomy) in terms of intraocular pressure (IOP) control in relatively low risk eyes. Method - A review of a case series of small flap trabeculectomy procedures performed on 36 eyes from 36 patients with a minimum follow up of 24 months (mean 50.8). Results - The mean (SD) intraocular pressures at presentation and preoperatively were 33.7 (7.5) and 24.6 (4.5) mm Hg. At 6 months, 1, 2, 3, 4, 5, and 6 years the mean (n, SD) IOPs (mm Hg) of those eyes followed to each time point were 11.9 (36, 4.6), 12.6 (36, 4.7), 13.2 (36, 4.6), 13.7 (29, 4.1), 13.2 (22, 4.0), 12.7 (15, 4.8), and 12.3 (8, 4.7) respectively. There was no significant difference in IOP levels at any of the analysis points by one way ANOVA. Kaplan-Meier analysis revealed survival rates of 80% at 4 years and 75% at 5 years when any postoperative IOP > 20 mm Hg is considered a failure, and 50% at 6 years when any IOP > 15 mm Hg is classed as a failure. Conclusion - Small flap trabeculectomy (microtrabeculectomy) is effective at reducing IOP in low risk glaucoma eyes with IOP control similar to previous reports of filtering surgery utilising larger scleral trapdoors.