Age over 46 years does not affect the pressure lowering effect of trabeculectomy in primary open angle glaucoma

Previous reports have suggested that the success rate for trabeculectomy is poorer in younger age groups but these studies often have heterogeneous groups representing different types of glaucoma with variable surgical prognosis. Therefore, the relation between age and the success of trabeculectomy in the single diagnostic category of primary open angle glaucoma (POAG) without identifiable risk factors was examined for failure in the age range 46-85 years.

The records of 208 patients who had undergone a first trabeculectomy for POAG were examined retrospectively. Age ranged from 46 to 85 (mean 66.7 years). The outcome of surgery was examined at final available follow up and at 1 and 2 years after surgery. Trabeculectomy was considered a success if intraocular pressure was < or = 21 mm Hg with or without additional medical treatment ("cumulative" success) and an "absolute" success if intraocular pressure was < = 21 mm Hg without additional medical treatment.

Cumulative success for trabeculectomy was 92.3% at final follow up and 96.6% at 2 year follow up; absolute success rate was 66.3% at final follow up and 71.6% at 2 years. There was no significant trend for greater success of trabeculectomy in the older age groups (cumulative success at 2 year follow up, chi 2 for linear trend 1.07 (p = 0.3) nor was the drop in intraocular pressure following surgery significantly greater with increasing age (analysis of variance for intraocular pressure lowering from presentation to 2 years' follow up (Kruskal-Wallis, t = 5.9, p = 0.55). Patients with pseudoexfoliation were excluded from the main analysis as these patients have been shown to have a lower final intraocular pressure following trabeculectomy, a finding which was confirmed in this study.