Three-year outcomes of trabeculectomy and Ahmed valve implant in patients with prior failed filtering surgeries

To compare three-year surgical outcomes of trabeculectomy versus Ahmed valves in patients with prior failed trabeculectomy. This is a longitudinal retrospective comparative study of one-hundred twenty adult patients with prior failed trabeculectomy who underwent a repeat trabeculectomy or Ahmed valve implant. Demographic and clinical data were collected up to 3 years on all study participants at the Kresge Eye Institute from 2004 to 2016. Visual acuity, intraocular pressure, number of intraocular pressure reducing medications, and success rates at various time points up to 3 years after repeat surgery were the main outcome variables. Sixty-five and sixty eyes were included in the trabeculectomy and the Ahmed valve groups, respectively. Baseline intraocular pressure significantly decreased in both groups at 3 years (p   0.05). There was no statistically significant difference between the two groups in visual acuity, percentage of intraocular pressure reduction, number of medications, or success rates at any follow-up time points (p > 0.05 for all). After 3 years, both trabeculectomy and Ahmed valves significantly reduced intraocular pressure from baseline, but with relatively similar number of medications compared to baseline. There was no significant difference in any outcome measure between trabeculectomy and Ahmed valves at any follow-up time points. These results may suggest neither trabeculectomy or Ahmed valves are superior in patients with previously failed trabeculectomies.