Outcomes of Ahmed Glaucoma Valve Revision in Pediatric Glaucoma

Abstract

Encapsulation of the Ahmed glaucoma valve (AGV) plate is a common cause for postoperative elevation of intraocular pressure, especially in children. Many reports have described the outcomes of AGV revision in adults. However, the outcomes of AGV revision in children are poorly documented. The aim of this study was to determine the outcomes of AGV revision in children. Retrospective cross-sectional study. A retrospective chart review of patients less than 15 years of age who underwent AGV revision with a minimum postoperative follow-up of 6months was conducted. Outcome measures included reduction in intraocular pressure from baseline, survival analysis, and reduction in the number of antiglaucoma medications. Postoperative complications were also noted. Complete success was defined as an IOP of 21mm Hg or less without medications, while qualified success was defined as having an IOP of 21mm Hg or less with medications. A total of 44 eyes met the inclusion criteria. Primary congenital glaucoma was present in 39 eyes (88.6%), aphakic glaucoma in 4 eyes (9.1%), and Peters anomaly-associated glaucoma in 1 eye (2.3%). The mean number of previous surgeries was 1.4, and the mean age was 6.7 years (range, 1.9-13 years) with a median follow-up of 12months (range, 6-24months). The IOP was reduced from a preoperative mean of 30.4 (± 10.3) to 24.9 (± 10.6) mm Hg at 6months postoperatively. Kaplan-Meier analysis showed that the complete success rate at 1month was 100% followed by a rapid decline at 6months to 38.6%, 27.7% at 1 year, and 5.5% at 2 years. Qualified success rate was 100% at 1month followed by a 6-month and 1-year survival rate of approximately 50% and a 2-year survival rate of approximately 16%. The median survival time was 14months. No specific risk factors for failure were identified. Visual acuity remained unchanged following revision. The most common complication was recurrence of encapsulation with elevated IOP (15.9%). Other complications included hyphema (n= 3; 6.8%), endophthalmitis (n= 1; 2.3%), wound leak (n= 1; 2.3%), and choroidal detachment (n= 2; 4.5%). Although the short-term success rate of AGV revision in children is high, with longer follow-up the success rate decreases significantly.