Comparison of silicone and polypropylene Ahmed Glaucoma Valve implants

Abstract

Purpose: To compare the efficacy and safety of silicone and polypropylene Ahmed Glaucoma Valves (AGVs) in patients with refractory glaucoma.Methods: A retrospective chart review of 180 eyes of 166 patients who underwent AGV implantation with a minimum follow-up period of 3 months was performed. All patients who underwent implantation of either the AGV model S-2 (polypropylene) or model FP-7 (silicone) were included, unless previous laser cyclophotocoagulation had been performed. the primary outcome measures were the change in intraocular pressure (IOP) and visual acuity after surgery and the rate of postoperative complications.Results: No significant differences were seen in the baseline characteristics of patients in each group. Baseline IOP was statistically equivalent in the 2 groups (silicone = 33.8 +/- 11.9 mm Hg, polypropylene 33.0 +/- 10.3 mm Hg, P = 0.6). A significant reduction in IOP from baseline was achieved after both silicone and polypropylene AGV implantation (silicone = -17.7 +/- 11.8 mm Hg, polypropylene = -17.7 +/- 11.3 mm Hg, both P < 0.00005). However, there was no statistically significant difference in IOP decrease between the 2 groups at any follow-up visit (all P > 0.09). the mean number of postoperative antiglaucoma medications was also similar in the silicone and the polypropylene AGV groups at each time point (all P > 0.2). the rate of complications and the change in visual acuity did not differ between the 2 groups (P > 0.6 and P > 0.3, respectively).Conclusions: Silicone and polypropylene AGVs have similar results with respect to both safety and efficacy in the treatment of patients with refractory glaucoma.