Long-term outcomes of Ahmed glaucoma valve implantation in refractory glaucomas

PURPOSE: To evaluate the long-term efficacy of in, traocular pressure (IOP) reduction and complications of Ahmed glaucoma valve (AGV) implantation (New World Medical, Inc, Rancho Cucamonga, California, USA) in refractory glaucoma. DESIGN: Retrospective cohort study. METHODS: Retrospective medical records from 64 patients (78 eyes) with refractory glaucoma who under went AGV implantation with a minimum of three years of follow-up were reviewed. Data regarding age, gender, race, eye laterality, specific glaucoma diagnosis, best-corrected visual acuity (BCVA), number of medications, lop, visual fields, surgical complications, and follow-up interval were collected from all visits and were analyzed. The primary outcome measure was cumulative probability of success defined as IOP of less than 21 mm Hg and of 5 mm Hg or more with a minimum of 15% reduction from baseline IOP, without additional glaucoma surgery or loss of light perception. Secondary outcomes included IOP and number of medications at three, six, 12, 24, 36, 48, and 60 months after surgery, surgical complications, and final BCVA. RESULTS: The cumulative probability of success was 80% and 49% at one and five years, respectively. IOP was reduced from a mean of 30.4 +/- 10.7 mm Hg to 17.0 +/- 5.0 mm Hg at 12 months and 15.9 +/- 3.0 mm Hg at 60 months (P<.001). The number of medications decreased from 3.2 +/- 1.0 medications at baseline to 1.6 +/- 0.4 at 12 months and 2.1 +/- 0.2 at 60 months (P<.001). Prior glaucoma surgery and the silicone type of AGV were statistically significant risk factors for failure (P<.001). CONCLUSIONS: Approximately 50% of single-plate AGV implantations in refractory glaucoma were considered successful after five years of follow-up. Prior glaucoma surgery was a statistically significant risk factor for failure.