RESUMEN
PURPOSE: To evaluate the outcome of Ahmed valve implantation as a primary or secondary glaucoma surgery to treat refractory glaucoma patients. METHODS: A total of 101 eyes of 101 patients with refractory glaucoma, who received Ahmed valve implantation between March 1995 to September 2004 were included. We divided cases into primary surgery group, who had no trabeculectomy, and secondary surgery group, who had trabeculectomy before Ahmed valve implantation. Successful operation was defined as having the following outcomes: (1) postoperative intraocular pressure (IOP) sustained between 5 and 21mmHg and reduced 30% from the baseline IOP with or without medication, (2) no visual decline due to IOP or complications, and (3) no additional filtering surgery. Clinical records were reviewed, and IOP, antiglaucoma medications, and complications were recorded. Kaplan-Meier survival analysis was used to calculate the overall probability of success. RESULTS: In primary surgery group, overall success rate was 57.6%, 46.7%, 39.7%, and 39.7% at 1, 3, 5, and 7 years, respectively. In secondary surgery group, overall success rate was 67.8%, 58.1%, 52.4%, and 43.5% at the same time points. There was, however, no statistical difference in success rates between two groups. The incidence of complications were as follows: 4.2% of endophthalmitis, 4.2% of valve exposure, 4.2% of hypotony was found in the primary surgery, and 3.8% of endophthalmitis, 1.9% of valve exposure, 9.4% of hypotony were found in the secondary surgery. There were no statistical differences in the incidences of complications between the two groups. CONCLUSIONS: Ahmed valve implantation was effective for IOP control in refractory glaucoma patients. Success rate did not show significant difference between primary and secondary Ahmed valve implantation group.