Comparison of Ahmed glaucoma drainage implant outcomes in the anterior chamber versus pars plana.

OBJECTIVE: To compare long-term outcomes of eyes undergoing Ahmed glaucoma drainage implants in the anterior chamber versus the pars plana.Retrospective cohort study. PARTICIPANTS: Operated patients were divided into anterior-chamber or pars plana groups. METHODS: Follow-up data included intraocular pressure (IOP), need for antiglaucoma medications (AGMs), and postoperative complications. Treatment success was evaluated based on the following criteria: IOP ≤21 mm Hg and no AGM use, IOP ≤21 mm Hg with or without AGM use, IOP ≤18 mm Hg and no AGM use, IOP ≤18 mm Hg with or without AGM use, IOP ≤15 mm Hg and no AGM use, and IOP ≤15 mm Hg with or without AGM use. RESULTS: A total of 170 eyes were selected and split into an anterior-chamber group (n = 57) and a pars plana group (n = 113). No differences between groups were found on the decrease in IOP (p = 0.612) or number of AGMs (p = 0.695) in the postoperative period. No differences regarding corneal decompensation (p = 0.554) or retinal detachment (p = 0.168) were observed between groups. The 1-year success rates for all the criteria were, respectively, 89%, 96%, 88%, 92%, 88% and 90%; the 3-year success rates for all the criteria were, respectively, 33%, 61%, 32%, 55%, 28%, and 45%; and the 5-year success rates for all the criteria were, respectively, 7%, 48%, 7%, 36%, 4% and 17%. CONCLUSIONS: No differences between the groups were observed for long-term outcomes of IOP, AGM use, or postoperative complications. Success rates were comparable between groups, decreased along the follow-up time, and were higher when associated with AGM use.