Follow-up of the original cohort with the Ahmed glaucoma valve implant

PURPOSE: To study the long-term results of the Ahmed glaucoma valve implant in patients with complicated glaucoma in whom short-term results have been reported. METHODS: In this multicenter study, we analyzed the long-term outcome of a cohort of 60 eyes from 60 patients in whom the Ahmed glaucoma valve was imp lanted. Failure was characterized by at least one of the following: intraoc ular pressure greater than 21 mm Hg at both of the last two visits less tha n 6 mm ng at both of the last two visits, loss of light perception, additio nal glaucoma surgery, devastating complications, and removal or replacement of the Ahmed glaucoma valve implant. Devastating complications included ch ronic hypotony, retinal detachment, malignant glaucoma, endophthalmitis, an d phthisis bulbi; we also report results that add corneal complications (co rneal decompensation or edema, corneal graft failure) as defining a devasta ting complication. RESULTS: The mean follow-up time for the 60 eyes was 30.5 months (range, 2. 1 to 63.5). When corneal complications were included in the definition of f ailure, 26 eyes (43%) were considered failures. Cumulative probabilities of success at 1, 2, 3, and 4 years were 76%, 68%, 54%, and 45%, respectively. When corneal complications were excluded from the definition of failure, 1 3 eyes (21.5%) were considered failures. Cumulative probabilities of succes s at 1, 2, 3, and 4 years were 87%, 82% 76%, and 76%, respectively. Most of the failures after 12 months of postoperative follow up were because of co rneal complications. CONCLUSIONS: The long-term performance of the Ahmed glaucoma valve implant is comparable to other drainage devices. More than 12 months after the impl antation of the Ahmed glaucoma valve implant, the most frequent adverse out come was corneal decompensation or corneal graft failure. These corneal pro blems may be secondary to the type of eyes that have drainage devices or to the drainage device itself. Further investigation is needed to identify th e reasons that corneal problems follow drainage device implantation. (C) 19 99 by Elsevier Science Inc. All rights reserved.