Surgical Outcome of Replacing a Failed Ahmed Glaucoma Valve by a Baerveldt Glaucoma Implant in the Same Quadrant in Refractory Glaucoma

PURPOSE: The purpose of this study was to describe the surgical technique and outcomes in eyes that underwent surgery to replace a failed Ahmed valve by a Baerveldt glaucoma implant in the same quadrant. METHODS: This study was a retrospective case series of 9 patients. Parameters analyzed include age, glaucoma type, prior surgery, complications, intraocular pressure (IOP), visual acuity, and number of glaucoma medications before and after the surgery. Surgical success was defined as having either an IOP below 21 mm Hg or a 20% IOP reduction, with or without hypotensive agent. RESULTS: The mean follow-up duration was 47 months. After surgery, at the time of final follow-up, the mean IOP decreased from 29.9 mm Hg to 16.7 mm Hg (36% of mean IOP reduction; P=0.008). There was a significant reduction of hypotensive agents from a mean of 4.33 to 2.22 (P=0.02). The visual acuity did not have a significant deterioration (P=0.07). In the final visit, 5 of 9 patients met total success criteria and 2 patients were qualified successes. Two cases failed totally after 69 and 125 months of follow-up. The cumulative probability of total success after 6 months was 76% and this rate remained stable until the sixth year. One patient had bullous keratopathy. Two patients had early postoperative pressure spikes: the first patient was treated by trabeculectomy, and the second by vitrectomy. CONCLUSIONS: A replacement of the failed Ahmed glaucoma valve by a new Baerveldt glaucoma implant in the same quadrant can be a reasonable choice to control refractory glaucoma.