INITIAL CLINICAL-EXPERIENCE WITH THE AHMED GLAUCOMA VALVE IMPLANT

PURPOSE: We studied the Ahmed Glaucoma Valve implant, an aqueous shunt ing device that has a unidirectional valve mechanism designed to preve nt postoperative hypotony in eyes with in tractable glaucoma. METHODS: In this multicenter, prospective clinical trial, we studied 60 eyes ( 60 patients) with increased intraocular pressure or glaucoma that had not responded to medical treatment, laser photocoagulation, or previou s glaucoma surgery, in which the Ahmed Glaucoma Valve implant was plac ed to decrease intraocular pressure. RESULTS: Success was defined as i ntraocular pressure less than 22 mm Hg and greater than 4 mm Hg for tw o months or longer, intraocular pressure that was lowered by at least 20% from preoperative values (in eyes with preoperative intraocular pr essures less than 22 mm Hg), and no additional glaucoma surgery or vis ually devastating complications. Cumulative probability of success at 12 months was 78%. Eight (13%) of 60 eyes had intraocular pressure les s than 5 mm Hg the first postoperative day, Two other eyes had shallow anterior chambers, which required anterior chamber reformation. The m ajor complications associated with the use of the valve were serous ch oroidal detachments in 13 eyes (22%), blockage of the tube in six eyes (10%), malposition of the tube in four eyes (7%), a suprachoroidal he morrhage in one eye (2%), and corneal graft rejections in three (19%) of 16 eyes with corneal grafts. CONCLUSIONS: Although the 12-month suc cess with the Ahmed Glaucoma Valve implant is similar to that reported for other drainage devices, the complications associated with overfil tration in the immediate postoperative period appear to be less freque nt than with other valved drainage devices, Randomized, prospective st udies to compare the Ahmed Glaucoma Valve implant with other drainage devices are needed to make clinical comparisons of the different devic es.