Initial clinical experience with the Ahmed glaucoma valve implant in the management of neovascular glaucoma

Purpose: To examine the Ahmed valve implant in the management of intraocular pressure (IOP) in patients with movascular glaucoma (NVG). Methods: We retrospectively reviewed all patients with NVG who underwent placement of an Ahmed valve implant between 7/94 and 11/95. Neovascular glaucoma was characterized by elevated IOP and neovascularization of the iris and/or the angle structures. A qualified versus complete success was determined by the maintenance of IOP less than 21 mmHg with and without medications, respectively. Results: Sixteen patients received the Ahmed valve implant for NVG. The mean pre-operative and post-operative IOPs were 39.7mmHg and 19.9mmHg, respectively. Seven of 16(43.8%) eyes were complete successes, and 3 of 16(18.8%) were qualified successes. Seven of 16 required major interventions. Four (25.0%) developed flat or shallow anterior chambers, and a viscoelastic agent was placed in three of these eyes Two eyes received post-operative tissue plasminogen activator infusion into the anterior chamber and one required direct tube irrigation to open obstructed implants Seven of 16 patients required at least two medications for post-operative IOP control. Two patients had valve failure and required transcleral YAG cyclophotocoagulation. The median pre-operative and post-operative visual acuity was 5/200 and HM, respectively. The median followup time was 2.5 months. Conclusion: Neovascular glaucoma may be managed by the Ahmed glaucoma valve. The problem of immediate post-operative hypotony and shallow/flat anterior chamber is not eliminated by the valve implant. Finally, several patients developed complete obstruction of the Ahmed valve implant requiring additional surgical intervention.

Duke Scholars

Author Paul Pue-Jung Lee Ophthalmology, Glaucoma