VALVE MEMBRANE ADHESION AS A CAUSE OF AHMED GLAUCOMA VALVE FAILURE

Purpose: The purpose of this study was to describe a possible mechanis m of failure of the Ahmed glaucoma valve (AGV; New World Medical, Ranc ho Cucamonga, CA). Method: Two AGVS that failed to control intraocular pressure (IOP) were examined. In vivo examination consisted of unroof ing the capsule surrounding the implant and injecting fluorescein-stai ned balanced salt solution into the tube. In one case the entire impla nt was removed and examined in vitro, and in the other case only the v alve portion was removed. Result: No flow in either case extended beyo nd the valve, In both cases, the membrane valve system was found to be fused and could not be pulled apart. Conclusion: Failure of the AGV m ay occur due to adhesion of the valve membranes.