Valve membrane adhesion as a cause of Ahmed glaucoma valve failure.
OBJECTIVE
The purpose of this study was to describe a possible mechanism of failure of the Ahmed glaucoma valve (AGV; New World Medical, Rancho Cucamonga, CA).


METHODS
Two AGVS that failed to control intraocular pressure (IOP) were examined. In vivo examination consisted of unroofing the capsule surrounding the implant and injecting fluorescein-stained balanced salt solution into the tube. In one case the entire implant was removed and examined in vitro, and in the other case only the valve portion was removed.


RESULTS
No flow in either case extended beyond the valve. In both cases, the membrane valve system was found to be fused and could not be pulled apart.


CONCLUSIONS
Failure of the AGV may occur due to adhesion of the valve membranes.
Feldman
R M
RM
Department of Ophthalmology and Visual Science, University of Texas Health Science Center, Houston, USA.
el-Harazi
S M
SM
Villanueva
G
G
D000867:Anterior Chamber / Q000601:surgery; D004322:Drainage / Q000295:instrumentation*; D005260:Female; D019793:Fluorescein; D005452:Fluoresceins; D005500:Follow-Up Studies; D005901:Glaucoma / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000209:etiology; D011183:Postoperative Complications; D019736:Prostheses and Implants / Q000009:adverse effects*; D011475:Prosthesis Failure; D012826:Silicone Elastomers / Q000009:adverse effects*
D005452:Fluoresceins; D012826:Silicone Elastomers; D019793:Fluorescein