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Ahmed valve
Glaucoma drainage implant with a flow restrictor mechanism to prevent early postoperative hypotony.
Full Definition
An Ahmed valve is a type of glaucoma drainage device (GDD) that features a silicone plate connected to a tube with an integrated valve mechanism. Unlike other drainage implants, it includes a venturi-type flow restrictor that automatically regulates aqueous outflow based on intraocular pressure, reducing the risk of immediate postoperative hypotony. The device is available in pediatric and adult sizes and is particularly useful for complex or refractory glaucoma cases where conventional filtration surgery has failed.
Usage
Usage note: Named after inventor Dr. Sami Ahmed; capitalize the 'A' in Ahmed when referring to the specific device.
In Context
- "An Ahmed valve was implanted in the superotemporal quadrant following failed trabeculectomy." — Surgical report
- "The patient's Ahmed valve required revision due to tube malposition." — Clinical progress note
Also known as
Ahmed glaucoma valve
AGV
Don't confuse with
Baerveldt implant
Molteno implant