Ahmed valve successful in lowering IOP in cases of 20 mm Hg or less but presents complications risk

J Glaucoma. 2009;18(9): 674-678.

In a recent study, more than half of patients implanted with an Ahmed glaucoma drainage device had surgical success, defined as IOP of 5 mm Hg or higher and 20% lower than before implantation (with or without hypotensive therapy), visual acuity light perception or better, and no additional glaucoma surgery.

The noncomparative retrospective case series looked at 63 patients who had 66 implantations of the Ahmed glaucoma drainage device (New World Medical). Preoperative IOP was 20 mm Hg or less in all patients.

The study found that at 12 months, 57.6% of cases were considered successful, and by final follow-up (mean 51 months), 53% of cases were surgical successes.

"In patients with IOPs of 20 mm Hg or less who require IOPs in the low teens and below, Ahmed [glaucoma drainage device] surgery does seem to be an effective option," the study authors wrote. "The success rates of surgery, however, must be balanced against the risk of complications."

Of the 63 patients, 14 (21.2%) underwent additional glaucoma surgery. Eight of these patients had a second Ahmed glaucoma drainage device implanted.