Valve implant may control IOP in refractory glaucoma patients

Implanting the Ahmed glaucoma valve in eyes with refractory glaucoma results in successful IOP control in approximately 50% of cases out to 5 years postop, according to a study by researchers in California and Brazil.

However, "prior glaucoma surgery was a statistically significant risk factor for failure," the study authors said.

Carlos Souza, MD, and colleagues reviewed outcomes for 78 eyes of 64 patients implanted with a single-plate Ahmed glaucoma valve (AGV, New World Medical) for refractory glaucoma. All patients had at least 3 years of follow-up.

"The primary outcome measure was cumulative probability of success, defined as IOP of less than 21 mm Hg and of 5 mm Hg or more with a minimum of 15% reduction from baseline IOP, without additional glaucoma surgery or loss of light perception," the authors said.

At 1 year follow-up, the cumulative probability of success was 80%. Additionally, the average IOP had decreased from 30.4 mm Hg preoperatively to 17 mm Hg, and the number of medications used had decreased from 3.2 at baseline to 1.6, according to the study.

At 5 years, the cumulative probability of success was 49%, mean IOP had decreased to 15.9 mm Hg, and patients used an average of 2.1 glaucoma medications.

The study is published in the December issue of American Journal of Ophthalmology.