Outcomes of Ahmed valve surgery for refractory glaucoma in Dhahran, Saudi Arabia

AIM: To evaluate the outcomes of Ahmed glaucoma valve(AGV) implantation surgery for refractory glaucoma.METHODS: This one-armed historical cohort study was conducted in 2011. Refractory glaucoma was defined as eyes with an intraocular pressure(IOP) greater than21 mm Hg with maximally tolerated glaucoma medications, failed surgeries, or both. For all eyes with refractory glaucoma that underwent AGV implantation,data were collected on IOP, the best corrected visual acuity(BCVA) and glaucoma medications preoperatively and 4, 6, 12, 24 and 56 wk postoperatively. Logarithm values of IOP were calculated and compared. RESULTS: The study group was comprised of 30patients(30 eyes, 16 males and 14 females) with refractory glaucoma. Mean preoperative IOP was 39.3 ±13.8 mm Hg. Postoperative mean IOP was 15.7±7.1 mm Hg,19.6 ±12.8 mm Hg and 13.9 ±14.2 mm Hg at 12, 24 and56 wk respectively. BCVA was ≥6/60 in 11 eyes preoperatively, and five eyes had BCVA ≥6/60 at 56 wk postoperatively. Preoperatively, more than four medications were used to treat glaucoma in 21 eyes. At12 wk postoperatively, no medications were required to control IOP in 20 eyes. At 56 wk postoperatively, at least one medication was required to control IOP in 10 eyes.Over the entire follow up period, four eyes were treated with yttrium aluminium garnet(YAG) laser and 14 eyes required a second surgery. The AGV was removed in four eyes.CONCLUSION: AGV implantation reduced IOP and the number of medications required to control refractory glaucoma. However, there was a higher risk of decreased vision. Long-term follow up and prompt intervention are recommended.