The Ahmed Versus Baerveldt Study

Objective: To compare 2 commonly used aqueous drainage devices for the treatment of refractory glaucoma. Design: International, multicenter, randomized trial. Participants: Patients aged 18 years or older with uncontrolled or high-risk glaucoma refractory to maximum medical therapy, many of whom had failed trabeculoplasty and trabeculectomy. Methods: Eligible patients were randomized to an Ahmed-FP7 valve implant (New World Medical, Inc., Rancho Cucamonga, CA) or a Baerveldt-350 implant (Abbott Medical Optics, Inc., Santa Ana, CA) using a standardized surgical technique. Main Outcome Measures: The primary outcome was failure, defined as intraocular pressure (IOP) outside of the target range (5e18 mmHg, with -20% reduction from baseline) for 2 consecutive visits after 3 months, visionthreatening complications, de novo glaucoma procedures, or loss of light perception. Secondary outcome measures include IOP, medication use, visual acuity, complications, and interventions. Results: A total of 238 patients were enrolled and randomized; 124 received the Ahmed implant and 114 received the Baerveldt implant. Baseline characteristics were similar in both groups. Half the study group had secondary glaucoma, and 37% had previously failed trabeculectomy. The mean preoperative IOP was 31.4 +/- 10.8 mmHg on 3.1 +/- 1.0 glaucoma medications. Median baseline Snellen visual acuity was 20/ 100. At 3 years, the cumulative probability of failure was 51% in the Ahmed group and 34% in the Baerveldt group (P 0.03). Mean IOP was 15.7 +/- 4.8 mmHg in the Ahmed group (49% reduction) and 14.4 +/- 5.1 mmHg in the Baerveldt group (55% reduction; P 0.09). Mean number of glaucoma medications was 1.8 +/- 1.4 in the Ahmed group (42% reduction) and 1.1 +/- 1.3 in the Baerveldt group (65% reduction; P 0.002). There was a moderate but similar decrease in visual acuity in both groups (P< 0.001). The 2 groups had similar complication rates (52% Ahmed, 62% Baerveldt; P 0.12); however, the Baerveldt group had a higher rate of hypotony-related vision-threatening complications (0% Ahmed, 6% Baerveldt; P 0.005). More interventions were required in the Baerveldt group, although the difference did not reach statistical significance (38% Ahmed, 50% Baerveldt; P 0.07). Most complications were transient, and most interventions were slit-lamp procedures. Conclusions: Both devices were effective in reducing IOP and glaucoma medications. The Baerveldt group had a lower failure rate and required fewer medications than the Ahmed group after 3 years, but it experienced more hypotony-related vision-threatening complications. (C) 2013 by the American Academy of Ophthalmology.