Comparison of Silicone- and Porous-Plate Ahmed Glaucoma Valves

PURPOSE: Our aim was to evaluate and compare the clinical outcomes after implantation of the silicone-plate (model FP7) and porous polyethylene-plate (model M4) Ahmed Glaucoma Valves. PATIENTS AND METHODS: This was a prospective, multicenter, comparative series. A total of 52 eyes (52 patients) were treated with either the silicone or porous plate Ahmed Glaucoma Valve implant. Hypertensive phase was defined as intraocular pressure >21 mmHg during the first 3 months postoperatively. Success was defined as 5 mmHg ≤intraocular pressure ≤21 mmHg (with or without additional glaucoma medications), without loss of light perception and without additional glaucoma procedures. Patients were monitored for 1 year after surgery. RESULTS: The pre-operative intraocular pressure was 29.9 ± 6.6 mmHg and 33.8 ± 10.5 in the silicone-plate and porous-plate groups, respectively (P = 0.118). At 12 months after surgery, the mean intraocular pressure was 13.6 ± 4.7 mmHg in the silicone-plate group and 17.9 ± 10.9 mmHg in the porous-plate group (P = 0.141). The mean number of glaucoma medications at 12 months was 1.64 ± 1.40 mmHg and 1.89 ± 1.54 mmHg in the silicone- and porous-plate groups, respectively (P = 0.605). Hypertensive phase was not significantly different in the two groups (50.0% of the silicone-plate and 57.7% of the porous-plate groups, P = 0.578). At 12 months after surgery, the percent success for the silicone-plate and porous-plate groups was 88.5% and 53.8%, respectively (P = 0.005). Complications were similar in the two groups. CONCLUSION: The porous-plate Ahmed Glaucoma Valve showed similar average intraocular pressure reduction compared with the silicone-plate model. At 12 months after surgery, there was a significantly lower success rate in the porous-plate compared with the silicone-plate group.