Abstract
Abstract: :
Purpose: To compare short–term intraocular pressure (IOP) control of the silicone versus polypropylene Ahmed valve implants in patients with refractory glaucoma. Methods: The hospital converted from polypropylene to silicone Ahmed valve implants in February 2003. 27 eyes which had polypropylene Ahmed valve implants inserted before the conversion and 27 eyes which had silicone Ahmed valve after the conversion were retrospectively reviewed. Exclusion criteria were prior drainage device or cyclodestructive procedures. Surgical success was defined as an IOP reduction ≥ 30% and final IOP > 5 mmHg and < 22 mm Hg, without devastating complications or additional surgical interventions for IOP control. Study groups were compared with Students’ t–tests and Kaplan–Meier survival analysis. Results: The 6 months success rates for silicone and polypropylene Ahmed valve implants were 63.0% and 70.4%, respectively (p=0.77), complication rates were 7.4% for each group, and hypotony rates were 22.2% and 11.1%, respectively (p = 0.47). Table of mean postop IOPs:
The silicone Ahmed valve group was using less glaucoma medications for IOP control than the polypropylene group at last follow–up (1.4 ± 0.3 vs. 2.0 ± 0.3, p ≤ 0.05). Conclusions:The silicone Ahmed valve appears to have a lower IOP than the polypropylene Ahmed valve during the immediate postoperative period. In addition, less glaucoma medications were required at last follow–up. Surgeons converting to the newer silicone Ahmed valve for patients with refractory glaucoma need to be aware of these differences.
Keywords: intraocular pressure