Abstract
Title: Evaluation of a modified graft-free technique of Ahmed glaucoma valve (AGV) implantation Purpose: To determine the outcome of AGV implanted via a scleral tunnel, without using any patch grafts. Method: Retrospective case series of 18 consecutive patients undergoing AGV via scleral tunnels in a single hospital from 2011-2015. Results: The mean follow-up was 1.7 ± 1.4 years. The mean age of the patients at the time of surgery was 73.4 ± 9.2 years old. The cases include 72% neovascular glaucoma, 11% primary open angle glaucoma, 6% posner schlossman, 6% pseudoexfoliation and 6% uveitic glaucoma. Mean intraocular pressures (IOPs) before and after AGV implant were 40.8 ± 11.9mmHg and 15.9 ± 7.9mmHg respectively. Median visual acuity before and after AGV implant were both counting fingers. There was no tube erosion noted, although 2 patients (11%) had end-plate erosion, requiring explantation of the AGV. Other post-operative complications (occurring at any point) include hyphaemas >1mm (33%), choroidal effusions (22%), shallow AC requiring healon injection (6%), tenon’s cyst requiring excision (6%) and fibrosed bleb requiring needling (6%). All hyphaemas and choroidal effusions resolved without intervention. Success at final follow-up (IOP between 5 and 21mm Hg with least 20% reduction from baseline IOP, without additional glaucoma surgery nor loss of light perception) was 72%. Conclusion: In this graft-free technique of AGV implantation, there were no tube erosions but 2 patients (11%) had end-plate exposure. This end-plate exposure rate is comparable to the range reported in traditional AGV implant using patch-grafts.