Surgical Results of Ahmed Glaucoma Valve Implantation in One-chamber Eyes

Abstract

Precis: Ahmed glaucoma valve (AGV) implantation in eyes with damaged iris-lens diaphragms ("1-chamber" eyes) resulted in mean intraocular pressure (IOP) and antiglaucoma medications decreases of 66% and 59% (P<0.0001 for both), respectively, at the mean 23-month follow-up.

Purpose: The purpose of this study was to report the results of AGV implantation with pars plana tube insertion to control IOP in glaucomatous eyes with damaged iris-lens diaphragms ("1-chamber" eyes).

Methods: The medical records of 52 consecutive glaucomatous 1-chamber eyes (48 Japanese patients, mean age±SD, 76.0±11.2 y) were retrospectively reviewed. Other than aphakic eyes, eyes were defined as having 1 chamber if intraocular lenses (IOLs) were sclerally or intrasclerally fixated, IOLs were fixed on-the-bag due to posterior capsular defects, vitreous collapse into the anterior chamber resulted from Zinn zonular dialysis, and phacodonesis or IOL-donesis required lens/IOL explantation during AGV implantation. The data collected were preoperative/postoperative IOPs, numbers of antiglaucoma medications, visual acuity, anterior chamber flare, visual field mean deviation, corneal endothelial cell density, and surgical complications/interventions.

Results: The preoperative IOP (28.5±9.4 mm Hg) and a number of antiglaucoma medications (3.2±1.2) decreased significantly (P<0.0001 for both) to 9.8±3.3 mm Hg and 1.3±1.3, respectively, at the final visit (mean follow-up, 23 mo). The success rates of IOP control (6 to 21 mm Hg and >20% reduction irrespective of medication use) were 82.5% and 79.0%, respectively, at postoperative years 1 and 2. The most common postoperative complications were macular edema (n=9, 17%), choroidal detachment (n=8, 15%), vitreous hemorrhage (n=7, 13%), and hyphema (n=7, 13%). The most common postoperative intervention was tubal repositioning/reopening (n=6, 12%). Compared with preoperative values, the visual acuity, anterior chamber flare, mean deviation, corneal endothelial cell density remained unchanged postoperatively.

Conclusion: Choice of pars plana AGV tube insertion with simultaneous vitrectomy is reasonable to achieve IOP reduction and minimize vision-threatening complication in glaucomatous eyes with a damaged iris-lens diaphragm.