Efficacy of the Ahmed S2 Glaucoma Valve Compared with the Baerveldt 250-mm2 Glaucoma Implant
Presented in part at: Association for Research in Vision and Ophthalmology annual meeting, May 2006, Fort Lauderdale, Florida.
Received 30 May 2007; received in revised form 18 October 2007; accepted 22 October 2007. published online 03 January 2008.
Objective
To compare the efficacy of the Ahmed S2 Glaucoma Valve with the Baerveldt 250-mm2 Glaucoma Implant in the treatment of adult glaucoma.
Design
Comparative case series.
Participants
Fifty-nine eyes of 59 patients who received the Ahmed S2 Glaucoma Valve and 133 eyes of 133 patients who received the Baerveldt 250-mm2 Glaucoma Implant by the Indiana University Glaucoma Service from 1996 to 2003.
Methods
Eyes that had previous drainage implant procedures were excluded from both groups. If both eyes of a single patient received an implant, the second eye to undergo implantation was excluded from the study.
Main Outcome Measures
Kaplan–Meier survival with success defined as intraocular pressure (IOP) > 5 mmHg and < 22 mmHg and at least 20% reduction from preoperative IOP (with or without antiglaucoma medications) and without loss of light perception. Secondary outcome measures included intraocular pressure, visual acuity, number of glaucoma medications, and surgical complications.
Results
The 2 groups were similar with regards to age, gender, race, neovascular glaucoma diagnosis, number of prior ocular surgeries, preoperative IOP, and number of preoperative glaucoma medications. Mean durations of follow-up were 20.0 months for Ahmed eyes and 22.9 months for Baerveldt eyes. Cumulative successes in the Ahmed group were 0.73 at 1 year and 0.62 at 2 years, whereas cumulative successes in the Baerveldt group were 0.92 at 1 year and 0.85 at 2 years (Kaplan–Meier survival functions: P = 0.03, log rank test). Male gender, African descent, neovascular glaucoma, and Ahmed implantation were found to be significant predictors of failure. At last follow-up visit, eyes in the Ahmed group had a significantly higher mean IOP (19.8±9.5 vs. 15.8±7.9 mmHg, P = 0.003, t test) and more antiglaucoma medications (1.4±1.2 vs. 0.9±1.1 medications, P = 0.008, Mann–Whitney test) than eyes in the Baerveldt group. Two methods for avoiding hypotony after Baerveldt 250-mm2 implantation had similar outcomes.
Conclusions
Our study suggests that the Ahmed S2 Glaucoma Valve may be less effective at lowering IOP than the Baerveldt 250-mm2 Glaucoma Implant.
Available online: December 27, 2007.
Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana.
Correspondence to Darrell WuDunn, MD, PhD, Indiana University Department of Ophthalmology, 702 Rotary Circle, Indianapolis IN 46202.
Manuscript no. 2007-723.
Financial support: Research to Prevent Blindness, Inc., New York, New York (unrestricted departmental grant).
Dr WuDunn has received speaker's honoraria from Pfizer, which used to market the Baerveldt implant. Dr Cantor has received speaker's honoraria from Advanced Medical Optics, which presently markets the Baerveldt implant. No other author has any conflict of interest.
ABSTRACT