Ahmed ClearPath vs. Baerveldt Glaucoma Implant: A Retrospective Noninferiority Comparative Study

Abstract

To compare the efficacy and safety of two non-valved glaucoma drainage devices (GDDs): Ahmed ClearPath (ACP) vs. Baerveldt glaucoma implant (BGI). Single-center, retrospective, comparative study. Consecutive patients who underwent ACP or BGI surgery for glaucoma (250 mm2 or 350 mm2 models), and had ≥6 months of follow-up and no prior GDD implantation. Chart review of ACP or BGI surgery in patients with glaucoma at Wills Eye Hospital (2020-2023). The primary outcome measure was surgical failure at the end of follow-up, defined as intraocular pressure (IOP) >21 or <6 mmHg at 2 consecutive visits, progression to no light perception (NLP) vision, glaucoma reoperation, or implant removal. Secondary outcome measures included the rate of postoperative complications and changes in best corrected visual acuity (BCVA), IOP, and glaucoma medications. A total of 128 eyes of 113 patients (63 ACP, 65 BGI) with similar baseline characteristics and a mean follow-up duration of 19.6±10.8 (median 20.5) months were included. Surgical failure occurred in 12 eyes (9.4%) with no significant difference between ACP and BGI eyes (9.5% vs. 9.2%, respectively; P=0.810). Reasons for failure included IOP >21 mmHg (3/12, 25.0%), glaucoma reoperation (5/12, 41.7%), and tube removal (4/12, 33.3%). No eyes progressed to NLP vision. Kaplan-Meier survival analysis showed similar cumulative rate of surgical failure in both groups (P=0.871). Both groups achieved significant IOP and medication reduction compared to their baseline. Final IOP, BCVA, and complication rate was similar in both groups, but medication number was significantly lower in the ACP group (P=0.012). Both the 250 mm2 and 350 mm2 models had similar outcomes, but diplopia was significantly associated with the 350 mm2 model of either implant (P=0.012). Univariate logistic regression analysis did not identify either tube type or plate size as predictors of surgical failure. To our knowledge, this is the first study to compare the recently approved ACP vs. the BGI. Both implants had similar surgical failure and complication rate. Final IOP was similar in both groups, but ACP achieved lower medication number. Diplopia was significantly associated with the use of 350 mm2 model of either implant. Neither tube type nor plate size were significant predictors of surgical failure.