Evaluation of the Hypertensive Phase after Ahmed Glaucoma Valve Implantation in Neovascular Glaucoma

Abstract

Purpose : To evaluate the short- and intermediate-term outcomes of the Ahmed glaucoma valve (AGV) in neovascular glaucoma (NVG), comparing eyes with and without a hypertensive phase (HP).

Methods : This was a single-center retrospective case series of consecutive NVG eyes that underwent AGV implantation with ≥ 6-month follow-up. HP was defined as intraocular pressure (IOP) >21mmHg at ≥ 2 visits within the first 3 months following surgery. Reported outcomes included failure at month 6 and at the most recent visit. Failure was defined as IOP >21mmHg, progression to no light perception (NLP) vision, or glaucoma reoperations (all with IOP-lowering medications). Other secondary outcomes included IOP and number of glaucoma medications.

Results : 76 eyes of 74 patients (37 without HP and 39 with HP) with follow-up duration of 28.9±25.7 months (P=0.602) were included. Patient demographics, visual acuity (VA), number of medications, NVG etiology, and perioperative retina treatment were similar in both groups. Baseline IOP was higher in the HP group (P=0.001). At month 6, 13 HP (33.3%) eyes vs. 3 non-HP (8.1%) eyes met the failure criteria (P=0.01). However, at the most recent visit, failure was higher in the HP group; the difference did not reach statistical significance (53.8% vs 35.1%; P=0.113). Kaplan-Meier analysis showed similar cumulative failure in both groups (P=0.180) (Figure 1). Reasons for failure were similar between groups (P=0.237): high IOP in 9 (26.5%) eyes, progression to NLP in 10 (29.4%) eyes, glaucoma reoperation in 14 (41.2%) eyes, and tube removal in 1 (2.9%) eye.

With the exception of post-operative day 1, IOP during the first 6 postoperative months was significantly higher in the HP group (P<0.05 for all). At the most recent visit, IOP was similar in both groups (P=0.211) (Figure 2A), but number of medications was higher in the HP group (P=0.023) (Figure 2B). Postoperative complications were similar and infrequent in both groups.

Conclusions : HP eyes had higher preoperative IOP and more commonly failed in the first 6 months following AGV implantation in NVG compared to non-HP eyes. This study did not detect a significant difference in surgical failure at the most recent visit between the two groups, but HP eyes required a significantly higher number of medications.

This is a 2021 ARVO Annual Meeting abstract.

 

Figure 1: Kaplan-Meier curve of cumulative survival

 

Figure 2: (A) IOP changes over time and (B) Number of medications over time