Intermediate-Term Outcomes and Complications of Ahmed Glaucoma Valve in Type 1 Keratoprostheses

To evaluate intermediate-term outcomes and complications associated with Ahmed glaucoma valve (AGV) implantation in eyes with type 1 keratoprosthesis (KPro).

We retrospectively reviewed records of 43 eyes of 43 Indian patients with type 1 KPro and AGV from 2009 to 2021 with a minimum of 6-months of follow-up. Five eyes that had AGV before KPro were excluded, leaving 38 eyes for analysis. Primary outcome measure was postoperative complications. Secondary outcome measure was stability of glaucoma, assessed by Humphrey visual fields, intraocular pressure, and best-corrected visual acuity (BCVA). Sight-threatening complications, implant removal, or repeat glaucoma surgery was considered failure.

Median age (interquartile range) at AGV implantation was 36.5 (23-49) years, with median post-AGV follow-up of 30.5 (6.5-53) months. Preoperative logarithm of minimal angle of resolution median BCVA was 0.6 (0.4-1). Post-AGV, median intraocular pressure as measured by scleral Schiotz reduced significantly from 30.4 (20.6-30.4) to 13.5(12.2-14.8) mm Hg ( P < 0.0001), and the mean number of antiglaucoma medications significantly decreased from 3.4 to 1.7 ( P < 0.0001). Mean BCVA ( P = 0.24) remained stable. Humphrey visual fields mean deviation progressed from -13.5 dB (-25, -9) to -26 dB (-30, -13) at final follow-up ( P = 0.05) and progression occurred in 10 eyes. Seven eyes (18.4%) had postoperative complications needing surgical intervention, including tube block [5 eyes (13.1%)] and tube exposure [2 eyes (5%)]. One failed AGV needed additional glaucoma surgery after 8 years. None had implant extrusion/explanation or endophthalmitis.

Ahmed glaucoma valve implantation offered promising results in managing glaucoma in eyes with type 1 KPro, particularly in relatively young Indian population. However, close monitoring for tube-related complications and glaucoma progression is warranted.