Outcomes of Ahmed glaucoma valve implantation and risk factors for graft failure in eyes with Descemet's stripping endothelial keratoplasty.

Abstract

The aim of this study was to assess the efficacy of Ahmed glaucoma valve (AGV) in eyes with Descemet's stripping endothelial keratoplasty (DSEK) and glaucoma and evaluate the risk factors for failure. Retrospective interventional study included 27 eyes (27 subjects) that underwent AGV implantation following DSEK. The main outcome measure was AGV success, defined as IOP between 6 and 21mmHg with or without topical antiglaucoma medications (AGMs). Secondary outcome measure was graft survival. Graft failure was defined as corneal edema for ≥ 1month or irreversible graft opacity requiring intervention. Eighteen eyes (66.7%) had anterior chamber tube and 9 eyes (33.3%) had sulcus tube placement. Median follow-up was 1.2years (interquartile range, IQR, 0.5-2.5years). Following AGV implantation, the median IOP decreased significantly (p < 0.0001), median number of AGMs reduced significantly (p < 0.001) and median visual acuity was maintained (p = 0.76). Cumulative success probability of AGV was 75.8 ± 10.6% at 1year, and 75.8 ± 10.6% at 2years. For 24 clear grafts before AGV, estimates of success post-AGV were 100% at 1year, 77.8 ± 10% at 2years and 51.9 ± 16.4% at 3years. Postoperative tube intervention was a borderline significant risk factor for graft failure (p = 0.05) with hazards ratio of 7.2; however, tube location was not associated with failure. AGV can be considered an effective surgical option for IOP control in eyes with DSEK and glaucoma. However, high risk of long-term graft failure in these eyes needs to be considered specially those eyes needing tube intervention.