Risk Factors for Earlier Reexposure of Glaucoma Drainage Devices

The purpose of this study was to investigate factors associated with a second exposure of a glaucoma drainage device (GDD) following repair of an initial GDD exposure.

This IRB-approved retrospective cohort study examined the incidence of a second exposure of a GDD following initial repair for exposure. Logistic regression was performed to assess the relationship between demographic and clinical characteristics and a second exposure of the GDD. Kaplan-Meier survival curves were plotted and Cox regression was performed to examine factors impacting the time to a second GDD exposure.

Ninety-four eyes of subjects that underwent initial revision for GDD exposure were reviewed. Approximately 44% (N=41/94) of subjects underwent surgical revision for a second exposure. Factors associated with reexposure in multivariate logistic regression included caucasian race (odds ratio, 2.99; P=0.02) and use of a nonscleral patch graft (odds ratio, 2.93; P=0.019). Time from revision of the initial exposure to reexposure was significantly shorter for those with a nonscleral patch graft (hazard ratio, 2.23; P=0.01) and caucasian race (hazard ratio, 2.08; P=0.04).

Caucasian race and use of a nonscleral patch graft during revision surgery was associated with a higher risk of experiencing a sooner reexposure of the GDD following revision of an initial exposure. Future studies should examine whether particular graft materials increase the risk of GDD reexposure.