Corneal Edema and Keratoplasty: Risk Factors in Eyes With Previous Glaucoma Drainage Devices

Abstract

Purpose: To assess risk factors contributing to corneal decompensation following glaucoma drainage device (GDD) implantation.

Design: Retrospective case control study.

Methods: Records of 1610 eyes that underwent GDD implantation between June 1, 2009, and April 1, 2020, at the Johns Hopkins Wilmer Eye Institute were reviewed. Seventy-nine eyes (5%) developed corneal decompensation, of which 46 underwent keratoplasty. These 79 cases were matched with 220 controls. Cox proportional hazard models with robust standard error estimates to account for clustering at the matched-pair level were used to assess risk factors for corneal decompensation. Kaplan-Meier survival analysis analyzed time to corneal decompensation.

Results: The mean (SD) age of cases and controls was 68 (12.3) and 60.5 (15.9) years, respectively. The mean time from GDD implantation to corneal decompensation was 32 months, and the cumulative probability of developing decompensation at 3, 6, and 9 years was 4.7%, 9.2%, and 14.8%, respectively. Final visual outcomes in cases were worse, with a final mean ± SD visual acuity (logMAR) of 1.96±1.25 relative to a mean±SD visual acuity of 1.11±1.36 in controls (P < .001). In the multivariable model, significant risk factors for corneal decompensation were increased age (adjusted hazard ratio [AHR] 1.39, 95% CI 1.18, 1.63; P ≤ .001), history of Fuchs dystrophy or iridocorneal endothelial syndrome (AHR 9.18, 95% CI 5.35, 15.74; P ≤ .001), and postoperative complications such as hypotony (AHR 3.25, 95% CI 1.85, 5.72; P ≤ .001) and tube-cornea touch (AHR 6.37, 95% CI 3.77, 10.75; P ≤ .001).

Conclusions: The risk of postoperative corneal decompensation is persistent over time. Patients receiving GDDs, particularly those with advanced age, preexisting corneal pathology, and postoperative complications, should be counseled regarding their increased risk for corneal decompensation.

Keywords: corneal decompensation; corneal edema; glaucoma drainage device; keratoplasty; risk factors; tube shunt.

Figure 1.

Kaplan-Meier survival analysis curve showing proportion of eyes without corneal edema following glaucoma drainage device implantation in a 1610 eye cohort. The proportion of eyes without corneal edema at 3 years, 6 years, and 9 years post-glaucoma drainage device implantation were 95.3%, 90.8%, and 85.2%, respectively.

Figure 2.

Box and whisker plot showing visual outcomes in eyes with and without corneal decompensation or keratoplasty post-glaucoma drainage device implantation. The center line denotes the median visual acuity value (50^th percentile), while the box borders denote the interquartile range (25^th and 75^th percentiles). The whiskers represent the 5^th and 95^th percentiles, and dots denote individual outlier values.