Risk factors for various causes of failure in initial corneal grafts

Objective: To determine the risk factors for specific causes of initial corneal graft failure. Methods: This study analyzed corneal graft survival rates in a longitudinal noncomparative case series of 3992 consecutive penetrating keratoplasties performed at a single large referral center. Regrafts (n = 352) were excluded from the analysis of risk factors for initial graft failure. Data were collected retrospectively from August 1, 1982, through December 31, 1986, and prospectively from January 1, 1987, through August 31, 1996. Patients were examined preoperatively, at 1, 3, 6, 9, 12, 18, and 24 months posttransplantation, and annually thereafter. Potential risk factors were evaluated individually by Kaplan-Meier survival analysis. Cox proportional hazards regression modeling was then used to investigate the impact of each independent variable, adjusted for the confounding influence of the other independent variables. Results: The use of topical glaucoma medications was a significant risk factor for corneal graft failure by 3 major causes: rejection, endothelial decompensation without a documented immunologic reaction, and ocular surface disease. Deep stromal vascularization was an independent risk factor for rejection failure. Diabetes mellitus, peripheral anterior synechiae, recipient race, and small trephination size were significant risk factors for endothelial failure. Conclusion: Independent risk factors differentially impact specific causes of corneal graft failure.