Corneal Graft Rejection; Prevalence and Risk Factors

Background: Rejection is the most common cause of late corneal graft failure. The purpose of this study is determining the prevalence, and defining the role of those factors which may affect the risk for rejection. Methods: The study was conducted on all patients who had penetrating keratoplasty without immunosuppressive therapy with at least 1 year follow up. Demographic status, cause of graft, and types of rejections were detemined. Contribution to graft rejection, persistence of transparency, and rate of failure due to rejection were considered for each factor. Statistical analysis was performed by multivariate regression and ANOVA tests. Results: Two hundred ninety five penetrating keratoplasties were performed on 286 patients (61% male, 39% female). Mean age at keratoplasty was 38 ± 20 years. Mean follow-up period was 20 ± 10 months. Graft rejection occurred at 7.3 ± 6 months (20 days to 39 months) in 31.8% of cases. The most common type of rejection was endothelial (20.7%). Contributing factors were extent of corneal vascularization, regrafting, anterior synechiae, irritating sutures, active inflammation at the time of surgery, additional anterior segment surgery, history of trauma, uncontrolled glaucoma, history of prior graft rejection, recurrence of herpes infection on graft, and eccentric graft (P<0.05). Patients’ age, size of donor cornea, and bilateral transplantation were not significant. Conclusions: The extent and severity of corneal vascularization, anterior synechiae, irritating sutures, active inflammation, regrafting, additional surgery, trauma, uncontrolled intra-ocular pressure, history of graft rejection,