Epidemiology and risk factors for corneal graft rejection

Objective. The aim of this study was to evaluate the frequency and main risk factors for corneal graft rejection. Patients and Methods. This retrospective study included 285 eyes in 256 patients who underwent a penetrating keratoplasty (KPT) from January 1.995 to December 2004. The minimum follow-up was 12 months to evaluate graft evolution. Except for complications, the follow-up was weekly, then monthly for 6 months, and ultimately quarterly during the first year. Thereafter the follow-up was performed semi-annually. Patients were informed about the functional signs for which they have to urgently consult. Results. Immunologic rejection of the corneal graft occurred in 128 KPT in 112 patients (rejection frequency = 41%). The identified main risk factors were new vascularization of the recipient cornea over 2 or more quadrants, corneal opacity due to an infectious origin, posttraumatic corneal opacity or congenital glaucoma, graft diameter >8 mm, and therapeutic KPT. Conclusions. Rejection of the corneal graft is the primary cause of KPT failure. One out of 2 graft failures was due to rejection. Two criteria are unanimously recognized as risk factors for rejection: neovascularization of recipient cornea and antecedents of corneal rejection. The rejection must be treated early to not endanger graft success, which imposes a close follow-up for grafted patients.