Risk factors for corneal graft failure and rejection in penetrating keratoplasty

PURPOSE: To evaluate risk factors for graft failure and allograft rejection after penetrating keratoplasty (PK). METHODS: We retrospectively studied clinical results of PKs in terms of graft survival and rejection-free graft survival rates. PKs were done on 271 eyes between 1987 and 1997. Clinical results were analyzed by Kaplan-Meier's life table method and the log-rank test. Relative risks and adjusted survival probabilities for each value of the factor were compared with the risk for a specified reference value. RESULTS: The overall rates of graft survival and rejection-free graft survival in 10 years after PK were 79.3% and 77.9%, respectively. Higher relative risk of graft failure was associated with corneal vascularization (relative risk for within one quadrant = 1.67, two quadrants = 2.37, three or more quadrants = 3.39), regraft (relative risk for one failed previously graft = 2.08, two or more failed previously graft = 2.65), aphakia (relative risk = 2.17) or pseudophakia (relative risk = 3.02), presence of anterior synechia (relative risk = 2.91), presence of posterior synechia (relative risk = 2.56), long (more than 85 minutes) operation time (relative risk = 2.20), and older (more than 50 years) recipient age (relative risk = 2.38). Higher relative risk of rejection was associated with corneal vascularization (relative risk for within one quadrant = 2.35, two quadrants = 2.03, three or more quadrants = 2.63), long (more than 85 minutes) operation time (relative risk = 1.47), and younger (less than 60 years) donor age (relative risk = 2.10). There was no association between graft failure or allograft rejection and graft size or suture technique, respectively. CONCLUSION: The risk factors for graft failure after PK were corneal vascularization, regraft, aphakia or pseudophakia, presence of anterior synechia, presence of posterior synechia, long operation time, and older recipient age. The risk factors after PK for allograft rejection were corneal vascularization, long operation time, and younger donor age.