Risk factors for corneal graft failure and rejection in penetrating keratoplasty

Objective: To evaluate risk factors for graft failure and allograft rejection after penetrating keratoplasty （PK）. Methods: Clinical data of PKs on 224 eyes （212 patients） from 1993 through 2003 were studied retrospectively. The graft survival rate and rejection-free survival rate over 10 years were estimated with Kaplan-Meir’s life table method, and differences between levels of each factor were compared with log-rank test. Cox regression was also performed to further assess the impact of related clinical factors on the prognosis of the corneal graft. Results: The overall rates of graft survival and rejection-free graft survival in 10 years after PK were 81.4% and 78.2%, respectively. Higher relative risk of graft failure was associated with corneal vascularization, regraft, aphakia or pseudophakia, presence of anterior or posterior synechia, long operation time （≥90min） and older recipient age（≥60 years）. Higher relative risk of rejection was associated with corneal revascularization and long operation time. Cox regression analysis showed corneal vascularization（RR=2.46,P=0.04）,regraft（RR=5.67,P＜0.01）, aphakia（RR=（3.64,P）＜0.05）, or pseudophakia（RR=6.83,P＜0.01）, presence of anterior（RR=2.76,P=0.05） or posterior synechia （RR=3.12,P=0.05） were independent risk factors for corneal graft failure. Conclusion: The risk factors for graft failure after PK were corneal vascularization, regraft, aphakia or pseudophakia, presence of anterior or posterior synechia. The risk factors after PK for allograft rejection were corneal vascularization and long operation time.