Abstract
Abstract: :
Aim : To evaluate the potential preoperative risk factors for graft failure for penetrating keratoplasties in an Asian population . Method : A retrospective analysis of 857 consecutive penetrating keratoplasties (PKPs) performed at the Singapore National Eye Centre, a tertiary institute during 1991 to 2001 was done. All corneal grafts other than PKPs were excluded. The comprehensive database, comprising of Preoperative, Operative and Postoperative annual followup data captured with specifically designed forms, was reviewed and updated from hospital case records for followup until October 2003. Average follow–up time was 35.37 months, ranging from one day to 149 months. Results : Recipient age ranged from 1 to 96 with a mean of 56 yrs. There were 512 males and 345 females with a predominant Chinese distribution (619) followed by Malays (100) and Indians (96). Main diagnostic indications were pseudophakic (14.4%) aphakic bullous keratopathy (7.9%) keratoconus (8.9%), acute infectious keratitis (7%) and post–infectious corneal scar (12.1%). The total number of graft failures was 308. Overall Kaplan–Meier survival rates for 1,3,5 and 10 years were 83%, 66%, 55% and 41% respectively. Grafts for Optical indications had the highest 1yr and 5yr survival rates (86%, 57%) compared to tectonic and therapeutic indications. Keratoconus had the highest 1 and 3yr survival rates of 100% followed by Post infectious scar(95%,84%),Fuchs endothelial dystrophy(90%,82%),Pseudophakic bullous keratopathy(87%,50%) while for Infective keratitis it was 63% and 52% respectively.The multivariate cox proportional hazards regression model showed key predictors of graft failure to be globe perforation(3.58,(95%CI 2.30,5.58),superficial vascularisation (1.95,(95% CI 1.51,2.51), active inflammation (1.86,(95% CI 1.37,2.51)and glaucoma (1.69,(95% CI 1.28,2.23). Conclusion : Major preoperative risk factors predicting graft failure in our Asian population are tectonic indications (due to globe perforation), corneal vascularisation, inflammation and glaucoma. The high rate of infectious keratitis leading to more tectonic and therapeutic indications for grafting also lead to lower overall graft survival rates in our Asian population.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • clinical research methodology • cornea: clinical science