Penetrating keratoplasty in Asian eyes: the Singapore Corneal Transplant Study.

PURPOSE: The Singapore Corneal Transplant Study (SCTS) is a 16-year prospective study of 2100 consecutive corneal transplants performed between January 1991 and November 2006 in patients from Southeast Asia at a single tertiary center. The indications, complications, long-term survival rates, and risk factors for graft failure of penetrating keratoplasty (PK) performed in Asian eyes are reported. DESIGN: Prospective cohort study. PARTICIPANTS: Of the 2100 corneal transplants, 1130 consecutive PKs were performed from January 1991 to December 2003. One graft per patient was selected, leaving 901 grafts for analysis. METHODS: Data were obtained from the Singapore Eye Bank's SCTS database. Cases were classified into optical, therapeutic, and tectonic indications and 9 corneal disease groups. Twenty-four demographic, preoperative, intraoperative, and donor risk factors were subjected to Kaplan-Meier survival analysis, univariate analysis, and multivariate analysis by Cox proportional hazards regression modeling. MAIN OUTCOME MEASURE: Graft failure, defined as the irreversible loss of optical clarity. RESULTS: Study patients were Asian, comprising Chinese (72.7%), Indian (11.54%), and Malay (11.1%) ethnicities (mean age, 56.65 years). The mean follow-up period was 36.8+/-35.5 months. Indications for surgery were optical (87.0%), therapeutic (8.1%), and tectonic (4.88%). Main diagnoses were pseudophakic/aphakic bullous keratopathy (23.4%), postinfectious scarring (12.9%), regrafts (12.4%), keratoconus (9.7%), and posttraumatic scarring (7.3%). Kaplan-Meier survival rates for optical grafts were 86.6%, 72.0%, 63.7%, and 52.0% at 1, 3, 5, and 10 years, respectively; survival rates for therapeutic grafts were 78.4%, 58.3%, and 37.3% at 1, 3, and 5 years, and those for tectonic grafts were 68.3% and 41.7% at 1 and 3 years. Endothelial rejection and late endothelial decompensation accounted for 50.51% of failures. Multivariate analysis revealed 9 predictors for graft failure: recipient gender, age, graft size, graft endothelial status, primary corneal disease, glaucoma, inflammation, perforation, and corneal vascularization. CONCLUSIONS: The long-term outcome for optical indications in Asian eyes follows a trend in endothelium-related attrition similar to that seen in the West. Tectonic and therapeutic keratoplasty for corneal infections and perforation, however, constitute a significant proportion of corneal transplantation performed in Asia and carry a graver prognosis in terms of graft survival.

Therapeutic keratoplasty for advanced suppurative keratitis.

PURPOSE: To determine indications, therapeutic success, and corneal transplantation techniques for advanced medically uncontrolled infectious keratitis. DESIGN: Retrospective, interventional case series. METHODS: A review of 92 consecutive patients (1991 to 2002) who underwent therapeutic keratoplasty for acute infectious keratitis performed at Singapore National Eye Centre. Causative organism(s) were identified and outcomes were evaluated in terms of infectious cure (therapeutic success), graft clarity, and visual acuity. RESULTS: Pseudomonas aeruginosa (58.7%) and Fusarium species (32.3%) were the predominant organisms for bacterial and fungal keratitis, respectively. Keratoplasty types included penetrating keratoplasty (PK; n = 80) and lamellar keratoplasty (n = 12). Mean graft diameter was 9.5 mm (range, 5.5 to 14 mm). Seventy-four patients (80.4%) achieved therapeutic success after one keratoplasty procedure, three patients were cured after a second keratoplasty. Life-table survival analysis computed the one-year therapeutic survival for bacterial and fungal keratitis as 76.6% and 72.4%, respectively (P = .76). The Kaplan-Meier one-year survival rate for PK optical clarity was 72%. Twenty-two patients underwent repeat keratoplasty for various reasons (optical, n = 8; recurrent primary infection, n = 7; perforation or subsequent new infections, n = 7). Of the 15 patients for whom therapy failed, 11 had fungal keratitis. Infection recurrence time was four days to one year. Most recurrences (n = 11) appeared within six weeks after surgery. CONCLUSIONS: Therapeutic keratoplasty may treat severe, refractory infectious keratitis effectively. High cure rates are achievable, although infection recurrence despite prolonged treatment remains a significant problem in fungal keratitis.