Development of Selective Lamellar Keratoplasty within an Asian Corneal Transplant Program: The Singapore Corneal Transplant Study (An American Ophthalmological Society Thesis).

PURPOSE To evaluate outcomes of anterior lamellar keratoplasty (ALK) and endothelial keratoplasty (EK) within the Singapore Corneal Transplant Study (SCTS), with the hypothesis that both ALK and EK are able to provide equivalent or improved clinical outcomes, compared to penetrating keratoplasty (PK), and to determine changing trends globally with other international databases. METHODS Clinical data on all transplants performed was derived from our SCTS database, a prospective national keratoplasty registry, and clinical outcomes (graft survival, endothelial cell loss, complications, visual acuity) were compared between PK, ALK, and EK. Global trends on indications and forms of keratoplasty performed in 2011/2012 were obtained from national keratoplasty or eye banking registries, corneal/ophthalmological societies, national eye banks, and national ophthalmic institutions. RESULTS Global rates of EK surgery vary widely, from 52% (Sweden) to 0% (South Africa), with higher adoption by industrialized countries. ALK adoption rates similarly vary from 28.7% (China) to 1.0% (Philippines). SCTS data show high adoption rates in Singapore: EK 44% and ALK 28%. Our surgical modifications to big-bubble deep anterior lamellar keratoplasty (DALK) surgery resulted in visual outcomes matching PK, and a low conversion to PK of 2.1%, whereas our evolving approaches to donor insertion in Descemet's stripping automated endothelial keratoplasty (DSAEK) show significant reduction in 1-year postoperative endothelial cell loss rates from 60% (folding), to 22% to 30% (Sheets Glide), to 15% (EndoGlide inserter). CONCLUSION Improvements in various forms of ALK and EK surgery can lead to better visual outcomes, longer graft survival, and reduced complications, as compared to PK. Global trends suggest adoption of these procedures at different rates.