Excimer Laser-Assisted Lamellar Keratoplasty and the Corneal Endothelium

Abstract PURPOSE: To evaluate endothelial changes after excimer laser-assisted lamellar keratoplasty. DESIGN: Retrospective, interventional case series. METHODS: Seven eyes of 7 keratoconus patients were evaluated for 1 year after pachymetry-guided lamellar keratoplasty, performed using the iRES Laser (Ligi Tecnologie Medicali S.p.A.), with the Corneal Lamellar Ablation for Transplantation software (Ligi Tecnologie Medicali S.p.A.) procedure. Both anterior segment optical coherence tomography (Visante OCT; Carl Zeiss Meditec, Inc) and in vivo confocal microscopy (Corneal Confocal Microscope CS4; NIDEK Technologies) images were collected. RESULTS: Changes in morphologic features were investigated and the endothelium was assessed quantitatively in all 7 patients. In 6 eyes, we measured a mean residual bed thickness of 151.3 +/- 5.46 microm, and a mean endothelial cell density loss of 5.38% at 1 year after surgery, as compared with preoperative values. The mean percentage hexagonality change was 15.67%, and the mean coefficient of variation change was -21.11%. In 1 eye, a residual bed thickness of 72 microm was found and endothelial loss after 1 year was 72.26%; assessment of the coefficient of variation and percentage hexagonality by manual Confoscan4 software (NIDEK Technologies) was not practicable in this case. CONCLUSIONS: Our results showed that the Corneal Lamellar Ablation for Transplantation procedure induced mild changes to the endothelium in corneas with a mean residual bed thickness of 151.3 +/- 5.46 microm, but serious damage in one eye with a residual bed thickness of 72 microm