Abstract
Purpose:
Aim of the study was an excimer based smoothing and thinning of the posterior lamella of corneal transplant before implantation in posterior endothelial Keratoplasty (DSAEK).<br />
Methods:
8 human corneas were prepared with microkeratome (Moria, 300 µm cutter), followed by controlled excimer-laser (Esiris, Schwind) photoablation of the corneal lamella. Different ablation profiles (myopic, hyperopic and PTK) and laser parameter (time, depth) were analysed. Simultane online pachymetry (Heidelberg Engineering) was used to measure the transplants thickness during the ablation process. Endothelcell density and the termic effect on the graft tissue were evaluated.<br />
Results:
Myopic Ablation and PTK resulted in a smoothening of the whole corneal lamella. The hyperopic profile lead to a peripheral ablation without affecting the central (optic) zone. Mean ablation depth was 87 µm±74 µm and the mean ablation time was 106.8 s ±84 s. Before and after ablation the endothelcell density was 1320±487 cells/mm2 and 1338±538 cells/mm2 respectively. There was no significant change in endothelcell density. Histologically all corneal lamellas showed a smoothend surface. There was no corneal perforation of the grafts during laser treatments.<br />
Conclusions:
Excimer based photoablation before posterior endothelial Keratoplasty is a new method to thin out and to smooth superficial irregularities of the corneal lamella. Time and depth of ablation had no influence on endothelcell density. This technique is safe for the the endothelium and the transplant.<br />