Schnittqualität eines neuen Femtosekundenlasers

Objective: The aim of this study was to evaluate the cut quality and the cellular damage when using a new 200 kHz femtosecond laser. Methods: 20 porcine eyes and 3 human eyes, not suitable for transplantation, were used for this study. The WaveLight UltraFlap femtosecond laser was used for flap creation. The surface of the cornea, the structure and ultrastructure of the corneal cells and stroma were evaluated thoroughly using light microscopy (HE-, PAS- and Picrosirius red staining), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Results: In all eyes, the flap could be lifted very easily and the flap appeared very smooth. Structural and ultrastructural evaluation with light and transmission electron microscopy on epithelium and endothelium showed no side effects of the laser application. The area around the flap cut was minimally affected and the keratocytes and collagen fibres showed minimal alteration due to laser treatment. Scanning electron microscopy revealed in all cases smooth surfaces and precise sidecuts. Conclusions: Precise corneal flaps can easily be created with this new femtosecond laser. At the same time, no structural and thermal side effects on corneal epithelium, stroma and endothelium appeared. Hence with this new femtosecond laser corneal flaps could be created easily without noteworthy side effects.