Effect of a WaveLight Prototype Femtosecond Laser on Corneal Tissue

Abstract

Purpose: : Modern corneal laser surgery for the correction of refractive errors require a precise,reliable and reproducible creation of corneal flaps. Femtosecond Laser with ultra-short laser pulses with pulse durations of a few 100 femtoseconds allows nonthermal cuts of ocular tissue. Aim of this study was to look at the cut quality and the corneal lateral damage of a new femtosecond laserSetting: Klinik und Poliklinik fuer Augenheilkunde, Klinikum rechts der Isar, technische Univeristaet Muenchen, Munich, Germany.

Methods: : 30 porcine eyes were obtained from the butcher and 5 human eyes, not suitable for transplantation, where obtained from the eye bank. A WaveLight prototype femtosecond laser was used for all Flap cuts. Different flap depths (100µm, 200µm 300µm, 700µm and 800µm for porcine and 150µm and 400µm for human eyes) have been cut. The surface of the cornea, the structure and ultra structure of the corneal cells and stroma were evaluated thoroughly using light microscopy (PAS and Picrosirius red staining), transmission electron microscopy (TEM), and scanning laser electron microscopy (SEM).

Results: : In all eyes the flap could be lifted very easily and the flap appeared very smooth and structural and ultra structural evaluation with light and transmission electron microscopy of 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 fibers showed no alteration. Scanning laser electron microscopy revealed in cases smooth surfaces and sidecuts.

Keywords: laser • refractive surgery: LASIK • cornea: stroma and keratocytes