A SCANNING AND ROTATING SLIT ARF EXCIMER-LASER DELIVERY SYSTEM FOR REFRACTIVE SURGERY

PURPOSE: This study was designed to investigate the quality of a scann ing and rotating slit delivery system of an ArF excimer laser (Nidek E C 5000). METHODS: The ablation patterns on polymethylmethacrylate (PMM A) wafers were examined by scanning electron microscopy. The influence of inhomogeneities in the beam profile was simulated on a computer an d compared with a conventional large-area ablation system. The impairm ent of the ablation rate by radiation absorption of the ablation plume was measured as a function of the repetition rate and the application of a fixation ring. RESULTS: The scanning and rotating slit delivery system is tolerant of small-beam non-homogeneities. The ablation rate is sensitive to the dynamics of the ablation plume. CONCLUSIONS: Altho ugh the operating procedure takes less time with a large-area ablation system, a scanning and rotating delivery system has the advantage of reliable and homogeneous removal of corneal tissue.