The corneal-ablation rate, the beam-intensity distribution, and the initial and the desired corneal topographies are used to calculate a spatial distribution map of laser pulses. The optimal values of the parameters are determined with a computer model, for a system that produces 213-nm radiation with a Gaussian beam-intensity distribution and a peak radiant exposure of 400 mJ/cm2. The model shows that with a beam diameter of 0.5 mm, an overlap of 80%, and a 5-mm treatment zone, the roughness is less than 6% of the central ablation depth, the refractive error after correction is less than 0.1 D for corrections of myopia of 1, 3, and 6 D and less than 0.4 D for a correction of myopia of 10 D, and the number of pulses per diopter of correction is 2500 when the beam-intensity distribution is Gaussian and 580 when it is flat.
© 1995 Optical Society of America
Original Manuscript: August 29, 1994
Revised Manuscript: February 27, 1995
Published: July 20, 1995
Fabrice Manns, Jin-Hui Shen, Per Söderberg, Takaaki Matsui, and Jean-Marie Parel, "Development of an algorithm for corneal reshaping with a scanning laser beam," Appl. Opt. 34, 4600-4608 (1995)