Ablation profiles for wavefront-guided correction of myopia and primary spherical aberration

Abstract

Purpose: To calculate ablation profiles for wavefront-guided correction of ametropia and primary spherical aberration. Setting: Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. Methods: The primary spherical aberrations of the ocular surfaces of an aspheric eye model were calculated before and after simulated ablations for correction of myopia ranging from 0 to 10 diopters. The corneal asphericity to correct primary spherical aberration and the corresponding ablation profiles were also calculated. Results: The corneal asphericity factor that produces zero primary spherical aberration ranges from -0.45 to -0.47. The calculated ablation profiles are parabolic in first approximation, and the ablation depth varies linearly with the amount of correction. To control residual primary spherical aberration with a tolerance of one-quarter wavelength, the precision of the ablation must range from 0.2 to 0.3 μm. Conclusions: Ocular aberrometry and corneal topography can be used to calculate ablations for the correction of ametropia and primary spherical aberration. Precise control of postoperative spherical aberration appears to be feasible in theory.