Corneal contribution to the wavefront aberration of the eye.

摘要

Introduction. The wavefront aberration function is one of the most informative descriptors of optical performance, and new techniques have recently been developed to measure this function in living human eyes. Corneal refractive surgery is creating a population of patients with abnormally large aberrations, and the key to improving optical results is a better understanding of the eye's aberrations. The purpose of this research was to determine the corneal contribution to the aberrations of three normal human eyes. Methods. An EyeSys computerized videokeratoscope was used to measure corneal topography, and the corneal wavefront aberration was computed. A Shack-Hartmann wavefront sensor was used to measure the ocular wavefront aberration. Corneal and ocular aberration data were fitted to Zernike polynomials, and corresponding coefficients were compared to determine the relationship between corneal, internal and total ocular aberrations. Results. Contrary to what other researchers had hypothesized, I did not find a general pattern of aberration balancing between the cornea and internal elements of the eye. Instead, within a range of normal values, the relationship between the optical elements varied with each eye. Conclusion. We cannot know the relationship between the corneal and ocular wave aberration functions without individually measuring these functions for each eye. Recent improvements in corneal topographers have made it clinically feasible to measure the corneal wavefront aberration function. Better correction of ocular aberrations will require new clinical instruments that can measure the wavefront aberration of the whole eye as well.