Abstract
Purpose: :
Wavefront aberrations are commonly described as errors of wavefront phase or optical path length. We aimed to develop an alternative description as errors of wavefront vergence derived directly from measurements of wavefront slope.
Methods: :
We define wavefront vergence as radial wavefront slope normalized by radial distance from the pupil center. The result is a wavefront vergence map that is similar in concept to the power map in corneal topography and hence has a potential to be favored by clinicians. We use a recently invented set of orthogonal Zernike slope polynomials to systematically analyze details of the wavefront vergence map just as we might use Zernike polynomials for analyzing wavefront phase.
Results: :
Wavefront vergence maps can be used to characterize aberrations using simple statistics such as mean, variance, skewness, and kurtosis. Vergence maps can also be described by a vector of Zernike slope coefficients that are linearly related to ordinary Zernike phase coefficients. Three different methods for converting Zernike slope coefficients to sphero-cylindrical refractive error have been derived based on different methods for weighting the contribution of different points in the pupil. Significant differences between the three methods appear when higher order aberrations are present.
Keywords: aberrations • refraction