A method for estimating the wavefront aberrations with missing spot data in a hartmann-shack aberrometer

Abstract

This paper reports a method of wavefront sensing based on Hartmann- Shack (HS) centroid displacements and predicts the number of HS spots that can be successfully deleted without hampering the prediction of the defocus of the computed wavefront, described via Zernike polynomials. The deletion of the HS spots was randomized. The experiment was performed on real data acquired through a custom made aberrometer tested on a model eye with various axial lengths to simulate refractive errors (defocus) between ~±1.50D. Estimates of defocus were made from each of 1000 runs at each axial length. The paper presents the standard deviation of error and mean error for 1000 trials. The results indicate that as high as 50 % of the HS spots can be deleted without affecting the estimation of spherical defocus, within typical clinically acceptable limits of ±0:25D.