Abstract
Abstract: :
Purpose: The human eye is subject to about 2 Dioptres of longitudinal chromatic aberration (LCA) across the visible spectrum. This change in focus is caused by dispersion in the ocular media, which could in turn cause similarly scaled changes in other aberrations. However, the literature shows that the dispersions of the lens and cornea differ, and also that dispersion changes across the lens. This suggests that higher order wave aberrations may change in more complex ways with wavelength. The current work investigates these possibilities. Methods: Wave aberrations were measured for six subjects at eight different wavelengths (430 to 670 nm) using a spatially resolved refractometer (7mm pupil). Data from 3 runs at each wavelength were fit with Zernike polynomials through the seventh order. LCA was estimated by the change in the second–order defocus term. Results: For each subject, LCA magnitude was consistent with previous results. Linear correlations were performed for each Zernike term vs. wavelength. 5 of the 6 subjects showed significant correlations for at least one 3rd or 4th order Zernike coefficient. One subject showed a robust and reproducible change in spherical aberration. Conclusions: Reproducible changes in higher order aberrations with wavelength were measured in some subjects. These changes could arise from differential interactions between lenticular and corneal aberrations across the spectrum. Though small, these changes may play a role in polychromatic image quality.
Keywords: optical properties • color vision • refraction