Influence of Age on Ocular Wavefront Aberration Changes With Accommodation

Abstract

To perform a quantitative analysis of high order wavefront aberrations of the entire optical system of the eye that accompanies accommodation demands in the healthy and emmetropic eye. Fifty-six healthy emmetropic eyes of 30 patients were separated into three groups according to age: group 1, 20 to 29 years; group 2, 30 to 39 years; and group 3, 40 to 49 years. Using iTrace ray-tracing technology, pupil diameter, objective refraction, and wavefront aberrations at accommodation demands of 0 to 4.00 diopters (D) in five 1.00-D increments were determined. In analyzing higher order aberrations in the central 4-mm diameter zone of the pupil, Zernike polynomials were used to study the changes associated with accommodation in the magnitude of total higher order aberrations, third order aberrations (coma-like aberrations), fourth order aberrations (spherical-like aberrations), and the spherical aberration component (C4(0)) of the fourth order aberrations. Pupil diameter decreased significantly (P < .05) with accommodation demand in each group. Total higher order aberrations in group 1 increased significantly (P < .05). No significant change was seen in third order aberrations in any group, but fourth order aberrations increased significantly (P < .05) in group 1. Spherical aberration (C4(0)) showed phase shifts from positive to negative in all groups, but the shift in group 3 was minimal, remaining positive even for a 4.00-D accommodation demand. Among higher order aberrations accompanying accommodation demands, spherical aberration (C4(0)) in particular showed characteristic changes; however, these changes showed age-related disparities. The changes were probably due to the effects of reduction in accommodation resulting from age-related changes in the crystalline lens.