Abstract
Purpose:
Previous studies have measured peripheral optics of the human eye with eccentric fixation using commercial devices. These devices required subjects to turn their eyes to measure peripheral aberrations. The goal of the study is to measure wavefront aberrations at peripheral retina with accommodation using a custom built peripheral wavefront sensor which does not require eccentric fixation.
Methods:
The open view peripheral wavefront sensor can rotate about the pupil center while subjects maintain their natural foveal fixation. Accommodation can be stimulated naturally without visual distraction as wavefront sensing light source is totally invisible (λ=980nm). Wavefront aberrations measured in four myopic subjects (aged from 22 to 28, refractive error: -1 .00 to -4.50D) with their natural pupils at fovea ( 0°) and peripheral retina ( 10° and 20°) with distance (0D) and near target vergence (3D and 5D). During these measurements, subjects were fixating on a high contrast free space target (i.e. Maltese cross) displayed on a micro display. Zernike polynomials up to 10th radial order were fit to the wavefront measurements for a fixed 4 mm pupil.
Results:
Subjects became more myopic in the periphery with accommodation compared to fovea (mean difference: 0.33 ± 0.54 D and 0.27 ± 0.74 D for 3D stimulus at 10° and 20° eccentricity, respectively; 1.1 ± 0.58 D and 0.83 ± 0.61 D for 5D stimulus at 10° and 20° eccentricity, respectively). Of the higher order aberrations, horizontal coma C (3, 1) had a greater change at 20° eccentricity compared to fovea (mean difference 0.03±01 µm, p=0.02) with accommodation. Accommodation caused greater changes in primary spherical aberration C(4,0) at periphery compared to fovea (mean change: -0.02±0.01 µm, -0.02±0.01 µm and -0.03±0.02 µm at 0°, 10° and 20°, respectively). Higher order RMS increased from fovea to peripheral retina with distance accommodation (mean change: 0.03±0.01µm at 10°, p=0.09 and 0.07±0.01µm at 20°, p=0.01), however there was no significant change in HORMS in periphery with accommodation.
Conclusions:
Significant myopic shifts observed in the periphery with accommodation compared to fovea that might be associated with biomechanical factors; e.g., changes in retinal curvature or axial elongation during accommodation. Accommodation might have little impact on higher order aberrations in periphery.