Ocular aberrations of human eyes

We have modified an aberroscope technique, developed by Horvland and Howland, to investigate the influence of: 1. Refractive error and 2. Accommodation on ocular aberrations. These authors analysed drawings made by subjects of retinal shadows generated by a rectangular grid pattern mounted between crossed +5 D and -5 D cylindrical lenses and a point light source. We have developed the method further by using a fundus camera to photograph these shadow pattens. Preliminary data show that third-order- coma-like aberrations are usually the dominant foveal aberrations, and that there is a trend from positive spherical aberration torwards negative spherical aberration in some accommodating eyes that have been obseeved previously with other measurement techniques