Evaluating the role of cone directionality in image formation

摘要

The Stiles-Crawford effect can significantly improve the optical performance of the human cones. In agreement with others we find that this improvement tends to be largest for out of focus images, although the actual point of maximal improvement varies signigicantly with the actual aberration structure of the eye in question. We found subject with the largest improvement for both hypermetropic and myopic defocus. As expected the role of the Stiles-Crawford is largest when the pupils are large, image quality for small pupils showed little effect of SCE apodization. Surprisingly we did not find a decrement in calculated retinal image quality for the observers with decentered SCE functions as opposed to retinal image quality calculated if they has a centered SCE function. As previously reported we find a number of individuals with very decentered SCE functions (in this sample up to 3 mm decentered), and this decentration is stable over time. One of our original hypotheses was that retinal image quality helped to provide a stimulus for this decentration, but we were not able to reject the hypothesis that the image quality was equal when apodized centrally vs peripherally.