Abstract

We analyze the influence of the optical imaging quality of the eye on contrast threshold perception using both physical and psychophysical data for the same human subject. We have completely characterized the optical quality of human eyes by means of a hybrid optical-digital method and a phase retrieval algorithm that allows us to obtain the point spread function (PSF) and the wave aberration of an individual eye. From the wave aberration, we can calculate the 2-D modulation transfer function (MTF) in any conditions of luminance which are directly related to the pupil size, defocusing, etc. We have also obtained 2-D contrast sensitivity functions (CSF) for the same subjects with a forced-choice staircase method for different values of the average luminance of the test. The link between both kinds of data is a 2-D model for the theoretical determination of threshold contrast that considers the different stages of the early visual process. In this way we are able to evaluate the relative influence of both the optical and neural stages on contrast sensitivity for any desired luminance level, defocusing, etc.

© 1989 Optical Society of America