Total occlusion does not disrupt photoreceptor alignment.

Previous measurements of the photopic Stiles-Crawford function (SCF) in human observers prior to, during, and after (1) total occlusion, and (2) displacement of the eye's pupil, indicate by inference the presence of a phototropic mechanism which actively maintains photoreceptor alignment. In an attempt to replicate and expand the conclusions of these experiments, full SCFs were measured on three normal eyes and one abnormal eye prior to and after at least 6 days total occlusion. Counter to previous reports, total occlusion induced few if any alterations in the SCF rho value in both the normal and abnormal eyes.