Abstract

The intensity and color of a light determined psychophysically depends on where the light enters the eyes pupil, (the Stiles-Crawford effect¹⁰). This effect occurs due to the physical orientation and waveguide properties of the cone photoreceptors. In principle the measurement of cone alignment and orientation is a powerful clinical technique, providing direct information on the status of the outer retina. The outer retina is very sensitive to retinal and systemic disease, due in part to its high metabolic activity. Healthy photoreceptors are well oriented, and the orientation is maintained by an active process, with cones recovering their orientation following insult or disease⁴,⁵,⁸,⁹. In practice it has proven to be dificult to obtain a full map of cone orientation in a naive subject, and this has limited the use of the Stiles-Crawford effect for clinical research.

© 1992 Optical Society of America