Abstract

Stiles and Crawford (1933) showed sixty years ago that the sensitivity of the retina varies with the place of entry of the light in the pupil, and thus with the direction of incidence of light upon the retina. Sensitivity is generally greatest near the centre of the pupil and progressively decreases for more eccentric entry points. This phenomenon is known in the literature as the Stiles-Crawford effect of the first kind (SCE I). The hue shift associated with the SC-effect was discovered by both investigators (Stiles 1937) in a further study of the retinal direction effect. This effect is called the chromatic Stiles-Crawford effect, often also referred to as the Stiles-Crawford effect of the second kind (SCE II).

© 1993 Optical Society of America