Stiles–Crawford effect
Stiles–Crawford effect of the first kind
directional effect
decrease in the brightness of a light stimulus with increasing eccentricity of the position of entry of a pencil of light through the pupil
Note 1 to entry: When the variation is in hue and saturation instead of in brightness, the effect is called "Stiles–Crawford effect of the second kind".
Note 2 to entry: The Stiles–Crawford effect is predominantly present for cone vision.
Note 3 to entry: This entry was numbered 845-02-15 in IEC 60050-845:1987.
Note 4 to entry: This entry was numbered 17-1268 and 17-327 in CIE S 017:2011.