Perception of colour in unilateral tritanopia.

Publisher Website
Google Scholar
Abstract
The subject, a unilateral tritanope, described previously, was able to match every narrow-band light presented to his tritanopic eye with lights from a tristimulus colorimeter viewed in the adjacent field by the normal eye. In 2 regions of the spectrum (called isochromes) physically identical lights appeared identical to the observer''s 2 eyes. One isochrome was close to blue for the normal eye, the other was in the long-wave spectral region seen by the normal eye predominantly as red. Between these isochromes the normal eye required less than spectral purity to match, dropping to near zero purity at 560-570 nm. A mixture of the 2 isochromes that appeared purple to the normal eye appeared neutral to the tritanopic eye. Hence dichoptic matches grossly violate Grassmann''s additivity law. For the normal eye color naming conformed to typical normal results. For the tritanopic eye the following results were coherent with those found by dichoptic matching: the spectrum was divided into 2 regions by the achromatic neutral band. To the short-wave side, only the color names blue and white were ever used. To the long-wave side the predominant color names were red and white with some yellow. Spectral lights appeared neither red-blue nor greenish. Surrounding the test with an annulus either 430 nm, 650 nm or a mixture of these, failed to induce any greenish appearance, although the achromatic band shifted in the expected directions. There must be exactly 3 functionally independent, essentially non-linear central codes for color perception which are different from those suggested in existing theories of color perception.