Cortical Defects in Color Processing

Much has been learned about the retinal coding of color information since Young first proposed his mechanism for retinal color discrimination in 1801. Relatively little however has been learned about how our cortex detects and processes color information. Clincal studies have been of limited usefulness due to the small number of patients reported with anatomic correlation. They have served also as a source of confusion due to a marked variation in the types of tests used to clinically evaluate the patients as well as a marked inconsistency in the language used to name the different tvpes of problem that have been reported. In the following discussion a schema is presented that tries to explain how processing of color information might normally progress. Using this schema, one can more easily understand the types of color vision problems that one sees clinically, as well as the different types of tests one can do to demonstrate these various problems.