What causes color vision defects?
Color vision depends on the absorption of light by visual pigments contained within specialized cells in the eye called photoreceptors. There are two types of photoreceptors: rods and cones. Rods, which provide vision in dim light, have no ability to distinguish between colors. Cones are responsible for color vision. There are three different types of pigment in the normal eye. Color vision occurs within the visual part of the brain compares electrical signals from the different types of cones. © University of Illinois Board of Trustees Usage without written permission is prohibited. Defects in color vision are either inherited or acquired. Inherited defects result mainly from missing or incorrect visual pigments. There are different types of inherited defects, with different levels of severity. Color vision defects sometimes can be acquired, as a result of eye disease or normal aging or as a side effect of certain medications. In acquired defects, other parts of the eye besides cones
