colour vision

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colour vision The ability of the eye to detect different wavelengths of light and to distinguish between these different wavelengths and their corresponding colours. In the mammalian eye this is achieved by the cone cells, which are located in and around the fovea near to the centre of the retina. The cone cells contain the light-sensitive pigment iodopsin, which – according to the trichromatic theory – exists in three forms, each form occurring in a different cone cell. Each form of iodopsin is sensitive to either red, blue, or green light. The relative stimulation of each type of cone will determine the colour that is interpreted by the brain. For example, if red cones and green cones are stimulated to an equal extent, the colour interpreted by the brain is yellow. See also colour blindness.

The compound eye of certain insects is also capable of colour vision.