Library · Physiology
Color vision
Make it clearer
Seeing in color does not depend on a single sensor. In the retina, the layer at the back of the eye that captures light, there are cells called cones, and they are not all alike: they carry three different visual pigments, usually named red, green, and blue, or L, M, and S cones. Three different detectors, and color comes out of the mix of their three signals.
What sets those three types apart is the band of the spectrum each one absorbs best. Light of a given color stimulates some of them more than others, and the color we perceive comes out of that ratio. The cones are the ones that carry that color information.
If one type of cone loses its function, the mix is incomplete and vision becomes dichromatic, made from two signals instead of three. That is what happens in protanopia and in deuteranopia, the two most common forms.
In brief
Color vision comes from combining the signals of three cone visual pigments: red, green, and blue, or L, M, and S cones.
Three different detectors, and color comes out of the mix of their three signals.
Each type of cone absorbs a different band of the spectrum best, and it is the cones that carry color information in the retina.
When one type of cone loses its function, dichromatic vision results: the most common forms are protanopia and deuteranopia.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingColor Vision, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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