Types of Color Blindness

Normal color vision uses three types of cone cells, sensitive to long (red), medium (green) and short (blue) wavelengths. Color blindness happens when one cone type is missing or works differently.

Red-green color blindness

By far the most common group. Protan types affect the red-sensitive cones; deutan types affect the green-sensitive cones. Read the full guide to red-green color blindness, or seewhat colorblind people see with each type.

DeuteranomalyReduced sensitivity to green light DeuteranopiaGreen-sensitive cones absent or not working ProtanomalyReduced sensitivity to red light ProtanopiaRed-sensitive cones absent or not working

Blue-yellow color blindness

Rare when inherited, and more often acquired through eye disease or aging. Tritan types affect the blue-sensitive cones.

TritanomalyReduced sensitivity to blue light TritanopiaBlue-sensitive cones absent or not working

Complete color blindness

Achromatopsia (rod monochromacy) is very rare, affecting about 1 in 30,000 people. People with it see little or no color and usually also have reduced sharpness of vision and sensitivity to light. Our plate tests are not designed to detect it.

Note: this is a screening, not a diagnosis. Online tests can’t control your screen’s colors or brightness, so confirm any result with an eye care professional. Medical disclaimer · How the test works

More color vision tests

Color blind testFull screening: red-green and blue-yellow, with type and severity.Red-green color blind testDeeper check for protan and deutan types.Tritanopia testBlue-yellow (tritan) color vision screening.Color blind test for kidsShapes instead of numbers, for children who can’t read digits yet.Reverse color blind testHidden-figure plates that color blind people can see more easily.Color blind simulatorSee any photo the way people with color blindness see it.