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Detect Color Blindness

Types of Color Blindness

By The Detect Color Blindness editorial team Last reviewed

"Color blindness" is rarely total. Most people with it see color, just a narrower range, because one type of cone in the retina is missing or shifted. Which cone is affected, and how strongly, defines the type.

The three color axes

Human color vision uses three cone types, long (red), medium (green) and short (blue) wavelength. A deficiency in any one shifts how you separate colors:

  • Red-green (protan and deutan), the L or M cones. By far the most common, and X-linked, so it mainly affects men.
  • Blue-yellow (tritan), the S cones. Rare, and affects men and women equally.
  • Total color blindness (monochromacy), little or no cone-based color at all. Extremely rare.

Not sure which applies to you? The quickest answer is to take the color blind test, it estimates your axis and strength in about a minute.