Types of
color blindness
Red-green, blue-yellow, and complete color blindness—what each type means, how common it is, and free screening tests.
Protanopia
Missing L-cones. Reds appear dark or black. ~1% of men.
Free test → Red-weakProtanomaly
Partial red-axis weakness. Less severe than protanopia.
Free test → Green-blindDeuteranopia
Missing M-cones. Most common severe red-green CVD (~1% of men).
Free test → Green-weakDeuteranomaly
Partial green weakness. ~5% of men—the most common CVD overall.
Free test → Blue-yellow blindTritanopia
Missing S-cones. Rare (~0.01%). Blues and yellows confused.
Free test → Blue-yellow weakTritanomaly
Partial blue-yellow weakness. Less severe than tritanopia.
Free test → CompleteAchromatopsia
No working cone cells. Vision in shades of gray only.
Free test →Red-green vs blue-yellow color blindness
Red-green color blindness (protanopia, protanomaly, deuteranopia, deuteranomaly) affects roughly 8% of men. It is X-linked and by far the most common category. Blue-yellow color blindness (tritanopia, tritanomaly) is rare and affects men and women equally. Achromatopsia is complete color blindness—vision in grayscale only.
Screen for all types with our free color blind test, simulate how UI looks under each filter on the all-types simulation page, or read the science of color blindness guide.