What is the most common type of colour blindness?

Red-green colour blindness is by far the most common, covering the protan and deutan types.

How common is colour blindness?

It affects roughly 1 in 12 men and about 1 in 200 women, mostly the inherited red-green forms.

Can you be fully colour blind?

Total colour blindness, called achromatopsia, exists but is very rare. Most people with a deficiency still see many colours.

Types of Color Blindness Explained

Quick answer: The main types are red-green (protan and deutan), which is by far the most common, blue-yellow (tritan), which is rare, and total colour blindness, which is very rare. Most cases are inherited and affect men more than women.

Check your own colour vision: open the colour blindness test.

Red-green deficiency

This is the common one, split into protan types (reduced or absent red perception) and deutan types (green). It affects about 1 in 12 men and 1 in 200 women, because the genes involved sit on the X chromosome.

Blue-yellow deficiency

Tritan types affect blue and yellow perception. They are much rarer and affect men and women about equally.

Total colour blindness

Achromatopsia, seeing little or no colour at all, is very rare and often comes with other vision effects. Most people described as colour blind actually have a partial red-green deficiency.

How to check

An online plate test gives a quick indication, but only an optometrist can diagnose the exact type and severity. Take the colour blindness test to see how you do.