Did you know?
Colour blindness could more accurately be called colour vision deficiency. It is usually due to a problem with the photoreceptor cells, called cones, that are in your eye (you actually have about 6 to 7 million of them in each eye). Often people are born with colour blindness, but it can also present as the result of an accident or trauma to the eye.
Interestingly, some colour blind people are able to see colour variations that a person with 'normal' colour vision cannot see!