Usually, when people describe someone as seeing everything in black and white they mean that this person is rather simplistic and decided in their views. However, there is a very rare condition, a form of colour blindness called achromotopsia. This derives from a Greek phrase meaning 'without colour' and in severe cases it means that you see everything in black, white and shades of grey. Some people with this condition have no colour vision at all, so it would be something like seeing the whole of life as a black and white film. If you have this condition, there are often problems with poor eyesight and sensitivity to light as well.

Achromotopsia is rare; much more common, especially in men, is ordinary colour blindness. The most typical problems here are in distinguishing between red and green, or sometimes blue and yellow. This can cause difficulties, but isn't necessarily linked to other health problems.