Colour blindness sounds like a devastating condition - who'd want to go through life feeling like they were watching an old black-and-white television set? Worse, it's reasonably prevalent; about 7 per cent of men are affected, although the ratio for women is lower, at 2 per cent. Bad genes are the single biggest cause of colour blindness, particularly mutations of the X chromosome, which explains why more men suffer from the condition; men have only one X chromosome to put to use while women have a second, which can mask a deficiency. But the affliction doesn't have to be inherited. Accidents, especially those that traumatise the retina or brain, and excessive exposure to UV rays can result in people with perfect vision going colour blind later in life. The good news is 'colour blind' rarely means exactly that - 'colour disadvantaged' would be a more appropriate term. The vast majority of colour blindness falls into the anomalous trichromacy category: a scientific way of saying someone has more trouble distinguishing reds, greens or, in rare cases, blues than is normal. Most people with anomalous trichromacy go through life with no inkling they have any form of colour blindness; often optometrists can only pinpoint the condition through highly specialised tests. Others can have trouble distinguishing red or green objects in low light, when they may appear dark blue or black. The next step on the colour-blindness scale is dichromacy, which occurs in individuals who lack some of the cone or photoreceptor cells in the retina that determine how we see the world. Dichromatics are usually aware they have a vision deficiency and are unable to make out different sections of the colour spectrum. Reds and blacks may appear exactly the same, for example, or oranges and greens as only slightly different shades of yellow. But even they're better off than monochromats, who suffer the most severe form of colour blindness. Usually, because they have only a single type of cone in their retina, a monochromat is unable to recognise different colours or hues, perceiving things only in terms of brightness. This is the case only for a ten-thousandth of the population. Being colour blind does have its advantages. Because colours are tougher to make out, colour-blind individuals tend to have a heightened awareness of texture, surface and shape, meaning they're more adept at picking things out of camouflage. Second world war officers frequently had colour-blind counterparts analyse aerial photos. Colour blindness is no inhibitor to intellectual or sporting success. Most of the early research into its causes and effects can be credited to John Dalton, a renowned British chemist who was colour blind and who lay the foundations for modern atomic theory. The infamous baby-blue eyes of renowned actor Paul Newman are colour blind. Legendary golfer Jack Nicklaus is also colour blind, though the condition has had no perceptible impact on his game except his rumoured inability to distinguish between over par (usually green) and under par (usually red) points on course scoreboards.