Colour Blindness
Poor colour vision is a failure to distinguish between certain shades of colour. Although most people say colour blindness, real colour blindness is just a lack of colour vision. Seeing only black and white or in shades of grey is very rare, but can be found in both sexes. There are two types: Typical: Complete failure to discriminate between any colour variations, usually associated with other severe vision impairments. Atypical: Colour sensitivity is so low that only very clear colours are perceived, but there is little other visual impairment. Most people with poor colour vision can’t tell apart certain shades of red and green in dim light. Some people can’t distinguish between red and green shades even in bright light. But this all depends on the intensity of the colour and the brightness of the light conditions at the time. For instance, people with poor colour vision will always be able to tell that a bright green crayon is green, if they are standing outside in bright sunlight. But if they are standing under a 40-watt bulb then they might think it’s a brown crayon. And if it was a green object, which wasn’t as colourful as a crayon, they could even think it was red.
