Colour (color) blindness (colour vision deficiency, or CVD) affects approximately 1 in 12 men (8%) and 1 in 200 women in the world. Men are more prone to colour blindness.
There are different causes of colour blindness. For the vast majority of people with deficient colour vision the condition is genetic and has been inherited from their mother, although some people become colour blind as a result of other diseases such as diabetes and multiple sclerosis or they acquire the condition over time due to the aging process, medication etc.
Most colour blind people are able to see things as clearly as other people but they are unable to fully ‘see’ red, green or blue light. There are different types of colour blindness and there are extremely rare cases where people are unable to see any colour at all.
The most common form of colour blindness is known as red/green colour blindness and most colour blind people suffer from this. Although known as red/green colour blindness this does not mean sufferers mix up red and green, it means they mix up all colours which have some red or green as part of the whole colour. For example, a red/green colour blind person will confuse a blue and a purple because they can’t ‘see’ the red element of the colour purple. See the example of pink, purple and blue pen cases below to understand this effect.
Causes of Colour Blindness
Colour blindness is a usually a genetic (hereditary) condition (you are born with it). Red/green and blue colour blindness is usually passed down from your parents. The gene which is responsible for the condition is carried on the X chromosome and this is the reason why many more men are affected than women. The inheritance process is explained in more detail in the section Inherited Colour Vision Deficiency.
Colour blindness can be difficult to detect, particularly in children with inherited colour vision deficiency as they may be unaware that they have any problems with their colour vision. A child with a severe condition such as deuteranopia may seemingly be able to accurately identify colours which they can’t see (e.g. red) because they have been taught the colour of objects from an early age and will know for example that grass is green and strawberries are red even if they have no concept of their true colours.
You can also see your GP if you have any problems seeing colours. Your GP will ask about your symptoms and examine you. He or she may also ask about your medical history.
There are many tests available to measure colour vision defects but the most common is the Ishihara Plate test. This can test for red/green colour blindness but not blue colour blindness. This is the test most likely to be used for routine colour vision screening in schools or medicals.
Take the test here:
For more information please call us or visit
McKenna & Scott Exclusive Optometrists in Pinelands.
Tel: 021 531 1953