Are you colour blind?

Most of us share a common colour vision sensory experience. Some people, however, have a colour vision deficiency, which means their perception of colours is different from what most of us see. The most severe forms of these deficiencies are referred to as colour blindness.

Test your colour vision


There are three main kinds of colour blindness, based on photo pigment defects in the three different kinds of cones that respond to blue, green and red light. Red-green colour blindness is the most common, followed by blue-yellow colour blindness. A complete absence of colour vision -total colour blindness - is rare.

What causes colour blindness?

Colour blindness is mostly hereditary and affects approximately every 1 in 12 men (8%) and 1 in 200 women (0.5%). Men are much more likely to be colour blind than women because the genes responsible for the most common, inherited colour blindness are on the X chromosome. Males only have one X chromosome, while females have two X chromosomes. In females, a functional gene on only one of the X chromosomes is enough to compensate for the loss on the other.

Some people also acquire the condition as a result of long-standing diseases, such as diabetes, multiple sclerosis, some liver diseases and other eye diseases.

Is there a cure for colour blindness?

There is no cure for colour blindness. However, people with red-green colour blindness may be able to use a special set of lenses to help them perceive colours more accurately. These lenses can only be used outdoors under bright lighting conditions.

Visual aids have also been developed to help people cope with colour blindness. There are iPhone and iPad apps, for example, that help people with colour blindness differentiate among colours. Some of these apps allow users to snap a photo and tap it anywhere on the image to see the colour of that area. More sophisticated apps allow users to find out both colour and shades of colour. These kinds of apps can be helpful in selecting ripe fruits such as bananas, or finding complementary colours when picking out clothing.


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