What is colour deficiency?
Colour deficiency occurs when your ability to distinguish colours and shades is different from normal. Colour deficiency is more common in males than females, with one in 10 males having a colour deficiency.
What causes colour deficiency?
Colour deficiency results from an imbalance in the three kinds of cones in the retina that allow us to perceive colour. It is usually inherited, and can also result from certain diseases, trauma, or as a side effect of certain medications.
What types of colour deficiency exist?
There are three types of colour deficiencies: two different kinds of red-green deficiencies, and one called blue-yellow deficiency.
Red-green deficiencies: are by far the most common and are usually inherited. This may result in the inability to distinguish between certain shades of reds, browns, pinks and oranges, or greens and blues.
Blue-yellow deficiency: is very rare and is usually acquired secondary to damage to the optic nerve and results in the inability to distinguish between certain shades of blue, as well as shades of yellow.
People with complete colour blindness see objects in shades of black, white, and grey.
How is colour deficiency detected?
Children who are colour deficient are generally unaware of their condition. They assume that everyone sees things the way they do. As a result, a complete optometric examination, including a test for colour vision, is recommended for every child. The test for colour deficiency is a relatively simple one, typically involving the viewing of a series of coloured plates with numbers or designs.
A person with a colour deficiency will either see a different number of designs or will be unable to distinguish the figures.
When should a person be tested for colour deficiency?
Every child should be checked for colour deficiency by at least age five. It is important to detect colour deficiency early because colour coded learning materials are used extensively in the primary grades.
Can colour deficiency be cured?
Unfortunately, a cure for colour deficiency has not been discovered. A person with a colour deficiency can, however, be taught proper colour naming and to accurately distinguish colours. For example, you can be taught to recognize the brightness and location of a traffic light rather than the colour itself. It is sometimes possible to increase the ability to distinguish colours with the use of special filters.