What is a Colour Vision Deficiency ?
Colour vision defects are almost always inherited, although some forms can be acquired as a result of diseases or injuries. In the general population, about 8% of males and 0.5% of females have colour vision deficiencies.
Colour vision deficiency can range from mild to severe and most people can still see a large range of colours. It is extremely rare to be completely “colour blind”. Instead their perception of colour is different to the other people and they may have trouble telling the difference between certain colours such as:
- Shades of red and green (more common)
- Blues and yellow (less common)
Many people are unaware they have a colour vision deficiency, and the detection of these problems is important especially in children and adolescents, as their future career choices can be affected.
Examples of Ishihara Colour Vision Examination Plates :