What causes colour blindness and how does it affect vision?

Colour blindness is caused by a lack of or malfunction in certain colour-detecting cells in the eye, affecting colour perception.

Colour blindness, also known as colour vision deficiency, is primarily a genetic condition caused by an abnormality in the genes responsible for the development of one or more of the three sets of colour sensing cones in the eye. These cones are photoreceptor cells located in the retina, which is the light-sensitive layer at the back of the eye. Each set of cones is sensitive to different wavelengths of light, allowing us to perceive different colours.

In a person with normal colour vision, the three sets of cones work together to perceive a full spectrum of colours. However, in a person with colour blindness, one or more sets of cones may be missing or not functioning properly. This can result in difficulty distinguishing between certain colours. The most common form of colour blindness is red-green colour blindness, where individuals struggle to differentiate between red and green hues.

Colour blindness can also be caused by physical or chemical damage to the eye, the optic nerve, or parts of the brain that process colour information. Certain medications, ageing, and some health conditions like diabetes and multiple sclerosis can also lead to colour vision deficiency.

The impact of colour blindness on vision varies depending on the type and severity of the condition. Some people may only have difficulty distinguishing between certain shades of colours, while others may not see colours at all. This can make certain tasks challenging, such as reading colour-coded information, driving, or choosing and preparing food. However, many people with colour blindness develop strategies to compensate for their colour vision deficiency and can lead normal lives.