Colour blindness

Colour blindness, sometimes known as colour vision deficiency, isn't typically a cause for concern, although it can cause some challenges to everyday life.

If you're worried that you or someone you know might be colour blind, our guide has all the information you need to understand colour blindness.

What is colour blindness?

Colour blindness is often mistaken for being unable to see colour at all. However, this is exceptionally rare. Instead, colour blindness is more of a difficulty in distinguishing between different colours.

It’s a genetic condition usually passed through families and can be present from birth. In some cases, it can develop later in life.

Usually, being colour blind is not a sign of anything more serious. Most people can adapt to colour blindness and live a normal life with few challenges.

Colour blindness test

If you think you or your child may be colour blind, you can ask your optician to test for signs. You should particularly consider getting a test if your colour blindness has started suddenly or is getting worse.

Colour blindness tests aren't usually part of the standard NHS eye test, but you can ask for one if you feel you need it.

The two main colour blindness tests are:

• The Ishihara test, where you identify numbers contained within images made up of different coloured dots
• Colour arrangement, where you arrange coloured objects in order of their different shades

Several online tests using similar techniques could help detect a possible problem. Even so, it's better to ask for a proper test from your optician if you're concerned.

Colour blindness types

Colour blindness means that you don't see colours the same way as most people. It can affect how you see differences between colours, the brightness of colours, and different shades of colour.

Different types of colour blindness have other effects:

Causes of colour blindness

Most cases of colour blindness are due to a genetic fault that parents pass on to their child, usually from mother to son.

The fault affects the retina’s colour-sensitive cells, known as cone cells. The cones can be damaged or missing altogether, resulting in difficulty differentiating between specific colours.

In rarer cases, a degree of colour blindness can develop in later life because of:

• Eye conditions including glaucoma, age-related macular degeneration, and cataracts
• Underlying health conditions like diabetes and multiple sclerosis
• Medication side effects
• Exposure to harmful chemicals

It's common for people to struggle more with telling colours apart as they get older, which is a normal part of ageing.

Colour blindness symptoms

As well as trouble telling the difference between certain colours, colour blindness can cause colours to appear less vivid.

How you see colours depends on the severity and type of your colour blindness. If you notice any changes in how you see colours, speak to your optician.

Most people adapt well to living with colour blindness, which doesn't typically get worse over time.

Treating colour blindness

There's currently no known cure for genetic colour blindness. Instead, you can learn ways to adapt to living with your condition.

Colour blindness glasses or contact lenses are one option. They have tinted lenses to help your eyes take in different coloured light.

If an underlying illness is a reason for your colour blindness, then treatment for the condition may improve your colour blindness.

When to get medical advice

If you know colour blindness runs in your family, it can be a good idea to get children tested at an early age to find out whether they have inherited it.