What is colour blindness?

Colour blindness is a vision problem that means you have trouble seeing shades of red, green, or blue or a mix of these colours. It happens when there's a problem with some of the cells found in the layer of nerves (retina) at the back of the eye.

Almost always, the problem runs in families and is something you are born with. It's found more often in males than in females. Colour blindness that you are born with can't be treated or corrected. But you can learn ways to adapt to being colour blind.

What happens when you have colour blindness?

Colour blindness affects people in different ways. You may be able to see some colours or a few shades of colour but not others. Or you may see enough colours that you may not know that you are colour blind until you have a routine eye exam. In rare cases, some people see only black, white, and grey.

For some people it may be hard to tell if a piece of red meat is rare or well done. It can make food look like it's not good to eat. It can also be a challenge to see traffic lights or use technology with red and green LED lights.

How is it diagnosed?

The doctor will have you look at pages in a book or plates that are designed to check how well you see colours.

How can you adapt?

There are ways to adapt to the challenge of being colour blind. Here are some things you can try.

• Learn to look for cues like brightness or location, rather than colours. For example, you can learn the order of the three coloured lights on a traffic signal.
• Wear coloured contact lenses. These may help you see differences between colours. But these lenses don't provide normal colour vision. Be aware that they can distort objects.
• Wear glasses that block glare. You may be able to see differences between colours better when there is less glare and brightness.