Colour blindness is often used to describe all forms of colour vision deficiency and does not always mean complete colour blindness. Total colour blindness is rare whereas the inability to distinguish between certain colours is much more common.
Colour blindness is usually inherited from family members and is usually present from birth, although it can develop later. Colour blindness is rarely serious and people usually learn methods to live with the condition.
Usually those with colour vision deficiency find it hard to tell the difference between red, green and yellow, which is usually known as ‘red-green’ colour deficiency (or Deuteranopia). It is much more common in men affecting approximately 1 in 20 compared to 1 in 200 women.
People with this kind of colour blindness may have trouble seeing different shades of purple, may see colours duller than they are, be unable to tell the difference between red and black and find it difficult to see the difference between reds, greens, yellows, browns and oranges.
Some people have particular difficulty with blues, yellows and greens known as ‘blue-yellow’ colour vision deficiency (or Tritanopia) but this is much rarer than ‘red-green’. Those who are completely colour blind (or have Monochromacy sight) see everything in greyscale.
Take a look at our illustrations below:
This is the original image.
This is how the image appears to those with red-green colour vision deficiency or Deuteranopia.
This is how the image appears to those with blue-yellow colour vision deficiency or Tritanopia.
This is how the image appears to those with complete colour blindness or Monochromacy sight.
Opticians don’t test for colour blindness in routine eye tests but if you think your child may be colour vision deficient your local optician can test for it. It is particularly important to get your child’s eyes tested if the condition has started suddenly or is getting worse.
The two most common tests for colour blindness are the Ishihara test and the colour arrangement test.
The Ishihara test is when the patient is asked to identify numbers within pictures of coloured dots.
The colour arrangement test is where the patient is asked to arrange coloured objects in order of their different shades.
There is an online test on the Enchroma website to check for the most common type of colour blindness (red-green) by comparing your results with other people. It is intended as a guide and may give some indication, however it is important to attend regular eye tests and raise any concerns you may have with your optician.
There is currently no cure for colour blindness that is inherited from a family member but most people adapt to living with it over time. To make it easier to live with you might like to try:
Glasses with tinted lenses may help those with colour vision deficiency in distinguishing between colours. If you’d like to try this discuss it with your optician who may be able to guide you through your options, although this treatment does not work for everyone.