Help and frequently asked questions

What causes colour vision impairment?


Colour vision impairment is usually an inherited condition, which tends to affect how you see shades of green and red. When light enters your eye, it passes through to the colour-sensitive cells on the retina called 'cones'.

There are three different types of cone cells - blue, green and red - and they interpret the colour combinations you see before sending images onto the brain via the optic nerve. However, if the cones are not functioning properly or you are missing a certain type of cone, it will cause problems with how you perceive colours. If you have inherited the condition, it will not get worse as you get older but the condition can range from mild to severe. My colour vision impairment isn't inherited, what could it be?

If you begin experiencing a colour vision deficiency and the condition is not inherited, you should visit an optometrist as soon as possible to find out why. The gradual fading of colours is a common eyesight problem as you get older, so this could be a contributing factor, although there are environmental and health-related issues that could also be having an impact. People who suffer colour vision deficiencies due to an underlying health problem tend to have issues seeing blue and yellow colours rather than red and green.


Some medications, including Viagra and tuberculosis treatments, can cause colour vision abnormalities.


There is a chance you have been exposed to chemicals that lead to colour vision impairment. Carbon monoxide, carbon disulphide and some lead-based chemicals can cause colour blindness.

Eye conditions

Glaucoma, age-related macular degeneration, cataracts and inflammation of the optic nerve can create problems with colour perception. Some of these can cause serious issues with your vision, so make sure to book an eye test.

Other conditions

Diabetes, alcoholism and sickle cell anaemia are some of the diseases that can affect your colour vision.