Is there treatment for colour vision deficiency?
There is no treatment for abnormal colour vision, although recent studies offer a prospect for gene therapy in the future (ref 61).
Glasses with coloured lenses or coloured contact lenses are promoted as an aid for those with abnormal colour vision. These can help pass colour vision tests but do so by altering the colours in the tests, not by improving colour vision. In general they do not work in the sense of restoring the ability to see more colours. If they work at all it is by changing the relative brightness of different colours (refs 62, 63).
However, coloured filters can be useful in specific tasks. For example it is often difficult for medical practitioners and optometrists who have abnormal colour vision to distinguish melanin pigment spots from small haemorrhages when examining the retina of the eye by ophthalmoscopy. Viewing alternatively with orange and green (red-free) filters can enable the distinction to be made, (ref 21) although this might not work for those with a red (protan) colour vision deficiency, because red already looks dark to them.
There are spots on the retina of this eye. If you have normal colour vision they are easily seen as haemorrhages because they are red (left). But if you have abnormal colour vision the red colour is not seen (right) and the spots might be thought to be melanin pigment spots. Using coloured filters can help most practitioners with abnormal colour vision make the distinction.