Colour Blindness

Colour vision deficiency

Colour vision deficiency (sometimes known as colour blindness) is an inability to distinguish colours fully. It is commonly an inherited condition and carried through the mother’s genes (whose vision may appear normal) to sons in the main.

Non-inherited colour deficiencycan be a symptom of diabetes, multiple sclerosis and cardiovascular diseases (including high blood pressure), some liver diseases and many eye diseases. These underlying conditions can affect the cones or the nerve pathways from them to the brain. In these cases, colour vision may be temporarily or permanently altered, often in one eye at a time. Difficulty in colour discrimination may be noticed along with other visual problems.Since colour vision changes can be an early sign of disease or a side effect of prescribed medication, if you are aware that your appreciation of colours is changing, it is important to discuss it with your optometrist.

Managing colour deficiency

Although nothing can replace a faulty mechanism in the retina of the eye, many colour defective people do learn ways of compensating for their difficulty over time. Many people find help, albeit limited, identifying certain colours that they would otherwise misname, with the aid of a small red or red-mauve filter of transparent plastics or glass held in front of the eye. This is best tried at home with a selection of transparent coloured materials, but it is not usual to prescribe tinted spectacles for this purpose, since only one eye must use the filter. A red tinted contact lens (branded the ‘Chromagen’ lens) can be worn in one eye to help colour recognition, but the results cannot be guaranteed.

Further information

If you would like more information on this special type of contact lens or if you think you or your child may be colour deficient, please make an appointment to see one of our optometrists.