The employers guide to colour blindness

The employers guide to colour blindness Safety Forward

People with colour vision deficiency find it difficult to identify and distinguish between certain colours. It’s sometimes called being “colour blind”, although total colour blindness (an inability to see any colour) is very rare.

It is estimated that a person with normal colour vision can see up to 1 million distinct shades of colour, but a person who is colour blind may see as few as just 10 thousand colours (1% of the norm). There are different kinds of colour vision problems and different degrees of severity and our latest article looks an employers guide to colour blindness and what should be done to assist and support employees.

Types of Colour Blindness

  • Deuteranomaly is the most common type of red-green colour blindness. It makes green look more red.
  • Protanomaly makes red look more green and less bright.
  • Protanopia and deuteranopia both make you unable to tell the difference between red and green at all.

Less commonly, people with colour blindness can’t distinguish between shades of blue and yellow.

What causes colour blindness?

Inherited disorder-Inherited colour deficiencies are much more common in males than in females and you can inherit a mild, moderate or severe degree of the disorder. Inherited colour deficiencies usually affect both eyes, and the severity doesn’t change over your lifetime.

Colour blindness can also happen if your eyes or the part of your brain that helps you see colour gets damaged. This can be caused by:

  • Eye diseases, like glaucoma or macular degeneration
  • Brain and nervous system diseases, like Alzheimer’s or multiple sclerosis
  • Some medicines, like Plaquenil (a rheumatoid arthritis medicine)
  • Eye or brain injuries


Employer responsibility

If an employer has employees whose colour vision is important for safety critical purposes then colour vision testing is crucial in deciding on their fitness for work. When colour vision needs are associated with product quality then colour vision testing is valuable to avoid costly errors and safety issues. If a colour vision risk assessment is required to evaluate the ability of an individual to perform one or more specific tasks, this is often carried out at the pre-employment stage. For some occupations, annual checks for acquired defects may be desirable.


Colour blindness can have an impact on many types of jobs which you might not initially think would cause problems. Employers and businesses should therefore consider their processes and procedures, not only to support colour blind colleagues but if they are producing information – brochures, presentations, equipment etc, then these outputs need to be suitable for everyone. For instance, there are special types of software available to help transform computer screen displays into colours that are distinguishable for employees with colour blindness.

Employers must make positive and proactive steps to remove, reduce or prevent the obstacles a colour-blind worker or job applicant faces.

For further information on employers guide to colour blindness and any other health and safety issues, please contact us here.