Colour Blindness – what colours do you see?

An estimated 2.6 million Canadians are colour blind. This is because of a missing or mutated gene on their X chromosome.  One in 12 men (8%) and 1 in 200 women (0.5%) are colour blind, and the condition can have an impact on their education, grades, career choice, and even career growth, as well as how they see and engage with visuals such as charts, photographs, and presentations. Moreover, there are many professions where colour blindness could be a non-starter, including a professional pilot, firefighter, electrician, or police officer to name a few.


Colour blindness, also known as reduced colour perspective condition, comes in different forms, with the most common a form of red/green colour blindness.  Blue-yellow colour blindness is less common, while complete colour blindness is quite uncommon. The primary cause of colour blindness is a lack of light-sensitive pigments in the cones of the eye. Colour blindness is genetically passed on through the X chromosome. However, diseases such as diabetes can affect colour vision, as can age. Although genetically caused colour blindness cannot be cured, visual aids and other strategies can help. In addition, some people may benefit from special contact lenses or glasses.


The symptoms of colour blindness can range from mild to severe. Many people have such mild symptoms that they are unaware that they have a colour deficiency. Parents may only notice a problem with a child when he is learning his colours. The symptoms include:

  • Trouble seeing colours and the brightness of colours in the usual way;
  • Inability to tell the difference between shades of the same or similar colours. This happens most with red and green, or blue and yellow.

In practical terms, people affected by colour blindness can only correctly identify five crayons from a standard box of 24. Or it’s challenging to colour coordinate clothing (does this tie match?) The impacts are real and tangible on one’s quality of life.

Except in the most severe form, colour blindness does not affect the sharpness of vision. The inability to see any colour at all and to see everything only in shades of gray is called achromatopsia. This rare condition is often associated with amblyopia (or lazy eye), light sensitivity, or poor vision.

Want to experience what the world is like for someone who is colour blind? If so, check out this interactive, widely accepted test here.