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What Do You Know About Colour Blindness?

Imagine living in a world of murky greens where shades of blue, brown and yellow take precedence over vibrant red hues. Now, imagine living in a monochromatic universe dominated by shades of gray, much like an old television set. For some people, discriminating between colours is a near impossible task. Do you fear you or your child may have a colour vision defect? We at The Eyewear Place can help with the diagnosis!


Abnormalities in colour perception are the result of defects in the genes responsible for developing the photopigments in our cone cells (cells responsible for colour vision). Some defects alter sensitivity to colour, while others can result in total absence of pigmentation.


While primarily hereditary, colour vision defects can also arise as a consequence of physical or chemical damage to the eye, optic nerve or parts of the brain that process colour information. Diseases such as diabetes and multiple sclerosis, as well as visual impairments because of old age (e.g. cataracts), can all have an impact on the way we see colour. What Are The Different types?

Depending on the type of defect and the cone that is affected, problems may arise with red, green or blue colour vision. There are three main types of colour vision deficiencies:

  • Red-green: the most common types of hereditary colour blindness are due to the loss or limited function of photopigments in either the red or green cone. Patients with reduced sensitivity to red light commonly perceive red, orange and yellow as a shade of green, while shades of yellow and green appear redder to eyes with reduced sensitivity to green light.

  • Blue-yellow: patients with blue-yellow colour blindness lack or have functionally limited blue-cone cells. Blue typically appears green, while yellow takes on violet or light gray.

  • Complete: patients diagnosed with ‘total colour blindness’—also known as monochromacy—don’t experience colour at all. The most severe and rare form of all colour vision deficiencies, complete colour blindness can also affect a person’s visual acuity (clearness of vision).


On average, colour blindness affects 8% of men and 0.5% of women worldwide. The genes responsible for the most common types of colour vision deficiencies are on the X chromosome. Since females have two of these chromosomes, a functional gene on only one of the pair is enough to compensate for the loss of the other. However, the same cannot be observed in males since they only have one X chromosome.

The effects of colour blindness can be mild, moderate or severe, and can make simple tasks like reading a pie chart or selecting ripe produce a challenge. Many people with less severe types may not even be aware that they see the world in a different light—unless they get professionally tested. At The Eyewear Place in Fort McMurray and Lloydminster, Alberta, our experienced optometrists offer complete eye examinations, including colour vision tests, to determine your ocular strength. Don’t let colour blindness go undetected! Call The Eyewear Place to set up an appointment with your trusted eye doctor today.



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