Colour-blindness: What you need to know

By age four, my son Bode could count to 20, recite the alphabet and read a short book, but he still couldn’t tell which square was purple in Candy Land. Colour-blindness runs in my family, and a trip to the optometrist confirmed it: Bode was colour-blind too.

Colour-blindness is not actually a type of blindness but an inability to see certain colours accurately. (It is also called colour vision deficiency.) It happens when our retinas don’t detect light properly. The actual colours a colour-blind child has trouble seeing depend on what part of the retina is affected, but most commonly, he will have trouble perceiving anything with red or green pigmentation. (These children can see blue and yellow hues fine.)

Most cases of colour-blindness are genetic. The condition typically skips a generation, is carried on the mother’s side and shows up mostly in boys. In my case, my father was colour-blind; I was the carrier and both my sons are colour-blind—but my daughter isn’t. Colour-blindness is rare in girls and most common in Caucasian males: According to a 2014 study published in Ophthalmology, one in 20 Caucasian boys is colour-blind.

If your toddler is having trouble identifying colours, don’t panic—not all kids learn this skill at the same age. But if he’s consistently mixing up hues like red, green, purple and orange, you should see an optometrist.

In fact, Toronto-based optometrist Kalyn Burroughs recommends all children have an eye exam before they start kindergarten and says testing for colour-blindness is a regular part of the appointment. If your kid is identified as colour-blind, more detailed tests will be done at a later age to determine the severity. Depending on the extent of the colour-blindness, your kid could be restricted from choosing certain careers, such as fighter pilot, police officer and firefighter.

In our family’s experience, other than a few mismatched outfits and trouble with games that involve colour (like Candy Land), colour-blindness doesn’t have a large impact on a kid’s everyday life.

At school, however, your child could have trouble with things like patterning, colour pie charts and, when he gets older, science class litmus tests. “If teachers are made aware of colour-blindness, they can offer alternatives,” says Burroughs.

A version of the article appeared in our September 2015 issue with the headline "Untrue colours," p. 32.

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