This is an Ishihara colour test plate. People with normal vision should see the number “74”. Many people who are color blind see it as “21”.
What we see and how we see it depends on how our brains and eyes work together. The eyes see the object we’re looking at, and it’s the brains job to perceive the rays of light to distinguish the colour. It does so by using photoreceptors, and those who have an abnormal makeup of the photoreceptors will see the world a little differently than the rest of us.
Optometrist at East London Optometry, Dr. Lisa Pray, explains how colour blindness works. “Cones are the photoreceptors in the retina that gives us colour vision. There are three types, and if you’re missing one of those cones, you’ll have a colour deficiency.”
There are three different types of colour blindness. Red-green deficiency, blue-yellow deficiency, and complete colour blindness.
Pray adds that men are affected the most by it, since it’s hereditary and red-green colour blindness is carried on the X chromosome. That means men only get one shot at a healthy X chromosome while women get a second chance.
The term “colour blindness” is slightly misleading, since 99% of those diagnosed are only colour deficient.
“I’m red-green colour blind, which means you’re missing red cones in your eyes. So I struggle with shades of red, orange, green, and even blue and purple”, says Owen Hunsburger, student at Western University.
He says a main challenge he faces is how the general public doesn’t have the right understanding as to what colour blindness entails.
“We don’t see in black and white. It really annoys us when you ask us ‘what colour is this?’ No one really realizes how reliant we are on colour for identifying things. You could tell me to look at the guy in the red shirt, but then I could be looking at the person in the brown shirt and I wouldn’t know the difference.”
There is no cure or procedure to rid of colour blindness, but some folks opt out for some specialty glasses that contain different colour tints on the lenses. These glasses help with registering a wider range of colours but the ultimate way to get over colour blindness is acceptance.