Are you colour blind?

By October 31, 2016Eye Health

If you’re a sporting fan, you’ll be very familiar with the term “colour blindness”, after all how many referees suffer from this very serious condition! There is a common belief that if you are colour blind, you can only see everything in black and white, and a bit of grey in between. Well, there’s good news and bad when it comes to busting this myth rgss202j.dll. The good news, is that even if you are colour blind, you are most often still able to see colour which means the bad news is that doing a Rubik’s cube will still be impossible!

How you see colour
When light hits an object, the object absorbs some of the light and reflects the rest of it. The wavelengths reflected back off the object determine the colour you see. Take a minute to think back to your school days when you learnt about rods and cones. Both rods and cones sit in the retina, the light sensitive area at the back of your eye. Rods see in black, white, and shades of grey and tell us the form or shape that something has. Cones are what allows you to see in bright colour. You have around 6-7 million cones, concentrated on a 0.3mm spot in your eye! Not all cones are alike. Most respond strongly to red light, while about a third are set off the most by green light. Another lot respond strongest to blue light

When the light reflected back from an object hits these cones, it stimulates them to varying degrees. The resulting signal is zapped along the optic nerve to the visual cortex of the brain, which processes the information and returns with ta daaaa…. a colour.

What it means to be “colour blind”
Colour-blindness, more appropriately called colour vision deficiency, is a term used to describe a group of around 8 conditions that affect the way people see colour. This is caused from the malfunction of one, or all, of the three cone cells. For the majority of those with the condition, they struggle with distinguishing between certain shades, rather than not seeing any colour at all. It is extremely rare for someone to literally only see black and white.

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The most common form of colour blindness is known as red/green colour blindness. This does not mean sufferers mix up red and green, it means they mix up all colours which have some red or green as part of the whole colour. For example, a red/green colour blind person will confuse a blue and a purple because they can’t ‘see’ the red element of the colour purple.

Blame your colour chromosomes!
While it is possible to acquire colour vision deficiency, from aging, alcohol, some medications or even a serious knock on your head, it is in most cases a genetic condition based on a few corrupted chromosomes. The condition is a lot more common in men, affecting around 8%, and only half a percent of women. So, ladies, give your man a break when he can’t help you choose between the two shades of purple… they DO look the same, he might not be making it up!

The effects of colour vision deficiency can be mild, moderate or severe. For example, around 40% of colour blind pupils currently leaving school are unaware that they are colour blind! The best way to find out whether you have colour vision deficiency is a check-up with your optometrist. There are many tests available to test colour vision and to accurately determine which type you may (or may not!) have.

Can it be treated?
Unfortunately, there is no known cure for genetic causes of colour deficiency, but there are a few ways to help those with the condition distinguish colours more easily. One of these ways is to use special colour-filtering lenses. The way these lenses work is to correct the balance of the signals sent from an object to your three sets of cones. In this way, the lenses filter through the correct amount of light to stimulate the cones as they would be in someone with “normal” vision. For acquired colour vision deficiency, once the cause has been established and treated, your vision may return to normal.

So, it seems that having this condition isn’t quite as black and white as you may have thought. In fact, it gives a whole new meaning to seeing the world through rose-tinted glasses!