Do you see what I see?

Hello, hello. Welcome back to my wonderful world of colour.

Or in this case, perhaps not?

I just took this test here.

Luckily for me, I am part of the 94.5% of New Zealand‘s population that doesn’t exhibit signs of colour blindness.
I am one of the lucky 259 women who can identify a blue hue from a purple one, the 260th woman might see them both as blue. For men, colour blindness is much more common with 1 in 12. 

And when I say luck, for the majority of cases, being colour blind is almost a luck of the draw.

You see, colour blindness is a genetic mutation passed down from your parents.
The affected gene is carried on the X chromosome.
Women carry two X chromosomes (XX).
Men carry one X and one Y chromosome (XY).

You get one sex chromosome from your mum (it’s going to be an X, that’s all she has).
You get your second sex chromosome from your dad (it could be X, making you a girl orrrr it could be Y, making you a boy). 

The genetic family tree below shows the potential offspring of a non colour blind female who carries the mutated gene on one of her X chromosomes AND a non colour blind male.

genepool.png

Both X chromosomes must carry the affected gene for a girl to be colour blind meaning her father MUST be colour blind.  Only having one affected X chromosome will result in that girl being a carrier and she may or may not pass on that X affected X chromosome to her own children. 

Colour blind men can only pass on affected X chromosomes to their daughters, as boys get their Y chromosome from their father. 

Naturally speaking, nobody can determine whether you will be a boy or a girl.
Nobody can determine whether you get your mum’s dud X gene carrying the colour-blindness genetic mutation or you get her other one.
So the way I see it, it all comes down to luck.

As I mentioned in my last blog, two clever guys by the names of Thomas Young and Hermann von Helmholtz came up with the trichromatic theory of vision involving colour receptors. You can read all about it here. 

cones

Our red, green & blue cone photoreceptors! 

At the back of the human eye, there are cone photoreceptors and rod photoreceptors. For the majority of cases, it is faults within the cone photoreceptor cells which lead to differences in the way a person might see colours.

Colours through normal vision (when all three cones are in good working order) generally look a little something like this….

colourblindew
However, have a browse through my table and have a look at how the different kinds of colour blindness affect the way in which these colours are seen. 

table

For people who are colour blind, some tasks in life can be made pretty tricky. This includes, but is not limited to, interpreting traffic light signals or coloured charts, or as simple a task as picking ripe fruit and veges at the supermarket. 

Unfortunately, there is no cure. However, it’s not all bad news. Modern technology advancements have contributed to helping out our colour blind pals. Apps have been created to help coordinate colours specifically for those trying to find an outfit that doesn’t clash. Some apps allow for a photo to be taken and all of the colours within that photo are then able to be identified with a simple tap of the finger. 

Also, technology in the optical world has now made colour-correcting glasses for people with red-green colour blindness that look exactly like any other pair of glasses. Which is pretty damn cool.

So next time you’re picking out those bananas at the supermarket and you can easily tell which ones are ripe and which are not, be grateful that you aren’t in that small, unlucky 5.5% of New Zealand’s population. 

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