Depending on who you ask, colour blindness can affect as many as 5-8% of males and 0.5% of females. So with up to 1 in 12 males having the condition, I found it quite intriguing that not much was known by the general population.  In fact whenever I tell people I’m colour blind I still get the same questions “Can you see this colour?” or “What colour is this?”.


So instead of repeating myself over and over I thought why not look into the condition and explain it in as plain English as I can.

So what is colour blindness?

Colour blindness, (also known as Dyschromatopsia) or colour vision deficiency, is the inability to perceive differences between some or all colours that other people can distinguish. Pretty simple so far. Now let’s dig a little deeper:

Let’s have a look at the human retina (that’s the part at the back of your eye).

 

 

Inside this retina, there are 2 types of light sensitive cells. The rods (these are in the peripheral part of the retina) give us our night vision but cannot distinguish colour. And the cones (these are in the centre of the retina), which are no good at night, but allow us to perceive colour during daylight conditions.

The cones are the part which cause problem in colour blind or colour deficient people. There are 3 types of cones; sometimes referred to as red, green and blue receptors (this is not entirely accurate, but possibly the easiest way to describe them).

Here is a microscopic picture of the cones (it won’t help you to understand it, but I thought it was a cool pic):

 

 

So now let’s get down to the different types of colour blindness. There are many different types of colour blindness, but they can all be categorised into three basic groups:

Monochromacy:

This is also known as "total colour blindness". It is the lack of ability to distinguish any colour; this occurs when two or all three of the cone receptors are missing. This is an exceptionally rare form of colour blindness (thank goodness).

Dichromacy:

This is a moderately severe color vision defect in which one of the three basic colour mechanisms is absent or not functioning. It is hereditary and sex-linked, affecting predominantly males. Dichromacy occurs when one of the cone pigments is missing.

There are 3 types of Dichromacy:

• Protanopia - This is where there is a complete absence of the red cone or receptor. It is a form of colour blindness in which red appears dark.

• Deuteranopia – This is where there is a complete absence of the green cone or receptor. It is a form of colour blindness which moderately affects red-green hue discrimination.

• Tritanopia – This is an exceedingly rare colour vision disturbance in which there are only two cone pigments present and a total absence of blue cone or receptor.

Anomalous Trichromacy:

This is the more common type of colour vision deficiency and occurs when one of the three cone receptors are altered in their spectral sensitivity. This results in colour impairment, rather than loss.

There are 3 types of Anomalous Trichromacy:

• Protanomaly – This is a mild colour vision defect in which there is an altered spectral sensitivity of the red receptors. This results in poor red-green hue discrimination.

• Deuteranomaly – This is a mild colour vision defect in which there is an altered spectral sensitivity of the green receptors. This is the most common type of colour vision deficiency which mildly affects red-green hue discrimination.

• Tritanomaly – This is a rare colour vision defect in which there is an altered spectral sensitivity of the blue receptors. This results in blue-yellow hue discrimination.

Hopefully that explains the basics of colour blindness (and as simply as possible), now there are just two things left.

Firstly, the big question, which one am I? My type of colour blindness is Protanopia.

Secondly, being colour blind used to be considered a disability, but in reality there are some benefits. It is believed that colour blind people can actually distinguish camouflage better than normal colour vision people. I’m not entirely sure if that is true, but one thing I do know, being colour blind allows you to look at the world differently, something I do not take for granted. I hope this has helped you.