When Arsenal lined up before the game against Ludogorets on Tuesday night, people couldn’t understand why they were wearing their monstrous third kit instead of red and white.

Surely it had something to do with the sponsors/kit makers, we mused. They were forcing Arsenal to rotate their kits and play in the one that looks like something Chelsea threw up.

Not so it seems.

While red and white seems like it would have been far better in terms of contrast between the sides, that’s only the case of you aren’t one of the 1 in 12 men or 1 in 200 women who suffer from colour blindness.

The most common form of colour blindness involves red and green:

Anyone wondering about #LUDARS selection of kits – most common form of color blindness is red and green combination.

— Dejan Marolt (@dejanmarolt) November 1, 2016

While diseases such as diabetes and MS can cause colour blindness, the most common cause is genetic with it being inherited from the mother.

According to the site, colourblindnessawareness.org,

Most colour blind people are able to see things as clearly as other people but they unable to fully ‘see’ red, green or blue light. There are different types of colour blindness and there are extremely rare cases where people are unable to see any colour at all.

The most common form of colour blindness is known as red/green colour blindness and most colour blind people suffer from this.

Although 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. See the example of pink, purple and blue pen cases below to understand this effect.

So there you go.