Around one in 12 men and one in 200 women are "red-green" colour blind, which makes it difficult for them to distinguish between different shades of red, yellow and green. They may also see colours as much duller than they would appear to someone with normal colour vision, and could find it difficult to see shades of purple, or red type on black backgrounds. Most people who are colourblind don't notice in their daily lives, and the only real impact is that they can't do things like fly commercial airlines or work in paint factories - although it can be quite an emotional experience finding out that you do have the condition, as this scene in Little Miss Sunshine highlights.
One company, Enchroma, has created sunglasses which mitigate this condition: they're designed to allow wearers to perceive more colour than they are usually able to see. Last year we got two people to test out two pairs of Enchroma glasses and after a year of wearing them, we can report that they really do work. They consistently allow colourblind people to experience vibrant colour even more deeply than they would be able to without them. Especially for the first few weeks, they really take your breath away if you're looking at a dramatic sunset. You do eventually get used to the effect, but there's a reason why they've been this writer's main pair of sunglasses ever since I first wore them. If you're interested, make sure you check out the website thoroughly and find out what type of colourblindness you have, because some types don't work with the glasses. And consider that there are expensive custom charges to pay if you live in the UK. But they're definitely worth the investment.
Watch our Facebook Live video to see the reaction of two colourblind men putting on the glasses for the first time.
More about colourblindness
The technical term for the condition is "colour vision deficiency" and relates to people who have a problem with the colour sensitive cells in their eyes. It's a problem that mainly affects men because the genetic fault is linked to the X-chromosome.
The Enchroma range of glasses claims to "alleviate red-green colour blindness, enhancing colours without the compromise of colour accuracy." Videos on the internet show colour blind people trying on the glasses during sunset or in garden centres and expressing shock at seeing vibrant colours where they were previously dull or non-existent.