VIA| In this video, a color blind man called Ethan is given what looks like a pair of sunglasses by his friend. After trying to work out what’s so special about them, he suddenly looks around and realises that he’s seeing the world in colour for the first time, which leads to a whole lot of emotional freaking out: “Is this purple? What the f*ck! … It’s so beautiful.”
The glasses are called EnChroma, and they’ve been developed to help people with colour blindness see the world more vividly. To understand how they work, you first need to understand that colour blindness isn’t a type of blindness at all. In fact, colour doesn’t actually exist outside of our brains. “It doesn’t mean that I see the world in black and white,” Ethan explains in the video above. “It just means that I see things in a way that are a little bit more dull than usual. I can see some pink and some green, it’s just sometimes green looks brown or yellow, and pink looks silver or blue.”
This is because of the balance of photopigments in the cone cells of Ethan’s retina. Basically, our retinas are made up of cone and rod cells. The rod cells are the ones that detect light, and the cone cells detect colour. When someone with perfect colour vision looks at an object, the different wavelengths of light hit their retinas and are absorbed by specific photopigments found inside their cone cells.
There are normally three classes of cone cells, each primed to absorb red, green or blue wavelengths of light. And when this happens, the photopigments undergo a chemical transformation that causes the cone cell to fire a nerve impulse, which is carried by the optic nerve to the brain. This allows us to ‘see’ the colour.
There are lots of different types of colour blindness, but people who are colour blind have an imbalance or an overlap in the types of photopigment in their cone cells. So for example, the cone cells that are supposed to detect red light may absorb too much green, or vice versa. This means that it’s harder for them to differentiate certain colours, and they may see them in a different way.
The EnChroma glasses fix this by using a mathematically designed lens to pre-filter these wavelengths of light, and make sure that when they hit the cone cells, they’re absorbed in the same ways as normally functioning cone cells. It’s like they actually warp the light in advance, to make sure it’ll hit the cone cells of people with colour blindness in the same ways as it would normal eyes.
Which is why it’s so exciting for Ethan when he puts them on and realises that he can suddenly see colours that he previously couldn’t, like that damned purple. We dare you to watch the video and not smile. Science, you’re pretty incredible.
Find out more about how we perceive colours in the Vsauce episode below: