ELI5: How are colourblind people able to recognize the colours when they put on the special glasses, they have never seen those colours, right?

Read the Story

Show Top Comments

Others have already explained this very well. I want to point out that they are not able to recognize the colors. They can now distinguish between colors that they were unable to before. They do have to learn what they are, however. My friend got these glasses, and there was a beautiful sunset as we were driving home from an amusement park. She kept commenting on the colors, and calling them by the wrong names. She also is a retro gamer, and there was a game where she said, “It’s so much easier to play this now that I can see the bullets.”


I’m colorblind. I think the technical term is red-green deficient. I didn’t find out until I went to MEPs to join the military as a 19 year old. They administered the Ishihara Test and I failed it miserably. I can pass the alternative Farnsworth test and see my individual colors. I guess where it gets tricky for someone like me is certain shades blend together? I tried out some color blind glasses and what immediately stood out to me was how much more vibrant the colors were. Particularly green and purple. The trees, grass and flowers in the garden really “popped.” Having said that, I didn’t see a color I’ve never seen before, they just looked prettier than I’d ever seen before.


**Background** To humans, all colors are merely a combination of red (R), green (G) and blue (B). We have cells in our eyes (called cones) that compare intensities of RGB. Why RGB? The colors R,G, and B are spaced distinctly far apart on the color spectrum. And the more distinct and farther apart the cones are on the color spectrum, the wider range of colors we can see, and the more precisely we can tell them apart. **Explanation** These glasses only work for a **specific kind of colorblindness** where the green cones mutate to become more sensitive to the neighborhood of red, orange and yellow light and less sensitive to green. So now when red light comes in, the brain still gets an signal from the green cone, which is wrong. Also, when green light comes in, the green cones, which the brain usually expects to turn on, don’t. This overlap of sensitivity between mutated green cones and red makes it hard to tell colors between red and green apart. These glasses help by blocking wavelengths of light between red and green, thus exaggerating the difference such that the mutated green cones can function a bit more like normal green cones. With this comparison ability somewhat restored, the “color-blind” can better discriminate in that otherwise problematic area of red through green.


From someone who has protanomalous colorblindness, your assumption is correct. We’ve never seen the colors before and can’t reasonably talk about what they are. When I put my enchroma glasses on I’m seeing literally a different world than I normally do. It’s the reason that you see a lot of emotional videos where people start crying. It’s overwhelming to see the “real” world that we miss out on every day, how vivid and beautiful it is. Having protanomaly means I’ve never seen the color purple with my own rods and cones in the natural world. My eyes cannot physically process that wavelength. The glasses bend the light coming in to give my brain an imitated sense of seeing purple and the proper shades of loads of other colors as well. It really is a thing of beauty.


In addition to what’s been said, most of those ‘reveal’ videos are fake. The glasses kit itself will tell you about the importance of conditioning your eyes by wearing the glasses casually for a few hours a day, for a few weeks. I’ve known half a dozen people that tried them; they only worked for two of them, and neither of those people had a “Put it on and start crying” moment.