|Simulated cause and effect of color blindness—Images courtesy EnChroma|
The photo on the left represents normal color vision, and the one on the right simulates the way things look to people with red-green color blindness. The charts shows how the gap between the green cones and red cones are narrowed in people with red-green color blindness.
|Normal and Deuteranoptic vision, courtesy Color-Blindness.com|
Another way to think of it is that for people with color blindness, the red and green signals are making noise on the same channel. It's like having two radio signals going at the same time. You can't make out what they're saying on either station, and red and green end up being mixed up. People with color blindness have the necessary healthy receptors. The only problem is that they're too close to each other.
To address this problem, engineers at EnChroma developed special filters which fine-tune the light going to each of those closely nested receptors. The result is a genuine experience of red, green, purple, and pink colors where they weren't visible before.
The promotional video (link to YouTube) shows the emotional effect of color-blind people trying on the glasses and seeing colors for the first time.
Because there are many kinds of color blindness, EnChroma is careful not to claim that this is a universal cure, but it appears to provide a helpful boost for many deutans. EnChroma/Valspar offers a free online color blindness test to see if they might be suitable.
Reviewers on Amazon say that the glasses sometimes take a while to get used to, and that you have to learn the names for unfamiliar colors. There are also concerns about the build quality and brittleness of the lenses.
Read EnChroma's more in-depth explanation
Color blindness test