Tigger said:
Interesting, thanks Shrimp, you have first hand knowledge of this? The article does state that the glasses hamper other areas of colour perception after the headline. To me it seems like this 'accident' contributed to a refinement of subtle red green perception, not that it cured anything. It peaked my interest as one of my good buddies and his brother are colour blind and are looking at this to help them.
I'm an optometrist, so among my studies I've taken a course in colour perception. By now, I've seen thousands of patients with colour vision defects and diagnosed hundreds of those (the rest had been previously diagnosed).
I'll try to explain it all in simple terms, though I'm not sure how simple I can make it. Normal human colour perception of the visual spectrum involves three colour vision pigments in the retina. In simple terms, they can be considered the pigments for the detection of short, medium and long wavelength light. Short wavelengths are blue, medium wavelengths are green, long wavelengths are red. People with colour vision defects are either entirely lacking or partially lacking one of the three pigments. How does this affect their perception of colour? I wish I had a chalkboard to draw on to illustrate, but given that I don't, I don't know, maybe I can sort of draw here. Consider normal colour perception to be represented by a triangle. All the colours of the visual spectrum can be represented by a point anywhere within that triangle. The points of the triangle represent the three colour vision pigments, which I'll call B, G, and R. Here's a X-Y axis to try to represent what I'm saying, with B on the traditional negative side, G on the Y axis, and R on the traditional positive side:
G
|
| 1
|
|
|
| 23 4
|
|
B--------------------------------------------------------------------R
How we perceive colours depends on where the colour falls within the triangle, basically representing how much that wavelength of light stimulates each of the colour vision pigments, so by it's position along the -X axis, the +X axis, and the Y-axis. Colours 1, 2, 3 and 4 will all look different to somebody with normal colour perception, although 2 and 3 will appear similar. Now, somebody who is entirely deficient in the G pigment will see no difference between colours 1 and 2, as they fall equally far along the X-axis, and it doesn't matter in the least where they fall on the Y-axis. Those colours will appear obviously different to somebody with normal colour vision but very much the same to somebody who's G-deficient. Colour vision tests are designed to exploit this situation, where certain numbers are essentially invisible to colour vision deficients because of where their component colours fall in the spectrum.
When anybody (normal colour vision or not) looks through a tinted lens, it alters their perception of colours, and so too will these glasses. In the case of somebody who's colour vision deficient, when looking at a colour vision test, it will alter the perceived wavelength of the carefully designed and chosen colours too allow the distinction of what was designed to be invisible to the colour vision deficient. Say, it might make 2 look a little more like 3, so the invisible distinction between 1 and 2 might be skewed more to be like the distinction between 1 and 3, which is more detectable to the G-deficient. This isn't restoring colour vision; it doesn't grant the ability to make colour distinctions along the Y-axis, and it never can or will. If one is looking through blue-purple lenses, it will make everything look a lot more blue-purple. Yes, for the colour vision deficient, it can allow some more distinction between some shades that might otherwise appear identical. On the other hand, not only does it not provide any more richness of colour perception, it actually takes away from it. Try seeing how long you'd want to wear blue-purple lenses before you couldn't stand how skewed it makes all colours to looking blue-purple. That statement applies equally to colour vision deficient people.
To me, the "accident" part of the story is either an angle to try to pitch the supposed novelty (and it actually is nothing novel in the least) of the item, or perhaps it was something that was accidentally enough "discovered" by whoever is making this product in the same way that Columbus "discovered" America long, long after others had already done so. If your friend and his brother would desperately like to be able to conceivably "pass" a traditional colour vision test and it's worth the money to them to do have whatever experience that might be, then I suppose they can do it. But they should know that it really only helps them "pass" the test by actually changing the test, as it's effectively changing the carefully chosen colours (as they meet the eye) enough to see some colour distinctions better. At that point, they're not really passing the colour vision test, but rather a drastically altered version of the colour vision test, so it's pretty meaningless outside of a fleeting revelation of sorts, I suppose. Beyond that, it's just an expensive pair of glasses that makes everything look really blue-purple.
