too bright or halo-ing solved by blue coated glasses?

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youtube: How To Reduce Eye Strain Using Blue Cut Glasses (SeeCoat / Prevencia / Irlen)

This guy's saying that he is tetrachromatic and has a sensitivity to blue light. An estimated 8% of men and 15% of women have this. And when outside, his pupils used to be tightly constricted. For him, objects and even people sometimes had a halo-ing effect.

Blue-cut lenses bounced back the high-end blue (almost ultraviolet) and thus help a lot. His pupils weren't then so tightly constricted and thus the world seemed brighter and more colorful. It even seemed to lift his mood a little.

Also helped with back-lit LED screens.

This has been around for a while and probably price has come down (although probably not enough!). Each company seems to give a unique name to their blue lenses, yes, to make it sound like they're selling something unique.

A male with XY chromosomes can't be a tetrachromat unless he has some form of Klinefelter's Syndrome (XXY), because the genes for cones (the cells which allow the light to detect color) are only on the X chromosome and chromosome 7. Typically, the X chromosome will carry genes for two different cones, which detect light in two different ranges...long wavelength(L) and medium wavelength(M), and chromosome 7 carries the gene for short wavelength(S). The S cone is most sensitive to light around 445nm. This is the color light blue. The M cone is most sensitive to light around 508nm. This is blue green. And the L cone is most sensitive to light around 565nm. This is yellow green. However these cones are often thought of as "Blue, green, red" cones, and indeed the L cone is what allows us to perceive red, even though though it's peak sensitivity is not in the red range of light. These cones working together is what allows us to perceive the color spectrum in the manner that we do. People with normal color vision perceive the spectrum as seven main colors, red, orange, yellow, green, blue, indigo and violet, with transitions in between.

However, due to genetic variation, there are different variants of the genes for each type of cone. For example, one person's L cone may indeed be most sensitive to light at the 565nm wavelength, and another person's L cone may be most sensitive to light at the 569nm wavelength.

People who are red green colorblind (or color deficient, as optometrists like to call it), instead of receiving an X chromosome with genes for L and M, receive an X chromosome with the following gene configuration.

M
L
M1, M1
L1, L1
M1, M2
L1, L2

Where the 1 and 2 signify different variants of a gene.

Because males inherit their X chromosome from their mother, the mother will also have an X chromosome with any of the above configurations. Provided her other X chromosome is normal, these are the cones she will have...

From the normal X chromosome and chromosome 7.
Lx, Mx, Sx where little x represents some unspecified variant.

From the abnormal X chromosome and normal chromosome 7.
M1, M2, Sx

or

L1, L2, Sx

In total, instead of the normal...
Lx, Lx, Mx, Mx, Sx, Sx where x can represent the same or different variants.

She will have....
Lx, Mx, M1, M2, Sx, Sx

or

Lx, L1, L2, Mx, Sx, Sx

If Mx, M1 and M2 or Lx, L1 and L2 are significantly different enough variants from each other, she will have four peaks of color sensitivity instead of 3, and this could enable her to perceive more than the 7 main colors that trichromats do.

You might say, "well wait a minute, if we are both trichromats but you have L1 and I have L2 and they are significantly different enough from each other, is it possible that I can see colors that you can't, and you can see colors that I can't?" The answer to that is yes!, but we still each discern that the color spectrum has 7 main colors. Tetrachromats would see more than 7 main colors.

The shorter wavelengths have the higher energy. Blue light is more energy intense than the other colors in the visible spectrum. And invisible ultra violet packs even more punch in its photons. That much is true.


So the blue end of the spectrum is harder on everyone's eyes regardless of whether you have the syndrome or not.

And that's why they invented "blue blocker" sunglasses, that were originally hawked on late night TV infomercials, and now are seen in stores.

Blue blockers were revolutionary (or supposed to be) because they block out the blue and ultraviolet light. But let other colors in. So you get less eyestrain then conventional sunglasses, but actually see better and brighter. Mainly for drivers.

And I liked Blue Blockers the few times Ive worn them. Not a big connieseur of sunglasses but I would say that Blue Blockers do seem to be better than other sunglasses.

So blue blockers would already do what that guy is talking about. But here is the thing. Blue Blocker sunglasses are NOT tinted blue. The opposite. They are dark amber color (brownish orange).

So I am confused as to how doing opposite things could solve the same problem in this case.