Does eye colour affect sight?

[Wallenstein]

Does a person’s eye colour affect their sight ability?

e.g. are the blue eyes of scandinavians better suited to their environment, or is that just a genetic fluke with only aesthetic appeal?

[CalMeacham]

As far as I know, it doesn’t. The iris is supposed to be opaque (or else there’s no point to it closing down, which is supposed to restrict the amount of light reaching the retina, something which has experimental confirmation). That said, I don’t know of anyone who’s actually looked into it. I would be very surprised if iris color had any function in vision.

its appeal may not be purely “aesthetic” – there might actually have sexual selection or survival value for some other reason. It’s certainly significant that you don’t find a lot of blue-eyed black people, and blue prevailing in northern regions.

[irishgirl]

Albino people do have poor eyesight, but this is because they lack the pigmentation on the retina- the back part of the eye- not because of the iris pigmentation.

[chrisk]

@CalMeacham

It’s certainly significant that you don’t find a lot of blue-eyed black people, and blue prevailing in northern regions.

Hmm… that would seem to indicate that there’s a high correlation between heavier pigmentation in the iris, and heavier pigmentation in the skin. Skin pigmentation, as I understand it, can select to the environment in various ways - affecting everything from skin cancer susceptibility to vitamin D production and resistance to exposure in hot/cold climates.

Do any of the genes for pigment production affect both the eyes and the skin, i wonder? Or are they all seperate factors that just happen to usually appear together?

[Bob55]

@chrisk

Hmm… that would seem to indicate that there’s a high correlation between heavier pigmentation in the iris, and heavier pigmentation in the skin. Skin pigmentation, as I understand it, can select to the environment in various ways - affecting everything from skin cancer susceptibility to vitamin D production and resistance to exposure in hot/cold climates.

Do any of the genes for pigment production affect both the eyes and the skin, i wonder? Or are they all seperate factors that just happen to usually appear together?

I think the eyes, skin, and hair are all the same pigment (melanin). This site says:

Melanin has been shown to be a powerful neutralizing agent for free radicals - molecules which are potentially harmful to the body. In the eye, it occurs in the retinal pigment epithelium - behind the retina - where its antioxidant properties reduces the risks of macular degeneration. People with more eye melanin have less occurrence of macular degeneration; people with less eye melanin have greater occurrence of macular degeneration.

Wikipedia says that “people with blue eyes are more at risk for sun-related eye problems”.

So I guess in the end it is an advantage to have darker eyes with regards to vision. But as previously mentioned, it may be a sexual selection - I know that it’s now thought that blond hair is selected because it was the only “visible” sexual symbol in the northern climates (because everyone was clothed) and even blond women tend to get darker hair with age. Therefore blond hair denoted “youthfulness” in a woman. I’ve heard that a lot of babies have lighter eyes and they get darker with age, I’m wondering if the blue eyes might be a similar selection for “youthfulness” as eyes are also visible even when fully clothed.

Another thing I’ve read said that blue eyes was a result of a single mutation at some point, and that person is the ancestor of all of those with blue eyes today. Or was that red hair…