posted on Oct, 3 2010 @ 03:02 PM
It is because of melanin - this is what makes up our pigmentation. The darker our skin/eyes/hair are, the more melanin we have. Melanin is our natural
defense against too much sunlight. For this reason, people who are closer to the equator get more sunlight, so their skin/eyes/hair protects against
the sunlight by increasing the amount of melanin so that less UV and the such gets in. (Related, this is the reason we tan - more melanin is produced
when we are in the sun for a long time.) On the opposite end of the spectrum are those who live further north/south (closer to the poles); there is
very little sunlight there, so they need as much of it as they can get! So, they have less protection, ie less melanin and less pigmentation.
So, the reason that white people would have more red eye is because there is less melanin making up the pigment in their eye, meaning that the light
from the camera would reflect off the blood vessels easier.
However, red eye can still occur on people with skin color. Check out this kid:
No, he isn't black, but he's not white either and he's got red eye.
And this woman:
She looks like she's from India.
My theory is that red eye can happen to anyone under the right set of circumstances, but that it happens to white people more because they have less
pigmentation between the camera and the blood vessels behind their eye.