Why do caucasian people have natural double eyelids while most east asians don't?

Question

Why do caucasian people have natural double eyelids while most east asians don't?

Answer 1

Very very interesting question. Thank you for asking it. It made me do a bit of thinking and some research.  

The scientific theory is that slanted eyes among Asians in the Far East is because they have more fat on their eyelids as a protection from extreme cold climates. The epicanthic fold is supposed to screen harsh sunlight in a snowy environment. Slanted eyes are not unique to the Chinese, Japanese etc.  Laplanders and Eskimos have similarly slanty eyes.

This theory does not hold, however in the case of the Scandinavians who have round eyes even if they  live in similar climate conditions as the Chinese.     The explanation offered is that the Vikings took many women on the basis of their beauty and the standard was round eyes.  

My additional contribution to the above is that I think that cultures which are very unified (Chinese, Japanese, Koreans, for example) have been unable to marry off their children to grooms from other races who have  round eyes.  Thus, the eye shape of the Chinese, etc has hardly been  genetically altered through intermarriage.  

But things are changing. There is now a huge demand for cosmetic surgery to change slanted eyes to round eyes.  In as much as the shape of the eyes is only a matter of aesthetics,  it is also likely that there will be less slanty eyes in the future as people begin to take control of how they want to look like. By this, I do not mean to insult people with slant eyes--I think these eyes are beautiful and like round eyes, their beauty will be judged on a holistic perspective that includes inner charm and grace.

;-)

Answer 2

i think the relation to the sun has something to do with all our traits like dark skin people are nearer the equator and the eye thing has to do maybe with sun or dust in whatever area u are from the more lid the more protection u need

Answer 3

Genetics.

Answer 4

its the genes... same reason why swedish people have natural blonde haircolor. When humans migrated from africa like 20,000 years ago or so, groups of people spread out. Lets  say a group of families that had smaller eyes moved to asia. Well as they reproduced, they shared the dominant eye gene and therefore passed onto kids and so on.