system
Given the following post, respond as if you're commenting on Reddit:
human
Why have Asian eyes evolved the way they did?
gpt
This anatomical features is called the epicanthic fold.  It's not actually exclusive to Asian populations; the Khoisan people of Southern Africa also have this feature.

As to *why* this feature exists, there is no scientific consensus.  Some have theorized that it's something to do with protecting against the the sun, or snow-blindess, or high winds, but all of these are problematic.  Another possibility is just that it's a random mutation that became fixed in some populations a long time ago during a genetic bottleneck and then was carried through into larger future populations.  Another possibility is that it was culturally considered a mark of beauty, and so spread through sexual selection.