This sounded odd to me the first time I
heard it. Having a "double" eyelid fold is considered
attractive in Korea these days. So, many girls have
surgery to create one. One friend told us that the surgery
is a common high school graduation gift. (I suppose it's
no weirder than getting one's ears pierced.)
After I heard about this, I started looking for the
difference. After a couple awkward moments on the metro, I
decided the difference is just too subtle for me to see
consistently. I believe the woman on the left has the
sought after extra fold, while the woman on the right does not.