asian eyelids:

there is a plastic surgery procedure to add a crease to the single eyelid that is typical in many asian people to create a double eyelid similar to what most non-asians have. it is actually kind of popular. and some people use non-surgical methods to create the "western" eye fold look. asian eyelid skin is thicker and has more fat and this is a reason there is no fold.

this is different from the epicanthic fold which is "a prolongation of a fold of the skin of the upper eyelid over the inner angle of the eye". the epicanthic fold is what makes the asian eyes look like they slant upwards. there is surgery to remove this too.

one explanation for the different eyelids is that "narrow eyes of asians are better suited for survival in windy, flat environments (like central-asian deserts or tundra)".

just to note, i do not support this surgery and i also think it is demented. i think people should not alter their natural appearances. i was just researching asian eyelids and came upon this info. again, this is for information purposes only. i do not support plastic surgery or altering one's natural appearance.