Before we get down to the structure of the eyes, I would like to mention that double eyelids are a predominantly Caucasian phenotype. Most Caucasians I've seen on my trip to Queensland (a very enjoyable trip from Gold Coast up to the Whitsundays) had double eyelids. However only about 50% of Asians have double eyelids.
NB: I wish to address that the connotation of single eyelids is a misnomer: everyone has double eyelids, except in some cases, the crease, or fold, is so low (and close) to the lash line that it's not noticably visible.In my sourcing for the article, I've found a very good site that explains the
anatomy of the Asian eyelid, but I will attempt to summarize the gist of it here.
The important components of the eyelids for the sake of this discussion are
1) Levator Aponeurosis
2) Tarsal Plate
3) Skin of the Eyelid &
4) Fat, fat and more fat.Levator Aponeurosis: A muscles that lifts the eyelids. Its different site of attachment in the Asian eyelid is what causes the single eyelid.
Tarsal Plate: It's just below your eyelash line and it gives some rigidity and structure to the lash line (you can pinch your lashes to feel it).
Skin: What makes up the external surface of the eyelid, it forms the creases and folds when we open our eyes.
Fat: Strategic locationing (and surpluses) of fat gives the "bulgy" Asian eye appearance (especially pronounced in the lower eyelid, a.k.a. eyebags), making us look wary and tired all the time. Caucasians (most) have relatively thinner eyelids.
In a nutshell, some Asians (me included) don't get double eyelids cause a muscle attaches to a different spot (see that red arrow?). It's as simple as that.
