Non-Asian Eyes vs. Asian Eyes
Asian mono-eyelids lack a connection from the skin to the underlying eye-elevating muscle. This connection is what creates a supratarsal fold or double eyelid crease. Asian eyelids also tend to be thicker due to the increased amount of skin, superficial muscle (orbicularis muscle), and fat deposition. Furthermore, the eye-elevating muscle (levator) is also smaller. This smaller dimension of the Asian eye’s levator muscle also has a decreased efficiency in the excursion of eyelid elevation, which causes Asians to have higher incidence of ptosis (see Ptosis). Generally, people with larger eyes tend to have more powerful eye-elevating muscle function and less incidence of ptosis.
In Asians who have existing natural folds, the connection is more of a singular layer than a multi-layer as found in non-Asian eyes.
This singular layer connection occurs mainly at the site of the crease, whereas for non-Asians it extends from the visible crease all the way down to the lash line. This multilayer of connections present in non-Asian eyes is what provides a more distributed force throughout the eyelid. Therefore, because of this singular connection, even natural Asian eyelid folds tend to be weaker and prone to loosening with age.
Epicanthal fold, or Mongolian fold, is the excess medial skin and fibrous banding that covers the nasal inner corner (canthus) of the eye. The presence of an epicanthal fold is prominent among Asians (see The Ideal Shape and Dimension). The banding prevents the corner of the inner eye to close completely, thus creating an inner fold. Epicanthal fold will make the eyes appear farther apart. It can also cause the nasal bridge to appear flatter and wider.
LOWER EYELID FEATURE
Asians also have a unique lower eyelid feature of fullness immediately below the edge of the lower lash line. Referred to as “aegyo-sal” in Korean, this feature is present due to the hypertrophic orbicularis muscle in the lower eyelid. Due to the thicker orbicularis muscle among Asians, this feature is much more evident in Asian eyes than non-Asian eyes. This is a desired feature by many Asian women as its presence is associated with youthfulness and friendliness.