The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision.

A set of specialized hairs known as lashes grow from the upper and lower eyelid margins to further protect the eye from dust and debris.

The eyelid is made up of several layers; from superficial to deep, these are: skin, subcutaneous tissue, orbicularis oculi, orbital septum and tarsal plates, and palpebral conjunctiva.

The eyelids close or blink voluntarily and involuntarily to protect the eye from foreign bodies, and keep the surface of the cornea moist.

Eyelid surgeries are overall safe procedures but they carry certain risks since the area on which the operation is performed is so close to the eye.

[8] The upper eyelid crease is a common variation between people of White and East Asian ethnicities.

[9] However, East Asian eyelids are divided into three types – single, low, and double – based on the presence or position of the lid crease.

[12] In some individuals, an eyelid with excessive skin may push the eyelashes downwards and into the eye, obstructing vision in the case of long and thick lashes, and potentially causing corneal abrasion.

[13] Blepharoplasty is a cosmetic surgical procedure performed to correct deformities and improve or modify the appearance of the eyelids.

[17] East Asian blepharoplasty, or "double eyelid surgery", has been reported to be the most common aesthetic procedure in Taiwan and South Korea.

[19] A procedure to remove the epicanthal fold (i.e. an epicanthoplasty) is often performed in conjunction with an East Asian blepharoplasty.