What is "entropion"

Entropion \En*tro"pi*on\, n. [NL.] (Med.) Same as Entropium. [1913 Webster] ||

n. (context pathology English) An inversion (turning inward) of the margin of the eyelid

Entropion is a medical condition in which the eyelid (usually the lower lid) folds inward. It is very uncomfortable, as the eyelashes constantly rub against the cornea and irritate it. Entropion is usually caused by genetic factors. This is different from when an extra fold of skin on the lower eyelid causes lashes to turn in towards the eye ( epiblepharon). In epiblepharons, the eyelid margin itself is in the correct position, but the extra fold of skin causes the lashes to be misdirected. Entropion can also create secondary pain of the eye (leading to self trauma, scarring of the eyelid, or nerve damage). The upper or lower eyelid can be involved, and one or both eyes may be affected. When entropion occurs in both eyes, this is known as "bilateral entropion." Repeated cases of trachoma infection may cause scarring of the inner eyelid, which may cause entropion. In human cases, this condition is most common to people over 60 years of age.