<unk>  is a medical condition in which the eyelid (usually the lower lid) folds inward. It is very uncomfortable, as the eyelashes continuously rub against the cornea causing irritation.<unk>  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.<unk>  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<unk>  occurs in both eyes, this is known as "bilateral<unk> ". Repeated cases of trachoma infection may cause scarring of the inner eyelid, which may cause<unk> . In human cases, this condition is most common to people over 60 years of age.
Entropion
Ectropion
Methylphenidate
Hydroxybupropion
Atomoxetine
Bupropion
Guanfacine
Mipomersen