Ptosis

Ptosis (from the Gr. piptō, 'I fall') signifies a drooping or falling of the upper eyelid, and arises from weakness of the muscle which elevates it, or from palsy of the third or motor oculi nerve. If it is congenital, or occurs without any apparent cause, and resists medical treatment, it may be removed by a surgical operation, by which the eyelid is brought under the action of the occipito-frontal muscle, which receives its nervous power from another source.