ptosis
Meaning of ptosis: Ptosis is a drooping of the upper eyelid that can be present from birth or develop later from nerve, muscle, or structural causes.
Definition of ptosis
Ptosis is drooping of the upper eyelid, which can partially or, in more severe cases, substantially cover the pupil. It can be present at birth, when it usually reflects an issue with development of the muscle that raises the eyelid, or it can develop later in life from a range of causes.
Acquired ptosis can result from age-related stretching or weakening of the eyelid muscle and its attachments, from a problem with the nerve that controls the muscle, from certain muscle disorders, or from a mass or injury affecting the eyelid or the structures around the eye. The degree of ptosis can range from mild, with little effect on vision, to severe enough to obstruct part of the visual field.
Because ptosis has many possible causes, evaluation typically considers whether it affects one eye or both, whether it developed suddenly or gradually, and whether other neurologic or muscular symptoms accompany it.
Used in a sentence
The examination noted mild ptosis of the left upper eyelid that had reportedly developed gradually over several years.
Good to know
Sudden-onset ptosis, particularly when accompanied by other neurologic symptoms, is evaluated differently from gradual, age-related ptosis, since a sudden change can point to a nerve or muscle disorder requiring prompt assessment.
Word origin
Where “ptosis” comes from
From Greek ptosis, meaning "a falling," from piptein, meaning "to fall."