Blepharospasm is a muscle disorder characterized by involuntary spasm of the muscle around the eye, resulting in uncontrolled narrowing or closing of the eyelid. One serious consequence is impairment of vision. In some patients, forced closure of the eyelid becomes so severe that doing simple things such as driving a car or using a computer becomes a challenge.

Approximately 65% of people with blepharospasm are female, and the average onset age is 56 years. In the early stages of blepharospasm, patients may complain of irritation or discomfort of the eyelids as well as increased eye blinking. As blepharospasm progresses, blinking usually becomes more frequent, forceful, or uncontrollable. Bright light, noise, stress, polluted air, or wind can make the symptoms worse.