1. Spasm of the eyelid muscle resulting in the closure of the eye or eyes.
2. The involuntary forcible closure of the eyelids.

The first symptom may be uncontrollable blinking. Only one eye may be affected initially, but eventually both eyes are usually involved.

The spasms may leave the eyelids completely closed causing functional blindness even though the eyes and vision are normal.

Blepharospasm is a form of focal dystonia (a condition of either excessive or inadequate muscle tone).