Spasmodic contraction of the orbicularis oculi muscle causes excessive blinking and involuntary eye closure. It can often be accompanied by ocular foreign-body sensation and be ameliorated by distracting maneuvers, and is worse at rest or in bright light. There may be involuntary clonic eye closure, tonic narrowing of the palpebral fissure, or difficulty opening the eyes. Blepharospasm may be so severe as to leave the patient no useful vision.