Blepharospasm of one eyelid is often associated with fatigue or stress.
Blepharospasm affecting all four eyelids is thought to be due to abnormal functioning of the basal ganglia which are situated at the base of the brain. The basal ganglia play a role in all coordinated movement. We do not fully understand what goes wrong within the basal ganglia to cause this type of blepharospasm. In most people blepharospasm develops spontaneously with no known precipitating factor. The most frequently affected population are females between 40 and 60 years of age.
Blepharospasm can occur with other abnormal facial movements. In such cases, spasms of the eyelids are accompanied by jaw clenching or mouth opening, grimacing, and tongue protrusion.
Blepharospasm can be induced by drugs, such as those used to treat Parkinson’s disease.