Blepharospasm is an involuntary closure of the eyelids.
"Blepharo" refers to the eyelids, and "spasm" to involuntary muscle contraction. In blepharospasm, the eyelids close involuntarily due to an unknown cause within the brain. Blepharospasm is a form of dystonia, a disorder characterized by sustained muscle contraction. The most common form of blepharospasm is called "benign essential blepharospasm," meaning it is not life threatening and is not due to some other identifiable disorder. A condition called hemifacial spasm causes similar symptoms, but affects only one side of the face, and is caused by an irritation of the facial nerve outside of the brain.
Blepharospasm is estimated to affect approximately 15,000 people in the United States. Onset is most commonly between the ages of 40 and 60, but can begin in childhood or old age. Women are affected approximately twice as often as men.
The cause of benign essential blepharospasm is unknown. Evidence suggests it may be genetic in some cases, although genes have not been identified. A person with blepharospasm often has dystonia in another region of the body such as the mouth or the hands (i.e., writer's cramp). Other forms of dystonia or tremor may affect other family members. Blepharospasm is not caused by a problem with the eyes themselves, but rather with the brain regions controlling the muscles of the eyelids.
Secondary blepharospasm occurs due to some identifiable cause. The most-common cause of secondary blepharospasm is a reaction to antipsychotic medications, and is called tardive dystonia. Damage to the brain, either through stroke, multiple sclerosis, or trauma, may also cause blepharospasm.
Blepharospasm often begins with increased frequency of blinking, which may be accompanied by a feeling of irritation in the eyes or "dry eye." It progresses to intermittent, and then sustained, forceful closure of the eyelids. Symptoms are usually worse when the patient is tired, under stress, or exposed to bright light. Symptoms may become severe enough to interfere with activities of daily living, and can render the patient functionally blind.
Blepharospasm is diagnosed by a careful clinical exam. A detailed medical history is taken to determine exposure to drugs or other possible causative agents, and a family history is used to determine if other family members are affected by other forms of dystonia or tremor.
The treatment team consists of a neurologist and possibly a neurosurgeon.
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Author Info: Richard Robinson, The Gale Group Inc., Gale, Detroit, Gale Encyclopedia of Neurological Disorders, 2005 |