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Blepharo means "eyelid". Spasm means "uncontrolled
muscle contraction". The term blepharospasm ['blef-a-ro-spaz-m] can be
applied to any abnormal blinking or eyelid tic or twitch resulting from any
cause, ranging from dry eyes to Tourette's syndrome to tardive dyskinesia.
The blepharospasm referred to here is officially called benign essential
blepharospasm (BEB) to distinguish it from the less serious secondary
blinking disorders. "Benign" indicates the condition is not life
threatening, and "essential" is a medical term meaning "of unknown cause".
It is both a cranial and a focal dystonia. Cranial refers to the head and
focal indicates confinement to one part. The word dystonia describes
abnormal involuntary sustained muscle contractions and spasms. Patients with
blepharospasm have normal eyes. The visual disturbance is due solely to the
forced closure of the eyelids.
Blepharospasm should not be confused with:
o Ptosis - drooping of the eyelids caused by weakness or paralysis of a
levator muscle of the upper eyelid
o Blepharitis - an inflammatory condition of the lids due to infection or
allergies
o Hemifacial spasm - a non-dystonic condition involving various muscles on
one side of the face, often including the eyelid, and caused by irritation
of the facial nerve. The muscle contractions are more rapid and transient
than those of blepharospasm, and the condition is always confined to one
side
How Does Blepharospasm Begin?
Blepharospasm usually begins gradually with excessive blinking and/or eye
irritation. In the early stages it may only occur with specific
precipitating stressors, such as bright lights, fatigue, and emotional
tension. As the condition progresses, it occurs frequently during the day.
The spasms disappear in sleep, and some people find that after a good
night's sleep, the spasms don't appear for several hours after waking.
Concentrating on a specific task may reduce the frequency of the spasms. As
the condition progresses, the spasms may intensify so that when they occur,
the patient is functionally blind; and the eyelids may remain forcefully
closed for several hours at a time.
What Causes Blepharospasm?
Blepharospasm 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 movements. We still do not know what goes wrong in
the basal ganglia. It may be there is a disturbance of various "messenger"
chemicals involved in transmitting information from one nerve cell to
another. In most people blepharospasm develops spontaneously with no known
precipitating factor. However, it has been observed that the signs and
symptoms of dry eye frequently precede and/or occur concomitantly with
blepharospasm. It has been suggested that dry eye may trigger the onset of
blepharospasm in susceptible persons. Infrequently, it may be a familial
disease with more than one family member affected. Blepharospasm can occur
with dystonia affecting the mouth and/or jaw (oromandibular dystonia, Meige
syndrome). 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.
When it is due to antiparkinsonian drugs, reducing the dose alleviates the
problem.
What are the Current Forms of Therapy?
Medical (Drug) Treatment
Drug therapy for blepharospasm is difficult. Medications have different
mechanisms of action and generally produce unpredictable and short-lasting
benefits. One drug may work for some patients and not for others. When the
effects of one drug wear off, sometimes the replacement with another drug
helps. There is, therefore, no fixed or best regimen. Establishing a
satisfactory treatment scheme requires patience on the part of both the
physician and the patient. The following drugs may be tried: Artane (trihexyphenidyl),
Cogentin (benztropine), Valium (diazepam), Klonapin (clonazepam), Lioresal (baclofen),
Tegretol (carbamazepine), Sinemet or Modopar (levodopa), Parlodel (bromocriptime),
and Symmetrel (amantadine). This list is by no means complete, and there are
many more new drugs being developed. The use of these medications requires
close supervision from a neurologist, and it is important that the patient
does not change the dosage or stop the medications without consulting
his/her neurologist.
Surgery
Before surgery is recommended, patients are advised to try safe, potentially
efficacious, nonsurgical therapy such as botulinum toxin injections.
Functionally impaired patients with blepharospasm who have not tolerated or
responded well to medication or botulinum toxin are candidates for surgical
therapy. At present, protractor myectomy (removal of some or all of the
muscles responsible for eyelid closure ) has proven to be the most effective
surgical treatment for blepharospasm. Current experience has found that
myectomy has improved visual disability in 75-80% of cases of blepharospasm.
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