What is Blepharospasm?
Blepharo means "eyelid". Spasm means "uncontrolled muscle contraction". The term blepharospasm ['blef-a-ro-spaz-m] can be applied to any abroutine blinking or eyelid tic or twitch resulting from any cause, ranging from dry eyes to Tourette's disorder 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 represent s abroutine involuntary uninterrupted muscle contractions and spasms. Patients with blepharospasm have routine eyes. The visual derangement is due solely to the forced closure of the eyelids.Blepharospasm should not be confused with:
- Ptosis - drooping of the eyelids generate by weakness or paralysis of a levator muscle of the upper eyelid.
- Blepharitis - an provocative condition of the lids due to epidemic or allergies.
- Hemifacial spasm - a non-dystonic condition involving various tendon on one side of the face, repeatedly including the eyelid, and generate by excitability 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.
The first part of Dr. Miller's video, "Diagnosis & Medication with Botox of Patients with Benign Essential Blepharospasm & Related Disorders", shows different ways in which blepharospasm may manifest itself.
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 bellyache , such as bright lights, weariness , and emotional tension. As the condition progresses, it transpire 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 abroutine functioning of the basal ganglia which are situated at the base of the brain. The basal ganglia play a role in all conduce movements. We still do not know what goes wrong in the basal ganglia. It may be there is a derangement 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 realized that the signs and symptoms of dry eye frequently precede and/or occur concomitantly with blepharospasm. It has been propose ed 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 disorder ). 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.