WHAT IS BLEPHAROSPASM?
How does Blepharospasm begin?
Blepharospasm usually begins gradually with excessive blinking and/or eye irritation, sometimes only in one eye. 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 is 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.
Types of Blepharospasm
Primary blepharospasm — usually occurs without the symptoms of any other neurological or metabolic disease; considered to be caused by changes in the brain that have not yet been identified; most common type of blepharospasm.
Secondary blepharospasm — attributed to an outside factor such as physical trauma, exposure to certain medications, or additional neurological or metabolic diseases; sometimes associated with brain lesions or drugs.
If you are newly diagnosed, or even if you have yet to be officially diagnosed, we have helpful information for you. If you are currently undiagnosed, please see the list of signs and symptoms of blepharospasm and its related disorders below. It can be challenging to get a diagnosis because many doctors, including specialists, are unfamiliar with blepharospasm. The BEBRF office will gladly help you find a doctor – typically a neurologist or ophthalmologist – in your area who can provide an official diagnosis and ongoing treatment.
Whether you have yet to be diagnosed, are newly diagnosed, or just new to BEBRF, you will find a wealth of information if you click on the New Patient Packet link below.
SIGNS & SYMPTOMS
Early Signs & Symptoms
- Dry Eyes
- Light Sensitivity
- Occasionally increased blinking, winking, or squinting
- Sometimes appear on one side only
- First symptoms are often noticed while drivig
Progressing Signs & Symptoms
- Increased blinking, squinting, or forced eyelid closure
- Eyelids clamp shut and eyebrows pull down
- Symptoms may become so severe that the patient becomes functionally blind
- May develop lower facial problems such as grimacing of the mouth
- May develop breathing problems
It is thought that blepharospasm may have a genetic basis, however, that basis is complex.
Blepharospasm does not appear to be caused by a single genetic mutation. Changes in at least 14 different genes have been associated with blepharospasm and other dystonias.
While 11-30% of people with blepharospasm have a relative who also has a type of focal dystonia, the majority of patients do not. This could partly be explained by incomplete penetrance, meaning not all individuals who carry a particular genetic variant will develop the disease. Someone with a genetic predisposition may have to undergo a triggering event or condition such as dry eyes or trauma for a disease to occur.
It is also possible that two or more genetic variants must exist in a single patient for Blepharospasm to emerge. This is called “Oligogenic inheritance”.
An easy-to-understand discussion of penetrance can be found here:
Further detail on Genetics and Blepharospasm and Dystonia can be found here:
- Genetic Sequence Variants in Primary Dystonia – LeDoux – 2011
- Genetics – Ozelius – 2009
- Genetics of Blepharospasm – Hallett – 1996
- Three New Primary Dystonia Genes Identified by Next-Generation Sequencing – Ozelius – 2013
- Using Exome Sequencing to find Primary Blepharospasm Genes – Fuchs – Ozelius – 2013