Blepharospasm is characterized by excessive and involuntary closing or blinking of the eyes. This disorder, the cause of which is often unknown, is usually treated with an injection of botulinum toxin.

Definition of blepharospasm

In medical parlance, blepharospasm is focal dystonia (or localized dystonia). It is a disorder characterized by sustained and involuntary muscle contractions. In the case of blepharospasm, dystonia involves the muscles of the eyelids. These contract involuntarily, unpredictably and repeatedly. These contractions cause involuntary blinking and partial or complete eye closures.

Blepharospasm can be unilateral or bilateral, involving one or both eyelids. It can be isolated by relating exclusively to the eyelids, or can be accompanied by other dystonias. That is, muscle contractions at other levels can be seen. When other muscles of the face are involved, it is called Meige syndrome. When the contractions occur in different areas of the body, it is called generalized dystonias.

Causes of blepharospasm

The origin of blepharospasm is generally unknown.

In some cases, blepharospasm has been found to be secondary to eye irritation which may be caused by the presence of a foreign body or keratoconjunctivitis sicca (dry eye). Some systemic neurological diseases, such as Parkinson’s disease, can also cause the involuntary muscle contractions characteristic of blepharospasm.

Diagnosis of blepharospasm

The diagnosis is based on a clinical examination. Additional tests may be ordered by the doctor to rule out other possible explanations and try to identify the cause of blepharospasm.

Blepharospasm has been found to affect women more often than men. It would seem that there may also be a family component.

Risk factors

Blepharospasm can be accentuated in certain situations:

• tiredness,
• intense light,
• anxiety.

Blinks and eye closures

Blepharospasm is characterized by involuntary contractions of the muscles of the eyelids. These translate into:

• excessive and involuntary blinking or blinking;
• partial or total involuntary closures of the eyes.

Only one eye or both eyes may be affected.

Vision disturbances

In the most severe cases and in the absence of adequate treatment, blepharospasm can cause visual discomfort. It can become more complicated and cause an inability to open the eye or both eyes.

Daily discomfort

Blepharospasm can interfere with daily activities. When it causes significant visual disturbances, it can lead to social complications with the inability to move and work.

Management of the cause

If a cause has been identified, it will be treated to allow remission of the blepharospasm. The use of artificial tears may for example be recommended in the event of keratoconjunctivitis sicca.

Botulinum toxin injection

This is the first-line treatment for blepharospasm with no known cause and / or persistent. It consists of injecting very low doses of botulinum toxin into the muscles of the eyelids. Substance extracted and purified from the agent responsible for botulism, botulinum toxin helps block the transmission of nerve impulses to the muscles. In this way, the muscle responsible for the contractions is paralyzed.

This treatment is not definitive. Botulinum toxin injections are needed every 3 to 6 months.

Surgical intervention

Surgery is considered if botulinum toxin injections prove ineffective. The operation usually involves removing part of the orbicularis muscle from the eyelids.

To date, no solution has been identified to prevent blepharospasm. On the other hand, certain preventive measures are recommended for people with blepharospasm. In particular, they are advised to wear tinted glasses to reduce sensitivity to light, and thus limit involuntary contractions of the eyelid muscles.