Benign essential blepharospasm (BEB) is a progressive neurological disorder characterized by involuntary muscle contractions and spasms and twitching of the eyelid muscles. It is a form of dystonia, a movement disorder where muscle contractions cause sustained eyelid closure, twitching or repetitive movements. BEB starts gradually with increased frequency of eye blinking often associated with irritation of the eye.

In most BEB cases, the treatment of choice is botulinum toxin injections, with Botox as the most commonly used formulation. These injections relax the muscles and stop the spasms. Most individuals with BEB have substantial relief of symptoms from botulinum toxin injections. Although some patients may experience side effects like drooping eyelids, blurred or double vision, and eye dryness, these side effects are usually only transient. Other treatment options include drug therapy or surgery.

Symptoms may include involuntary winking or squinting of one or both eyes, progressive difficulty in keeping the eyes open, and sensitivity to light. Generally, the spasms occur during the day, disappear in one's sleep, and reappear after waking. As the condition progresses, the spasms may become more intense, forcing the eyelids to remain closed for long periods of time, causing substantial visual disturbance or functional blindness. Important to note is the fact that the blindness is caused solely by the uncontrollable closing of the eyelids and not by any dysfunction of the eyes. BEB occurs in both sexes, although it is especially common in middle-aged and elderly women.

Benign essential blepharospasm is thought to be due to the 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 the body makes. It is still unknown what goes wrong in the basal ganglia. A disturbance of various "messenger" chemicals may be involved in transmitting information from one nerve cell to another. In most people, blepharospasm develops all of a sudden with no known precipitating factor. However, it has been observed that the signs and symptoms of dry eye frequently happen before or occur together with blepharospasm. One suggestion is that dry eye may trigger the onset of blepharospasm in susceptible persons. Less frequently may be a familial disease with more than one person in the family affected. Blepharospasm can occur together with dystonia affecting the mouth or jaw. In such cases, spasms of the eyelids occur together with clenching or mouth opening, grimacing, and tongue protrusion. Blepharospasm can be also induced by drugs, such as those used to treat Parkinson's disease. When it is due to antiparkinsonian drugs, reducing the dose helps alleviate the problem.

benignessentialblepharospasm