Benign essential blepharospasm (BEB) is a cerebral focal and functional dystonia characterized by involuntary excessive blinking that can lead, in severe cases, to functional blindness due to the impossibility of re-opening the eyes at will.
The prevalence is estimated at approximately 1/33,000. BEB is more frequent in women (2/3 of cases).
BEB usually manifests in late adulthood (50-70 years of age) and begins gradually with frequent blinking, eye irritation, and/or photophobia. As the condition progresses, blinking occurs more frequently and involuntary spasms may intensify to a point that when they occur, eyelids remain forcefully closed for several hours at a time and patients become functionally blind. The first tasks affected by BEB are watching television and reading, then driving and walking outside. Finally, patients may injure themselves indoors and falls can occur. In the early stages, BEB may only occur with specific precipitating stressors, such as bright lights, fatigue, and emotional tension. The spasms disappear during sleep. Concentrating on a specific task (song, whistle) may reduce the frequency of the spasms. Dry eye syndrome is frequently associated with BEB. In rare cases, blepharospasm can be associated with oromandibular dystonia (Meige syndrome; see this term).
The etiology remains unknown, even if dysfunction of the basal ganglia seems to play a role in the etiopathogenesis of the disease.
The diagnosis is clinical, based on questioning and examination. No cerebral MRI or CT scan is required.
Differential diagnosis includes hemifacial spasm, oromandibular dystonia (see these terms), other facial dystonias (spasmodic entropion, unilateral palpebral spasm), facial or palpebral tic, apraxia of eyelid opening, blepharitis, ocular allergies, and secondary blepharospasm due to eye surface pathology.
The majority of BEB cases are sporadic.
The treatment is based on neurobotulinum toxin A injections. In some cases, surgery (orbicular myectomy or frontalis suspension) can be proposed.
BEB is not life-threatening. It is usually stable and can exceptionally improve but it can worsen, in duration, frequency, and/or extend to other muscles. Spasms can intensify to such an extent that when they occur, the patient is functionally blind.
Last update: December 2011