Benign essential blepharospasm (BEB) is an idiopathic disorder of progressive involuntary spasms of orbicularis oculi and upper facial muscles leading to closure of eyelids. BEB is a bilateral condition and a form of focal dystonia (repetitive involuntary sustained muscle contraction) characterised by episodic contraction of protractor (drawing a part forward) muscles (orbicularis oculi, procerus and corrugator superciliaris) and is not associated with another disease. Severe blepharospasm may temporarily make patient functionally blind. Blepharospasm may be precipitated by factors such as reading, bright light, driving or stress and alleviated by talking, relaxation or walking.
BEB should be differentiated from blepharospasm that can exist as part of specific condition (secondary blepharospasm) such as:-
Meige’s syndrome: Meige’s syndrome is characterised by blepharospasm with involvement of the lower facial and neck muscles.
Breughel’s syndrome: Breughel’s syndrome (oromandibular dystonia) is association of blepharospasm with severe mandibular and cervical muscle involvement.
Extrapyramidal disorders: Systemic disease such as extrapyramidal disorders may be present with blepharospasm.
Reflex blepharospasm: Reflex blepharospasm may be secondary to irritation of ocular surface.
Basak Samar K, Atlas of Clinical Ophthalmology, 2nd ed. Jaypee Brothers Medical Publishers (P) Ltd, 2013, New Delhi, P.28
Kanski,Jack J. Clinical Ophthalmology, A Systematic Approach .Third Edition.UK. Butterworth Heinemann, 1994. P. 494 - 495.
Benign essential blepharospasm may have following symptoms:-
Symptoms preceding diagnosis are:-
Early symptoms of blepharospasm are:-
Exact cause of benign essential blepharospasm is not known.
Some evidence using functional neuroimaging studies, suggests dysfunction within basal ganglia.
Rarely, genetics play a role in some cases. Some patients with blepharospasm have at least one first degree relative with some form of focal dystonia. Rarely, it may be inherited as an autosomal dominant condition.
Blepharospasm may be associated with the use of medications such as:-
Conditions which may occur together with BEB are:-
In normal blinking, eyelid closure results due to the activity and co-inhibition of two groups of muscles, the protractors of the eyelid and the voluntary retractor of the eyelids (e.g. levator palpebrae superioris, frontalis muscle). During normal blink, protractors and retractors function at separate times, so that on activation of protractor muscles, there is inhibition of retractors. In blepharospasm, this inhibition between protractors and retractors is lost.
Diagnosis of BEB is made clinically (based on history and physical examination) and it is a diagnosis of exclusion by ruling out the presence of associated conditions.
Benign Essential Blepharospasm:
At onset of BEB, there is increased frequency of blinking precipitated by stimuli such as wind, sunlight, noise, air pollution, reading, watching television, stress, or movement of eye or head. Patients may develop sensory tricks (‘geste antagoniste’) to relieve symptoms such as tics and movements of other muscles innervated by facial nerve e.g. whistling, coughing, eating, picking teeth, yawning or chewing gum.
Eyelid spasm, a characteristic feature of blepharospasm, sets in a few months to years after early features. Blepharospasm is unilateral to begin with but usually eventually evolves into a bilateral condition. Blepharospasm usually lasts for minutes to hours together. Blepharospasm has a variable course and may be intermittent or continuous. It is slowly progressive in most of the patients.
Excessive blinking may lead to unilateral mild twitches, but may progress to bilateral, frequent and forceful spasms. During severe episodes, patient is unable to open the eyelids which may be associated with severe pain and functional blindness and may interfere with daily routine activities. Severe blepharospasm may cause high level of distress and psychosocial impairment causing anxiety, depression, avoidance of social contact and occupational problems. Blepharospasm reduces while concentrating on a specific task or during sleep.
Blepharospasm may be associated with apraxia (loss of ability to perform activity) of eyelid opening i.e. inhibition of proper functioning of levator palpebrae superioris muscle. Apraxia is especially common in parkinsonian disorders.
Conditions relieving blepharospasm:
Anatomic changes associated with long-standing blepharospasm may be:
Blepharospasm may be differentiated from conditions like:
Management should be under medical supervision.
Currently, there is no cure for BEB and the disease frequently progresses despite treatment.
Surgical management of BEB is usually reserved for patients who are unresponsive or cannot tolerate to botulinum injections.
Surgery can be: