The normal adult blinks at a rate of 10 to 20 times per minute. This tends to be reduced when reading or using the computer. An increase in lid closure frequency and tone is known as blepharospasm. This is a focal dystonia appearing in adults with recurrent spasms of eye closure; the orbicularis oculi muscle contracts forcibly and involuntarily. This lasts for periods varying from seconds to minutes and often repeatedly. The spectrum of disease ranges from an increased blink rate with occasional spasms to a severe, disabling and painful condition. Occasionally, it can be so intense as to make the patient effectively blind.
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Most cases are idiopathic and termed benign essential blepharospasm or primary blepharospasm. The circuit involved in blinking involves a sensory limb, a central control area in the midbrain and a motor limb. It is thought that there is a defect in this neuronal circuit activity. The precise mechanism is not known but it is likely that there is more than one defective locus resulting in neurotransmission overload and blepharospasm. There are cases of secondary blepharospasm due to identifiable organic disease. Common ocular causes include:
- Eye trauma (mechanical, chemical or thermal) - particularly to the cornea - will cause acute blepharospasm
- Dry eye
- Other chronic lid disease or ocular surface disease
- Multiple sclerosis (may cause blepharoclonus - prolonged, severe and painful eyelid closure)
- Focal brain injury, particularly of the basal ganglia
- Atypical Parkinson's disease/multiple system atrophy/progressive supranuclear palsy
- Adverse drug reactions, eg olanzapine, tardive dyskinesia
- Tourette's syndrome
- Cerebral palsy
- Familial cases
Prevalence is estimated at 16 to 133 per million. Essential blepharospasm affects women about twice as commonly as men. It is more common in older age and typically develops in the sixth decade.
- Spasms of eye closure usually occur in bright light or when reading or watching television. Driving, fatigue stress can also bring the spasms on.
- Concentration on a task may improve or abate the spasms or reduce their frequency. Talking, whistling, touching the face, walking and relaxation have also been found to improve the problem.
- There may be associated eye irritation, midfacial or lower facial spasm, brow spasm and eyelid tic.
- Nocturnal symptoms are unusual.
- It may be linked with an oromandibular dystonia characterised by recurrent spasms of face, oropharynx, larynx. This causes spasms of lip and jaw movement, chin jutting and problems with speaking and swallowing. Patients may develop oromandibular dystonia after blepharospasm and vice versa. Where blepharospasm is the main feature this is called Meige's syndrome.
- Brueghel's syndrome is characterised by blepharospasm associated with severe mandibular and cervical muscle involvement.
- Cognitive dysfunction has been reported in these patients but has not been widely studied and therefore little is known of this at present.
- Untreated, the condition can cause severe psychological distress and is associated with significant psychiatric comorbidity.
Reflex blepharospasm to a secondary cause must be ruled out but, otherwise, isolated blepharospasm does not usually require investigating. Any associated neurological problem should prompt a neurology review.
The Blepharospasm Disability Index is a scale used to assess the functional impairment in these patients. It may be used in a specialist setting to assess treatment outcomes and is also a useful research tool.
- Blepharospasm can be a reflex reaction to an underlying disease (most commonly, ocular surface disease) and this needs to be ruled out/managed before drugs are considered for the blepharospasm.
- Wearing dark glasses can reduce bright light triggers and prevent embarrassment due to the stares of onlookers.
- Voluntary manoeuvres, such as pulling the eyelid, pinching the neck, talking, yawning, humming and singing, help some sufferers.
- Patients with severe blepharospasm must not drive. Those with mild or well-controlled blepharospasm may drive subject to a consultant's approval.
- Blepharospasm does not respond well to antispasmodics or benzodiazepines.
- A number of drugs have been tried with varying success with different types of blepharospasm but, overall, their efficacy is limited. Tetrabenazine has been shown to be of moderate benefit in some patients.
- Preferred treatment is injection of botulinum toxin type A into the orbicularis oculi muscle. A Cochrane systematic review found the treatment to be highly effective, helping up to 90% of patients compared with placebo.
A starting dose is usually in the region of 10-20 units per injection site and subsequent treatment is determined by the patient's response (there may be a need for a slight increase or decrease in units given). Most patients need re-treatment every three months or so and progressively larger doses may be needed over a long period of time.
Side-effects include lagophthalmos, ectropion or entropion. Epiphora, dry eye and occasionally associated keratitis have also been noted. Accidental migration of the toxin into the orbit can result in a ptosis ± diplopia. All these effects (as well as the beneficial ones) wear off over three to four months.
Where vision is severely impaired by prolonged, severe eye closure, unresponsive to pharmacological techniques, protractor myomectomy may be used (removal of some muscles of eye closure). Its use will only be considered as a last resort.
Most cases of primary blepharospasm cannot be cured although symptomatic relief is good with botulinum toxin injections. The long-term safety and efficacy of this drug appears to be excellent.
Further reading & references
- Baker R in Oxford Textbook of Medicine, 4th Edition. Eds. Warrel DA et al. OUP 2003.
- BEBRF; Benign Essential Blepharospasm Research Foundation. Resources including patient information; note - based in the United States.
- Graham RH; Blepharospasm, Benign. eMedicine (June 2009).
- Denniston AKO, Murray PI. Oxford Handbook of Ophthalmology (OUP), 2009.
- Jacome DE; Blepharoclonus in multiple sclerosis. Acta Neurol Scand. 2001 Dec;104(6):380
- Shimizu E, Otsuka A, Hashimoto K, et al; Blepharospasm associated with olanzapine: a case report. Eur Psychiatry. 2004 Sep;19(6):389.
- Defazio G, Brancati F, Valente EM, et al; Familial blepharospasm is inherited as an autosomal dominant trait and relates to a novel unassigned gene. Mov Disord. 2003 Feb;18(2):207
- Defazio G, Livrea P; Epidemiology of primary blepharospasm. Mov Disord. 2002 Jan;17(1):7
- Kanski J. Clinical Ophthalmology; A Systematic Approach (5th Ed) Butterworth Heinemann (2003)
- Stamey W, Jankovic J; The other Babinski sign in hemifacial spasm. Neurology. 2007 Jul 24;69(4):402-4.
- Aleman GG, de Erausquin GA, Micheli F; Cognitive disturbances in primary blepharospasm. Mov Disord. 2009 Oct 30;24(14):2112-20.
- Wenzel T, Schnider P, Griengl H, et al; Psychiatric disorders in patients with blepharospasm J Psychosom Res. 2000 Jun;48(6):589
- Dystonia Medical Research Foundation. Blepharospasm
- Paleacu D, Giladi N, Moore O, et al; Tetrabenazine treatment in movement disorders. Clin Neuropharmacol. 2004 Sep
- Cillino S, Raimondi G, Guepratte N, et al; Long-term efficacy of botulinum toxin A for treatment of blepharospasm, Eye. 2009 Jul 24.
- Bentivoglio AR, Fasano A, Ialongo T, et al; Fifteen-year experience in treating blepharospasm with Botox or Dysport: same Neurotox Res. 2009 Apr;15(3):224-31. Epub 2009 Feb 24.
|Original Author: Dr Hayley Willacy||Current Version: Dr Olivia Scott|
|Last Checked: 11/12/2009||Document ID: 1873 Version: 21||© EMIS|
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