Blepharospasm | |
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Other names | Eye dystonia, Eye twitching, Eye spasm |
Pronunciation | |
Specialty | Neurology, ophthalmology |
Blepharospasm is a neurological disorder characterized by intermittent, involuntary spasms and contractions of the orbicularis oculi (eyelid) muscles around both eyes. [1] [2] [3] [4] These result in abnormal twitching or blinking, and in the extreme, sustained eyelid closure resulting in functional blindness.
The word blepharospasm is derived from the Greek: βλέφαρον / blepharon, eyelid, and σπασμός / spasmos, spasm, an uncontrolled muscle contraction. The condition should be distinguished from the more common, and milder, involuntary quivering of an eyelid, known as myokymia or fasciculation.
Blepharospasm is one form of a group of movement disorders called dystonia. [4] It may be a primary or secondary disorder. The primary disorder is benign essential blepharospasm, in which term the qualifier essential indicates that the cause is unknown. Blepharospasm may occur as secondary to conditions including dry eyes and other specific ocular disease or conditions, Meige's Syndrome and other forms of dystonia, and Parkinson's Disease and other movement disorders. [3]
Blepharospasm occurs in middle age and is more frequent among women than men. The most common treatments are medication and periodic injections of botulinum toxin into the eyelid muscles.
Blepharospasm is a fairly rare disease. Estimates of incidence and prevalence vary, tending to be higher in population studies than service studies, [5] likely because of delays in diagnosis. [4] In the United States, approximately 2,000 new cases of blepharospasm are diagnosed each year. [6] Estimates of incidence per million persons-years range from 14.5 in Northern California [7] to 100 in Taiwan. [8] Estimates of prevalence per million range from 12 in Olmsted County, Minnesota [9] to 133 in Puglia, Southern Italy. [10]
The onset of blepharospasm tends to be during the ages 40–60. [8] [10] [11] The condition is roughly more than twice as frequent among females than males, [7] [8] [11] which may be related to menopause and hormone treatments. [12] [13] In Taiwan, the condition is more frequent among white- than blue-collar workers. [8]
Blepharospasm usually begins with occasional twitches of both eyelids, which progress over time to forceful and frequent spasms and contractions of the eyelids. In severe episodes, the patient cannot open their eyelids (apraxia), which severely limits their daily activities. Prolonged closure of the eyelids may result in functional blindness. [4]
Patients suffering from blepharospasm also report sensory symptoms including sensitivity to light, [14] [15] dry eyes, [16] and burning sensation and grittiness in the eyes. [4] Although such symptoms tend to precede the onset of the blepharospasm, they may both be due to a common third factor. [17]
Typically, the symptoms—spasms and contractions of the eyelids—tend to worsen when the patient relaxes but abate during sleep. [18] The symptoms may be temporarily alleviated by sensory tricks (geste antagoniste) including stretching or rubbing the eyebrows, eyelids, or forehead, [19] and singing, talking, or humming. [20] Blepharospasm is aggravated by fatigue, stress, and environmental factors such as wind or air pollution. [21]
Although blepharospasm is defined as a bilaterally symmetric disorder that affects both eyes, some research has reported unilateral onset. [11] [22]
Historically, it was believed that blepharospasm was due to the abnormal functioning of the brain's basal ganglia. [23] The basal ganglia are structures in the brain that are involved in the regulation of motor and reward functions.
However, blepharospasm is now known to involve several regions of the brain and to be a multifactorial condition in which "one or several as yet unknown genes together with epigenetic and environmental factors combine to reach the threshold that induces the disease". [3]
Blepharospasm is often associated with dry eyes, but the causal mechanism is still not clear. [16] [8] Research in New York and Italy suggests that increased blinking (which may be triggered by dry eyes) leads to blepharospasm. [24] [25] A case control study in China found that blepharospasm aggravated dry eyes. [26]
Blepharospasm may be associated with dystonia in other parts of the body, particularly Meige's Syndrome. [27] [28] [4] Blepharospasm may be associated with Parkinson's Disease, but the causal mechanism is still not clear. [29] [30] In rare cases, blepharospasm is associated with multiple sclerosis. [31] [32]
Some drugs can induce blepharospasm, including those used to treat depression [33] [34] and Parkinson's disease. [35] Hormone replacement therapy for women going through menopause has been found to be associated with dry eyes, [13] which in turn is associated with blepharospasm.
Blepharospasm can be caused by concussions in some rare cases, when a blow to the back of the head damages the basal ganglia. [36]
Blepharospasm is associated with exposure to the sun. [37]
No laboratory tests exist with which to definitively diagnose blepharospasm. Historically, the condition was frequently misdiagnosed, [18] often as a psychiatric condition. [6]
Diagnosis of blepharospasm has been enhanced by the proposal of objective diagnostic criteria that start from "stereotyped, bilateral and synchronous orbicularis oculi spasms" and proceed to the identification of a "sensory trick" or "increased blinking". [38] The criteria have been validated across multiple ethnicities in multiple centers. [39]
Standard first line treatments of blepharospasm are conservative therapies, oral medication, and periodic injections of botulinum toxin.
Particularly when associated with dry eyes, blepharospasm may be relieved with warm compresses, eye drops, and eye wipes. [40] [41] A Japanese study showed that warm compresses containing menthol were more effective in increasing tear film. [42]
Drugs used to treat blepharospasm are anticholinergics, benzodiazepines, baclofen, and tetrabenazine. [43] The proportion of patients who benefited from anticholinergics ranged from 1 in 9 in Oregon [44] to 1 in 5 in England. [11] Besides failing to resolve the blepharospasm, some drugs present the risk of side effects. In Japan, use of etizolam and benzodiazepine was associated with the development of blepharospasm. [33] [34] A case report from Sri Lanka suggests treatment with Mosapride. [45]
The main first-line therapy is periodic injections of botulinum toxin type A to induce localized, partial paralysis of the eyelid muscles. [46] [47] Injections are generally administered at intervals of around 10 weeks, with variations based on patient response and usually give fairly quick relief from the muscle spasms. An English study reported that 118 (78%) of 151 patients experienced significant relief of symptoms for a mean duration of 9.2 weeks. [11] However, in a minority of patients, the injections do not provide any symptomatic relief. Injections of botulinum toxin may diminish in effectiveness with prolonged use and require increased dosage. [48] Injections of botulinum toxin increase the risk of visual complaints and ptosis (eyelid droop). [46]
Patients who do not respond well to medication or botulinum toxin injections are candidates for surgical therapy. The most effective surgical treatment has been protractor myectomy, the removal of muscles responsible for eyelid closure. [49] Myectomy is more effective than distal neurectomy. [50]
A case report from California suggests the use of intense pulsed light therapy to relieve blepharospasm. [51] Patients suffering from blepharospasm may get relief by wearing spectacles fitted to lift the upper eyelid. [43] Among complementary therapies, two simulate sensory tricks: Attaching a device to spectacle frames to press on the patient's temple, [52] and applying thin cosmetic tapes to the forehead and eyebrows. [53] Another complementary therapy is retraining the brain to "rewire" itself and eliminate dystonic movements. Associated with Joaquin Farias, sensorimotor retraining activities and proprioceptive stimulation aim to induce neuroplasticity, making it possible for patients to recover substantial function that was lost due to blepharospasm. [54] Complementary therapies lack evidence of the highest quality (Level 1).
The U.S. National Library of Medicine maintains a register of clinical trials of therapies to treat blepharospasm.
Blepharospasm Research Foundation
Neuroplasticity training
Botulinum toxin, or botulinum neurotoxin, is a highly potent neurotoxic protein produced by the bacterium Clostridium botulinum and related species. It prevents the release of the neurotransmitter acetylcholine from axon endings at the neuromuscular junction, thus causing flaccid paralysis. The toxin causes the disease botulism. The toxin is also used commercially for medical and cosmetic purposes. Botulinum toxin is an acetylcholine release inhibitor and a neuromuscular blocking agent.
Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia, rigidity, and postural instability. Both hypokinetic as well as hyperkinetic features are displayed by Parkinsonism. These are the four motor symptoms found in Parkinson's disease (PD) – after which it is named – dementia with Lewy bodies (DLB), Parkinson's disease dementia (PDD), and many other conditions. This set of symptoms occurs in a wide range of conditions and may have many causes, including neurodegenerative conditions, drugs, toxins, metabolic diseases, and neurological conditions other than PD.
Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom, photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical sensitivity of the eyes, though the term is sometimes additionally applied to abnormal or irrational fear of light, such as heliophobia. The term photophobia comes from Greek φῶς (phōs) 'light' and φόβος (phóbos) 'fear'.
Writer's cramp or focal hand dystonia (FHD) is an idiopathic movement disorder of adult onset, characterized by abnormal posturing and movement of the hand and/or forearm during tasks requiring skilled hand use, such as writing. Overcontraction of affected muscles, cocontraction of agonist and antagonist pairs, and activation of muscles inappropriate to a task all impair use of the affected hand.
Dystonia is a neurological hyperkinetic movement disorder in which sustained or repetitive muscle contractions occur involuntarily, resulting in twisting and repetitive movements or abnormal fixed postures. The movements may resemble a tremor. Dystonia is often intensified or exacerbated by physical activity, and symptoms may progress into adjacent muscles.
Hyperkinesia refers to an increase in muscular activity that can result in excessive abnormal movements, excessive normal movements, or a combination of both. Hyperkinesia is a state of excessive restlessness which is featured in a large variety of disorders that affect the ability to control motor movement, such as Huntington's disease. It is the opposite of hypokinesia, which refers to decreased bodily movement, as commonly manifested in Parkinson's disease.
Focal dystonia, also called focal task-specific dystonia, is a neurological condition that affects a muscle or group of muscles in a specific part of the body during specific activities, causing involuntary muscular contractions (spasms) and abnormal postures. There are many different types of focal dystonia, each affecting a different region of the body. For example, in focal hand dystonia, or writer's cramp, the fingers either curl into the palm or extend outward without control. In musicians, the condition is called musician's focal dystonia, or simply, musician's dystonia. In sports, it may be involved in what is commonly referred to as the yips. The condition appears to be associated with over-training, and individualized treatment strategies may involve medications, retraining techniques, and procedures.
Neuro-ophthalmology is an academically-oriented subspecialty that merges the fields of neurology and ophthalmology, often dealing with complex systemic diseases that have manifestations in the visual system. Neuro-ophthalmologists initially complete a residency in either neurology or ophthalmology, then do a fellowship in the complementary field. Since diagnostic studies can be normal in patients with significant neuro-ophthalmic disease, a detailed medical history and physical exam is essential, and neuro-ophthalmologists often spend a significant amount of time with their patients.
Hemifacial spasm (HFS) is a rare neuromuscular disease characterized by irregular, involuntary muscle contractions (spasms) on one side (hemi-) of the face (-facial). The facial muscles are controlled by the facial nerve, which originates at the brainstem and exits the skull below the ear where it separates into five main branches.
Torsion dystonia, also known as dystonia musculorum deformans, is a disease characterized by painful muscle contractions resulting in uncontrollable distortions. This specific type of dystonia is frequently found in children, with symptoms starting around the ages of 11 or 12. It commonly begins with contractions in one general area such as an arm or a leg that continue to progress throughout the rest of the body. It takes roughly 5 years for the symptoms to completely progress to a debilitating state.
Spasmodic torticollis is an extremely painful chronic neurological movement disorder causing the neck to involuntarily turn to the left, right, upwards, and/or downwards. The condition is also referred to as "cervical dystonia". Both agonist and antagonist muscles contract simultaneously during dystonic movement. Causes of the disorder are predominantly idiopathic. A small number of patients develop the disorder as a result of another disorder or disease. Most patients first experience symptoms midlife. The most common treatment for spasmodic torticollis is the use of botulinum toxin type A.
Meige's syndrome is a type of dystonia. It is also known as Brueghel's syndrome and oral facial dystonia. It is actually a combination of two forms of dystonia, blepharospasm and oromandibular dystonia (OMD).
The signs and symptoms of multiple sclerosis (MS) encompass a wide range of neurological and physical manifestations, including vision problems, muscle weakness, coordination difficulties, and cognitive impairment, varying significantly in severity and progression among individuals.
Spasmodic dysphonia, also known as laryngeal dystonia, is a disorder in which the muscles that generate a person's voice go into periods of spasm. This results in breaks or interruptions in the voice, often every few sentences, which can make a person difficult to understand. The person's voice may also sound strained or they may be nearly unable to speak. Onset is often gradual and the condition is lifelong.
Myoclonic dystonia or Myoclonus dystonia syndrome is a rare movement disorder that induces spontaneous muscle contraction causing abnormal posture. The prevalence of myoclonus dystonia has not been reported, however, this disorder falls under the umbrella of movement disorders which affect thousands worldwide. Myoclonus dystonia results from mutations in the SGCE gene coding for an integral membrane protein found in both neurons and muscle fibers. Those suffering from this disease exhibit symptoms of rapid, jerky movements of the upper limbs (myoclonus), as well as distortion of the body's orientation due to simultaneous activation of agonist and antagonist muscles (dystonia).
Oromandibular dystonia(OMD) is an uncommon focal neurological condition affecting the jaws, face, and mouth. Oromandibular dystonia is characterized by involuntary spasms of the tongue, jaw, and mouth muscles that result in bruxism, or grinding of the teeth, and jaw closure. These conditions frequently lead to secondary dental wear as well as temporomandibular joint syndrome. In addition, problems with chewing, speaking, and swallowing may result from jaw opening, involuntary tongue movements, or jaw deviation.
Botulinum toxin therapy of strabismus is a medical technique used sometimes in the management of strabismus, in which botulinum toxin is injected into selected extraocular muscles in order to reduce the misalignment of the eyes. The injection of the toxin to treat strabismus, reported upon in 1981, is considered to be the first ever use of botulinum toxin for therapeutic purposes. Today, the injection of botulinum toxin into the muscles that surround the eyes is one of the available options in the management of strabismus. Other options for strabismus management are vision therapy and occlusion therapy, corrective glasses and prism glasses, and strabismus surgery.
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Alan Brown Scott was an American ophthalmologist specializing in eye muscles and their disorders, such as strabismus. He is best known for his work in developing and manufacturing the drug that became known as Botox, research described as "groundbreaking" by the ASCRS.
Mark Hallett is an American neurologist who researched the physiology of human movement and movement disorders including functional motor disorders at the NIH, and currently serves as Distinguished NIH Investigator Emeritus. Hallett worked at NIH for 40 years in the federal government, with several decades at the Human Motor Control Section and was previously chief of the Clinical Neurophysiology Laboratory at Brigham Women's Hospital.