One of the most common types of adult-onset focal dystonia is blepharospasm, characterized by involuntary closure of the eyes. Many patients are initially misdiagnosed as having "dry eyes" but eye drops or lubricants rarely provide any benefit, and rarely is anything found to be wrong with the eyes themselves. About one-third of blepharospasm patients report an increased frequency of blinking, commonly associated with a feeling of irritation in the eyes and light sensitivity (photophobia). The blinking usually progresses to more sustained contractions of the orbicularis oculi (eyelid muscles) leading to forceful closure of eyelids. Blepharospasm is usually exacerbated by bright light (photophobia) and, as a result, many patients wear sunglasses both outside and inside. The spasms may be transiently alleviated by pulling on an upper eyelid or an eyebrow, pinching the neck, talking, humming, yawning, singing, sleeping, relaxing, reading, concentration, looking down, and other alleviating maneuvers. Blepharospasm may vary in severity from only a slightly annoying or embarrassing condition to a disabling disorder that may render the patient functionally blind and interfere with daily activities such as reading, watching television, and driving.
Blepharospasm is seldom an isolated condition; this form of dystonia is often associated with dystonia in other facial, jaw, or neck muscles leading to "cranial-cervical dystonia.鈥 In some patients, the dystonia spreads to involve the vocal cords (spasmodic dysphonia), trunk, and limbs.
Blepharospasm should be differentiated from apraxia of eyelid opening, the inability to voluntarily open the eyes in the absence of eyelid muscle (orbicularis oculi) contraction, despite sustained frontalis contraction. Electrophysiologic studies have suggested it is due to an excessive inhibition of the levator palpebrae superioris muscle, however, the exact pathophysiology remains unclear and several other terms including involuntary levator palpebrae inhibition, blepharocolysis, akinesia and freezing of eyelids, and atypical blepharospasm have been used to describe it. Apraxia of eyelid opening is much more difficult to treat than blepharospasm.
Cause
The cause of blepharospasm is not well understood although dysfunction of the basal ganglia, possibly associated with exaggerated neuroplasticity, has been proposed. Most cases are sporadic (without family history), but many have family history of blepharospasm, tremor or other movement disorder indicating that genetic mechanisms are likely involved. Patients with other neurologic diseases, such as Parkinson鈥檚 disease or lesions in the brainstem and basal ganglia, may develop blepharospasm as well.
Treatment
Botulinum toxin (BTX) injections into the eyelids and eyebrows are now considered the treatment of choice for blepharospasm, providing moderate to marked improvement in over 90 percent of patients. The average latency from the time of the BTX injection to the onset of improvement is two to five days and the average duration is three to four months, after which time the treatment must be repeated in order to sustain the benefit. In addition to the marked functional improvement, there is usually a meaningful amelioration of discomfort and, because of less embarrassment, the patients' self-esteem also frequently improves. Although about 10 to 15 percent of all treatment sessions are followed by some side effects (droopiness of eye lid, blurring of vision or double vision, tearing and local hematoma), the complications only rarely affect patient's functioning and usually resolve spontaneously in less than two weeks. There is no apparent decline in benefit and the frequency of complications actually decreases after repeat BTX treatments. The severity of blepharospasm and its response to treatment is assessed by the Jankovic Rating Scale (JRS).
Apraclonidine or oxymetazoline eye drops that cause contraction of the upper eyelid muscle (Mueller), can be used as a temporary measure while the BTX effect has not started or when it is wearing off, or when patients develop weakness of the upper eyelid (ptosis) as a complication of BTX treatment.
Some patients with blepharospasm have partial relief from medications such as clonazepam, trihexyphenidyl, lorazepam, baclofen and tetrabenazine. However, given their side effects and the significant improvement with BTX, oral medications are not frequently used.
In very severe cases in patients with significant functional impairment who have not responded well to BTX, surgery may be an option. A myectomy, which involves removal of some or all of the muscles responsible for eyelid closure, may be considered (as a last resort). The suspension of a muscle in the forehead with synthetic threads was evaluated in refractory cases with good results in a small study, but the use of this technique in a larger numbers or patients is warranted. The use of deep brain stimulation was also reported in small studies, with success in refractory cases of blepharospasm, particularly when a part of cranio-cervical dystonia.
References
- Anandan C, Jankovic J. Botulinum Toxin in Movement Disorders: An Update. Toxins (Basel). 2021 Jan 8;13(1):42.
- Anandan C, Jankovic J. Use of botulinum toxin in the management of dystonia in Parkinson's disease. Front Neurosci. 2024 Apr 8;18:1371601.
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- Defazio G, Gigante AF, Hallett M, Berardelli A, Perlmutter JS, Berman BD, Jankovic J, B盲umer T, Comella C, Ercoli T, Ferrazzano G, Fox SH, Kim HJ, Moukheiber ES, Richardson SP, Weissbach A, Jinnah HA. Motor and psychiatric features in idiopathic blepharospasm: A data-driven cluster analysis. Parkinsonism Relat Disord. 2022 Nov;104:94-98.
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- Duarte GS, Rodrigues FB, Marques RE, Castel茫o M, Ferreira J, Sampaio C, Moore AP, Costa J. Botulinum toxin type A therapy for blepharospasm. Cochrane Database Syst Rev. 2020;11:CD004900.
- Galor A, Margolis TP, Britten-Jones AC. The Problem With Dry Eye Trials. JAMA Ophthalmol. 2024;142(1):74鈥75.
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- Scorr LM, Cho HJ, Kilic-Berkmen G, McKay JL, Hallett M, Klein C, Baumer T, Berman BD, Feuerstein JS, Perlmutter JS, Berardelli A, Ferrazzano G, Wagle-Shukla A, Malaty IA, Jankovic J, Bellows ST, Barbano RL, Vidailhet M, Roze E, Bonnet C, Mahajan A, LeDoux MS, Fung VSC, Chang FCF, Defazio G, Ercoli T, Factor S, Wojno T, Jinnah HA. Clinical Features and Evolution of Blepharospasm: A Multicenter International Cohort and Systematic Literature Review. Dystonia. 2022;1:10359.
- Vijayakumar D, Wijemanne S, Jankovic J. Treatment of blepharospasm with apraclonidine. J Neurol Sci. 2017 Jan 15;372:57-59.
- Zarifkar P, Shaff NA, Nersesjan V, Mayer AR, Ryman S, Kondziella D. Lesion network mapping of eye-opening apraxia. Brain Commun. 2023 Oct 27;5(6):fcad288.
Benign Essential Blepharospasm Research Foundation (BEBRF)
bebrf@blepharospasm.org
Dystonia Medical Research Foundation (DMRF)
