blepharospasm

Blepharospasm is a focal dystonia characterized by involuntary, often forceful closure or squeezing of the eyelids due to dystonic contractions of the orbicularis oculi and related facial muscles. It commonly begins with increased blinking and photophobia and can progress to spells of frequent eyelid closure that interfere with vision.

Etiology and presentation: Most cases are idiopathic or related to a genetic predisposition, with abnormal function in basal ganglia circuits and sensorimotor integration. Triggers include bright light, fatigue, stress, and ocular surface irritation. When jaw or facial muscles are involved, the condition may be part of Meige syndrome.

Clinical features: Patients experience episodes of eyelid closure that may last seconds to minutes, often accompanied by excessive blinking, eye irritation, and photophobia. Vision may be temporarily obscured during spasms, but the underlying visual acuity is typically unaffected. Dry eye symptoms can exacerbate the condition.

Diagnosis: Diagnosis is clinical, based on history and examination. It is important to differentiate blepharospasm from ocular surface disease, myasthenia gravis, lagophthalmos, and other movement disorders. Electromyography can support the diagnosis in uncertain cases or guide injection planning.

Treatment: First-line therapy is botulinum toxin injections into the pretarsal and lateral orbicularis oculi muscles, with onset within days and effects lasting about 2–4 months requiring repeated treatment. Adjuncts include lubrication, protective eyewear, and management of contributing eye disease. Oral medications have limited efficacy and are generally avoided due to side effects. Refractory cases may require surgical options such as eyelid procedures, and in severe or generalized dystonia, deep brain stimulation may be considered.