blepharospasme

Blepharospasm is a focal dystonia characterized by involuntary, repetitive contractions of the muscles around the eyes, leading to episodic or sustained eyelid closure. It most often begins in mid to late adulthood and can occur alone or as part of Meige syndrome, in which blepharospasm is accompanied by oromandibular dystonia. The condition can cause functional impairment due to reduced ability to open the eyes.

Symptoms typically include frequent blinking, forceful eyelid closure, and episodes lasting seconds to minutes. Symptoms may be triggered or worsened by bright light, fatigue, stress, or ocular irritation. Some people report a sensation of eye strain, dry eye, or blurred vision between spasms, which can affect activities such as reading or driving.

Etiology is usually idiopathic, with a genetic predisposition in some cases. Blepharospasm can occur as a standalone condition or as part of Meige syndrome. It is more common in women and often presents after age 50. Ocular surface disease or medications with movement effects can complicate the clinical picture.

Pathophysiology involves altered neural circuits in the basal ganglia and related motor networks, with impaired inhibition of excessive eyelid and facial movements. Neurochemical changes in GABAergic and other pathways are thought to contribute, though the exact cause remains unknown.

Diagnosis is clinical, based on history and examination, and by ruling out other causes of eyelid closure such as eyelid myokymia or severe eye irritation. The mainstay of treatment is injections of botulinum toxin into the affected eyelid muscles, which can substantially reduce spasms. Other options include oral medications (e.g., anticholinergics or benzodiazepines) and, for refractory cases, eyelid or facial muscle surgery. Prognosis varies, but with appropriate treatment many individuals achieve good symptom control.