[Essential blepharospasm: literature review].

Essential blepharospasm is a focal distonia characterized by involuntary, spasmodic, bilateral contractions of eyelid protractors. This is a rare disease, which diagnosis is frequently late and symptoms may progress until functional blindness. In this article, we perform a review and describe the most important features of the disease, including historical aspects, epidemiology, etiology, clinical findings, differential diagnosis and treatment.