Primary blepharospasm: diagnosis and management.

Primary blepharospasm is an adult-onset focal dystonia characterised by involuntary contractions of the orbicularis oculi muscles. Patients may have various types of movements arising from the different parts of the orbicularis oculi muscle. These include typical blepharospasm associated with Charcot's sign, pretarsal blepharospasm and flickering of the eyelids. Primary blepharospasm may be associated with so-called apraxia of eyelid opening as well as dystonia in the lower face, jaw or cervical muscles. Unless there are clinical clues to a symptomatic cause, adults presenting with blepharospasm do not require extensive aetiological investigation because the condition is rarely due to an identifiable condition. As the aetiology of primary blepharospasm is largely unknown, therapeutic approaches are symptomatic, with type A botulinum toxin being the treatment of choice.