Essential blepharospasm

Specialty: Ophthalmology.

• involuntary eyelid spasm
• eyelid tic
• bilateral uncontrollable blinking

Why it occurs

• Benign essential blepharospasm (idiopathic focal neurological dystonia affecting the orbicularis muscles)
• Meige syndrome (segmental dystonia combining bilateral blepharospasm with oromandibular and cervical muscle spasms)
• Secondary or reflex blepharospasm due to irritative ocular pathology (severe dry eye, superficial keratopathy, anterior uveitis)
• Extrapyramidal effects induced by neuroleptic drugs or dopaminergic antiemetics
• Facial hemiespasm (of unilateral origin due to microvascular compression of the facial nerve)

Initial workup

Comprehensive neurological and ophthalmological physical examination; Biomicroscopy of the anterior pole to rigorously rule out factors causing subtle ocular pain or underlying keratitis; Schirmer test and corneal staining; Eyelid electromyography in doubtful cases; Magnetic resonance imaging (MRI) of the posterior fossa with fine MR angio-MRI sequences of the posterior fossa if there is suspicion of neurovascular compression in unilateral facial hemispasm.

Standard management

• Botulinum toxin type A — selective intramuscular injections of 1.25 to 5 units per point in the orbicularis oculi muscle, corrugator intereccles and procerus muscle, applied every 12-16 weeks; It is the first-line treatment of choice for essential blepharospasm.
• Clonazepam — 0.5 mg to 2 mg orally per day as a GABAergic modulator adjuvant, with moderate response
• Trihexyphenidyl (anticholinergic, 2 to 6 mg orally per day in cases with diffuse dystonic component refractory to botulinum toxin).