10/10/2025
EYELID MYOKYMIA
Eyelid myokymia is characterized by involuntary, fine, rippling contractions of the orbicularis oculi muscle, usually unilateral and more prominent in the lower eyelid. The contractions are spontaneous, continuous, and non-forceful, reflecting localized hyperexcitability of motor units within the facial nerve distribution. The condition is benign and self-limited, distinct from hemifacial spasm, which involves sustained, forceful contractions of multiple facial muscles due to aberrant facial nerve activity.
ETIOLOGY
The precise etiology of eyelid myokymia remains incompletely defined. Most cases are idiopathic, with no demonstrable structural or inflammatory lesion. Proposed mechanisms suggest transient hyperexcitability of the facial motor nucleus or its peripheral branches.
Predisposing or precipitating factors include:
•Physiologic stressors: emotional stress, anxiety, and fatigue.
•Lifestyle factors: sleep deprivation, excessive caffeine intake, and alcohol use.
•Drug-induced causes: uncommon associations have been reported with
Clozapine,
Flunarizine,
Topiramate,
Gold salts, and
In isolated reports, Metformin.
In rare cases, persistent or refractory myokymia may herald underlying demyelinating disease, brainstem glioma, or compressive facial nerve lesions, warranting further neurologic evaluation.
