Causes of Blepharospasm
Blepharospasm is primarily an idiopathic adult-onset focal dystonia with no identifiable cause in most cases, though it can be associated with specific medications, ocular surface disease, and rarely secondary neurological conditions. 1, 2
Primary (Idiopathic) Blepharospasm
The vast majority of blepharospasm cases are primary, meaning no specific etiology can be identified despite thorough evaluation. 1 The condition represents a multifactorial disorder where genetic susceptibility, epigenetic factors, and environmental triggers combine to reach a disease threshold, though the specific genes and triggers remain largely unknown. 2
- Primary blepharospasm is classified as an adult-onset focal dystonia characterized by involuntary contractions of the orbicularis oculi muscles. 1
- The pathophysiology involves dysfunction across multiple brain regions including the basal ganglia, cortex, and cerebellum, suggesting a network disorder rather than a single anatomical lesion. 3, 2
- Abnormalities in the basal ganglia dopamine system provide a sensorimotor learning substrate that, combined with patterns of increased blinking, leads to the abnormal motor manifestations. 4
Secondary Causes: Medication-Induced
Two specific medications have been clearly associated with blepharospasm and should be identified as potential causative agents:
- Dupilumab (used for atopic dermatitis) is associated with blepharitis and related ocular manifestations in 32% to 55% of patients, which can include blepharospasm-like symptoms. 5
- Isotretinoin (used for severe cystic acne) causes disruption in tear function and blepharitis, which may contribute to increased blinking and spasm. 5
Associated Ocular Surface Conditions
While not direct causes, several ocular surface conditions are frequently associated with blepharospasm and may represent comorbidities or contributing factors:
- Meibomian gland dysfunction and posterior blepharitis are commonly associated with increased blinking patterns that may contribute to the development of blepharospasm. 6
- Ocular surface disease, including dry eye disease and chronic blepharitis, can create sensory triggers that exacerbate involuntary eyelid movements. 5
- Essential blepharospasm is specifically mentioned as a comorbidity that should be addressed when managing neuropathic corneal pain. 5
Important Clinical Caveats
Adults presenting with blepharospasm do not require extensive etiological investigation unless there are specific clinical clues suggesting a symptomatic (secondary) cause. 1 The condition is rarely due to an identifiable underlying disorder in adults, making exhaustive workup unnecessary in typical presentations.
- The term "essential" in essential blepharospasm implies unknown cause, and patients may consult numerous providers seeking an explanation that often cannot be found. 7
- Blepharospasm should be distinguished from other conditions causing increased blinking or eyelid dysfunction, including apraxia of eyelid opening and lower facial dystonia, which may coexist with blepharospasm. 1