Stretch reflex blepharospasm.
We studied a patient with blepharospasm provoked by stretching the orbicularis oculi muscles. With the eyes closed, EMG of the orbicularis oculi at rest revealed spontaneous rhythmic muscle activity that was not visible. When she tried to open her eyes, repetitive jerking blepharoclonus and tonic blepharospasm rendered her functionally blind. Passive stretching of the orbicularis oculi evoked a burst of EMG activity with two components. Touch or pinprick did not elicit such reflex activity. Anesthesia of the supraorbital nerves abolished muscle responses to stretch and improved the blepharospasm.
D000368:Aged; D001764:Blepharospasm / Q000503:physiopathology*; D001767:Blinking; D004576:Electromyography; D005123:Eye / Q000503:physiopathology; D005141:Eyelid Diseases / Q000503:physiopathology*; D005260:Female; D006801:Humans; D009132:Muscles / Q000503:physiopathology*; D012026:Reflex, Stretch