Botulinum-Induced Changes in Orbicularis Oculi Muscle

ABSTRACT

A 60-year-old woman who had essential blepharospasm was treated with botulinum toxin A (two injections) around her orbital regions. The patient experienced reduction of blepharospsam for one month. But involutional blepharoptosis, brow ptosis and dermatochalasis had remained, so she underwent blepharoplasty. The resected orbicularis muscle during blepharoplasty was examined histopathologically. It was suggested that nonselective atrophy of the orbicularis muscles was derived from the loss of the normal neurotrophic influence of nerve on muscle by the botulinum toxin A.