This refers to an involuntary spasmodic contraction of the orbicularis oculi muscle supplied by the facial nerve.
In addition to photosensitivity and increased tear production,blepharospasm will also accompany inflammation or irritation of the anteriorchamber. (Photosensitivity, epiphora, and blepharospasm form a triad ofreactive clinical symptoms.) Causes of the disorder include extrapyramidaldisease such as encephalitis or multiple sclerosis. Trigeminal neuralgia or psy-chogenic causes may also be present.
Clinical symptoms include spasmodically narrowed or closedpalpebral fissures and lowered eyebrows.
This depends on the cause of the disorder.Mild casescan be con-trolled well with muscle relaxants. Severe cases may require transection of the fibers of the facial nerve supplying the orbicularis oculi muscle. The disorder may also be successfully treated with repeated local injections of botulinum toxin.
The prognosis isgoodwhere acause-relatedtreatment is possible.Essential blepharospasm does not respond well to treatment.