Blepharospasm
What is Blepharospasm?
Blepharospasm is a localised movement disorder (focal dystonia) that affects the muscles that control eyelid movement. The disorder is characterised by increased blinking caused by involuntary spasms of the muscles controlling the eyelid. Blepharospasm usually affects both eyelids and can progress to functional blindness (i.e., an inability to open the eyelids for any significant period of time).
Approximately 75% of patients with blepharospasm are female and the average age at onset is 56 years. Although the exact cause of this disorder is unknown, experts believe that it may be caused by a defect in the basal ganglia-a group of nerve cells in the central nervous system.
How is Blepharospasm treated?
Through the use of neurotoxins injected directly in the affected eye muscles which relieves the muscle spasm. The duration of effect lasts approximately three months, at which time the neurotoxin can be re-injected as long as the patient continues to respond and does not have a serious allergic reaction.
Reduced blinking from neurotoxin injection of the orbicularis muscle can lead to corneal exposure, persistent epithelial defect and corneal ulceration; especially in patients with VII nerve disorders. The effects of therapy may be increased with the use of aminoglycoside antibiotics or with other drugs that interfere with neuromuscular transmission.
Some noted side effects of neurotoxin injections noted from prior clinical studies, in decreasing order of incidence, include irritation, tearing, lagophthalmos, photophobia, entropion, keratitis, diplopia, diffuse skin rash and local swelling of the eyelid skin lasting for several days following eyelid injection.