Blepharospasm 

Blepharospasm is a disorder of the muscles that control eyelid movement. Spasms of the eyelid lead to frequent blinking. Blepharospasm often affects both eyelids, making it difficult to open the eyelids. In severe cases, this debilitating condition can lead to what is known as "functional blindness" because the patient is unable to open or keep 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.1 Although the exact cause of this disorder is unknown, experts believe that it may be caused by an inappropriate signal in the part of the brain known as the basal ganglia.2

Doctors diagnose blepharospasm based on key signs and symptoms. In the early stages of blepharospasm, patients may complain of irritation and discomfort of the eyelids as well as an increase in blinking. As the blepharospasm progresses over two years, blinking usually becomes more frequent, forceful, and uncontrollable. Bright, dazzling, or flickering lights, dusty or smoky air, or high-speed travel by train or car can make the symptoms worse. Without proper medical treatment, most patients with blepharospasm do not recover.

When injected directly in the affected eye muscles, the neurotoxin relieves the muscle spasm. Although the effect is temporary, BOTOX® can be reinjected approximately every three months as long as the patient continues to respond and does not have a serious allergic reaction.3

Reduced blinking from BOTOX® 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.

The most frequently reported adverse events associated with BOTOX® include ptosis (20.8%), superficial punctate keratitis (6.3%), and eye dryness (6.3%).4 Other events reported in 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.

As with any treatment that may result in resumption of activities by previously sedentary patients, sedentary patients should be cautioned to resume activity gradually following the administration of BOTOX®.3 In general, adverse events occur within the first week following injection of BOTOX® and while generally transient may have a duration of several months. Localized pain, tenderness and/or bruising may be associated with the injection. Local weakness of the injected muscle(s) represents the expected pharmacological action of botulinum toxin. However, weakness of adjacent muscles may also occur due to spread of toxin.

1. Henderson JW. Essential blepharospasm. Trans Am Ophthalmol Soc. 1956;54:453-520. 
2. Dystonia Medical Research Foundation. Available at: http://www.dystonia-foundation.org/. Accessed January 12, 2001. 
3. BOTOX® Full Prescribing Information. 
4. Data on file, Allergan, Inc. 1997.