Hemifacial spasm (HFS) is a condition that causes involuntary contractions of the muscles on one side of the face. The disorder occurs in both men and women, usually beginning in middle age. Symptoms often begin as a twitching of the eyelid and may gradually spread to involve the muscles of the lower face. The condition may be caused by a blood vessel pressing on a facial nerve, a facial nerve injury, or a tumor, or it may have no apparent cause.
After your ophthalmologist (Eye M.D.) has ruled out other more serious underlying conditions, the most common treatment for HFS is the injection of botulinum toxin, a neurotoxin, into the affected muscles. In some cases, surgery may be necessary.
If botulinum toxin is the best treatment for your condition, your ophthalmologist will inject the drug into the involved facial muscles in a simple, outpatient procedure. Botulinum toxin has proven to be a safe treatment for HFS with few side effects. The injections will probably work for about six months, so repeated treatments are necessary. You should see the full effect of the injection about a week after the procedure.