Hemifacial spasm is a condition where the muscles of one side of the face twitch involuntarily.
Blepharospasm is a condition where both eyes blink excessively.
Hemifacial spasm occurs due to injury to the facial nerve that controls facial movement. Tumors, trauma, or Bells palsy may cause the initial injury. After recovery, the facial nerve may not heal completely, and it sends abnormal signals to the muscles. There is no direct cure for this nerve injury, but the twitching of the muscles may be dampened significantly by the use of botulinum toxin, also called Botox or Xeomin. Sometimes the muscles that close the eye are so tight that it is difficult to read or see. Injections of botulinum carefully applied around the eye can relax the eyelids and open the eye.
Blepharospasm is a condition where the eyelid closing muscles blink too fast and too strong. Both eyes are affected. This is caused by abnormal brain signals that send incorrect messages to the eyelids. Sometimes the eyes clamp shut and are unable to be opened at all, for several seconds at a time, making certain activities very dangerous, like driving. Oral medications are not generally helpful. The most effective treatment is botulinum toxin injections, which are carefully applied around the eyes to relax the muscle spasms.