Blepharospasm and hemifacial spasm refers to the abnormal, involuntary spasm of the muscles surrounding the eye or face. The exact cause remains unknown. The condition can be particularly disabling for some patients as they are unable to control the movement of their eyelids, face, or mouth. The condition may be less apparent or even absent during sleep. Recent advances in the use of Botox have proved extremely helpful for many patients with blepharospasm or hemifacial spasm. The impact of Botox results in reduced spasm of the affected muscles and provides temporary relief from the frequent muscle spasms. The effects of Botox may last for several weeks or even months. Some medications currently under investigation may be beneficial but tend to have unpredictable results. Medications tend to help only a small minority of patients. Currently the NIH is investigating new medications for the treatment of facial dystonia, such as blepharospasm and hemifacial spasm.