Hemifacial spasm describes the persistent, involuntary contraction of facial muscles on one side of the face. Blepharospasm pertains to chronic eyelid twitching. These conditions can occur due to a blood vessel pressing near the nerves that control the face or eyelid muscle, or after trauma, resulting in injury to the nerves. They can also be idiopathic (no identifiable cause) which is more common in females between the ages of 40-60. Depending on the severity and chronicity of the condition, hemifacial and blepharospasms can impact daily activities such as reading, socialising or driving.  

One possible treatment is Botox injections into the affected muscles which temporarily paralyse them and prevent them from contracting involuntarily. The effect of Botox injections usually last between 3-4 months.