The cause of blepharospasm is often unknown. It affects women more than men and tends to occur in families. It can sometimes be caused by other eye disorders such as trichiasis Trichiasis Trichiasis is misalignment of eyelashes, which rub against the eyeball, in a person who does not have entropion. Trichiasis develops most commonly some time after chronic blepharitis (inflammation... read more , foreign body in the eye Corneal Abrasions and Corneal Foreign Bodies Foreign bodies in the cornea cause abrasions, resulting in pain and redness, and lead to infections, even after they are removed. Most of these injuries are minor. (See also Overview of Eye... read more , dry eye Keratoconjunctivitis Sicca Keratoconjunctivitis sicca is dryness of the conjunctiva (the membrane that lines the eyelids and covers the white of the eye) and cornea (the clear layer in front of the iris and pupil). Too... read more 
, and sometimes by nervous system disorders such as Parkinson disease Parkinson Disease (PD) Parkinson disease is a slowly progressive degenerative disorder of specific areas of the brain. It is characterized by tremor when muscles are at rest (resting tremor), increased muscle tone... read more .
Symptoms of blepharospasm are uncontrolled blinking and closing of the eye. In severe cases, people cannot open their eyes. Spasms may be worsened by fatigue, bright light, and anxiety.
If blepharospasm is mild, it may be relieved by simple maneuvers such as singing, humming, touching an eyelid or chewing gum. Otherwise, treatment is injection of botulinum toxin A into the eye muscles, which can relieve or prevent the spasm. Drugs (to reduce anxiety) and sunglasses (to decrease light sensitivity) may help. If injection of botulinum toxin A does not help and symptoms are severe, surgery to cut the eyelid muscles can be done.
