A blepharospasm is the involuntary closing of the eyelids. It happens because of involuntary contractions of the orbiculus oculi (the muscle responsible for closing the eyelids). It is one of the most common dystonias (abnormal movements) affecting the head and neck.

An essential or primary blepharospasm is bilateral and may be accompanied by involuntary movements of the neck, mouth, head or mouth that only disappear whenever the patient is sleeping. It is a process that usually progresses gradually, increasing slowly in intensity and frequency.

The main symptoms of blepharospasm are incontrollable blinking at the start, involuntary closing of the eyes and even reduced vision in serious cases due to the inability to open the eyes, sensitivity to light (photophobia) and dry eyes. The symptoms start progressively, but the pathology advances gradually in both frequency and intensity. 

Patients may have trouble doing daily activities as the symptoms can appear suddenly and at any time. 

The causes of blepharospasm may be secondary to disorders of the central nervous system and to the lack of lubrication on the surface of the eye—which increases the frequency of blinking in an attempt to stop the eye watering—, the side effects of certain medications and patients with hemifacial spasms. 

There are three types:

• Minor eyelid twitch or tic is like a blink of the eyelid or a vibration. It is usually related to stress, a lack of sleep or high consumption of caffeine. It does not usually require treatment and normally goes away by itself. 
• Benign essential blepharospasm is a disorder that normally affects both eyes and causes involuntary, intense and chronic closing of the eyes. Its intensity and frequency usually increases over time if it is not treated it and it can end up incapacitating. 
• Hemifacial spasm in which the muscles on one side of the face are affected causing irregular and gradual involuntary movements that may affect the orbicularis oculi, the muscles around the mouth and the front muscle, etc. It may be caused by compression of the facial nerve because of an artery or a trauma. 

Blepharospasm cannot be prevented, but early detection is important. In many cases, blepharospasm is associated with an eye problem when it is actually a neurological problem.

Treatment involves eye protection using glasses with specific filters, lubricating eyedrops and the application of botulinum toxin (a substance injected into the affected muscles to relax them temporarily, preventing them from contracting). The effect of the injections is temporary and typically lasts for a few months, which is why, to maintain the effect, you have to repeat the treatment. 

Although its efficacy is very high, in very aggressive cases we can resort to a surgical procedure in which part of the ocularis oculi and the depressor muscle are removed to prevent the eye from closing involuntarily. After surgery, at times further botulinum toxin infiltrations are required.