Blepharospasm – eyewiki gas 10 ethanol

####

Blepharospasm is involuntary closure of both eyelids. Benign essential blepharospasm (BEB) is a bilateral condition and a form of focal dystonia characterized by episodic contraction of the eyelid protractor muscles (orbicularis oculi, procerus, and corrugator superciliaris) and is not associated with another disease. BEB needs to be differentiated from blepharospasm that can exist as part of a specific syndrome (ie Meige syndrome) or systemic disease (ie extrapyramidal disorders) and that which occurs secondary to ocular irritation and medication.

The mechanism underlying benign essential blepharospasm is not yet clearly understood. Basal ganglia dysfunction, overactivity of the seventh nerve leading to simultaneous forceful contractions of the eyelid protractors and retractors, ion channelopathy, and sensitization of the trigeminal system by photophobia are some of the proposed mechanisms.

There is no known method to prevent benign essential blepharospam. In cases of secondary blepharospasm, avoiding the inciting irritant (ie bright light), treating the underlying disease (ie blepharitis, dry eye), decreasing stress or the dose of the causal medication may reduce symptoms.

History is very important in making the diagnosis, and it also allows the clinician to distinguish between primary (essential) and secondary blepharospasm. In BEB, excessive blinking, which may start as unilateral and mild twitches, progresses to bilateral frequent and more forceful spasms. During severe episodes a patient may report the inability to pry the eyelids open. Episodes may interfere with the patient’s daily activities, such as reading and driving. The spasms disappear during sleep and may be reduced when concentrating on a specific task. In secondary etiologies, the patient may offer a history of drug use as with tardive dyskinesia, of ocular irritation from light or dry eye as in reflex blepharospasm, of associated facial grimacing as in Meige syndrome, or a history of other abnormal movements such as tics or cogwheeling of the neck and extremities in extrapyramidal disease states.

The physician may observe involuntary contraction of multiple eyelid muscles (both protractors and retractors) during a spasm episode. Careful slit lamp examination for ocular causes and inspection for other twitches in the face or extremities must be undertaken.

Signs and symptoms in benign essential blepharospasm are limited to the bilateral eyelids. They usually begin as mild and infrequent twitches that progress over time to forceful and frequent spasms of the eyelids, which abate during periods of sleep. In advanced cases, these episodes can cause functional blindness from periodic inability to open the eyes. This can severely limit the patient’s ability to preform activities of daily living and impart psychological stress. When blepharospasm is part of Meige’s syndrome, it is associated with facial grimacing. Reflex blepharospasm may be accompanied by photophobia and ocular signs of blepharitis and surface disease.

• Oral medications such as muscle relaxants and sedatives are rarely effective in the treatment of BEB. They may dampen symptoms of mild BEB or possibly prolong intervals between injections, but their side effects must be considered alongside their benefits.

Surgery is reserved for patients who are poorly responsive to botulinum therapy and are disabled by their symptoms. Patients with apraxia of eyelid opening may often proceed to surgery as chemodenervation with botulinum toxin is less effective. Surgical myectomy of the orbital and palpebral orbicularis muscle in the upper (and sometimes lower) eyelids as well as surgical ablation of the facial nerve are effective in treating BEB. However, the latter procedure has been mostly abandoned owing to high recurrence rates incidence of hemifacial paralysis.

Symptoms of BEB can progress to render a person incapable of activities of daily living, such as reading and driving, and cause an unwanted cosmetic effect. The psychological distress is a real part of the disease and patient education, counseling, and support is as valuable as medical treatment.

• Defazio G, Martino D, Abbruzzese G, et al. Influence of cigarette smoking and coffee drinking on the risk of primary late onset blepharospasm: evidence from a multicenter case control study. J Neurol Neurosurg Psychiatry. 2007;78(8):877-879.