Blepharospasm involves involuntary contraction of the eyelids and is also referred to as benign essential blepharospasm (BEB). The spectrum of symptoms in BEB is widely variable and the mildest form may involve a slight increase in blink rate or intermittent twitching. In the most severe forms BEB can result in more disabling symptoms such as the inability to open the eyes, ache around the eyes and a reduction in vision.
BEB is found in approximately 5 per 100,000 population and is more commonly found in females. Most patients are over the age of 60 years.
The cause of BEB is poorly understood and is felt to be secondary to a dysfunction in the ‘circuit regulation’ of nerves providing ocular sensation and movement of the eyelid.
BEB is associated with dry eye and symptoms can be increased in certain situations including wind, pollution and stress.
Common symptoms include:
- Ocular discomfort in bright lights (photophobia)
- Increased blink rates
- Twitching or involuntary movements of the eyelids. This may start on one side of the face and spread to both sides with time.
- Dry eye symptoms (grittiness and redness of the eyes)
- Spasm of the eyebrow
Certain actions can improve BEB which can aid in the diagnosis. These include sleep, reduction in stress, occlusion of vision of the affected eye, ocular lubricants, talking and humming.
No cure currently exists for BEB and treatments are mainly aimed at alleviating symptoms.
Conservative measures include:
- Ocular lubrication
- Tinted lenses on spectacles (FL-41 tints)
- Eyelid hygiene
The mainstay of treatment is the application of Botulinum A toxin. This is otherwise known as Botox® or Dysport®. Botulinum A Toxin provides temporary reduction in the eyelid spasm and has good success rates. The toxin is produced by a bacteria (Clostridium botulinum) and causes paralysis of muscle by blocking the neural input to muscle.
Botulinum A toxin is applied using injections around the eyelids in clinic. Depending on the manufacturer the treatment will take between 2-7 days to take effect and may provide symptomatic relief last for 2-3 months at which point repeat injections are applied. In some cases the effects may last for more or less time.
In cases of BEB associated with dry eye, surgery may be aimed at improving the ocular surface. Minor procedures including occlusion of the tear duct may help to reduce dry eye and BEB.
In severe cases whereby BEB is not responsive to medical treatment more radical surgery may be indicated. This includes surgery to excise the muscle that causes the eyelid to close (orbiculectomy).
Author: Mr Jonathan Norris FRCOphth