What is blepharospasm?
The muscles around the eyelid can be affected by a wide range of movement complaints. The most common disorders are Benign Essential Blepharospasm and Hemifacial Spasms. So, let’s take a look at these in more detail.
Benign Essential Blepharospasm describes an involuntary closure of the eyes. It can present itself as rapid and frequent blinking, forced eyelid closure or an inability to initiate eyelid opening (apraxia of eyelid opening). Often, it can be a combination of these different manifestations of the condition.
It can be a disabling condition which can go onto affect other facial muscles. In fact, 30% of patients experience involuntary tongue, mouth and neck movements.
This can give the appearance of lip and mouth movements or tongue and jaw spasm. The condition can have a significant impact on an individual’s vision and, occasionally, the muscles of the larynx (voice-box) can become affected, producing a hoarse or whispering voice.
There is, unfortunately, no cure for the condition but there are many treatment options available. With the right combination of medical and surgical treatments, the vast majority of patients go on to regain normal functioning of the eye and face muscles.
What causes blepharospasm?
The causes of blepharospasm are complex. There is definitely a genetic predisposition which has been identified and many patients will report a family history, including chronic irritation of the eyes. This is usually in the form of blepharitis or dry eyes. It is thought that chronic eye irritation can induce a maladaptive reflex response, allowing the normal protective blinking reflex to assume a life of its own and overwhelm the normal functioning of the blink reflex.
Our recent research at Moorfields Eye Hospital in London has also shown that blepharospasm patients have an underlying abnormality in the nerve layer of the corneal epithelium and associated decreased sensitivity of the ocular surface. Similar sensory abnormalities have been identified in other dystonias, neurological movement disorders ibn which sustained or repetitive muscle contractions result in twisting or abnormal fixed postures. This suggests that decreased sensory stimulation to the brain can cause and input/output mismatch precipitating dystonia.
Confocal microscopy of the corneal nerve plexus demonstrating abnormalities in patients with blepharopsasm compared with controls.
How is blepharospasm treated?
It is essential that patients are treated in a centre which has specific expertise in the management of the condition. Daniel Ezra practices at the internationally renowned Moorfields Eye Hospital. This is considered to be a centre of excellence in the treatment of Blepharospasm with several hundred patients being treated per year.
The first step in treating blepharospasm is to identify and eliminate any cause for ocular surface irritation. This will be carried out using a full slit lamp biomicroscope examination. This is important because conditions causing irritation of the eye are usually either dry-eye or blepharitis, but they can also include Sjorgren’s syndrome, thyroid eye disease and herpetic keratopathy.
The following method is to then carefully inject BoNT into the overacting muscle groups. All patients will have different patterns of spasm and so the injection programme is tailored to each individual. Most patients will get significant relief from BoNT therapy. In addition, if you are found to have a brow ptosis (droop), excess upper eyelid skin or a droopy eyelid, surgery will usually be needed to correct them.
Is BoNT treatment safe?
The treatment is perfectly safe and there is no risk of developing botulism or food poisoning. Based on the experience of treating thousands of patients (in over three decades at Moorfields Hospital) we are also confident that there is also no risk of developing general health problems after administration. What’s more, there is no known risk when the treatment is given to women who are pregnant or breastfeeding although some do prefer to postpone treatment until they have given birth or weaned their children.
I have tried BoNT, but it is not working, what else can I do?
Sometimes BoNT treatment is not successful. This can occur initially or after many years of successful use when the patient develops a resistance to the drug. Fortunately, there are many other approaches to consider:
- Changing the type of otulinum toxin. Incorporating different formulations can be used to overcome resistance to a particular strain. There are also new variants that have been proven to be effective. These include BoNT and BoNT.
- Oral medications. There are several types of treatments which act directly of the brain and you may be asked to try these medications to determine if they are effective.
- Blepharoplasty surgery to remove excess upper eyelid skin and muscle
- Orbicularis myectomy involves the targeted removal of muscle fibres closest to the eyelid margin, this can have the effect of weakening the eyelid closure muscles.
- Brow suspension surgery is particularly effective for patients with apraxia of eyelid opening and involves internal suspension of the eyelid unit to the brow. This can be a very effective treatment in the appropriate patient group
- Patients with facial nerve paralysis can also benefit from BoNT therapy. It can alleviate twitching caused by misfiring of the nerve, often called 'aberrant innervation'. BoNT can also be extremely effective in restoring or improving facial symmetry by targeting overactive muscles of the face. Mr Ezra is the clinical lead for the BoNT service at Moorfields and has extensive experience at treating all of these conditions.
Scanning electron microscope images of different types of brow suspension materials