Facial palsy is paralysis of part of the face caused by non-functioning of the facial nerve that controls the muscles, especially around the eye and to the mouth. The facial nerve is also called the seventh cranial nerve.
It has a complex course from the brain stem to reach the muscles governing facial expression. It controls the muscles that lift the eyebrows, the muscles that close the eyelids, the muscles of the cheek and around the mouth.
Facial palsy can be congenital — present at birth or shortly after — or acquired, possibly following a viral illness or through no obvious cause. Under these circumstances, it is referred to as Bell’s palsy. Sometimes a tumour can compress and damage the nerve. Other causes include serious infections and skull fracture.
Facial paralysis usually affects half the face, which flattens and loses forehead wrinkles and horizontal lines. Other symptoms include a droopy eyebrow, difficulty closing the eye, an inability to whistle and the corner of the mouth being pulled down.
The effects on the eyes are particularly significant. The lower eyelid can sag and turn outward (ectropion), resulting in a watering eye, inability to close the eye and exposure or drying of the cornea. The eye can become red, vision can blur and sight is occasionally affected by ulceration and scarring (exposure keratopathy).
Rarely, patients may suffer a lack of sensation on the surface of the eye (cornea), so that they cannot feel dryness, foreign bodies or injuries to the surface of the eye. This puts them at risk of developing a corneal ulcer and suffering severe damage to their sight.
Crocodile tears are another rare consequence of facial nerve paralysis. They occur when the damaged nerve tries to grow back along its old pathway but goes instead to the tear (lacrimal) gland and to the muscles of the jaw. This results in embarrassing tears when the patients chews.
Other consequences of a nerve regrowing in the wrong direction include closing of the eyelid and muscle spasms in the eyelid, cheek and around the mouth.
Assessing Eye Health
Facial palsy can be graded as being mild, moderate or severe depending on how much the eyelids are able to close on blinking. If most of the eye is covered then the palsy is mild. If some of the eye can be covered on forced blinking, then the palsy is moderate. If the eyelids can cover none of the front of the eye during forced blinking, then the palsy is graded as being severe.
Initial Treatment for Corneal Exposure
Frequent instillation of artificial tear drops in the day time (at least every 2 hours) and lubricant ointment (e.g. Lacrilube) at night time.
If drops are needed more than 4 times a day then they should be PRESERVATIVE-FREE drops. Preservatives used in large quantities or over a prolonged period of time may damage the delicate cells on the surface of the eye or cause inflammation.
Ointment can be used in the day time also, but this does cause a lot of blurring of the vision.
Specific groups/types of lubricants include:
– Celluvisc, Optive
• Sodium Hyaluronate
– Hylotears, Hyalbak 0.15%
• Others, ie lipid polymers
– Ie Systane, Optive plus
• Carboxy methyl cellulose
– Hypromellose BP, Tears naturale
• Polyvinyl alcohol
– Liquifilm, Sno Tears, Hypotears
• Aqueous carbomer gels
– Viscotears, Artelac, Geltears
• Paraffin ointments
– Lacri-lube, simple eye ointment, xailin ointment (new and preservative-free)
If the eye does not close at night time, it can be taped shut. This can be difficult to do if the eyelid skin is greasy from ointment application. Cutting and applying cling film around the bones surrounding the eye creates a ‘moist chamber’ when sleeping. This helps to prevent the drying of the eye at night, and adds a little protection against damage caused by rubbing of the eye against the sheets or pillow. Consider a padded/cushioned night mask to help push the eyelid closed at night.
A temporary external weight may be applied to the eyelid skin to aid blink-closure in the day.
Glasses with visors or wraparounds should be worn for anyone with facial nerve weakness and incomplete eyelid closure.
I would also advise the use of air humidifiers at home and in the work-place.
It is very important to stretch both upper and lower eyelid skin early on after facial palsy as the skin may contract with time.
It is also important to improve eyelid margin meibomian gland dysfunction by carrying out daily hot compresses.
If lacrimal nerve is involved and eye is very dry then punctal plugs or permanent punctal occlusion is very helpful.
Corneal exposure can be treated surgically if conservative measures fail.
Aims of surgery of the eyelids are to:
As long as there is no damage to the eye from exposure, many doctors advise for the patient to wait 3 months before embarking on significant eyelid surgery to allow spontaneous recovery of the facial nerve.
Treatment is often in a staged approach. This is very useful as those with mild palsies require less complicated procedures and those with more severe palsies may require a greater number and complexity of eyelid operations.
Most patients with a permanent palsy will require additional help with eyelid closure in the form of eyelid surgery. The aims of surgery are to protect the front of the eye, to improve the function and position of the eyelids, improve cosmesis and reduce asymmetry between the two sides. However, as this is a lifelong problem, patients with a facial palsy may need multiple eyelid operations over time.
It’s important to remember to never remove skin in a patient with facial palsy (except in a brow lift).
I would advocate enhanced lower eyelid tightening surgery to improve eyelid closure. This may need repeating within a few years but is usually performed under local anaesthesia.
I would also recommend recession (weakening) of the eyelid retractors in order to elevate the lower eyelid and reduce upper eyelid retraction and improve eyelid closure.
Upper eyelid lowering – for improved closure
Upper eyelid loading with weights improve eyelid blink and closure. This nowadays carried out with platinum weights. The weight allows the eyelid to blink.
Benefits include: can improve cosmetic appearance, improved protection of the cornea, reduced pain caused by dry eye. Problems include: poorly placed or bulky weight may be less aesthetically pleasing, the weight may be rejected by the eyelid, astigmatism risks.
Drooping of the brow
Can be improved by excising some of the forehead skin above the eyebrow (via a cut in the skin just above the eyebrow hairs). Over time the brow may drop again due to the effect of lack of tone in the forehead muscle and the effect of gravity.
Occasionally, the front of the eye (cornea) becomes ulcerated and very painful, or the eye becomes red. This condition is known as exposure keratopathy with severe keratitis. Lubricants and other eye drops may not be enough to improve this condition, so it can be necessary to lower the upper eyelid temporarily.
This is done by giving a small injection of Botox underneath the upper eyelid, which temporarily paralyses the muscle that lifts the eyelid open and allows the eyelid to drop over the eye (protective ptosis) so that the keratitis or ulcer can heal. These injections can last up to three months and be repeated. Alternatively, surgery may be needed.
Botox can also be injected into the tear (lacrimal) gland to prevent crocodile tears and to deal with tics caused by the facial nerve regrowing in the wrong direction.