Lagophthalmos is a condition in which the eyelids do not close completely. This prevents complete closure during blinking as well as during sleep.
Blinking is essential to keeping the eyes properly moist, as it facilitates moistening/lubrication of the conjunctiva and cornea, on the outside of the eyeball. Tears also flush out foreign particles and so prevent inflammation. The inability to blink can lead to drying out of the surface of the eye, and eye infections.
Lagophthalmos is most often caused by facial nerve paralysis, but can also have several other causes. Lagophthalmos, if left untreated, can cause corneal exposure (keratitis), ocular perforation or perhaps even the loss of an eye.
What are the different types of lagophthalmos?
Paralytic lagophthalmos is the most common form and is caused by facial nerve paralysis. Up to 80% of all facial nerve paralysis are caused by Bell’s palsy. Bell’s palsy is a short-term (acute) unilateral facial nerve paralysis disorder with unknown causes. Patients also suffer from deafness, alteration of taste and numbness of a cheek on one side (usually).
Facial nerve paralysis could also be associated with trauma such as temporal bone fracture during surgery (e.g. parotid gland surgery or brown-lift surgery). Other causes of facial nerve paralysis include infections such as HIV, Lyme disease, measles, polio and herpes zoster virus (Ramsay-Hunt syndrome). Finally, certain tumors may also cause facial nerve paralysis, such as tumors of the facial nerve, acoustic neuromas or metastases from systemic cancers.
Cicatricial lagophthalmosis the result of scarring following a trauma or surgery. The formation of excessive scarring leads to disfiguration of the eyelid, and prevents normal closure. Such cases may include chemical burns, lacerations, or chronic conditions like xeroderma pigmentosum, which is a rare skin disorder that renders the individual ultra-sensitive to sunlight/UV.
Nocturnal lagophthalmosis a condition in which the eyes remain fully or partially open during sleep. Unlike a constant inability to close the eyelids both during the day and night, this condition only occurs during sleep. As a consequence, patients often suffer from insomnia and feel significant discomfort related to their eyes upon waking.
Are there any treatments for lagophthalmos?
In the treatment of lagophthalmos, the main aim is to prevent exposure keratitis (inflammation of the cornea) as well as trying to re-establish eyelid function.
The first treatment strategy is usually to keep the eyes hydrated. Blinking normally prevents dryness by spreading the tear film and Meibomian gland secretion over the surface of the conjunctiva and cornea. As patients with lagophthalmos cannot blink normallyl, ophthalmic ointment or lubricating eye drops are usually applied both during the day and the night. In extreme cases, taping the eyelid shut, and using a moist chamber to prevent drying out of the surface of the eyeball, might solve extreme dryness. If the condition is acute, lid levator injections of botulinum toxin can allow for better occlusion of the eye.
Permanent treatments will often target the paralyzed facial nerve. For example, facial nerve repair, or cross-facial nerve grafting, can restore eyelid muscle function and also help re-establish facial symmetry. These procedures are typically not used in older patients.
If conventional surgical procedures fail to improve the condition, a second choice is a procedure known as tarsorrhaphy. This includes sewing the eyelids together partially, to narrow the eyelid opening. Other similar techniques such as lid loading involves placing a small weight on the upper eyelid, thus increasing the downward pull on it so that this will gradually cause closing of the eye when forced to close. The weight is light, being just sufficient to experience a gravitational pull, and is often made from gold.
In summary, lagophthalmos is most often caused by facial nerve paralysis and often has a good recovery rate if treated promptly. Understanding the cause is essential to determining what treatment strategy will offer the best success rate. Treating the underlying condition should improve facial nerve function and cosmetic appearance, although unfortunately, there are some conditions where this may be difficult.