Sleeping with your eyes partially or fully open is a recognized medical condition known as nocturnal lagophthalmos. This state often goes unnoticed by the affected person, typically only being observed by a partner or family member. It can lead to uncomfortable and potentially harmful effects on eye health. Understanding this condition, its causes, and its management is important for protecting the delicate surface of the eye.
Defining Nocturnal Lagophthalmos
Nocturnal lagophthalmos describes the inability to fully close the eyelids during sleep, leading to the exposure of the eye’s surface overnight. Estimates suggest that up to five percent of the adult population may be affected to some degree. The primary function of closing the eyelid is performed by the orbicularis oculi muscle, a circular structure around the eye. When this muscle contracts, it closes the eyelid, which is necessary for spreading the tear film across the cornea. Lagophthalmos results when this muscle or its controlling nerve fails to complete the closure. This condition can affect one eye or both eyes simultaneously.
Primary Reasons Eyes Remain Open
The underlying causes for the failure of complete eyelid closure are typically categorized into issues affecting the nerves, the eyelid structure, or external factors. A common cause is a problem with the facial nerve (the seventh cranial nerve), which controls the orbicularis oculi muscle. Damage to this nerve, such as from conditions like Bell’s palsy or a stroke, can cause paralysis that prevents the eyelid from shutting. Structural issues with the eyelid itself can also be responsible for lagophthalmos. Eyelid malpositions, such as ectropion, where the lower eyelid turns outward, physically prevent the lids from meeting. In some cases, the problem is iatrogenic, meaning it is a result of medical intervention, such as post-cosmetic surgeries like blepharoplasty. Factors like bulging eyes (exophthalmos), often associated with thyroid eye disease, can also make it physically difficult for the eyelids to cover the eye.
Consequences for Eye Health
The main danger posed by nocturnal lagophthalmos is the constant exposure of the eye’s surface to air, which causes rapid evaporation of the tear film. The tear film keeps the cornea moist and nourished, and its loss leads to drying and irritation. This exposure causes the common symptoms of morning dryness, grittiness, redness, and blurred vision upon waking. If the eye remains exposed for extended periods, the condition can progress to exposure keratopathy, which is damage to the outermost layer of the cornea. This superficial damage can lead to corneal abrasion (a scratch on the eye’s surface). The damaged corneal surface increases the risk of bacteria entering the eye, potentially leading to a severe infection or a corneal ulcer. In long-term cases, untreated corneal damage can result in scarring, which may lead to permanent vision impairment or vision loss.
Treatment and Management Strategies
The management of nocturnal lagophthalmos focuses on protecting the eye’s surface and addressing the underlying cause when possible. A primary step in non-surgical treatment involves enhancing lubrication to counteract the drying effect of exposure. This means using preservative-free artificial tears during the day and applying thicker lubricating ointments before bedtime to provide a protective barrier overnight. Mechanical protection is also an effective strategy for maintaining moisture and ensuring eye closure. Specialized moisture-chamber goggles or eye masks can be worn during sleep to create a humid microenvironment around the eyes. Another simple method is medical taping, where surgical tape is used to gently secure the upper eyelid to the lower eyelid before sleeping. For chronic or severe cases where the underlying cause cannot be reversed, surgical interventions are considered. One option is the placement of small gold or platinum weights into the upper eyelid, which uses gravity to assist the lid in closing completely. Another procedure, tarsorrhaphy, involves partially sewing the eyelids together to reduce the exposed surface area, protecting the cornea.