Nocturnal lagophthalmos

Nocturnal lagophthalmos is the inability to close the eyelids during sleep. It may reduce the quality of sleep, cause exposure-related symptoms, or, if severe, cause corneal damage (exposure keratopathy). The degree of lagophthalmos can be minor (obscure lagophthalmos), or quite obvious.

It is often caused by an anomaly of the eyelid that prevents full closure. Treatment may involve surgery to correct the malposition of the eyelid(s). Punctal plugs may be used to increase the amount of lubrication on the surface of the eyeball by blocking some of the tear drainage ducts. Eye drops may also be used to provide additional lubrication or encourage the eyes to increase tear production.

The condition is not widely understood; in at least one instance a passenger was removed from a US Airways flight because of it.