lagophthalmos

thumb|An example of nocturnal lagophthalmos Lagophthalmos is an inability to close the eyes while sleeping.

Blinking covers the eye with a thin layer of tear fluid, thereby promoting a moist environment necessary for the cells of the exterior part of the eye. The tears also flush out foreign bodies and wash them away, which is crucial to maintain lubrication and proper eye health. If this process is impaired, as in lagophthalmos, the eye can suffer abrasions and infections; thus leading to corneal drying and ulceration.