The old saying "sleep with one eye open" is not so metaphorical for Robyn Cathey, of Acworth, Georgia. Three years ago, after many years' worth of normal sleep, Cathey started to occasionally doze with one or two eyelids ajar, a phenomenon that she attributes to the stressors of day-to-day life. "It happens when I'm super tired and I sleep really hard," she explains in an email.
Cathey isn't alone in the experience, either. Mel Boozer, of Andover, Kansas has a son who regularly sleeps with both eyes about half open. "We joke around and say that Jack is afraid he's going to miss something," she emails. She wasn't too weirded out when he started doing it, however, as she had experienced it with her older daughter. "A long time ago we asked the doc," she says. "He said kids usually grow out of it." In her daughter's case, this wound up being true, but it's not unusual for people to sleep with an eye or two open indefinitely.
The condition is known in medical circles as nocturnal lagophthalmos and is characterized by the inability to completely close the eyelids while sleeping. Most people are unaware that they're sleeping this way until someone tells them, but they may wake up feeling eye pain or tired.
As much as 20 percent of the population has experienced nocturnal lagophthalmos. It's a variation of the condition lagophthalmos — people who have this can never close their eyelids completely. It is usually caused by an improperly functioning seventh cranial nerve, the facial nerve that is responsible for the movement of both eyelids and eyebrows.
Lagophthalmos can be triggered by a litany of issues, like trauma to the face or skull, thyroid disease, damage to the eyelid or Bell's palsy, among others. Sometimes, simple heredity is the culprit.
Whatever the cause, it's highly unlikely that anyone is able to sleep eyes wide open, according to Dr. Ivan Schwab, clinical spokesperson for the American Academy of Ophthalmology in an email interview. "As far as I know, few people, if any, could sleep with their eyes fully open because as you sleep the upper lid muscles will relax and close," he says. "But if there were no upper lid coverage available, it might be possible but would be difficult to sleep and quite detrimental to the eye with drying on the surface."
Indeed, Cathey reports experiencing "extreme dry eyes that burn and wake me up in the middle of the night," and Boozer echoes the sentiment of her son. Dr. Schwab says that the drying and irritation of the conjunctiva is known as "exposure keratitis."
If it becomes really problematic, there are options. "The best way, medically, is to apply ointment and tape the lids closed over that. These measures must be done each night," Dr. Schwab says. "In many, but not all cases, there are surgical options to raise the lower lid or lower the upper lid." There are also special eye goggles to wear at night to keep the eyes moist.