Speaker 1: Welcome to brain Stuff, a production of I Heart Radio,
Speaker 1: Hey brain Stuff Lauren Bobi Bam here. The old saying
Speaker 1: sleep with one eye open isn't so metaphorical for everyone.
Speaker 1: Take for example, Mel mom in Kansas whom How to
Speaker 1: Work spoke with via email for the article that this
Speaker 1: episode is based on. Well, she has a son who
Speaker 1: regularly sleeps with both eyes about half open, and she said, oh,
Speaker 1: we joke around and say that Jack is afraid he's
Speaker 1: going to miss something. The family wasn't too weird a
Speaker 1: doubt when he started doing it, though, as they had
Speaker 1: experienced it with an older daughter. Mel said, a long
Speaker 1: time ago, we asked the doc. He said kids usually
Speaker 1: grow out of it. In her daughter's case, this wound
Speaker 1: up being true, but it's not unusual for people to
Speaker 1: sleep with an eye or two open indefinitely. The condition
Speaker 1: is known in medical circles as nocturnal lack ofthalmus, and
Speaker 1: is characterized by the inability to completely close the eyelids
Speaker 1: while sleeping. Most people are unaware that they're sleeping this
Speaker 1: way until someone tells them, but they may wake up
Speaker 1: feeling tired or experiencing eye pain. As much as of
Speaker 1: the population has experienced nocturnal lack of thalmus. It's a
Speaker 1: variation of the wider condition of lack of thalness, which
Speaker 1: describes any circumstance where you can't close your eyelids completely
Speaker 1: even when you're trying. It's usually caused by an improperly
Speaker 1: functioning seventh cranial nerve, the facial nerve that's responsible for
Speaker 1: the muscles that control the movement of both eyelids and eyebrows.
Speaker 1: That improper functioning can be triggered by a litany of issues,
Speaker 1: like trauma to the face or the skull, a thyroid disease, tumors,
Speaker 1: or damage from infections, among other things. Sometimes simple heredity
Speaker 1: is the culprit. Whatever the cause, it's unlikely that anyone
Speaker 1: is able to get good sleep with their eyes wide open.
Speaker 1: That's because your eyes need to close or at least blink,
Speaker 1: in order to keep your eyes lubricated and healthy. House
Speaker 1: of Works also spoke by email with Dr Ivan Schwab,
Speaker 1: a clinical spokesperson for the American Academy of Optimology. He explained,
Speaker 1: as far as I know, few people, if any, could
Speaker 1: sleep with their eyes fully open, because as you sleep,
Speaker 1: the upper lid muscles will relax and close, but if
Speaker 1: there were no upper lid coverage available, it might be possible,
Speaker 1: but would be difficult to sleep and quite detrimental to
Speaker 1: the eye with drying on the surface I surface drying
Speaker 1: is an uncomfortable problem that causes a burning sensation that
Speaker 1: may even wake you up in the middle of the night.
Speaker 1: This drying and irritation is called exposure carrotitis. If it
Speaker 1: becomes really problematic, there are options. The Schwab said the
Speaker 1: best way medically is to apply ointment and tape the
Speaker 1: lids closed, over that these measures must be done each night.
Speaker 1: In many, but not all cases, there are surgical options
Speaker 1: to raise the lower lid or lower the upper lid.
Speaker 1: There are also special eye goggles that can be worn
Speaker 1: at night to keep the eyes moist. However, although this
Speaker 1: is a problem in humans, a number of other animals
Speaker 1: evolutionarily developed the ability to sleep with one eye open.
Speaker 1: This is called un hemispheric sleep. Half the brain stays
Speaker 1: awake while the other half sleeps. Animals like fruit backs, porpoises,
Speaker 1: bottlenose dolphins, and birds are known to do this, likely
Speaker 1: because as potential prey, they need to be able to
Speaker 1: stay partially alert in order to stay safe. In these cases,
Speaker 1: the open eye blinks as normal so it doesn't dry
Speaker 1: out in today's episode is based on the article can
Speaker 1: You Fall Asleep with your Eyes Open? On how stuff
Speaker 1: Works dot com written by Leo Hoyt. A brain Stuff
Speaker 1: is production of I Heart Radio in partnership with how
Speaker 1: stuff Works dot Com, and it's produced by Tyler Klang.
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