Who Sleeps with One Eye Open?

Do you ever feel like you're not getting enough sleep? You're not alone. It turns out that 20% of people actually sleep with one eye open! This phenomenon is known as unihemispheric sleep, where half of the brain is awake while the other half is asleep. This evolutionary trick allows animals to stay alert and keep one eye open for potential danger. Bottlenose dolphins are known to turn off half their brain and keep the other half ready while they sleep.

The eye on the side of the body that controls the awake hemisphere of the brain can remain open during sleep. Humans also slip into unihemispheric sleep when they find themselves in new or unfamiliar situations. Crocodiles, who have almost no known predators, also sleep with one eye open. The Amazonian manatee, the second smallest of its species, is another aquatic mammal that employs unihemispheric sleep.

Thyroid problems can also cause people to sleep with their eyes open. If you find yourself with restless sleep, dryness or irritation in your eyes, consult your doctor to find the right treatment options for you. In some cases, surgery may be recommended to tighten the levator muscle or attach the eyelid to other muscles that can help lift it. It's important to note that there are a variety of medical conditions that can make it impossible to close your eyes while sleeping.

Without sufficient lubrication, the eyes are more susceptible to infection and can become scratched and damaged. So if you find yourself sleeping with one eye open, it's best to consult a doctor for proper diagnosis and treatment.