Let's blink in our dreams

Sleep with your eyes open?

Anyone who hears "You are sleeping with your eyes open" knows that they are not sleeping, but are not making an attentive impression. It is normal for us to close our eyes while sleeping. There are reasons we are doing this. But is it still possible to sleep with your eyes open?

When we are awake - open eyes protect themselves

To protect our eyes from drying out, we usually blink up to 20 times in 60 seconds during the waking hours. Every blink distributes tear fluid over the eye. This involuntary closing of the eyelids is called the blink reflex. It also prevents foreign objects from entering the eye.

When we sleep - this is how eyes protect themselves at night and when napping

We don't blink in sleep. The eye protection then works like this: fold down the eyelids, the cornea and the rest of the eyeball are safe. In this way the eyes do not dry out, nothing disruptive or injurious can get into them.

Healthy sleep - it should be dark

In order to sleep well, the body needs the hormone melatonin, which controls the sleep-wake cycle. It is formed and released in the pineal gland, but also, for example, in the retina of the eye and in the intestine in the dark. Incidence of light inhibits production. The light receptors in the retina of the eye act as messengers of the light message to the pineal gland. Closed eyes prevent the melatonin production from being disturbed by light.

Closed eyes - stimuli stay outside

With open eyes, images and impressions patter down on us - switching off is almost impossible. When we close our eyes, we set the switch for optical stimuli to "Off" and press the rest and relaxation button with the darkening.

Half-open eyes in sleep - it really does exist

Both children and adults go through different phases of sleep. The REM phase, in which we dream the most and most intensely, is characterized, among other things, by pronounced eye movements. The eyelids can open a little and even the pupils can be seen.

Or in some people one eyelid does not close completely, rarely both eyelids are affected. Doctors speak of lagophthalmos. The causes include nerve paralysis or paralysis, malformations and injuries to the eye muscles. Consequences of not closing the eyelids completely: A foreign body sensation in the eye, burning eyes, dry eyes or even inflammation. Treatment is usually with eye drops and ointments, in more severe cases surgically or, in the case of inflammation, with antibiotics.

Rarely: Eyelashes that are too thick prevent the eyes from closing completely.

Close your eyes, open your eyes - the animal world is rich in variety

Cat and dog sleep with their eyes closed. You have nothing to fear from your mistress and master. Likewise, cows, pigs, horses and rabbits close their eyes when they sleep.

But among the animals there are also eyes-on-sleepers. For example fish: they have no eyelids at all; you don't need them because the water will moisten your eyes anyway. For reasons of survival, other animals always have to "risk an eye" in the wild. After all, who can be on their guard with their eyes closed against voracious enemies or the pitfalls of living space? That's why nature has come up with a few tricks.

Take the dolphin, for example: the marine mammal sleeps with one eye open. It only switches one half of the brain to sleep. If both were inactive, his lungs would stop breathing - he would drown. The wakeful half of the brain regulates breathing, the dolphin swims with the awake half of the body. In the same way, one eye remains open - so the dolphin can keep an eye on its surroundings and can flee from danger. Other animals such as whales, seals, crocodiles, ducks, pigeons, chickens and other birds also sleep with one eye.

So there are different types of sleep: both eyes open, one-eyed, both eyes closed. We humans are among the eye-closers.

Discover more visual fairy tales and get to the bottom of visual myths. Or send us your own question now, simply by email or Facebook Messenger.

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