Why Does My Dog Sleep With His Eyes Open? (When To Worry)

Why Does My Dog Sleep With His Eyes Open? Photo of a dog sleeping with eyes open.

If you’ve had glanced over at your dog when he’s fast asleep to find that his eyes are open, it may have frightened you! Curious as to what’s going on? Here’s what you need to know!

Dogs often appear to sleep with their eyes open, but this is not really the case; it just appears that way to us!  This normal behavior is explained by a dog’s third eyelid, which covers its eye and protects it from dirt and bacteria.

It is a trick that dogs have learned throughout the evolution to trick predators into thinking they are still awake (and watching) and remain alert so that they can react to a sound, smell, or something similar as soon as they register it.

Why do dogs have their eyes open when they sleep?

In the modern-day, there is no need for dogs to sleep with their eyes open, but this is normal behavior that is part of their lizard brain. Dogs often will appear to sleep with their eyes open because they’re genuinely asleep. A dog sleeping with their eyes partially open is often in REM sleep or deep sleep.

Think of it this way: a dog’s sleep pattern is similar to humans. At first, their short-wave or slow-wave sleep is characterized by their slowing breathing and slowing heart rate. Their eyelids will drop closed as they settle in.

Once they are truly asleep, their heart rate will pick up, their eyes will twitch (along with a paw or tail, at times), which can also mean that their eyes will open. Sleeping with their eyes open is a sign that they are sleeping soundly and resting up.

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Why does my dog sleep with his eyes open?

There are several reasons, technically, for this natural behavior. The actual reason could be a combination of these things, or it could be just one reason. The most popular ones include:

  • Protection from predators
  • You’re seeing their third eyelid
  • They’re dreaming
  • They have Cherry Eye
  • They have Lagophthalmos
  • They are narcoleptic

Protection from predators

As far as their lizard brains are concerned, danger is everywhere. Dogs have evolved to sleep with their eyes slightly open so that they can still see something as soon as they are conscious. This means that they can remain on alert even when they sleep.

As well, even though it’s creepy to us, dogs sleeping with their eyes open gives predators the sense that they are still watching them. That is, predators have no way to know for sure that your dog is asleep, so they’ll go somewhere else instead to steal food, etc. 

You’re seeing their third eyelid

Another explanation is that their eye is actually closed, and you’re seeing their third eyelid. This is a thin membrane that is light brown but often appears to be clear. It will give the appearance of their eye being partially open since it will flick up over the eye as your dog’s eyes partially close/open. 

They’re dreaming

Dogs dream in REM sleep, just like humans do. This means that their eyes will twitch, as well as their legs and paws. As they relax into the dream, their eyes will open, and their eyes may even flick back and forth. Humans do this, too, but our eyes don’t open enough for anyone to notice.

They have Cherry Eye

Some breeds are prone to conditions called Cherry Eye. This is when there is irritation in a dog’s third eyelid, and it swells up to form a nodule in the corner of the eye. As it heals, this will go back to normal, but it will take time. While dealing with a flare-up, the dog’s eyes will appear to be open since they can’t close all the way with the inflammation in place!

They have Lagophthalmos

This is a scary condition that is common, especially in aging dogs. This is when the eye has swelled due to a condition such as glaucoma. This swelling/pressure increase means they cannot close their eyes since the eyelid is not spanned enough. 

They are narcoleptic

Narcolepsy is a rare condition in dogs, but it can happen. While playing, your dog will suddenly fall fast asleep right in the middle of whatever it is they’re doing. This switch to “sleep mode” is so fast that their eyes may not close all the way, even as they’re snoring. 

Is it common for dogs to sleep with their eyes open?

Yes, it is very common for many dogs — who are perfectly healthy, we might add — to sleep with their eyes open. It’s just not something that humans are aware of all of the time until they happen to witness it for themselves and feel a wave of panic. Some dogs may never sleep with their eyes open, and others may always sleep with their eyes open. It just depends on the dog.

Is it normal for a dog’s eyes to roll back when they sleep?

Yes, this can happen to dogs when they are asleep and deep in the REM stage. This, too, happens with humans. 

When to worry about my dog sleeping with its eyes open?

While sleeping with open eyes is alarming, it’s normally harmless because it is considered a typical dog behavior. However, there is one exception to this: your dog may be having a seizure.

Don’t panic. This is very rare. This is characterized by a dog’s eyes being wide open — like, bug-eyed. Since most will have slits open or partial eyes open, the difference between partial and bug eyes will be straightforward to see (no pun intended).

How do I know if it’s a seizure?

If you’re now panicking anyway, you can use these questions to help you gauge if it’s a seizure or just sleeping with their eyes open:

  • Do they seem otherwise relaxed?
  • Are they twitching once in a while?
  • Is their breathing normal?

If you answered “yes” to any of these, your dog is okay. If your dog has a seizure, it will be rigid and consistently shaking and trembling like shivering. Their breathing will be labored, and they’ll often have a weird expression on their face. They can often howl or wail, too.

Why do senior dogs sleep with their eyes open?

From a lizard brain point of view, it’s because they have to protect themselves more since they won’t be able to avoid threats quite as easily and will have to be on guard a bit more even as they sleep.

As well, this is the reason why sick dogs will sleep with their eyes open — they know that they have to be extra careful to protect themselves from predators!

Senior dogs are also more likely to struggle with Lagophthalmos since this is a common issue as your dog becomes predisposed to aging eyes and glaucoma.

Why is my dog snoring with their eyes open?

It means that they are having an excellent, deep sleep. Since this is the REM stage, you might even notice that they have their tongue stuck out too! Many dog lovers will call this a tongue blep. 

Why do blind dogs sleep with their eyes open?

This could be for any of the reasons above since dogs don’t know or understand that they are blind. Some experts believe that blind dogs sleep with their eyes open because they don’t understand what eyes are and have no need to close them.

In conclusion

When they are in their deep sleep cycles, dogs can sleep with their eyes open. This is done partially to help it appear to predators as though they are still alert and paying attention — making them less of a target — and it also is just a trait of REM sleep in dogs.

It can be a sign of an illness or seizure in rare cases, so you will need to know what is normal and what isn’t!

When your dog sleeps with their eyes open, they’re enjoying some good downtime so that they can rest and recharge.

Know someone who’s freaked out by these newly discovered details about their dog’s snoozing technique? Share this with them to help them “see” that there’s nothing to worry about!

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Andre Neves

Hi, I'm Andre and I'm the owner of Sula the Border Collie. I love writing about this amazing dog breed here. I joined the Council to be able to reach and educate more people on the joy of having a pet dog.