Have you ever looked at your dog while they were sleeping and suddenly noticed their eyes were partly open? It can be a little unsettling. One minute your pup looks peacefully curled up, and the next, they seem to be staring into space like they are wide awake.
Before you start worrying, take a breath. Dogs can sometimes sleep with their eyes partly open, and in many cases, it is completely normal. You may see a small gap between the eyelids, the eyes rolled slightly upward, or even a pale-looking membrane covering part of the eye.
That strange-looking membrane is often the dog’s third eyelid, also called the nictitating membrane. Dogs also go through different stages of sleep, including REM sleep, when dreaming and little movements can make their eyes look even more unusual.
Still, there is an important difference between a dog that occasionally sleeps with partly open eyes and one whose eyes cannot properly close or look irritated while resting. Redness, discharge, squinting, pain, swelling, or difficulty closing the eyelids are reasons to speak with a veterinarian.
So, why do dogs sleep with their eyes open? Let’s take a closer look at what may be happening behind those sleepy little eyes.
Is It Normal for Dogs to Sleep With Their Eyes Open?
Yes, occasional sleeping with the eyes partly open can be normal for dogs. It may happen during lighter stages of sleep, during REM sleep, or simply because the eyelids do not remain completely closed throughout every moment of rest.
Sometimes what looks like an open eye is not actually the exposed eyeball at all. You may be seeing the dog’s third eyelid moving across the surface of the eye.
This is one of those wonderfully strange things about our four-legged companions that can look much more dramatic than it really is.
If your dog is otherwise comfortable, wakes normally, behaves as usual when awake, and has healthy-looking eyes, an occasional half-open eye during a nap is generally not something to panic about.
Dogs also have plenty of other unusual-looking sleep habits. Their sleeping position, for example, can tell you quite a bit about how comfortable they are. If you have ever wondered what all those curled-up, sprawled-out, or upside-down positions mean, you can learn more about different dog sleeping positions.
Why Do Dogs Sleep With Their Eyes Open?
There is not one single explanation that applies to every dog. Their sleep habits can vary, and several normal things may make their eyes appear open while they are actually fast asleep.
1. Your Dog May Be in a Different Stage of Sleep
Dogs do not sleep in one uninterrupted state from the moment they lie down until they wake up. Their sleep moves through different stages, and their bodies can behave differently during each one.
During lighter sleep, a dog may look almost awake even though they are resting. Their eyelids may not be completely closed, and they may respond quickly if you quietly call their name.
Then there is REM sleep, the stage associated with dreaming. This is when you may notice little paw movements, twitching whiskers, changes in breathing, soft whimpers, or tiny movements of the eyes beneath the eyelids.
So if your pup is sleeping peacefully while their eyes are slightly open and their paws are moving as if they are chasing something wonderful in dreamland, they may simply be having a very active dream.
2. You May Be Seeing the Third Eyelid
This is probably the most fascinating part of the whole mystery.
Dogs have a third eyelid, known scientifically as the nictitating membrane. It sits in the inner corner of the eye and helps protect the eye and spread tears across its surface.
When your dog is sleeping, this membrane can move across part of the eye. Because it can look pale, whitish, pinkish, or slightly translucent depending on the dog, it can easily make you think their actual eye is open.
In other words, you may be looking at your sleeping dog’s third eyelid rather than a fully exposed eyeball.
It is one reason dogs can sometimes look a little spooky while they are completely comfortable and deeply asleep.
3. Your Dog May Simply Have a Habit of Sleeping This Way
Just like people, dogs have their own little sleeping personalities.
One dog may curl into the tiniest ball, another may stretch out across the entire sofa, and another may sleep upside down with their paws in the air. Some dogs occasionally rest with their eyelids slightly open, while others almost always keep them tightly shut.
If your dog’s eyes have looked this way during sleep for a long time and there are no signs of discomfort, it may simply be one of their individual sleeping habits.
The important thing is to look at the whole picture, rather than judging the behavior from the eyes alone.
For example, a dog who sleeps tucked underneath furniture may simply be looking for a quiet, secure place to rest. If that sounds familiar, you can read more about why your dog sleeps under your bed.
4. Facial Anatomy Can Make It More Noticeable
Some dogs are more prone to problems with complete eyelid closure because of the shape and structure of their faces and eyelids.
This can be particularly relevant in some flat-faced breeds, including Pugs, Bulldogs, and Boston Terriers. Their facial anatomy can leave the eye surface more exposed in some individuals, especially if the eyelids do not completely cover the eye during rest.
That does not mean every flat-faced dog that sleeps with partly open eyes has a problem. It simply means that persistent or obvious exposure of the eye deserves a little more attention because the cornea needs protection and lubrication.
And if you have a breed with prominent eyes or unusual eyelid anatomy, it is worth mentioning any persistent eye-opening during sleep to your veterinarian during a routine checkup.
What Is the Third Eyelid in Dogs?
If you have never heard of a dog’s third eyelid before, seeing it for the first time can be quite a surprise.
The nictitating membrane is a thin protective structure found in the inner corner of a dog’s eye. It helps protect the surface of the eye and contributes to keeping it moist and clean.
When your dog is awake and looking around normally, you may barely notice it. During sleep, however, the third eyelid can become much more visible.
This is especially noticeable when the dog’s eyes roll slightly upward during sleep. You might see what looks like a pale film covering part of the eye and wonder whether something is wrong.
Often, that is simply the third eyelid doing its job.
However, a third eyelid that remains prominently visible while your dog is awake, especially if it appears suddenly or is accompanied by other symptoms, should not automatically be assumed to be normal. Eye irritation, illness, injury, or other problems can cause changes around the eye, so a veterinarian can help determine what you are actually seeing.
Why Does My Dog Sleep With One Eye Open?
It can look especially strange when only one eye is partly open.
Sometimes this is simply an individual sleeping habit. The eyelids do not necessarily close in exactly the same way on both sides while a dog is resting, and the third eyelid can also become more noticeable in one eye than the other.
But if your dog has suddenly started sleeping with one eye open, or that eye looks different from the other one, pay closer attention.
Look for redness, discharge, squinting, rubbing, swelling, cloudiness, or signs that your dog does not want you touching the area. A sudden change is more meaningful than an occasional odd-looking nap.
When Should You Worry About Your Dog Sleeping With Their Eyes Open?
This is the part every dog parent really wants to know.
An occasional half-open eye during sleep is one thing. An eye that remains exposed and uncomfortable-looking is another.
It is a good idea to contact your veterinarian if you notice any of the following:
- Redness around the eye
- Unusual discharge, especially thick or persistent discharge
- Squinting or keeping the eye tightly shut
- Frequent blinking
- Rubbing or pawing at the eye
- Swelling around the eyelids
- Cloudiness or a change in the appearance of the eye
- Obvious pain or discomfort
- Difficulty closing the eyelids completely
- A sudden change from your dog’s usual sleeping or eye behavior
- Other unusual signs occurring at the same time, particularly neurological changes
These signs do not automatically mean that something serious is wrong. They simply mean the eye deserves a professional look rather than being written off as a funny sleeping habit.
Changes in sleep can also be more meaningful when your dog is already unwell. For example, dogs may alter their sleeping positions when they are uncomfortable, and dog sleeping positions when they are sick can sometimes provide useful clues about how they are feeling.
What Medical Problems Can Affect Eyelid Closure?
Most dogs that occasionally sleep with their eyes partly open do not have a medical problem. However, there are conditions that can prevent the eyelids from closing properly or cause the eye surface to become exposed.
Lagophthalmos
Lagophthalmos is the inability to completely close the eyelids. When the eye remains partly exposed, the normally protected surface of the eye can become vulnerable to dryness and irritation.
If a dog cannot fully close an eye, especially while sleeping, it is worth having the eye examined rather than assuming the behavior is simply a quirky habit.
Eyelid or Facial Anatomy
Some dogs have eyelid shapes or facial structures that make complete closure more difficult. This is one reason certain breeds may be more susceptible to exposure-related eye problems.
Your veterinarian can examine the eyelids, cornea, and surrounding structures to determine whether the eye is being adequately protected.
Eye Injury or Irritation
An injury, irritation, inflammation, or another eye problem can sometimes change the way a dog holds their eyelids.
If your dog is suddenly squinting, rubbing their eye, avoiding bright light, or keeping one eye partly or completely closed, do not wait for the next sleepy episode to investigate it. Eye problems can worsen quickly, so professional advice is the safest choice.
Neurological Problems
Neurological conditions can sometimes affect the muscles and nerves involved in normal eyelid movement. However, sleeping with partly open eyes by itself is not enough to conclude that your dog has a neurological disorder.
If the eye change occurs together with unusual weakness, abnormal movements, difficulty walking, loss of balance, seizures, or other sudden changes, seek veterinary attention promptly.
Normal or Concerning? A Quick Look
| What You Notice | What It May Mean |
|---|---|
| Eyes slightly open during an occasional nap | Often a normal sleeping habit |
| Eyes partly open with the pale third eyelid visible | May be normal during sleep |
| Eye movements, paw twitching, or little noises during sleep | Can happen during REM sleep and dreaming |
| One eye occasionally appears slightly open | May simply be an individual sleeping habit |
| Redness, discharge, or swelling | Needs veterinary attention |
| Squinting, rubbing, or obvious eye discomfort | Possible eye problem; contact your veterinarian |
| Unable to close the eye properly | Should be assessed by a veterinarian |
| Sudden eye changes with other unusual symptoms | Seek veterinary advice promptly |
Should You Wake Your Dog If Their Eyes Are Open?
Usually, there is no need to wake your dog simply because their eyes are partly open.
If they are breathing normally, resting comfortably, and otherwise behaving like themselves, let your sleepy pup enjoy the nap. Dogs can look surprisingly dramatic while dreaming, and waking them every time an eyelid moves would probably give both of you a rather restless night.
Instead, observe them quietly.
If the eyes close normally when your dog changes position or wakes up, and there are no signs of irritation or pain, that is reassuring. If the eye remains exposed, looks uncomfortable, or your dog cannot close it properly, that is when a veterinary check becomes more important.
And if your dog is resting because they are recovering from an illness, their overall comfort matters too. Simple changes in the way they settle down, where they sleep, and how relaxed they appear can sometimes help you understand what they need. In those situations, knowing how to comfort a sick dog can be helpful alongside following your veterinarian’s advice.
What If My Dog’s Eyes Roll Back While Sleeping?
This can look even scarier than ordinary half-open eyes.
During sleep, particularly during REM sleep, a dog’s eyes can move beneath the eyelids or roll upward so that you see part of the eye or a pale membrane. Their paws may twitch, their whiskers may move, and they may even make tiny sounds while dreaming.
It can certainly make a peaceful dog look as though they have entered another dimension for a few seconds!
If your dog wakes normally and acts completely fine afterward, this kind of sleep movement is often not a reason to panic. However, unusual movements that happen while the dog is awake, prolonged episodes, loss of awareness, collapse, or other concerning neurological signs should be discussed with a veterinarian.
What Should You Do If Your Dog Regularly Sleeps With Their Eyes Open?
Start by observing rather than assuming.
Look at how much of the eye is visible, whether the third eyelid seems to be covering it, and whether your dog can fully close the eyelids when awake and asleep. Notice whether the behavior has always been there or whether it is a recent change.
Most importantly, check your dog’s overall behavior.
Are they eating normally? Playing normally? Comfortable? Responding to you? Are the eyes clear and free from redness or discharge?
Other everyday behaviors can provide useful context, too. A dog who is relaxed, engaged, and behaving normally will often show plenty of other positive signals, from their body language to their willingness to play and interact. These can be helpful when considering the bigger picture of signs of a happy dog.
If everything else looks normal and this is simply one of your dog’s funny little sleeping habits, there may be nothing to worry about. If something feels different or the eye itself looks unhealthy, trust your observation and ask your veterinarian.
Frequently Asked Questions
Dogs may sleep with their eyes partly open during certain stages of sleep, including REM sleep. You may also be seeing their third eyelid, or nictitating membrane, rather than a fully exposed eyeball. In some dogs, it is simply an individual sleeping habit.
It can be. Some dogs occasionally sleep with one eye partly open without any health problem. However, if one eye suddenly starts staying open, looks different from the other eye, or becomes red, swollen, painful, or watery, it is best to have your veterinarian check it.
The third eyelid is a protective membrane located in the inner corner of the eye. It can become more visible while a dog is sleeping, particularly when the eyes move or roll upward. Seeing a little of it during sleep can be completely normal.
Dogs can show partly open eyes and other small movements during REM sleep, the stage associated with dreaming. You may also notice paw twitching, whisker movements, little noises, or changes in breathing. These behaviors can be normal parts of sleep.
Occasional partial opening during sleep is often harmless. The concern is when the eye remains exposed because the eyelids cannot close properly. Persistent exposure can allow the surface of the eye to become dry or irritated, so difficulty closing the eye should be assessed by a veterinarian.
There is no single amount of time that is considered normal for every dog. An occasional partially open eye during a nap is different from an eye that remains exposed regularly or cannot close properly. Pay attention to the appearance of the eye and any accompanying symptoms rather than focusing only on the clock.
Usually, there is no need to panic if your dog occasionally sleeps with their eyes partly open and otherwise appears healthy and comfortable. Redness, discharge, squinting, rubbing, swelling, pain, cloudiness, or difficulty closing the eye are more concerning signs and warrant veterinary advice.
Final Thoughts
Dogs have a wonderful talent for making even the most ordinary things look a little mysterious.
Sleeping with their eyes partly open is one of those moments that can make you stop, stare, and wonder what on earth is going on with your furry friend. In many cases, your dog is simply sleeping, dreaming, or showing a little of that clever third eyelid that helps protect their eyes.
So, if your pup occasionally gives you that half-awake, slightly spooky stare while peacefully snoring away, you probably do not need to disturb their beauty sleep.
Just keep an eye on the eye itself.
If it becomes red, painful, swollen, cloudy, produces unusual discharge, or your dog cannot properly close it, that is when a veterinarian should take a closer look. A funny sleeping habit is one thing; an uncomfortable eye is another.
After all, knowing your dog’s normal little quirks makes it much easier to notice when something genuinely changes.
