Have you ever walked in on your dog looking a little peculiar while sleeping? Maybe you’ve you’ve seen your dog’s eyes remain curiously open while they’re snoozing. Some dog owners may find it thoroughly amusing, while others may get understandably worried at the unusual sight. In this article, we’ll talk more about the phenomenon so you’ll understand more. If you’re wondering ‘can dogs sleep with their eyes open?’, ‘is it something I should be worried about?’ then read on!
Can Dogs Actually Sleep With Their Eyes Open?
Most Of The Time? Not Really!
As cool as it may seem, your dog’s eyes aren’t really open while they’re asleep, even though it genuinely appears like they are. Much like our own eyes, your dog’s eyes will dry out if it’s kept open for longer than usual. Dry corneas can then result in a condition called exposure keratitis. Usually, the only time dogs actually sleep with their eyes open is during surgery when they’re under the influence of anesthesia. In these cases though, the vet may use drops to keep your pet’s eyes moisturized to avoid any complications.
Dogs Have A Third Eyelid
So if your dog’s eyes aren’t open while asleep, then why do they appear as if they are? Well, the truth is that you’re seeing your dog’s third eyelid. That’s the light pink/red tissue that is covering your dog’s eyes to keep the moisturized even when it’s asleep and not blinking.
Photo (including the nictitating membrane) by Doggitydogs via Wikimedia Commons.
It is called the nictitating membrane and it helps protect your dog’s eyeballs. A gland located by it, the nictitans gland, is responsible for 40-50% of your dog’s tears. This membrane basically functions similarly to the regular eyelids, as it also keeps debris from sticking to your dog’s eyes. It also acts as some sort of wiper blade to sweep foreign material from your dog’s eyes, as they can’t very well rub their eyes the same way you and I do when there’s something in ours.
Cats also have a third eyelid, but your dog’s differs from your cat’s because of one thing: the membrane that makes up their third eyelid is completely passive. This means that the retraction of your dog’s eyeball into the orbit is the only thing that triggers the third eyelid to slide across your dog’s ocular surface.
Asleep or not, some breeds’ third eyelid are more visible than others. The relationship between the globe and the orbit will determine its visibility. Dogs with long heads and small eyes will have more prominent third eyelids than those with shorter heads. Nevertheless, the third eyelid should retract and be in its normal position at the inner corner of a dog’s eyes when they’re fully awake.
When Is It Unhealthy? When Should I Be Alarmed?
If your dog’s third eyelid is showing even while they’re awake, it can be indicative of an injury, illness, or a damaged nerve.
There’s a disease, called the “Cherry eye”, and it happens when the supporting cartilage of your dog’s eyelids falls over and thus, loses the ability to function as a protection from contaminants. The gland will be exposed to dirt and can, therefore, result in an infection. This is a painful experience and you will need to bring your dog to a vet immediately.
Prolapsed gland of the third eyelid (cherry eye) in a dog. Photo by Joel Mills
Lagophthalmos is what you call the incapability to close the eyelids completely. It’s actually a common disease found in most dog and cat breeds, particularly in short faced ones like Shih Tzus, Pekingese, Pugs and more. This is characterized by a small opening between your dog’s eyelids when they’re asleep. Because of the importance of the third eyelid, any issues with its health can cause severe damage to your dog’s eyes. Ask your vet about the appropriate treatment if it’s found that they have this condition.
Another Consideration: Seizures or Twitching?
If your dog’s open eyes while snoozing are accompanied by jerky movements, then you have to determine whether your dog is having a seizure or if he’s just twitching due to dreaming. The best way to differentiate is to know that seizures are accompanied by open eyes and a blank stare while dreaming dogs will have partially closed eyes and look relaxed.
The twitching caused by the REM stage of your dog’s sleep will pass when you wake him up (though it’s not recommended that you wake your dog). On the contrary, dogs that are having a seizure cannot be ‘woken’ up from it and you’ll just have to let it pass. It’s not going to be an easy experience, as dogs that are seizing may become vocal with a whine, a moan, a scream, or a howl. Take note that this is involuntary and your dog is not really verbalizing distress. It’s harrowing, but try to keep that in mind.
Involuntary movements are also common with seizures, unlike with twitching that lasts shorter. You might even observe some physiological changes like foaming at the mouth, loss of control over their digestive system, or laborious breathing. Biting their tongue is also a possibility. The best thing you could do at this moment is to move objects away from your seizing dog that they might accidentally smash into.
The aftermaths of these two probabilities are also drastically different. As mentioned before, waking your dog up from a REM state will bring things back to normal (unless your dog snaps at you for waking them up, which is a possibility). However, post-seizure, a dog can be disoriented and dazed. Your dog may not be able to walk properly the first few moments after the attack. It will be hard to watch, but you should remember to treat your dog as gently as possible.
Twitching is really normal for sleeping dogs and should not be a cause of worry. Seizures, on the other hand, can be caused by genetic factors and more. If it’s a recurring problem, consult your vet on why your dog gets attacks and find out how to prevent this from happening. Even if it does happen again, remember to be calm.
In most cases, it’s actually not true that your dog is sleeping with its eyes open. You’re probably just seeing its third eyelid (whose existence you were probably unaware of). If your dog is suffering from Cherry Eye or Lagophthalmos, then you should seek the advice of your vet for further treatment. Pay attention to whether your dog is having a seizure concurrently as that is also something you might want to let your vet know.