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Why Is My Dog's Third Eyelid Showing? (4 Common Causes)

Adrienne is a certified dog trainer and former veterinarian assistant who partners with some of the best veterinarians worldwide.

Did you know how many eyelids dogs have?

Did you know how many eyelids dogs have?

What Is That Membrane in My Dog's Eye?

Also known as the nictitating membrane or haw, the dog's third eyelid is something most owners aren't aware of until they see it for the first time. All dogs have this membrane found in the inner corner of the eye, but it is typically noticed only when it is drawn horizontally across part of the eye. Its color varies depending on the dog's breed and can range from clear to cloudy.

What Does a Dog's Third Eyelid Do?

Deborah S. Friedman, D.V.M. and diplomate with the American College of Veterinary Ophthalmologists has several explanations.

  • The third eyelid acts as the dog's "windshield-wiper" for the cornea, effectively removing debris or mucus from it.
  • This membrane is responsible for producing about one-third of the dog's tears, since it has one of the most important tear glands attached at its base, and its lymphoid tissue acts as a lymph node, producing antibodies to fight off infections.
  • It also helps prevent injuries to the dog's cornea.

In dogs and cats, this membrane is not normally visible other than when the animal is sleeping or suddenly awakens from sleep. Indeed, if you lift the eyelid of a sleeping dog, you'll likely see the whole eye covered by the third eyelid.

The dog in my pictures awakened suddenly after resting on my legs, and once she was fully awake, her third eyelid re-positioned normally.

However, the prolonged presence of the third eyelid, even when the dog is bright and alert, often denotes some sort of medical problem.

Did You Know?

According to Animal Eye Care LLC, dogs have two tear glands in each eye, whereas humans have only one. The orbital tear gland is responsible for producing 60 percent of tears and the third eyelid tear gland produces 40 percent.

Reasons Why the Eye Membrane Might Be Showing

If your dog's third eyelid made a sudden appearance and hasn't gone away, you may be wondering what's going on. The third eyelid should not be seen after the dog has awakened and is bright and alert. There are several possibilities for prolonged membrane exposure that range from ocular problems to more systemic autoimmune or neurological disorders.

Here are a few of the most common causes for the prolonged appearance of a dog's third eyelid:

  1. Eye Problems
  2. Cherry Eye
  3. Neurological Disorder
  4. Poor Physical Health

Continue scrolling to learn about some common and not-so-common medical issues associated with the abnormal appearance of the dog's third eyelid.

Squinting along with the appearance of the third eyelid can be a sign of pain and some ocular issue.

Squinting along with the appearance of the third eyelid can be a sign of pain and some ocular issue.

1. Canine Eye Problems

  • The presence of the third eyelid could be a sign that the dog's eyeball has sunken into its socket, often because of pain and inflammation. The third eyelid covers the eye to protect it from further injury, as in the case of corneal trauma.
  • It could also be that the structure meant to hold the third eyelid in place either weakened or got injured.
  • A further possibility may include allergic conjunctivitis.

2. Cherry Eye

Some dog breeds are prone to prolapse of a gland found in the dog's third eyelid—a condition known as "cherry eye" mostly because of its bright-red presence resembling a cherry in the corner of the dog's eye.

This is a congenital disorder found commonly in certain dog breeds such as cocker spaniels, beagles, Boston terriers, and bulldogs.

What happens is the cartilage responsible for supporting the membrane folds over, causing the third eyelid to no longer work well as a "windshield wiper." This results in a gland that is exposed and potentially inflamed.

3. Neurological Disorders

Some neurological diseases may cause loss of function to the nerve that supplies the third eyelid.

Horner's syndrome is a common neurological disorder that occurs suddenly and is characterized by sunken eyes, droopy eyelids, droopy facial features, small pupil size, and the prolapse of the third eyelid.

Dilated blood vessels in the affected area cause owners to sometimes report that it feels warmer to the touch. The cause is unknown, but at times it can be triggered by trauma to the head, bite wounds, a herniated disc, a growth pressing on a nerve, a side effect of some medication, or a middle or inner ear disease.

While any dog can develop Horner's, golden retrievers and cocker spaniels are slightly predisposed. Other neurological disorders that can cause a third eyelid to be exposed include tetanus and dysautonomia.

4. Poor Physical Health

Certain physical conditions that are known for relaxing the muscles found around the eyeball and for causing the settling of the eye deeper into its socket may be a cause for the appearance of the third eyelid.

Dogs who are malnourished, dehydrated, have lost weight or are generally not feeling well may manifest protrusion of the third eyelid.

Treatment varies depending on the cause. In some cases, a cause is never found. These are referred to as "idiopathic."

Sometimes the issue resolves on its own after several weeks. However, if it turns out to be an eye issue, as with all eye problems, it's best to see a vet, or better, a board-certified veterinary ophthalmologist immediately to prevent potential vision loss.

Questions to Ask the Vet

If you visit the vet or are trying to get a better idea of what's going on, here are some questions that can help you determine what's going on with your pet:

  • Did your dog bump its head? Or experience any other trauma? You might just need a cold compress on the eye for anywhere from a few to 30 minutes.
  • Is the eye okay aside from the third eyelid showing? In that case, and if both eyes don't also react similarly to light, there might be a cranial lesion.
  • Is your dog struggling to keep that eye open? This might indicate an eye injury.
  • Is there any discharge? This could be a sign of an eye infection.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

Question: I understood that 'shark eye' is a sign of stress. Is this the same as the third lid showing itself?

Answer: 'Whale eye' or 'moon eye,' (I never really heard the term shark eye before) is the term used to depict dogs who are showing the white part of the eye, and yes, you are correct in that it can be seen in situations of stress or aggression.

A classic example is a dog who is guarding a bone. The dog has his head lowered over the bone but he may be looking slightly sideways to make sure nobody comes near, and the whites of the eyes may be showing.

The third eyelid showing is a different situation. This involves a different part of the eye which is the third eyelid which resides in the inner corner of the eye when the dog is alert and awake, but slides over the eye when the dog falls asleep or when the dog is feeling unwell or there is some neurological dysfunction.

Question: I've noticed my dog's “third eyelid” is white and the other is more of a brownish? Should I be concerned?

Answer: The third eyelid's color can vary based on the pigment of the surrounding skin. A dog's third eyelid can therefore be light pink, white or it may have a dark rim color to it. One dog can one on one side is pink or white and the other side with a dark rim at the top. Of course, best to mention it to the vet next time, just to play it safe.

Here is a picture of a third eyelid with a dark colored rim:

And here is one that is white in color:

Question: My dog had his teeth removed this week and he suddenly has this third eyelid, should I take him to the vet? He is also shaking.

Answer: You might want to call your vet to let him know your dog's third eyelid is showing after surgery. Sometimes the stress of a procedure - causes stress that allows other things to crop up. If he is shaking, he may have pain. Has your vet prescribed any pain meds? Hopefully, this is something that will resolve spontaneously.

Question: I was once told that my dog was over-exercised and exhausted because when she slept her 3rd eyelid was visible. Is this the case? We have reduced her walk time, but she still sleeps deeply with 3rd eyelid visible.

Answer: I have never heard about that! It's sure an interesting theory, but I think it lacks validity. I can attest that I had lazy dogs and their third eyelid was always showing when they slept. It's just a natural, protective mechanism.

© 2014 Adrienne Farricelli


Adrienne Farricelli (author) on September 03, 2020:

Dana, only a veterinarian can accurately diagnose your dog. Due to the fact your dog is older, there can be a variety of underlying issues going on. Please see you vet to play it safe. A dog with kidney failure would most likely show also other signs such as vomiting, increased drinking and urination, weight loss etc.

Dana S on September 02, 2020:

my dogs third eyelid is showing but it goes from one eye and then next day it will be fine but the other eye will have it. She's really old. Could this be a sign of kidney failure? Someone ment3that to me.

Mahmoodayaz on July 19, 2020:


I have a question.

I have an American Akita male. When it was born, it had third eyelid showing.

What can be the casue of this? What can be the treatment?

Tiffany on July 09, 2020:

On this day last year my dog's third eye appeared over the weekend and he was lathargic. I was out of town at the time so my neighbor who was watching him took him to the emergency vet. They put him on IV's for two days and he seemed to be better. The next day his third eye appeared again. I took him to my primary vet and they didn't see anything wrong other than when they turned his neck he yelped. They gave me medication for him to take. The next day he was dead! I was devestated! He suffered all night because the blanket was soaked with his saliva and he died with the blanket tightly clentched in his mouth. A year later I'm still upset because I thought the vet could have done more. I'm guessing some neurological issues were happening. Still sad about it. I will be one year tomorrow since he's passed.

Adrienne Farricelli (author) on June 29, 2020:

Eliette, It can be that there is a corneal scratch and this is usually quite painful and the body may respond to the inflammation by releasing the third eyelid. I would suggest seeing the vet as soon as possible. He or she can stain the eye and look for scratches and if there are, your dog may need antibiotics.

Adrienne Farricelli (author) on June 29, 2020:

Hi Fer, please give the vet that did the surgery a call and report everything you are noticing and the itching and appearance of third eyelid. He/she will be the best person to advice and know what may be going on.

Fer on June 28, 2020:

My dog had an eyelid mass growth and it changed its color and shape (got much larger) so it started bothering him. He was scratching a lot and after a few weeks the third eyelid started showing.

He got the mass growth removed but the third eyelid is still showing. He still tried to scratch his eye even though the post-surgery seems to be going well. Why does it itch it so much still, why is the third eyelid still showing and how does it go back to normal? Thank you!

Elliette Smith-Nancarrow on June 28, 2020:


My dogs third eyelid is showing in his right eye, it’s covering it in the corner and making him look like his eye is turning. He is squinting a bit but only when he is looking at one thing for a period of time, he can open his eye filling and the eyelid goes away, he doesn’t seem to be in any pain, and the eye is not watering. He’s eating, drinking and playing like he normally would and definitely is not lacking energy. I’m wondering if this could maybe be from playing with the cats and they could of accidentally scratched his eyeball?

Adrienne Farricelli (author) on June 15, 2020:

Hi Lesley, sometimes this can be due to some local irritation such as a hair growing oddly and bothering the eye, a growth on the eyelid, a blade or seed of grass stuck in the eye. However is it one eye or both? This would be important to know. Please see your vet for diagnosis and treatment.

Adrienne Farricelli (author) on June 15, 2020:

I would be wary of this pup especially the very little energy and squinting. I don't think this is normal at all. Please get your puppy from a reputable breeder who offers health guarantees on the pups so to avoid heartaches.

Adrienne Farricelli (author) on June 15, 2020:

Hi maryem, sometimes it is not easy finding the underlying cause for the third eyelid to show. I don't think there is much you can do until you see the vet. Maybe you can ask a vet online and post pictures for some insights until you can see the vet.

Adrienne Farricelli (author) on June 15, 2020:

Hi K, Although rare, this may be a tear gland tumor, which is more likely to occur in older dogs. It may be helpful seeing a veterinary ophthalmologist to see what may be going on exactly.

K on June 09, 2020:

According to our vet, my dogs third eyelid is showing and should be fine to leave as long as there’s no discomfort- however, when my dog chews,yawns or does any strenuous activity \movements, a cyst-like mass bulges out of the inner corner of that eye. Her eye is tearing more than usual, as she has the little tear marks on her fur on that one side (which she didn’t have before) my vet said this could be a cherry eye, but it doesn’t look fleshy, it looks more liquid filled (like a cyst) what can it be if not cherry eye?

maryem on June 07, 2020:

hi, my dog, tokyo, is almost one , seemed fine yesterday and suddenly i noticed that his third eyelid was showing in both eyes ,i thought it's because he hasn't slept much and when i put him in his bed he immediateky feel asleep. but this morning his third eyelid is still showing and it's red , and i have read some comeents something about the ears and i think my dog's ear changed apperance .... what should i do ??? i can't get him to the vet right now

briannakosma on June 04, 2020:


I am really in need of some advice. I am in the process of getting a puppy. I visit the puppy weekly and will be picking her up as of 2 weeks from today.

During my last visit I noticed some things that sort of alarmed me. She was squinting a lot, when she rolled on her back her eyes went back in her head. Her eyes have a blueish tint and her third eye is visible. She also had some red in the corner of her eyes.She also had very little energy (her brothers and sisters also were sleeping, they had just eaten). I have never had a puppy and have always adopted. I even reflected to my fiance that shes looking around like she needs glasses, then began researching later about this.

Are these things to worry about or is that typical for puppies?

Lesley Richings on June 01, 2020:

Hi, my dog is 15 this year and has been in good health through out his life. 3 days ago we noticed he had Third Eye. He doesn't appear to be in any discomfort with is but does squint when out in the sunshine. He is still as active as he was for a 15 year old and he is eating and drinking as normal. No other obvious signs pain or in his general demeanor

Any advice you could offer would be very much appreciated

My dog is a small terrier

Kind Regards

Lesley (anxious mummy)

Tiffany Zheng on May 28, 2020:


My dog was eating dinner and all of a sudden his eyes started too look at different directions and his third layer was showing. Recently there has been lots of thunder which scares him and also causes him to bump his head on tables from being scared. But he has experienced ear infections.

I often see my dog having a red eye but I’m not sure if it’s allergies or not.

He is a golden retriever.

Ayla fencl on May 21, 2020:

My dog has ita third eyelid showing when she looks fown but when she looks up its normal again is the heath for the dog. I am only 13 and i have 4 dogs that dont have this problem. What should i do.

Stinky16 on April 04, 2020:

My Alaskan Husky/German Shepard hikes and snow skis with me. She is 3 years old and has been very active in these activities her entire life. On our last few snow skis, Which have been 4 to 6 hours of strenuous Hiking and running down hill; and the weather has been full spring sun. I've notice her third eyelid has been showing. It has been two days since our last hike and her eyelids are still showing but not as much. There is also a little clear discharge from each eye.

Are her eyes being damaged or is this normal?

Adrienne Farricelli (author) on February 13, 2020:

If the corneal ulcer occurred secondary to the lacking blink reflex, and your dog also has a floppy right ear and the right side of the mouth loose, this sounds more neurological. It can well be Idiopathic facial paralysis which is similar to "Bell's palsy" in humans, but there may be other causes to rule out (inner ear infection, trigeminal nerve issue etc). I think a neurological evaluation is appropriate considering the symptoms you are seeing, but seeing an ophthalmologist may still be important if the ulcer is not healing and to prevent further damage to the eye considering the lack of blinking (eye drops to be put often throughout the day). The lack of blinking is often the most concerning feature in these dogs. I hope your dog gets better soon.

klnelson524 on February 13, 2020:

The vet has been treating my dog, maltipoo who is 6 with a corneal ulcer, with Tobramycin and Optixcare lube. The corneal ulcer lasted 2 weeks in counting (getting better but still there) and appears to be a symptom of another underlying cause.

My dog’s additional symptoms:

1. Right eye can’t blink (no menace, response)

2. Third eyelid showing

3. Right ear is floppy

4. Right-side of mouth is loose

She is still eating, drinking, playful (for now). Vet wants us to see an ophthalmologist, but would they be able to determine why she is not blinking? I think we should see a neurologist since it appears something neurological is happening, but is that premature or am I right in being worried? I know all of this could be idiopathic but don’t want to assume that and something more serious is going on. Any advice you can give would be great!

Adrienne Farricelli (author) on November 25, 2019:

Maritza, you may want to get a second opinion or perhaps even better, get a referral to a board-certified veterinary ophthalmologist.

Maritza on November 15, 2019:

Hi ! My basset has about two weeks with the third eye lid showing. We went to the vet and he said he didn’t see any cornea injury and prescribed a steroid cream. I actually feel the steroid cream causes it to get worst. In addition their are days where his eye is totally fine. Also some days both eyes look

Adrienne Farricelli (author) on September 03, 2019:

Allergies may be a possible cause for the third eyelid in a dog to show, but there can be several others causes too. Play it safe and have your dog see the vet.

Toni Burrell on August 28, 2019:

My 8 month blue nose pit bull woke up today and her thirdeye lid was showing I haven't changed anything except I went to my son's house and stayed 3 days and he has cats could she be allergic

Adrienne Farricelli (author) on August 27, 2019:

Dana, I wished I could help you, but due to the fact that your dog is showing these concerning signs, on top of the third eyelid showing, ideally you should see a vet sooner than later.

Adrienne Farricelli (author) on August 13, 2019:

Chris, your vet is the best person to trust on this. It is true that some dogs may have eye anatomy that can make them more prone to eye problems. Have you mentioned this to the breeder?

Julia on August 12, 2019:

Dylan, 8 year old greyhound, is lethargic and when resting - which is always, his maw is evident. Which should require a call to the vet, maw or lethargic or are they connected?

Chris on August 10, 2019:

A few months back, Winnie, my 18 month old goldendoodle started getting routine eye infections. We live in the city, where she's routinely dunking her head in the communal dog bucket, and sharing space with different dogs everyday at the local dog park. Her getting an eye infection wasn't all too surprising considering how often she's at the park, and how many neglectful pet owners there seem to be in the city. I've taken her to the vet twice to be examined and she was prescribed different eyedrops each visit. The second bottle seemed to work better and she hasn't had an eye infection in a few months.

Between vet visits I noticed that Winnies 3rd eylids were always showing, pretty much extending to her iris on the inner corner of her eye. They don't appear to be inflamed, and its definitely not cherry eye- my other dog has had surgery for both eyes, so it's definitley something I'm familiar with. I made sure to point it out to the vet, and I was told its just her eyes anatomy as there was no inflammation or cause for concern.

It made sense to me and overall I trust my vet, I just figured it couldn't hurt to get a second opinion. Any feedback you have would be greatly appreciated. Thanks!!

Dana on August 08, 2019:

Hey, my female dog, she is a mix of golden retriever, labrador, and collie. She is 5yrs and today her third eye appeared covering half of both of her eyes. Light bothers her and so she closes them and then rarely opens them again. She seems kinda discouraged and not with much energy. She also has a lot of left over tears, is his bad? Will it return to normal? What happens if I take her to the vet after 2 days?

Adrienne Farricelli (author) on July 28, 2019:

Tina, this is something you need to have checked out by your vet as this sounds concerning.

Tina Dempsey on July 25, 2019:

My dogs third eyelid is covering half his eye. He was in a fight with our other dog three weeks ago. How can I help him. It just showed up yesterday. His eye is watering but other than that doesn't look infected. I noticed when I threw him a dog bone and he acted like he didn't see it. He usually catches the bone. He's a golden retriever

JulieEM on June 27, 2019:

Hi, my dog recently started showing signs of lethargy and his third eyelids close about a quarter of the way across both eyes with a reddish, color. I took him to the vet and both his blood and vitals came back normal. But he's not normal, I can tell he's in some sort of pain I just can't tell where. He will take down peanut butter and sometimes food, but when I give him a treat (that he usually loves) he'll drop it and squeal a little bit. I'm thinking maybe it's an ear or mouth infection?

Adrienne Farricelli (author) on June 02, 2019:

This is concerning. Eye problems in dogs should be seen as soon as possible especially if the dog is keeping on eye closed. If the other eye has the third eyelid showing it may be something systemic going on.

Adrienne Farricelli (author) on June 02, 2019:

Considering that aging may lead to a en extensive list of problems, your theory may be correct. Keep us posted on what your vet finds.

Deb on June 01, 2019:

My Lab has one eye shut and I can tell it hurts to the touch and the other I believe it’s his third eyelid that shows. What do I need to do?

Nicole Hoida on May 27, 2019:

My 14 year old pit bull’s third eyelid just started showing continually... She’s not wincing if I put a little pressure, there’s no leakage, and it doesn’t seem to be affecting her. But still think I should take her in. Is this an age thing?

Ariel Dllis on March 16, 2019:

Can your dog die??

Sarah on October 28, 2018:

A friend's pup's third eye, just on the right side, seems to pop up but only when he is chewing on a toy or bone, then it goes away. Is this a cause for concern or a vet visit?

Adrienne Farricelli (author) on August 23, 2018:

Chris, I would think ruling out a tumor in the sinus and/or nasal cavity is important at this age. However, a sinus infection as a result from cleaning out the abscess can also be a possibility. A dental or skull xrays to check her sinuses and the area around the teeth may be insightful before proceeding with more expensive/invasive tests. On occasion, some extraction sites take a while to properly close and an opening from the mouth to the sinuses may play a role in causing the symptoms you are seeing. I hope this gets sorted out for you and your dog.

Chris Stiles on August 06, 2018:


My Shepard/boxer mix & she is 10yrs old just recently had her back left tooth extracted she was fine until the antibiotics had run out now her third eye lids are showing in both eyes & there is a white discharge coming from her eyes she also has green discharge coming from her nose & her energy levels dropped big time. we took her to the vet & they said that it's possible that she may have polyps or a tumor in her nose & the best way to know is if they do a scope or MRI I'm really worried about her but I am wondering if its possible that from the tooth it went abscess & the infection spread before they got to the tooth or if it's because of allergies the reason I ask is because she was fine on the antibiotics & now that she is off of them she seems like she's in a lot of pain. please help me & my wife out we love our dog like she is our daughter & it hurts to see her in pain.

Adrienne Farricelli (author) on July 27, 2018:

Hello Clauda, I hope the specialist gets your beagle's eye condition sorted out. At the vet hospital I used to work for, we used to have a very experienced eye specialist come once a week. People were traveling from far to see him. I remember he used to check eye pressure using a procedure called tonometry. Often, this helped confirm or rule out glaucoma. It's importatnt finding the underlying cause for the increased pressure in the eye. Best wishes for your boy.

Claudia Porter on July 10, 2018:

Hi - We are currently experiencing this with our beagle. It's heartbreaking because we have been tot the vet 3 times so far. His one eye has high pressure levels and we have some drops but they don't seem to be working. We are going to a specialist later this week. He doesn't seem to be in pain, but his eyes look terrible. Thanks for this article. It gives me an idea of what might be going on.

Amy sardella on June 23, 2018:

My boxer/pit mix has had this corner ( eye lid?) happen before. It just came out and about an hour or so later fixed itself, usually after a nap. This time however he had it last night ,went to bed ,woke up fine. He's been awake for about 30 min.,and now it's back. I don't know what I should do. Can you help me...please... Thank you... Amy S.

Judy Flournoy on April 29, 2018:

9 y.o mini daschund has 3rd eye on both eyes, can't hardly open eyes. what do I do for her?

Adrienne Farricelli (author) on December 31, 2017:

Kaedan you may want to see the vet so to investigate the underlying cause.

Kaedan on December 28, 2017:

My mini dauchshund’s third eyelid is appearing on her left eye. It is morning when I posted this and we both woke up but what do I do if it stays there?

Adrienne Farricelli (author) on November 27, 2017:

Ken, a third eyelid showing is not a sign of old age, I would have her checked out.

Ken on November 18, 2017:

My beagles third eye lid is almost half way covering her left eye, despite her being fully awake and alert .She is of old age so I'm wondering if something is wrong and should take her to the vet or is it just her old age?

Deanna on June 15, 2017:

The third eyelid being seen is common in Saint Bernards and Blood Hounds. My 7.5 month old puppy has always had his showing and looks to be part Blood Hound. Should this be concern?

Adrienne Farricelli (author) on April 29, 2017:

Is she spayed or intact? It could be something is going on medically, see your vet to be sure and mention the odd behaviors you are seeing, It could be an early sign of canine cognitive dysfunction or some sort of pain.

Gwen on April 21, 2017:

My 11 year old Jack Russell is extremely restless , moving from one place to another every 2-3 minutes and she will just stand and stare at me like trying to tell me something ..... What is wrong with her ? She is also acting as though she is nesting ,trying to create a bed in strange areas or within things way too small

Adrienne Farricelli (author) on March 07, 2017:

Hello, I would report to your vet that there has been no improvement and perhaps consult with a specialist if the issue remains unresolved.

Bloodhound mama on February 28, 2017:

My hounds third eyelid became exposed 3 days ago. Took him to the vet the day it happened and ran tests. No damage to his eye. Started him on drops and anti inflammitories. 3 days and no improvement. He is 8 years old, so maybe it may take longer, but I am beyond sick with worry. This is my boy. Any words of wisdom???

PhoolR on February 09, 2017:

My golden retriever is pregnant (day 54) and this has just started happening to her as of last night. Could it be to do with the pregnancy?

Phil on February 09, 2017:

My golden retriever is pregnant (day 54) and this has just started happening to her as of last night. Could it be to do with the pregnancy?

Dolly on December 08, 2016:

My I'll dog woke up one morning with his Horner's Syndrome. He has lymphoma and I do not know how long he has to live. My animals average 22 years. I baby them. The morning I noticed his eye, every 1 to 2 hours I used human Blink drops (an eye moisturizer (over the counter) that I use because I have dry eyes) and by the next day IT WAS GONE. Everything I read given his poor health said it would not go away. I recommend trying this to everyone. Will not hurt your animal. Natural saline.

Adrienne Farricelli (author) on April 07, 2016:

The surgery could be a culprit if your dog is not feeling too well or is dehydrated. Whether it clears up or not depends on the underlying cause. I would mention it to the vet that did the surgery.

Adrienne Farricelli (author) on April 07, 2016:

It's difficult to say if it's painful as it depends on the underlying cause. Age may be a culprit indirectly, meaning that older dogs are more prone to having certain medical conditions that may cause it, best to see the vet.

Sam on April 07, 2016:

My dog has just had a lump removed from his mouth and had an inner ear infection looked at too, ever since the op his third eyelids are visible

Would the op have caused this? He didn't have it before hand and will it clear up?

Thank you

Danise on March 31, 2016:

My dog is 10 years old and her third eye is showing in both eyes. Could age be a reason for this. Is this painful?

Adrienne Farricelli (author) on August 08, 2014:

According to the link below "DLE can also cause inflammation of the third eyelid." In this case, the underlying issue needs to be addressed.

Oneita on August 05, 2014:

Our sheltie was recently diagnosed with Discoid Lupus. Does this cause the appearance of the 3rd eyelid & if so should it be treated?

Adrienne Farricelli (author) on May 19, 2014:

I would get this checked out by the vet just to make sure.

lisa on May 18, 2014:

I got a puppy who was 10 weeks old. .. her third eyelid in both eyes has always been showing ... she's not in pain no discharge no smell no redness... any ideas??

Mona Sabalones Gonzalez from Philippines on February 21, 2014:

Yes, it was cherry eye. She recovered well, but she hates having her photo taken. Maybe it's because of the flash on her eye.

Adrienne Farricelli (author) on February 20, 2014:

Did she have cherry eye? I hope she is doing well after surgery, thanks for stopping by!

Mona Sabalones Gonzalez from Philippines on February 20, 2014:

My dog Ashley Pumpernickel had that. I never knew what caused it but this article helped me understand the third eyelid better. Eventually she needed an operation to have it removed.

Francesca27 from Hub Page on January 08, 2014:

I was wondering why our Akita had that! He has been gone for years. Thanks for the info.

ShyeAnne from Qualicum Bay, British Columbia, Canada on January 08, 2014:

Cool little piece of trivia I did not know. Voted up and Interesting!