8 Reasons Why Your Cat’s Third Eyelid Is Showing

cat third eyelid showig but no symptoms

When you notice your cat’s third eyelid protruding more than usual, it can be a cause for concern.

The third eyelid or nictitating membrane is a protective feature in cats but it should typically not be visible. If you see it frequently, it might be an indicator of underlying health issues.

Here are nine reasons why your cat’s third eyelid might be showing and what these symptoms could mean.

1. Deep Sleep

The one very obvious time you can notice your cat’s inner eyelids is during deep sleep.

Your cat has sleep phases that are very similar to that in humans. There’s a slow wave sleep phase and rapid eye movement (REM) phase.

The sleep wave sleep phase happens when the cat has settled down and started to snooze. It is usually called a cat nap when your cat is asleep but still aware of its surroundings.

After about 15 minutes or so, your cat will start to enter deep sleep or rapid eye movement.

This phase is important to help your cat’s body recover and repair itself.

This sleep phase is also called rapid eye movement because your cat’s eyes are bouncing all over the place.

Your cat can sleep with its eyes partially open with its third eyelids almost fully exposed during deep sleep.

There’s nothing for you to be concerned about as it is a normal occurrence for both cats and dogs.

You can also notice your cat’s third eyelids when it has just woken up from its sleep.

2. Vaccination

If your cat has just gotten its vaccination shots from the local vet, its third eyelid can start to show once it’s back home.

These vaccinations help to protect your cat against many horrible diseases which can be life-threatening and even fatal for young cats.

There are a few common side effects after your cat has been vaccinated.

  • Fever
  • Vomiting
  • Diarrhea
  • Lethargy

Some cats will be affected while some won’t. It largely depends on how sensitive the cat’s body is to the vaccine.

Even if your cat doesn’t show any symptoms, its body is still reacting to the vaccine which mimics the virus and stimulates the body to produce antibodies to protect the cat.

On a biological level, the body thinks that the cat is in ill health which causes the cat’s nictitating membrane to show.

3. Recovering From Sedation

When your cat undergoes a procedure, an anesthetic is used to make the cat unconscious and block any feelings of pain.

Even after the cat has woken up, it will still be feeling very drowsy and sleepy which is a common side effect post sedation.

It is common to see your cat’s third eyelid showing with its eye dilated when it is in this sleepy and drowsy state due to being anesthetized.

4. Haws Syndrome

Haws syndrome is used to describe the exposure of both third eyelids showing in a cat.

There isn’t one definite cause for Haws syndrome but scientists believe that the cat’s gut condition is usually the culprit.

Cats with Haws syndrome are known to also have diarrhea and other stomach problems like flatulence, bloating or blood in the stools.

Other symptoms will also include loss of appetite and lethargy.

Your cat’s stomach issue could be caused by something as simple as your cat eating spoiled food which resulted in food poisoning.

Or it could be something more serious like intestinal obstruction or parasites.

Intestinal parasites are common in most cats, especially young cats or cats that have never been dewormed before.

These parasites will live and reproduce in your cat’s gastrointestinal tract.

5. Cherry Eye

Some pet owners think that having a cherry eye is the same as their pet having a sore eye. But it is a different medical condition altogether.

Beneath your cat’s third eyelid lies the nictitans gland which is a small pink tissue that produces tears.

The presence of tears doesn’t mean that your cat is capable of crying. The tears are used to clean off any dirt or foreign objects on your cat’s cornea.

Cherry eye is caused when this gland becomes loose and starts to protrude outside the third eyelid.

This can cause the nictitan gland to become swollen and inflamed. which can cause your cat’s third eyelid to show.

Although this problem is more common in dogs, it can happen to cats too.

The best way to solve cherry eye is with surgery to correct the position of the nictitans gland.

Another option is to remove the gland but that will result in another issue called dry eye when there isn’t enough tear production.

6. Eye Injury Or Infection

Direct injury to your cat’s eye can cause the third eyelid to show.

Your cat can injure its eye by getting into an accident or getting into a fight with another cat or animal. This can cause your cat to puncture or scratch its cornea which can lead to a corneal ulcer.

It is also best to keep your cat indoors to prevent it from getting into fights and accidents outside.

Your cat can also get an eye infection from foreign objects being stuck in the eye.

Common symptoms of an eye problem include:

  • Eye discharge
  • Watery eyes
  • Cloudy cornea
  • Appearance of third eyelid
  • Unable to fully open the eyes
  • Eye protruding out of the socket

Any eye issue in your cat that doesn’t go away after a few days needs to be checked by the vet.

The vet will be able to prescribe eye drops or antibiotics like penicillin for your cat if there’s a bacterial infection.

Please do not wait to get your cat’s eyes treated. Any damage to your cat’s eye can cause corneal ulcers or loss of sight if left untreated.

7. Horner’s Syndrome

Horner’s syndrome in cats is a neurological disorder that affects your cat’s facial muscles and the appearance of the eyes.

This medical condition is caused by damaged nerves that lead to the cat’s face that a neck injury, tumors, ear infection, spinal injury and neurological disorders can bring about.

Symptoms include:

  • Droppy upper eyelids
  • Eyes are sunken in
  • Protrusion of the third eyelid
  • Cross-eyed

If an infection or injury causes Horner’s syndrome, your cat will require medication or surgery to recover.

In many cases, the vet will ask you to just observe your cat as this problem can clear up and go away on its own over time.

8. Glaucoma

Glaucoma is a serious eye condition that results from an increase in pressure in your cat’s eye.

Pressure within the eye, also known as intraocular pressure (IOP), is essential for maintaining the shape of the eye and enabling it to function properly.

But when the pressure gets too high, it can damage the optic nerve and cause blindness in cats.

Symptoms of glaucoma in cats include:

  • Pain in the eye
  • Redness and inflammation
  • Cloudy cornea
  • Loss of vision
  • Third eyelid showing

The increased intraocular pressure can cause the third eyelid to become more visible or partially cover the eye.

This may be due to the cat’s attempt to protect the eye from further irritation or pain,

Glaucoma is a serious eye problem and needs immediate medical attention or your cat might go permanently blind.

Should I Be Worried If My Cat’s Third Eyelid Is Showing?

Yes and no.

The consensus amongst cat owners is that if the cat’s third eyelids are showing, the cat is sick or in discomfort.

More often than not, that would be the case.

But based on my many years of keeping cats, there will be times when your cat’s third eyelid could be showing without any other worrying symptoms.

We will take a look at both scenarios that can cause the appearance of your cat’s third eyelid

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