Cat Third Eyelid: A Fascinating Feature You Might Not Know About

Cats possess a third eyelid, called the nictitating membrane, which protects and moistens their eyes, but its visibility can indicate health issues requiring veterinary attention.

Cats have a secret weapon in their eyes – a third eyelid! This thin, see-through membrane helps keep their peepers protected and moist.

You may spot it as a pale pinkish film sliding across your kitty’s eye.

The third eyelid in cats is also called the nictitating membrane.

It sits in the inner corner of the eye and can sweep across to cover the whole eyeball. This special eyelid shields the eye from scratches and dust while spreading tears to keep things lubricated.

Sometimes a cat’s third eyelid may become visible when it shouldn’t be.

This can point to health issues like eye disease, dehydration, or injury.

If you notice your cat’s third eyelid showing often, it’s best to check with a vet to make sure everything’s okay.

Anatomy of the Cat’s Third Eyelid

Cats have a special eye feature called the third eyelid.

It helps protect their eyes and keep them moist.

Let’s look at how it’s built and works.

Structure and Function

The third eyelid, also known as the nictitating membrane, is a thin, clear layer in the inner corner of a cat’s eye.

It’s made of tissue and moves sideways across the eye.

This membrane has tiny glands that make tears to keep the eye wet.

The third eyelid acts like a shield.

It guards the eye from scratches and dirt.

When a cat blinks, this eyelid sweeps across the eye, cleaning it and spreading tears.

Cats can’t control this eyelid on purpose.

It moves on its own when needed.

If you see it often, it might mean your cat isn’t feeling well.

Comparative Anatomy Across Species

Many animals have third eyelids, not just cats.

Dogs, birds, and reptiles have them too.

But they can look and work a bit differently.

In birds, the third eyelid is clear.

It helps them see while flying through the air or diving into water.

For dogs, it’s similar to cats but might show more often.

Some animals, like camels, have third eyelids that help keep sand out of their eyes.

Fish and sharks have a different type that protects their eyes underwater.

Humans don’t have a full third eyelid.

We just have a small bit of tissue in the corner of our eyes.

It doesn’t move or protect our eyes like in other animals.

Common Third Eyelid Conditions

Cats can face several issues with their third eyelid.

These range from mild to serious and may need vet care.

Haw’s Syndrome

Haw’s syndrome is when a cat’s third eyelids show in both eyes.

It often happens with no other eye problems.

The cause isn’t fully known, but it may link to gut issues.

Most cats with Haw’s syndrome don’t need treatment.

The third eyelids usually go back to normal on their own.

If not, a vet can help find the cause.

Cats with this problem might seem fine otherwise.

But some may eat less or have loose stools.

If you see these signs, it’s best to call the vet.

Cherry Eye

Cherry eye happens when a tear gland in the third eyelid swells up.

It looks like a red bump in the corner of the eye.

This is more common in dogs but can affect cats too.

The swollen gland can block the cat’s vision.

It may also cause dry eye if left untreated.

Vets often suggest surgery to fix cherry eye.

After surgery, most cats recover well.

But there’s a chance the problem could come back.

Owners should watch their cat’s eyes after treatment.

Conjunctivitis

Conjunctivitis is an eye infection that can make the third eyelid show more.

It causes red, swollen eyes that may have discharge.

Cats can get conjunctivitis from viruses, bacteria, or allergies.

Some signs include squinting, rubbing the eyes, and being less active.

Vets treat conjunctivitis based on the cause.

They might use eye drops or pills.

It’s important to finish all medicine, even if the cat looks better.

Prolapse of the Tear Gland

This happens when the tear gland pops out of place.

It’s like cherry eye but can be more serious.

The gland might look swollen or red.

If not treated, it can lead to dry eye.

This is because the gland can’t make tears properly when it’s out of place.

Vets usually fix this with surgery.

They put the gland back where it belongs.

After surgery, cats need extra care to help their eyes heal.

Indications of Third Eyelid Visibility

The cat's eyes are partially closed, with a thin, translucent membrane visible in the inner corner of each eye

A cat’s third eyelid can become visible due to various reasons.

Some are normal, while others may signal health issues.

Let’s look at what to watch for with this unique feline feature.

Normal vs. Concerning Signs

Cats’ third eyelids may show slightly when they’re very relaxed or sleepy.

This is usually not a problem.

But if the eyelid stays visible for a long time, it could mean something’s wrong.

Stress or illness can make a cat’s third eyelid more noticeable.

If your cat seems upset or sick, check their eyes.

Dehydration is another reason the third eyelid might show.

Make sure your cat has plenty of fresh water.

Some health issues can cause the third eyelid to appear.

These include:

If you see redness, swelling, or discharge along with the visible third eyelid, call your vet.

These could be signs of eye disease.

Sometimes, tiny bits of dust or fur can irritate a cat’s eye.

This might make the third eyelid show up.

If it doesn’t go away after a few blinks, it’s best to have a vet take a look.

Diseases Affecting the Third Eyelid

Cats’ third eyelids can be affected by various health issues.

These problems can range from simple infections to more serious conditions like autoimmune disorders and tumors.

Infections and Inflammations

Eye infections are common issues that can impact a cat’s third eyelid.

Bacterial and viral infections can cause the third eyelid to become inflamed and more visible.

Conjunctivitis, an inflammation of the eye’s surface, often affects the third eyelid.

This condition can make the eyelid red, swollen, and more noticeable.

Feline herpesvirus is a frequent cause of eye problems in cats.

It can lead to inflammation of the third eyelid and other eye tissues.

Chlamydia, another infectious agent, can cause eye inflammation and make the third eyelid more prominent.

Autoimmune Disorders

Some autoimmune conditions can affect a cat’s eyes, including the third eyelid.

These disorders occur when the body’s immune system mistakenly attacks its own tissues.

Uveitis, an inflammation of the eye’s middle layer, can sometimes involve the third eyelid.

This condition can be painful and may cause the third eyelid to become more visible.

Haw’s syndrome is a condition where both third eyelids protrude without other eye problems.

While not strictly an autoimmune disorder, it’s thought to be related to the immune system.

Neoplastic Conditions

Cancer can affect a cat’s third eyelid, though it’s not common.

Tumors in this area can cause the third eyelid to become enlarged or misshapen.

Squamous cell carcinoma is one type of cancer that can occur on the third eyelid.

It often appears as a small, raised growth.

Lymphoma, a cancer of the lymphatic system, can sometimes involve the third eyelid and surrounding tissues.

If a cat’s third eyelid looks abnormal or is constantly visible, it’s important to have a vet check it out.

Early detection and treatment of these conditions can help prevent more serious problems.

Signs and Symptoms of Eye Distress

Cats can show various signs when their eyes are in distress.

These symptoms can range from mild discomfort to more serious issues like infections.

It’s important to watch for changes in your cat’s eyes and behavior.

Recognizing Discomfort

Cat’s third eyelids showing is often a sign of eye discomfort.

This thin membrane may appear in the inner corner of the eye.

Other signs of eye distress include:

  • Excessive blinking or squinting
  • Pawing at the eyes
  • Keeping one or both eyes closed
  • Avoiding bright lights

Cats might also rub their face against furniture or their owner’s legs when feeling eye discomfort.

Tearing or watery eyes can be another indicator of irritation.

Identifying Infections

Eye infections in cats can cause more severe symptoms. Conjunctivitis, also known as pink eye, is a common issue.

Signs of infection include:

  • Redness in the whites of the eyes
  • Swollen eyelids
  • Thick, colored eye discharge (yellow, green, or white)
  • Crusty material around the eyes

In some cases, cats with eye infections may become lethargic or lose their appetite.

Corneal ulcers can cause cloudiness in the eye.

If left untreated, eye infections can lead to more serious problems.

Protective Mechanisms of the Third Eyelid

Cats have a special defense system in their eyes.

The third eyelid works hard to keep their eyes safe and moist.

It moves quickly to block out bad stuff and spread tears around.

Response to Debris and Dust

The third eyelid in cats acts like a shield.

It sweeps across the eye to remove dirt and dust.

This happens fast, often before we can even see it.

When something flies towards a cat’s eye, the third eyelid jumps into action.

It slides up to cover the eye surface.

This stops harmful objects from touching the eye.

The eyelid also helps catch tiny bits of dirt.

It wipes them away before they can cause harm.

This keeps the cat’s vision clear and prevents eye scratches.

Tearing and Hydration

The third eyelid does more than just block stuff out.

It also helps keep the eye wet and comfy.

This eyelid has a special gland that makes tears.

These tears spread over the eye when the third eyelid moves.

They form a thin layer called the tear film.

This film is super important.

It keeps the eye moist and helps wash away any small bits of dust.

The tears also have stuff in them that fights germs.

This helps protect the eye from infections.

When a cat blinks, the third eyelid helps push tears all over the eye surface.

Third Eyelid Protrusions: Diagnosis and Treatment

When a cat’s third eyelid protrudes, it can be concerning for pet owners.

A vet exam is key to finding the cause and getting proper treatment.

Some common treatments can help resolve the issue.

Veterinarian Examination Process

The vet will start by looking closely at the cat’s eyes.

They’ll check for signs of trauma or injury.

The exam may include:

• Checking eye pressure
• Looking for foreign objects
• Testing tear production
• Examining eye reflexes

Blood tests might be done to check for health issues.

The vet may also ask about recent changes in the cat’s behavior or diet.

If needed, the vet might use special tools to get a better look at the eye.

This helps them spot any hidden problems that could be causing the protrusion.

Common Treatments

Treatment depends on what’s causing the third eyelid to show.

Here are some typical approaches:

  1. Eye drops or ointments to reduce swelling
  2. Removal of any foreign objects
  3. Antibiotics for infections
  4. Surgery for severe cases

In some instances, the vet might suggest waiting to see if the problem clears up on its own.

This is often the case with Haw’s syndrome, where both third eyelids may show without other symptoms.

For ongoing care, the vet may teach owners how to apply eye medication at home.

Regular check-ups can help make sure the treatment is working well.

Surgical Interventions for Third Eyelid Issues

Sometimes a cat’s third eyelid needs surgery to fix problems.

Vets can do different operations to help cats see better and feel more comfortable.

When Surgery Is Needed

Cats may need surgery for their third eyelid if other treatments don’t work.

One common issue is cherry eye, where the gland behind the third eyelid pops out.

This can look like a red bump in the corner of the eye.

Another problem is when the third eyelid, also called the palpebra tertia, sticks out too much.

This is called prolapse.

Sometimes, a dermoid cyst can grow on the third eyelid and need to be removed.

Vets will check the cat’s eyes carefully before deciding on surgery.

They want to make sure it’s the best choice for the cat.

Post-Operative Care

After surgery, cats need extra care to help them heal.

The vet might give the cat a special collar to stop it from scratching its eyes.

Eye drops or ointments are often needed to prevent infection and help with healing.

Cats should stay calm and quiet for a few days after the operation.

This means keeping them inside and limiting playtime.

The owner needs to watch for any signs of problems, like more swelling or discharge from the eye.

Regular check-ups with the vet are important to make sure the cat is getting better.

Most cats recover well from third eyelid surgery and can see clearly again.

Preventing Third Eyelid Complications

A cat with its third eyelid visible, receiving medical treatment from a veterinarian

Keeping your cat’s third eyelid healthy is important.

Good care and the right diet can help avoid problems.

Routine Care and Checks

Cat parents should check their pet’s eyes often.

Look for any redness, swelling, or discharge.

If the third eyelid is showing, it might mean there’s an issue.

Clean around your cat’s eyes gently with a soft, damp cloth.

This helps remove dirt that could cause irritation.

Be careful not to touch the eye itself.

Take your cat to the vet for regular check-ups.

The vet can spot early signs of eye problems.

They might suggest special eye drops to keep the eyes moist and healthy.

Nutritional and Environmental Factors

A good diet helps keep a cat’s eyes healthy.

Feed your cat food rich in vitamins A and E. These nutrients support eye health.

Keep your home dust-free.

Dust can irritate a cat’s eyes and lead to third eyelid issues.

Use air filters to clean the air.

Don’t let your cat near harsh chemicals or smoke.

These can hurt their eyes.

Make sure your cat has clean, fresh water to drink.

This helps keep their eyes moist.

If you have plants, check that they’re safe for cats.

Some plants can cause eye irritation if a cat rubs against them.

When to Seek Veterinary Care

A cat with a visible third eyelid, squinting or pawing at its eye, while a concerned owner looks on

Cats’ third eyelids can signal health issues.

It’s key to know when to get help from a vet.

Look out for changes in your cat’s eyes and general health.

Common Causes for Concern

If your cat’s third eyelid is visible for more than a day, it’s time to call the vet.

This can point to eye infections or other health problems.

Keep an eye out for redness, swelling, or discharge around the eyes.

Upper respiratory infections often cause eye issues in cats.

If your kitty is sneezing or has a runny nose along with eye problems, don’t wait to get help.

Lethargy and loss of appetite paired with visible third eyelids are red flags.

These signs might mean your cat is dealing with a fever or illness.

Emergency Signs in Eye Health

Some eye issues need quick action.

Get to the vet right away if you see that your cat’s eye looks cloudy or has changed color.

Urgent signs include squinting, excessive blinking, or keeping one eye closed.

These behaviors often mean your cat is in pain.

Swollen or bulging eyes need immediate care.

This could be a sign of glaucoma or other serious conditions.

Don’t delay if you notice any trauma to your cat’s eye area.

Even small injuries can lead to big problems if not treated quickly.

Remember, when in doubt, it’s always best to check with your vet.

They can spot issues you might miss and keep your cat’s eyes healthy.