We love our cats, and we’re always interested in learning more about their behaviors. But what about their eye anatomy? Did you know that cats have excellent night vision? Moreover, they have more eyelids than people.
Like us, our furry companions have two sets of actual eyelids. However, they also have a nictitating membrane called the “third eyelid.” In this article, we’ll discuss your topic in detail, so let’s jump right in!
How Many Eyelids Do Cats Have?
The eye anatomy of cats is just as fascinating as their claw anatomy.
We have two sets of eyelids, while cats have three. Yes, you heard that right, three! Let me break it down for you. So, just like people, cats have one upper eyelid and one lower eyelid, and they pretty much resemble our eyelids.
They’re actually the ones you can see when your feline blinks or closes their eyes. But here’s where it gets interesting: these solitary animals have a third eyelid called a “haw” or a “nictitating membrane.”
Here’s the breakdown:
- Upper eyelid: This is the one you see the most, just like yours. It folds down from the top to cover the eye.
- Lower eyelid: This one folds up from the bottom to meet the upper eyelid. Together, they blink to keep the eye moist and dust-free.
- Third eyelid: This is the bonus feature! It’s a thin, pink fold that hides in the inner corner of the eye near the nose. You might not always see it. It helps remove dirt and keeps the eye extra protected.
Why Do Cats Have 3 Eyelids?
Your cat’s nose isn’t the only special thing about their face. Felines also have a third eyelid for the following reasons:
Built-in protective shield
Your cat’s extra eyelid acts like a barrier against foreign objects. You know how sometimes you get something in your eye, like dust or a stray eyelash? Well, cats face the same problem, but their extra eyelid helps keep things out and protect the eye.
Natural eye drops
This third eyelid also helps your cat’s eyes moist.
If you look closely at your cat’s eyes, you will notice that they’re always bright and shiny. That’s because they’ve got a constant flow of tears to keep them moist and healthy.
But sometimes, especially when they’re active or the weather is windy, their eyes can get dry easily. That’s where the third eyelid comes in handy. It helps keep their eyes moist, kind of like a natural eye drop!
Extra protection
A cat’s third eyelid moves because of the sympathetic nervous system and the muscle cells in the membrane. It actually keeps the eye protected, especially in places like tall grass or during hunting.
Even though cats can’t fully control this eyelid, when needed, the sympathetic nervous system and muscle cells kick in to protect their eyes quickly. This helps keep them safe from harm and boosts their overall well-being.
But why do cats need all this extra eye protection and moisture? Well, it all comes down to their lifestyle and strange behaviors.
A day in the life of a cat includes a lot of exploring. They’re constantly stalking through tall grass or chasing after toys, and all that activity exposes their eyes to dust, dirt, and sharp objects. That’s where their third eyelid kicks in and keeps their eyes safe at all times.
Why is My Cat’s Third Eyelid Showing?
If your cat’s third eyelid is showing, it could indicate different underlying issues, such as the following:
Health issues
This might include eye infections, where bacteria or viruses cause inflammation, making the third eye more visible.
Additionally, injuries, such as scratches or trauma to the eye, can result in your feline’s third eyelid showing as a protective mechanism.
Illnesses like feline upper respiratory infections can also cause swelling and irritation of the eye tissues, making the extra eyelid more apparent.
Finally, irritants like dust, debris, or allergies can cause discomfort in your cat’s eye(s) and expose their third eyelid(s).
Important note: Most cat owners try to prevent boredom in indoor cats by including a laser pointer in their playtime. However, laser pointers can hurt your cat’s eyes if used incorrectly.
If you point the laser pointer directly into your cat’s eye, it might cause severe damage or complete blindness. Keep that in mind when amusing your cat with the laser pointer, and perhaps replace it with safer alternatives or even DIY cat toys.
Stress or discomfort
Stress and feline anxiety caused by changing homes, introducing new pets, or loud noises can also result in your cat’s third eyelid showing. You can tell if your furry friend feels stressed or uncomfortable by reading their body language.
Physical discomfort, such as pain from dental issues or gastrointestinal problems, can also cause stress and make your cat’s extra eyelid more visible.
If you notice signs of disease, such as frequent meowing or eye-watering, schedule a vet appointment right away. Your vet can make some tests, determine the underlying cause, and provide proper treatment.
Final Thoughts
All in all, cats have a third eyelid because they’re extra at everything! Their extra eyelid keeps their eyes extra safe when stalking or hunting in tall grass.
However, cat owners rarely see this additional eyelid, and if you do notice it, you should probably call your vet because it could be a sign of health issues, stress, or discomfort.
