Do Cats Blink?

Most of a cat’s day is spent sleeping, so naturally their eyes are completely closed during that time. But what about when they’re not napping?

Do cats blink like we do? How can you tell if your cat is blinking or squinting, or if something is in their eye? When your cat blinks, does it mean something else is going on, or that your cat is trying to communicate with you?

Do Cats Blink to Clear Their Eyes?

Cats do indeed blink, just like their human counterparts, though their eyelid movements and biology differ from ours in many ways.

Cats have both upper and lower eyelids that cover and protect their eyes. When a cat blinks, both upper and lower eyelids move toward each other, but they don’t usually completely close like ours do. Instead, it may look like your cat is squinting.

Cats also have a third eyelid, called a nictitating membrane, that helps with tear production through special glands located in the membrane. The nictitating membrane is pink and located in the inside corner of the eye, under the upper and lower eyelids. This membrane is very thin and can move very quickly.

When a cat blinks, partially closing their upper and lower lids, the nictitating membrane moves diagonally across the eye very quickly. It’s unlikely you’ll be able to see the membrane moving. Instead, it may simply look like your cat is squinting.

These three eyelids work together to protect your cat’s eyes, but blinking in cats doesn’t serve the same purpose it does in humans. When we blink, our eyelids spread tears to keep the eye surface moist and remove debris. Cats, however, don’t blink to remove tears. Instead, their tears evaporate after particles are removed from the eye. This allows cats to get the benefits of blinking without ever fully closing their eyes.

Do Cats Blink to Protect Their Eyes?

A cat’s third eyelid can also extend upward to protect their eyeball from trauma. For example, when a cat moves through tall grass, or when a cat is capturing prey, their third eyelid elevates to avoid scratching their cornea.

One school of thought is that the membrane of this eyelid is thin enough for cats to be able to see through it, which gives them an advantage when hunting prey.

What Does It Mean When a Cat Slow Blinks or Winks at You?

Cats also use their eyes, body language, and facial expressions to convey a variety of messages, including affection and aggression.

When a cat closes their eyes, it’s associated with positive emotional communication. “Slow blinking” is a term used to describe when cats hold their eyelids almost closed and perform a slow wink in one or both eyes. It typically involves a series of half-blinks and eyelid narrowing.

Slow blinking in cats has been shown in studies to occur more frequently as a response to human slow-blinking stimuli. One study found that cats were more likely to approach a person if that person provided a slow-blink stimulus than when they had a neutral expression on their face.

Closing the eyes in the presence of another animal (including humans) is considered the ultimate signal of trust. If your cat slow blinks or winks at you, it means they are content and feel no danger in your presence. They may even copy this behavior if you start slowly winking at them when they are looking at you.

Slow-blinking behavior is often coupled with rolling over and displaying the belly, or perhaps a slow purring noise. Again, this shows that a cat feels comfortable and safe. If your cat slow blinks or winks at you, return the favor so they feel the love and affection returned. Cats are funny creatures, but if you are chosen to be loved by one, that bond is lifelong.

Cats who feel threatened or who want to assert dominance over another animal will often hold an unblinking stare. For more submissive cats, this intimidating gesture can cause them to turn around and leave the area, thus allowing the dominant cat to control their territory.

What Does It Mean When a Cat Is Squinting?

There are some medical causes of increased blinking and/or squinting of a cat’s eyes. These include inflammation in or around the eye and are often seen secondary to pain or discomfort. You may see increased discharge or tear production from the affected eye.

Elevation of the third eyelid can also be noted due to pain in the eye, chronic dry eye, growths on the third eyelid, and/or viruses. This happens when the eye itself retracts into the cat’s skull, causing the third eyelid to elevate.

Certain disorders can lead to increased blinking or squinting, such as:

Corneal ulceration
Lacerations
Uveitis
Glaucoma
Foreign objects in the eye
Growths and/or abnormal growth of eyelashes
Facial nerve paralysis (a medical condition that can lead to an inability to blink, including the third eyelid, which can eventually cause chronic dry eye, infections, and pain)

If you notice the following, contact your veterinarian to discuss options for examination, diagnostic testing, and treatment:

Your cat cannot blink one or both eyes
Your cat is blinking frequently, squinting, or holding one eye or both eyes completely shut
Increased tear production or tear staining on your cat’s fur
A green/yellow or bloody discharge from their eye(s),
Pawing at the eye(s) and/or redness/cloudiness in or around their eye(s)