When your cat squints at you, they’re most likely telling you they feel safe. That slow, half-closed eye look is one of the clearest ways cats express comfort and trust. It’s sometimes called a “cat kiss” or “slow blink,” and research published in Scientific Reports in 2020 confirmed what cat owners have long suspected: this behavior is a genuine form of positive emotional communication between cats and humans. But squinting doesn’t always mean affection. In some cases, it signals pain or an eye problem, and knowing the difference matters.
The Slow Blink: A Cat’s Way of Saying “I Trust You”
Cats communicate largely through body language, and eye contact carries a lot of weight in the feline world. A hard, unblinking stare is threatening. It’s what cats do before a fight. Squinting is the opposite signal. By narrowing their eyes or slowly closing and reopening them, a cat is essentially saying, “I’m relaxed enough around you to let my guard down.” Closing your eyes, even partially, makes you vulnerable. When a cat does this while looking at you, it’s a deliberate display of trust.
This makes sense from an evolutionary perspective. Animals that are on alert keep their eyes wide open, scanning for threats. Looking away, yawning, blinking slowly: these are all calming signals that communicate, “I don’t see you as a threat or a target.” Angry or frightened cats glare with wide, unblinking eyes. The slow squint is the biological inverse of that response.
What the Research Actually Found
A 2020 study from the University of Sussex tested whether the slow blink is real communication or just something cat owners imagine. The researchers ran two experiments. In the first, they had cat owners slow-blink at their cats and compared the cats’ responses to a control condition where owners were in the room but didn’t interact. Cats produced significantly more eye-narrowing movements when their owners slow-blinked at them, roughly double the rate compared to no interaction.
The second experiment went further. This time, a stranger (the experimenter) either slow-blinked at the cat or sat with a neutral expression. Cats were more likely to approach the stranger after receiving slow blinks. They also returned the gesture more frequently. This is notable because cats are famously wary of unfamiliar people, yet the slow blink was enough to shift their behavior toward friendliness. The researchers concluded that slow blink sequences function as positive emotional communication between cats and humans.
How to Slow Blink Back
You can use the slow blink to build trust with your own cat, or even with cats you’re meeting for the first time. The technique is simple but the timing matters. Wait for a calm moment when your cat is relaxed and already looking in your direction. Don’t loom over them. Sitting or crouching at their level makes you less intimidating.
Relax your face, then gently close your eyes for one to two seconds. Open them slowly. Don’t stare directly at the cat before or after. The whole point is to signal that you’re at ease, so a tense or focused expression defeats the purpose. If your cat squints or slow-blinks back, you’ve successfully exchanged the feline equivalent of a smile. Some cats respond immediately, while others need repeated calm interactions before they’ll reciprocate.
When Squinting Means Something Else Entirely
Not every squint is a love letter. Context tells you which kind you’re seeing. A relaxed cat slow-blinking at you from across the room, with soft body posture and normal-sized pupils, is communicating affection. But squinting paired with other body language changes can mean very different things.
Pain
The Feline Grimace Scale, a validated tool veterinarians use to assess pain in cats, includes “orbital tightening” as one of its five key indicators. This looks like persistent narrowing of the eye area, where the space between the eyelids shrinks to less than half the eye’s width, or the eyes are held tightly shut. When a cat is in pain, squinting typically appears alongside other signs: ears rotated outward, a tense or flattened muzzle, whiskers pushed forward and stiff, and the head held low. A cat that’s squinting from pain won’t look relaxed. Their whole face and body look tense.
Eye Problems
Squinting in one eye is almost always a medical issue rather than a social signal. A cat blinking affectionately uses both eyes. One-sided squinting, especially with watery discharge, cloudiness, redness, or pawing at the face, can indicate a corneal ulcer, conjunctivitis (pink eye), or other eye conditions that need veterinary attention. Eye ulcers in particular can worsen quickly, so persistent single-eye squinting warrants a prompt vet visit.
Aggression
During a confrontation, cats may narrow their eyes as protection against potential injury from claws or bites. This looks very different from the soft, drowsy squint of affection. An aggressively squinting cat will have a stiff body, flattened ears, a puffed tail, and pupils that are either very dilated or narrowed to slits. The overall posture is tense and forward-leaning, not relaxed.
Flat-Faced Breeds Squint More Often
If you have a Persian, Exotic Shorthair, or another brachycephalic (flat-faced) breed, you may notice more frequent squinting that isn’t related to mood at all. These breeds are prone to chronic eye issues because of their facial structure. Shallow eye sockets and compressed tear ducts lead to ongoing irritation, increased light sensitivity, and excessive tearing. Cats with these problems often hold their eyes partially closed and blink more frequently as a response to discomfort. If your flat-faced cat squints often and also rubs at their face or has visible discharge, it’s likely a structural issue rather than affection. Your vet can help manage the discomfort.
Reading the Full Picture
The key to interpreting your cat’s squint is looking at everything else happening at the same time. A slow blink of affection comes with a loose, relaxed body. The ears are in a neutral or slightly forward position. The tail is still or gently swaying. The cat may be purring, kneading, or settling into a loaf position nearby. The whole animal looks at ease.
A squint that signals trouble comes packaged with tension somewhere: a rigid body, flattened ears, dilated pupils, a tucked or puffed tail, or visible attempts to rub or scratch the face. Duration matters too. The affectionate slow blink is a brief gesture, a moment of eye contact followed by that drowsy half-close. A cat holding its eyes narrowed for long stretches, especially while withdrawn or hiding, is more likely uncomfortable than content.
Most of the time, when your cat looks at you through half-closed eyes from the comfort of the couch, it’s one of the warmest things they can offer. Cats don’t have the facial muscles that dogs or humans use for expressive grins and greetings. The slow blink is their version, and it’s one you can give right back.