By: Author Amanda OBrien
In this post:
- The 10 most common reasons cats keep one eye closed, from minor irritation to serious health issues
- When a partially closed eye needs immediate veterinary attention versus watching at home
- Practical tips for checking your cat's eye safely and supporting their comfort while healing
- Answers to the most common questions about cat eye behavior and blinking patterns
Everybody knows cats like to blink slowly at the people they trust — it's often nicknamed a "cat kiss," and most agree it's a sign of affection. An occasional wink is completely normal too. So why is my cat keeping one eye closed?
That's a different question. If you notice your cat's eye is consistently shut — not the odd wink, but held closed or squinted for hours, getting worse, or paired with any discharge or swelling — that's your cat telling you something isn't right. The key thing to watch for is consistency: a cat blinking one eye occasionally is normal; a cat holding one eye closed for an extended period is not.
Image by mint910630 from Pixabay
Cats' eyes, like ours, are delicate — and cats are also very good at hiding pain, so a closed eye is often one of the clearest signals you'll get that something needs looking at. Here are the 10 most common reasons.
Why is My Cat Keeping One Eye Closed? 10 Possible Reasons
The causes range widely — from something as simple as a bit of grass or dust in the eye, to more involved conditions that need ongoing veterinary management.
1. Cataracts
A cataract is a clouding of the eye's lens, and it usually appears as a hazy or white patch over the pupil. As the cloudiness progresses, it blocks light from reaching the back of the eye, which can lead to partial or complete vision loss.
The most common cause of cataracts in cats is chronic inflammation inside the eye (called uveitis) — often linked to viral infections like feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), feline infectious peritonitis (FIP), or feline herpesvirus. Genetics, trauma, and aging can also play a role. Interestingly, while diabetes is a common cause of cataracts in dogs, diabetic cataracts are actually rare in cats.
Cataracts themselves aren't usually painful, but the underlying inflammation causing them can be — so a vet visit is worthwhile to identify the cause and check whether the eye needs treatment. Surgery is an option in some cases; many cats also adapt well to partial vision loss with support at home.
2. Eye Infection
Eye infections are one of the most common reasons for a closed or squinting eye. They can be bacterial or viral, with conjunctivitis (inflammation of the tissue around the eye) being the most familiar result.
Feline herpesvirus (FHV-1) is the single most common cause of conjunctivitis in cats — most cats are exposed to it at some point, and it can flare up again later in life, especially during stressful periods. Signs include redness, discoloration, excessive tearing, and often a green or yellow discharge. A cat will usually hold an infected eye closed due to pain or light sensitivity.
Mild cases sometimes settle on their own within a couple of weeks, but because it's hard to tell a mild case from something more serious without an exam, it's worth having your vet take a look — particularly if the discharge is thick or colored, or if it's not improving.
Image by Sa Ka from Pixabay
3. Corneal Ulcer
A corneal ulcer is a wound or erosion on the clear surface of the eye, often caused by trauma, a scratch, or feline herpesvirus. It's usually accompanied by redness, cloudiness, discharge, and noticeable light sensitivity.
Vets diagnose ulcers using a fluorescein dye test — a stain that highlights damaged tissue in green under blue light, since many ulcers aren't visible to the naked eye. Simple, superficial ulcers often heal within about a week with prompt treatment; deeper or infected ulcers can take several weeks and need more intensive care, sometimes including surgery. Left untreated, ulcers can worsen quickly, so this is one condition where a same-day vet visit is worth it rather than waiting to see.
4. Dry Eye
Keratoconjunctivitis sicca (KCS), or dry eye, happens when a cat's eyes don't produce enough tears to keep the surface clean and lubricated naturally.
The eye often looks dry and may have a yellow discharge, along with noticeably excessive blinking. Vets can prescribe medication to help manage tear production and keep the eye comfortable long-term.
5. Allergic Conjunctivitis (Pink Eye)
Conjunctivitis isn't always infectious — cats can also develop it from allergies, which can be just as uncomfortable as a bacterial or viral cause.
Image by Jordan Al from Pixabay
6. Foreign Objects
Cats who spend time outdoors, or who like to explore under furniture, can easily get dust, grass seeds, or debris in their eye. This usually causes swelling, redness, and squinting.
Sometimes tears will wash the object out on their own — but it's still worth a vet check, since a foreign object can scratch the cornea on its way in (or out), and it's not always possible to tell from the outside whether that's happened.
7. Glaucoma
Glaucoma happens when fluid builds up inside the eye and can't drain properly, due to swelling, blockage, an untreated infection, injury, or in some cases a tumor. Some breeds are also more predisposed to it (see the breed section below).
Glaucoma is genuinely painful, and you may notice behavior changes alongside the closed eye — hiding, or seeming to cower for no clear reason. It needs prescription treatment from a vet, and prompt care gives the best chance of protecting your cat's vision. Left untreated, it can cause severe and permanent damage, including loss of the eye.
8. Injury To Your Cat's Eye
Eye injuries are fairly common, especially in kittens who scratch and roughhouse as they learn to play. A scratch to the cornea can become infected if it isn't treated, leading to swelling, discharge, and a closed eye.
Image by Alexa from Pixabay
9. Problems With Your Cat's Eyelid
Sometimes the issue isn't the eye itself but the eyelid — a condition called blepharitis, where the eyelid becomes flaky or swollen and prevents the eye from opening fully.
Mild cases can sometimes be managed with regular warm-water bathing or a vet-recommended eye cleaner, but if it persists, it's worth a check-up rather than continuing to self-manage.
10. Entropion
Entropion is a condition where the eyelid rolls inward, causing the lashes and skin to rub against the eyeball and cornea. If it's causing ongoing irritation and pain, your cat may keep the affected eye closed for long periods. This one typically needs surgical correction rather than resolving on its own.
A Note on Underlying Viral Infections
A few of the causes above — cataracts, chronic conjunctivitis, and recurring corneal ulcers in particular — can trace back to a handful of common feline viruses: feline herpesvirus (FHV-1), FeLV, FIV, and FIP. These infections don't always cause obvious symptoms elsewhere, and eye problems are sometimes the first visible sign.
If your cat's eye issue is recurring, doesn't have an obvious cause (like an injury), or comes with other symptoms like lethargy or reduced appetite, your vet may recommend testing for one of these as part of working out the underlying cause — this is a routine part of investigating persistent eye problems, not a sign that something catastrophic is necessarily going on.
Eye Problems in Certain Cat Breeds
These issues aren't limited to specific breeds, but some cats are more prone to certain eye problems than others — particularly brachycephalic (flat-faced) breeds, whose head shape can make it harder to produce enough tears to naturally wash the eye.
Photo by Tranmautritam of Pexels
Brachycephalic Cats
These breeds have a shorter snout and a more compact skull shape — you can read more about the look in our guide to flat-faced cat breeds. Breeds that fall into this group and may be more prone to tear-production issues include:
- Scottish Fold
- Persian
- Munchkin
- Himalayan
- Exotic Shorthair
- Burmilla
- British Shorthair
Exotic Shorthair cat
Tips for When Your Cat Is Blinking or Squinting One Eye
- Tell a normal blink from a real problem. An occasional wink or a slow, relaxed blink is normal cat communication. An eye that's held shut, squinted tightly, or closing more and more over a few hours is not — that's when to act.
- Don't self-treat. Avoid human eye drops, leftover pet medication from a previous problem, or home remedies of any kind. None of these are a substitute for a proper diagnosis, and some can make things worse.
- Check gently, don't poke. You can look for visible discharge, swelling, or an object on the surface of the eye, but don't try to remove anything lodged in the eye yourself — that's a job for your vet.
- Stop your cat from pawing at it. Rubbing or scratching at an irritated eye can turn a minor issue into a more serious one. Your vet may recommend a protective cone collar if your cat won't leave it alone.
- Know when it's an emergency. Get to an emergency vet the same day for a bulging eye, visible bleeding, sudden severe pain, or if the eye appears to be coming out of its socket. For milder symptoms — slight redness, a small amount of clear discharge, otherwise normal behavior — a same- or next-day appointment with your regular vet is usually appropriate, but don't wait more than a day or two either way.
Why Getting This Checked Quickly Matters
Most causes of a closed eye respond well to treatment when they're caught early — but several of them (corneal ulcers, glaucoma, untreated infections) can get significantly worse within days if left alone, sometimes to the point of permanent vision loss or loss of the eye itself. Since cats are naturally good at masking discomfort, a closed or squinting eye is often one of the more obvious signals you'll get that something is wrong — which makes it worth acting on rather than waiting to see if it resolves.
Common Mistakes to Avoid
- Waiting to see if it clears up on its own. Several of the causes above can worsen quickly, and a day or two's delay can turn a simple fix into a much bigger problem.
- Using human eye drops or ointments. These aren't formulated for a cat's eye and can do more harm than good.
- Trying home remedies instead of a vet visit. There's no reliably safe home treatment for a genuinely closed or painful eye — anything applied without knowing the cause risks delaying proper treatment or irritating the eye further.
- Assuming it's "just how they blink." A cat that's consistently keeping one eye shut isn't winking — that distinction matters for catching a problem early.
- Ignoring frequent pawing at the face. It's easy to mistake this for grooming, but persistent pawing at one eye is usually a sign of discomfort.
Frequently Asked Questions
How long does it take for a cat eye infection to heal with treatment? It varies by cause. Mild viral conjunctivitis linked to feline herpesvirus can settle within a couple of weeks, while bacterial infections often start improving within a few days of starting the right treatment. Your vet will usually want a follow-up to confirm it's healing as expected.
What does it cost to treat a cat eye condition? This varies too much by cause, location, and whether specialist or surgical treatment is needed for us to give a reliable figure here — a simple infection and a corneal ulcer requiring surgery are very different costs. Your vet can give you an accurate estimate once they've examined your cat.
Can a cat lose vision permanently if one eye stays closed for an extended period? Yes, in some cases. Conditions like glaucoma, severe corneal ulcers, and untreated uveitis can all lead to permanent vision loss — or in severe cases, loss of the eye — if they go untreated for too long. The earlier the underlying cause is treated, the better the outcome tends to be.
Are there specific eye drops or medications recommended for different types of cat eye problems? Vets choose from antibiotic, antiviral, anti-inflammatory, or lubricating drops depending on the diagnosis — and the wrong choice can actually make certain conditions (like some ulcers) worse. This is one area where it's genuinely not safe to guess or use a leftover prescription; it needs a proper diagnosis first.
How can I tell if my cat's closed eye is painful versus a minor condition? Signs of pain include squinting tightly rather than gently closing the eye, pawing or rubbing at the face, avoiding bright light, hiding, or reduced appetite. That said, cats are skilled at masking pain, so even a seemingly minor closed eye is worth having checked rather than assumed to be nothing.
Next Steps
- Book a vet visit. Same day for pain, bleeding, bulging, or sudden severe symptoms; within a day or two for anything milder.
- Don't medicate first. Skip human eye drops or old prescriptions — let your vet diagnose before treating.
- Prevent self-trauma. Keep your cat from pawing at the eye until they've been seen.
- Note the details. When you first noticed it, whether it's one eye or both, and whether it's getting better or worse — all useful information for your vet.
- Ask about breed risk. If you have a brachycephalic breed, ask your vet about routine tear-production checks as part of regular visits.
Final Thoughts on Why Your Cat is Keeping One Eye Closed
It pays to be observant with your cat. They tend to hide it when something's wrong, and something as subtle as a closed eye can easily go unnoticed if you're not paying attention.
Don't ignore it — try to get a handle on the cause as soon as you can, since letting a problem go untreated can lead to more serious, longer-term damage. That said, many of the causes above are common and very manageable once caught. Keep an eye out, so to speak, and hopefully you and your cat can get back to some proper eye contact soon.
Amanda created and owns The Discerning Cat. A lifelong cat lover she is the proud parent of two Siberian cats, Alexei and Vladimir. She is passionate about understanding cats and different cat breeds.
Amanda created and owns The Discerning Cat. A lifelong cat lover she is the proud parent of two Siberian cats, Alexei and Vladimir. She is passionate about understanding cats and different cat breeds.
