Cat Squinting One Eye? Here Are The 13 Most Common Causes


Have you ever wondered why your cat squints one eye? Squinting or keeping the eye half closed is one of the most prominent indicators that something is amiss with the eye. A busy cat owner can detect this irregularity by glancing at their pet.

What are the most likely reasons and conditions for a cat squinting one eye? Many factors could be the reason for this. Let us first become acquainted with what is expected. A healthy cat’s eyes are clear and brilliant, with no discharges.

The conjunctiva is the membrane tissue that lines the upper and lower eyelids and a portion of the eyeball. The conjunctiva is moist and light pink in health, which appears as if the cat has pink eye.

The following are noticeable symptoms of something wrong with the eyes: conjunctival redness, edema, and increased tear production.  You may notice fluid discharges from the eye, which range from watery to thick and sludge.

The third eyelid covers the eye drops slightly near the tear duct. There is cloudiness, and a sticky film may sometimes develop over the eyes. The cat may become light sensitive and blink incessantly, avoiding bright light. The cat may close the injured eye half or completely, causing you to notice that your cat is squinting one eye.

Let’s check what eye issues could be troubling your feline friend in order to understand and possibly prevent problems with your cat’s vision.

Why Is My Cat Squinting One Eye?

The eye is a very fragile organ, and a professional veterinarian can only perform a complete examination of the eyes. If you see your cat squinting one or both eyes, you should immediately schedule an appointment with a veterinarian. The problem must be correctly detected as soon as feasible, and therapy must begin as quickly as possible.

Simple situations, such as a minor corneal scrape, can become infected and difficult. When eye infections go untreated over an extended length of time, they can cause irreversible eye damage and blindness.

Viral upper respiratory infections can worsen eye conditions. You should not try to open your eyes on your own since you will just worsen the damage. In other circumstances, such as serious injuries, he may initially require a sedative or pain treatment. Over-the-counter human pain killers should not be given orally to cats since they are poisonous and can be lethal.

But, let’s see what may be the reasons for your cat squinting one eye.

1. Blepharospasm

a cat wrapped in a blanket squints out of one eye

This is inflammation of the eyelids and the conjunctival membranes that border the eyelids. The eyelids and the borders of the eyelids swell under these situations, giving the cat the appearance of squinting.

Severely damaging the eyelids or conjunctiva can result in blepharitis and conjunctivitis. The cat’s eyes will shut or squint due to the injury’s pain. Trauma can result from a scrape, abrasion, or laceration.

Chemical compounds, BB gun pellets, and small bits of shattered glass are among frequent objects that cause harm to the eyes and their related issues. Allergies, particularly a widespread systemic allergic reaction to inhalant and dietary allergens, can produce redness and swelling of the eyelids and conjunctiva.

 Foreign bodies that irritate the eyelids and conjunctiva can also cause the afflicted eye to squint. The most frequent of them is entropion, a congenital eyelid abnormality. Infections can also cause swelling of the eyelids and conjunctiva. Bacterial infections produce eyelid gland abscesses or a general condition of the eyelids.

A red bump on the border of the eyelid is produced by a feline herpes virus infection of the eyelid’s sebaceous glands. Squinting is described as the involuntary shutting of the eyelids. The disorder generally begins with fast eye blinking and progresses to the closure of the eyelids

2. Conjunctivitis And Blepharitis

This is the inflammation of the eyelids along with conjunctival membranes. When this happens, the margins of the eyelids and the eyelid itself swell, and it seems like the cat is squinting, leading to excessive tearing.

Some physical injuries can cause conjunctivitis and blepharitis to the conjunctiva or eyelids. The cat will close its eyes or squint due to the pain from the injury. The cause of damage could be an abrasion, laceration, or just a scratch. Small pieces of broken glass, chemical substances, or gun pellets can cause trauma to the cat’s eyes.

As we as humans suffer from allergies, cats are no exception. Due to allergies, more precisely food and inhalant allergens, a cat’s eyes can become swollen and red. Even so, if an insect has bitten your cat, that can cause localized allergic reactions and swelling. You may see your cat squinting one eye due to this.

The eyelid and conjunctiva can easily be irritated by foreign bodies, causing one of the affected eyes to squint.

When an eyelid is affected by a foreign object, the condition by the name entropion can happen. What does it mean? It means that the ends of the eyelids are turned inwards, and the eyelashes are constantly rubbing against the cornea.

3. Glaucoma

the cat sits on a wooden platform and squints out of one eye

Glaucoma is a rather serious condition, and bear in mind that this should be treated as soon as possible in order to prevent disfigurement or blindness—glaucoma results from the pressure in the eye, which is full of excess fluid.

Many things can prevent eye fluid from draining, which leads to the excess fluid that causes glaucoma. Glaucoma includes inflammation, tumors, abnormalities, eye trauma, and infections. Some cats can have this due to their genetics; in that case, both eyes can be affected.

If your cat is experiencing glaucoma, you will see that your feline friend shows signs of severe pain; you can see your cat squinting one eye, rubbing it, crying, yowling, and avoiding people. If you look at the eyes, they appear runny, reddish, and cloudy. In severe cases, the eyeball may be swollen as well.

If you notice these signs and think that your cat may have glaucoma, you should take her to the vet asap. There are bigger chances of saving the eye or eyes if the pressure in the eye is reduced sooner. In mild cases, if the underlying cause is solved, glaucoma disappears.

However, more severe cases will require treatment and medications, and the build-up must be stopped and prevented. However, we must note that your cat’s eye may be removed in the worst cases.

4. Cat’s Eye infection

Eye infections are common in cats, primarily due to an upper respiratory infection; unfortunately, those infections spread to the eyes. Only by knowing the underlying cause of the infection can we know whether the eye infections are contagious or not.

Several things can cause eye infections, such as parasites, fungi, bacteria, viral infections, etc. If you see your cat squinting and rubbing its eyes, that might be the first sign that your cat has an eye infection. Sometimes their eyes may be reddish and swollen; they have eye discharge, nasal discharge, and sneezing.

You’ll take your cat to the vet for this kind of eye problem, and the vet will treat the infection causing your cat’s eye issues. When the condition is mild, the vet can treat the symptoms by providing rest, clearing the eyes from the discharge, and putting your cat on a healthy diet with a lot of hydration.

More severe issues may be treated with eye drops, systemic antibiotics, and topical ointments.

5. Corneal Ulcers

Corneal ulcers are a potentially serious condition. It manifests in open sores on the eye’s surface, and that affected part becomes cloudy.

This condition can happen due to eye injuries, anatomical abnormalities, or dry eyes. The causes can also be eye infections that are not cured. You will notice the cloudiness in the affected eye, squinting and rubbing, eye pain, discharge, and redness.

Mild corneal ulcers heal when the underlying cause is treated, but expect your vet to prescribe drops or antibiotic ointment and something for your cat’s pain. If the ulcers are severe, your cat may need eye surgery.

However, corneal ulcers are curable if it’s treated in the right way. If it’s untreated, it can result in disfigurement and blindness.

6. Viral And Bacterial Infection

an adorable kitten with a squint on one eye

If you notice that your cat has runny eyes with green discharge, it is almost 100% certain that your cat suffers from a viral or bacterial infection.

These diseases are usually called Cat Flu, Viral Rhinitis, or Influenza. Viral upper respiratory tract issues are independent; however, bacteria like Bordetella bronchiseptica, Mycoplasma, and Chlamydophila felis can be complicated and affect the cat more severely.

Feline herpesvirus can cause feline Viral Rhinotracheitis, affecting the conjunctiva that will swell the eyelids. Then the discharge will show up, watery and then pus-like. Eye’s of your cat will, let’s say, recover,  but the virus will hide in the tissues. When cats experience stress, flare-ups can happen.

Feline Calicivirus causes the infection with the same symptoms as feline herpesviruses, such as squinting, eye discharges, conjunctivitis, and blepharospasm. Cats with calicivirus can have the condition many times due to other strains.

Feline pneumonitis is a condition that Chlamydophila felis causes. You will notice that your cat has inflamed eyes that become bloodshot and red. The discharge from the eyes can also occur, and Pneumonitis can cause more severe conjunctivitis.

7. Symblepharon

Symblepharon is the condition that can be seen in feline herpesvirus. It manifests in the conjunctival tissue’s adhesion to another or the cornea. Kittens that are 10 weeks to 3 weeks of age are mainly affected by this.

Their eyes seem glued together due to the discharge, which is why it looks like the kitten is squinting one eye. Surgical treatment may be needed; that procedure would separate the glued tissues while maintaining the conjunctival epithelial surface and fornix. This will restore your kitten’s vision.

8. Eye Irritation

Even though the cat’s eyes are a bit different from human eyes, they work similarly. Eye irritation can occur due to eye irritants such as cleaning chemicals, perfume, strong fragrances, dust, and tobacco smoke.

Anything like that may result in the cat’s irritated eye. If those things come in contact with your cat’s eye, it will probably be eye-watering. You can notice your cat squinting one eye or rubbing the affected area, and the affected eye may be red and release discharge.

When you’re sure that irritation is causing your cat these symptoms, try rinsing out your cat’s eyes with some eye-wash solution. Of course, if your cat allows it.

However, those symptoms are similar to those serious conditions, so it would be great to consult with your vet about that. If you notice something is causing your cat’s eye problems and discomfort, remove that irritant from home.

9. Cataract

a cat lies on the pavement and squints out of one eye

A cataract is a cloudy part that manifests in the eye lens. That way, it blocks light, and the light can’t reach the back of the eye. That leads to vision loss and, in more severe cases, blindness.

This condition may be of aging, but it can also cause inflammation of the eye’s uvea or diabetes mellitus. This condition can also result from toxic substances, radiation exposure, or an electric shock. In some cases, it can be because your cat lacks calcium.

The eyes will be cloudy and milky if your cat suffers from a cataract. However, you won’t notice that the cataract has progressed until it seriously impairs vision. Your cat may only show that she can’t see well, like moving slowly in dim lightning, bumping into objects, etc.

But, diabetes mellitus is causing cataracts; your cat may be losing weight, be thirsty all the time, and urinate often.

You should see the vet if you notice any of these symptoms; if age isn’t the reason, it should be treated immediately. The surgical procedure to remove the cataracts is an option, but you may consider seeing if your cat can adapt to vision loss. Just make sure that your cat is now avoiding outdoors and dangerous situations.

10. Keratoconjunctivitis Sicca

The Keratoconjunctivitis Sicca or dry eye symptom is the chronic inflammation of the cornea. Conjunctival tissues are dry because the tear production doesn’t work. But the tears are of great importance; they remove debris and infectious objects from the eye.

When there is no tear formation, the cat’s eye will be constantly irritated, resulting in the cat squinting one eye. The cause of Keratoconjunctivitis sicca is some immune damage to tear-producing glands, or it can be possible that it is a feline herpes virus.

The vet will treat the eye in a way that will stimulate tear production, which will ultimately replace tear film. Therefore, the cornea will be protected from damage.

11. Anisocoria

Anisocoria is the condition where the cat doesn’t have the same size as the pupils. This may show peripheral nerve problems, glaucoma, corneal injury, and inflammation in the eye’s interior or the central nervous system. The affected eye’s eyelid will be droopy, and the cat is frequently rubbing the eye or squinting it.

The treatment of this condition is definitely up to the underlying cause. The vet will choose the treatment specifically for your cat’s individual factors.

12. Uveitis

the cat is sitting on the table

Uveitis is the condition where the front part of the inside of the eye is inflamed, specifically between the iris and the cornea. This will manifest in eyes looking hazy and cloudy.

The bottom of the eye sometimes may be full of red sediment or white-yellowish. With this condition, the eye discharge doesn’t show up; however, the eye may seem watery due to the inflammation.

Uveitis is most commonly caused by something that is outside of the eye, meaning other body parts are ill such as:

• An auto-immune condition

• Diabetes

• Severe infections

• High blood pressure

• Cancer

• Blunt trauma

We advise you to take your cat to the vet as the uveitis can be a symptom of a serious matter.

13. Trauma

Your cat squinting one eye is often the result of some trauma. Especially if you have an outdoor cat, it can also happen to indoor cats, and it can occur due to cats fighting or running into furniture or a fence.

Besides the squinting, the cat’s eye may release some discharge from the eye, which can seem like tears, transparent, thick, or green-yellow. You may also notice the swelling and the redness around the eye. Don’t be surprised if you see your cat’s third eyelid. Sometimes, the scratch on the surface of the eye may be visible.

If your cat’s eye irritation happens this way, it is advised to seek the vet immediately because these things can worsen if infected and cause loss of vision.

How To Prevent Cat’s Eye Problems?

the cat eats food from the bowl

If you wonder how to prevent cat’s eye problems, we are here to help you. First and foremost, the vaccination against the feline calicivirus and feline herpesvirus.

If you want to prevent traumatic injuries, you should watch out for sharp objects in places that are easily reachable to your cat. Your cat may see it as something to play with, and things like needles should be removed.

Also, you must take care of your cat’s diet. Your cat needs to have proper nutrition. The immune system will help your cat fight infections. Also, regular grooming is a must if you have a long-haired cat.

Remember that when your cat is in trouble or has health problems, she tends to hide rather than seek your attention and help. So it is on you, cat owner, to be patient and watch your cat in order to notice those issues that may be troubling your cat. Check your cat regularly to see if there are some unusual things.

It is better to prevent it than cure it, right?

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To Sum It Up

If you notice your cat squinting one eye, frequently blinking, pawing at her eyes, or having watery eyes, seek the vet’s help as quickly as possible.

Why do we say that? Because many of those conditions above have similar symptoms, you can’t just guess which is the proper diagnosis. That’s why you need to seek medical help for your furry friend.

Even if your cat is not showing any eye problems, check it often to prevent such issues from happening in the first place. Good advice is to feed your cat with premium meat-oriented cat food, be up to date with vaccines, and limit her exposure to dangerous situations.

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Meta description: If you’ve noticed your cat squinting one eye, check out 13 possible causes of cat’s eye problems and what you can do to prevent it!

Iram Sharma

Fur-tunare enough to have had cats her entire life, Iram has spent years learning about these fluffy little hunters. Today, Iram is a professional veterinarian and a passionate cat mom who uses her skills to help felines in need. Surrounded by her own feline friends, Iram shares her knowledge and experience with all cat lovers.

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