Cat Squinting One Eye: Causes of Irritation and Treatment

Cat Squinting One Eye
Squinting in cats is a sign of irritation and possibly infection.

Some eye problems in cats can be very painful. Injuries and infections can make your cat squint one eye or keep it half closed. Sometimes, the feline will shut or rub the eye to protect it and relieve pain.

The basic cause of eye squinting in cats is inflammation. It can result in signs such as watery eyes, discharge, redness, rubbing, blinking excessively, and a showing third eyelid. Feline eye infections such as blepharitis, conjunctivitis, scratched cornea, glaucoma or even allergies can cause squinting, sneezing and nasal discharge.

Unusually blinking, rubbing of the eyes, redness and holding one eye open or half closed are serious symptoms that your cat has an infected eye. The first thing you need to do is to take her to the veterinarian for a proper checkup. Do not try to soothe the irritated eye at home before she has been diagnosed.

Causes of squinting eyes in cats

There are many reasons why your cat may squint or hold one eye closed. However, this is usually a general sign that the eye is infected or highly irritated. Both viral and bacterial infections can produce similar symptoms. Sometimes the cause may not be very serious and could be something you can manage at home as you will see below.

1. Scratched Cornea

Your cat can get scratched by another cat’s claw during play or in a fight. Scratches can also be caused by thorns or rubbing against a rough surface. While it is not very common, it can result in irritation, swelling, and discomfort in the cornea.

You will notice your pet struggling to keep the injured eye open, and there may be other symptoms such as tearing (watery eyes), redness and excessive blinking or winking.

Most cats will not want you to touch their eye if it is painful. However, if you manage to examine the eye, you might notice that there is a little blood inside. If you notice swelling around the eye, It is possible that the cat has suffered trauma in the eye.

It is important to know that corneal lacerations are very painful and require immediate medical attention. If left untreated, such eye injuries and lacerations can develop into serious conditions such as ulcers.

2. Feline blepharitis

Blepharitis can also affect cats. You might notice its symptoms in one or both eyes depending on the level of infection. Anything that can cause irritation to the eyelid can also lead to blepharitis. However, the most common causes are inflammatory disorders allergies, eye infections, tumors, and even congenital disorders.

Due to the constant irritation, you will notice your feline friend blink in small irregular bursts to relieve the pain. This spasmodic blinking is usually called a blepharospasm.

In some instances where the cat is infected with the feline herpes virus-1 (FHV-1), blepharitis may develop as a secondary complication.

3. Conjunctivitis (pink eye)

Conjunctivitis refers to the inflammation of a cat’s eye membranes. It easily results in a reddened, swollen eye. Conjunctivitis is majorly caused by the feline herpes virus that also causes flu.

Pink eye in cats
Pink eye (conjunctivitis)

To distinguish and identify if this is the cause of squinting eyes in your cat, you should look for other symptoms such as:

  • Sneezing
  • Watery eyes
  • Persistent squinting
  • Difficulty breathing
  • Redness in the eye
  • Eye discharge

The main signs of pink eye in cats generally occur on the third eyelid. According to Dr. Thomas Kern, DVM, associate professor of ophthalmology at Cornell University’s College of Veterinary Medicine:

The signs include squinting, frequent blinking, and the presence of a discharge that, depending on the cause of the conjunctivitis, can be either colorless and watery or thick and dark-colored.

Conjunctivitis is highly contagious, meaning it is easily passed from one animal to another. If your cat interacts with other cats more often, it is possible that they caught the virus from them.

4. Entropion

This is a genetic condition where the edges of the eyelid turn inward and start to rub against the cornea. This usually produces irritation that forces the cat to paw at her eye and constantly squint or blink to protect it.

Some cat breeds and has a higher risk of developing entropion than others. Persians, for example, are said to have a wide head that is short in stature, which increases the risk of entropion. Persians are almost always diagnosed with entropion by the time they reach two years of age.

When this condition presents with an infection, you may notice mucus or a yellow discharge emanating from the corner of the cat’s eye. I always advise parents of such cats to always examine the eyes for any sign of entropion and see a veterinarian as soon as possible for proper diagnosis and treatment.

5. Glaucoma

Another possible reason why your cat is squinting one eye is a condition called glaucoma. It occurs as a result of the accumulation of fluid on the front part of the eye usually just behind the lens. This fluid puts a lot of pressure on the optic nerve. If your cat has glaucoma she will definitely experience pain and may start to blink or even squint one eye. Her vision will also be impaired and with time you may notice blindness in that particular eye.

Since feline glaucoma does not have a specific cure, the veterinarian may give you eye drops that primarily relieve pressure while and steroid medications to reduce inflammation and give your cat relief.

6. Foreign body in the eye

You may already know how it feels if you get a foreign object in your eye. The eye will not stop tearing until you get rid of the foreign objects that are causing the irritation. This is very similar with cats and even dogs. A small particle can enter the eye and force your cat to blink or squint in order to get rid of the foreign body.

Most common particles that enter the eye are dust, sand, glass or even metal particles. Sometimes the irritation of the eye may also come from eyelashes if they start to bend inward towards the cornea causing scratches and all sorts of irritation.

Foreign particles in the feline’s eye can cause blepharospasms, tearing and sometimes swelling. This could be the reason why your cat keeps one eye closed while the other open.

]Note: Attempting to remove some foreign particles from a cat’s eye at home can cause injury and severe pain. The procedure should be done by a qualified veterinarian.

According to Dr. Kirk N. Gelatt, VMD, DACVO, a distinguished professor, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida:

Foreign bodies that adhere to the ocular surfaces are usually removed under topical anesthesia with either vigorous irrigation or small serrated ophthalmic forceps.

7. Allergies

Like humans, cats can also suffer from allergic reactions. Most symptoms in allergic kitties usually present on the skin with itchiness being a prominent sign. Additional symptoms usually include itchy teary eyes, squinting excessive blinking, runny nose, wheezing, and coughing.

Allergies in cats causing watery blinking eyes
Allergies can cause teary squinting eyes in cats

If your cat is allergic she may start reacting to many substances including perfumes, flea medications, some foods, and all sorts of dirt allergens in the house including pollen, mildew, and mold.

Systemic allergic reactions can result from allergens in the air or food, and the most common symptoms are usually itchy eyes that result in the cat squinting or blinking unusually. Another common localised allergic reaction in felines is swelling around the eye.

Other causes

There are other conditions that can change the blinking pattern of your cat’s eyes, or even make her keep one eye closed and the other open. They include:

  • Anisocoria
  • Symblepharon (the adhesion of the palpebral conjunctiva to the bulbar conjunctiva, usually caused by trachoma or trauma)
  • Dry eyes
  • Sensitivity to light (photophobia)


Treatment will depend on the cause of squinting. After examination and diagnosis, your vet will choose the appropriate treatment option to go with.

  • Antibiotic medications may be administered if the inflammation is caused by a bacterial infection (bacterial conjunctivitis).
  • In cases of feline viral pink eye, the infection may go away on its own, though antiviral medications may be given to relieve the symptoms.
  • Your vet may also help you identify the allergens that are causing the inflammation. Usually, the best solution to allergies is to eliminate the irritant, which could be a certain food, perfume, or dirt in the house.
  • Removal of the foreign body in the eye is usually done under anesthesia depending on the severity.
  • Your doctor may also choose to administer cat eye drops that will help soothe the eye and reduce inflammation especially if the squinting of one eye is caused by glaucoma.

The best course of action is to see a vet as soon as you notice there’s something wrong with your pet’s eyes.

Home Care Tips

It is important to note that all cut eye irritations should not be treated at home by the cat owner. Any attempt to treat this at home can easily cause further damage to the cornea. The best you can do at home is to prevent your cat from damaging the eye by constantly pawing and scratching. In this regard, here are a few home remedies and care tips you can try to relieve the inflammation in your cat’s eye.

  • Flush the eye with plain water. When you suspect that the squinting of one eye is caused by dust or dirt, carefully approached the cat, restrain her and flush plain water in her eye a few times. This will get rid of the foreign body that is causing the retention and your cat will be well in a few minutes or hours.
  • Declaw and bandage the paws. Cut your cat ’s claws on the front paws. Go ahead and apply a bandage to those paws as well. This measure will prevent a cat from irritating the eye further.

Remember, scratches and easily cause corneal ulcers that will be much more difficult and costly to treat. If you notice that the feline is still scratching her eyes, take her to the veterinarian as soon as possible.


Can I treat my cat’s eye infection at home?

Whether with natural antibiotics or over the counter options, should never try to treat your cat eye infection at home. There are various diseases that can produce similar symptoms. Without a proper diagnosis, you may not know exactly what your furry friend is suffering from.

Is the cat’s eye infection contagious?

Both bacterial and viral pink eye infections are highly contagious in cats. These can be transmitted from one cat to another through direct contact.

Do cats blink one eye at a time?

Felines have a third eyelid, also called the nictating membrane. It closes from the side and helps lubricate the eye and reduce the frequency of blinking. If one eye becomes dry, your cat may casually blink only one eye in order to moisturize it.