Cat squiting one eye

My Cat Is Squinting One Eye

Ever wondered why your cat is squinting one eye? Squinting or keeping the eye partially closed is one of the more easily noticeable signs that there is something wrong with the eye. Even a busy cat owner can easily spot this abnormality with just a cursory glance at their pet. What causes and conditions are likely when a cat is squinting one eye? There are many reasons for this. Let us first familiarize ourselves with what is normal. The eyes of healthy cat are clear and bright with no discharges. The conjunctiva is the membranous tissue lining the eyelids including the third eyelid and part of the eyeball. In health, the conjunctiva is moist and pale pink. A cat’s third eyelid must not be visible when the cat is awake and alert.
cat eye structure squinting

Structures associated with the cat’s eye. The conjunctiva is the mucous membrane lining the eyelids and part of the eyeball. We usually call the nictitating membrane the third eyelid.

Observable signs indicating that something is not right with the eyes are the following: Redness and swelling of the conjunctiva and excessive tear production. You may observe the fluid discharges from the eye, ranging from watery to thick and pus-like. The third eyelid partially covers the eyes. There is cloudiness and sometimes a film of mucous may form over the eyes. The cat may become sensitive to light and blink constantly.  The cat may keep the affected eye partially or fully closed, hence you noticing that your cat is squinting one eye.
Cat Is Squinting One Eye

When the third eyelid covers the eyes partially, this is an indication that something is wrong with the eye. This may look like your cat is squinting one eye.

Cat Is Squinting One Eye… What Are the Causes?

Blepharitis and Conjunctivitis

This is the inflammation of the eyelids and the conjunctival membranes that line the eyelids, respectively.  In these conditions, the eyelids and the margins of the eyelids become swollen and the cat will look like it is squinting.
cat with swollen eye lid

In the condition called blepharitis, it is the eyelid that is swollen giving the appearance that the cat is squinting one eye.

Blepharitis and conjunctivitis may be caused by physical traumatic injury to the eyelids or conjunctiva. The pain from the injury will cause the cat to close its eyes or squint. Trauma may be due to a scratch, an abrasion or a laceration. Certain chemical substances, pellets from BB guns and small pieces of shattered glass are also common items causing trauma to the eyes and its associated structures. Allergies, especially a generalized systemic allergic reaction from inhalant and food allergens, can cause the eyelids and conjunctiva to become reddened and swollen. Localized allergic reaction, example from insect bites, can also cause swelling of the eyelids and squinting. Foreign bodies that irritate the eyelids and conjunctiva can also cause squinting of the affected eye. The most common of this is the condition called entropion, a congenital anomaly of the eyelid. In this condition, the edges of the eyelids are turned inwards and the eyelashes rub against the cornea. Infections can also cause swelling of the eyelids and conjunctiva. We will consider upper respiratory diseases below. Bacterial infection, usually due to Staphylococcus, cause abscess of the glands of eyelids or a general infection of the eyelids. A stye is a red lump seen near the edge of the eyelid caused by an infection of the sebaceous glands of the eyelid.  A generalized dermatitis can extend to the eyelids and cause swelling and squinting.

Blepharospasm

This is defined as the involuntary closure of the eyelids, hence squinting. The condition usually starts with rapid eye blinking and later the eyelids will close. It is a sign that something is wrong with the eye or eyelid — usually an infection or injury, much the same as those already mentioned above. Painful conditions affect the free nerve endings in the cornea and conjunctival membranes and cause blepharospasm.
cat with blepharospasm

Blepharospasm is the involuntary closure of the eyelids usually caused by painful conditions which affects the free nerve endings.

Symblepharon

This is the adhesion of conjunctival tissue to another conjunctival surface or to the cornea usually seen in feline herpesvirus infection especially in kittens 10 days to 3 weeks old. The eyes are almost glued together by the discharge making it look like the kitten is squinting the affected eye.
Cat with eye discharge

In symblepharon, the excessive eye discharges almost glue together the eyelids. This is commonly seen in kittens with feline herpesvirus infection.

Infections of the Upper Respiratory Tract

We generally call this group of diseases Influenza, Cat Flu, or Viral Rhinitis. Viral upper respiratory tract diseases are self-limiting but bacteria, like Bordetella bronchiseptica, Chlamydophila felis and Mycoplasma, can complicate them and result in a more serious disease.
cat with conjunctivitis

Infectious diseases of the upper respiratory tract caused by viruses and bacteria cause conjunctivitis.

Feline Viral Rhinotracheitis is caused by feline herpesvirus I which attacks the conjunctiva causing swelling of eyelids. There is discharge from the eyes, first watery and later becomes pus-like. After the cat recovers, the virus “hides” in the tissues and flare-ups can occur when the cat experiences stress. Feline Calicivirus infection has the same general symptoms as feline herpesvirus infection — conjunctivitis, eye discharges and blepharospasm or squinting. Even cats that have recovered from calicivirus infection can get reinfected with other strains. Feline pneumonitis is a disease that Chlamydophila felis causes. The symptoms also include inflamed eyes which become red and bloodshot. There are also discharges from the eyes. This disease causes a more serious conjunctivitis than the viral ones.

Keratoconjunctivitis sicca

This is the chronic inflammation of the cornea and surrounding conjunctival tissues due to being constantly dry because of decreased tear production. Tears are necessary to remove debris and infectious agents from the eye. When there is little or no tear formation, eye irritation is constant and the cat will squint. Keratoconjunctivitis sicca commonly arrives due to immune-mediated damage to the tear-producing glands or herpes virus infection.

Anisocoria

This is a condition wherein the pupils of the cat’s eyes are not of the same size. This may indicate corneal injury, the central nervous system (CNS) or peripheral nerve problems, glaucoma, or inflammation in the interior of the eye. The eyelid of affected eye is droopy and the cat is often squinting or rubbing the eye.
cat squinting one eye

In anisocoria the pupils are not of the same size, the eyelid of the affected eye is often droopy, hence the cat is squinting one eye.

Other Conditions

Any eye condition that causes sensitivity to light or photophobia can result in squinting. Diseases affecting some of the cranial nerves may result in facial paralysis causing droopy eyelids which appears like squinting.  

What To Do When the Cat Is Squinting One Eye

The eye is a very delicate organ. Only a trained veterinarian can perform a thorough physical examination of the eyes. When you see that your cat is squinting one eye, or even both eyes, it is best to make an appointment for a veterinary office visit immediately. The problem must be diagnosed properly at the soonest possible time and treatment started early. Simple conditions like a shallow scratch on the cornea can get infected and complicated. Eye problems left unresolved for a prolonged period of time may result in permanent eye damage and blindness. Viral respiratory infections may complicate to pneumonia. Do not force the eyelids open on your own because you may only aggravate the injury. Sometimes he may need a sedative or pain reliever first, especially in cases of traumatic injury. Do not attempt to give pain relievers orally at home using over-the-counter human pain medicines because they may be toxic and fatal to cats.

Home Care

At home, the first thing to do is to prevent further self-trauma to the irritated eye by putting an Elizabeth collar on your cat. Keep the cat comfortable by turning down bright lights or place the cat in a dimly lit room. Apart from obvious traumatic injuries, it is better to assume that whatever is causing the inflammation of the eyes may be contagious. Therefore isolate the cat from other cats in a multi-cat household. Proper home care is essential to keep the cat comfortable and less likely to keep trying to scratch the irritated eye. Gently wipe away eye discharges with a warm damp cloth. Start wiping from the corner near the nose working outwards to move debris away from the eyes. When the eyes are cleared of dried up discharges, you may place over it a sterile pad soaked in cold water to help soothe the irritation. In case of chemical irritants, you may flush the eyes with artificial tears. Do not use tweezers on the eyes. If you need to remove a foreign object from the eye, you may use a cotton swab and do it gently. Nursing care at home is important especially feeding. A cat that is sick will not have an appetite to eat but must have nourishment so that the immune system can fight back infections. Your veterinarian can give you advice on home-feeding sick felines.

Prevention of Eye Problems

Vaccination is of prime importance to protect your cat against the respiratory viruses – feline herpesvirus and feline calicivirus.
cat vaccination

Have your cat vaccinated to protect them against the common viral causes of upper respiratory diseases?

To prevent traumatic injuries to the eyes, do not leave objects with sharp edges lying around which the cat might see as a toy. Put away in a safe place, objects like needles. Make sure you close the lids of trash cans tightly. Proper nutrition will keep the cat’s immune system strong to fight off infections. Regular grooming of cats with bulging eyes or long hair can help prevent eye irritation. Cats are hardy, independent creatures. When something is bothering a cat, they are more likely to hide than seek human attention. So cat owners must take some time to give their pets a regular “nose to tail” check. Early intervention can go a long way in the management of diseases affecting a fragile yet very important organ such as the eye. If you are concerned about your cat’s wellbeing, then you may want to check out another health-related article here.  

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