Cat Closing One Eye: Why Does My Cat Keep Closing One Eye?

When your cat is consistently closing one eye, it can be a cause for concern for any pet parent. The most common reasons a cat keeps closing one eye include irritation, infection, injury, or foreign objects in the eye. While a single, brief blink or a slow wink can be a sign of affection, persistent closing, squinting, or a droopy eyelid usually indicates something more. This comprehensive guide will delve into the various causes, symptoms, and potential treatments when your feline friend seems to be favoring one eye.

Feline Ocular Health: A Delicate Balance

A cat’s eyes are incredibly expressive and vital for their interaction with the world. They are sensitive organs, and any deviation from normal functioning warrants attention. When you notice your cat blinking one eye more than usual, or if they appear to be cat squinting one eye, it’s your cat’s way of communicating discomfort or pain. Ignoring these signs could lead to more severe issues, affecting your cat’s vision and overall well-being.

Deciphering the Signs: What to Look For

Beyond the simple act of closing one eye, several other visual cues can help pinpoint the problem. Observing these symptoms will be crucial when consulting your veterinarian.

Cat Eye Discharge: The presence of discharge from one or both eyes is a common indicator of an underlying issue. This discharge can vary in appearance:
- Clear and watery: May suggest allergies, irritants, or early-stage viral infections.
- Thick, yellow, or green: Often points to a bacterial infection.
- Crusty or sticky: Can be a sign of dried discharge, common with infections or inflammation.
Cat Watery Eye (Epiphora): Excessive tearing from one eye can be a response to irritation, a blocked tear duct, or even pain. The tears may be clear but can sometimes become cloudy if an infection sets in.
Cat Droopy Eyelid (Ptosis): If one of your cat’s eyelids appears to be hanging lower than usual, it could be due to swelling, nerve damage, or an eye injury. This can obstruct vision and cause the cat to close the eye more often.
Redness and Swelling: Inflammation of the conjunctiva (the membrane lining the eyelid and covering the white part of the eye) often results in a pink or red appearance. Swelling of the eyelids can also occur.
Cloudiness or Discoloration: A cloudy appearance in the pupil or iris can indicate more serious conditions like cataracts, glaucoma, or corneal damage.
Rubbing or Pawing at the Eye: If your cat is frequently rubbing their face against furniture or pawing at their affected eye, they are trying to relieve discomfort or remove an irritant.
Sensitivity to Light (Photophobia): Your cat might seek out dark places or squint excessively when exposed to bright light.

Common Causes of One-Eyed Closing

Several conditions can lead to your cat closing one eye. Let’s explore the most frequent culprits:

1. Cat Conjunctivitis (Pink Eye)

Conjunctivitis is inflammation of the conjunctiva, the thin membrane covering the inside of the eyelids and the front of the eyeball. This is a very common reason for a cat blinking one eye.

Causes:
- Viral Infections: Feline herpesvirus (FHV-1) and feline calicivirus are frequent offenders. These can cause upper respiratory infections that also affect the eyes.
- Bacterial Infections: Chlamydophila felis and Mycoplasma are common bacterial causes.
- Allergies: Environmental allergens like pollen, dust, or even certain foods can trigger allergic conjunctivitis.
- Irritants: Smoke, dust, strong perfumes, or chemicals can irritate the conjunctiva.
- Foreign Bodies: A tiny speck of dust or a grass seed can lodge in the eye, causing inflammation.
Symptoms: Redness, swelling of the conjunctiva, cat eye discharge (clear, watery, or sometimes pus-like), squinting, and increased blinking.
Treatment: Treatment depends on the cause. Antibiotic eye drops or ointments are prescribed for bacterial infections. Antiviral medications might be used for severe viral cases. Antihistamines or corticosteroid eye drops can help with allergies, but these are used cautiously by veterinarians. Keeping the eye clean by gently wiping away discharge with a warm, damp cloth is also important.

2. Feline Eye Infection (Beyond Conjunctivitis)

While conjunctivitis is a specific type of infection, other parts of the eye can also become infected, leading to your cat closing one eye.

Keratitis: This is inflammation of the cornea, the clear outer layer of the eye. It can be caused by viruses, bacteria, fungi, or trauma. Symptoms include pain, redness, cloudiness of the cornea, and the cat holding the eye closed.
Uveitis: This is inflammation of the uvea, the middle layer of the eye that contains blood vessels. Uveitis can be caused by infections, trauma, autoimmune diseases, or cancer. Signs include redness, pain, pupil constriction, and a hazy appearance to the eye.
Treatment: A veterinarian will diagnose the specific type of infection and prescribe appropriate medications, which might include antibiotics, antifungals, or anti-inflammatory drugs.

3. Cat Stye (Hordeolum)

A stye is a painful, localized swelling on the edge of the eyelid, usually caused by a bacterial infection in an oil gland or hair follicle.

Symptoms: A red, painful lump on the eyelid margin, similar to a small pimple. The cat may squint or hold the eye closed due to discomfort. There might be some cat eye discharge.
Treatment: Warm compresses applied gently several times a day can help the stye drain naturally. In some cases, a veterinarian may prescribe antibiotic ointments. It’s crucial not to try to pop or squeeze a stye, as this can spread the infection.

4. Cat Corneal Ulcer

A corneal ulcer is a scratch or abrasion on the surface of the cornea. This is a painful condition that often results in the cat holding the eye tightly shut to protect it.

Causes:
- Trauma: Scratches from other cats’ claws, rough play, or contact with foreign objects.
- Irritation: Persistent rubbing due to allergies or inflammation.
- Dry Eye (Keratoconjunctivitis Sicca): Insufficient tear production can lead to a dry cornea, making it prone to damage.
- Infections: Certain viruses or bacteria can directly damage the cornea.
Symptoms: Severe pain, cat squinting one eye, excessive tearing, redness of the eye, and sometimes a cloudy or opaque appearance to the cornea. You might notice your cat pawing at the eye.
Treatment: This requires prompt veterinary attention. Treatment typically involves antibiotic eye drops to prevent secondary bacterial infection, pain medication, and sometimes anti-inflammatory drops. In severe cases, surgery might be needed to help the ulcer heal. The cat will likely need an Elizabethan collar (cone) to prevent further self-injury.

5. Foreign Bodies in the Eye

As mentioned earlier, even a tiny speck of dust, a grain of sand, a small insect, or a piece of plant material can get lodged in your cat’s eye.

Symptoms: Sudden onset of cat blinking one eye, excessive tearing, pawing at the eye, redness, and visible discomfort.
Treatment: If the foreign body is visible and easily accessible, you might be able to rinse it out with sterile saline solution designed for eye use. However, if the object is embedded or you cannot remove it easily, seek veterinary help immediately. Attempting to remove it forcefully can cause further damage, potentially leading to a cat corneal ulcer.

6. Dry Eye (Keratoconjunctivitis Sicca)

Dry eye occurs when the tear glands don’t produce enough tears to keep the eye adequately lubricated. This can lead to irritation, inflammation, and even corneal ulcers.

Symptoms: Chronic dry, dull appearance of the eye, stringy discharge, redness, squinting, and increased blinking. Over time, the cornea can develop pigmentation or scarring.
Treatment: This is a lifelong condition for affected cats. Treatment involves using artificial tear solutions and medications like cyclosporine or tacrolimus, which stimulate tear production. Regular monitoring by a veterinarian is essential.

7. Allergies

Cats, just like humans, can suffer from allergies. These can manifest as skin issues, respiratory problems, or eye irritation.

Symptoms: If allergies are the cause, you might see cat watery eye, redness, itching, and possibly sneezing or a runny nose. The cat might also groom excessively in other areas.
Treatment: Identifying and removing the allergen is the first step. This can be challenging. Veterinary diagnosis might involve elimination diets or skin testing. Treatments can include antihistamines, corticosteroid eye drops (used judiciously), or immunotherapy.

8. Entropion and Ectropion

These are eyelid abnormalities where the eyelid rolls inward (entropion) or outward (ectropion).

Entropion: When the eyelid rolls inward, the eyelashes and fur can rub against the cornea, causing significant irritation, pain, and leading to a cat squinting one eye and potential corneal ulcers.
Ectropion: The outward rolling of the eyelid can leave the eye exposed and prone to dryness and infection.
Treatment: Surgical correction is usually required to reposition the eyelid correctly and prevent further damage to the eye.

9. Glaucoma

Glaucoma is a condition characterized by increased pressure inside the eye. This pressure can damage the optic nerve and lead to blindness if left untreated.

Symptoms: While not always obvious, signs can include redness, cloudiness of the cornea, dilated pupil, pain (your cat may be less active or reluctant to be handled), and the cat holding the affected eye partially or fully closed.
Treatment: Glaucoma requires immediate veterinary intervention. Treatment aims to reduce eye pressure, often with specific eye drops. In some cases, surgery or even enucleation (removal of the eye) may be necessary to manage the pain and pressure.

10. Injury or Trauma

A direct injury to the eye, such as a scratch from another animal, a blow to the head, or even getting a foreign object embedded deep within the eye socket, can cause a cat to close one eye.

Symptoms: Vary depending on the injury but can include pain, swelling, bleeding, a visible wound on the eye or eyelid, and the cat holding the eye shut. A cat droopy eyelid can also be a result of trauma.
Treatment: Immediate veterinary care is essential. Treatment will depend on the severity and nature of the injury and may involve surgery, medications, or specialized eye care.

When to See the Veterinarian

It’s crucial to seek veterinary advice if you notice any of the following:

Persistent closing or squinting of one eye.
Any noticeable change in the eye’s appearance (cloudiness, redness, swelling).
Presence of discharge, especially if it’s thick, yellow, or green.
Your cat is pawing excessively at their eye.
Signs of pain or distress (meowing, hiding, lethargy).
Any suspicion of an injury.

A veterinarian can perform a thorough eye examination, which may include:

Visual inspection: To look for redness, swelling, discharge, and foreign bodies.
Schirmer Tear Test: To measure tear production.
Fluorescein Dye Test: To detect corneal ulcers or abrasions.
Tonometry: To measure intraocular pressure (to check for glaucoma).
Slit Lamp Examination: To get a magnified view of the eye’s structures.
Cytology or Culture: To identify the type of infection if present.

Home Care and Prevention

While veterinary care is paramount for diagnosing and treating eye issues, there are some things you can do at home and to prevent future problems:

Gentle Cleaning: If there is mild discharge, you can gently clean the area around your cat’s eye with a soft, damp cloth soaked in warm water. Use a separate cloth or a different section of the cloth for each eye to avoid spreading infection. Never use cotton swabs directly in the eye.
Preventative Care:
- Keep your cat indoors or supervise them closely outdoors to minimize exposure to hazards like fights with other animals or thorny plants.
- Maintain a clean living environment to reduce dust and allergens.
- Provide a balanced diet to support overall health and immune function.
- Regular grooming can help keep fur out of the eyes.
- Annual veterinary check-ups are essential for early detection of any health issues.
Administer Medications as Directed: If your veterinarian prescribes eye drops or ointments, ensure you administer them precisely as instructed, even if the symptoms seem to improve. Stopping medication too early can lead to a relapse.

Summary Table of Causes and Symptoms

Cause of Closing One Eye	Key Symptoms
Cat Conjunctivitis	Redness, swelling, clear or pus-like discharge, increased blinking.
Feline Eye Infection (General)	Pain, redness, discharge, cloudy appearance, squinting.
Cat Stye	Painful lump on eyelid, redness, possible discharge, squinting.
Cat Corneal Ulcer	Severe pain, intense squinting, excessive tearing, corneal cloudiness.
Foreign Body	Sudden discomfort, excessive tearing, pawing at eye, redness.
Dry Eye (Keratoconjunctivitis Sicca)	Dry eye appearance, stringy discharge, redness, squinting, dullness.
Allergies	Watery eye, redness, itching, possible sneezing.
Entropion/Ectropion	Eyelid abnormality, irritation, discharge, squinting.
Glaucoma	Redness, corneal cloudiness, dilated pupil, pain, eye held closed.
Injury/Trauma	Pain, swelling, bleeding, visible wound, eye held closed, possible droopy eyelid.

Frequently Asked Questions (FAQ)

Q1: Can I treat my cat’s eye problem at home without a vet?
A1: While gentle cleaning of the eye area can be done at home, it is strongly advised against treating any significant eye issue without veterinary consultation. Misdiagnosis or improper treatment can worsen the condition, lead to permanent vision loss, or cause severe pain for your cat.

Q2: How can I tell if my cat’s eye problem is serious?
A2: If your cat is cat squinting one eye persistently, if there is any change in the eye’s color or clarity, if there’s abnormal discharge (especially colored pus), or if your cat shows signs of pain or distress, the problem is likely serious and requires immediate veterinary attention.

Q3: My cat’s eye is watery, is that normal?
A3: A small amount of clear tear production can be normal, especially in certain breeds or if there’s a minor irritant. However, excessive tearing (cat watery eye) that persists, is accompanied by redness, discharge, or squinting, indicates an underlying problem that needs veterinary evaluation.

Q4: What if my cat has a droopy eyelid?
A4: A cat droopy eyelid can be a symptom of various issues, including nerve damage, swelling, or injury. It’s essential to have this examined by a veterinarian to determine the cause and appropriate treatment.

Q5: How do I administer eye drops to my cat?
A5: Gently hold your cat’s head and use one hand to gently pull down their lower eyelid to create a pocket. With the other hand, hold the eye drop bottle above the eye (without touching the eye) and squeeze the prescribed number of drops into the pocket. Be careful not to let the dropper tip touch the eye or eyelid. Many cats resist, so having a second person to help hold your cat securely can be beneficial. Consult your vet for a demonstration if you’re unsure.

By being observant of your cat’s eye health and acting promptly when you notice changes, you can ensure your beloved feline companion maintains clear, comfortable vision for years to come.