Red Eyes in Cats: Common Causes and When To Call Your Vet

Red eyes in cats are usually a sign of irritation, injury, or an underlying eye condition—some mild, but others serious and vision-threatening.  

If your cat’s eye looks red, swollen, or is producing discharge, it’s important to monitor closely and contact your veterinarian, especially if symptoms persist or worsen.

Common causes of red eye sin cats include infections, allergies, trauma, and underlying conditions like conjunctivitis or glaucoma.  

Because eye problems in cats can progress quickly, early evaluation and treatment are key to protecting your pet’s comfort and vision. 

Causes of Red Eyes in Cats

Many conditions can affect cats’ eyes, some of which concern the eye itself (called the globe) and others that affect the tissue surrounding the eye. Problems affecting the globe are usually more serious than those affecting the tissue. 

The most common causes of red eyes in cats include: 

• Conjunctivitis  

• Injury/trauma (such as corneal ulcers) 

• Allergies 

• Glaucoma  

• Household irritants like perfumes and candles 

• Hyphema 

• Infections 

What To Do If Your Cat’s Eyes Are Red

If your cat’s eyes are red, have them examined by a veterinarian. Don’t let a potentially serious eye problem go undiagnosed.  

Cats with significant redness, swelling, or discharge from the eye—and those that are unable to open their eyes or squinting heavily—should be seen immediately on an emergency basis, as should cats that aren’t feeling well and have changes in their eyes. 

If your cat can open their eyes, they seem to be feeling fine otherwise, and the signs are mild, the problem can likely wait up to 24 to 48 hours for an appointment.  

If you aren’t sure when to come in, call your vet to ask their advice. 

How Veterinarians Diagnose Red Eyes in Cats

To diagnose the underlying cause of red eyes in cats, your veterinarian will go over your cat’s medical history. Then they’ll conduct a physical exam and a fluorescein stain test. During this test, a small amount of dye is placed on the surface of the eye to look for scratches or injuries to the cornea.

Other tests may be recommended. These include: 

• A tonometry test (this measures the pressures in the eye) 

• A Schirmer tear test (looking at how well tears are being produced) 

• Blood work 

• X-rays 

Treatment of Red Eyes in Cats

Treatment of red eyes in cats will depend on the underlying issue.  

Many cases of red eye are treated by first removing the discharge in the eye—which can often be done carefully with a moistened gauze—and keeping the face clean.  

Then, appropriate medications will be recommended. 

Drops or ointments, which may contain anti-inflammatory as well as anti-infectious medications, are used for most cases of conjunctivitis. 

Injuries must also be carefully treated to ensure that infection doesn’t occur while medication to treat pain and inflammation is applied.

Some cats may also benefit from oral medications, but for most pets, topical treatment is preferred. 

Within a week, your cat’s eye inflammation should be reduced or gone with appropriate diagnosis and treatment. 

Prevention of Red Eyes in Cats

Preventing red eyes in cats can involve several steps, including: 

• Keep up with annual wellness exams with your vet 

• Ensure your pets are properly trained and get along to avoid accidental injury 

• Keep all your pets’ nails short and dull 

• Minimize dust and smoke exposure 

• Use pet-safe cleaning products 

• Ensure adequate ventilation 

• Avoid exposure to aerosols