Quick answer: Why is my cat’s eye red? A red eye is often linked to irritation or inflammation of the tissues around the eye, such as conjunctivitis, but it can also come from an infection, an eyelid problem or an irritant. Because eye problems can get worse quickly, a veterinarian should check a red eye. To organize what you are seeing, you can start with our Pet Symptom Checker, which covers cats and dogs.
What a Red Eye Can Look Like
Look closely at both eyes. Is one eye red or both? Is there discharge, squinting, swelling or a third eyelid showing? VCA Animal Hospitals describes conjunctivitis in cats as inflammation of the membrane that lines the eyelids and covers the front of the eye, which often makes the eye look red and irritated and may come with discharge.
When to Call the Vet Right Away
Before any home care, know what should not wait. VCA’s guidance on recognizing signs of illness in cats lists eye abnormalities among the signs that need prompt attention, and VCA’s conjunctivitis page says a cat with eye signs should be examined by a veterinarian. Call right away if your cat:
- keeps the eye closed, squints or paws at the eye;
- has a cloudy eye, a change in the color of the eye or a visible injury (cloudiness can signal a serious eye problem);
- has thick yellow or green discharge or a swollen eyelid;
- is also not eating, hiding or acting very tired (see not eating and hiding);
- is a kitten, a senior cat or has other health problems.
Possible Causes
Only a veterinarian can find the cause. According to VCA, conjunctivitis in cats can be caused by:
- Infections: feline herpesvirus and calicivirus are common, and bacteria such as Chlamydophila and Mycoplasma can also be involved.
- Eyelid problems, such as entropion, in which the eyelid rolls inward.
- Irritants, such as dust, smoke or other substances that reach the eye.
Other eye problems, such as inflammation inside the eye, can also make an eye look red. VCA’s page on uveitis in cats explains that it can be painful and, if untreated, may lead to glaucoma or blindness. This is why a red eye should not be treated at home without an exam.
What You Can Do While You Arrange Care
- Do not put any drops, ointment or human eye product in the eye unless your vet tells you to.
- Keep your cat from rubbing the eye. Ask your vet about a protective collar if needed.
- Keep the area clean and calm, away from smoke, dust and sprays.
- Take a clear photo of the eye and write down when it started.
- Separate cats if one has signs that may be infectious.
What the Veterinarian May Do
Your veterinarian will examine the eye and decide on tests and treatment based on the cause. Treatment may include prescription eye medication or treatment for an underlying infection. Always follow the instructions you are given.
How the Pet Symptom Checker Can Help
Our Pet Symptom Checker helps you look up symptoms in cats and dogs and see common reasons and warning signs. It does not diagnose and does not replace a veterinarian, but it can help you describe the problem clearly. For dogs, read why a dog’s eye is red, and learn the value of regular vet check-ups.
Frequently Asked Questions
Is a red eye in a cat an emergency?
Not always, but eyes can change fast. If your cat squints, has discharge or the eye looks cloudy, call your vet the same day.
Can I use human eye drops?
No. Some products can harm the eye. Use only what your vet prescribes.
Is cat conjunctivitis contagious?
It can be when it is caused by an infection. Ask your vet how to protect other cats at home.
Why is only one eye red?
One red eye can be an irritant, an injury or an eye problem. A vet exam is the safest way to know.
Final Thoughts
A red eye is a sign to take seriously. Keep your cat calm, avoid home treatments and call your veterinarian.
This article is for general education only. It does not diagnose any condition and does not replace advice from your veterinarian.
Sidnir Vieira is the founder of TechHavela. A lifelong pet owner who had a dog for many years and now lives with a cat, he writes educational guides that help owners understand symptoms and know when to call the vet. TechHavela’s articles are based on veterinary sources and are not reviewed by a veterinarian.
