Cat looks out window

Key takeaway

Redness in your cat’s eyes can be a sign of inflammation. Red eyes in cats may stem from trauma, illness, infection, and obstruction. To treat red eyes, a veterinarian should diagnose the root cause and prescribe treatment, often through medication. 

Pet illnesses can be frustrating because your cat can't simply tell you what's wrong - at least in words. As a cat owner, it’s important to be on the lookout for signs of illness, and red eyes in cats is one such symptom.

Red eyes indicate inflammation, so it’s important to determine the root cause to properly treat your furry friend. If you see your cat presenting with red eyes, even if nothing else appears to be wrong, take your cat to the vet.

Common Causes of Red Eyes in Cats

There's a range of conditions that could make your cat's eyes turn red, from simple irritation to infection to autoimmune disease. Here are some of the most common causes of red eyes in cats:

Infections

The number one reason why you don't want to ignore red eyes in cats is that the inflammation could be caused by an infection, and infections are always at risk of becoming much worse. The infection can be bacterial or viral, and these need to be treated and monitored as soon as possible.

Bacterial 

On the bacterial side, infections from the pathogen that causes chlamydia is very common in cats. The chlamydia that infects cats, Chlamydia felis, is not the same as the sexually transmitted disease that humans can contract, but it's possible for a cat to transmit the feline bacteria to humans. In cats, chlamydia is mainly an upper respiratory condition that can also affect the cat's eyes, making them develop chlamydial conjunctivitis. The conjunctiva of the eyes turns red and becomes inflamed when infected, and a greenish or yellowish discharge is present.

It takes a week and a half or less for the infection to take hold after your cat has been exposed to an infected cat. A vet needs to do a lab test to diagnose the condition. If you have more than one cat, have each cat treated as if it were infected, too, even if it isn't showing symptoms yet.

Feline hypertrophic mycoplasmosis (FHM) is another bacterial infection, although this one isn't as common. This affects the cat's red blood cells and can lead to anemia if enough red blood cells are destroyed. Eventually the conjunctiva of the eyes can turn yellow or white, and there may be discharge, which itself could irritate the cat's eyes. However, it's also possible for the cat to be infected and not show any symptoms at all.

In both cases, antibiotics are the answer. Chlamydia can be treated rather easily most of the time, but FHM can be more difficult to get rid of.

closeup of cat’s eyes

Viral

Viral infections include Feline Herpesvirus, calicivirus, feline immunodeficiency virus (FIV), and feline leukemia (FeLV). Herpesvirus and calicivirus can lead to corneal  ulcers and ultimately destroy the eye.e  FIV and FeLV can result in conjunctivitis because of viral irritation and a compromised immune system.

Treatments for these viruses are not always successful, and it's better to focus on management of symptoms, making the cat comfortable, and preventing the spread of the viruses.

Trauma

Trauma or injury can also result in conjunctivitis . Cats can not only get into fights, but they can mistakenly hit each other too hard while roughhousing. Cats can also have clumsy accidents that lead to scratches and sores on the eye or eyelid. They can also suffer bites, and, of course, lacerating trauma will lead to red eyes.

With trauma, the problem is two-fold. One, you have to prevent the laceration from becoming infected, and two, you have to try to help the cat heal so that its vision is unaffected. If you notice that your cat has some sort of eye injury, bring it to the vet as soon as you can.

Allergens

Pollen and dust are both very common allergens for cats, and just as these too can lead to red eyes in humans, so too can they make your cat's eyes turn that bright, alarming color.

Mitigating the effect of cat allergies is almost the same as treating human allergies to pollen and dust: Vacuum, wash everything, dust everything to pick up loose dust and pollen grains, run an air filter or the air conditioner, and so on. Your vet can give the cat antihistamines or corticosteroids as needed. Do not try to administer human antihistamines or other medicines to your cat; always consult with a professional first.

Obstructions and Foreign Matter

Cats can get dirt, grass, pebbles, and other foreign matter stuck in their eyes. Have you ever suddenly felt something in your eye, and you know not to rub your eyes then because that could lead to corneal damage? It's essentially the same with cats. Something gets stuck in their eyes and scratches up the cornea or leads to irritation of the surrounding tissues.

Chronic Diseases

Cats, like other animals, are at risk for developing cancer and autoimmune issues. Different cancers can affect the animal's eyes, especially feline lymphosarcoma-leukemia complex. Autoimmune disorders can lead to a condition called uveitis, which has eye inflammation as a symptom.

Eye Growth or Structural Changes

If your cats eyes are red, your veterinarian may also want to look at congenital issues such as distichiasis, in which eyelashes grow from spots that are not where those lashes would usually grow; in other words, instead of the lashes growing from the regular line of follicles, they might grow from a nearby spot. This results in the lashes growing too close to the eyeball and potentially irritating it. Two other eyelash conditions are entropion and ectropion, in which the lid itself sticks inward or outward. Surgery is usually required to fix these types of conditions.

Because the potential number of causes that could result in a cat with red eyes is so large, you must see your veterinarian for a full exam and consultation.

Treating Red Eyes in Cats

Any effective treatment has to target the primary cause. If your cat is struggling with red eyes, proper diagnosis from a veterinarian is essential. If it's an allergy, then allergy medication and cleaning the areas the cat stays in are necessary. If it's a bacterial infection, antibiotics are needed. Is it a foreign object embedded in the eye? Surgery may be the way to go. And if it's cancer, chemotherapy is in order.

Only your veterinarian can prescribe proper treatment, so do not attempt home remedies until consulting with a professional. 

Veterinarian using eye drops on cat

My Cat Has Red Eyes: Frequently Asked Questions

What should I do if my cat's eye is red?

Take note of the symptoms: where the redness is in the eye, the color of any discharge, if your cat is sneezing, or if other signs of trauma are present, then contact your veterinarian immediately. If your cat has red eye problems, don’t wait for it to worsen.

Why is one of my cat's eyes red?

If your cat has one red eye, and the other is fine, you could be looking at an abrasion or object in the eye. You might also be seeing the result of something like a tumor. Again, there are many potential causes. However, things like allergies would, at least in theory, affect both eyes and not just one.

What does a cat eye infection look like?

A cat eye infection can present through an array of symptoms. The eyes may be mildly red or cloudy, they may be leaking discharge, or you may notice that your cat seems to be struggling to see. Anything that looks out of the ordinary is cause for concern.

Final Notes

Cats can be tough little creatures, but their eyes can be very vulnerable and may turn red due to infection, trauma, allergies, and more.

When you need cat care, Dutch provides veterinary telehealth consultations where you can get prescriptions delivered right to you. Whether you’re dealing with a cat ear infection or eye inflammation, we can help. Sign up online and we’ll connect you with a Dutch-affiliated vet within 24 hours.

Once you meet with a vet and describe your cat’s symptoms, they will provide a proper diagnosis and prescribe you the correct treatment. We make caring for your pet easy, so your cat can live their healthiest, happiest life.