Conjunctivitis in Cats

Picture of a Maine Coon Cat

Cats can have a variety of eye problems, but conjunctivitis is by far one of the most common ones that affect our feline friends. In this post, we’ll look at its symptoms, how it is diagnosed, how it is treated, and when you should expect your cat to recover from this health issue.

What Is Cat Conjunctivitis?

Feline conjunctivitis can be defined as the inflammation of the conjunctiva. But what is the conjunctiva? Both in humans and in animals, the eye is formed of several different layers. The conjunctiva is a membrane that can be found on the inside of the eyelids.

The membrane plays the part of protecting the cat’s eye from dirt and debris, as well as potential pathogens. Instead of your cat developing a severe eye infection, he or she will first develop conjunctivitis, which can be easier to treat compared to other eye problems.

The inflammation can show up in one eye or both, but most cats usually transmit the germ that has caused it to the other eye, too, during their grooming process.

Causes of Conjunctivitis in Cats

Feline conjunctivitis can be infectious and non-infectious. The infectious type can be caused by bacteria and viruses. Out of the first, Chlamydophila is the most common bacteria to cause conjunctivitis, along with a respiratory infection that affects the animal’s upper tract. The cat usually sneezes and has watery or red eyes.

Feline herpesvirus is very contagious, so it can easily be passed on from one cat to another, especially if they use the same food and water bowls, the same litter box, and they come in close contact every day.

Non-infectious conjunctivitis can be caused by irritants such as dust and debris, which will mechanically cause the inflammation of the conjunctiva. However, once this happens, the membrane becomes vulnerable to infections, so allergic conjunctivitis can lead to infectious conjunctivitis as time goes by.


Most cats that have conjunctivitis will express tearing or watering from one or both of their eyes. Some will have an unusually colored discharge (green, yellow, or cloudy). Others have red or swollen conjunctiva, which will cause them to squint or paw at their eyes. Depending on the level of pain and discomfort they feel, many cats will try to ‘solve’ the problem by excessively cleaning their eye regions. This can lead to further bacterial or viral complications.

If you notice any of the clinical signs that we have mentioned in your feline buddy, it’s time to take him or her to the veterinary clinic for a checkup and a diagnosis.


Once you get to the vet, they will ask you several questions to determine what might have caused the condition. You should provide detailed info about the exact moment you have noticed the issue, if your cat was in contact with other cats, whether indoors or outdoors, if he/she is vaccinated according to the schedule, and if there are any other changes on the cat’s health status besides the eye problem.

The veterinarian will then examine your cat’s eyes and look for potential foreign bodies that might have gotten lodged under the eyelids.

Additional testing is necessary if a case of infectious conjunctivitis is suspected, especially since it can be caused by viruses, but also by many bacteria such as Streptococci and Staphylococci, or Mycoplasma. Since the results of the tests might be available in several days’ time, the cat will receive symptomatic treatment for the time being.

In some cases, conjunctivitis can be a sign of eye cancer, and if this disease is suspected, several other tests will have to be performed.


The vast majority of bacterial conjunctivitis cases are resolved in under 14 days, so long as the animal gets the correct antibacterial treatment. That is why the tests and antibiogram are so important, so that your feline friend can receive specific medication for the exact pathogen that has caused the health problem.

For example, if the conjunctivitis was caused by Mycoplasma or Chlamydophila, the cat will receive treatment with Azithromycin (orally) and you might have to administer a Tetracycline ointment at home.

Allergic conjunctivitis can be treated using corticosteroid drops or ointments, as well as topical medications that are capable of decreasing the allergic reaction.

Make sure to use only the medications that your veterinarian has prescribed. Not all of the antibiotic ointments out there are made for eye application, and they might make matters worse, such as irritate the cat’s eyes even more.

Administering Eye Medication in Cats

Putting eye drops into your cat’s eyes can be a challenge that no pet parent is looking forward to. However, it can be necessary, especially during the first few days of the treatment. In some cases, you might have to go through the process as many as six times a day, but most ophthalmic solutions have to be administered 2-3 times a day.

An ophthalmic ointment is by far easier to work with in this respect, as you will merely have to place a small quantity of the product on one or both corners of the eyes and then massage your cat’s eye so that the ointment is smeared across the eyeball.

Take your cat in for a checkup once you have completed the treatment. One important note that we must make is that you should always administer the medication until the end of the therapy period. Otherwise, the germ that might have caused the conjunctivitis case could become resistant to the antibiotic, and that would mean that you’d have to start all over with a different medication.

Preventing Conjunctivitis in Cats

There are a few simple steps that you can take to ensure that your cat doesn’t develop this eye problem. Keeping your house dust-free and using pet-friendly cleaners is a method, especially if your cat has been previously diagnosed with allergic conjunctivitis.

Since some breeds are more prone to developing conjunctivitis than others, such as Persians, for instance, using a mild eye cleaner on a regular basis can help you keep your cat’s eye health in check.

Make sure that your cat is vaccinated and take your feline companion to the vet at least 1 to 2 times a year for regular checkups.



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