If your cat’s eyes are looking red, swollen, or just a bit off, don’t brush it aside. It might be pink eye.
Yes, cats get it, too. Pink eye, or conjunctivitis, is one of the most common eye issues in cats. And it’s not just common. It’s really uncomfortable.
It affects a thin, see-through layer called the conjunctiva. This membrane covers the white part of the eye and performs a vital yet discreet function: keeping the eye moist and protecting it from harmful substances, such as dust, dirt, and germs.
In this guide, we’ll break down what causes conjunctivitis, how to spot it, and what treatments actually work. We’ll also share tips to help you protect your cat’s eyes going forward.
What Causes Conjunctivitis in Cats?
Conjunctivitis in cats can result from both infectious and non-infectious sources. Identifying the cause is key to successful treatment.
Infectious Causes
These are especially common in shelters and multi-cat households.
Viral Infections
Viruses are one of the most common reasons cats develop conjunctivitis. The usual suspects include:
Feline herpesvirus (FHV-1): Extremely contagious. It often flares up again when a cat is stressed.
Feline calicivirus (FCV): This virus doesn’t just affect the eyes. It also impacts the respiratory system.
Other viruses like FIP or FIV: They’re less common but still important. These viruses can weaken the immune system and make cats more susceptible to eye infections.
Bacterial Infections
Bacterial conjunctivitis often shows up after a viral infection, but it can also happen on its own. Here are the main ones to know:
Chlamydia felis: One of the top bacterial causes of pink eye in cats, especially in places where cats live close together, like shelters.
Mycoplasma spp.: These bacteria tend to cause milder eye issues. They might not come with as many respiratory signs as others.
Other bacteria that can lead to conjunctivitis include:
Staphylococcus
Streptococcus
Bartonella
Pseudomonas
Fungal Infections
Although rare, fungal infections may lead to conjunctivitis, especially in immunocompromised cats. These infections are usually environmental in origin. Pathogens include:
Aspergillus
Candida
Cryptococcus
Fungi thrive in soil, bird droppings, and decaying organic matter, making outdoor cats more susceptible.
Non-Infectious Causes
Not all pink eye comes from infection. Some cases aren’t contagious at all. Still, they can make your cat just as uncomfortable.
Allergies and Irritants
Cats can react and be allergic to everyday things, such as dust, smoke, pollen, and even scented litter. You might notice red eyes, squinting, or extra tearing. It’s their way of saying, “Something’s not right.”
Eye Trauma and Foreign Bodies
Scratches, bumps, and debris can directly inflame the eye’s delicate lining. Outdoor cats and those prone to fights are at higher risk. Even an eyelash or a grain of sand can trigger conjunctival inflammation.
Underlying Health Conditions
Sometimes, conjunctivitis isn’t the root issue. It’s just one sign of something more serious going on.
Autoimmune diseases: Rare, but they happen. Conditions like lupus or pemphigus can cause ongoing eye inflammation that’s tough to manage.
Dry Eye (Keratoconjunctivitis Sicca): If your cat doesn’t make enough tears, the eyes get dry and sore. You may notice thick, sticky discharge, and your cat may appear to be constantly uncomfortable.
Corneal ulcers: These are open sores on the eye. They’re painful and often linked to feline herpes. Left untreated, they can lead to scarring or even vision loss.
Cherry Eye: Not true conjunctivitis, but it’s often confused with it. This condition causes the third eyelid gland to protrude, forming a visible, red bulge. It usually needs surgery to fix.
What are the Symptoms of Conjunctivitis in Cats?
The most noticeable symptom of conjunctivitis is the presence of redness and swelling of the eyes, which is why it’s commonly referred to as pink eye in cats.
Here are the common symptoms of conjunctivitis in cats:
Red, swollen eyes
Eye discharge
Squinting or excessive blinking
Sensitivity to light
Pawing or rubbing at the eyes
Visible third eyelid
How is Conjunctivitis in Cats Diagnosed?
Diagnosing this condition is quite simple with the tools and experience we have. Here’s a guide on the tests and methods we use to diagnose conjunctivitis in cats:
Eye Examination
Using specialized light or magnification tools, our experts thoroughly inspect your cat’s eyes. If your cat’s eyes have conjunctivitis, we’ll see any signs of damage, inflammation, or infection. These are clues that help us where to proceed to next.
Cytology
We take a small sample from your cat’s eye, either discharge or cells from the conjunctiva. This helps us see what kind of inflammation is present and whether bacteria, fungi, or other cells are involved.
Culture and Sensitivity Test
We collect a discharge sample and grow it in our lab. This tells us exactly which bacteria are causing the problem and which antibiotics will actually work.
Fluorescein Staining
A safe, glowing dye is placed on the eye’s surface. It shows any scratches, ulcers, or hidden damage. The dye washes away after the exam, but helps us see issues that aren’t always visible.
Polymerase Chain Reaction
This test finds the DNA of viruses like feline herpes. It’s extremely sensitive and helps us catch infections early, even before other signs show up.
Allergy or Environmental Assessments
If there’s no infection, we look at lifestyle. Sometimes the cause is in the home, like scented litter, cleaners, or even food. We may suggest changes to reduce flare-ups.
How is Conjunctivitis in Cats Treated?
Once conjunctivitis has been diagnosed in your cat, we’ll proceed to treatment. Because of the variety of causes, the options for getting rid of pink eye in cats will vary as well.
Antibiotic Treatments
If a bacterial infection is the culprit, we’ll most likely prescribe antibiotic medications in the form of eye drops or ointments. These are applied directly to the eye to combat the infection and reduce inflammation. Common choices include:
Chloramphenicol
Oxytetracycline
Tobramycin
Typical dosage: 1–2 drops per eye, 2–3 times daily for 7–10 days, depending on severity and response.
Antiviral Therapies
Dealing with viral infections like feline herpesvirus (FHV-1) can be trickier, as these can’t be cured entirely. Treatment focuses on reducing flare-ups and keeping your cat comfortable. In some cases, we may prescribe:
Famciclovir, often dosed at 90 mg/kg orally, twice daily, is particularly effective against FHV-1.
Supportive care remains key, helping your cat through stress reduction, hydration, and good nutrition.
Anti-Inflammatory Medications
To ease your cat’s discomfort, we might prescribe anti-inflammatory meds.
NSAIDs help reduce general inflammation.
Corticosteroids (like dexamethasone) can calm things down, too, but only if we’re sure there are no corneal ulcers. Steroids can make ulcers worse.
Cyclosporine Eye Drops
If your cat has dry eye, we may use Cyclosporine. It helps the eyes make more natural tears and keeps them moist. It’s dosed at:
0.2%–2% applied twice daily, depending on your cat’s individual response.
In resistant cases, tacrolimus may be considered as an alternative.
Artificial Tears
Artificial tear drops can help keep the eyes moist and reduce discomfort in both infectious and non-infectious cases. These are especially useful for cats with allergies or environmental irritants, or those prone to chronic dryness.
Emerging Therapies and Immune Support
Some newer things are being tried, especially for cats with stubborn or repeat flare-ups.
L-Lysine may help lower how often herpes shows up.
Serum eye drops use your cat’s own blood to help the eyes heal.
Immune boosters (like omega-3s) might help cats with weak immune systems.
Veterinary Treatment Protocols: What to Expect
Not every case of conjunctivitis is simple. Some need a closer look, especially when symptoms don’t go away or keep coming back.
When Steroids Can Help
Topical steroids can calm inflammation fast. They’re useful when the cause is an allergy or an immune-related issue. But here’s the catch: we only use them after doing a fluorescein stain test. That’s how we check for corneal ulcers first.
Steroids help with:
Allergic conjunctivitis
Autoimmune-related eye inflammation
When Steroids Can Make Things Worse
Steroids aren’t safe for every case. If there’s a virus involved, like feline herpes, it can slow healing or even make the infection worse. The same goes for ulcers or any damage to the cornea.
Avoid steroids if your cat has:
Feline herpesvirus (FHV-1)
Corneal ulcers or trauma
Any active infection not checked by a vet
If you’ve got old eye drops at home, don’t reuse them. Especially not steroids. They’re powerful, but only when used the right way, at the right time.
When to Refer to a Veterinary Ophthalmologist
Your general vet may recommend referral to a specialist if:
The condition persists for more than 2–3 weeks despite appropriate treatment
There's evidence of deep ulcers, trauma, or scarring
Autoimmune eye diseases are suspected
There is vision loss or severe discomfort
Specialists have access to advanced diagnostic tools and therapies such as grafting procedures, immunomodulating medications, and diagnostic imaging that can uncover hidden causes.
How to Prevent Conjunctivitis in Cats?
Sometimes, a few small habits can make a big difference. Preventing pink eye isn’t complicated, but it does take consistency.
Take your cat for checkups. A vet can spot early signs of trouble, even before your cat shows symptoms. Eyes included.
Keep vaccinations current. Infections like feline herpesvirus or calicivirus can trigger conjunctivitis. Staying on top of vaccines lowers the risk.
Clean their space. Cats are clean creatures, but their environment matters too. Wipe surfaces, wash bedding, and don’t forget the litter area to avoid eye infections.
Groom Your Cat. Grooming isn’t just about looks. A clean face, especially around the eyes, can help stop dust, fur, and bacteria from building up.
“Bright, clear eyes are a sign of a healthy cat. Protecting them means protecting your cat’s comfort and happiness.”
- Dr. Lidija Krvavac
Final Thoughts
Conjunctivitis in cats is a common eye problem that can cause significant pain and discomfort. While the issue can be managed and treated, it’s always important to take steps to prevent anything from getting in the way of your cat’s health and happiness.
Frequently Asked Questions
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