Short, short, short. Long, long, long. Short, short, short.
Is your cat winking at you in Morse code? Maybe your dreams have finally come true and your cat is signaling that it’s time to start your new lives as a crime-solving duo! But before you grab your magnifying glass and matching trench coats, take a closer look at that 'signal.' Unless their first big case is 'The Mystery of the Crusty Eyelid,' your partner-in-crime is likely sending a different kind of SOS: a case of feline conjunctivitis.
Conjunctivitis is the most common eye problem in cats. Also called pink eye, this condition causes the thin membrane lining your cat's eyelids to become red, swollen, and irritated. If your cat is squinting, pawing at their face, or has watery or gunky eyes, conjunctivitis is likely the culprit.
The good news is that most cases respond well to treatment. While pink eye can look alarming, especially when your cat's eyes are swollen or producing colored discharge, a trip to the vet and some eye drops usually clears things up within a week or two. However, because eye problems can worsen quickly, it's important to know when home monitoring is fine and when your cat needs professional care.
Many cats develop conjunctivitis alongside upper respiratory symptoms like sneezing and a runny nose. This happens because feline herpesvirus, the leading cause of cat pink eye, affects both the eyes and respiratory system.
What Is Conjunctivitis in Cats?
Conjunctivitis is inflammation of the conjunctiva, the thin, delicate pink tissue that lines the inside of your cat's eyelids and covers the white part of the eyeball. When this membrane becomes irritated or infected, it turns a deeper pink or red color, swells, and produces excess tears or discharge.
Cats also have a third eyelid, called the nictitating membrane, which sits in the inner corner of each eye. You might not notice it in a healthy cat, but when conjunctivitis strikes, this membrane often becomes visible and inflamed, partially covering the eye.
The conjunctiva serves an important purpose. It helps lubricate the eye by distributing tears across the surface and contains antibodies that fight off infection. When this protective tissue becomes inflamed, your cat's eye loses some of its natural defense against bacteria and irritants.
Conjunctivitis can affect one or both eyes. It often starts in one eye and spreads to the other within a few days. Most cats experience at least one episode during their lifetime, and cats who carry feline herpesvirus may have recurring flare-ups throughout their lives.
Symptoms of Cat Pink Eye
Conjunctivitis symptoms are usually easy to spot. Here's what to look for:
Eye symptoms:
Redness and swelling of the tissue around the eyeball
Discharge (clear and watery, white and mucoid, or thick and yellow/green)
Squinting, excessive blinking, or holding the eye partially closed
Pawing at the face or rubbing the eye against furniture
Third eyelid visible and protruding from the inner corner
Crusty buildup around the eyes, especially after sleep
Other symptoms (common with viral infections):
Nasal discharge
Decreased appetite
Lethargy
If your cat has both eye and respiratory symptoms, feline herpesvirus or calicivirus is likely the cause. These are the two most common viral triggers for pink eye in cats.
What Eye Discharge Color Means
It’s a common misconception that conjunctivitis is a single disease you can cure with a generic bottle of drops. In reality, conjunctivitis is merely a symptom. Think of it as the "cough" of the eye; just as a cough can mean anything from a tickle in the throat to pneumonia, pink eye can be caused by a dozen different culprits. This is why veterinarians obsess over the color of that "gunk." It helps us identify and treat the underlying cause.
Discharge Type | What It Often Indicates |
Clear, watery | Viral infection, allergies, or mild irritant |
White or mucoid | Early infection or allergies |
Yellow or green, thick | Bacterial infection (primary or secondary) |
Crusty buildup | Ongoing infection; discharge drying overnight |
Bloody or dark | Trauma, severe infection, or ulcer (see a vet immediately) |
What Causes Conjunctivitis in Cats?
Several things can trigger conjunctivitis, and identifying the underlying cause helps determine the right treatment. Unlike dogs, where allergies are a leading cause of pink eye, viral infections dominate in cats.
Viral Infections
Feline herpesvirus-1 (FHV-1) is the number one cause of conjunctivitis in cats, particularly recurring cases. This virus is extremely common. Most cats from shelters, rescues, or multi-cat environments have been exposed at some point. Once a cat contracts herpesvirus, the virus remains dormant in their nervous system for life. It can reactivate during times of stress, illness, surgery, or anything that suppresses the immune system.
Feline calicivirus is another common viral cause. Like herpesvirus, calicivirus spreads through eye, nose, and mouth secretions, and many cats become lifelong carriers after recovering from the initial infection. Both viruses are highly contagious to other cats but cannot infect humans or dogs.
Bacterial Infections
Bacteria can cause conjunctivitis on their own or move in as a secondary infection after a virus weakens the eye's defenses. Common culprits include Chlamydophila felis, Mycoplasma, Staphylococcus, and Streptococcus.
Chlamydophila felis deserves special mention because, in rare cases, it can spread to immunocompromised humans and cause eye infections. If your cat is diagnosed with chlamydial conjunctivitis, wash your hands thoroughly after handling them, especially before touching your own face.
Allergies and Irritants
Environmental allergens like pollen, dust, and mold can trigger conjunctivitis in some cats. Household irritants such as cigarette smoke, cleaning chemicals, perfumes, or dusty cat litters may also cause eye inflammation. Allergic conjunctivitis is less common in cats than in dogs, and it typically affects both eyes at the same time.
I have seen cats develop conjunctivitis from diffusing essential oils. Not only are some essential oils extremely toxic to cats, due to their concentrated form, all can be very irritating to the respiratory tract and eyes. Never diffuse any essential oils around your cat, especially in a confined area, and always speak to your vet before using essential oils in any other way on or around your cat.
Other Causes
Less common causes include foreign bodies (grass seeds, dust, debris), trauma or scratches to the eye, underlying conditions like corneal ulcers or glaucoma, and eyelid abnormalities where the lid rolls inward and irritates the eye. In rare cases, immune-mediated conditions or tumors can cause chronic conjunctivitis.
Comparing Viral, Bacterial, and Allergic Conjunctivitis
Feature | Viral | Bacterial | Allergic |
Discharge type | Clear to mucoid | Yellow or green, thick | Clear, watery |
One or both eyes? | Often starts in one, spreads to both | Can be one or both | Usually both |
Respiratory symptoms? | Common (sneezing, nasal discharge) | Less common | Can also cause sneezing, coughing, nasal discharge |
Recurs with stress? | Yes (herpesvirus flares) | Not typically | May follow seasonal patterns |
Contagious to other cats? | Yes | Yes | No |
When to See a Vet
Eye problems can escalate quickly, and some conditions that look like simple conjunctivitis, such as corneal ulcers, require different treatment. When in doubt, call your vet.
You can monitor at home for 12 to 24 hours if your cat has mild redness with minimal swelling, clear watery discharge only, no squinting or eye held closed, normal appetite and energy, and symptoms that just appeared within the last day.
See a vet within one to two days if symptoms persist beyond 24 to 48 hours, discharge turns yellow or green, your cat is squinting or blinking more than usual, both eyes become affected, your cat has mild sneezing or nasal discharge, or your cat seems slightly "off" but isn't in obvious distress.
See a vet today or seek emergency care if:
The eye is swollen shut or significantly bulging.
Your cat is squinting or holding the eye completely closed, which indicates significant pain.
There is bloody or dark discharge (this is never "normal" pink eye).
You notice cloudiness or a color change on the surface of the eyeball itself.
There is a visible injury, scratch, or foreign object in the eye.
Your cat shows obvious signs of pain, such as crying out, hiding, or not letting you touch their face.
The patient is a kitten under eight weeks old (in kittens, eye infections can turn permanent in a matter of hours).
Systemic symptoms appear, like a total loss of appetite or severe lethargy.
Symptoms are worsening rapidly.
How Vets Diagnose Cat Conjunctivitis
Diagnosing conjunctivitis involves more than confirming that the eye looks irritated. Your vet needs to rule out other eye conditions and, ideally, identify the underlying cause so they can prescribe the most effective treatment.
The examination starts with a visual inspection of both eyes and the surrounding tissue. Using a lighted instrument called an ophthalmoscope, your vet will look at the eye's structures, check for foreign bodies, assess the third eyelid, and evaluate whether the eyelids sit in the correct position.
A fluorescein stain test is one of the most important diagnostics. Your vet places a drop of orange dye on the eye's surface. The dye highlights any scratches or ulcers on the cornea, which is critical information because corneal ulcers require different treatment than simple conjunctivitis. This test is quick and painless.
Your vet may also perform a Schirmer tear test, which uses a small paper strip to measure tear production and rule out dry eye. If glaucoma is a concern, they may measure the pressure inside the eye using a tonometer.
For suspected bacterial infections, a conjunctival swab allows the lab to identify the specific bacteria involved and determine which antibiotics will work best. If your cat hasn't been tested recently, your vet might recommend blood tests for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV), since immunocompromised cats are more susceptible to chronic eye infections.
Cat Conjunctivitis Treatment
Treatment depends on what's causing the conjunctivitis, but most cases require topical medications applied directly to the eye two to four times daily. Plan on one to three weeks of treatment for uncomplicated cases.
Topical Eye Medications
Antibiotic eye drops or ointment are the mainstay of treatment. Even when a virus is the primary cause, antibiotics help prevent or treat secondary bacterial infections. Common options include oxytetracycline (Terramycin), tobramycin, and erythromycin. Ointments stay in the eye longer than drops but can temporarily blur your cat's vision.
For cats with herpesvirus, your vet may prescribe antiviral eye drops such as idoxuridine, cidofovir, or trifluridine. These are often used alongside antibiotics. Some combination drops contain both an antibiotic and an anti-inflammatory ingredient to reduce swelling and discomfort.
Oral Medications
When topical treatment alone isn't enough, or when a cat absolutely refuses eye drops, oral medications become necessary. Famciclovir is an antiviral pill used for severe or systemic herpesvirus infections. It's also a good option for cats who fight every attempt to medicate their eyes.
Oral antibiotics may be prescribed for bacterial infections that have spread beyond the eye. Azithromycin is commonly used when Chlamydophila felis is suspected.
Supportive Care
L-lysine is an amino acid supplement often recommended for cats with herpesvirus. It's available as treats, powder, or paste and is thought to help suppress viral replication. Research on its effectiveness has been mixed, but many vets still recommend it because it's safe and some owners report improvement.
Keeping your cat's environment calm and stress-free is particularly important for herpesvirus cats, since stress triggers flare-ups. Providing a quiet space, maintaining a consistent routine, and using pheromone products like Feliway can help.
Most cats show improvement within three to seven days of starting treatment. Complete resolution typically takes one to two weeks for uncomplicated cases, though herpesvirus-related conjunctivitis may take longer and can recur.
How Much Does Cat Conjunctivitis Treatment Cost?
The cost of treating cat conjunctivitis varies depending on your location, the veterinary clinic, and how severe your cat's condition is. A straightforward case that needs only an exam and basic eye drops will cost much less than a complicated case requiring multiple diagnostic tests, specialty medications, or ongoing treatment.
Factors that affect cost:
Initial exam and diagnostic tests (fluorescein stain, tear production test, eye pressure check)
Type of medication prescribed (basic antibiotics vs. antivirals vs. oral medications)
Whether lab work is needed (bacterial culture, FeLV/FIV testing)
Follow-up visits to monitor healing
Chronic or recurring cases that need long-term management
Cats with feline herpesvirus often experience flare-ups throughout their lives, which means repeated vet visits and medication costs that add up over time. Here are some possible costs:
Service Category | Item / Procedure | Estimated Cost (2026) |
|---|---|---|
Initial Visit | Physical Exam Fee | $60 – $120 |
Diagnostic Tests | Fluorescein Stain (Checks for ulcers) | $25 – $50 |
Schirmer Tear Test (Checks for dry eye) | $25 – $45 | |
Tonometry (Checks eye pressure) | $30 – $75 | |
Medications | Antibiotic Drops or Ointment | $20 – $45 |
Antiviral Eye Drops (for Herpesvirus) | $50 – $130 | |
Oral Antivirals (e.g., Famciclovir) | $40 – $100 | |
Recurring / Chronic | L-Lysine Supplements (Monthly) | $15 – $30 |
Stress Relief (Pheromone Diffusers) | $25 – $60 | |
Maintenance Lubricant Drops | $15 – $35 | |
Advanced Lab Work | Viral PCR Panel / Bacterial Culture | $150 – $300 |
FeLV/FIV Testing | $45 – $90 |
In 2026, most pet parents should expect to spend between $125 and $450 for a complete course of treatment, though severe or chronic cases requiring emergency care or advanced diagnostics can easily climb toward $1,000.
How Pet Insurance Can Help
Eye conditions like conjunctivitis are covered under Embrace's accident and illness policies. Pet insurance can help offset the cost of diagnosis, medications, and follow-up care, which is especially valuable for cats with chronic or recurring issues. Instead of worrying about the bill, you can focus on getting your cat the care they need.
Because most insurance providers won't cover pre-existing conditions, it’s vital to have coverage in place before your cat shows symptoms; this ensures that future flare-ups and complications are covered throughout your cat’s life. Cat insurance gives you peace of mind knowing unexpected vet bills won't derail your budget.
If your cat needs routine eye care or preventive supplements like L-lysine, Embrace Wellness Rewards can help with those ongoing costs too. This optional plan helps you budget for everyday care expenses that standard insurance doesn't cover.
Home Remedies for Cat Pink Eye
There's limited safe intervention you can do at home, but a few steps can keep your cat comfortable until you get to the vet.
Gently clean discharge from around the eye using a warm, damp cloth or cotton ball. Wipe from the inner corner of the eye outward, and use a separate cloth for each eye to avoid spreading infection. Don't press on the eyeball itself.
Keep your cat comfortable by reducing stress, maintaining access to food, water, and the litter box, and giving them a quiet place to rest. If you have other cats, isolate the affected cat to prevent spreading the infection. Use separate food and water bowls and wash your hands after handling the sick cat.
Monitor symptoms and take notes or photos to show your vet. Document any changes in discharge color, whether symptoms are getting better or worse, and whether your cat is eating and behaving normally.
Don't use human eye drops or OTC medications: Many contain ingredients (like decongestants) that are toxic to cats. Using them can also mask underlying symptoms, leading to a dangerous delay in a proper diagnosis.
Don't apply Neosporin or triple-antibiotic ointments: These are not formulated for ophthalmic use and can cause life-threatening allergic reactions (anaphylaxis) in some cats.
Don't attempt to remove a foreign object yourself: If you see something stuck in the eye, trying to "pluck" it out can cause the eye to rupture or lead to permanent corneal scarring.
Don't wait if symptoms worsen: Eye conditions are not "wait and see" issues. A simple irritation can turn into a deep corneal ulcer or permanent vision loss in just 24 to 48 hours.
Conjunctivitis in Kittens
Kittens face the highest risk for conjunctivitis. Their immune systems are still developing, and exposure to viruses like herpesvirus is extremely common in shelters, catteries, and foster homes. Kittens often contract eye infections from their mother or littermates.
Eye infections in very young kittens are particularly concerning because they can progress rapidly. Warning signs include eyes crusted shut (especially in kittens under two weeks old whose eyes recently opened), severe swelling of the eyelids, heavy pus or discharge, kittens who aren't nursing or eating, and lethargy or weakness.
Any eye symptoms in a kitten under four weeks old should be treated as an emergency. Eyes glued shut with discharge, visible bulging behind closed eyelids, or a kitten who seems weak, cold, or isn't eating all require immediate veterinary attention. Untreated eye infections in very young kittens can lead to permanent eye damage or loss of the eye.
How to Prevent Cat Conjunctivitis
You can't always prevent conjunctivitis, but you can reduce the risk and minimize flare-ups.
Key prevention tips:
Reduce stress (the biggest trigger for herpesvirus flares) by maintaining a consistent routine and providing quiet spaces
Keep the environment clean with regular bedding washes and low-dust litter
Isolate sick cats in multi-cat households and don't share food bowls or bedding
Talk to your vet about L-lysine supplements for cats with recurring flares
Start treatment early at the first sign of symptoms
Regular vet visits and keeping vaccinations current also support overall immune health.
Cat Wink or Cat Pink Eye?
The next time your cat starts "winking" at you in Morse code, remember that they aren't trying to recruit you for a high-stakes spy mission or solve a neighborhood mystery. That rhythmic squint is a biological SOS—a signal that their eye’s natural defenses have been breached. Don’t ignore the signal; once you decode the cause and start the right treatment, you’ll have your partner-in-crime back to their clear-eyed, observant self in no time.