Conjunctivitis in cats – symptoms, causes and home treatments

Conjunctivitis, also known as pink eye, is a common condition that affects cats of all ages and breeds. This infection targets the thin, transparent membrane known as the conjunctiva, which lines the inside of a cat’s eyelid and the white part of the eyeball. While conjunctivitis in cats, or cat conjunctivitis, is not typically life-threatening, it can be very uncomfortable and, in severe cases, lead to permanent damage if left untreated. The key to protecting your cat from long-term harm is early detection and prompt treatment.

Understanding the causes, symptoms, and effective home treatments for conjunctivitis is crucial for every cat owner. Whether your feline companion has watery eyes, redness, or swelling, knowing how to properly respond to these signs can make all the difference in their recovery.

What is conjunctivitis in cats?

Conjunctivitis in cats, or inflammation of the conjunctiva, can be caused by a variety of factors, ranging from viral and bacterial infections to allergies and environmental irritants. This inflammation causes the blood vessels in the conjunctiva to dilate, leading to redness, swelling, and discomfort. While many cases of conjunctivitis resolve with proper care, chronic or untreated cases can result in more severe complications such as cat eye infection, corneal damage or loss of vision.

There are two main types of conjunctivitis in cats: infectious and non-infectious. Infectious conjunctivitis is caused by bacteria, viruses or fungi, while non-infectious conjunctivitis can result from allergens, irritants or injuries. Identifying the type of conjunctivitis your cat is suffering from is essential for determining the best course of treatment.

Symptoms of cat conjunctivitis

The symptoms of cat conjunctivitis can range from mild to severe depending on the underlying cause and how quickly the condition is addressed. Some of the most common symptoms include:

Redness in the eye: One of the most noticeable symptoms of conjunctivitis is redness in the affected eye. This is caused by the dilation of blood vessels in the conjunctiva, which leads to visible irritation.
Swollen eyelids and conjunctiva: The inflammation caused by conjunctivitis often results in swollen eyelids and a puffy appearance around the eye. This can make it uncomfortable for your cat to open its eye fully.
Excessive tearing: Watery eyes or excessive tear production is a common symptom of conjunctivitis. The body produces more tears to flush out irritants or combat infections, which can lead to a constant flow of tears from one or both eyes.
Eye discharge: The type and amount of discharge from your cat’s eye can vary depending on the severity of the condition. In mild cases, the discharge may be clear and watery, while in more serious cases, it can be thick, yellow or green, indicating a bacterial infection.
Squinting or blinking: Cats with conjunctivitis often squint or blink excessively in an attempt to relieve discomfort. This is a protective response to the irritation caused by the infection.
Cat rubbing its eyes: Cats suffering from conjunctivitis may frequently rub their eyes with their paws in an attempt to alleviate the itching or discomfort. However, this can further irritate the eye and spread the infection if not addressed.
Sensitivity to light: Some cats with conjunctivitis may become sensitive to light and prefer to stay in darker areas. This condition, known as photophobia, can be a sign that the infection is causing more severe irritation.
Third eyelid appearance: In some cases, you may notice the third eyelid of your cat becoming more visible or protruding. This is a protective response to the irritation or infection affecting the eye.

Early detection of these symptoms is crucial for preventing the infection from getting worse or spreading. Left untreated, conjunctivitis can lead to more severe conditions, such as corneal ulcers or chronic infections that require long-term treatment.

A fluffy cat with green eyes lying on the floor.

Mild vs severe conjunctivitis symptoms

Not all cases of conjunctivitis in cats are the same. Some cases may present as mild, with only slight redness and watery eyes, while others can be more severe involving thick discharge, significant swelling and visible discomfort. Here’s how you can differentiate between mild and severe symptoms:

Mild conjunctivitis: In these cases, your cat may experience minor symptoms, such as a slightly red eye, mild tearing or squinting. The cat may still be active and show no signs of pain. Mild conjunctivitis can often be treated with home remedies and may resolve on its own with proper care.
Severe conjunctivitis: Severe cases of conjunctivitis typically involve more obvious symptoms, such as thick discharge (green or yellow), swollen eyelids and significant redness. Cats with severe conjunctivitis may show signs of discomfort, avoid bright lights and have difficulty opening their eyes fully. These cases usually require immediate veterinary attention and possibly prescription medication.

It’s important to monitor your cat’s symptoms closely and seek veterinary care if you notice any worsening signs, particularly if they involve the cat's swollen eye, thick discharge or signs of pain.

Causes of conjunctivitis in cats

Conjunctivitis in cats can have several different causes, each of which requires a tailored approach to treatment. Here are the most common causes of conjunctivitis in cats:

Viral infections

The most frequent cause of conjunctivitis in cats is a viral infection, particularly from the feline herpesvirus (FHV-1). FHV-1 is a highly contagious virus that can cause upper respiratory infections in cats, along with conjunctivitis. Once a cat is infected, the virus can remain dormant in the body and reactivate during periods of stress, illness, or weakened immunity.

Cats with viral conjunctivitis may exhibit both eye and respiratory symptoms, such as sneezing, nasal discharge and coughing. Viral conjunctivitis often recurs throughout a cat’s life, particularly during times of stress. While there is no cure for feline herpesvirus, antiviral medications and supportive care can help manage symptoms.

Bacterial infections

Bacterial infections are another leading cause of conjunctivitis in cats. Chlamydia felis and Mycoplasma are two common bacteria that can infect a cat’s eyes and lead to conjunctivitis. These infections are often secondary, meaning they occur in conjunction with viral infections or after an injury to the eye.

Bacterial conjunctivitis is typically more severe than viral conjunctivitis and often involves thick, yellow, or green discharge from the eye. Antibiotics are usually required to treat bacterial conjunctivitis and prevent further complications.

Allergies

Environmental allergies are another common cause of conjunctivitis in cats. Allergens such as pollen, dust, mold and chemicals can irritate the sensitive tissues in your cat’s eyes, leading to allergic conjunctivitis. Unlike infectious conjunctivitis, allergic conjunctivitis usually affects both eyes and may be accompanied by other allergic symptoms, such as sneezing, itching or skin irritation.

Allergic conjunctivitis is more common in the spring and summer when pollen levels are higher. If you suspect your cat’s conjunctivitis is caused by allergies, it’s important to limit exposure to known allergens and consult your veterinarian about potential treatments.

Foreign bodies or trauma

Cats are naturally curious and can sometimes get foreign objects such as dirt, grass, or small particles stuck in their eyes. This can cause irritation and inflammation, leading to conjunctivitis. Additionally, scratches or injuries to the eye from playing or fighting with other animals can result in sore eye or swelling.

In these cases, conjunctivitis will often clear up once the foreign body is removed or the injury heals. However, it’s important to monitor the affected eye closely to ensure it doesn’t become infected. If your cat’s eye does not improve within a few days, veterinary attention may be required.

Irritants

Smoke, strong household cleaners, perfumes and other irritants can cause non-infectious conjunctivitis. Cats are particularly sensitive to airborne chemicals and even minor exposure can lead to red watery eyes. If you notice your cat developing conjunctivitis after exposure to certain products, consider switching to pet-safe alternatives and improving ventilation in your home.

How to diagnose conjunctivitis in cats

If your cat is showing signs of conjunctivitis, it’s important to have the condition properly diagnosed by a veterinarian. During a veterinary exam, your vet will assess the eye's condition, ask about any recent exposure to other animals and possibly perform tests to identify the cause of the conjunctivitis.

Some diagnostic tools include:

Fluorescein eye stain test: This test involves applying a fluorescent dye to your cat’s eye to check for any damage to the cornea, such as ulcers or scratches. The dye will highlight any areas of injury, allowing the vet to assess whether conjunctivitis is secondary to trauma.
Schirmer tear test: This test measures tear production in your cat’s eye to determine if they have dry eye syndrome, which can contribute to conjunctivitis.
Swab tests: If bacterial or viral infections are suspected, your vet may take a swab of the eye’s discharge for laboratory testing. This will help identify the exact type of infection and guide treatment options.

Prompt diagnosis and treatment are crucial for preventing more serious complications, such as vision loss or chronic infection.

Treating cat conjunctivitis

The treatment for conjunctivitis in cats depends on the underlying cause of the infection. In many cases, home treatments can help alleviate symptoms and promote healing but more severe cases may require prescription medication. Here’s an overview of the most common treatments for cat conjunctivitis:

Home treatments for mild cases

If your cat has a mild case of conjunctivitis, there are several home remedies you can try to help relieve symptoms:

Warm compresses: Gently applying a warm, damp cloth to the affected eye for a few minutes can help reduce swelling and soothe irritation. Make sure to use a clean cloth for each eye if both are affected.
Saline rinses: Flushing the eye with a saline solution can help remove debris and reduce irritation. You can use sterile saline solution from your local pharmacy, or your veterinarian may recommend a specific eye wash product for cats.
Artificial tears: If your cat has dry or irritated eyes, over-the-counter artificial tears (designed for pets) can help provide relief. Apply a few drops to the affected eye as directed by your vet.

Prescription treatments for severe cases

For more severe cases of conjunctivitis, your veterinarian may prescribe one or more of the following treatments:

Antibiotic eye drops or ointments: If your cat’s conjunctivitis is caused by a bacterial infection, antibiotic eye drops or ointments will be prescribed. These medications should be applied directly to the affected eye several times a day.
Antiviral medications: For cases of viral conjunctivitis, particularly those caused by feline herpesvirus, antiviral medications may be necessary. These can help reduce the severity of symptoms and prevent future outbreaks.
Anti-inflammatory drugs: If your cat’s conjunctivitis is causing significant swelling or discomfort, your vet may prescribe anti-inflammatory eye drops to reduce inflammation and pain.

It’s important to follow your veterinarian’s instructions carefully and complete the full course of treatment even if your cat’s symptoms improve. Stopping treatment too early can result in the infection returning or becoming resistant to medications.

When to seek veterinary care

While mild cases of conjunctivitis can often be treated at home, certain situations require immediate veterinary attention. You should contact your vet if:

Symptoms worsen: If your cat’s eye becomes more swollen, red or irritated despite home treatment, this could indicate a more serious problem.
There is persistent discharge: Thick, green, or yellow discharge from the eye is a sign of a bacterial infection that requires antibiotics.
Your cta has vision problems: If your cat seems to have difficulty seeing or is bumping into objects, it could indicate that the infection is affecting their vision.
There are ystemic symptoms: If your cat is showing signs of illness such as fever, loss of appetite or respiratory symptoms, it may be suffering from a systemic infection that requires more aggressive treatment.

In these cases, prompt veterinary care can prevent further complications and help your cat recover quickly.

Preventing conjunctivitis in cats

Preventing conjunctivitis in cats involves taking steps to reduce your cat’s exposure to potential irritants, infections and injuries. Here are some ways you can help protect your cat’s eye health:

Vaccinations: Keeping your cat up to date on vaccinations, particularly for feline herpesvirus, can help prevent viral conjunctivitis. Talk to your veterinarian about the appropriate vaccination schedule for your cat.
Hygiene: Regularly cleaning your cat’s living environment, including their bedding, toys and food bowls, can reduce the risk of bacterial infections. If you have multiple cats, make sure to isolate any cat with conjunctivitis to prevent the spread of infection.
Minimising stress: Since stress can trigger outbreaks of feline herpesvirus, it’s important to keep your cat’s environment as calm and stable as possible. Avoid sudden changes in routine, provide plenty of enrichment, and ensure your cat has a quiet space to retreat to when needed.
Avoid exposure to irritants: Keep your cat away from strong chemicals, smoke or other irritants that can cause eye inflammation. Use pet-safe cleaning products in your home and ensure proper ventilation.

Conclusion

Conjunctivitis in cats is a common eye condition that, while typically not life-threatening, can cause significant discomfort for your feline companion. By understanding the symptoms, causes and treatment options, you can help your cat recover quickly and prevent future episodes. If you notice any signs of cat conjunctivitis, it’s important to take action quickly, either with home treatments or by seeking veterinary care. With proper attention, your cat can enjoy clear, healthy eyes and a better quality of life.