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Why Are My Cat's Eyes Red?

Why Are My Cat's Eyes Red?

Injury, disease, infections, and other factors can contribute to red eye in cats. In this post, our Renton veterinarians discuss each of these in detail, how these conditions are diagnosed, and which treatment options exist.  

What a Cat's Red Eye Can Tell Us

Your cat's eyes should normally be clear and reveal their natural color. However, sometimes you may look into your favorite furry feline's face to discover their eyes are red, irritated, or inflamed. 

Our veterinary ophthalmologists sometimes have alarmed clients ask us, 'Why is my cat's eye red?'. Our answer is always that many potential health issues, including injury, disease, infection, irritants, allergies, obstructions, or changes in the eyelids or eyelashes. Swelling or inflammation may also be present. 

Each of these should be addressed by a vet or veterinary ophthalmologist as soon as possible to treat symptoms and prevent or reduce the risk of long-term damage to your cat's eyesight. 

Today, we'll explore what to look for if you think your cat may have an eye problem and the potential reasons your cat's eyes are red, before getting into diagnosis and treatment for this symptom. 

Does Your Cat Spend Time Indoors or Outdoors?

If your kitty spends a significant amount of time outdoors, they'll be at higher risk of encountering issues such as:

  • Bees
  • Grass
  • Plants
  • Pollen 
  • Other animals 
  • Accidental scrapes or pokes 

While cats may love to venture outside, these explorations sometimes have a cost. In addition, it can become more difficult to detect the cause of your cat's red eyes if they've been outside among many possible sources of symptoms. 

What to Look For If Your Cat's Eyes Are Red

Some factors can indicate potential causes behind your cat's red eyes, and how serious the situation is. These include: 

Redness in One or Both Eyes 

Identifying whether one or both eyes are red may yield some clues as to the cause of the change in hue. While an injury will typically only affect one eye, bacterial and viral infections are more likely to impact the appearance of both eyes. 

Also, establish whether your cat can open their eye(s). If not, this points to a more serious problem.

Location of the Redness

If the tissue is red and swollen, or so swollen that you're unable to see the eye itself, the issue may be with the membranes around the eye (the conjunctiva). 

In contrast, if the whites of the eyes are inflamed and seem bloodshot, this may be a problem that will go away quickly (similar to how people's eyes sometimes appear bloodshot) with no serious cause. 

A third possibility is that there's a third eyelid covering the eye. This whitish structure will cover the nose side of the eye at an angle to help protect the eye when it's sore. If this membrane is raised, the eye may have an alarming appearance. 


The presence and color of any discharge can be one indicator of how serious your cat's eye problem is. While bloody discharge can point to a serious injury, an infection will more commonly cause yellow or green discharge. 

An accumulation of mucus will often result in thicker discharge, and excess tearing can often lead to thinner discharge. 

What to Do If Your Cat Has Red Eyes 

Always see your vet or veterinary ophthalmologist if you notice that your cat's eyes are red. They'll be able to diagnose the cause of this concerning symptom and recommend treatment that may prevent your cat from losing their vision or potentially their eye. 

Redness, swelling, or discharge from the eye, along with being unable to open the eye, are veterinary emergencies

If your cat can open their eyes, the redness is mild, and your feline friend seems to be feeling well otherwise, you can likely wait up to 48 hours for an appointment with your veterinarian. If you aren't sure, contact your primary vet for advice. 

Common Causes of Red Eye in Cats

Many conditions can impact the appearance of your cat's eyes and their eyesight. While some of these issues concern the eye (globe) itself, others impact the tissue surrounding the eye. Conditions affecting the globe are typically more serious than conditions affecting the tissue. 


Because infections are always at risk of worsening, we recommend booking an appointment with your vet or veterinary ophthalmologist right away if you notice that your cat has a red eye. Bacterial or viral infections need to be treated and monitored as soon as possible. 


Also referred to as pink eye, conjunctivitis is the most common cause of red eye in cats. Typically the result of bacterial infection, conjunctivitis can also cause clear or dark fluid discharge, excessive winking, watery eyes, and swollen eye tissue. Your cat's eyes may also become extremely itchy and irritated. 

Injury or Trauma

If your cat spends time outdoors, they are more likely to get into fights with other animals. Even if they are exclusively indoors, too much roughhousing can cause injury or trauma due to scratches or bites, which can lead to redness. 

It's important to prevent injury or trauma from becoming infected and to get the proper treatment and diagnosis to reduce the risk of your cat's vision deteriorating. If you notice that your cat has a red eye or an eye injury, book an appointment with your vet right away. 

Chronic Diseases

Similar to other animals, cats are at risk of developing cancer and autoimmune conditions. Various cancers can affect your kitty's eyes, particularly feline lymphosarcoma-leukemia complex. Autoimmune disorders may lead to a condition known as uveitis, which can cause eye inflammation. 

Less Common Causes of Red Eye in Cats 

  • Allergies (e.g. dust, pollen, or bee stings)
  • Irritants (e.g. cigarette smoke, candles, air fresheners, or perfumes)
  • Obstructions (e.g. dirt or grass)
  • Glaucoma
  • Hyphema (bleeding into the front of the eye)

Diagnosing Red Eye in Cats 

It's important to see a vet or veterinary ophthalmologist if your cat as a red eye. While the symptoms for different causes are very similar, our team at Northwest Animal Eye Specialists can run diagnostic tests to determine the specific eye condition causing the redness. 

We can also conduct a visual examination and may take fluid samples to test for pathogens. 

Treatment for Red Eye in Cats 

Once your veterinary ophthalmologist has determined the cause, they can develop a treatment plan that may include:

  • Medications such as antibiotics or other topical ointments such as eye drops to alleviate symptoms
  • Flushing the eyes with eyewash
  • Quarantining (for households with multiple cats, to keep the redness from spreading if your cat's eye condition is contagious)

Make sure to follow your vet's treatment recommendations and instructions carefully to avoid further eye injury or problems. 

Note: The advice provided in this post is intended for informational purposes and does not constitute medical or behavioral advice regarding pets. Please make an appointment with your vet for an accurate diagnosis of your pet's condition.

Do you suspect your cat or dog may be suffering from an eyelash disorder? Contact our Renton vets to book an appointment with our veterinary ophthalmologist.

New Patients Welcome By Referral

Northwest Animal Eye Specialists is accepting new patients! Our experienced vets are passionate about the eye health of animals. Talk to your vet today about getting a referral to our Renton or Kirkland clinics.

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