Conjunctivitis is very common in domestic felines, and recognizing its symptoms is essential to determine its cause and apply the appropriate treatment. We explain how to take care of your cat’s eyes and avoid problems. Conjunctivitis is a common situation in our pets, especially in cats. 

conjunctivitis in cats

It is an inflammation of the conjunctiva in response to external or internal aggression of various kinds. Which can affect one of the eyes (unilateral) or both (bilateral), and depending on the speed of the onset of symptoms and its persistence over time, conjunctivitis can be acute or chronic. There is no sexual, age, or race preference in the appearance of feline conjunctivitis.

The feline eye

The eye of cats is similar in many ways to the human eye, but certain peculiarities make them much more effective for night vision and movement, beneficial when hunting. 

The cat’s eyeball consists of several parts, but the one that concerns us in this article is the conjunctiva. This semitransparent membrane covers the part of the eye that contacts the outside, from the end of the cornea (a transparent membrane, convex in shape, located in the frontal area of ​​the eye), up to the edge of the eyelids, on the inside, including the third eyelid or nictitating membrane. 

It has blood vessels, nerves, and mucin-secreting cells. In addition, the lacrimal glands secrete tears to keep the conjunctiva and cornea moist and clean.

Most common causes of feline conjunctivitis

It must be borne in mind that it is essential to determine the origin of feline conjunctivitis since it can be a mild affectation or a more severe disease manifestation. These are the most common causes of this type of eye problem in cats :

Feline herpesvirus (HVF-1)

Is a viral agent that causes upper respiratory symptoms. Kittens and young cats are more susceptible, and it is easily contagious. Once the virus has contacted the animal, it can become a carrier, suffer recurrent conjunctivitis and corneal ulcers, and even become infected with bacteria. This disease can be prevented with vaccination.


it is produced by the bacterium Chlamydophila felis. It generally produces only conjunctivitis, although, on occasions, it can also affect the upper respiratory tract. 

It is easily transmissible between cats, especially in communities. There are vaccines against this disease.

Other infectious agents: Mycoplasma haemofelis, Calicivirus, various bacteria, fungi.

Trauma and foreign bodies:

It is common for cats to damage the conjunctiva and cornea when they interact with other animals, hit and scratch, or while grooming themselves with their paws. Sometimes foreign bodies get inserted, such as a spike or broken nail.

Chemical agents:

Some substances can be hazardous if spilled on our cat’s eye, such as bleach or alcohol, among others.


Various substances present in the environment, topical medications, or foods can trigger eye discharge and feline conjunctivitis.

Ocular anatomical alterations: abnormalities in the shape of the eyelids, the growth of the eyelashes, or the disposition of the lacrimal glands and the drainage holes of the tears, can cause conjunctivitis in the cat in a secondary way.

conjunctivitis in cats


lymphoma. Other eye diseases of the cat: uveitis, glaucoma, keratoconjunctivitis.

Conjunctivitis Symptoms in Cats and Complications

The most characteristic sign of conjunctivitis in cats is hyperemia; that is, the increase in blood flow to the conjunctiva, which results in redness of the cat’s eye. Therefore, it should not be confused with the congestion of the vessels of the episclera (the “whites of the eyes”), thicker, with a straighter, and darker red, which is usually indicative of more severe processes the eyeball, like glaucoma.

Along with this, other symptoms of conjunctivitis appear :

  • Thus, sometimes the conjunctiva becomes edematous, giving the sensation of swelling; it is known as chemosis.
  • The ocular discharge is common in conjunctivitis and other eye diseases affecting cats and can be serosa (transparent), mucoid (semitransparent and denser), purulent (thick yellow or green), or mixed.
  • The inflammation itself and the accumulation of secretions often trigger an itching or itching sensation, which is manifested by scratching.

Possible complications of feline conjunctivitis

When conjunctivitis occurs, we must be cautious since cats could injure their nails, causing corneal ulcers. These are very annoying, even painful, and our cat may show signs of pain, closing its eyelids, protruding the third eyelid, or nictitating membrane (a small triangular-shaped portion that emerges at the angle of the eye) or, more subtly, showing more listless or hiding.

Since the origin of conjunctivitis of the pussy can lie in a disease that affects other organs, it is crucial to observe and remember other symptoms that your cat may have shown in recent weeks. For example, in the case of the feline herpes virus, there are other symptoms related to the involvement of the upper respiratory tract, such as a runny nose, sneezing, coughing, or dyspnea.