Cat eye diseases & infections

Updated November 21, 2016

Cats are prone to eye infections and diseases, and the older a cat gets the more susceptible he is. Cats who live indoors and who’re vaccinated against infectious eye diseases may have a better chance of staying optically healthy, but cats that roam outside and come in direct contact with their furry neighbours may bring home more than they bargained for. While cat eye infections are caused by viruses, fungus or bacteria, cat eye diseases can be hereditary or clinical in nature and, if left untreated, can ultimately cause your beloved feline to go blind.


Cat eye infections can be viral, bacterial, protozoal or fungal in nature. Feline herpes virus-1, feline infectious peritonitis (FIP), and feline leukaemia complex are all viral infections. Chlamydiosis is a bacterial infection, toxoplasmosis is a protozoal infection and cryptococcosis is a fungal infection. Cat eye diseases include cataracts, glaucoma, melanoma, feline panleukopenia and progressive retinal atrophy (PRA).

Indications of Infection

A cat suffering from eye infections may show signs of conjunctivitis—or pink eye—noticeable as a green, thick or cloudy discharge from the eye. Symptoms of cat eye infections include discharge or puss, redness and swelling, inflammation of the cornea or the inside lining of the eye, peripheral or sudden blindness, dilated pupils and those that don’t respond to light, detached or inflamed retinas, corneal ulcers, eyeballs stuck to the eyelid and dry eye.

Indications of Disease

Cats with cataracts will appear to have a whitish or opaque colour in the lens of their eyes. Their eyes may become red and inflamed, and they may show signs of blurry or lost vision. Cats with glaucoma may show signs of severe and chronic inflammation, enlarged eyes, sensitivity to light and blindness. Untreated hypertension may cause permanent eye damage and blindness. Melanoma is common among older cats in which the iris thickens and the cat’s eye changes colour. Progressive retinal atrophy is an inherited yet painless disease in which a cat gradually loses his sight.


The feline herpes virus-1, feline leukaemia complex and feline panleukopenia are caused by a virus and spread by direct contact with an infected cat. Cryptococcosis, a fungal infection, is contracted through the cat's environment. Cataracts may be genetic, can result from trauma or other abnormalities and can also lead to glaucoma. Glaucoma usually develops from other eye infections or diseases. Cats who suddenly go blind may have untreated hypertension, which may be evidenced by bloody eye chambers and dilated pupils.


Conjunctivitis is treated with medicated eye drops, while feline infectious peritonitis is treated with anti-inflammatory drugs. Chlamydiosis is treated with antibiotics such as tetracycline, toxoplasmosis is treated with clindamycine and cryptococcosis is treated with oral anti-fungal medications over a long period of time. There is no effective treatment for feline panleukopenia, as this disease is very contagious and can be fatal. An eye diseased from melanoma is surgically removed, and a surgical transplant can be done to replace an eye affected by cataracts. Early-stage glaucoma can be treated with certain medications, but severe cases may require surgery. There is no cure for progressive retinal atrophy.

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