Blindness from untreated eye infections

Eye infections are a treatable condition in cats; however, severe eye infections and eye infections which are left untreated can cause permanent blindness in cats. As well as the risk of blindness, eye infections cause extreme discomfort and pain. It is therefore extremely important that cats with eye infections are given veterinary attention.

Conjunctivitis is the most commonly diagnosed eye infection in cats. This is where the infection leads to inflammation of the conjunctiva – the pink membrane that lines the inner surface of the eyelids and the outer surface of the eyeball (see picture). Left untreated, conjunctivitis can lead to eye damage, vision loss and blindness.

Eye infections can be caused by injuries to the eye, or foreign objects in the eye (eg, dirt, sand). Newborn kittens may develop eye infections due to vaginal infections of the mother at the time of birth, as well as being born into an unsanitary environment.

Viral or bacterial diseases can also lead to eye infections. Feline calicivirus is a highly contagious virus that is a cause of ‘cat flu’, and can lead to conjunctivitis in cats. Likewise, feline herpesvirus is also a highly contagious virus that can lead to conjunctivitis, as well as (less commonly), keratitis, which is the inflammation of the cornea (the transparent front part of the eye). Damage to the cornea as a result of keratitis can lead to blindness. Feline chlamydophilosis is a bacterial cause of conjunctivitis. Other viral infections, such as feline immunodeficiency virus, feline leukaemia virus, and feline infectious peritonitis, can lead to uveitis (inflammation of the uvea, the middle area of the eye including the iris), which can also result in blindness.

Signs of an eye infection

  • Ocular discharge (discharge from the eyes) ranging in colour from clear to green-yellow, which may dry to form a crust
  • Excessive production of tears
  • Swelling of the eye
  • Red swollen conjunctiva
  • Clouding of the cornea
  • Squinting - due to discomfort, but severe inflammation can also cause scarring and fusion of the eyelids to the eye, especially in kittens
  • Rubbing due to discomfort   


Eye infections are often treated with eye drops or ointment and usually respond well to treatment. Seek veterinary advice as soon as possible when any ocular changes are noted, to avoid further pain and reduce the risk of blindness occurring.