Cat Eye Infection – Causes, Symptoms and Treatment

cat eye infection
Image Pete Markham, Flickr

There are a number of causes of eye infections in cats, they can be caused by either a bacterial, virus or fungal infection. The type of infection relates to the part of the eye infected as well as the pathogen. Different parts of the eyeball and surrounding area can become infected or inflamed.

  • If the infection affects the conjunctiva, (the pink membrane which covers the front of the eyeball and the inside of the eyelids), it is known as conjunctivitis.
  • If the uvea (the pigmented vascular layer of the eye consisting of the iris,  choroid, and the ciliary body) is affected, the condition is known as uveitis.
  • Blepharitis refers to inflammation (or infection) of the eyelid.
  • A stye is caused by an infection of the sebaceous gland in the eyelid.
  • Keratitis is when the cornea is affected.

Eye infections can affect one (unilateral) or both eyes (bilateral). Infections may be on their own or as a result of a more systemic illness such as Feline Herpesvirus or calicivirus (both causes of cat flu). Conjunctivitis is the most common eye infection in cats. Injuries to the cornea resulting in scratches or ulcers can lead to an eye infection. Foreign objects such as a grass seed or an eyelash constantly rubbing on the surface damages the surface, which makes it more vulnerable to eye infections. It is also possible for a viral infection to be the primary cause of an eye infection, and as damage occurs for a secondary bacterial infection to take hold. Cats with weakened immune systems such as those with FIV are more prone to eye infections.

It is not uncommon for newborn kittens to develop eye infections early on. This may be due to the queen having a vaginal infection at the time of the birth or unclean surroundings. Kittens have very underdeveloped immune systems and are much more prone to developing infections than older cats. If you do have a litter of kittens, keep their surroundings clean and watch out for signs of infection.

In some cases, your cat may carry a viral infection (such as herpes) for the rest of his life and at times of stress, the virus will become re-activated, causing symptoms again.

Eye infections are serious and should be seen to quickly by a veterinarian, left untreated they can result in permanent blindness. Some types of eye infections, such as conjunctivitis are extremely contagious and can be spread from cat to cat.

What does the normal cat eye look like?

Healthy cat eyes

Before we go into symptoms of an eye infection, I will briefly outline what to look for in a normal cat eye.

  • A tiny bit of sleep in the corner of the eye is normal, but it should not be excessive.
  • The eye should be clear, with no signs of swelling in or surrounding the eye.
  • The pupils should be equal in size.
  • There should be no signs of cloudiness or swelling.

What are the symptoms of an eye infection in cats?

Severe eye infection in kitten
Image Kelbv, Flickr

One of the most common symptoms of an eye infection is discharge and/or swelling. The type of eye discharge can give your veterinarian an indication as to the type of infection your cat has. If the discharge is thick and mucousy, it is indicative of a bacterial infection. Clear discharge is more likely to be viral in nature.

Other symptoms may also be present depending on the cause.

  • Redness and swelling may occur around the outer eyelid, the third eyelid or the conjunctiva
  • Squinting
  • Excessive blinking
  • Raw, meaty appearance around the eye (this is a common sign of conjunctivitis)
  • Rubbing the eye
  • Discharge this may be thick, thin or watery
  • Pain
  • Excessive tearing
  • Crusting over the eyelid, which may, in turn, cause the upper and lower eyelids to become glued shut
  • Photosensitivity (aversion to bright light)
  • Change in appearance of the eye (cloudy colour)

How are eye infections in cats diagnosed?

Cat eye infection

Image courtesy Nottingham Vet School, Flickr

Your veterinarian will perform an examination of the and make a diagnosis based on symptoms. Is one eye or both eyes affected? Is there discharge, if so, what is it like, is there any pain, redness, what about accompanying symptoms?

He may need to perform other tests to determine the cause of the infection. This may include:

  • Culture- If there is discharge from the eye, your veterinarian may wish to perform a culture to determine the organism so that he can prescribe the most suitable type of antibiotic.
  • Fluorescein eye stain. A special orange dye is placed in the eye which will show up any foreign bodies or ulcers. 

  • Your veterinarian may also want to perform routine blood work to check for an underlying systemic disease.

  • If your cat is suffering from recurrent eye infections, your veterinarian may recommend a blood test for FIV.

What is the treatment for eye infections in cats?

Firstly, it needs to be said that you should never use medications for humans on cats, and that includes eye drops. If you suspect your cat has an eye infection, veterinary attention should be sought.

Treatment will depend on the cause and/or the location of the infection.

  • Antibiotic ointment or drops for bacterial eye infections.
  • Anti-fungal medications for fungal infections.
  • Most viral eye infections are self-limiting and will go away on their own, however, your veterinarian may choose to prescribe topical anti-viral cream or drops if the cause is viral.
  • Wipe away any discharge with a damp cotton wool ball. Discard immediately.
  • A warm compress to relieve discomfort.
  • Your cat may have to wear an Elizabethan collar during treatment to avoid rubbing/damaging the eye.
  • Always wash your own hands after treating a cat’s eyes, it is possible for some infections to be transmitted to humans.
  • Keep bedding and food bowls clean at all times.

In addition to treating the eye infection, supportive care will be necessary to help your cat overcome feline herpes virus. This includes intravenous fluids to treat dehydration and oral antibiotics for a secondary bacterial infection.

If you have other cats in the household, watch out for signs of eye infection in them.