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Eye Diseases in Cats: Exophthalmos, Enophthalmos and Strabismus

4 min read

Reviewed and updated for accuracy on March 25, 2019 by Dr. Hanie Elfenbein, DVM, PhD

 

If your cat has a swollen eyelid, “cherry eye,” pus around the eye or crossed eyes, they may be symptoms of one of three cat eye diseases—exophthalmos, enophthalmos and strabismus.

 

Exophthalmos, enophthalmos and strabismus are all eye diseases in cats in which the cat's eyeball is abnormally positioned.

 

With exophthalmos, the eyeball protrudes or bulges from the orbit of the eye. This may be due to a space-occupying mass behind the eyeball.

 

Enophthalmos causes the eyeball to recess or sink into the skull. This happens possibly because the eyeball itself has lost volume and is becoming smaller in size.

 

Strabismus, or “crossed eyes,” is when one eye appears to look off at a different angle, unable to focus in the same direction as the other eye. This can occur with one or both eyes. Strabismus is caused by an imbalance of extraocular (outside of the eye) muscle tone, or it may be caused by something decreasing the mobility of the muscles surrounding the eye. 

 

Symptoms and Types of Cat Eye Disease

 

The signs for each of these cat eye diseases are as follows:

 

Exophthalmos:

  • Swollen eyelid

  • Swelling around the eye

  • Cherry eye

  • Loss of vision

  • Pockets of pus in or around the eye (orbital abscess)

  • Discharge from the eyes that is watery (serous), bloody or mucous mixed with pus (mucopurulent)

  • Lagophthalmos (inability to close the eyelids completely)

  • Inflammation of the cornea (transparent coating of the eye) or surrounding tissue

  • Pain on opening the mouth

 

Enophthalmos:

  • Entropion eyelid (inverted eyelid)

  • "Cherry eye”

  • Inability to see the eye globe

  • Wasting of the muscle surrounding the eye (extraocular muscle atrophy)

 

Strabismus:

  • Deviation of one or both eyes from the normal position

  • Decreased functioning of the muscles surrounding the eye

 

Causes

 

Causes of these cat eye diseases include:

 

Exophthalmos

 

Exophthalmos is generally caused by a space-occupying mass located behind the eye globe, or a space-occupying mass near the eye, such as with a tooth root infection.

 

Other factors include:

  • Bleeding around or within the eye
  • Pockets of pus around or within the eye
  • Inflamed eye tissue
  • Inflammation in the muscles surrounding the eye(s)

 

Note that increased intraocular pressure (glaucoma) can look very similar to exophthalmos.

 

Enophthalmos

 

Conversely, a mass located in front of the eye may cause enophthalmos.

 

Other factors include:

  • Cancer

  • Dehydration (which affects the water content within the eyeball)

  • Collapsed globe due to trauma

  • Loss of volume in the eyeball (i.e., the eyeball is shrunk and usually nonfunctional)

  •  Horner’s Syndrome (a lack of nerve distribution to the eye and/or a loss in the supply of nerves)

 

Strabismus

 

Strabismus, or "crossed eyes," is usually caused by an imbalance of extraocular (outside of the eye) muscle tone. Many Siamese cats have congenital strabismus, meaning they are born with it. This is not a disease, and these cats can live an otherwise normal life.

 

Other factors include:

  • Genetics

  • Restriction of eye muscle mobility from scar tissue (usually from previous trauma or inflammation)

  • Abnormal crossing of visual fibers in the central nervous system

 

Diagnosis

 

You will need to give a thorough history of your pet's health, onset of symptoms and possible incidents that might have preceded this condition to your veterinarian.

 

Your veterinarian will perform a thorough physical exam, examining the eyeballs and surrounding bone and muscle, and looking inside your pet’s mouth for any abnormalities.

 

X-ray images of the skull will help to determine the exact location of any growths, pockets of fluid or abnormalities in the muscle or bone that might be contributing to the abnormal positioning of the eyeball.

 

Your veterinarian will also probably want to perform basic blood tests, including a chemical blood profile, a complete blood count, a urinalysis and an electrolyte panel, just to make sure there is no underlying systemic disease involved. A CT scan may be recommended for facial masses.

 

Treatment

 

  • Eyeball out of socket:  If the injury is very recent (within a few hours), it is possible to try and reposition the globe back into the orbit. However:

  • Abscess or inflammation of the eyeball is best treated with:

    • Surgery to drain the abscess

    • Collection of samples for bacterial culture and microscopic examination

    • Draining the abscess and hot packing may help relieve some of the remaining swelling. Cat antibiotics and anti-inflammatory prescription pet medication.

  • Cancer of the eye is usually treated surgically in order to remove all involved tissue.

    • If appropriate, chemotherapy or radiotherapy will be prescribed.

  • Swelling of the tissue around the eye may be treated medically with antibiotics and corticosteroids, and surgery if necessary.

  • Strabismus is not treated directly, but rather, treatment is aimed at reducing the cause of the nerve or muscle dysfunction.

 

Living and Management

 

Your veterinarian will schedule follow-up appointments dependent on your pet’s underlying diagnosis. For example, if your pet has an eye infection, your veterinarian will want to examine your pet at least weekly until signs of the disease have resolved.

 

If you see signs of any of these cat eye diseases returning, you will need to contact your veterinarian immediately to avoid permanent damage to the eye.

 

Featured Image: iStock.com/ArtMarie