Exophthalmos, Enophthalmos, and Strabismus in Dogs
Exophthalmos, enophthalmos, and strabismus are all diseases which cause the dog’s eyeball to be abnormally positioned.
With exophthalmos, the dog’s eyeball protrudes, or bulges, from the orbit of the eye. This may be due to a space-occupying mass behind the eyeball. Enophthalmos, meanwhile, causes the eyeball to recess, or sink, into the skull. Lastly, strabismus is when an affected animal’s 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, and is more commonly referred to as “crossed eyes.”
The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the PetMD health library.
Symptoms and Types
The signs for each of these disease are as follows:
- General malaise
- Swollen eyelid
- “Cherry eye“
- Loss of vision
- Pockets of pus in or around the eye (orbital abscess)
- Discharge from the eyes that is watery (serous) 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
- Deviation of one or both eyes from the normal position
- Decreased functioning of the muscles surrounding the eye
Exophthalmos is generally due to a space-occupying mass located behind the eyeball. Strabismus, or “crossed eyes,” is usually caused by an imbalance of extraocular (outside of the eye) muscle tone. The Shar-pei is highly susceptible to this eye disease.
Some other factors that may lead to these eye diseases include:
- Bleeding within the eye
- Pockets of pus within the eye
- Inflamed eye tissue (bacterial or fungal in nature)
- Inflamed or swollen sac of mucous in the bone that surrounds the eye socket
- Inflammation in the muscles surrounding the eye(s)
- Arteriovenous fistula (when arteries join with veins, and a new, abnormal passage is formed); this is rare
- Dehydration (it affects the water content within the eyeball)
- Drooping eyelid
- Constricted pupils
- Collapsed globe
- Loss of volume in the eyeball (i.e., the eyeball is shrunked and usually non-functional)
- Horner’s Syndrome (a lack of nerve distribution to the eye and/or a loss in the supply of nerves)
- Restriction of eye muscle mobility from scar tissue (usually from previous trauma or inflammation)
- Abnormal crossing of visual fibers in the central nervous system
You will need to give a thorough history of your dog’s health, onset of symptoms, and possible incidents that might have preceded this condition. Your veterinarian will perform a thorough physical exam, examining the eyeballs, surrounding bone and muscle, and an inspection of your dog’s mouth for any abnormalities. X-ray imaging 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 product made of fluid, cell waste, and cells
A medical condition in which one or both of the eyes are deviated from one another
An in-depth examination of the properties of urine; used to determine the presence or absence of illness
A bundle of fibers that are used in the process of sending impulses through the body
Something that is related to the whole body and not just one particular part or organ
Something that becomes worse or life threatening as it spreads
The wasting away of certain tissues; a medical condition that occurs when tissues fail to grow.
Inducing death on an animal or putting them to sleep
General discomfort of the body
A localized infection, usually a lesion filled with pus. Can be large or small in size.
Something that contains mucus and/or pus