Uveitis In Dogs - Seattle Animal Eye Clinic

ANIMAL EYE CLINIC INFORMATION SERIES!
Anatomy of the eye
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Uveitis in Dogs
The Uvea
The word “uveitis” means inflammation inside
the eye. The uvea is the middle layer of the eye.
It includes the iris, the ciliary body, and the
choroid. Inflammation of these structures can
result from many causes, and can result in damage
to structures inside the eye, potentially leading to
vision loss and discomfort.
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ANIMAL EYE CLINIC INFORMATION SERIES!
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WHAT IS UVEITIS?
Uveitis is inflammation of the inner middle layer of the eye. Inflammation can result from many
causes, and basically means swelling, redness, oozing. Just as a finger will swell, turn red, and become painful if struck by a hammer or becomes infected, the uvea
can swell, become red, and leak
protein, fluid, or white blood cells
when inflamed.
WHAT ARE THE CAUSES OF UVEITIS IN DOGS?
Uveitis can result from trauma (blunt or penetrating), various types of infection within the
eye, certain types of cancer, or due to autoimmunity.
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Trauma: Just as a finger swells and turns red when struck by a hammer, the layers
of the eye will swell & become inflamed when
subjected to trauma. This can be a blunt injury,
or some type of penetrating injury. Typically
the inflammation subsides on its own over time,
but permanent damage to the eye can result
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Infection: Inflammation is one way the
body fights infection. It allows the body to send
antibodies, white blood cells, and other diseasefighting molecules to the site of infection.
Uveitis can result from infections inside the eye
(bacterial, fungal, protozoal), or on the surface
of the eye (cornea).
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Cancer: Various types of cancer can result in uveitis. Solitary tumors inside an eye
will cause inflammation as they grow within the normal tissues. These can be primary tumors- i.e. started in the eye, or metastatic tumors- i.e. spread to the eye from some other
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place in the body. Cancer elsewhere in the body can also cause the immune system to attack the eye inappropriately- so called paraneoplastic uveitis.
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Autoimmunity: This is by far the most common type of uveitis in dogs. In this
situation the body’s immune system has become sensitized to uveal tissue- it regards these
normal intraocular structures as a dangerous foreign invader and attacks the uvea as if it
were a bacteria or virus. The cause of this sudden change is unknown. This is similar to
other autoimmune conditions like Lupus, Rheumatoid arthritis, etc...
Based upon the specific historical and ophthalmic findings in your pet, your doctor may
suggest various tests to help diagnose the specific type of uveitis.
WHAT HAPPENS WHEN THE UVEA IS INFLAMED?
In most cases active uveitis is uncomfortable. The eyes become bloodshot, dogs are lightsensitive, and vision can be affected by increased murkiness of the intraocular fluids. Inflammation can lead to permanent damage to structures within the eye as well. Damage to
the lens can lead to cataract formation. Damage to the drain inside
the eye can lead to increasing pressure as fluid is unable to exit normally (glaucoma). Fluid can leak
from the back wall of the eye separating the retina from the wall
(retinal detachment). Every time
the inflammation is active, additional damage is done, so keeping
uveitis controlled is very important
if vision and comfort are to be
maintained.
HOW IS UVEITIS TREATED?
When a specific cause is discovered, treatment includes specific therapy directed at that
cause. Fungal infection would be treated with antifungal medications, bacterial infection
with antibiotics. In addition to these specific therapies we would prescribe antiinflammatory medications. These might include corticosteroids like prednisone and dexamethasone
(drops and/or tablets depending on severity and part of the eye involved) and nonsteroidal
antiinflammatory medications (NSAIDs). Often we will treat with drops to dilate the pu!
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ANIMAL EYE CLINIC INFORMATION SERIES!
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pil, as much of the discomfort associated with uveitis results from spasm of the muscles
that constrict it. Dilation therefore improves comfort. In cases where the cause is autoimmunity, medications might also include more immunosuppressive therapies like oral cyclosporine to reduce the drive behind the immune system’s attack. Autoimmune uveitis
usually requires lifelong treatment to maintain control, although medications are usually
decreased over time to reduce potential side effects. Your ophthalmologist will discuss the
treatment options based upon your pet’s individual situation.
WILL MY PET LOSE VISION COMPLETELY?
This is possible- even with all available treatment. Your doctor will discuss the prognosis
for your pet based upon the stage of disease and treatments selected. It is important to
keep in mind that most blind dogs have an excellent quality of life as long as comfort is
maintained. Not only are they in a protected and loving environment, dogs use vision very
differently than humans with their other senses far more developed than ours. Sudden vision loss will take a longer period of adjustment than a gradual decline, but in either case
most owners report that their pets adapt remarkably well.
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