Issue Description An inflammatory condition of the cornea in
dogs. Other Names Chronic Superficial Keratitis, CSK, Uberreiter's Disease
Causes The cause of pannus is believed to be an
immune-mediated inflammation of the cornea that is made worse by
external factors. Exposure to ultraviolet radiation and environmental
pollution increases the severity of the condition. Dogs that live in
areas of extensive sunlight, especially at high elevations tend to
have the worst clinical signs. Pannus is not painful, but advanced
cases may lead to blindness. Pannus occurs only in dogs. Most affected
dogs are middle-aged, but the disease can develop in young adult dogs.
Breeds Affected Pannus is generally known as a German Shepherd
Dog eye disease but has also been seen in the Belgian Tervuren, Border
Collie, Greyhound, and Siberian Husky.
Symptoms Initially, redness, ocular discharge and brown
pigment may be seen in the conjunctiva (white tissue of the eye).
White infiltrates made up of inflammatory cells then invade the clear
cornea. Next blood vessels invade the cornea. Finally pink connective
tissue grows into the cornea and later becomes brown. In a small
number of cases, two other symptoms may occur either alone or
together. A thickening, redness, depigmentation and lumpiness of the
third eyelid may occur. This is called a plasmoma. The other condition
which may occur is chronic, erosive ulceration of the lower eyelid
near the inner and outer corners of the eye. Pannus is uncomfortable
to the dog. When treated adequately, your pet can be free of this
irritation even though the corneas may not clear up completely.
Diagnosis CSK is usually a bilateral progressive
condition. Signs include pigmentation and vascularization of the
cornea (extension of blood vessels onto the cornea). It is usually
first seen at the lateral (temporal) limbus (the junction between the
cornea and sclera), although it eventually can extend from any part of
the limbus to cover the entire cornea. Severe cases can cause
blindness. Although CSK is usually identifiable by the appearance of
the eye and the breed of the affected dog, cytology will reveal the
presence of lymphocytes and plasma cells.
Treatment Treatment of CSK is usually with topical
corticosteroids or topical cyclosporine, but any treatment only
controls and reduces the inflammation rather than providing a cure.
Other investigated treatments include pimecrolimus, a derivative of
ascomycin that interferes with T cell activation and inhibits the
production of inflammatory cytokines. Strontium-90 radiation therapy
is also used to treat CSK. Canine sunglasses have also been used to
help protect the eyes of dogs with CSK to prevent further damage from