Tick-borne disease. Infection with Ehrlichia canis, Rickettsia rickettsii, and Borrelia burgdorferi can cause conjunctivitis, subconjunctival hemorrhage, anterior uveitis, posterior uveitis, chorioretinitis, retinal hemorrhage,
or optic neuritis. However, ocular signs are only found in 10% to 15% of naturally infected dogs.
Histoplasmosis. Ocular signs of this fungal disease include blepharitis, uveitis, chorioretinitis, granulomatous retinal detachment, and optic
Toxoplasmosis. Serologic testing indicates that up to 79% of cats with uveitis are seropositive for Toxoplasma gondii. However, there is a high Toxoplasma-positive prevalence in healthy, normal cats, and it's uncommon to find the organism in the uvea of a seropositive cat with
Uveodermatologic syndrome. This canine disease normally produces bilateral anterior and posterior uveitis, often accompanied by serous retinal detachment.
This disease only occurs in an eye with pigment, so it can be unilateral in dogs with one blue and one brown eye. Ocular disease
will often precede dermatologic signs of poliosis and vitiligo.
Infectious canine hepatitis. This immune-mediated disease caused by canine adenovirus has become rare since vaccination became routine. Infection or vaccination
can cause an interstitial keratitis and uveitis. Ocular signs begin about 10 to 14 days after vaccination. Owners may notice
blepharospasm, miosis, and photophobia. Within 24 to 48 hours of the onset of uveitis, corneal edema will develop. The corneal
edema can be focal or diffuse and has a ground glass appearance.
Ocular lesions associated with hypertension include optic nerve and retinal edema, retinal vessel tortuosity, retinal hemorrhage,
vitreal hemorrhage, hyphema, and retinal detachment. Retinal degeneration occurs secondary to ischemia and retinal inflammation.
Signs of metastatic neoplasia include conjunctivitis, uveitis, hyphema, and retinal edema. The most common secondary ocular
tumor in all domestic animals is lymphosarcoma. In fact, 25% of uveitis is due to neoplasia, and 78% of uveitis due to cancer
is lymphosarcoma. Hemangiosarcoma, adenocarcinoma, and transmissible venereal tumors have also been reported to metastasize
bilaterally to the anterior or posterior uvea.
Heather Kaese, DVM, MS, DACVIM, DACVO, Eye Care for Animals, Overland Park, Kansas.
To hear Dr. Kaese discuss cataract development and the associated complications, as well as treatment options, scan the QR
code above, or go to http://dvm360.com/CVC13Kaese.