Ask the Vet: See Veterinarian for Pet's Red or Cloudy Eye
Q: My cat was diagnosed with uveitis after I noticed that the iris of one eye had turned red, its pupil was small, and a foggy haze filled the normally clear front of the eye. My veterinarian prescribed steroid eye drops and sent a blood sample to the lab for further testing.
What is uveitis, and what causes it?
A: Uveitis is inflammation of the uvea (YOU'-vee-uh), the structures of the eye that are filled with blood vessels.
By weight, the eye has the highest blood flow of any organ in the body. Light focused through the lens onto the retina generates heat within the eye, and 90% of the blood flowing through the eyes cools them.
The uvea is comprised of the iris, the colored part of the eye you can see, and two additional structures you can't: the ciliary body, which produces the fluid that keeps the front of the eyeball clear and round, and the choroid, the layer of blood vessels between the retina and the white sclera.
Uveitis has many causes, including viral, bacterial, parasitic and other infections; an overactive immune system that targets the eye; ocular wounds, corneal ulcers and cataracts; and even cancer and diseases of other body systems.
Common infectious causes include feline infectious peritonitis, feline leukemia, feline immunodeficiency virus, Bartonella and Toxoplasma. In a recent study of 120 cats, the cause could not be determined in 40.8% of cases, despite thorough diagnostic workups.
The steroid drops your veterinarian prescribed should help minimize inflammation. Additional therapy is directed at controlling pain and treating the underlying cause, if one can be identified.
Inadequately treated uveitis can lead to blindness, so consider requesting a referral to a veterinary ophthalmologist. Follow your veterinarian's guidance, and return as recommended for continued care.
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