It can be difficult to determine the cause of uveitis. Determining one, however, is necessary due to the potential threat to vision or the possibility of a more significant systemic disease.
The top three causes of uveitis fall into the broad categories of infectious, immunemediated, and neoplastic disease, however uveitis can also occur secondary to disease of the lens, or other metabolic, vascular, traumatic, toxic, or reflexive causes.
Common causes of uveitis in dogs and cats include auto-immune issues, trauma, high blood pressure, cataract formation, or secondary to systemic infection or cancer. It also may occur secondary to a corneal ulcer, known as reflex uveitis.
Finally, in approximately 50% of cases in dogs and cats, we are unable to find a specific underlying cause, and consider the uveitis to be idiopathic. This diagnosis is made by exclusion, meaning we have to rule out the other more serious causes first before reaching this diagnosis.