Retinal vasculitis: Inflammation of the tiny blood vessels of the retina. Retinal vasculitis ranges in severity from mild to severe. Damage to the blood vessels of the retina can cause minimal, partial, or even complete blindness. Retinal vasculitis by itself is painless, but many of the diseases that cause it can also cause painful inflammation elsewhere, such as in the joints. Signs of retinal vasculitis can be observed by a physician using an ophthalmoscope. Further definition of the blood vessel condition can be determined with a special X-ray dye test (angiogram) of the retina. Diseases that cause retinal vasculitis include Behcet's syndrome, systemic lupus erythematosus, antiphospholipid antibody syndrome, systemic necrotizing vasculitis, Wegener's granulomatosus, Takayasu's vasculitis, and giant cell arteritis. Treatment typically involves use of high doses of cortisone-related medications, such as prednisone. In addition, some related diseases require immunosuppression with medication, such as cyclosporine, chlorambucil, and cyclophosphamide.