The uvea is the portion of the eye that contains the iris, the ciliary body and the choroid. Uveitis or iritis is inflammation of this area. It is most commonly seen between the ages 20 to 50. It can be serious, causing permanent loss of vision. Uveitis may occur without any identified cause, but it is often caused by autoimmune diseases (rheumatoid arthritis, ankylosing spondylitis), inflammatory conditions (Crohn's disease, ulcerative colitis), trauma, and infections (toxoplasmosis, syphilis, tuberculosis).