A condition in which the thin layer of tissue that covers the sclera (the white part of the eye) becomes inflamed. The cause is usually not known, but it may occur with certain inflammatory conditions, such as lupus and rheumatoid arthritis. Signs and symptoms include redness, swelling, tenderness, mild pain in the eye, and sensitivity to light. Episcleritis usually does not affect vision and often goes away without treatment. Also called bulbar conjunctivitis.