Inflammation of a deep or shallow layer of the sclera, the thick white outer coating which covers most of the eyeball. Not usually viral or bacterial, it is generally the result of an allergic reaction to a disorder elsewhere, such as tuberculosis or certain rheumatic disorders. The cause is also often unknown and the condition is rare, although more common in men than women. The sclera consists largely of connective tissue. If the inflammation is located deep in the tissue, one or more firm swellings occur, but if the seat of infection is shallower, increased blood supply causes red to violet discoloration of the swelling. The swelling is painful, particularly if there is pressure on the eye. If scleritis is seated behind the eye, the eye bulges (exophthalmos), and is painful when moved. A squint may also occur as a result of irritation to the eye muscle. A possible complication is a thin spot in the sclera, which can bulge and take on a bluish tinge. Scars can also occur in the sclera. Treatment is usually with corticosteroids, but the inflammation can recur.