Scleritis: Refers to any inflammation of the sclera including episcleritis, a benign condition affecting only the episclera, which is generally short-lived and easily treated. Classic scleritis, on the other hand, affects deeper tissue and is characterized by higher rates of visual acuity loss and even mortality, particularly in necrotizing form. Its characteristic symptom is severe and general head pain. Scleritis has also been associated with systemic collagen disease. Etiology is unknown but is thought to involve a local immune response. Treatment is difficult and includes administration of anti-inflammatory and immunosuppressive agents such as corticosteroids. Inflammation of the sclera may also be secondary to inflammation of adjacent tissues, such as the conjunctiva.Sclera: The white, opaque, fibrous, outer tunic of the eyeball, covering it entirely excepting the segment covered anteriorly by the cornea. It is essentially avascular but contains apertures for vessels, lymphatics, and nerves. It receives the tendons of insertion of the extraocular muscles and at the corneoscleral junction contains the canal of Schlemm. (From Cline et al., Dictionary of Visual Science, 4th ed)Orbital Pseudotumor: A nonspecific tumor-like inflammatory lesion in the ORBIT of the eye. It is usually composed of mature LYMPHOCYTES; PLASMA CELLS; MACROPHAGES; LEUKOCYTES with varying degrees of FIBROSIS. Orbital pseudotumors are often associated with inflammation of the extraocular muscles (ORBITAL MYOSITIS) or inflammation of the lacrimal glands (DACRYOADENITIS).Scleral Diseases: General disorders of the sclera or white of the eye. They may include anatomic, embryologic, degenerative, or pigmentation defects.Pterygium: An abnormal triangular fold of membrane in the interpalpebral fissure, extending from the conjunctiva to the cornea, being immovably united to the cornea at its apex, firmly attached to the sclera throughout its middle portion, and merged with the conjunctiva at its base. (Dorland, 27th ed)Eye Diseases: Diseases affecting the eye.Choroiditis: Inflammation of the choroid.Eye Infections, Bacterial: Infections in the inner or external eye caused by microorganisms belonging to several families of bacteria. Some of the more common genera found are Haemophilus, Neisseria, Staphylococcus, Streptococcus, and Chlamydia.