[An update on uveitis].

Uveitis occurs in 0.4% of the population. Anterior uveitis is the most common anatomical type of uveitis (50%). HLA-B27-associated acute anterior uveitis represent 50% of anterior uveitis. Sarcoidosis and Behçet disease are the systemic diseases most frequently associated with anterior uveitis. Toxoplasmosis is the most frequent cause of posterior uveitis. Although the emphasis regarding endogenous uveitis has now shifted towards immunological, if not autoimmune mechanisms, infection is still believed to play a role in the development of disease. The initiating events probably determine the site and type of pathological process within the eye since the perpetuation mechanisms seem to be similar, at least they are mediated by CD4 T lymphocytes. These findings form the basic for control of the inflammatory process by immunosuppressive agents or immunomodulators like ciclosporin A.