Diagnosis and classification of autoimmune uveitis.

Uveitis is the most common ophthalmological finding in the practice of rheumatology and clinical immunology. The condition is frequently idiopathic and defined by the inflammatory status of the uvea, the part of the middle eye that includes the iris, ciliary body and choroid. Anterior uveitis involves the iris and ciliary body, while the posterior form is limited to the retina and choroid. Both forms represent indications for an urgent evaluation by an ophthalmologist as untreated cases may cause blindness. Anterior uveitis is associated with the HLA-B27 allele and is a classification criterion for seronegative arthritis forms such as ankylosing spondylitis, psoriatic arthropathy, arthritis associated with Crohn's disease and ulcerative colitis, and reactive arthritis. Posterior uveitis is associated with Behcet's disease and HLA-B51. The clinical suspicion is raised by self-reported symptoms in the case of anterior involvement and floaters for posterior uveitis while the diagnosis, in the absence of established criteria, is made by an experienced ophthalmologist.