Uveitis consists of a group of diseases characterized by significant sight threatening intraocular inflammation primarily involving the uveal tract (iris, ciliary body, and choroid), although inflammation of adjacent tissues, such as retina, optic nerve, and vitreous humor also occurs.

Little is known about the pathogenesis of uveitis, but in cases of endogenous uveitis in which no link with an infectious agent can be identified, autoimmunity has been invoked as the cause. Many cases are often labelled as idiopathic, but in some it may be part of systemic disease process, such as sarcoidosis, multiple sclerosis, and Behçet’s disease, or associated with the HLA-B27 positive group of diseases. Infectious agents, such as the herpes group of viruses, toxoplasma gondii, mycobacterium tuberculosis, and treponema pallidum are also well-recognized causes.

Uveitis mainly occurs in the 20-50 year age group, and can affect one or both eyes. The incidence of uveitis varies from 14 to 52.4/100,000 with the overall prevalence around the world is up to 0.73%. A recent study found that the extrapolated 10-year incidence of uveitis was almost three times higher than that reported almost 40 years previously. Most uveitis patients present at an age where they are in the most active period of their working life. In about half the patients the age of onset is in the third or fourth decade of life. This age distribution makes uveitis a group of ocular diseases with an important socioeconomic impact.

Many cases will resolve rapidly, but a significant number of patients develop persistent disease with inflammatory damage to ocular structures resulting in severe visual impairment. The main causes of sight loss are cystoid macular edema, cataract, and glaucoma.

Approximately 5-20% of legal blindness in developed countries is due to uveitis, and it has been estimated that uveitis accounts for 10-15% of all cases of total blindness in the USA. Acute anterior uveitis is the commonest subtype and carries the best visual outcome, with a worse visual prognosis seen in patients with posterior uveitis and panuveitis.

In non-infectious causes, therapy is usually aimed at dampening down the immune response with corticosteroids being the first line treatment. In sight threatening disease immunosuppressive agents may need to be added to improve or preserve sight.