The Riddle of Uveitis.

INFLAMMATION of the uveal tract, which comprises the iris, ciliary body and choroid, is the cause in 8.3% of cases of blindness in the fourth decade of life and in 2.5% of all cases of blindness in Britain (Sorsby 1956). In other words, about 2,500 of the 100,000 registered blind people in this country were blinded by uveitis and its complications, and this was particularly so in young people in the 30-40 decade. It is traditional to subdivide uveitis into anterior uveitis (or iridocyclitis) and posterior uveitis (or choroiditis), but it is only convenient to retain this concept if it can contribute a better understanding of the causes or mechanisms of the inflammatory process. It should nevertheless be remembered that it is an artificial distinction since the iris-ciliarybody-choroid is a continuous structure, derived from the mesoderm surrounding the optic cup, and this uveal tract is extremely vascular. It would indeed be surprising if inflammation of the anterior part did not affect the posterior part and vice-versa.