i know it is an eye complaint but how do people catch it?

Iritis is inflammation of the iris as the name suggests. It is more correctly called anterior uveitis. This is an autoimmune disease and not caused by infection, therefore it cannot be caught. The tendency to suffer from it is inherited and in some patients it is a manifestation of other more general diseases including rheumatoid arthritis, psoriasis and autoimmune bowel disease (Chrohn's or ulcerative colitis).

It is treated with local steroid drops. Unfortunately it has a high recurrence rate. i found a website for you its www,iritis.org it gives you all the information you need