Ankylosing Spondylitis (AS) is a form of arthritis. It mainly affects the lower back. Other joints and other parts of the body are sometimes affected. Treatment includes regular exercise and anti-inflammatory medicines. The severity of AS varies from mild to severe. It is mild or moderate in most cases. About 8 in 10 people with AS remain fully independent or minimally disabled in the long term and are able to work full-time for the whole of a normal working life. One important point to remember - tell a doctor urgently if you have AS and develop a painful or red eye. An eye complication called uveitis can be serious but can be treated successfully if treatment is given promptly.