Abstract The eye may be the target of allergic inflammation in a large number of systemic immunologic conditions. Ocular signs and symptoms can often be the most striking and disabling aspects of such diseases. The eye is also affected by several local conditions in which immunologic mechanisms are thought to play a significant role. Certain anatomic and physiologic features appear to endow the eye with a unique immunologic reactivity which has made this organ of special interest to allergists and immunologists.