Cornea: Window to ocular immunology

The ocular surface is continuously exposed to environmental agents such as allergens, pollutants, and microorganisms, which could provoke inflammation. However, an array of anatomical, physiological, and immunological features of the ocular surface conspire to limit corneal inflammation and endow the eye with immune privilege. A remarkable example of ocular immune privilege is the success of corneal allografts, which unlike all other forms of organ transplantation, survive without the use of systemic immunosuppressive drugs or MHC matching. This review describes the anatomical, physiological, and dynamic immunoregulatory processes that contribute to immune privilege.