ANTIBACTERIAL PROTECTION OF THE OCULAR SURFACE

The outer surface of the eye is constantly exposed to a wide array of microorganisms. To protect the integrity or the ocular surface and to retain corneal transparency, a number of defense mechanisms have evolv ed. This article discusses the host mechanisms of the eyelids, tears, cornea and conjunctiva. These host defense mechanisms are identified a s either a native, nonspecific defense or a specifically acquired immu nological defense requiring previous exposure to an antigen and the de velopment of specific immunity. Nonspecific components that protect th e eye include the eyelids, ocular surface epithelium, normal flora and tear proteins. Specifically acquired immunity in tears, cornea and co njunctiva involves the interaction of antigen-presenting cells, lympho cytes and humoral components of the immune system.