The pathophysiology of ocular allergy: A review

Allergic eye disease is an abnormal immune hypersensitivity response to allergens. It is characterized by IgE-mediated and/or T-lymphocyte-mediated immune hypersensitivity reactions that lead to an immune response, resulting in the clinical manifestations of ocular allergy. This review will focus on immunopathophysiology of the different types of allergic eye disease commonly encountered in the primary care setting. The objective is to provide the clinician with a considerable understanding of the immunopathogenesis of allergic eye disease. The primary focus of this review will be on the antibody- and cell-mediated immune hypersensitivity reactions relevant to allergic eye disease, the different phases of ocular allergic immune response and the histopathological manifestations of these commonly encountered ocular allergies. The basic concepts of immunology with emphasis on adaptive immunity and lymphocyte activation, as well as the components of the immune system that are relevant to ocular allergy will also be reviewed.