Virologic and immunopathologic aspects of eye diseases are being studied by the identification of immunoregulatory systems in vision and ocular disease and by the evaluation of the involvement of viruses in the etiology and pathogenesis of eye diseases. Regulatory mechanisms in disease are being investigated by concentrating on the interactions among lymphokines (interferon (IFN), interleukin 2), cell surface proteins (HLA-DR, Ia) and selected cells within the eye (retinal pigment epithelial (RPE) cell, photoreceptors, endothelial cells). These studies have identified alterations in the IFN system and class II antigens in retinal degenerations, inflammatory eye diseases and in selected immunologically mediated diseases (Acquired Immunodeficiency Syndrome (AIDS), autoimmunity). Studies are in progress to develop monoclonal antibodies to identify retinal cells (RPE). Since the RPE cell is an important regulatory cell in the retina, the interactions among lymphokines, class II antigens and RPE cell function are being evaluated. The role of viruses in the etiology and pathogenesis of eye diseases in man and animals is being studied. Attempts to identify viruses in tissues from patients with uveitis and acute retinal necrosis are in progress.