Perturbations of the ocular surface microbiome and their effect on host immune function

Purpose of reviewCurrent literature describing the ocular surface microbiome and host immunity are reviewed alongside experiments studying perturbations of the microbiome to explore the hypothesis that disruption of a healthy microbiome may predispose the ocular surface to inflammation and infection.Recent findingsThe ocular surface of healthy subjects is colonized by stable, pauci-microbial communities that are tolerant to the host immune response and are dominated by the genera Corynebacterium, Propionibacterium, and Staphylococcus. In animal studies, commensal microbes on the ocular surface interact with toll-like receptors to regulate the immune system through immune cell and inflammatory cytokine production, promoting homeostasis and protecting against infection. Contact lens wear, lens wash solutions, and preserved topical medications can disrupt the native microbiome and alter the relative diversity and composition of microbes on the ocular surface.The ocular surface microbiome confers protection against pathogenic colonization and immune dysregulation. Disruption of this microbiome by exogenous factors may alter the resistance of the ocular surface to infection. Further study of the relationships between human ocular surface microbiome and the local immune response are needed.