This book provides an integrated review of the human ocular microbiome. It documents the discovery of ocular surface microbes by the conventional cultivable method and next generation sequencing technologies in both healthy and diseased (keratitis, uveitis, endophthalmitis, blepharitis, conjunctivitis etc.) eyes. The book further discusses the confounding factors that influence the microbiome, mycobiome and virome. The chapters cover niche-specificity with reference to skin, eyelid- margin, hands etc. It highlights the concept of core genera, dysbiosis and discriminating genera and covers the functional relevance of the dysbiotic microbiome, mycobiome and virome with respect to ocular diseases. The book includes topics on the relevance of molecular mechanisms, including quorum-sensing and mucin metabolism to ocular disorders, such as dry eye; and, microbiome-based therapies for treating of ocular disorders like vernal keratoconjunctivitis.