CORNEAL ULCER(microbial keratitis) The term keratitis / microbial keratitis are used to describe all suppurative infections of the cornea.They are characterized by the presence of white or yellowish infiltrates in the corneal storma, with or without overlaying corneal epithelial defect and it’s associated with signs of inflammation. The cornea has certain defensive mechanisms required because of it’s constant exposure to microbes and environmental influences: Reflex eye closing Flushing effect of tear fluid Epithelium can regenerate quickly and completely . Any breach in any of these mechanisms may result in certain pathogens succeeding in breaching the corneal defenses through superficial injuries or minor epithelial defects, then the bradytrophic corneal tissue will respond to the specific pathogen with a characteristic keratitis. PATHOGENESIS OF CORNEAL ULCER Corneal ulcers may be caused by : Viruses Bacteria Acanthoamoeba Fungi Once the bradytophic co