Marginal ulcerative keratitis, also known as corneal ulcers, is overwhelmingly due to exogenous factors, i.e., inflammation that occurs when infectious causative agents invade the corneal epithelial cell layer from the outside. So, what are the clinical diagnosis of marginal ulcerative keratitis? The following will be introduced to you. Clinical diagnosis of marginal ulcerative keratitis 1, bacterial corneal ulcer: more common, is a serious purulent corneal ulcer. Commonly running corneal ulcers and Pseudomonas aeruginosa corneal ulcers. The former is often accompanied by anterior chamber pus also known as anterior chamber pus corneal ulcer. Mostly seen in the elderly, frail, malnutrition, chronic dacryocystitis patients. Often due to corneal trauma after Streptococcus pneumoniae, Mora Axenfeld bacillus, staphylococcus infection and disease. 2, viral corneal ulcers: common such as herpes simplex infection. There is often a history of fever before the onset of upper respiratory tract infection. Due to the widespread use of corticosteroids, viral infections are on the rise. Corneal epithelium at the beginning of the disease appeared dot-like vesicles, linear arrangement, later vesicles rupture and gradually connected into dendrites, the end of the nodular vesicles for dendritic keratitis. 3.Fungal corneal ulcer: It is caused by fungi directly invading into the cornea, mostly seen in the high temperature season. Common pathogenic bacteria for Fusarium, Aspergillus, Candida albicans and so on. The lesion is characterized by grayish white ulcer, dry surface, slight elevation, and pseudopods or small five-star foci can be formed around the ulcer, often accompanied by pus accumulation in the anterior chamber.