Typical patterns of staining with fluorescein or rose bengal and their diagnostic importance. (A) Dendritiform staining (dichotomously branching lesions, often with terminally bulbous swellings)—typical of herpes simplex keratitis. (B) Staining in the interpalpebral zone of exposure in the dry eye (usually more so with rose bengal than with fluorescein) in keratoconjunctivitis sicca. (C) Linear punctate staining in the superior cornea (caused by a foreign body entrapped in the upper palpebral conjunctiva). (D) Corneal abrasion or erosion (gross epithelial defect), usually just below the center of the cornea. (E) Eyedrop-induced allergy or toxicity (staining on the inferonasal bulbar conjunctiva of the right eye), where drugs gravitate on their way to the lacrimal-outflow system.