This document discusses bacterial corneal ulcers. The cornea is prone to infection due to its exposure, but is normally protected by tears. A bacterial corneal ulcer can develop if the protective mechanisms are compromised, there is a predisposing eye condition, immunity is lowered, or the organism is very virulent. Clinical signs of a bacterial corneal ulcer include pain, watering, photophobia, blurred vision, redness, swollen lids, blepharospasm, conjunctival congestion, and a well-established ulcer with yellowish-white color, overhanging margins, necrotic floor, and surrounding edema.