Bacterial keratitis is an infection of the cornea (the clear, round dome covering the eye's iris and pupil) that causes pain, reduced vision, light sensitivity and tearing or discharge from your eye. Resulting from infection from contact lens use or from injury to the eye, bacterial keratitis usually develops very quickly, and if left untreated, can cause blindness. The bacteria usually responsible for this type of keratitis infection are Staphylococcus Aureus and, for contact lens wearers, Pseudomonas Aeruginosa.