This is when an infection (bacterial, fungal, or viral) invades the cornea, the normally clear window that makes up the front of your eye. The cornea is unique because it is one of the few tissues in the eye that is clear, allowing us to see bacterial infections with no opaque skin blocking our view. Corneal ulcers usually look like a small white spot on the surface of the eye, though they are usually so small that they can only be seen using the slit lamp microscope. These infections can occur after a corneal abrasion, with contact lens use, and sometimes randomly with no obvious cause. Treatment is aggressive and involves antibiotic drops (often multiple antibiotics) to nip the infection in the bud as quickly as possible. Ulcers can be severe and penetrate all the way through the cornea and result in loss of the eye (very rare). Ulcers can also create scarring of the normally clear cornea. This scarring can limit the vision and necessitate a corneal transplant if severe enough.