The cornea is clear and curved to allow light to be transmitted to the back portion of the eye. An ulcer of the cornea, like an ulcer on skin or stomach, is an erosion of tissue. Corneal ulcers come in a wide variety of forms, degrees of severity, underlying causes, and seriousness of the disease.
Therapy is, of course, dependent on the nature of the ulcer. Ulcers can be associated with bacterial, fungal, viral infections, dry eye, trauma, foreign body, exposure, auto immune, and degenerative processes to name a few. Bacterial ulcers tend to be the most devastating and severe in some cases, allowing the corneal tissues to melt. Aggressive medical therapy, and sometimes surgery, is required. Permanent loss of vision, or the eyeball itself, is certainty a real possibility. Medical and surgical therapy decisions are quite involved and beyond the scope of this information.