The cornea is the clear window over the surface of the eye. It is the first barrier to infection and invasive microorganisms. The cornea has a barrier called the epithelium that is impervious to most infectious organisms. However, the corneal barrier may be violated by trauma, dryness, incomplete lid closure, or contact lenses. When this barrier is violated, there is a route for bacteria, fungi, and protozoa to enter the eye. Other times, the infection can be a virus such as Herpes Simplex. It does not require a violation of the epithelial layer. Ulcers tend to cause eye pain, a sensation that something is in the eye, light sensitivity (photophobia), and blurred vision. If the ulcer is large enough, it may be visualized as a white spot on the eye. The most common type of corneal ulcer is a bacterial ulcer. We are constantly exposed to bacteria, and they are usually in the normal eyelid. Most times they are harmless, but once the cornea is damaged, they may cause a problem. The organism will vary depending on the type of trauma, but can be variable. Contact lens wearers will often get infections with organisms such as pseudomonas whereas people with dry eye may be more likely to be infected with coagulase negative staph. Other types of corneal ulcers include fungal ulcers. These are most common in people with preexisting eye problems such as cornea transplants, prior surgery, and trauma with plant matter or dirt. These infections are often slower growing, but can be extremely difficult to treat. Many of these infections require treatment with medications that must be specially formulated. The last type of infection that I want to address is acanthamoeba keratitis. It is almost always in contact lens wearers or people with some type of water exposure. It is a type of protozoa. This is probably the most difficult to treat infection of the eye and requires a specially formulated medication made from a pool cleaner to treat. It often needs to be treated for months afterward and is frequently confused with herpes simplex keratitis. If you are in Georgetown, Round Rock, Austin, Temple or the central Texas area, and you are concerned that you may have a cornea ulcer or would like a second opinion with a cornea specialist, please call our office to schedule an appointment at 512-686-1224.