context: A corneal ulcer is an open sore on the cornea, the thin clear structure overlying the iris (the colored part of the eye). Most corneal ulcers are caused by infections. Bacterial infections cause corneal ulcers and are common in people who wear contact lenses. Viral infections are also possible causes of corneal ulcers. Such viruses include the herpes simplex virus (the virus that causes cold sores) or the varicella virus (the virus that causes chickenpox and shingles). Fungal infections are an unusual cause of corneal ulcers and may happen after injury with organic material such as branches or twigs. People who contract this type of infection nay have been treated with steroid eyedrops or are likely to be wearing contact lenses which are not properly disinfected. Tiny tears to the cornea may also cause corneal ulcers. These tears can come from direct trauma; scratches; or particles, such as sand, glass, or small pieces of steel. Such injuries damage the cornea and make it easier for bacteria to invade and cause a serious ulcer. Disorders that cause dry eyes can leave your eye without the germ-fighting protection of tears and cause ulcers. Disorders that affect the eyelid and prevent your eye from closing completely, such as Bell's palsy, can dry your cornea and make it more vulnerable to ulcers. Chemical burns or other caustic (damaging) solution splashes can injure the cornea. People who wear contact lenses are at an increased risk of corneal ulcers. In fact, your risk of corneal ulcerations increases tenfold when using extended-wear (overnight) soft contact lenses. Extended-wear contact lenses are those contact lenses that are worn for several days without removing them at night. Contact lenses can damage your cornea in many ways. Scratches on the edge of your contact lens can scrape the cornea's surface and make it more open to bacterial infections. Similarly, tiny particles of dirt trapped underneath the contact lens can scratch the cornea. Bacteria may be on the lens or in your cleaning solutions and, thus, get trapped on the undersurface of the lens. If your lenses are left in your eyes for long periods of time, these bacteria can multiply and cause damage to the cornea. Wearing lenses for extended periods of time can also block oxygen to the cornea, making it more susceptible to infections. Red eye Severe pain Feeling that something is in your eye Tears Pus or thick discharge draining from your eye Blurry vision Pain when looking at bright lights Swollen eyelids A white round spot on the cornea that is visible with the naked eye if the ulcer is very large Change in vision Severe pain Feeling that there is something in your eye Obvious discharge draining from your eye History of scratches to the eye or exposure to chemicals or flying particles Because corneal ulcers are a serious problem, you should see your ophthalmologist (a medical doctor who specializes in eye care and surgery). Your ophthalmologist will be able to detect if you have an ulcer by using a special eye microscope, known as a slit lamp. To make the ulcer easier to see, he or she will put a drop containing the dye fluorescein into your eye. If your ophthalmologist thinks that an infection is responsible for the ulcer, he or she may then get samples of the ulcer to send to the laboratory for identification. If you wear contact lenses, remove them immediately. Apply cool compresses to the affected eye. Do not touch or rub your eye with your fingers. Limit spread of infection by washing your hands often and drying them with a clean towel. Take over-the-counter pain medications, such as acetaminophen ( Tylenol) or ibuprofen ( Motrin). Your ophthalmologist will remove your contact lenses if you are wearing them. Your ophthalmologist will generally not place a patch over your eye if he or she suspects that you have a bacterial infection. Patching creates a warm dark environment that allows bacterial growth. Because bacterial infection is a common occurrence in corneal ulcers, your ophthalmologist will prescribe antibiotic eyedrops. If the infection appears very large, you may need to use these drops as often as 1 drop an hour. Oral pain medications will be prescribed to control the pain. Pain can also be controlled with special eyedrops that keep your pupil dilated. If the ulcer cannot be controlled with medications or if it threatens to perforate the cornea, you may require an emergency surgical procedure known as corneal transplant. If you do not need hospitalization, your ophthalmologist will prescribe eyedrops and pain medications for you to take regularly at home. You will need to follow up with your ophthalmologist daily until your ophthalmologist tells you differently. You should contact your ophthalmologist immediately if you experience symptoms, such as worsening vision, pain, or discharge. Seek medical attention from your ophthalmologist immediately for any eye symptoms. Even seemingly minor injuries to your cornea can lead to an ulcer and have devastating consequences. Wear eye protection when exposed to small particles that can enter your eye. If you have dry eyes or if your eyelids do not close completely, use artificial teardrops to keep your eyes lubricated. If you wear contact lenses, be extremely careful about the way you clean and wear your lenses. Always wash your hands before handling the lenses. Never use saliva to lubricate your lenses because your mouth contains bacteria that can harm your cornea. Remove your lenses from your eyes every evening and carefully clean them. Never use tap water to clean the lenses. Never sleep with your contact lenses in your eyes. Store the lenses in disinfecting solutions overnight. Remove your lenses whenever your eyes are irritated and leave them out until your eyes feel better. Regularly clean your contact lens case. Discard and replace the contact lenses at the interval specified by your doctor A corneal ulcer is a true emergency. Without treatment, the ulcer can spread to the rest of your eyeball, and you can become partially or completely blind in a very short period of time. Your cornea may also perforate, or you could develop scarring, cataracts, or glaucoma. With the proper treatment, corneal ulcers should improve within 2-3 weeks. If scars from previous corneal ulcers impair vision, a corneal transplant may be needed to restore normal vision. American Academy of Ophthalmology 655 Beach Street Box 7424 San Francisco, CA 94120 (415) 561-8500 American Academy of Ophthalmology corneal infection, open sore on the cornea, contact lenses, contact lens wearers, bacterial infections, corneal ulcer