DEAR MAYO CLINIC:

What is keratitis? Can it be cured?

ANSWER:

Keratitis, an infection of the eye's cornea, can be serious and, in severe cases, the infection may threaten vision. But with prompt treatment, keratitis can often be cured without any long-term complications.

The cornea is the clear, dome-shaped tissue on the front of the eye that covers the pupil and iris. A cornea may become infected by bacteria, viruses or fungi. Symptoms of keratitis include eye redness and pain, blurred vision, sensitivity to light, excess tears or other discharge from the eye, swelling, or an itchy, burning or gritty feeling in the eye.

A variety of factors can lead to keratitis. An injury, such as an object scratching the surface of the cornea or penetrating the cornea, may allow bacteria or fungus to get inside the cornea. Bacteria and fungi in water -- especially water in hot tubs, rivers, lakes and oceans -- may enter an eye when a person is swimming, causing the cornea to become infected. A member of the herpes virus family and the virus that causes chlamydia, among others, also may result in keratitis.

Wearing contact lenses can increase the risk of developing keratitis. Bacteria or fungi can inhabit the surface of a contact lens and contaminate the cornea when the lens is in the eye. The increased risk of keratitis for contact lens wearers typically comes from not disinfecting lenses properly, wearing contact lenses while swimming, wearing them longer than recommended, and not changing contact lens solutions regularly. Keratitis is more common in people who use extended-wear contacts (lenses that are left in overnight) than in persons who use daily wear contacts (lenses that are removed before sleeping).

Treatment of keratitis depends on the cause of the infection. For mild bacterial keratitis, antibacterial eyedrops may be all that is needed. For more severe cases, an oral antibiotic may be necessary. Keratitis caused by fungi usually requires antifungal eyedrops and oral antifungal medication.

Treating keratitis that's caused by a virus can be more challenging. In some cases, antiviral eyedrops and oral antiviral medications may effectively eliminate the symptoms. But medication may not be able to get rid of the virus completely, and viral keratitis may reoccur in the future.

Although keratitis usually can be cured, if treatment is delayed or if the infection is severe, the result may be a scar on the cornea that can interfere with eyesight. In that situation, a corneal transplant may be necessary to restore normal vision.

To decrease the risk of developing keratitis, people who wear contact lenses should wash their hands before handling the lenses. Also, the solution in the contact lens case should be discarded each time lenses are disinfected, or once a week if the lenses are stored without use. And the contact lens case should be replaced every three to six months. Contact lens wearers should carefully follow their eye care professional's instructions for taking care of lenses and replacing them according to the recommended schedule.

Those who notice any symptoms of keratitis, particularly eye redness, pain or decreased vision, should make an appointment to see an eye doctor right away. The sooner keratitis is treated, the better the chances for a quick and full recovery.

Amir Khan, M.D., Ophthalmology, Mayo Clinic, Rochester, Minn.

Medical Edge from Mayo Clinic is an educational resource and doesn't replace regular medical care.

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