American Medical Association Family Medical Guide - American Medical Association [732]
Corneal Ulcer
A corneal ulcer is an open sore or break in the surface of the cornea (the clear, protective covering at the front of the eye). In most cases, a corneal ulcer begins as a scratch or other injury to the cornea that becomes infected by a bacterium, virus, or fungus. An infection can also be spread from another part of the body, such as when a person with a cold sore (which is caused by the herpes simplex virus) touches his or her mouth and then touches his or her eyes. Conditions that interfere with normal lubrication of the eyes by tears—such as entropion (see page 1035), ectropion (see page 1035), or dry eye (see above)—or using extended-wear contact lenses can increase the risk of corneal ulcers. People whose eyes are exposed to a spray of particles, such as wood or metal shavings, are also at increased risk.
If a corneal ulcer is not treated promptly, a scar can form on the cornea and impair vision. An infected ulcer may perforate the cornea and allow the infection to enter the eyeball, causing blindness.
Corneal ulcer
A corneal ulcer is an open sore or break in the surface of the cornea caused by an infection. The ulcer may be visible as a whitish patch on the cornea.
Dendritic ulcer of the cornea
A dendritic ulcer of the cornea is caused by a herpes simplex infection and is usually not visible to the naked eye. Staining the eye with special fluorescent eyedrops reveals the ulcer’s branchlike structure.
Symptoms
The symptoms of a corneal ulcer usually include discomfort or pain in the eye, redness (see page 127), increased sensitivity to light, and impaired vision. The ulcer’s effect on vision depends on its size and location. If a corneal ulcer is caused by a bacterial infection, the ulcer may be visible as a whitish patch on the cornea. An ulcer produced by a herpes simplex virus infection (dendritic ulcer) is usually not visible to the naked eye.
Diagnosis and Treatment
A corneal ulcer is diagnosed by the symptoms and an examination of the eye. If the doctor suspects that a dendritic ulcer may be present on the cornea, he or she may place special fluorescent eyedrops in the eye that stain and reveal the ulcer to confirm the diagnosis.
To treat a corneal ulcer caused by a bacterial infection, doctors prescribe antibiotics, given as drops, ointment, tablets, or injections. For a corneal ulcer caused by a herpes simplex virus infection, doctors prescribe antiviral medication in eyedrops or in an ointment. Corneal ulcers caused by fungi are treated with eyedrops that contain antifungal medication.
If scarring from corneal ulcers severely impairs a person’s vision, a doctor may recommend a cornea transplant (see below), a surgical procedure in which the damaged cornea is removed and replaced with a healthy cornea from a donor. If an ulcer has perforated the cornea, immediate surgery is required to seal the hole and prevent the infection from entering the eyeball.
Cornea Transplants
A cornea transplant is a surgical procedure that is used to restore vision when the cornea has been permanently damaged as a result of injury, infection, disease, or degeneration. A surgeon performs a cornea transplant in a hospital operating room using either local or general anesthesia. The procedure lasts about 1 to 2 hours and does not usually require an overnight stay in the hospital.
To perform the transplant, a surgeon uses a special surgical instrument (called a trephine) that works like a cookie cutter to remove the central portion of the damaged cornea. He or she then places a clear cornea supplied by an organ donor into the opening in the damaged cornea and sews it into place with very fine thread. The stitches remain in the cornea for up to a year or longer, until the cornea has healed completely. You will need to wear a patch over the eye for a few days after surgery to keep it from moving and dislodging the stitches.
The ophthalmologist will examine your eye regularly to ensure that the cornea is healing properly.