The cornea is the transparent area at the front of the eyeball. A corneal ulcer is an erosion or open sore in the outer layer of the cornea. It is associated with infection.

See also: Corneal injury

Corneal ulcers are most commonly caused by an infection with bacteria, viruses, fungi or parasite. Other causes include:

• Abrasions (scratches)
• Foreign bodies in the eye
• Inadequate eyelid closure
• Severely dry eyes
• Svere allergic eye disease
• Various inflammatory disorders

Contact lens wear, especially soft contact lenses worn overnight, may cause a corneal ulcer. Herpes simplex keratitis is a serious viral infection. It may cause repeated attacks that are triggered by stress, exposure to sunlight, or any condition that impairs the immune system.

Fungal keratitis can occur after a corneal injury involving plant material, or in immunosuppressed people. Acanthamoeba keratitis occurs in contact lens users, especially those who attempt to make their own homemade cleaning solutions.

Risk factors are dry eyes, severe allergies, history of inflammatory disorders, contact lens wear, immunosuppression, trauma, and generalized infection.

• Eye burning, itching and discharge
• Eye pain
• Eye redness
• Impaired vision
• Sensitivity to light (photophobia)
• Watery eyes
• White patch on the cornea

• Examination of scrapings from the ulcer
• Fluorescein stain of the cornea
• Keratometry (measurement of the cornea)
• Pupillary reflex response
• Refraction test
• Slit-lamp examination
• Tear test
• Visual acuity

Blood tests to check for inflammatory disorders may also be needed.

Treating corneal ulcers and infections depends on the cause. They should be treated as soon as possible to prevent further injury to the cornea. Patients usually start treatment with antibiotic that is effective against many bacteria. More specific antibiotic, antiviral, or antifungal eye drops are prescribed as soon as the cause of the ulcer has been identified.

Corticosteroid eye drops may be used to reduce inflammation in certain conditions. Severe ulcers may need to be treated with corneal transplantation.

Untreated, a corneal ulcer or infection can permanently damage the cornea. Untreated corneal ulcers may also perforate the eye (cause holes), resulting in spread of the infection inside, increasing the risk of permanent visual problems.

• Loss of the eye
• Severe vision loss
• Scars on the cornear

Call your health care provider if you develop impaired vision, severe light sensitivity, or eye pain.

Prompt, early attention by an ophthalmologist for an eye infection may prevent ulcers from forming. Wash hands and pay very close attention to cleanliness while handling contact lenses. Avoid wearing contact lenses overnight.

Butler FK. The Eye in the Wilderness. In: Auerbach PS, ed. Wilderness Medicine. 5th ed. St. Louis, Mo: Mosby; 2007:chap 25.