Corneal Ulcers: Why They Are an Emergency

What a corneal ulcer is

The cornea's surface epithelium is a barrier against infection. When it is breached (by a contact lens, a scratch, a foreign body, or the dryness and exposure of a poorly closing eyelid), bacteria, fungi, viruses or amoebae can invade the stroma beneath. The infection destroys tissue, the eye mounts an intense inflammatory response, and the result is an ulcer: an excavated, infiltrated area of cornea that is white against the clear tissue around it. Left untreated it can perforate the cornea.

Who is at risk

• Contact lens wearers, particularly those who sleep in lenses, swim or shower in them, or use tap water on them; this is the largest group
• People with a corneal injury or foreign body, including from gardening and agricultural work, where fungal infection is more likely
• Patients with dry eye, eyelid disease, incomplete lid closure or a cornea with reduced sensation
• Patients using steroid drops, or with a weakened immune system
• Patients with a history of herpes simplex or zoster eye disease

Symptoms

Pain that is often severe and out of proportion to the appearance, redness, marked light sensitivity, watering, discharge, blurred vision and a foreign body feeling. A white or gray spot may be visible on the cornea in the mirror. Any of these in a contact lens wearer means removing the lens and calling the same day.

Diagnosis and treatment

The ulcer is examined at the slit lamp, its size and depth are measured and photographed, and it is scraped for cultures to identify the organism. Treatment starts immediately, before the cultures are back: fortified antibiotic drops, often every hour around the clock for the first day or two, with antifungal or anti-amoebic drops added if the history suggests them. Contact lenses are stopped. The ulcer is reviewed daily until it is clearly improving, then less often. Steroid drops may be added later, under close supervision, to limit scarring once the infection is controlled. Healing takes days to weeks, and a scar is common; its effect on vision depends on its position.

Afterward

Once healed, vision is assessed. A central scar that blurs vision may be managed with a specialty contact lens or, rarely, surgery. Contact lens wearers are counseled on hygiene and lens type before returning to lenses, and some are advised toward daily disposables or toward vision correction surgery that removes the need for lenses altogether.