Corneal Ulcer – Infectious Keratitis, What to Do and When It Is Urgent

The cornea is the clear window at the front of the eye. When bacteria, a fungus or a parasite gets into its tissue, an ulcer forms – in medical terms a corneal ulcer, or infectious keratitis. This is one of the urgent conditions in eye care: a small ulcer that is treated quickly usually heals well, but an ulcer that is treated late may leave a permanent scar that affects vision. This page explains how to recognize it, what causes it, and what happens during the examination and treatment.

The signs

• Eye pain that keeps getting worse – not just burning or itching.
• Redness, usually in one eye, and especially around the cornea.
• Strong sensitivity to light and tearing.
• Blurred vision that does not clear when you blink.
• A white or grayish spot on the cornea, which can sometimes be seen in a mirror.
• Discharge, watery or pus-like.

At first these signs resemble conjunctivitis, which is why it is not unusual for a corneal ulcer to be diagnosed late. The important difference: conjunctivitis causes discomfort, but no real pain and no drop in vision. Real pain, light sensitivity and blurring – together with a red eye – need to be examined the same day. For more on telling urgent from non-urgent problems, see Urgent eye problems.

What causes a corneal ulcer

The cornea is usually well protected. An ulcer forms when this protection is compromised:

• Contact lenses – the most common cause, especially sleeping in lenses, exposure to water or poor hygiene. Read more in Contact lens keratitis.
• Injury – a corneal abrasion or foreign body, and especially an injury from a branch, a plant or soil, which raises the risk of a fungal infection.
• A damaged eye surface – severe dry eye, an eyelid that does not close properly, eyelashes turning toward the eye, or reduced corneal sensation.
• Herpes – recurrent attacks of herpetic eye disease can cause corneal ulcers and also weaken the cornea against other infections.
• After eye surgery, and with long-term use of steroid drops without follow-up.
• General conditions – poorly controlled diabetes, a weakened immune system.

The types

Bacterial – the common type. It usually develops quickly, within hours to days, with pain and discharge.

Fungal – more common after an injury from plant material, in hot climates and with steroid use. It develops more slowly, but requires prolonged treatment.

Parasitic (Acanthamoeba) – rare, and linked mainly to contact lenses and exposure to water. The pain is especially severe relative to how the eye looks.

Viral – mainly herpes, which is treated in a completely different way.

The examination

During a slit-lamp examination, using a dye that highlights damage to the cornea, the ophthalmologist sees the size of the ulcer, its depth and its location, and checks whether there is also inflammation inside the eye. For a significant ulcer, one in the center of the cornea, or when a fungus or parasite is suspected, a tiny sample is taken from the ulcer for culture, to identify exactly what is causing it and which treatment will work. Contact lens wearers are asked to bring their lenses, case and solution.

Treatment

• Antibiotic drops for a bacterial infection – in the first few days sometimes every hour, including at night, and then at a decreasing frequency. Do not choose drops yourself: ordinary antibiotic eye drops used for conjunctivitis are not always suitable for a corneal ulcer.
• Antifungal or antiparasitic drops when that is the cause – usually for weeks or even months.
• Drops that dilate the pupil to ease the pain, and pain relievers as needed.
• Steroid drops – only in selected cases, only once the infection is under control, and only at the decision of an ophthalmologist and with follow-up.
• Close follow-up – in the first few days sometimes every day or two, to make sure the ulcer is shrinking and to change the treatment if it is not.

What not to do: do not wear contact lenses until you have fully recovered and your doctor approves, do not patch the eye without instructions, and do not use steroid drops or drops “left over at home” without an examination.

After recovery

A small ulcer at the edge of the cornea usually heals with a small scar that does not affect vision. An ulcer in the center of the cornea may leave a scar that blurs vision or causes irregular astigmatism. In such cases special rigid contact lenses sometimes improve vision, and when the scar is deep a corneal transplant is considered. In rare cases, when the ulcer becomes very deep, urgent surgical treatment is needed to save the eye.

When to seek care

• The same day: a red eye with real pain, light sensitivity or blurring – especially in contact lens wearers, after an injury from a plant or soil, or in anyone using steroid drops.
• Immediately, at the emergency room: a sharp drop in vision, severe pain, or a white spot that keeps growing.

Contact lens wearers with a red, painful eye: remove the lens immediately and do not put it back in until you have been examined.

An examination with Prof. Michael Mimouni

Prof. Michael Mimouni, Director of the Cornea Unit at Rambam, sees patients with diseases of the cornea and eye surface at his clinics in Herzliya Pituach and Haifa, including follow-up of corneal ulcers, scars after infection and vision rehabilitation. In an acute situation – severe pain or a drop in vision – go directly to an eye emergency room. For follow-up, a second opinion or evaluation of a scar after infection – get in touch to schedule an examination.

The information on this page is general and is not a substitute for an examination and personal medical advice. Diagnosis and treatment decisions are made only after a complete eye examination. With severe pain or a sudden drop in vision, seek an examination immediately.