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Corneal ulcer: symptoms, causes and why it is urgent

The cornea is the clear, dome-shaped window at the front of the eye. It focuses light, so it must stay clear for you to see well. A corneal ulcer is an open sore on the cornea, almost always caused by an infection. It is one of the most serious causes of a red eye, because within days it can scar the cornea or, in severe cases, make a hole through it. Corneal infections are an important cause of preventable sight loss in India, and early treatment makes a real difference.

What are the symptoms of a corneal ulcer?

• a red eye, often with the redness strongest around the edge of the cornea
• pain, from moderate to severe, or a strong feeling of something in the eye
• watering or discharge
• blurred or hazy vision
• pain or discomfort in bright light
• swollen eyelids
• a white or grey spot on the cornea, which you may see in a mirror

Symptoms usually affect one eye and get worse over hours or days. Unlike eye flu, a corneal ulcer usually hurts and blurs vision. Any red eye with pain and blurred vision needs an eye doctor the same day.

What causes corneal ulcers?

Bacteria

Bacterial ulcers often follow a scratch on the cornea or contact lens wear, particularly sleeping in lenses or poor lens hygiene. They can worsen within a day.

Fungi

Fungal ulcers are common in warm, humid countries like India, and are often linked to an injury with plant matter: a leaf, a paddy or sugarcane stalk, a coconut frond, a thorn or a twig. In Goa, people working in fields, gardens and coconut groves, especially in the monsoon, should take any scratch to the eye seriously. Fungal ulcers can start slowly and need long treatment.

Acanthamoeba

Acanthamoeba is a tiny organism found in tap water, wells, pools and the sea. It mostly affects contact lens wearers who swim or shower in their lenses, or rinse lenses or cases with water. The pain is often severe, and treatment can take months.

Viruses

The herpes simplex virus (the cold-sore virus) and the shingles virus can cause ulcers and inflammation of the cornea, which can come back. Steroid drops used without an eye doctor's advice can make a herpes infection of the cornea much worse.

Who is at risk?

• contact lens wearers, especially those who sleep in lenses or let lenses touch water
• anyone with a recent scratch or injury to the eye, particularly from plant matter
• people using steroid drops without an eye doctor's supervision, or home remedies in the eye
• people with severe dry eye, or eyelids that do not close fully
• people with diabetes or a weakened immune system
• people whose cornea has lost feeling, for example after shingles

What should I do if I think I have one?

1. If you wear contact lenses, take them out and do not put them back. Keep the lenses and the case and bring them with you, as they can help identify the germ.
2. Do not rub the eye, and do not keep it covered with a pad or bandage.
3. Do not use leftover, borrowed or chemist-bought drops, and especially not steroid drops.
4. Do not put home remedies in the eye.
5. See an eye doctor the same day. Emergency eye care at ReNew Vision is available 24 hours; call 072489 88039 on the way. See also 24-hour emergency eye care.

How is a corneal ulcer treated?

Corneal ulcer treatment is done at ReNew Vision. The eye doctor examines the cornea under the slit lamp microscope with a drop of yellow dye, which shows the size and depth of the ulcer. Often a tiny sample is gently taken from the surface of the ulcer, after numbing drops, to help identify the germ.

Treatment is with medicated eye drops chosen for the likely germ: antibiotic drops for bacteria, antifungal drops for fungi, and other drops for viruses or Acanthamoeba. At first the drops are usually needed many times a day, sometimes through the night, and the eye is checked often to make sure it is responding. Drops that ease pain by resting the focusing muscle of the eye may be added. Treatment can take weeks, and longer for fungal and Acanthamoeba ulcers.

Use every drop exactly as advised, and do not stop when the eye starts to feel better. If an ulcer is very deep, threatens to make a hole in the cornea or leaves a dense scar, surgery may be needed, in some cases a cornea transplant. Cornea transplant is not done at ReNew Vision; if you need it, the eye doctor explains why and refers you.

Will my vision recover?

That depends on the size, depth and position of the ulcer, the germ, and how early treatment starts. A small ulcer away from the centre of the cornea, treated early, may heal with little effect on sight. A larger or central ulcer can leave a scar that blurs vision. This is why early treatment matters so much. The eye doctor will tell you what to expect for your eye.

How can I prevent corneal ulcers?

• Follow the contact lens rules: wash your hands, never sleep in lenses unless they are prescribed for it, keep lenses away from water, and replace lenses and cases on time. See contact lenses: safe use.
• Wear protective glasses when cutting grass or branches, working in fields or gardens, or using tools.
• Have any scratch to the eye checked early, especially one from plant matter.
• Never use steroid drops unless an eye doctor has prescribed them and is checking your eye.
• Do not put home remedies in the eye.
• Get dry eye and eyelid problems treated; see dry eye treatment.

For other causes of a red eye, see eye flu: what to do or the red eye, dry eye and cornea page.

Questions patients ask

How is a corneal ulcer different from eye flu?

Eye flu usually affects both eyes, feels gritty rather than painful, and leaves vision normal. A corneal ulcer usually affects one eye, hurts, blurs vision, makes bright light painful and may show a white spot. A red eye with pain and blurring needs an eye doctor the same day.

How long does a corneal ulcer take to heal?

Small bacterial ulcers often heal within a few weeks; fungal and Acanthamoeba ulcers can take much longer. Keep using the drops exactly as advised, even when the eye feels better, and come to every check-up.

Can I wear contact lenses after a corneal ulcer?

Not until the eye doctor says the cornea has fully healed. Then use a new pair of lenses and a new case, review your lens habits, and ask whether daily disposable lenses would suit you better.

Is a corneal ulcer an emergency?

Yes. An infected ulcer can damage the cornea within days. Emergency eye care at ReNew Vision is available 24 hours, every day; call 072489 88039 and come in.

Can a corneal ulcer leave a scar?

It can, especially if the ulcer is large, deep or in the centre of the cornea. A scar away from the centre may hardly affect sight, while a central scar can blur vision. Starting treatment early gives the cornea more chance to heal with a small scar.

This page is general eye-health information, not personal medical advice. Your eye doctor advises you after examining your eyes.