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Corneal ulcers

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A corneal ulcer will make the affected eye red and painful. They are particularly common in people who wear contact lenses. You should seek prompt medical treatment if you think you might have a corneal ulcer. Left untreated, corneal ulcers can damage your sight.

What are corneal ulcers?

A corneal ulcer is an open sore on the cornea, which is the clear dome that covers the coloured iris in the eye.

Corneal ulcers are often caused by infection. This includes, for example, when infection follows a physical injury to the cornea.

Injuries that seem minor can cause corneal ulcers, and you should seek medical attention promptly if you have an eye injury. Without proper treatment, a corneal ulcer might develop scarring that impairs your vision, or even leads to cataracts or glaucoma.

Illustration showing a cross section of an eye.
Cross-section of the eye, showing the cornea at the front.

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What are the symptoms of corneal ulcers?

A corneal ulcer might make your affected eye:

  • red and irritated
  • painful
  • feel like it has something in it
  • discharge tears or pus
  • have blurry vision
  • sensitive to bright light

You should see your ophthalmologist (medical eye specialist) or doctor if you have these symptoms, and over-the-counter eye drops do not cause improvement within 1 day.

Immediate medical treatment for a corneal ulcer lessens the chance of long-term damage to your vision.

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What causes corneal ulcers?

Corneal ulcers are usually caused by bacterial infection (inflammation of the cornea is also known as bacterial keratitis). They can also be caused by viral or fungal infection, or trauma.

Infections are more common if you:

  • wear contact lenses, especially overnight
  • have dry eyes
  • have had corneal damage or eyelid surgery in the past
  • have an underactive immune system
  • have certain eye allergies

An ulcer can also be caused by damage to the cornea from a foreign object or small particle.

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How are corneal ulcers diagnosed?

A large ulcer can be seen as a white spot on the cornea, but some ulcers can only be seen with closer investigation.

Your doctor or ophthalmologist will probably check your vision and examine the cornea using a special lamp. They might drop a small amount of dye into your eye to make any ulcer show up more clearly.

To work out what has caused any underlying infection, the ophthalmologist might take a sample scraping from the ulcer for analysis.

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How are corneal ulcers treated?

If the ulcer was caused by a foreign body in the eye, your doctor will first remove the object.

Corneal ulcers are usually treated with antibiotics, often given as eye drops. If your ulcer was caused by dirt, you might be given an anti-fungal medication.

If you wear contact lenses and have a corneal ulcer, you should take the lenses out straight away. Avoid rubbing your eyes, and wash your hands to stop any infection spreading. A cool compress can give some relief, as can over-the-counter pain relief medicine.

Corneal ulcers often improve after 2 or 3 weeks of treatment. An ulcer in the centre of the eye might take longer.

If the ulcer fails to heal, or leaves significant scarring of the cornea, your ophthalmologist might recommend cornea transplant surgery.

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Can corneal ulcers be prevented?

You can help prevent corneal ulcers by taking care of your eyes, and by seeing your doctor promptly if your eyes seem infected or have something in them.

If you wear contact lenses, you can help prevent corneal ulcers by:

  • cleaning and storing the lenses carefully
  • not wearing them longer than you should
  • avoiding wearing contact lenses overnight

If you have dry eye syndrome, or your lids do not close completely, keep your eyes moist with tear-substitute eye drops.

Wear goggles to protect your eyes from particles — for example, when you are gardening or using power tools.

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Last reviewed: May 2019

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