Boots WebMD Partners in Health
Return To Boots

Eye health centre

Select a topic to explore more.
Select An Article

Corneal ulcer

A corneal ulcer is an open sore on the cornea, the thin clear structure overlying the iris - the coloured part of your eye.

Corneal ulcer causes

Most corneal ulcers are caused by infections

  • Bacterial infections cause corneal ulcers and are common in people who wear contact lenses.
  • Viral infections are also possible causes of corneal ulcers. Such viruses include the herpes simplex virus (the virus that causes cold sores) or the varicella zoster virus (the virus that causes chickenpox and shingles).
  • Fungal infections can cause corneal ulcers and may happen if you overuse eye drops that contain steroids.

Tiny tears to the cornea may also cause corneal ulcers. These tears can come from direct trauma, scratches or particles such as sand, glass or small pieces of metal. Such injuries damage the cornea and make it easier for bacteria to invade and cause a serious ulcer.

Disorders that cause dry eyes can leave your eye without the germ-fighting protection of tears and cause ulcers.

Disorders that affect the eyelid
and prevent your eye from closing completely, such as Bell’s palsy, can dry your cornea and make it more vulnerable to ulcers.

Chemical burns or other caustic (damaging) solution splashes can injure the cornea.

People who wear contact lenses
are at an increased risk of corneal ulcers. In fact your risk of corneal ulcerations increases ten times when using extended-wear soft contact lenses. Extended-wear contact lenses are those contact lenses that are worn for several days without removing them at night. Contact lenses can damage your cornea in several ways, including:

  • Scratches on the edge of your contact lens can scrape the cornea’s surface and make it more susceptible to bacterial infections.
  • Similarly tiny particles of dirt trapped underneath the contact lens can scratch the cornea.
  • Bacteria may be on the lens or in your cleaning solutions and can get trapped on the under-surface of the lens. If your lenses are left in your eyes for long periods of time, these bacteria can multiply and cause damage to the cornea.
  • Wearing lenses for extended periods of time can also block oxygen to the cornea, making it more susceptible to infections.

Corneal ulcer symptoms

  • Red eye
  • Severe pain
  • Feeling that something is in your eye
  • Tears
  • Pus or thick discharge draining from your eye
  • Blurry vision
  • Pain when looking at bright lights
  • Swollen eyelids
  • A white round spot on the cornea that is visible with the naked eye if the ulcer is very large

When to seek medical care

  • Change in vision
  • Severe pain
  • Feeling that there is something in your eye
  • Obvious discharge draining from your eye
  • History of scratches to the eye or exposure to chemicals or flying particles


Examinations and tests

Because corneal ulcers are a serious problem, you should see an ophthalmologist (a medical doctor who specialises in eye care and surgery) or an eye care professional.

  • The eye specialist will be able to detect if you have an ulcer by using a special eye microscope, known as a slit lamp. To make the ulcer easier to see, he or she will put a drop of the dye fluorescein into your eye.
  • If the specialist thinks that an infection is responsible for the ulcer, he or she may then get samples of the ulcer to send to the laboratory for identification.
Next Article:

WebMD Medical Reference

Popular Slideshows & Tools on Boots WebMD

woman looking at pregnancy test
Early pregnancy symptoms
humbug hard candies
Diarrhoea & more
donut on plate
The truth about sugar addiction
cute dog
10 common allergy triggers
couple watching sunset
How much do you know?
hand extinguishing cigarette
13 best tips to stop smoking
assorted spices
Pump up the flavour with spices
crossword puzzle
Help for the first hard days
bag of crisps
Food cravings that wreck your diet
adult man contemplating
Visual guide to BPH
polka dot dress on hangar
Lose weight without dieting