Corneal Ulcer

Medically Reviewed by Dany Paul Baby, MD on February 28, 2023
6 min read

A corneal ulcer is an open sore on your cornea. That's the thin, clear layer over your iris (the colored part of the eye). It’s also known as keratitis.

A corneal ulcer can cause:

  • Redness
  • Severe pain
  • The feeling that something is in your eye
  • Tears
  • Pus or thick discharge from your eye
  • Blurry vision
  • Pain when looking at bright lights
  • Swollen eyelids
  • A round white spot on your cornea

Talk to your doctor right away if you notice:

  • Vision changes
  • Severe pain
  • Discharge from your eye

It’s especially important to watch for problems if you’ve scratched your cornea before or if you’ve been around chemicals or small particles such as sand, metal, or glass.

Infections cause most corneal ulcers.

  • Bacterial infections
  • Viral infections such as the herpes simplex virus (which causes cold sores) or varicella virus (which causes chickenpox and shingles).
  • Fungal infections such as Fusarium, Aspergillus, or Candida, possibly after an injury by something natural such as a branch or twig. These infections are rare.
  • Parasitic infections with Acanthamoebaan amoeba found in fresh water and dirt.

People who wear contact lenses are more likely to get corneal ulcers. This risk is 10 times higher if you use extended-wear (overnight) soft contacts.

Bacteria on the lens or in your cleaning solution could get trapped under the lens. Wearing lenses for long periods can also block oxygen to your cornea, increasing the chances of infection.

Scratches on the edge of your contact might scrape your cornea and leave it more open to bacterial infections. Tiny particles of dirt trapped under the contact could also scratch your cornea.

Other things that may lead to a corneal ulcer include:

  • Steroid eye drops
  • Disorders that cause dry eyes
  • Eyelid inflammation (blepharitis)
  • Eyelashes that grow inward
  • Eyelids that turn inward
  • Conditions that affect your eyelid and keep it from closing all the way, such as Bell’s palsy
  • Chemical burns or other cornea injuries
  • Severe allergic eye disease

More causes of cornea injury include:

  • Chemical irritation
  • An object in the eye, such as sand or dust
  • Something striking the eye, such as a tree branch
  • Radiation injury from the sun, sun lamps, welding, or sun reflected on snow (snow blindness)
  • Complications of contact lens wear

cornea erosion can occur when the abrasion re-tears. Corneal infection, also called keratitis, is relatively rare. Several conditions can cause an infection of the cornea, including:

Conjunctivitis (pinkeye). Bacteria, viruses, or allergies can cause conjunctivitis. The condition usually causes only minor eye irritation. However, if it becomes severe or remains untreated, it can lead to corneal infection.

Herpes zoster (shingles). This infection is caused by the same virus that causes chickenpox. In some people, the infection becomes active again later in life, causing a painful, blistering rash called shingles. Shingles that develop on the face, head, or neck can also affect the cornea. About 40%-60% of people who get shingles in those areas will develop it on the cornea.

Ocular herpes. Herpes of the eye is caused by the herpes simplex virus—the same virus that causes oral and genital herpes. Ocular herpes develops on the eyelid or surface of the eye and can lead to corneal inflammation. This virus is the most common eye infection that causes blindness in the U.S.

Corneal dystrophies. Are somewhat rare conditions that cause changes to the cornea. There are more than 20 types. These eye problems are inherited, so if someone in your family has one of these eye conditions, you may be at risk. Corneal dystrophies usually affect both eyes and can cause vision loss and blindness. Sometimes, they cause no symptoms and are only discovered during an eye exam. Here are a few of the more common types of corneal dystrophies:

Fuchs' dystrophy. This progresses slowly, usually affecting people in their 50s and 60s. The condition damages the endothelial cells in the cornea. Symptoms include swelling and blistering of the cornea, blurred vision, pain, and vision problems.

Map-dot-fingerprint dystrophy. This causes small gaps between the outer layer and rest of the cornea, called epithelial erosions. These gaps cause blurred vision, pain, sensitivity to glare and light, and other symptoms that often flare up between ages 40 and 70 years.

Keratoconus. It's a progressive thinning of the cornea that affects 1 in 500 to 2,000 people in the U.S., usually in their teens and 20s, but it can occur in nearly every decade of life. With keratoconus, the cornea becomes thin and bulges outward in a cone shape, like a hernia. The condition can cause moderate to severe blurred vision, multiple images, glare, and halos around objects at night and rob people of the ability to lead a normal life. Often nearsightedness and astigmatism develop from keratoconus.

See your eye doctor right away. They’ll use a drop of dye and a special microscope called a slit lamp to look for problems.

If your doctor thinks you have an infection, they may take a small sample from the ulcer for analysis in a lab. This can help them decide on the best treatment.


Depending on the cause of your ulcer, you’ll probably get antibiotic, antiviral, or antifungal eye drops. You might need to use these as often as once an hour for several days.

To treat pain, your doctor may also give you oral painkillers or drops to widen (dilate) your pupil.


If medications don’t help or if the ulcer is severe, you might need a corneal transplant. Your doctor takes out your cornea and replaces it with a healthy one from another person.

Treatment Follow-Up

You’ll need to see your doctor every day until they tell you to stop. Call them right away if your symptoms get worse, such as blurry vision, pain, or discharge.

Your doctor may also recommend some steps you can take at home to ease symptoms:

  • Put cool compresses on your eye. But be very careful to keep water away from your eye.
  • Don’t touch or rub your eye with your fingers.
  • Limit the spread of infection by washing your hands often and drying them with a clean towel.
  • Take over-the-counter pain medications such as acetaminophen or ibuprofen.

If you have any eye problems, see your doctor as soon as possible. Even minor injuries can lead to an ulcer.

Wear eye protection when you’re around small particles.

If you have dry eyes or if your eyelids don’t close all the way, use artificial tears to keep your eyes moist.

If you wear contact lenses, be very careful about how you clean and wear them.

  • Always wash and dry your hands before handling lenses. Never use saliva to wet your lenses, because your mouth has bacteria that can hurt your cornea.
  • Take out your lenses every evening. Carefully clean them with solution, not tap water.
  • Never sleep with your contacts in.
  • Store the lenses overnight in disinfecting solution.
  • Take out your lenses whenever your eyes are irritated. Don’t put them back in until your eyes feel better.
  • Regularly clean your lens case.
  • Follow your doctor’s instructions on when to throw out and replace your contacts.

A corneal ulcer is a medical emergency. Without treatment, it might spread to the rest of your eye, and you could lose some or all of your eyesight in a short time. You can also get a hole in your cornea, scarring, cataracts, or glaucoma.

With treatment, most corneal ulcers get better in 2 or 3 weeks.

If you have trouble seeing because of scars from a corneal ulcer, you might need a corneal transplant.