Condition

Corneal Ulcer

Also known as Eye Ulcer, Cornea Ulcer, Microbial Keratitis, Corneal Sore, Infected Corneal Ulcer

Updated May 16, 2026For educational purposes only. Not a substitute for medical advice. See our terms.

Bottom Line

A corneal ulcer is an open sore on the clear front window of the eye. Pain, light sensitivity, a white spot, or blurry vision needs urgent eye care.

A corneal ulcer is a wound on the cornea with inflammation around it. Many ulcers are caused by infection, but severe dry eye, injury, and immune disease can also cause ulcers 1.

An infected ulcer is a form of infectious keratitis. It can scar the cornea or, in severe cases, thin it enough to perforate 2.

Contact lens wear is one of the most common risk factors. The first step is to stop lens wear and get a slit lamp exam 3.

Causes

A corneal ulcer can have more than one cause.

  • Bacteria. This is common in contact lens related ulcers.
  • Viruses. Herpes can cause repeat corneal sores.
  • Fungus. Plant or soil injuries can raise this risk.
  • Parasites. Water exposure in contact lenses can cause rare infections.
  • Severe dry eye. A dry surface can break down and fail to heal.
  • Immune disease. Some ulcers are inflammatory, not infectious.

Diagnosis can be difficult because many germs can cause microbial keratitis 1.

Treatment

Treatment is based on the ulcer cause, size, depth, and location.

  • Antibiotic drops. These treat many bacterial ulcers.
  • Antiviral or antifungal medicine. These are used when the germ is not bacterial.
  • Culture. A sample may be taken for large, central, or unusual ulcers.
  • Lubrication and protection. Severe dry eye ulcers may need bandage lenses or other surface support.
  • Surgery. Rare severe ulcers may need glue, amniotic membrane, or corneal transplant.

Contact lens related ulcers need prompt therapy and careful follow-up 3.

Prevention

You can lower ulcer risk with safer eye habits.

  • Never sleep in contact lenses unless your doctor prescribed overnight wear.
  • Keep lenses away from tap water, pools, lakes, and showers.
  • Use eye protection for yard work and tools.
  • Treat severe dry eye and eyelid disease early.
  • Do not use steroid eye drops unless an eye doctor prescribed them.
  • Replace contact lens cases and solution as directed.

Common Questions About Corneal Ulcers

Yes. A corneal ulcer can scar the clear cornea. Severe ulcers can thin or perforate the cornea.

Next Steps

  1. 1Seek urgent eye care today for eye pain with light sensitivity, blurry vision, or a white corneal spot.
  2. 2Remove contact lenses and bring the lenses, case, and solution to the visit.
  3. 3Use prescribed drops exactly on schedule if treatment starts.
  4. 4Keep close follow-up visits until the doctor says the ulcer is healing.
  5. 5Go to the emergency room for chemical splash, severe trauma, sudden vision loss, or red eye in a newborn.

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