Eye Health Central

What is a Corneal Ulcer?

What is a Corneal Ulcer

Corneal ulcer

A corneal ulcer, known medically as ulcerative keratitis, is an inflammation or infection of the cornea, the clear layer covering your iris - the coloured part of your eye. They are quite common, especially in people who work outdoors, live in humid climates or wear contact lenses. They can be rather painful, and cause severe redness, discharge, and reduced vision.

What Causes Corneal Ulcers

The most common cause of corneal ulcers is a bacterial infection on the surface of the eye, but this is not the only cause

  • Bacterial Infection - Bacteria can enter the eye resulting from and injury, eye surgery, poor contact lens wear, immune deficiencies etc. According to a recent study, eighty percent of bacterial corneal ulcers are caused by Staphylococcus aureus, Streptococcus pneumoniae and Pseudomonas species. 
  • Viral Infections -  These can be caused by the herpes simplex virus (cold sores, chicken pox or shingles)
  • Fungal Infections - Eye Injuries such as a cut to the eye for example from a branch can cause fungal infections that may lead to a corneal ulcer
  • Dry Eye Syndrome - If the eye is not lubricated enough the epithelial cells on the surface of the eye can be damaged
  • Contact Lens Wear - Wearing contact lenses can increase the risk of corneal ulcers if the wearer does not follow the advice given by their optometrist- it is important to keep contact lenses and their cases clean, not to overwear them and not to swim or sleep in them. All of these practices are to prevent the risk of bacterial infections

Signs and Symptoms Of A Corneal Ulcer

  • Eye Pain or Discomfort
  • Redness of the eye or inflammation
  • Sensitivity to light
  • Blurred vision
  • Discharge from the eye
  • White or grey spot on the cornea

A corneal ulcer can be serious and should not go untreated, if you experience any of these signs you should see your optometrist or doctor as soon as possible.

Does Wearing Contact Lenses Cause Corneal Ulcers

Wearing contact lenses does not cause corneal ulcers if you follow the cleaning and wearing guidelines provided by your optometrist.

Contact lens wearers who do not wear their contacts as instructed are more susceptible to corneal ulcers. This includes wearing lenses longer than advised, not cleaning them before each application, not replacing them frequently enough, or wearing them while swimming, bathing or sleeping. Any one of these actions increases the risk of introducing either foreign debris or micro-organisms to the surface of the eye, which can then cause damage and bacterial infection.

Contact lenses and Corneal Ulcers

According to Moorfields Eye Hospital, there are some basic rules for contact lenses to help reduce their risk of corneal ulcers


  • Always wash, rinse, and dry your hands thoroughly before handling your lenses
  • Always clean your lenses as advised by your optometrist, keep the container clean and regularly change your containers and solutions unless wearing daily disposable lenses


  • Do not use your lenses beyond their wearing schedule and never re-use daily disposable contact lenses
  • Do not wear contact lenses if your eyes are red and sore
  • Do not wear contact lenses in the shower, the bath or while swimming
  • Do not wear contact lenses whilst sleeping
  • Do not allow your lenses to come into contact with tap water

A study carried out by UCL at Moorfiields Hospital found that people who wear reusable contact lenses such as monthly lenses are four times as likely to develop a rare sight-threatening eye infection than those who wear daily disposable contact lenses.

Can you Treat A Corneal Ulcer?

Yes, in most cases a corneal ulcer can be treated successfully. The cause of the corneal ulcer will depend on the type and duration of the treatment.

If you suspect you have a corneal ulcer and you are a contact lens wearer remove your contact lenses immediately and seek medical advice - it is a good idea to take your lenses and the lens case with you - as this may help in determining the bacteria present in the eye.

Corneal ulcers caused by a bacterial infection can be treated with antibiotics. If caught quickly enough and treatment started early, the infection will subside, and the eye will be able to heal.
If antibiotics aren't effective, then the source of the infection might be fungal, viral or microbial in nature. You may require samples and cultures to be taken to determine the kind of infection that is present, and which type of treatment is needed.

If the cause of the corneal ulcer is fungal in nature then Anti-fungal medications can be administered, usually as both eye drops and pills. Whilst antibiotics work well against bacteria, anti-fungal medication treats fungal infections by killing or stopping the growth of dangerous fungi in the body.

Anyone who suspects that they may have a corneal ulcer should seek medical attention from an eye care professional immediately. Failure to treat them quickly and properly can lead to permanent and irreversible damage to the eye, which can cause a drastic loss of vision, or even blindness. 

Author: John Dreyer Optometrist Bsc(Hons), MCOPTOM, DipCLP
Created: 10 Apr 2018, Last modified: 20 May 2024