Corneal ulcer

A corneal ulcer is an open sore on your cornea, which is the front part of your eye that covers your iris (the coloured part of your eye). 

Image credit: Depositphotos

The most common cause of a corneal ulcer is an eye infection.

The infection can be caused by:

• bacteria, such as Staphylococcus aureus or Pseudomonas aeruginosa
• viruses, such as those that cause cold sores or shingles 
• fungi – this is rare but may occur if your cornea is injured by a tree branch or twig
• parasites, such as Acanthamoeba which is found in fresh water and soil.

Pseudomonas aeruginosa and Acanthamoeba are associated with contact lens use. 

A corneal ulcer needs to be treated quickly to prevent further damage to your cornea and loss of vision.

Other causes can be due to an injury or scratch on the eye, or an inflammatory reaction such as severe eye allergies.

Who is at risk?

You’re at risk of corneal ulcers if you:

• use contact lenses, especially extended-wear (overnight) soft contact lenses or if you wear your lenses while swimming or showering
• have poor hygiene with contact lenses such as overtime wear or poor contact lens and case cleaning 
• use steroid eye drops
• have a condition that causes dry eyes
• have inflamed eyelids
• have eyelashes that grow inward 
• have eyelids that turn inward (entropion)
• have a condition that stops your eyelid from closing completely, eg, Bell’s palsy
• have an injury to your cornea, eg, due to a foreign body or chemical burn
• have severe eye allergies
• have a weakened immune system.

If you wear contact lenses, you’re more likely to get corneal ulcers because:

• bacteria on your lens or in the cleaning solution can get trapped under the lens
• the oxygen supply to your cornea can be affected if you wear your lenses for long periods
• a damaged lens might scrape your cornea
• dirt might get trapped under the lens and scratch your cornea.

The main causes of corneal ulcers that can seriously threaten your vision are injury and infection.

Symptoms of a corneal ulcer can include:

• a red eye
• moderate to severe pain
• the feeling that something is in your eye
• a watery eye
• pus or thick discharge from your eye
• blurry vision
• sensitivity to bright lights
• swollen eyelids
• a round white spot on your cornea.

It’s important to see your healthcare provider if you have these symptoms as a corneal ulcer needs to be treated as soon as possible to prevent further damage to your cornea and loss of vision.

After asking about your symptoms and risk factors, such as an eye injury or use of contact lenses, your healthcare provider will examine your eye and check your vision. They may use a special dye and microscope (called a slit lamp) to look at your eye. If they think you have an infection, they may take a sample from the ulcer to send to the lab for testing. The results can help them decide on the best treatment for you. 

You may be referred to an eye specialist (an ophthalmologist) for confirmation of the diagnosis. 

The image below shows a corneal ulcer in front of the iris (coloured part of the eye).

Image credit: Depositphotos

It’s important to get a corneal ulcer treated quickly to prevent further injury to your cornea. You may be referred to an eye specialist (ophthalmologist) urgently –especially if you have loss of vision.

If you have a chemical injury to your eye, your eye will be flushed with a saline solution. If an infection is suspected, you or your healthcare provider should remove any contact lenses if you’re wearing them – these may be sent to the lab to see if bacteria (bugs) are present on them, and if so what kind.

If your ulcer is caused by an infection, you’ll be given antibiotic, antiviral or antifungal medicine (usually eye drops) depending on the cause of the infection. You may have to use eye drops every hour for a few days. You may also be given pain relief medicines and eye drops to dilate your pupil which can also help with the pain. 

If your ulcer isn’t caused by an infection, you may be given anti-inflammatory and lubricating eye drops, and antibiotics to prevent infection.

If medicines don’t help, or if you have a severe ulcer, you may need corneal transplant surgery (keratoplasty). This is where your cornea is replaced with corneal tissue from a donor.

There are things you can do at home to help your symptoms after you start treatment for a corneal ulcer:

• put cool compresses on your eye, but be careful to keep water away from your eye
• don’t touch or rub your eye
• wash your hands often and dry them with a clean towel to prevent the spread of infection
• take pain medicines, such as paracetamol or ibuprofen
• don’t wear contact lenses or eye make-up.

Tell your healthcare provider straight away if your symptoms (such as blurry vision, pain, or discharge from your eye) get worse.

There are things you can do to reduce your risk of getting a corneal ulcer.

• Wear eye protection if you’re around small particles, eg, if your work or hobby involves hammering, sanding or grinding, or if you’re near sand or grit on a windy day.
• Use artificial tears to keep your eyes moist if you have dry eyes or if your eyelids don’t close completely. 
• Don't over-wear your contact lenses – only wear them for the amount of time advised. Replace them as prescribed and don't wear them at night unless they are designed to be slept in. 
• Clean your contact lenses and contact lens case properly.. 
• Don’t use saliva to wet your lenses as bacteria from your mouth can damage your cornea.
• Avoid swimming and showering with your contact lenses in.
• See your healthcare provider as soon as possible if:
  • you have symptoms of an eye infection (such as an itchy or watery eye, pus-like discharge, a red eye, sensitivity to light)
  • you injure your eye
  • you’ve had a corneal abrasion (a scratch on your cornea) and experience worsening of your vision or increasing pain.

With prompt treatment, most corneal ulcers get better in 2 to 3 weeks. However, sometimes there is scarring of the cornea that can interfere with your vision permanently.

If a corneal ulcer isn’t treated, you could lose some or all of your eyesight. You could get a hole in your cornea, infection, scarring, cataracts or glaucoma.

If you get scarring on your cornea that makes it difficult to see, you may need a corneal transplant.