A corneal infection is an infection of the transparent front part of the eyeball (the "cornea") that allows light into the eye. Infections can be due to micro-organisms (germs) such as bacteria, fungi, parasites and viruses. In Singapore, the most common corneal infections are due to bacteria.

Symptoms and signs of a corneal infection include:

• Eye pain
• Redness and swelling
• Tearing
• Eye discharge
• Blurring of vision
  

These usually occur suddenly and worsen over a few days, but may sometimes develop over weeks.

Contact lens-related infections are the most common cause of corneal infections in Singapore. Good contact lens hygiene and habits can reduce the risk of infections.

Healthy contact lens wear includes:

• Proper contact lens cleaning and hygiene
• Regular replacement of disposable contact lenses
• Regular replacement of contact lens cases as well as cleaning solutions
• Minimising contact lens wear time
  

 Activities that carry a high risk of infection and should be avoided include:

• Overnight wear and sleeping with contact lenses
• Swimming or showering with contact lenses
• Contact with tap water
  

Corneal infections can also occur after eye trauma and injury. Many of these are seen in work site-related injuries and can be prevented with the appropriate use of safety goggles.

What causes corneal infections?

Corneal infections usually occur because of exposure to bacterial, fungal or other microbiological agents. Contact lens wear, associated with poor contact lens hygiene is the most common cause.

Apart from contact lens-related infections, corneal infections can also occur following eye injury, or due to pre-existing conditions or diseases of the cornea, e.g. cornea oedema.

A corneal infection may be suspected during the examination by an ophthalmologist. Once a diagnosis is made, samples of the micro-organism are obtained by gentle scraping from the site of the corneal infection and sent for microscopic examination and culture. This will allow the doctor to identify the exact micro-organism and the type of medication it is sensitive to.

How are corneal infections treated?

Corneal infections are usually treated with anti-infective eye drops and eye ointments. In the case of bacterial infections, antibiotic eye drops are prescribed. Patients with severe corneal infections may be admitted into hospital, to allow the eye drops to be applied intensively (usually every hour, even through the night) and for close monitoring of the infection.

Is surgery necessary?

Surgery may be needed for very severe corneal infections, especially if the infection is not responding to anti-infective eye drops or causing serious complications such as corneal thinning and perforation. Even after the infection is cured, surgery may still be needed if the infection has resulted in corneal scarring and poor vision. Surgery is performed to remove the infected or scarred cornea and replace it with healthy corneal tissue ("corneal transplantation").