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Corneal Ulcer

More than an eye sore

iStock_000000515593_LargeAlthough some bacteria can invade a healthy cornea, most enter through a defect in the corneal surface, such as tiny scratches on the corneal surface caused by a foreign body or even from rubbing the eye.

A corneal ulcer is an open sore on the cornea, the clear front covering of the eye. It is a potentially sight-threatening condition.

Corneal ulcers generally occur when the eye’s natural resistance to infection has been compromised, such as from contact lens wear or trauma. Most corneal ulcers are caused by bacterial infection and are related to contact lens wear. The most common bacteria that cause such infections are Pseudomonas and Staphylococcus. In some developing countries, trauma and fungal infection are the leading causes of corneal ulcers.

Figure 1. A large whitish patch on the cornea due to a severe corneal ulcer

Figure 1. A large whitish patch on the cornea due to a severe corneal ulcer

Symptoms of Corneal Ulcer

Patients with a corneal ulcer may experience:

  • Eye redness
  • Pain
  • A feeling that something is in the eye
  • Tearing
  • Discharge from the eye

Some patients may notice a white or grey round spot on the cornea (Figure 1). Vision is usually affected in severe cases.

Causes of Corneal Ulcer

For a corneal infection to occur, the infecting organism must be capable of penetrating the natural defence mechanisms of the eye. These defences include the layers of the cornea, the tear film, and the lids and their mechanical wiping actions on the corneal surface.

Optometrist Showing Contact LensAlthough some bacteria can invade a healthy cornea, most enter through a defect in the corneal surface, such as tiny scratches on the corneal surface caused by a foreign body or even from rubbing the eye. People who wear contact lenses are at an increased risk of corneal ulcers, especially if they also have improper hygiene and poor contact lens habits.

Contact lenses are a suitable surface for bacteria to adhere to. Contact lenses with rough surfaces are more prone to bacterial adhesion and growth due to insufficient lens cleaning. These contact lenses sustain a large quantity of organisms in prolonged contact with the cornea, increasing the risk of an infection.

The normal tear film has protective antimicrobial components that may become disrupted by poor tear exchange caused by contact lens. This causes the accumulation of inflammatory debris or microorganisms that would typically be removed via the tear film and blinking action, allowing the eye to be more susceptible to an infection.

12417187_xlSelf-Care and Treatment

Early treatment can limit the scarring and vision loss caused by a corneal ulcer. Even a slight delay in assessment and treatment can increase the risk of a poorer outcome. Therefore, it is most important that you get an early assessment by an eye specialist if you suspect you have a corneal ulcer.

In the meantime, these are some measures you can take:

  • Remove your contact lens immediately
  • Do not 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

Corneal ulcers are typically treated with an intensive regime of antibiotic eye drops by the eye specialist and may take several weeks to months to heal. After healing, a scar may remain in the cornea which may impair vision depending on its location and density. In very severe cases, a corneal transplant may be necessary to prevent the spread of the infection or to replace a badly scarred cornea.

Healthy Contact Lens Habits

Healthy contact lens wear depends on many factors, including the type of lens, cleaning regime and wearing regime. Corneal ulcers are mainly caused by not following good contact lens habits.

  1. Do Daily Disposables

Daily disposable contact lenses are associated with lower risks of corneal ulcer. Since daily disposables require neither a case nor a cleaning regime, their use may reduce the risk of bacterial infection.

  1. Watch your Hygiene HabitsiStock_000000490612_Medium

Replace your lens storage case frequently (e.g. every three to six months) and improve your hygiene to lower your risk of corneal ulcer. Rubbing your contact lenses during cleaning is more effective in removing bacteria compared to the “no rub” alternative.

  1. Go Bare to Bed

Although some contact lenses may be approved for overnight wear, it is better not to sleep or nap while wearing contact lenses, as this may increase bacterial binding, compromise corneal health and impair wound healing. These effects are reduced, but not eliminated, with silicone hydrogel lenses.

Follow these Pointers

  • Always have a proper eye examination and contact lens fitting by an optometrist before purchasing contact lenses
  • Rub and rinse your contact lens with a multi-purpose solution during cleaning
  • Soak your lenses for at least 8 hours or overnight in newly prepared multi-purpose solution
  • Never sleep or swim with your contact lenses
  • Comply with your follow-up or aftercare regime recommended by your optometrist
  • Do not wear your contact lenses for longer than the wearing schedule recommended by your optometrist
  • If you experience any discomfort, pain or reduction in vision, stop contact lens wear and consult an optometrist or an eye specialist immediately
author

Dr Au Eong Kah Guan is Medical Director and Senior Consultant at Singapore International Eye Cataract Retina Centre, located at Mount Elizabeth Hospital, Singapore.
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author
Lim Yun Chong is an Optometrist at Singapore International Eye Cataract Retina Centre, located at Mount Elizabeth Hospital, Singapore.
Posted by ezyhealth on Nov 6 2014. Filed under Eye Health. You can follow any responses to this entry through the RSS 2.0. Both comments and pings are currently closed.

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