Corneal Ulcers

What is a corneal ulcer?

The cornea is the clear, dome-shaped layer at the front of your eye. It protects the inner structures of the eye and plays a key role in focusing light, which allows you to see clearly.

A corneal ulcer is an open sore on the cornea. It can develop when the surface of the cornea becomes damaged, allowing bacteria, viruses or fungi to infect the tissue underneath. Some ulcers are sterile, meaning no infection is present. These typically result from dry eyes, autoimmune conditions or physical trauma rather than infectious causes.

In some cases, the body's immune system sends white blood cells to the affected area. This response is called an infiltrate and can appear as a cloudy patch on the cornea.

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Common causes

Corneal ulcers can develop for several reasons. One of the most common causes is contact lens wear, particularly when lenses are not cleaned properly, worn for too long, or used while swimming or sleeping. The risk increases if lenses trap bacteria against the eye or cause small scratches on the corneal surface. Daily disposable lenses generally carry lower infection risk than monthly lenses, but proper hygiene remains essential for all lens types.

People with dry eye syndrome may also be more vulnerable. When the eye does not produce enough tears, or tears evaporate too quickly, the cornea loses some of its natural protection against infection.

Viral infections can trigger corneal ulcers too. The herpes simplex virus, which causes cold sores, can affect the eye and lead to a condition called herpes keratitis. This can cause recurring ulcers if not managed carefully.

Physical injury to the eye is another cause. A scratch from a fingernail, a piece of grit, or exposure to chemicals can all damage the cornea and create an entry point for infection.

Inward-growing eyelashes, a condition known as trichiasis, can also contribute. When lashes repeatedly rub against the cornea, they cause irritation and small abrasions that may develop into ulcers over time. This problem can often be treated by removing the offending lashes.

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Symptoms to look out for

A corneal ulcer can cause noticeable discomfort. Common symptoms include:

• Eye pain, ranging from mild to severe
• Redness and swelling
• Watery or discharge from the eye
• Blurred vision
• Sensitivity to light
• A feeling that something is in your eye
• A visible white or grey spot on the cornea in some cases

Contact lens wearers or anyone experiencing these symptoms should seek immediate eye care advice. Left untreated, a corneal ulcer can lead to scarring or, in serious cases, permanent vision loss.

Treatment and when to get help

Treatment depends on the cause and severity of the ulcer. Bacterial infections are often treated with antibiotic eye drops, which usually require frequent application initially. Viral ulcers often require antiviral medication instead. Fungal infections, though less common, need antifungal treatment. Do not use over-the-counter eye drops without professional advice, as inappropriate treatment can worsen the condition.

Any suspected corneal ulcer should be assessed by an ophthalmologist rather than a GP, due to the potential severity and need for specialist examination. In the UK, you can go directly to an eye casualty department or A&E for urgent assessment. In severe cases where significant scarring occurs, corneal transplantation may be considered as a last resort.

While recovering, you will usually be advised to stop wearing contact lenses until the ulcer has fully healed. Your eye care provider will let you know when it is safe to resume lens wear.

Taking good care of your eyes can help reduce the risk of corneal ulcers. This means following hygiene guidelines for contact lenses, attending regular eye check-ups, and seeking prompt treatment for any eye discomfort or injury.

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