Condition

Corneal ulcer

Medical reviewer Mr Mohamed Mohyudin· Last recorded site review

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What it is

A corneal ulcer is an open sore on the cornea, the clear dome at the front of the eye. It is most often caused by a bacterial, viral, fungal or parasitic infection, and if not treated quickly it can scar the cornea and permanently affect vision.

Warning symptoms

A corneal ulcer usually causes severe, obvious symptoms in one eye.

  • A painful, red, watering eye
  • Blurred vision and marked light sensitivity
  • A feeling that something is in the eye
  • Sometimes a visible white or grey spot on the cornea

Causes and risk factors

Infection is the main cause, and the biggest risk factor is contact lens wear, especially sleeping in lenses or poor hygiene. Eye injuries, severe dry eye, and a weakened immune system also raise the risk.

Treatment and urgency

A corneal ulcer is an emergency. Remove contact lenses and seek same-day eye care. Treatment usually involves intensive antimicrobial drops, sometimes hourly, and close follow-up. Treated early most ulcers heal, but delay can lead to scarring and lasting vision loss.

Practical guides

Contact lens careSafe removal, hygiene, sleeping in lenses, and why water and lenses never mix.How to use eye dropsSimple steps to put in eye drops safely: wash hands, one drop, avoid touching the bottle tip to your eye.

Treatments & Surgery

Corneal transplantSurgery to replace part or all of a damaged cornea with healthy donor tissue to restore vision.

Frequently asked questions

Is a corneal ulcer an emergency?

Yes. A corneal ulcer is a sight-threatening emergency. A painful, red eye with blurred vision and light sensitivity, especially in a contact lens wearer, needs same-day eye care.

What causes a corneal ulcer?

Most corneal ulcers are caused by infection, and the biggest risk factor is contact lens wear, particularly sleeping in lenses or poor hygiene. Injuries and severe dry eye also increase the risk.

Can a corneal ulcer heal completely?

Treated early, many corneal ulcers heal well. However, delay can cause permanent scarring and vision loss, which is why urgent treatment is so important.

Your next step

Take this to your appointment

Write down what has changed, when it started, your current medicines and the questions you want answered. Take these to your eye-care appointment.

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Sudden loss of sight, severe eye pain or a dark curtain across vision needs immediate assessment. Do not wait to complete a worksheet.

Sources for this information

These references support the information on this page. Follow the linked source for its full context.