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Corneal Ulcers (Keratitis)


A corneal ulcer is an open sore on the cornea, which is the transparent dome overlying the colored iris of the eye. A corneal ulcer usually results from an eye infection, though it can be caused by severe dry eye or other eye disorders.


Symptoms of corneal ulcers may include:

  • Redness

  • Severe pain

  • Foreign body sensation

  • Tearing

  • Discharge

  • Blurred vision

  • Sensitivity to light

  • Swelling of the eyelids

  • A white spot on the cornea sometimes visible when looking in a mirror

Risk Factors

People at risk for corneal ulcers include:

  • Contact lens wearers

  • People who have or have had cold sores, chicken pox or shingles

  • People who use steroid eye drops

  • People with dry eye symptoms

  • People with eyelid disorders that prevent proper functioning of the eyelids

  • People who suffer injury or chemical burns to the cornea


Corneal ulcers are usually caused by the following types of infections:

  • Bacterial infections: This is common for contact lens wearers, especially for those using extended-wear lenses who sleep with their lenses in the eye. Corneal scratches from fingernails, paper cuts, makeup brushes, tree branches, and other causes can become infected by bacteria and lead to corneal ulcers or bacterial keratitis.

  • Viral infections: The virus that causes cold sores (the herpes simplex virus) may cause recurring outbreaks that are triggered by stress, an impaired immune system, or exposure to sunlight. Also, the virus that causes chicken pox and shingles (the herpes varicella-zoster virus) can cause corneal ulcers.

  • Fungal infections: Improper use of contact lenses or steroid eye drops can lead to fungal infections, which in turn can cause corneal ulcers. Also, a corneal injury that results in plant material getting into the eye can lead to fungal keratitis.

  • Acanthamoeba parasitic infections: Acanthamoeba are microscopic, single-celled amoeba that can cause human infection. They are the most common amoeba in fresh water and soil. Acanthamoeba corneal ulcer is particularly common in contact lens users, especially those who make their own homemade cleaning solutions, who practice poor lens hygiene, or have a history of swimming with their contact lenses in. When acanthamoeba enters the cornea it can cause severe infection.

Other causes of corneal ulcers include:

  • Burns caused by caustic chemicals found in the workplace or at home

  • Dry eye syndrome

  • Bell's palsy and other eyelid disorders that prevent proper eyelid function. If the eyelid does not function properly, the cornea can dry out.


Corneal ulcers/keratitis are commonly treated with anti-bacterial or anti-fungal eye drops, sometimes as frequently as every hour. In some cases, antifungal tablets may be prescribed or an injection of medication is given near the eye for treatment. When the infection is well under control or gone, steroid or anti-inflammatory eye drops may be used to reduce swelling and help prevent scarring.


Steroid eye drops should only be used under close supervision by your cornea specialist. It is possible that steroid eye drops may worsen an infection.

If corneal ulcers cause residual corneal scarring or thinning, corneal transplantation may be necessary to keep your vision. A corneal transplant can replace the damaged cornea with a healthy donor cornea to restore vision. If you think you have a corneal ulcer or symptoms of corneal ulcer, please call our office immediately so you can see Dr. Kim as soon as possible. Early treatment may help reduce the risk of complications. Frequent visits to your ophthalmologist may be necessary to eliminate the infection.

Contact us today!

Schedule an appointment with us online or call us at (408) 358-3932.

You will receive the latest in eyecare technology from our friendly eye doctors and staff committed to serving you.

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