Corneal Ulcer Overview
A corneal ulcer is an open sore on the cornea, the thin clear structure overlying the iris (the colored part of the eye).
Corneal Ulcer Causes
- Most corneal ulcers are caused by infections.
- Bacterial infections cause corneal ulcers and are common in people who wear contact lenses.
- Viral infections are also possible causes of corneal ulcers. Such viruses include the herpes simplex virus (the virus that causes cold sores) or the varicella virus (the virus that causes chickenpox and shingles).
- Fungal infections are an unusual cause of corneal ulcers and may happen after injury with organic material such as branches or twigs. People who contract this type of infection have been treated with steroid eyedrops or are wearing contact lenses which are not properly disinfected.
- Tiny tears to the cornea may also cause corneal ulcers. These tears can come from direct trauma; scratches; or particles, such as sand, glass, or small pieces of steel. Such injuries damage the cornea and make it easier for bacteria to invade and cause a serious ulcer.
- Disorders that cause dry eyes can leave your eye without the germ-fighting protection of tears and cause ulcers.
- Disorders that affect the eyelid and prevent your eye from closing completely, such as Bell's palsy, can dry your cornea and make it more vulnerable to ulcers.
Chemical burns or other caustic (damaging) solution splashes can injure the cornea.
- People who wear contact lenses are at an increased risk of corneal ulcers. In fact, your risk of corneal ulcerations increases tenfold when using extended-wear (overnight) soft contact lenses. Extended-wear contact lenses are those contact lenses that are worn for several days without removing them at night. Contact lenses can damage your cornea in many ways.
- Scratches on the edge of your contact lens can scrape the cornea’s surface and make it more open to bacterial infections.
- Similarly, tiny particles of dirt trapped underneath the contact lens can scratch the cornea.
- Bacteria may be on the lens or in your cleaning solutions and, thus, get trapped on the undersurface of the lens. If your lenses are left in your eyes for long periods of time, these bacteria can multiply and cause damage to the cornea.
- Wearing lenses for extended periods of time can also block oxygen to the cornea, making it more susceptible to infections.