A corneal ulcer is a sore or defect in the cornea, the clear structure at the front of the eye that is located in front of the pupil and the iris (the colored part of the eye). Corneal ulcers can be very serious and must be evaluated and treated, as severe damage to the eye and even blindness can sometimes occur. Signs and symptoms of a corneal ulcer often include eye redness, pain, foreign body sensation/irritation, eyelid swelling, blurred vision, sensitivity to light, tearing, and mucous discharge or pus. If an ulcer is large enough, it may be visible to the naked eye as a white spot located over the iris.
The cornea is an important structure that aids in focusing images clearly, and it is an important first line of defense against eye infection or injury. The layer of cells that lies on the surface of the cornea (epithelium) forms an important protective barrier; however, certain conditions can degrade the integrity of the epithelium and increase the risk of corneal ulcers. The risk of corneal ulcer increases for people who are contact lens wearers, have dry eye, have a history of cold sores, chicken pox, shingles, or diabetes, use steroid drops, have eyelid disorders (such as Bell’s Palsy) that do not allow the lids to open and close properly, or have had injuries or burns to the cornea.
Ulcers can be caused by infectious agents such as bacteria, viruses, fungi, and parasites, but they can also be noninfectious, developing in corneas that do not have normal sensation (such as following some episodes of shingles or in some diabetic patients). An eye exam will confirm the diagnosis of an ulcer by highlighting damaged areas using fluorescein dye eyedrops and by observing thinning or inflammatory signs in the corneal tissue.
Treatment typically involves the use of antibiotic, antifungal, or antiviral drops, but sometimes other treatments such as oral medications or injections of medications in the area around the eye may be required. Once an ulcer has healed, steroid or anti-inflammatory drops are sometimes used to resolve any residual inflammation or to try to reduce or prevent scarring. Steroid drops, however, should never be prescribed by anyone other than an eye care professional, as steroids can sometimes lead to worsening of infections or to corneal thinning. If ulcers have resulted in significant scarring that has caused vision loss, surgical intervention may be required.
A special note for contact lens wearers: contact lenses do carry a risk of eye infection, and this risk can be reduced by following professional lens care guidelines. Extended wear of lenses, dryness, dusty/dirty environments, and poor hygiene all contribute to an increased risk of infection, which, if serious enough, can cause permanent vision problems or an inability to wear contact lenses in the future. Make sure to replace lenses and storage cases frequently, do not reuse solution or use expired solution, store contacts in disinfecting solutions, not saline, and avoid contact with water while wearing your lenses. Never wear contact lenses that were not prescribed by an eye care professional.