A corneal ulcer is an open sore on the cornea, the clear structuare in the front of the eye. The cornea overlies the iris, which is the colored part of the eye. A corneal ulcer will often appear as a gray to white area on the normally transparent cornea. Some corneal ulcers may be too small to see without adequate magnification and illumination.
Symptoms of a Corneal Ulcer
A corneal ulcer may cause redness, pain a feeling that something is in the eye, tearing, and pus or thick discharge draining from the eye. Vision might be blurry, and there may be an increase in pain when the person looks at bright lights
Causes of a Corneal Ulcer
Most corneal ulcers are caused by infections. Bacterial infections cause corneal ulcers and are common in people who wear contact lenses. Bacteria can directly invade the cornea if the corneal surface has been disrupted. Some bacteria produce toxins that can cause ulceration of the cornea. Viral infections are also possible causes of corneal ulcers. Viruses that may cause corneal ulcers include the herpes simplex virus (the virus that causes cold sores) and the Varicella virus (the virus that causes chickenpox and shingles). Fungal infections can cause corneal ulcers and may occur with improper care of contact lenses or overuse of eye drops that contain steroids.
Tiny cuts or scratches in the corneal surface may become infected and lead to corneal ulcers. These small cuts can come from direct trauma (for example, metallic, wood, glass, or almost any type of particles) that strike the cornea. Such injuries damage the corneal surface and make it easier for bacteria to invade and cause a corneal ulcer. A corneal abrasion is a larger loss of the corneal surface and may ulcerate if left untreated.
Disorders that cause dry eyes can leave the eye without the germ-fighting protection of moisture from the tear ducts and cause corneal ulcers.
Any condition which causes loss of sensation of the corneal surface may increase the risk of corneal ulceration. Chemical burns or other caustic (damaging) solution splashes can injure the cornea and lead to corneal ulceration.