A corneal ulcer is a break, erosion, or open sore in the front layer of the eye (cornea). Although usually superficial, ulcers can sometimes extend into the underlying middle layer (stroma) of the cornea. Ulcers are the most common cause of impaired vision and blindness in the world.
The most common cause of corneal ulcers is an abrasion or scratch caused by injury or as a result of contact lens overwear. Other causes may include viral infections (particularly with the herpes simplex or herpes zoster viruses), bacterial infections through contaminated eye drops, contact lenses or soil, fungi, vitamin A deficiency or protein malnutrition, use of corticosteroid eye drops, chemical damage, excessive exposure to air or ultraviolet light, or corneal attack by the body's own immune system (autoimmunity).
Eye conditions that may make a corneal ulcer more likely include "dry eye" (keratoconjunctivitis sicca), eyelid deformities (entropion, ectropion), diminished sensation in the cornea (more easily permits injury to occur), and an increased susceptibility to infection due to a lowered immune system (immunosuppressed state).
How is it diagnosed?
History: Symptoms may include eye pain that is worse with eye or lid movement, severe sensitivity to light (photophobia), blurred vision, tearing, and occasionally yellow drainage (pus). There may be a history of eye injury or recent eye disease. Although corneal ulcers are very painful, chronic ones may become less so.
Physical exam: An anesthetic eyedrop may need to be given to make the eye exam tolerable. If there is pus collecting behind the cornea, a dull gray circle will be present on the cornea (hypopyon). A fluorescein dye, instilled into the eye, fills the ulcer and reflects back green light when a florescent light is shown on it.
Tests: Visual acuity testing will be done to determine the sharpness and discrimination of the vision. If an infection is expected, material from the ulcer may be removed by swab and cultured to identify the microorganism responsible.
How is corneal ulcer treated?
Superficial, noninfectious ulcers caused by mechanical injury usually heal quickly.
If caused by an infection, treatment must begin as soon as possible. Antibiotic medication will be given by mouth, by eyedrops, and/or by injection into vein (intravenously) for four to five days.
Underlying conditions that may have caused the ulcer need to be corrected.
Noninfectious ulcers that fail to heal may respond to a "bandage" contact lens that protects the area, or to a temporary joining of the eyelids (tarsorrhaphy).
What might complicate it?
An infected ulcer can cause softening and perforation of the cornea, infection of the entire eye (panophthalmitis), and partial or total loss of vision. Treatment is difficult if the individual is immunosuppressed or if corticosteroids are used to control the inflammation. If the underlying cause is not corrected, ulcers can recur.
Superficial, noninfectious ulcers caused by mechanical injury usually heal quickly. More severe corneal ulcers can cause minimal to severe scarring that decreases vision enough to warrant a corneal transplant to restore sight. Depending on the cause, corneal ulcers can recur.