A major cause of blindness worldwide, ulcers produce corneal scarring or perforation. They occur in the central or marginal areas of the cornea, vary in shape and size and may be singular or multiple. Prompt treatment (within hours of onset) can prevent visual impairment.
CAUSES
corneal ulcers usually result from protozoan, bacterial, viral or fungal infections. Common bacterial sources include staphylococcus aureus, viral sources, herpes simplex type 1, variola, vaccinia, and varicella-zoster viruses; and common fungal sources Candida, Fusarium, and Cephalosporium.
Other causes include trauma, exposure, reaction to bacterial infections, toxins and allergens. Tuberculoprotein causes a classic phyctenular keratoconjunctivitis; vitamin A deficienecy results in thickening of the conjunctiva secondary to vitamin A deficiency (xerophthalmia); and fifth cranial nerve lesions, in neurotrophic ulcers.
SIGNS & SYMPTOMS
Typically, corneal ulceration begins with pain (aggravated by blinking) and photophobia, followed by increased tearing. Eventually, central corneal ulceration produces pronounced visual blurring. The eye may appear infected. If a bacterial ulcer is present, pus-filled discharge is possible.
TREATMENT
Prompt treatment is essential for all forms of corneal ulcers to prevent complications and permanent visual impairment. Treatment aims to eliminate the underlying cause of the ulcer and to reduce pain.
Until culture results identify the causative organism, treatment consists of systemic and broad-spectrum antibiotics. Once the causative agent is identified, specific treatments vary. Treatment of corneal ulcers never includes an eye patch because patching creates the dark, warm, moist environment ideal for bacterial growth.