What is this condition?

A major cause of blindness worldwide, corneal ulcers produce scar­ring or perforation of the cornea. They occur in the central or marginal areas of the cornea, but marginal ulcers are the most common form. A person may have one or several ulcers, of varied size and shape. Prompt treatment (within hours of onset) can prevent visual impairment.

What causes it?

A corneal ulcer generally results from infections by protozoa, bacteria, viruses, or fungi. Other causes include trauma, exposure, vitamin A deficiency, toxins, and allergens.

What are its symptoms?

Typically, a corneal ulcer causes pain (aggravated by blinking) and sensitivity to light, followed by increased tearing. Eventually, a central corneal ulcer blurs vision markedly. Bacterial ulcers may produce a pus-filled discharge.

How is it diagnosed?

A history of trauma or use of contact lenses and a penlight exam that reveals an irregular corneal surface suggest a corneal ulcer. Fluoresce-in dye, instilled in the conjunctival sac, stains the outline of the ulcer and confirms the diagnosis. Cultures of corneal scraping may identify the causative bacterium or fungus.

How is it treated?

Treatment aims to relieve pain and eliminate the underlying cause of the ulcer, as follows:

• Pseudomonas aeruginosa: the antibiotics Aerosporin and Garamycin, given topically and by subconjunctival injection, or Geocillin and Tobrex given intravenously. Since this type of corneal ulcer spreads so rapidly, it can cause corneal perforation and loss of vision within 48 hours. Immediate treatment and isolation of hospitalized patients are required. Eye coverings are never used when treating bacterial corneal ulcers .
• herpes simplex type 1 virus: hourly topical application of Herplex or Vira-A Ophthalmic. Corneal ulcers resulting from a viral infection often recur .
• varicella-zoster virus: a topical sulfonamide ointment applied 3 to 4 times daily to prevent secondary infection. These lesions are typically painful, so the person also receives pain relievers .
• fungi: instillation of Natacyn eyedrops for Fusarium, Cephalosporoium, and Candida
• vitamin A deficiency: correction of dietary deficiency or malabsorption of vitamin A
• neurotropic ulcers or exposure keratitis: frequent instillation of artificial tears or lubricating ointments and use of a plastic bubble eye shield.

Prompt treatment is essential for all forms of corneal ulcer to prevent complications and permanent vision problems or blindness.