How to Diagnose Keratitis

Keratitis is a generic term that applies to any inflammation of the cornea. The most common cause is a bacteriological infection and this can be a sight-threatening process. Bacterial keratitis is characterized by rapid progress and some forms can completely destroy the cornea in 1 to 2 days.

Instructions

• 1

  Take the patient's history. Patients with bacterial keratitis usually present with a sudden onset of pain, sensitivity to light and a decrease in vision.

• 2

  Document risk factors for bacterial keratitis. Patients frequently wear contact lenses, have recent trauma to the cornea, including surgery, or use eye medication. Other causes include a suppressed immune system, corneal disease and tear deficiencies.

• 3

  Conduct a physical examination of the eye. Common findings include an ulcerated epithelium, stromal inflammation, stromal tissue loss and stromal edema. Other characteristics include folds in the Descemet membrane, edema in the upper eyelid and inflamed plaque in the endothelium.

• 4

  Identify the specific causative agent. Take scrapings of the corneal ulcer that include the edges. The scraping should be cultured in blood, chocolate and Sabouraud agar. Common stains include acid-fast stain, Gram and Giemsa. Use an acridine orange or calcofluor white stain if you suspect a fungal or amoebic infection.

• 5

  Perform slit lamp photography when the specific etiology is in doubt. This can be especially helpful in chronic cases that do not respond to antibiotics. A B-scan ultrasound can eliminate endophthalmitis as a diagnosis in cases where the eyes have severe corneal ulcers.