ACRIDINE-ORANGE STAINING FOR RAPID DIAGNOSIS OF ACANTHAMOEBA-KERATITIS

Acanthamoeba keratitis is uncommon, but one of the most severe infecti ous diseases of the cornea. Delayed diagnosis or misdiagnosis as bacte rial or herpes simplex keratitis leads to extensive corneal inflammati on and profound visual loss. Therefore, accurate and rapid diagnosis o f Acanthamoeba keratitis is essential for successful treatment and goo d prognosis. We evaluated the usefulness of acridine orange staining f rom corneal scrapings and contact lens solutions for the rapid diagnos is of four consecutive cases of Acanthamoeba keratitis. Gram stain and culture on nonnutrient agar plates with Escherichia coli overlay were also made. Corneal scrapings stained with acridine orange revealed ye llow-to-orange polygonal, cystic structures consistent with the appear ance of Acanthamoeba among inflammatory cells and the corneal epitheli al cells. The contact lens case solutions of two patients also showed numerous cysts with double wall. Some organisms from the third patient were identified as Acanthamoeba castellani and others as Acanthamoeba lugdunensis. Based on the acridine orange staining results in four ca ses of Acanthamoeba keratitis, this stain is recommended as a simple a nd reliable method for the rapid diagnosis of this disease. (C) 1998 J apanese Ophthalmological Society.