Radial keratoneuritis as a presenting sign in Acanthamoeba keratitis

Abstract

Three myopic patients who wore soft contact lenses developed unilateral Acanthamoeba keratitis that presented with unusual infiltrates that appeared to be located along the corneal nerves. These infiltrates were found in the midstroma, beginning paracentrally, and extending to the limbus in a radial pattern. The epithelium overlying these infiltrates was intact. In two patients, the central epithelium had a stippled, almost dendritiform appearance leading to the misdiagnosis of herpes simplex keratitis. Cultures from corneal scrapings of two patients and cultures of a corneal biopsy from one patient, which included an area of presumed neural involvement, grew Acanthamoebae. All three patients used homemade saline solutions (salt tablets dissolved in distilled water). In one patient, Acanthamoebae were found in the contact lens case solution. In our recent experience, Acanthamoebae have also been found in the distilled water bottle and the saline solution made from distilled water and salt tablets in two additional patients with A. keratitis. Distilled water, which is not sterile, has proven to be one potentially avoidable source of A. keratitis in contact lens wearers.