[The diagnosis of Acanthamoeba keratitis. The identification of the first case in Russia].

The first case of keratitis caused by Acanthamoeba in a 28-year-old man who was admitted to a hospital on May 17, 1991 is described in the paper. He wore soft contact lenses for correction of myopia. Acanthamoeba was not initially suspected as the pathogen and diagnosis was delayed for 20 months. Acanthamoeba keratitis was confirmed by the culture of the parasite from corneal graft after the second keratoplasty and by cysts in wet mount with 10% potassium hydroxide and on Gram and Giemsa stain smears. The potassium hydroxide mount provides a rapid diagnosis, which makes the method highly useful in the differential diagnosis in Acanthamoeba and fungal keratitis.