[A nation-wide survey on the occurrence of amoebic keratitis in Japan].

Acanthamoeba keratitis in Japan was first reported by Ishibashi in 1988. Since then, the incidence of Acanthamoeba keratitis has gradually increased. We retrospectively analyzed 39 cases, 42 eyes, of amoebic keratitis reported in Japan from 1988 to September 1993. Of the 39 patients, 35 (89.7%) wore contact lenses, 32 (82.1%) soft contact lenses, and 3 (7.7%) hard contact lenses, and 4 (10.3%) did not wear contact lenses. Of the 4 patients without contact lenses, 3 had a history of trauma. Acanthamoeba keratitis is often difficult to diagnose. Twenty-four cases were misdiagnosed as herpetic keratitis. Early diagnosis and adequate therapy are important.