THE INCIDENCE of Acanthamoeba keratitis, a potentially blinding disease, is increasing. From 1973 to 1984, there were 31 cases, primarily associated with penetrating eye trauma or exposure to contaminated water. Since 1984, there have been more than 100 new cases, 90% being among wearers of contact lenses.
This apparently relates to the overall increase in the use of contact lenses. In 1980, 14.5 million people wore contact lenses; in 1985, 23.1 million people wore them (MMWR 1986;35:405-408; MMWR 1987;36:397-398, 403-404; JAMA 1987;258:17-18). Because of the increased incidence and seriousness of this problem, the Contact Lens Association of Ophthalmologists (CLAO) has issued a policy statement that describes the disease and gives guidelines for its prevention.
Acanthamoeba organisms commonly live in fresh water and soil, but have also been isolated from salt water, dust, and hot tubs. They are resistant to freezing, drying, microbial agents, and chlorine at the levels routinely used