ACANTHAMOEBA-KERATITIS

Acanthamoeba species are an important cause of microbial keratitis tha t may cause severe ocular inflammation and visual loss. The first case s were recognized in 1973, but the disease remained very rare until th e 1980s, when an increase in incidence mainly associated with contact lens wear was reported. There is an increased risk when contact lens r insing and soaking solutions are prepared with nonsterile water and sa lt tablets. The clinical picture is often characterized by severe pain with an early superficial keratitis that is often treated as herpes s implex infection. Subsequently a characteristic radial perineural infi ltration may be seen, and ring infiltration is common. Limbitis and sc leritis are frequent. Laboratory diagnosis is primarily by culture of epithelial samples inoculated onto agar plates spread with bacteria. D irect microscopy of samples using stains for the cyst wall or immunost aining may also be employed. A variety of topically applied therapeuti c agents are thought to be effective, including propamidine isethionat e, clotrimazole, polyhexamethylene biguanide, and chlorhexidine. Vario us combinations of these and other agents have been employed, often re sulting in medical cure, especially if treatment is commenced early in the course of the disease. Penetrating keratoplasty is preferably avo ided in inflamed eyes, but may be necessary in severe cases to preserv e the globe or, when the infection has resolved, to restore corneal cl arity for optical reasons. (C) 1998 by Elsevier Science Inc. All right s reserved.