Rapid diagnosis of Acanthamoeba keratitis from corneal scrapings using indirect fluorescent antibody staining
R. J. Epstein, L. A. Wilson, G. S. Visvesvara and E. G. Plourde Jr
Two soft contact lens wearers using a homemade saline solution developed
corneal stromal inflammation and epithelial ulceration and were both
treated for months with a presumptive diagnosis of herpes simplex
keratitis. Subsequently, corneal scrapings revealed refractile, cystic
structures consistent with the appearance of Acanthamoeba. This was rapidly
confirmed by indirect fluorescent antibody studies, and Acanthamoeba
castellani was later identified by growth in culture in both cases.
Acanthamoeba is being reported with increasing frequency as a pathogen
responsible for chronic stromal keratitis and ulceration in contact lens
wearers. Since specific therapy is required to control this organism, rapid
diagnosis is essential. Indirect fluorescent antibody staining of corneal
scrapings provides a simple means of accomplishing this goal with a high
degree of accuracy.
