Rapid Detection of Acanthamoeba Cysts in Corneal Scrapings by Lactophenol Cotton Blue Staining

To the Editor.  —Acanthamoeba keratitis is increasingly being reported from developing countries where contact lens wear is not necessarily a predisposing factor.¹ This is mainly due to the increased awareness and heightened suspicion of the occurrence of this form of keratitis.Currently, direct microscopic examination of smears of ulcer scrapings stained by the Giemsa, Gram's, or Wright's staining techniques affords the simplest and least expensive means of arriving at a rapid presumptive diagnosis of this condition. In such smears, however, the organisms may not always be readily distinguished from the surrounding tissue cells. Other methods, involving the use of calcofluor white,² fluorescent antibodies,³ and fluorescein-conjugated lectins,⁴ are very specific, but they are elaborate, expensive, and require the use of special microscopes.We have treated three patients with Acanthamoeba keratitis where the diagnosis was first suspected by the detection of double-walled, cystlike structures in corneal scrapings