Diagnosis of Acanthamoeba keratitis in vivo with confocal microscopy

We present eight cases of Acanthamoeba keratitis. In each case, the Acanthamoeba organisms were visualized in the epithelium and anterior stroma using tandem scanning confocal microscopy. The organisms were highly re- flective, ovoid, and were 10-25 μm in diameter. The Acanthamoeba organisms in the human corneas were identical in size and shape to Acanthamoeba organisms on an agar plate visualized with the same confocal microscope. Confocal microscopy is a useful method for identifying Acanthamoeba organisms in vivo within the corneal epithelium and anterior stroma.