Confocal microscopy provides a new, noninvasive way of imaging the human cornea in vivo. One of its most important clinical uses is the diagnosis and management of infectious keratitis. The authors used tandem scanning confocal microscopy to image the corneas in two culture-proven cases of Aspergillus keratitis. Fungal hyphae were imaged as high-contrast filaments 6 microns in diameter from 60 to 400 microns in length. Confocal microscopy may be a fast and safe diagnostic tool in determining the presence of fungal hyphae in vivo within the human cornea.