Fungal keratitis is a major blinding eye disease found throughout the world, particularly in developing countries. Given the recent increase in Fusarium keratitis infections in contact lens wearers owing to contact lens solutions, a warning was recently issued by the Food and Drug Administration, making it a public health concern in developed countries.To show the advantages of in vivo confocal microscopy imaging using the Heidelberg Retina Tomograph II-Rostock Cornea Module (HRTII-RCM) in the early diagnosis of fungal keratitis.HRTII-RCM confocal microscopy was performed on five patients presenting with fungal keratitis and on three donor corneas contaminated with Fusarium solani, Aspergillus fumigatus and Candida albicans.Direct microscopic evaluation of corneal smears and culture revealed the presence of F solani in four cases and C albicans in one case. HRTII-RCM examination of the infected patients and contaminated donor corneas revealed numerous high-contrast elements resembling Fusarium, Aspergillus hyphae or Candida pseudofilaments in the anterior stroma.HRTII-RCM in vivo confocal microscopy is a new, non-invasive and rapid technique for the early diagnosis of fungal keratitis, showing high-resolution images resembling fungal structures in the early phase of the disease.