Changing patterns of infectious keratitis: overview of clinical and histopathologic features of keratitis due to acanthamoeba or atypical mycobacteria, and of infectious crystalline keratopathy.

Acanthamoeba keratitis, infectious crystalline keratopathy and atypical mycobacterial keratitis have recently emerged as important types of infectious keratitis. These corneal infections have been associated with contact lens wear and with corneal surgical procedures such as radial keratotomy and penetrating keratoplasty, and the clinical setting of each of these infections is important in alerting the clinician to the possible diagnosis. There have been improvements in rapid diagnostic techniques for such infections in the last several years. Treatment has also improved, but remains a difficult problem, especially for Acanthamoeba. An overview of recent developments in the clinical and histopathologic methods for diagnosis and treatment options of these three corneal infections is provided.