Assessment of Confocal Microscopy for the Diagnosis of Polymerase Chain Reaction-Positive Acanthamoeba Keratitis

Acanthamoeba keratitis is a serious vision-threatening disease. In vivo confocal microscopy can help in this challenging diagnosis, especially when PCR is delayed, shows negative results, or is not available. Target images and trophozoite-like images are pathognomonic of AK. Clusters of hyperreflective objects are highly specific of AK. However, the overall sensitivity of in vivo confocal microscopy features of AK is low. In addition to the clinical features, microbiological tests (direct examination and cultures of corneal scrapings), and PCR, in vivo confocal microscopy allows for more rapid diagnosis and treatment initiation, potentially leading to an improved outcome.