The treatment course of Acanthamoeba keratitis (AK) is often lengthy and not fully effective because of the many potential strains of the organism to contend with and the fluctuating nature of the disease. But closer in vivo monitoring of potentially causative pathogens in real time could help corneal experts develop better treatment protocols. A retrospective chart review recently demonstrated that in vivo confocal microscopy (IVCM) can noninvasively identify Acanthamoeba cysts and their reactions to ongoing treatment.

Researchers analyzed 14 eyes of 11 contact lens wearers seen at the Doheny Eye Center of UCLA between August 2014 and March 2017; all were diagnosed with AK and then underwent corneal imaging with IVCM on follow-up. Clinical improvement occurred in all patients after treatment. Confocal microscopy was able to identify Acanthamoeba cysts in all culture-confirmed cases of keratitis. The study showed a significant correlation between Acanthamoeba cyst density reduction and duration of antiamoebic treatment—the technology helped reveal an average 5.3% reduction in cyst density with each month of treatment.

Though IVCM remains a tool for researchers rather than clinicians, use of the technology could help tertiary care centers monitor treatment response in patients with AK, the study says. Researchers believe the quantifiable Acanthamoeba cyst density reduction following treatment could be of clinical value for disease prognostication and monitoring, as well as therapeutic decision-making.

Wang YE, Tepelus TC, Gui W. Reduction of Acanthamoeba cyst density associated with treatment detected by in vivo confocal microscopy in Acanthamoeba keratitis. Cornea. January 9, 2019. [Epub ahead of print].