Propylene glycol used as an ophthalmic demulcent in certain contact-lens care systems has been included recently among factors responsible for increasing Acanthamoeba keratitis. In this study, we provide evidence that propylene glycol as well as examined contact-lens solutions containing it induce rapid differentiation of acanthamoebae into pseudocysts.
The partial resistance of the pseudocysts and their reversibility to viable trophozoites even after 24-h exposure to the contact-lens solutions indicate a potential risk of infection to contact-lens users.