NEW YORK (Reuters Health) – A two-step hydrogen peroxide system is better than two other commonly used cleaning systems at destroying Acanthamoeba, an important cause of keratitis in contact lens wearers, according to a report by Austrian researchers.
Dr. Horst Aspock, from the University of Vienna, and colleagues compared the antimicrobial activity of three cleaning solutions against three different species of Acanthamoeba: A. castellanii, A. hatchetti, and A. lenticulata.
The solutions included Meni Care Plus, a multipurpose solution produced by Menicon Pharma, Titmus H2O2, a two-step hydrogen peroxide system produced by Ciba Vision Corp., and Oxysept Comfort, a one-step hydrogen peroxide system produced by Pharm Allergan.
After 8 hours of soaking, all of the cleaning solutions had destroyed the trophozoites of all species, the investigators note in the February issue of the British Journal of Ophthalmology. However, for cyst destruction, the Titmus system was clearly superior to the other two and actually killed A. castellanii and A. hatchetti cysts after only 30 minutes of exposure.
The Oxysept system performed the worst of the three with viable cysts of all species still remaining after 8 hours of exposure. The Oxysept system may neutralize hydrogen peroxide too quickly to allow effective destruction of Acanthamoeba cysts, the authors postulate.
There are effective means of destroying Acanthamoeba cysts and trophozoites that exist in contact lens cases. "However, the development and use of storage solutions which are effective against Acanthamoeba is of great importance," the investigators emphasize. Based on the current findings, they recommend the Titmus system.