ACANTHAMOEBA TROPHOZOITE AND CYST ADHERENCE TO 4 TYPES OF SOFT CONTACT-LENS AND REMOVAL BY CLEANING AGENTS

Trophozoite and cyst adherence of two Acanthamoeba keratitis strains ( PHL/530 and PHL/978) to four types of unworn soft contact lens and the ir removal by cleaning agents were studied. Greater adherence of the t rophozoites compared with the cysts was recorded for both strains. Tro phozoites of PHL/530 adhered in greater numbers to type I lenses (61.4 % poly[2-hydroxyethyl methacrylate-38.6% water), with no differences b etween type II (30% lidofilcon A-70% water), III (55% bufilcon A-45% w ater) and IV lenses (42% etafilcon A-58% water). Adherence of PHL/978 trophozoites to type II lenses was decreased compared with their adher ence to the other lenses. Cysts of both strains showed greater adheren ce to type I and III lenses. Interstrain differences in trophozoite ad herence occurred, with PHL/530 showing greater adherence to type I and II lenses. Recommended cleaning procedures using three commercial sol utions were effective in removing Acanthamoeba from the lenses. This s tudy indicates the possible role of adherence to contact lenses in the acquisition of Acanthamoeba keratitis, but shows that correct use of commercial cleaning agents may be important in the prevention of infec tion.