DISPOSABLE CONTACT-LENSES AND BACTERIAL ADHESION - IN-VITRO COMPARISON BETWEEN IONIC HIGH-WATER-CONTENT AND NONIONIC LOW-WATER-CONTENT LENSES

An in vitro quantitative study of the adhesion of a Staphylococcus aur eus strain to two types of disposable contact lenses has been carried out. The first type was an ionic!high-water-content (I-HWC) lens (42% Etafilcon A, 58% water) and the second was a non-ionic/low-water-conte nt (NI-LWC) lens (61.4% poly(2-hydroxyethyl methacrylate), 38.6% water ). Adhesion to the two lens types was evaluated both in basic conditio ns and after treatment with lysozyme. The results showed that I-HWC le nses are more prone to Staphylococcus aureus adhesion than NI-LWC lens es, both untreated (+ 15.4%) and treated with lysozyme (+ 20.5%). Lyso zyme increased bacterial adhesion by 30.5% on the lenses with lower wa ter content, and by 36.3% on those with higher water content.