A Thai study to evaluate the bacterial adherence properties of soft contact lenses (CLs) found that HEMA lenses are most suitable for biofilm formation, while hydrogel-based CLs are less supportive of bacterial growth.
Led by microbiologist Dr Auemphon Mordmuang, from Prince of Songkla University, the research team reported that Staphylococcus aureus and Pseudomonas aeruginosa represented the highest biofilm-producing bacteria on printed hydroxyethyl methacrylate (HEMA)-based materials. Printed HEMA CLs “significantly demonstrated more biofilm staining and bacterial attachment when compared with non-printed HEMA CLs, while the filcon II 3 and nesofilcon A (hydrogel) CLs possessed less biofilm biomass and adherent cells.” HEMA-based lenses may also help to sustain the growth of microorganisms in prolonged contact with the cornea, leading to full-blown ocular surface infections or microbial keratitis, they added.
The second part of the study compared the ability of CL-care solutions to remove bacterial film. The researchers tested normal saline solution (NSS), multipurpose solution (MPS), a combination of multipurpose disinfecting solution (MPDS) plus Polyquad and Aldox (PoA), and a combination of MPDS plus edetate disodium and sorbic acid (EDSA). Researchers said that the highest disinfection efficacy was seen with a two-step system of rubbing with Bausch & Lomb’s Sensitive Eyes daily cleaner (MPDS+EDSA) followed by soaking in MPS.