title: Efficacy of multipurpose solutions for rigid gas permeable lenses.
abstract: The use of multipurpose solutions for cleaning and disinfecting rigid gas permeable lenses has replaced single purpose solutions, but there are no reports of the efficacy of these multipurpose solutions, or of the effects of storage conditions on their disinfecting capacities. This study investigated activity against four bacterial and two fungal species, and the effects of storage in a refrigerator, at room temperature, at elevated temperature in both dry and humid conditions and with exposure to sunlight. The disinfecting solutions were challenged with the micro-organisms initially upon opening and then at 2-weekly intervals up to 12 weeks after being stored under the different conditions. Solutions were opened daily to simulate use. One solution failed to meet Food and Drug Administration (FDA) criteria to reduce numbers of bacteria by three log dilutions and of fungi by one log dilution. Storage reduced activity of all solutions over the 12-week period, but not below the requirements of the FDA. Storage in the refrigerator tended to reduce disinfecting capacity more quickly. Multipurpose solutions for rigid gas permeable (RGP) lenses lose activity over the 3 months recommended time of use but remain satisfactory for use over this time in the conditions tested. Practitioners need to remind patients to replace their solutions regularly and should advise against storage in the refrigerator. Multipurpose solutions for RGP lenses have simplified cleaning and disinfecting processes and the current formulations have improved disinfecting capacity compared to former disinfecting solutions, which is particularly important for wearers of orthokeratology lenses.
authors.affiliation: Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China. htmboost@inet.polyu.edu.hk
authors.forename: Maureen
authors.initials: M
authors.lastname: Boost
authors.forename: Pauline
authors.initials: P
authors.lastname: Cho
authors.forename: Sindy
authors.initials: S
authors.lastname: Lai
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects / Q000302:isolation & purification; D018639:Contact Lens Solutions / Q000494:pharmacology*; D003261:Contact Lenses / Q000382:microbiology*; D004203:Disinfection / Q000379:methods*; D004356:Drug Storage; D004867:Equipment Design; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification; D005670:Fusarium / Q000187:drug effects / Q000302:isolation & purification; D006801:Humans; D006813:Humidity / Q000009:adverse effects; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification; D012706:Serratia marcescens / Q000187:drug effects / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification; D013472:Sunlight / Q000009:adverse effects; D013696:Temperature; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D018639:Contact Lens Solutions