ULTRAVIOLET DISINFECTION OF CONTACT-LENSES

To evaluate the efficacy of ultraviolet (UV) radiation as a method of disinfecting contact lenses and their storage solutions, we contaminat ed soft lenses (Bausch & Lomb Optima 38), rigid gas permeable (RGP) le nses (Oxyflow F-30), and their storage solutions with three common bac teria, Escherichia coli (E.c.), Staphylococcus epidermis (S.e.), and S erratia marcescens (S.m.). The storage solutions used were saline solu tion and RGP conditioning solution. We determined the exposure times t o 253.7-nm wavelength UV radiation necessary to disinfect the contact lenses and solutions. The decimal reduction values (D values) found fo r UV radiation were 10 to 200 hundred times shorter than reported for currently available disinfection systems. For E.c., sterilization was attained after 100 s of exposure. For S.e. and S.m., sterilization occ urred after 300 s of exposure. Different contact lens solutions transm it UV radiation to various degrees, with saline solution passing more than 90% of the UV radiation. Thus, our results indicate that UV radia tion is an effective and rapid method of disinfecting contact lenses a nd their storage solutions.