EFFECTS OF ULTRAVIOLET-RADIATION ON CONTACT-LENS PARAMETERS

Ultraviolet (UV) radiation has been proposed as an alternative method for contact lens disinfection. In order for UV radiation to be conside red a viable contact lens disinfection method, its effects on lens pol ymers and parameters must be minimal. To evaluate this, soft contact l enses from each of the four FDA categories, soft lenses with handling tints, and rigid gas permeable (RGP) lenses were exposed to UV radiati on in a controlled laboratory setting and their parameters measured. A fter 20 h of UV exposure, we found statistically significant changes i n at least one parameter for each lens type evaluated. Most of these c hanges were small and within the error of measurement and, therefore, were not considered clinically significant. However, the group 2 soft lenses showed an increase in all four measured parameters-power, cente r thickness, diameter, and water content. These changes may have an im pact on lens fitting characteristics and performance. Other than these changes for group 2 soft lenses, 20 h of UV exposure appeared to have little clinical effect on the contact lenses evaluated. This suggests that UV radiation may prove to be a feasible alternative method of di sinfection for most types of contact lenses.