Automated Sunglasses Lens Exposure Station and the Preliminary Effects of Solar Exposure

The Laboratory of Ophthalmic Instrumentation (LIO) from the University of Sao Paulo—Brazil, is involved in research about Sunglasses and its standards, and has already contributed for changing parameters in the previous Brazilian sunglasses standard, the ABNT NBR 15111-2013. The focus of the work presented in this paper is to investigate on the long-term solar exposure effects in sunglasses lenses and to conduct this study, we have developed an automated exposure system dedicated to expose sunglasses lenses towards the sun. The system also measures the dose of ultraviolet radiation which the lenses were subjected to and other weather variables, like temperature and relative humidity of the air. In this paper, we discuss about the materials used to manufacture sunglasses lenses, about the machine we developed to exposes the lenses and the methods used to measure the lenses transmittance characteristics over the time and to determine if and how long-term solar exposure may affect the samples.