Quantification of Ocular Biologically Effective UV Exposure for Different Rotation Angle Ranges Based on Data from a Manikin

Human outdoor activities are randomly orientated at different angles to the sun. To quantify the ocular UV and biologically effective UV ( UVBE ; i.e. the ocular UV irradiance exposure for photokeratitis ( UV pker), photoconjunctivitis ( UV pcon), and cataract ( UV cat)) exposure for different rotation angle ranges, a rotating manikin was used to monitor the ocular UV exposure at different rotation angles in clear skies during July 2010 in Sanya, China. As a result, the ocular UV and UVBE irradiance was directly influenced by the rotation angle variations, primarily for the 120° rotation angle ranges facing the morning and afternoon sun when the solar elevation was lower than 60°; during these times, the UV and UVBE spectral irradiance decreased as the rotation angle increased. When compared to the 360° rotation angle ranges (which were considered to be the average exposure situation), the cumulative ocular UVBE for 60°, 120° and 180° rotation angle ranges were maximally 91% ( UV cat), 94% ( UV pker) and 121% ( UV pcon); 71% ( UV cat), 74% ( UV pker) and 95% ( UV pcon); 42%( UV cat), 45%( UV pker) and 55% ( UV pcon) higher respectively. Meanwhile, the cumulative ocular UVBE for the 180° rotation angle ranges facing away from the sun were 46% ( UV pker), 59% ( UV pcon) and 45% ( UV cat) lower.