Risk of Ocular Exposure to Biologically Effective UV Radiation in Different Geographical Directions

To quantify ocular exposure to solar ultraviolet radiation (UVR) and to assess the risk of eye damage in different geographical directions due to UVR exposure, we used a spectrometer and a manikin to measure horizontal ambient and ocular exposure UVR in different geographical directions at four different locations at the Northern Hemisphere. Describing the relationship of exposure to risk of eye damage requires the availability of UV hazard weighting function. So, we used the UV hazard weighting function (ICNIRP) proposed by International Commission on Non-Ionizing Radiation Protection to determine the biologically effective UV irradiance (UVBEeye) and then cumulative effective radiant exposure (H-eye) to shown the risk of eye. We found that in different geographical directions, distributions of ocular exposure to UVR were markedly different from those of horizontal ambient UVR. When the midday maximum SEA>50 degrees, eye received more UVR from the east and west directions during the morning and evening hours, respectively. However, when the midday maximum SEA<50 degrees, eye received more UVR from the south direction at noon. The results of this research indicate that the higher risk of eye caused by UVR varies according to the midday maximum SEA corresponding to different geographical direction.