Quantification of Indoor Ocular Exposure to Solar Ultraviolet Light With Four Room Orientations: Using a Model Monitor Embedded in a Manikin Head

Solar ultraviolet (UV) radiation is an unavoidable physical environmental factor that contributes to a variety of eye diseases. Exposure to indoor solar UV radiation is an essential component of individual ocular UV exposure. However, few previous studies have attempted to quantify the exposure in term of indoor solar UV irradiance reaching the surface of the human eye under different exposure conditions. Hence, in the current study, we measured the UV exposure in rooms with four main orientations in Sanya (18.4 degrees N, 109.7 degrees E, the lowest-latitude city in mainland China) and Lhasa (29.7 degrees N, 91.14 degrees E, the highest-elevation city in mainland China) to obtain the general and maximum ocular exposure to indoor solar UV in China. A monitoring model consisting of a dual-channel spectrometer that implanted into the manikin eye was used to quantify the UV exposure at a range of times. This study revealed basic diurnal variations under different indoor exposure conditions. In summary, on a sunny summer day, if a person gazes out of an open window at a distance of 0.5 m away from the window, some danger to the eyes may exist in the solar elevation angle (SEA) range of 12 degrees to 37 degrees in an eastward-facing room and in the SEA range of 34 degrees to 9 degrees in a westward-facing room under the maximum open window UV exposure conditions in Lhasa. Similarly, the accumulated UV exposure in a southward-facing room in Sanya was in the SEA range of 67 degrees to 88 degrees. This study attempted to determine the maximum individual accumulated ocular unweighted UVA dose and biologically effective UV dose (UVBE) to serve as a reference for exposure to Sanya and Lhasa. These results can strengthen the understanding of human ocular health and further clarify the possible risks posed by continuous UV exposure.