Mathematical Model Of Human Ocular UV Exposure Quantitative

PrefaceAfter the major environmental issue of ozone depletion, the UV-induced climate change, such as skin cancer and cataracts, these two major public health problems aroused widespread social concern. A large number of epidemiological studies and UV exposure assessment surveys have pointed out that UV is an important risk factor of cataract. Accurate quantification of ocular UV exposure dose is the key of evaluation UV-induced cataract risk. As a large number factors affect ocular UV exposure, including the solar elevation angle, altitude, ground reflection, sky scattering and facial anatomy etc, so individual ocular UV exposure quantification has been severely limited for a long time. In fact, when individuals were exposed to natural UV radiation field, not only related to their face direction, also influenced by the eyes, eyebrow, nose and cheek and other facial structure. In addition, people also have strong sunlight active avoidance instinct, just because of these complex factors also limited the precise evaluation of ocular UV exposure dose, it has become the bottleneck of research and prevention of UV-related cataract.To solve this problem, as the starting point of eyes towards all orientation equal probability of one's life for research, we developed a rotating model of ocular UV exposure. In this study, we used this model field monitoring in Sanya area, where the solar elevation angle highest value can reach 90°, to obtain the ocular UV exposure distribution during the day. According to the solar altitude angle and eye angle relationship between the geometric optics when eyes receiving ultraviolet, combined with environmental UV radiation levels, used field monitoring data as the basis for amendments, establishing the mathematical model which can be used to calculate individual ocular UV cumulative exposure doses. This model took into account regional changes and outdoor activity forms, converted environmental UV radiation dose into the ocular, which can replace the eye rotational field monitoring. The mathematical model can more accurately and convenient evaluate the crowd ocular UV exposure dose, providing the basis of prediction and evaluation of eye cataracts risk caused by UV exposure dose objectively and accurately.Methods1. Choosing one week respectively when solar altitude angle is highest and lowest in Sanya city. We monitored the on-the-spot with the individual rotating model of UV in the sunny day, then drew the curve chart from gained data. We can get the change regular pattern of ocular UV exposure during the day.2. Analyzed the geometrical optics characteristics of ocular when the eyes exposure to the UV. Utilized the calculating method of the amount of environment UV radiation translating into the ocular UV exposure, to establish the mathematical model of ocular UV exposure dose, by introducing the adjustment parameter.3. Comparing the ocular UV exposure dose calculated from mathematical model and the actual monitoring results, then analyze and check out the accuracy of mathematical model.Results1. UV radiation through two environmental calculation method comparison,to obtain more accurate quantitative of UV radiation environment,as the basic formula of mathematical model of human ocular UV exposure quantitative. Compare the better environmental calculation with the measured data,they were basically the same.2. According to the human body static ocular UV exposure of optical characteristics, introduce two parameters UFOV and Ee, initial establish human ocular UV exposure instantaneous intensity. Compare the mathematical model theoretical results with the monitoring data, both are consistent.3. According to the human body dynamic ocular UV exposure of optical characteristics, establish human eye exposure to UV cumulative dose of mathematical models, then edit computer programs. Through verified, the mathematical model is accurate and feasible, can be used to assess other areas exposed to the crowd during the day cumulative dose of UV eye.4. Through mathematical model, solar elevation angle is the main factor of ocular UV exposure, the maximum amount of ocular UV exposure appears at the time of the solar elevation angle 40°around.Conclusions1. Established the eye quantitative mathematical model of UV exposure:2. In this study, ocular UV exposure through the eye model calculated instantaneous intensity:in the solar elevation angle 40°around, the ocular UV exposure is the largest.3. The ocular UV exposure mathematical model is proved to be accurate and feasible, edit to a computer software program, for the prediction and assessment of the ocular UV exposure cumulative doses at other areas.