[Development of a monitor for quantifying personal eye exposure to visible and ultraviolet radiation and its application in epidemiology].

Eye diseases including cataract, keratitis and pterygium have been reported to be sun-exposure-related. The association between macular degeneration and blue light has also been discussed. Moreover, it is hypothesized that retinal exposure to blue light may influence the human circadian rhythm. However, no monitoring devices exist that can measure eye exposure to visible and ultraviolet (UV) radiation over time. To measure the exact dose at specific times, we have developed a novel sensing system (ray-sensing glass system: RaySeG). RaySeG can continuously measure and record the composition and intensity of light with a time-stamped system. Subjects wearing RaySeG were instructed to walk under various light conditions such as indoor and outdoor. RaySeG consists of two sensors embedded in the eyeglasses. These sensors are for UV (260-400 nm), visible lights (red, 615 nm; green, 540 nm; and blue, 465 nm: peak wavelength for each). The total weight of the system is about 100 g, and the size is comparable to that of a digital audio player. The system continuously recorded changes in visible and UV light exposure under various conditions. After accuracy validation, further experiments with a larger number of subjects are required. Our final goal is to apply the system to evaluating personal eye exposure to UV and visible light in epidemiological studies of eye diseases and circadian rhythm abnormality.