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Optical radiation encompasses ultraviolet, visible and infrared radiation, and may impact negatively upon the human eye and skin. The effect which results depends upon factors such as the wavelength, the radiation intensity, the duration of exposure, and the characteristic of exposure over time. Positive effects are vision, and the feeling of well-being caused by visible and infrared radiation. The harmful effects include keratitis and conjunctivitis caused by ultraviolet radiation, opacity of the crystalline lens caused by ultraviolet and infrared radiation, retina burns, and photochemical damage to the retina caused by visible radiation. The limit values issued by the ICNIRP (International Commission on Non-Ionizing Radiation Protection) may be employed for risk evaluation. Suitable sunglasses and eye-protection filters must be employed which must be selected carefully in consideration of the visual task, the intensity of the radiation, and its wavelength. |