The wavelengths of visible light, ultraviolet light, infrared light, and their effects on aging. As indicated in the figure, the wavelength of visible light is between 380 to 720 nm; ultraviolet light is less than 380 nm; infrared light is greater than 720 nm. The effects on aging of ultraviolet light (UV), near-infrared light (NIR), blue light, and visible light are listed briefly in the figure, and explained in further detail in the text.