2. Different Wavelengths

The light differs between infrared, visible spectrum and invisible spectrum depending on the wavelength. The visible spectrum is between 400 nm and 700 nm, with below 400 nm the dreaded ultra violet rays: UVA, UVB and UVC. They are the most energetic rays and the most harmful for both the skin and the eyes. Some sunglasses only protect up to 380 nm however the latest generation of lenses, such as those developed by the brands Polaroid or RayBan ensure protection up to 400 nm.
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