The most dangerous components of sunlight entering our eyes are the spectra in the Ultra Violet range. Ultra-Violet light is broken down into four parts, referred to as UV-A, UV-B, UV-C and UV-D. They each represent a range of wavelengths of light within Ultra-Violet light. The ability to block 100% of all four parts of Ultra-Violet light is referred to as UV400.
We’ve all experienced glare in our daily lives… perhaps spending the day at the beach, driving in a car with the sun reflecting off the dashboard, roadway or bonnet or on a boat with the sun illuminating the surface of the water. Usually, this glare is annoying and uncomfortable on the eyes, but when the angle of reflection is just right, the glare can become blinding and often downright dangerous, as in the case of driving a vehicle. Ordinary tinted sunglass lenses only cut down on ambient light that reaches the eye, or, light transmittance. By their very nature, they cannot block glare. Only polarised lenses can block out this dangerous, blinding glare. To understand how, you will need to understand how glare works and how polarised lenses work.
