Prizm High Intensity Pink Iridium is an optimum lens for snowy and cloudy days with a tint that increases depth perception and contrast on the mountain. The Iridium coating reduces glare from sunlight reflecting off the snow. Prizm technology blocks specific wavelengths of light whilst boosting others to provide maximum contrast and enhanced visibility. This greater clarity results in reduced reaction times and increased performance over a wide range of light conditions.Visual Light Transmission, VLT, refers to the amount of light that penetrates a lens. A low percentage means less light passes through and a higher percentage lets an increased amount of light through. A lens with a lower VLT rating is better for bright conditions; where as one with a higher VLT is more suited for overcast and snowy days.