The sunglass lens tint reduces visible light and provides effective protection against sun glare. Renowned manufacturers ranked lenses into different categories depending on light conditions. To find the category to which a pair of sunglasses belongs, you just look at the interior of the frame. Ranking ranges from 0 to 4 according to European standards:
Category 0: Passes 80% to 100% of brightness. Clear or slightly tinted, perfect for indoors and outdoors with cloudy weather.
Category 1: Passes 43% to 80% of brightness. Slightly tinted glasses: the perception of the luminosity is reduced. Good for cloudy days and in the city.
Category 2: Passes 18% to 43% of brightness. Moderately tinted lenses: light perception average. Particularly suitable for summer.
Category 3: Let go 8% to 18% brightness. Dark glasses: strong sunlight. Very suitable for southern climates, water reflections, beaches and mountains.
Category 4: Passes 3% to 18% light. Very dark glasses: exceptional solar luminosity (not recommended for driving). Ideal for high mountains and glaciers.
UV filtering occurs through appropriate lenses regardless of the level of “darkness” of the tint. It’s not necessarily the darkest glasses that best protect the eyes, but sunglass lenses made with materials of high quality, high capacity UV-ray filters.
The sunglasses with the CE mark comply with all requirements and directives, and provide adequate ultraviolet ray protection for the eyes. The CE mark often etched to the inside of the frame and more specifically to one arm of the sunglass frame, shows compliance with safety requirements in accordance with EU directives. There is no independent body that inspects each model individually. However, the famous manufacturers of glasses are often voluntarily complying with these standards due to their desire to preserve their global standing and to keep their reputation intact. You can also check for yourself the validity of that mark by consulting an expert in the optical world or simply an optician.