Sunglasses light transmittance

For light colored sunglasses, their light transmittance should be>40%; For sunshades, the range of light transmittance is 8% to 40%. The light transmittance is an important indicator of the function of sunglasses. The current Chinese standards classify sunglasses into three categories based on this function: sunshades, light colored sunglasses, and special purpose sunglasses, while European and international standards classify them into five categories.
The use of sunglasses varies depending on the category. If light colored sunglasses are used for shading, the wearer will not be able to achieve good shading effects, such as prolonged outdoor activities in strong sunlight, and the wearer will still feel tired due to the stimulation of strong light. Light colored sunglasses are generally used for decorative purposes or in indoor environments with less intense sunlight. On the contrary, wearing sunshades indoors or in places where strong sunlight is not necessary can cause discomfort and fatigue due to excessive dilation of the pupils. In sunshades, products with low transmittance are not suitable for cyclists or drivers to wear, as cyclists or drivers travel faster than pedestrians, and a low transmittance can affect their reaction ability.