What does 1 Category 2, Category 3 and Category 4 on the sunglasses tag mean?

Refers to the transmittance of lenses, which can be divided into 1, 2, 3 and 4 categories. Divided into: light-colored sunglasses, umbrellas and special-purpose sunglasses.

According to the standard, the transmittance of sunglasses is divided into four grades, and the higher the grade, the higher the light blocking rate.

Precautions:

In order to prevent the harm of wearing sunglasses to eyes and face, try not to wear sunglasses at unnecessary times and occasions; When you need to wear it when going out or in the sun, it is best to control the time within 2~3 hours.

Extended data

Sunglasses, also known as sunglasses, are used for shading. People usually adjust the luminous flux by adjusting the pupil size in the sun. When the light intensity exceeds the adjustment ability of human eyes, it will do harm to human eyes.

Therefore, in outdoor activities, especially in summer, it is necessary to use parasols to block the sun, so as to reduce the fatigue caused by eye adjustment or the damage caused by strong light stimulation.

reference data

Sunglasses _ Baidu Encyclopedia