How to choose sunglasses

　　1. Choose brown and brown lenses. In summer, it is best to choose brown and brown lenses, because these lenses are better at absorbing and filtering UV rays. Brown lenses block radiant light from smooth, shiny surfaces and allow subtle parts of objects to be seen in harsh sunlight, while brown lenses distinguish colors in bright light.

　　2. Choose sunglasses with sun protection. Look for the "UV400" logo when choosing sunglasses, because the UV wavelength is below 400 nanometers, which indicates protection against UV rays. Some products will have a label such as "Blocks all UV rays". Such sunglasses can protect the eyes.

　　3. Identify the quality of lenses. The surface of a qualified lens should be smooth, without ripples, flaws, abrasion marks, and bubbles. Before wearing sunglasses, observe objects in red, green, yellow and other colors, and then observe the same objects after wearing. Place your sunglasses in front of your eyes, look through the lenses for distant targets, and then move them up and down so that the targets don't swing or bend.

　　4. How to choose sunglasses for drivers. Sunglasses should not be too large or heavy, as they will make the driver uncomfortable to wear and easily distract from driving. Lenses should not be too dark colors, because dark lenses will delay the transmission of visual signals to the brain, affect the driver's judgment of speed, and are prone to errors.