## First Tip Sunglasses should have a UV filter. Sun rays are not only blinding, but they also promote the formation of free radicals, which destroy healthy cells. The UV rays do the most damage to the crystalline lens. The consequences can be very serious, ranging from dry eyes to cataracts. You can see the level of UV protection on the label of the sunglasses. Good sunglasses should provide UV 400 protection. ## Second Tip Plastic lenses protect your eyes better than glass ones. The best materials include acrylic or polycarbonate, which prevents both A and B UV rays from getting into the retina. Additionally, plastic sunglasses are more comfortable and last longer. ## Third Tip Whatever color you choose for the lenses, they should be uniform. The popular choice of when the top of the lens is darker than the bottom provides poor protection from sunlight, as the sun rays get into your eyes not only from the top but are also reflected from surfaces. ## Fourth Tip Don't buy lenses that are too dark. In addition to reducing your vision, overly dark lenses make the pupils dilate so that the eyes get more UV rays than in glasses with lighter lenses. ## Fifth Tip It is recommended to pick the color of the lenses according to the climate zone and the purpose of wearing the glasses. For daily wear in the city, any color would work, although grey or green tint are considered optimal since your eyes will be less tired. If you are near the ocean or in the mountains where there is a lot of sunlight, it is advisable to choose polarized glasses that reduce glare and make objects look sharper without straining your eyes. ## Sixth Tip If you are short or long-sighted, your sunglasses should have dioptric lenses. Many people prefer glasses with chameleon lenses that darken in the sunlight and lighten indoors, but ophthalmologists don't recommend these. It is better to have a separate pair of sunglasses since chameleon lenses provide poor protection from UV rays. ## Seventh Tip People choose the shape of sunglasses based on their liking and their face types. You should remember that the shape you choose should fit your face as close as possible. If you don't, the sun rays from the top, bottom, and sides will injure your eyes, making the sunglasses useless. ## Eighth Tip If you have any vision issues, you should choose sunglasses with your doctor's advice. The wrong sunglasses can make your condition worse, so it is important to discuss the color, degree of darkness, and other characteristics with a specialist. Don't rely only on salespeople.