Try wearing sunglasses to see if you feel dizzy or have a headache. At present, there are some myopia sunglasses with degrees on the market, but because the pupil distance and other indicators vary from person to person, consumers had better not choose these sunglasses with degrees without professional guidance.
3. Hold the two corners of the sunglasses with both hands, face the fluorescent lamp, and let the reflective strip of the mirror roll gently. If you find that the shadow of the fluorescent lamp reflected by the mirror is wavy and twisted, it proves that the lens is uneven, and such a mirror will damage your vision.
4. The lens should be flat and transparent. The materials of sunglasses are glass and resin, and the best sunglasses should be polarized lenses. It is made of light and precise synthetic resin like contact lenses, and consists of seven thin layers, the outermost two of which are superhard wear-resistant layers; The second layer and the sixth layer are shatterproof reinforcement layers; The third and fifth layers are ultraviolet filter layers, and the middle layer is polarization filter layer. Polarized lenses can effectively filter reflected light and harmful ultraviolet rays, and have the functions of shatterproof and wear resistance, so they are the most popular sunglasses.
The main purpose of wearing sunglasses is not only to reduce strong light stimulation and make eyes comfortable, but also to prevent ultraviolet rays from hurting eyes. The color of the lens and whether it protects against ultraviolet rays are two different things. Even if the color of the lens is dark, it may not be able to effectively prevent ultraviolet rays, so be sure to choose the lens marked with anti-ultraviolet function. Usually the UV index of sunglasses is between 96% and 98%.
6. Learn to understand product identification.
Not all sunglasses have anti-ultraviolet function. A pair of sunglasses that meet the basic requirements of the standard can only be said to block strong light and not transmit more ultraviolet rays. If a pair of sunglasses can only block strong light but not the same amount of ultraviolet rays, then the wearer will receive more ultraviolet rays than without sunglasses (wearing sunglasses will reduce the flux into people's eyes and lead to the wearer's pupil enlargement). Sunglasses sold on the counter in shops generally have obvious signs on their lenses, tags or packages, just like the fabric components on clothes, so consumers must carefully check them when buying.
Whether a pair of sunglasses has anti-ultraviolet function is indistinguishable to the naked eye. The manufacturer's clear commitment to the product is the only reference for consumers to buy sunglasses with protective function. We can see clear signs such as "100% UV protection", "UV400", "block all ultraviolet rays" and "UV protection" on the labels of some products and the front of glasses.
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