Pay attention to the six main points when purchasing sunglasses in summer
Dr. Wei Ruihua, an ophthalmologist, and Dr. Guo Junlai, who has extensive experience in optometry, reminded people that when purchasing sunglasses, they should first look at the UV protection and glare functions of the mirror, and then look at the style and price. Specific attention should be paid to the following six points: Is not equal to 1. colored glasses sunglasses, UV recognize identification The UV wavelength is below 400 nm. When choosing sunglasses, you should recognize the "UV400" logo. This logo indicates that it is resistant to UV rays. Some sunglasses will be labeled "UV protection" or "100% UV protection", which also indicates that they have UV protection. Do not buy without such a logo. There are many colored glasses on the market, and many people think that as long as the glasses have the color to block the sun, it is sunglasses. Actually, this is a misunderstanding. UV protection and glare are the two most important functions of sunglasses. The role of lens color is mainly to block the glare, so that people can see things without glare, and whether the lens can prevent UV and color has nothing to do, mainly depends on the lens material and coating. If the picture is only beautiful or cheap, buy a pair of colored glasses without UV protection, which is more harmful than not wearing a mirror. Because the human body has a self-protection reaction, when the eyes are exposed to strong light, the pupil will naturally shrink, so that the ultraviolet rays entering the eyes are reduced. However, if colored glasses with no UV protection function are worn, the light intensity received by the eyes is weakened, and the pupils are enlarged. UV intrusion. 2. The color depth of the lens is preferably moderate. If the lens is too light, the function of blocking the glare will be weakened. If it is active in the sun, it will still feel irritating. If the lens is too dark, it will affect the object and even interfere with the true color of the object, and the traffic signal can not be distinguished. Generally, medium-depth color sunglasses can meet people's daily needs. 3. The specific color of the lens should not affect the true color of the object, ensuring comfortable eyes. There are many sunglasses lenses on the market, mainly brown, gray, and green, but also red, yellow, and so on. The reason why strong sunlight makes people look uncomfortable is mainly related to the stimulation of the eyes by Huang Guang. Generally, brown, gray, and green lenses have a strong blocking ability against yellow light. The specific color can be determined according to personal preference, but no matter which color lens is chosen, it should be based on the principle that the color of the object is not distorted, the traffic signal can be effectively recognized, and the eyes feel comfortable. 4. The surface of the lens is smooth, no ripples, bubbles, wear marks, and the object is not deformed. Sunglasses are flat mirrors, and the lens surface treatment, curvature, and diopter have strict standards, especially the diopter should be within 0.008. Only in this way can we see that things are not deformed. Otherwise, wearing sunglasses with excessive diopter will feel discomfort, dizziness, etc. A simple way to judge the quality of the lens is to slowly move the glasses up and down and left and right in front of the eyes. If the object is deformed by the lens, it is best to look at the line objects such as panes and door frames. If the lines are curved, the lens diopter is unqualified and should not be selected. purchase. In addition, it should also be noted that the lens surface is smooth, there should be no ripples, bubbles, and wear marks. 5. The frame is not too big. The current large frame sunglasses are very popular and are popular among young people. However, the size and style of the glasses should be based on the individual's eyes and face. In general, as long as the lens can cover the eyes and completely block the sunlight, there is no need to chase the sunglasses with a very large frame. Sunglasses are too large, and the wide frame will oppress the underarms of the trigeminal nerve. Generally, after wearing this type of glasses for 1 to 2 weeks, it will cause sore eyes, numbness in the eyelids or between the cheeks, and unconsciousness such as slowness of consciousness, which is unfavorable to eye health. 6. Crystal mirror can not prevent UV The brown crystal glasses sold in street stalls or small shops are popular among middle-aged and old friends. They think that wearing this crystal glasses is very eye-catching. In fact, crystal glasses do not have any UV protection, and must not be used as sunglasses. 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