Sunglasses buying guide. ( A)

Popular science according to the optical society of America's web site, small make up translation summarizes this sunglasses buying guide, very informative, you need. Recommended reading: sunglasses exposure happened after 50 hours first, people should wear sunglasses in outdoor activities, whether in work, drive, or in sports, walking, running. Why need sunglasses? Uv filter. The sun's ultraviolet ( UV） Radiation can cause human cataracts, pterygium, eyelid skin cancer and electro-optic ophthalmia ( Also known as snow blindness, is the cornea injury) 。 Wide-brimmed hat can block ultraviolet light of 50% to the eye, so you also need to wear sunglasses. Filtering blu-ray: long exposure to uv and blue light frequency, is the old age in age-related macular degeneration ( AMD) Risk factors of the disease. ( Small make up added: age-related macular degeneration, the prevalence of 12 europeans. 3%, Asian prevalence 7. 4%,万灵王,柳叶刀全球卫生,2014) Comfortable feeling: bright and dazzling sunlight can let an eye uncomfortable, depending on the impact of clarity, people will squint and tears. Strengthen the dark adaptation: 2 - in the bright sunlight After three hours, people on indoor lighting and adaptability will reduce in the night, lead to drive at night is more dangerous. The basic requirement of sunglasses: stop - 99 100% of UVA and UVB rays; 75 - 90% of visible light; Depending on the both absorb ultraviolet light, and does not cause distortion and distortion; Don't misled by fake UV filtering logo ( Lenses 100% UV absorption or UV400 labelling) 。 In order to ensure that the label is true, the best lens UV filtering performance can be detected in the store to buy sunglasses, or buy from formal channels. Small make up comment on: when I was in Beijing, a little nurse bought fake D& in the field of; G sunglasses, wearing a walking dizzy and sick. This suggests that the fake lens dioptre is not zero. Lens color uniform, a region not dimmed. If it is a gradient lens, lens color should be from the top down gradually becomes shallow. Wear sunglasses when driving should be gray, Gray, smoke gray, celadon) , this does not affect to distinguish the color of the traffic lights. Make sure the lens distortion does not produce vision. Take sunglasses, unbend arm, through the lens look into the distance of right Angle or a straight line ( Such as doors, Windows) 。 Picture frame, slowly moving up and down or so, if there is a distortion, deflection, bending, distortion, suggesting that vision lenses with optical defects, is not qualified. To ensure that sufficient optical lenses can stop in front of the mirror to try. If the lens is easy to see through my eyes, that the color of the sunglasses are dark enough. Note: this method is not suitable for color lenses. The weight of the sunglasses evenly distributed on the nose and ears. Careful adjustment of the radian of frames and nose position, picture frame not pinch the bridge of the nose, nor ears. When wearing, eyelash not exposed picture frame. Polarized sunglasses can reduce glare, used for level of highway and water, ice and snow. While driving, skiing, water skiing, golf, ride a bike when wearing. Cataract surgery, and sensitivity to the elderly, choose the polarized sunglasses can improve visual comfort. Drive note, polarized glasses, will can't see the car LED display, GPS and mobile phone screen, ATM and pumps of the digital display, etc. Recommendation: yellow, brown, green, can filter blue light. Polarized sunglasses can not be used in flight. In some sports, such as playing golf, wear polarized sunglasses may cause part of visual information loss, impact performance. Color sunglasses myopia people like the convenience of color sunglasses, the color of the lens with the strength of the light and darker or lighter. Just, when enter indoor or outdoor environment, the lens was not immediately become angry. Car windshields can interfere with the lens color, so in less effective when driving. In a cold environment, the lens color change is slow. Sometimes indoor light is too strong, the lens color is dark, looks very strange. Color change after the lens is not dark, especially in the sand, snow, water sports, such as sunlight intense environment, cannot replace the sunglasses, can't bring enough visual comfort. Mirror surface sunglasses one-way mirror oh. The police's uncle like it very much! So each other can't see the eyes of the police and expression, be helpful for self protection. Mirror reflective coating color variety, this is determined by the thickness of the coating and the structure, and the feeling of the wearer is not colorful, usually brown or gray. Reflective coating will reduce 10 - 60% through the lens of the light, and therefore very suitable for desert, sea lake, snow snow mountain and high altitudes. Is very popular in the extreme sports. 吗? 吗?