Sunglasses can be divided into three types: Sun mirror, light sun mirror and special purpose sunglasses. The so-called shade mirror, as the name implies is used for shading, people in the sun usually to adjust the size of the pupil to adjust the luminous flux, when the intensity of light over the human eye to adjust the ability, it will cause harm to the eyes.
So in outdoor activities, especially in summer, many people use sun visor to block the sun to reduce the fatigue caused by eye conditioning or the damage caused by strong light stimulation. Light-colored sunglasses are not as good as sun visor, but their color is rich, suitable for use with all kinds of clothing, there is a strong decorative role. Light-colored sunglasses because of its rich color, diverse styles, by the young people of all ages, fashionable women to it is more dote on.
Special-purpose sunglasses have a strong shielding of the sun's function, often used in the beach, skiing, mountain climbing, golf, such as the sun is strong in the wild, and its anti-ultraviolet performance indicators have higher requirements. Different groups of people, according to different preferences and different uses to choose sunglasses, but the most fundamental thing is to be able to protect the wearer's safety and vision without damage to the basic principles. The basic function of the sunglasses is to reduce the intensity of light stimulation, the apparent deformation of the sight, the ultraviolet protection, the true recognition of the color and the accurate identification of traffic signals. If the above function is defective, light is lost the role of sunglasses, heavy will produce dizziness, eyes, such as acid swelling consciously do not adapt to symptoms, and sometimes will produce unresponsive, color illusion and walk as the symptoms of inequality and cause traffic accidents. Therefore, the choice of sunglasses can not only focus on the style and ignore its intrinsic quality.