Sunglasses by purpose can generally be divided into the visor mirrors, light colored sunglasses and special purpose sunglasses in three categories.
So-called visor mirrors, as the name suggests is used as a shade, who is usually in the Sun by adjusting the size of the pupil to regulate the luminous flux, when light intensity exceeds the adjustment ability of the human eye, can cause harm to the human eye. Places for outdoors activities, especially during the summer, many people used the visor mirror to block the Sun to reduce eye fatigue caused by regulation or the damage caused by light stimulation.
Light colored sunglasses on the blocking of sunlight than the visor mirrors, but their rich colors, suitable for use with all kinds of costumes, there is a strong decorative effect. Light colored sunglasses due to their rich colors, various styles, by young people of all ages, women have added to their love of fashion. Special purpose sunglasses with strong blocking sunlight feature, commonly used for Beach, ski, climbing, golf and other strong sunlight field, its resistance to UV index have higher requirements. Different groups of people, according to different tastes and different uses to choose sunglasses, but the most fundamental is to protect the wearer's safety and vision do not damage the principle. Reduced light stimulation, depending on the matter is clear and no deformation, UV, color distortion, accurate identification of traffic signals, should be the basic function of sunglasses. If the above function is flawed, ranging from lost sunglasses, while consciously does not fit symptoms such as dizziness, eye swelling, sometimes slow to react, debate-color illusion and walking symptoms see inequality and causing traffic accidents. Choosing sunglasses should not only focus on style rather than its intrinsic quality.