As summer approaches, we hear about people who have broken their skin due to sunburns in the sun, and more and more outpatients who come to the clinic with “sunburned” eyes after visiting the beach because their eyes are very painful. UV damage to the eyes is divided into acute and chronic. Acute injury is instant exposure to very strong ultraviolet sunlight, such as snow or beach, this type of injury is very strong, in three to six hours will damage the cornea, the patient will have pain, tears and eyes can not open and other symptoms. Chronic damage is the cumulative exposure over the years in an environment full of ultraviolet light, but did not do a good job of preventive measures, such as farmers and fishermen work for a long time in the field or at sea, may only wear a hat for simple sun protection, over time there will be chronic changes such as cataracts, crystal body will absorb ultraviolet light becomes more cloudy, but also easy to appear winged flab. In addition to umbrellas, hats, etc. can shade, sunglasses are the best weapon against UV rays. Sunglasses can prevent ultraviolet radiation, but also can show personality, by the young family’s favor, fashionable women are more favorable to it, for the necessary things when going out, but for the knowledge of sunglasses, you know how much it? Sunglasses according to the use of general can be divided into sun glasses, light-colored sunglasses and special purpose sunglasses three categories. Sun shades, as the name implies is used for shading, people in the sun usually rely on adjusting the size of the pupil to adjust the amount of light flux, when the light intensity exceeds the ability of the human eye adjustment, it will cause harm to the human eye. So in outdoor places, especially in the summer, many people are using sun shades to block the sun to reduce eye fatigue caused by regulation or injury caused by bright light stimulation. Light-colored sunglasses on the sun’s light blocking effect is not as good as sun shades, but its colorful, suitable for use with all kinds of clothing, has a strong decorative role. Special purpose sunglasses with strong sunlight blocking function, commonly used in the beach, skiing, climbing and other strong sunlight in the field, its anti-UV performance and other indicators have higher requirements. According to the material characteristics of sunglasses can be divided into two categories of absorbent and reflective. Absorption sunglasses are in the glass plus some heavy metal oxides, this lens can selectively filter out some harmful light. And reflective lenses are based on the light reflective properties of the mirror coating, the harmful light will be reflected out to protect the eyes from harm. Consumers in the purchase of sunglasses in addition to considering personal preferences such as style factors, be sure to pay attention to the following points: 1, should choose a good strength of the lens to prevent damage to the eyes when broken, it is generally recommended to use resin lenses. 2, optional sunglasses are best to choose gray lenses, gray is neutral, it can be red, orange, yellow, green, blue, purple and other seven-color ratio diminished, wear a cloudy feeling. Followed by green, brown, teal green, teal, etc.. Sunglasses should not be too dark in color, otherwise it will make the pupil dilated and more UV rays will be shot in. Lenses that are too red or too blue are not good for the eyes. To make sunglasses can effectively block the summer glare, the color of the glasses should have enough depth, but cyclists or motorists, do not choose the color too dark lenses. 3, when buying should pay attention to check the UV label on the lens. According to F・D・A standard, the lens to protect the light transmission at the same time, to filter out more than 90% of the sun’s ultraviolet rays, the lens should be labeled “UV- 100PROTCT10N”, when 100% filtered UV, should be labeled “UV- 400PROTCT10N “label. 4, often cyclists are best to wear resin sunglasses; sports wear frame curved sports sunglasses or add a band, chain; myopic or farsighted people, can wear sun lens clip or wear special optical sunglasses. In addition, spring and autumn, choose lighter lenses, frame color stable sunglasses; winter frame color to choose some gorgeous, snowy days to wear color film sports sunglasses, winter choose frame shape slightly larger sunglasses in order to wind 5, should develop good sunglasses wearing habits, otherwise the lighter easy discomfort, the heavier suffer from eye disease. For example, there is no need to wear sunglasses on cloudy days and indoors. Some people regardless of the occasion, regardless of the sunlight intensity, even at dusk, evening and in watching movies, TV also wear sunglasses, which will instead increase the burden of eye regulation, causing eye muscle tension and fatigue, so that vision loss, blurred vision, serious dizziness, can not be long vision and other symptoms, medically known as sunglasses syndrome. This disease is reflected in a variety of discomfort, such as early in the eyes near the nose area has a distinct numbness and tingling, breathing symptoms are more obvious, very similar to the flu, and people feel like there are small bugs crawling away in the face, the upper jaw gums numbness, upper incisors feel discomfort, poor local blood circulation caused by skin inflammation, eye soreness, vision loss. These discomforts, mostly appear after 2-3 weeks of wearing sunglasses. Once the symptoms of sunglasses syndrome, should stop wearing them, and in serious cases should also go to the ophthalmology consultation.