Teach you how to choose the right sunglasses

　　1. Don’t choose sunglasses that don’t protect against UV rays

　　Have you ever had fun buying a pair of sunglasses at a roadside shop? Those low-quality sunglasses that don’t protect against UV rays are worse than not wearing them at all.

　　Wearing sunglasses is to protect against light and ultraviolet rays Eye First of all, shading can prevent headaches caused by dazzling light; secondly, if ultraviolet rays in the sun enter the retina, it will cause macular degeneration and even cataracts and other eye diseases. disease . Inferior sunglasses only use colored lenses to block light, and people's pupils will naturally enlarge in low light. However, inferior sunglasses lenses do not have the function of preventing ultraviolet rays. The enlarged pupils will absorb more ultraviolet rays, which can easily cause cataracts, solar keratitis, corneal endothelial damage, macular degeneration and other diseases.

　　2. The color of sunglasses is preferably dark gray.

　　Wearing glasses that are too dark will put your eyes in a dark room environment. People's eyes will automatically expand their pupils in a dark environment. Long-term pupil expansion can easily lead to glaucoma and other diseases.

　　Therefore, dark gray is generally the best choice for sunglasses, followed by dark brown and black, and blue and purple are the worst, because these two lenses will transmit more ultraviolet rays. Try not to use yellow, orange and light red ones.

　　3. The lenses of sunglasses should be smooth and without scratches.

　　When selecting lenses, pay attention to the surface of the lens. It should be smooth, without wear marks or bubbles. Lay the lens flat and look at it from the horizontal direction. There should be no warping of the lens. You can hold the sunglasses 45 cm away from your eyes, observe the surrounding vertical and horizontal lines through the glasses, such as window frames or door frames, and then move the glasses up, down, and back. If the straight line is found to be distorted or oscillated, it means that the lens is deformed and should not be purchased. Lenses that are uneven or have marks or bubbles may cause discomfort such as dizziness after wearing them, so you should not buy them.

　　4. How to prevent sunglasses syndrome

　　Sunglasses syndrome refers to long-term wearing of sunglasses, which causes vision loss and blurred vision. In severe cases, it may cause symptoms such as headache, dizziness, vertigo, and the inability to look for long periods of time. This disease is manifested by a variety of uncomfortable feelings. For example, in the early stage, there is obvious numbness and tingling in the area around the eyes and nose. The symptoms are more obvious when breathing, which looks very similar to cold , and some people feel like there are small bugs crawling away on their face, numbness in the upper jaw gums, discomfort in the upper incisors, and poor local blood circulation. skin Inflammation, eye soreness, and vision loss. These discomforts usually appear after 2-3 weeks of wearing sunglasses.

　　To prevent sunglasses syndrome, first of all, you must choose and use sunglasses correctly. Choose glasses with the distance between your pupils consistent with your face shape. In addition, try not to wear large sunglasses as much as possible. When you must wear them, shorten the wearing time. After taking off the glasses, use your fingers to massage along the eye sockets and both sides of the nose 10-20 times. Once sunglasses syndrome occurs, you should stop wearing sunglasses immediately.

　　Sunglasses lens classification

　　1. Anti-reflective protective lenses: This kind of lens is coated with a thin layer of magnesium fluoride on the surface to prevent strong light reflection, allowing you to see things more clearly without being disturbed by strong light. To test whether your glasses really have anti-reflective protective lenses, you can point your glasses at the light source. If you see purple or green reflections, it means that the lenses are indeed coated with anti-reflective protective film.

　　2 Colored lenses: Also known as "dyed lenses", some chemicals are added during the lens production process to make the lenses appear colored and absorb specific wavelengths of light. This is the most common lens type used in sunglasses.

　　3. Tinted lenses: This type of lens has the same effect as colored lenses, but is made in a different way. It applies color to the surface of the lens. The most well-known is "gradient tinted lenses". The color is the darkest on the top, and then gradually becomes lighter downwards. Generally, sunglasses with prescriptions mostly use tinted lenses.

　　4. Polarized lenses: In order to filter the dazzling rays of the sun shining in equal directions on water, land or snow, special vertical coatings are added to the lenses, which are called polarized lenses. It is most suitable for use in marine activities, skiing or fishing, but it is not suitable for daily life, especially when driving, because it will make you see more clearly.

　　5. Photochromic lenses: Some people call them "photosensitive lenses". Because silver halide chemicals are added to the lenses, the originally transparent and colorless lenses will turn into colored lenses for protection when exposed to strong light, so they are suitable for both indoor and outdoor use.

　　According to confirmation, the best lens colors for sunglasses are brown, gray and green. Let’s take a look at the protective effects of various colors!