Correct selection of sunglasses

Good sunglasses will not change the true nature of the object
Polarized lenses generally use the same lightweight precision and contact lenses made of synthetic resin, synthetic sheets by the seven outermost layers is wear layer; second, six are shatter-resistant reinforcing layer; Third, five is the UV filter layer, the middle layer is the most polarizing filter layer. Polarized lenses can effectively filter out harmful ultraviolet light reflection and have shatterproof, wear and other functions, is the most popular discount oakley sunglasses.
Good sunglasses, depending on the material deformation, not fuzzy, the overall feeling is transparent. You can find a card, look at the past through the lens, the color pattern on the card is still the inherent color, not because it is the blue lens and blue, or purple glasses and purple, is the general good glasses.
Some poor glasses, human pupil and the optical center of the lens cannot be coincidence, so some people wear sunglasses but can not see things later on, there are some uneven dyeing or not polished lenses and other issues, which may lead to vision does not clear, eye fatigue, wear a long time if it will lead to decreased vision, causing chronic injury to the eyes.
Sunglasses are not darker the more eye
Scorching sun, sunglasses are essential for people to travel one shade sunscreen, a lot of people think that the darker the lens the more it can prevent ultraviolet damage to the eyes. Xinqiao Hospital, Third Military Medical University, experts say, sunglasses are not the darker the better, the lens color too but may cause damage to the eyes.
Whether it can prevent UV rays and lens color depth does not matter, but by the lens uv (ultraviolet) criteria determine, for example, uv400 lenses can prevent 100% UV, uv100 lenses can prevent 96-98% of UV rays.
Therefore, the choice depends on the lens oakley sunglasses cheap uv standards, rather than look at the color shades. Even if it can prevent ultraviolet radiation, but also should not choose too dark sunglasses, lens color too deep will seriously affect visibility, easy on the eyes to see things difficult because of the damage. Sunglass lenses should be guaranteed to pass through 30% of light, gray or green for the best.
Identify the extent of the recipe fly sunglasses
To pick a fly sunglasses, remember the simplicity of a few tricks can help you quickly determine.
First, look at the lens. Lenses if there are scratches, impurities, bubbles, do not buy. Holding sunglasses against the fluorescent light to see if the specular reflection of the fluorescent shadow is wavy or water patterns, the proof lens is not flat, after wearing the lenses for vision damage.
Two to see signs. Regular UV sunglasses packaging must be marked in accordance with national standards UV protection level (uv), labeled with uva (filter wavelength 320-420 nm), uvb (filter wavelength 275-320 nm) and uv400 (filter wavelength of 400 nm or less ) three kinds, these three have UV protection. Usually sunglasses uv index of 96% -98%, and in general, 100% uv index is unlikely.
Three Views "degree." Ordinary sunglasses are plain mirror, not only with optical lenses of the "degree." Generally more than 15% if the diopter, you pick up the wear walk around, there will be a feeling of dizziness. Optician generally can test glasses "degree" of the instrument, the sunglasses get past a test, you can know your sunglasses "degree" There is not exceeded.
Car is recommended to choose brown and gray lenses
The deeper the color of sunglasses is not better, the color is too light filter effect is too small; affected the color is too deep sense of color vision has also weakened. Simple self-test method is to wear sunglasses mirror, dimly visible to the limits of its own pupil. .
But if you are wearing sunglasses while driving is more, it is recommended that sunglasses color can not be too deep, it is best to choose brown, gray polarized lenses. Tinted lenses to filter out a lot of blue light, can improve the visual contrast and clarity, suitable for heavy air pollution days, or when driving in the rain and fog city wear. The gray lenses cheap oakleys sunglasses can absorb any chromatography balanced, put on after seeing something instead of a clear color will darken.