Identify sunglasses have UV feature

Scorching sun, the streets more and more women wearing discount oakley sunglasses in the summer for their own charming style, while adding, sunglasses can also play intense sunlight to prevent eye irritation effect.
Many women simply choose sunglasses style, while ignoring the color, lenses, UV index and internal factors, not only would not achieve its proper role sunglasses, heavy then also produce dizziness, eye soreness and other symptoms not suited to, and sometimes will produce unresponsive, color vision illusion, depending on the material inequality walking symptoms, and may even cause accidents, it seems, cannot buy sunglasses really sloppy.
UV Index: UV filter
Eyes 6-8 hours after receiving ultraviolet light, while his eyes stinging and foreign body produces more severe pain, photophobia, tearing, eye spasm, conjunctiva hyperemia, eye sunburn are the performance, there will be severe corneal large epithelial exfoliation, vision loss and other symptoms.
Sunglasses and was able to block UV rays, because the lenses add a layer of special coating, the blocking, UV absorbing, but also blocking a portion of visible light transmittance of the lens decreased. Therefore, high-quality sunglasses block UV ability, transmittance decreased and small, and the coating has certain hardness easy to wear.
Identify whether there is a UV sunglasses feature some products can be seen on the label or lenses such as "UV", "uv400" etc. clearly marked. "UV index" that is UV filtering effect, which is a very important purchase criterion sunglasses. 286nm-400nm wavelength of ultraviolet light is known, in general, UV index of 100% is not possible, most sunglasses UV index of between 96% -98%.
tips: labeled as "uv400" sunglasses can reach more than 90% of UV defense level, the lens has been specially processed, can block ultraviolet wavelength less than 400nm. You can choose to wear contact lenses contact lenses with anti-ultraviolet function, can filter out 90% of ultraviolet rays, and then wear cheap oakleys sunglasses, even higher level of security.
Color: medium depth is better
Lens color should be the color of the surrounding environment is not distorted. Not wearing sunglasses before, the first observation of red, green, yellow and other colors of objects, and then put on sunglasses, observe the same object twice the observed color cannot be cast, otherwise it will reduce the ability to identify the traffic lights. According to experts, different colors of lenses have different functions, generally medium depth, gray, brown, and green better. Also, the lens color selection should be based on visual color distortion, objects, sharp edges, can effectively identify different colors of lights as a principle.
TIPS：
Brown --- absorb ultraviolet and infrared capabilities best to make eye fatigue.
Gray --- can be completely absorbed infrared, and most of the ultraviolet rays, and will not change the color of the original scene.
Green --- absorb ultraviolet and infrared features are good, but sometimes the color of the scene through the green lens is changed.
Light color --- bike or car cannot choose the lens color is too light, because wearing a light color of the lens, will reduce the contrast of the immediate scene, and cannot effectively identify the signal.
--- Choose amber lens movement, which can effectively increase the contrast and absorb blue light, increased exercise in comfort.
Lens: Check diopter
People rely on regulation in the sun often pupil size to adjust the flux, when the light intensity exceeds the ability to regulate the human eye, it will cause harm to the human eye. Sunglasses can play a role in blocking the sun to reduce eye fatigue or damage caused by the light stimulation. While wearing bad glasses, his eyes as if seen in the dark matter, the pupil becomes large, but will be a lot of residual ultraviolet injection in the eye, the eyes hurt.
In addition, the lens surface is not smooth rule, see external objects will produce distortion distorted, so that the eye soreness, followed by nausea, loss of appetite, forgetfulness, insomnia and other symptoms of visual fatigue. In addition, on a cloudy day and did not need to wear sunglasses indoors, regardless of when wearing indiscriminate chaos, will increase the burden on the eyes adjust, causing muscle tension and fatigue, vision loss, dizziness and severe, cannot be long as the other symptoms.
Tips: regular sunglasses are plain mirror series, in accordance with national standards, plain mirror diopter tolerance is ± 0.08d, and do not affect vision optical flaws. Diopter once exceeded, will cause eye fatigue, eye injury and even "culture" into the eyes of patients with myopia or hyperopia. To identify strengths and weaknesses have a simple lens quality identification methods: oakley sunglasses cheap placed in front of swaying back and forth to see whether the object lens with the move. If you move together, indicating a diopter lenses and may cause eye disadvantage. And the lens surface should be smooth, ripple-free, flawless, no bubbles, no wear marks.