Mirrored sunglasses.

Mirrored sunglasses

Today, manufacturers offer a huge selection of optical lenses with various protective coatings that can be multifunctional and multi-layered. So, sunglasses with mirror effect designed to eliminate glare - at sea or in the snowy mountains. Lens, more shaded in the upper part with a smooth transition from top to bottom (gradient lens), will be good when you need protection only from the upper bright sunlight. But this option may cause fatigue the eye, it is desirable to have a uniform darkening of the glasses. Sunglasses with polarized lenses successfully neutralize the blinding brilliance, increasing the contrast and sharpness of perception, reducing eye fatigue, so they are irreplaceable for drivers and fishermen.

Antireflection coating makes the lens as transparent as possible, thus reducing the load on the eye and removing eye strain when wearing sunglasses. Strengthening coatings protect plastic lenses from minor scratches, increasing the operation life of the glasses. Hydrophobic dirt- and water repellent coating quickly makes lens transparent after dewing.

Watch for traffic lights.

Not any sunglasses suit for driving. The minimum amount of light, passing through the lens in the daytime must be at least 8%, and its maximum of absorption, respectively, may not exceed 92%. Thereof isn't recommended to use a very dark glasses with lenses of category 4 while driving. The lenses of saturated colors - red, green or blue - can disrupt the perception of signal colors of vehicles control, even distort the traffic signal, and therefore also not suitable for drivers. At night, the most safely to use colorless lenses with antireflective and anti-blinding coatings. It is best protects the driver's eyes a glasses with traditional browns and grays, and yellow (honey, golden or pale lemon). The orange sunglasses have most pronounced anti-blinding effect.

Protection from ultraviolet radiation.

The blue-violet part of the light spectrum is most dangerous to the eyes, as it easily passes through the cornea and lens, and its excess is causing to damage of a retina. Children, the elderly, patients with eye disease who had undergone surgery on the retina or the cornea (eg, laser vision correction), and without exception, blue-eyed blonds and representatives of Caucasoid type to suffer from bright sun in the spring and especially summer. But for the other it is not safe. Craftiness of excessive exposure to solar radiation consist in that person does not see or feel its, but over time it making itself felt.

Statutory requirements for sunglasses are regulated by national standards. According to them, there are three main groups of sunglasses - cosmetics (Cosmetic), conventional (General) and the glasses high degree of protection (High UV-protection). Cosmetic lenses - pink, purple, green and blue - are ineffective to protect and serve only as an accessory. Lenses high degree of protection required for high mountains and polar regions, equatorial-tropical regions, and conditions of ozone anomalies. And finally, lenses General - this summer lenses that meet the requirements of Europe and North America. Sunglasses with high level of UV protection can be with lenses of neutral, brown, greenish-brown color, but not with blue and purple. When choosing sunglasses, pay attention to their labeling. "UVA" and "UVB" shows the percentage of protection from ultraviolet rays (type "B" is considered the most harmful, and type "C" absorbed by the atmosphere). The designation "UV-400 nm" means that the lenses protect eyes from all UV light with wavelengths below 400 nm (the average length of light waves, reaching up to our eyes, - 290-380 nm). If the figure is less than 400, then still part of the rays is passed. Information about protection against infrared radiation does not write on the sunglasses usually and, as a rule, it is implied by default. Some lenses do it better than others, such as lens with polarization.

  

FYI: Every day the National Weather Service calculates the predicted UV Index for the next day in each area of the U.S.

Everyone knows to wear a hat or sun block to protect against ultraviolet radiation. But most overlook the importance eyewear play in protecting their eyes against ultraviolet harm.