How to choose sunglasses

In summer, many people can not do without sunglasses. But most of them do not know how to pick out glasses. Some people choose glasses by design, some by shape. And about other, very important criteria people just don't know. For example, the material and color of the lenses, the uniformity of their coloring. In this article You'll know about it.

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Why do we need sunglasses?

Nature has endowed man with good protection from UV rays. Once they were on the sun, the person involuntarily narrows his eyes, and the pupils of his eyes narrowed. Also, thanks to the lens of the eye and its natural filter the harmful sun rays do not reach the retina. Squinting, we contribute to the appearance of wrinkles around the eyes. Hence, in glasses we don't squint and wrinkles appear later. But very few points completely block ultraviolet rays, therefore, the choice points should be taken seriously. And otherwise protect and to harm yourself using such glasses, it is easy.

Glass blocks UV, so glass sunglasses are harmless. But here's the problem – they are quite heavy and so wearing them is not very convenient. To alleviate glasses, glass glasses replaced with plastic. But plastic with UV "cannot cope". And, most importantly, the pupil in such sunglasses is not narrowed due to the obscuration created by the glasses. In these conditions, increases the load on the eyes. All of this subsequently can weaken eyesight, cause clouding of the lens.

To buy sunglasses have to expensive salons, because only there can be "correct" points. But most of all, wherever you bought, everywhere you will hear: "These points do not pass ultraviolet rays".

A little about color lenses

Different colors influence people in different ways. For example, a yellow color, according to Goethe, "pleasing to the eye, expands the heart, invigorates the spirit, and we feel warm." Indeed, some people experience an emotional lift when you see the world in shades of yellow. Blue color, on the contrary, peculium. Green is considered to be unnatural, because the sky is never green. Red does look terrible, frightening.

Some scholars have tried to classify colors according to their effect on humans. For example, Vaughan Cornish divided the colors into "warm" is red, orange, yellow and yellow-green and cold — blue-green, blue and purple.

When thinking about the color points from a practical point of view – colored lenses harmful to health. For example, spectrum blue glasses damaged lens substance. Wearing red glasses, you can effortlessly disorientates in space.

Following the advice of eye doctors, need to wear glasses really block the ultraviolet rays and weakening the blue color spectrum. Now it is not known how different colors affect humans, but it is believed that the selection of any one among a spectrum of other causes of inattention and fatigue. This is especially important for drivers, as some colors may absorb others. For example, you can mix up the colors of a traffic light: green is absorbed red glasses, red green. Dark glasses can is banal not to see the road even on a Sunny morning.

Ultraviolet rays are divided into two types: middle (A) and far (B). More harmful rays are considered to be B, but from the rays And of little use. If the label points you will see: "Blocks at least 90% UVB and 50% UVA," which means that the glasses little miss B rays and only half block the rays of A.

Also an important criterion in the selection of points is the wavelength that they block. Maximum value is 400 nanometers. If the label you see this value, you bought a good points, and they will protect your eyes from UV rays. But very often points not as good as the manufacturer describes them.

What do you do to find out how effective your glasses? You can determine what your points of quality, if after extended wear under the eyes are tan. Also lenses must filter out some portion of the visible light spectrum. In simple terms, they should be quite dark, and have a grayish color. The color should be uniform and not only at the top, otherwise it will lead to eye strain. I do not need to repeat that the worst choice would be sunglasses with blue lenses.

Also, never been proven better than a glass glasses plastic. The main advantages of glass lenses can be attributed to their absolute protection from ultraviolet rays (for example, not even tinted quartz glass fully absorbs UV). They are harder to scratch than plastic. The main downside is the inconvenience when carrying, the weight. Wearing these glasses is directly associated with risk for the eyes – the shards fly in your eyes if these glasses are broken. In some European countries imposed bans on glass lenses.

With regard to plastic points, now they add some additives to reduce brittleness of glasses and absorbing ultraviolet light. Alas, anywhere except in the laboratory, customers will not be able to know whether supplements actually.

Usually, buying points somewhere on the market, you will see there is a label in the Russian language. It is more usual in English. Therefore, you should remember a few English words: "plastic" – plastic, glass – glass (not to be confused with "glasses" glasses) and the abbreviation "UV" – ultra violet rays. Otherwise, the choice of plastic glasses are lighter than glass choice: all of them are lightweight and unbreakable.

The main criterion by which selected sunglasses is the quality and appearance. That's why I advise You right now to look at the page http://fashiontrends.com.ua/solncezaschitnye-ochki (http://fashiontrends.com.ua/solncezaschitnye-ochki). Here You will be able to pick out great glasses from top brands, quality products which is the reference on the market today!</p>