Jul 132014
 
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sunglasses

sunglasses

People often ask a question-how to make the right choice of sunglasses?

Where should you buy your sunglasses? We’ll try to answer these questions today. Besides as a fashion accessory, when choosing your sunglasses, is good to know their protective functions.At first place is the percentage of UVA and UVB radiations and the wavelengths blocked by the glasses.This sign should be on the label of all high quality sunglasses. There is one more indicator – coefficient of refraction: 1.4; 1.5; 1, 6 etc. The larger it is, the better the lens is.The sunglasses are made of different materials.Some are stronger, others are lighter. The most commonly used materials are the following:

Polycarbonate – durable and lightweight material
CR-39 – also lightweight material commonly used in the   manufacture of eyeglasses
Glass – durable, but much heavier than the above two materials

Absorption of light depends on the color of the glass.Gray colour glass diminishes brightness of the light and doesn’t affect on the perception of other colors. The brown colour reduces unwanted glare, and the same do those of the blue spectrum of the sunlight, but it changes the perception of the other colours and create a sense of depth. They are best suited for cross-eyed people.The green colour filters the blue light and reduces unwanted glare, reduces intraocular pressure, too.It gives a good contrast of the image.Yellow lenses are recommended for drivers during heavy fog or night driving.

Polarized lenses for sunglasses help reducing the sunlight when it’s reflected in water or other smooth and mirrored surfaces.Photo chromic lenses are those that become dark when exposed to UV rays.Depending on the intensity of the light, the lenses colour changes its intensity, too. Anti-reflective glass collects unwanted glare and reflections of light in your glasses, facilitating and protecting your eyes this way.

There’s no difference for the refraction of light between glass and plastic filters.

Experts say the proposed on the streets sunglasses are imitations and these glasses do not protect your eyes from harmful sunrays, worse they even may further impair your eyesight.Because these sunglasses actually don’t provide any protection against UV light, their lenses are made of non-optical polymer, used in the manufacture of plastic bottles, too.

When you make your choice of sunglasses, do not look at them only as a fashion accessory, but think about your health.Buy them from the optics or the store that will ensure the necessary quality of the glasses.Read carefully the label, which is obligatory for all sunglasses and get to know the protective features of the lenses before you buy them.

photo: http://uncrate.com/

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