Sunglasses – GearGuide

68431As far as UV protection is concerned, it does not matter if you wear sunglasses or goggles. In the summer the sunglasses are a must. Not only because it looks good, but also because it protects your eyes from the bright light. In mountain environments where the air is thinner and you are physically just closer to the sun, you cannot go without. However, many people do not realize that the harmful UV radiation in winter is much more dangerous than in the summer.

Image: Adidas Evil Eye Explorer Aluminium Zonnebril

In summer, the green environment reflects only about 6% of the light. In snow, however, this percentage is almost 95%. Only high-quality glasses of sunglasses provide eye protection against ocular lesion or eye inflammation and serious damage. This is because the sunlight, which contains a lot of UV radiation, can damage the retina. Even when the sun is not out, on cloudy days, the intensity of light on a snowy mountain is something you really need to arm yourself against.

Subjects:

  • UV-radiation
  • Category lenses
  • Colour lenses
  • Fit & how to choose

UV-radiation

Eye damage due to excessive light comes mainly from UV radiation in the sunlight (UV is an abbreviation of “ultraviolet”). UV radiation can cause corneal inflammation (snow blindness) and, in the long run, cataracts. Standard glasses and sunglasses resist UV to a different extent.

uv-stralingAbout 48 percent of the light is visible. The 52 percent that is not visible is subdivided into infrared light (45 percent) and ultraviolet light (7 percent). This latter category consists of UV-A, UV-B and UV-C rays. UV-A radiation is not harmful to your eyes. Too much UV-B radiation is.

The higher your are in the mountains, the more harmful the UV-B radiation. UV-C radiation is most harmful, but these rays are stopped by the atmosphere. Sunglasses with CE marking protect the eyes for one hundred percent against all UV radiation.

Snow blindness

Going without protection in bright sunlight, for example, during winter sports can cause an eye infection (snow blindness). The eyes then feel painful and are hypersensitive to light. Normally, this will pass over a period 24 hours (if the eyes are not exposed to more bright sunlight).

Protection

Eye protection is just as important as protecting the skin against the sun. An extreme exposure to UV rays can burn the eyes. This leads to faster aging of the most sensitive part of the retina (the macula), which may result in cataract. A good set of sunglasses is therefore not an unnecessary luxury. In order to choose the right glasses for different circumstances, it is useful to know more about different types of lenses and their properties.

UV radiation and glasses

Dark glass are not needed per se to stop the harmful UV radiation. A UV filter can be perfectly clear. The eyes themselves have a UV filter that protects the retina to a certain degree (but not the cornea, on the surface of the eye).

A darker sunglass is therefore not a guarantee that it is safer for the eyes than a lighter shade.

Ordinary transparent eyeglass glasses could have a UV filter that provides adequate protection, although generally that is not the case. Glass holds back a part of the UV so that in your car, for example, the windows already have a certain amount of protection. Lenses of mineral glass, however, are generally not thick enough to block UV radiation sufficiently.

UV 400

If on your sunglasses it is mentioned that there is “UV 400” protection, it will provide enough UV is retained to keep you safe in the sun.

This standard means that more than 99.5% of the radiation between 280 nm and 400 nm (UV-A and UV-B) is blocked, measured according to AS / NZS 1067: 200

Category lenses

Adidas-EvilEyeProLReplacementLenses-17066Lenses are available in different categories, each able to black a different amount of light. Lenses for sunglasses and ski-goggles resist light to different degrees. The darkness of the lenses is indicated by a category, from 0 to 5, in which the sunglasses fall.

 

         

 Cat  Amount of light through Light indication
 0 80 – 100%Esthetic, more contrast
 1 43 – 80%Soft/Damped sunlight
 2 18 – 43% Average sunlight
 3 8 – 18% Bright sunlight
 4 3 – 8% Extremely bright sunlight

 

Category 0

Light absorption 00-20% – This transparent lens filters virtually no light and is suitable for protection against frostbite, insect or wind.

Category 1

Light absorption 20-57% – This is a contrast-enhancing lens. For use in cloudy weather, dusk or fog.

Category 2

Light absorption 57-82% – Similar to Category 1, a contrast-enhancing lens. The difference is that this lens filters more light and thus is somewhat quieter for the eye.

Category 3

Light absorption 82-92% – This is the most widely used lens category because it offers the most possibilities. The lens filters enough light in bright sun and is therefore suitable for motorists, skiers, hikers, climbers, and cyclists.

Category 4

Light absorption 92-97% – These lenses absorb the most light and are the closest to the eye. Extremely suitable for use in high mountains and on glaciers. A disadvantage of high light absorption is that the depth display is a lot less than in a category 3 lens. For winter sports a category 4 lens is therefore not very suitable.

 

Comfort

The above-mentioned categories are mainly for the amount of comfort that sunglasses give against the glare of the sun. They are therefore not for actual protection because the eyes can only be damaged by UV radiation from sunlight. And, as we mentioned, a UV filter can be completely clear.

Colour lenses

Sunglasses are available with lenses of various colors. The effects of those colors on how you see the world are of course different. There are colors that mainly have a functional reason and colors that are more aesthetically intended.

Important when choosing the color lens is where and how to use the glasses. Do not just choose a color that makes the world beautiful, but go out of the moment of use. Yellow or orange glasses are contrast enhancing, which gives more depth; ideal for use in snow on cloudy days or during mountain biking in a dark forest.

In the bright sun you can wear brown or green glasses, and for everyday use, gray is most suitable, because of the natural vision.

Functional lens colours

Grey

Gray glasses, above colored, have the advantage of giving little or no color change. Because of less light in less light, colors become less intense. That goes for all sunglasses.

Grey-green

These make the most of the colors that the human eye is most sensitive to. As a result, you can see quite clearly, while still retaining a lot of light. Colors remain more natural, though on the cool side.

Brown

Brown glasses mainly filter out the blue of the sky. That blue light can reflect on snow and wet surfaces, which makes the image quieter with brown glasses, with improved contrast.

The world as you normally see it looks a lot lik lighting with incandescent lamps, colors and feelings are a little warmer. The colors you see are no longer really natural.

Because you feel more awake from blue light, you can feel less alert with sunglasses with brown glasses. Blue light also plays a role in overcoming jet lag, so it would be less effective if you wear a sunglass with brown glasses.

Yellow/orange

These are not really meant for bright sunlight, because the glass leaves quite a lot of light. They are more meant to have a better contrast, by filtering out the blue of heaven. They are mainly used by people who are important for sports, such as sports and winter sports. They also give a better view of mist or fog.

Degree of protection against bright light

The color of the lenses says nothing about the amount of protection they offer against harmful effects of bright sunlight. As long as you do not look directly in the sun, only UV radiation is harmful. An UV filter can be quite clear, so darkness or color of a sunglass, in itself, says nothing.

Sunglasses are not meant to use to look in bright light of lights or the sun. Wrong light can cause permanent damage to the retina. Blue light is the most harmful, so if you want to use sunglasses for this purpose, one with brown glasses is safest.

Polarizing lenses

Polarizing lenses also contain a polarization filter in addition to a UV filter. This filter has the characteristic of retaining the glare of the sun on road, water or snowflakes. How this works? Sunlight reaches the earth in wave movements. The light is radiating all sides. When it touches the earth, the light is reflected in two directions, horizontally and vertically. Vertical light allows viewing contrasts and colors, while creating horizontal light shine and glare. Water and other non-metallic surfaces backlight sunlight mainly horizontally and cause such a concentrated beam of sparkling.

The function of a polarization filter is to block horizontal light. With polarizing sunglasses, you have significantly less trouble with the nuisance of water, sunshine on the road and glare in many other situations.

Fotochrome lenses

Fotochrome lenses color darker as more light comes on. Crystals in the lens respond to the amount of UV rays. The more ultraviolet light, the darker the lenses color. Removing the UV radiation, the lenses are lighter. For example, Fotochrome lenses are functional during mountain biking. For example, the eyes are not blinded by the sun as you cycle out the forest. The glasses work less well in the car, because the tinted windscreen already prevents some of the UV radiation.

Lens material

Sunglasses lenses are made of plastic or glass. Plastic is strongest, can be easily coated with (mirror) coatings, is relatively scratch resistant and very light; ideal for active carriers. Well-cured glass lenses are generally more durable and scratch resistant, but also more expensive, heavier and more vulnerable.

Coatings

If you want to use one pair of glasses in different weather conditions, choose lenses with a coating or mirror coating. This makes the product a little more expensive, but has the advantage that the glasses get a much wider range of use. A category 2 glasses with orange glasses, for example, works contrast-enhancing on a cloudy day and also protects the eyes when the sun breaks through a mirror coating.

Removable lenses

Some brands have models in their assortment where standard different lenses are supplied. You can also order additional lenses for many models, which allows the glasses to be used in more weather conditions.

Fit

Quite important in choosing the right sunglasses choice is finding the best fit. A well-connected pair of sunglasses leaves a minimum of light along the edges, essential for proper eye protection. Tryin models on, is the only way to find out which model is best on your face.

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