The sun blinds the eyes

When you live in a city of fog, such as London, or in a city of rains, such as St. Petersburg, it seems incredible that the sun, the very sun that we are so lacking, can be dangerous. Of course, everyone has seen the snow-capped Alps and other ski resorts and well imagine, if not in reality, then from video and photo materials, these very conquerors of mountain peaks or just skiers in sunglasses. Yes, even in what glasses! Black glasses, a frame adjacent to the face on all sides – yes, the sun blinds the eyes.

But when the sun appears daily, it is summer outside, you want warmth, light and tan. What snow blindness? Having finally waited for things to let us rest, we with our heads uncovered and unprotected eyes enjoy all that nature has given us in a fairly short period of summer and still try to snatch as much happiness as possible that has finally fallen to us. In a short time to get light, warmth, memories for the whole year, without the sun, human bioenergy falls, gets lost in an endless series of monotonous everyday life.

And then it turns out that the sun is no exception to the general rule: there are no absolutely good or absolutely bad phenomena in the world around us. It is good to live in harmony with nature and with the sun as well. For example, on August 1, 2008, dozens of Russians damaged the retina of the eye during a solar eclipse. They complained of a sharp decrease in vision and a spot in front of their eyes. Photokeratitis is a burn of the cornea of the eye, which can appear both as a result of direct solar irradiation and as a result of irradiation with artificial sources of ultraviolet radiation. Also, exposure to light on insufficiently protected eyes can lead to clouding of the lens (cataracts).

It is believed that solar energy is 19% scattered in the atmosphere, 34% return to outer space, only 47% get to earth. Not all sunlight has the same effect on the eyes.
The risk is primarily UVA ultraviolet rays with a wavelength of 320–400 nm (the so-called black light), since they pass best through the atmosphere, and to a lesser extent UVB-band, whose wavelength is 280–320 nm, and UVC rays (100–280 nm) are almost completely absorbed by ozone, water vapor, oxygen and carbon dioxide.
The total amount of ultraviolet rays reaching the Earth's surface depends on the following factors:
• on the concentration of atmospheric ozone above the earth's surface (unfortunately, its amount decreases, leading, among other things, to an increase in the negative load on human eyes of ultraviolet light)
• on the elevation of the Sun (at equatorial latitudes and, when the sun is at its zenith, the effect of UV radiation is stronger)
• from the height above sea level (with an increase in altitude above sea level for every 1000 meters, the level of ultraviolet radiation increases by 10% – 12%)
• from atmospheric scattering
• from the state of the cloud cover (with a clear sky, the radiation is higher, but the presence of clouds creates only the illusion of reliable protection, the radiation is scattered and reflected from various objects, absorbed only partially)
• the degree of reflection of UV rays from the surface (for example, pure snow reflects 80% of the rays, white, quartz sand of the beaches – 40%, in the water at a depth of 0.5 meters the level of UV radiation is 40% of the level of UV radiation on the surface)
• the shadow covers up to 50% of UV radiation

Based on these factors, they select ways to protect against the effects of ultraviolet radiation on the eyes. can not look at the sun, and even at a solar eclipse (although the sun seems to be closed), with unprotected eyes, and neither folk remedies, like sooty photographic film, nor ordinary sunglasses, which are designed to protect against scattered and reflected light, will help.
2.When buying sunglasses, pay attention to the marks that are either applied directly to the glasses (on the inside of the temples, in the form of a sticker on the glass), or are written in the passport. Glasses that give maximum UV protection will be marked "400 UV" or "100% UV".
3.  Glasses can be made of glass and plastic, glass is more expensive and more durable, and if the surface of the lenses has damage or roughness, then such glasses cannot be worn for a long time, because the eyes will adapt and correct interference.
4.  Glasses should cover not only the eyes, but also the space around them, otherwise the reflected and diffuse ultraviolet will fall on the retina, in addition, premature wrinkles form around the eyes.
5.    When choosing glasses, take into account the peculiarities of your lifestyle: for drivers, for example, glasses with a lighter lower part of the glass are better suited – it is convenient to look at the devices in them, the same glasses are good to read outside the room, in the mountains or at sea – the darkest possible glasses, preferably with a polaroid coating, which will block the access of glare from water, sand and snow. Many people like chameleon lenses, which change their color, becoming lighter indoors, and darker in the sun.
6.  Contact lenses, even with UV protection, cannot be considered good protection against radiation by themselves, if only because they do not protect the skin around the eyes. But they are better than glasses protect against scattered and reflected light. Thus, for ski resorts, recreation on sea sandy beaches, we can recommend a combination of contact lenses with constant protection against UV and sunglasses or shade.
7.   When selecting lenses with sun protection, it must be borne in mind that conventional lenses absorb approximately 10% of UVA radiation and 30% of UVB rays; lenses with a UV filter of the 2nd class – not less than 70 and 95%, with a UV filter of the 1st class – not less than 90 and 99%.
8.  In sunny weather, spend more time in the shade and remember that shadow is not a complete protection against ultraviolet radiation.
9.  Wear hats, visors and glasses.
10.    Keep in mind that the sea and mountains are places of increased danger for eyes uncovered from the sun.

Treat eye protection from the sun with great care. Explain to children that the sun is not only a source of life and light, but also a source of danger to the skin and eyes, and how to protect the eyes from the harmful effects of sunlight.
Before the vacation period, before spending most of the time in the sun, before conquering the light-reflecting peaks, look with your eyes closed to the sun at sunrise. Although your eyes are closed you will see the color orange and feel the warmth, your eyes will prepare for the sun's rays. Your mood, beauty and health will only benefit from solarization (the so-called procedure) even if the vacation is postponed.