Snow blindness. How dangerous bright snow?

Winter. The long-awaited vacation. The festive mood. Ski Resort. Tatras. Picturesque view from the confluence of the winter and summer - snow-capped mountains and bright, it would seem, the warm sun. Everything in the New Year's glittering, inviting to plunge into this unforgettable atmosphere with his head.

Suffering from the anticipation, you are trying to quickly leave the gloomy and dark room of his hotel, seeking fresh air, under the caressing rays of the standing high in the zenith of the sun. Quickly pulling a ski suit, clutching skis, you finally runs out, with a joyfully rushing to the nearest ski-run. You are eagerly looking at the neighborhood, enjoying the bizarre landscape, from excess of emotion in your eyes welling tears that you immediately smacks dressed in a hand glove. And then you have to climb a mountain, now standing at the top, considering the fascination opened for many kilometers landscape.

But suddenly there is some discomfort in the eyes, different levels of the surface becomes hard to distinguish. Appears feel as if the eye has got many small grains of sand. Wondering where the snow took the sand, you will often blink, hoping to wash his current eyes with tears, and the feeling of sand are added, and colic, which every moment is becoming stronger.

You return to the infirmary of his hotel to find that the holiday spoiled by a few days. Because it over time, discomfort and inflammation rezyam align the eyes and swelling of the eyelids, a man truly blind. There is a snow-blindness.

And sometimes more so. Taught by "experienced colleagues, mindful of the dangers of bright snow, you boldly wear-tested many times on warm Sunny" glasses. And go to the mountains, safely looking at the surrounding landscape. Only through time yet again the discomfort, the feeling of sand in the eyes, and then it hurt. Do I have to say that after a few hours as there is snow blindness? Why is this happening?

Let's first be dismantled, what this phenomenon is. Why does it actually is called "Snow" blindness? And why it does not arise in our home when we almost for days admiring the snow fell, but it may be just a couple of minutes spent in the sun and the snowy mountains?

In these mountains, especially in early spring and spring period, solar activity is greatest. At an altitude of 3000 meters and a fairly thin layer of the atmosphere, passing many coming from the sun UV rays. Snow, as we know, very well reflects the light falling on it. Remember snowy night in your city. At this time of year at night on the street is much lighter than in summer, is not it? Snow reflects moonlight, further illuminating everything around. The same happens in the winter sun in the mountains, only to have affected up to 40% of sunlight, including ultraviolet radiation. This phenomenon is more typical of the southern mountain regions, but in the spring may occur in the north.

The result reflected rays fall into the curious eyes wide open, causing a burn the retina. As evident discomfort at first, but after several hours of the development of photophobia, or even total blindness (snow ophthalmia). There have been reports of a weak form of blindness under the action of sunlight reflected from the water surface.

It should be noted that in these mountains have to be vigilant and on cloudy days when the sun does not seem to be particularly bright. It is believed that in such times the risk of snow blindness, even higher than on sunny days. The fact is that on a cloudy day because of the scattered light all around is the same white: the sky and snow and ice. Hills, and snowy slopes, even large, do not cast shadows and become indistinguishable. Anxiously watching the road, have to strain your eyes to the limit. Thus, the pupils dilate, and the eye is deprived of natural protective mechanism, which in bright light is restricted from entering into it reflected sunlight. There is a burn of the retina, there is a snow-blindness.

Victim of this disease may become even experienced skiers, as well as blindness does not develop immediately, but within 4-5 hours after exposure to light (although the impact may be a few minutes). The result may be such a picture - go for the snow, his eyes a little bit blind, but it was tolerated, and in the evening there were problems ...

How manifest this disease? Is it dangerous? As mentioned above, snow blindness (snow ophthalmia) first appears uncomfortable in his eyes, a feeling of falling sand, watery eyes. Over time, there is pain in the eyes, redness of the mucous, edema. Developed photophobia - intolerance of bright first, and then any, even relatively weak light. After 4-5 hours can develop a complete loss of vision.

What to do if disaster overtook you or your friends? First of all, no need to panic. It should be noted that this phenomenon is reversible, and a few days later, as a rule, the sight is fully restored without any impact. The victim needs to close his eyes from the light (wear a mask or blindfold) and transmit it in a dark room, where first aid and also call a doctor.

What has not previously been treated only Craftsmen snow blindness! Compress, alcohol tincture of opium, even snuff tobacco! As first aid for snow blindness recommends that you rinse the eyes with a weak solution of boric acid (Boric acid, acidum boricum), soda, pale-pink solution of potassium permanganate (permanganic acid) or strong cold tea. Then the eye bandage is put on dark or dark glasses. Occasionally the eye to reduce pain put cold lotion.

Specialists for the treatment of snow ophthalmia disinfectants, sulfanilamidnye drugs. But the main thing - to isolate the eyes from sunlight. Victim to ensure peace, put it in a darkened room. Often, when the impossibility of applying medication, wearing a dark bands - a unique measure for this disease. Typically, 1-2 days the symptoms have subsided, but after 4-5 days the disease completely passes. As mentioned above, usually vision is fully restored. Often, however, remains a heightened sensitivity to bright light.

As you see, disease rather unpleasant, does not last one day, so it can be fun to spoil your entire vacation. Therefore, gathering in those sunny mountains, should not forget how to prevent snow blindness. Who warned, he is armed, is not it?

Thus, the arm will wear glasses. And, not our beloved "colored" sunglasses, carrying with them memories of spending a pleasant few days in the warm sea resorts. Because many of these glasses protect from light, but do not protect against ultraviolet radiation, which easily penetrates through the glass. Cheap plastic glasses can even cause retinal burns - in fact in the dark pupil expands. As a result of penetrating ultraviolet freely falls on the retina, causing a burn. Therefore it is important that the certificate and glasses themselves were the CE mark, which guarantees the protection of the eyes from ultraviolet radiation.

If there are no points, or you lost them, or they are broken you just do not like, we can substitute from pieces of wood, cardboard, strips of dark fabric with a pinhole or a narrow slit for the eyes. You can also blackened with soot skin around the eyes, if you're not afraid to frighten a war paint around.

However, we must remember that glasses or their substitutes should be not only bright, but in cloudy weather, as well as in that in both cases there is a risk of snow blindness.

But what glass to use when choosing glasses-filters? The views of experts here disagree. Perhaps this is because, as far as the glass of any color allowed to work, travel, conduct surveillance. Ie much depends on individual preferences. Most researchers in the Arctic and Antarctic preference points smoky color. Dark glasses have a significant advantage: reducing the brightness of the lighting, they do not change the perception of surrounding objects.

Now, hopefully, going to the High Tatras mountains or other solar, you'll look like a real experienced skiers, owning a everything necessary for that pleasure, including the correctly matched points-filters.