Not on all trips, sunglasses are a necessary piece of equipment. But in many cases, moving around on a sunny day with comfortable glasses is much more comfortable than without them. At the same time, many novice tourists have heard true and not very stories about the terrible consequences for those who are without glasses in the mountains. The truth is that
– In addition, glasses also perform the function of mechanical protection of the eyes from dust, pebbles, insects, small particles – the intensity of solar radiation increases, including ultraviolet radiation, which is especially harmful to humans, and some surfaces reflect much more UV than others. Ultraviolet reflects snow, ice (up to 80%), light sand (up to 35%), water (20%) especially well. But even simple soil (earth) can reflect up to 15% of solar radiation. We conclude: in high altitude conditions (above 3000m) goggles are needed even if there is no continuous snow-ice cover. In conditions of continuous snow-ice cover, goggles are needed in any case. They are also needed when hiking in deserts, steppes, plateaus, and on water trips and expeditions.
What is ultraviolet? This is part of the emission spectrum of our luminary with a wavelength of 180 to 380 nm. International designation UV. There are three types of ultraviolet radiation: UVA 315-380nm, UVB 280-315 and, the most dangerous for living organisms, UVC 180-280nm. What is his danger? In significant doses, ultraviolet not only contributes to tanning, but also destructively affects living organisms. The consequences of excess exposure for humans are sunburns, retinal dysfunctions, partial loss of vision (for climbers and polar explorers this is the infamous “snow blindness”).
To save your eyes is possible only using high-quality optics, which fully protects against ultraviolet radiation and excessive light load. Do not confuse these things with each other! Many people think that the darker the glasses, the better they protect against UV radiation. This is a blunder! Completely light glasses of glasses can completely protect against ultraviolet radiation, while at the same time, very dark glasses of an incomprehensible manufacturer can leave you only with the illusion of protection and cause great harm. The natural reaction of a person to the bright sun is squinting eyes, which reduce radiation exposure. If you wear sunglasses without protection, then you will suffer much faster from ultraviolet radiation.