Mountaineering necessary: the sun glasses

High mountain snow is easy to damage the eyes, in terms of ultraviolet ray, height of 10000 feet of snow reflected light than the more than 50% of the sea, open hole networks bun and is easy to damage, causing great pain called snow blindness, sunglasses can reduce the damage, but don't be cloudy weather, because ultraviolet light can penetrate clouds, dazzling light will cause headache, sunglasses will have 95% - 100% of the filtering effect. Travel for ice with sunglasses transmittance (requires five to ten transmissionrate) And multi-purpose sunglasses have 20 penetration rate. When buying in a mirror, if you can easily see your eyes are too bright, the color of the lens is grey or green - if you want to see the real color, if you want to want to see the cloudy or foggy weather good carefully choose the yellow lenses, for infrared, unless you face the sun will be direct damage, but generally sunglasses can prevent the infrared radiation and protect your eyes, the sun glasses have side protection device to reduce through the eyes, but must have good ventilation to prevent the lens fog, or use of anti fog lens or fog resistance of the cleaner, you need to take a pair of spare copies of the sun glasses to avoid loss may also use cardboard or cut into fine strips cover to the eyes. Most climbers would rather use contact lenses, because glasses can slide along the bridge of the nose, can improve visual acuity, there will be no water spots, but there are still shortcomings such as the sun is too big, the wind sand, dirt can cause eye irritation, at the same time outside not easy cleaning and maintenance.