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Vacations in the snow: for enthusiasts they are beyond compare. And if the sun is shining, so much the better, but descents are a challenge even when it is gray and cloudy and people are not always aware that it isn’t just legs and ankles that are exposed to considerable risks, the eyes also need maximum protection.
Even in the depth of winter and on dull days, the sun’s rays can still damage the eyes. It should be remembered that ultraviolet (UV) light is always around, that 80% of the rays passes through clouds and that reflective surfaces can make the situation worse.
A grassy or watery surface reflects less than 10% of the sun’s rays, but a snow-covered surface can reflect at least 80%. The intensity of UV rays also increases with altitude, because the reduction in absorption factors is inversely proportional. It is estimated that the intensity of the sun’s rays increases by between 6% and 8% every 1,000 meters, and even reaches 12% every 1,000 meters at very high altitudes.
More UV rays are reaching the earth nowadays because of the reduction in the ozone layer. As well as damaging the skin, excessive exposure to UV rays damages the crystalline lens in the eye (the natural lens that focuses images), reduces transparency and leads to damage that could worsen with age.
The consequences in the short term could be conjunctivitis, snow blindness, burning of the cornea, excess lacrimation, reddening or photosensitivity, but in the long term there could be more serious problems with the retina and the crystalline lens. This is why eye specialists have been saying for some time that it is essential to be protected from UV rays by wearing vision glasses (ophthalmic lenses) and sun filters (sunglasses) which have screens or protective photochromic lenses.
“Excessively bright light can cause glare, eye strain and irritation. UV rays can actually “burn” the delicate cells on the surface of the eye (the corneal epithelium) and cause smarting, twinges, the sensation of having something in your eye and, in the worst cases, intense pain. “Dermatologists confirmed many years ago that the sun is the most powerful natural ‘laser’”, explained Matteo Piovella, the Secretary of Italy’s Ophthalmology Association (SOI). “That is why, at all times, it is important to wear protective lenses and sun filters that also cover the area around the eyes to prevent rays from entering at the sides or from above, which would partially affect their efficiency”.
The most advanced technology now offers effective protection, such as photochromic lenses. These (such as ) are vision lenses for daily use. Totally clear and transparent indoors, Transitions? darken automatically outdoors depending on light intensity, and they block 100% of the UV rays to protect the eyes from reflections and to ensure vision wellbeing throughout the day. |
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发表于 2016-9-22 19:11:12