CLIMB SKILLS
W
e all live for bluebird days in the mountains. But our eyes are very sensitive to light, and it’s essential to protect them from solar radiation and ultraviolet (UV) rays.
WHY PROTECTING YOUR EYES IS A GREAT IDEA!
Higher altitudes allow more solar radiation to pass through the atmosphere, subjecting our eyes to more potential damage. At 4,000m (similar to the Aiguille du Midi in the Mont Blanc massif) there is 2.5 times more solar radiation than at sea level, and even at 2,000m the radiation level is still 1.5 times higher.
Ultraviolet light can be very harmful. The sun emits three different types of UV radiation: UVA, UVB, and UVC. UVA rays (95 percent of radiation that reaches the earth’s surface) are moderately harmful and can cause light pigmentation of the skin. UVB, however, is extremely harmful (1,000 times more aggressive than UVA), causing snow blindness, skin cancer and most sunburns. This high-energy radiation still has an effect in cloudy weather, as clouds absorb no more than 10% of UV rays. UVC is the most damaging type of UV radiation, however it’s entirely filtered out by the atmosphere.
Don’t forget: reflected glare can also strongly increase light intensity – snow reflects up to 90% of the sun’s rays. We often subject our eyes to this intensity day after day: on a long alpine route in winter I usually take a day to approach, a couple of days on the climb, and then a day to descend back to the valley.
SHADY ADVICE: CHOOSING THE RIGHT LEVEL OF PROTECTION
Aside from looks, when choosing sunglasses you need to know what you’re doing. Start with the correct lens to protect your eyes. Lenses range from Clear to Category 4:
Category 0: 80%-100% transmission. For fashion, indoor use, or cloudy days Category 1: 43%-80% transmission. Low sun exposure Category 2: 18%-43% transmission. Medium sun exposure Category 3: 8%-18% transmission. Strong brightness, light reflected off snow Category 4: 3%-8% transmission. Intense sunshine for high mountains and glaciers
Picking the right lens depends on where and why you’ll be using the glasses. • A quick run in the fells, with clouds overhead? Category 2 should suffice.
• A multi-pitch climbing route in the sun? Fixed Category 3 lenses are perfect.
• Extended alpine routes? A Category 4 lens is essential.
Lenses can be fixed or react to the light. Photochromic lenses react to the light levels (particularly useful in the mountains on mixed days. Finally, there’s polarisation. When light rays hit a flat surface (such as glass, water and snow) they spread out in all directions. A polarised lens reduces glare by cutting out those reflected light rays, while also enhancing colours and improving contrast.
Other features are important to consider: how large are the lenses, and how do the sunglasses fit? I prefer a wide lens, to give me the best possible field of vision. Side shields are vital for mountain-based activities to prevent light entering via the sides rather than through the lenses. Also consider adjustable leashes; I use these when climbing to make sure the glasses say securely in place.
WRAPPING UP
Can you put a price on your vision? Whether you’re in the market for that Euro-wad look, or just after something that stays on, it’s incredibly important to ensure you’re wearing a pair of sunglasses with adequate levels of protection for your adventure. Don’t think your knock-off ‘Ray Beri’ sunglasses that you bought for a couple of quid while on holiday will suffice in the mountains! Buy sunnies that will protect your eyesight properly so you can keep smashing out expeditions for years to come.
Picking shades is easy, right? Throw them on your face, check the mirror. Job done. But if you’re heading beyond the beach and up into the mountains, you need to make sure that they’re protecting your eyes – as well as looking good.
SHADY BUSINESS
64 | CLIMB. WALK. JOIN.
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