Buyers Guide To Sunglasses
Our eyes are ten times more sensitive to UV than our skin. Good quality sunglasses or goggles protect your eyes from both UV-A, UV-B and UV-C rays as well as flying debris and foul weather, keeping your eyes safe from short-term damage and the long-term possibility of developing cataracts. As with all technical equipment, good quality eye protection is packed full of science and innovation which can lead to a baffling array of terminology so here is a simple guide to help you choose the right ones for you……
Why do I need to know about visible light and invisible light?
Visible light is effectively glare; it doesn't always have the same intensity according to the weather, climate, terrain, etc., but can still affect your eyes, causing fatigue and sometimes a temporary interference to vision. Invisible light refers to ultraviolet (UV) and infrared radiation, which can cause burning, long-term vision issues and dehydration. Good quality sunglasses will protect you from both, which is especially important on high UV index days and at high altitude. Look for the CE UV400/UKCA mark to confirm the glasses have been correctly tested.
What is the difference between regular sunglasses, sports sunglasses and glacier sunglasses?
Regular sunglasses are generally designed to look good, but durability isn’t really a consideration. Sports sunglasses are designed for comfort, flexibility and impact resistance. They will have key features allowing them to fit better and have lenses that work well in a particular area; for example eyewear designed for watersports will have polarised lenses, or perhaps glasses designed for cycling or trail running will have the bridge mounted lower, allowing the wearer protection when they look up. Eyewear designed for high altitude will have lenses that reduce glare and a wraparound design and/or side panels offering maximum protection from UV and weather. Never wear Category 4 High Altitude sunglasses while driving – the light reductive lens makes them extremely dark, you lose critical side vision due to their shape and in the UK, you are unlikely to be insured if you have an accident.
Should I carry sunglasses or goggles?
Depending where and when you are going you may need both! They may be rare but if you find yourself out in the Scottish hills on a bluebird day in winter the glare can be pretty intense so sunglasses are definitely a good idea. More likely though, is that the wind will be pretty savage as you get higher and having ice crystals blown into your eyes are no fun at all so goggles will provide the best protection. Always carry both in an Alpine environment or on expedition. More and more folk running ultra’s are carrying clear goggles to protect their eyes from savage winds too. Of course, mountains aren’t always sunny! 50% of the sun’s radiation can pass through fog and some types of cloud so it’s best to wear eye protection even when the sun’s not out.
What are the differences between lenses?
Oooooh, this is a VAST area to explain as each manufacturer uses different terminology. A key area to look at are what the lens are made of. The reason regular glasses are made of glass is because it offers the best ocular clarity and scratch resistance however, they are very heavy for sports and can crack when impacted. Polycarbonate lens are much lighter, strong and offer good ocular clarity - the thicker the lens the more durable. A photochromatic or reactive lens will darken automatically when exposed to bright light. It is worth noting that back in the day, older photochromatic treatments were a coating and sensitive to temperature rendering them useless in extreme environments. These days, quality lens are created using a heat treatment which not only improves ocular clarity but means they are not affected by temperature. Polarised lens substantially reduce glare making them ideal for use on the water, however, this can reduce visible definition on snowy terrain. Some mountaineering specific glasses and goggles come with the option of polarisation and some offer a unique form of glare control by using half polarisation; cutting light from underneath the lens but maintaining terrain clarity.
What does the Filter Index or Lens Category mean?
The filter index or sun protection category is pretty much the same thing, both are determined by the quantity of visible light that they let through the lens. The lower this transmission, the darker the lens and it's this tint that affects glare but not UV radiation. there are five categories rated on a scale from 0 to 4, based on the ascending percentage of filtered light.
Category 0 – are clear, allowing 80 – 100% of visible light through designed for comfort and aesthetics.
Category 1 – are lightly tinted, allowing 43-80% of visible light through and are ideal for use in low light levels.
Category 2 – are moderately tinted, allowing 18-43% of visible light through making them ideal for average light levels.
Category 3 – are a dark lens, allowing 8-18% of visible light through for use in strong light levels.
Category 4 – are a very dark lens allowing just 3 – 8% of visible light through so are only suitable for exceptional bright light levels. Do not use them for driving.
Is the colour of the lens important?
Almost all of the lens surface colour on the outside of the glasses we sell has no impact on vision – it’s just there to make you look good. The ocular magic happens inside the lens, so it is only the colour of the lens itself that affects how much visible light reaches your eyes. Darker lens shades like brown, grey or green are intended primarily to cut through the glare and reduce eyestrain in moderate-to-bright conditions. Lighter lens colours like yellow, amber or rose excel in moderate- to low-level light conditions. They provide excellent depth perception enhancing terrain in tricky, flat-light conditions and make your surroundings appear brighter.
Do sunglasses come in different sizes?
Yes. We are all individual; we all have different sized heads and differently shaped faces. Some styles come in different sizes, others are made to be smaller, others are made to be larger. At first glance it can be pretty difficult to tell which ones are which so don’t be afraid to ask. Sunglasses can have the best features in the world but if they are not the right size for you then they are neither going to protect your eyes properly nor be a good investment. It’s really important to take time to try on different styles as they will sit differently. Many have soft mouldable arms that will fit comfortably around your head and the weight distribution should be equal between these and your nose. Your eye lashes shouldn’t touch the lens and don’t forget to move your head around to make sure they don’t shift as this could cause friction points when used over a prolonged period of time.
Can I get my sunglasses repaired?
Yes! We stock the fantastic French brand Julbo for the very reason that they have a superb repair facility right here in the UK. Julbo are also committed to keeping spares for all their discontinued models for five years after they cease manufacture to aid repairs. Julbo also manufacture their frames using 30% recycled content with 80% of their range made in Europe to reduce their carbon footprint and ensure smooth supply.
Top Tips:
- The three key areas to think about when buying eye protection for active sports are: Grip, Fit and Lenses.
- If you are planning on wearing your sunglasses or goggles with a cycling, kayaking or climbing helmet then bring it with you to try both together.
- If you are buying online than don’t forget to check out all of the frame measurements to ensure the correct fit for you.
- If you are using OTG goggles, use an anti-fog treatment on your glasses to stop them fogging up.
- Keep your sunglasses in a case to avoid scratching and clean with a microfibre cloth to keep them working as long as possible. It’s obvious, we know, but it’ll save you a stack load of money in the long run AND it’s better for the planet!
Outdoor Gear Chat Podcast
Take a listen to our Outdoor Gear Chat podcast Episode 22, all about sunglasses, where Cathy and Wayne talk with Barnabé Grison, International Area Manager for French outdoor eyewear specialists Julbo
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