Eyes are one of our most amazing features as human beings. There’s more detail and technology in your eye than in that £10k Trek Madone or Specialized Venge. It should therefore go without saying that you should look after your eyes even more than you look after your bike – yes, I mean it.
Unfortunately because of their location, eyes are quite exposed to all kinds of things that can damage them. The best we can do is to put a physical barrier in front of them. This prevents objects like stones and insects flying into them, it’ll also help reduce interference from dust and pollen. I say ‘sunglasses’ instead of ‘glasses’ because as well as the physical barrier we need to reduce the amount of UV rays that reach our eyes. UV rays can lead to cataracts, macular degeneration, cancer and even blindness. The same UV rays can damage your skin too so it’s worth giving that a thought, but for now I’m talking eye protection.
The term “Sunglasses” covers a broad array of different price ranges and styles. There are souvenir shops selling them for a fiver, or you can get a premium brand pair for a couple of hundred pounds. Different frame materials are available from cheap plastic to composites, metals, even titanium. The different lens coatings and tints are enough to confuse most people. In this article I’ll try to help you understand some of the jargon and help you understand what to look for when you go shopping for a new pair of sunglasses.
So why not just buy a cheap pair of glasses? As with most things, you get what you pay for. The technology that goes into producing a pair of sunglasses that have a comfortable frame and lenses that give undistorted, glare free vision is expensive. The materials used are also expensive. If you buy cheap you can end up doing more harm than good because a simple tinted lens can cause your iris to open and let in more light. If this light isn’t UV filtered you are then causing more damage to your eyes than not wearing glasses at all. Fortunately it is relatively cheap for manufacturers to add UV protection to a lens so even at market stalls and petrol stations if sunglasses say they are UV protective they probably are. Interestingly it is also possible to make clear lenses protective against UV rays.
Firstly lets look at frames because there’s less technical jargon to get round. Frame materials are generally either some kind of composite, or a metal. Composite frames are light and flexible. Cheaper frames may shatter or scratch easily and more expensive frames will be more durable. Metal frames are generally more durable than their composite counterparts. Cheaper metals may rust, more expensive brands may be engineered for better flex and fit and even be made of lighter metals like titanium.
The most important thing to look for in a frame is fit, you need to fit the shape of your head to minimise the amount of light that gets around the lens. Wrap around type frames give the best protection from ambient light as do frames with large lens apertures that fit close to your face. More flexible frames should give a better fit. The hinge design can also aid the flexibility of fit. Tension sprung hinges are a good feature and will be invaluable when trying to get the arms of your glasses outside your helmet straps.
Another thing to look for is contact points as most people don’t have perfectly symmetrical faces. The nose piece and stems are where the glasses are supported, if these points are ill thought out then you will be uncomfortable. You should look for features such as silicone pads in the stems and nose pieces. Adjustable or flexible nose pieces may be made of a hydrophilic material (Bolle and POC glasses use this) which absorbs moisture to reduce slipping.
There are also a number of different choices of how the frames and lenses fit together. The main options are with a frame that completely surrounds each lens; giving good protection against scratching if you drop them. Or a half frame that just covers the top of the lens and leaves the bottom of the lens uncovered. This design gives better visibility but does leave the lens vulnerable to damage. Some frames will enable you to swap out lenses easier than others. This can be a great feature, but if you do your homework and buy a pair of lenses that suits your use you shouldn’t need to swap them out anyway.
Lenses are there to help protect you from UV, to reduce brightness from direct light, reduce glare from reflected light, and to help focus certain features. As a cyclist you’ll experience lots of glare from the road and other vehicles, so top of the list of needs is polarisation. Polarisation is a way of filtering out glare. In short all you need to know is polarisation is a good thing and will mean that you don’t squint so much.
Lenses come in different coloured tints and each colour is useful in different situations. As cyclists we need either a grey tint, which cuts down on glare and brightness without distortion of colours and is a good general purpose tint. Or a yellow, amber, gold or brown tint. These colours all have similar properties which are useful for cyclists; reduction in reflected light and better depth perception. The lighter yellow and gold give better colour perception than the darker amber and brown. They are also great for low light conditions, so even when it’s not sunny they can enhance your vision and cut out the UV rays that will still be penetrating the clouds. Worth noting that some manufacturers use a grey lens with a coloured iridium over the top to achieve the same effect as tinting but may end up darker.
Other features to look out for include the following;
Anti Fog, stops condensation forming, usually on the inside. On a cold day the moisture in your breath can condense on the inside of your glasses and make it tricky to see through them.
Hydrophobic/oil repellant coating works in a similar way to the anti fog but is usually used on the outside of the lens to cause any water, or sweat to bead up and run off the lens and prevent it disrupting your vision.
Photochromic lenses sometimes called Reactalite, change the level of tint depending on the UV level. Superb for cycling in and out of tree cover or tunnels. Not so good in the car, because most windscreens now have UV protection so the lenses won’t be hit by the UV and so won’t react as well to the light.
Gradient Tints can have thicker tinting at either the top, or bottom, or both. Ideal for driving as the top can be darker and then you can still see your dashboard. Maybe useful on a bike for seeing your cycle computer?
Scratch Resistant coating is very useful on a composite lens. A Diamond Like Carbon or Polycrystalline Diamond coating will help prolong the usable life of your lenses by preventing scratches that will cause distortion.
Anti reflective coating usually applied to the back will stop ghosting and reflections off the back of the glasses.
We hope that clears up some of the jargon. Maybe you can even use this article to persuade the other half that you really do need to buy that pair of (insert brand name your favourite cyclist wears here). Above all remember that UV protection is number one priority. Good coverage also helps prevent things getting in your eye. Looking good, matching the rest of your kit and bike, and being able to wedge them safely in your helmet vents are all very important too. And if you do wear them on the outside of your helmet straps like you’re supposed to, please remember to take them off before you take your helmet off!
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