The most important factor when buying a pair of running polarized sunglasses is to ensure they offer full protection from both UVA and UVB radiation. If you are going to be wearing your sunglasses for long periods of time whilst running or walking and you are working up a sweat, then you also need to consider comfort, fit, polarization, anti-fogging and lens tint.
Specialist running glasses feature non-slip nose pads, super-lightweight frames, interchangeable lenses and careful design to ensure proper ventilation and prevent fogging.
If you are going to be running in different lighting conditions then you need to consider purchasing polarized sunglasses that can cover all your needs.
Dark Tints like blue/grey/green/brown are better for bright and sunny conditions and are most comfortable for the eyes in harsh light.
Golden Tints like yellow, gold and amber tints are much better for low-light conditions as they filter blue light out and make it easier to for you to see the bumps and edges in any terrain.
Polarized lenses are great for very bright light conditions as they cut down on the glare from the sun reflecting off salt flats, pavement and sand.
Clear: Use in dark or windy conditions when you want to stop your eyes from tearing when running.
You should only buy sunglasses that protect against both UVA and UVB radiation. Too much exposure to UV over a short amount of time can cause photokeratitis, which is basically sunburn to your eyes. Long-term exposure to UV rays can cause permanent damage, so ensure that your sunglasses offer full UV protection.
In humid or rainy conditions or where you might be working up a sweat you want to choose frames that offer good ventilation to prevent your sunglasses from fogging up on you. Choose a frame that hold the lenses away from your face so that air can circulate freely, and also consider anti-fog coatings.
If you are taking part in a sporting activity then it’s sensible to make sure that your lenses are made out of a shatter-resistant material, a polycarbonate rather than traditional glass or plastic for example. Also consider what your sunglass frames are made out of – the more flexible then the less likely they are to break when dropped in your jammed race backpack.
Also consider the fit and comfort of wearing your sunglasses for a long race, you may want something lightweight, maybe with rubberized nose-pieces and potentially with adjustable earpieces to keep the glasses in place when running.