Cycling safety is always an important topic to discuss, and includes more than helmets and body armor. Performance sunglasses are a crucial, but often overlooked, component of your protective arsenal. Sunglasses protect your eyes from flying debris and harmful radiation that will damage your vision if you are spending hours each week on the road or trail.
There is much more to a performance lens than style, and the color of a lens says a lot about how it will perform in different environments. The most basic sunglasses simply reduce the amount of visual light that enters the eye, while advanced lenses feature polarization, contrast enhancement, and ensure an accurate visual representation of the world around you. A range of lens shadings from clear to black will allow any percentage of light through the lens. Clear lenses allow the most VLT (Visual Light Transmission)—between 80 and 100%. Tinted lenses are designed to block out certain spectrums of light and can be advantageous for certain sports.
Oakley, for instance, offers a wide range of replacement lenses for their Radarlock series of sunglasses. Each lens is purpose built depending on use, and all come with a hydrophobic coating to repel water and sweat. Radarlock lenses filter out 100% of harmful UVA/UVB rays with wavelengths up to 400nm. Visible light is between 700 and 400nm while UVA and UVB radiation is a shorter wavelength between 400 and 290nm.
Clear: Beneficial in low light situations. Offers accurate color perception with no tinting. 93% VLT means it’s best for night use when you still want to protect your eyes from flying objects.
Yellow: Best in flat or low light. On an overcast day, these allow for 90% VLT, cutting down on diffused light permeating cloud cover.
Persimmon: A good intermediate, this lens allows 61% VLT with a red tint that reduces eye strain and improves road visibility by offering a high contrast view by filtering out certain color spectrums.
Red: Similar in color filter to the Persimmon’s lens, this Radarlock only allows for 30% VLT. Do not use the red tint lenses if you are concerned about accurately perceiving color in your surroundings.
Blue: This 10% VLT lens offers true color perception compared to the red lens for brighter situations and helps define contours and edges with a better depth of field.
Black: For those not interested in the blue tint, this lens also blocks out a majority of light with 10% VLT and has an Iridium coating to reduce glare.
Weather is variable though, and you don’t necessarily want to be swapping the lenses out of your frames for every ride, or halfway through your ride. In this case, something like the Photo Vent lens might interest you. Offering variable shading, this lens can block 10-66% of VLT by automatically darkening as it receives more visible light. Oakley Photochromic lenses boost contrast, even in low light conditions.
For extreme light situations, polarized sunglasses are always a popular option. The Radarlock option allows 9% VLT while also completely blocking out light reflecting off of horizontal surfaces. When sun reflects off of the road into your eyes, the light becomes polarized as it bounces off the surface. Polarizing filters in sunglasses can filter out light that is aligned in this manner, drastically cutting down on glare. The same happens with light bouncing off of water and snow, which is why polarized glasses originally became popular for boaters, anglers, and skiers.
Oakley provides a wide array of interchangeable lenses offering tons of flexibility, such as the Radarlock Path lenses referenced in this guide. Eyewear style is obviously a factor as well, and everyone has his or her own taste, so don’t think you have to stick with these. With the knowledge of reflected light, the differences between visual light transmission, and ultraviolet light and their wavelengths, you can look at all performance glasses with expert eyes and find a pair that are tailored to your riding requirements and sense of style. Use this guide as a reference when selecting sunglasses based on tinting, but be aware that the VLT will vary from company to company, so check the published numbers for the lens you are interested in. Some glasses, like the Lazer Magneto M1 are an affordable option with 3 lenses included, providing flexibility without forcing you to purchase each lens separately.
A lot of design and technology also goes into lens manufacturing with the design and implementation of curvature. Performance glasses tend to have more curvature than lifestyle glasses in order to protect the side of the face and keep sunlight from sneaking in around the edges of the glasses. With increased curvature, comes the potential for distortions at the outer edges of the lens. More expensive glasses will have higher precision and tolerance in the lens that cuts down on distortions. Oakley advertises their High Definition Optics to illustrate the testing all Oakley glasses undergo to guarantee distortion free vision. Oakley also goes above and beyond; complying with ANSI standards for impact protection with safety glasses. High velocity and high mass impact testing eliminates the possibility of lens shatter on impact.
If you require a prescription, Smith Optics has designed a sweet prescription lens system. The Ocular Docking System can be added to their Pivlock series of sunglasses, turning compatible glasses into performance prescription eyewear. Just take the Ocular Docking System to your optometrist and they can set the lenses up with your prescription.
With so many options, you can fine-tune your eyewear to suit your personal preferences while protecting your pupils and keeping the rubber side down.
Rubber Side Down is a weekly column dedicated to the fledgling cyclist in all of us. Art’s Cyclery Web Content Editor, Brett Murphy is not a professional cyclist, and doesn’t try to masquerade as one either, but he does love to ride bikes. Whether you are clipping in for the first time or counting down the days until your first race, read on, learn from his mistakes, and keep the rubber side down.