KONA, Hawaii -- Slashing through steep mountain trails at over 20 mph on a finely tuned bicycle with leaves and branches whipping at your face and roots and rocks biting at your tires requires a wee bit of concentration. It also necessitates your ability to see the details of the trail -- and quickly, mind you -- to stay on your mount.
Whether it be the specifics of dirt trails, asphalt roads, ocean waters or even the lines in a golf course, optic science has stepped in to provide a way to filter out color wavelengths that will limit your ability to see clearly, balancing the right colors for the right environment.
Oakley, which showed off its ever-growing line of lens tints ahead of the 2013 Ironman World Championship in Kona, Hawaii, last week, has now grown its specified line of tints to over 70, with even more in-sport specialization on the way, says Scott Betty, Oakley's global director of optics.
In Kona, the tint of choice -- one of the relatively newer options in the Oakley line -- was the OO Red Iridium Polarized lens, which balances out the colors coming to the eye through the lens, offering a "neutral gray" tint that allows details in asphalt to appear more vivid.
Jenny Fletcher, a world-class triathlete, says with the proper tint she can relax her eyes and facial muscles. "The lens feels clear and vivid, which helps me save energy," she says. "It is all about relaxing and any energy saved is substantial."
But while a steady gray may prove scientifically accurate for Fletcher and asphalt sports such as the Ironman that include road biking or running, hitting the mountain trails on foot or two wheels could prove dicey in the same tint.
"You don't play soccer in a baseball cleat," Betty says. "It is not one size fits all. We design specific lenses for specific environments, tuning them so you have the right amount of color based on the color spectrum."
On a dirt path, the array of yellows, oranges and reds seen in the natural environment -- there is nary a blue color found and the green is only in the leaves of the foliage off to the side, not something you're worried about flying down the trail -- mix into a dirty brown. By filtering all other colors other than the most dominant, the VR28 Black Iridium -- recommended for mountain trails -- plays up reds, yellows and oranges, heavily filtering the darker colors. The optic science allows you to discern the details in the ground's muddied dirt, to see whether the soil is loose or hard and where exactly the root stops.
A typical sunglass lens will allow in 10 percent of all light, across all wavelengths. The VR28, for example, allows in 35 to 40 percent of reds and yellows, but just above 8 percent of all blues.
Across 70 different tints those ratios vary widely, from the greens of golf courses to the blues of the water. The Bronze Polarized tint allows you to gaze five feet into the water and helps you discern differing currents. That tint runs almost opposite of the needs of the VR28.
Jenny Kalmbach, a world champion stand-up paddleboarder, says when she's dealing with a channel-crossing race she "reads the currents and finds the best line." A tint tailored to blue detail amplifies that for her.
To get these differing qualities, Oakley manufacturers all its own lenses at its Foothill Ranch, Calif., headquarters, selectively "blocking bad light and transmitting good light," says Ryan Saylor, director of optical technology. Getting to that point, though, varies.
Each lens is an impact-resistant proprietary polycarbonate mix -- dubbed Plutonite -- that allows the rare property of transparency. Each mix uses between four and 20 different dyes, organic dyes (platinum or gold filters often require organic dyes) or basic pigments to create the exact tint that will absorb certain color wavelengths, while letting others through to the eye. Coatings, such as the chrome-looking compound iridium shields even more light and polarization coatings offer the ability to reflect light waves that cause glare.
To find the ideal mix, engineers completely map an environment -- similar to matching paint chips at Home Depot -- to determine the "colors we want to see and others we don't," Saylor says. Then comes a specific color spectrum for each environment that leads engineers to determine the best absorbers for that exact "paint chip." The most complex tints aren't actually the ones where they need to filter out plenty of one color spectrum while leaving the other end alone. Rather, the complexity arises when the lens need to form an even color for the eyes -- such as the OO Red Iridium that creates a neutral gray to provide asphalt details. Where the trail tint of the VR28 may have five different absorbers, the OO Red pushes 20.
As Oakley's science evolves, expect the specificity to grow, with tints created to let MLB players better determine the movement of red baseball seams earlier or anglers see deeper into water with tints created specifically for salt or fresh water. Athletes, though, don't fret over the detailed optic science when careening down a mountain trail. They're simply grateful they can see the bike-flipping roots in their path.
Tim Newcomb covers stadiums, design and technology for Sports Illustrated. Follow him on Twitter at @tdnewcomb.