The October issue of Sailing World Magazine has a great article written by Rachel Johnstone. I thought it would be worth while forwarding it on:
When I finally broke down, agreeing to ditch my cheap, generic sunglasses for the real deal, all I knew was that they should be polarized and filter out all ultraviolet rays. I avoided the meticulous thought process that should go into buying quality eyewear and quickly selected a pair, deeming them “good enough”. Acura Key West Race Week was rapidly approaching, and so long as my new shades protected my eyes and let me spot puffs on the water, I was a happy camper. But my eyes have been opened to the abundance of choices available in colored lens. It’s a choice that’s more important than you may think. Lens color is a key factor to the sunglass-wearing experience; the amount and type of details the wearer sees on the water vary with each hue.
“Color perception varies from person to person”, says Oakley’s Andy McSorley. “It is solely opinion based.” Nonetheless, he adds, specific colored lens do perform better in certain conditions.
Let’s start with grey, a neutral color and good, all-purpose lens tint. “Grey is the most universal”, says Steve Rosenberg, of Kaenon Polarized. “It does a great job overall.”
Grey lenses block the sun’s brightest rays without altering one’s color perception, giving the wearer a darker version of what he or she would see with the naked eye, or the most natural view. Many people, says McSorely, prefer grey lens for days with intense sunlight because, despite identical light transmission rates, they believe grey lenses to be darker than colored lenses, which induce a color shift and make reds and greens stand out.
Of all the light waves interacting with our eyes, those at the blue end of the light spectrum are most powerful. Cones in the eye’s retina read color, and its blue light that dominates our vision, washing out our perception of other colors. Minimizing this blue light and enhancing other colors, such as red and green, is said to improve visual acuity.
“Blue light can limit the ability to focus, creating chromatic aberration or blurriness, especially in aquatic and snowy environments where blue light is prevalent,” says Colin Smith, of Revo.
“Because light waves are at their most powerful within the visible blue portion of the spectrum, the most noticeable effects on visual contrast occur by modifying visible blue light transmission,” says McSorely. In order to knock down blue light, however, there must be a color shift. If the wearer doesn’t mind an altered view of the world, there are many different lenses that highlight specific colors and diminish others, which is extremely effective in variable-to-low-light conditions.
Copper, amber, or bronze lenses are ideal for variable light conditions because contrast created by the lens heightens visibility. “Contrast works by highlighting color and separating light from shadows,” says Rosenberg. “It defines slight details in tonal colors, such as the water’s surface, which is otherwise one color. Breeze and wave height versus little wind and flat water create darker or lighter water surfaces.”
Such contrast, adds Rosenberg, determines how sailors see breeze velocity and direction, as well as current.
Because of color shift, and the wearer’s ability to distinguish distant details easily, copper lenses work well in an environment with dark or grey water. They are also very easy on the eyes, as they don’t cause lasting color distortion.
Yellow is another lens color used to enhance contrast and block blue light. Yellow is ideal reading details in overcast, low-light conditions. Yellow lenses excel in a mid-range level of darkness because of the higher light transmission rate, says Rosenberg. It’s the “sweet spot” for those sailors who require and want specific and extreme contrast. Being able to cut through the atmospheric haze allows the user to better see puffs fanning across the water’s surface.
Although different colors perform better in different light conditions, the experts insist that ultimately there is no right or wrong decision when it comes to colored lenses.
“Tints do have a scientific attribute, but each of us is different,” says Rosenberg. “We have different eye colors, different light sensitivity levels, and we do indeed see things differently.”
Lens tint is a personal choice based upon light conditions and the types of information the user wants, adds Rosenberg. “More contrast isn’t always best; it’s a personal; choice.” He says. “This is the trend we see with the best sailors: grey tens to be a favorite of the more intuitive, seat-of-the-pants sailors, and contrast-enhancing colored lenses tend to be favored by the more analytical.”