Boaters have been aware of the advantages of polarized glasses for more than 30 years, but the new generation of shades definitely seems to have a leg up on the glasses most of us are used to. One of the reasons is the selection of tints available that help you to see better in various conditions.
Much of the newer technology centers on how colors are processed by the eye. Light enters through the pupil where it is focused on the back of the eye at the retina. The retina has two types of “light meters,” so to speak, called rods and cones. The rods ascertain the intensity of available light while the cones distinguish between colors. The eye recognizes wavelengths between about 400 and 700 nanometers as color. (A nanometer is a unit measuring length equal to one thousand millionth of a meter. Light waves are less than one-hundredth the diameter of a hair or a piece of paper.) The color spectrum progresses from violet at the shorter wavelengths through blue, green, yellow, orange, and ultimately red. The eye easily processes yellow light, in the middle of the spectrum, while darker colors on either end of the spectrum provide contrast. During bright-light conditions, too much yellow light reaches the eye, resulting in “glare” and colors appear to be washed out. On the other hand, during low-light conditions objects do not reflect enough light so that their color can be determined and appear only in shades of gray.
Manufacturers have learned that by tinting their lenses, they can take advantage of the properties of light. Lenses tinted yellow gather more light and enhance the blue colors, adding contrast during low-light conditions. During bright-light conditions, glasses that are tinted in shades of brown (copper, amber or vermilion) block the mid-range yellows associated with glare and also add contrast—these are the colors that many say work best on the flats. Gray lenses preserve natural colors while also adding contrast by enhancing the darker colors—they’re good all-around, and this hue with a mirror coating for added reflecting of glare is a favorite with offshore skippers.
Most sunglasses block the harmful ultraviolet (UV) rays that can cause cataracts and damage the eyes. The premium manufacturers integrate UV filters into the lens as one of the inner layers. These UV filters will not rub off, fade or become ineffective because of scratches or abrasions, as is often the case with the less expensive process of merely coating the lens.
Glare is the major problem for anglers who sight-fish. Sunglass manufacturers use a polarizing film that blocks horizontal glare, and this is what allows you to see through the surface. As with the UV process, in good glasses this polarizing film is sandwiched into the center of two protective outer lenses for durability.
Manufacturers incorporate a variety of new technology. Action Optics makes both single-vision and bi-focal prescription sunglasses with photo-chromic lenses that automatically adjust to changing light conditions—you can wear them indoors and out. Costa Del Mar of Ormond Beach, Florida utilizes what they call Wavelength Absorption for Visual Enhancement—WAVE—to _reduce glare while increasing the transmittance of selected green and orange-red wavelengths, which they say gives an advantage on the flats. H2Optics, now a part of the Bolle line of sunglasses, incorporates an anti-reflective coating on the back _of their lenses to further reduce glare. Maui Jim utilizes what they refer to as Polarized Plus technology to also block glare from above, below and behind the glasses. Ocean Waves of Atlantic Beach, Florida, sandwiches a mirrored coating between two glass lenses to protect it from scratching—again, the mirror cuts more glare than polarizing alone. Kaenon polarized sunglasses are available in seven varying degrees of light transmission, as well as a proprietary new resin lens material the company says blends the optical quality of glass with the impact-resistance of polycarbonate.