Drivewear brings together two leading lens technologies, NuPolarÒ polarization and TransitionsÔ Photochromic Materials, to create an entirely new category of lens. In marrying these two technologies, the product that emerged was more than the sum of its parts. That is, although standard polarized lenses do a good job of blocking glare, most are too dark to meet the range of conditions encountered in driving and while traditional photochromic lenses have worked well for people moving between indoors and outdoor, they do not darken significantly behind the windshield of a car (since the windshield blocks the ultraviolet [UV] light that activates the photochromic material). Nor did photochromic lenses offer polarization which is the only way to block blinding glare.
To create a lens that would assist visual function across this wide range of conditions my company, Younger Optic, contributed its excellent polarizing filter, while Transitions Optical offered world-class photochromic technology.
Developing the Lens
In the past, polarizing filters were by nature limited. Light-colored polarizers (e.g., light green or sky blue) were attractive but they typically provided poor polarization levels. When checked with standard glare demonstrator, they offer hardly any glare reduction at all. So, the first requirement for Drivewear was a polarizer that was not only light in color but also highly efficient. After much testing and experimentation Younger Optics was able to develop a high-contrast, yellow-green color that had the necessary level of polarization efficiency.
Car windshields absorb most UV light; so the UV inside a car, even when the car is in bright sun, is insufficient to fully activate traditional photochromic materials. The development of Drivewear lenses required the creation of a photochromic dye that could be activated by short wavelength visible light as well as by UV. Because one wants traditional photochromic lenses to be unreactive to visible light (so as to prevent unwanted darkening indoors), creating the photochromic material for Drivewear presented a very difficult and unusual problem for Transitions Optical and its chemist.
The lenses substrate material that many companies, including Younger Optics, use is different from that used by Transitions. Marrying our technologies required us to reformulate many of the basic techniques that each company had perfected for its individual product. Entirely new casing cycles and chemistries were developed that would work not only in the development of polarized lenses but also in the secondary process by which Transitions adds photochromic capability.
As a general rule, polarizing film does poorly when exposed to the high temperatures of the photochromic process. So Younger Optics had to develop a heat-resistant polarizing film that maintained the necessary high efficiency and color fastness of its other polarizing film. The new technology developed is so successful that it has been incorporated into NuPolar’s standard line. As a result, NuPolar products can now successfully receive antireflective (AR) coating and stand up to high temperature hard coat processing.
No performance benefits can come from adding mirror coatings to Drivewear lenses, and therefore its makers recommend againist it. Anti-reflective (AR) coating, however, can enhance Drivewear lenses' functionality. Back surface AR coating reduces annoying reflections from behind the wearer. While back surface AR coating provides the biggest benefit, many laboratories prefer to coat both front and back. There is no problem doing this with Drivewear.
Color Technology Brings Driving Comfort
When light intensity is low, the natural or rest state of the Drivewear lens is a light yellow-green color that maximizes the amount of useful light transmitted. (Figure 1) Thus, when it is overcast, the lens allows as much light as
With increasing light levels, Drivewear begins to darken to a deep copper color, which many drivers find to be the most comfortable and best color for driving (Figure 2). This is not surprising, because this color removes excess light while highlighting reds and greens for good traffic signal recognition.
In bright outdoor light (which is rich in UV),
Who Can Benefit?
Drivewear lenses are of course, designed with drivers in mind. There are other patient groups to consider, however, when offering the lens. For example:
Senior: Older patients have slower reaction times and so need every advantage they can get. Drivewear’s greatest benefit for older drivers is the increased contrast in overcast conditions. Increased contrast also allows red and green traffic lights to remain noticeable in darkened conditions. This may even help elderly patients notice a light change up ahead sooner then they might otherwise.
Parents: Drivewear is also helpful for the busy parent. In a car with children talking, televisions playing and cell phone ringing, knowing that you have the best available vision is knowing you are taking the best possible care of your family. I personally would love to see the day when just as any person immediately puts on a seat belt when getting in the car people put on their Drivewear lenses.
Outdoor Enthusiasts: A foggy morning round of golf can have transformed by mid-morning into a very bright, sunlit game. Individuals who experience a range of changing light conditions will readily appreciate the light, high-efficiency polarizer of Drivewear that allows optimum vision in low-light conditions as well as in bright light.
Professional Drivers: The men and women who spend most of their waking hours behind the windshield of a vehicle experience a much wider range of light and weather conditions than the rest of us. Whether its glare from the road, the sun, or oncoming traffic, professional drivers experience it all – and almost every day. Only Drivewear is designed to provide these people with the ability to see their best in such a wide variety of circumstances.
Drivewear, however, is not for night driving, as much highway safety experts agree that no tint should be used for driving in the dark. (AR-coated clear lenses are the choice for night driving.)
Drivewear and Your Practice
The target market for Drivewear is literally anyone who drives a car. Plano Drivewear is available for emmetropes, while semi-finished Drivewear blanks are available to accommodate prescription powers from +8.00 D to -6.00 D in both single vision and ImageÒ progressive (1.00-3.00 d adds) design. Indeed, Drivewear is a “no-brainer” second pair sale. While patients often don’t see why they should pay a lot for high-quality sunwear, it becomes clear to patients when they see the unique features of Drivewear lenses.
In addition, as an extra benefit, Drivewear lenses block 100% UVA and UVB in all lighting conditions.
The high-quality polarized lenses that broke into the prescription lens market in the 1990’s quickly set the standard for sunglasses. Prescription polarized eyewear is often an expensive item that patients resist. But the combined technologies of Drivewear set it apart from the rest of the marketplace and make the price/value equation attractive to patients. When dispensing Drivewear lenses, practitioners can feel confident that they are prescribing a product that is unique and unparalleled in either the prescription or nonprescription sunwear area.
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