Most of us spend a significant amount of time behind the wheel. From daily commuters to motor sport professionals, driving eyewear has become a very lucrative market. Much has been disclosed by relevant motoring bodies about the hazards of eye fatigue, reflective and refractive glare, changing light conditions and times of day while driving, and the impact this has on our ability to react suitably to driving situations. This issue, mivision showcases the lens technology and frames behind the wheel.
Driving Specific Lenses
A recent clinical study conducted by Indiana University, U.S.A., looked at driver reaction times and found that myopes gain five seconds and hyperopes gain two seconds on reaction times when wearing an anti-reflective coating on their glasses.
These findings can lead to the prevention of a lot of accidents and issues on the road. The study also concluded that drivers should wear AR coated spectacle lenses at night because of the better contrast sensitivity resulting in clearer vision and therefore quicker reaction times in critical situations.
For the lens and frames companies addressing these issues, the primary focus is on creating lenses that are able to maintain visual clarity, increase colour contrasts, reduce glare and filter out harmful and distorting blue spectrum light.
“A recent clinical study conducted by Indiana University, U.S.A., looked at driver reaction times and found that myopes gain five seconds and hyperopes gain two seconds on reaction times when wearing an anti-reflective coating on their glasses”
Leading the market for driving lens technology are two companies: Younger Optics and Carl Zeiss Vision – both of whom supply their lens technology to labs and frame manufacturers.
Younger Optics has developed ‘Drivewear’, a lens technology designed specifically for driving. Drivewear provides a precise balance between protection against glare and the amount of light which reaches the eye, with the necessary visual information to maximise the driving task, even behind the windshield of a car. The lenses used are designed to address the visual information in different light conditions, ranging from low light overcast weather, to bright sunlight.
Carl Zeiss Vision’s SOLA Performance Lens Series (PLS) Rx Sunlenses range includes five highly specific lens designs; each with a unique polarised filter with spectral characteristics designed to optimise the visual experience of the wearer for particular outdoor activities. One of these is the ‘Driver’s Seat’ – designed for situations with speed and motion, and hence ideal for driving.
Younger Optics Drivewear uses two of the most advanced technologies found in optics today: Transitions photochromic technology and NuPolar polarisation. Drivewear is marketed as an ‘intelligent’ lens, as it automatically adjusts during varying light conditions.
Its development came from identifying the limitations of polarised lenses, which are good at blocking glare but often too dark to wear when driving; and photochromic lenses, which are great at increasing contrasts such as ensuring traffic lights are obvious even in darkened conditions and work well in light conditions, but struggle when there is a windshield between the weather and eyes.
|Most Popular Coatings for Driving Eyewear
Polarisation has rapidly become one of the most desirable features for driving eyewear. Polarised lenses eliminate glare, enhance colours and accentuate contrast, depth perception and visual acuity. Polarised lenses block 100 per cent of the sun’s harmful ultraviolet (UVA and UVB) rays.
To effectively dispense polarised sunwear, it’s important to clearly identify your patient’s needs. For driving, a polarised lens would allow the driver a more relaxed experience, filtering out the need to squint, alleviating annoying, and potentially dangerous glare.
Often associated for its abilities in relation to water sports, the scope for photochromic coatings is broader, as it automatically adjusts for varying light conditions whilst driving, providing comfort and reducing eye strain and fatigue.
Many eye care professionals strongly recommend glasses with an anti-reflective (AR) coating for night driving. This ultra-thin film, made from zircon and silicon, reduces internal reflections in the lenses. Unlike sunglasses or self-darkening lenses, which block some light, AR-coated glasses actually transmit more light. This improves vision at night and helps distinguish fine details during the day.
In the past, the attempts to combine polarisation and photochromics had failed due to the fact that the properties of the lens weren’t designed to make the two technologies work together in synergy, and hence neither technology was used to its highest potential. Drivewear has changed all that by combining the unique and complimentary capabilities of each of these technologies so that they now work together.
The photochromic properties of Drivewear lenses have been a major step forward, as in the past, photochromics responded only to UV light intensity. Upon exposure to UV light, the molecular structure of typical photochromics, such as the naphthopyrans, will change orientation, and absorb light, however, because car windshields contain UV blocking agents, common photochromics won’t work.
The technology breakthrough needed was to find an array of molecules that would activate by lower energy visible light, not just higher energy UV light. This would facilitate reaction of the molecules behind the windshield. It was also essential to achieve the performance longevity of such molecules. The most important factor was to maintain traffic light colour recognition according to ISO standards.
Younger Optics turned to Transitions Optical Inc. – the leading innovator of photochromic technologies – for the latest developments in visible and UV activated dyes to enhance the Drivewear lens.
Drivewear Transitions SOLFX lenses are the first and only photochromic lenses on the market that darken behind the windshield of a car. The scriptable lenses also feature another breakthrough in the development of a light, high contrast polariser that maintains high polarisation efficiency.
Younger Optics has succeeded in making the polarised and dye package work together to deliver the proper spectral colour results at the varying states of the lens.
Carl Zeiss Vision
From the PLS series, Carl Zeiss Vision introduces ‘The Driver’s Seat’ – specifically designed for driving. These lenses are tailored to allow moderate light transmission for sustained comfort and visibility in varying conditions. They incorporate ‘image intensifier’ filters that improve light adaptation during both bright and low light conditions.
The key feature of the Driver’s Seat is the g-15 lens which is a polarised brown lens (15 per cent transmission and 85 per cent density tint). The brown tint allows for moderate transmission to bring the wearer continual comfort. The brown filter blocks a high percentage of the blue/green spectrum, which results in images being very crisp, vibrant and easy on the eye.
The image intensifier filters improve light adaptation during bright and low light conditions. The Driver’s Seat is available in CR-39 and Polycarbonate (SFSV 2,4,6,8 Base), and other features include a silver flash mirror and back surface AR coating.