|Serengeti Destare with Polar PhD Drivers have an amber color with both photochromic and polarized properties.|
There are four kinds of glare and each one requires a different method to correct it.
Light is in constant flux from dawn to dusk. Most people are exposed to light’s variability throughout the day and even over the course of a few hours. Think about golfers on the links from dawn until midday or midday to dusk, the cyclist on the road for six-plus hours during a century ride (a ride of 100 miles or more), or the RV driver heading across the country for vacation. Because light is variable, people need lenses that can adapt and control the light so they can offer the wearer the best and most comfortable vision throughout the day.
|DOUBLE REFRACTION The photosensitive molecules in Transitions’ Optical, Inc.’s Vantage™ lenses are birefringent. That means they double refract. When they are oriented in one direction, they allow light to pass through but as they change their direction, they block the light in that direction. The trick is to get them to align in neat rows so they can orient to block polarized glare. This is the same principle that’s used in plasma TVs, cell phone screens, gas pump displays, and a host of other electronic gadgets today.|
Control is a word that you will start to read about more often in optical articles, brochures, and advertisements. That’s because eyecare professionals (ECPs) now have lenses that really do control light, not just block it. What I’m talking about are polarized photochromic lenses. These lenses incorporate two helpful technologies into a single lens.
Photochromic lenses have long been a popular option for eyeglass wearers because of their light-controlling properties. No matter how bright it is outside, photochromic lenses adapt the lens’ color density to the situation, thereby providing comfort to the eye. Polarization is needed when blinding glare washes out detail and causes eyestrain, squinting, and other symptoms.
The ultimate purpose of a sun lens is to eliminate glare. Why? As amazing as human eyes may be, there are times when they cannot adapt to the light around them. Light that an eye cannot adjust to is known as glare. It varies from simply annoying to completely blinding and any good sun lens needs to control as many kinds of glare as it can, otherwise the wearer will not be fully protected. There are four and each one requires a different method of correcting it.
|Younger Optics offers Drivewear, the first photochromic lenses designed specifically with driving in mind.|
Distracting: This is glare that is more annoying than dangerous or blinding. Distracting glare is often brief in duration. Most people experience it when they turn their heads to just the right position and see the image of their eye and lids on the rear surface of their lenses or some scene behind. It also may be associated with light sources other than the sun, such as headlights and camera flashes. Distracting glare is controlled by using an anti-reflective (AR) treatment on the lens.
Discomforting: Troublesome be- cause it’s due to changing light conditions, discomforting glare can be experienced in direct or indirect sunlight. This is your normal, daily, bright sunshine exposure. Exposure times are longer than distracting glare and can cause eye fatigue. Although annoying, this type of glare would not necessarily be disabling or blinding. The way to solve this type of glare is by using photochromic lenses.
Disabling: Direct sun exposure and indirect sun off bright objects like snow or sand cause disabling glare. This is the glare that you must look away from if you are not wearing a high-quality level of protection. Fully activated photochromic lenses, lenses with a high percentage tint density, or polarized lenses all help cut disabling glare.
Blinding: Caused by light that is reflected off smooth, shiny surfaces, blinding glare can be so intense it can block vision. Think of open water on the brightest day or a snowfield at high altitude. This type of glare can only be controlled with polarized lenses.
|Carl Zeiss’ NXT series provides the highest levels of impact resistance.|
Photochromic polarized lenses are great glare fighters because they knock out three kinds of glare. To control all four types, you’ll need to add an AR treatment to your sun lens.
Most photochromic polarized lenses are designed for outdoor use. This means they adjust from a mid color density to a dark color density.
The new Transitions’ Optical, Inc.’s Vantage™ lens is the first of its type. It offers not only a variable tint, but also variable polarization. I like to think of this lens as having a school of fish inside. You know those television nature shows that are shot underwater? They always show the giant school of fish and when they are all swimming in one direction, all you see are fish, but then they all change direction at once and you see the water and sun beyond them.
Well, the Transitions Vantage lens works in a similar way. The lens contains photochromic molecules that absorb ultra-violet (UV) light which can make the lens darker. The molecules also do something amazing as they absorb UV-they change their alignment from a random pattern into neat rows, and as they do, they also turn in one direction. With the photosensitive molecules now in neat orderly rows, they act like a polarizing filter. By having variable molecule direction, you have a lens with variable levels of polarization. For the first time, there’s a photochromic lens that can become polarized when you need it and virtually clear and non-polarized when you don’t.
|Transitions Vantage lenses contain photochromic molecules that absorb UV light which can make the lens darker.|
MORE GLARE FIGHTERS
In the dark-to-darker sunglass category, there are three choices.
Younger Optics offers Drivewear’, the first photochromic lenses designed specifically with driving in mind. Drivewear lenses use Transitions photochromic technology.
This high-efficiency, polarized lens adapts from a high-contrast green/yellow in low light, to a copper driving-specific tint behind the windshield, to a red/brown for outdoor full sun. Drivewear lenses are available in plano and prescription.
Carl Zeiss Vision, Inc.’s NXT’ series is made with Trivex’ material, and provides light weight, great optics, and the highest levels of impact resistance. Take the advantages of Trivex and add photochromic and polarization technologies and you have a lens that takes light control to a new level. The NXT series is available from Zeiss in a wide range of prescriptions in single vision and progressives. In polarized-photochromic, the Zeiss NXT comes in traditional gray and brown.
Also based on NXT technology, Serengeti offers its Polar PhD™ lens series. Building on its reputation for providing the very best in driving lenses, Serengeti Polar PhD Drivers’ have an amber color with both photochromic and polarized properties. For a general-purpose lens, Serengeti has the PhD CPG™ (Cool Photo Gray). Most models in the Serengeti PhD series are Rxable.
Join the battle against glare and offer these “œGlare Fighters” to your patients.
John Seegers is a licensed optician at Ryan Vision Center in Henrico, VA, and the creator of opticianworks.com.
WHERE TO FIND IT:
Carl Zeiss Vision, Inc.
800-905-2240 ext. 1012 • zeiss.com/lenses
800-905-2240 ext. 1062 • serengeti-eyewear.com
Transitions Optical, Inc.
800-905-2240 ext. 1068 • transitions.com
800-905-2240 ext. 1079 • drivewearlens.com