“Sunglasses are sunglasses.” An often-heard comment, revealing a common sentiment: Sunglasses are simple devices designed to block the glare of the sun from your eyes. Many people agree with these sentiments. Some even feel paying more than a few dollars for a product perceived as costing a few pennies is a foolish and unwise investment. This is more than a simple misunderstanding.

It’s not TRUE.

At the same time, the public sees the newest technology within today’s cars as the result of very carefully done research, engineering, technology and field-testing. These vehicles enhance the driving experience, offer superior protection from the dangers of unforeseen impact, and include assurance that these special qualities will last the vehicle’s lifetime. Like cars, new technology in eyewear helps to create today’s smart sunglasses. In-depth vision research into exactly how we see, sense and perceive the world is engineered into every one of these new lenses.

Along with advanced filtering technology designed to ensure optimized protection from the sun’s radiation, the best of today’s sunglasses employ new materials that deliver unrivalled optics, durability and comfort. These include the promise that their high-tech protection will also not diminish over the lifetime of the lenses. And, for that unexpected accident, today’s smart sunglasses provide sentry-like protection, helping to avoid eye or facial injuries.

So how do we best convey these benefits to a skeptical consumer before they’ve had a chance to fully experience it for themselves? First, begin by becoming familiar with and understanding the science behind these new smart sunglass technologies. We’ll show that our current, simple in-office demonstrations are no longer sufficient to teach how smart sunglass lenses work. Our role is evolving into that of a solar exposure consultant, a guide to the benefits for activities in which people wear sunglasses.

What Can You Say?

As a sunwear consultant, what can you say? Try… “These new smart sunglasses filter out specific colors of the spectrum and deliver stunning definition, contrast and color enhancement. In fact, the longer you wear them, the more you’ll like them. And they can adapt to changing light conditions. Now, if you put your old tints on, you’ll really see the difference.” To become an effective solar protection guide, what do we need to know to understand how smart sunglass technology works?

Smart Sunglasses – Five Point Filtration Technology

Today’s high-tech sunglasses integrate many technologies to deliver the highest level of protection and performance to the wearer. Specifically-tailored filter recipes (colors with selective absorption of specific wavelengths) are available for just about every activity. One or more of the following high performance components are found in today’s smart sunglasses.

Chromatic Contrast Control filters light of different wavelengths, designed to enhance contrast by modifying color discrimination. For example, the target color of a skeet or clay pigeon is enhanced, while the background sky colors are reduced or suppressed in the Pilla Sports lens.

Glare Control filters both overall and selective brightness, and may include a reduction or enhancement of reflected light. For example, the general-use sunglass wearer can benefit from the safety and comfort aspects of polarized lenses blocking reflected light, whereas a competitive golfer utilizes and requires subtle cues—gleaned from reflections off the grass blades on the greens—to best evaluate ground contours during putting (Nike Golf).

Dynamic Brightness Control creates lenses to rapidly adjust to changes in overall outdoor brightness. The newer photochromic lenses excel here, as they are engineered to not only work effectively behind the windshield of a car, but also can include Chromatic Contrast Control as well (Julbo Falcon lenses, Younger Optics Drivewear lenses).

Effective Solar Protection is critical. This is achieved best when a lens blocks everything that we know to be harmful: UVB, UVA, High Energy Visible Light (HEVL, also known as high-energy blue light), and may include a portion of the infrared, or heat spectrum.

Authentic, in Prescription is designed for every optical office. The special filtration recipe of smart sunglasses is now available to the prescription wearer as well. Many sunglass companies, such as Rudy Project, Serengeti, Maui Jim, Julbo, 7eye etc., offer authentic prescription programs to ensure everyone—nonprescription and prescription wearers—can enjoy identical benefits of their solar protection and color enhancement technology.

For The Life of The Rx is a promise. The benefits of authentic lenses will last the life of the prescription. This is accomplished by confining the proprietary recipe of color filtration, photochromism or polarization within 0.9 mm of the front of the semi-finished lens (Figure 1, Confined Tint process featured in NXT Rx sun lenses). Therefore, with surfacing removing the back surface of the lens, a pair of prescription authentic sunglasses, either single vision or a freeformed progressive, does not suffer any reduction in promised performance. Can you hear the death knell sounding for the tinting of a client’s older-Rx lenses into sunglasses? The fact that they’ll fade, altering and reducing their protective benefits, should be persuasive enough to abandon this old shortcut to solar protection.

To better understand how these smart sunglass benefits are created, we’ll require knowledge of how the eye and brain process visual stimuli.

Looking For An Edge

Imagine being placed in a completely pitchblack and soundless environment. The first thing our bodies become aware of and seek out is the floor beneath us. This is our fundamental sensory border, and it provides the first basic reference for the rest of our spatial awareness. Next, we’ll reach out and wave around with our hands in the immediate space around us—groping and seeking any object that will help tell us more about the structure of our immediate surroundings. With our pupils dilated, our eyes will rapidly roam about, looking for the most subtle distinctions in light versus dark, seeking to find a visual “edge”—an edge that will also help further define the space we’re in.

Nature has made our vision and other senses extremely sensitive to this edge-seeking, which we process as a sensory-stimulus change. Our retinal neurons will fire, or not, in response to border-based stimulus changes. Anything that provokes a retinal neuron to fire will provide the basic building blocks for our brain to process visual information, and improve our understanding of our environment. Our eyes are always seeking these visual edges, and we’re capable of seeing better anytime these edges are enhanced.

Fundamentals of Visual Sensitivity and the Solar Spectrum

Our eyes are stimulated by the visual spectrum, electromagnetic radiation in the range from 400nm to 700nm, which spans the colors from violet to red, respectively. But all colors are not perceived equally. Our eyes contain different retinal receptors. The rods, which are monochromatic in nature, respond to just one wavelength (490nm) in low brightness conditions. There are three other polychromatic receptors, called cones, each of which is stimulated to fire within a limited range of wavelengths. These three receptors define our color vision as a “trichromat”. With medium to high brightness receptors that peak in the short range (420-440nm), middle range (530540nm) and longer range (560-580nm), we enjoy seeing all the colors of the rainbow. (It is no longer considered accurate to refer to these three receptors as blue, green and red.) Each of these receptors will not just respond strictly to light within its target wavelength range.

A receptor’s sensitivity curve is broader, and actually overlaps parts of the other receptor’s sensitivity curves. Because of this overlap, our vision can enjoy a much larger range of colors than otherwise would be the case if these receptors only responded to their primary wavelength range. With this overlap, humans have an overall color sensitivity resembling a bell-shaped curve, with a peak response occurring at 565nm (yellow-green.) On either side of this peak wavelength, our overall visual sensitivity diminishes. The increased ability to perceive more colors from this overlap is advantageous and probably evolved through natural selection to help our ancestors better identify ripe fruit and poisonous berries.

Any wavelength of light from 420nm to 660nm will produce a unique set of responses that combines all three cone types. For the outer range of very short or very long wavelengths, only a single receptor is stimulated and fired. But the advantage of enjoying a large variety of colors is accompanied by a disadvantage: a decrease in our ability to rapidly discriminate color borders, or edges, in the receptor overlap areas. The ability to discriminate colors is referred to as “chromatic contrast,” and is essential toward understanding how different color tints in sunglasses can enhance our visual response.

Improving Vision by Enhancing Edges

After decades of listening to the annual spring sunglass commentators trotting out gray again and again as the “best” sunglass tint, let’s take a close look and see if this old wisdom is really the best consumer advice we can offer.

Sunlight that is filtered by a gray lens leaves the eye’s response curve to color unaltered. Colors retain their natural relationship to each other, and traffic signal recognition remains the same as natural vision—for the “average” person. But in order to enhance our eye’s visual response, we’ll need to emphasize the edge of objects through an alteration of how the eye responds to color. Let’s look at the ways this can be accomplished:

• Change overall brightness (stimulus amplitude—changing the overall intensity of the light.
• Change how we perceive certain colors (changing the stimulus values in selected parts the spectrum) — we can improve visual recognition of a color-edge border by enhancing the target’s primary color, and/or by suppressing the color’s adjoining surround.

By changing the spectral relationship between colors, selectively absorbing some wavelengths more or less than others, sunglass tints can emphasize or suppress the eye’s response to certain wavelengths. This creates a different firing pattern for the cone receptors, and the brain will process this change as edge enhancement. That means different lens filters can be tailored to enhance the visibility for selected activities, such as golf, tennis, clay shooting, or even computer usage.

Visual Response Enhancement:
The Tristimulus Curve and Just Noticeable Differences

The individual and combined sensitivity response of three cone receptors of our eye can be illustrated by the Tristimulus curve (Figure 2). The sensitivity of the short, middle and longer receptors are discernable, along with the overall shape of their combined interaction. Each receptor’s curve overlaps the others, which nature has employed to allow us to interpret more colors than we could otherwise without the overlap. But, all those extra colors decrease the eye’s signal to noise ratio, and reduces our ability to recognize the difference between colors that are in close proximity within the visual spectrum. New Smart Sunglasses will be engineered to enhance chosen activities. From driving to golf, range-shooting to boating, skiing to tennis, the number of different and purposively-tailored sunglass tints is staggering. But the underlying scientific basis for all is a careful change in the Tristimulus curves through an alteration of firing response of the conical receptors. By altering a receptor’s “normal” firing potential, we can create an edge enhancement. Adjoining colors that lie at the threshold known as the “just noticeable difference” can be significantly increased, thereby improving visual response.

That’s the good news. The bad news: Changing neural firing patterns is a change that humans do not always welcome gladly.

Vision Habit: The Experience of Vision

All sensory experience, including vision, is a comparative: we are constantly comparing what we encounter against what we have experienced or what we know. This is one of the basic building blocks in how we learn about our environment through our senses. New stimuli are processed by our brains and compared to our experience. A difference from what is expected is processed by the higher brain centers, and flagged for attention—i.e. “something’s up!” This is why babies are such inveterate explorers—they interact freely with their environment because they have no experience informing them to be otherwise cautious.

Color Space:
A Tool For Analyzing Color Perception

A graphical representation illustrating all the colors that the human eye can see at a single brightness level is called a “color space”, and was originally defined by the (CIE) in 1931. Three coordinate poles, the apices of a triangle, roughly represent the colors red, green and blue, which, through combination, yield all the remaining colors that are possible for us to see. Associating the response of our three cone receptors, which are not exactly centered on the red, green and blue wavelengths, to the specific color perceived is obtainable within this color space graphic. But color perception is also influenced by the type and nature of lighting encountered in the target environment. And color sensitivity is not the same as color selectivity. Our eye has a larger window for a “just noticeable difference” in the green part of the spectrum, as compared with purple colors. Various versions of the CIE diagram are available to help illustrate the effects for individual lighting conditions. Therefore, a color we might favor as superior for indoor tennis—under artificial/fluorescent lighting—may not be as beneficial for playing tennis outdoors in natural sunlight.

We have traditionally referred to tints that alter color relationship as being selectively absorptive. But selective absorption alone does not fully describe how today’s smart sunglasses deliver color enhance- ment and improvements in visual recognition.

When enhancing a customer’s vision through the use of color change (really a new kind of filter), we may encounter resistance. That’s because the spectrum they now see is unfamiliar, i.e., it’s not what they are used to. Even if a vision advantage is demonstrable, your customer may initially react in a negative manner to the simple act of changing what they are familiar with. A quick, in office demonstration can therefore be problematic: It may simultaneously help or hinder showing the benefit for a specific tint recommendation. Do like you do for progressives; tell them to “experience the product for three weeks” to “get used to” the new lens color. This time frame allows neural adaptation to reduce the “flags” that something new and unfamiliar (and perhaps initially uncomfortable) is present.

Start educating your patients now about challenging their old sunglass habits. A good place to begin is also an untapped market, ripe for ECPs to exploit for sunglasses: protecting our children. I’m sorry to say that our culture is totally insensitive to the need of equipping our youngsters with proper, high-quality sunwear. Parents should be told to set the example, and encourage and teach their children about the importance of protecting their eyes from solar exposure.

High Contrast and Optimization of Gray

We’ve already seen that color enhancement using sunglass filters results from combining the effects of enhancing the target color, while simultaneously suppressing background color. Examples are brown tints, as well as rose, purple and amber, which all enhance selected colors, but also suppress others. The future is for new gray recipes to provide uniform transmission, color enhancement and still avoid the pitfalls of overly suppressing adjoining colors. This author expects that when it comes to gray, smart sunglass technology will prove that “you can teach an old dog (or in my case, an old optician) new tricks.”

What Defines a “Comfortable” Sunglass?

You wouldn’t dream of playing 9 holes of golf without properly-spiked footwear. But those same golf shoes would prove uncomfortable in everyday use. So why should we expect that a purposely-designed golf sun tint prove effective and comfortable for general sun wear use? With a change in color relationships, your vision first recognizes that something new and novel has been introduced. But only after wearing it for a while can you decide if this new vision will prove indeed comfortable and an enhancement for golf.

Poorly engineered sunglasses will alter color relationships in a way that promotes retinal receptor fatigue, which we translate as uncomfortable. Presenting the idea of mauve, reddish-brown or intensely-green tinted golf sunglasses to someone whose been wearing grey lenses for years can pose a challenge. Old habits die hard, especially when the media exposes the public to the same old recommendations about gray sunglasses. But even with gray’s track record in general use, it might just be time to apply our latest solar filtration knowledge to this old friend, and take it into the 21st century.

Avoid (S)unfamiliarity

More than ever, there’s an overwhelming amount of information bombarding your customers on the internet regarding sunglasses and specialty lenses. They can become easily confused or worse, inappropriately persuaded as to what might be best for them. Of course, the answer is that no single sunglass can do it all. Therefore it is essential that ECPs keep up on the latest developments and expand their understanding of new smart sunglasses technology.

Help your customers not only protect their eyes from harmful rays, but also to enjoy comfortable, fatigue-free viewing and improved vision in their chosen leisure or sports activities. Avoid (s)unfamiliarity, which is the tendency to repeat and reinforce the same old tint recommendations year after year. We can start by challenging the “wisdom” of the general media each spring and explain how new technology is providing clear reasons to build a sunglass “wardrobe.” By doing so, you will earn and build client trust and loyalty, which are the building blocks of repeat business and your future success.

In an age when our wonderful internet is commoditizing everything, it’s time to position you on SPEC, as a Solar Protection and Enhancement Consultant. Avoid being commoditized yourself. Selling smart sunglasses not only helps avoid (s)unfamiliarity, its just plain smart business.

by Barry Santini
2020mag.com