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"Go-To" Progressives for Your Dispensing Toolbox

By Gary Heiting, OD

Release Date: February, 2014

Expiration Date: March 1, 2015

Learning Objectives:
Upon completion of this program, the participant should be able to:

  1. Learn how to choose the best suited progressive lens technology (conventional vs. digital), based on individual patient needs.
  2. Learn how modern conventional progressive lenses use advanced design technology to deliver some of the same benefits as digital progressives.
  3. Develop a simple strategy for selecting and fitting progressive lenses that provide the best combination of wearer satisfaction, value and profitability.

Faculty/Editorial Board:
Gary HeitingGary Heiting, OD, is a licensed optometrist and is senior editor of allaboutvision.com. Dr. Heiting received his Doctor of Optometry (OD) degree from Southern California College of Optometry in 1984 and has held clinical positions at Ophthalmic Surgeons & Physicians, Ltd. (Tempe, Ariz.), Park Nicollet Medical Center (Minneapolis, Minn.) and Eau Claire LASIK (Eau Claire, Wis.). Dr. Heiting has also served as director of education and director of product development at Pentax Vision, Inc., a subsidiary of Pentax Corp. (Tokyo, Japan).

Support:
This course is supported by an educational grant from VISION-EASE LENS

Credit Statement:
This course is approved for one (1) hour of CE credit by the American Board of Opticianry (ABO). Course SJHI026


Generally speaking, having plenty of choices is a good thing. But sometimes too many options can lead to confusion, second-guessing and less than optimal solutions.

One could argue that a state of too many options is what we find ourselves in these days in eyecare when it comes to selecting and recommending progressive lenses.

Progressives are available from many manufacturers in every lens material and treatment imaginable, and the choice of progressive lens designs has blossomed from a relatively simple one—"soft" versus "hard" designs—to something far more complex.

In addition to multiple progressive corridor lengths, we now have three broad categories of lens designs to choose from: conventional progressive designs, free-form (digital) progressive designs and personalized (individualized or customized) digital designs.

To ensure we're all on the same page, let's review the definitions of these design types. Conventional progressive designs: In conventional progressive designs, the progressive power of the lenses is molded onto the front surface of a series of semi-finished lenses (blanks), each with its own base curve for a specific range of distance prescriptions.

To create the finished progressive lens, the optical lab selects the appropriate semi-finished blank for the distance Rx and add power, and the desired sphere and cylinder power are ground onto the back surface of the lens.

One drawback of conventional designs (for the optical lab at least) is the large number of semi-finished blanks that are required to service a full range of prescriptions. Also, when conventional progressive lenses are cut with conventional (non-digital) cutting tools, finished prescriptions that are near the upper and lower limit of the range for each base curve have aberrations that can be noticeable and bothersome for some wearers.

Free-form progressive designs: Free-form or digital progressive lenses are made with a computer-controlled, three-axis diamond cutting device that can apply virtually any curve to any point on the lens surface.

Free-form lens generators also are capable of a much higher level of precision than conventional generators: They can produce curves on a lens surface in 0.01 D increments, compared with 0.10 D steps produced by conventional tooling.

Also, the creation of free-form progressives eliminates polishing steps required when conventional tools are used, which improves the power accuracy and optical quality of free-form lenses.

The primary advantage of digital progressives for wearers is that free-form manufacturing technology can produce lenses with fewer peripheral aberrations than conventional progressive lenses made with conventional tools. The peripheral curves of free-form progressive lenses can also be adjusted ("optimized") to compensate for aberrations caused by the average frame fit.

An advantage of digital progressive lenses for optical labs is that a full range of prescriptions can be created with a much smaller inventory of semi-finished blanks. Also with free-form technology, the progressive power of the lenses can either be molded onto the front surface of a progressive semi-finished blank (like conventional progressives) or it can be cut onto the back surface of a single vision semi-finished blank.

Despite these benefits of free-form progressive lenses, it's important to know that digital progressives don't guarantee a greater wearer experience—patient satisfaction depends on the progressive design as well as (and perhaps more than) the method of lens fabrication.
Personalized digital progressive designs:
Personalized digital lenses take the customization (or optimization) of free-form progressive lenses to another level. With these lenses, in addition to the wearer's prescription and adjustments made for an average frame fit, the power of personalized digital progressive lenses is adjusted to take into account the actual frame the patient selects so it is tailored for the actual position of wear of the lenses and the size and shape of that particular frame.

Though personalized digital lenses feature impressive design technology, they also are the most expensive progressive lenses available, and they usually require specialized dispensing equipment and skills to prescribe and fit them.

And while some wearers will appreciate the added degree of customization that go into the fabrication and fitting of personalized progressive lenses, it remains somewhat unclear just how many presbyopes will find these lenses provide enough added clarity and comfort to make the extra cost of personalized digital lenses an unequivocal value.


CONVENTIONAL PROGRESSIVES STILL DOMINATE

So which type of progressive lenses are most popular?

Currently, less than 25 percent of progressive lenses sold in the U.S. are free-form lenses (including both optimized and per- sonalized digital progressives).

In a 2012 VisionWatch survey of eyecare professionals, though 84 percent of respondents reported that they offer free-form progressive lenses, more than three out of four of their patients purchased conventional progressive designs.

The largest number of progressive lenses sold—39 percent of the total—were classified as premium conventional progressive designs; 24 percent were standard conventional designs; 23 percent were free-form (digital) designs; and 14 percent were value conventional designs.

Though the survey did not identify reasons why free-form progressive lenses have not supplanted lenses with conventional progressive designs, one possible reason is the high degree of satisfaction that most presbyopes experience with conventional progressive lenses—especially those classified as premium conventional progressives. Wearer trials of the latest premium conventional progressive lenses reveal overall satisfaction ratings that exceed 90 percent.

And some premium conventional progressives such as Vision-Ease Lens' new Anthology progressives featured in this product spotlight are now incorporating elements of digital lens manufacturing that are elevating the optical performance of these lenses to levels comparable to free-form progressives... without the premium costs associated with full digital designs (especially when compared with the cost of personalized free-form lenses).

CHOOSING THE BEST GO-TO DESIGNS FOR YOUR DISPENSING TOOLBOX

Given the advances in progressive lens tech- nology and designs, the increased costs associated with free-form lenses and the current market statistics, which progressive lenses should be the go-to lenses in your dispensing toolbox?

The key to progressive lens success in today's marketplace is to develop a rational and effective approach to presenting progressives lenses that: 1. Feature advanced, high-performance designs that you can recommend with confidence. 2. Are most likely to delight your patients without breaking their budget, and 3. Produce happy patients that refer friends and family to your practice.

The new Anthology series of premium progressive lenses from Vision-Ease Lens were designed with these important goals in mind.

ANTHOLOGY PROGRESSIVES: GO-TO LENSES FOR TODAY'S DEMANDING PRESBYOPES

The Anthology series of premium progressive lenses features three specific designs to satisfy the unique needs of today's demanding pres- byopes:
Novel is a versatile, all-purpose progressive lens with a soft, balanced front-surface progressive design. Novel is designed for the broadest range of wearers, prescriptions and frame styles; and features a 13-mm progressive power corridor length and 16.5-mm fitting height.
Novella is a short-corridor version of Novel to accommodate smaller frames. With its compact 11-mm progressive corridor length and 14-mm fitting height, Novella affords presbyopes a much greater selection of smaller frame styles. And like Novel, Novella features a soft, balanced design for easy adaptation and wearer comfort.
Narrative is the most advanced Anthology progressive and features a customized, digital back-surface design for the most demanding presbyopes. The free-form, backside progressive design of Narrative provides all the benefits of Novel and Novella, and has even wider optical zones for all viewing distances.

Narrative is available in both 13-mm and 11-mm progressive corridors for optimum performance in a wide range of frame sizes, and can be further customized with position-of-wear measurements provided by the optician.

Anthology progressive lenses are available in a variety of lens materials, including lightweight and impact-resistant polycarbonate, plastic, Trivex and super-thin 1.70 Thindex high- index plastic.

For outdoor wear, Anthology progressives also are available in Vision-Ease Lens' Coppertone and SunRx polarized sun tints, and with photochromic treatments by Vision-Ease Lens (LifeRx /Change Rx) and Transitions Optical. (Availabilities vary depending on lens design.)

ADVANCED FEATURES OF ANTHOLOGY PROGRESSIVE LENSES

All progressive lenses in the Anthology series—Novel, Novella and Narrative—share common design and fabrication characteristics to optimize optical performance, comfort and wearer satisfaction.
Large viewing zones, soft and smooth design: Progressive eyeglass lenses have been commercially available for more than 50 years, and lens design expertise and technology have continually improved since the first progressive lenses were introduced in 1959.

Over the years, lens manufacturers have recognized three critical factors in producing premium progressive lenses that offer presbyopes clear, comfortable, functional vision at all distances: size of viewing zones, softness of design and smoothness of power transitions.
Size of viewing zones: To determine the required size of a comfortable distance viewing zone in a progressive lens, one has to consider the size of the fovea—the small area within the central retina (macula) that contains densely packed photoreceptors responsible for high-resolution vision (cones).

The fovea has a visual angle of about 10 degrees. When looking straight ahead, this translates to about a 7.5-mm zone on the lens. But since the eye rotates from side to side, the size of the clear zones in progressive lenses for tasks such as reading, computer use and driving must be made significantly larger.

If the maximum lateral eye movement is 15 degrees before a person turns their head when viewing distant objects, the functional viewing area of the distance zone of a progressive lens should be approximately 40 degrees—30 degrees plus 5 degrees to each side of the center of the fovea (assumes a 13-mm vertex distance).

The Novel progressive features a distance viewing zone with a functional design width of 43 degrees, allowing ample room for comfortable distance vision. This is especially important for nearsighted presbyopes who tend to be keenly aware of any compromises to their distance vision.

The intermediate and near zones of progressive lenses can be smaller and still provide comfortable viewing, since eyeglass wearers tend to rely more on head movements than large, excursive eye movements to see clearly when using a computer and reading, compared with viewing distant objects.

Novel provides a lateral intermediate viewing zone of 15 degrees and a near viewing zone of 18 degrees, which have been proven ample and comfortable by extensive wearer trials (more on that later).

Novella features intermediate and near viewing zones of 14 degrees and 20 degrees, respectively.

The intermediate and near viewing zones of Narrative backside digital progressives can provide even greater width, depending on the prescription and position of wear.
Softness of design: All progressive lenses introduce some aberrations and unwanted cylinder power lateral to the primary distance, intermediate and near viewing zones of the lenses. These aberrations are primary causes of adaptation issues, such as an unwanted feeling of movement (or "swim") in the wearer's peripheral vision.

Generally speaking, soft progressive lens designs—those where these aberrations are less pronounced and occur more gradually in the lens periphery—are more comfortable and easier to adapt to than "harder" designs where aberrations occur more abruptly at the lateral borders of the viewing zones. Also, vision tends to be less blurred and distorted when looking through the periphery of progressives with soft designs versus those with hard designs.

Novel, Novella and Narrative all were engineered to provide the softest progressive design possible, while maintaining large, distortion-free viewing zones for distance, intermediate and near.
Smoothness: The smoothness of a progressive design describes the rate of change of increasing add power from the top of the progressive corridor to the center of the reading zone. Shifting seamlessly from distance through mid-range to near requires a combination of smooth power changes and accurate placement of the entire progressive corridor (i.e., the degree of "inset" of the reading zone).

For the greatest comfort, clarity and binocularity, the wearer's eyes should remain well-centered within the progressive corridor when looking through the lower half of the lenses, and the design also should accommodate normal vertical head and eye movements wearers make when working at a computer or reading.

For reading, a downward gaze of approximately 30 degrees is most comfortable for most wearers. This translates to looking through a point on a progressive lens that is roughly 15 to 16 mm below fitting cross on the lenses (assuming normal posture and an average vertex distance and position of wear for the lenses).

But many presbyopes begin to read higher in the corridor, at a downward gaze of about 24 degrees (11 to 12 mm below the fitting cross). This is especially true for many computer users who desire the "top of the page" to be clearly visible.

Intermediate or mid-range viewing generally occurs at a downward gaze of about 18 degrees (8 to 9 mm below the fitting cross).

The designs of Novel, Novella and Narrative progressives incorporate these general guidelines for the smoothness of add power progression, combined with extensive wearer trials, to accomplish the goal of maximum comfort and wearability.

Also, for comfortable computer vision and reading, the intermediate and near viewing zones of progressive lenses must be in the right position for the eyes as they rotate down and in. The design of Novel, Novella and Narrative progressives includes a variable inset design to ensure the location and path of the progressive corridor is optimally aligned for all wearers, regardless of the prismatic effects of the distance prescription when the eyes converge for reading.

In other words, the reading area for a high- minus distance prescription has less inset than a plano distance lens, which has less inset than a plus distance power lens. This ensures that the reading area is right where it is needed, given the different prismatic effects of these lenses when the eyes are in a downward, converged position.

All this sounds great on paper, but how can you be sure Novel, Novella and Narrative are the type of go-to lenses that will fully satisfy the needs and demands of your real-life presbyopic patients?

The affirmative answer to that question (along with final optimization of the Novel, Novella and Narrative designs) came about by means of extensive wearer trials, according to Vision-Ease Lens.

DESIGNED FOR WEARERS...
BY WEARERS

To finalize the progressive designs of the Anthology series, designers conducted multiple field trials of Novel, Novella and Narrative lenses on large numbers of presbyopes with a wide variety of visual needs.

The goal of these trials was to refine the performance of each Anthology design and maximize wearer satisfaction for a very broad range of presbyopes with multiple and varied visual demands.

The term Vision-Ease Lens uses to describe this wearer "beta" testing and refinement of Anthology progressives is "iterative design" or "paper-people-paper." In other words, the lens designers set out to create the most comfortable, all-purpose progressive design mathematically, then evaluated the performance of the lenses with real-life wearer trials, then adjusted the design accordingly and retested it in the field.

This process was repeated until the desired outcome of an overall wearer satisfaction was attained, according to Vision-Ease Lens.

TOOLING AND FABRICATION PROCESSES

When it comes to modern progressive lens technology and fabrication, two statements are true:

  1. Advanced digital fabrication processes cannot salvage a weak progressive design, and
  2. A superior progressive design can be undermined by poor fabrication processes.

For optimal performance and comfort, a go-to progressive lens needs an excellent progressive design, but it also needs to be reliably and accurately produced with state-of-the-art tooling and fabrication processes.

To create the highest quality polycarbonate semi-finished blanks for Novel and Novella progressive lenses, Vision-Ease Lens uses advanced, diamond-turned metal tooling. Diamond-turned tooling is superior to other methods of creating traditional front-surface progressive lenses (e.g., stainless steel molds, glass molds, ceramic molds) because it produces exceptionally smooth and precise surfaces that require virtually no polishing and provide micron-level shape accuracy for optimum optical performance.

Diamond turning directly transfers XYZ data (mathematical points) into the mold, allowing for true progressive design replication accuracy.

Free-form 3D diamond tooling also is used in the Vision-Ease lens fabrication facility to accurately apply the distance prescription on the back surface of Novel and Novella progressives to a precision level of 0.01 D.

This advanced tooling also is used to apply both the distance power and the free-form progressive design on the back surface of Narrative all-digital progressive lenses.

FITTING EASE AND ACCURACY

Finally, let's not forget the hands-on dispensing skills of the optician when it comes to the performance of progressive lenses.

Even the best-designed, best-fabricated progressive lenses can produce poor outcomes if fitting measurements are inaccurate. An advantage of Novel, Novella and Narrative progressives is they don't require special fitting equipment or new, unfamiliar measurement techniques.

As with other conventional progressive lenses, the only required measurements are: prescription (including add power), monocular PDs and fitting height.

This is true even when fitting the all-digital back-surface Narrative progressive, which is already optimized for these average position-of-wear measurements: 13-mm vertex distance, 9 degrees pantoscopic tilt and 7 degrees face form angle.

However, if desired, Narrative lenses can be customized with actual position of wear measurements for vertex, tilt and wrap angle, taken by you with the dispensing tools and techniques of your choice.

The ease of fitting Anthology series of progressives is another advantage of making these lenses the go-to progressives in your toolbox, especially for offices with opticians who may not be skilled at position of wear measurements.

Ease of fitting also enhances efficiency, which can enable you to serve more customers during busy days.

USING YOUR NEW TOOLBOX

After adding the Anthology series of premium progressives to your dispensing toolbox, you're ready for action. Here are a few tips to help you use your new tools for greatest efficiency and patient satisfaction:

  1. Start by describing the benefits of an all-purpose progressive design for your customer's primary pair of glasses. Explain that while progressive lenses cannot reverse presbyopia, a well-designed, all-purpose progressive lens can satisfy most visual needs most of the time.
  2. Mention that two types of premium progressive lenses are available: conventional designs (Novel, Novella) and fully digital designs (Narrative). Describe how modern conventional designs offer comparable visual performance and comfort at a lower price, creating room in a person's budget for a second pair of glasses for specific needs (prescription sunglasses, computer glasses, sports glasses, etc.).
  3. Choose Novel or Novella lenses as the primary go-to lenses, unless the customer has special needs. Examples of special needs might include: A. A history of poor adaptation to multiple brands of premium conventional progressive lenses. B. A very strong prescription (plus or minus) or high cylinder, and C. A frame with unusual position-of-wear measurements due to facial size or shape. Recommend customized Narrative lenses as the primary go-to lenses in such cases.
  4. Offer the customer a satisfaction guarantee with their new Novel or Novella lenses, and tell them additional customization with Narrative lenses is available (at an additional cost) in the unlikely event they cannot adapt to the premium traditional progressive lenses.

CONCLUSION

With so many options available in progressive lenses these days, it's easy to become overloaded with information and confused about the best go-to progressives.

To reduce the stress of too many choices, consider cleaning out your dispensing tool-box and restocking it with a limited number of premium progressive lenses to make the lens selection process more enjoyable for both you and your customers.

Choose progressives with a modern conventional design as your primary go-to progressive lenses for at least 80 percent of presbyopes. For the best value for your patients, choose lenses with an all-purpose, wearer-tested design that are fabricated with advanced tooling and processing techniques. Modern conventional progressive lenses—such as Vision Ease Lens' Novel and Novella progressives—provide exceptional comfort and performance and can be positioned at a more affordable price point than fully digital designs.

Include at least one fully digital premium progressive lens in your toolbox for patients with special needs or who simply want the most advanced technology available, whatever the cost. A fully digital design also can be a good problem-solving option for patients who have been dissatisfied with more than one brand of premium conventional progressive lenses.

The new Anthology series of premium progressive lenses from Vision-Ease Lens that includes both conventional designs (Novel, Novella) and a customizable, fully digital design (Narrative) seems to be a good fit for the new go-to progressives in your dispensing toolbox.