View Test
 

Visual Fatigue Syndrome Solutions
The Shifting Demand for Comfortable Mid-Range Vision

By Pete Hanlin, ABOM, Essilor of America

Release Date:

November, 2009

Expiration Date:

December 31, 2010

Learning Objectives:

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

  1. Understand the symptoms and causes of Visual Fatigue Syndrome (VFS)
  2. Learn methods that relieve the symptoms of VFS
  3. Know the performance characteristics and use of two new lenses designed to address VFS.

Faculty/Editorial Board:

author

Pete Hanlin is employed by Essilor of America as manager of training & development. Hanlin’s experience includes management of private practices, retail dispensaries and ophthalmic laboratory operations. As an ABO/NCLE approved speaker he has presented CE hours to numerous state and national associations. Hanlin is certified by the ABO/NCLE as a Master Optician and is a licensed dispensing optician in the state of Florida.

Credit Statement:

This course is approved for one (1) hour of CE credit by the American Board of Opticianry (ABO).
Course STWJMI122-1

logoThis course is supported by an educational grant from Essilor

There has been a dramatic—and undeniable—shift in the visual demands placed on the average person over the past few decades. When PALs were introduced to the U.S. market in the early 1970s, the most visually demanding tasks faced by the average presbyope involved manual typewriters, rotary phone dials and the wide pages of the daily newspaper. Today, life for the modern presbyope is a visual obstacle course composed of texting, tiny digital camera screens and those ridiculously miniscule cell phone displays and keypads.

Basically, many presbyopes now live a large portion of their vocational life in a “visual box” that extends two to six feet in front of their eyes—and it’s time eyecare practitioners came to the realization that traditional PALs are not designed for this world.

THE UBIQUITOUS COMPUTER DISPLAYfig1

Between work, home, shopping and school, the average patient encounters computerized displays in one form or another almost constantly. In fact, the U.S. Bureau of Labor Statistics reports that 100 million people in the U.S. spend over 50 percent of their workday at a computer. These displays take many forms and each has its own characteristics and concerns (just take a moment to consider the difference in screen sizes and viewing distances for PDAs, cell phones, DVD players, laptops or desktop displays). Even similar displays are encountered differently depending upon age and ametropia. A 13 year old who has a small amount of uncorrected hyperopia may experience a headache after eight hours of Twittering— but 30 minutes of texting may leave a 60 year old with a sore neck from the awkward position required by bifocals and even PALs.

Software and hardware manufacturers have spent significant time developing easily seen screens and easily read fonts and displays. Ophthalmic lens manufacturers have developed numerous products designed to improve the visual perception of computer screens. However, the ophthalmic community has for the most part failed to embrace these products—leaving millions of American eyewear consumers to fend for themselves with over the counter readers (or worse, a simple resignation to accept headaches and neck pain as a “fact of modern life”).

THE PROBLEMS ARE THREEFOLD

In a recent survey conducted by VisionWatch, (consumer-based eyewear market research by Jobson Research/Vision Council), consumers were asked: “Do you currently use glasses that are specifically worn when using a computer?” Only 5 percent (11.3 million people) responded yes.

In fact, there are about 100 million presbyopes wearing prescription multifocals in the U.S.—with an average ADD of +2.25. Obviously, patients underestimate both their exposure to computer displays and the function their eyewear plays in performing near activities. This reminds me of a pre-exam encounter with a patient some years ago. When I asked if she “regularly engaged in near vision tasks,” she responded “not really.” Noticing she worked at the DMV, I inquired about her job there. “Oh, I process license applications on a computer pretty much all day.” Hmmmmm...

Okay, so we know there are millions of patients using—and struggling—with computer monitors every day. Yet relatively few computer specific lenses are dispensed.

What gives? There are three problems, which have hampered the widespread use of computer spectacles. First, patients obviously may not realize how much of their day is spent doing near vision tasks. Second, many patients fail to associate the physical effects of Visual Fatigue Syndrome (primarily tired eyes, neck pain and headaches) to their eyewear correction (many consider the cause of their symptoms to be stress-related). Finally, practitioners have been confused by the variety of near variable focus products.

The Details of Visual Fatigue—Visual fatigue is a combination of factors; environmental, physiological and activity related. The environment includes lighting, stress, air conditioning, screen location, chair, multiple computer screens, screen location or any combination. Remember, screen-positioning issues affect final lens positioning.

Physiological issues result in tired eyes (asthenopia). Activity related symptoms are pain, eyestrain, tiredness and headaches. Strain is created when there is prolonged or intense intermediate and near vision activities, like working on a computer, reading or hobbies. A computer screen or gaming console can stress both the accommodation and convergence. This results in fatigue or difficulty focusing clearly and quickly at various distances.fig2-4

Symptoms and Patients—Everyone in the digital community is affected regardless of myopic, hyperopic or astigmatic prescriptions. Even the emmetrope suffers. It is also true of the non-presbyopes as well as presbyopes—although the presbyope requires special consideration.

So, for spectacle and contact lens wearers, recognizing symptoms and creating the right solution is key. Remember, the +2.25 add bifocal wearer has none of the lens power required to focus at intermediate distance. Contact lens wearers may be using over-the-counter readers but they’re only good for either near or intermediate. If fit with monovision, intermediate may be too difficult to sustain. Refractive surgery and presbyopic patients may be corrected for monovision, also with the same issues. If presbyopic, they may not understand that they still need glasses for reading and for mid-range.

Explaining why is part of the solution. It connects the symptoms with the lenses needed for easy computer viewing.

The Problem With Today’s LensesLess than 5 percent of Americans today wear eyeglasses to relieve vision problems at a computer, despite significant regular computer use by over 75 percent of the population (source VisionWatch). “Computer” lenses have been on the market for more than 15 years yet they have only achieved limited success.

The vast majority of the computer using population is simply not aware of possible solutions and therefore not receiving appropriate diagnosis and treatment. In addition, the lenses available may require a power conversion before the lab can process them. Errors happen when the ECP or the lab assumes conversion by the other. Powers are incorrect, costs are incurred for redo’s and the patient has to wait for the remake.

Near Variable Focus lenses are progressives that are reading lenses with a reduction of power from bottom to top called a degression or range. The correct power patients’ need is located vertically along the path of the progression. However, these zones can be as long as 28mm or as short as 10mm so knowledge of the patient’s need and the lens design available is required for best prescribing/dispensing.

The final location of the ideal power, vertically in the frame, is a critical factor in reducing excessive head rotation. Ideally, the required mid-range power should be located at the right vertical fitting point so that the head and body posture allows a comfortable position for all the time required in front of the screen.

One major computer manufacturer’s ergonomic department has labeled the classic head up/hunched forward posture as “turtling.” (Think of the shape of the shell of a turtle and its head extended up unnaturally.) How can these issues be fixed?

NEW LENSES FOR THE PRESBYOPE AND PRE-PRESBYOPE

A new lens category is appropriate to address the causes of general visual fatigue but the needs are different by age group and the stage of presbyopia. This suggests two large patient categories, the “non” or “emerging presbyopes.” The other is the more “mature presbyope.”

Design solutions are based on Essilor’s research of the causes and the treatments that are most effective. Understanding symptoms and clinical cause-based characteristics for wearers for a variety of tasks allows the development of different design solutions. The result was a portfolio of lenses to treat each of the symptoms effectively. Then, reduce the number of designs to the most common forms that addressed the most issues concurrently. Finally, launch a series of test markets to test lens options and messaging. This resulted in two new lenses for a digital world suffering from visual fatigue.

ESSILOR ANTI-FATIGUE

Technology—This single-vision lens has a + 0.6D “power boost” in the lower portion of lens and is designed for non-presbyopes and emerging presbyopes, whether plano or prescription. Therefore, this lens can be prescribed as a primary pair of lenses (for students, office workers) or as a task-specific second pair.

The power boost relieves the demand for convergence and accommodation by delivering additional power 10mm below the fitting point. This naturally matches a single-vision wearer’s needs using normal posture for reading. It can make a full day’s reading or close work easier and more comfortable.

Fitting and Ordering—Fitting and mounting these lenses is simple. Lenses are fit at pupil center, a way familiar to opticians and doctors. To ensure that there is enough area for the full power boost, fit at a 13mm minimum fitting height and a 23mm minimum B measurement. Order lenses using monocular distance PDs and specify monocular fitting heights.

Material and Treatments—The Rx range includes a variety of materials for Rx versatility, thinness and lightness as required by any patient. They are 1.67 and polycarbonate (-10.00 to +6.00, cyls to -4) and 1.50 index (-6.00 to +6.00, cyls to -4). All materials systematically include anti-reflective coatings that complement lenses designed to reduce visual fatigue.

Key Patient Targets—Typically 35 to 45 year olds, those that are just starting to need slight plus for reading, emerging presbyopes, are key patients to target. These patients aren’t yet ready for a full progressive lens. Myopes can also benefit, those aged 18 to 34 years that complain of tired eyes or other symptoms associated with visual fatigue.

But, what about the true presbyopes in your practice; those with adds of +1.75 and more? They suffer from little or no accommodative effort available, especially at mid-range.

PROBLEMS WITH PROGRESSIVES

When a mature presbyope has only one pair of progressives and uses them for all tasks, they rely on the physical characteristics of the intermediate for mid-range work. A general-purpose progressive has a narrower intermediate than near or distance so many wearers find a limited field-of-view. Moreover, this is bordered by distortion and blur so the increased need for head movement can make sustained use uncomfortable or difficult. This results in a lot of nose pointing and turtling since the powers needed are not located in the right place for comfortable viewing.

Current computer progressives have been a good solution because they limit the progression or power change and the result is larger viewing zones. By reducing the power change and zone size, the intermediate and near will be larger and bordered by less blur and distortion. However, computer users can benefit from having some true distance vision. Historically, AO Technica and now a number of other lenses can be ordered for ranges from true distance to near. Depending on the way that the degression is chosen and positioned, computer lenses can be ordered for the range of vision required.

However, the dispenser must understand the design of each lens to be able to predict where needed powers are located. Also, different lenses have varied progression lengths placing the right power perhaps at the wrong height.

Some computer lenses require conversion to a “total near power” for processing in the laboratory; the lab converts others. This has been a source of much confusion and often the lab and ECP both convert the Rx, creating too much plus power, an incorrect solution and therefore a redo.

NEW ESSILOR COMPUTER LENS

Keeping the issues of current progressives and computer progressives in mind, a new lens for computer users was developed. The Essilor Computer Lens provides a wide clear intermediate area to see the entire screen or other intermediate object. With a wide near area and a small clear true distance, the lens allows the wearer to also to see from close up to across the office or room. With a unique plateau of 60 percent of add power located at the fitting cross, the fitting process ensures that the right power is at the right location. This reduces the need for unnatural head tipping.

Technology—Figure 6 describes the relative zone sizes of Essilor Computer. Note that a small distance zone is provided at the top of the progression. In Figure 7, the three power plateaus show distance, 60 percent add and full add power. This uniquely allows for wide and clear, intermediate and near viewing in a lens that includes a small distance field for looking across the room or completing office errands comfortably.

Fitting and Ordering—Lenses are ordered like a typical progressive; the lab does the conversion. Lab software will convert the Rx and select the correct add power from one of the four add powers available (+1.00, +1.50, +2.00, +2.50D). This ensures that 60 percent of the reading power is delivered at the fitting cross by design. Specify monocular distance PDs. Fit with a 15mm minimum segment height, and to ensure the patient reaches the area of full distance, fit with 15mm above the fitting cross as well. Rx Range: -6.00 to +7.00D, cyls to -4.00.

Material and Treatments—The lens is available in polycarbonate for thinness and lightness to ensure comfort. Be sure to always include AR. AR reduces screen and surrounding glare while it improves image clarity. These lenses are approved for all premium and value AR coatings.

Key Patient Targets—Those diagnosed with Visual Fatigue Syndrome i.e., symptoms that are activity-based are prime candidates. Consider using a questionnaire and/or the patient history form to discuss symptoms and solutions with the patient. When there is a diagnosis of accommodative problems, vergence or other issues, this lens is indicated. Determine the best treatment and use the most appropriate lens design, either as an all-day first pair (SV antifatigue) or a task-specific second pair (computer progressive).

Screening for Visual Fatigue Patients—Ask every patient: “Do you ever have tired eyes, headaches, blurred vision or neck and shoulder pain at the end of the day?” If yes, alert the doctor, note it in the chart and be sure that the optician knows.

TEST RESULTS

Two groups of wearers were asked to test this new lens; those satisfied (n=33) with their current vision at the computer and a group dissatisfied (n=30). In both cases, this new lens produced improvement in all six areas. As might be expected, those not satisfied with their current lenses had the best results, but even those satisfied showed significant improvement. The following graphs show preference for the Essilor Computer Lens when compared to their current PAL or vision.
1) Source: Essilor International – EC Lens Wearing Trial - October ’05 (89 subjects ages 40+) UK, France

fig8CONCLUSION

Considering the fundamental shift in the demand for intermediate and near vision in today’s world of electronic communication, the right lenses are essential for comfort and productivity. These two new products, Essilor Anti-Fatigue and Essilor Computer Lens are correctly named. Together they solve a prime need for today’s patients of all ages.

Good intermediate and near vision care is now much simpler. Fill this unmet visual need for your patients and they will thank you for it. They depend on you to provide the best of care—it’s a key practice builder.