Visual Fatigue Syndrome Solutions
The Shifting Demand for Comfortable Mid-Range Vision
| November, 2009
| December 31, 2010
Upon completion of this program, the
participant should be able to:
- Understand the symptoms and causes of Visual Fatigue Syndrome (VFS)
- Learn methods that relieve the symptoms of VFS
- Know the performance characteristics and use of two new lenses designed to address VFS.
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.
This course is approved for one (1) hour of CE credit by the American Board of Opticianry (ABO).
|This 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 DISPLAY
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)
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.
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 Lenses—Less 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
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.
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
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
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.
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
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