Download View PDF with Images - Advanced Ocular Care

OPTICAL TECHNOLOGY
Enhanced Multifocal
Lenses Represent a
New Category
PixelOptics’ patented composite lens technology reportedly provides clear, continuous vision.
BY D. PENN MOODY, OD
L
egend has it that none other than Benjamin
Franklin deserves credit for the invention of what
we now know as bifocal lenses. Yet, many historians insist that Mr. Franklin’s opticians in both
London and Paris already had some knowledge of such a
lens before America’s elder statesman came to seek them.
Historians may quibble over the origins of split-lens bifocals, but one thing remains clear: for millions of patients
around the world, the bifocal lens has offered a practical
solution to their particular presbyopic condition. Specifically, each year, more than 17 million pairs of bifocals
are dispensed to patients in the United States alone.1
DRAWBACKS OF BIFOCAL LENSES
Despite their widespread use and effectiveness, bifocal
lenses are not without their drawbacks. For many people,
the traditional flat-top bifocal lacks the aesthetic appeal
that they seek. Other wearers are frustrated every day by
“power jumps,” a jarring and unsettling change in focus
brought about by the proximity of vastly different segments of the lens. The thick-segment ledge of the typical
flat-top often creates a visual distraction, primarily due to
reflections. One shortcoming of the traditional bifocal lens
has become increasingly important in today’s complex
visual environment—poor performance at intermediate
distances.
Several factors create both a challenge and an opportunity for today’s savvy eye care provider. First, because
two-thirds of bifocal wearers are older than 55, an age
when accommodation is almost entirely lost, the average
add power is now close to +2.50 D. That means the
majority of wearers have adds greater than +1.75 D, a
power at which intermediate clarity is significantly
reduced. For most people, the depth of focus through
58 ADVANCED OCULAR CARE MARCH 2010
the segment is only about 14 to 18 inches. This becomes
very noticeable when the object is between 18 and
30 inches away. Because many tasks are performed in this
range, lack of clarity can be very frustrating.
If the expression “50 is the new 40” is true, then intermediate is the new near when it comes to visual demand.
When one considers which activities in daily life demand
accurate vision, one can begin to understand the difficulties faced by today’s presbyope, whether still in the workplace or retired. One of the most common challenges for
this group involves achieving accurate vision when viewing computer monitors, particularly laptop monitors,
which are typically located 18 to 22 inches from the eye.
Consequently, everyday tasks such as checking e-mail or
looking up information on the Internet pose significant
challenges for many of these patients. Other common
visual tasks with intermediate demand are viewing items
on a shelf at the store, playing cards, eating at a table,
working a TV remote, and operating kitchen appliances.
Nearly all of a person’s common visual demands are primarily at an intermediate distance.
Today’s progressive lenses have come a long way
toward addressing some of these issues. For a variety of
reasons, however, a vast number of bifocal wearers simply
cannot or will not make the switch. Some may prefer the
larger reading area of bifocals, some may believe the difference in progressives to be purely cosmetic, and some may
have simply been wearing bifocals for so long that they—
or their eye care professional—are reluctant to make the
change.
Whatever the reasons for rejecting progressives, it is certain that millions of bifocal wearers could benefit from a
new kind of lens, one that provides an extended range and
width of intermediate vision combined with a significant
OPTICAL TECHNOLOGY
jump (at 70% less than a bifocal of equivalent add
power) when transitioning between distance and
far-intermediate vision.
HOW IT WORKS
In atLast! enhanced multifocal lenses, the rear
component has a round segment with a single,
fixed power. The Trivex front component includes
a progressive that contributes the rest of the add
Figure 1. The Trivex front component includes a progressive that conpower (Figure 1). The embedded segment is invistributes the rest of the add power.
ible when viewed from the front.
The lenses provide four zones of vision (Figure
2). Above the segment line is a distinct zone for
distance vision, much like the area above a bifocal
segment. This zone extends all the way across the
top and down the sides of the segment to provide crystal clear distance vision with no peripheral aberrations. The other three zones are continuous. As the eye focuses below the embedded segment border, it encounters the power of the segment itself, which is less than one-third of the prescribed add. This technology provides farintermediate clarity at distances beyond arm’s
reach, out to about 5 feet. The progressive starts
below the segment line to provide intermediate
vision and continues to increase to a point just
Figure 2. The lenses provide four zones of vision.
above the segment’s center, where it reaches full
add power for near vision correction. The results
reduction in power jump while retaining some of the
are large, clear areas of vision with a small power jump at a
familiar characteristics of bifocals.
soft-line discontinuity.
It is no secret that, in many practices, bifocal wearers
ENHANCED MULTIFOCALS
have long been considered a price-sensitive commodity
PixelOptics (Roanoke, VA), using advanced composite
market sector, perhaps for good reason. Given the limitatechnology, has created AtLast! specifically to address inter- tions in performance of the traditional flat-top bifocal and
mediate visual demands. Part of a new category of lenses
the seeming reluctance of the market to use progressive
called enhanced multifocals, AtLast! has several distinct
lenses, these buyers have come to expect to pay less and
advantages over traditional lined and progressive lenses:
get less. The advanced performance offered by the atLast!
• It has the widest clear intermediate area of any lens on
Enhanced Multifocal Lens provides wearers with a far highthe market.
er level of performance at all distances, particularly in the
• It eliminates the troublesome peripheral aberrations
intermediate ranges. The technology also offers optical
common with progressives.
retailers an opportunity to move this market sector to
• It has a “soft jump” when going from distance to
intermediate or premium price points. ■
intermediate.
D. Penn Moody, OD, founder of Moody Eyes in
• It has a composite design that makes the lens thinner
Indianapolis, has been in practice for more than
and lighter than most comparable lenses.
30 years. Although he does not have a financial
• It offers a “no-line” cosmetic appearance.
The design increases the wearer’s range of near and inter- interest in the product mentioned herein, he does
mediate vision by more than 10 times that of a bifocal. This on occasion speak on behalf of PixelOptics on a
contractual basis. Dr. Moody may be reached at
is accomplished by adding a progressive surface to the
(317) 883-1122; [email protected].
front of the lens and embedding a power segment within
the lens. This design provides the wearer with continuous
1. VisionWatch.The Vision Council Lens Index Report.March 2008.
http://www.jobsonresearch.com/Scripts/prodList.asp?idCategory=15.Accessed February 18,2010.
wide vision from close up to 5 feet away, with a soft power
MARCH 2010 ADVANCED OCULAR CARE 59