PDF Edition - Review of Optometry

Transcription

RCCL
SEPTEMBER 2015
SPECIAL ISSUE:
CUSTOM LENSES
REVIEW OF CORNEA
& CONTACT LENSES
Gas Permeables
Are You Making Good
Use of Your Diagnostic
Fitting Sets?
One Size Does
Not Fit All
Making the Case
for Custom Lenses
Custom Contact
Lenses in 2015
Options Abound!
to Improve Scleral Lens Fitting
Supplement to
001_RCCL0915_cover.indd 1
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1
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8/25/15 12:47 PM
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RCCL0915_Alden.indd 1
8/19/15 10:25 AM
contents
Review of Cornea & Contact Lenses | September 2015
departments
4
News Review
CDC Report Notes Widespread
Lens Care Noncompliance
6
My Perspective
The Myopia Menace
By Joseph P. Shovlin, OD
8
Pharma Science & Practice
Pregnant Pause
By Elyse L. Chaglasian, OD, and
Tammy Than, MS, OD
10
Practice Progress
Meet the Candidates
By Mile Brujic, OD, and
Jason R. Miller, OD, MBA
32
The GP Expert
A Lens for Every Eye:
Custom Contact Lenses
By Stephanie L. Woo, OD
34
Out of the Box
Blinded by the Light?
By Gary Gerber, OD
features
12
16
22
26
Making the Case
for Custom Lenses
Finding a lens for every patient can boost
your practice and your profits.
By Robert Ensley, OD
GPs: Are You Making Good Use
of Diagnostic Fitting Sets?
An expert walks you through the finer points
of the process to help you achieve better
results.
By Joel A. Silbert, OD, FAAO
Options Abound:
A 2015 Report on Custom
Contact Lenses
Keep abreast of new lens developments and
related technology that can strengthen your
practice.
By Edward S. Bennett, OD
features
CE — Critical Measurements
to Improve Scleral Lens Fitting
Gathering as much data as possible can help streamline
the process and provide better outcomes.
By Jason Jedlicka, OD
Cover design by Matt Egger
©iStock.com/Jobsonhealthcare
/ReviewofCorneaAndContactLenses
003_RCCL0915_TOC.indd 3
#rcclmag
REVIEW OF CORNEA & CONTACT LENSES | SEPTEMBER 2015
3
8/25/15 10:23 AM
News Review
CDC Report Notes Widespread
Lens Care Noncompliance
O
ne in six US adults wears
contact lenses, and virtually
all engage in some form of
risky behavior concerning lens care.
Those are a few highlights of a new
report from the US Centers for Disease Control (CDC) on contact lens
wearer demographics and behavioral
influences on risk of contact lensrelated eye infection, part of the organization’s Morbidity and Mortality
Weekly Report.1
The population-based study identified 40.9 million contact lens wearers
(i.e., one sixth of the adult population) in the country, with 93%
wearing soft contact lenses. Of the
total respondents, most were white
(64.5%) females (60.7%) aged 3039 (24.8%) from the South (37.1%)
with a high school level of education
(31.5%) who live in metropolitan
areas (87.1%). The study did not
consider lens wearers under age 18.
A subset of the contact lenswearing population (n=1,000) also
completed the CDC’s Contact Lens
Risk Survey. Roughly 99% of the
respondents reported at least one
contact lens hygiene risk behavior
associated with an increased risk for
eye infection or inflammation. These
include:
• Exposing lenses to potential
water-borne contamination, either
by swimming (61%), showering
(84.9%) or rinsing them in tap water
(35.5%).
• Sleeping (50.2%) or napping
(87.1%) in their contact lenses.
• Topping off disinfecting solution
in lens cases rather than using new
solution (55.1%).
• Not complying with lens
(49.9%) or lens case (82.3%) replacement schedules.
“This population-based study admirably highlights the importance of
proper lens hygiene,” says Joseph P.
Shovlin, OD, a member of the CDC’s
advisory panel. “There are many
steps to compliance in caring for
lenses; unfortunately, risky behavior
remains a major risk for potentially
sight-threatening experiences.”
The organization also undertook
its second annual Contact Lens
Health Week in late August to address these deficits in public knowledge of lens care. “The Contact Lens
Health Week will help deliver the
much-needed reminder to lens wearers that contact lenses are a medical
device,” Dr. Shovlin says. “The message will undoubtedly help promote
safe and effective lens wear.”
1. Cope JR, MD, Collier SA, Rao MM, et al. Contact
lens wearer demographics and risk behaviors for
contact lens-related eye Infections — United States,
2014. MMWR, Vol. 64(32):865-70. Aug. 21, 2015.
Study Links CL Wear with Increased MGD Risk
Contact lens wearers, especially those who have worn lenses long-term, may be at
increased risk for meibomian gland dysfunction (MGD), reports a study in the September
2015 Cornea. Researchers evaluated the meibomian gland health of 41 daily soft lens
wearers vs. 31 age-matched non-lens wearers, using measurements of meibum expressivity and lid margin abnormality. Ultimately, the study conceded an incomplete understanding of the causative nature of the relationship, but found that contact lens use is responsible for early MGD and that wearers often do not exhibit symptoms severe enough
to warrant a typical clinical exam. They hope that more routine examinations of lens
wearers can reveal signs of MGD, which can be resolved using prophylactic modalities.
1. Machalińska A, Zakrzewska A, Adamek B, et al. Comparison of morphological and functional meibomian gland
characteristics between daily contact lens wearers and nonwearers. Cornea. 2015 Sep;34(9):1098-104.
4
IN BRIEF
• Certain cosmetic products may have
a significant adverse effect on contact
lens shape, wettability and optical
performance, report studies published
in the July 2015 Eye & Contact Lens.1,2
Researchers in Canada coated seven
silicone hydrogel lens materials with
nine marketed brands of cosmetics:
three hand creams, three eye makeup
removers and three mascaras.
Makeup removers were found to
have the greatest impact on lens
diameter, sagittal depth and base curve,
while mascaras were most detrimental
to optical performance and wettability.
The researchers note that in some cases
the effects were irreversible despite lens
cleaning, and suggest further clinical
studies are needed on the impact of
cosmetics on silicone hydrogel lenses.
1. Luensmann D, Yu Mili, Yang J, et al. Impact of
cosmetics on the physical dimension and optical
performance of silicone hydrogel contact lenses.
Eye & Contact Lens. 2015 Jul;41(4):218-227.
2. Srinivasan S, Otchere H, Yu Mili, et al. Impact
of cosmetics on the surface properties of silicone
hydrogel contact lenses. Eye & Contact Lens. 2015
Jul;41(4):228-235.
• Patients with good unilateral visual
acuity may be better candidates for a
Boston keratoprosthesis (BKPro) implant than previously believed, reports
a study in the September 2015 Cornea.1
Previously, implantation was only considered for patients with severe bilateral
visual impairment, due to long-term risk
and low expectations.
In a retrospective analysis of 37
BKPro patients (28 for failed PK, nine
primary BKPro implants) with pre-op
BCVA of 20/40 or better and mean
follow-up of 31.7 months, the most
common complications were elevated
IOP and retroprosthetic membrane
formation. Ultimately, the researchers
reported, half of patients achieved the
minimum VA required for binocular
functioning, with one-third achieving BCVA similar to the contralateral
healthy eye.
1. Mustafa K, Kunal S, Rapuano J, et al. Long-term
results of the boston keratoprosthesis for unilateral corneal disease. Cornea. 2015 Sep;34(9):10571062.
Advertiser Index
Alden Optical ............................ Cover 2
Bausch + Lomb...................... Page 5, 21
CooperVision ................Page 7, Cover 3
Hydrogel Vision......................... Page 19
Menicon ...................................... Cover 4
004_rccl0915_news.indd 4
8/25/15 12:48 PM
Go Ahead—Rock the Boat!
Steering a course toward technology and comfort with the
Bausch + Lomb ULTRA® contact lens
By
Andrew Paik, OD
Target Optical
Chicago, Illinois
One trend in the industry over the last
several years has been a shift toward daily
disposable lenses. In my own practice,
we typically recommended daily disposable lenses to most of our contact lens
patients, including patients who were
non-compliant in bi-monthly modalities.
In the past, for patients who were happy
in their current monthly lenses, we would
try to keep them in those lenses or else
recommend a daily disposable. All of that
changed with introduction of the
Bausch + Lomb ULTRA® contact lens,
which really has all of the features that
we’re looking for in a single lens – aspheric optics, high dk/t, low modulus, and
high moisture content. Together these
features mean a lens with great comfort
and performance that we now offer confidently to all of our monthly as well as
bi-monthly replacement lens patients.
Along with a shift in strategy in the
contact lens modalities I recommend has
also come a change in the focus of the
questions I typically ask my patients. Before, much of the conversation focused on
compliance. Now, in talking to patients,
I ask more specific questions about their
contact lens wearing experience. How
comfortable do your contacts feel at the
end of the day? How do your contacts feel
when you’re at your computer? If there’s
anything about your contact lenses you’d
like to change, what would it be?
Many patients have been wearing the
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same lens for many years so this is a good
way to at least get them thinking about
something new. Patients respond well to
this kind of questioning – they appreciate
that the doctor is taking an interest in the
quality of their contact lens wear.
One patient who comes to mind is a
38-year-old returning patient, who had
been wearing the same soft contact lens
for almost 8 years; about a year and a half
ago we had fit her into a new monthly
replacement lens that she didn’t like and
had gone back to her previous bi-monthly
lens. At this point she was really skeptical
about trying anything new but I persuaded her to try the Bausch + Lomb ULTRA®
lens. I expected that she would want to
Bausch + Lomb ULTRA is a trademark of Bausch & Lomb Incorporated or its
affiliates. All other brand/product names are trademarks of their respective owners.
US/ZUS/15/0160
RCCL0915_BL Ultra.indd 1
wear the trial lenses for a week or two
but instead she put the lenses on, walked
around the store looking at sunglasses,
and came back after 10 minutes and said
“These lenses are amazing!” and ordered
a year’s supply. On subsequent follow-up
two weeks later, the patient was extremely
happy with the lenses, reporting better
end-of-day comfort and less dryness.
Our office prides itself in having the latest
in technology – EMR, automated phoropters, retinal cameras – which show patients that we’re innovative and up to date
in terms of new technology. It’s something of a let-down after all that to leave
with the same contact lens prescription
the patient has been wearing for years.
Being able to offer patients an innovative
product like the Bausch + Lomb ULTRA®
lens that sets a high standard for comfort
and performance is a much more positive
experience, one that’s in line with the image we’re trying to present in the office as
a team. It’s helping to advertise that we’re
about change and improvement.
NRMANCE
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I
F
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ER
V
P
OT•
CO IN
MF N
OR
I
n fitting contact lens patients, it’s easy
to fall into the habit of “not rocking
the boat.” If a patient is happy in their
contact lenses, it often seems expeditious
just to leave them in a lens that they already like, without necessarily doing too
much critical thinking. By doing this, are
we missing an opportunity to offer our
patients the latest in contact lens technology, which is a focus for many of us in
clinical practice?
SPONSORED B
BY
Y B A U S C H + LO M B
8/20/15 1:44 PM
My Perspective
By Joseph P. Shovlin, OD
The Myopia Menace
The recent passing of Professor Brien Holden highlights the continuing need for
myopia research and clinical intervention, especially with contact lenses.
O
ver the past few
decades, the prevalence of myopia has
increased exponentially.1,2 In many
populations—especially Asian
cohorts—the morbidity associated
with myopic progression can be
devastating. Significant elongation
of the eye often results in poor
uncorrected acuity. Nearly as important, myopia is associated with
increased risks for glaucoma, cataracts, peripheral retinal pathology
(i.e., holes, tears and detachments)
and myopic macular disease.
Ongoing research is evaluating
several modalities to slow the rate
of myopia. These include pharmaceutical intervention with antimuscarinics (low-dose atropine and
pirenzepine gel), orthokeratology
(ortho-K) and multifocal spectacles
and contact lenses. Clinical trials
of ortho-K have demonstrated that
progression is slowed by about
40%.1-3 Soft multifocal contact
lens designs have demonstrated
similar results: by reducing near
eso fixation disparity, bifocal
contact lenses may improve near
vision comfort and reduce accommodation lag.1 A certain degree of
protection seems to be afforded
by peripheral myopic defocus lens
designs.
PROFESSOR BRIEN
HOLDEN: IN MEMORIAM
Initially, I was planning to highlight Brien Holden’s fabulous work
on myopia this month; I never
expected to provide a memoriam
honoring his memory. At this year’s
British Contact Lens Association
6
(BCLA) meeting, Professor Holden
presented a marvelous review of
(1) what should concern us with
myopic progression, (2) what we
have learned to date and (3) how
we might slow its progression.
Key points raised in his BCLA
presentation include: (1) outdoor
activities are essential to delay the
onset and perhaps even reduce
the rate of progression, (2) most
soft lens designs actually promote
myopia because of their negative
spherical aberration in peripheral
optics, (3) the recognition that
ortho-K actually works and (4) the
fact that peripheral plus (multifocal) lenses also work. Professor
Holden envisioned a day when a
stepped anti-myopia and extended
depth-of-focus lens would be custom designed for each patient with
more than 0.50D of myopia.
So, is the time to act now, as
Professor Holden believed? If your
comfort level is adequate using
lenses for a non-FDA approved
indication, perhaps it is good to
discuss contact lens options with
parents whose children are showing myopic progression. Also,
low-dose atropine (0.02%) may
be a viable alternative for any
patient unable or unwilling to
wear either ortho-K or multifocal lenses. However, research has
shown slower myopia progression,
but not slowing of eye growth, so
the mechanism of myopia control
remains a mystery.
Ortho-K and multifocal contact
lenses appear to have significant
benefits when fitted early in myopic
patients. Thus, we call upon manufacturers to seek approval for novel
designs, as in a stepped anti-myopia and extended depth of focus
lens approach. In the meantime, I
urge you to consider the exciting
treatment modalities available to
us today after careful and adequate
education of parents and individuals who may benefit most when using these lenses. Professor Holden’s
positive and lasting impact will
most definitely live on.
RCCL
1. Anderson RL, Aller T, Walline JJ. COntrolling
myopia, changing lives. Review of Cornea and
Contact Lenses. 2014(9):24-29.
2. Kading D, Mayberry A. Slowing myopia
progression in children. Review of Optometry.
2012(11):28-34.
3. Cho P, Cheung SW. Retardation of Myopia
in Orthokeratology (ROMIO) study: a two-year
randomized clinical trial. Invest Ophthalmol Vis.
Sci. 2012. 53(11):7077-85.
The Giant Among Giants
The eye world lost an amazing
individual in July. His resume
reads like a novel: 275 refereed
scientific articles, more than
450 abstracts and more than
125 keynote addresses. Over a
career that spanned more than
four decades, Professor Holden
received 30 international awards
from diverse organizations
around the world for his endless
contributions to research, clinical
science, public health and philanthropy. He served as a mentor
to so many of us and we’ll certainly have a story or two to tell
about how he enjoyed life.
What many of our readers
may not know is that Brien
Holden’s PhD thesis was on the
development and control of
myopia, a passion he pursued
tenaciously right up until his
death. Professor Holden holds 10
patents with an additional nine
pending, many of them related
to slowing myopic progression.
006_RCCL0915_MP.indd 6
8/25/15 10:26 AM
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RO0215_Coopervision Biofinity.indd 1
1/20/15 3:42 PM
Pharma Science & Practice
By Elyse L. Chaglasian, OD, and Tammy Than, MS, OD
Pregnant Pause
Updates to the FDA’s pregnancy drug categorization system mean changes for your
practice. What should you expect?
A
patient presents to
your office requiring
a topical antibiotic
for a corneal ulcer.
Another patient
comes in with bilateral uveitis and
needs a topical steroid. A third patient complains of debilitating ocular allergies. What do these patients
all have in common? They are all
in their first trimester of pregnancy.
So, keeping this in mind, what
criteria do you use to guide your
selection of medications?
Many practitioners have relied
heavily if not exclusively on the
longstanding FDA pregnancy
labeling system for prescription
medications to make this call. First
instituted in 1979 in response to
the thalidomide disaster of the
early 1960s, in which thousands
of babies were born with severely
deformed extremities after the drug
was marketed as a preventative
for morning sickness, the system is
comprised of five categories: drugs
are labeled A, B, C, D or X based
on a series of predetermined FDA
risk factors, with A being considered the safest category. Each category was defined by the absence
or presence of data in animals and/
or humans and the study results.1
Additionally, categories D and X
included information about the
drug’s benefits for the mother, along
with potential fetal risks. The FDA
also determined safety data could
be omitted for drugs that are not
systemically absorbed as well as for
drugs without sufficient studies to
demonstrate risk.2
In the years since the labeling
system’s institution, however, many
8
shortcomings have been identified;
this month’s column will provide
a brief overview of the impetus
for change and what the change
involves.
MAKING THE CHANGE
There are approximately 6.5 million pregnancies annually in the
United States, with an estimated
yearly pregnancy rate among women ages 15 to 44 at 11%.3 In a retrospective study on the prevalence
of prescription drug use among
pregnant women, researchers found
that approximately 64% of women
are prescribed a drug during pregnancy; of those receiving a prescription medication, 50% of the drugs
came from category B, 37.8% from
category C, 4.8% from category D
and 4.6% from category X.2 Other
data has suggested that as many as
80% of women receive prescription
medications during pregnancy, with
an average of 3.1 prescriptions per
person.2 Approximately 66% of
all prescription medications were
labeled as category C.2
The FDA realized as early as
1997 there were problems with
the 1979 labeling, but it has taken
almost two decades for change to
occur. Known problems include
oversimplification of drug use
during pregnancy, the incorrect assumption that all drugs in a particular category share the same risks,
and that supporting test data is not
clearly distinguished as to whether
it is from animals or humans.1,2,5
To overcome these concerns, the
FDA proposed the Pregnancy and
Lactation Labeling Rule (PLLR) in
2008 and, after minor changes, the
final PLLR was adopted effective
June 30, 2015. The most striking
difference between this and the old
labeling system was the elimination
of the pregnancy letter categories.
In addition, the content and format
for the labeling of prescription
drugs and biological products has
been reorganized with changes in
titles and headings:
• Section 8 on every package
insert now addresses prescription
drug use in specific populations.
• Section 8.1 will now be called
“Pregnancy” and will now include
a section on labor and delivery.
Other subcategories will include
“Pregnancy Exposure Registry,”
with directions to include contact
information for enrollment if applicable; “Risk Summary” and “Clinical Considerations and Data.” The
latter two sections will be required
to clearly delineate if the findings
were from human, animal or pharmacology studies.
• Section 8.2 will now be called
“Lactation, including Nursing
Mothers,” which was formerly
Section 8.3. This section will also
contain subsections on risk and
clinical considerations and data,
with similar requirements to Section 8.1.
•The revised Section 8.3 is now
labeled “Females and Males of Reproductive Potential.” This section
will address whether pregnancy
testing and/or contraception are
recommended in conjunction with
the drug therapy. Also addressed in
this section will be any human or
animal data that suggests drugrelated infertility.6-8
Prescription drugs submitted to
008_RCCL0915_PSP.indd 8
8/25/15 10:26 AM
RCCL
REVIEW OF CORNEA
& CONTACT LENSES
11 Campus Blvd., Suite 100
Newtown Square, PA 19073
Telephone (610) 492-1000
Fax (610) 492-1049
Editorial inquiries: (610) 492-1003
Advertising inquiries: (610) 492-1011
Email: [email protected]
EDITORIAL STAFF
FDA Prescription Drug Labeling Changes
Sections 8.1 to 8.3: “Use in Specific Populations”
CURRENT LABELING
NEW LABELING
(effective June 30, 2015)
8.1 Pregnancy
8.1 Pregnancy
Includes Labor and Delivery
8.2 Labor and Delivery
8.2 Lactation
Includes Nursing Mothers
8.3 Nursing Mothers
NEW
8.3
Females and Males of
Reproductive Potential
Source: FDA
EDITOR-IN-CHIEF
Jack Persico [email protected]
SENIOR ASSOCIATE EDITOR
Aliza Becker [email protected]
CLINICAL EDITOR
Joseph P. Shovlin, OD, [email protected]
EXECUTIVE EDITOR
Arthur B. Epstein, OD, [email protected]
ASSOCIATE CLINICAL EDITOR
Christine W. Sindt, OD, [email protected]
CONSULTING EDITOR
Milton M. Hom, OD, [email protected]
GRAPHIC DESIGNER
Matt Egger [email protected]
AD PRODUCTION MANAGER
Scott Tobin [email protected]
BUSINESS STAFF
PUBLISHER
James Henne [email protected]
the FDA for approval after June 30,
2015 will immediately use this new
formatting. Labeling for over-thecounter medicines, however, will
not be affected by the PLLR and
thus will not change. Drug applications approved after June 30,
2001 will have three years to make
labeling changes. Drugs approved
prior to June 30, 2001 will not be
required to reformat the labeling to
be consistent with the new content,
but will be required to remove the
pregnancy risk category (i.e., A, B,
C, D or X) within three years.2,7
Overall, the PLLR is expected
to provide the practitioner with a
better understanding of the risks
associated with prescription medications during pregnancy and lactation. It will equip the clinician with
better information including a summary of the risks of using a drug,
data supporting that summary and
relevant information which will
help when selecting medications
and allow for better communication to the patient about the risks/
benefits to the patient and the fetus.
Additionally, more comprehensive
information will be available as
well for patients of reproductive
008_RCCL0915_PSP.indd 9
potential who may be contemplating pregnancy. Though simplicity
has been eliminated, our pregnant
patients who need prescription
drugs will still benefit from these
significant changes.
RCCL
1. Feibus, KB. FDA’s proposed rule for pregnancy
and lactation labeling: improving maternal child
health through well-informed medicine use. J Med
Toxicol. 2008;4(4):284-288.
2. Ramoz LL, Patel-Shori NM. Recent changes in
pregnancy and lactation labeling: retirement of risk
categories. Pharmacotherapy. 2014;34(4):389-395.
3. Ventura SJ, Curtin SC, Abma, JC, Henshaw SK.
Estimated pregnancy rates and rates of pregnancy
outcomes for the united states, 1990-2008. Natl
Vital Stat Rep 2012;60:1-12.
4. Andrade SE, Gurwitz JH, Davis RL, Chan KA,
et al. Prescription drug use in pregnancy. Am J
Obstet Gynecol. 2004;191(2):398-407.
5. Sannerstedt R, Lundborg P, Danielsson BR,
Kihlstrom I, et al. Drugs during pregnancy: an issue
of risk classification and information to prescribers.
Drug Saf. 1996;14(2):69-77.
6. U.S. Food and Drug Administration. Pregnancy
and Lactation Labeling Final Rule. Available
at: www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/Labeling/
ucm093307.htm. Accessed June 15, 2015.
7. U.S. Food and Drug Administration. Questions
and Answers on the Pregnancy and Lactation
Labeling Rule. Available at: www.fda.gov/Drugs/
DevelopmentApprovalProcess/DevelopmentResources/Labeling/ucm093311.htm Accessed June
15, 2015.
8. U.S. Food and Drug Administration. Content and
Format of Labeling for Human Prescription Drugs
and Biological Products: requirements for pregnancy and lactation labeling. Available at: https://
s3.amazonaws.com/public-inspection.federalregister.gov/2014-28241.pdf. Accessed June 15, 2015.
REGIONAL SALES MANAGER
Michele Barrett [email protected]
REGIONAL SALES MANAGER
Michael Hoster [email protected]
VICE PRESIDENT OPERATIONS
Casey Foster [email protected]
EDITORIAL BOARD
Mark B. Abelson, MD
James V. Aquavella, MD
Edward S. Bennett, OD
Aaron Bronner, OD
Brian Chou, OD
S. Barry Eiden, OD
Gary Gerber, OD
Susan Gromacki, OD
Brien Holden, PhD
Bruce Koffler, MD
Pete Kollbaum, OD, PhD
Jeffrey Charles Krohn, OD
Kenneth A. Lebow, OD
Kelly Nichols, OD
Robert Ryan, OD
Jack Schaeffer, OD
Kirk Smick, OD
Barry Weissman, OD
REVIEW BOARD
Kenneth Daniels, OD
Desmond Fonn, Dip Optom M Optom
Robert M. Grohe, OD
Patricia Keech, OD
Jerry Legerton, OD
Charles B. Slonim, MD
Mary Jo Stiegemeier, OD
Loretta B. Szczotka, OD
Michael A. Ward, FCLSA
Barry M. Weiner, OD
8/25/15 10:26 AM
Practice Progress
By Mile Brujic, OD, and Jason Miller, OD, MBA
Meet the Candidates
More patients can wear contact lenses than you might think. Custom designs can turn
missed opportunities into success stories.
W
ith the year
rolling along,
have you taken
the chance
to evaluate
the progress of your contact lenses
business? Is your growth where
you would like it to be, or are you
experiencing the all-too-familiar
feeling of just treading water? We
all are aware of the often-cited
statistic that about 16% of contact
lens patients drop out of lens wear
each year, essentially eliminating
the gains we might have experienced from new patients entering
the modality. Many practices end
the year with the same number of
contact lens patients they started
with. What will it take to break the
cycle? A broader view of who’s a
candidate for contact lens wear.
Many practices rely on everyday
wearers as their primary source of
contact lens revenue—they’re easy
to fit and easy to please—but forgo
considering specialty and custom
contact lens wearers. Patients with
unique visual demands and/or more
challenging ocular anatomy to contend with have often been told they
cannot wear contact lenses, due to
an irregular cornea or high amount
of astigmatism. Others who wore
contact lenses previously may have
given up due to discomfort or fit
issues. While these patient types will
take a bit more effort and expertise than a garden-variety -3.00D
myope with healthy eyes, when
handled correctly they can be your
biggest catalysts for growth.
In this newly retooled column,
now called Practice Progress, we’ll
focus on strategies for growth
10
as well as retention. Success in a
contact lens practice requires more
than just “derailing dropouts,” the
topic we addressed for the last eight
years. It also takes a willingness to
embrace new ideas, lens technologies and challenges. Custom-fitting
contact lenses for challenging cases
is the perfect place to start.
SPREAD THE WORD
The first step to getting these patients on your side is making them
the offer of custom lenses. It sounds
simple, but many patients have
preconceived notions that they cannot wear lenses. Once the patient
expresses interest in trying a custom
lens, record their history, including
their occupation, hobbies and daily
visual requirements, and discuss
suitable lens options with them.
Technology can aid with determining the correct lens option for each
patient. Topography is a must for
corneal mapping, while anterior
segment OCT can aid in fitting
vaulted lenses. Newer OCT applications can image the tear film to get
a better sense of tear dynamics, so
even borderline dry eye patients can
wear contact lenses.
Custom contact lens offerings
comprise a large number of lens
types, including those for high and
irregular astigmatism, keratoconus,
post-traumatic and post-refractive
corneas, myopia control, poor visual acuity and ocular surface disease.
Because of the uncommon nature
of some of these lenses, fitting these
patients often takes more time and
energy; thus, many practitioners
don’t even make the offer. Below,
we review a few patient populations
who have custom lens options to
consider.
HIGH ASTIGMATIC PATIENTS
These patients offer a good opportunity to add a significant number
of underserved contact lens wearers
to your office. While there are many
toric options available in the soft
contact lens market, on-eye lens stability can sometimes be a challenge
for those with moderate to high
levels of astigmatism, especially of
the irregular variety. Uncorrected
astigmatism and the subsequent distorted vision results in frustration,
headaches and eye fatigue.
For these patients, gas permeable (GP) lenses provide more
stable vision than traditional soft
lenses and mask corneal irregularities. Though GPs typically require
longer adaptation times, spherical
GPs are often a great starting lens.
However, patients with significantly
higher astigmatism (i.e., more than
3.00D cyl), may need a back toric
or bitoric GP lens to further ensure
lens stabilization.
ASTIGMATIC PRESBYOPES
Another great opportunity to
improve the patient’s contact lens
experience is the high astigmat with
presbyopia. GPs can often be fit
empirically for these patients and
typically provide the greatest range
of clear vision at all focal lengths
near to distance. GP multifocals
are often the best way to ensure
good visual function. These lenses
are typically customized to the
patients’ specific cornea shape and
visual needs. Note that some lens
movement is necessary, but signifi-
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Fig. 1. The center optic zone is apparent
in this photo. The NovaKone (Alden) has
variable lens center thickness (IT Factor)
to neutralize irregular astigmatism;
however, a higher IT Factor is necessary
for more advanced levels of keratoconus.
cant movement will impede visual
function.
Soft toric multifocals are another
good option for these patients. To
properly fit theses lenses, fit the
toric aspect first and adjust for rotation and instability before fitting the
multifocal aspect. As with any lens,
be sure to discuss appropriate visual
expectations and the importance of
follow-up care. For this technology,
on-eye stabilization is key.
Hybrid lenses are a third possibility for patients who desire the clear
vision of GP lenses with the comfort of soft lenses, as the soft skirt
surrounding the rigid center helps
reduce lens awareness. The secondgeneration Duette multifocal lenses
(SynergEyes) are currently the only
hybrid lens with a silicone hydrogel
skirt (Dk=84).
CORNEAL IRREGULARITIES
There are a number of scleral
lens designs available for corneal
irregularities like keratoconus, posttrauma and post-surgery, includ-
ing corneal-scleral, semi-scleral,
mini-scleral and conventional
scleral fits. These rigid lenses are
becoming increasingly popular due
to their ability to mask irregularities
while being better tolerated than
traditional corneal GPs. As scleral
lenses are fit to vault the cornea,
much of the lens rests on the sclera,
as opposed to the cornea. Typically, their diameter is greater than
10mm; fitting sets are a must for
this technology.
Additionally, there are a few soft
designs for the irregular cornea.
These lenses typically use thicker
center optic zones to mask irregularities. Some limits exist with
these designs, but they may be a
good option for mild to moderately
distorted corneas.
CASE IN POINT
A new 44-year-old male patient
presented with complaints of
decreased vision with his glasses
at distance and near. He reported
his vision was worse in his right
eye and that he had been told at
his previous eye exam that he may
have keratoconus; however, he had
never been fit with contact lenses.
His BCVA was 20/30 OD with an
Rx of +2.50-4.00x049 and 20/20
OS with an Rx of +0.75-2.00x132.
He was trial fit into the NovaKone
(Alden) soft keratoconic contact
lens, and later fit with the NovaKone Toric for his right eye and the
NovaKone Sphere for his left eye
(Figure 1). His vision with contact
lenses was equal to his best corrected spectacle prescription, and
he expressed satisfaction with his
vision and comfort.
DEVELOPING YOUR MARKET
Though you have an existing
patient base to draw from, it is
important to develop marketing
tactics to expand this group. Some
possibilities include talking to other
doctors in the area—including ophthalmologists, primary care practitioners and even school nurses—to
spread the word of your ability to
fit custom lenses. These professionals would welcome the opportunity
to help their patients and would
have no problem admitting their
shortcomings in this particular area
of care; knowing a specialist to refer
their patients to gives them the ability to help without the obligation of
developing the expertise in-house.
In addition, consider external
and internal advertising efforts such
as newsletters, emails, websites
and social media outlets. Don’t
forget to capture the reaction of
your patients as they experience a
successful fit and use it to promote
your practice. For instance, a happy
patient who’s just been fit with a
custom lens might want to post a
selfie right from your exam chair,
providing everyone in their social
network with an endorsement for
your practice. Boom—instant, realtime marketing. And it’s free.
The above options offer a unique
platform and design, which allows
the contact lens practitioner to
provide unique products to your
patients. Some patients will be
intolerant of any lens design, but
in those instances where a patient
would benefit from the optics that
a GP delivers, but cannot wear the
lenses because of discomfort issues,
consider a soft or hybrid lens.
RCCL
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Making the
Case For
By Robert Ensley, OD
Custom Lenses
A
lthough contact
lenses are classified
as medical devices
and subject to the
same stringent FDA
approval process as cardiac stents,
orthopedic implants and any other
manufactured health aid, they are
increasingly seen by many as a
commodity. Before the era of mass
production, conventional contact
lenses were lathe-cut and made
to order, with varying diameters
and base curves. Then, in the late
1980s, the first disposable soft
contact lenses were produced using
a cast-mold production process,
forever changing the industry.
Since then, stock lens offerings
have increased exponentially.
Patients enter a competitive consumer environment upon leaving
the exam room, one that is
complicated by a range of discount
vision plans and online retailers
who emphasize cost savings and
little else.
In light of this downgrade
of contact lenses in the public
sphere—from medical device to
commodity product—it is easy to
12
see why many patients lose sight of
the value of our expertise in choosing an appropriate lens. This trend
is especially concerning for patients
with higher demands on their vision who have struggled to find an
appropriate stock lens. Educating
patients regarding your ability to
personalize their fit with customdesigned lenses can help you better
meet their needs and stand apart
from competition.
POTENTIAL CANDIDATES
By definition, a custom contact
lens is any soft, gas permeable (GP)
or hybrid lens design that is made
to order, with multiple design parameters that can be manipulated.
Although irregular cornea applications may come to mind first as the
best use of custom lenses, they can
address many patients' refractive
needs that are not being met with
standard “off-the-rack” disposable
contact lenses.
• Astigmatic Patients. How
often do patients mention they
have been told they cannot wear
contact lenses because of their
astigmatism? An estimated 90%
of astigmatic patients can be fit
in the parameters available with
stock soft toric lenses, which typically includes a range of +6.00D
to -9.00D in spherical power and
up to -2.25D cylinder power.1
For patients outside of this range,
custom soft toric lenses are an
option. Depending on the laboratory, from 8.00D up to 12.00D of
astigmatism can be incorporated
with one-degree axis steps. With
larger amounts of astigmatism,
cylindrical axis refinement is critical. Custom lenses can be lathe-cut
to nearly any base curve, diameter
and prism to improve rotational
stability.
When patients express a desire
for better vision, consider discussing GP lenses, as they offer a
ABOUT THE AUTHOR
Dr. Ensley is in private practice
in Louisville, Ky., where
he specializes in fitting
specialty contact lenses.
He completed a residency
in cornea and contact lenses
at the University of MissouriSaint Louis and is a Fellow of the
American Academy of Optometry.
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SPECIAL
SPECIAL
S
SP
PECIA
ALISSUE:
IS
ISSUE:
SSU
UE:
CUSTOM
CUSTOM
C
CU
USTOM
M LENSES
L
LENSES
EN
NSES
Finding a lens for every patient can boost your practice and your profits.
superior quality of vision compared with soft toric lenses.2,3 As
a general rule of thumb, spherical
GPs can be used when refractive astigmatism equals corneal
astigmatism of less than 2.5D. If
there is any residual astigmatism, it
can be applied to the front surface.
However, in cases of higher corneal
astigmatism, back-surface or bitoric GPs are typically used.
If initial comfort with corneal
GP lenses is a concern, consider
prescribing hybrid or scleral lenses
instead. Many GP laboratories are
now marketing smaller diameter
scleral lenses to fit the “normal”
cornea. These specialty lenses provide stable, higher quality vision
with comfort rivaling soft toric
lenses.4
• Corneal Shape. Most stock
soft lenses take a “one-size-fits-all”
approach, with only one diameter
and one base curve to choose from.
If two base curves are available,
however, the choice is most often
made using keratometry readings.
Sagittal depth of the cornea, which
is influenced by corneal diameter,
may also play a significant role
in the lens-cornea fitting relationship. Corneal diameter is typically
measured by horizontal visible
iris diameter (HVID), with average corneal diameter measuring
11.8mm.5,6 Patients with an HVID
outside the typical range can
expect a lens to decenter, reducing both the patient’s quality of
vision and comfort. To solve this,
base curves and diameter can be
manipulated with custom lenses to
change the overall sagittal depth
of a lens and thus better match
corneal shape.
• Presbyopes. The strain placed
on near vision in our technologydriven world, coupled with the influx of presbyopic patients, has put
multifocal lenses more in demand
than ever. The ability to change
multiple design parameters once
again increases the odds for success. Knowing the patient’s desired
working distance can help in the
decision-making process. If higher
add powers are required, many GP
multifocals have adds greater than
3.0D. Certain custom laboratories
such as SpecialEyes can manufac-
ture lenses with an add power up
to 4.0D at 0.10D increments.
Most gas permeable and custom
soft multifocals rely on aspheric,
simultaneous vision designs.
Depending on the specific design
of the lens, adjusting zone sizes inf
relation to pupil size can improve
the optics. For example, if a centerdistance, aspheric GP multifocal
has a standard distance zone of
3.95mm, patients with a smaller
pupil diameter may have difficulty
achieving great near vision, while
those with larger pupil diameters
Case #1: The Presbyope with Large HVID
A 44-year-old
pilot presented complaining of decreased near
vision with
his habitual
progressive
add spectacles. He was interested in trying contact lenses for the
first time. Given his occupation, there is a high demand on
his vision at various working distances. Spectacle Rx was
0.00 0.75x090 OD and 0.00 0.50x095 OS, with an add
of +1.50. Keratometry readings were 42.25/42.75 at 180
OU. A pair of standard center-near monthly replacement
multifocals was placed on his eyes, but were decentering
superiorly with excessive movement.
A pair of custom center-near aspheric soft multifocals
was ordered using spherical equivalent power for the
distance correction. The base curve and diameter was
adjusted to 8.4mm and 15.2mm OU to improve the fitting
relationship. Given a pupil diameter of 4.0mm in ambient
light, the center-near zone was set at 2.0mm extending
to a 3.5mm intermediate zone. With these lenses, he was
able to comfortably achieve 20/20 distance vision in each
eye and read his phone and an iPad that he uses in the
cockpit.
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MAKING THE CASE FOR CUSTOM LENSES
Case #2: The High Astigmat
A 24-year-old graduate student presented wearing soft
toric lenses, but only part-time because he reported that vision is better in spectacles.
In addition to better clarity
when using spectacles, he
reported fluctuating vision
when blinking in his contact lenses.
His Rx was -10.50
3.00x005 OD and -11.50
2.00x160 OS with keratometry readings of
43.25/45.25 at 089 OD
and 43.50/44.75 at 074
OS. Because of the potential for residual astigmatism in a GP lens, a custom soft toric
lens was initially chosen.
Custom soft toric lenses were empirically ordered using
the Definitive (efrofilcon A, Contamac) material. Given his
significant level of myopia and thicker lens periphery, a silicone hydrogel material was preferable. After vertexing, the
following lenses were ordered: -9.25 2.75x005 with an 8.2
base curve and 14.8 diameter OD and -10.25 1.75x160 with
an 8.3mm base curve and 14.8mm diameter. He was able
to achieve stable, 20/20 vision in each eye and was thrilled
with his vision. He is now wearing his contact lenses daily.
may have shadowing and glare at
distance, especially in scotopic conditions. Center-near custom soft
multifocals allow both near and
intermediate peripheral zones to be
adjusted dependent on pupil size.
Patients looking for crisp,
uninterrupted vision at both distance and near may do better in a
translating GP multifocal because
it avoids the inherent limitations
of simultaneous vision designs.
However, pay careful attention to
lower lid anatomy before beginning the fitting process to make
sure the lens can rest appropriately
on the lid and translate upward
as needed. The lower lid should
be at or within 1mm from the
limbus, without significant laxity,
to allow for appropriate transla-
14
tion. If centration or comfort is a
concern, you may consider fitting hybrid or scleral multifocals.
Scleral multifocals may serve a
dual purpose—that is, correcting
presbyopic refractive error and
treating underlying dry eye.
• Myopia Control. Many practitioners are now using contact
lenses for myopia control—in
fact, an audience poll at the 2014
American Optometric Association
(AOA) annual meeting found that
32% of participants prescribed soft
multifocal lenses and 29% prescribed orthokeratology lenses for
this purpose.7
A recent myopia control study
with soft multifocal contact lenses
used a center-distance design with
a +2.00D to reduce peripheral
blur.8 Currently, the only massproduced lenses that can provide
such a design include the Biofinity
Multifocal (Cooper Vision), Proclear Multifocal (Cooper Vision)
and Acuvue Oasys for Presbyopia
(Johnson & Johnson Vision Care).
This presents an opportunity for a
custom multifocal. The ability to
adjust zone sizes, incorporate astigmatism power and increase the add
power, if tolerated, can increase
the likelihood of successful wear.
Additionally, a custom lens may
help reinforce both the off-label
nature and extra level of care you
are providing to the patient.
Orthokeratology lenses, which
are custom GPs with a reverse
geometry design, for corneal correction if daytime lens wear is
either uncomfortable or not an
option due to environmental or
occupational reasons. These lenses
are more commonly prescribed
for children, but can be worn by
adults as well and are fit both diagnostically and empirically.
PERSONALIZED FITTING
Identifying candidates for custom
contact lenses begins with taking
a case history. Many non-contact
lens wearers believe their prescriptions exclude them from contact
lens wear. Similarly, for both
current and former contact lens patients, inquiring about their wearing experiences can help you better
tailor a custom lens option for
them. Once the need for a custom
lens is established, patients can be
fit diagnostically or empirically.
Diagnostic fitting evaluates the
lens-to-cornea fitting relationship
of various lenses; however, this
approach may increase chair time
during the initial evaluation. Certain lenses, including translating
GPs and scleral lenses, are better fit
diagnostically.
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Because most practices do not
carry a large GP inventory or multiple diagnostic sets, empirically
ordering GP lenses is often the
preferred approach for many practitioners. In addition to potentially
reducing chair time, empirically
designed GPs have been proven to
be accurate.4 When ordering empirically, manifest refraction and
keratometry readings are required
for GP, hybrid and custom soft
lenses. Choosing the initial lens
diameter for a GP lens can be done
after assessing the upper eyelid
position. Generally, if the eyelid
is positioned at or near the upper
limbus, a lid-attached fit can be
achieved with a diameter of 9.4mm
or greater. An interpalpebral fit
may require a smaller, steeper lens
with a diameter of 9.2mm or less.
Fitting toric GPs may seem
intimidating, but there are multiple
fitting nomograms and resources
available to help design these
lenses, such as www.gpli.info/lenscalculator/. Using spectacle refraction and keratometric readings,
the lens calculator will recommend
either a spherical or toric GP lens,
and will provide parameters. For
presbyopic patients being fit with
either GP or custom soft multifocals, measuring pupil size in both
photopic and scotopic conditions can help determine initial
zone sizes. Keep in mind that add
power may vary depending on the
patients’ most desired working
distance.
Corneal topography is a great
tool to use when fitting custom
lenses. Multiple measurements
such as keratometric readings,
HVID, pupil size and corneal eccentricity can be obtained in a matter of minutes. Additionally, many
topography software programs can
simulate sodium fluorescein pat-
Case #3: The Astigmatic Athlete
A 23-year-old professional baseball player presented to the
office for contact lens evaluation. He was wearing standard soft toric lenses, but complained of fluctuating vision.
As a competitive athlete, it was critical that his vision be
as crisp and
stable as possible. His Rx was
+1.00 1.75x097
OD +1.25
2.00x071 OS,
with keratometry readings
of 41.75/43.00
at 003 OD and
41.75/43.50 at
167 OS.
We selected
hybrid lenses to
provide GP optics without the concern for lens rotation or dislodgement.
The lenses provided 20/15 vision in each eye. The patient
reported they were both comfortable.
terns of a calculated contact lens.
Custom lenses also differ in care
requirements compared to “offthe-rack” lenses. Replacement
schedules vary depending on the
type of lens and the discretion of
the prescribing doctor, but typically range from quarterly to annually. Proper care and disinfection is
essential to maintaining the life of
each lens. In addition to standard
disinfection systems, additional
solvent cleaners or enzymatic
cleaners can be used periodically.
Custom contact lenses can be a
tough sell to patients used to the
simplicity of online ordering and
instant gratification. But just as a
tailored suit looks and feels better
than a department store’s in-stock
options, lenses created expressly
for each individual’s visual needs
and ocular anatomy will perform
better. With a little extra attention
during the fit and careful patient
education, you can create a truly
individualized approach that gives
patients superior outcomes and reinforces your expertise. The result?
Happier, more loyal patients and a
healthier bottom line.
RCCL
1. Young G, Sulley A, Hunt C. Prevalence of astigmatism in relation to soft contact lens fitting.
Eye & Contact Lens. 2011;37(1):20-5.
2. Michaud L, Barriault C, Dionne A, Karwatsky P.
Empirical fitting of soft or rigid gas-permeable
contact lenses for the correction of moderate
to severe refractive astigmatism: A comparative
study. Optometry. 2009 Jul;80:375-83.
3. Fonn D, Gauthier CA, Pritchard N. Patient
preferences and comparative ocular responses
to rigid and soft contact lenses. Optom Vis
Sci.1995;72(12):857-63.
4. Michaud L, Woo S, Dinardo A, et al. Clinical
evaluation of a large diameter rigid gas-permeable lens for the correction of refractive
astigmatism. Poster presented at the American
Academy of Optometry Annual Meeting. 2012;
Phoenix, AZ.
5. Douthwaite WA. Initial selection of soft
contact lenses based on corneal characteristics.
CLAO J. 2002. Oct;28:202-5.
6. Caroline P, André M. The effect of corneal
diameter on soft lens fitting, part 1. Contact Lens
Spectrum. 2002;17(4)56.
7. Quinn TG, Walline JJ, Sonsino J, et al. Controversies in contact lens care. Contact Lens Spectrum.
2015;30(1):34-40.8. Walline JJ, Greiner KL, McVey
ME, Jones-Jordan LA. Mulitfocal contact lens
myopia control. Optom Vis Sci. 2013;90:07-1214.
014_RCCL0915_F1.indd 15
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8/25/15 12:49 PM
7.38
10.4/0.2
7.42
10.4/0.2
7.46
10.5/0.2
7.50
10.5/0.2
7.54
10.6/0.2
7.58
10.6/0.2
7.63
10.6/0.2
7.67
10.7/0.2
7.71
10.7/0.2
7.75
10.8/0.2
7.80
10.8/0.2
7.85
10.9/0.2
7.89
10.9/0.2
7.94
4
11.0/0.2
7.99
7
99
9
11.0/0.2
8.04
8
11.0/0.2
8.08
8.
8
11.1/0.2
8.1
8.
8.13
11.1/0.2
8.18
18
18
11.2/0.2
8.23
11.2/0.2
G
GPs:
as permeable (GP)
lenses tend to be
our “go-to” option
for specialty contact
lens fits. However,
while their use is intuitive for cases
of keratoconus and other irregular
astigmatic corneas, many other
patients would benefit from the
crisp vision GP lenses provide
or the additional health benefits
associated with their use. The wide
availability of soft lens modalities
and parameters, coupled with the
added time and complexity of
fitting GP lenses rather than soft
lenses, means that GPs comprise
less than 10% of total fits today.
In reality, GP lens fitting is
straightforward, especially when
you have the appropriate tools of
the trade—diagnostic GP fitting
sets—at your fingertips. Forgoing fitting the lens empirically and
observing it yourself on the eye
will allow you to make a more
informed decision on what parameters will work best for your patient.
Let’s look at both empirical and
diagnostic fitting methods.
EMPIRICAL FITTING
This approach involves fitting a
GP lens based on manufacturer
guidelines, K readings and refrac-
16
An expert walks you through the finer points of
the process to help you achieve better results.
tive measurements. As the simplest
method, it saves chair time.1 Recent
manufacturing improvements such
as the advent of aspheric lathes and
more consistent edge profile designs
and minimal center thicknesses
have further increased its success
rate.
The downside of empirical fitting
is that success with the first lens
fitted is only about 40% when employing K readings and refractive
measurements.2 Use of topographic
software as well as incorporation
of the Sim K information and the
patient’s corneal e-values or asphericity can help make the lens design
more accurate, however. Many
corneal topographers are capable
of generating a pseudo-fluorescein
pattern based on the lens design
(i.e., spherical, aspheric and even
toric) desired, allowing practitioners to order lenses without the
initial placement of a lens on the
patient’s eye.
Empirical lens fitting can also
be done using online resources
(such as those found at GPLI.org)
or smartphone apps like EyeDock
(www.eyedock.com). However,
empirical lens fitting without the
advantages of topography and
computer-assessed pseudo-fluorescein patterns is likely to result in
more lens orders and exchanges
until the patient is appropriately
fit. This ultimately results in more
office time and possibly less patient
confidence in the practitioner than
would have occurred had the fitting
been done with the benefit of a
diagnostic GP lens evaluation.
DIAGNOSTIC GP
LENS FITTING
This technique provides the advantage of observing one or more
test lenses, which are similar to
the empirical lens values described
above, on the patient’s eyes prior
to ordering. In this case, the lenses
that provide the best lens-to-cornea
relationship, as well as good centration and movement, are the ones
that should be chosen. Diagnostic
lens fitting provides important
information as to what visual
acuity can be achieved. Residual
ABOUT THE AUTHOR
Dr. Silbert is a professor of
optometric medicine at
Pennsylvania College of
Optometry, Salus University.
He is also the director of
cornea and specialty contact
lens services at the Eye
Institute of Salus University. He
has no financial interests in any of
the lens materials or designs discussed in this
article, nor any financial interests in any of the
companies’ products mentioned herein.
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SPECIAL ISSUE:
CUSTOM LENSES
Are You Making
Good Use of
Diagnostic Fitting
Sets?
By Joel A. Silbert, OD, FAAO
Table 1. Fixed Diameter GP
Spherical Diagnostic Fitting Set
• Diameter 9.4/8.0 (or 9.2/7.8)
• Power -3.00D
• Peripheral curves are tetracurve design,
similar to the Bennett system8
• Center thickness 0.14mm standardized
BCR
SCR/W
ICR/W
PCR/W
7.38
8.2/0.3
9.2/0.2
10.4/0.2
7.42
8.2/0.3
9.2/0.2
10.4/0.2
7.46
8.3/0.3
9.3/0.2
10.5/0.2
7.50
8.3/0.3
9.3/0.2
10.5/0.2
7.54
8.3/0.3
9.3/0.2
10.6/0.2
7.58
8.4/0.3
9.4/0.2
10.6/0.2
7.63
8.4/0.3
9.4/0.2
10.6/0.2
7.67
8.5/0.3
9.5/0.2
10.7/0.2
7.71
8.5/0.3
9.5/0.2
10.7/0.2
7.75
8.6/0.3
9.6/0.2
10.8/0.2
7.80
8.6/0.3
9.6/0.2
10.8/0.2
7.85
8.7/0.3
9.7/0.2
10.9/0.2
7.89
8.7/0.3
9.7/0.2
10.9/0.2
7.94
8.8/0.3
9.8/0.2
11.0/0.2
7.99
8.8/0.3
9.8/0.2
11.0/0.2
8.04
8.8/0.3
9.8/0.2
11.0/0.2
8.08
8.9/0.3
9.9/0.2
11.1/0.2
8.13
8.9/0.3
9.9/0.2
11.1/0.2
8.18
9.0/0.3
10.0/0.2
11.2/0.2
8.23
9.0/0.3
10.0/0.2
11.2/0.2
astigmatism, if significant,
is often observed along
with reduced acuity; this
improves once additional
astigmatic correction is
provided via over-refraction. Its presence may
indicate that the lens is too
thin, and flexing on the
eye. Conversely, in some
cases residual astigmatism
may be higher with more
rigid (thicker) lenses; thus,
thinner lenses would in
fact be more beneficial.3
Patients who undergo diagnostic lens fitting should
be forewarned of the differences between GPs and
soft contact lenses. Many
GP lens patients experience
excessive lacrimation and
foreign body sensation as a
result of initial lens placement, so use proparacaine
during initial diagnostic
lens fitting to numb the
eye. Additionally, while the
initial test lens applied to
the patient’s eyes may not
enable them to see clearly
immediately, performing
an over-refraction can assure them that vision will
be correctable to excel-
lent levels similar to what they may
enjoy with their glasses.
Diagnostic lens fitting is highly
likely to result in fewer lens changes
or reorders, as the fitting gives the
practitioner a great deal of information, increasing confidence in the
lens fitting process. Patient satisfaction is also quite high, despite the
added time commitment diagnostic
fitting may entail compared with
soft lens fittings.
Empirical lens design is not
advised in cases where specialized
lenses are needed, such as with
keratoconus or post-keratoplasty
patients, and with ortho-keratology
fittings. In these cases, specialized
diagnostic fitting sets are required
to properly assess lens performance,
vision and proper lens-to-cornea fitting relationships. This is especially
true for patients with keratoconus
due to the different cone shapes and
locations; patients with pellucid
marginal degeneration who require
much larger GP lenses to assist in
lens centration; and patients who
wear bifocal lenses due to variations
in pupil size and GP lens designs
(i.e., center distance, center near,
concentric, spherical and aspheric.)
One exception is the ReClaim HD
lens (Blanchard), a multifocal GP
lens designed to be fit empirically.
016_RCCL0915_F2.indd 17
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GPs: ARE YOU MAKING GOOD USE OF DIAGNOSTIC FITTING SETS?
Table 2. Variable Diameter GP Diagnostic Fitting Set
• Diameter varies with base curve (BC)
• Back Vertex Power (BVP) varies with BC
• PCs standardized to provide relatively constant edge lift (0.09-0.11mm)
BCR
Back Vertex Power
Diameter/OZD
SCR/W
ICR/W
PCR/W
8.40 (40.25)
-2.00D
9.6 / 8.2
9.2 / 3
10.2 / 0.2
11.6 / 0.2
8.30 (40.62)
-2.00D
9.6 / 8.2
9.1 / 3
10.1 / 0.2
11.5 / 0.2
8.20 (41.12)
-2.00D
9.6 / 8.2
9.0 / 3
10.0 / 0.2
11.4 / 0.2
8.10 (41.67)
-2.00D
9.4 / 8.0
8.9 / 3
9.9 / 0.2
11.3 / 0.2
8.00 (42.25)
-2.00D
9.4 / 8.0
8.8 / 3
9.8 / 0.2
11.2 / 0.2
7.90 (42.25)
-3.00D
9.4 / 8.0
8.7 / 3
9.7 / 0.2
11.1 / 0.2
7.80 (43.25)
-3.00D
9.4 / 8.0
8.6 / 3
9.6 / 0.2
11.0 / 0.2
7.70 (43.75)
-3.00D
9.4 / 8.0
8.5 / 3
9.5 / 0.2
10.9 / 0.2
7.60 (44.37)
-3.00D
9.4 / 8.0
8.4 / 3
9.4 / 0.2
10.8 / 0.2
7.50 (45.00)
-3.00D
9.4 / 8.0
8.3 / 3
9.3 / 0.2
10.7 / 0.2
7.40 (45.62)
-4.00D
9.2 / 7.8
8.2 / 3
9.2 / 0.2
10.6 / 0.2
7.30 (46.25)
-4.00D
9.2 / 7.8
8.1 / 3
9.1 / 0.2
10.5 / 0.2
7.20 (46.87)
-4.00D
9.2 / 7.8
8.0 / 3
9.0 / 0.2
10.4 / 0.2
7.10 (47.50)
-4.00D
9.2 / 7.8
7.9 / 3
8.9 / 0.2
10.3 / 0.2
Blanchard does not make diagnostic fitting sets available; instead,
an online calculator employing K
readings (or Sim Ks) and refractive
data will inform the practitioner
about the lens parameters that will
be provided, and give him/her the
ability to adjust add power and
other parameters if desired. Note, if
residual astigmatism is calculated to
be excessive or if inadequate levels
of plus reading power would be
produced by the lens rear surface
aspheric geometry, other options
need to be explored through consultation.
Toric GP lenses are often calculated empirically, and frequently
with the assistance of the MandellMoore Bitoric Fitting Guide (available at www.gpli.info/mandellmoore). This step-by-step empirical
method does all the calculations
necessary to produce a first bitoric
lens for the moderate to highly
astigmatic contact lens patient. It
18
provides a good starting point,
and in many cases works well
in designing a lens that does not
need a lot of additional parameter
manipulation.4 Use of diagnostic
spherical power effect (SPE) fitting
sets, in which each lens in the set
is pre-designed with spherical lens
optics, makes diagnostic lens fitting
extremely easy; the fluorescein
analysis that an SPE bitoric fitting
set provides enables the practitioner
to rapidly select the right amount
of rear surface toricity, and then
determine the correct power rapidly
through over-refraction.5-7
DIAGNOSTIC FITTING OF
CONVENTIONAL GP LENSES
When fitting conventional corneas
(i.e., to correct astigmatism, provide sharper visual acuity or slow
pediatric myopic refractive error), it
is recommended to have more than
one diagnostic GP lens set—for
example, an average diameter GP
fitting set and a larger diameter set
for “under-the-lid” fitting, which
is typically more comfortable and
more easily centered. Conventional
GP fitting sets on average measure
9.2 to 9.4mm in size, with an optic
zone diameter 1.4mm smaller than
the total diameter.8 Powers for these
lenses are typically made in -3.00D,
as this is close enough for most patients’ refractive errors to be within
a range such that over-refractions
do not need to be adjusted further.
While there can be variations
with high or low Dk GP lens
materials, diagnostic sets are best
manufactured in a mid-range Dk
material with a low wetting angle
to ease tear spreading on the lens
surface. While many practitioners
may have fitting sets in both low
Dk and high Dk materials, a Dk of
somewhere between 30 and 60 is
recommended. As there are many
peripheral curve formulas available, it is best to standardize these
in the set’s diagnostic lenses using
a formula that ensures the secondary curve (SCR), intermediate
curve (ICR or TCR) and peripheral
curve (PCR) have the same flattening relationship predicated on the
selected base curve.
An example of a 20-lens diagnostic fitting set is seen in Table 1.
These can be manufactured by any
CLMA contact lens laboratory, and
are typically provided to the practitioner at very lost cost (assuming of
course that the practitioner orders
their lenses through the manufacturing CLMA laboratory).
In addition to the standard fitting
set mentioned above, it is prudent
to have another in high minus
powers (with plus lenticulated
edges) and one in high plus powers (with minus carrier lenticulated
edges). These supplementary sets
provide more accurate information
regarding how lenses center, as the
016_RCCL0915_F2.indd 18
8/25/15 12:49 PM
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RCCL0915_Hydrogel.indd 1
8/24/15 9:40 AM
GPs: ARE YOU MAKING GOOD USE OF DIAGNOSTIC FITTING SETS?
average thickness of the lenses in
these various powers would differ
and thus affect lens positioning. In
cases where this is not economically
feasible, a standard set of -3.00D
power will usually suffice, as it
reflects the most typical patient
refractive powers seen in practice.
Another option for a practitionerdesigned supplementary diagnostic
fitting set is one with a variable
diameter (i.e., larger lenses for
flatter corneas and smaller lenses
for steeper corneas). This set could
also have variable lens powers,
with lower powers for flatter lenses
and higher powers for steeper base
curves. Table 2 represents a 20lens diagnostic set designed by the
author and manufactured by Valley
Contax for use in an optometric
training program.
When cost is not a factor, such
as in an institutional practice or
large group practice, having a
large inventory of GP lenses made
in a variety of base curves for the
most commonly prescribed myopic
powers (i.e., from -1.25D through
-5.00D in 0.25D steps). For example, having a 200-lens inventory
set would make it easy to dispense
lenses directly out of inventory even
on the first visit, as typically is done
with hydrogel replacement lenses.
This would help reduce dispensing
delay and make parameter changes
easy, as well as enable instant lens
replacement for patients who lose
or damage their lenses. Maintaining the inventory is critical to this
method’s success; while initially
expensive, it does provide good
economy of time and in patient
satisfaction.9
While there is a place for empirical fitting of GP lenses, practitioners should remember the use of
diagnostic lens fitting sets, whether
for conventional lens design, or for
more complex lenses, can only lead
20
to more accurate and satisfying use
of these wonderful devices.
RCCL
1. Benoit DP, Ames KS. Diagnostic versus empirical fitting. Contact Lens Spectrum. 2010;25(4):1213.
2. van der Worp E, de Brabander J, Lubberman
B, et al. Optimising RGP fitting in normal eyes
using 3D topography data. Cont. Lens Anterior
Eye. 2002;11:1-5.
3. Harris MG. Contact lens flexure and residual
astigmatism on toric corneas. J Am Optom Assoc. 1970;41(3):247-248.
4. Mandell RB, Moore CF. A bitoric lens guide
that really is simple. Contact Lens Spectrum.
1988;3(11):83-85.
5. Sarver MD, Kame RT, Williams CT. A bitoric rigid gas permeable contact lens with
spherical power effect. J Am Optom Assoc.
1985;56(3):184-189.
6. Silbert JA. Rigid Contact Lens Correction
of Astigmatism. In: Bennett ES, Weissman BA
(eds.): Clinical Contact Lens Practice, 2nd ed.
Butterworth-Heinemann, 2004.
7. Silbert JA. Benefits of diagnostic fitting for
bitoric GP lenses. Optometric Management.
2007;42(2):54-59.
8. Bennett ES, Sorbara L, Kojima R. Gas-Permeable Lens Design, Fitting, and Evaluation.
In: Clinical Manual of Contact lenses, 4th ed.
Wolters Kluwer, Lippincott Williams & Williams,
2014:112-156.
9. Keech P. The top 10 reasons to inventory RGPs.
Contact Lens Spectrum. 1996;11(10):32-36.
Storing and Maintenance of Diagnostic Sets
While it is possible to store diagnostic GP lenses in disinfecting solution, which also serves to improve on-eye wettability,
it is not practical. Lenses that are not used regularly are more
likely to adhere to the case and subsequently warp, as wet
storage is likely to dry out via evaporation. Secondly, as disinfecting solutions are not approved for use for more than a 30
days, lenses would have to be recleaned and placed in fresh
solution regularly. In a busy practice, this is unlikely to happen;
thus, storing diagnostic lenses dry is more practical. Lenses
can be kept in flat-packs, which take up very little space.
After a diagnostic lens has been used, it should be rubbed
and rinsed with a lens cleaner and then disinfected before being blotted and and stored dry. The CDC (Centers for Disease
Control and Prevention) recommends hydrogen peroxide to
disinfect GP lenses. While many practitioners suggest a fiveto 10-minute soak with an approved peroxide disinfection
system such as ClearCare (Alcon) or PeroxiClear (Bausch +
Lomb), proper disinfection generally requires a full four hours.
When a lens is to be reused, it should be first cleaned using
an approved cleaner (alcohol-based cleaners are very effective for this purpose), rinsed and applied with a wetting or
conditioning solution. Use of a conditioning solution is also
recommended for six to 24 hours prior to delivery when dispensing a new set of lenses to the patient to ensure the base
curve of the lens is properly hydrated.
In the rare case that a newly-dispensed GP lens is nonwetting, it is usually due to a hydrophobic zone on the lens
caused by a waxy or pitch-like residue left from the lens
blocking process. This can be readily remedied by cleaning
the lens in-office; the author recommends FluoroSolve (Paragon), which dissolves waxy residue to enable tears to spread
more effectively on the lens surface. The FluoroSolve should
then be rinsed off and the lens cleaned and hydrated using an
alcohol-based lens cleaner and conditioning solution, respectively, before re-insertion. If FluoroSolve is not available, an
alcohol-based cleaner like as Miraflow or a generic equivalent
can be used alone to restore the lens surface.
016_RCCL0915_F2.indd 20
8/25/15 12:50 PM
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The Boston website offers a variety of educational materials and videos
for the specialty lens fitting practice. Bookmark fit-boston.com and
make it your “go to” resource for specialty GP lens information.
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© 2015 Bausch & Lomb Incorporated. Boston and Bausch + Lomb are trademarks of Bausch & Lomb or its affiliates. US/BNL/14/0012b
RCCL0515_BL Boston.indd 1
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Options Abound:
A 2015 REPORT on
V
isual freedom, better
quality of life and—
in many cases—improved quality of
vision are just some
of the benefits many wearers gain
from contact lenses as compared
to spectacles. With the ongoing
refinement of contact lens designs,
practitioners now have more options than ever to fit even the most
astigmatic presbyope or severe case
of dry eye. Technology has evolved
in tandem with the lenses themselves, offering more advanced lens
design and fabrication methods.
This article addresses how today there truly is a lens for every
patient.
SOFT LENSES
Lathe-cutting of custom soft toric
and soft toric multifocal lenses was
first introduced with the approval
by the Food and Drug Administration of the Definitive 74 silicone hydrogel lens material from
Contamac. This process results in
highly oxygen permeable lenses
in practically any lens parameter.
One relatively new example of this
design is the Intelliwave multifocal
toric (Art Optical), a center-near
simultaneous vision soft lens with a
multi-aspheric front surface for the
correction of vision at all distances.
This lens is an aberration-control
design that can be fit empirically.
The C-Vue Advanced HydraVue
toric multifocal (Unilens) is an-
22
other example. Replaced monthly,
it can be made in virtually any lens
parameter. Eye care practitioners
can also specify the base curve
radius, overall diameter, sphere
power, cylinder power and axis,
add power and zone size.
New innovations in custom soft
lens designs are not limited to the
astigmatic presbyopic patient.
Recently introduced custom soft
keratoconic designs such as the
KeraSoft IC (Bausch + Lomb) and
NovaKone (Alden Optical) offer a
made-to-order lens option available in almost every conceivable
power and cylinder axis. KeraSoft is available in the Definitive
silicone hydrogel material (Art
Optical) with aberration control
optics, while NovaKone uses a
54% hydrogel material. A quarterly replacement schedule is recommended for both lenses.
SCLERAL LENSES
Scleral lens use has continued to
increase in recent years as a result
of the high quality vision, lens stability and comfort they provide for
patients with irregular corneas and
dry eye. Although the original design has been available for decades,
new trends include the development of varying diameters, materials and back surface geometries.
There are several new designs of
note on the market. The Zenlens
(Alden Optical) is available in both
prolate and oblate designs with
either a 16mm or 17mm diameter.
With this lens, practitioners are
able to modify a single parameter
(i.e., base curve, limbal clearance
curve or peripheral curves) at a
time. Toric peripheral curves can
be ordered, as well as a front surface toric correction if needed.
The Europa Scleral (Visionary
Optics) is a second-generation
Jupiter scleral lens design with a
large optical zone, mid-peripheral
reverse curve and an enhanced
haptic profile for a better lensto-sclera fitting relationship. It is
indicated both for irregular cornea
correction and for patients with
ocular surface disease.
Tru-Form Optics has the DigiForm 15mm scleral lens which is
available in five primary designs
for patients with either keratoconic, LASIK, RK, post-corneal graft
or healthy corneas, as well as toric
and quadrant-specific versions.
The DigiForm 18mm diameter version incorporates laser markings
on the front surface corresponding to the fitting zone of the back
surface.
ABOUT THE AUTHOR
Dr. Bennett is a professor of
optometry and assistant
dean of student services
and alumni relations at the
University of Missouri-St.
Louis College of Optometry.
He is also the executive director
of the GP Lens Institute.
022_RCCL0915_F3.indd 22
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SPECIAL ISSUE:
CUSTOM LENSES
Keep abreast of new developments in lenses and
related technology that can strengthen your practice.
By Edward S. Bennett, OD
Fig. 1. Innovations in software are also improving our ability to fit
custom lenses. Here, an EyeSpace-created difference map of the Forge
orthokeratology design is used to successfully fit a 4.5D myopic patient.
Peripheral toricity is also an
important and increasingly popular
feature of the newer scleral lens designs. The Custom Stable Elite lens
(Valley Contax) is one such design.
Of course, scleral contact lenses
are not just for compromised eyes;
an increasing number have been
introduced for astigmatic and
presbyopic patients as well. These
include the Onefit P+A lens for
astigmatic patients and Reclaim
HD aspheric front surface multifocal for presbyopes, both from
Blanchard Contact Lens. The Elara
Scleral (Visionary Optics) is another example of a scleral lens with
a prolate design that has clinical
applications for both healthy eyes
and dry eye patients.
GAS PERMEABLE
MULTIFOCAL LENSES
The introduction of front surface
aspheric multifocal or asphericconcentric combination designs,
capable of providing high add
powers, has made GP multifocals
the “go-to” lenses for presbyopes interested in clearer vision.
The MPower lens (Art Optical),
a simultaneous vision multifocal design, uses anterior surface
eccentricity control to provide an
extreme power change generated
within the lens' central 5mm of the
lens.
New progressive segmented,
translating GP multifocal designs
have also been introduced as well
that allow not only uninterrupted
vision at distance and near but
also correction at all distances.
The SpectraVue by Tangent Streak
(Firestone Optics) multifocal lens
has the distance correction in
the upper section of the lens that
combines with a crescent-shaped
middle segment to provide a
progressive intermediate power
change, similar to a spectacle progressive addition lens but without a
limiting channel.
Several other relatively new GP
multifocal lens designs provide the
presbyope with vision correction at
all distances. These lenses complement other multifocal and translating designs introduced in recent
years, including the TriVA design
from ABB Optical and the Expert
Progressive lens (Essilor, Art Optical), both of which can be ordered
empirically based on refractive and
anatomical information.
HYBRID LENSES
Hybrid contact lens designs also
continue to improve. Problems
with first and second generation
designs include limited oxygen
transmission, tearing of the junction between the center GP and
soft skirt and a tight fitting relationship; more recent designs have
since addressed these issues.
One example, the UltraHealth
design (SynergEyes), uses a reverse geometry vault system to
accommodate a range of prolate
and oblate corneas. In this lens,
022_RCCL0915_F3.indd 23
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8/25/15 12:51 PM
OPTIONS ABOUND: A 2015 REPORT ON CUSTOM CONTACT LENSES
Fig. 2a. The EyePrintPro design exhibits the mold
accompanied by the resulting lens shape (in green).
the oxygen-permeable central GP
section is joined to the peripheral
silicone hydrogel skirt with a covalent bond to minimize tearing. A
second lens from the same company, the UltraHealth FC, is designed
specifically for oblate corneas,
including post-refractive surgery
patients and patients with pellucid
marginal degeneration. SynergEyes
is continuing to work on solving
the third issue.
CUSTOM TINTED LENSES
While tinted lenses are often considered cosmetic in nature, patients
with traumatic eye injuries or
congenital iris anomalies can also
benefit from these custom designs.
One company, Orion Vision, specializes in custom tinting of existing contact lenses supplied by ABB
Optical and Alden Optical.
MYOPIA PROGRESSION
While off-label, interest has risen
in the use of corneal reshaping
contact lenses to slow myopia
progression. Several studies on
24
Fig. 2b. A model of the lens on the eye.
young progressive myopes wearing
orthokeratology lenses overnight
indicated axial length growth was
significantly slowed in comparison
to those who wore contact lenses
and spectacles.1,2 Other research
evaluating peripheral plus power
soft lens designs found regular
wear resulted in an average of 50%
less myopia progression and a 58%
reduction in axial length progression, compared with non-peripheral plus power soft lens wearers.3
Peripheral plus bifocal designs have
also demonstrated an effect on
myopia, albeit less significant and
with some vision compromise.4-6
LENS DESIGN SOFTWARE
In addition to the lenses themselves, new software programs
are helping eye care practitioners achieve more successful fits.
Recently available in the US,
EyeSpace imports data from the
corneal topographer and uses this
information to design a rigid lens.
It has notable applications in designing specialty lenses. (Figure 1).
“I have been using EyeSpace
for a variety of corneal reshaping
patients,” says Michael Lipson,
OD. “It has worked well to attain
centration in some difficult cases.
Using it to design corneal reshaping lenses adds a high degree of
precision and control to the effect
and predictability to the process.”
The use of three-dimensional
mapping to help fit scleral lenses is
also gaining popularity, says Greg
DeNaeyer, OD. “Corneo-scleral
topography and 3D mapping
will significantly advance scleral
lens fitting. Rather than relying
on guesstimates from diagnostic
lenses, corneo-scleral topography
and scleral lens fitting software will
allow practitioners to virtually fit
scleral lenses that are customized
for each particular eye.”
The sMap3D corneo-scleral topography system (Precision Ocular
Metrology) is one such example
that uses a structured light approach to obtain micro precision
measurements of the cornea and
sclera.
022_RCCL0915_F3.indd 24
8/25/15 12:51 PM
Developed by Christine Sindt,
OD, and manufactured by AVT,
EyePrintPro is another 3D mapping
technology that creates a prosthetic
optical shell unique to the shape
of the patient’s eye (Figures 2a and
2b). “The EyePrintPro has given
me the opportunity to fit extremely
difficult patients with success,”
says Stephanie Woo, OD. “The
3D scanner used to create the lens
enables the practitioner to achieve
a near-perfect tear layer between
the cornea and the EyePrint, which
results in a precise fit and great
vision. You can also customize the
EyePrint to incorporate decentered
optics or prism within the lens,
which gives the patient a truly
unique and custom visual device.”
NO LIMITS
The introduction of innovative
new designs, supported by highly
advanced software and manufacturing technology, has resulted in
exciting new materials and designs
in practically any lens parameters
for almost any patient who is interested in contact lenses. This does
not mean that further research
is not warranted; rather, this is
simply the next step, and we look
forward to see what next year will
bring.
RCCL
The author wishes to acknowledge the following: Peg Achenbach,
OD (SynergEyes), Josh Adams
(Valley Contax), Greg DeNaeyer,
OD, Richard Dorer (Blanchard
Contact Lens), Cassandra Gordon
(Visionary Optics), Mike Johnson
(Art Optical), Michael Lipson,
OD, Kelly McKnight (Unilens),
Daren Nygren (Custom Craft Lens
Service), Keith Parker (AVT), John
Patterson (Orion Vision), David
1. Cho P, Cheung SW, Edwards M. The Longitudinal Orthokeratology Research in Children
(LORIC) in Hong Kong: A pilot study on refractive changes and myopic control. Curr Eye Res
2005;30:71-80.
2. Walline JJ, Jones LA, Sinnott LT. Corneal
reshaping and Myopia Progression. Br J Ophthalmol 2009;93:1181-1185.
3. Holden BA. The future of myopia management with contact lenses: Where to from here?
Possibilities and probabilities. Presented at the
Global Specialty Lens Symposium, January, 2015,
Las Vegas, NV.
4. Walline JJ, Greiner KL, McVey ME, Jones-Jordan LA. Multifocal contact lens myopia control.
Optom Vis Sci 2013;90:1207-1214.
5. Holden BA, Sankaridurg PR, de la Jara P, et al.
Decreasing peripheral hyperopia with distance
centre relatively plus powered periphery contact
lenses reduced the rate of progress of myopia: A
5 year Vision CRC study. E poster 6300, ARVO
2012.
6. Anstice NS, Phillips JR. Effect of dual focus
soft contact lens wear on axial myopia progression in children. Ophthalmology 2011;118(6):11521161.
SAVE THE DATE
s
ogie and
ol
N T
& T
ments
eat
Tr
w Tech
Ne
n
Chair: Paul Karpecki, OD
Speakers: Douglas Devries, OD; Jeff Gerson, OD;
Blair Lonsberry, OD
Rusch (Firestone Optics/Diversified
Ophthalmics), Ann Shackelford
(ABB Optical), Bill Shelly (Alden
Optical), Jan Svochak (Tru-Form
Optics), and Stephanie Woo, OD.
REVIEW OF OPTOMETRY
EDUCATIONAL MEETINGS OF CLINICAL EXCELLENCE
IN VISION CARE
2015
For More Information:
WWW.REVOPTOM.COM/PHILADELPHIA2015
SAN
DIEGO, CA PA
• APRIL
10-12
PHILADELPHIA,
• NOVEMBER
6-8
Credits
Administered by
Review of Optometry
022_RCCL0915_F3.indd 25
Up to
17 CE
(COPE approval pending)
Approval Pending
8/25/15 1:32 PM
1 CE
Credit
(COPE Approval
Pending)
CRITICAL MEASUREMENTS
TO IMPROVE
SCLERAL LENS
FITTING
Gathering as much data as possible can help
streamline the process and provide better outcomes.
By Jason Jedlicka, OD
S
cleral lenses have
always been a mainstay
of a specialty contact
lens practice, offering
patients with irregular
corneas and severe ocular surface
disease alike the chance to benefit
from lens wear. But the category
has been enjoying a renaissance
in recent years, as the evolution
of scleral lens designs has given
us more fitting options—namely,
standard and reverse geometry
designs, toric curves in the landing
and transition zones, and toric and
multifocal optics—that in turn allow us to offer these lenses beyond
the core group of traditional scleral
patients.
While this increase in scleral lens
parameter options gives practitioners the ability to fit a wider range
of eyes, it may make perfecting the
fit itself more challenging. Technology, on the other hand, is providing information that can help us
fit these lenses quicker and more
accurately.
This article reviews some of the
newer approaches to the evaluation
and fit.
26
THE LIMITS OF
DIAGNOSTIC SETS
Traditionally, scleral lenses are fit
using one or several diagnostic sets.
Practitioners use accompanying
fitting guides based on keratometry
readings, ocular surface health and
patient history to select an initial
diagnostic lens; alternatively, they
can simply choose a lens from the
middle of the set to start with and
adjust their selection accordingly
based on the amount of lens depth
needed. Some scleral lens fitters
may opt to look at the profile of
the eye they’re fitting and use their
experience to tell them which lens
is most appropriate.
These techniques, however, while
sometimes accurate, are difficult to
teach and unreliable overall. Keratometric readings provide little information about the ocular surface,
even when combined with ocular
history such as a diagnosis of keratoconus or surgical procedures. If
blind-selecting a lens, practitioners
face the issue of identifying the
necessary depth adjustments—assuming the fitting set is appropriate
for the eye shape to begin with.
Thus, a more appropriate measurement system is needed.
SELECTING A LENS
While scleral lenses, unlike corneal
lenses, vault the cornea to rest on
the sclera, it is still vital for the
practitioner to understand the
contours of the patient’s cornea to
ensure adequate but not excessive
vault, which, after allowing for
lens settling, should be approximately 150µm to 250µm centrally
and then and taper back to eventually land on the sclera just past the
limbus. Inadequate vault can result
in cornea/lens touch and associated
problems, as well as difficulty with
lens removal due to capillary attraction; excessive vault can inhibit
oxygen flow, patient comfort and
ease of application. Aligning a
scleral lens properly also lessens
ABOUT THE AUTHOR
Dr. Jedlicka is a clinical assistant professor at the Illinois
College of Optometry and
president of the Scleral Lens
Education Society.
034_RCCL0915_F4_CE.indd 26
8/25/15 12:52 PM
SPECIAL ISSUE:
CUSTOM LENSES
Fig. 1. Corneal topography display
demonstrating a corneal diameter
of 12.19mm, confirmed by manual
measurement of 12.2mm.
the need for high prescriptions that
may reduce visual acuity, which
can occur especially when fitting
steep corneal lenses in keratoconus,
for example. Corneal topography
can be used to ascertain corneal
diameter or horizontal visible iris
diameter (HVID), corneal apex
location and the sagittal height of
the cornea at a 10mm chord.
Anterior segment depth measurements obtained using optical
coherence tomography (OCT) or
Scheimpflug imaging is another
way to improve the fit of a scleral
lens. The initial fitting process
can be streamlined by use of
OCT or Scheimflug imaging, as
these instruments obtain objective
measurements of the depth of the
cornea and sclera out to nearly
15mm, thereby providing a known
starting point for diagnostic fitting.
In addition, these images allow the
fitter to see the contour of the cornea and sclera, to help determine if
a particular fitting set may be more
ideal than others. OCT can also be
used to evaluate the success of a fit
at follow up by providing precise
measurements of the tear reservoir
and edge contour to the sclera after
a period of wear, without having
to remove or manipulate the lens
on eye.
the apex of the cornea is located
Other scleral imaging instruoutside the central 4mm, however,
ments provide information regardor if there are significant elevations
ing scleral shape and toricity to
determine whether a lens should be (e.g., Salzmann’s nodular degeneraordered with toricity in the landing tion) near the peripheral cornea, a
reverse geometry lens design may
zone. Below are some methods for
be more successful (Figure 3).
obtaining these measurements.
• Sagittal Height. Another useful
• HVID. Because the scleral lens
measurement to aid in the scleral
needs to vault the entire corlens fitting process is corneal sagitnea and limbus, it must be large
enough in diameter to land outside tal height. Found on many corneal
topographers, it is the measurethe corneal-limbal zone. Corneal
ment between the geometric center
diameter measurements can be
of the cornea and the intersection
obtained using a corneal topograof a specified chord length—in
pher—simply capture the topothis case, 10mm (Figure 4). Avergraphical map and use the corneal
age sagittal height from 10mm to
diameter measure on the display
(Figure 1). Some topographers may also offer the
ability to measure HVID
with a point and click line
display. A handheld ruler
(Figure 2), slit lamp reticule or slit lamp camera
with measuring capabilities, as well as anterior
segment OCT, can also be
used to measure HVID.
• Corneal Shape.
Evaluating corneal shape
is a good next step in the
scleral lens fitting process.
Knowing where the corneal apex is will allow you
to choose a lens with the
most appropriate shape to
match the cornea. If the
corneal apex is within the
central 4mm of the cornea,
a standard geometry
Fig. 2. HVID ruler for measuring horizontal
corneal diameter.
lens should work well; if
licensing board to see if this counts toward
your CE requirements for relicensure.
Release Date: September 2015
Expiration Date: September 1, 2018
Goal Statement: This course reviews methods for capturing and interpreting essential
measurements when fitting scleral lenses.
Faculty/Editorial Board:
Jason Jedlicka, OD, and Greg DeNaeyer, OD
Credit Statement: COPE approval for 1 hour
of continuing education credit is pending
for this course. Check with your state
Joint-Sponsorship Statement: This
continuing education course is jointsponsored by the Pennsylvania College of
Optometry.
Disclosure Statement: Dr. Jedlicka has
no finanical interest in any products mentioned. Dr. DeNaeyer is a shareholer of
Precision Ocular Metrology and received
royalty payments for the Europa lens.
27
8/25/15 12:52 PM
CRITICAL MEASUREMENTS TO IMPROVE SCLERAL FITTING
Fig. 3. Corneal topography
demonstrating the apex of the
cornea located approximately 4.5mm
inferior to the corneal center. This
shape may be better fit with a scleral
lens with a reverse geometry design.
15mm for all eye types is approximately 2,000µm.1 Thus, by using
the 10mm chord depth and adding
2,000µm for the sag of the 10mm
to 15mm chord plus the desired
vault, you can come very close to
the proper sag of the lens needed.
Take the following example: a
10mm chord demonstrates a sagittal height of 1,906µm. Based on a
desired initial vault of 350µm centrally, a diagnostic lens in a 15mm
diameter should be 4,256µm (i.e.,
1906µm + 2,000µm + 350µm for
vault = 4,256µm starting point for
a 15mm lens). If the lens to be fit
is larger than 15mm, the sagittal
Fig. 4. Three-dimensional display of corneal topography shows corneal sagittal
height measurement at 10.0mm of 1,906 microns.
Fig. 5. OCT image demonstrating a sagittal height of 3,760 microns at a 15mm
chord.
Fig. 6. Pentacam image demonstrating a sagittal height of 4,230 microns at a
chord of 14.64mm.
28
height will need to be increased
incrementally, as the larger area
of eye surface to be covered will
mean greater overall depth. In my
experience, having reviewed several
scleral fits in retrospect, I find that
an adjustment of approximately
300µm per millimeter of lens diameter is fairly accurate (i.e., 4,256µm
+ 600µm, for a 2mm diameter
increase = 4,856µm sagittal height
for a 17mm diameter lens).
Obtaining a cross-sectional image of the anterior segment using
diagnostic imaging technology is
another useful way to obtain a
starting point for an initial diagnostic lens. The software included
in these instruments can provide
measurements for a variety of possible heights and widths (Figures
5 & 6), simplifying the initial lens
selection process.
• Scleral Contour Measurements. Some instruments are
capable of evaluating the shape
of the sclera, which may help
practitioners achieve a proper lens
fit. Figure 7 shows an image of a
highly toric sclera obtained from
the Eye Surface Profile (Eaglet
Eye), one of two such instruments
(the other being the sMap3D by
Precision Ocular Metrology; see
“Virtually Fitting Custom Scleral
Lenses,” p. 29). However, while
these instruments provide more information about the ocular surface
than corneal topography, at this
time they are so new that the data
they provide cannot yet be applied
universally to all scleral lenses with
simple formulas or rules.
ASSESSING LENS FIT
Once the scleral lens is on the
eye, OCT can be used to assess
lens fit by providing information
on central vault, limbal clearance
and landing zone in relation to
the sclera. The amount of desired
8/25/15 12:52 PM
Virtually Fitting
Custom Scleral Lenses
By Gregory W. DeNaeyer, OD
The sMap3D topographer
(Precision Ocular Metrology)
uses a structured light approach for three-dimensional
mapping to obtain measureFig. 1. Data from three eye positions is stitched together to form a 3D model.
ments of the cornea and
sclera with a 22mm maximum
ments and over all sagittal depth value, which
field of view. The sMap3D takes multiple trianare used for custom fitting.
gulated measurements using a single DLP proThe sMapPro software gives sagittal depth
jector and two cameras positioned laterally on
data at any specified chord. Corneo-scleral toeach side. Fluorescein is added to the patient’s
pography and elevation maps can be evaluateye, which is necessary for imaging the corneal
ed. Scleral toricity can also be calculated from
and bulbar conjunctival surface. The patient
any specified radius from center (Figure 2). The
is then instructed to gaze at a fixated light
virtual fit screen allows the practitioner to send
straight ahead while the eyelids are opened
the data directly to Visionary Optics for analyas widely as possible with assistance from the
sis and design of a custom Europa Scleral lens.
practitioner or a staff member. The practitioner
A diagnostic lens does need to be applied for
focuses the eye and captures the image. Two
over-refraction to determine final lens power.
additional measurements with the patient fixating up and down are taken in succession.
The sMapPro software is able to stitch
together the images taken in straight, up, and
down positions to produce a three-dimensional
model of the patient’s eye (Figure 1). Stitching
is a necessary step to obtain maximum area of
the sclera that is occluded by the lids despite
the eyelids being held open. A stitched model
is required for measurement of the vertical meFIg. 3. Virtual fit scleral lens on a keratoconus patient.
ridians to determine accurate toricity measure-
Fig. 2. Scleral elevation map and toricity.
Alternatively, the practitioner can custom
fit the lens using the software’s virtual fitting
plots. sMapPro software allows for complete
specification of any lens parameter to virtually
adjust for corneal and limbal clearance, as well
as custom back surface toricity. The sMapPro
recommends a starting base curve based upon
any desired initial amount of central corneal
clearance. Peripheral curve toricity is calculated
based upon the patient’s maximum scleral
toricity. The fitting software adjusts peripheral
curve widths to ensure limbal clearance. Figure
3 shows a virtual fit of a Europa scleral lens for
a patient with keratoconus.
Dr. DeNaeyer is clinical director of Arena Eye
Surgeons in Columbus, Ohio, and a consultant
to Alcon, Visionary Optics, Bausch + Lomb and
Aciont. He is also the designer of the Europa
scleral lens (Visionary Optics) and a shareholder
for Precision Ocular Metrology (sMap3D).
29
8/25/15 12:52 PM
CRITICAL MEASUREMENTS TO IMPROVE SCLERAL FITTING
Fig. 7. Corneal and scleral topography
obtained with an eye surface profiler
indicate a highly toric scleral contour.
may have more
significant longterm effects on
the ocular surface. OCT can be
particularly helpful
in comparing edge
fit along different
meridians in helping to determine
if toric landing
curves might be
Fig. 8. OCT images of an adequately vaulted scleral lens helpful to improve
(top) and inadequately vaulted scleral lens (bottom).
a scleral lens fit.
Figure 10 shows
clearance over the limbal area.
several edge profiles.
Fitting scleral lenses in the past
OCT imaging can also be used
has been more of an art than a scito evaluate edge profiles. This is
helpful in ensuring that the landing ence in many respects. The future
of scleral lens fitting figures to be
zone of the lens is acceptable in all
quadrants. A scleral lens that is too more scientific, driven by precise
ocular surface measurements and
flat will demonstrate edge lift on
software that can customize a lens
OCT. This flat edge will encourage debris to accumulate under the to the individual eye. In the immediate term, using the technology
lens and fogging of the vision over
the course of the day. A scleral lens that is available will streamline the
fitting process while we wait for a
that is too tight will demonstrate
technological revolution in scleral
an appearance of lens “digging in”
to the conjunctival-scleral complex. lens fitting to occur.
This tightness will create discom1. Kojima, R. Eye shape and scleral lenses. Contact Lens Spectrum. April 1, 2013.
fort and redness over time, and
central vault and limbal clearance
varies somewhat from one lens design to another, as well as from one
fitter to the next. Generally speaking, a settled scleral lens should
have between 150µm and 250µm
of central vault, which tapers down
to a fraction of that (20µm to
40µm) over the limbus to eventually land on the sclera. A scleral lens
with excessive or inadequate vault,
or one that lands on or inside the
limbus, needs to be reordered with
the appropriate adjustments made
to fix these deficiencies. Keep in
mind these parameters may change
somewhat from initial application to a time several
hours later as the scleral
lens settles into the tissue.
With respect to limbal
clearance, there is no
“magic number”; rather,
as long as some amount
of clearance exists, the
limbus should be able to
tolerate the lens. Note,
however, excessive limbal
clearance may allow for
conjunctival prolapse and
possibly sectoral hypoxia
due to a thick tear reservoir. Figure 9 demFig. 9. OCT images of scleral lenses
onstrates several OCT
over the limbus, demonstrating ideal,
images of scleral lenses
inadequate and possible excessive
clearance.
with varying degrees of
30
RCCL
Fig. 10. OCT images of scleral edge profiles.
The top image appears to have a proper
alignment to the sclera, the middle image is
loose and the bottom image is tight.
8/25/15 12:52 PM
CE TEST ~ SEPTEMBER 2015
EXAMINATION ANSWER SHEET
Critical Measurements to Improve Scleral Lens Fitting
1. Which modern diagnostic lens selection method was uncommon 10 years ago?
a. Using Ks and the fitting guide.
b. Starting in the middle of the fitting set.
c. Using OCT to measure corneal sagittal height.
d. Using direct observation of the corneal shape.
2. Which of the following statements is true?
a. Use of technology (i.e., OCT, corneal topography, scleral profilometry) is of little
value when fitting scleral lenses.
b. Corneal topography can provide good information when fitting scleral
lenses, even though the lens does not touch the cornea.
c. OCT can tell us much about the shape of the sclera.
d. Scleral topographers have been around for many years, but they have never
been useful when fitting scleral lenses.
Valid for credit through September 1, 2018
Online: This exam can also be taken online at www.reviewofcontactlenses.com.
Upon passing the exam, you can view your results immediately. You can also
view your test history at any time from the website.
Directions: Select one answer for each question in the exam and completely
darken the appropriate circle. A minimum score of 70% is required to earn credit.
Mail to: Jobson Optometric CE, Canal Street Station, PO Box 488 New York, NY 10013
Payment: Remit $20 with this exam. Make check payable to Jobson Medical
Information LLC.
Credit: COPE approval for 1 hour of CE credit is pending for this course.
Sponsorship: Joint-sponsored by the Pennsylvania College of Optometry
Processing: There is an eight-to-10 week processing time for this exam.
3. Horizontal visible iris diameter (HVID) can be measured by all of the
following except:
a. Calipometery.
b. A handheld HVID ruler.
c. Keratograph 5 M topographer.
d. Slit lamp reticule.
4. Which of the following is least influential when using a reverse geometry fitting set?
a. Pellucid marginal degeneration.
b. Salzmann’s nodular degeneration with peripheral lesions.
c. Keratoconus with an apex within the central 3mm of the cornea.
d. Radial keratometry scars.
5.
a.
b.
c.
Which of the following statements about the cornea is false?
Sagittal height at 10mm is useful in determining an initial diagnostic lens.
Sagittal height at 10mm is easily obtained from a corneal topographer.
Sagittal height at 10mm is noticeably different for normal corneas versus keratoconus.
d. Sagittal height at 10mm provides an estimate of the shape of the sclera.
Answers to CE exam:
A
B
C
1.
A
B
C
2.
A
B
C
3.
A
B
C
4.
A
B
C
5.
6.
7.
8.
9.
10.
D
D
D
D
D
A
B
C
D
A
B
C
D
A
B
C
D
A
B
C
D
A
B
C
D
Evaluation questions (1 = Excellent, 2 = Very Good, 3 = Good, 4 = Fair, 5 = Poor)
Rate the effectiveness of how well the activity:
1
2
3
4
5
11. Met the goal statement:
12. Related to your practice needs:
1
2
3
4
5
13. Will help improve patient care:
1
2
3
4
5
1
2
3
4
5
14. Avoided commercial bias/influence:
15. How do you rate the overall quality of the material? 1
2
3
4
5
16. Your knowledge of the subject increased: Greatly
Somewhat
Little
17. The difficulty of the course was:
Complex
Appropriate Basic
18. How long did it take to complete this course? _________________________
6.
a.
b.
c.
d.
OCTs are useful when fitting scleral lenses in all of the following except:
Measuring central vault.
Measuring limbal clearance.
Measuring lens power.
Evaulating the lens edge–sclera relationship.
7. Which of the following statements is true?
a. Scleral contour measurements help us to know when to use a toric haptic.
b. Scleral topographers provide information about scleral shape but not the
cornea.
c. Scleral topographers are fully compatible with nearly all scleral lens designs
and have software built-in for lens design for most manufacturers.
d. Scleral topography contour measurements tell us much about the ability to
obtain good tear exchange with a scleral lens.
8. Which of the following critical measurements for scleral lens fitting is least
available to practitioners at this time?
a. Corneal topographical shape.
b. Corneal sagittal height at 10 mm.
c. Scleral contour measurements.
d. HVID measurement.
9.
a.
b.
c.
d.
Why is the shape of the cornea useful information when fitting a scleral lens?
It tells you whether toric landing curves are needed.
It tells you whether you need a lens that is standard or reverse geometry.
It tells you whether the scleral lens is likely to make the corneal disease progress.
It tells you whether you have enough vault with your initial diagnostic lens.
10. Which of the following is not a benefit of using technology (i.e., OCT,
corneal topography, scleral profilometry) to assist with fitting scleral lenses?
a. It instills patient confidence in the provider and the process.
b. It allows technical support staff to help in the process.
c. It allows you to auto-fit scleral lens designs using built-in software.
d. It allows you to obtain objective readings of lens fit at follow up for better
monitoring.
19. Comments on this course: _________________________________________
___________________________________________________________________
20. Suggested topics for future CE articles: ______________________________
___________________________________________________________________
Identifying information (please print clearly):
First Name
Last Name
Email
The following is your:
Home Address
Business Address
Business Name
Address
City
State
ZIP
Telephone #
-
-
Fax #
-
-
By submitting this answer sheet, I certify that I have read the lesson in its entirety
and completed the self-assessment exam personally based on the material presented. I have not obtained the answers to this exam by fraudulent or improper means.
Signature: ________________________________________ Date: _____________
Please retain a copy for your records.
LESSON 111768, RO-RCCL-0915
31
8/25/15 12:53 PM
The GP Expert
By Stephanie L. Woo, OD
A Lens for Every Eye:
Successfully fitting hard-to-fit eyes is key to growing your specialty lens practice.
C
LOYALTY PROGRAM
With any contact lenses—standard,
toric or even multifocal—the key
to a successful fit is achieving the
best vision, comfort and ocular
health response possible for the
patient. Doing so effectively builds
patient loyalty, especially when
developing a contact lens specialty
practice. Candidates for custom
soft lenses include those who are
experiencing refraction, rotation
or fit issues in their current lenses
due to corneal irregularity, particularly high astigmatism, and GP
32
lens candidates who are concerned
about experiencing discomfort in
hard lenses. Astigmatic presbyopes
are also well suited to wear custom
soft lenses.
If the patient expresses dissatisfaction with the vision or comfort
provided by their current lenses,
try explaining that a customized
lens may be more comfortable
and provide better vision. When a
patient sees you for their comprehensive eye exam, and you have
performed a careful refraction
along with keratometry readings,
this could lead you to recommending custom lenses.
Photo: Matt Kauffman, OD
ustom contact lens
design is a constantly
evolving field, from
the advent of GP
lenses in 1978 to more
recent developments in orthokeratology. Soft lenses in particular
now feature expanded diameters,
curvatures, thicknesses and sphere
and cylinder powers, giving practitioners more options than ever to
manage complicated prescriptions
in a highly precise way. Expanded
diameters enable practitioners to
fit both small and large corneas
of patients who would otherwise
drop out of contact lens wear due
to comfort or fit issues; base curve
customization can also help with
achieving great fit. Powers for these
lenses range from +/-50D, giving
even the most nearsighted patients
the ability to see. With contact
lenses this versatile, we can expand
the amount of patients that we can
help to wear contacts.
Fig. 1. TruForm’s QuadraCone.
Take this scenario, for example:
“Jane, I see why your vision is not
as sharp with your current contacts. The lenses you are wearing
now are a ‘one-size-fits all,’ meaning that the shape of the lens only
comes in one curve. Thus, you may
need another shape to fit your eye
properly. Also, your current lenses
only correct most of your prescription, not all of it. A more custom
lens may fit your eye better and
give you better vision.” Adjusting the prescription and selecting
a custom lens better suited to the
patient’s unique corneal shape are
two simple ways to earn patient
loyalty.
Even if they have not previously
worn contacts, most patients with
high astigmatism are aware their
prescription is high—in fact, they
may have already been told they
are not candidates for contact lens
wear. So, present the possibility of
wearing custom lenses instead: “I
think you are a great candidate for
contact lenses; however, you have
a significant amount of astigmatism. It is more than most standard
contact lenses have available. So,
I would recommend a custom lens
that corrects your entire prescription and fits your eye properly.”
Once patients understand why they
can’t wear standard contact lenses,
yet they are very motivated to wear
them, they have no problem trying
a more custom design.
SUPPLY AND DEMAND
Many contact lens manufacturers
use some sort of fitting nomogram to design a lens. Typically,
the patient’s keratometry values,
refraction and horizontal visible
iris diameter (HVID) are used to
create a lens; however, if the HVID
is not available, most laboratories
can still create the lens.
HVID has become somewhat
of a hot topic within the contact
lens community, as about 26% of
patients fall out of the average iris
diameter range.2 Appropriate lens
diameter is important for lens stabilization and centration; thus, an
032_RCCL0915_gpe.indd 32
8/25/15 12:51 PM
Go
Further—
Without
Leaving
Home
Clinical Pearls
• Custom soft lenses provide excellent vision and fit.
• Ordering custom soft lenses is simple—many
manufacturers only require refraction and keratometry
values.
• The cost is often comparable to or even less than the
patient’s current lenses.
• Most patients cannot be fit anywhere but in your office,
ensuring patient loyalty.
Photo: Tony Caporall, OD
tics), which features different quadrants that can be
manipulated to be steeper
or flatter, depending on the
patient’s needs. Keratoconic lenses sometimes have
a bit too much edge lift,
which can cause the lens to
decenter and dislodge from
the eye. Steepening one
of the quadrants can help
Fig. 2. Scleral lens with front toric markings
and notch near pinguecula.
tuck the edge in for a more
precise fit (Figure 1).
inappropriate lens diameter can
Scleral lenses have also imlead to excessive lens movement
proved significantly in a relaand discomfort, and subsequent
tively small amount of time. Most
patient dropout. This is due to the manufacturers have a multifocal
pressure of the lid-lens interaction, scleral design available for the
which causes the lens to move and presbyopic population. Some
sclerals are also available in a
rotate on the eye; increasing the
front surface toric version, aldiameter of the lens decreases the
lowing residual astigmatism to
lid-lens interaction. Most custom
be easily added into the prescriplenses can be ordered through
tion (Figure 2). Practitioners can
the manufacturer’s website, or by
also rely on notching, a popular
supplying the laboratory with the
method of maneuvering around
patients’ refraction and keratomconjunctival obstacles such as pinetry values directly.
gueculas and blebs, and corneal
topographic mapping, to fit sclerCUSTOM GP LENSES
als more efficiently.
Soft lenses are not the only lenses
that are improving: huge strides
1. Nichols J. Contact Lens Update 2012. Contact
are being made in the GP lens inLens Spectrum. Jan 2012.
dustry as well. One such example
2. Davis R, Eiden B. Problem solving toric conis the QuadraKone (TruForm Op- tact lenses. Contact Lens Spectrum. Feb 2013.
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own home.
Review offers nearly
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away. Our extensive
library of exams
runs the gamut from
keratoconus to fundus
autofluorescence, and
everything in between.
RCCL
www.revoptom.com/
continuing_education
032_RCCL0915_gpe.indd 33
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Out of the Box
By Gary Gerber, OD
Blinded by the Light?
Just because something works once doesn’t mean that it always will, or that it could
never be surpassed by something even better.
M
any of us have
read or heard
practice management advice that
goes something
like this: “If you want your patients to do X, tell them Y.” For
example, “If you want to have
more patients purchase annual
supplies of contact lenses, tell them
the price is less per box if they buy
eight boxes than if they buy only
one.”
Sounds reasonable, doesn’t it?
So, after hearing this suggestion,
you return to your practice and
mention it to your next patient.
And either it works or it doesn’t.
In either case—success or failure—
the question becomes, what do
you do next? Does this one result
give you enough information from
which to craft a new strategy?
How much can you extrapolate
from a single data point? Not
much. No scientist would attempt
to draw conclusions from a study
with a sample size of n=1. But in
business matters, we have a harder
time seeing the shortcomings of
such an approach.
If the patient responded the way
you had hoped and agreed to the
bulk purchase, a few factors will
help you determine if this approach is worth continuing or not.
First, will your patient have a better or worse clinical outcome with
a year’s supply of lenses on hand?
Studies suggest that it will generally be more favorable because patient compliance is typically higher
when they have more lenses at the
ready. However, is that going to be
the case for this particular pa-
34
tient, or will they be one of those
outliers who hoard their lenses?
Since this remains a possibility,
if you choose to use this strategy your definition of “success”
should include a system of checks
and balances so that when lens
hoarders return, you don’t make
the same mistake.
Next—and in my view most
importantly—make sure that
viewing this as a successful strategy and thus worthy of routine
use, doesn’t close the door to
other strategies that may be
even better. For example, what
would happen if you presented
the lenses to the patient and said,
STAY FLEXIBLE
The answers to these practice
management questions will vary
between different practices, and
even between staff members in a
single practice. There isn’t a single
right or wrong answer—rather, in
any case it is important simply to
ask yourself, “What will we do
if this works, and can we make it
even better?”
Regardless of your plan of action, however, be wary of using
industry benchmarks as your
goals. This will help you avoid any
potential issues with using varying
definitions. Continuing with the
same example, one doctor might
ASK YOURSELF, “WHAT
WILL WE DO IF THIS
WORKS, AND CAN WE
MAKE IT EVEN BETTER?”
“When you buy a year’s supply of lenses, you will never run
out,” but you never mentioned
the discount? Do you think as
many patients would take you
up on your offer? Even if only
10% fewer did, what would the
effect be on the increased revenue
you’d generate by not offering
a discount? Alternatively, don’t
assume that the lack of a volume
discount will lead to fewer sales.
It can (and often does) lead to
more, depending on how you
present the situation.
report that 10% of their patients
purchase annual supplies, while
a second doctor reports 90% of
their patients do so. What is not
recorded, however, is the fact that
the first doctor has a large base of
specialty scleral patients and the
second has a significant population of millennials who buy their
lenses directly from the practice’s
website. Additionally, keep in
mind that benchmarking typically
demonstrates averages and reports
of “what is,” not what could be—
as such, they can be limiting.
RCCL
034_RCCL0915_otb.indd 34
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6/30/15 11:33 AM
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