PDF Edition - Review of Optometry

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RCCL
REVIEW OF CORNEA
& CONTACT LENSES
FEBRUARY 2016
SOLUTIONS AND LENS CARE
Lens Care Lessons P. 8
Artificial Tear Makeup P. 22
Pairing Solutions and GPs P. 38
REALITY CHECK:
HOW
SOLUTIONS TESTING
FALLS SHORT
Outdated FDA protocols don’t account for real-world usage, newer lens materials
and virulent organisms. Proposed updates could bring big changes.
EARN 2 CE CREDITS. P. 28
Supplement to
topography-guided gp fitting • dextenza on deck • marketing new lens options
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contents
Review of Cornea & Contact Lenses | February 2016
departments
4
News Review
Lipid-binding Differences Noted;
Corneal Diameter Affects
Postoperative Astigmatism
6
My Perspective
This Year, Strive to Avoid Stress
By Joseph P. Shovlin, OD
8
Practice Progress
Solution Savers
By Mile Brujic, OD, and
Jason R. Miller, OD, MBA
10
Corneal Consult
features
12
18
Putting it On the Map:
Fitting Rigid Lenses Using
Corneal Topography
Familiarizing yourself with corneal mapping
can lead to more success with your contact
lens patients.
By Vivian Phan Shibayama, OD
Forward Thinking:
Where Can New Lenses
Lead Your Practice?
From sclerals to daily disposables and tinted
lenses, new designs can add to your practice
if you’re willing to change your mindset.
By Jane Cole, Contributing Editor
The Case of the Finicky Fungus
By J. James Thimons, OD
38
The GP Experts
Good Chemistry
By Robert Ensley, OD, and
Heidi Miller, OD
40
Pharma Science & Practice
Dextenza on Deck
By Elyse L. Chaglasian, OD, and
Tammy Than, MS, OD
42
Out of the Box
What’s In a Name?
By Gary Gerber, OD
22
28
Artificial Tears:
Looking Beneath the Surface
These seemingly simple drops are more
complex than you think. Do you know what’s
in them?
By Mike Christensen, OD, PhD,
and Tressa Larson, OD
CE — Reality Check:
How FDA Testing Falls Short
Outdated FDA protocols don’t account for real-world usage, newer lens materials and virulent organisms. Proposed updates could bring big changes.
By Yvonne Tzu-Ying Wu, PhD, MPH, An Truong,
B.Optom, and Fiona Stapleton, PhD
Cover design by Ashley Schmouder
©iStock.com/Jobsonhealthcare
/ReviewofCorneaAndContactLenses
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REVIEW OF CORNEA & CONTACT LENSES | FEBRUARY 2016
3
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News Review
IN BRIEF
■ Researchers from the University
of Missouri School of Medicine have
identified a link between administration of the varicella zoster virus
vaccine for chickenpox and shingles
and presentation of keratitis.1 Though
the potential for corneal inflammation
as a side effect of the vaccine is low,
primary care physicians should inform
all patients prior to administration, the
researchers say.
1. Fraunfelder RW. Varicella zoster vaccine-associated keratitis. Paper presented at American
Academy of Ophthalmology, Nov. 16, 2015; Las
Vegas, NV.
■ Consider reinforcing orthokeratology education, particularly for male
patients, reports a study in the January
2016 issue of Eye & Contact Lens.1 Researchers in southern Taiwan identified
a total of 86 microbial strains from
38 culture-positive specimens taken
from orthokeratology lens case fluids
of 41 pediatric wearers. Interestingly,
frequently reported pathogens (i.e.,
Serratia marcescens, Pseudomonas
aeruginosa and Staphyloccocus aureus) in contact-lens related microbial
keratitis were identified less commonly
in this study; additionally, the lens cases of male subjects exhibited a higher
microbial bioburden than those of
female subjects.
1. Lo J, Kuo M, Chien C, et al. Microbial bioburden
of orthokeratology contact lens care system. Eye
& Contact Lens. 2016 Jan;42(1):61-7.
■ A comparison of femtosecond
laser-assisted LASIK and small-incision lenticule extraction (SMILE),
published in the February 2016 issue
of Cornea, suggests both procedures
achieve similar good visual outcomes
in the correction of myopia and myopic astigmatism; however, patients who
underwent SMILE exhibited a lower
induction rate of spherical aberration
six months postoperatively, suggesting
long-term outcomes of the procedure
may ultimately be more beneficial.1
However, further research is needed
based on a larger sample size to confirm this.
1. Liu M, Chen Y, Wang D, et al. Clinical outcomes
after SMILE and femtosecond laser-assisted
LASIK for myopia and myopic astigmatism: a prospective randomized comparative study. Cornea.
2016 Feb;35(2):210-6.
■ Menicon America has announced
FDA approval for its LacriPure
non-preserved saline for rinsing both
soft and rigid lenses. Packaged in 5ml
unit-dose vials, the saline is also approved as a first-of-its-kind scleral lens
insertion solution as an alternative to
irrigation saline, according to Menicon.
4
Lipid-binding Differences Noted
D
eposition of cholesterol
on contact lenses varies
significantly between lens
materials, reports a study
in the January 2016 Optometry and
Vision Science.1 Though silicone
hydrogel (SH) materials are known
to increase oxygen transport to the
ocular surface, certain chemical
components within these materials
may also negatively impact wettability (and potentially patient comfort)
if exposed to very high levels of
lipids.2-4 To date, however, no study
has investigated the degree to which
daily disposable lenses uptake lipids—in particular, cholesterol.
Researchers at the University of
Waterloo in Canada incubated three
SH materials and four conventional hydrogel (CH) materials in an
artificial tear solution containing
radioactive C-labeled cholesterol.
Each was submerged for two, six,
12 and 16 hours to simulate typical
daily disposable lens wear times.
Results indicated both contact
lens type and length of incubation
were factors in the amount of cholesterol deposition. No significant
difference in the amount deposited
on the SH materials was observed;
a difference did exist among the
CH materials. Overall, however, SH
materials deposited more cholesterol
than CH materials.
These results suggest a number of
things, the authors say. First, daily
disposable patients who exhibit relatively heavy levels of lipids in their
tears due to factors such as meibomian gland dysfunction may benefit
from certain CH lens types, such as
nelfilcon A and etafilcon A materials. Additionally, wearers who
require higher oxygen transport but
exhibit oily tears should be aware
of potential wetting issues when
wearing SH daily disposable lenses.
However, the researchers point out
that further study is needed to determine if the lipid profiles in question
are in fact detrimental to lens wear,
given their very low levels.
Other caveats: this study only
considered one lipid type, cholesterol (many others are found in the
tear film); the deposition of certain
lipids could be beneficial to lens
wear (as previously reported by the
same group); and the amount of
lipid deposited may not be as important as whether the lipids under
investigation are oxidized or remain
in their natural state.5
RCCL
1. Walther H, Subbarman L, Jones LW. In vitro cholesterol deposition on daily disposable contact lens
materials. Optom Vis Sci. 2016 Jan;93(1):36-41.
2. Jones L, Subbarman LN, Rogers R, Dumbleton K.
Surface treatment, wetting and modulus of silicone
hydrogels. Optician. 2006;232:28-34.
3. Maldonado-Codina C, Morgan PB. In vitro water
wettability of silicone hydrogel contact lenses determined using the sessile drop and captive bubble
techniques. J Biomed Mater Res A. 2007;83:496502.
4. Read ML, Morgan PB, Kelly JM. Maldonado-Codina
C. Dynamic contact angle analysis of silicone hydrogel contact lenses. J Biomater Appl. 2011:26:85-99.
5. Lorentz H, Rogers R Jones L. The impact of lipid
on contact angle wettability. Optom Vis Sci. 2007;
84;10: 946-53.
SPEED Questionnaire Vetted
The Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire is comparable to
the Ocular Surface Disease Index (OSDI) questionnaire for separating asymptomatic and
symptomatic dry eye patients, reports a study published in the February 2016 issue of
Cornea.1 Investigators compared the answers of 657 undergraduate students at the University of Cape Coast in Ghana, determining the internal consistencies of the OSDI and
SPEED questionnaires to be approximately the same (i.e., 0.897 and 0.895, respectively).
However, the SPEED questionnaire was relatively better in terms of internal consistency
compared with the OSDI questionnaire, indicating it is a valid measure for dry eye and
could be used in epidemiological studies and clinical practice, the researchers say.
1. Asiedu K, Kyei S, Mensah SN, et al. Ocular surface disease index (OSDI) versus the standard patient evaluation
of eye dryness (SPEED): a study of a nonclinical sample. Cornea. 2016 Feb;35(2):175-80.
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RCCL
REVIEW OF CORNEA
& CONTACT LENSES
11 Campus Blvd., Suite 100
Newtown Square, PA 19073
Telephone (610) 492-1000
Fax (610) 492-1049
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EDITORIAL STAFF
EDITOR-IN-CHIEF
Jack Persico [email protected]
SENIOR ASSOCIATE EDITOR
Aliza Becker [email protected]
CLINICAL EDITOR
Joseph P. Shovlin, OD, [email protected]
ASSOCIATE CLINICAL EDITOR
Christine W. Sindt, OD, [email protected]
EXECUTIVE EDITOR
Arthur B. Epstein, OD, [email protected]
CONSULTING EDITOR
Milton M. Hom, OD, [email protected]
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GRAPHIC DESIGNER
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EDITORIAL REVIEW BOARD
Mark B. Abelson, MD
James V. Aquavella, MD
Edward S. Bennett, OD
Aaron Bronner, OD
Brian Chou, OD
Kenneth Daniels, OD
S. Barry Eiden, OD
Desmond Fonn, Dip Optom M Optom
Gary Gerber, OD
Robert M. Grohe, OD
Susan Gromacki, OD
Patricia Keech, OD
Bruce Koffler, MD
Pete Kollbaum, OD, PhD
Jeffrey Charles Krohn, OD
Kenneth A. Lebow, OD
Jerry Legerton, OD
Kelly Nichols, OD
Robert Ryan, OD
Jack Schaeffer, OD
Charles B. Slonim, MD
Kirk Smick, OD
Mary Jo Stiegemeier, OD
Loretta B. Szczotka, OD
Michael A. Ward, FCLSA
Barry M. Weiner, OD
Barry Weissman, OD
Corneal Diameter Affects
Postoperative Astigmatism
C
orneal diameter should
be determined prior to
cataract surgery, as it can
lead to varying degrees of
corneal astigmatism depending on
the type of incision used, reports
a study in the January 2016 issue
of Cornea.1 Other factors already
known to impact postoperative
astigmatism include incision size,
configuration and location relative to the limbus, as well as the
axis on which the main incision is
performed.
Researchers observed cataract
procedures performed on 330
eyes at the General Hospital of
Piraeus “Tzaneio” Attiki in Greece
from February 2011 to October
2013. Patients were divided into
four groups according to corneal
horizontal diameter, i.e., whiteto-white (WTW) distance: group
A ≤ 11.6mm; group B 11.7mm
to 11.9mm; group C 12.0mm to
12.2mm; and group D ≥ 12.3mm.
At the first postoperative month,
surgically-induced astigmatism
(SIA) was 0.98D ± 0.6SD in group
A, 0.79D ± 0.43SD in group B,
0.68D ± 0.45SD in group C and
0.53D ± 0.32SD in group D, while
at six months postoperatively, SIA
was 0.77D ± 0.43SD in group A,
0.69D ± 0.34SD in group B, 0.62D
± 0.36SD in group C and 0.49D ±
0.27SD in group D.
These data indicate that a change
greater than 0.5D in corneal
astigmatic power at the first and
sixth months postoperatively was
significantly lower in eyes with
WTW distance 12.0mm to 12.2mm
and ≥ 12.3mm, compared with eyes
with WTW distance ≤ 11.6mm and
11.7mm to 11.9mm. In effect, the
researchers note, the smaller the
cornea, the larger the effect on the
power of postoperative astigmatism.
“These findings are important
because it identifies an additional
perioperative variable that is helpful
in improving astigmatic results
following cataract surgery,” Eric
Donnenfeld, MD, a surgeon on
Long Island, says.
Researchers also classified the
participating eyes into groups of
either right or left to evaluate if
superior and superomedial incisions
in the left eyes lead to greater SIA
due to the primary incision being
situated closer to the optical center
of the cornea and the placement of
the phaco probe against the nose
and brow. They also examined
whether superior and superolateral
incisions produce more postoperative astigmatism in against-the-rule
astigmatic eyes than in with-the-rule
eyes.
Ultimately, however, results indicated no differences in SIA between
right and left eyes, and the type of
astigmatism could not be accounted for, due to the unvaried patient
base. The results are further limited
by the evaluation of anterior surface
topography, the researchers note.
Research that includes posterior
corneal effects is needed to more
fully evaluate astigmatism-induced
results.
RCCL
1. Theodoulidou S, Asproudis I, Kalogeropoulos C, et
al. Corneal diameter as a factor influencing corneal
astigmatism after cataract surgery. Cornea. 2016
Jan;35(1):132-6.
Advertiser Index
Alcon ....................................Cover 3
CooperVision ....... Cover 2, Page 7
Menicon .............................. Cover 4
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My Perspective
By Joseph P. Shovlin, OD
This Year, Strive to Avoid Stress
If you are like most of us, decreasing tension in 2016 is a laudable New Year’s resolution.
M
any of us in practice—especially
for 10 years or
more— know all
too well how stress
can lead to some amount of
professional “burnout.” It has a
pervasive effect on nearly every
action we perform daily, from
the degree of care we provide our
patients to our relationships with
friends, family and coworkers.
Symptoms of burnout include
mental and physical exhaustion,
stress, depersonalization (i.e.,
cynicism and sarcasm) and a reduced sense of accomplishment.1-6
While burnout is common in
most industries, it’s on the rise
among health care professionals
in particular.2
A recent Mayo Clinic study assessing the incidence of burnout
symptoms, such as work/life imbalance, depression and suicidal
ideation among physicians found
that 54.4% of those surveyed
reported one or more symptoms
of burnout in 2014, compared
with 45.5% in 2011 (p=0.001).4
With respect to individual
symptoms, the rate of physicians
with a healthy work/life balance
decreased in the three-year span
measured, with only 40.9% of
practitioners reporting they had
sufficient time for personal and
family life in 2014.2,3 Long-term
consequences linked to burnout included: (1) lower patient
satisfaction and quality of care;
(2) higher medical error rates and
risk for malpractice; (3) higher
physician and staff turnover; (4)
physician alcohol and drug abuse;
and (5) physician suicide.4,5
6
LOW BATTERY
What is causing this epidemic?
Mark Linzer, MD, offers a list of
specific drivers below:5
• Stress. Research has demonstrated you’re 15 times more likely
to burn out if you operate under
constant stress. Ongoing concern
for medical errors and potential
malpractice cases also raises stress
levels; additionally, payers may obstruct tests that you deem necessary,
limiting your ability to provide the
best patient care possible.
• Chaos. Caring for patients is
what keeps most doctors motivated,
but caring for too many of them
under a stressful environment is generally what burns them out. Recent
changes imposed by government
entities and payers have further
heightened the demand.
• Discord. Motivation wanes
quickly if your practice ideals and
values don’t match, or if a healthy
camaraderie does not exist between
members of your practice.
• Depersonalization. We often serve as the emotional buffer
between the patient and our own
environment, sometimes limiting
our ability to connect with them.
And, after years of practice, things
can begin to seem mundane or
depersonalized.
• Interference. Leaving insufficient
room for personal schedule changes
and needs in daily life can lead to
negative spillover into work life, and
vice-versa.
• Neglect. Self-care is critical—
when you neglect yourself, you
neglect your patients. Taking time to
relax to ensure you can focus when
needed and provide the best care
possible.
PHYSICIAN, HEAL THYSELF
Let’s face it—work is stressful.
Indeed, that’s why they call it work.
But the difference between manageable levels of stress and complete
professional burnout is the ability
to recover when not working.6
Personal downtime is key, and we
all need an activity that brings us
joy. It is vital that we carve out some
time from our workweek to do the
things we love.
Research has shown prevention
and treatment measures for burnout should be approached both on
the personal and organizational
level.6 Personal burnout prevention measures involve maintaining
self-awareness, appreciative inquiry,
narrative medicine and maintaining a healthy work/life balance.5,6
Measures that can be taken at the
organizational level include the
creation of specific programs to support health care providers and the
allowance for flexible work hours.
R
emember, we have a lot to
bring to the battle against
burnout: intelligence, good incomes,
support from family and friends
and life outside of health care and
an overall investment in education
and self-growth.6 None of us are immune to burnout—make avoiding it
your resolution for 2016.
RCCL
1. Drummond D. Physician burnout-the three symptoms, three phases, and three cures. The Happy MD.
2015 Oct.
2. Swift D. Physician burnout climbs 10% in 3 years,
hits 55%. Medscape; 2015 Dec.
3. Peckham C: Physician burnout: It just keeps
getting worse. Medscape; Jan, 2015.
4. Drummond D. Physician burnout: Its origin,
symptoms and five main causes. Family Practice
Management, 2015 Sept/Oct;(5):42-7.
5. Linzer M. How to beat burnout: 7 signs physicians
should know. AMA Wire. 2015 Mar.
6. Drummond D. Physician burnout: Why it’s not a
fair fight. The Happy MD. 2015 Sept.
p06_RCCL0216_MP.indd 6
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centration, stable fit and excellent visual acuity you and your patients can depend on.
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Improves centration and stability by reducing lens rotation;
simplifies the fitting process and provides better visual acuity.
2
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Increases the area devoted to stability and a comfortable fit.
3
Smooth, continuous surface
Maximizes wearer comfort and adds to stability.
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©2014 CooperVision, Inc.
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Practice Progress
By Mile Brujic, OD, and Jason Miller, OD, MBA
Solution Savers
Lens care can make or break the contact lens experience for patients.
Here’s how to tip the odds in favor of success.
E
ven as we recognize that
the newest contact lens
development efforts
give us viable options
for everyone, including our most difficult patients, it
is important to remember most
lenses prescribed today in North
America continue to be two-week
and monthly disposables, despite
the influx of daily replacement
options. How, as eye care practitioners, can we help patients
choose the right solution, and how
does this help our goal of practice
building? Reminding patients—
both old and new—of proper
contact lens care and solution use
is key to maintaining a healthy patient population and even drawing
in new ones.
A tremendous amount of research documents widespread lack
of contact lens compliance, which
can significantly affect the patient’s
wearing experience.1-3 Although
poor hygiene during lens care
and handling typically dominates
discussions of noncompliance,
inattention to lens/solution compatibility when purchasing care
products is also a concern among
practitioners.
Patients face the challenge of
selecting the right solution for their
lenses following the initial fitting
appointment, especially as many
multipurpose solutions created
decades ago remain packaged
similarly to even the most recently
engineered products. Intentional
mimicry in product design by generic or store-brand products can
mislead patients into making poor
choices at the drugstore.
8
KNOW YOUR SOLUTIONS
Biotrue (Bausch + Lomb), OptiFree
PureMoist (Alcon) and Revitalens
OcuTec (Abbot Medical Optics)
are three of the latest additions to
the multipurpose solution options.
Biotrue contains hyaluronic acid,
a glycosaminoglycan that temporarily binds to the surface of the
lens to increase daily comfort.5
OptiFree PureMoist contains the
copolymer polyoxyethylene-polyoxybutylene under the trade name
HydraGlyde, which is said to improve lens surface wettability and
end-of-day comfort.6,7 Revitalens
OcuTec contains the wetting agent
Tetronic 904 in attempts to optimize surface moisture.8
Other disinfection options come
in the form of hydrogen peroxide
systems—most notably ClearCare
(Alcon), the newer ClearCare Plus
(Alcon) and PerioxiClear (Bausch +
Lomb). Overall, peroxide systems
have remained the mainstay for
individuals with multipurpose
solution sensitivities due to the
lack of chemical preservatives in
the peroxide. For those individuals
prone to developing giant papillary
conjunctivitis (GPC) who may
not be good candidates for daily
disposable contact lenses, hydrogen peroxide disinfection works remarkably well as a solution option
after the patient’s GPC has been
appropriately managed (Figure 1).
And in fact, peroxide systems are
having a bit of a renaissance lately,
as practitioners see them as a
possible bulwark against noncompliance. Patients can’t “top off”
their solution if using peroxide, for
instance.
ClearCare is a one-step peroxide
system that combines disinfection
and storage capabilities into a
single entity. Patients can either
rub and rinse the lenses with this
solution and then place them in the
lens case cage prior to submerging
them in the solution, or place the
lenses in the cage, rinse them for
five seconds and then submerge the
entire entity. An overnight soak
in ClearCare requires six hours of
neutralization prior to lens wear.
Alcon recently added HydraGlyde
to its ClearCare formulation under
the name ClearCare Plus.
PeroxiClear, another one-step
peroxide disinfection solution, has
a four-hour soak requirement for
neutralization. This time frame
may be better suited for contact
lens wearers with less consistent
schedules who may require a faster
cleaning method. Disinfection
occurs via a platinum-modulating
compound known as carbamide:
when the platinum disc is submerged in peroxide, the carbamide
binds to the platinum to inhibit
the neutralization rate. This keeps
the peroxide at a higher concentration than normal (i.e., when
not in the presence of carbamide),
and increases the total exposure of
the lenses to the peroxide.9 During
the first 60 minutes of soaking,
the carbamide loses its affinity
for the platinum disc, causing the
platinum disc to rapidly neutralize
the peroxide in the system. This
rapid neutralization is what allows
wearers to remove the lens from
the peroxide solution after only a
four-hour soak and comfortably
place it on the eye.
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UNDERSTAND
THEIR
DIFFERENCES
New technologies
can help create better
wearing experiences
for the patient—which
is why practitioners
must remain cognizant of the number of
store-brand peroxide
systems that are also
available. While similar at first to some of
the branded systems,
they, in fact, have
significant differences
that can irrevocably alter a patient’s wearing
FIg. 1. Patients with giant papillary conjunctivitis may benefit from switching to a
experience.
peroxide system.
A number of struc3. Dumbleton KA, Woods CA, Jones LW, Fonn D.
tural differences exist between
delays placement of their lenses
The relationship between compliance with lens
branded peroxide basket-and-disc
into the basket, the lenses’ toreplacement and contact lens-related problems
in silicone hydrogel wearers. Cont Lens Anterior
systems and generic formulations.
tal exposure time to peroxide is
Eye. 2011 Oct;34(5):216-22.
In non-branded peroxide soludecreased—effectively lowering
4. Morgan PB, Woods CA, Tranoudis IG, et al.
tions, the platinum disc is typically disinfection efficacy. Should the
International Contact Lens Prescribing in 2014.
Contact Lens Spectrum. 2015 Jan;30:28-33.
located at the bottom of the vial
patient insist on using private
5. Scheuer CA, Fridman KM, Barniak VL, et al.
that holds the peroxide rather than label peroxide systems, let them
Retention of conditioning agent hyaluronan on
hydrogel contact lenses. Cont Lens Anterior Eye.
attached to the basket that conknow that that the lenses and lens
2010 Dec;33 Suppl 1:S2-6.
tains the lenses. While a seemingly basket should be submerged into
6. Senchyna M, Stauffer P, Davis J, et al. Chartrivial detail, this difference can
the peroxide immediately after the acterization of a multi-purpose lens solution
designed for silicone hydrogel materials. IOVS.
affect the neutralization profile of
peroxide has been placed in the
2010 Apr;51(13):3426.
the peroxide: because the platinum vial containing the platinum disc.
7. Napier L, Garofalo R, Lemp J, et al. Clinical
disc is attached to the basket conevaluation of an investigational multi-purpose
disinfecting solution. Poster presented at:
taining the lenses, both the lenses
iving a little extra attention
Contact Lens Association of Ophthalmologists
and platinum disc are submerged
to contact lens care guidance
meeting, Sept. 2010, Las Vegas.
8. González-Méijome JM, da Silva AC, Faria-Rimeans healthier, and thus happier,
into the peroxide simultaneously
beiro M, et al. Multi-site clinical assessment of
patients—and happier patients
to provide maximum exposure
Complete Revitalens MPDS in 2981 contact lens
wearers across Europe and USA. Cont Lens Antemeans more referrals.
of the lenses to the peroxide. In
rior Eye. 2013 Dec;36(6):289-93.
contrast, the placement of the
1. Tilia D, Lazon de la Jara P, Zhu H, et al. The ef9. Millard KA, Hook D, Hoteling A, Wygladacz K.
platinum disc at the bottom of the
fect of compliance on contact lens case contamiA one-step hydrogen peroxide-based contact
lens solution. Contact Lens Spectrum. Special
vial in store-brand products means nation. Optom Vis Sci. 2014 Mar;91(3):262-71.
Edition 2014.
2. Kuzman T, Kutija MB, Juri J, et al. Lens wearers
that the neutralization process
10. Contact Lens Research Services. Andrasko
non-compliance - is there an association with
begins as soon as the peroxide is
Corneal Staining Grid. Available at: www.staininglens case contamination? Cont Lens Anterior Eye.
grid.com. Accessed November 20, 2015.
2014 Apr;37(2):99-105.
placed in the vial. If a lens wearer
G
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Corneal Consult
By J. James Thimons, OD
The Case of the Finicky Fungus
Treating with antibacterial drugs can be tempting when presented with acute infection,
but first make sure the agent matches the organism.
A
68-year-old
Caucasian female
contact lens wearer
presented for an
emergency evaluation on a Sunday evening with a
complaint of severe pain in one
eye. Her history was significant for
an eight-day treatment of that eye
with topical Vigamox (moxifloxacin, Alcon) QID and an unspecified
steroid drop BID. According to the
patient, she initially responded well
to the aforementioned treatment,
but had since developed a case of
intense ocular pain and mild vision
loss over the past 24 to 48 hours.
A physical examination revealed
the right eye to have normal visual
acuity at 20/20- with correction.
The left eye with correction was
20/50, pinholing to 20/25-. An external exam revealed a notable area
of conjunctival inflammation and
hyperemia located in the inferior
nasal sector. The remainder of the
conjunctiva was relatively clear.
An anterior chamber reaction was
present, but less than 1+, and the
globe demonstrated a remarkable
tenderness to touch when palpated
through the lid, with the patient
indicating pain when the lid was
retracted for slit lamp assessment.
The cornea displayed a well-defined
2.5mm epithelial defect with no
associated infiltration or thinning of
the tissue. No purulent activity was
detected, and defect margins were
soft, but well defined.
A dilated examination using
tropicamide and homatropine
showed no evidence of vitreous
cells, and the homatropine provided
relief of the pain.
The patient was advised of
possible etiologies and alternate
treatment options, as the lesion
had shown no improvement
after a week of therapy. Scrapings
from the patient were cultured on
chocolate, blood, thioglycolate and
Sabouraud’s media and plated on
slides. These were delivered to the
laboratory for assessment of cellular
constitution, as well as resistance
and sensitivity. Because of the eight
days of prior treatment, expectations for growth were relatively
limited; however, I asked that the
plates be kept by the laboratory
for further evaluation of atypical
organisms—specifically, Nocardia,
atypical Mycobacterium and other
fungi that require an extended
growth opportunity to demonstrate
their presence.
With regards to the current
presentation, potential factors of
note included an insufficient dosing
regimen, given that current therapy
was being administered QID with
no significant effect. The possibility that the organism was resistant
to Vigamox was also considered;
thus, the question was whether to
maintain the current agent, add
an additional therapeutic item and
change the dosage, or switch to a
more aggressive therapeutic regimen. Given the late hour of the day
and the limited pharmacy options
available at that time, I elected to
increase the Vigamox to Q2h and
add Neosporin ointment TID to the
affected eye to increase gram-positive bacterial coverage until fortified
agents became available if needed.
I also elected to discontinue the
steroid that was being administered
BID, given the lack of positive
response, and add homatropine 5%
TID in light of its effect on pain.
THE TWIST
Two days after the aforementioned
change in therapy, no notable
improvement in the course or
symptoms was observed, though
the margins of the lesion appeared
slightly softer than previously noted.
A trace infiltrate was also apparent
below the epithelial defect with no
thinning observed. Additionally, the
anterior chamber showed trace cell.
In light of the relative status quo of
the presentation, I elected to continue the recently instituted therapeutic
course, but watch the patient carefully. The patient was scheduled for
another follow-up exam two days
hence, but contacted the office late
the following day to advise that the
eye had become markedly worse in
the last 12 hours, with an increase
in redness and discomfort, and a
decrease in vision clarity.
Clinical assessment that evening
revealed a lesion with minimal
increase in the stromal infiltration in
the anterior stromal bed immediately below the lesion. The margin of
the lesion appeared improved and
well-circumscribed, and the tissue
was not soft or pliable as before;
however, the anterior chamber
showed an increase to 1-2+ reaction, with no hypopyon. No
significant stromal haze was present
outside the area of defect. The globe
itself was 3-4+ hyperemic, with an
intense zone of ciliary flush.
At that point, I advised the patient that because of the duration of
treatment without visible success, I
10 REVIEW OF CORNEA & CONTACT LENSES | FEBRUARY 2016
p10_RCCL0216_CC.indd 10
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was becoming concerned that this
was not a typical bacterial infection, and that the lack of resolution
warranted a change in therapeutic
intention. I placed the patient on
vancomycin Q1hr alternating with
Vigamox Q1hr, and discontinued
the Neosporin. The patient was
atropinized in the office, and then
subsequently scripted for atropine
on a once-daily basis, given the significant decrease in her discomfort
level as a result of the relaxation of
the ciliary spasm.
The laboratory was contacted
that evening for culture evaluation; no growth was reported. The
patient was seen 36 hours after
initiation of the additional vancomycin therapy and reported that the
eye felt mildly improved. Clinical
assessment showed no change in
the lesion, although there was a
notable decrease in the inflammatory response of the anterior chamber
secondary to the use of the atropine.
In the case of lesions of this
duration without notable response,
the possibility of a viral or other non-bacterial etiology must
be considered, though given the
appearance of this lesion and the
lack of relative neurotrophia on
examination, this was unlikely. That
being said, the patient was placed
on 500mg valcyclovir TID PO and
asked to return in two days. At
subsequent visits over the following
week, the patient showed no notable change. The vancomycin and
Vigamox were reduced to QID as a
result of the lack of response, and
the patient was maintained on oral
antiviral therapy. The atropine was
decreased to once every other day.
A NEW
HOPE
At this point,
discussions
with respect
to the lack of
efficacy of any
of the interventions, as well
as the lack of
progression of
the lesion and
the absence
of a positive
laboratory
outcome from
A minimal ulcer and slight stromal involvement
the cultures,
characterized this patient’s presentation.
led to the decision for a second opinion.
returned to almost 20/20 without
Due to the lack of response to
correction. The anterior chamber
a traditional therapeutic regimen,
was quiet at the last visit, and the
even though the lesion was without lesion was completely resolved.
satellite involvement and minimal
to any infiltrative change or necrone interesting aspect of this
sis, the next step was to institute a
case: this patient was an
topical antifungal agent.
avid gardener and, despite the late
The patient was placed on Q2h
phase of the season in the north,
natamycin therapy with maintefungus is not typical; however, the
nance of topical Vigamox QID and
decision to discontinue the steroid
the oral antiviral, and discontinuand obtain a true picture of the
ation of the vancomycin. The labdisease state was the key point. In
oratory again reported no growth;
this case, the net change in status
ironically, however, the patient
was mild, unlike other fungal cases
showed improvement in the first
I have managed where discontinu24 hours on the natamycin. By the
ation resulted in rapid progression
third day, the lesion had improved
of the disease state. Having treated
dramatically. It was at this time
one of the first patients in the
that laboratory results indicated a
United States during the Fusarium
Fusarium infection.
outbreak several years ago, I
The natamycin was maintained
requested that the patient bring
with an antibiotic to provide proher contact lenses, lens case and
phylaxis against infection from an
solution to the office to forward to
opportunistic agent while the eye
the laboratory for assessment. As
was compromised by the fungus.
of four weeks later, no growth had
The patient’s acuity ultimately
been identified.
O
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FITTING RIGID LENSES USING
CORNEAL TOPOGRAPHY
Familiarizing
yourself with
corneal mapping
can lead to more
success with your
GP contact lens
patients.
By Vivian Phan
Shibayama, OD
A
lthough the manual
keratometer has served
eye doctors well for over
150 years, the advent
of corneal topography
has revolutionized our ability
to discern corneal shape
characteristics, as topographers
have largely replaced the
keratometer as the essential
component in the contact
lens fitting process. Allowing
practitioners to see beyond the
3mm limit of the keratometer, a
corneal topographer also gives us
the ability to analyze the cornea in
three dimensions when assessing
shape characteristics.
Especially now that the technology is equipped to provide
more information about the cornea
than just the central curvature
readings, we must consider how
best to use these maps to benefit
our contact lens practice. For
example, proper analysis of the
map can help us select a more
accurate initial lens, determine
lens type and assist in making the
proper adjustments to the lens fit.
This article will cover the
different types of corneal
topography maps and how to use
this information to fit corneal
rigid gas permeable (GP) and
scleral lenses.
TYPES OF TOPOGRAPHY
There are two methods of recording corneal topography: reflection-based and projection-based.
Reflection-based topography—the
most widely used—is further
divided into raster photogrammetry and placido-based topography. Raster photogrammetry
reads curvature by taking multiple
triangulated measurements using
a projector and two cameras.
Currently, this relatively new technology is being used to measure
scleral curvature for scleral lens
fitting. Placido-based topographers, in contrast, use multiple
concentric rings reflected off the
corneal surface to analyze corneal
curvature using slope; the height
of the cornea is extrapolated from
these measurements. This method
is dependent on the quality of the
reflection, so images are sometimes
ABOUT THE AUTHOR
Dr. Shibayama recently
completed a one-year
specialty contact lens
fellowship at the Jules Stein
Eye Institute following
graduation from the
Pennsylvania College of
Optometry, before taking
over the specialty lens practice
from her mentor, Barry Weissman, OD.
Her practice consists of 80% specialty
fits, including keratoconus, post-corneal
transplants, scars, dry eyes, post-refractive
ectasia and infantile aphakia.
p12_RCCL0216_F1 Topography.indd 12
1/27/16 12:16 PM
TYPES OF
different elevations on the cornea
TOPOGRAPHY
are measured from an average
MAPS
reference point. Areas higher than
• Axial Map.
the reference will appear red and
This displays
yellow, while the lower areas will
the rate of local
appear green or blue. It is importcurvature change
ant to combine data from both the
of the anterior
axial map and elevation map while
surface, based
fitting contact lenses.
Fig. 1. Poor image capture from a patient with ocular
surface disease.
on the placido
While the axial map will demonimage. Curvature
strate the curvature of the eye,
measurements are the elevation map will provide
made between
more detailed information with
the placido rings.
regards to the unique shape of the
Light is assumed
cornea—the steepest point of the
to be refracted
cornea is not necessarily the most
from the corneal
elevated.
surface, using
• Tangential or Instantaneous
the optical center
Map. This is the most sensitive
as the reference
map for determining changes in
Fig. 2. Scheimpflug image from Pentacam.
points; as such,
curvature in the peripheral region
the map is more
of the cornea. These maps include
sensitive to changes in central
difficult to capture if the cornea is
peripheral curvature in the calcucurvature versus in the periphery.2
badly distorted, as in the case of
lations for scaled curvature and
advanced ocular surface disease
don’t use a central reference point.2
Axial maps are particularly useful
1
(Figure 1).
for determining the meridian, regu- It is particularly useful when fitting
Projection- or elevation-based
larity and amount of astigmatism.
corneas that have curvature changtopography measures the anterior
• Elevation Map. The most
es in the periphery, as in post-reand posterior corneal surface by
valuable map for corneal GP
fractive surgery patients (Figure
both reflection and light profitting, the elevation map appears
3).2 Tangential maps can also help
jection through the cornea. The
most similar to the contact lens
determine the exact shape and size
Orbscan (Technolas) uses optical
fluorescein pattern. In this display,
of the cone in keratoconus.3
slit-scan imaging and the Pentacam
(Oculus) uses rotating Scheimpflug
imaging to acquire data (Figure 2).
Projection-based topography measures height and specific points on
the cornea. From height, the slope
and radius of curvature is measured, making these measurements
more precise than reflection-based
topography. In addition, projection-based topography does not
rely on the quality of the reflection
from the cornea and can read bad- Fig. 3. Comparison of axial and tangential maps on a post-refractive patient.
Readings of center curvature are the same, but vary greatly in the periphery.
ly distorted corneal surfaces.1
13
1/27/16 12:16 PM
FITTING RIGID LENSES USING CORNEAL TOPOGRAPHY
the posterior corCorneas with a higher rate of
nea is assumed to
flattening may benefit from aspherremain uncorrect- ic designs. The term eccentricity
value (E value) describes the rate
ed by placement
of flattening in the cornea (Figure
of a contact lens
5). Normal corneas exhibit an
on the anterior
E value of approximately 0.55.5
surface, thus
Higher than average E values indiaffecting the pacate a prolate cornea that flattens
tient’s final visual
at a more rapid rate, such as in
acuity (Figure 4).
keratoconus.
Posterior elevaCorneal alignment of the GP
tion topographic
maps may be able lens in the midperiphery can be
managed by increasing or decreasto provide practitioners with better ing the E value of the GP according to the E value on the topogratarget visual
phy.6 In normal corneas, contact
acuity for conFig. 4. A keratoconus patient showing a posterior
lenses with normal eccentricity
tact lens fitting.
elevation of 104μm and GP corrected BVA of 20/30.
values can decenter on patients
Within
the
visual
Notice the focal elevation of the central cone on the
with higher than average E values.
axis, for patients
elevation map vs. the broad area of steepening on
the axial map. The tangential map will show the most
In an irregular cornea, such as in
with a posterior
accurate size and curvature of the cone.
a keratoconus patient, the midelevation between
70µm and 100µm, periphery is usually significantly
PROJECTION-BASED MAPS
flatter than the apex. Increasing
a practitioner should expect no
• Anterior Float. After calculatthe E value in both cases will assist
better than 20/30 acuity; between
ing a best-fit sphere for the ante130µm and 140µm, no better than in the alignment of the lens withrior corneal surface, the anterior
out sacrificing the alignment of the
20/40 acuity; and greater than
float demonstrates elevation above >200µm, no better than 20/70
central fit.6
and below this hypothetical plane,
When fitting a toric cornea,
acuity.
with warm colors present above
an axial topography map can be
the sphere and cool colors present
used to visualize the nature of
GP FITTING
below it. This map is useful in
The primary goal of GP fitting is to the astigmatism (i.e., how regular
assessing the regularity of astigma- respect the shape of the cornea as
or irregular it is and how far it
tism and areas of asymmetry, and
much as possible without inflicting extends throughout the cornea).
is similar to the axial map.3
This information can help the
damage or changes on the ocular
practitioner make decisions about
• Posterior Float. A display of
surface. In the case of a normal
diameter and the peripheral fit of
the elevation above and below a
cornea, it is not always necessary
the lens.
best-fit sphere for the posterior cor- to use corneal topography to
nea surface is used here similarly
design lenses;
as in the anterior float. Acquiring
however, peripha map of the posterior surface has
eral corneal data
become the gold standard in ruling can be valuable
out the presence of forme fruste
in determining
keratoconus in patients during
what type of lens
LASIK consultations.3 Changes in
to choose for
the patient’s epithelial basement
your patients.
membrane and Bowman’s layer
This data is espeare the first histological changes in
cially important
keratoconus.4 Traditionally, only
if the practithe anterior surface of the cornea
tioner decides
is evaluated when fitting a contact
to fit a larger
Fig. 5. Indices: eccentricity, pupil diameter, horizontal
lens; as such, any irregularity of
diameter.
visible iris diameter.
1/27/16 12:16 PM
Fig. 6. Topography over multifocal GP showing line of sight centered on the
right (fit on K) and decentered up on the left (fit flat).
Photo: Christine W. Sindt, OD
KERATOCONUS
In keratoconus, the key to lens
selection is to determine the size,
shape and location of the cone. To
do this, again, compare the axial,
tangential and elevation maps. The
axial map will show the overall
shape and curvature of the eye,
while the elevation map will show
the shape of the cone.
Tangential maps can help the
practitioner measure the size and
shape of the cone, which can be
helpful in determining overall
diameter as well as optic zone
size (Figure 4). Tangential maps
may also provide more accurate
curvature information about the
periphery of the cornea to aid the
practitioner in designing peripheral
curves for the patient.
Small diameter lenses are best
for the nipple form of keratoconus—in which the cone is located
centrally, steeply curved and typically less than
5mm in diameter—while large
diameter lenses
are preferable
for decentered
cones, which are
displaced from
the apical center
into the inferior Fig. 7. A patient with PMD. The tangential map shows
quadrant. Large steepening inferior to what is displayed in the axial map.
diameter lenses
are also best
for oval cones,
which typically
measure more
than 5mm in
diameter and are
characterized by
a broad area of
Fig. 8. Comparison of theoretical Medmont software
fluorescein pattern compared to real diagnostic lens.
elevation in the
In multifocal lens fitting, new
theories in multifocal design have
emphasized the importance of the
centration of multifocal optics in
order for the fit to be successful.
The topographer can be used
to obtain an objective measurement of pupillary size to assist
in optic zone design (Figure 5).
Topography can also be used to
check multifocal optics alignment
through the patient’s line of sight
while the patient is wearing the
lens (Figure 6).7
Some topographers come
equipped with software programs
that can assist virtually with contact lens fitting. Brand name lenses
as well as generic lens parameters
are preloaded into these programs
for the practitioner to choose
from. These programs allow the
practitioner to select a lens and
will simulate the fluorescein pattern of the lens using the patient’s
corneal map. The practitioner can
then adjust the lens parameters
and see the changes in the fluorescein pattern.8
inferior cornea, as they provide
forced centration over the pupil.
Reverse geometry lenses can also
be helpful for centration with a
secondary curve steeper than the
central base curve to accommodate
the decentered cone without excessive central vault.
Pellucid marginal degeneration
(PMD) is typically characterized by
the presence of a “kissing doves”
pattern on the axial map (Figure
7), which represents the thinning
that occurs 1mm to 2mm away
from the limbus. Once a diagnosis
of PMD is confirmed, the elevation
map should be referenced to find
the location and elevation of the
cone.
Traditional keratoconic lenses do
not fit patients with PMD; instead,
these patients should be fit with
large diameter reverse geometry
lenses or scleral lenses to accommodate the steepness in the mid
periphery.1 Once the diameter and
lens design is determined, the next
step is to select the base curve.
There are many opinions on the
best way to choose the initial lens
for your patient, from selecting the
15
1/27/16 12:16 PM
FITTING RIGID LENSES USING CORNEAL TOPOGRAPHY
lens based on the yellow curvature on the axial map to fitting
0.2 flatter to average K reading
and selecting the reference sphere
from the elevation map. The best
suggestion is to follow the method
of the fitting guide of the lens that
is being used.1
POST-GRAFT FITTING
There are many factors to consider
when choosing the right type of
lens for a patient who has undergone corneal grafting. The physiologic needs of the donor cornea
must be respected, reducing mechanical and hypoxic stress to the
cornea and the risk of neovascularization and rejection. Generally,
contact lenses don’t cause graft
rejection; however complications
from contact lens wear can.10,11
Gas permeable lenses in general offer the best visual correction, and
corneal GPs specifically have the
best oxygen transmission. Corneal
GPs should be considered first
with fitting post graft patients.10
Approximately 20% of patients
who undergo PKP still have irregular astigmatism and benefit from
GP correction.12
When selecting an initial diagnostic lens, compare the axial and
elevation maps to determine the
shape of the graft. Larger diameter
GP lenses (i.e., 10.5mm to 12mm)
are best suited to cover the graft/
host junction of most grafts, while
keratoconic designs fit optimally
over prolate grafts (31% of grafts),
which are steeper in the center and
flatter in the periphery. Oblate or
plateau-shaped corneas (31% of
grafts) typically benefit best in a
reverse geometry design that is
flatter in the center with a steeper
secondary curve (Figure 9). In the
case of a mixed prolate/oblate cornea with symmetrical astigmatism
(18% of grafts), use the axial map
to determine how regular the astigmatism is and how far it extends
throughout the graft.
Fig. 9. Oblate graft.
Fig. 10. Graft with regular astigmatism.
Fig. 11. Image from sMap3D from
Visionary Optics.
Bitoric or back surface toric
designs are best suited for corneas
with symmetrical astigmatism, as
they distribute the weight of the
lens as evenly as possible (Figure
10). This lens can be fit much like
a traditional bitoric, using the
axial map curvature readings to
align the flat base curve to the flat
meridian. Add only two-thirds
of the total toricity to the steep
meridian—it is safer to add less
toricity than is believed necessary
to encourage lens rock and tear
exchange.13 A bitoric lens that is
too tight can result in mechanical
trauma to the graft.
Grafts with asymmetrical astigmatism account for 9% of grafts.
These corneas are most successful
in large diameter spherical lenses,
which mask the irregular astigmatism. Thirteen percent of grafts are
tilted (i.e., transitioning from steep
to flat). Tilted grafts are considered by many practitioners to be
the most difficult to fit, and often
require a large diameter GP lens
or scleral lens.12
SCLERAL LENSES
Similar to keratoconic lens designs, each scleral lens fitting set
will recommend its own method
of choosing an initial diagnostic
1/27/16 12:16 PM
Fig. 12. Steep, prolate graft.
lens. Practitioners may be directed
either to begin by selecting the
middle lens in the set or using the
patient’s sagittal height, horizontal visible iris diameter or a
trial-and-error method to find the
right lens. Since these lenses are fit
predominantly based on sagittal
height, keratometric readings don’t
typically provide enough information to tell us which lens would
fit the patient best; instead, these
readings give information on the
pathology and general shape of the
cornea to help us determine if we
need to fit the lens flat (for post-refractive cornea) or steep (for keratoconus). However, topography
systems do offer more information
about other aspects of the corneal
surface that can help practitioners
make a decision. This includes:
• Elevation Map. This indicates
the most elevated area of the
cornea, which is crucial to know
when selecting a lens to fit. If the
elevation is decentered, a reverse
geometry scleral lens allows for
vault in the midperiphery without
too much central clearance.
• HVID. Horizontal visible iris
diameter is an important measurement because it is necessary for the
scleral lens to clear the limbus and
land outside the corneal/scleral
junction. Knowing the HVID measurement of the patient’s eye will
help you select the right diameter
for your patient.14
• Sagittal Height. The most
accurate method of selecting an
initial scleral lens, sagittal height is
the measurement from the center
of the cornea to the intersection
of a specific chord length. Most
topographers give the sagittal
depth of the patient’s cornea to a
chord length of 10mm. If fitting a
15mm lens, 2,000µm—the average
sagittal height for most eye types
from a chord length of 10mm to
15mm—will need to be added.12
Another 350µm should also be
included to account for necessary
corneal clearance. Sagittal height
will also need to increase when increasing the lens diameter; roughly
300µm per millimeter of lens diameter change is considered ideal.14
• Fitting the Periphery. New
technology from a few different
companies has given us the ability
to map the scleral contour, making it easier to fit patients with
toric scleras. Visionary Optics has
a unique design that maps scleral curvature to better align the
peripheral fit of its Europa lenses.
The sMap3D system (Precision
Ocular Metrology) incorporates
raster photogrammetry, which
takes multiple, triangulated
measurements using a projector
and two cameras to determine
corneal and scleral measurements.
Fluorescence is used to image the
bulbar conjunctiva. Images are
taken while the patient is looking straight ahead, up and down;
these three images are then pieced
together to create a three-dimensional model of the eye, sent to the
laboratory and used to assist in the
manufacturing of the lens.14
I
n conclusion, a proper assessment and comparison of the
various topographical maps will
enable practitioners to streamline contact lens fitting. Some say
contact lens fitting is more of an
art form than a science. With that
said, I don’t believe technology
will ever fully replace the judgment
of a skilled practitioner; however,
if used properly, topographers
can assist in reducing chair time,
increasing patient success and
keeping costs down.
RCCL
1. Gas Permeable Lens Institute. GP Lecture
Series. Available at: www.gpli.info/gp-lecture-series/. Accessed November 10, 2015.
2. Szczotka-Flynn L, Jani BR. Comparison of
axial and tangential topographic algorithms for
contact lens fitting after LASIK. Eye Contact
Lens. 2005 Nov;31(6):257-62.
3. Sutphin J, Dana R, Florakis G, et al. Basic and
Clinical Science Course, Section 08: External
Disease and Cornea. San Francisco: American
Academy of Ophthalmology. 2006-2007:39-48.
4. Barbara A. Textbook on Keratoconus: New
Insights. New Delhi: Jaypee Highlights Medical
Publishers. 2012:50-51.
5. Hansen D. Evaluating the eye with corneal
topography. Contact Lens Spectrum. August
2003.
6. Indovina K, Potter R. Eccentricity changes in
GP lens design. Contact Lens Spectrum. April
2008.
7. Brujic M, Miller J. Repurposing the office topographer. Review of Cornea and Contact Lens.
June 2012.
8. Eiden B, DeNayer G, Brafman S, et al. Using
advanced technologies for contact lens fitting.
Contact Lens Spectrum. August 2012.
9. Sindt C. Evaluating virtual fitting for keratoconus. Contact Lens Spectrum. May 2011.
10. Kaufman H, Barron B, McDonald M. The Cornea, 2nd Ed. Butterworth-Heinemann 1998.
11. Geerards AJ, Vreugdenhil W. Khazen A. Incidence of rigid gas-permeable contact lens wear
after keratoplasty for keratoconus. Eye Contact
Lens. 2006 Jul;32(4):207-10.
12.Hom M, Bruce A. Contact Lens Prescribing
and Fitting. 3rd ed. Philadelphia: Butterworth,
Heinemann, Elsevier. 2006.
13. Phan VA, Kim YH, Yang C, Weissman BA.
Bitoric rigid gas permeable contact lenses in the
optical management of penetrating keratoplasty.
Contact Lens Anterior Eye. 2014 Feb;37(1):16-9.
14. Jedlicka J, Denaeyer G. Critical measurements
to improve scleral lens fitting. Review of Cornea
and Contact Lenses. September 2015.
17
1/27/16 12:16 PM
Forward
By Jane Cole,
Contributing Editor
T
alk to any contact lens
practitioner about the
patient habits that
bother them most and
“failure to replace lenses on time” will always be near
the top of the list. Patients have
been known to come in wearing
lenses that are months or even
years past their expected replacement date. Despite all the education about health benefits and
greater comfort from frequent or
daily replacement, a fair amount
of patients just don’t feel compelled to change something they
perceive to be working just fine.
Are practitioners sometimes
guilty of the same inertia? Many
rely on a few go-to modalities—
tried and true lenses they have
turned to for years because they
believe in the idea, “If it’s not
broke, don’t fix it?” If patients
wearing older lenses remain truly
happy and healthy, odds are they
can continue without incident. But
if such habits keep practitioners
from exploring newer designs
that might lead to more success
with existing or new lens wearers,
experts say it’s time to break from
this routine; it could be holding
the practice back.
“We often don’t even realize
the habits we develop in clinical
practice,” says Mile Brujic, OD,
of Premier Vision Group in Ohio.
“Certain procedures and protocols
THINKING:
become so routine that we don’t
even think about them. This is
most often true in our contact lens
practices.”
Many of today’s new lens designs provide patients with more
comfort and clarity, and fewer
limitations, than ever before. But
doctors who feel their current
product mix is good enough will
miss out.
Practice management consultant Gary Gerber, OD, of New
Jersey adds that incorporating
new lens options demonstrates
a message of progress. “Just
like many patients are wired
and plugged in [with the latest
technology] to some extent, they
also expect their consumer and
health care experiences to be as
up to date,” he says. “If you do
not offer new products, or at
least mention or broadcast that
you do—even if they may not be
clinically appropriate for every
patient—you’re sending a message
that not only are you out of date,
but out of touch.”
LENSES AS
PRACTICE BUILDERS
“Recent advancements make it
possible to fit almost anyone in
contact lenses, if they so choose,”
says optometrist Gina Wesley of
Complete Eye Care Medina in
Minnesota. “Between the expansion of the daily disposable
parameters in torics and multifocals, colored lenses, new monthly
options and the wide range of
prescriptive sclerals, advancements
in this arena have never looked
better.”
These options offer practitioners
the ability to fit a patient quicker and more effectively, which
increases the value of the service
offered, she adds. “Your patient
appreciates the advancements and
less chair time is necessary, which
is better for the practice. New
designs open the door to multiple
contact lens prescriptions, just like
we prescribe multiple spectacle
prescriptions.”
Newer lens designs also offer
distinct financial benefits to the
practice, in addition to their major
health benefits to patients, says
David Kading, OD, of Specialty
Eyecare Group in Seattle. Though
some of the newer options have
higher price tags, Dr. Kading
believes optometrists should still
market these lenses to patients
because of their positive effect on
patient well-being.
“As optometrists, we often
don’t think our patients are
willing to update beyond the old
technology because it’s going to
cost more money or because the
patient may think that what they
have is fine or good enough,” he
says. “Our job is not to save our
patients money or keep them in
p18_RCCL0216_F2 FowardThinking.indd 18
1/27/16 12:24 PM
Where Can New Lenses
Lead Your Practice?
From sclerals to daily disposables and tinted lenses, new des
designs can add to your
practice if you’re willing to change your mindset.
‘good enough’ lenses, but to give
them the healthiest and most appropriate option for their unique
needs. With that mindset, we need
to educate patients on the new
designs and technologies that will
ultimately serve their long-term
better health.”
Maintaining the belief in the
individual as one’s best source of
Photo: Stephanie Woo, OD
marketing for contact lens fittings
pays off, Dr. Wesley points out.
“You know exactly what this
patient would benefit from, or is
eligible to wear, and you can tailor
your message to give that patient
options. This, in turn, leads to
word-of-mouth and referrals.”
Initially, she discloses, in 2012
only 8% of her contact lens patient base wore a
daily disposable
lens; that number is up to 75%
today.
For Justin
Bazan, OD, of
Park Slope Eye in
New York, more
contact lens design
options mean an
achievement of
better performance
in both the industry and private
practice. “We have
seen advances
in contact lens
materials develop to the point
where end-of-day
comfort issues are
minimal—if not
non-existent—for
many patients,” he
says. And newer
designs benefit
wearers “because
Dr. Woo prepares to take a mold of a patient’s sclera
with the EyePrintPro scleral lens design system.
they provide the
patient with the performance
they demand and need,” he says.
“They help benefit the practice by
generating strong word of mouth
and help build the practice’s positive reputation in the community.”
SPECIAL DELIVERY
When Stephanie Woo, OD, joined
her practice in Arizona, this
board member of the Scleral Lens
Education Society knew she faced
a major challenge. The 25-yearold practice focused on primary
care and ocular disease management, not on specialty lenses as
she had hoped. However, Dr. Woo
wasn’t deterred.
“I knew there had to be plenty
of potential specialty contact lens
patients out there that just didn’t
know what options they had,” she
says. “I was committed to recommending specialty contact lenses
to any patient who was a good
candidate.” Most of her current
specialty lens wearers began as
‘regular’ patients sitting in her
chair for their annual eye or contact lens exam. Today, Dr. Woo
estimates she sees three to four
returning specialty lens patients on
a daily basis and performs three
to five new fits per week. These
include gas permeable (GP), bitoric, GP multifocals, scleral lenses
for regular and irregular corneas,
scleral multifocals, soft custom
lenses, prosthetic soft lenses,
19
1/27/16 12:24 PM
FORWARD THINKING: WHERE CAN NEW LENSES LEAD YOUR PRACTICE?
for the practice, he says, “more
importantly, the patients who
need them are often on disability,
unable to work, can’t see well
or comfortably go about their
day. And, we’re able to quickly
improve their life. What could be
better than that?”
DAY-TO-DAY BENEFITS
Daily disposable contact lens options are another distinct piece of
the market, one that has benefited
from materials advances in recent
years that improve comfort without compromising quality. One
of the best ways to introduce the
possibility of daily disposable contact lenses to patients is to simply
ask how comfortable they are in
their current lenses. When doing
so, avoid simple yes/no questions.
You want to engage the patient in
conversation.
“A number of patients who
come into our contact lens practices are less comfortable in their
lenses than we think they are,”
explains Dr. Brujic. He adds that
while a patient may say they are
happy and comfortable in their
current lens, they may actually
be very close to petering out of
contact lens wear. As a method
of dropout detection, Dr. Brujic
routinely asks his patients to rate
their comfort level 10 minutes after they place lenses on their eyes
in the morning on a scale of one
to 10. Then, he asks his patients
to grade their comfort five to 10
minutes prior to removing the
lenses in the evening.
“We have found, in these seemingly happy contact lens wearers,
that there is a precipitous drop.”
He’ll then investigate closely at
the slit lamp for clinical factors affecting the ocular surface. “But, it
also gives me a great opportunity
to talk about new technologies,”
he says.
Photo: Jason Miller, OD
orthokeratology, myopia control,
hybrid lenses, hybrid multifocals
and EyePrint ocular prosthetic
lenses.
By offering specialty lenses, Dr.
Woo gives options to patients who
thought they would never see that
clearly again. This is both truly
rewarding in the personal sense
and also a benefit to her practice,
she says.
“Specialty contact lens patients
are extremely loyal to the practice,
and offering this unique service
helps our business grow,” Dr. Woo
explains. “Specialty lens patients
are some of the happiest patients,
and they are quick to refer all of
their friends and family to the
clinic. It gives us the opportunity
to help many people.”
For other optometrists looking
to add specialty lenses to their
practices, her marketing advice
is simple: explain to the patient
during the exam why they would
be a good candidate. Dr. Woo
also suggests directing the patient
to try a new contact lens, letting
them know it may improve their
vision and also reassuring them
that if the lens doesn’t improve vision or if the fit is uncomfortable,
they can always return to wearing
their old contacts or glasses.
“This statement puts patients
at ease, knowing they are not
inadvertently committing to these
lenses if things don’t work out.
Most of my patients are willing to
at least try a specialty lens if they
understand why they need it.”
Dr. Kading points out that
sclerals are one of the hottest
areas of growth in the contact lens
industry. “I think custom lenses
are one of the biggest innovations
in the past few years, and they are
also providing a dramatic impact
on patients’ lives,” he explains.
While it’s true that scleral lenses
can generate substantial revenue
Encouraging contact lens patients
to share their experience on social
media is another way to market your
practice. It builds word of mouth
about what makes your care unique.
Dr. Kading estimates the newer
generation of daily disposables
represents 93% of his contact lens
wearer population. In addition to
greater comfort, Dr. Kading believes dailies are the healthiest and
most innovative of the soft lens
options for his patients. Patients
who are recommended dailies tend
to purchase their lenses at regular intervals. “Being compliant is
obviously better for the patient’s
health,” he says. Typically, a sale
of daily disposable lenses pays the
practice double what a monthly
disposable lens would pay. To offset the higher cost of the lenses for
the patient, he typically informs
them they will save between $200
and $400 annually by not having
to purchase contact lens solution.
“That profitability is obviously
much appreciated,” Dr. Kading
acknowledges, “but again, first
and foremost, we want to do
1/27/16 12:24 PM
what is in the best interest of the
patient.”
TARGETING PRESBYOPES
Many of today’s presbyopes want
to lose their glasses—and new
multifocal contact lens designs
provide attractive options for
patients as well as another avenue
to expand a practice. This is an
often-cited area of practice where
old habits and misperceptions do
a disservice to patients and practices alike. Multifocal lenses, while
still requiring patient adaptation
and realistic expectations, have
evolved rapidly in recent years.
Dr. Kading believes that the use
of practice management software
can help identify patients that
are suited for newer presbyopia
lens designs, giving practitioners
the opportunity to target them
through direct mail, social media
and e-mail. He says that from a
marketing standpoint, it’s best to
specifically target the appropriate
patient base for multifocal lenses,
so practitioners can avoid coming
across in an inappropriate manner
to those who are not good candidates. Additionally, it saves time.
“It’s like sending out a Lipitor
commercial to the mass public,”
he explains. “It’s definitely going
to benefit some people, but for
others, it’s going to be a waste
of time and money. We want to
make sure our marketing is very
pointed.”
For those who’ve previously
worn or at least tried multifocals,
eliciting the source of their dissatisfaction can help you tailor the
new message. What one patient
struggled with—e.g., reduced
comfort, poor intermediate vision,
astigmatism—another might not
w Tech
Ne
n
MEETINGS
T
he opportunity to expand
your contact lens practice
and increase your bottom line has
never been greater. For those still
clinging on to their usual contact
lens staples, your colleagues suggest it’s high time for a change.
“My challenge for you is to
think about why you are selecting
the lenses that you are and remember that there is a large armamentarium of lenses to select from that
may better benefit your patient,”
Dr. Brujic says. “Do this and you
will reinvigorate your contact lens
practice, not only in enhancing
your perspective on lens selection
but also by providing your patients the best lens possible.”
N T
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even notice. This is a good opportunity to explain that today’s options are likely better than when
they first tried and failed.
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1/27/16
1/27/16 4:56
4:55 PM
PM
Artificial Tears:
Looking Beneath the Surface
M
anaging patients with
dry eye symptoms
remains a wellknown challenge
despite the wide array
of topical, mechanical and oral
therapies available today. To put
it another way, there would be no
need for palliative artificial tears if
we could truly conquer the under-
Table 1. Approved Active Demulcents
Demulcents
Concentration
Range
Function
• Carboxymethylcellulose
sodium
0.2% to 2.5%
• Increases viscosity (thickener) and
stabilizes emulsions.
• Dextran 70
0.1% (when used
with another
demulcent)
• Increases mechanical strength of
tear film.
• Requires thickener due to low
viscosity of compound.
• Gelatin
0.01%
• Gelling agent that is seldom
included.
• Glycerin
0.2% to 1%
• Lubricant and humectant.
• Blunts the damaging effects of high
osmolarity on the ocular surface.
• Promotes epithelial cell growth.
• Hydroxyethyl cellulose
• Hydroxypropyl-methylcellulose
• Methylcellulose
0.2% to 2.5%
• Crosslinks upon contact with tear
film due to pH difference to increase
viscosity.
• Too viscous to instill easily alone.
• Polyethylene glycol 300
• Polyethylene glycol 400
0.2% to 1%
• Increases viscosity and forms
protective layer over mucous
membrane to relieve irritation.
• Polysorbate 80
0.2% to 1%
• Stabilizes oil emulsions.
• Polyvinyl alcohol
0.1% to 4%
• Lowers tear viscosity.
• Povidone
0.1% to 2%
• Lubricates and soothes.
• Lipid that integrates with existing
oil layer, thickening it and reducing
evaporation.
• Propylene glycol
0.2% to 1%
• Forms a protective layer over
mucous membranes, relieving
inflammation.
• Increases viscosity.
• Holds up to three times its own
weight in water.
lying processes that lead to dry eye
symptoms. Although treatment options abound, they are fraught with
compromises and shortcomings.
Technological advances like
LipiFlow (TearScience), BlephEx
(Scope Ophthalmics) and intense
pulsed light (IPL) devices have been
used to treat meibomian gland
dysfunction (MGD)—the most
common form of dry eye—and
Demodex; however, equipment
costs and space requirements often
limit widespread use in practice.1
Practitioners can also prescribe
less expensive options like hot
compresses and lid soaks to loosen
debris and instigate meibum flow,
but some critics say heat from these
treatments does not penetrate deep
ABOUT
ABOU
AB
OUT
OU
T TH
THE
E AU
AUTH
AUTHORS
THOR
TH
ORS
OR
S
Dr. Christensen is currently
director of clinical research
and an attending doctor
in the cornea and contact
lens and adult primary
care services at Southern
College of Optometry.
Dr. Larson attended and
completed a residency
at Pennsylvania College
of Optometry at Salus
University following work
as high school teacher for
two years. After three years
in private practice in northern
Virginia, she joined the faculty
at the University of Iowa as a contact lens
and dry eye specialist.
p22_RCCL0216_F3 Artificial Tears.indd 22
1/27/16 12:25 PM
These seemingly simple drops are more complex than you think.
Do y
you know what’s in the
them?
em?
By Mike Christensen, OD, PhD,
and Tressa Larson, OD
enough or last long enough to have
a positive effect on MGD.
Other therapies like lid disinfectants (e.g., Cliradex and Avenova)
or lid scrubs (e.g., Ocusoft,
TheraTears and Systane) have also
been used to treat blepharitis; these
have shown a clinical benefit when
used regularly.2 Long-term effects
with respect to more chronic cases
remain unknown, however. Other
research has suggested omega-3 and
omega-6 fatty acids taken orally
may have a positive but limited
effect on meibomian gland inflammation and oil quality. Autologous
serum and amniotic membranes
(e.g., Prokera, AmbioDisc and
BioDOptix) may be used to enhance epithelial repair, but remain
expensive and hard to procure.
In light of these controversial
options, many practitioners would
agree the first-line treatment for
dry eye remains over-the-counter
(OTC) artificial tears. OTC tears
are simple enough to use, with a
variety of well-known indications,
including dryness, irritation and
discomfort relief. However, despite
their simple indications, these drops
are complex formulations with a
host of active and inactive ingredients that can be difficult to evaluate.
Why is this?
Table 2. Approved Active Emollients
Emollients
Concentration
Range
Function
• Anhydrous lanolin
1% to 10% in
combination
with one or more
listed oleaginous
emollient.
• Lubricates and soothes..
Up to 50% in
combination with
one or more listed
emollient.
• Replaces or thickens lipid layer to
increase tear stability and TBUT.
Up to 5% in
combination with
one or more listed
emollient.
• Seals in moisture.
Up to 100%.
• Lubricant that contributes to oil
layer.
Up to 5% in
combination with
one or more listed
emollient.
• Contributes to oil layer.
• Lanolin
• Light mineral oil
• Mineral oil
• Paraffin
• Petrolatum
• White ointment
• Contributes to oil layer.
• Seals in existing moisture, but is
non-moisturizing.
• Waxy consistency.
• White petrolatum
• White wax
• Yellow wax
FDA FOLLIES
Last year, Dr. Christensen received
a call from a friend looking for
information on studies used for approval of OTC tears, as he had been
having difficulty locating any. What
he didn’t realize was that none
currently exist. Though numerous
well-controlled industry-sponsored,
randomized clinical studies that
support product package claims are
available, no FDA trials for drop
efficacy have been instituted.
Why are some ingredients labeled
as active and others inactive, and
why do the companies seemingly
only expound on what is special
about the inactive ingredients?
What differentiates one company’s
product from that of a competitor
with the same active ingredients?
In 1988, the FDA finalized a
monograph to help expedite artificial tears, coded “lubricant eye
drops,” to the market.2 Its primary
purpose was to reduce the costs
and barriers associated with new
product development, thus easing
manufacturing and marketing
efforts. Under the new document,
23
1/27/16 12:25 PM
ARTIFICIAL
AR
A
RTIFICIAL TEA
EARS
E
RS:: LO
RS
LOOKING
LOOK
O IN
NG BENEATH THE SURFACE
the company must notify the FDA
of its intention to release an artificial
tear to the public. To approve the
drop, the agency evaluates its safety
via toxicology testing and checks to
ensure good manufacturing procedures. The monograph contains
specific details on the indications for
use; namely, one of the following:
• Temporary relief of burning and
irritation due to dryness of the eye.
• Temporary relief of discomfort
due to minor irritation of the eye or
to exposure to wind or sun.
• As a protectant against further
irritation or to relieve ocular dryness.
• As a lubricant to prevent further
irritation or to relieve ocular dryness.
Table 3. Approved Inactive Ingredients
Inactive Ingredients
Function
• Sorbitol
• Lowers the viscosity of gelling agents.
• Dissipates quickly, optimizing viscosity.
• Hyaluronic acid
• Binds multiples of its weight in water.
• Lowers tear osmolarity.
• Adheres to ocular surface.
• Stabilizes and evens out the tear film.
• Highly viscous until blinking thins it out.
• Improves cell-cell adhesion.
• Sodium hyaluronate
• Protects and promotes healing of corneal epithelium.
• Changes viscosity upon blinking (i.e., more viscous
while the eye is open).
• Improves tear break-up time and helps spreading.
• Helps control localized inflammation.
• Reduces mucous strands.
• Lowers tear osmolarity.
• Retains water, increasing surface wettability.
• Levocarnitine
• Erythritol
• Blunts the damaging effects of high osmolarity by
preventing stress activation.
• Absorbed by dehydrated cells to promote hydration.
• Prevents cell shrinkage and inflammation.
• Hydroxypropyl guar
• Increases viscosity.
• Mimics the mucin layer of the eye.
• Binds to cornea and aqueous layer.
• Prolongs the efficacy of active ingredients.
• Actively crosslinks/gels at pH above pH 7.
• Polyacrylic acid
• Increases viscosity/retention time of tears.
• Tyloxapol
• Surfactant and mucolytic agent.
• Tromethamine
• Organic amine proton acceptor.
• Emulsifying agent that thins waxy agents.
• Boric acid
• Borate buffer
• Sodium-citrate
• Phosphate
• Phosphate-acetate
• Phosphate-citrate
• Phosphate-citrate-bicarbonate
• Sodium hydroxide
• Buffer systems used to obtain a pH for the artificial
tear that is healthy and comfortable for the eye.
• A pH of 8.5 is most comfortable for dry eye patients
(normal tear pH is about 7.5).
• Calcium chloride
• Magnesium chloride
• Potassium chloride
• Zinc chloride
• Sodium chloride
• Sodium citrate
• Sodium lactate
• Sodium bicarbonate
• Electrolytes are added to maintain or lower tear
osmolarity, as high osmolarity products pull water
from epithelial cells, interfering with metabolism.
• Some of the added electrolytes are also important
for corneal epithelial metabolism.
• Some electrolytes are part of buffer systems.
The FDA also requires manufactures to include the following box
statement on the box: “Stop use and
ask your doctor if you experience
eye pain, changes in vision, continued redness or irritation of the eye,
or if the aforementioned condition
worsens or persists for more than
72 hours.”
The active ingredients in the
monograph comprise a list of
demulcents or emollients (Tables
1 and 2).3-7 A demulcent is a high
molecular weight polymer substance
that relieves irritation of the mucous
membranes by forming a protective
mucous-mimicking film that acts to
lubricate, protect and increase the
viscosity of the eye drop. Emollients,
in contrast, are oleaginous substances that include fats and oils, which
work to reduce evaporation. As part
of the monograph’s development,
the FDA deemed a specific range of
concentrations as safe and effective
for these drugs; it was also decided
that extra or repetitive testing was
unnecessary for future products.
In this sense, the ingredients listed
in the monograph are “safe,” and
overuse constitutes minimal risk to
the patient. Only these ingredients
can be considered for the fast track
of FDA approval. Therefore, the
result of the simplified monograph
ruling had an unforeseen consequence: it has resulted in a plethora
of products on the shelf but no new
active ingredients in nearly 30 years.
A new polymer requires a new
drug application process to show
that it is a pharmacologically active
drug. Significant improvement in a
sign and symptom must be shown;
additionally, results using the new
formula must be demonstrated. This
is an exceedingly difficult task and
sometimes not worth the investment
of time and funding, since it can be
added as a non-pharmacologically
active polymer under the non-active
ingredients.
1/27/16 12:25 PM
San Diego
Up to
25 CE
Credits
(COPE approval pending)
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Joint Meeting
April 7 - 10, 2016
OPTOMETRIC CORNEA, CATARACT
AND REFRACTIVE SOCIETY
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2016
(Formerly OCRT)
New in 2016 Unique Joint Meeting of Review of Optometry NT&T
and OCCRS offers combined 25 CE credits.
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ARTIFICIAL TEA
AR
EARS
RS:: LO
LOOK
O IN
NG BENEATH THE SURFACE
DIFFERENCE MAKERS
Other than the typical ingredients in
artificial tears like boric acid, calcium chloride, magnesium chloride,
potassium chloride, purified water
and preservatives, inactives like
hyaluronic acid along with hydroxypropyl guar, erythritol/levocarnitine
and sodium provide the distinguishing factors that give each artificial
tear its unique characteristics,
improving their efficacy (Tables 3
and 4). 3-7 For example, BlinkTears
(AMO) contains polyethylene glycol
400 0.25% as an active ingredient
and sodium hyaluronate as an inactive ingredient. Sodium hyaluronate
is a humectant that binds many
times its weight in water, reduces
mucous strands and is better at lowering tear osmolarity than glycerin.9
Refresh Optive Advanced (Allergan)
incorporates carboxymethylcellu-
lose sodium 0.5%, glycerin 1% and
polysorbate 80 0.5% as actives with
castor oil, erythritol, levocarntine
and carbomer copolymer type A as
inactives. Systane Ultra (Alcon) uses
polyethylene glycol 400 0.4% and
propylene glycol 0.3% in conjunction with HP-guar as an inactive.
Retaine MGD (Ocusoft) contains
light mineral oil 0.5% and mineral
oil 0.5% as actives and a number of
inactives (e.g., cetalkonium chloride,
glycerol, poloxamer 188).
There can also be differences in
pH and osmolarity, depending on
the characteristics the company
wants to exhibit. Systane Gel Drops
(Alcon) fall at pH 7.0, while Systane
Ultra (Alcon) falls at 7.8. A pH that
more closely matches that of the patient’s tears will result in less stinging on instillation and better overall
comfort. Some tears are significantly
hypoosmotic to the tear film, which
is around 305 mOsmols (for example, TheraTears is at 181 mOsmols),
while others are isosmotic or just
slightly hypoosmotic. In general, a
tear that is relatively hypoosmotic to
the tears of the patient will blunt the
damaging effects of high osmolarity.10 Lowering osmolarity generally
improves OSDI scores, with an
increased effect in younger patients
and those with hyperosmotic tears.
I
n addition to OTC eye drops, a
number of companies have been
diligently working on the development of new prescription drugs for
dry eye, but none have thus far met
the criteria for approval. Dry eye
treatment trials include subjective
accounts of patient comfort, and
the FDA is typically wary of using
subjective data as a factor in its ap-
Table 4. Approved Preservatives
Preservative
Concentration
Range
Additional Effects (+/-)
• Benzalkonium chloride (BAK)
0.004% to
0.02%
• Increases drug penetration.
• Extends product shelf life.
• Disrupts tight junctions.
• Accelerates epithelial desquamation.
• Promotes apoptosis at low concentrations and necrosis at high concentrations.
• Stimulates production of inflammatory cytokines.
• Reduces aqueous production.
• Causes reversible and non-reversible neurotoxicity, reducing nerve fiber density.
• Polyquaternium-1
0.001%
• Causes superficial epithelial damage. Reduces the density of conjunctival goblet
cells, which decreases aqueous tear film production.
• Bacterial cells attract it, but human corneal epithelial cells tend to repel it.
• Sodium perborate
• Vanishing preservative: Upon exposure to an aqueous environment, it is catalyzed
into hydrogen peroxide, water and oxygen.
• Alters protein synthesis within bacterial cells by oxidizing cell membranes and
altering membrane-bound enzymes, causing enzymatic inhibition.
• Stabilized oxychloro complex
0.005%
• Degrades to water, oxygen, sodium and chlorine free radicals when exposed to light.
• Chlorine free radicals are thought to inhibit microorganism protein synthesis within
cells by way of glutathione oxidation, which causes microbe cell death.
• Broad antimicrobial activity—includes antibacterial, antifungal and antiviral effects.
• Sodium chlorite
0.005%
• Mixture of 80% chlorite, 11% sodium chloride, water and trace electrolytes that breaks
down into sodium and chloride ions, oxygen and water when exposed to light.
• Polyhexamethylene biguanide
(PHMB)
0.02%
• Beneficial against bacteria and Acanthamoeba, however, its antifungal activity is
limited. Lethally alters the transcription of bacterial DNA.
• Nonirritating to human corneal cells.
• Integrates into bacterial cell walls, disrupting the membrane.
• Chlorobutanol
• EDTA (edetate disodium or
ethylene diamene tetraacetic acid)
• Alcohol that increases lipid solubility and is able to cross the bacterial lipid layer. Has
extensive anti-bacterial action, causing cell lysis by disruption of microbial cell
membrane lipid configuration.
• Causes significant keratitis and irritation to the ocular surface, but less than BAK.
1%
• Chelating agent that binds metals, which inactivates them.
• Enhances the activity of quaternary ammonium bases and sorbate.
1/27/16 12:26 PM
proval process. For these and other
reasons, Restasis (cyclosporine,
Allergan) has remained the only
prescriptive dry eye drug for over a
decade. While others will eventually
follow, until that time, it is important to understand the difference in
the inactive ingredients contained in
OTC eye drops and make specific
recommendation to your patients.
Even a savvy ingredient-reading
patient may not be able to make
sound choices in eyedrop use simply
by reading the package labeling, so
offer informational packets in-office,
and discuss all potential complications with other medications the
patient may be taking.
RCCL
1. Nichols KK, Foulks GN, Bron AJ, et al. The international workshop on meibomian gland dysfunction: executive summary. Invest Opthalmol Vis Sci,
2011;52:1922-9.
2. Duncan K, Jeng BH. Medical management
of blepharitis. Curr Opin Ophthalmol, 2015
Jul;26(4):289-94.
Is There Science Behind the Slogans?
Ironically, while the FDA does not require studies to demonstrate
efficacy of drops based on its active ingredient list, the agency
does require proof for advertising and marketing claims in the
form of results from clinical studies or market research. Approved
on-the-box statements like the following must have clinical trials
or other data to back up the claim.
•
•
•
•
•
#1 Doctor Recommended Brand. • Clinically shown to improve
Doctor Recommended.
tear film stability.
Extended Protection.
• Long-lasting relief.
High Performance.
• Relief that lasts up to 8 hours.
Advanced Dual Action Formula.
3. Rules and Regulations. Food and Drug Administration 21 CRF Parts 349 and 369. Federal Register
53(43)March 1988:7076-83.
4. Brafman S, Eiden BS. Finding the balance for
contact lens-associated dry eye. Review of Cornea
and Contact Lenses. Jan 2012.
5. Elder DP, Crowley PJ. Antimicrobial preservatives part one: choosing a preservative system.
American Pharmaceutical Review. Jan. 2012. Available: www.americanpharmaceuticalreview.com/
Featured-Articles/38886-Antimicrobial-Preservatives-Part-One-Choosing-a-Preservative-System/.
6. Freeman PD, Kahook MY. Preservatives in topical
ophthalmic medications: historical and clinical per-
spectives. Expert Rev Ophthalmol. 2009:4(1):59-64.
7. Bartlet JP, Jaanus SD. Clinical ocular pharmacology. 5th ed. Stoneham: Butterworth-Heinemann;
2007.
8. Zheng LL, Myung D, Yu CQ, Ta CN. Comparative
in-vitro cytotoxicity of artificial tears. JSM Ophthalmology. 2015 Jan;3(1):1026.
9. Montani G. Intrasubject tear osmolarity changes
with two different types of eyedrops. Optom Vis Sci.
2013 Apr:90(4):372-7.
10. Corrales RM, Luo L, Chang EY, Pflugfelder SC.
Effects of osmoprotectants on hyperosmolar stress
in cultured human corneal epithelial cells. Cornea.
2008. Jun;27(5):574-9.
BERMUDA
JUNE 9-12, 2016
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s
ogie and
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& T
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IN VISION CARE
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bermuda_half.indd
p22_RCCL0216_F3 1Artificial Tears.indd 27
*Approval pending
1/28/16 2:04
2:09 PM
2 CE
Credits
(COPE Approval
Pending)
REALITY CHECK:
Outdated FDA protocols don’t account for real-world usage, newer lens
materials and virulent organisms. Proposed updates could bring big changes.
By Yvonne Tzu-Ying Wu, PhD, MPH, An Truong, B.Optom, and Fiona Stapleton, PhD
T
here has been a dramatic shift in contact lens
disinfection solutions
in the last decade, with
multipurpose solutions
(MPS) largely replacing more
traditional multiple-step systems
consisting of separate cleaning and
disinfecting liquids, or unpreserved
saline in conjunction with chlorine-releasing tablets. Currently,
over 90% of patients report use
of an MPS for lens disinfection;
hydrogen peroxide, polyhexamethylene biguanide (PHMB)-based
and polyquaternium-1 (Polyquad)/
myristamidopropyl dimethylamine
(Aldox)-based systems are considered the most commonly used.1,2
While use patterns have evolved,
regulatory policy has lagged behind. Manufacturers must comply
with FDA guidelines to obtain
clearance for the sale of contact
lenses and lens care products in the
United States. The guide documents in question—Premarket
Notification 510(k) Guidance
Document for Daily Wear
Contact Lenses and Guidance for
Industry: Premarket Notification
510(k) Guidance Document for
Contact Lens Care Products—
were published in 1994 and 1997,
respectively. Due to subsequent
updates in contact lens technology and reports of adverse health
incidents, including widespread
Acanthamoeba keratitis, these documents have been deemed by many
to be out of date.3-5
The Division of Ophthalmic
and Ear, Nose and Throat Devices
(DOED) has since suggested a
number of changes to these documents—namely, the addition of
a test protocol to evaluate MPS
efficacy against Acanthamoeba
keratitis. Other suggestions include
the prevention of environmental
contamination, particularly as a
result of water contact, and the
impact of contact composition on
MPS efficacy.2 For example, ionic
charge, lens material porosity and
relative hydrophobicity are markedly altered between traditional
hydrogel lenses and newer silicone
hydrogel lenses; these properties
are known to impact microbial adhesion and the uptake and release
of MPS preservatives, which may
compromise disinfection efficacy.6-9
This article provides an overview of specific issues identified
with current MPS guidelines and
standards applicable to MPS
products sold in the United States.
Proposed modifications raised by
various expert bodies in an attempt
to address these issues will also be
discussed.
CONTACT LENS-RELATED
ACANTHAMOEBA
These microorganisms exist
commonly in freshwater and soil
environments as either an active
trophozoite or dormant cyst form,
the latter of which is encased in
a double-layer cellulose wall that
enables it to withstand harsh en-
vironmental conditions, including
exposure to extreme temperature,
pH and dryness.3,4 As a result, they
exhibit resilience to many forms of
disinfection.3-5 Pathogenic organisms known as endosymbionts,
which include Pseudomonas and
mycobacterium, may also grow
and replicate within the cytoplasm
of Acanthamoeba, further enhancing its virulence.6,12
Acanthamoeba keratitis (AK) is
a rare but serious corneal infection that is often sight-threatening
despite medical interventions.
Beginning in June 2003, investigators identified increased
outbreaks of the disease in the
Chicago-Gary-Kenosha metropolitan area; consequentially, Complete
Moisture Plus (AMO) was recalled
in 2007 after a national inquiry
found it resulted in an increased
ABOUT THE AUTHORS
Dr. Wu is a postdoctoral
research fellow at the
School of Optometry
and Vision Science at the
University of New South
Wales, Sydney, Australia.
Dr. Truong has been working
in clinical practice for a
decade. During this time
she also gained a BSci and
continued on to submit
a PhD at the school of
Medicine at the University of
New South Wales, Sydney, Australia.
Dr. Stapleton is the head of
the School of Optometry
and Vision Science at the
University of New South
Wales, Sydney, Australia.
p28_RCCL0216_F4 FDA Testing.indd 28
1/27/16 4:18 PM
HOW FDA TESTING
FALLS SHORT
risk of Acanthamoeba keratitis.13,14
An elevated level of the disease
continued to persist following the
recall, however, suggesting the
recalled MPS may not have been
the sole culprit.7
Several subsequent studies
have endeavored to elucidate the
persistence of the Acanthamoeba
infections post-recall.5,7-9,11,15
Additionally, a microbiology
workshop involving the FDA, eye
care professionals, microbiologists
and members of industry convened
in 2009 to discuss testing protocols for Acanthoamoeba disinfection efficacy.16 Below is a general
overview of the testing parameters
proposed at this meeting:
• What should be the challenge
size for testing MPS in the absence
of a contact lens?
• Which Acanthamoeba strains
should be tested?
• How should the cells be grown
in order to obtain cells in the trophozoite stage of growth?
• How should cells in the cyst
stage be produced?
• How should the number of
survivors of trophozoites or cysts
be measured?
• What should be the protocol to
use when testing for MPS efficacy
in the presence of a contact lens?
• What should the overall performance criteria be for the different
possible test scenarios?
• Should the MPS’s ability to
cause the Acanthamoeba cells to
encyst be measured?
The increase in Acanthamoeba infection risk among contact lens wearers
suggests a need for better FDA testing methods.
Other microbiological test method workshops (one in May 2014;
the latest in November 2014) have
been held by the FDA following the
2009 meeting to accommodate further discussion of test parameters—
namely, what strain of organism to
cover, life cycle (both trophozoite
and cyst stage), growth method and
how to encyst Acanthamoeba?18-20,37
Release Date: February 2016
Expiration Date: February 1, 2019
Goal Statement: This course covers current FDA testing reguations and proposed
changes.
Faculty/Editorial Board:
Yvonne Tzu-Ying Wu, PhD, MPH, An Truong,
B. Optom, and Fiona Stapleton, PhD
Credit Statement: COPE approval for 2
hours of continuing education credit is
No consensus has been reached
thus far regarding an appropriate
microbiological test method for
Acanthamoeba; however, suggestions of critical test parameters include the use of least two different
Acanthamoeba strains in cyst form
and use of an inoculum size no
greater than 1,000 to 10,000 cysts
or trophozoites.
pending for this course. Check with your
state licensing board to see if this counts
toward your CE requirements for relicensure.
Joint-Sponsorship Statement: This
continuing education course is joint-sponsored by the Pennsylvania College of
Optometry.
Disclosure Statement: Drs. Wu, Truong
and Stapleton have no financial interest in
any products mentioned in this article.
REVIEW OF CORNEA & CONTACT LENSES | FEBRUARY 2016 29
1/27/16 4:18 PM
(COPE Approval
Pending)
REALITY CHECK: HOW FDA TESTING FALLS SHORT
Research also indicated
Acanthamoeba grown in the presence of bacteria demonstrate less
variability in their susceptibility
to the MPS tested, as opposed to
when grown axenically (i.e., in the
absence of other microorganisms).21
Acanthamoeba cysts produced
from growth on non-nutrient agar
(known as the starvation method)
are significantly more resistant to
disinfection by PHMB-based MPS
compared with cysts induced by
Neff’s encystment medium.21,22
Therefore, the microbiological and
nutritional environment are both
significant factors in modifying cyst
resistance, and the susceptibility
of Acanthamoeba to biocides may
vary depending on the experimental conditions.
As manufacturers continue to
evaluate MPS efficacy against
the test organisms, precise standardized experimental protocols
and conditions still need to be
defined in order to obtain valid
results from multiple sites. Further
research is also still warranted to
finalize a testing guideline for solution efficacy against the forms of
Acanthamoeba likely to be encountered in real world conditions.
LENS/SOLUTION
INCOMPATIBILITY
Preservative uptake—the absorption of preservative from the
solution within the lens case into
the lens matrix—is evaluated based
on the amount of preservative absorbed from the solution in question at different points in time until
a concentration plateau is obtained.
Release describes the sequestration
of preservative from the lens into
an aqueous solution, such as the
tear film. Distinct factors that affect
uptake and release include water
content, charge, relative hydrophobicity, surface treatment and poros-
ity of lens material, in conjunction
with the concentration, charge,
iconicity in the product matrix, molecular weight and hydrophobicity
of the care component.22 Variations
in the adsorption of the solution
components by lenses can lead to
differences in the amount and rate
of release onto the ocular surface;
both can compromise disinfection efficacy of the solution (see,
“Silicone Takes Over,” page 33).8,9
Preservative uptake and release
are assessed for new solutions according to ISO11986, “Ophthalmic
Optics—Contact Lenses and
Contact Care Products—
Determination of Preservative
Uptake and Release,” which guides
testing to determine if ocular
irritation is likely to occur from
preservative uptake and subsequent
release.
At this time, preservative uptake
is assessed by the International
Standards Organization and is
not currently required for FDA
premarket testing of contact lenses
and lens care products (see, “Going
Global,” page 34). However, the
FDA has proposed updates to its
guidelines advising that manufacturers demonstrate that representative lenses do not decrease the
concentration of preservative below
the specified concentration range
when incubated in a care product
solution. The proposed acceptance
criterion is that preservative concentration in the lens case should
remain within the manufacturer
specifications after the recommended soak time. Lenses that do
not pass should be labeled as such
on the product and packaging or
subjected to additional disinfection
efficacy testing prior to approval
for the US market. This is the first
time an acceptance criterion for
preservative uptake will be introduced into the guidance.
In addition to concerns regarding compromised disinfection
efficacy, preservative uptake and
release are critical determinants for
solution-induced corneal toxicity.
Despite being asymptomatic, a
significant proportion of contact
lens wearers (i.e., 37% of subjects)
that used a PHMB-based system
displayed a level of staining consistent with the classic solution-based
toxicity reaction.24 Studies have
also reported an increased rate of
corneal staining associated with
several care systems in combination
with silicone hydrogel materials.25,26
Several MPS systems were reformulated in an attempt to improve
their compatibility with the newest
lens materials in order to minimize
staining potential. A clinical test
matrix for silicone hydrogel lenses
was also proposed by the FDA to
address clinical performance.
However, some researchers have
questioned whether staining has
significant clinical relevance, casting
doubt on whether the FDA’s clinical
test matrix is appropriately set up
with adequate consideration of
these clinical parameters.
LENS WEAR PATTERNS
Research groups continue to
investigate if lens wear noncompliance may have contributed to a
Fusarium outbreak in the United
States and Singapore.27,28 The major
noncompliant behaviors identified
thus far are: reuse of solutions,
especially after lens storage; lack
of a manual-rub cleaning step;
overnight use of daily wear contact
lenses; and the use of lenses past
their recommended replacement
date.28-30 Other research indicates
poor hand washing and lack of
understanding regarding proper use
of lens care products are other significant noncompliance behaviors,
among others.31-39
1/27/16 4:18 PM
It has been suggested that solution
testing should take into account
such behaviors; however, many
researchers agree testing for such
an array of noncompliant behaviors
and situations is nearly-impossible.
Artificial tear use may also have
an impact on disinfection efficacy.40
Certain artificial tear components
may be used by infective microbes
as a source of energy or to enhance the growth of biofilm on the
contact lens surface.41-43 Handling a
contact lens may also contaminate
its surface with organic material, which can neutralize certain
disinfectants.44 ISO14729 does
not require organic soil to be used
when evaluating MPS disinfection;
however, the September 2014
microbiology workshop yielded the
Inside the Bottle
suggestions of adding an organic
soil test (i.e., 1x107 to 1x108 CFU/
mL heat-killed Saccharomyces cerevisiae yeast cells in heat-inactivated
bovine serum) and an artificial tear
component test (0.5% hen egg
lysozyme, 0.1% porcine stomach
mucin, human serum, 0.2% bovine
serum albumin, 1% albumin,
0.1% mucin and 0.2% mucin)
to the standard testing protocol.
Additionally, recent research has
found that conditioning bacteria
to human tear fluid or corneal
epithelial cells may upregulate virulence gene expression in bacteria,
including those genes resistant to
killing.45,46 Therefore, the antimicrobial efficacy of MPS against
host-conditioned microbes may
be reduced when compared with
Traditional multipurpose disinfection solutions
consist of different components that combine
to achieve various tasks required for contact
lens care. Most MPS products are marketed
as single solutions for cleaning, disinfection
and storage purposes; each has a specific
formulation, though the primary components
typically remain the same. These include:
• Preservatives. These substances are
responsible for killing microbes residing in
and on the contact lenses and also inhibiting
contamination of the MPS solution itself for
prolonged use after opening.21 Preservative
uptake and release profiles vary depending
on the kind used in the MPS formulation,
which can lead to differing disinfection efficacies.15 Too much of a preservative released
from the lens into the tear film can also result
in corneal toxicity.22 Common preservatives
include polyhexamethylene biguanide hydrochloride (PHMB), polyquaternium-1 (PQ-1),
myristamidopropyl dimethylamine, hydrogen
peroxide and polyaminopropyl biguanide.
• Surfactants. These are amphiphilic chemicals similar in nature to a detergent that aid in
removal of loosely bound protein deposits of
an inorganic or lipid nature.41 Due to the amphiphilic nature of surfactants, they may potentially act as lubricants by reducing surface
non-conditioned laboratory standard strains. Use of conditioned
bacteria for ISO testing may better
reflect the actual MPS biocidal
activity against bacteria likely to be
encountered in situ.
While the inclusion of these
parameters is expected to simulate
a more realistic portrayal of daily
lens wear and the factors that might
complicate it, the obstacle once
again becomes how to standardize
such parameters, including how to
ensure uniformity of human tear
conditioning fluid or appropriate
incubation times for artificial tear
interference testing. Thus, establishing standard testing parameters
and setting passing criteria requires
further evaluation to adequately
replicate real life conditions.
tension.23 This increased wettability buffers
interacting ocular tissues from hydrophobic
areas on the surface of the contact lens.42
Typical MPS surfactants include isopropyl
alcohol, sodium citrate, sodium phosphate,
polyvinyl alcohol and sodium borate.
• Chelating Agents. These substances bind
proteins and metals like calcium to prevent
deposition on the contact lens surface.25
Ethylenediaminetetraacetic acid (EDTA) is the
most common MPS chelating agent. EDTA
has been shown to be an adjuvant that can
enhance biocidal activity.69
• Buffers. Buffers help maintain the pH of
the MPS to ensure biocompatibility a enhance
comfort and reliability of the component
agents. Common MPS buffers include borate,
phosphate, bicarbonate, citrate and nitrate.21
• Wetting Agents and Lubricants. These
decrease surface tension to increase the wetting angle of the contact lens surface, which
leads to improved comfort of the contact lens
via reduced friction between the contact lens
and ocular surface and eyelids.21 Common
wetting agents and lubricants include Tetronic 304, poly(oxyethylene)-poly(oxybutylene),
hydroxypropyl methylcellulose, hyaluronic
acid, carboxymethylcellulose and propylene
glycol.
1/27/16 4:18 PM
(COPE Approval
Pending)
Given the controversies, recommendations encourage manufacturers to make evaluating MPS in
the presence of contact lenses a
standard, at least with respect to
biocompatibility. Additionally, lens/
solution incompatibilities should be
labeled on the product and packaging to help contact lens wearers
make an informed decision about
their choice of lens care product.
The FDA has also proposed incorporating other specific parameters,
including the addition of two new
strains of Pseudomonas to the test
panel and use of organic soil to
reflect real-life scenarios.
GP LENS CLEANING
In some cases, contact lenses
and lens cases act as vectors for
microbes derived from the environment, delivering these microorganisms to the ocular surface
where complications may arise.
Studies have identified exposure of
contact lenses to sources of water,
including tap water, as risk factors
for Acanthamoeba keratitis.47-53
However, while rinsing with tap
water has long been advised against
as part of the soft lens care regimen, many GP lens care regimens
continue to include use tap water
for rinsing as part of their care
process.15
The Centers for Disease Control
(CDC) revised its Consumer
Updates website in 2010 to convey
the elimination of water for GP
lens care, and the FDA published
an addendum to the 510(K) contact lens care labeling guidance;
However, some GP lens solutions
continue to recommend its use, and
many consumers remain unaware
of the change.54,55 Potential alternatives to tap water with GP lenses
do exist—for example, sterile saline
rinses—but the uptake of such
options seems to be low.
The group also discussed a related issue regarding scleral contact
lenses, which are typically inserted with a fluid reservoir. Often,
unpreserved saline is used, but tap
water may also be used in some
cases. While this may present several problems, it is not clear how
common this practice is.
BIOFILM FORMATION
Microbial phenotype and gene expression can also affect a microbe’s
susceptibility to disinfectants and
thus the efficacy of a solution. As
mentioned previously, the physical
form(s) of the organism have differing biocide resistances. Bacteria
conditioned with human tear fluid
or with epithelial cells may secrete
factors that hinder biocidal activity.
The low metabolism of bacteria residing in biofilms may also increase
their resistance to antibiotics and
disinfectants.13,56,57
Many studies have reported that
while some disinfecting solutions
perform better than others in
reducing planktonic bioburden,
most were not effective in reducing
biofilm.17,58-61 One study shows
that while planktonic organisms
may be susceptible to PHMBand Polyquad-based disinfecting
solutions, the susceptibility of these
same strains of bacteria contained in a biofilm is considerably
reduced.62
Additionally, microbial adhesion
and biofilm formation is enhanced
in silicone hydrogel lenses compared with conventional hydrogel
lenses.14 Researchers hypothesize
this observation is due to the
increased hydrophobic phases,
increased protein/lipid deposits on
silicone hydrogel lens and higher
oxygen transmissibility/availability.63-66 Even though these observations are mostly in vitro, further
study regarding MPS efficacy
against biofilm should be considered to warrant safe lens wear.
COMFORT AND
CONVENIENCE
Several MPS systems have been
reformulated to improve their
compatibility with silicone hydrogel lens materials in an attempt to
decrease corneal staining potential.
In addition, manufacturers have
tried to improve comfort for lens
wearers by adding wetting agents.
However, while wettability is related to improved lens wear comfort,
the recalls of two MPS systems
(Complete Moisture Plus and
Renu with MoistureLoc) has been
hypothesized to be the result of a
combination of effects, including
the addition of moisturizing agents
for comfort.19,20 No isolated MPS
component appears to be singularly
responsible for enhanced rates of
Acanthamoeba encystment and
thus increased resistance to biocidal
activity.67,68 The interaction of components within a formulation—
biocide, buffer and moisturizing
agent—appear to interplay, in a sofar unpredictable manner, to affect
the eventual biocidal activity.67,68
It is difficult to find the critical
balance between improved wettability and solution disinfection
efficacy without compromising
either. Further research is needed
to carefully evaluate the balance
between these factors for successful
lens wear.
M
embers of the DOED plan
to revise the 1994 guidance
document for daily wear contact
lenses and the 1997 guidance
document for lens care products
to reflect advancements in contact
lens materials, microbial outbreak
incidents and increased understanding of the pathogenesis of certain
microbes such as Acanthamoeba.
1/27/16 4:18 PM
Key issues include consideration of
new organisms and lens materials
in the test panel, lens/solution incompatibility concerns, real-world
factors and clearer labeling for GP
lens products.
Additionally, future emphasis is
expected to be placed on whether
MPS manufacturers should account
for noncompliance in their premarket testing. Clear and consistent instructions for contact lens and lens
case hygiene also remain a critical
measure that should be considered.
Overall, it is anticipated that revision of the ISO18259 standard will
have a significant impact on MPS
safety and the contact lens market;
the specific repercussions remain to
be seen.
Editor’s note: Thank you to Dr.
Nicole Carnt of the Save Sight
Institute, University of Sydney, for
peer reviewing this article.
RCCL
Silicone Takes Over
Silicone hydrogel lenses (the first generation: balafilcon A and lotrafilcon A) were
first introduced to the market in the late
1990s, when manufacturers began to inject
silicone polymers into the original hydrogel
monomers to improve material performance
(i.e., oxygen permeability, ion transport,
deposit resistance and mechanical properties).70 However, while silicone polymers
allow high oxygen transmission, they are
hydrophobic and thus require the hydrogel
polymer water phase to allow transport of
gases like oxygen and carbon dioxide, ions
and tear film components across the lens.
Additionally, the contrasting properties
of the constituent materials of a silicone
hydrogel lens result in significantly different
lens surface characteristics compared to
conventional hydrogel materials, including
wettability, deposition of proteins and lipids
and lens/solution interactions (e.g., uptake
and release of preservative by the lens or
biocide sequestration).71-74
A decades-old grouping system developed over 20 years ago, based on contact
Table 1. Conventional Hydrophilic
Material Groups
Group
Description
I
Low Water Content (<50%), Nonionic*
II
High Water Content (>50%), Nonionic*
III
Low Water Content (<50%), Ionic*
IV
High Water Content (>50%), Ionic*
*Being ionic in pH = 6.0 – 8.0.
lens water content and charge, has proved
effective for predicting potential solution
incompatibilities with the varied range of
poly(HEMA) lenses available on the market;
however, similar incompatibilities could not
be predicted when silicone hydrogel lenses
were added to this conventional grouping
system (Table 1). For example, the multipurpose solution preservative Aldox, which
features a positive charge and hydrophobic tail, demonstrates strong interactions
with silicone hydrogel maTable 2. Silicone Hydrophilic Material Groups
terials—that is, all silicone
hydrogel lenses, regardless
Group
Description
of ionic charge and/or water
content, uptake a greater
V-A
No Water Specification, Ionic*
amount of Aldox compared
V-B
High Water Content (>50%), Nonionic*
to poly(HEMA) contact lenses.15,30,75 A silicone hydrogel
V-C
Low Water Content (<50%), Nonionic*, Hydrophilic-monomer Only
material group was added
to the classification upon
V-Cm
Low Water Content (<50%), Nonionic*, Surface Treated (ST)
identification of this issue
and subdivided into five
Low Water Content (<50%), Nonionic*, Non-ST, Semi-interpenetrating
V-Cr
Network
subgroups to account for
differences in poly(HEMA)
*Being ionic in pH = 6.0 – 8.0.
content (Table 2).
1/27/16 4:18 PM
(COPE Approval
Pending)
Going Global
In most countries, an MPS must meet the International Organization for Standardization (ISO) disinfection criteria before it can
obtain licensing, prior to any specific country requirements. There
are two pathways to obtain ISO
Stand Alone
classification, specified by ISO
Test
18259 (Figure 1).26 The first is for
a solution to satisfy the primary criteria of a stand-alone test;
No
No
Primary
Secondary
Test Failed that is, the solution must have a
Criteria Met
Criteria Met
greater than or equal to 3-log reYes
duction (i.e. 1,000 times smaller
Yes
than the original amount) in each
Regimen
Stand Alone
Test Passed
Test
of the three test bacteria and
a greater than or equal to 1-log
kill (i.e. 10 times smaller than the
No
Regimen
original amount) in each of the
Test Failed
Criteria Met
test fungi. The secondary criteria
for the stand-alone test is that
Yes
the solution must demonstrate
Regimen Test
Passed
the concentration of each of the
three bacterial species is reduced
Fig. 1. Flow chart for Stand-alone
and Regimen Tests specified by ISO by 1 log unit at minimum, and
18259.18
that the sum of the log reductions of the three bacteria exceeds 5 log units.
Supplementing the less stringent secondary criteria of the standalone test is the regimen test, which requires the solution reduce
microbe numbers to a certain level after a lens rubbing and rinsing
process. The specific standards for antimicrobial activity and test
microbes specified by ISO18259 are detailed in Table 3.27
Table 3. Criteria for the Stand-alone and Regimen
Tests for Contact Lens Disinfecting Solutions
Microbe Type
Test
Fusarium
solani
(ATCC
36301)
Candida
albicans
(ATCC
10231)
Pseudomonas
aeruginosa
(ATCC 9027)
Serratia
marcescens
(ATCC
13880)
Staphylococcus
aureus (ATCC
6538)
Stand-alone
Test (Primary
Criteria)
1.0 log
unit
1.0 log
unit
3.0 log unit
3.0 log unit
3.0 log unit
Stand-alone
Test (Secondary
Criteria)
Stasis
at the
soaking
time
Stasis
at the
soaking
time
Minimum 1.0
log unit
Minimum
1.0 log unit
Minimum 1.0 log
unit
Sum of the log reductions of the three
challenge bacteria must exceed 5.0 log units.
Regimen Test
<10CFU
(Includes all mfg. on lens
recommended
procedures,
including rub/
rinse.)
<10CFU
on lens
<10CFU on
lens
<10CFU on
lens
<10CFU on lens
ATCC: American Type Culture Collection; CFU: colony forming units
* Based on average reduction at manufacturer’s recommended disinfection time.
1. Morgan PB, Efron N. A decade of contact
lens prescribing trends in the United Kingdom
(1996-2005). Cont Lens Anterior Eye 2006;
29: 59-68.
2. Woods CA, Morgan PB. Use of silicone
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3. FDA. FDA Executive Summary. Prepared for
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Epidemiol. 2012;19:221-225.
6. Willcox MD. Microbial adhesion to silicone
hydrogel lenses: a review. Eye Contact Lens.
2013;39:61-66.
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8. Rosenthal RA, Dassanayake NL, Schlitzer
RL, et al. Biocide uptake in contact lenses and loss of fungicidal activity during
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9. Rosenthal RA, McDonald MM, Schlitzer RL,
et al. Loss of bactericidal activity from contact
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10. Keay L, Stapleton F, Schein O. Epidemiology of contact lens-related inflammation and
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11. Fiona S, Lisa K, Katie E, et al. The incidence of contact lens-related microbial
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12. Carnt N, Stapletion F. Strategies for the prevention of contact lens-related Acanthamoeba
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association of contact lens solution use and
acanthamoeba keratitis. Am J Ophthalmol
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14. Joslin CE, Tu EY, McMahon TT, et al. Epidemiological Characteristics of a Chicago-area
Acanthamoeba Keratitis Outbreak. Am J
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15. Green AJ, Phillips SAK, Hitchins VM, et al.
Material properties that predict preservative
uptake for silicone hydrogel contact lenses.
Eye & Contact Lens 2012;38:350-357.
16. Willcox M. Acanthamoeba testing for multipurpose disinfecting solutions. Contact Lens
update, 2009.
17. Imayasu M, Tchedre KT, Cavanagh HD. Effects of multipurpose solutions on the viability
and encystment of Acanthamoeba determined by flow cytometry. Eye Contact Lens.
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18. Ahearn DG, Simmons RB, Ward MA, Stulting RD. Potential resistant morphotypes of
Acanthamoeba castellanii expressed in multipurpose contact lens disinfection systems. Eye
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19. Legarreta JE, Nau AC, Dhaliwal DK. Acanthamoeba keratitis associated with tap water
1/27/16 4:18 PM
use during contact lens cleaning: manufacturer guidelines need to change. Eye Contact
Lens 2013;39:158-61.
20. Boost M, Shi GS, Cho P. Adherence of
acanthamoeba to lens cases and effects of
drying on survival. Optom Vis Sci 2011;88:7037.
21. SJ Gromacki, Ward M. Understanding
Contemporary Contact Lens Care Products.
Contact Lens Spectrum 2013;28:20-25.
22. Gorbet M, Postnikoff C. The impact of
silicone hydrogel-solution combinations on
corneal epithelial cells. Eye Contact Lens
2013;39:42-47.
23. Jones L, Powell CH. Uptake and release
phenomena in contact lens care by silicone
hydrogel lenses. Eye Contact Lens 2013;39:2936.
24. Rao SK, Lam PT, Li EY, et al. A case series
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in Hong Kong. Cornea 2007;26:1205-9.
25. Willcox M. Review of recent recalls of contact lens multipurpose disinfecting solutions.
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26. Ahearn DG, Zhang S, Stulting RD, et al.
Fusarium keratitis and contact lens wear: facts
and speculations. Med Mycol. 2008;46:397410.
27. Chang DC, Grant GB, O’Donnell K, et al.
Multistate outbreak of Fusarium keratitis
associated with use of a contact lens solution.
JAMA. 2006;296:953-3.
28. Levy B, Heiler D, Norton S. Report on testing from an investigation of fusarium keratitis
in contact lens wearers. Eye Contact Lens
2006; 32:256-61.
29. Morgan PB, Efron N, Toshida H, Nichols
JJ. An international analysis of contact lens
compliance. Contact Lens and Anterior Eye
2011;34:223-28.
30. Asbell PA, Dunn MJ, Schechter CB, et al.
Compliance in the care of disposable contact
lenses: the effect of patients’ health beliefs.
CLAO J 1993 Jul;19(3):150-2.
31. Claydon BE, Efron N. Non-compliance in
contact lens wear. Ophthalmic Physiol Opt
1994;14:356-364.
32. Collins M, Shuley V, Coulson J, Bruce A.
Initial compliance with lens care instructions. Clinical & Experimental Optometry
1993;76:115-118.
33. Collins MJ, Carney LG. Patient compliance
and its influence on contact lens wearing
problems. American journal of optometry &
physiological optics. 1986;63:952-61.
34. Dumbleton K, Richter D, Woods C, et al.
Compliance with contact lens replacement in
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35. Hay J, Munro F, Seal D. Testing contact
lens wearer hygiene compliance. Optician
1995;209:26-29.
36. Mayers M, Callan B, Borazjani R. Compliance and contamination in contact lens
wear. American Academy of Optometry 2010:
Program Nr:105090.
37. Hildebrandt C, Wagner D, Kohlmann T,
Kramer A. In-vitro analysis of the microbicidal
activity of 6 contact lens care solutions. BMC
Infect Dis 2012;12:241.
38. Pinna A, Usai D, Zanetti S. Pseudomonas
aeruginosa growth in Refresh Plus(R). J Ocul
Pharmacol Ther. 2011;27:561-564.
39. Yadav MK, Chuck RS, Park CY. Composi-
tion of artificial tear solution affects in vitro
Pseudomonas aeruginosa biofilm formation
on silicone hydrogel lens. J Ocul Pharmacol
Ther. 2013;29:591-4.
40. Dutta D, Cole N, Willcox M. Factors influencing bacterial adhesion to contact lenses.
Mol Vis. 2012;18:14-21.
41. Gorscak JJ, Ayres BD, Bhagat N, et al. An
outbreak of Fusarium keratitis associated with
contact lens use in the northeastern United
States. Cornea 2007;26:1187-94.
42. Khor WB, Aung T, Saw SM, et al. An
outbreak of Fusarium keratitis associated
with contact lens wear in Singapore. JAMA
2006;295:2867-73.
43. Rao SK, Lam PT, Li EY, et al. A case series
of contact lens-associated Fusarium keratitis
in Hong Kong. Cornea 2007;26:1205-9.
44. Lindsay RG, Watters G, Johnson R, et al.
Acanthamoeba keratitis and contact lens wear.
Clin Exp Optom. 2007;90:351-60.
45. Radford C, Lehmann O, Dart J. Acanthamoeba keratitis: Multicentre survey in
England 1992-1996. British Journal of Ophthalmology. 1998;82:1387-92.
46. Jeong HJ, Yu HS. The role of domestic
tap water in Acanthamoeba contamination in
contact lens storage cases in Korea. Korean J
Parasitol. 2005;43:47-50.
47. Watt K, Swarbrick HA. Microbial keratitis in
overnight orthokeratology: Review of the first
50 cases. Eye Contact Lens 2005;31:201-8.
48. Visvesvara GS. Epidemiology of infections with free-living amebas and laboratory
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1993;60:283-8.
49. Moore MB, McCulley JP, Newton C, et al.
Acanthamoeba keratitis: A growing problem in
soft and hard contact lens wearers. Ophthalmology 1987;94:1654-1661.
50. Woodruff S, Dart J. Acanthamoeba keratitis occurring with daily disposable contact
lens wear. British Journal of Ophthamology.
1999;83:1088-95.
51. Prevention CfDCa. Parasites - Acanthamoeba - Granulomatous Amebic Encephalitis
(GAE); Keratitis. In, 2010.
52. Prevention CfDCa. Parasites - Acanthamoeba - Granulomatous Amebic Encephalitis (GAE); Keratitis. In, 2012.
53. Saw SM, Ooi PL, Tan DTH, et al. Risk factors for contact lens-related Fusarium keratitis:
a case-control study in singapore. Arch Ophthalmol. 2007; 125: 611-617.
54. Clarke DW, Niederkorn JY. The pathophysiology of Acanthamoeba keratitis. Trends Parasitol. 2006; 22: 175-180.
55. Aksozek A, McClellan K, Howard K, et al.
Resistance of Acanthamoeba castellanii cysts
to physical, chemical and radiological conditions. J Parasitol 2002;88:621-23.
56. Kobayashi T, Higuchi-Watanabe N,
Shiraishi A, et al. Miraflow, Soft Contact Lens
Cleaner: Activity Against Acanthamoeba Spp.
Eye Contact Lens 2015;41:240-4.
57. Padzik M, Chomicz L, Szaflik JP, et al. In
vitro effects of selected contact lens care
solutions on Acanthamoeba castellanii strains
in Poland. Exp Parasitol. 2014;145 Suppl:S98-S101.
58. Iovieno A, Ledee DR, Miller D, Alfonso EC.
Detection of bacterial endosymbionts in clinical Acanthamoeba isolates. Ophthalmology
2010;117:445-452, e441-443.
59. Siddiqui R, Khan NA. War of the microbial
worlds: who is the beneficiary in Acanthamoeba-bacterial interactions? Exp Parasitol. 2012;
130: 311-313.
60. Giraldez MJ, Resua CG, Lira M, et al.
Contact lens hydrophobicity and roughness
effects on bacterial adhesion. Optom Vis Sci.
2010;87:e426-31.
61. Bruinsma GM, van der Mei HC, Busscher
HJ. Bacterial adhesion to surface hydrophilic
and hydrophobic contact lenses. Biomaterials.
2001;22:3217-24.
62. Butrus SI, Klotz SA. Contact lens surface
deposits increase the adhesion of Pseudomonas aeruginosa. Curr Eye Res. 1990;9:717-24.
63. Kodjikian L, Casoli-Bergeron E, Malet F, et
al. Bacterial adhesion to conventional hydrogel and new silicone-hydrogel contact lens
materials. Graefes Arch Clin Exp Ophthalmol.
2008;246:267-73.
64. Shoff ME, Eydelman MB. Strategies to
optimize conditions for testing multipurpose
contact lens solution efficacy against Acanthamoeba. Eye Contact Lens 2012;38:363-7.
65. Kilvington S, Lam A. Development of
standardized methods for assessing biocidal
efficacy of contact lens care solutions against
Acanthamoeba trophozoites and cysts. Invest
Ophthalmol Vis. 2013 Jul;54(7):4527-37.
66. Stapleton F, Stretton S, Papas E, et al. Silicone hydrogel contact lenses and the ocular
surface. Ocular Surface. 2006:24-43.
67. Orsborn G, Venkatesh S. Contact lens
maintenance: lens care solutions and compliance. In. Mivision, 2012.
68. Hui A, Boone A, Jones L. Uptake and
release of ciprofloxacin-HCl from conventional
and silicone hydrogel contact lens materials.
Eye Contact Lens 2008;34:266-71.
69. Tian X, Iwatsu M, Sado K, Kanai A. Studies
on the uptake and release of fluoroquinolones by disposable contact lenses. CLAO J
2001;27:216-20.
70. Karlgard CC, Wong NS, Jones LW, Moresoli
C. In vitro uptake and release studies of ocular
pharmaceutical agents by silicon-containing
and p-HEMA hydrogel contact lens materials.
Int J Pharm 2003; 257: 141-51.
71. FDA. US. Ophthalmic Devices Panel Meeting [online transcript]. In: HEALTH CFDAR,
COMMITTEE MDA eds, 2014.
72. Powell CH, Lally JM, Hoong LD, et al. Lipophilic versus hydrodynamic modes of uptake
and release by contact lenses of active entities
used in multipurpose solutions. Cont Lens
Anterior Eye. 2010;33:9-18.
73. Jones L, Macdougall N, Sorbara GL. Asymptomatic corneal staining associated with
the use of balafilcon silicone-hydrogel contact
lenses disinfected with a polyaminopropyl
biguanide-preserved care regimen. Optom Vis
Sci. 2002;79:753-61.
74. Carnt N, Jalbert I, Stretton S, et al. Solution
toxicity in soft contact lens daily wear is associated with corneal inflammation. Optom Vis
Sci. 2007;84:309-15.
75. Andrasko G, Ryen K. Corneal staining and
comfort observed with traditional and silicone
hydrogel lenses and multipurpose solution
combinations. Optometry 2008;79:444-54.
76. Rosenthal RA, Sutton SV, Schlech BA.
Review of standard for evaluating the effectiveness of contact lens disinfectants. PDA J
Pharm Sci Technol. 2002;56:37-50.
1/27/16 4:18 PM
(COPE Approval
Pending)
CE TEST ~ FEBRUARY 2016
1. Under FDA criteria, for contact lenses to be designated as being ionic, the
pH must fall between:
a. 6.0 and 8.0.
b. 5.0 and 7.0.
c. Anything lower than tear film pH.
d. There is no pH requirement for “ionic” designation at FDA.
12. The role of the preservative in contact lens solutions is which of the following?
a. Disinfecting a lens.
b. Inhibiting contamination of the MPS solution when used for prolonged
periods of time.
c. Serving as a natural buffer for the tear film.
d. A and B are correct.
2. Preservative uptake and release by contact lenses is influenced by all of the
following except:
a. The type of preservative in the MPS used to disinfect lenses.
b. The pore size and water content of the lens material worn.
c. The contact lens case used for storage.
d. All of the above influence preservative uptake and release.
13. Microbial susceptibility to various disinfectants is influenced by which of the
following?
a. Microbial strain.
b. Level of bioburden.
c. Microbial phenotype.
d. All of the above are correct.
3. Which of the following is a contact lens solution-related compliance
concern?
a. Wearing lenses beyond the recommended wearing time.
b. Washing hands before handling lenses.
c. Topping-off or re-using MPS.
d. B and C are correct.
14. Acanthamoeba has a significant ability to survive when challenged by
disinfection. Which of the following are accurate statements relating to
Acanthamoeba and solution disinfection?
a. Acanthamoeba has an innate ability to regulate its pH by osmotic means to
survive when exposed to MPS.
b. Acanthamoebae can encyst when challenged by cell crowding, reduced pH
and sometimes even MPS exposure.
c. Only Acanthamoeba cysts infect corneal tissue, so it doesn’t matter that
they can survive when exposed to MPS.
d. Pre-cystic Acanthamoebae are much easier to kill than trophozoites with
MPS.
4. The FDA will most likely do the following in the next guidance document
revision:
a. Add “real world” testing measures such as organic soil.
b. Add the number of days a lens can be worn for extended or continuous wear.
c. Add Acanthamoeba and possibly other organisms to the test panel.
d. A and C are correct.
5. Biofilms allow various organisms to communicate with one another. The main
concern regarding biofilms is that they:
a. Hinder disinfecting solution efficacy.
b. Promote human corneal epithelial apoptosis.
c. Decrease tear film pH, thereby decreasing all-day lens comfort.
d. Increase the metabolism of resident bacteria, making the strain more
resistant to treatment.
6. In the FDA guidelines for Stand-alone Testing, the log reduction
requirement for Acanthamoeba is:
a. 3 log reduction.
b. 1 log reduction.
c. 4 log reduction.
d. There is no requirement for Acanthamoeba in the Stand-alone Test series.
7. Which of the following is not a documented risk factor for Acanthamoeba
keratitis?
a. Topping off or re-using solutions.
b. Swimming or showering in contact lenses.
c. Being an adapted/veteran lens wearer.
d. Forgetting to rub lenses after removal.
8. Buffers in contact lens solutions are used for which of the following?
a. Maintaining the desired pH of the solution.
b. Removing deposits and bacterial load.
c. Binding proteins.
9. Which of the following best describes the rate of Acanthamoeba keratitis
incidence following the 2007 MPS solution recall?
a. The rate steadily decreased after 2009 as a result of the recall.
b. The rate initially decreased after the recall to the recalled solution prelaunch level, but has increased beyond that point since 2009.
c. No outbreak was noted prior to 2007, so this question is not appropriate.
d. The rate remained the same until today as it was in 2007.
15. Alternatives to using water with GP lenses include all of the following, except:
a. Only fit patients with scleral lenses, obviating the need to use tap water
when inserting GP lenses.
b. Use sterile hospital or inhalation saline (0.9%) as a rinse.
c. Rinse the cleaner off with MPS and insert directly from an approved
conditioning solution.
d. A and B are correct.
16. The Fusarium keratitis outbreak of 2006 resulted in a voluntary solution
recall. Which of the following related statements are accurate?
a. The strain of Fusarium responsible for the outbreak was from Group IV and
did not relate to any water vector.
b. Re-use of this solution reduced the recalled MPS’s biocidal efficacy and was
sequestered over time, posing increased risk to the patient.
c. The isolates evaluated were clonal, and related infections were probably due
to contamination that occurred at the manufacturing plant.
d. The rate of infection was extremely high compared with the 2007
Acanthamoeba outbreak.
17. In addition to organic soil, which factor may ultimately contribute to
infection and reduced MPS efficacy?
a. Wearing of lenses overnight while taking aspirin.
b. Use of certain brands of artificial tears while wearing contact lenses.
c. Running of a marathon while wearing lenses.
d. Use of certain brands of facial moisturizers.
18. Which of the following material properties is not important in classification
of silicone hydrogels?
a. Water content.
b. Ionicity.
c. Surface treatment (i.e., wettability, deposition characteristics).
d. All are important factors to consider when classifying these lenses, since
they are uniquely different than conventional hydrogel lenses.
10. Silicone hydrogels differ from conventional hydrogel lenses by which of the
following characteristics?
a. Ionic charge.
b. Hydrophobicity.
c. Material pore size.
19. Which of the following statements on testing MPS efficacy against protozoa
are true?
a. Infection rates are so low that it’s impossible to determine the species
responsible for most infections.
b. It’s uncertain as to what inoculum size is ideal for testing, since we don’t
have data that translates easily to infection potential.
c. Axenic growth of Acanthamoeba with a certain number of passes will show
different resistance patterns to MPS than those organisms that are not
“bacterized.”
d. B and C are true.
11. The FDA panel of organisms in Stand-alone Testing (Primary Criteria) includes
all of the following, except:
a. Pseudomonas aeruginosa.
b. Serratia marcescens.
c. Acanthamoeba castellani.
d. Fusarium solani.
20. Which of the following is true regarding the Regimen Test (ISO18259)?
a. It’s generally considered a more stringent test than the secondary criteria of
the Stand-alone Test.
b. It does not require using a rub and rinse phase.
c. It uses a designated log cut-off.
d. It includes Acanthamoeba in its panel of organisms tested.
1/27/16 4:18 PM
EXAMINATION ANSWER SHEET
Reality Check: How FDA Testing Falls Short
Valid for credit through February 1, 2019
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.
Go Further
Without Leaving
Home
Payment: Remit $35 with this exam. Make check payable to Jobson Medical
Information LLC.
Credit: COPE approval for 2 hours 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.
Answers to CE exam:
6. A
1. A B C D
2. A B C D
7. A
3. A B C D
8. A
4. A B C D
9. A
5. A B C D
10. A
B C
D
B C
D
B C
D
B C
D
B C
D
11.
12.
13.
14.
15.
A
B C
D
A
B C
D
A
B C
D
A
B C
D
A
B C
D
16.
17.
18.
19.
20.
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
21. Met the goals of the statement:
22. Related to your practice needs:
1
2
3
4
5
23. Will help improve patient care:
1
2
3
4
5
24. Avoided commercial bias/influence:
1
2
3
4
5
25. How do you rate the overall quality of the material? 1
2
3
4
5
26. Your knowledge of the subject increased: Greatly
Somewhat
Little
27. The difficulty of the course was:
Complex Appropriate Basic
28. How long did it take to complete this course?
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LESSON 112268, RO-RCCL-0216
RCCL
REVIEW OF CORNEA
& CONTACT LENSES
1/27/16 4:18 PM
The GP Experts
By Robert Ensley, OD, and Heidi Miller, OD
Good Chemistry
Are you up to date on pairing GP lenses and solutions? Here’s a look at what makes a
perfect match.
G
as permeable (GP)
contact lens performance is highly
dependent on the
quality of the lens
surface. A clean, wettable lens
allows for both a higher degree of
vision clarity and better patient
comfort. Accordingly, proper care
of GP lenses is instrumental in
ensuring successful wear.
With the variety of cleaning
products available, however, it’s
no wonder many patients become
confused regarding which solutions to use. To help differentiate,
let’s take a moment to review
the fundamental components of
successful GP lens care: surface
cleaning and disinfection.
SURFACE CLEANING
Early GP lenses were manufactured with silicone/acrylate copolymers to increase oxygen permeability, resulting in negatively
charged hydrophobic lens surfaces
that attract positively-charged proteins and lipids. Modern GP lenses
added fluorine (fluorosilicone/
acrylate) to the mix, resulting in a
lower surface tension that reduces
deposit adherence and increases
surface wettability for greater ease
of lens cleaning.1
Most GP cleaners incorporate
surfactants, compound molecules
with a hydrophilic head and
hydrophobic tail that surround
lens contaminants like proteins,
lipids and cosmetic-related debris
to form a micelle. This molecule
is then solubilized in solution and
rinsed away in combination with
digital pressure and friction.
GP cleaners that contain abrasive surfactants like the Original
Formula Boston Cleaner (Bausch +
Lomb) and the now-discontinued
Opti-Clean II (Alcon) are traditionally more effective when used
with lower-Dk, early-generation
GP lenses that bind more protein.
Newer cleaners including Boston
Advance Cleaner (Bausch + Lomb)
and Opti-Free Daily Cleaner
(Alcon) use smaller-diameter abrasive particles; however, these are
still classified as mildly abrasive
and should be used with caution
on higher Dk GP lenses, as they
can scratch the surface and induce
minus power to the lens by reducing center thickness.2 Abrasive
cleaners are also contraindicated
for use with any GP lens that is
plasma treated. If a non-abrasive
daily cleaner is required, Optimum
Extra Strength Cleaner (Lobob
Laboratories), a preservative-free
formula, can be used.
Other daily cleaners include the
isopropyl alcohol-based Sereine
Extra Strength Cleaner (Optikem
International) and Walgreens
Extra Strength Daily Cleaner.
Both contain the same ingredients
as the MiraFlow (Alcon) daily
cleaner that was discontinued in
2010. Note, the original MiraFlow
formulation was recently purchased by an independent practitioner and is distributed online
only through a direct-to-consumer
website.
Patients who are heavy protein
depositors may benefit from an
additional enzymatic or solvent
cleaner that can be used periodically. Current enzymatic cleaners
come in liquid form, allowing
them to be added directly to a
storage solution. Boston One-Step
Enzymatic Cleaner (Bausch +
Lomb) is recommended for weekly
use, while SupraClens Daily
Cleaner (Alcon) is recommended
for every day use.
Formerly an in-office cleaner
only, Progent (Menicon) incorporates a mixture of sodium hypochlorite and potassium bromide
to remove proteins and is recommended for use on a biweekly
basis. Because this formulation
What is Plasma Treating?
Plasma is a gas that is ionized into a mixture of highly reactive negatively and positively charged particles. During treatment, GP lenses
are placed in a vacuum chamber, where oxygen plasma breaks up
and removes surface contaminants including grease, lipids and other
residues. This process improves the lens’ initial wettability and comfort by reducing the wetting angle.
Plasma treating should be thought of as a “deep clean” process
rather than a coating treatment. Lenses with a plasma treatment are
shipped hydrated, so excessive handling should be avoided prior to
dispensing. Although the plasma treatment will wear off over time,
abrasive cleaners are not recommended for use to avoid accelerating the breakdown. Most laboratories recommend cleaning the lens
with Boston Simplus (Bausch + Lomb), Unique pH (Menicon) or a
hydrogen peroxide-based solution.
p38_RCCL0216_PSP_GPE.indd 38
1/27/16 4:17 PM
is essentially bleach, it is recommended only for patients who
fully understand how to use it
properly.
In general, lenses should not
soak in any of these liquids for
more than 30 minutes, to avoid
discoloration. Less frequent use of
an enzymatic cleaner or Progent
may be sufficient for lenses
containing fluorosilicone/acrylate
materials.
Following use of daily cleaners, GP lenses should be rinsed
thoroughly prior to lens insertion.
While many GP wearers rinse with
tap water, this is controversial. To
reduce the risk of microbial exposure, rinsing with a sterile saline or
multipurpose solution is typically
recommended.
DISINFECTION
AND STORAGE
Once the lens surface has been
cleaned, a GP lens should be
soaked overnight. Depending on
the storage method, the lens is disinfected using either preservatives
or hydrogen peroxide. There are
several preservatives used in GP
solutions that are either bactericidal or bacteriostatic in nature.
These typically have larger molecular weights, limiting their ability
to bind to a GP lens. Common
preservatives include clorhexidine
gluconate, benzyl alcohol, polyquaternarium-1 (polyquad) and
biguanides.
The Boston Conditioning
Solution and Boston Advance
Formula Conditioning Solution
(Bausch + Lomb) are both packaged independently, but are part
Deposits on a hybrid contact lens.
of a two-bottle system with their
daily-cleaning counterparts. Both
solutions use clorhexidine gluconate 0.003% as a preservative,
and contain polyvinyl alcohol
(PVA) and a cellulosic viscosifier
to coat the lens surface, providing
both moisture and a cushioning
effect for added comfort. The
Advance Formula Solution has an
added preservative, polyaminopropyl biguanide 0.0005% (PAPB),
and derivatized polyethylene glycol as an additional wetting agent.
Other solution options for
cleaning, disinfecting and storage
(CDS) include Optimum CDS
(Lobob) and MeniCare CDS
(Menicon). Both solutions use
the same formulation with lauryl
sulfate salt of imidazoline and
octylphenoxypolyethoxyethanol to
clean the lens, and are preserved
with benzyl alcohol 0.3% and
edetate disodium 0.5%. Both CDS
solutions recommend a rub and
rinse prior to overnight soak, and
should be thoroughly rinsed prior
to lens insertion. Optimum CDS
can be purchased independently or
as part of a combined care system
kit with the Optimum ESC and
Optimum wetting/rewetting drops.
If a patient develops a preservative sensitivity, hydrogen
peroxide-based solutions can be
used as an alternative. Solutions
containing a 3% hydrogen peroxide concentration are particularly effective against multiple
pathogens, including bacteria,
viruses, fungi and protozoa, as
peroxide produces free radicals
that can penetrate a microbe’s cell
membrane and destroy its DNA.
However, the solution’s pH of
4.0 means that a neutralization
step is also required prior to lens
placement on the ocular surface.
Additionally, because hydrogen
peroxide cannot penetrate the
matrix of GP lens, as it can a soft
hydrogel, GP lenses still require a
(Continued on page 41)
39
1/27/16 4:17 PM
Pharma Science & Practice
By Elyse L. Chaglasian, OD, and Tammy Than, MS, OD
Dextenza on Deck
Could the latest approach to steroid therapy conquer noncompliance once and for all?
T
opical medication compliance is an ongoing
struggle for many optometric practices today.
Patients report issues
with frequency of administration,
cost of medication and associated
side effects of instillation (e.g.,
stinging, hyperemia), while practitioners struggle with lack of patient
adherence. Since the process of
ensuring medications are adequately taken can be frustrating for all
those involved, researchers continue to search for newer and better
ways to deliver therapeutic doses of
medicine via simpler methods.
Dextenza (sustained-release
dexamethasone 0.4mg, Ocular
Therapeutix) aims to provide a
new way to deliver steroid therapy.
Rather than administering a drop
or injection, an intracanalicular
depot is inserted into the puncta
to provide a one-month tapered
release of preservative-free medication to the ocular surface. At
the end of 30 days, the biodegradable hydrogel depot is absorbed
by the body, eliminating the need
for removal. Ocular Therapeutix
is evaluating the use of Dextenza
in various conditions, including
allergic conjunctivitis, postoperative pain and inflammation, and
inflammatory-related dry eye.
Below, let’s examine these conditions individually.
ALLERGIC CONJUNCTIVITIS
The initial Phase III clinical trial for
Dextenza in the fall of 2015 yielded
mixed results. While it did meet the
primary endpoint of relieving ocular itching from allergic conjunctivitis (p<0.0001), it did not achieve
the secondary endpoint of relieving
conjunctival redness. Still, the drug
was qualified as safe and well-tolerated. Researchers have since revised
the protocol for a second, Phase III
multicenter, 1:1 randomized, double-masked, vehicle-controlled trial,
where the sole primary endpoint
will be a reduction in ocular itching
by day seven following insertion.
ications were required by a smaller number of Dextenza subjects
(20.7% vs. 72.4%) compared with
the number of placebo subjects at
days 14 and 30; the Dextenza subjects also exhibited fewer adverse
events (13.8% vs. 43.8%).
Unfortunately, the 240-patient
Phase III trial failed to meet the
primary endpoint for reduction
“AN INTRACANALICULAR
DEPOT IS INSERTED INTO
THE PUNCTA TO PROVIDE
ONE-MONTH TAPERED
RELEASE OF MEDICATION.”
POST-OP OCULAR PAIN
Ocular Therapeutix received acceptance for a New Drug Application
(NDA) from the FDA for the
treatment of ocular pain following
ophthalmic surgery, based on data
from a single Phase II and two
Phase III clinical trials—the latter
of which achieved the primary
endpoint of reduction of ocular
pain but not the second primary
endpoint of absence of cells in the
anterior chamber.
In the Phase II trial of 247
patients, researchers found statistically significant differences between
the Dextenza-treated group and
placebo for both pain and absence
of cells in the anterior chamber
(p<0.005). All patients retained the
device through day 14, and 97% of
patients retained it through day 30.
No long-term intraocular pressure
spikes were observed. Rescue med-
of ocular inflammation (Dextenza
39.4% vs. placebo 31.3%). A third
Phase III trial aimed at achieving
the same primary endpoint recently
began enrolling patients, and it is
the company’s intention to file a
supplement to the NDA if the study
is successful.
The two prospective, multicenter, randomized parallel-arm,
double-masked, vehicle-controlled
Phase III trials were completed with
a total of 487 patients undergoing
unilateral clear corneal cataract
surgery. Patients were randomized
2:1 to receive either Dextenza or
a placebo vehicle punctal plug. As
stated, the two primary efficacy
endpoints were absence of cells in
the anterior chamber at day 14 and
the absence of pain, subjectively reported on a scale of 0 to 10, at day
eight. Secondary efficacy endpoints
were absence of flare in the anterior
1/27/16 4:17 PM
chamber at each visit and absence
of cells and absence of pain at each
visit, other than the day used for
the primary efficacy measure.
The new Phase III trial expected
to constitute the supplement to the
NDA allows for modifications of
the original protocol, including a
1:1 (rather than 2:1) randomization of patients; the exclusion of
patients undergoing treatment with
high doses of oral NSAIDs; and
improved training and guidance for
on-site clinical investigators regarding adherence to study protocols,
including the appropriate use of
rescue medications.
INFLAMMATORY DRY EYE
At the end of 2015, results from
a Phase II exploratory clinical
trial for the treatment of signs and
symptoms of moderate to severe
dry eye disease were released. The
prospective, randomized, parallel-arm, double masked, vehicle-controlled study included 43
patients (86 eyes) at two sites in the
United States. Patients were initially
treated with a placebo punctal
plug for 45 days; those patients
who benefited were excluded from
the subsequent treatment phase.
Treated patients were randomized
1:1 to receive either Dextenza or a
placebo vehicle for 30 days.
Total corneal staining at day 30
showed the Dextenza group had
statistically significant improvement
at day 30 as compared to placebo
(p=0.018). Subjectively, there was
improvement as measured by the
standard patient evaluation of eye
dryness (SPEED) questionnaire
for dryness, itchiness and scratchiness. There were no intraocular
spikes noted, and there was a 96%
retention rate of the drug depots
throughout the 30-day trial.
W
hile the results from these
trials are mixed, it remains
clear that an alternative method of
drug delivery can be effective for
certain ocular conditions and symptoms. Hopefully, this is the gateway
to further research that will enable
us to offer our patients a cost-effective, safe and easy method to
overcome some common ocular
issues that are undermined not by
pharmaceutical shortcomings but,
rather, human ones.
RCCL
THE GP EXPERTS: GOOD CHEMISTRY
(Continued from page 39)
rubbing step for proper cleaning.
Current peroxide-based solutions
on the market include ClearCare
Plus (Alcon), PeroxiClear (Bausch
+ Lomb), and OxySept UltraCare
Formula (AMO).
MULTIPURPOSE SOLUTIONS
For some patients, cleaning and
disinfecting a GP lens with two
separate solutions can be burdensome or confusing. A multipurpose solution (MPS) may be a
more convenient and appropriate
choice for these patients. Boston
Simplus (Bausch + Lomb) contains the surfactant poloxamine
1107 and hydroxyalkylphosphonate to remove protein deposits,
clorhexidine gluconate and PAPB
preservatives to disinfect the lens,
and glucam-20 and hydroxypropylmethylcellulose (HPMC) for
cushioning and wetting. Product
guidelines recommend that lenses
be removed every night and directly in solution; in the morning,
the lens should be rubbed gently
on either side for 20 to 30 seconds
and rinsed prior to lens insertion.
Unique pH multipurpose solution (Menicon) is the same formulation as the former Opti-Free GP
(Alcon). Preserved with polyquad
and EDTA, Unique pH also contains hydroxypropyl guar, polyethylene glycol, tetronic 1304, boric
acid and propylene glycol to aid
in cushioning and wettability. The
formula also allows the solution
to adjust viscosity based on the
pH of the ocular surface. While
no rinsing is typically required, if
the SupraClens (Alcon) enzyme
is added to the solution, the lens
should be rinsed thoroughly prior
to insertion.
W
ith any lens/solution combination, practitioners
should inform patients regarding
proper use and potential problems
to watch for. Always be sure to
remain up to date on the latest
research to ensure your recommendations are the best option for
your patients.
RCCL
1. Cannella A. Polymer Chemistry. In: Bennett ES,
Weissman BA, ed. Clinical Contact Lens Practice.
4th Ed. Philadelphia, PA: Lippincott, Williams &
Wilkins; 2005: 235-242.
2. Bennett ES, Wagner H. Gas-permeable lens
care and patient education. In: Bennett ES, Henry
VA, ed. Clinical Manual of Contact Lenses. 4th Ed.
Philadelphia, PA: Lippincott, Williams & Wilkins;
2014: 157-186.
41
1/27/16 4:17 PM
Out of the Box
By Gary Gerber, OD
What’s in a Name?
Even the smallest changes in how your staff members present themselves to patients
can have the biggest impact.
R
ecently, an intense
discussion among
our clients occurred
about a seemingly
benign subject—staff
uniforms. Specifically, name tags:
where can they be bought, and
should the practice logo be printed
on them?
As I often do when things
become nitty-gritty, I took a
step back to examine the big
picture of this particular practicebuilding topic. Why would a
practitioner mandate (or not) that
staff wear uniforms and if they
do, why a particular type, style
or color? What about the pros
and cons of using name tags vs.
writing the staff member’s name
in embroidery? Why display
any name at all? And what
about complementary items like
laboratory coats and/or ties?
There is, of course, no universal
answer for these questions—it
depends upon the practice’s model,
mission statement, values, culture
and long-term goals. It is more
than likely, however, that every
practice has one communal thread
tying them all together: they are all
attempting to connect and relate
to patients, which benefits both
the clinical care aspect and the
business as a whole.
So, with respect to the staff dress
code, is there anything that can
be done to help connect with the
patient? Can altering something
so seemingly simple bring about
such an important change as an
increase in patient loyalty? Is there
anything that can be done along
these lines with respect to a staff
dress code? After a recent
visit to a Westin Hotel, I
believe the answer to this
question is, in fact, yes.
NICE TO MEET YOU
Her name tag read: My
name is Shannon. My
passion is cooking. Though
I’m not a foodie and I only
have a limited interest in
ght
cooking, this simple line caught
my attention. In effect, it brought
to the forefront the woman’s
individuality and gave me the
feeling that if I had a problem
during my stay, I could rely on her
to help me resolve it more so than
someone else. And if I didn’t have
a problem, I would still have an
“insider” at this particular hotel
the next time I came.
During my short stay, I learned
about other employees at the
hotel with passions that varied
from sports and travel to film. I
developed an underlying feeling
that during staff meetings, the
presentation likely began with the
maintenance engineer taking about
his weekend gardening project,
rather than the upcoming elevator
closure schedule, and I also
thought that during a particular
grinding and challenging work
day, an employee touching base
with a returning guest who
recognized them and remembered
the employee’s daughter’s soccer
team, helped that employee get
through the day a little easier.
See what that simple name tag
did? I was already thinking about
my next stay as if it was a given.
In effect, that simple name tag
change led to a better
connection between an employee
and a guest, a better sense of
teamwork among employees and
a better overall mood in the work
environment. These are the real
reasons for the Westin’s name tag
technique—reasons that can easily
be applied in the context of an
optometry practice.
So, the next time you have to
make a business decision, no
matter how seemingly small—
what is smaller than a name tag,
anyway?—make it in the context
of looking at the bigger picture.
Ask yourself, “Why am I doing
this, what are its long-term
benefits and how is it going to
support my practice mission and
values?”As is often the case, and
as you saw with the name tags,
these decisions are rarely obvious
and take some creativity. If you’re
a self-employed decision-maker
reading this, don’t worry about
the immediate repercussions.
Adding a name tag is a simple and
inexpensive change. Just go with it
and see what happens.
And the next time you see me,
my tag will say, “My name is Gary
Gerber. My passion is helping
optometrists succeed.”
RCCL
p42_RCCL0216_OTB.indd 42
1/27/16 12:15 PM
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cleaning and disinfection of CLEAR CARE® – and now with our exclusive
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PERFORMANCE DRIVEN BY SCIENCE
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1
Gabriel M, Bartell J, Walters R, et al. Biocidal efficacy of a new hydrogen peroxide contact lens care system against bacteria, fungi, and Acanthamoeba species.
Optom Vis Sci. 2014; 91: E-abstract 145192. © 2015 Novartis 5/15 CCS15069AD-B
RCCL0216_Alcon Clear Care.indd 1
1/21/16 3:21 PM
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RCCL0315_Menicon.indd 1
2/23/15 11:15 AM

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