contact lens spectrum lens spectrum a proud supporter of body stock only group publisher, optometric...

Contact LensSPECTRUM

S P E C I A L E D I T I O N 2 0 1 3

®

www.clspectrum.com

THE WORLD’S FIRST AND ONLY

Water Gradient Contact Lens

ALSO IN THIS ISSUE

■ The Effects of Friction and Lubricity on Comfort

■ Introducing Water Gradient Technology

■ Overcoming Contact Lens Compromise

A fundamentally new approach led to breakthrough technology,

ushering in a new era in comfort.

A new lens has arrived that’s going to change everything.

A scientific breakthrough

10 years in the making.

© 2013 Novartis 12/12 DAL13046JADSee product instructions for complete wear, care and safety information.

Contact Lens Spectrum 6/13

82413 DAL13046JAD CLS.indd 1 5/22/13 3:27 PM

F E A T U R E SThe Shifting Prescribing ParadigmBy Jason J . Nichols , OD, MPH, PhDLearn why so many practitioners now choosedaily disposables as their go-to lenses.

Dealing With DiscomfortBy Caroline A. Blackie, OD, PhD, FAAO, Donald R. Korb,OD,FAAO, and Kelly Nichols, OD, MPH, PhD, FAAO, Dipl PHAn in-depth look at the epidemiology, diagnosis andtreatment of contact lens-related dryness.

Clinical Relevance of Contact Lens LubricityBy Desmond Fonn, MOptom, FAAOUsing science to provide better comfort for CL wearers.

Measuring Friction and Lubricity of Soft Contact Lenses: A ReviewBy Lakshman N. Subbaraman, PhD, BSOptom, MSc, FAAOand Lyndon W. Jones, PhD, FCOptom, FAAOComfort may be tied to friction and lubricity.

Introducing Water Gradient TechnologyBy Ralph Stone, PhDDaily disposable contact lenses with water gradienttechnology represent a new era in contact lens wear.

The Development of Dailies Total1 Water Gradient Contact LensesBy John Prui t t , PhD and Er ich Bauman, OD, FAAO Research led to a departure from using a single bulkmaterial for the whole lens.

Groundbreaking Technology Debuts in DailyDisposable MarketPanelists discuss a unique new lens that has surprisingcharacteristics designed to defeat discomfort.

Special Edition2 0 1 3

1419

2528

3440

46

V O L U M E 2 8 N U M B E R 1 3

®


Editor’s PerspectiveBy Jason J. Nichols, OD, MPH, PhD, FAAODaily Disposable PrescribingFinally Begins to Trend Up

Research ReviewBy Eric Papas, PhD, MCOptom, DipCLClose to the Edge: Oxygen atthe Lens Periphery

Prescribing for PresbyopiaBy Thomas G. Quinn, OD, MSDaily Disposables: ProblemSolver for the Presbyope

Contact Lens Design &MaterialBy Neil Pence, OD, FAAONovel Water Gradient LensMaterial

Dry Eye Dx and TxBy William Townsend, OD, FAAOHow Daily Disposable Lenses CanAddress Contact Lens Dryness

Contact Lens Care &ComplianceBy Susan J. Gromacki, OD, MS, FAAOCompliance With DailyDisposable Contact Lenses

Contact Lens Practice PearlsBy Jason Miller, OD, MBA, FAAOSetting the Stage for DailyDisposable Contact Lenses

The Business of ContactLensesBy Gary Gerber, ODWinning the Race

Pediatric and Teen CL CareBy Christine W. Sindt, OD, FAAOWhy Daily Disposable LensesMake Sense for Children

Treatment PlanBy William L. Miller, OD, PhD, FAAOContact Lens Discomfort: CanPast Workshops Provide Insight?

5

6

10

11

12

13

53

54

55

56

D E P A R T M E N T S

END-OF-DAY

9.2 OUT OF 10

COMFORT

Time of0.0%

50%

100%

Insertion Time of Removal (average 14 hours)

100% 100%

9.2 OUT OF 10

COMFORT

Time of0.0%

50%

100%


100% 100%

PERFORMANCE DRIVEN BY SCIENCETM

THIS IS WHY contact lenses have reached a new era in comfort.DAILIES TOTAL1® Water Gradient Contact Lenses feature an increase from 33% to over 80% water content from core to surface* for the highest oxygen transmissibility, and lasting lubricity for exceptional end-of-day comfort.1, 2, 3

The First And Only Water Gradient Contact Lens

Let your customers experience the DAILIES TOTAL1® contact lens difference today.

UNIQUE WATER GRADIENT

>80%33%>80%

WATER CONTENT (%)

*In vitro measurement of unworn lenses.1. Based on the ratio of lens oxygen transmissibilities among daily disposable contact lenses. Alcon data on fi le, 2010.2. Based on critical coeffi cient of friction measured by inclined plate method; signifi cance demonstrated at the 0.05 level. Alcon data on fi le, 2011.3. In a randomized, subject-masked clinical study, n=40. Alcon data on fi le, 2011.4. Angelini TE, Nixon RM, Dunn AC, et al. Viscoelasticity and mesh-size at the surface of hydrogels characterized with microrheology. ARVO 2013;E-abstract 500, B0137.

See product instructions for complete wear, care and safety information. © 2013 Novartis 04/13 DAL13097JAD

Ultrasoft, hydrophilic surface gel approaches 100% water at the outermost surface for exceptional lubricity4

LASTING LUBRICITY

Features different surface and core water contents, optimizing both surface and core properties2


Enlarged Water GradientContact Lens Cross-Section

Lasting lubricity for exceptional comfort from beginning to end of day3

OUTSTANDING COMFORT

~100%33% >80%>80%



®


A Proud Supporter of

Body stock only

GROUP PUBLISHER, OPTOMETRIC PUBLICATIONSRoger Zimmer(203) 846-2827 • [email protected]

ADVERTISING SALESDawn Schaefer, Eastern Region(267) 373-9798 • [email protected]

Scott Schmidt, Eastern Region(610) 564-7237 • [email protected]

Ed Meagher, Western Region(415) 435-3217 • [email protected]

Audrey Krenzel, Classified/Resource Center Advertising and Reprints(215) 367-2184 • [email protected]

E-MEDIA SALESRob Verna, National Account Manager(215) 367-2179 • [email protected]

PRODUCTION DIRECTOR Sandra Kaden

ART DIRECTOR Kimberly Macheski

CONTRIBUTING ART DIRECTOR Candice Kent

PRODUCTION MANAGER Bill Hallman(215) 628-6585 • [email protected]

EDITOR-IN-CHIEFJason J. Nichols, OD, MPH, PhD, FAAO

2008-Present

CLINICAL FEATURES EDITOREdward S. Bennett, OD, MSEd, FAAO

2007-Present

MANAGING EDITORLisa Starcher

(215) 367-2168 • [email protected]

ASSISTANT EDITORAndy Myer

SPECIAL PROJECTSEDITORIAL DIRECTOR Angela Jackson

(215) 316-9113 • [email protected]

EDITOR/PROJECT MANAGER Leslie Goldberg

FOUNDING EDITORNeal J. Bailey, OD, PhD

1986-1987

EDITORS EMERITUSJoseph T. Barr, OD, MS, FAAO

1987-2007

Carla J. Mack, OD, MBA, FAAO2007-2008

COLUMNISTS

Online Photo DiagnosisMark André, FAAO

Patrick J. Caroline, FAAOGregory W. DeNaeyer, OD, FAAOWilliam Townsend, OD, FAAO

Research ReviewEric Papas, PhD, MCOptom, DipCL FAAO

Loretta B. Szczotka-Flynn, OD, PhD, MS, FAAO

Refractive FocusDavid W. Berntsen, OD, FAAO

Jason Marsack, PhD

Prescribing for Presbyopia/AstigmatismTimothy B. Edrington, OD, MS, FAAO

Craig W. Norman, FCLSAThomas G. Quinn, OD, MS, FAAO

GP InsightsEdward S. Bennett, OD, MSEd, FAAOGregory W. DeNaeyer, OD, FAAO

Contact Lens Design & MaterialsNeil Pence, OD, FAAO

Ronald K. Watanabe, OD, FAAO

Dry Eye Dx and TxAmber Gaume Giannoni, OD, FAAO

Katherine M. Mastrota, MS, OD, FAAOWilliam Townsend, OD, FAAO

Contact Lens Care & ComplianceSusan J. Gromacki, OD, MS, FAAOMichael A. Ward, MMSc, FAAO

Contact Lens Practice PearlsJohn Mark Jackson, OD, MS, FAAOJason R. Miller, OD, MBA, FAAOGregory J. Nixon, OD, FAAO

The Business of Contact LensesGary Gerber, OD

Clarke D. Newman, OD, FAAO

Pediatric and Teen CL CareMary Lou French, OD, MEd, FAAOChristine W. Sindt, OD, FAAO

Treatment PlanWilliam Miller, OD, PhD, FAAO

Leo Semes, OD, FAAO

Contact Lens Case ReportsMark P. André, FAAO

Patrick J. Caroline, FAAO

SUBSCRIPTION INFORMATION: P.O. Box 3078

Northbrook, IL 60065(800) 306-6332 • Fax (847) 564-9453

E-mail: [email protected] page: www.clspectrum.com

PROMOTIONAL EVENTS MANAGER Michelle Kieffer

CIRCULATION MANAGER Carrie Eisenhandler

EDITORIAL, PRODUCTION, AND SALES OFFICES:PentaVision LLC323 Norristown Road, Suite 200Ambler, PA 19002Phone: (215) 646-8700

PENTAVISION CONFERENCE GROUPMaureen Platt • (215) [email protected]

PENTAVISION LLC

PRESIDENT Thomas J. Wilson

EXECUTIVE VICE PRESIDENTS Mark Durrick, Douglas Parry, Robert Verna, Roger Zimmer

KEEP UP WITH INDUSTRY NEWSbetween issues of Contact LensSpectrum by subscribing to our e-mailnewsletter, Contact Lenses Today. Visit www.cltoday.com or the CLS site(www.clspectrum.com) to subscribe.

Visitwww.clspectrum.com for complimentary access to the

digital version of the 2013 Special Edition of Contact Lens Spectrum.

CLSon the webNeed More Information?

Go beyond the pages and visit us online.Searchable Article ArchivesThis Month’s Features

Breaking NewsDigital Supplements & VideosUpcoming Events/Seminars

Annual Contact Lenses & Solutions SummarySubscription InformationOnline Photo Diagnosiswww.clspectrum.com

An interactive extension of the leadingclinical contact lens information source.

END-OF-DAY

9.2 OUT OF 10

COMFORT

Time of0.0%

50%

100%


100% 100%

Prior to0.0%

50%

Insertion Time of

PER

CEN

T O

F LU

BR

ICIT

Y F

AC

TOR

Removal

100%

~100%33% >80%>80%

Let your patients experience the DAILIES TOTAL1® contact lens difference today.


Lens maintains 100% of its initial lubricity even after a day of wear1

100% LUBRICITY MAINTAINED

Ultrasoft, hydrophilic surface gel approaches 100% water at the outermost surface6 for exceptional lubricity

LASTING LUBRICITY



The First and Only Water Gradient Contact Lens


THIS IS WHY lasting lubricity means lasting comfort.DAILIES TOTAL1® Water Gradient Contact Lenses maintain 100% of their lubricity after a day of wear.1 And because lubricity is highly predictive of contact lens comfort, lasting lubricity means lasting comfort.2, 3, 4

PERFORMANCE DRIVEN BY SCIENCE™

1. Alcon data on fi le, 2011.2. Brennan N. Contact lens-based correlates of soft lens wearing comfort. Optom Vis Sci. 2009;86:E-abstract 90957.3. Coles CML, Brennan NA. Coeffi cient of friction and soft contact lens comfort. American Academy of Optometry. 2012;E-abstract 125603.4. Kern JR, Rappon JM, Bauman E, Vaughn B. Assessment of the relationship between contact lens coeffi cient of friction and subject lens comfort. ARVO 2013;E-abstract 494, B0131.5. Thekveli S, Qiu Y, Kapoor Y, Kumi A, Liang W, Pruitt J. Structure-property relationship of delefi lcon A lenses. Cont Lens Anterior Eye. 2012;35(suppl 1):e14.6. Angelini TE, Nixon RM, Dunn AC, et al. Viscoelasticity and mesh-size at the surface of hydrogels characterized with microrheology. ARVO 2013;E-abstract 500, B0137.

See product instructions for complete wear, care, and safety information. © 2013 Novartis 6/13 DAL13224JAD

>80%33%>80%

WATER CONTENT (%)

Contact Lens Sp

ectrum 13th SE

82411 DAL13224JAD CLS.indd 1 5/31/13 10:18 AM

ADaily DisposablePrescribing FinallyBegins to Trend Up

B Y J A S O N J . N I C H O L S , O D , M P H , P H D , F A A O

editor’s perspective

s noted in our annual report for 2012, published in the January 2013 edition ofContact Lens Spectrum, the daily disposable segment of the contact lens market wasthe segment of the contact lens market associated with the most growth for thesecond year running. This is indeed exciting news, particularly as the United Statesmarket has lagged behind other worldwide markets for many years in terms of dailydisposable prescribing trends. It seems that practitioners here are beginning to embrace the notion that daily disposables are associated with the best comfort,convenience and ocular health in terms of the individual contact lens-wearing experience.

As you will note in this Special Edition of Contact Lens Spectrum, we are on theverge of seeing an even greater revolution in the daily disposable segment of themarket. Innovation, rather than incremental advances in product development, iswhat drives market-leading advances and adoption of new ideas and technologies.As you will see in this issue of Contact Lens Spectrum, we are now seeing an entirelynew material technology being used in the daily disposable platform. It’s only to beanticipated that new technologies such as this will further drive trends we observein clinical practice. We hope you enjoy this Special Edition on daily disposablecontact lenses and associated new material technologies as you consider adoptingnew prescribing trends in your practice.

w w w . c l s p e c t r u m . c o m C O N T A C T L E N S S P E C T R U M / S P E C I A L E D I T I O N 2 0 1 3 • 5

B Y E R I C P A P A S , P H D , M C O P T O M , D I P C L

Research Review

faded into the background in recent years, but should we forgetabout the issue altogether? In asilicone hydrogel world wheredaily wear is the dominant modality, and — apart fromblinking — there is no eye clo-sure during lens wear, are therestill risks?

Measuring Dk/t: Location Matters

Manufacturers specify theDk/t of their contact lens materi-als based on measurements takenat the center of a representativelens, usually a lens with a nominalback vertex power of –3.00D. Forany prescribed lens, however, thethickness profile can vary signifi-cantly from the center to the pe-riphery, depending on the designand the back vertex power. Evenfor a –3.00D spherical lens, thethickness can be 2 or 3 timesgreater at some positions outsidethe center.

Because the Dk/t of a lens isgoverned by its thickness, weneed to pay closest attention tothe regions of the ocular surfacecovered by the thickest portionsof the lens. For most modernlenses with diameters of 13.5 mmto 14.5 mm, the peripheral

cornea and the limbus are likelyto be the main sites under threat.

Corneal Swelling Response to Hypoxia

Perhaps the most commonlystudied response to ocular hypox-ia is corneal swelling. Swelling isless pronounced at the peripheryof the cornea than at the centerbecause anatomical factors pro-gressively limit the extent towhich swelling can occur as weapproach the limbus. For this reason, there is little value inmeasuring the far periphery ofthe cornea, but some studies haveexamined slightly less extreme locations.

One such investigation showedthat certain features of a hydrogellens, such as thickened toric stabi-lization zones, can limit oxygenflow and cause regional and local-ized swelling under daily wearconditions (Tyagi et al, 2010).Another study, which may havemore general application, foundthat after 3 hours of open eyewear, spherical lenses with loweroxygen transmissibility can pro-duce significant peripheralswelling (Morgan et al, 2010).These researchers analyzed theirdata to estimate the minimum

In the days before silicone hydrogel materials be-came available, contact lens practitioners spent agreat deal of time worrying about oxygen trans-missibility (Dk/t). These concerns seem to have

Dk/t needed to avoid peripheralcorneal swelling in daily wear.They calculated a value of 33 x10-9 (cm s-1)(mLO2 mL-1 mmHg) across the entire lens.

Because most practitioners donot routinely use pachometry indaily practice, corneal swelling isnot useful as a clinical indicator ofthe oxygen supply to the corneo-limbal region. The most easily accessible alternative marker is the behavior of the limbal vasculature.

Hyperemia as an Alternate Marker

Blood vessels throughout thebody respond to the level of oxy-gen in their local environment,and those at the limbus are no exception. In the short term, reduced oxygen causes hyper-emia, which is perceived as ocularredness or limbal flush. Althoughthese changes are reversible, pro-longed periods of hyperemia canlead to vascularization of the pe-ripheral cornea, which is a moreserious condition with the poten-tial for permanent consequences.

One of the earliest observa-tions made with what were thenexperimental silicone hydrogellenses was that eyes remainedwhiter-looking (Papas et al,1997). Until then, we believedthat mechanical irritation fromthe lens edge caused the rednesshabitually associated with softlenses. Later experiments usinggoggles filled with different gasmixtures demonstrated that oxy-

Close to the Edge: Oxygen at the Lens Periphery

6 • C O N T A C T L E N S S P E C T R U M / S P E C I A L E D I T I O N 2 0 1 3 w w w . c l s p e c t r u m . c o m

gen is an important factor medi-ating these responses (Papas,2003). In addition, a number ofstudies have confirmed the valueof silicone hydrogels in avoidinglimbal redness (Du Toit et al,2001; Dumbleton et al, 2001;Maldonado-Codina et al, 2004;Brennan et al, 2006; Dumbletonet al, 2006).

From a clinical standpoint, theamount of redness produced by acontact lens is inversely related tothe oxygen transmissibility at itsperiphery (Papas, 1998); howev-er, the minimum transmissibilityrequired to prevent hyperemiafrom occurring remains a subjectof active debate. Thus far, theonly work that has directly ad-dressed this question suggested aDk/t in the lens periphery ofabout 55 x 10-9 (cm s-1)(mLO2mL-1 mm Hg) as a reasonableminimum target for the open eye(Papas, 1998). This research wasconducted more than 15 yearsago at a time when few siliconehydrogel lenses were available, soit is surprising that there hasbeen little activity to update thisvalue.

Silicone Hydrogel and the Redness Response

Of some relevance is a studythat compared the limbal rednessresponses of two silicone hydrogellenses with that of a conventionalhydrogel lens during daily wear(Maldonado-Codina et al, 2004).Although the silicone hydrogellenses were made from materialsof dissimilar oxygen permeability,the results showed that, on aver-age, they caused minimal amountsof redness that were similar inmagnitude to the hyperemia ob-served in the non-lens-wearingcontrol subjects. Eyes wearing theconventional hydrogel lenses weresignificantly redder than those

wearing either of the two sili-cone hydrogel lenses.

Although the researchers inthe 2004 study did not try todetermine a transmissibilitythreshold for limbal redness,their observations were subse-quently interpreted as evidencethat the amount of oxygentransmitted by the silicone hy-drogel lens with the lower Dk/twas sufficient to prevent a vas-cular response in the open eye(Morgan et al, 2010). The peripheral transmissibility of this lens was 36 x 10-9 (cm s-1) (mLO2 mL1 mm Hg),a value that potentially lowers

the transmissibility requirementsomewhat and is similar to thevalue I mentioned earlier forperipheral corneal swelling.

Consider TheseQualifying Issues

Before accepting this conclu-sion regarding minimum oxy-gen transmissibility, however,we should consider two qualify-ing issues. First, this estimate ofoxygen transmissibility (Morganet al, 2010) was made someyears after the original clinicalobservations (Maldonado-Codina et al, 2004) by measur-ing a lens with a power of–3.00D. Lenses in the studyranged from –1.00D to –4.00D,so the single value would nothave equally represented the

experience of all participants.Second, the peripheral thick-

ness measurement for the refer-ence lens in the 2004 study wasmade at a diameter of 8 mm. Although this was appropriate inthe context of the study’s primaryaim, which was to examinecorneal swelling, it does not cor-respond to the area of the lensthat would influence vascularchanges at the limbus. Thus,more data must be accumulated to satisfactorily resolve the uncer-tainty surrounding these numbers.

Regardless of the precise values, it seems clear the open eyeis not immune to the effects of

hypoxia that may occur from acontact lens that has poor oxygen-transmitting properties.Fortunately, clinicians can avoidthis problem by choosing care-fully from the array of contempo-rary lenses that are available. CLS

For references, please visitwww.clspectrum.com/references.aspand click on document SE2013.

Associate Professor Papas is executive directorof Research & Development, Brien Holden Vi-sion Institute and Vision Cooperative ResearchCentre, and senior visiting fellow, School ofOptometry & Vision Science, University of NewSouth Wales, Sydney, Australia. The BrienHolden Vision Institute and Vision CooperativeResearch Centre have received research fundsfrom B+L, AMO, and Allergan and have propri-etary interest in products from Alcon, Cooper-Vision, and Carl Zeiss. You can reach him [email protected].

From a clinical standpoint, the amount of redness produced by a contact lens is inversely related to the oxygen transmissibility at its periphery.


B Y T H O M A S G . Q U I N N , O D , M S

Prescribing for Presbyopia

Dr. Quinn is in group practice in Athens, Ohio.He is an advisor to the GP Lens Institute and an area manager for Vision Source. He is anadvisor or consultant to Alcon and B+L, has received research funding from Alcon, AMO,Allergan, and B+L, and has received lecture orauthorship honoraria from Alcon, B+L, Cooper-Vision, GPLI, SynergEyes, and STAPLE program.You can reach him at [email protected].

able wear: presbyopes. Thoughwell suited for occasional weardue to specific lifestyle requests(e.g. “I just want contact lensesfor social occasions and when Iwork out”), presbyopes are greatdaily disposable lens candidatesfor other reasons.

Physiological RationaleIt has been well established that

contact lens-related dryness is often a partner on the path to presbyopia (Moss et al, 2008).Meibomian gland dysfunction(MGD), which becomes moreprevalent as we age (Hom et al,1990), has been found to be associ-ated with contact lens-related dry-ness (Young et al, 2012). MGDreduces the lipids available to thetear film, promoting more rapidtear break-up, and resulting in arelatively drier lens surface that accumulates deposits more quickly.This surface spoilage leads to reduced contact lens comfort,episodes of “foggy” vision, and ultimately contact lens dropout.

In ControlPresbyopes may lack ocular

vigor, but many have financial independence. When presentedwith the indisputable case of how

daily disposable lenses can im-prove their quality of life, manypresbyopes decide on the spot togo with your recommendation.

Money TalksWhen discussing the cost of

contact lenses, we break out material fees from our service fee.Material fees are set to be com-petitive with online contact lenssources. When presenting mate-rial costs, be sure to factor inmanufacturer rebates, which canbe as much as $85 to $100.

Also remind patients that, withdaily disposable lenses, there’s noneed to buy contact lens care solutions. This cost savings helpsoffset the expense of materials.

A Little PhilosophyWe believe daily disposable

lenses are a great option for virtu-ally all contact lens wearers, so werecommend daily disposable lenses to most patients. We assessa lower service fee to fit daily dis-posable lenses as opposed to whatwe charge for 2-week or monthlyreplacement lenses. We feel goodabout this approach because:

1. It encourages patients tochoose the daily disposable option

2. Patient response to daily

Ddaily disposable lenses may be ideal for adoles-cents and occasional contact lens wearers (Wag-ner et al, 2011; Efron et al, 2012), but there’sanother population that’s ideal for daily dispos-

disposable lenses is almost univer-sally positive. As such, we gener-ally spend less time managingthese patients.

3. When all is said and done,we’re still making more profit by prescribing daily disposablelenses than we’d earn fitting 2-week or monthly lenses.

Make a RecommendationThe final key to success with

daily disposable lenses is to makea firm recommendation for thismodality. If you believe, as I do,that daily disposables are the wayto go for most patients, state thatwith confidence. Most patientsappreciate clear guidance.

Everybody’s HappyDaily disposable lenses provide

patients with a healthy option insoft lens wear. When pursued,your office benefits from happypatients and higher profit mar-gins.

When presented in the rightway, everybody wins with dailydisposables! CLS


Daily Disposables: ProblemSolver for the Presbyope


B Y N E I L P E N C E , O D , F A A O

Contact Lens Design & Materials

Dr. Pence is the associate dean for Clinical andPatient Care Services, Indiana University Schoolof Optometry in Bloomington, Indiana. He hasreceived travel expenses, stipend, or reim-bursement from Alcon and Bausch + Lomb.You can reach him at [email protected].

markets during the past year, isthe first water gradient soft con-tact lens. What’s unique aboutthis lens is that the water contentis not constant throughout thelens, but rather it changes fromthe main body or core of the lensto the surface. Here’s a briefoverview of the key characteris-tics of this material and the watergradient phenomenon.

Novel Water Content PropertiesDailies Total1 lenses are man-

ufactured from a new material,delefilcon A, using a modificationof Alcon’s Lightstream Technol-

ogy, the manufacturing processused to produce the Dailies AquaComfort Plus daily disposablecontact lens. At the core of theDailies Total1 contact lens,which comprises just over 90 percent of the lens, is a siliconehydrogel material with a watercontent of 33 percent. The sur-face of the lens is designed with awater content of over 80 percent.The change in water content and lens structure occurs fairlyrapidly in the outer 5 percent ofthe lens on both sides or surfaces. Oxygen transmissibility, lens

modulus or stiffness and the resul-

The introduction of a new daily disposable contactlens may signal the need for a new category of lens material. The Dailies Total1 contact lens(Alcon), which was launched in various European

tant effect on handling, and lens fit-ting characteristics are propertiesdetermined by the core of a contactlens. With its 33 percent water con-tent core, the Dailies Total1 lenshas the highest oxygen transmissi-bility of any daily disposable lens onthe market. It has a Dk of 140 and aDk/t of 156 for a –3.00D lens witha center thickness of 0.09 mm.Wettability, lubricity or low

coefficient of friction, the abilityto resist deposits or soiling andoverall biocompatibility with theocular surfaces are key character-istics of a contact lens surface. Awater content of over 80 percentat the surface should result in awettable, lubricious lens.

Winning CombinationWith U.S. Food and Drug

Administration clearance alreadysecured, 2013 will see the introduc-tion of Dailies Total1 lenses in theUnited States. The advent of thisnovel new contact lens materialwith gradient water content prop-erties and the benefits it may bringwill be eagerly awaited. The highoxygen transmission of a siliconehydrogel lens with the surface ad-vantages of a high water content atthe surface should be a winningcombination for an ever-growingnumber of patients wearing dailydisposable contact lenses. CLS

Novel Water Gradient Lens Material

Figure 1. Schematic representation of Dailies Total1 water gradient contact lenses

>80 33 >80


B Y W I L L I A M T O W N S E N D , O D , F A A O

Dry Eye Dx and Tx

Dr. Townsend practices in Canyon, Texas, andis an adjunct professor at the University ofHouston College of Optometry. He is presidentof the Ocular Surface Society of Optometry andconducts research in ocular surface disease,lens care solutions, and medications. He is alsoan advisor to Alcon, B+L, CooperVision, Tear-lab Corporation, and Vistakon. Contact him [email protected].

What Studies Tell UsIn a multisite clinical study, researchers investigated potentialcauses for contact lens discontin-uation (Young et al, 2002). Theyfound the majority of patientswho discontinued lens wear (51 percent) did so because ofdiscomfort, and the most com-monly reported type of discom-fort was dryness (40 percent).More recently, researchers

surveyed 4,207 contact lens wearers to determine why theystopped wearing their lenses(Dumbleton et al, 2013). Fortypercent of the patients surveyedhad discontinued lens wear for at least 4 months. The most commonly reported reasons for discontinuation were discom-fort (24 percent) and dryness (20 percent).

Dryness and DiscomfortPatients experiencing contactlens dryness may report varioussymptoms, such as discomfort, irritation, burning, stinging, foreign body sensation and visualblurring (Sindt 2007), which maybe caused by poor prelens tearstability, lens material or lens deposits. Contaminants begin to

adhere to a lens surface withinminutes of application (Brennanand Coles 2000), and the degreeand type of deposits are influ-enced by the water content, ionicproperties and silicone contentof a lens. Because lens depositsdecrease prelens tear filmbreakup time, they may exacer-bate the sensation of dryness(Sindt 2007).Lipids can significantly affect

contact lens wear, and our appre-ciation of their function and im-pact on the ocular surface andcontact lenses has expanded overthe last decade (Panaser andTighe 2012; Pucker and Nichols,2012). For example, we havelearned a lipid coating increasesover time, and the aqueous tearscannot form a stable layer over alipid-coated contact lens (Bren-nan and Coles, 2000). Multipurpose contact lens

solutions are designed to remove deposits, but they are never 100 percent successful in doingso (Brennan and Coles, 2000). In addition, improper lens caremay leave some deposits on thelenses, leading to poor comfortand vision. Wu et al (2010)found that many patients wear-

Despite advances in soft contact lens materials,design and surface characteristics and improve-ments in care solutions, discomfort and drynesslead many patients to stop wearing their lenses.

ing daily wear lenses exhibitedpoor hand hygiene and inade-quate lens and storage casecleaning and had difficulty remembering when to return foraftercare.

Banish Deposits DailyHow can we help patients continue to wear their lensescomfortably when they have dryness or comfort issues? Oneoption is to prescribe daily replacement lenses. Daily disposable lenses may

reduce the risk of noncomplianceand complications associatedwith surface deposits, thus improving comfort and the totallens-wearing experience for patients.Fahmy and colleagues (2010)

refitted symptomatic patientswho replaced their lenses at intervals of 1 to 4 weeks intoDailies AquaComfort Plus lenses.At the end of 4 weeks, they foundstatistically significant improve-ments in symptoms as well as inlimbal and bulbar redness andconjunctival staining. CLS


How Daily Disposable Lenses Can Address Contact Lens Dryness


B Y S U S A N J . G R O M A C K I , O D , M S , F A A O

Contact Lens Care & Compliance

Dr. Gromacki is a diplomate in the AmericanAcademy of Optometry's Section on Cornea,Contact Lenses and Refractive Technologiesand practices in Chevy Chase, Md.

greater overseas, where they rep-resent roughly 35 percent of con-tact lens sales in Europe and 55percent in Asia (Nichols, 2012). These statistics shouldn’t be

surprising, since daily disposablesoffer convenience, particularly forpart-time wearers and people whotravel and they provide new-lenscomfort every day. In comparisonwith frequent replacement (2 weeks or more) daily disposablelens wear has been shown to mini-mize lens deposition and tarsal ab-normalities and provide bettersubjective vision and overall satis-faction (Solomon et al 1996).What’s more, daily disposable

lens wear eliminates the need forcare solutions and with them, thepossibility of preservative uptakeand release from lens care prod-ucts. It also eliminates the needfor a lens storage case, a potentialsource for contamination. Perhapsthe most important benefit of dai-ly disposable contact lenses is theelimination of concern regardingcompliance with lens care re-quired with re-usable lenses.

Replacement Compliance Many practitioners have diffi-

culty monitoring how closely theirpatients follow their lens wear and

replacement instructions. Whenquestioned, many patients, espe-cially part-time lens wearers, havedifficulty remembering how fre-quently they replace their lenses.A peer-reviewed paper by

Dumbleton et al (2010) presentssubstantive data on compliancerates with soft contact lens replacement frequency. The researchers analyzed responsesfrom 2,232 patients wearing sili-cone hydrogel and daily dispos-able lenses in North America.They found that those who weardaily disposable contact lenses reported the highest rates of compliance. In the United States,patients wearing daily disposablessaid they “always” replace theirlenses as recommended by themanufacturer 82 percent of thetime, as compared with 34 percentfor 1-month lenses and 25 percentfor 2-week lenses. When factoringout patients whose practitionersinstructed them to replace thelenses less frequently than themanufacturer recommends, thecompliance rates for lens replace-ment were 88 percent for dailydisposables, 73 percent formonthly lenses and 48 percent forbiweekly lenses. What do thesenumbers mean for our patients?

Daily disposable contact lenses represent a grow-ing segment of the soft lens market in the United States, where they now comprise 17 percent of all fits and refits. Their usage is even

Good compliance means cleanerlenses, which ultimately shouldhelp reduce the incidence of manycontact lens-related complica-tions. On the other hand, there is more to compliance than justreplacement. For daily disposablelenses, overnight wear and re-usewithout disinfection are perhapsof the greatest concern.

Complications MinimizedChalmers and colleagues

(2010) reviewed the records of1,276 soft lens wearers, represent-ing 4,120 office visits and foundno significant correlation betweendaily disposable lenses and inflam-matory or infectious events. Morerecently, in a carefully controlledevaluation of 166 symptomaticsoft contact lens related cornealinfiltrative events, use of daily disposable lenses was found to beprotective (over 12x) in compari-son to reusable lenses (Chalmers2012).Although compliance alone will

never completely safeguard patients from the potential ofcomplications, it is clearly a stepin the right direction. Daily dis-posable lens wear provides thepractitioner and patient with themost compliant-friendly way towear contact lenses. CLS


Compliance With Daily Disposable Contact Lenses


The Shifting Prescribing Paradigm

Daily disposable contactlenses have come along way since their in-troduction in the1990s, owing to ad-

vances in material composition andmanufacturing processes. These lens-es are recognized by patients and eye-care professionals not onlyfor their convenience butalso because they’re ahealthy option. The risingappreciation of this modali-ty is evidenced by increas-ing prescribing frequencyworldwide, even in theUnited States, where prac-titioners have been slow toembrace this modality. Inthis article, I discuss the reasons whydaily disposable contact lenses arechallenging other modalities for thetop prescribing spot in many prac-tices.

New-lens Comfort Every DayDespite many years of research and im-plementation of various clinical man-agement approaches and algorithms,dryness and discomfort with contactlens wear persist. In one study, 79 per-cent of lens wearers reported ocular dis-

comfort, and 77 percent reported vary-ing degrees of dryness.1 Non-lens wear-ers also reported significant increases inlate-day ocular discomfort, visualchanges, soreness and irritation.1What’s more, symptoms of ocular dis-comfort and dryness are the primaryreasons why patients become dissatis-

fied and stop wearing their lenses.2Overall comfort and end-of-day com-fort remain elusive goals.

Daily disposable contact lensesprovide a fresh, clean surface eachday, and a clean lens surface can beexpected to enhance comfort. Whencompared with conventional and fre-quent replacement lenses (e.g., 2-week, monthly), daily disposablesdisplayed less surface deposition andbetter overall lens-wearing satisfac-tion.3

Dr. Nichols is the Kevin Mc-Daid Vision Source Professor at the University of Houston College of Optometry as well as the editor-in-chief of ContactLens Spectrum and editor ofthe weekly e-mail newsletterContact Lenses Today. Hehas received research funding or lecture honorariafrom Alcon Laboratories Inc.,Bausch + Lomb and Vistakon.

Learn why so many practitioners now choose daily disposables as their go-to lenses.

D A I L Y D I S P O S A B L E S

B y J a s o n J . N i c h o l s , O D , M P H , P h D

Daily disposable contactlenses provide a fresh, clean

surface each day, and a cleanlens surface can be expected

to enhance comfort.


Cost Effective for Part-time WearThe cost of daily disposable contact lenses has beenconsidered a primary barrier to prescribing thismodality. In fact, a 2011 Quick Poll4 by ContactLenses Today showed that cost is the number onereason (58 percent) why eyecare practitioners don’tprescribe daily disposables [Oct. 23, 2011]. A recentstudy found that daily disposables can, indeed, becost-effective for part-time wearers.

Efron and colleagues examined the cost-per-wearof daily, 2-week and monthly replacement lenses.5They estimated the annual cost of professional fees,care solutions and lenses and divided that sum by thenumber of times the lenses are worn per year. Theyassumed patients were fully compliant with theirwearing schedules and lens care and that they wouldmake the most cost-effective purchases of lenses andcare solutions. The study showed that the cost-per-wear of daily disposable spherical lenses is lowerthan for reusable spherical lenses when worn from 1 to 4 days per week. At 5 days of lens wear perweek, the cost-per-wear is virtually the same for allthree spherical lens replacement frequencies, and at6 or 7 days of lens wear per week, the cost-per-wearof daily disposables is higher.

Although some lens wearers and practitioners mayperceive daily disposable lenses as more costly, thisstudy found that part-time wearers may receive theadditional benefit of a less expensive modality withimproved convenience. A 2012 Quick Poll4 by Con-tact Lenses Today showed that 76 percent of respon-dents believe daily disposable contact lenses are moreconvenient than 2-week and monthly replacementlenses [Nov. 11, 2012].

Improved Compliance, Fewer ComplicationsEye health is of utmost importance to all of us,which is yet another reason to consider prescribingdaily disposable lenses. In a 2010 Quick Poll4 byContact Lenses Today, 89 percent of respondentsbelieved the daily disposable modality is associatedwith a general reduction in contact lens-associatedcomplications [Dec. 19, 2010]. Thus, the daily dis-posable modality may play an important role in pro-moting ocular health with contact lens wear, andthere may be several reasons for this.

In a recent Web-based survey, contact lens wearersreported low compliance in hand-washing, lens-wear-ing times, rubbing and rinsing lenses, topping off solu-tions and lens case cleaning.7 None of the respondentswearing planned replacement or daily wear soft lensesor GP lenses reported total compliance; however, 8.9 percent of U.S. daily disposable lens wearers re-

ported full compliance in all behaviors.In another study, researchers found that practi-

tioners were more compliant in prescribing the man-ufacturer’s recommended replacement schedule fordaily disposable lenses than for 2-week replacementlenses.8 Similarly, patients were more likely to adhereto the recommended replacement schedule for dailydisposable lenses than for 2-week replacement lens-es. In other studies that compared patients wearingdaily disposables with those wearing conventionaldaily lenses or frequent replacement lenses, those inthe daily disposable groups had lower complicationrates.3,9

Although one study10 found an increased risk of


OAddresssing Allergy Symptoms

cular allergy symptoms can be especiallychallenging for contact lens wearers, becauseallergens and irritants can accumulate on lenssurfaces. Replacing lenses daily can help improve comfort for allergy prone patients.3

A study by Solomon and colleagues foundthat patients wearing daily disposable lenseshad decreased lens deposits and fewer associ-ated tarsal abnormalities than those wearing 2-week replacement lenses.3 Another studycompared comfort and slit-lamp findings forcontact lens patients with ocular allergy symp-toms. In this crossover study, patients woredaily disposable lenses for 1 month and newpairs of their habitual lenses (mostly 2-weekand monthly replacement modalities) for 1 month during allergy season.6 When compar-ing comfort, 67 percent of the patients report-ed better comfort with the daily disposablelenses than with their habitual lenses; 18 per-cent reported improved comfort with a newpair of their habitual lenses. Slit-lamp findingsof bulbar redness, corneal staining, palpebralredness and lid roughness were improved withthe daily disposable lenses compared with newhabitual lenses.6 Some study participants re-ported they were able to reduce or discontinueuse of their allergy medications while wearingdaily disposable lenses.6


microbial keratitis with some daily disposable lenses— a somewhat perplexing finding — a more recentstudy found daily disposable wear to be highly pro-tective against symptomatic corneal infiltrativeevents.11 Although daily disposable lens wear still re-quires proper hand-washing and compliance withdaily replacement, this modality has eliminated theneed for cleaning, disinfecting and storing lenses.Perhaps the removal of these steps has helped to im-prove compliance.

A Good Fit for KidsChildren can be successful contact lens wearers,12-14and they report significantly higher satisfaction withtheir quality of vision when wearing contact lenses asopposed to eyeglasses during sports participation.15Similarly, children who wear contact lenses reportsignificantly higher self-perception of their physicalappearance and social acceptance than those of thesame age who wear eyeglasses.16

Studies specifically examining daily disposablelenses and children found high success rates.12-14 Thechildren in these studies demonstrated good vision,good ocular health with no significant complications,and excellent lens-handling skills. Most of the chil-dren and their parents reported high levels of satis-faction with contact lens wear. The majority ofwearers preferred contact lenses over spectacles forvision, comfort and their appearance.12 In addition,having a back-up supply of daily disposable lenses ishelpful for children, who may lose or damage theirlenses more often than adults.14

Because daily disposable lenses don’t requirecleaning and disinfecting, they may be of particularbenefit to children.14 While careful hand-washingand diligent attention to prescribed wearing timesand follow-up visits remain important responsibili-ties for children and parents, daily disposable lensesmay provide a convenient and consistently clean op-tion.

Prescribing Rates on the RiseAccording to an international survey, daily dispos-able lenses, while not as widely prescribed as 1- and4-week replacement lenses, have gained popularity inthe countries surveyed (Australia, Canada, Japan,The Netherlands, Norway, the United Kingdom,and the United States).17 Although they are especiallypopular in Japan, Norway and the United Kingdom,this survey found a significant increase in the pre-scribing rate for daily disposable lenses in the lesserprescribing countries (Australia, Canada, The

Netherlands and the United States), especially in thelast 3 years of the survey (2006 to 2008). Also of notein this survey, daily disposable lenses were wornmore often by men, part-time wearers and patientswho were slightly younger than those wearingreusable soft lenses.

Newly released data from 40 countries during theperiod 2007 to 2011 show daily disposable lenses aregaining in popularity and now represent nearly 25 percent of the soft lenses prescribed in thesecountries.18 According to this study, daily disposablesare most frequently prescribed in Japan and parts of

Northern Europe. According to these researchers,cost appears to be the most significant factor in pre-scribing daily disposable lenses, and they found a re-lationship between a country’s gross domesticproduct (basically, a measure of average wealth of in-dividuals in a nation) and frequency of daily dispos-able fittings. In general, the countries with a higherincome were associated with more daily disposablefittings. One notable exception was the U.S. market.Although the United States was among the top fivecountries for gross domestic product, it ranked 29thout of 40 countries for proportion of daily disposablefittings.18 Despite this puzzling finding, optimism forthe growth of daily disposable lenses remains high inNorth America.

More recent data for the United States indicatethat for the past few years, daily disposable lenseshave enjoyed the highest yearly percentage growthrates of almost all categories.19 Data from the ContactLens Spectrum Annual Report 2012 show that whencompared with other modalities, such as 2-week re-placement or quarterly replacement lenses, the dailydisposable category showed substantial gains in 2012


Recent data for the United States indicate

that for the past few years,daily disposable lenses

have enjoyed the highestyearly percentage growth

rates of almost all categories.


compared to 2011. Daily disposables were used inabout 17 percent of fits and refits for 2012, up from14 percent in 2011 and 11 percent in 2009. Datafrom GfK Retail and Technology showed the dailydisposable category grew by nearly 19 percent in the

United States between January and September 2012when compared with the same time period in 2011.19

Trend information for daily disposables for 2013also appears positive. Data from a Contact Lens Spec-

trum survey regarding anticipated use for the comingyear reveals that 64 percent of respondents expect toprescribe silicone hydrogel daily disposables, and 52percent expect to prescribe hydrogel daily disposablelenses more frequently in 2013.19

When comparing data from 2011 and 2012 forEurope, Japan and the United States, daily dispos-ables exhibited the highest growth rates in the U.S.market.19

Finally, a 2012 Quick Poll4 by Contact LensesToday showed that 44 percent of respondents be-lieve daily disposables will dominate the contact lensmarket in the next few years [Oct. 28, 2012]. Thesetrends suggest that practitioners and patients are re-alizing the benefits of the daily disposable modality.

Understandable TrendDaily disposable contact lenses are available with anextensive array of vision-correcting capabilities innumerous lens materials and a wide range of parame-ters. The prescribing rates for daily disposables aretrending upward, and the benefits of daily dispos-ables make that an easy trend to understand. CLS


tact lenses: a case-control study. Ophthalmology2008;115(10):1647-1654.

11. Chalmers RL, Keay L, McNally J, Kern J. Multicenter case-control study of the role of lens materials and care productson the development of corneal infiltrates. Optom Vis Sci2012;89(3):316-325.

12. Li L, Moody K, Tan DT, Yew KC, Ming PY, Long QB.Contact lenses in pediatrics study in Singapore. Eye ContactLens 2009;35:188-195.

13. Walline JJ, Jones LA, Rah MJ et al; CLIP Study Group. Con-tact Lenses in Pediatrics (CLIP) Study: chair time and ocularhealth. Optom Vis Sci 2007;84:896-902.

14. Walline JJ, Long S, Zadnik K. Daily disposable contact lenswear in myopic children. Optom Vis Sci 2004;81:255-259.

15. Rah MJ, Walline JJ, Jones-Jordan LA, et al. Vision specificquality of life of pediatric contact lens wearers. Optom Vis Sci2010;87:560-566.

16. Walline JJ, Jones LA, Sinnott L, et al; ACHIEVE StudyGroup. Randomized trial of the effect of contact lens wear onself-perception in children. Optom Vis Sci 2009;86:222-232.

17. Efron N, Morgan PB, Helland M, et al. Daily disposablecontact lens prescribing around the world. Cont Lens AnteriorEye 2010;33:225-227.

18. Efron N, Morgan PB, Woods CA; The International ContactLens Prescribing Survey Consortium. An international survey of daily disposable contact lens prescribing. Clin ExpOptom 2013;96:58-64.

19. Nichols JJ. Contact Lenses 2012. Contact Lens Spectrum2013;28(1):24-26, 28, 29, 52.

References1. Begley CG, Chalmers RL, Mitchell GL, et al. Characteriza-

tion of ocular surface symptoms from optometric practices inNorth America. Cornea 2001;20: 610-618.

2. Richdale K, Sinnott LT, Skadahl E, Nichols JJ. Frequency ofand factors associated with contact lens dissatisfaction anddiscontinuation. Cornea 2007;26:168-174.

3. Solomon OD, Freeman MI, Boshnick EL, et al. A 3-yearprospective study of the clinical performance of daily dispos-able contact lenses compared with frequent replacement andconventional daily wear contact lenses. CLAO J 1996;22:250-257.

4. Contact Lenses Today. http://www.cltoday.com/archive.asp5. Efron N, Efron SE, Morgan PB, Morgan SL. A ‘cost-per-

wear’ model based on contact lens replacement frequency.Clin Exp Optom 2010;93:253-260.

6. Hayes VY, Schnider CM, Veys J. An evaluation of 1-day dis-posable contact lens wear in a population of allergy sufferers.Cont Lens Anterior Eye 2003;26:85-93.

7. Morgan PG, Efron N, Toshida H, Nichols JJ. An internationalanalysis of contact lens compliance. Cont Lens Anterior Eye2011;34:223-228.

8. Dumbleton K, Richter D, Woods C, Jones L, Fonn D. Com-pliance with contact lens replacement in Canada and theUnited States. Optom Vis Sci 2010;87:131-139.

9. Suchecki JK, Ehlers WH, Donshik PC. A comparison of con-tact lens-related complications in various daily wear modali-ties. CLAO J 2000;26:204-213.

10. Dart JK, Radford CF, Minassian D, Verma S, Stapleton F.Risk factors for microbial keratitis with contemporary con-

The prescribing rates fordaily disposables are trending upward, and the benefits of daily disposables make that aneasy trend to understand.


© 2013 Novartis 12/12 AOM13003JAD

If your presbyopic patients aren’t experiencing clear binocular vision, they may not be in AIR OPTIX® AQUA Multifocal contact lenses.

* Dk/t = 138 @ -3.00D. **Among those with a preference. †As compared to PureVision^ Multi-Focal and ACUVUE^ OASYS^ for PRESBYOPIA contact lenses. ^Trademarks are the property of their respective owners.

Important information for AIR OPTIX® AQUA Multifocal (lotra� lcon B) contact lenses: For daily wear or extended wear up to 6 nights for near/far-sightedness and/or presbyopia. Risk of serious eye problems (i.e. corneal ulcer) is greater for extended wear. In rare cases, loss of vision may result. Side effects like discomfort, mild burning or stinging may occur.

References: 1. In a randomized, subject-masked clinical study at 20 sites with 252 patients; signifi cance demonstrated at the 0.05 level; Alcon data on fi le, 2009. 2. Rappon J. Center-near multifocal innovation: optical and material enhancements lead to more satisfi ed presbyopic patients. Optom Vis Sci. 2009;86:E-abstract 095557. 3. In a randomized, subject-masked clinical trial at 6 sites with 47 patients; signifi cance demonstrated at the 0.05 level; Alcon data on fi le, 2008. 4. Based on a third-party industry report, 12 months ending October 2012; Alcon data on fi le.

See product instructions for complete wear, care and safety information.

AIR OPTIX® AQUA Multifocal contact lenses: Are preferred by patients over other multifocal contact lenses1,2,3**†

Allow for a smooth transition from center-near to intermediate and distance zones Deliver improved binocular vision, predictable clinical results, and decreased fi tting time due to a consistent ADD effect

#1 multifocal

lens4

Make a smooth transition with a great multifocal lensLearn more at myalcon.com

AIR OPTIX® AQUA Multifocal Contact Lenses

Contact Lens Spectrum 2/1/13

80980 AOM13003JAD CLS.indd 1 1/14/13 3:34 PM

Despite years of researchand discovery, contactlens-related discomfort(CLD) remains highlyprevalent, with an esti-

mated 50 percent of U.S. lens wearersaffected.1 Wearers frequently reportgeneral symptoms of dryness and dis-comfort, as well as specific com-plaints, such as grittiness anditchiness.2

A study involving patients in theUnited States and Canada found that79 percent of contact lens wearers re-ported discomfort, and 77 percent re-ported dryness.3 Together thesesymptoms represent the number onereason why patients stop wearingtheir contact lenses, which is particu-larly significant when we considerthat about 3.5 million people startwearing contact lenses each year, butapproximately 2 to 3 million estab-lished lens wearers discontinue lenswear each year.4

Recognizing symptoms is relativelystraightforward for clinicians, butidentifying signs can be challenging.In a recent study, 23 percent of softlens wearers with self-reported dry-ness showed no signs upon clinical ex-amination using various standardtests.5 Furthermore, no single sign —significant corneal staining or reducedtear meniscus height, for example —

was present in the majority of lenswearers.

This study supports the findings ofprevious studies: Symptoms, evenwhen significant, frequently do notcorrelate with ocular signs. Youngand colleagues5 also reported thatsome contact lens-related findings ap-pear to be common among these pa-tients, such as poor lens wetting, rapidtear breakup times and higher levelsof deposits on lenses. They also foundthat asymptomatic individuals consis-tently report longer average comfort-able lens-wearing times and lessend-of-day discomfort. In contrast,patients with dryness symptoms re-ported, on average, 3.9 to 4.3+ hoursof uncomfortable lens wear per day.

Epidemiology of CLDResearchers have determined that

more women than men have CLD,6but the reasons for the higher preva-lence among women are not fully un-derstood. Some have hypothesizedthat hormones may play a role or thatwomen are more likely to reportsymptoms.7

Studies reveal interesting informa-tion about age and contact lens wear.Richdale and colleagues,2 who corre-lated contact lens dropout with ocu-lar discomfort and dryness, found intheir study that older patients (by ap-

C O N T A C T L E N S C O M F O R T

Dealing With Discomfort

By Carol ine A. Blackie, OD, PhD, FAAO, Donald R. Korb, OD,F AAO , & K e l l y N i c h o l s , O D , M PH , P h D , F AAO , D i p l P H

An in-depth look at the epidemiology, diagnosis andtreatment of contact lens-related dryness.

Dr. Blackie is a charter member of the Ocular Sur-face Society of Optometry.She is the clinical research scientist for TearScience Inc. as well as for Korb & Associates in Boston.

Dr. Nichols is a professor at the University of HoustonCollege of Optometry. Shehas stock options in TearLaband is a consultant/advisor to Alcon, Allergan, Bausch + Lomb and SarCode.She has received researchsupport from Alcon Allergan,SarCode, TearLab and Vistakon.


Dr. Korb is cofounder andchief technical officer atTearScience and cofounderand director of research ofKorb & Associates. He has a proprietary interest in Alcon.

proximately 9.5 years) and those who had startedcontact lens wear at a later age (approximately 4 to 5years later) were more likely to stop wearing contactlenses.

As we would expect, contact lens wearers both-ered by symptoms will decrease wearing time andeventually discontinue lens wear.5 In a cross-sectionalsurvey of 730 people, the permanent discontinuationrate was 24 percent,2 and a more recent survey ofmore than 4,000 Canadian patients found that about23% of those surveyed had discontinued contact lenswear permanently.8

In our experience, some patients who havestopped wearing contact lenses, as well as some cur-rent lens wearers who have significant discomfort orvisual symptoms, feel their quality of life has de-creased, because many appreciate the improved vi-sion and self-perception of physical appearance whilewearing contact lenses.

Mechanisms Underlying Contact Lens Discomfort

Over the past 10 years, numerous mechanismshave been identified as key contributors to dryness incontact lens wearers.•Altered Tear Film: Wearing a contact lens can

produce a spectrum of ocular changes, including in-creased reflex tear secretion, deprivation of the wip-ing action of the lids over the covered ocularsurfaces, elevated tear osmolarity and increased mu-cus production by non-goblet cells in the tarsal con-junctiva.9 As first reported by Tomlinson,10 however,the most important factor influencing discomfortwith contemporary contact lenses is increased evapo-ration from the lens and ocular surfaces.9,10 The im-portance of prelens humidity was clinicallydemonstrated when 30 minutes of 100 percent hu-midity improved the prelens lipid layer thickness andcomfort of hydrogel lenses.9•Lens Wettability: A key factor in the biocom-

patibility of a contact lens is the tear film’s ability toadequately cover and maintain its integrity over thelens surface. Unfortunately, the surface of a contactlens lacks the mucus-attaching properties of thecornea and the ocular surfaces and is not wellequipped to secure the foundational mucus layer(s)essential for forming all layers of the tear film. Thus,the tear film over the contact lens cannot duplicatethe characteristics of the tear film over the cornea.

With contact lens wear, the lipid layer is rarelyequivalent to the usual lipid layer of the tear film inthickness or other characteristics.11 Therefore, therate of evaporation increases, tear film constituents

denature on the lens surface and, in combinationwith the thinner pre- and postlens tear films, frictionbetween the cornea and the contact lens, and the lidwiper and the contact lens is inevitable with resultingdiscomfort.12•Corneal Desiccation: Because contact lens wear

increases evaporation of the tear film, water is drawnfrom the tear film, thinning the postlens tear film.Consequently, the cornea may desiccate beneath athin, high water content lens, leading to corneal ep-ithelial defects and generalized discomfort.13•Lid Wiper Epitheliopathy (LWE): When asso-

ciated with contact lens wear, LWE in otherwisesuitable contact lens wearers is most likely a result ofthe altered characteristics of the tear film betweenthe lens and the lid wiper, compromising lubrication.An inadequate lipid layer is believed to play a signifi-cant role. Without adequate lubrication, the anteriorsurface of the contact lens is presented to the lidwiper at a rate on average of 12 to 15 blinks perminute,14 thousands of times a day. This activity cancause physical trauma, mechanical abrasion and in-flammation of the epithelial cells of the lid wiper, re-sulting in symptoms of discomfort.12 Without anadequate lubricating layer, the lid wiper becomes aprimary source of discomfort with contact lenses.•Giant Papillary Conjunctivitis (GPC): With

the increased use of disposable contact lenses, partic-ularly daily disposables, GPC is less of an issue to-day, but it still may occur. Generally, it is related tothe difficulty in keeping the lenses wet and clean.With compromised wettability or a buildup of de-posits, the friction/trauma applied by the lens to thepalpebral conjunctiva escalates, as does the likelihoodof GPC.•Blinking: Blinking is critical for wetting the oc-

ular and contact lens surfaces, maintaining the lipidlayer and minimizing evaporation, yet it is oftenoverlooked in the clinical examination of a patientpresenting with symptoms. Forceful blinking helpsincrease the lipid layer thickness, presumably by aug-menting the expression from the meibomian glands.9Contact lens wear affects the blink rate and ampli-tude, frequently inhibiting proper blinking and fur-ther exacerbating the detrimental effects of thecontact lens on the tear film.9•Meibomian Gland Dysfunction (MGD): The

blink is considered the primary mechanism for ex-pressing oil from the glands, thus chronically re-duced blink rate and amplitude, which are frequentlyobserved with contact lens wear, can result in a reduced meibomian gland function and secretionoutput within hours.15 MGD may lead to significant



symptoms of ocular discomfort with contact lenswear.16-17 Reduced meibomian gland secretion con-tributes to contact lens discomfort, because evapora-tion from the tear film increases. This may initiatethe cascade of LWE, which may further inhibitblinking. Similarly, if MGD develops during contactlens wear, discomfort may develop.

Although the mechanisms involved in ocular dry-ness associated with contact lens wear are numerousand complex, we know that MGD may well be theleading cause of dry eye18 and the most commoncause of contact lens intolerance.19 These facts playan important role in diagnosing and managing CLD.

Diagnostic AidsTo appreciate the numerous tests required to

evaluate the ocular surface, we must understand theeffects of a contact lens on the eye. Even on ahealthy ocular surface and tear film, a contact lensdisrupts normal tear physiology through multiplemechanisms. For example, it will:20

• Increase prelens tear film thinning and breakuptime

• Alter and thin the lipid layer• Increase evaporation.In addition, the edge of a contact lens introduces

physical and rheological challenges, including thoseresulting from meniscus formation. The surface of acontact lens and adherent material may also trauma-tize the ocular and conjunctival surfaces and presentimmunological challenges.9 Thus, a thorough assess-ment of the patient’s symptom history, includingmanagement successes and failures, as well as a com-plete evaluation of the ocular surface, the eyelids, theblink and the interaction of the contact lens with thetear film and ocular environment is important forsuccessful contact lens wear.

The following tests are often used in clinical prac-tice:•Questionnaires: The Contact Lens Dry Eye

Questionnaire,21 the Standard Patient Evaluation ofEye Dryness (SPEED) questionnaire22 or other sur-veys that ask about frequency and intensity of symp-toms and late-day dryness may reveal importantinformation.•Tear Film Breakup Time: Measured before

contact lens application and generally performedwith fluorescein, an average of two or more readingsin seconds should be taken with the biomicroscope.Tear film breakup time can also be measured usingthe Keratograph 5M (Oculus Inc.).

• Corneal Staining (fluorescein): Extent and loca-tion graded from 0 to 4.

• Conjunctival Staining (lissamine green): Extentand location graded from 0 to 4.

• Bulbar, Limbal and Eyelid Margin Hyperemia:Graded from 0 to 4.

• Palpebral Conjunctival Evaluation: – Hyperemia, roughness, papillary response

graded from 0 to 4.– GPC graded from 0 to 4.

• Lid Wiper Epitheliopathy: Graded from 0 to 4.• Meibomian Gland Evaluation:

– Function (e.g., oil availability upon lightpressure).

– Secretion quality graded from 0 to 4.– Appearance (e.g., orifice capping, telangiecta-

sia, etc.).• Meibography: Graded from 0 to 4; can be performed via transillumination or with a meibographer.

• Blink Completeness• Tear Osmolarity: Scores greater than307mOsm/L indicate dry eye.

• Contact Lens Surface Wettability: Graded from0 to 4.

• Schirmer or Phenol Red Thread Test: Record-ed in mm/min. or seconds.

For more insights, see “Clinical Patterns Aid As-sessment.”

What Are We to Do?While some patients experience CLD symptoms

only in certain environments, such as the extremelylow humidity in an airplane, others experience severeand constant symptoms that lead to termination ofcontact lens wear. Thus, while we can choose fromnumerous management strategies, we must be mind-ful that each patient is unique, and a tailored medicalmanagement approach, including ocular surface andlid assessment or if indicated, temporary or perma-nent cessation of lens wear, may be necessary. Treat-ment options include the following:•Adjust Ambient and External Environment:

Increased periocular humidity can have a dramaticand positive effect on the prelens tear film and con-tact lens comfort. Experiments with goggles to con-trol evaporation have demonstrated decreasedevaporation of the tear film thinning rates23 and re-duced corneal epithelial erosions.24

These results continue to affirm what we know isthe key to increasing ocular comfort during contactlens wear: a robust tear film with an adequate lipidlayer and a healthy blink mechanism. A tear film thatis adequate or marginally adequate without a contactlens may not be adequate in the presence of a contact



lens. Work environment, room humidity,outdoor humidity/aridness and dryingenvironments (heating/air conditioning)all play a role and can be discussed withpatients. Indoor humidifiers and appro-priate placement of computer monitorsin the workplace can have a noticeableimpact on a contact lens patient’s com-fort and may be important in the overallmanagement plan.•Recommend Rewetting Drops:

Rewetting drops may help relieve symp-toms of dryness and improve for someindividuals however, patients may viewthem as inconvenient if they must usethem frequently. Numerous brands ofcontact lens rewetting drops are availableto consumers. We believe eyecare profes-sionals should recommend a specificproduct, including instructions for use. •Change Lens Replacement Interval:

Patients with CLD may benefit from re-placing their lenses more frequently.When compared with frequent replace-ment (1 to 3 months) and 2-week re-placement lenses, daily disposable hydrogel lensesshowed fewer lens surface deposits, and wearers re-ported better comfort and overall satisfaction.25 Dailydisposable hydrogel lenses may also help alleviateend-of-day dryness symptoms.26•Change Lens Material: Certain polymers and

surface treatments provide better wettability and amore normal prelens tear film than others. Refittingsoft lens wearers who have CLD symptoms into sili-cone hydrogel materials may improve comfort. Astudy found that patients who had CLD symptomsand were wearing soft lenses experienced significant-ly improved dryness and comfort, and they increasedtheir comfortable wearing time after they were refitwith a silicone hydrogel material.6 In addition, wehave found that patients may be more comfortablewith a lower modulus silicone hydrogel lens, or evena conventional hydrogel lens, if they find a highermodulus silicone hydrogel lens uncomfortable. Addi-tional recent studies have concluded that mechanicalproperties, such as the coefficient of friction of alens, surface lubricity and lens stiffness are propertiesdriving lens comfort.27,28 For instance, we know that acontact lens wearer will blink thousands of times aday, leading to a repeated mechanical interaction be-tween the eyelid and contact lens surface and edge.There has been at least one study that has showedthat a contact lens wearer has a reduction in the

number of functional meibomian glands than non-lens wearers.29 One implication that the authorsmake is that the mechanical interaction between thelids and contact lens surface may lead to an atrophyof some of the meibomian glands. Thus, it seemsreasonable to look at material characteristics such ascoefficient of friction to help reduce the mechanicalinteraction and frictional drag between the lens andthe lid as much as possible. •Change Care Regimen: When contact lens

wearers complain of discomfort, practitioners oftenchange contact lens disinfecting solutions. Re-searchers have found a particular brand of multipur-pose solutions (MPS) may provide improved overalland end-of-day comfort and overall satisfaction for alens wearer when compared to other MPS brands.4,30Changing a patient’s care regimen from an MPS sys-tem to a hydrogen peroxide-based system may resultin longer comfortable lens wear times.31 As withmany aspects of clinical practice, each lens wearer re-sponds differently to each solution. Therefore, an in-dividualized approach may be necessary to find themost appropriate lens care solution.•Discuss Essential Fatty Acid Supplementation:

Patients with CLD have reported improved symptomsof dryness and increased overall comfort, and they havedemonstrated improved tear meniscus height while us-ing omega-3 and omega-6 dietary supplements.32


TClinical Patterns Aid Assessment

he broad range of ocular signs associated with CLD cou-pled with a potential lack of correlation between signs andsymptoms underscore the need for a variety of tests toscreen for CLD.5

An equally important part of the clinical workup is uncov-ering symptoms that may be associated with CLD. By rou-tinely administering surveys or asking specific questionsabout each patient’s lens-wearing experience, you can ob-tain valuable information that reveals the presence andseverity of dryness, for example:

• Reduced overall satisfaction with lens wear• Inability to wear lenses as long as desired• Use of rewetting drops• Recent contact lens refitting to improve comfort or

other symptoms.33

This information can help paint a clinical picture thatpoints toward CLD, even when signs and symptoms fail tocorrelate.


Adding to the CLD ArmamentariumOur understanding of CLD has advanced during

the past several years. We can now direct our effortstoward alleviating these symptoms to multiple areas:new lens polymers, 1-day lenses, lens care productsand methods to prevent evaporation, treatments for



References1. Nichols JJ, Ziegler C, Mitchell GL, Nichols KK. Self-report-

ed dry eye disease across refractive modalities. Invest Oph-thalmol Vis Sci 2005;46:1911-1914.

2. Richdale K, Sinnott LT, Skadahl E, Nichols JJ. Frequency ofand factors associated with contact lens dissatisfaction anddiscontinuation. Cornea 2007;26:168-174.

3. Begley CG, Chalmers RL, Mitchell GL, et al. Characteriza-tion of ocular surface symptoms from optometric practices inNorth America. Cornea 2001;20:610-618.

4. Corbin GS, Bennett L, Espejo L, Carducci S, Sacco A, Han-nigan R, Schatz S. A multicenter investigation of OPTI-FREE RepleniSH multi-purpose disinfecting solutionimpact on soft contact lens patient comfort. Clin Ophthalmol2010;4:47-57.

5. Young G, Chalmers R, Napier L, Kern J, Hunt C, Dumble-ton K. Soft contact lens-related dryness with and withoutclinical signs. Optom Vis Sci 2012;89:1125-1132.

6. Riley C, Young G, Chalmers R. Prevalence of ocular surfacesymptoms, signs, and uncomfortable hours of wear in con-tact lens wearers: the effect of refitting with daily-wear sili-cone hydrogel lenses (senofilcon a). Eye Contact Lens2006;32:281-286.

7. Nichols JJ, Sinnott LT. Tear film, contact lens, and patient-related factors associated with contact lens-related dry eye.Invest Ophthalmol Vis Sci 2006;47:1319-1328.

8. Dumbleton K, Woods CA, Jones LW, Fonn D. The impactof contemporary contact lenses on contact lens discontinua-tion. Eye & Contact Lens 2013;39(1):93-99.

9. Korb DR. Tear film–contact lens interactions. Adv Exp MedBiol 1994;350:403-410.

10. Tomlinson A, Cedarstaff T. Tear Evaporation from the Hu-man Eye - Effect of Contact Lens Wear. J Brit Contact LensAssoc 1982;5:141-150.

11. Young G, Efron N. Characteristics of the pre-lens tear filmsduring hydrogel contact lens wear. Ophthalmic Physiol Opt1991;11:53-58.

12. Korb DR, Greiner JV, Herman JP, et al. Lid-wiper epithe-liopathy and dry-eye symptoms in contact lens wearers.CLAO J 2002;28:211-216.

13. Holden BA, Williams L, Sweeney DF, Swarbrick HA. Theendothelial response to contact lens wear. CLAO J1986;12:150-152.

14. Carney L, Hill R. Variation in blinking with soft lens wear.Int Cont Lens Clin 1984;11(4):250-253.

15. Linton RG, Curnow DH, Riley WJ. The meibomian glands:an investigation into the secretion and some aspects of thephysiology. Br J Ophthalmol 1961;45:718-723.

16. Korb DR, Henriquez AS: Meibomian gland dysfunction andcontact lens intolerance. J Am Optom Assoc 1980;51:243-251.

17. Paugh JR, Knapp LL, Martinson JR, et al. Meibomian thera-py in problematic contact lens wear. Optom Vis Sci1990;67:803-806.

18. Nichols KK, Foulks GN, Bron AJ, et al. The internationalworkshop on meibomian gland dysfunction: executive sum-mary. Invest Ophthalmol Vis Sci 2011;52:1922-1929.

19. Foulks GN. Contact lens-induced dry eye. 2009:http://www.eyecareeducators.com/site/contact_lens_in-duced_dry_eye.htm. Accessed January 22, 2013.

20. Thai LC, Tomlinson A, Doane MG. Effect of contact lensmaterials on tear physiology. Optom Vis Sci 2004;81:194-204.

21. Nichols JJ, Mitchell GL, Nichols KK, Chalmers R, BegleyC. The performance of the contact lens dry eye question-naire as a screening survey for contact lens-related dry eye.Cornea 2002;21:469-475.

22. Korb DR, Herman JP, Greiner JV, et al. Lid wiper epithe-liopathy and dry eye symptoms. Eye Contact Lens2005;31(1)2-8.

23. Kimball SH, King-Smith PE, Nichols JJ. Evidence for themajor contribution of evaporation to tear film thinning be-tween blinks. Invest Ophthalmol Vis Sci 2010;51:6294-6297.

24. Holden BA, Sweeney DF, Seger RG. Epithelial erosionscaused by thin high water content lenses. Clin ExperimentOptom 1986;69:103-107.

25. Solomon OD, Freeman MI, Boshnick, EL, et al. A 3-yearprospective study of the clinical performance of daily dispos-able contact lenses compared with frequent replacement andconventional daily wear contact lenses. CLAO J1996;22:250-257.

26. Peterson RC, Wolffsohn JS, Nick J, Winterton L, Lally J.Clinical performance of daily disposable soft contact lensesusing sustained release technology. Cont Lens Anterior Eye2006;29:127-134.

27. Brennan NA. Contact lens-based correlates of soft lenswearing comfort. Optom Vis Sci 2009;86:E-abstract 90957.

28. Coles C, Brennan NA. Coefficient of friction and soft con-tact lens comfort. Optom Vis Sci 2012;89. E abstract 125603

29. Arita R, Itoh K, Inoue K, Kuchiba A, Yamaguchi T, AmanoS. Contact lens wear is associated with decrease of meibomi-an glands. Ophthalmology 2009;116(3):379-384.

30. Campbell R, Kame G, Leach N, Paul M, White E, Zigler L.Clinical benefits of a new multipurpose disinfecting solutionin silicone hydrogel and soft contact lens users. Eye ContactLens 2012;38:93-101.

31. Keir N, Woods CA, Dumbleton K, Jones L. Clinical perfor-mance of different care systems with silicone hydrogel con-tact lenses. Cont Lens Anterior Eye 2010;33:189-195.

32. Kokke KH, Morris JA, Lawrenson JG. Oral omega-6 essen-tial fatty acid treatment in contact lens associated dry eye.Cont Lens Anterior Eye 2008;31:141-146; quiz 170. 2.

33. Ramamoorthy P, Sinnott LT, Nichols JJ. Treatment, materi-al, care, and patient-related factors in contact lens-relateddry eye. Optom Vis Sci 2008;85:764-772.

LWE, and, most importantly, the treatment of themeibomian glands to improve their secretion by vari-ous methods. With current treatments and new ad-vances still in the pipeline, the future appearspromising for reducing discomfort so that our pa-tients can wear their contact lenses long term. CLS

*AIR OPTIX® NIGHT & DAY® AQUA (lotrafi lcon A) contact lenses: Dk/t = 175 @ -3.00D. Other factors may impact eye health. **Extended wear for up to 30 continuous nights, as prescribed by an eye care practitioner.Important information for AIR OPTIX® NIGHT & DAY® AQUA (lotra� lcon A) contact lenses: Indicated for vision correction for daily wear (worn only while awake) or extended wear (worn while awake and asleep) for up to 30 nights. Relevant Warnings: A corneal ulcer may develop rapidly and cause eye pain, redness or blurry vision as it progresses. If left untreated, a scar, and in rare cases loss of vision, may result. The risk of serious problems is greater for extended wear vs. daily wear and smoking increases this risk. A one-year post-market study found 0.18% (18 out of 10,000) of wearers developed a severe corneal infection, with 0.04% (4 out of 10,000) of wearers experiencing a permanent reduction in vision by two or more rows of letters on an eye chart. Relevant Precautions: Not everyone can wear for 30 nights. Approximately 80% of wearers can wear the lenses for extended wear. About two-thirds of wearers achieve the full 30 nights continuous wear. Side Effects: In clinical trials, approximately 3-5% of wearers experience at least one episode of infi ltrative keratitis, a localized infl ammation of the cornea which may be accompanied by mild to severe pain and may require the use of antibiotic eye drops for up to one week. Other less serious side effects were conjunctivitis, lid irritation or lens discomfort including dryness, mild burning or stinging. Contraindications: Contact lenses should not be worn if you have: eye infection or infl ammation (redness and/or swelling); eye disease, injury or dryness that interferes with contact lens wear; systemic disease that may be affected by or impact lens wear; certain allergic conditions or using certain medications (ex. some eye medications). Additional Information: Lenses should be replaced every month. If removed before then, lenses should be cleaned and disinfected before wearing again. Always follow the eye care professional’s recommended lens wear, care and replacement schedule. Consult package insert for complete information, available without charge by calling (800) 241-5999 or go to myalcon.com.

References: 1. In a survey of 284 daily and extended wear contact lens patients. Alcon data on fi le, 2012. 2. In a survey of 311 optometrists in the U.S.; Alcon data on fi le, 2012.See product instructions for complete wear, care, and safety information.© 2013 Novartis 1/13 AND13001JAD

AIR OPTIX® NIGHT & DAY® AQUAContact LensesLearn more about the lens approved for up to 30 nights of continuous wear at myalcon.com

47% of lens sleepers aren’t telling you how often they sleep in their lenses1

Talk to your patients about AIR OPTIX® NIGHT & DAY® AQUA contact lenses.

**

2

It’s not always this obvious

The Clinical Relevance of Contact Lens Lubricity

Despite advances in con-tact lens materials, de-signs and lens careproducts, discomfort, es-pecially end-of-day dis-

comfort and dryness, continues to bethe predominant reason for discontinu-ation of lens wear.1,2 Although much ef-fort has been put into development ofeffective multifocal soft contact lenses,contact lenses to control myopic pro-gression and attempts to decreasecorneal infection rates, the most effec-tive way to increase the number ofwearers is a corneo-mimetic contactlens surface that provides outstandingend-of-day comfort and therefore sig-nificantly reduce the number ofdropouts from contact lens wear.

Most soft lenses are fully hydratedand comfortable upon insertion. Weknow however that for many lens wear-ers comfort decreases or dryness wors-ens during the day3-5 and the maximalfluid state of the ocular environmentand conventional hydrogel and siliconehydrogel lenses can change6-8 after in-sertion. So the challenge for polymerscientists, mechanical engineers andeveryone else associated with materialand lens development, is how to pre-vent loss of water from the lens surface

and therefore the bulk, or more appro-priately how to effectively make thesurfaces truly biocompatible. Somemanufacturers have claimed to achievesome of these objectives described fur-ther in this article, but before that it isworth describing some of physical andmechanical terms associated with lenssurfaces and their interaction with ocu-lar tissue.

Tribology Tribology, a domain of mechanicalengineering, is the science of friction,lubrication and wear (not as in contactlens wear, but deterioration). It is thestudy of interacting surfaces in rela-tive motion. Subbaraman and Jones9have described how friction and lu-bricity can be measured.

FrictionFriction can be defined as the “resis-tance developed between contactingsurfaces when one of the bodiesmoves, or tends to move, over theother”10 The Coefficient of Friction(COF) is a scaled value which de-scribes the ratio of the force of fric-tion between two surfaces and theforce pressing them together. Thevalue depends in part on the materials.

Dr. Fonn is Founding Directorof the Centre for ContactLens Research and Distin-guished Professor Emeritusat the School of Optometry. He is a graduateof the School of Optometry in Johannesburg, SouthAfrica and the University of New South Wales in Sydney, Australia. He is theimmediate Past President ofthe International Society forContact Lens Research and afounding member of the International Association ofContact Lens Educators inwhich he served as Vice President for 15 years. He is a paid consultant of Alcon and CooperVision.

Using science to provide better comfort for contact lens wearers.

L U B R I C I T Y

B y D e smo n d F o n n , MOp t om , F AAO


Two useful examples are: ice on steel, which wouldhave a low COF, while rubber on asphalt would havea high coefficient of friction. There are several typesof friction / lubrication in the context of contact lenswear. Hydrodynamic lubrication is where a fluid filmcompletely separates two solid surfaces. Boundary lu-brication occurs when the two surfaces come into di-rect contact. Two contrasting contact lens examplesare the lid traversing a soaked hydrogel lens on theeye at high speed (hydrodynamic lubrication) whichwould have a relatively low COF but if the tear film iscompletely dehydrated or the movement speeds arelow the COF would be considerably higher (bound-ary lubrication).

LubricityLubricity can be thought of as the reciprocal of friction.That is when friction is low, lubricity is high. A hydro-gel contact lens surface in its dehydrated state is notparticularly lubricious, however, introducing a fluideven with very low viscosity or soaking the lens in solu-tion will improve the lubricity and reduce friction whenthe eyelid slides across the lens surface. The ability ofthe surface to retain moisture will affect the lubricity.

WettabilityThis is a more commonly used term in the contactlens world and is used to characterize the adherenceof fluid to the lens surface. Wettability can be an in-vitro (or ex-vivo) measure of the contact angle (CA)or a clinical in-vivo assessment of pre-lens tear breakup time (TBUT) measurement. Although these arefrequently quoted values, there are other key factorsthat may correlate better with comfort of contactlenses. Maldonado-Codina and Efron11 suggestedthat the in-vivo interaction of tears and the lens sur-face cannot be predicted by CA measurements. Hys-teresis (difference between the advancing andreceding contact angles) seems to be a better way ofexpressing the laboratory wettability of lenses andTighe has shown that hysteresis values of uncoatedsilicone hydrogels launched in recent years have de-creased significantly, in part due to the markedlygreater water content.12

Clinical Consequences of High Coefficient of FrictionIt is fair to say that the advancements made in con-tact lens science and technology have eliminated orminimised many of the complications that pre-dateddisposable lenses. Most of those complications wereassociated with deposition of denatured protein andother lens contaminants, giving rise to auto-immune

reactions, mechanical irritation of the tarsal conjunc-tiva and other ocular tissue, and in some cases, con-siderable discomfort. Loss of lubricity and increasedfriction as a result of lens surface contamination werelikely responsible for these adverse ocular surface re-actions. As lens technology continues to advance it isimportant to measure the friction not only of freshlenses but to determine how lens friction changes inresponse to wearing time and surface deposits.

One of the more dramatic ocular complicationsthat typifies the above description is giant papillaryconjunctivitis (GPC) or what is now termed contactlens papillary conjunctivitis (CLPC). GPC was firstreported by Thomas Spring in 1974 as an inflamma-tory reaction of the palpebral conjunctiva more oftenobserved on the upper lid.13 Large (or “Giant”) papil-lae, palpebral hyperaemia and mucus secretion arecharacteristic of the condition.14 Symptoms includeitching, ocular discomfort and poor, variable visionwhich frequently led to discontinuation of wear. Itwas not uncommon to observe an apparently dehy-drated contaminated lens move 4 or 5 mm with anormal blink, obviously due the loss of lubricity be-tween the lens and palpebral surfaces. With currentlenses and good habits of frequent replacement thesefindings are quite rarely encountered.

Through the development phase of silicone hy-drogel lenses, CLPC has been reported to occurmore frequently (especially with continuous wear)than with conventional hydrogel lenses and less withnewer silicone hydrogels than first generation.15 Inaddition to the design and modulus changes, onewould have to suspect that increased water contentand methods to retain surface moisture has helped todecrease the incidence of CLPC.

Coincident with the development of silicone hydro-gel lenses, new clinical conditions have been reported.In 2002, Korb and colleagues described a conditioncalled lid-wiper epitheliopathy (LWE) which is a bandof affected tissue of the marginal conjunctiva of the up-per eyelid that wipes the ocular surface. The conditionis diagnosed by staining with fluorescein, rose bengalor lissamine green. They found that contact lens wear-ers who were symptomatic of dryness had a significant-ly higher percentage of lid-wiper staining compared toasymptomatic wearers.16

Pult and colleagues described a condition calledlid-parallel conjunctival folds (LIPCOF) which aresub-clinical folds of the bulbar conjunctiva above andparallel to the lower lid margin.17 It appears that thiscondition is also more prevalent in symptomatic con-tact lens wearers but can also be detected in patientswith dry eye who do not wear contact lenses.

L U B R I C I T Y


The suspected etiology of both LWE and LIP-COF is mechanical and in the case of LWE, thetarsal conjunctiva is subjected to increased frictionalforce or reduced lubricity of the contact lens surfacecausing micro trauma to epithelial cells. This couldbe aggravated by a lack of lubrication from tears.The factor these more subtle contact lens relatedconditions appear to have in common with GPC ap-pears to be reduced lubricity, which probably pro-vokes the symptoms of discomfort and dryness.

Efforts to Increase LubricityA number of attempts to increase the wettability of thelens or to retain its moisture during the wearing periodappear to have been somewhat successful. Examples ofincorporating wetting agents into lens materials arepolyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP)and hyaluronic acid. These substances have also beenused in artificial tears and contact lens rewetting drops.PVP acts as a hydrophilic layer thereby shielding thehydrophobic properties of silicone hydrogel lenses.Other humectants (substances that help to retain water)such as hydroxypropyl methylcellulose (HPMC) andpolyethylene glycol (PEG) have been shown to im-

prove wettability of silicone hydrogel lenses. Keir andJones have eloquently and more extensively describedthis topic.18 However it is unknown whether these wet-ting agents have had a lasting effect on lubricity.

The most recent development in daily disposablesilicone hydrogel technology is termed a water gradi-ent lens*, ranging from 33% water content in thecore to approximately 80% at the surface.19,20 Gel lay-ers that are minimally crosslinked (5-6 µm thick) aregraded on the surfaces of silicone hydrogel contactlenses.20 Sawyer concluded that these gel layers pro-vide a lubricious surface with very low friction coeffi-cients (below µ = 0.01).

Finally, the most compelling evidence of a mea-sureable lens variable that correlates with end-of-daycomfort is the coefficient of friction, demonstratedby Brennan and Coles in two separate studies.21,22 Theefforts of measuring and modifying lens surfaces thattruly retain moisture and lubricity throughout theday could be the most important development sincethe Wichterle soft lens, perhaps even surpassing thediscovery of the silicone hydrogel material. CLS

*Based on in-vitro measurement of unworn lenses.

L U B R I C I T Y

12. Tighe BJ. A decade of silicone hydrogel development: surfaceproperties, mechanical properties and ocular compatibility.Eye Contact Lens 2013;39(1):4-12.

13. Spring TF. Reaction to hydrophilic lenses. Med J Aust1974;1(12):449-450.

14. Allansmith MR, Korb DR, Greiner JV, Henriquez AS, SimonMA, Finnemore VM. Giant papillary conjunctivitis in con-tact lens wearers. Am J Ophthalmol 1977;83(5):697-708.

15. Dumbleton K. Noninflammatory silicone hydrogel contactlens complications. Eye Cont Lens 2003;29(1 Suppl):S186-189;discussion S190-191, S192-194.

16. Korb DR, Greiner JV, Herman JP, et al. Lid-wiper epithe-liopathy and dry-eye symptoms in contact lens wearers.CLAO J 2002;28(4):211-216.

17. Pult H, Purslow C, Berry M, Murphy PJ. Clinical tests forsuccessful contact lens wear: relationship and predictive po-tential. Optom Vis Sci 2008;85(10):E924-929.

18. Keir N, Jones L. Wettability and silicone hydrogel lenses: Areview. Eye Contact Lens 2013;39(1)100-108.

19. Pruitt J, Qiu Y, Thekveli S et al. Surface characterization of awater gradient silicone hydrogel contact lens (delefilcon A).Invest Ophthal Vis Sci 2012; 53. E-abstract 6107.

20. Sawyer WG. Lubricity in high water content surface gel lay-ers. Optom Vis Sci 2012;89. E-abstract 125089.

21. Brennan, N.A., Contact Lens-based correlates of soft lenswearing comfort. Optom Vis Sci 2009;86. E-abstract 90957.

22. Coles C. Coefficient of friction and contact lens comfort. Op-tom Vis Sci 2012;89. E-abstract 125603.

References1. Dumbleton K, Woods CA, Jones LW, Fonn D. The impact

of contemporary contact lenses on contact lens discontinua-tion. Eye Contact Lens 2013;39(1):93-99.

2. Rumpakis J. New data on contact lens dropouts: an interna-tional perspective. Review of Optometry 147; 2010: 37-42.

3. Fonn D, Situ P, Simpson TL. Hydrogel lens dehydrationand subjective comfort and dryness ratings in symptomaticand asymptomatic contact lens wearers. Optom Vis Sci1999;76(10):700-704.

4. Guillon M, Maissa C. Dry eye symptomatology of soft con-tact lens wearers and non-wearers. Optom Vis Sci2005;82(9):829-834.

5. Chalmers RL, Begley CG. Dryness symptoms among an un-selected clinical population with and without contact lenswear. Cont Lens Anterior Eye 2006;29(1):25-30.

6. Cedarstaff TH, Tomlinson A. A comparative study of tearevaporation rates and water content of soft contact lenses. Am J Optom Physiol Opt 1983;60(3):167-174.

7. Pritchard N, Fonn D. Dehydration, lens movement and dry-ness ratings of hydrogel contact lenses. Ophthalmic Physiol OptMorgan PB, Efron N. In vivo dehydration of silicone hydro-gel contact lenses. Eye Contact Lens 2003;29(3):173-176.

9. Subarraman L, Jones LW. Measuring friction and lubricityof hydrogel contact lenses – A review. Contact Lens Spectrum;Special edition 2013 (in press).

10. Malhotra M, Subramanian R, Gahlot P, Rathore B. Text-book in Applied Mechanics. New Delhi: New Age Interna-tional; 1994.

11. Maldonado-Codina C, Efron N. Dynamic wettability ofpHEMA-based hydrogel contact lenses. Ophthalmic PhysiolOpt 2006;26(4):408-418.


Measuring Friction andLubricity of Soft ContactLenses: A Review

Over the last 35 years, the numberof contact lens wearers worldwide hasincreased from 10 million to 140 mil-lion, with the vast majority (over90%) being fitted with soft lenses.1Recent reports suggest that the con-tact lens industry is healthy and theworldwide annual soft contact lensmarket is estimated at $5.3 billion,with the U.S. market estimated at$1.9 billion.2 However, despite thisapparently buoyant position, manywearers continue to be dissatisfiedwith their lenses and approximately35% of lens wearers discontinue wear,with the majority reporting the majorreasons being discomfort and dryness,particularly at the end of the day.3Contact lens-related discomfort anddryness is influenced by several fac-tors, and likely include both the inter-action of the posterior surface of thelens with the corneal surface and theanterior surface of the contact lenswith the posterior surface of the eye-lid during the blink.

Hydrogel lenses rapidly attract var-ious components from the tear film,particularly proteins and lipids, fol-lowing their insertion.4 These can re-

sult in alterations to the surface of thecontact lens that can change the fric-tional forces that exist during blink-ing. Furthermore, dehydration oflenses can result in increased lid-lensinteraction due to a reduction in lensfront-surface wettability and lubricity,and the development of corneal ep-ithelial staining due to pervaporationand subsequent desiccation.5 Studieshave suggested that the frictionalproperties of contact lenses may alsobe associated with certain clinicallyobservable phenomena, notably lidwiper epitheliopathy and lid parallelconjunctival folds.6,7 Finally, increasedfriction may lead to contact lens asso-ciated papillary conjunctivitis due tothe mechanical interaction of thepalpebral conjunctiva with the contactlens surface.8

Issues such as these have made itclear that the frictional properties oflenses are an important design consid-eration in the fabrication and manufac-ture of soft lenses. Furthermore,understanding the frictional forces thatoccur at the lens surface will provideinsight into the relationship betweenthe lens material surface properties and

Dr. Jones is a Professor at theSchool of Optometry and Vision Science and Director of the Centre for Contact LensResearch at the University ofWaterloo. He is aconsultant/advisor to Alconand Johnson & Johnson. He has received grants from Alcon,Allergan, Bausch + Lomb,CooperVision, Johnson & Johnson, TearScience, Essilorand Visioneering.

Comfort may be tied to friction and lubricity.

E X P L O R I N G C O M F O R T

B y L a k s hm a n N S u b b a r am a n , P h D , B SO p t om , M S c , F A AO ,& L y n d o n W J o n e s , P h D , F CO p t om , F AAO

Dr. Subbaraman is Head of Biological Sciences at the Centre of Contact Lens Research, School of Optometry,University of Waterloo. He is aconsultant/advisor to Alconand Johnson & Johnson. He has received grants from Alcon,Allergan, Bausch + Lomb,CooperVision, Johnson &Johnson, TearScience, Essilorand Visioneering.


MORE POWERFOR GREATER SUCCESS

Alcon off ers the DAILIES® family of daily disposable contact lenses and the AIR OPTIX® family of monthly replacement lenses. Multiple studies have shown that daily disposable and monthly replacement contact lenswearers are more compliant* than those who wear 2-week lenses.2,3,4 Compliant patients also return for more eye examinations.1

Compliant* Patients Come In For More Eye Exams.1

Alcon Can Help Bring Patients Back.

Read more about this latest study, and see how Alcon can boost your practice, at myalcon.com/power-of-one*Compliance with Manufacturer-Recommended Replacement Frequency (MRRF).

References: 1. Dumbleton KA, Richter D, Jones LW. Compliance with lens replacement and the interval between eye examinations. Optom Vis Sci. 2012;89 (E-abstract 120059). 2. Dumbleton K, Woods C, Jones L, et al. Patient and practitioner compliance with silicone hydrogel and daily disposable lens replacement in the United States. Eye & Contact Lens. 2009;35(4):164-171. 3. Yeung KK, Forister JFY, Forister EF, et al. Compliance with soft contact lens replacement schedules and associated contact lens–related ocular complications: The UCLA Contact Lens Study. Optometry. 2010; 81(11):598-607. 4. Dumbleton K, Woods C, Jones L, et al. Comfort and Vision with Silicone Hydrogel Lenses: Eff ect of Compliance. Optom Vis Sci. 2010;87(6):421-425.

See product instructions for complete wear, care, and safety information.

© 2012 Novartis 8/12 POW12060JAD


81924 POW12060JAD CLS.indd 1 5/9/13 6:06 PM

biological responses such as protein deposition andbacterial adhesion.9 However, to-date, very few studiesreport on the frictional characteristics of soft lenses10-16and contact lens practitioners may be unaware of therelevance of this factor to everyday practice. Thescope of this review article is to provide an overview ofvarious methods that have been employed to deter-mine the friction of hydrogel lenses.

TerminologyMaterial scientists and researchers who work on the sur-face properties of lens materials commonly use termssuch as “tribology”, “friction” and “lubricity.” However,eye care practitioners may not be familiar with theseterms as they do not use them on a day-to-day basis anda description of these terms is valuable.

Tribology comes from the Greek word “tribos,”which means “to rub.” Tribology is generally definedas the study of three areas — friction, lubrication andwear. These three areas are highly inter-related; how-ever, the relationship between friction and wear is notwell understood. Generally, friction is producedwhen two sliding surfaces come into contact, result-ing in wear. Wear can be prevented by lubrication,and the separation of the surfaces by a lubricant willresult in a reduction in friction. The purpose of tribo-logical research is to minimize friction and wear,therefore, tribology plays a major role in the effectivetreatment of some of the common medical conditionsinvolving bodily implants and joint diseases.

Biotribology is a relatively new term introducedin the early 1970s to describe a group of sciences thatfocus on one single topic — the study of friction,wear and lubrication within biology. This is a multi-disciplinary subject covering the areas of engineer-ing, material science, biological science, physicalscience and medicine.

Friction can be defined as the force that acts atthe surface of two solid surfaces to resist sliding overone another. The force that prevents one surfacesliding over the other is quantified by a simple indexcalled the coefficient of friction (CoF). In order todetermine CoF, two measurements are needed: (a)the force required to initiate and/or sustain slidingand (b) the normal force holding the two surfaces to-gether. CoF can then be calculated by dividing theinitiating/sustaining force by the normal force. A lu-bricant can be used to reduce friction between twosurfaces. Since a lubricant reduces friction, CoF is aneasy measure of quantifying the lubricating ability ofany system. Generally, a comparison between CoFgenerated by an instrument under identical condi-tions is acceptable. However, comparing CoF values

from different instruments under different condi-tions should be interpreted with caution.

Lubrication is defined as any means capable ofcontrolling friction and wear of interactive surfacesin relative motion. There are two types of lubrica-tion; one where there is a solid-to-solid contact ofthe sliding surfaces is known as “boundary lubrica-tion” and the other where there is a thin layer of flu-id that is present in the intervening space(hydrostatic lubrication) or the motion produces alayer of fluid on which the moving surface planesover the counter face (hydrodynamic lubrication).

Methods of Measuring Friction and LubricityThe most common method for determining the CoFof soft contact lenses is through the use of a “microtri-bometer.” Some researchers have used a methodbased on atomic force microscopy15,16 and others havedeveloped novel proprietary techniques17 to determinethe lubricity of contact lenses and the following sec-tion describes these various methods.

MicrotribometerA microtribometer is an instrument that directlymeasures the frictional force and the normal force inorder to calculate the coefficient of friction. Manydifferent parameters must be controlled to generaterepeatable measurements and the following sectionprovides an outline of the parameters that influencethe CoF values obtained using a microtribometer.

Sliding speed: Test speeds have a large effect onthe measured COF and speeds as low as 0.01 mm/sec13

have been used to measure “boundary lubrication”,which occurs when the lens is in direct contact with



Biotribology is a relativelynew term introduced in theearly 1970s to describe agroup of sciences that focuson one single topic — thestudy of friction, wear andlubrication within biology.

the ocular tissues. Higher speeds approximating theblink speed of 12 cm/sec have been used10 to measure“mixed” or “hydrodynamic lubrication”, where a thinfluid film separates the contact lens from the oculartissues. Studies have used a wide range of slidingspeeds (63 to 6280 µm/sec,11 0.01 to 0.5cm/sec,12 or 10 to 600 µm/sec18) to determine the effect of slidingspeeds on the reported CoF values.

Normal Force Pressure: In-vivo eyelid pressuresare typically estimated at 1-7 kPa and achieving accu-rate force measurements at these low pressures can bechallenging. A recent study has determined frictionalvalues at very low contact pressures, approaching1kPa.18

Substrate / Counter Surface: All friction mea-surements involve two surfaces and the choice ofsubstrate against which to determine the CoF can af-fect the reported results. Substrates utilized includeglass,11,18 stainless steel,12 or mucin-coated silanizedglass.13

Lubricating fluid: Nairn and colleagues10 usedvarious commercial ophthalmic solutions includingB+L ReNu, Allergan Complete, Alcon Opti-Freeand B+L saline and showed that differing lubricantsresulted in differences in the reported CoF values.Artificial tear fluids and solutions containing a vari-ety of tear proteins that mimic human tears have alsobeen used as lubricating fluids.13,14

Type of movement: Microtribometers typicallyuse either a flat plate or a curved probe that is movedacross the lens surface. The flat plate method main-tains contact with only a single point on the contactlens surface during testing,13 while the probe methodis able to expose fresh lens surface to the probe as the

probe is moved across the lens surface.18Lens sample preparation: To-date, all published

CoF data has been conducted only on unwornlenses. The effects of lens wear and contact lens caresolutions have not been adequately tested in order todetermine whether the coefficient of friction is likelyto change with time after exposure to tear film com-ponents and further work is warranted in this area.

Finger Lubricity MethodRecently, a qualitative “finger rubbing” method hasbeen described to determine contact lens lubricity.17In this method, contact lenses were rinsed overnightin a phosphate buffered saline (PBS) solution to re-move any packaging solution, and the investigatorrubbed the lens between their thumb and index fin-gers and the lubricity was rated on a 0 (most lubri-cious) to 4 (least lubricious) scale. The advantage ofthis method is that it is a simple, quick method thatdoes not require any sophisticated instrumentation.The authors reported that this method was highlyrepeatable, but only when used by an experienced in-vestigator.17 A major disadvantage of this method isthat it is a limited qualitative scale and not all lenstypes can be differentiated with this technique.

Inclined Plane Method (Figure 1)This is a novel, quantitative method of determiningcontact lens friction using a PBS solution.17 In thismethod, a clean glass plate is adjusted to a desiredangle in a PBS bath. The contact lens under test isplaced at the top of the glass plate and a 0.8 gramstainless steel ferrule (0.88 kPa) is placed on the lensto initiate movement. A minimum critical angle is


Figure 1. Inclined plane method


determined, which maintains the movement of thelens over a distance of approximately 100 mm. Thetangent of the critical angle is a measure of the kinet-ic coefficient of friction. Thus, in this method, thetangent of the largest angle where the lens is unableto maintain movement will determine the kinetic co-efficient of friction.17

Atomic Force Microscopy (Figure 2)Atomic force microscopy (AFM) is a standard tech-nique used to study the surface topography of con-ventional and silicone hydrogel contact lensmaterials.19 AFM is a very powerful tool for high-res-olution examination of the contact lens surface andalso permits the analysis of surface topography androughness by means of a non-destructive methodolo-gy. AFM consists of a microscale cantilever with asharp tip, which scans the surface of the lens. Thecantilever is typically made of silicon or silicon ni-tride with a tip radius of curvature in the order ofnanometers. The AFM can be operated in a numberof modes, including static (also called contact) modeand a variety of dynamic (non-contact or tapping)modes, where the cantilever is vibrated. The advan-tage of AFM over traditional microscopic techniquesis the high-resolution, three-dimensional images andalso that topographic information can be obtained in

several conditions (such asaqueous, non-aqueous ordry), thereby eliminatingthe need for sample prepa-ration.

Kim and colleagues15,16used a contact-mode AFMto determine the surfaceproperties of pHEMA-based soft contact lenses.AFM images of the lenssurface were taken in twoconditions: (a) with thelens surface exposed to air(“surface-dehydrated”) and(b) in the presence ofsaline solution on the lenssurface. After successfullyoptimizing a method toquantify friction usingAFM, the authors conclud-ed that the friction forceimaging of the “surface-dehydrated” soft contactlenses made of cross-linkedpHEMA showed low fric-

tion at the surfaces. In saline, the surface friction wassignificantly reduced compared to those measuredfor the “surface-dehydrated” lens.15 In a recent study,Rudy and colleagues20 determined the surface me-chanical and tribological properties of silicone hy-drogels using AFM. In this study, they measured theelastic modulus by indenting a probe into the surfaceof the hydrogel in a controlled manner and obtaineda modulus value by fitting the characteristic forceversus indentation behaviour. Their results showedthat pHEMA-based etafilcon A lenses have a modu-lus between 100 and 130 kPa, whereas balafilcon Alenses were an order of magnitude higher in value.The frictional properties followed a similar trend,with plasma surface-treated lenses (such as balafilconA) exhibiting CoF values five times those of dele-filcon A water gradient silicone hydrogels. Thesestudies show that the elastic modulus and frictionalproperties of different hydrogel and silicone hydro-gel lenses can be evaluated at a nanoscopic level us-ing AFM.

ConclusionsDetermining the frictional properties of soft lenses iscomplicated and a review of the literature revealsthat there are several methods of determining the lu-bricity of contact lens materials. Due to the vast dif-


Figure 2. Beam Deflection AFM


(Im

ag

e c

ou

rte

sy

Un

ive

rsit

y o

f F

lori

da

)

ference in techniques and methodology for deter-mining friction, there are noticeable differences inthe coefficient of friction values published to-date.Though significant differences do seem to existamong lens materials, it remains challenging to makecomparisons until standard methods of testing areagreed upon. Material chemistry, water content, testmedia, applied load and the sliding velocity all havean impact on the results, and may impact differentmaterials to varying degrees. Deposition of tear-de-rived components can also impact friction forces forboth silicone and conventional hydrogels and may bea difficult condition to reproduce in an in vitro test-ing model and future studies should include testingunder conditions closer to that obtained in-eye.

A recent analysis that attempted to correlate severalcontact lens material-related properties (Dk/t, modu-lus, water content and lubricity) with end-of-daywearing comfort found coefficient of friction to be the

principal physical property associated with comfort.21In this work, end-of-day comfort data obtained fromover 700 separate 1-month wearing trials were derivedusing a sensitive and sophisticated method. The fric-tion data showed consistently high correlation withcomfort, implicating that coefficient of friction couldbe a major driving factor in subjective comfort. How-ever, data from more carefully conducted clinical trialsare needed to determine the relationship between sub-jective symptoms of discomfort and dryness and thelubricity of various commercial contact lens materials.The influence of contact lens care regimens and howthey influence the friction values of contact lensesshould also be investigated. CLS

The authors would like to acknowledge Alcon LaboratoriesLtd, USA for their support in developing this articlethrough an unrestricted grant.


1. Morgan PB, Woods CA, Tranoudis IG, et al. Internationalcontact lens prescribing in 2011. Contact Lens Spectrum;January 2012.

2. Nichols JJ. Contact Lenses 2008. Contact Lens Spectrum;January 2009.

3. Fonn D. Targeting contact lens induced dryness and dis-comfort: what properties will make lenses more comfort-able. Optom Vis Sci 2007;84(4):279-285.

4. Bontempo AR, Rapp J. Protein and lipid deposition ontohydrophilic contact lenses in vivo. CLAO J 2001;27(2):75-80.

5. Pritchard N, Fonn D. Dehydration, lens movement anddryness ratings of hydrogel contact lenses. OphthalmicPhysiol Opt 1995;15(4):281-286.

6. Berry M, Pult H, Purslow C, Murphy PJ. Mucins and ocu-lar signs in symptomatic and asymptomatic contact lenswear. Optom Vis Sci 2008;85(10):E930-938.

7. Pult H, Purslow C, Berry M, Murphy PJ. Clinical tests forsuccessful contact lens wear: relationship and predictivepotential. Optom Vis Sci 2008;85(10):E924-929.

8. Donshik PC. Contact lens chemistry and giant papillaryconjunctivitis. Eye Contact Lens 2003;29(1 Suppl):S37-39;discussion S57-59, S192-194.

9. Willcox MD, Harmis N, Cowell BA, Williams T, HoldenBA. Bacterial interactions with contact lenses; effects oflens material, lens wear and microbial physiology. Biomate-rials 2001;22(24):3235-3247.

10. Nairn JA, Jiang T. Measurement of the friction and lubric-ity properties of contact lenses. In: Proceedings of AN-TEC 1995; May 7-11, 1995 in Boston.

11. Rennie AC, Dickrell PL, Sawyer WG. Friction coefficientof soft contact lenses: measurements and modeling. TribolLett 2005;18(4):499-504.

12. Zhou B, Li Y, Randall NX, Li L. A study of the frictionalproperties of senofilcon-A contact lenses. J Mech BehavBiomed Mater 2011;4(7):1336-1342.

13. Roba M, Duncan EG, Hill GA, Spencer ND, Tosatti SG.Friction measurements on contact lenses in their operatingenvironment. Tribol Lett 2011;44:387-397.

14. Ngai V, Medley JB, Jones L, Forrest J, Teichroeb J. Fric-tion of contact lenses: silicone hydrogel versus convention-al hydrogel. Tribol Interface Eng Ser 2005;48:371-79.

15. Kim SH, Marmo C, Somorjai GA. Friction studies of hy-drogel contact lenses using AFM: non-crosslinked poly-mers of low friction at the surface. Biomaterials2001;22(24):3285-3294.

16. Kim SH, Opdahl A, Marmo C, Somorjai GA. AFM andSFG studies of pHEMA-based hydrogel contact lens sur-faces in saline solution: adhesion, friction, and the presenceof non-crosslinked polymer chains at the surface. Biomate-rials 2002;23(7):1657-1666.

17. Tucker RC, Quinter B, Patel D, Pruitt J, Nelson J. Quali-tative and quantitative lubricity of experimental contactlenses. Invest Ophthalmol Vis Sci 2012;ARVO E-Ab-stract:6093.

18. Sawyer WG, Dunn AC, Uruena JM, Ketelson H. Robustcontact lens lubricity using surface gels. Invest OphthalmolVis Sci 2012;ARVO E-abstract:6095.

19. Gonzalez-Meijome JM, Lopez-Alemany A, Almeida JB,Parafita MA, Refojo MF. Microscopic observation of un-worn siloxane-hydrogel soft contact lenses by atomic forcemicroscopy. J Biomed Mater Res B Appl Biomater2006;76(2):412-418.

20. Rudy A, Huo H, Perry S, Ketelson H. Surface mechanicaland tribological properties of silicone hydrogels measuredby atomic force microscopy. Invest Ophthalmol Vis Sci2012;ARVO E-abstract:6114.

21. Coles C, Brennan N. Coefficient of friction and soft con-tact lens comfort. Optom Vis Sci 2012;89:E-abstract:125603.


References

There’s never been a better time to do something about macular health.*

ICaps® Lutein and Omega-3 Vitamin Help:• PROTECT the retina with lutein1*

• PROMOTE macular health2*

• SUPPORT the natural defense system of the eye3*

Once- Daily

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

ICaps® L&O Vitamins have ingredients studied in AREDS2. It’s the only once daily softgel with 10 mg of Lutein, 2 mg of Zeaxanthin and benefi cial levels of Omega-3s to help support macular health.*

Recommend ICaps® Lutein & Omega-3 Vitamin to your patients before another minute goes by.

Visit icapsvitamins.com to learn more.

© 2013 Novartis 2/13 ICP13001JAD FloraGLO is a registered trademark of Kemin Industries, Inc.

References: (1) Richer S, Stiles W, Statkute L, et al. Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial). Optometry. 2004;75:3-15. (2) SanGiovanni JP, Chew EY, Clemons TE, et al. The relationship of dietary lipid intake and age-related macular degeneration in a case-control study. AREDS Report No. 20. Arch Ophthalmol. 2007;125:671-679. (3) Chiu CJ, Taylor A. Nutritional antioxidants and age-related cataract and maculopathy. Experimental Eye Research. 2007;84:229-245.


82415 ICP13001JAD CLS.indd 1 5/22/13 3:27 PM

Introducing WaterGradient Technology

Contact lens materials haveevolved from PMMAlenses of the 1950s tooxygen permeable rigidlenses of the 1980s and

beyond. The introduction of hydrogelmaterials in the early 1970s broughtnew levels of comfort. Disposable lens-es in the 1990s evolved further with theintroduction of silicone hydrogels.Material and manufacturing technolo-gies have made possible daily dispos-able lenses, something that would havebeen unthinkable in the early days ofsoft lenses.

As materials evolved, it became use-ful to find a way to group these materi-als based on fundamental characteristicsincluding water content and the pres-ence of ionic ingredients for hydrophilicmaterials and by the hydrophobic com-ponents for the rigid hydrophobic ma-terials1. By 1994, FDA listed 34different soft contact lens materials and95 brands and 39 hydrophobic contactlenses.1 These grouping systems servedthe industry well through the both thehydrophobic lens and hydrogel lenseras, but with the introduction of sili-cone hydrogel materials, the system hadto be expanded to include these biphasicmaterials.

A New EraSince the introduction of silicone hy-drogels in 1998, these materials havebecome the dominant choice of fittingpractitioners.2,3 Today these materialsare considered to be a separate class ofhydrophilic contact lens materials andexperts from around the world areevaluating if additional groups areneeded.4 The latest introduction,Dailies Total1 (delefilcon A) watergradient daily disposable contact lens-es by Alcon Laboratories, represents alandmark in the continuing revolutionin contact lens materials that under-scores the need for a new groupingsystem, because this material is trulyin a class by itself as the first watergradient silicone hydrogel contactlens.

Dailies Total1 daily disposablecontact lenses have a revolutionarystructure based on a silicone hydrogelcore and a water gradient surface thatcreates a transition from core watercontent of 33% to a surface watercontent in excess of 80% at the inter-face with the tear film. The surface ofthe lens, like the corneal epitheliumand glycocalyx, has a brush-like struc-ture that binds water in this region ofthe lens. A water gradient is created

Dr. Stone is one of the foremost experts on contactlens care product design andformulation. A winner of theprestigious Donald KorbAward from the AmericanOptometric Association, Contact Lens & Cornea Section, he is often referredto as the father of moderncontact lens care. Dr. Stone is a former VP of researchand development for Alcon.

Daily disposable contact lenses with water gradienttechnology represent a new era in contact lens wear.

M A T E R I A L S

B y R a l p h S t o n e , P h D


by cross-linked polymeric wetting agents that form asoft, hydrophilic surface gel, which is embedded intothe core, creating a smooth transition from the coreto the surface. The water gradient provides the low-est silicone surface content of any silicone hydrogellens material.

Figure 1 shows a representation of this novel ap-proach.5 Figure 2 shows an Atomic Force Microscopy(AFM) image of a cross section of the lens demon-strating the change in material properties from thecore to the surface. With a center thickness of 90 mi-

crons, the water gradient surface represents slightlymore than 6% of the central lens thickness on eachside.6

The color change in the AFM image represents achange in water content, modulus and chemical com-position that is not seen in any other lenses tested. Thewater gradient provides a lubricous lens surface that isalso substantially softer than the core of the lens.6

Beyond OxygenWith the development of materials and lens care sys-tems over time, we have recognized that we can solvesome of the issues of contact lens lenses and lens wearwith improved technologies. The understanding of therole of oxygen and transmission through the lens hasled to the creation of lenses that do not cause oxygendeficiency at the cornea. It is now recognized that en-hanced oxygen maintains corneal function and decreas-es edema and other changes due to hypoxia. DailiesTotal1 lenses have a central Dk/t of 156 at -3.00diopters. This is the highest of the currently availabledaily disposable contact lens materials. Table 1 shows acomparison of Dk and central Dk/t of several daily dis-posable lens materials.

Oxygen has not solved all contact lens wear issues.Despite advances made in lens materials to date, ithas been reported that nearly 15% percent of pa-tients will stop wearing contact lenses every year.7The most common reasons reported for discontinu-ing wear are discomfort and dryness.8-11

Enhancing Comfort: Modulus, Wettability, LubricityThree primary approaches have been suggested toenhance comfortable wear of contact lenses: provid-ing a low modulus hydrogel surface, maintainingwettability throughout the day, and minimizing thefriction of the lid crossing the front lens surface.

The water gradient of Dailies Total1 lenses addressthe modulus challenge by providing a soft, cushioninglayer on the outer surface of lens. This can be mea-sured using an AFM modulus scan (Figure 3).5

In addition to the modulus gradient observed in theAFM scan, there is an ultra-soft surface gel on theoutermost surface of the lens. The high water contentat the surface provides an extremely wettable interfacewith the tear film. Measurements by Menzies andJones12 showed Dailies Total1 lenses had lower ad-vancing and receding contact angles, as measured by asessile drop, than other tested daily disposable contactlenses with the exception of nelfilcon A (Dailies AquaComfort Plus contact lenses).

Wettability is only one measure of ways to help

M A T E R I A L S

Figure 1. Schematic representation of Dailies Total1 watergradient contact lenses.

Figure 2. Atomic Force Microscopy cross-section image ofthe Dailies Total1 contact lens.


keep contact lenses comfortable. Brennan reportedthat lubricity as measured by coefficient of friction ishighly correlated to comfort (r=0.90, p<0.01).13 Korband colleagues14 reported that there is a correlation(p<0.00001) between lid wiper epitheliopathy and dry-ness symptoms associated with wear of contact lenses.In studies of 105 symtomatic and asymptomatic lenswearers, Korb and colleagues14 found 80% of sympto-matic patients showed the presence of lid wiper stain-ing compared to 13% of asymptomatic patients withinthe first 4 hours of wear.

The novel water gradient surface of the DailiesTotal1 lenses provides a highly lubricious surface.Contact lenses can provide hydrodynamic lubricationduring the fastest part of a blink as the tear film ismaintained between a contact lens and the eyelid. At

lower ocular movement speeds, however, a contactlens is in direct contact with the ocular tissues result-ing in much higher friction. The soft, high water sur-face of the Dailies Total1 lenses acts as a boundarylubricant during these low speed ocular movementsproviding excellent lubricity (low coefficient of fric-tion). Measurements by Sawyer and co-workers15found that the coefficient of friction of Dailies Total1lenses was comparable to or even lower than the coef-ficient of friction of epithelial cells. Additional qualita-tive and quantitative methods have been used toestimate the lubricity (or its inverse the coefficient offriction) and have demonstrated the highly lubriciousnature of the Dailies Total1 lenses.16 When measuringthe lubricity or friction of Dailies Total1 lenses it isimportant to utilize pressures similar to those found in

M A T E R I A L S

Comparison of Oxygen Permeability and Transmissibility of Daily Disposable Lens Materials

T a b l e 1

Comparison of Ocular Physiology* and Surface Appearance of Two Silicone Hydrogel Daily Disposable Lenses and Dailies Total1Daily Disposable Lenses with a Water Gradient Surface.

T a b l e 2

Dailies Total1 Clariti 1-Day p value Acuvue TruEye p valueContact lenses Contact lens compared Contact lenses compared(delefilcon A) (7ettab II 3) to Dailies (narafilcon A) to Dailies

Total1 Total1lenses lenses

Corneal Staining (0-10,000) 25+54 38+ 70 p<0.01 74+ 117 p<0.01Conjunctival Staining (0-100) 4+ 5 30+ 12 p<0.01 10+ 8 No differencePL-NIBUT (seconds) 5.7 4.7 p<0.01 4.7 p<0.01Graded wettability compared to Dailies Total1 lenses .27 p<0.01 .34 p<0.01Difference in observed deposition compared to Dailies Total1 lenses .31 p<0.01 .13 p<0.01

*Mean plus/minus standard deviation

Lens Material Dk Dk/t**

Delefilcon A (Dailies Total1 contact lenses, Alcon) 140* 156Narafilcon A (Acuvue TruEye, Johnson & Johnson Vision Care – not available in US) 100 118Narafilcon B (US version Acuvue TruEye, Johnson & Johnson Vision Care) 55 65Etafilcon A(1-Day Acuvue Moist, Johnson & Johnson Vision Care) 28 33Omafilcon A (Proclear 1 Day, CooperVision) 33 36Nesofilcon A (Biotrue, Bausch + Lomb) 42*** 42

*Alcon data on File 2010 **Dk/t calculated using manufacturer’s published center thickness for -3.00 diopter lenses when available. Others as published in Tyler’s Quarterly***Data from FDA 510(k) K113703 Summary June 6, 2012


1. FDA Premarket Notification (510(k)) Guidance for Daily Wear Con-tact Lenses, May 12, 1994:p24-25.

2. Nichols JJ, Contact Lenses 2011. Contact Lens Spectrum, January 2012;27:20-25.

3. Morgan PB, Woods CA, Tranoudis IA, et al. International ContactLens Prescribing in 2011. Contact Lens Spectrum, January 2012; 27:25-31.

4. ISO 18369-1:2006/Amd 1:2009(E) Ophthalmic Optics-Contact LensesPart 1. Vocabulary, Classification System and Recommendations forLabelling Specifications.

5. Pruitt JP, Yongxing Qui, Thekeli S, Hart R. Surface characterization ofa water gradient silicone hydrogel contact lens (delefilcon A). Invest Oph-thalmol Vis Sci2012; 53: e-abstract 6107.

6. Thekveli S, Qui Y, Kapoor Y, et al. Structure property relationship ofdelefilcon A lenses. Poster 41 presented at BCLA 2012.

7. Rumpakis JMB. New data on contact lens dropouts: An internationalperspective. Review of Optometry2010;147(11):37-42.

8. Weed K, Fonn D, Potvin R. Discontinuation of contact lens wear. Optom Vis Sci1993;70:140.8.

9. Pritchard N, Fonn D, Brazeau D. Discontinuation of contact lens wear:a survey. Int Contact Lens Clin1999;26:157-162.

10. Richdale K, Sinnott LT, Skadahl E, Nichols JJ. Frequency of and fac-tors associated with contact lens dissatisfaction and discontinuation.Cornea2007;26:168-74.

11. Young G, Veys J, Pritchard N, Coleman S. A multi-centre study oflapsed contact lens wearers. Ophthalmic Physiol Opt2002;22(6):516-527.

12. Menzies K, Jones L. Sessile drop contact angle analysis of hydrogel andsilicone hydrogel daily disposable and frequent replacement contactlenses. Cont Lens Ant Eye2012; BCLA abstract 35.

13. Brennan NA. Contact lens-based correlates of soft lens wearing com-fort brennan na, contact lens-based correlates of soft lens wearing com-fort. Optom Vis Sci2009;86:E-abstract 90957.

14. Korb DR, Greiner JV, Herman JP, et al. Lid wiper epitheliopathy anddry eye symptoms in contact lens wearers. CLAO2002;28(4):211-216.

15. Sawyer WG, Dunn AC, Uruena JM, Ketelsen HA. Robust contactlens lubricity using surface gels. Invest Ophthalmol Vis Sci 2012;53:e-abstract 6095.

16. Tucker RC, Quinter B, Patel D, et al. Qualitative and quantitative lu-bricity of experimental contact lenses. Invest Ophthalmol Vis Sci2012;53:e-abstract 914.

17. Angelini TE, Dunn AC, Uruena JM, Ketelson H, Sawyer WG. Stressinduced frictional transitions in cross-linked surface gels. Invest Ophthal-mol Vis Sci2012;53(E-abstract 6113).

18. Keir NJ, Varikooty J, Richter D. Evaluation of lens surface appearanceand ocular physiology with three silicone hydrogel daily disposables.Cont Lens Ant Eye2012; BCLA abstract 15.

19. Varikooty J, Keir N, Richter D, et al. Subjective comfort with three sili-cone hydrogel daily disposables in symptomatic contact lens wearers.Cont Lens Ant Eye2012; BCLA abstract 21.

the eye (<7 kPa) because the surface of the lenses is sosoft that higher pressures could actually crush the sur-face giving erroneous test results.17

Of course the presence of a water gradient, highoxygen permeability, low surface modulus, enhancedsurface wettability and low friction/high lubricity areonly really meaningful if they impact clinical perfor-mance. Keir and colleagues18 reported recently on aclinical trial with 104 subjects using Dailies Total1

lenses and two competitive silicone hydrogel daily dis-posable lenses. While the other daily disposable lenstested were acceptable, Dailies Total1 lenses showedthe least impact on ocular physiology and the leastchange in lens surface appearance when evaluated after8 hours of wear. The results are shown in Table 2.

In a separate report by Varikooty and colleagues,19the subjective comfort of 53 enrolled symptomatic pa-tients from this study was evaluated. The comfort wasmeasured at 4, 8 and 12 hours. At each time pointDailies Total1 lenses was numerically superior to othersilicone hydrogel daily disposable contact lenses.

ConclusionDailies Total1 lenses provide a new concept in

contact lenses combining the benefit of a high per-meability oxygen silicone hydrogel core and a watergradient transition from the low water silicone hy-drogel core to a high water content surface. Thisnew technology is made possible by the next genera-tion of Alcon’s patented LightStream Lens Technol-ogy. The high water surface provides a low modulus,highly wettable and lubricious surface. This revolu-tionary technology does not fit the current classifica-tion approaches for either the conventionalhydrophilic lens materials or the biphasic siliconehydrogels, and stand alone as a novel approach tocontact lens chemistry. CLS

M A T E R I A L S

Modulus shown as the average of 20 linear scans from core to surface (AFM modulus scan-excludes outer0.5 microns); Alcon data on file 2011.

Figure 3. Modulus comparison of a cross section of DailiesTotal1 contact lenses.


References

T 3, 6, AND 9 O’CLOCKA SCRIBE MARKS

DESIGN TM8|4PRECISION BALANCE

STABILIZED HERESTABILIZED HERE

39

6

TIONA≤5º OF OSCILL

STABILIZED 8 4

PERMANENT PLASMA SURFACE TECHNOLOGY

Engineered for sustained performance

© 2013 Novartis 12/12 AOT13001JAD

PRECISION BALANCE 8|4™

1

2,3

4

IS THE CORE OF OUR DESIGN

STABILITY

Important information for AIR OPTIX® for Astigmatism (lotra� lcon B) contact lenses:

References: 1. 2.

3. Optom Vis Sci4.

AIR OPTIX® for Astigmatism

myalcon.com ®


80924 AOT13001JAD CLS.indd 1 1/14/13 4:23 PM

The Development ofDailies Total1 WaterGradient Contact Lenses

The development of thedelefilcon A lens materialthat makes up DailiesTotal1 contact lenses began more than 10 years

ago and involved a dedicated multi-nationalteam of scientists, engineers andclinicians. Early in the develop-ment, the team had many intensediscussions about what lensproperties should be targeted inorder to create the most com-fortable contact lens possible.The team quickly recognized themany limitations and trade-offsinherent in relying on a singlebulk material.By way of analogy, it is known that

the cornea is comprised of differenttissue layers, each with their ownunique anatomical structure and phys-iological function. When integratedinto one organ, these layers performmultiple functions, for example, lightrefraction, mechanical support and-physiologic protection of the eye.When selecting a target water con-tent, the R&D team recognized fromour experience with silicone hydrogel

materials that a low water contentmaterial with high levels of siliconewould provide excellent oxygen trans-missibility, good handling characteris-tics and resistance to dehydration.Conversely, from our experience with

(non-silicone) traditional hydrogelmaterials, we knew that extremelyhigh water content materials withoutsilicone could provide excellent wetta-bility, lubricity, and resistance to lipidfouling.The R&D team recognized that an

extremely low modulus may make alens easier to fit and help provide improved comfort but at the cost ofdecreased lens handling performance.There also seemed to be a limit to

N E W P R O D U C T

B y J o h n P r u i t t , P h D a n d E r i c h B a um a n , OD , F AAO

Research led to a departure from using a single bulkmaterial for the whole lens.

Dr. Bauman is project headfor Dailies Total1 projectswithin Vision Care Research& Development at Alcon Laboratories, Inc. He receivedhis doctor of optometry degree with honors from theSouthern California Collegeof Optometry in 1982 and an MBA from Coles Collegeof Business in 2001.

Dr. Pruitt is Project Head,Biocompatibility Projects forAlcon Vision Care R&D. Hereceived his PhD in ChemicalEngineering from BrighamYoung University.

The surface coefficient of friction, or lubricity, has been shown to havea high correlation withlens comfort scores.


how soft one can make a lens material. The modulusof corneal epithelial cells1 is less than 0.02 MPa andit seemed impossible to make a contact lens materialas soft as that without it simply falling apart.Following the paradigm of using multiple materials

as in the cornea, we realized that some of these properties, such as oxygen transmissibility and lenshandling, could be controlled by a lens ‘core’ materialwhile other properties like wettability and lubricitywere only important at the surface. A lens with onlya single water content, modulus or chemistrywould always entail some level of compromise.The team arrived at the question: “whyshould patients have to settle for the same water content at the core and surface, or indeed the same material chemistry at the coreand surface of a lens?” This led to a radicaldeparture from single bulk material thinkingand formed the basis for the development ofthe delefilcon A water gradient lens material.

Revolutionary ChangeA measurable change can be demonstrated in the lensmaterial, the water content and the modulus of dele-filcon A from core to surface. This represents the first-ever water gradient contact lens designed to feature anincrease from 33% to more than 80% water contentfrom core to surface. To enable this water gradient,the delefilcon A lens material transitions from a highly

breathable silicone hydrogel material at the core to anon-silicone hydrophilic polymer structure at the surface (Figure 1). This enables a lens with a Dk/t of156 (at the center of a -3.00D lens) combined with asurface-water content of over 80%,1 as seen in Figure 2.A gradient occurs between the two areas in which thewater content rapidly increases and the material shiftsfrom a silicone-rich core material to an essentiallysilicone-free surface gel.2 This surface material formsan ultrasoft surface gel and makes up about 10% of the

lens thickness. While the average water content of theultrasoft surface gel exceeds 80%, the water gradientstructure allows the water content to approach almost100% at the outermost surface of the lens.3Several laboratory techniques have measured this

change in lens material properties including AtomicForce Microscopy (AFM), Neutron Reflectometry,and Fluorescent Laser Confocal Microscopy.2 These

N E W P R O D U C T

Figure 1. Cross section illustration of Dailies Total1 water gradient contact lens

A measurable change can be demonstrated in the lensmaterial, the water content and the modulus of delefilcon Afrom core to surface.


* Dk/t at center of -3.00D lens based on manufacturer-published values.** Core water content and lens overall water content are both 33% ± 2%.† Water content for competitor lenses are manufacturer-published lens overall water contents.

methods demonstrate the gradient in modulus andother lens properties across the lens cross section,not seen in other lens materials.The modulus of the lenses also changes with the

material becoming much softer at the surface of thelens with the outer surface having a compressionmodulus of only about 0.025 MPa.4 The modulus ofthe lens core is maintained at 0.7 MPa for excellentinsertion handling. The surface modulus of dele-filcon A is almost as soft as the corneal epithelialcells1,5 yet this ultrasoft surface gel is able to maintainits integrity because it is supported by the lens corematerial. In a similar manner the ultrasoft cornealepithelial cells are supported by collagen fibrils, giv-ing the cornea an overall bulk modulus that is muchhigher than the modulus of the individual cells.

Highly Breathable Daily Disposable Lens Why do we need such a high Dk/t for a daily dispos-able contact lens? There are several factors to con-sider. Stated Dk/t values (and even theoretical flux orequivalent oxygen estimations) are normally provid-ed only for the center of a -3.00D lens. The greaterperipheral lens thickness means oxygen transmissi-

bility is lower with minus powers, but in plus powers,the central oxygen transmission values will be lowerthan the stated value for -3.00D. Figure 3 illustratesthis with the color oxygen maps across the wholelens in different materials and powers. The blue endof the spectrum is used to indicate high Dk/t and redshows areas of lower Dk/t. It has become apparentthat a single Dk/t value isn’t sufficient to completelycharacterize the oxygen transmission in contact lenses. Furthermore, the published Dk/t values forthe lenses only represent a small portion at the center of a -3.00D lens. The peripheral oxygentransmissibility is generally much lower as seen inthe colored maps. Research demonstrates that peripheral oxygen transmission is equally importantto ocular health as that in the center.6 In addition,different patients have different oxygen demands,some of which may not be predictable during a routine examination, even when using a slit lamp.7Thus, starting with the highest available central Dk/tvalue is in the best way to avoid hypoxic concernsand meet the needs of various patient lifestyles.Oxygen transmissibility in delefilcon is largely deter-

mined by the core of the lens because it comprises the

N E W P R O D U C T

Figure 2. The delefilcon A lens material transitions from a highly breathable silicone hydrogel material at the core to anon-silicone hydrophilic polymer structure at the surface, allowing for a lens with a Dk/t of 156 (at the center of a -3.00Dlens) combined with a surface-water content of more than 80 percent.


majority of the lens thickness. Of particular interest arethe unique properties at the surface of the lens, becausethese are key to a comfortable lens-wearing experience.

The Importance of Surface Lubricity The comfort of a contact lens may be influenced bymany factors ranging from the modulus of the mate-rial, lens thickness, and water content to lens designand parameters. The surface coefficient of friction, orlubricity,8 has been shown to have a high correlationwith lens comfort scores. Lubricity is the inverse offriction and, for a contact lens, is described as howeasily the components of the ocular surface, such asthe palpebral conjunctiva, can slide across the lenssurface. We blink about 14000 times per day.9 Witheach blink, the superior lid has to slide down, thenback up over the lens surface. As such, it makes sensethat lubricity is highly predictive of lens comfort. Lu-bricity can be detected with the fingers as a slipperyfeeling and it can be measured by using either an in-clined plane or a micro tribometer.10 Regardless of

N E W P R O D U C T

the method used to measure lubricity, it is importantthat the pressures reflect those found in the ocularenvironment — in other words, matching those ex-erted by the eyelid against the lens on eye). This is es-pecially important when measuring the lubricity ofdelefilcon A because the extremely soft water gradi-ent surface structures can be artificially crushed ifmeasured at pressures that exceed those found in theeye thereby giving erroneous lubricity results at hightesting pressures.11 Using kinetic coefficient of friction, measured by the

inclined plate method, delefilcon A has been shown tohave extremely low friction (excellent lubricity).5 A new contact lens with different core and surface

properties meant that detailed research was neededto optimize the chosen design parameters. Numer-ous studies were conducted to co-optimize the basecurve, diameter and lens design. Ultimately, thecombination of an 8.5mm base curve with a 14.1mmdiameter was selected to give optimal centration andlens movement. The full technical specifications and

Note: Dk/t at center of -3.00D lens and Dk are based on manufacturer-published values.

Figure 3. Oxygen transmissibility in delefilcon is largely determined by the core of the lens because it comprises the majority of the lens thickness.


swelling?. Eye Contact Lens 2003;29(1 Suppl):S7-S9;discussionS26-29, S192-194.

8. Brennan NA. Contact lens-based correlates of soft lens-wear-ing comfort. Opt Vis Sci Abstract 90957, November 2009.

9. Inoue K, Okugawa K, Amano S, et al. Blinking and superfi-cial punctate keratopathy in patients with diabetes mellitus.Eye (Lond). 2005;19(4):418-421.

10. Subarraman L, Jones LW. Measuring friction and lubricityof hydrogel contact lenses – A review. Contact Lens Spectrum;2013 (in press).

11. Angelini TE, Dunn AC, Uruena JM, Ketelson H, SawyerWG. Stress induced frictional transitions in cross-linked sur-face gels. Invest Oph Vis Sci 2012;53(E-abstract 6113).

12. Keir N, Richter D, Varikooty J, Jones L, Woods C, Fonn D.End of day comfort using a novel cumulative comfort score.Invest Oph Vis Sci 2012;53(E-Abstract 4728).

13. Varikooty J, Keir N, Richter D, Jones L, Woods C, Fonn D.Subjective comfort with three silicone hydrogel daily dispos-ables in symptomatic contact lens wearers. BCLA AnnualClinical Conference, 2012.

range of parameters can be seen inTable 1.

Exceptional ComfortThroughout the DayThe outcome of this superior lubricity is outstanding wearer comfort through the end of the day.In a clinical study with 104 subjects,cumulative comfort scores were su-perior for Dailies Total1 contactlenses in comparison with other silicone hydrogel daily disposablelenses.12 In a group of 53 sympto-matic subjects, 100% of them couldwear Dailies Total1 contact lensesfor at least 8 hours and 85% wereable to wear them up to 12 hours.In comparison to their habituallenses, the majority of the subjectswere able to wear Dailies Total1contact lenses for clinically signifi-cant longer periods of time.13

The Start of a New EraSince soft contact lenses were first introduced, therehave been numerous incremental changes to materials to improve water retention and wearercomfort. Ciba Vision introduced the first siliconehydrogel contact lens in 1998, ushering in a new erain lens material technology that has triggered extensive steps to improve oxygen transmission forpatients worldwide. The creation of the first water

References1. Straehla J, Limpoco F, Dolgova N, Keselowsky B, SawyerWG. Tribology Letters 2010;38(2):107-113.

2. Thekveli S et al. Structure-property relationship of delefilconA lenses. BCLA Annual Clinical Conference, 2012.

3. Angelini TE, Nixon RM, Dunn AC, Uruena JM, Pruitt J,Sawyer WG. Viscoelasticity and mesh-size at the surface ofhydrogels characterized with microrheology. Invest Oph VisSci 2013;54(E-Abstract 500).

4. Dunn A, Urueña J, Huo Y, Perry S, Angelini T, Sawyer WG.Lubricity of surface hydrogel layers. Tribology Letters2013;49(2):371-378.

5. Rudy A, Huo Y, Perry SS, Ketelson H. Surface mechanicaland tribological properties of silicone hydrogels measured byatomic force microscopy. Invest Oph Vis Sci 2012;53(E-Ab-stract 6114).

6. Papas E, Willcox M. Reducing the consequences of hypoxia:the ocular redness response. Contact Lens Spectrum, specialedition 2006; pages 32-37.

7. Bonanno JA, Nyguen T, Biehl T, Soni S. Can variability incorneal metabolism explain the variability in corneal

Dailies Total1 Parameters & technical specifications

T a b l e 1

Material Delefilcon A Surface Water Content (%) >80% Base Curve (mm) 8.5Center Thickness (mm) (-3.00D) 0.09Core Water Content (%) 33%Dk/t 156 @ -3.00D Core Modulus (MPa) 0.7Packaging 5 (trials), 30 pack, 90 packDiameter (mm) 14.1Handling Tint VISITINT lens Manufacturing Newest generation of LightStream

Technology enables the creation of the water gradientLenses contain phosphatidylcholine, an ingredient also found in natural tears.

Power Ranges (at launch) Diopters -0.50 to -6.00 (in 0.25 steps)

-6.50 to -10.00 (in 0.50 steps)

See product instructions for complete wear,care, and safety information

N E W P R O D U C T

gradient contact lens, featuring an increase from33% to over 80% water content from core to surface, marks the start of yet another new era incontact lenses, and with it, hope for a new era incomfort for contact lens wearers around the world. CLS

Editor’s note: A similar article appeared in the April 5, 2013 edition of Optician.


Some SurfaceS are worth protecting

THE OCULAR SURFACE IS ONE.

© 2012 Novartis 10/12 SYS13100JAD

References1. Christensen MT, Blackie CA, Korb DR, et al. An evaluation of the performance of a novel lubricant eye drop. Poster D692 presented at: The Association for Research in Vision and Ophthalmology Annual Meeting; May 2-6, 2010; Fort Lauderdale, FL. 2. Davitt WF, Bloomenstein M, Christensen M, et al. Efficacy in patients with dry eye after treatment with a new lubricant eye drop formulation. J Ocul Pharmacol Ther. 2010;26(4):347-353. 3. Data on file, Alcon. 4. Wojtowica JC., et al. Pilot, Prospective, Randomized, Double-masked, Placebo-controlled Clinical Trial of an Omega-3 Supplement for Dry Eye. Cornea 2011:30(3) 308-314. 5. Geerling G., et al. The International Workshop on Meibomian Gland Dysfunction: Report of the Subcommittee on Management and Treatment of Meibomian Gland Dysfunction. IOVS 2011:52(4).

Surface Protection and More

The SYSTANE® portfolio includes products that are engineered to protect, preserve and promote a healthy ocular surface1-5. See eye care through a new lens with our innovative portfolio of products.


82414 SYS13100JAD CLS.indd 1 5/22/13 3:27 PM

GroundbreakingTechnology Debuts inDaily Disposable Market

Dr. Eiden: Today, we’ll share ourexperiences with what we believe is arevolutionary new contact lens tech-nology. The Alcon Dailies Total1lens was designed to address some ofthe key challenges we still face in dailypractice in a way that we haven’t beenable to do before, relating to all-daycomfort, visual performance andbreathability. Let’s begin by dis-cussing some of those challenges.

Number One ComplaintDr. Eiden: Dr. Brujic, do you al-

ways know when patients are dissatis-fied with their habitual contact lenses?

Dr. Brujic: I see two types of chal-lenging patients. The first is the non-complaining patient, and the second isthe habitually complaining patient.The non-complainers seem to haveno problems, but often, I thinkthey’re reluctant to complain, becausethey’re concerned they’ll have to stopwearing contact lenses.

Dr. Eiden: How do you help thesepatients open up?

Dr. Brujic: I ask them to rank thequality of their vision and the comfortof their lenses, each on a scale from 0 to 10. Many people who tell metheir comfort is “fine” or “great” give

their lenses a grade that is less thanthe 10 I’d expect for comfort that is“fine.” This is a huge opportunity forme to introduce new technologies tothese patients, as well as to patientswho do verbalize their complaints.

Dr. Eiden: Dr. Jasper, do you findthe same thing happening in yourpractice? Do you see it as an opportu-nity to make changes for your pa-tients?

Dr. Jasper: Absolutely. The mostcommon complaint I hear is that pa-tients can’t wear their lenses as longas they want to during the day. Whena patient tells me this, it’s my job tofind out why. Typically, it’s becausethe lenses are not comfortable, or thepatient’s lenses feel dry. Another chal-lenge is the patients who tell us whatthey think we want to hear just tomake us happy.

Dr. Eiden: What do you do whenyou suspect a patient is just tellingyou what you want to hear?

Dr. Jasper: I help them get pastthat by rewording my questions. Imay ask, “What’s the longest amountof time you can wear your lensescomfortably during the day?” or“How often do you switch to youreyeglasses before the end of the day?”

Panelists discuss a unique new lens that has surprisingcharacteristics designed to defeat discomfort.

R O U N D T A B L E D I S C U S S I O N

S. Barry Eiden, OD, FAAO(moderator)

Mile Brujic, OD

April Jasper, OD, FAAO

Jordan Kassalow, OD

Kelly Nichols, OD, MPH, PhD,FAAO

John L. Schachet, OD

This roundtable discussionwas held during SECO 2013.For complete biographiesand disclosures, please seepage 52.


Dr. Eiden: Dr. Nichols, what questions do youask your patients to uncover any comfort issues?

Dr. Nichols: I always ask patients how manyhours a day they wear their lenses, how many hoursthey want to wear them and what things they’ve triedto eliminate some of their discomfort. In my prac-tice, I see patients who are having more significantissues. Many of these patients are former contact lenswearers who really want to wear them again. I thinksometimes we’re quick to say, “You’re done withcontact lenses,” instead of trying something new.When patients start to drop out in their 30s or 40s,we need to try to figure out if we can do somethingto keep them comfortable in lenses, because theywant to wear them.

Dr. Eiden: Other issues that concern us in termsof contact lens performance include ocular health response and visual response. Dr. Schachet, how im-portant are these aspects in comparison to comfortissues?

Dr. Schachet: They’re all important and inter-related. Most of my patients who have discomforthave either a dryness problem, which can be accom-panied by fluctuating vision, or they’re not using theideal lens care solution for their lenses. So, whetherwe’re talking about initial comfort or end-of-daycomfort, I look at those two things primarily before

looking at anything else. We have to be proactive,and we need to listen. When we listen carefully towhat patients say, the problem often becomes appar-ent even before we go to our instrumentation.

Unmet Needs in Daily DisposablesDr. Eiden: Dr. Kassalow, you fit a significant

number of daily disposable lenses. What impact hasthis modality had on your practice?

Dr. Kassalow: The four areas I always focus onwhen discussing contact lenses with patients arecomfort, convenience, vision and health. Daily dis-posable lenses hit each of those areas square on.From my experience, daily disposable lenses are themost comfortable modality, and patients who wearthem are my happiest group of patients. When I seea patient who’s wearing daily disposable lenses, Iknow that 9 out of 10 times, it will be a relativelyeasy office visit.

Dr. Eiden: How do they rate their vision?Dr. Kassalow: They’re just as happy with their

vision, because every day, they have a fresh lens.The lens is wet and clean, and they like that. Theyalso love the convenience. They don’t have to usecare solutions and feel like a chemist every night.

Dr. Eiden: And health?Dr. Kassalow: My patients and I both love the


DStart With Staff to Build Excitement

r. Eiden: Educating our staff members about new technology is critical to be successful in bringingnew technologies to our patients. How have you educated your staff about Dailies Total1 technology?

Dr. Brujic: The best way to educate your staff is to have those who are contact lens wearers try thelenses, so they can share their excitement and their experiences.

Dr. Jasper: After you’ve explained the benefits of the lens, how amazing it is and how fortunate weare to have it available to us, then watch to see to whom they recommend the lens first. Usually, it’stheir friends and family. That tells you they believe in it. They’ve tried it, and they want the people theylove most to be the first to have it.

Dr. Kassalow: I’m fortunate to have staff members who have been with my practice for many years.They know most of my patients, and my patients trust them. I’ve noticed an interesting phenomenonwith the Dailies Total1 lenses. In the past, staff members might talk about their cool eyeglasses, but theywould never talk about their contact lenses. Now, patients are asking for Dailies Total1 lenses based onthe enthusiasm of the staff members who are wearing them. Making new lens technology an emotionalexperience speaks volumes, particularly when the experience is relayed by someone who is trusted, suchas staff members.

Dr. Eiden: I agree wholeheartedly that the experience is where it’s at. I do think, however, that shar-ing the science is equally important. Our technical staff always want to know the science behind things.So we include it as part of our office meetings. Our staff understands the technology and has bought intothis concept.


fact that daily disposable lenses are a healthy option.The modality has been a fantastic practice-builder.Overall, my patients are happier than they were before they started wearing daily disposables.

Dr. Eiden: Where do you see opportunity for ad-vancement in daily disposable lenses?

Dr. Kassalow: Despite having many daily dispos-able lenses, we still have a group of patients whoaren’t comfortable wearing them, so I’m excitedabout the Dailies Total1 lens and the advent of thisnew technology. I think it will fundamentally shiftthe comfort curve.

Dr. Jasper: I think it all comes back to the onething we’ve discussed so far. Discomfort is still an is-sue for some patients. I still have patients who tellme they can wear their lenses for only 6 hours a day.

New and Unique PropertiesDr. Eiden: Dailies Total1 technology is truly rev-

olutionary, because it’s totally different from anyother material. It’s the first water gradient siliconehydrogel lens. Dr. Brujic, what is meant by watergradient and how is this lens different from any oth-er HEMA or silicone hydrogel lens?

Dr. Brujic: Dailies Total1 lenses are manufac-tured in a new silicone hydrogel material called dele-filcon A, which is designed to enable a gradualtransition from 33 percent water at the core of thelens to over 80 percent at its surface. Amazingly, thishappens in a 6-micron space.

Dr. Nichols: All contact lenses aim to simulate theocular surface and conform to the environment of thetears in a way that enhances the tears or at least doesn’tharm anything about the tears — almost as though thelens isn’t there. In short, the Nirvana of contact lenswear is to have no lens awareness. A number of studieshave shown that changes to the ocular surface tissuesare highly associated with symptomatic contact lenspatients.1,2 This lens has a surface that mimics the nat-ural hydrophilic ocular surface.

Dr. Eiden: Dr. Kassalow, how do you explain theconcept of lubricity to your patients?

Dr. Kassalow: I always talk about lubricity as afeature of the lens. Different patients have appetitesfor different amounts of information, so to some pa-tients, I say, “This is the single best, most comfort-able lens I’ve worked with in my 25-year career.Let’s try it,” and they say, “Great. Let’s do it.” Oth-ers may tell me they’re comfortable with their cur-rent lenses and ask for more information. For them,I focus on how lubricity equates to comfort.

Dr. Schachet: What’s nice about this lens is thatthe lid has no effect on it because it virtually glides

over water. That’s another point that makes it easierfor patients to understand.

Dr. Eiden: Handling a contact lens can be a chal-lenge for some patients. We always talk about theconvenience of daily disposables, but I’ve had pa-tients reject them simply because they were difficultto handle. Dr. Jasper, tell us about the modulus gra-dient and how that influences lens handling.

Dr. Jasper: Dailies Total1 lenses have a low-modulus surface, which enhances comfort, and ahigh modulus core, which facilitates ease of han-dling. I proactively explain to patients how I wantthem to apply and remove these lenses. I think themost noteworthy characteristic, especially for pa-tients who have worn lenses all their lives, is that af-ter applying the lens, they hardly know it’s there —except that they can see. Lens removal may be some-what challenging for some patients. I instruct themto be sure their hands are thoroughly dry before theyremove the lenses.

Dr. Eiden: The same attribute that makes thelens so lubricious makes it somewhat difficult to re-move if your fingers are wet, because it just slidesright over the lens surface.

Dr. Brujic: I refit a patient who’d been wearinganother brand of daily disposable lenses into DailiesTotal1 lenses. When he tried to remove them bypinching them off of his cornea, he had some trou-ble. After I explained how to remove these lenses —the slide-and-pinch technique — and that he washaving trouble because of how slick the lens surfaceis, he suddenly said, “Wow, now I really understandwhy this is such a comfortable lens.”

Highest Dk/t in a Daily DisposableDr. Eiden: With a Dk/t of 156 (@–3.00D),

Dailies Total1 lenses have the highest oxygen trans-missibility of any daily disposable lens. Assumingperfect compliance, do you think the cornea needsthis much oxygen?

Dr. Schachet: Each patient’s requirement for oxy-gen is different, but I don’t think there’s anythingwrong with aiming for high oxygen transmissibility.

Dr. Jasper: We don’t know every reason whypeople drop out of contact lenses. People say dis-comfort and dryness, but it seems to me if you pro-vide them with the most oxygen throughout alifetime of contact lens wear, they’ll have fewerproblems. As Dr. Schachet mentioned, we don’tknow what each individual’s unique oxygen need is.It depends on their lens, where they live, what theydo, and so on, so going high in my mind is not a badthing.



Dr. Brujic: It used to be a more relevant argu-ment when we were trying to decide between oxy-gen transmissibility and wettability. With theDailies Total1 lens technology, we don’t have togive up either.

Dr. Jasper: I tell my patients, “I want to give youa contact lens that is like having nothing on youreye.” In other words, we want a lens that’s the leastlike a lens, and I would hope that every companythat works with contact lenses would strive to dothat for our patients.

Dr. Eiden: That is a powerful statement. Why dowe put a contact lens on anybody’s eye? To help themsee better. So, the more that it’s like nothing, otherthan vision correction, the better it is for our patients.

Personal ExperiencesDr. Eiden: We’ve discussed many of the attribut-

es that make Dailies Total1 unique and exciting.Most of us have had the opportunity to wear theselenses. I’d like to get your personal feedback onwearing these lenses.

Dr. Nichols: I’m the perfect example of a patientlooking for a more comfortable daily disposable lens.I’m probably always going to have some comfort is-sues, because I work long hours late at night on thecomputer. I’ve worn Dailies Total1 lenses for about6 months, and I can wear these lenses longer andmore comfortably than any other daily disposablelens that I’ve worn.

Dr. Schachet: Overwhelmingly, this is the mostcomfortable lens I’ve ever had on my eye, and that isdirectly attributable to the water gradient. When it’son the eye, you don’t even know you’re wearing a con-tact lens. It’s the most incredible lens-wearing experi-ence I’ve had in all the years I’ve been practicing.

Dr. Nichols: Our patients deserve the chance totry these lenses. I don’t think people recognizethey’re uncomfortable until they experience com-fortable.

Dr. Eiden: More than a year ago, I had my firstexposure to this technology in Europe. At the end ofmy first day wearing the lens — we sat down to din-ner at about 11:00 p.m. — I realized I still had thelenses on, but I didn’t feel them. That’s never hap-pened to me before. Usually after 3 or 4 hours, Ihave to peel the lenses off of my eyes.

We’ve recounted our personal experiences.Now, let’s discuss how our patients are reacting toDailies Total1 lenses.

Patients’ ExperiencesDr. Brujic: One of the high moments for me as a

clinician is putting lenses on eyes at the beginning oflens wear, because that sets a precedent in a patient’smind of how that lens will perform. The beautifulthing about the Dailies Total1 lens is its excellentinitial comfort.

Dr. Eiden: Dr. Jasper, you had an anecdote youwanted to share.

Dr. Jasper: One of my patients, a teenager, waswearing another lens, apparently successfully, but Iwanted her to try the Dailies Total1 lenses. As soonas she put them on her eyes, she said, “Oh my good-ness. I had no idea my contacts were supposed to feellike this.” She didn’t really understand how to an-swer my questions about comfort, but once she expe-rienced the “no-lens” feeling, she understood what itwas really supposed to be like.

Dr. Kassalow: When a patient comes in happyand with the attitude “if it ain’t broke, don’t fix it,”it’s easy for us to buy into that, because it makes ourday go more smoothly. When contemplating achange for one of these patients, I sometimes askmyself, “Am I setting myself up for headaches? Am Islowing down my day? Am I inconveniencing the pa-tient?” Sometimes, my inclination is to just leavewell enough alone. Every person on whom I’ve triedthe Dailies Total1 lens has had a positive experience.It doesn’t create that backlash of having to try a dif-ferent lens and repeat the cycle. That’s an importantdynamic in my practice that will prompt me reachfor this lens frequently. It’s not creating more workfor me. It’s making my day go faster, and I’m puttingpatients into a premium product.

Dr. Nichols: I like the idea that it streamlinesyour process, because you’re not trying a lens thatmight be uncomfortable. You’re confident this lenswill be successful.

Dr. Eiden: We have to constantly present newtechnologies and reinvent ourselves to give patients areason to come to see us regularly. For that reason,I’ve presented these lenses to happy patients who ap-parently have no problems. I say, “Yes, I know every-thing is great, and if you want to continue with yourcurrent lenses, you can, but I want you to test-drivesome new technology.” I’ve found that these patientsdo see an improvement. It may not be as dramatic asthe improvement seen by symptomatic patients, butthey still see a bump up.

Dr. Brujic: That’s the true test of good technolo-gy: taking an asymptomatic patient, someone whohas no problems, and improving his experience. Thislens is giving us the ability to do just that.

Dr. Kassalow: I’ve definitely seen that happen.Several hundred of our patients are wearing a com-



petitor’s product that is being discontinued. Wemailed them information, letting them know theproduct would no longer be available, and we invitedthem to come in and try the Dailies Total1 lens.Four out of five of the people who have tried thislens so far have said, “Wow, thanks, doc. This is bet-ter than I knew I could have.”

Dr. Schachet: Another patient whom we haven’tdiscussed is the new contact lens wearer. Anyonewho’s never worn a contact lens has an opinion ofhow it will feel on their eyes. When new wearers tryDailies Total1 lenses, they’re amazed, because theydon’t even know it’s there.

Dr. Nichols: That’s a good point. Why not startwith innovative technology rather than “fix” a problem?Many patients are accustomed tonew technology in other aspectsof their lives.

Dr. Eiden: That’s an inter-esting perspective. We’re “fix-ing” so many of our patientsbecause they have contactlens-associated problems. Thistechnology takes us to a wholenew level in terms of preven-tion — having patients startwith a great lens so they canstay with it for a long time.

Dr. Schachet: Even thoughthis is the closest to a perfectlens we have, we have to re-member that some patientswill have dryness issues. If wedon’t address that, they won’tbe able to wear the lenses allday.

Dr. Kassalow: That’s agreat point. Even though weall believe this technology is aquantum leap forward, we stillneed to assess issues that couldlead to contact lens-associated dryness.

Dr. Nichols: I agree. When there’s an underlyingcondition, a lens can’t make that go away. We needto evaluate the ocular surface and lids at every visitand manage the findings appropriately, even for apatient who says everything is “fine.”

Value Versus CostDr. Eiden: From my perspective, Dailies Total1

lenses are for everybody whose prescription fits theparameters. Do you agree? Will this lens be a prob-lem-solver or a go-to lens in your practice?

Dr. Kassalow: I will clearly position Dailies To-tal1 contact lenses as a go-to, first-reach lens. It is apremium lens with a premium-lens price, so somepeople may push back because of the cost and staywith products that are less expensive. In those cases,I’ll use it as a problem-solver when appropriate.

Dr. Eiden: How have patients responded so far tothe higher cost of this new technology?

Dr. Schachet: Reactions have been mixed sofar. It wouldn’t be fair to say it has been acceptedoverwhelmingly; however, I recently had an in-teresting case. Some long-time patients came inwith their sons, ages 13 and 15 years. They hadbeen wearing contact lenses, but not very com-fortably. When they tried Dailies Total1 lenses,

both boys had an over-whelmingly positive experi-ence. This was the first timethey’d been able to wearcontact lenses all day. I ex-plained the cost to their par-ents. I guess they went homeand thought it over, because3 days later, they called andordered Dailies Total1 lens-es for both boys.

Dr. Eiden: Practitioners of-ten wonder: Should we orshouldn’t we discuss the costbefore the patient experiencesthe lens? I’ve decided I wantmy patients to experience thelens first. I do mention the costis a bit higher, but I tell pa-tients, “I don’t want to talkabout the cost now, because Idon’t want that to influencehow you respond to this lens. Ijust want you to experience it.If your experience is as positiveas I expect it to be, then we’ll

have that conversation. You can decide if the value isworth the price.”

Dr. Jasper: I think patients hear “new technolo-gy” and “innovative contact lens,” and they know itwill cost more. I’m okay with that. I’m not going toprejudge a patient’s ability or willingness to pay for apremium product. Those of us who have opticals,encourage our staff to present the best frames toeverybody, so why would we not present the bestmedical device to everybody. In the end, patientsknow I did not prejudge them, and I treated themlike my best friend and my family.


If you design yourmarketing properlyand let people know this truly is arevolutionary newcontact lens, there’sabsolutely nothinglike it anywhere in theworld, I think you’ll havequite a few peoplecoming in to try it.

— John L. Schachet,OD


Patient Support Program

Give your glaucoma patients the help they need.

For more information go to professional.openingsprogram.com

Reminders • Education • Personalized plans • Hands-on tools • Savings

It can be diffi cult to know who among your patients will follow your prescribing instructions and who won’t. That’s why there’s the OPENINGS™ Patient Support Program from Alcon — a proven partnership in patient support.

Proven to impact refi ll persistency 1*A recently concluded study demonstrated that patients enrolled in the OPENINGS™ Program who used the savings card fi lled an average of two additional prescriptions compared to those not enrolled in the program. Those who enrolled but did not use the savings card or may not have used it because they participate in a government-funded savings program, fi lled an average of one additional prescription a year. In light of this, make the OPENINGS™ Program part of your patient care plan.

A TRUE PARTNER IN PROVIDING GLAUCOMA PATIENT SUPPORT

You’ve diagnosed your patient, provided advice and presented a treatment plan.

But what happens when he or she goes home?

© 2013 Novartis 1/13 MG13016JAD

References: 1. Cognizant - OPENINGS™ Program Consumer ROI Study, September 2012.* Online quantitative survey with patients currently using active ingredient The Test group

consisted of 220 patients enrolled in the OPENINGS™ Program while the Control group included 151 patients not enrolled in the OPENINGS™ Program and not using the Alcon

Savings Card. Statistical testing was performed at the 95% Confi dence Interval.


82417 MG13016JAD CLS.indd 1 5/22/13 3:28 PM


Groundbreaking TechnologyDr. Eiden: What does the introduction of Dailies

Total1 lenses mean to you and your practice?Dr. Nichols: If everyone’s experience is similar to

my own with this lens — being able to wear it com-fortably longer than any other daily lens, havingminimal lens awareness, yet maintaining good quali-ty vision — then this technology is going to impactthe daily market. I think it could revolutionize howwe think about the technology behind daily dispos-able contact lenses, and how we select lens optionsfor patients, including patients with comfort issues.

Dr. Schachet: This is a unique lens that shouldbe in a category all alone. There isn’t anything like itanywhere. When my patients try it, I simply say, “Ifthis lens isn’t the most comfortable lens you’ve everput on, I’d like to hear why.”

Dr. Kassalow: We’ve learned that almost 50 per-cent of people who stop contact lens wear do so be-cause of discomfort issues,3 and I can’t assume thatmy practice is any different. If we can reduce thatnumber in our practices, it will have a ripple effectand help us grow exponentially. I think it’s going tohave a huge impact on my practice, because fewerpatients will leave contact lens wear.

Dr. Brujic: We’re taking comfort to the next lev-el with this lens, and I think that’s an exciting placeto be, because comfort is an unmet need in our pa-tient populations. We now have this new tool to helpus keep more patients in contact lenses.

Dr. Jasper: I’m excited about this lens, because,to me, it means I have a slam-dunk, a lens that willtake care of my patients’ needs. I love being able totell my patients, “I’m going to give you the best lensin every category. It’s also going to give you the bestvision.” This lens makes me look good, and it makesmy patients extremely happy.

Dr. Eiden: Dailies Total1 lenses representgroundbreaking technology that will enable us to ad-dress our patients’ comfort and vision needs — thewhole package. I know I speak for the panel when Isay we’re honored to have been part of the initialgroup of practitioners to have access to this technol-ogy and to experience it. Now, it will be equally asexciting for us to share it with our colleagues. CLS

S. Barry Eiden, OD, FAAO (moderator)Dr. Eiden is president and medical director of NorthSuburban Vision Consultants Ltd. with offices in Deerfield and Park Ridge, Ill. He reports no financialdisclosures.

Mile Brujic, ODDr. Brujic is a partner in Premier Vision Group, a four-location practice in northwest Ohio. He is a consultant/advisor to Alcon, Allergan, Nicox,TelScreen, Transitions, Valeant Pharmaceuticals,

Vmax Vision and Valley Contax. He has received research support from Alcon and VMax. He has lectured and/or received honoraria from Alcon, Allergan, Vmax and Valley Contax.

April Jasper, OD, FAAODr. Jasper practices at Advanced Eyecare Specialists in West Palm Beach, Fla. She is a consultant/advisorto Alcon, Eyefinity and Marco. She has lectured or re-ceived honoraria from Konan and Carl Zeiss Meditec.

Jordan Kassalow, ODDr. Kassalow is a partner at Farkas, Kassalow andResnick in New York City, N.Y. He reports no financialdisclosures.

Kelly Nichols, OD, MPH, PhD, FAAO, Dipl PHDr. Nichols is a FERV Professor at the University of HoustonCollege of Optometry. Dr. Nichols has stock options inTearLab. She is a consultant for Alcon, Allergan, Bausch +Lomb and SarCode. She has received research supportfrom Alcon, Allergan, SarCode, TearLab and Vistakon.

John L. Schachet, ODDr. Schachet is president and CEO of Eyecare ConsultantsVision Source in Englewood, Colo. He is a consultant/advisor to Alcon and Tear Science. He has received research support from Alcon. He has lecturedand/or received honoraria from Alcon and CooperVision.

References1. Best N, Drury L, Wolffsohn JS. Predicting success with sili-

cone-hydrogel contact lenses in new wearers. Cont Lens Ante-rior Eye March 19, 2013; Epub ahead of print.

2. Situ P, Simpson TL, Jones LW, Fonn D. Effects of siliconehydrogel contact lens wear on ocular surface sensitivity to tac-tile, pneumatic mechanical, and chemical stimulation. InvestOphthalmol Vis Sci 2010;51(12):6111-6117.

3. Rumpakis J. New data on contact lens dropouts: an interna-tional perspective. Rev Optom 2010;147(1):37-42.

See product instructions for complete wear,care, and safety information


B Y J A S O N M I L L E R , O D , M B A , F A A O

Contact Lens Practice Pearls

time and energy from the doctorand staff. This may be especiallydifficult when your practice has afull schedule. You need a unifiedapproach to discussing daily disposable lenses, especially for patients who present with nocomplaints in their current contact lens prescription.

Break the IceIf you believe in the daily dis-

posable concept and a patient pre-sents with no complaints and justwants to renew his contact lensprescription, consider at least set-ting the stage for a daily disposablerefit. Use a simple introductionsuch as, “Your contact lenses areworking great, but you may want to consider trying daily disposablelenses in the future. They offer excellent vision and are a healthyoption, but with added conve-nience, because you can throw outthe lenses each night and use newlenses in the morning. There’s noneed to buy lens care solutions.” A patient may ask, “but how muchdo they cost?,” which leads rightinto our pricing strategies.

Pricing StrategiesProper pricing strategies help

set the stage for daily disposables.

You can even turn the price discussion into one easy sentence,“cost savings, manufacturer mail-in rebates and in-office instant rebates will counteract the pricedifference and may even save yousome money when compared toreusable lenses.” I usually go onto explain how the cost is virtuallya break-even when you considermanufacturer rebates and no needto buy care solutions. And thenthere’s the most important com-modity — your time in not hav-ing to care for contact lenses!

1. Remove pre-conceived obstacles!First, consider removing your obstacles.

Many eyecare professionals assume patientsdon’t want daily disposable contact lenses because of the presumed cost increase to thepatient. It’s important to understand thatwhatever the dollar difference, many patientsare willing to accept it when they recognizethe value of the product. Many of us use thesetechniques with regard to optical sales, butthey also apply when discussing daily dispos-able contact lenses:

Don’t avoid the issue of price: Talkabout the price up front.

Explain the value equation: Daily dis-posable contact lenses provide improved con-venience. Patients don’t have to worry aboutthe extra costs associated with other modali-ties, such as buying solutions. If they rip or

It’s easy to say patients will benefit from daily dis-posable contact lenses, but it’s more difficult togo out there on a daily basis and discuss this.Recommending and refitting everyone requires

tear a lens, they haven’t substantially increased their costs.2. Discuss the price after factoring inrebates and solution cost savings!

Many online stores will quote prices after rebates, cost savings and/or discounts. Apply-ing the same principal to daily disposable con-tact lenses, we could take these factors intothe price equation:

Try new pricing and promotionalstrategies: Consider discounting per box retail price for annual supply purchases. I callthat an In-Office Instant Rebate. The priceyielded on higher sales volume will offset anymargins lost on a per box purchase.

Make it easy for the patient to dobusiness with you: Offer free direct-ship for all daily disposable orders. Many patientswill take advantage of the large manufacturerrebates.

Develop a GoalTake a snapshot of where your

current daily disposable sales areas a starting point. Most distribu-tors or manufacturers can provideyour total daily disposable sales asa percent of overall contact lenssales. Use those numbers to take aunified approach to moving yournumbers in a specified direction.The daily disposable modality is agreat product to consider renew-ing your practice’s contact lensfocus. CLS

Setting the Stage for DailyDisposable Contact Lenses

Dr. Miller is in a partnership private practice inPowell, Ohio, and is an adjunct faculty memberfor The Ohio State University College of Op-tometry. He has received honoraria for writing,speaking, acting in an advisory capacity, or re-search from Alcon, Allergan, CooperVision, andVisioneering Technologies. You can reach himat [email protected].


B Y G A R Y G E R B E R , O D

The Business of Contact Lenses

Dr. Gerber is the president of the Power Prac-tice, a company offering proven and compre-hensive practice and profit building systems.You can reach him at www.PowerPractice.comand follow him on Twitter @PowerYourDream.

to cross the finish line wins therace too. Of course, the race andfinish line for an ECP doesn’t involve the waving of a checkeredflag. Instead, it means increasedprofits and a healthier, more vibrant practice.

Winning in PracticeBut what’s our equivalent of the

race and finish line? It awaits prac-titioners with the foresight, wis-dom and business acumen torealize the benefits of bringing“firsts” to their patients; beingknown in their communities as thego-to guy or gal for everythingnew in eye care. And the first we’retalking about here is new contactlens technology. As in sports, thefirst one wins. In this case, the firstECP to offer the latest technologyto his patients, and those patientswho benefit from the technology,are the winners.

Why Winning is ImportantIf you’re the first ECP in your

area to offer a new technologycontact lens, your patients aremore likely to perceive you asahead of the curve compared toothers. It’s just plain common sense

to think that those who offer new technology first are techno-logically ahead of those who do

not. This perception of being anexpert percolates down to all as-pects of your practice. “If they of-fer the latest contact lenses, theymust do everything else really welltoo.” You wouldn’t expect a car-diac surgeon who performs thelatest surgical procedure to offerleeches as an alternative therapy.An extreme example? Yes, but it

proves the point. Patients in of-fices offering new technologydon’t expect, and won’t receive,HEMA lenses. In fact, we oftendefine and judge our peers basedon their proclivity to embrace andespouse new technologies. If wedo it, don’t you think our patientswill, too? In other words, im-pressed patients will spread theword, and free word-of-mouthmarketing is the best kind.The other benefit to being the

first to offer new technology is aneconomic one. Early adopter pa-tients gravitate to early adopterECPs. As such, they aren’t de-terred by slightly higher prices.Offering patients the newest in

The first person to cross the finish line wins therace. That’s a truism in running, swimming, cy-cling and car racing. And, in my experience, it’s asafe bet that the first eyecare practitioner (ECP)

contact lens technology might notget you an Apple iPhone line out-side your office, but conceptually,the idea is the same. Satisfied pa-tients = long-term patients, andlong-term patients generate moreincome and loyalty over time.This is Economics 101 and it’sbeen demonstrated hundreds oftimes. We’ve heard stories of peo-ple who paid hundreds of dollarsfor calculators in the seventies, butwhat about the stories of thosewho SOLD those calculators?They enjoyed a nice economicride because they were among thefirst to offer “new technology.”

Check Your Opinion at the DoorA key point to winning and be-

ing first is that it is the patient,not the ECP, who ultimately de-cides if the race is even worth run-ning. It is the patient who willdetermine if the added benefits ofa new contact lens are worth theentrance fee to participate in therace. It is NOT and should not bethe ECP’s place to decide this forthe patient. Doing so will costyour practice thousands of dollars.Prejudging a patients’ desire toacquire and pay for new technolo-gy can be the costliest practice-building mistake you can make.

Your Trophy AwaitsThe race is yours to win or

lose. But to do either, you have toparticipate. And if you participateNOW, the odds of winning areastronomically high! CLS

Winning the Race

What’s our equivalent to the race and thefinish line?


B Y C H R I S T I N E W . S I N D T , O D , F A A O

Pediatric and Teen CL Care

Dr. Sindt is a clinical associate professor ofophthalmology and director of the contact lensservice at the University of Iowa Department ofOphthalmology and Visual Sciences. She is thepast chair of the AOA Cornea and Contact LensCouncil. She is a consultant or advisor to AlconVision Care and Vistakon and has received research funds from Alcon. You can reach herat [email protected].

their children and may worryabout the child’s level of respon-sibility. Doctors often feel morecomfortable fitting children indaily disposable lenses, too (Sindt,Riley 2011). With the simplicityof the daily disposable replace-ment system and the benefit ofenhanced compliance (Dumble-ton 2009), it’s no surprise thatchildren are prescribed the high-est proportion of daily disposablecontact lenses (Efron 2011).

Optimizing VisionMost common pediatric pre-

scriptions are available in dailydisposable lenses, and severalstudies have found that theselenses provide better vision com-pared to reusable daily wear softlenses, with fewer symptoms ofcloudy vision (Nason et al 1994,Solomon et al 1996, Fahmy et al2010). Furthermore, myopic chil-dren under 12 report better vision-related quality of life whenfit with contact lenses comparedto eyeglasses (Rah et al 2010).

Improving ComfortComfort is enhanced by plac-

ing a fresh lens on the eye eachday, thereby eliminating biofilmsthat may build up in a lens case

(Chalmers et al 2012). Lens deposits may lead to symptoms of dryness and discomfort. Dailydisposable hydrogel lens wearershave fewer toxic and hypersensi-tivity reactions (Radford et al2009) than reusable lenses, andthese lenses have been shown toimprove the signs and symptomsof tired, irritated eyes, blurred vi-sion, redness, discomfort, depositsand dryness (Fahmy et al 2010).Daily disposable lenses are

available in silicone hydrogel, amaterial that has been extensivelystudied and shown to minimizehypoxic signs, such as limbal hy-peremia, and improve comfort.Replacing the lens daily re-

duces the build-up of denaturedproteins and other antigens thataccumulate on the lens duringwear. In one study, some patientsreported they were able to dis-continue allergy medicationswhen using daily disposable con-tact lenses (Hayes et al 2003).

Better CompliancePoor patient compliance may

lead to adverse events, and poorcompliance with care regimens isrampant among contact lenswearers. But daily disposablelenses require only proper hand-

Daily disposable lenses offer a number of advan-tages for children, and parents often appreciatethe advantages of convenience and compliance.They also want the best visual performance for

washing prior to insertion and removal. It may be difficult forparents to monitor their child’scompliance, so reducing thenumber of steps to maintain com-pliance makes parents and doc-tors more confident that childrenwill be able to enjoy contact lenswear without problems.

Cost ComparisonChildren are more likely to en-

gage in part-time contact lenswear (Efron et al 2011), and dailydisposable lenses are less expensivewhen worn 1 to 4 days per weekcompared to reusable lenses. Theyequal the cost of reusable lenses at5 days per week of wear and areslightly more expensive whenworn full time (Efron et al, 2010).Parents appreciate having replace-ment lenses on hand in case chil-dren damage or tear lenses.Overall, many parents feel thebenefits of safety and complianceoutweigh any cost concerns.From comfort and conve-

nience to improved vision, dailydisposable lenses are a great vi-sion correction option for pedi-atric patients. CLS


Why Daily Disposable LensesMake Sense for Children


B Y W I L L I A M L . M I L L E R , O D , P H D , F A A O

Treatment Plan

Dr. Miller is an associate professor and chair ofthe Clinical Sciences Department at the Univer-sity of Houston College of Optometry. He is amember of the American Academy of Optome-try and the AOA. He is a consultant or advisorto Alcon and Vistakon and has received re-search funding from Alcon and CooperVisionand lecture or authorship honoraria from Alconand Bausch + Lomb. You can reach him [email protected].

anterior segment and contact lensconditions. In this column, I willsummarize what we know aboutcontact lens-related irritationbased on what we’ve learned fromthe DEWS Report and the MGDWorkshop. The DEWS reportcited contact lens discomfort anddryness as primary reasons whyour patients become less tolerantof contact lens wear (DEWS Report). Some of these patients are known (complainers) and someunknown (silent tolerators) to ourstaff and ourselves. The former arelikely to drop out of contact lenswear entirely. Between 50 and 75 percent of all patients complainof some form of ocular irritationwhile wearing contact lenses(DEWS Report). Dropout ratesfor contact lens wearers have beenreported to be between 12 and 28 percent, depending on the cri-teria used in the particular study(Schlanger, 1993; Weed et al,1993; Pritchard et al, 1999; Younget al, 2002; Richdale et al, 2007;Rumpakis, 2010; Dumbleton et al,2013). More troubling is that de-spite advances in lens materials,wetting agents and designs, notmuch has changed over severaldecades with regard to contact lenscomfort.

According to the 2007 DEWSReport, dry eye as defined by thereport is broadly defined as aque-ous (Sjogrens or non-Sjogrens) andevaporative (MGD). Contact lens-es are seen as extrinsic factors thataffect the tear film, causing evapo-rative effects. This may be the re-sult of a thinning of the pre-lenstear film or an insufficient wettingof the contact lens surface, both ofwhich affect tear film stability onthe anterior surface of the contactlens. Material properties may leadto wettability issues with additionalissues caused by lens deposition inthe form of denatured protein andlipids. This can be addressed usingadequate lens care regimen com-pliance, but also through the pre-scribing of daily disposable contactlenses. Although contact lensescause evaporative effects, they mayalso disturb aqueous productionthrough a sensory reflex blockmechanism. Higher water contactlenses have been associated withdryness, however this has not beena universally accepted truth andthus remains controversial withinthe field (DEWS Report).

Additional information aboutthe effects of contact lens on thetear film as they relate to the mei-bomian gland is described in the

Contact lens-related discomfort, especially late inthe day or after prolonged near activities, is asignificant problem for many of our patients. Mycolumn usually focuses on the frank treatment of

MGD workshop report. (Knop et al, 2011) As reported, because ofits action on the meibomian gland,estrogen treatment can lead to tearfilm instability and reduced contactlens tolerance (Knop et al, 2011).Contact lenses may also cause ep-ithelial keratinization as well asmeibomian gland orifice obstruc-tion that can further complicatesuccessful wear. It has also beennoted that contact lens wearershave a high meibomian gland dropout rate that may be related to thekeratinization cycle, however theprecise mechanism is not known.This dropout rate mimics what isfound in the normal aging process.A critical reading of two well regarded published reviews on ocular dryness and meibomiangland dysfunction may help in addressing many issues that affectcontact lens patients. Further management in the form of topicaldrops, contact lens care systemsand novel contact lens tech-nologies may further help more patients stay comfortable through-out the day, reduce intolerance andlimit drop outs.


Contact Lens Discomfort: CanPast Workshops Provide Insight?


END-OF-DAY

9.2 OUT OF 10

COMFORT

Time of0.0%

50%

100%


100% 100%

Prior to0.0%

50%

Insertion Time of

PER

CEN

T O

F LU

BR

ICIT

Y F

AC

TOR

Removal

100%

~100%33% >80%>80%

Let your patients experience the DAILIES TOTAL1® contact lens difference today.


Lens maintains 100% of its initial lubricity even after a day of wear1

100% LUBRICITY MAINTAINED

Ultrasoft, hydrophilic surface gel approaches 100% water at the outermost surface6 for exceptional lubricity

LASTING LUBRICITY



The First and Only Water Gradient Contact Lens


THIS IS WHY lasting lubricity means lasting comfort.DAILIES TOTAL1® Water Gradient Contact Lenses maintain 100% of their lubricity after a day of wear.1 And because lubricity is highly predictive of contact lens comfort, lasting lubricity means lasting comfort.2, 3, 4

PERFORMANCE DRIVEN BY SCIENCE™

1. Alcon data on fi le, 2011.2. Brennan N. Contact lens-based correlates of soft lens wearing comfort. Optom Vis Sci. 2009;86:E-abstract 90957.3. Coles CML, Brennan NA. Coeffi cient of friction and soft contact lens comfort. American Academy of Optometry. 2012;E-abstract 125603.4. Kern JR, Rappon JM, Bauman E, Vaughn B. Assessment of the relationship between contact lens coeffi cient of friction and subject lens comfort. ARVO 2013;E-abstract 494, B0131.5. Thekveli S, Qiu Y, Kapoor Y, Kumi A, Liang W, Pruitt J. Structure-property relationship of delefi lcon A lenses. Cont Lens Anterior Eye. 2012;35(suppl 1):e14.6. Angelini TE, Nixon RM, Dunn AC, et al. Viscoelasticity and mesh-size at the surface of hydrogels characterized with microrheology. ARVO 2013;E-abstract 500, B0137.

See product instructions for complete wear, care, and safety information. © 2013 Novartis 6/13 DAL13224JAD

>80%33%>80%

WATER CONTENT (%)

Contact Lens Sp

ectrum 13th SE

82411 DAL13224JAD CLS.indd 1 5/31/13 10:18 AM

END-OF-DAY

9.2 OUT OF 10

COMFORT

Time of0.0%

50%

100%


100% 100%

9.2 OUT OF 10

COMFORT

Time of0.0%

50%

100%


100% 100%

PERFORMANCE DRIVEN BY SCIENCETM

THIS IS WHY contact lenses have reached a new era in comfort.DAILIES TOTAL1® Water Gradient Contact Lenses feature an increase from 33% to over 80% water content from core to surface* for the highest oxygen transmissibility, and lasting lubricity for exceptional end-of-day comfort.1, 2, 3

The First And Only Water Gradient Contact Lens

Let your customers experience the DAILIES TOTAL1® contact lens difference today.


>80%33%>80%

WATER CONTENT (%)

*In vitro measurement of unworn lenses.1. Based on the ratio of lens oxygen transmissibilities among daily disposable contact lenses. Alcon data on fi le, 2010.2. Based on critical coeffi cient of friction measured by inclined plate method; signifi cance demonstrated at the 0.05 level. Alcon data on fi le, 2011.3. In a randomized, subject-masked clinical study, n=40. Alcon data on fi le, 2011.4. Angelini TE, Nixon RM, Dunn AC, et al. Viscoelasticity and mesh-size at the surface of hydrogels characterized with microrheology. ARVO 2013;E-abstract 500, B0137.

See product instructions for complete wear, care and safety information. © 2013 Novartis 04/13 DAL13097JAD

Ultrasoft, hydrophilic surface gel approaches 100% water at the outermost surface for exceptional lubricity4

LASTING LUBRICITY




Lasting lubricity for exceptional comfort from beginning to end of day3

OUTSTANDING COMFORT

~100%33% >80%>80%



contact lens spectrum lens spectrum a proud supporter of body stock only group publisher, optometric...

Documents