Subjective comfort with three silicone hydrogel daily disposables in symptomatic contact lens...

Comfort Response of Three Silicone HydrogelDaily Disposable Contact Lenses

Jalaiah Varikooty*, Nancy Keir†, Doris Richter‡, Lyndon W. Jones§, Craig Woods||, and Desmond Fonn**

ABSTRACTPurpose. To evaluate subjective ocular comfort across the day with three silicone hydrogel daily disposables (SHDDs) ina group of adapted lens wearers.Methods. Masked subjects (asymptomatic or symptomatic of end-of-day (EOD) dryness with habitual lenses) wore threeSHDDs: DAILIES TOTAL1 (DT1), Clariti 1day (C1D), or 1-DAYACUVUE TRUEYE (AVTE), each for 3 days. On day 2, wearingtime (WT) and comfort ratings after insertion, at 4, 8, and 12 hours, and at EODwere recorded. Because not all subjects worelenses for 12 hours, comfort was analyzed across the day (up to 8 hours, 8 to 12 hours), and a new variable (‘‘cumulativecomfort’’ [CC]) was calculated for EOD.Results. One hundred four subjects completed the study (51 asymptomatic, 53 symptomatic). The two groups haddifferent WTs (mean WT, 14.0 and 12.7 hours, respectively; p G 0.001). Ocular comfort was rated higher in the asymp-tomatic group throughout the day (p G 0.001). One hundred four subjects wore all three SHDDs for at least 8 hours, whereas74 (45 asymptomatic, 29 symptomatic) subjects wore them for 12 hours or longer. Comfort ratings were higher with DT1(least square means [LSM] = 91.0) than with C1D (LSM = 86.5; p G 0.001) and AVTE (LSM = 87.7; p = 0.011) for the first8 hours and lower with C1D compared with DT1 (p = 0.012) from 8 to 12 hours. Mean EOD (T SD) comfort with the C1Dlens was 72 T 21, lower than both DT1 (mean, 79 T 17; p = 0.001) and AVTE (mean, 78 T 21; p = 0.010). Mean CCwas higherin the asymptomatic group (mean, 1261 T 59) compared with that in the symptomatic group (mean, 1009 T 58; p G 0.001)and higher for DT1 (mean, 1184 T 258) than C1D (mean, 1094 T 318; p = 0.002) and AVTE (mean, 1122 T 297; p = 0.046).Conclusions. All three SHDDs had average WTs of 12 hours or longer for 1 day. Comfort during the first 12 hours washighest with DT1 (similar to AVTE between 8 and 12 hours) and lowest with C1D. End-of-day comfort was lowest with C1D,and CC was highest for DT1. Cumulative comfort may be a valuable new metric to assess ocular comfort during the day.(Optom Vis Sci 2013;90:945Y953)

Key Words: contact lens, silicone hydrogels, daily disposable, comfort

Contact lens patients complain of ocular dryness and dis-comfort at the end of the day (EOD) with their contactlenses, despite the development of new contact lens

products during the past decade to mitigate these symptoms.1,2

Discomfort and dryness associated with lens wear continue to bean important issue, as reflected by the high annualized number ofcontact lens dropouts, with discomfort consistently being the

primary driver.2Y5 Efforts to address symptoms of ocular dis-comfort and dryness that worsen toward the EOD4,6 have in-cluded the development of contact lens materials that exhibit lowlevels of on-eye dehydration,7 lens materials and blister-pack so-lutions that incorporate components to enhance wettability, suchas polyvinyl alcohol8 and polyvinyl pyrrolidone,9 disinfecting so-lutions incorporating various surfactants and wetting agents,10,11

and rewetting drops and tear substitutes containing hydrophilicpolymers and other substances such as hyaluronic acid.12

The high level of convenience, increased compliance with re-placement frequency,13,14 reduced deposition, and an absence oflens care and the associated solution-induced corneal staining,15,16

along with their reduced number of clinical complications,17,18 aresome of the possible reasons resulting in an ever-increasing num-ber of patients being fitted with daily disposable contact lenses.19

Until recently, however, daily disposable contact lenses were only

1040-5488/13/9009-0945/0 VOL. 90, NO. 9, PP. 945Y953

OPTOMETRY AND VISION SCIENCE

Copyright * 2013 American Academy of Optometry

ORIGINAL ARTICLE

Optometry and Vision Science, Vol. 90, No. 9, September 2013

*MBBS, MSc†OD, PhD, FAAO‡OD, MASc§PhD, FCOptom, FAAO||PhD, MCOptom, FAAO

**MOptom, FAAO

Centre for Contact Lens Research, School of Optometry and Vision Science,

University of Waterloo, Waterloo, Ontario, Canada (JV, NK, DR, LWJ, DF); and

School of Medicine (Optometry), Deakin University, Waurn Ponds, Victoria,

Australia (CW).

Copyright © American Academy of Optometry. Unauthorized reproduction of this article is prohibited.

available in nonsilicone hydrogel materials, lacking the physiolog-ical benefits of higher levels of oxygen transmissibility provided bysilicone hydrogel materials. This situation has changed throughthe introduction of the silicone hydrogel daily disposable (SHDD)lens materials: narafilcon A and B (1-DAY ACUVUE TRUEYE[AVTE]; Johnson & Johnson Vision Care, Inc.),20 filcon II 3(Clariti 1day [C1D]; Sauflon Pharmaceuticals Ltd.),21 and delefilconA (DAILIES TOTAL1 [DT1]; Alcon Laboratories, Inc.).19,22

Silicone hydrogel daily disposables have been recently intro-duced, and studies reporting the ocular comfort experienced withthe use of these lenses are relatively sparse compared with SHfrequent replacement lenses.16,17,21,23,24 Therefore, the objectiveof this study was to measure ocular comfort for 1 day in asymp-tomatic and symptomatic subjects who each wore three differentSHDD lenses.

METHODS

The study was conducted as a prospective, randomized, bilat-eral, crossover trial. Complete masking of the investigators was notpossible because they may have recognized lens design features ormarkings while evaluating lenses on-eye. Subjects were completelymasked, however, by overlabeling the lens blister packs, andcurrent wearers of SHDD lenses were excluded from the study,which meant that none of the subjects had previous experiencewith any of the study lenses. In addition, the identity of thesponsor (Alcon Laboratories, Inc.) was not disclosed until the endof the study.

The eligibility of subjects was determined through a screen-ing assessment, which included biomicroscopy, a lens-fittingassessment, and a questionnaire on the frequency (0 = never,4 = constantly) and intensity (0 = never have it, 5 = very intense)of late day dryness, modeled after the Contact Lens Dry EyeQuestionnaire.6 Subjects were adapted soft contact lens wearersand were free of ocular and/or systemic disease that could impactcontact lens wear. In addition, subjects needed to achieve aclinically acceptable fit with each of the study lenses to be eligible.Ethics clearance was obtained through the Office of Research

Ethics at the University of Waterloo, and each subject underwentan informed consent process before entering the study. All subjectswere treated in accordance with the tenets of the Declaration ofHelsinki, and the study was conducted according to Good ClinicalPractice Guidelines.

Once eligibility was confirmed, subjects were assigned to eitheran asymptomatic or symptomatic group on the basis of their re-sponse to the frequency and intensity of late day dryness duringthe past week. The grouping assignment followed the classifica-tion proposed by Young et al.25

Fig. 1 describes the study design, and lens details are providedin Table 1. Subjects wore all three study lenses, with the order oflens wear being randomized. There was at least a 1-day breakbetween wearing of each study lens, when subjects could choose towear either their spectacles or habitual contact lenses. Study lenseswere dispensed before each study phase according to the subject’srandomization and worn for three consecutive days of daily dis-posable wear. Subjects inserted the study lenses directly from theblister pack and were advised to refrain from using any artificialtears during the study. Assessments were made at the Centrefor Contact Lens Research on day 1, in the morning when lenseswere dispensed, and after 8 hours of wear, and also on day 3, after8 hours of wear. On day 2, there were no clinical assessments, sosubjects had a full day of lens wear, uninterrupted by in-officeassessments, during which they rated comfort across the entireday. A post hoc analysis of the day 2 at-home ratings is reported inthis article.

At-home ratings on day 2 were recorded promptly after lensinsertion and then every 4 hours and immediately before lensremoval. Ratings were recorded on paper and brought to theappointment at the following visit. Insertion and removal timeswere recorded, and comfort was rated using a 0 (‘‘very poor’’) to100 (‘‘excellent’’) visual analog scale. Compliance was not mon-itored; however, clear instructions were provided and subjectswere asked to report the time each rating was recorded. In-structions also advised subjects to wear the study lenses for as longas they were able and to remove them when they normally wouldor when they became uncomfortable and always before overnight

FIGURE 1.Study design and lenses.

946 Comfort and Hydrogel Daily Disposable Contact LensesVVarikooty et al.



sleep. The end of wear comfort reported just before lens removalis often referred to as ‘‘end-of-day comfort’’ in the publishedliterature26,27, and for consistency, we will also refer to the end ofwear as EOD.

As the lens removal time occurred at different times for subjectswith each of the study lenses, post hoc analysis was done and anew variable termed ‘‘cumulative comfort’’ (CC) was developedto incorporate the wearing time (WT) into the interpretation ofEOD comfort. The CC score was calculated by summing thecomfort scores for each hour of lens wear. This was estimatedusing the ratings that were completed every 4 hours until theremoval time was reached and by assuming that the comfortrating for the hours before the rating time point were equivalent.The EOD rating was used for the remaining hours. As an example,if someone was only able to wear his or her lenses for 10 hours,the CC score would be 4*VAS@4hrs + 4*VAS@8hrs + 2*VAS@EOD, where VAS stands for ‘‘visual analog scale score.’’ Theresulting score can be roughly interpreted by considering thatevery 100 units represent the equivalent of 1 hour of ‘‘perfectcomfort.’’ However, some care needs to be taken with respectto this interpretation because it is possible to arrive at the samescore in different scenarios; for instance, 2 hours of lens wear witha comfort rating of 50 would also yield a CC score of 100 units.

Data were analyzed using Statistica 10,28 with the goal of de-termining whether there were any differences between lensesor symptomatic groups with respect to comfort across the day.Analysis of variance and Tukey post hoc testing were conducted forcomfort ratings with the following factors: group (asymptomaticand symptomatic), lens (three levels within subject), and timepoint (including all time points with complete data except EOD).Because the comfort ratings for EOD were complicated by thefact that these ratings occurred at different times of the daywith different lenses, EOD and CC were analyzed using post hocmethods. The EOD comfort ratings and CC scores were analyzedusing analysis of variance and Tukey post hoc testing, with groupand lens as factors. The least square means (LSMs) are reported.The statistical significance level was set at p G 0.05, with no

adjustments for multiplicity. Descriptive statistics have alsobeen reported.

RESULTS

A total of 119 subjects were enrolled in the study. Fifteensubjects discontinued from the study because of either personalinconvenience or nonYstudy-related reasons. Therefore, 104subjects completed the study (75 female, 29 male) and were in-cluded in the analysis.

The mean age of the 104 subjects was 27 T 9 years (median,23 years; ranging from 17 to 51 years). There were 51 subjects inthe asymptomatic group and 53 subjects in the symptomaticgroup. Twenty-three percent of subjects typically wore theirhabitual lenses for 14 hours or more (eight in the symptomaticgroup and 16 in asymptomatic group). The type of habitual lensand habitual wearing modality of the subjects are describedin Tables 2 and 3.

The mean comfort ratings (TSD) at each time point on day 2of the study are summarized in Table 4.

The EOD comfort ratings occurred at the end of the WT foreach subject, not at a specific time point. The distribution ofWTs ranged from 9 to 19 hours in the asymptomatic group andfrom 7 to 18 hours in the symptomatic group, as shown in Fig. 2.The mean WT, including all three lens materials, was 14.0 hours

TABLE 1.

Lens parameters

Lens properties

Manufacturer/supplier Alcon Laboratories, Inc. Sauflon Johnson & Johnson Vision CareLens name DAILIES TOTAL1 Clariti 1Day 1-DAY ACUVUE TruEyeMaterial delefilcon A filcon II 3 narafilcon AFDA contact lens material group Group I Group II* Group IWater content 33% in the core of the lens and 980%

at the surface†56% 46%

Dk/t value (j3.00 D) 156 86 118Diameter, mm 14.1 14.1 14.2BCOR, mm 8.5 8.6 8.5, 9.0Modulus, MPa 0.7 (lens core) 0.5 0.66Power (DSph) (0.25 steps) j1.00 to j6.00 j1.00 to j6.00 j1.00 to j6.00Stated central thickness, mm @ j3.00 D 0.090 0.070 0.085

*Group II designation assumed based onmaterial properties (nonionic, high water polymer) and not on FDA clearance or approval. Nopublicly available USAN name.

†As reported by Alcon Laboratories, Inc.

TABLE 2.

Summary of habitual lens types worn

Percentage of subjects

Habitual lensDaily

disposablesFrequent

replacement

Hydrogel lenses 25 18Silicone hydrogel lenses 0 57

Comfort and Hydrogel Daily Disposable Contact LensesVVarikooty et al. 947



for the asymptomatic group and 12.7 hours for the symptomaticgroup; this difference was statistically significant (p G 0.001).

The First 8 Hours

Fig. 3 shows the comfort ratings for time points up to 8 hoursfor all 104 subjects (51 asymptomatic, 53 symptomatic). WhenEOD occurred between 7 and 8 hours, these data were includedas 8-hour data.

On average, the comfort ratings were higher in the asymp-tomatic group (LSM = 92.0) than in the symptomatic group(LSM = 85; p G 0.001). In the symptomatic group for all lensescombined, the mean comfort rating at 8 hours was lower thanat insertion and at 4 hours (both p G 0.001). The overall meancomfort rating with the DT1 lens (LSM = 91.0) was higher thanthat with C1D (LSM = 86.5; p G 0.001) and AVTE (LSM = 87.7;p = 0.011) lenses; however, there was no statistically significantdifference between C1D and AVTE (p 9 0.05) lenses.

Between 8 and 12 Hours

Seventy-four subjects (45 asymptomatic, 29 symptomatic)wore all three lens materials for at least 12 hours. The change incomfort ratings from 8 to 12 hours is shown in Fig. 4 for thesesubjects. The remaining 30 subjects did not reach 12 hours of lenswear for one or more of the lens materials, and the number of

subjects removing their lens before 12 hours is shown in Fig. 5.For all lenses combined, comfort ratings were lower in the symp-tomatic group (LSM = 80.0) compared with that in the asymp-tomatic group (LSM = 90.0; p G 0.01), and there was a significantdifference between comfort ratings at 8 hours as compared with12 hours (p G 0.01). For both groups combined, ocular comfortwas rated lower with the C1D lens (LSM = 84.0) compared withthe DT1 lens (LSM = 88.0; p = 0.012). There was no statisticallysignificant difference in comfort rated between the DT1 lens andthe AVTE lens (LSM = 85.0; p 9 0.05).

EOD Comfort and CC Score

The mean EOD comfort ratings (TSD) for all 104 subjects areshown in Table 4. For all lenses combined, the EOD comfortratings (mean T 95% confidence interval) were lower in the symp-tomatic group (69 T 4) compared with those in the asymptomaticgroup (84 T 4; p G 0.001). Overall, the mean EOD comfortrating for the C1D lens (72 T 4) was lower than those for boththe DT1 (79 T 3; p = 0.001) and AVTE (78 T 4; p = 0.010) lenses.There was no statistically significant difference in EOD comfortbetween the DT1 and AVTE lenses (p 9 0.05).

In studies where WTs or reasons for lens removal are notspecified, EOD comfort alone may not be an appropriate metricfor assessing lens performance in relation to ocular comfort. In thisstudy, for example, although the mean EOD comfort was lower

TABLE 3.

Percent of participants for each habitual lens brand

Habitual lens brand % Replacement schedule Material

ACUVUE OASYS with HYDRACLEAR PLUS 30 2 weeks Silicone hydrogelAIR OPTIX NIGHT & DAYAQUA 15 1 month Silicone hydrogelACUVUE ADVANCE with HYDRACLEAR 6 2 weeks Silicone hydrogelFocus NIGHT & DAY 3 1 month Silicone hydrogelPureVision 3 1 month Silicone hydrogelFocus DAILIES 7 DD Hydrogel1-DAY ACUVUE MOIST 5 DD HydrogelProclear 1 Day 5 DD HydrogelACUVUE 2 4 2 weeks Hydrogelencore100 3 1 month HydrogelFreshLook COLORBLENDS 3 2 weeks HydrogelSofLens daily disposable 2 DD HydrogelOther brands 14 (all 1% or less for each lens brand) DD, 2 weeks and 1 month All Hydrogel

TABLE 4.

Ratings of comfort at insertion, at 4 hours, 8 hours, and 12 hours, and at EOD (Day 2)

Mean T SD

Lens Insertion 4 h 8 h 12 h EOD

Asymptomatic group,n = 51 except at 12 h

DAILIES TOTAL 1 93 T 9 95 T 9 93 T 10 89 T 14, n = 49 84 T 16Clariti 1day 91 T 12 93 T 10 90 T 12 85 T 16, n = 48 81 T 18

1-DAYACUVUE TRUEYE 89 T 18 93 T 10 91 T 11 88 T 15, n = 47 86 T 15

Symptomatic group,n = 53 except at 12 h

DAILIES TOTAL1 91 T 10 90 T 9 84 T 12 79 T 16, n = 45 74 T 16Clariti 1day 88 T 12 83 T 12 75 T 19 71 T 18, n = 40 63 T 20

1-DAYACUVUE TRUEYE 89 T 12 85 T 16 79 T 19 76 T 17, n = 38 70 T 22




when subjects wore the C1D lens than that when subjects wore theAVTE, arithmetically, more subjects wore the C1D lens for atleast 12 hours. This raises the interesting question that if subjectswear their lenses longer, but end up with a lower EOD comfortscore, does this mean the performance of this lens was worse than

a lens that had a higher EOD comfort score but was removedearlier? Given that subjects in this study were permitted to removelenses before the 12-hour time point, early removal of a selectlens material (or materials) might in fact be an indicator of dis-comfort. Although the reason for lens removal was not captured

FIGURE 2.Wearing times for the asymptomatic and symptomatic groups.

FIGURE 3.Mean comfort ratings for first 8 hours (T95% confidence interval).




in this study, each participant wore all three SHDDs; therefore,the overall typical behavior (i.e., routinely removing before bedduring a standard work week) should have been similar for eachlens material or, alternatively, different behaviors would haveresulted in random effects because the order of lenses were

randomized. As a result of the differences in WTs, post hoc CCscores were calculated, and results are shown in Fig. 6. Themean CC score was lower in the symptomatic group (1009 T 58)compared with that in the asymptomatic group (1261 T 59;p G 0.001) and was lower for both the C1D (1094 T 318; p = 0.002)

FIGURE 4.Mean comfort ratings between 8 and 12 hours for subjects who wore all lenses at least 12 hours (T95% confidence interval); asymptomatic group, n = 45;symptomatic group, n = 29.

FIGURE 5.Number of subjects removing lenses before 12 hours.




and AVTE (1122 T 58; p = 0.046) lenses than for the DT1 lens(mean, 1184 T 50). The difference in CC between the AVTE andC1D lenses was not statistically significant (p 9 0.05).

DISCUSSION

Silicone hydrogel daily disposable contact lenses were intro-duced in 2009, and relatively few studies have been published to-date regarding their performance,16 particularly regarding ocularcomfort toward the end of the lens-wearing period. This studyreports ocular comfort with three SHDD lens materials inadapted lens wearers who are asymptomatic and symptomaticfor EOD dryness with their habitual lenses. The results indicatethat subjects experience good ocular comfort with all three lenses,with the lowest mean comfort rating being 71 units (out of 100)at 12 hours in the symptomatic group. The difference in meancomfort between the three lenses was about three to four points ona 0 to 100 scale, and the DT1 was rated slightly higher thanthe other two study lenses. Although the clinical relevance of thisslight difference could be debated,29 the optimal methods for de-riving clinical significance for ocular comfort remain to beproperly established.

However, consistent with other soft lens studies,4,30,31 all threeSHDD lenses were associated with a decline in ocular comfortacross the day. The comfort ratings at 12 hours may be somewhatbiased because ratings were not reported by 30 participants whodid not wear lenses for this length of time. If these participantswere required to wear lenses for 12 hours or more, it is possiblethat the 12-hour comfort rating with all 104 subjects might havebeen lower. Although not recorded in this study, the reason for lensremoval would have been useful, and it would have been interestingto know whether any of the subjects who were originally classified as

symptomatic with their habitual contact lenses would have beenclassified as marginally symptomatic or asymptomatic after wear-ing any of the SHDDs. Ideally, future studies would include thisinformation.

In addition to differences in ocular comfort between the symp-tomatic and asymptomatic groups, which were not unexpected,there were also differences in WT. A greater number of subjects inthe asymptomatic group wore their lenses for 12 hours or morecompared with the symptomatic group. This may indicate that thebehavior of subjects with respect to their WT is dependent on thecomfort of the lens. ‘‘End-of-day comfort’’ is typically defined asthe comfort experienced just before lens removal, which is relatedto the total WT. Clinical trials reporting contact lensYrelatedsymptoms of comfort and dryness have mainly focused on meanand overall symptoms and report the mean WT, which has typi-cally varied between 12 and 16 hours.6,8,32,33 However, these re-ports do not specifically assess the impact of WT on overall orEOD ocular comfort. When WT was taken into consideration inthis study using post hoc analysis to provide a CC score, the comfortwas rated significantly higher for longer periods with the DT1 lenscompared with those for both the C1D and AVTE. Althoughthere may be different approaches to account for the impact of WTon ocular comfort, we feel that this is an interesting new comfortparameter that provides a better understanding of changes in ocularcomfort at the EOD and is a valuable way of comparing the relativeperformance of lenses across the day. In future studies, additionalinformation collected at EOD, such as the reason for lens removal,may also aid in the interpretation of EOD and CC.

Many factors can influence ocular comfort. Clinical findingsassociated with the three SHDDs investigated (i.e., visual acuity,lens wettability, lens deposition, and biomicroscopy) are the subject ofanother manuscript under preparation; however, nonYlens-related

FIGURE 6.Mean cumulative comfort for the asymptomatic and symptomatic groups (T95% confidence interval).




factors such as the environment, ocular health, and dry eye and lens-related factors such as material properties, subtle differences in lensdesign, and lens parameters may have all played a role. Although allthree lenses are manufactured from siloxane-based materials, each lenshas its own unique features. The AVTE material is embedded with amoisturizing and wetting agent, polyvinyl pyrrolidone, through aproprietary Hydraclear 1 technology to improve moisture retentionand lubricity of the lens without any additional surface coating ortreatment.22 The C1D lens manufacturing process includes a pro-prietary AquaGen technology intended to enhance the wettability ofthe lens material,21 and the DT1 lens is manufactured through aproprietary LightStream process and has a unique water contentgradient that varies from 33% in the core of the lens to more than 80%at the lens surface22 to provide increased surface lubricity. In a recentin vitro study comparing all three of these lenses, DT1 exhibited alower amount of in vitro bulk dehydration compared with those forAVTE and C1D34; however, to our knowledge, there have been noother published reports comparing these three lenses.

In summary, the three SHDD lenses investigated in this studyresulted in reasonably high levels of ocular comfort and longaverage WTs (Q12 hours) in adapted lens wearers, approximately50% of whom were symptomatic with their habitual non-SHDDlenses. Combined with the high oxygen transmissibility ofsilicone hydrogel materials and the convenience and other benefitsof a daily disposable modality, SHDDs are a valuable option forpractitioners to consider for their patients. Generally, comfortduring the first 12 hours was highest with the DT1 lens (similar tothe AVTE lens between 8 and 12 hours) and was lowest withthe C1D lens during 1 day of lens wear. End-of-day comfort waslowest with the C1D lens, and CC was highest for the DT1 lens.Further studies are necessary to determine whether these findingscontinue to hold up after longer periods of wear.

ACKNOWLEDGMENTS

Financial support for this study was provided by Alcon Laboratories, Inc.Received December 10, 2012; accepted May 6, 2013.

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Jalaiah VarikootyCentre for Contact Lens Research University of Waterloo 200

University Ave West WaterlooOntario Canada N2L 3G1

e-mail: [email protected]




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