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RESEARCH PAPER

A comparison of spectacle and contact lens wearing times in the ACHIEVE studya Clin Exp Optom 2010; 93: 3: 157–163 Lisa A Jones-Jordan* PhD Monica Chitkara† OD Bradley Coffey§ OD John Mark Jackson储 MS OD Ruth E Manny¶ OD PhD Marjorie J Rah** OD PhD Jeffrey J Walline* OD PhD * Ohio State University College of Optometry, Columbus, Ohio, USA † Columbus, Ohio, USA § Pacific University College of Optometry, Forest Grove, Oregon, USA 储 Southern College of Optometry, Memphis, Tennessee, USA ¶ University of Houston College of Optometry, Houston, Texas, USA ** Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA E-mail: [email protected]

Submitted: 4 December 2009 Revised: 4 February 2010 Accepted for publication: 9 February 2010

DOI:10.1111/j.1444-0938.2010.00480.x Purpose: The aim was to compare vision correction wearing time between myopic children and teenagers in a clinical trial of contact lenses and spectacles. Methods: Parents of subjects in the Adolescent and Child Health Initiative for Vision Empowerment (ACHIEVE) study provided wearing times for spectacle and contact lens wear. Hours wearing primary correction and total correction were compared between the two treatment groups. Other factors hypothesised to be associated with wearing time were analysed. Results: The average wearing time of the primary correction differed significantly with the wearing time for the spectacles group being 91.5 hours per week compared to 80.3 hours per week for the contact lens wearers (p < 0.0001). Total correction time was slightly higher for the contact lens wearers, 97.5 hours per week, after accounting for time wearing spectacles. Higher refractive error was strongly related to longer wearing times (p < 0.0002). Age and treatment group were associated with wearing time (p = 0.005). Young contact lens wearers wore their lenses less than young spectacle wearers and older contact lens wearers. Low scores on an appearance quality-of-life scale were associated with longer wearing time in spectacle wearers compared to the low- and high-scoring contact lens wearers. Gender, spectacle satisfaction and activities were not related to wearing time. Conclusions: While contact lens wearers, on average, wear their contact lenses less than spectacle wearers, they spend roughly the same amount of time wearing a refractive correction. Higher refractive error resulted in longer wearing times for both spectacle and contact lens wearers. Younger contact lens wearers wore their contact lenses for shorter periods than the spectacle wearers, but still wore them, on average, 74.4 hours per week (about 10 hours per day), suggesting that contact lenses are a viable alternative mode of correction for children.

Key words: clinical trial, contact lenses, glasses, paediatrics, spectacles, wearing time

The Adolescent and Child Health Initiative to Encourage Vision Empowerment a. These data were presented at the American Academy of Optometry meeting 2009

(ACHIEVE) study was designed to investigate the effects of contact lens wear on the self-perception of children who needed to wear spectacles to correct myopia.1 The ACHIEVE study used the ‘Self-Perception

© 2010 The Authors Journal compilation © 2010 Optometrists Association Australia

Profile for Children’ (SPPC) to measure a child’s feelings about general self-worth as well as other subscales.2 In addition to the SPPC, subjects completed a quality-of-life questionnaire (paediatric refractive error Clinical and Experimental Optometry 93.3 May 2010

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Comparison of spectacle and contact lens wearing times Jones-Jordan, Chitkara, Coffey, Jackson, Manny, Rah and Walline

profile [PREP]) specific to spectacles or contact lenses and a questionnaire about spectacle satisfaction (spectacle satisfaction survey); and a parent completed a survey detailing the amount of time the subjects wore their refractive error correction. Recent studies have shown children to be successful in contact lens wear across different contact lens modalities. Soft contact lenses,3–6 rigid gas permeable lenses (RGPs)6,7 and corneal reshaping lenses8,9 have all been worn successfully. With increasing numbers of children wearing contact lenses, information about how often they can be expected to wear their lenses in comparison to spectacles may help practitioners understand that contact lens wear provides continuous correction throughout the day but the lenses may not be worn as often. An underlying assumption when prescribing lens wear for children may be that contact lenses function in the same manner and for the same daily duration as spectacles. In addition, there may be differences in wearing time across modalities, such as age and gender. Determining whether contact lens and spectacle wearing times differ and assessing whether the amount of time that children wear their contact lenses encompasses the majority of the day can tell more about how the contact lenses are used by young myopes and may help in prescribing their correction. The objective of this analysis was to compare the amount of time subjects wore their assigned vision correction over the course of a week and to determine whether the wearing times between the spectacle and contact lens groups differed. Additional subgroups (age, gender et cetera) are examined as well. METHODS The ACHIEVE study had five participating US clinical sites. Consecutive subjects who met entry criteria were recruited from volunteers at optometric institutions in Boston, Massachusetts; Columbus, Ohio; Forest Grove, Oregon; Houston, Texas; and Memphis, Tennessee (Appendix). The protocols were approved by each Clinical and Experimental Optometry 93.3 May 2010

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clinical site’s Institutional Review Board and adhered to the tenets of the Declaration of Helsinki. Parents of all subjects signed parental consent forms and subjects signed informed assent forms. Details of the eligibility criteria and methods are available elsewhere1 but are described here briefly. The subjects were between eight and 11 years old, inclusive, at the baseline examination. They had between -1.00 D and -6.00 D myopia and less than 1.00 D of astigmatism, measured by cycloplegic autorefraction. They had 6/6 or better visual acuity at distance in both eyes and had not worn contact lenses within the past month. Subjects had healthy eyes that were suitable for contact lens wear. Subjects were assigned randomly to wear spectacles or contact lenses for three years. Subjects who wore spectacles received these at no or reduced cost and they were given vouchers for a free threeyear supply of contact lens materials at the completion of their three-year visit. Subjects who were assigned to wear contact lenses were fitted with either 1-DAY ACUVUE or ACUVUE 2 (Vistakon; Jacksonville, FL, USA) contact lenses. They also received free contact lens solutions as needed and no- or reduced-cost spectacles for back-up. The amount of time a child spent wearing the refractive correction was recorded by the parent at each visit. The form was introduced at the one-year visit and was completed at every visit after that, which occurred at six-month intervals through to the end of the study at three years. The form had questions about the time the subject got up in the morning and the time the subject went to bed in the evening. There was also a question that read as follows: ‘On average, while your child is awake, how many hours per day does he or she wear: glasses; contact lenses; no correction.’ From this, hours per week were calculated by multiplying by seven days. Correction was assessed by comparing treatment groups, that is, the amount of time those randomised to each group wore their assigned correction. To evaluate overall correction time, the time the spectacle wear group wore their spec-

tacles was compared to the time the contact lens group spent wearing contact lenses plus spectacles over all visits. Subjects who were non-compliant with their treatment assignment and crossed-over were analysed using the amount of wearing time in their assigned group. Subjects in the ACHIEVE study completed several additional questionnaires.1 The ‘spectacle satisfaction survey’ was designed to measure how a subject’s spectacles affected their daily life and was completed only at baseline. The hypothesis was that children with low spectacle satisfaction might wear their contact lenses longer than those children who were satisfied with their spectacles. The paediatric refractive error profile was completed at each visit was and assessed a subject’s vision-related functioning and quality of life. There are nine scales on the PREP addressing many areas including appearance, activities, scholastics and peer relationships. It was hypothesised that scores on the appearance scale may be related to wearing time. For instance, a child assigned to the contact lens group who does not like his or her appearance in glasses (that is, lower score on the scale) may be more likely to wear contact lenses longer than the child assigned to the contact lens wear group who is satisfied with his or her appearance. Likewise, a child assigned to the contact lens group who finds that spectacles interfere with recreational activities may be more likely to wear contact lenses longer (measured by the activities scale on the PREP). At the end of the study, the subjects completed a close-out form, in which they were asked the number of neighbourhood or sports teams in which they participated. Using survey responses to categorise children in these areas can address whether children in this study wore their correction as hypothesised.

Statistical methods Means and standard deviations are provided to describe wearing time in the two treatment groups (spectacles and contact lenses), as well as the total correction time for contact lens wearers (contact lens wear time plus spectacle wear time). Because of © 2010 The Authors

Journal compilation © 2010 Optometrists Association Australia


Time

Spectacles

Contacts

Number

Spectacles

Number

Contact lens wearing time

Total correction wearing time

One year

227

91.8 ⫾ 25.9

233

78.2 ⫾ 30.7

95.3 ⫾ 20.8

18 months

218

94.6 ⫾ 24.7

231

79.5 ⫾ 30.1

95.5 ⫾ 22.1

Two year

228

91.8 ⫾ 27.1

239

81.8 ⫾ 28.9

97.5 ⫾ 18.1

30 months

225

93.3 ⫾ 29.7

227

82.5 ⫾ 29.1

99.6 ⫾ 16.5

Three year

218

90.7 ⫾ 32.6

231

85.2 ⫾ 27.7

99.5 ⫾ 21.4

Table 1. Parent-completed mean wearing time per week for spectacles and contact lenses groups by visit

the repeated measurements (wearing time assessed at five visits), models that were able to account for the correlated nature of the data were necessary. Given the continuous nature of the outcome (wearing time) mixed linear models were used to account for repeated visits. Initial models considered the main effect variable (age, gender et cetera), visit, treatment group (spectacles, contact lenses or contact lenses plus spectacles) and interactions between the main effect variable and treatment group or visit. A multivariate model was built using the main effect variables that were significant (p < 0.05) in the single main effect models. All calculations were done using SAS version 9.1. RESULTS The ACHIEVE study enrolled 484 myopic subjects at five clinical sites across the country. Of these subjects, about 41 per cent were male and one-third was younger than 10 years old at the beginning of the study. Hispanics and Blacks each accounted for 20 per cent of the sample and 47 per cent of the sample was White. Table 1 shows the number of subjects in each treatment group for each visit with wearing time survey information. The average wearing time for each group is also presented in Table 1, in which there are two columns for contact lens wearers. One column is the time parents reported that their children wore their contact lenses and the second

column is the total correction wearing time (sum of the time reported for wearing contact lenses and the time reported for wearing spectacles). To test whether the average wearing time of the primary correction was similar between groups, a model of average wearing time for each treatment group across all visits was used. This indicated that on average over the study, the spectacles wearers wore their spectacles (average wearing time equals 91.5 hours per week or about 13 hour per day) longer (p < 0.0001) than the contact lens wearers (average wearing time of 80.3 hours per week or about 11 hours per day). If one accounts for the amount of time that the contact lens wearers wear their spectacles in addition to their contact lenses, the average total time wearing correction was similar (91.5 hours per week for spectacle wearers versus 97.5 hours/week for contact lens wearers) but the difference was significant (p = 0.0006) with the contact lens wearers wearing a vision correction significantly more hours than the spectacle wearers. Below are presented the models pertaining to the covariates of interest. All of the models to be discussed have a significant treatment by visit interaction indicating that wearing time for the spectacles and contact lens groups differed depending on the visit. Because the basic components of the model (visit, treatment and the visit by treatment interaction) are constant with different variables of interest (age, gender et cetera) used for each


model, it was expected that the treatment by visit interaction would be present in all models. This proved to be an accurate underlying assumption. The following details the interaction results generally for the two outcomes (wearing time and total correction wearing time). Looking at the post hoc comparisons for the spectacles versus contact lens wearing time models showed that the two treatment groups differed from each other at each visit except at three years. At three years, the contact lens wearing time approximated that in the spectacles group. Within the spectacles group, comparing across time showed that there are no time points that were different from the one-year visit (that is, mean wearing times are relatively consistent over time). For the contact lens group, the one-year wearing time was significantly less than the wearing time at year three but other visits did not differ from year one. This pattern held regardless of the covariate considered. When the outcome was total correction wearing time, models indicated that only the threeyear visit consistently differed between the spectacles and contact lens total wearing times. At three years the spectacle means were lower than total correction wearing times for contact lens wearers. Wearing times did not differ across visits within the two treatment groups separately (that is, wearing times within group were relatively stable over the visits). Table 2 presents the p-values for the analyses to determine whether each of the variables of interest was associated with either a wearing time comparison (spectacles versus contact lenses) or a total wearing time comparison (spectacles versus contact lenses plus spectacles). There is a p-value for the main effect (for example, gender) and for the gender/ treatment group interaction. In situations where this interaction is significant, only the interaction will be discussed. These p-values are shown in bold in Table 2. The following paragraphs discuss the significant model effects. Figure 1 presents wearing time by gender and visual correction, those randomised to contact lens wear and the total correction time for those in contact lenses. Clinical and Experimental Optometry 93.3 May 2010

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Main effect

Wearing time (contact lens vs. spectacles) Main effect p-value

Total wearing time (spectacles vs. contact lenses plus spectacles)

Main effect/ treatment interaction p-value

Main effect p-value

Main effect/ treatment interaction p-value

Gender

0.53

0.23

0.56

0.53

Age

0.22

0.005

0.89

0.04

Refractive error

0.0002

0.46

_ -1.89 D CLs, > Total correction CLs, < -1.89 D

65

_ -1.89 D Total correction CLs, > Spectacles, < -1.89 D CLs, < -1.89 D

90 85 80 75 70

Spectacles, Low appearance Spectacles, High appearance CLs, Low appearance

65

Total Rx CLs, Low appearance Total Rx CLs, High appearance CLs, High appearance

60

60 1 year

18 months

2 years

30 months

3 years

1 year

2 years

30 months

3 years

Visit

Visit

Figure 3. Wearing times by refractive error group and treatment group (refractive error p < 0.05, both wearing time and total wearing time)

wore their lenses less than older contact lens wearers (83.6 hours per week or 11.9 hours per day, p = 0.02). Older spectacle wearers did not differ from older contact lens wearers (p > 0.05). The total wearing time model using total wearing time found a treatment group and age effect (p = 0.04) similar to the model comparing spectacles and contact lenses only. Models controlling for the number of waking hours per day were also considered, namely, should age be related to the amount of time a subject is awake? Adjusting these models did not change the results. Refractive error was classified into two groups based on the median refractive error (less than -1.89 D and -1.89 D or greater) to determine total wearing times among subjects randomised to spectacles and contact lenses (Figure 3). Comparing primary correction, those with higher levels of myopia wore their correction on average 89.9 hours per week (or 12.8 hours per day), while those with lower levels of myopia wore their correction 81.8 hours per week (or 11.7 hours per day; p < 0.0001). A similar difference was seen when accounting for total correction wearing time (that is, those with lower refractive error wore their correction 7.2 hours less per week than those with more myopia).

18 months

Figure 4. Wearing times by appearance scale score and treatment group (appearance scale by treatment group interaction for wearing time, p < 0.05; appearance scale for total wearing time, p < 0.05)

The appearance scale from the PREP was split at the median (a score of 50 on a scale of zero to 100) with lower scores indicating lower appearance quality of life scores (Figure 4). Assessing the effect of how a child endorsed the appearance scale of the PREP on the wearing time of their spectacles or contact lenses depended on which treatment group they were assigned to (treatment group by appearance scale interaction, p = 0.03). Post hoc comparisons found that those in the spectacle group who ranked in the lower half of the appearance scale wore their correction 15.6 hours per week on average more than those contact lens wearers with low scores (p < 0.0001), and 12.9 hours per week more than those contact lens wearers with a high score (p = 0.0001). Spectacle wearers with high appearance scale scores wore their spectacles 9.1 hours per week more than those assigned to the contact lens group, who scored low on the appearance scale. The results of the modelling for total wearing time were slightly different for the appearance scale. Those with high scores on the appearance quality-of-life subscale wore correction about four hours less per week than did those with a low appearance quality-of-life subscale score (p = 0.02), with no interaction with treatment group present.


The number of sporting activities, the PREP activities scale and a subject’s spectacle satisfaction at baseline were not associated with the wearing time or the total wearing time. A multivariate model was used to assess the relevance of the variables. Using the level of refractive error, the appearance quality-of-life scale and the age group along with treatment group and visit in a multivariate model showed that the level of refractive error was related to wearing time for the spectacle and contact lens groups (p = 0.0007), with higher myopes wearing their spectacles longer. The treatment group by age group interaction was also significant (p = 0.0087), with young spectacle wearers wearing their spectacles longer than young contact lens wearers by about 18.6 hours per week (p < 0.0001) and older spectacle wearers having a longer wearing time than older contact lens wearers by about 6.0 hours per week. The interaction between treatment group and appearance score remained significant in the multivariate model as well (p = 0.04). Among those who scored low on the appearance scale, spectacle wearers wore their spectacles 17 hours per week longer than the contact lens wearers wore their contact lenses. Likewise, among those ranking the appearance scale high, spectacle wearers wore their correction longer Clinical and Experimental Optometry 93.3 May 2010

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than the contact lens wearers by about 8.4 hours per week (p = 0.03). When assessing the multivariate model for total wearing time, age group was no longer significantly associated with wearing time nor was the interaction between treatment group and age group (p = 0.74). Refractive error remained significant (p < 0.0001). The appearance scale score was statistically significant (p = 0.03), unlike the spectacles versus contact lens model where it depended on treatment group. The subjects with a lower appearance score wore their correction almost four hours more than those with a high appearance score. DISCUSSION Practitioners provide refractive correction to young myopes to help them see to do the things they need or want to do. Schoolwork, sports and other activities benefit from optimal vision and children may experience a decrease in symptoms associated with uncorrected vision. These factors lead to the assumption that children benefit more from longer periods of correction during the day. The most influential factor governing wearing time, regardless of mode of correction, was amount of refractive error. Subjects with less than approximately 2.00 D of myopia wore vision correction roughly eight hours less than those subjects with more myopia. This is likely to be due to the necessity of vision correction for higher myopes to see clearly enough to recognise friends, play sports et cetera. Given the tendency of lower myopes to wear their correction less frequently, practitioners may consider warning the parents of new myopes that children may initially lose their spectacles more often because they do not wear them all the time. Subjects who were assigned to contact lenses did not rely solely on contact lenses for vision correction. On average, they wore their lenses less than the spectacle wearers wore their spectacles but they wore vision correction, including spectacles, slightly more than just spectacle wearers. The difference in wearing time Clinical and Experimental Optometry 93.3 May 2010

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between spectacle wearers and contact lens wearers decreased over time until the difference was not clinically meaningful. On average, spectacle wearers wore their spectacles roughly 13 hours per day. The contact lens wearers wore their contact lenses roughly 11.5 hours per day but they wore vision correction (spectacles plus contact lenses) for about 13.9 hours per day. As there is a lack of data regarding wearing time in children, comparisons can be drawn only from adults. The average contact lens-wearing time for the ACHIEVE subjects is within the reported range for adults, which falls between 11 and 14 hours per day.10–13 Currently corneal refractive therapy is the only modality available that ensures full-day correction without the use of a corrective device.8,9 One might have expected more contact lens wear among subjects who participated in many sports, subjects who were not satisfied with spectacles or subjects who found spectacles difficult during activities. None of these conjectures was true. This is interesting given that this study found that children who wore contact lenses reported higher levels of self-assessed athletic competence than those who wore spectacles.2 Children may not feel the need to wear contact lenses all of the time, so that overall wearing time of contact lenses may not capture the necessity of lenses for select activities. They may wear contact lenses just when they feel they are necessary for improved convenience, such as during sporting activities or times when spectacles may seem unattractive. Surprisingly, gender also played no role in determining wearing time. We had hypothesised that girls would wear contact lenses for longer periods of time than boys because they matured at an earlier age and might be more aware of social interactions or better able to handle the rigors of contact lens care. That was not the case as boys and girls wore spectacles and contact lenses for similar amounts of time. The result related to the appearance scale of the questionnaire was counterintuitive. It would be anticipated that those who scored lower on the appearance

scale (less satisfied with their appearance) in the contact lens group would be more likely to wear their lenses longer than those in the spectacle group. This did not seem to be the case. Those with low appearance scores wore their spectacles about four hours less per week than those with high appearance scores, even after controlling for the effect of refractive error. This is interesting because the physical appearance scale on the selfperception profile for children14 was significantly associated with how the subjects felt about their contact lenses.2 It could be a question of clinical relevance as opposed to statistical significance. A four-hour per week (approximately one hour per day) difference in wearing time may have little clinical relevance. As is always the case when looking at study results, it is necessary to remember that subjects in the study may act differently by virtue of study participation. Given the nature of this long-term clinical trial, we anticipate that this effect would be small. Neither spectacles nor contact lenses yielded more meaningful total vision correction wearing time. Both are appropriate for eight- to 11-year-old myopic children and can be offered as a primary vision correction option. Children fitted with contact lenses as a primary vision correction device should also be prescribed a pair of spectacles as back-up because children typically compensate for less contact lens wearing times with spectacle wear. GRANTS AND FINANCIAL SUPPORT

This study received financial support from Johnson & Johnson Vision Care and the Vision Care Institute, LLC, which reviewed and approved the manuscript. REFERENCES 1. Walline JJ, Jones LA, Chitkara M, Coffey B, Jackson JM, Manny RE, Rah MJ et al. The Adolescent and Child Health Initiative to Encourage Vision Empowerment (ACHIEVE) study design and baseline data. Optom Vis Sci 2006; 83: 37–45. 2. 2, Walline JJ, Jones LA, Sinnott L, Chitkara M, Coffey B, Jackson JM, Manny RE et al. Randomized trial of the effect of contact lens wear on self-perception in children. Optom Vis Sci 2009; 86: 222–232.



3. Horner DG, Soni PS, Salmon TO, Swartz TS. Myopia progression in adolescent wearers of soft contact lenses and spectacles. Optom Vis Sci 1999; 76: 474–479. 4. Walline JJ, Long S, Zadnik K. Daily disposable contact lens wear in myopic children. Optom Vis Sci 2004; 81: 255–259. 5. Walline JJ, Gaume A, Jones LA, Rah MJ, Manny RE, Berntsen DA, Chitkara M et al. Benefits of contact lens wear for children and teens. Eye Contact Lens 2007; 33: 317– 321. 6. Walline JJ, Jones LA, Mutti DO, Zadnik K. A randomized trial of the effects of rigid contact lenses on myopia progression. Arch Ophthalmol 2004; 122: 1760–1766. 7. Katz J, Schein OD, Levy B, Cruiscullo T, Saw SM, Rajan U, Chan TK et al. A randomized trial of rigid gas permeable contact lenses to reduce progression of children’s myopia. Am J Ophthalmol 2003; 136: 82–90. 8. Cho P, Cheung SW, Edwards M. The longitudinal orthokeratology research in children (LORIC) in Hong Kong: a pilot study on refractive changes and myopic control. Curr Eye Res 2005; 30: 71–80. 9. Walline JJ, Rah MJ, Jones LA. The Children’s Overnight Orthokeratology Investigation (COOKI) pilot study. Optom Vis Sci 2004; 81: 407–413. 10. Dillehay SM, Miller MB. Performance of Lotrafilcon B silicone hydrogel contact lenses in experienced low-Dk/t daily lens wearers. Eye Contact Lens 2007; 33: 272–277. 11. Fonn D, Gauthier CA, Pritchard N. Patient preferences and comparative ocular responses to rigid and soft contact lenses. Optom Vis Sci 1995; 72: 857–863. 12. Long B, McNally J. The clinical performance of a silicone hydrogel lens for daily wear in an Asian population. Eye Contact Lens 2006; 32: 65–71. 13. Walker J, Young G, Hunt C, Henderson T. Multi-centre evaluation of two daily disposable contact lenses. Cont Lens Anterior Eye 2007; 30: 125–133. 14. Harter S. Manual for the Self-Perception Profile for Children. Denver: University of Denver, 1985.

Corresponding author: Dr Lisa A Jones-Jordan 338 West 10th Avenue 649 Fry Hall Columbus Ohio 43210 USA E-mail: [email protected]

APPENDIX Members of the ACHIEVE study group Ohio State University College of Optometry, Columbus, Ohio, USA Jeffrey J Walline, Karla Zadnik, Monica Chitkara, Erica Johnson, Stacy Long, Jessica Zoz, Mitchell Prinstein, Kerri McTigue, Kathryn Richdale, David A Berntsen, Kathy Reuter University of Houston College of Optometry, Houston, Texas, USA Ruth Manny, Julio Quiralte, Giselle Garza, Gaby Solis, Mamie Batres, Amber Gaume, Ailene Kim, Karen Fern, Sheila Deatherage, Chuck Dudonis Pacific University College of Optometry, Forest Grove, Oegon, USA Bradley Coffey, Lois Bighill, Jessica Chang, Pamela Wong, Tracy Jacobsen, Heather Gitchell, Tawna Roberts, Andrew Aldrich, Krisha Hall, Monica R LaDouceur, Beth Kinoshita, Becca Fleming, Julie Jochum Southern College of Optometry, Memphis, Tennessee, USA John Mark Jackson, Erin Nosel, Kristin Anderson, Russell Hart, David Damari, Nicole Patterson, Jennifer Bulmann, Blair Lonsberry, Chris Lievens, Elizabeth Snow New England College of Optometry, Boston, MA, USA Marjorie J Rah, Stacy A Lyons, Alan Kwok, Paulette Tattersall Optometry Coordinating Center, Columbus, Ohio, USA Lisa A Jones-Jordan, Linda Barrett, Loraine Sinnott Data Safety Monitoring Committee Donald O Mutti, G Lynn Mitchell, P Sarita Soni


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