This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Multi-Center Clinical Evaluation of Two Reusable Soft Contact Lenses (NCT02542072), a randomized na study. The primary outcome is Comfort.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02542072 |
| Phase | NA |
| Condition | Myopia |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | Single |
| Enrollment | 90 |
| Arms in the primary outcome | n/a |
| Lead sponsor | CooperVision, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
The study enrolled 90 participants with myopia. The primary-outcome description notes that the number analyzed differs from participant flow because of protocol deviations; the number analyzed is not reported in the registry record.
Intervention
Participants were randomized to wear a pair of comfilcon A lenses for one month as part of a crossover study. The study purpose describes comparing subjective performance after four weeks of reusable lens wear.
Comparator
The comparison lens was samfilcon A. Participants were also randomized to wear a pair of samfilcon A lenses for one month. The sequence and any details about transitions between lenses are not reported in the registry record.
Primary question
The primary outcome was subjective comfort. Ratings covered comfort after insertion, typical comfort just before removal, and overall comfort, assessed at baseline, two weeks, and four weeks. The scale ranged from 0, described as painful, to 10, described as unable to feel the lenses. The registry record lists no analysis results that answer whether ratings differed between the lenses.
In practical statistical terms, this is a within-participant comparison structure: a crossover study evaluates participants across lens conditions rather than assigning each participant to only one lens condition for the entire study. The record confirms randomization and a crossover model, but does not describe the randomization procedure, the order of lens wear, or how the analysis accounted for repeated observations from the same participant. Those details matter when interpreting a comparison because measurements from one person are generally related to one another. The posted results do not include a numerical estimate of the lens contrast or its uncertainty, so the clinical question is identifiable from the study description but cannot be answered from the analysis results listed in the registry record.
3. Trial Design
This completed study, NCT02542072, is titled Multi-Center Clinical Evaluation of Two Reusable Soft Contact Lenses. It was a randomized, single-masked, crossover study sponsored by CooperVision, Inc. The registry lists an enrollment of 90 and identifies myopia as the condition. The study began in 2015-08 and had primary completion in 2016-02. Its phase is listed as not applicable.
The two device interventions were comfilcon A and samfilcon A. Arm descriptions state that participants were randomized to wear each lens pair for one month during the crossover study. The brief summary describes the purpose as comparing subjective performance after four weeks of reusable lens wear. The registry does not describe the order in which participants received the lenses, whether a transition or washout period was used, or how masking was implemented. These design details are not reported in the registry record and should not be inferred from the crossover label alone.
The primary measure was comfort, recorded at baseline, two weeks, and four weeks. The listed secondary outcomes include comfortable wearing time via SMS, wearing times, deterioration in comfort, vision quality, overall lens handling, biomicroscopy scores, lens surface wetting, and film deposits. The record lists 18 outcome measures in total. It lists zero analyses, so these outcome descriptions should not be read as evidence that results were posted for each measure.
The participant-analysis note says the number analyzed for the primary outcome differs from participant flow because of protocol deviations. The specific analyzed count and the nature of those deviations are not reported in the registry record. A sample-size justification, details of the statistical analysis plan, and any interim analyses are also not reported.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
First Intervention (1 Month)
| Stage | Comfilcon A, Then Samfilcon A | Samfilcon A, Then Comfilcon A |
|---|---|---|
| STARTED | 44 | 46 |
| COMPLETED | 39 | 43 |
| NOT COMPLETED | 5 | 3 |
Reasons for not completing this period:
| Reason | Comfilcon A, Then Samfilcon A | Samfilcon A, Then Comfilcon A |
|---|---|---|
| Adverse Event | 1 | 1 |
| Lost to Follow-up | 2 | 0 |
| Lens discomfort | 1 | 2 |
| Protocol Violation | 1 | 0 |
Second Intervention (1 Month)
| Stage | Comfilcon A, Then Samfilcon A | Samfilcon A, Then Comfilcon A |
|---|---|---|
| STARTED | 39 | 43 |
| COMPLETED | 37 | 43 |
| NOT COMPLETED | 2 | 0 |
Reasons for not completing this period:
| Reason | Comfilcon A, Then Samfilcon A | Samfilcon A, Then Comfilcon A |
|---|---|---|
| Lost to Follow-up | 1 | 0 |
| Lens discomfort | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: Number of participants analyzed is different from participant flow due to protocol deviations.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Comfilcon A, Then Samfilcon A | Samfilcon A, Then Comfilcon A | Total |
|---|---|---|---|---|
| Participants analysed | 44 | 46 | 90 | |
| Age, Continuous | years | 32.1 (SD 9.3) | 30.8 (SD 8.0) | 31.4 (SD 8.7) |
| Sex: Female, Male: Female | Participants | 28 | 34 | 62 |
| Sex: Female, Male: Male | Participants | 16 | 12 | 28 |
6. Primary Endpoint
The registry lists the primary outcome as Comfort, measured over Baseline, 2 weeks, 4 weeks.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is labeled comfort and is a continuous measure summarized as a mean with standard deviation. The description identifies three subjective ratings: comfort after insertion, typical comfort just prior to removal, and overall comfort. Each is assessed for comfilcon A and samfilcon A at baseline, two weeks, and four weeks. The stated response scale runs from 0, meaning painful, to 10, meaning the lenses cannot be felt.
Comfort is used to capture participants’ subjective experience of wearing the lenses. The three rating prompts reflect different moments or perspectives on that experience, while repeated assessments allow the study to describe how ratings vary across the stated visits. These are general features of the measure; they do not establish which rating or visit is most informative for a particular decision.
The registry record does not specify a single summary contrast, such as a change from baseline or an average over visits, and does not state how the three ratings would be combined or analyzed. It also does not list mean values, standard deviations, an estimated difference between lenses, or an uncertainty interval. Consequently, the endpoint definition explains what was intended to be measured, but the posted results do not show the size or precision of any lens comparison.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a randomized crossover comparison and defines comfort as the primary outcome, but it does not list analysis results. In particular, it gives no numerical comfort ratings, between-lens estimate, standard deviation, confidence interval, or p-value. The tables and plots should therefore be read as presenting no posted primary-outcome comparison rather than as evidence of a particular direction or size of difference. There is no result from which to judge whether the observed ratings favored either lens or how precisely a contrast was estimated.
The record lists 18 outcome measures and zero analyses. This distinction is important: an outcome description says what investigators intended to measure, whereas an analysis result reports what the recorded measurements showed under a specified analysis. The listed secondary outcomes cover wearing time, comfort, vision, handling, and lens observations, but their presence in the registry does not establish that their results were analyzed or posted.
The primary-outcome description includes multiple comfort prompts and assessments at baseline, two weeks, and four weeks. This creates several possible ways to summarize the comfort data. Which comparison was designated as primary, and how the multiple dimensions and assessment times were handled statistically, are not reported in the registry record. The record also does not identify the sample size analyzed for the outcome; it notes that this differed from participant flow because of protocol deviations.
General statistical context: an estimate describes the size and direction of a comparison, while a confidence interval describes the range of values reasonably compatible with the data under the analysis assumptions. A p-value addresses compatibility with a specified null hypothesis under those assumptions; it does not measure the importance of a difference. None of these comparison statistics is listed for comfort in the record, so there is no basis to describe statistical significance, precision, or practical importance.
The study is marked completed, but completion status is not itself an outcome result. The design and endpoint make clear what the study set out to compare; the posted results do not supply the numerical evidence needed to characterize the comparison. Any conclusion about the relative comfort ratings would go beyond what the registry record reports.
9. Statistical Methods Explained
The record identifies a randomized, single-masked crossover design, a continuous primary outcome, and a mean with standard deviation as the outcome parameter and dispersion. It does not provide the statistical methods used to analyze the primary or secondary outcomes. The explanations below describe general statistical concepts relevant to this design; they are not claims about analyses performed in this study.
What does a crossover design imply for analysis?
In a crossover study, participants receive more than one intervention condition over time. A comparison can therefore make use of measurements from the same participant under both conditions. As a general matter, measurements from the same person are often correlated. An analysis that recognizes this within-person relationship can differ from one that treats every measurement as independent. The registry record confirms the crossover model but does not state whether the analysis used paired comparisons, a repeated-measures model, or another approach.
Sequence and period can also matter in crossover studies. Sequence refers to the order in which intervention conditions are received; period refers to the time segment in which a condition is used. General crossover analyses may examine or account for such structure when the design and data support it. The registry record does not report the sequence, any period-related analysis, or whether a carryover assessment was planned. No conclusion about those methods can be drawn from the design label alone.
What does a mean and standard deviation communicate?
For a continuous measure, the mean summarizes the average recorded value, and the standard deviation describes how spread out individual values are around that mean. These summaries can help describe a group of ratings, but they do not by themselves give the uncertainty of a between-lens contrast. In a crossover setting, the variability of within-person differences may be particularly relevant to the precision of a comparison. The record’s endpoint description names mean and standard deviation, but it does not post the actual summaries or explain how the comparison was calculated.
How should uncertainty be read?
General explanation: a confidence interval combines an estimated effect with information about its uncertainty under a stated statistical model. A narrower interval indicates greater precision than a wider interval, all else equal. A p-value is a measure of how compatible the observed data are with a specified null hypothesis, given the model assumptions. Neither a p-value nor an interval alone establishes whether a difference matters to participants. The registry record lists no confidence interval, p-value, or estimated contrast for comfort, so the precision and statistical evidence for a lens comparison cannot be assessed from the posted analyses.
What do the sample-size illustrations mean?
The sample-size section is described as a planning illustration computed from the observed effect, not as the trial’s own design justification. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the target effect is a stated fraction of the observed effect. For non-time-to-event outcomes, the section is expressed as participants per arm. These are planning calculations, not counts of participants actually analyzed, and they do not establish the power achieved in this completed study. The observed effect and the numerical planning illustrations are not reported in the registry record. The trial’s own sample-size justification is also not reported.
What can be concluded about the analysis plan?
The registry record lists zero analyses, so it does not show which statistical tests, models, covariates, or decision thresholds were used. It also does not report how repeated measures, protocol deviations, or missing outcome values were handled. In general, those choices can affect estimates and uncertainty, and an analysis plan helps readers distinguish prespecified comparisons from exploratory ones. Here, the available record supports description of the design and intended measure, but not a reconstruction of the analysis methods or their numerical results.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome includes three comfort ratings and assessments at baseline, two weeks, and four weeks. In addition, the registry lists a set of secondary outcomes and 18 outcome measures overall. When a study considers multiple outcomes, dimensions, or time points, the number of potential comparisons increases. As a general statistical matter, this can increase the chance of finding an apparently notable result by chance if many comparisons are tested without an appropriate plan. The registry record does not report a multiplicity strategy, a hierarchy of outcomes, or which comparison was intended to be the primary statistical test.
Missing-data handling is also not described. The primary-outcome population note states that the number of participants analyzed differs from participant flow because of protocol deviations. The specific number analyzed, the reasons for deviations, and their relationship to missing comfort ratings are not reported in the registry record. It is not possible to determine whether the analysis used complete cases, an imputation method, a model using available observations, or another approach.
The analysis population is not otherwise defined in the record. It does not state whether participants were analyzed according to their randomized sequence, according to lens exposure, or under another rule. These issues are especially relevant when outcomes are measured repeatedly in a crossover design. Without a reported analysis plan or analysis results, readers cannot assess how multiplicity or missing observations may have affected the estimated comparison.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Comfilcon A | 0 | 90 | 0.0% |
| Samfilcon A | 0 | 90 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Comfilcon A | 0 of 90 |
| Samfilcon A | 0 of 90 |
The adverse-event figures list 90 participants at risk for serious adverse events in the comfilcon A group and 90 in the samfilcon A group. The corresponding counts affected by serious adverse events are 0 for each group. For other, non-serious adverse events, the record likewise lists 90 at risk and 0 affected in each group. These are the registry’s posted counts; they should be interpreted as counts recorded in the adverse-event section, not as a complete description of every possible safety outcome.
Because the study is crossover, the two exposure groups may include the same participants during different lens periods. The record does not explain how the at-risk counts relate to unique participants, exposure periods, or event attribution. The counts therefore should not be added together or treated as two independent sets of participants. Death counts are not reported in the registry record.
Zero events listed in a record does not establish that the risk of an event is zero. It means that the posted table records no affected participants for the specified event categories and groups. The registry entry does not provide additional detail about event definitions, monitoring, duration of exposure, or the process used to collect safety information. These figures are descriptive and do not, by themselves, support a broader safety comparison.
12. What the Result Does, and Does Not, Mean
This record is useful for understanding the intended comparison: a randomized, single-masked crossover evaluation of two reusable soft contact lenses, with subjective comfort as the primary outcome. It defines the comfort prompts and assessment times, identifies other outcomes, and reports the study’s completed status. Those details help readers understand the question the study was designed to address.
However, the record lists zero analyses and provides no numerical primary-outcome comparison. It does not report the means, standard deviations, estimated contrast, confidence interval, or p-value for comfort. Accordingly, the posted information does not show whether comfort ratings were higher with one lens, whether any difference was small or large, or how precisely a comparison was estimated. No conclusion about which lens had better subjective performance can be drawn from the analysis information.
In general, a study’s design and endpoint describe the intended method of inquiry, while analysis results are needed to characterize the observed data. Completion of a trial does not substitute for posted results. Likewise, the absence of a listed analysis is not evidence that the lenses were equivalent, nor is it evidence that they differed. It indicates that the registry record, as, does not contain the numerical analyses needed to evaluate either possibility.
The adverse-event counts show zero affected participants listed for serious and other adverse events in each exposure group, with 90 at risk in each. These are limited descriptive counts. They do not establish that no events could occur, and the record does not report death counts or further details about safety collection. The appropriate reading is confined to the entries shown, rather than a general conclusion about safety.
13. Why This Trial Matters Statistically
Statistically, this study illustrates why a clear design description and posted analysis results are both needed. The crossover structure indicates that participants experienced both lens conditions, making within-participant information potentially relevant to the comparison. The primary outcome is subjective and measured at several points and across several comfort prompts. Those features create analytical choices about repeated observations, outcome summaries, and the comparison of interest.
The registry record identifies the design, outcome, scale, time points, and broad summaries, but lists zero analyses. It also notes a difference between participant flow and the number analyzed because of protocol deviations, without stating the analyzed count or how those deviations were handled. The contrast between a detailed outcome description and absent analysis results makes the distinction between planned measurement and reported evidence especially visible.
Multiplicity is another statistical consideration: several outcome measures and comfort assessments are listed, while no plan for prioritizing or adjusting comparisons is reported. This does not show that any particular analysis was inappropriate. It means readers cannot determine from this record which comparisons were emphasized or how multiple assessments were addressed.
Finally, the sample-size section is explicitly a planning illustration based on the observed effect and stated assumptions, rather than the trial’s own design justification. Without the numerical analysis results or the trial’s sample-size rationale, the illustrations cannot be used to infer precision achieved in the study. The record therefore offers a useful example of the limits of interpreting a completed trial from design and endpoint descriptions alone.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The most important limitation for interpreting this trial from the registry record is that it lists zero analyses. Although the primary comfort outcome and its scale are described, no outcome values or lens-comparison estimates are posted. The relative comfort ratings, their variability, and the precision of any comparison are therefore not available for interpretation.
The design description leaves several details unresolved. It confirms randomization, single masking, and a crossover model, but does not describe randomization procedures, intervention sequence, masking implementation, transition periods, or the handling of possible period or carryover effects. These details are not reported in the registry record; their absence does not establish that they were not addressed elsewhere.
The participant-analysis note says that the number analyzed differs from participant flow because of protocol deviations. The analyzed count, the deviations, the analysis population, and the treatment of missing measurements are not reported. The record also does not describe methods for repeated observations, multiplicity, or the statistical plan. With comfort measured using several prompts at several times, these omissions limit the ability to reconstruct the intended comparison.
The record lists 18 outcome measures, but zero analyses. Thus the outcome list should not be mistaken for a complete set of posted results. Safety entries are also limited: counts are reported for serious and other adverse events, but deaths, event definitions, exposure details, and collection procedures are not reported in the registry record. These limitations restrict conclusions to describing the study design and the entries actually listed.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Multi-Center Clinical Evaluation of Two Reusable Soft Contact Lenses — NCT02542072.
- Registry record last updated 2017-10-24; status last verified 2017-09.
- Results first posted 2017-03-21.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT02542072 is a completed, randomized, single-masked crossover study of comfilcon A and samfilcon A reusable soft contact lenses in participants with myopia. Enrollment is listed as 90. Participants were described as wearing each lens pair for one month. The primary outcome was subjective comfort on a 0-10 scale, assessed at baseline, two weeks, and four weeks, with ratings for comfort after insertion, typical comfort before removal, and overall comfort.
The registry lists 18 outcome measures and zero analyses. It notes that the number analyzed for the primary outcome differs from participant flow because of protocol deviations, but does not report the analyzed count. Serious and other adverse-event counts are listed as 0 affected among 90 at risk in each lens group; deaths are not reported in the registry record. Numerical primary-outcome results and details of the statistical analysis plan are not reported.