Evaluation of a Daily Disposable Novel Multifocal Contact Lens in a Myopic Population: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of a Daily Disposable Novel Multifocal Contact Lens in a Myopic Population (NCT04310566), a randomized na study. The primary outcome is Subjective Vision Scores.

2. Clinical Question

This clinical question concerns a patient-reported score, rather than an objective measure of visual acuity. The outcome is recorded in units on a scale, with higher CLUE scores representing a more favorable response. The registry reports an average score for each lens and a mean difference comparing test with control. It also reports an interval around that difference and an unadjusted p-value.

The study used a randomized crossover design, with participants assigned to one of two possible lens-wear sequences: Test/Control or Control/Test. That design makes the comparison relevant to the two lenses in the context of the study’s crossover arrangement. However, the posted outcome summary does not give sequence-specific results or explain how the statistical comparison handled the crossover structure. The registry record therefore supports a description of the reported score comparison, but not a more detailed account of effects by period or sequence.

3. Trial Design

This was a randomized, single-masked, dispensing clinical trial with a crossover model. Eligible habitual soft contact lens wearers were to be randomized into one of two sequences: Test/Control or Control/Test. The study compared the JJVC Investigational Multifocal Contact Lens (senofilcon A c3) with the Dailies Total 1® Multifocal Contact Lens. The registry lists the study as completed and gives enrollment as 67. Its brief summary says approximately 70 eligible subjects would be targeted to complete the study; that target is not the same as the enrollment figure.

The listed condition is Visual Acuity, while the primary outcome is Subjective Vision Scores. In particular, the outcome description identifies Subjective Overall Quality of Vision assessed using the CLUE questionnaire. Its timeframe is 1-Week Follow-up. The registry lists the primary outcome population as all available data.

Although the crossover model and the two sequences are specified, other design details relevant to interpreting a crossover comparison are not reported in the registry record. The record does not state the length of each lens-wear period, whether or how a washout was used, or whether period and sequence effects were assessed. It also does not describe the masking procedures beyond labeling the study single-masked. The original statistical plan, including the planned treatment of within-participant measurements, is not reported in the registry record.

The listed enrollment and the summary’s approximate completion target provide context for the trial’s scale, but they do not by themselves explain how the original design was planned. The record does not report the original sample-size assumptions or a sample-size justification. The planning figures derived from the observed comparison are separate illustrations and should not be read as the study’s original design plan.

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.

Period 1

Reasons for not completing this period:

Period 2

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All available data

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.

6. Primary Endpoint

The registry lists the primary outcome as Subjective Vision Scores, measured over 1-Week Follow-up.

The primary endpoint is Subjective Vision Scores at 1-Week Follow-up, measured in units on a scale. The description specifies that Subjective Overall Quality of Vision was assessed with the Contact Lens User Experience™ (CLUE) questionnaire. CLUE is described in the registry as a validated patient-reported outcomes questionnaire for assessing soft contact lens attributes, including comfort, vision, handling, and packaging, in a contact-lens-wearing population in the US, ages 18-65.

The reported CLUE scores are derived using Item Response Theory and are described as following a normal distribution with a population average score of 60 and SD 20. The scale ranges from 0-120, and higher scores indicate a more favorable or positive response. These features give readers a direction for interpreting the score: a higher mean represents a more favorable average reported experience on this measure, not necessarily a difference in every questionnaire attribute.

A patient-reported measure is useful when the question concerns participants’ own evaluation of their experience. Here, the endpoint captures subjective overall quality of vision rather than an examiner’s measurement. The registry record does not report separate results for the other CLUE attributes or explain the scoring procedure beyond the description of the instrument and its derived scores.

7. Results Posted in the Registry

• Test: mean 61.41 versus 55.03 on control; difference 6.38 (95% CI -3.39 to 16.15), standardized effect d = 0.34; z-test p = 0.201.

8. Statistical Interpretation

9. Statistical Methods Explained

The registry reports continuous outcome summaries as means and standard deviations. A mean describes the center of the observed scores, while a standard deviation describes their spread around that center. These measures make it possible to compare the average CLUE score between the test and control groups while retaining a sense of how variable the scores were. For the test group, the reported mean is 61.41 and standard deviation is 19.92; for the control group, the mean is 55.03 and standard deviation is 18.2.

What does the mean difference describe?

The reported mean difference is 6.38 units, calculated in the comparison as test minus control. A positive value means the test-group mean is higher than the control-group mean on the reported scale. Since higher CLUE scores are described as more favorable, the sign indicates the direction of the observed average comparison. It does not indicate how many participants had a higher score, and it does not show whether the difference is sufficiently precise to rule out other plausible values.

For a continuous outcome, the difference in means is a direct way to express how far apart the group averages are in the scale’s own units. It is often easier to interpret alongside the score range and the scale’s direction than an abstract standardized measure. The registry also reports a standardized effect-size estimate of 0.335, but its clinical meaning is not established in the record. The score difference and standardized estimate should not be treated as individual-level effects.

What does the interval add?

An interval around an estimate represents uncertainty associated with the data and analysis. In general, a narrower interval indicates greater precision, while a wider interval leaves more possible values compatible with the result. The reported interval for this mean difference runs from -3.391 to 16.15. Because it crosses zero, the data and analysis do not exclude a mean difference of zero at the interval’s stated confidence level. The registry does not specify the confidence level in the record summarized for this result, so it should not be inferred from the interval alone.

An interval is not a range containing every individual participant’s score. It concerns the estimated difference between group means. Nor does it assign a probability to a particular value of the true difference. Its interpretation depends on the statistical model and assumptions used to construct it; those details are not reported in the registry record.

How should the p-value be read?

The unadjusted p-value is 0.201. In general, a p-value measures how unusual data at least as incompatible with a specified null model would be if that model and the analysis assumptions held. It is not the probability that the null hypothesis is true, nor the probability that the result occurred by chance. The registry labels the value unadjusted, and the record does not report a multiplicity adjustment or a full analysis plan. The value should therefore be interpreted as the posted unadjusted result rather than as evidence of an unreported adjustment strategy.

Why does crossover structure matter?

In a crossover study, participants are assigned to sequences that expose them to more than one intervention. This can allow a comparison to use information from the same participants under different interventions, but it also raises analysis considerations about repeated observations, treatment periods, sequence, and possible carryover. These are general features of crossover designs, not claims about what occurred in this trial. The registry gives the Test/Control and Control/Test sequences but does not report how the primary comparison accounted for within-participant correlation, period effects, sequence effects, or carryover. No particular model should be assumed.

The reported group counts are 28 for test and 31 for control. Because the trial is identified as crossover, those figures should not be assumed to represent independent sets of participants without further information. The record does not describe the relationship between the outcome observations and the assigned sequences, so the analysis structure cannot be reconstructed from the summary alone.

Why can variation affect precision?

When scores vary widely, a difference between group averages can be estimated less precisely unless the data provide enough information to distinguish that difference from noise. This is a general statistical principle. The observed standard deviations, 19.92 and 18.2, describe score variability in the posted groups. The interval is relatively broad in scale units and includes both negative and positive differences. That uncertainty is important alongside the point estimate, rather than treating the difference alone as the complete result.

Over-dispersion is a general issue when observed variation exceeds what an analysis model assumes. It can make standard errors and intervals unreliable if the model does not account for the extra variation. The registry record does not report a dispersion assessment or a model specification, so there is no basis to state whether over-dispersion was assessed or relevant to the sponsor’s analysis.

Overall, these methods concepts help distinguish the mean difference, its uncertainty, and the p-value. The registry provides those summary statistics but does not report enough analytical detail to evaluate the model assumptions, crossover handling, or any sponsor-level inferential procedure beyond the posted result.

10. Confidence Intervals and Precision

The reported mean difference is 6.38 units, with an interval from -3.391 to 16.15. The interval communicates uncertainty around the estimated average comparison. Its lower endpoint is below zero and its upper endpoint is above zero, so the interval includes both a possible mean difference favoring the control and possible mean differences favoring the test. The point estimate alone gives a single direction; the interval shows that the estimate is not precise enough to exclude a range of other values.

Precision is different from the size or importance of an estimate. An estimate may point in one direction while remaining uncertain, and an interval can include zero without proving that there is no difference. Conversely, an interval excluding zero would not by itself establish practical importance. The registry record does not report a threshold for a meaningful difference on the CLUE scale, so the clinical importance of the interval’s values cannot be determined from the record.

The interval’s interpretation depends on its confidence level and the method used to calculate it. The record summarized for this comparison does not state the confidence level or the model details used for the reported interval. The value should therefore be described as the reported interval, without attaching an unstated level or claiming that it captures a particular probability about the true difference.

The unadjusted p-value of 0.201 is consistent with the interval’s inclusion of zero, but it does not replace the interval’s information about magnitude and direction. The standard deviations of 19.92 for test and 18.2 for control also indicate that scores varied around their means. Together, the estimate, interval, and observed spread give a more complete picture than any one statistic alone. Uncertainty also remains about the handling of the crossover design because the registry does not describe the model used for the comparison.

11. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations based on the observed mean difference, not a report of the trial’s original design. They are participants per arm, not total event counts. The calculation assumptions listed in the registry record are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set as a stated fraction of the observed effect.

For planning for 100% of the observed effect, the illustration gives 140 participants per arm for 80% power and 188 participants per arm for 90% power. For planning for 75% of the observed effect, it gives 249 participants per arm for 80% power and 333 participants per arm for 90% power. For planning for 50% of the observed effect, it gives 559 participants per arm for 80% power and 749 participants per arm for 90% power.

In plain terms, the 80% power column describes the illustrated number of participants per arm under which the assumed effect would be detected at the stated significance level in 80% of repeated studies if the calculation assumptions and effect were correct. The 90% power column uses a higher chance of detecting that assumed effect under those same conditions. Smaller target effects require more participants in these illustrations, because a smaller difference is harder to distinguish from variability.

These values are not observed power. The registry record does not report the original sample-size justification or its own design assumptions, so the illustrations should not be used to infer why the study enrolled its reported number of participants.

12. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 6.380; pooled standard deviation σ = 19.032.
2. n = 2 × (1.96 + 0.842)² × 19.032² / 6.380² = 139.7, rounded up to 140 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 6.38                      # observed difference in means
sigma <- 19.0321307419571                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(4310566)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 140 (80% power), 188 (90% power)
 75% of observed effect: n per arm = 249 (80% power), 333 (90% power)
 50% of observed effect: n per arm = 559 (80% power), 749 (90% power)
power.t.test: 140.7 
Simulated power at n = 140 per arm: 0.805 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

13. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures, but reports no posted secondary outcome results. The primary outcome is Subjective Vision Scores at 1-Week Follow-up. Although the record includes an unadjusted p-value for the primary comparison, it does not report a multiplicity plan or any adjustment for testing more than one outcome or comparison. It is therefore not possible to tell from the registry record whether multiplicity was addressed in the trial’s statistical plan or sponsor analysis.

Multiplicity is a general concern when several outcomes, time points, subgroups, or comparisons are tested. Repeated testing can increase the chance of at least one nominally unusual result even when none of the underlying effects is real. Methods for addressing this may include prespecifying a primary outcome, adjusting inference, or treating additional analyses as exploratory. The registry record does not state which approach, if any, was used beyond identifying a primary outcome and reporting an unadjusted p-value.

Missing-data details are also limited. The primary outcome population is described as all available data, but the record does not explain how many outcome observations were missing, why they were missing, or how missing values were handled. It does not report imputation, sensitivity analyses, or a comparison of participants with and without observed outcomes. Consequently, the extent to which missing data could affect the result cannot be assessed from this record.

The record lists the outcome population but does not provide enough information to identify a specific analysis population such as intention-to-treat or per-protocol. It does not describe exclusions, adherence requirements, or rules for retaining participants in the analysis. These details can matter in a randomized crossover trial, where participants may have outcomes across multiple lens periods. The registry record also does not report whether the sponsor’s analysis included all randomized participants, all participants with available measurements, or another defined group.

These omissions do not establish that the trial failed to address multiplicity or missing data; they mean the relevant procedures are not reported in the registry record. Interpretation should remain limited to the posted comparison and the stated all-available-data description.

14. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry lists serious adverse event figures separately for the test and control groups. For the test group, 45 were at risk and 0 were affected by serious adverse events; deaths are listed as 0. For the control group, 49 were at risk and 0 were affected; deaths are listed as 0. The record does not list serious adverse event terms.

These figures describe what is recorded in the registry for the listed groups. A value of 0 affected means the registry reports no participants affected in that category; it does not establish that an event was impossible or that the lenses have no safety risks. The at-risk figures are not interchangeable with the primary-outcome group counts, and the record does not explain the relationship between these safety populations and the crossover sequences.

The registry also lists 0 affected by other adverse events for each group. Safety interpretation is limited by the information reported: there are no event terms, descriptions of ascertainment, severity details, or exposure-period summaries in the registry record. These figures should be read as registry counts, not as a comprehensive assessment of safety in other settings or populations.

15. What the Result Does, and Does Not, Mean

The posted results describe average self-reported quality-of-vision scores for the test and control lenses at the 1-Week Follow-up. The test mean is 61.41 and the control mean is 55.03, with a reported mean difference of 6.38 units in the test-minus-control direction. Because higher CLUE scores indicate more favorable responses, the point estimate favors the test on this measure. The interval, from -3.391 to 16.15, includes zero, and the unadjusted p-value is 0.201. The result is therefore uncertain and does not establish a clear difference in mean scores.

That conclusion is specific to this endpoint, time point, and registry-reported comparison. It does not establish what participants experienced on every CLUE attribute, how individual participants responded, or what the scores would be at other follow-up times. The record does not report secondary outcome results, subgroup analyses, or a meaningful-difference threshold for the scale.

The result also should not be interpreted as proof that the lenses are equivalent. A nonsignificant p-value and an interval that includes zero do not demonstrate equality; they indicate that the reported comparison does not clearly distinguish the average scores given its uncertainty. Equivalence or noninferiority would require an appropriate prespecified framework and margin, neither of which is reported in the registry record.

The randomized crossover design is relevant to the comparison, but the posted summary does not explain how the analysis handled repeated observations, sequence, period, or carryover. That limits what can be said about the statistical basis of the estimate. The result is not a general statement about every myopic person, all contact lens wearers, or lens use beyond the study context. It is a registry-reported summary of a subjective score comparison, not medical advice or a recommendation about lens choice.

16. Why This Trial Matters Statistically

This trial is statistically informative because it illustrates the difference between an observed direction and a well-resolved estimate. The test group’s mean CLUE score is higher than the control group’s, and the reported difference is 6.38 units. But the interval extends from -3.391 to 16.15 and the unadjusted p-value is 0.201. Reading the point estimate alone would omit the substantial uncertainty around it.

The outcome also illustrates why measurement context matters. CLUE is a patient-reported measure with higher scores described as more favorable, and the result concerns subjective overall quality of vision at a specified follow-up. A mean score captures an average response, while the standard deviations of 19.92 and 18.2 show that scores varied among the observed groups. The average does not represent every participant’s experience.

The crossover design raises an additional statistical question. Such designs can yield repeated observations from participants across interventions, so the analysis must reflect the design structure. The registry specifies two treatment sequences but does not describe the model or its handling of periods and within-participant dependence. This gap demonstrates why design labels alone are not enough to evaluate an analysis.

Finally, the planning illustrations make clear that calculations based on an observed effect are not the same as the trial’s original design rationale. The record does not report that rationale. Keeping those distinctions clear helps prevent over-reading an uncertain estimate or mistaking a retrospective planning illustration for evidence about the study’s design quality.

17. 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.

Several trial-specific limitations follow from the information reported in the registry. The primary outcome comparison is summarized with means, standard deviations, an interval, and an unadjusted p-value, but the record does not give the statistical model or explain how the analysis treated the crossover structure. In particular, it does not report whether period, sequence, or within-participant correlation was incorporated. The reported estimate therefore cannot be independently evaluated against a detailed analysis plan from the registry record alone.

The outcome population is labeled all available data, but the registry does not state the amount or pattern of missing outcome data, or how missingness was handled. It also does not identify the analysis population with terms such as intention-to-treat or per-protocol. These omissions limit assessment of possible selection or attrition effects.

The endpoint is a subjective, patient-reported score at 1-Week Follow-up. The record does not report results for other time points or separate CLUE domains, and it gives no threshold for a meaningful score difference. Thus the statistical estimate cannot be translated into a claim about practical importance on the scale. No secondary results or analysis results beyond the posted comparison are reported.

The registry gives enrollment as 67, while its summary describes a target of approximately 70 subjects to complete the study. It does not explain the relationship between those figures or report the number completing each sequence. The original sample-size assumptions and justification are also not reported. The planning figures based on the observed effect do not fill that gap.

Finally, the registry’s safety counts are limited to the categories and populations listed, without event terms or further context. These reporting limits mean the posted results support a narrow statistical description, rather than a full assessment of the trial’s conduct, analysis, or broader applicability.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Evaluation of a Daily Disposable Novel Multifocal Contact Lens in a Myopic Population — NCT04310566.
• Registry record last updated 2022-01-19; status last verified 2021-12.
• Results first posted 2022-01-19.
• 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.

21. Record Summary

The registry record identifies a completed, randomized, single-masked crossover dispensing trial of a novel multifocal contact lens in a myopic population. Enrollment is listed as 67, and the primary outcome is Subjective Vision Scores on the CLUE questionnaire at 1-Week Follow-up.

The reported means are 61.41 for test and 55.03 for control. The mean difference is 6.38, with an interval from -3.391 to 16.15 and an unadjusted p-value of 0.201. Higher CLUE scores indicate a more favorable response, but the interval includes zero and leaves uncertainty about the direction and size of the underlying mean difference.

The registry does not report the detailed crossover analysis, missing-data procedures, multiplicity approach, or original sample-size justification. No secondary outcome results are posted.