DAILIES TOTAL1 Versus ACUVUE TruEye - Effects on the Biology of the Ocular Surface and Lid Margin: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for DAILIES TOTAL1 Versus ACUVUE TruEye - Effects on the Biology of the Ocular Surface and Lid Margin (NCT02347631), a randomized na study. The primary outcome is Desquamation Rate of Wearing Alcon DAILIES, Then AcuVue TruEye Contact Lenses.

2. Clinical Question

3. Trial Design

The registry describes a prospective, randomized, single-center, bilateral crossover dispensing trial. In a crossover design, participants receive more than one study condition in sequence, so comparisons can use observations from the same participants under different conditions. The record’s outcome description states that participants first completed a one-month washout, wore Alcon DAILIES contacts for two months, completed a second one-month washout, and then wore ACUVUE TruEye contacts for two months. The registry also says the sequence was randomized and single masked; it does not identify who was masked.

The recorded enrollment is 118. The study summary describes a proposed duration of 12 months, enrollment of up to 94 established contact lens wearers, and anticipated completion of 84. These are distinct statements in the record, and it does not explain their relationship to the enrollment figure or the 39 observations reported for each lens condition in the primary outcome. The study is marked completed. Its recorded start is 2016-04 and primary completion is 2018-06.

The study compares DAILIES TOTAL1 with ACUVUE TruEye, both described as daily disposable lenses. The summary says the purpose was to evaluate changes in corneal epithelial biology over two months of daily wear and to relate those changes to the lid wiper, tear film, and cellular changes at the limbus. The posted primary outcome is desquamation rate. The registry record does not report the original sample-size justification, the exact randomization procedure, the masking procedure, or the statistical plan for the crossover comparison. It also does not report whether period or sequence effects were assessed.

The outcome timeframe is labeled “Baseline + 3 months,” while the outcome description sets out two-month wear periods separated by washouts. The registry does not clarify the relationship between that timeframe label and the detailed schedule. The record identifies two outcome measures but provides no posted secondary outcome analysis.

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.

Before assignment: 118 patients were randomize for the study. This is a crossover to compare patients who wear DAILIES contact lenses first, then TruEye contact lenses, vs. patients who wear TruEye contacts first, them DAILIES contact lenses second.

Washout 1 (1 Month)

First Intervention (2 Months)

Reasons for not completing this period:

Washout 2 (1 Month)

Reasons for not completing this period:

Second Intervention (2 Months)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All participants completed a 1 mo. washout 1 and wore the 1st set of contact lenses (Alcon DAILIES), then completed a second 1 mo. washout, and wore a 2nd set of contact lenses (Acuvue TRUEYE).

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 Desquamation Rate of Wearing Alcon DAILIES, Then AcuVue TruEye Contact Lenses, measured over Baseline + 3 months.

The primary endpoint is the rate of desquamation of corneal epithelial cells, measured in cells/min. Desquamation refers to the shedding of epithelial cells from the corneal surface. The registry identifies the endpoint as a mean with standard deviation as its dispersion measure. It describes assessment after lens wear and includes baseline assessments around the washout and wear periods.

As a continuous measure, the endpoint can capture differences across a range of values rather than placing participants into categories. Comparing mean rates gives a summary of the average measured cell-shedding rate during each lens condition. The endpoint is relevant to the stated aim of examining corneal epithelial biology during daily contact lens wear. The study summary also says the investigators intended to correlate changes with alterations in the lid wiper, tear film, and cellular changes at the limbus, but the posted results do not provide those analyses.

The primary outcome reports a mean of 53.86 cells/min for Alcon DAILIES TOTAL1 and 54.05 cells/min for ACUVUE TruEye. The registry reports a mean difference and confidence interval for the comparison. Those statistics describe the observed difference and its uncertainty; they do not establish that the lenses differ in other biological measures or in outcomes not posted in the record. Details about the measurement technique, assessor procedures, and handling of repeated measurements are not reported in the registry record.

7. Results Posted in the Registry

• ACUVUE TRUEYE Contact Lenses: mean 54.05 versus 53.86 on control; difference 0.19 (95% CI -5.34 to 5.72), standardized effect d = 0.02; z-test p = 0.946.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: each observation is a desquamation rate measured in cells/min. A mean describes the arithmetic center of a set of measurements. A standard deviation describes the spread of individual observations around that mean. These are different quantities: the standard deviation concerns variation among observations, while a confidence interval concerns uncertainty around an estimated quantity such as a mean difference.

What does the mean difference represent?

The posted comparison gives a mean difference of 0.19 cells/min. The two reported condition means are 53.86 and 54.05 cells/min. The comparison is framed as ACUVUE TruEye relative to Alcon DAILIES TOTAL1, so the positive estimate corresponds to a higher reported mean in the ACUVUE TruEye condition. This is a descriptive direction for the posted estimate, not a conclusion that one lens produces a reliable increase. The estimate is small relative to its uncertainty, and the confidence interval includes zero.

What does a confidence interval tell the reader?

General statistical explanation: a confidence interval represents the uncertainty associated with an estimate under the assumptions of the method used to calculate it. It is not a range containing a fixed proportion of individual participants’ measurements, and it is not a guarantee that the true value lies inside the displayed limits. In this comparison, the 95% confidence interval runs from -5.343 to 5.723. Because the interval includes zero and values in both directions, the posted result is not precise enough to distinguish a difference from no difference using the displayed estimate alone.

How should the p-value be read?

The reported unadjusted p-value is 0.946. General statistical explanation: a p-value describes how unusual data at least as inconsistent with a specified null hypothesis would be if that null hypothesis and the analysis assumptions were true. It is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of a difference. The registry labels this value unadjusted. Whether any multiplicity adjustment was planned or applied is not reported in the registry record.

Why does crossover structure matter?

General statistical explanation: crossover studies expose participants to more than one condition, allowing within-participant comparisons. Measurements from the same participant can be correlated, so a suitable analysis generally needs to reflect that relationship rather than treating every measurement as independent. Period and sequence can also matter if outcomes vary over time or if the order of conditions is relevant. The registry describes randomization, two lens periods, and washouts, but does not report the analysis model or whether it accounted for within-participant correlation, period, sequence, or carryover. The posted comparison therefore cannot be fully evaluated as a crossover analysis from the reported summary statistics alone.

What does variation tell us?

The reported standard deviations are 13.0 for Alcon DAILIES TOTAL1 and 11.91 for ACUVUE TruEye. General statistical explanation: substantial variation in observations can make a mean comparison less precise, particularly when the number of analyzed observations is limited. The standard deviations describe the observed spread, but they do not by themselves show whether the comparison was adequately powered. The posted outcome reports 39 observations for each condition. The record does not explain how those observations relate to the total enrolled population or whether every participant contributed measurements to both conditions.

The comparison also reports a pooled standard deviation of 12.47 and a standardized effect estimate of 0.015. A pooled standard deviation combines variability across conditions into a common scale for the reported standardized effect. General statistical explanation: standardization can help describe the size of a contrast relative to observed variation, but it does not replace the original-unit difference or its confidence interval. The registry’s analysis details do not state how this pooled summary relates to participant pairing in the crossover design.

The registry reports no posted analysis count, although it includes a primary comparison summary. The analysis method, any covariate adjustment, treatment of missing observations, and analysis population are not reported in the registry record. Consequently, interpretation should stay with the reported means, mean difference, confidence interval, and p-value rather than assuming details about the statistical model.

10. Confidence Intervals and Precision

The mean difference is reported as 0.19 cells/min, with a 95% confidence interval from -5.343 to 5.723. This interval includes zero and extends in both directions. It therefore conveys uncertainty not captured by the point estimate alone: the posted results are compatible with a lower mean in the ACUVUE TruEye condition or a higher mean in that condition, relative to Alcon DAILIES TOTAL1.

Precision is not the same as whether a result crosses a significance threshold. The interval’s inclusion of zero means the displayed estimate does not establish a difference at the conventional two-sided 0.05 level. Its breadth also means the data do not tightly determine the magnitude or direction of the contrast. The registry does not state a threshold for a meaningful biological difference, so the interval cannot be classified as ruling out all important differences.

The condition means are 53.86 and 54.05 cells/min, with standard deviations of 13.0 and 11.91. Those standard deviations describe observation-level spread, not the precision of the difference itself. The comparison reports 39 observations for each condition. Because the trial is described as a crossover, the relationship between paired observations could affect the uncertainty estimate; the registry does not report whether or how that relationship was modeled.

The confidence interval is a reported comparison statistic, but the registry does not give enough detail about the analysis model, missing data, or analysis population to independently assess its assumptions. The interval should therefore be read as the uncertainty reported for the posted comparison, not as an assurance that every design feature has been accounted for.

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 fractions of the observed effect, not counts of observed participants. For this continuous outcome, the figures are participants per arm. The separate convention for time-to-event outcomes would be total events, but that does not apply to this outcome.

The listed planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each row uses a stated fraction of the observed effect as the effect to detect. The figures give the number of participants per arm associated with 80% power and 90% power under those assumptions. In plain language, the 80% column is the planned per-arm size for an 80% chance of detecting the assumed effect if that effect and the planning assumptions hold; the 90% column corresponds to a higher planned chance of detection under those same conditions.

The rows consider planning for 100% of the observed effect, 75% of the observed effect, and 50% of the observed effect. Smaller assumed effects require more participants to detect under the same assumptions. The displayed counts are very large because the observed mean difference is small relative to the variability in the outcome. These figures are not the trial’s original design justification, which is not reported in the registry record, and they are not observed power.

The table is a planning exercise rather than a description of the trial’s enrollment or analyzed observations. The record reports an enrollment of 118 and 39 observations in each lens condition for the primary outcome. Those figures answer different questions from the illustrative per-arm sample sizes.

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 = 0.190; pooled standard deviation σ = 12.467.
2. n = 2 × (1.96 + 0.842)² × 12.467² / 0.190² = 67,584.7, rounded up to 67,585 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 <- 0.189999999999998                      # observed difference in means
sigma <- 12.4669182238435                     # 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(2347631)
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 = 67,585 (80% power), 90,477 (90% power)
 75% of observed effect: n per arm = 120,151 (80% power), 160,848 (90% power)
 50% of observed effect: n per arm = 270,339 (80% power), 361,908 (90% power)
power.t.test: 67585.7 
Simulated power at n = 67,585 per arm: 0.797 (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 it posts a primary outcome comparison and no secondary outcome analyses. The study summary describes an interest in corneal epithelial biology and in correlating changes with the lid wiper, tear film, and cellular changes at the limbus. Results for those additional measures are not reported in the registry record. It is therefore not possible to assess whether they were measured, analyzed, or omitted from the posted results.

Multiplicity arises when several outcomes, comparisons, time points, or analyses are examined. General statistical explanation: considering many tests can increase the chance that at least one result appears statistically notable by chance. The posted primary comparison is labeled with an unadjusted p-value of 0.946. Whether the study prespecified a multiplicity strategy, adjusted any results, or treated the primary outcome as the sole confirmatory analysis is not reported in the registry record. No multiplicity correction should be assumed.

The registry describes a crossover design with two lens periods and washouts. It does not report whether the analysis included participant-level pairing, period, sequence, or carryover terms. It also does not describe the statistical model or any covariate adjustment. These omissions matter because the analysis approach affects how the comparison’s uncertainty should be understood in a crossover trial.

The outcome population description says all participants completed the first washout and wore the first lens set, then completed the second washout and wore the second lens set. The posted primary outcome nevertheless reports 39 observations in each condition, while recorded enrollment is 118. The registry does not explain the relationship between these counts, whether observations were excluded, or which analysis population was used. The number and reasons for missing outcome observations, the method used to handle missing data, and whether the analysis followed an intention-to-treat or per-protocol principle are not reported in the registry record.

These reporting gaps do not change the values in the posted comparison, but they limit the ability to assess selection, attrition, and analytic choices. Conclusions should remain confined to the reported primary outcome summary.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse events considered related to the lens condition in 0 of 118 participants for Alcon DAILIES TOTAL1 and 0 of 118 for ACUVUE TruEye. It reports other adverse events considered related in 2 of 118 for Alcon DAILIES TOTAL1 and 0 of 118 for ACUVUE TruEye. Deaths are reported as 0 in both groups.

These counts should be read as the adverse-event figures recorded for each lens condition, not as evidence that no adverse events of any kind occurred. The “other” adverse-event counts differ between conditions in the registry, while no related serious events or deaths are listed. The record does not provide further event descriptions in the posted summary, and the top serious event terms list is empty.

The figures are descriptive. They do not establish that an event was caused by a lens, nor do they provide a comparative safety estimate with uncertainty. The registry does not report additional detail about event definitions, duration of safety follow-up, or how attribution was determined. The counts should therefore be interpreted within the limits of the adverse-event information posted.

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

The central posted finding is that the average desquamation rates were close in the two lens conditions: 53.86 cells/min for Alcon DAILIES TOTAL1 and 54.05 cells/min for ACUVUE TruEye. The reported mean difference is 0.19 cells/min, with a 95% confidence interval from -5.343 to 5.723 and an unadjusted p-value of 0.946. The point estimate is near zero, but the interval includes differences in either direction.

This result does not establish that the lenses have identical effects. A comparison that does not establish a difference is not, by itself, evidence of equivalence. Equivalence or noninferiority conclusions require an appropriate design and a prespecified margin; such a margin is not reported in the registry record. The confidence interval also does not exclude every potentially meaningful difference because the record does not define what magnitude would be biologically important.

The finding concerns the posted primary outcome: corneal epithelial cell desquamation measured in cells/min. It does not answer the additional questions described in the study summary about the lid wiper, tear film, or limbal cellular changes, because no secondary outcome analysis is posted. Nor does the comparison address contact lens outcomes beyond the specified study periods or people outside the recorded study population.

The trial is described as randomized and crossover, but the record does not describe the model used to analyze repeated observations or whether period and sequence were considered. This limits evaluation of how the reported uncertainty accounts for the study design. The result should be understood as the registry’s posted comparison, with the analysis details that are available, rather than as a complete account of the trial’s statistical methods.

The safety record reports no related serious adverse events or deaths in either condition and reports 2 other related adverse events in the Alcon DAILIES TOTAL1 condition and 0 in the ACUVUE TruEye condition. Those counts are limited descriptive information and do not resolve the primary outcome question or characterize all possible safety outcomes.

16. Why This Trial Matters Statistically

This trial is statistically interesting because it uses a crossover design to compare two lens conditions within a study that focuses on biological measurements. In general, crossover designs can make within-participant contrasts informative because participants experience more than one condition. At the same time, repeated measurements create analytic questions about pairing, period, sequence, and possible carryover. The registry describes washout periods but does not report how these design features were handled in the analysis.

The reported mean difference is 0.19 cells/min, while the 95% confidence interval runs from -5.343 to 5.723. This illustrates why a point estimate alone is not enough: an estimate close to zero can coexist with uncertainty that spans differences in both directions. The reported p-value of 0.946 indicates that the displayed comparison does not provide evidence of a difference under the usual null-hypothesis test, but it does not establish equivalence.

The result also highlights the distinction between planned sample size and observed outcome data. The registry’s planning illustration uses fractions of the observed effect and lists participants per arm. It is separate from the original study design assumptions, which are not reported. In particular, the trial’s recorded enrollment and the number of posted observations per condition should not be confused with the much larger illustrative planning figures.

Finally, the record’s stated interests extend beyond the one primary outcome comparison. The absence of posted secondary analyses means that statistical conclusions must remain narrow. Transparent reporting of the analysis population, missing-data handling, and crossover model would help readers assess how firmly the primary estimate represents the intended comparison.

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.

The registry record leaves several trial-specific questions unresolved. It reports an enrollment of 118, while the study summary describes enrollment of up to 94 and anticipated completion of 84. The primary outcome has 39 observations for each lens condition. The record does not reconcile these counts or explain how many participants contributed data to both conditions.

The study is described as a randomized crossover trial with washouts between lens periods, but the statistical model is not reported. In particular, the record does not say whether paired measurements, period, sequence, or carryover were addressed. The number and reasons for missing measurements, the missing-data method, and the analysis population are also not reported in the registry record.

The outcome timeframe is labeled “Baseline + 3 months,” while the description refers to two months of wear for each lens condition and washout periods. The record does not clarify how the timeframe label maps to the measurement schedule. It also does not describe the measurement procedure or assessor methods for determining desquamation rate.

The study summary discusses possible correlations with the lid wiper, tear film, and limbal cellular changes, but no secondary outcome analyses are posted. The registry does not report the original sample-size justification, the statistical plan, a clinically or biologically meaningful difference, or any equivalence margin. These limits constrain interpretation of the primary comparison and prevent broader conclusions about other planned biological measures.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: DAILIES TOTAL1 Versus ACUVUE TruEye - Effects on the Biology of the Ocular Surface and Lid Margin — NCT02347631.
• Registry record last updated 2020-12-10; status last verified 2020-11.
• Results first posted 2020-12-10.
• 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 describes a completed, randomized, single-masked, single-center bilateral crossover trial comparing Alcon DAILIES TOTAL1 with ACUVUE TruEye daily disposable contact lenses. Its primary outcome is the mean rate of corneal epithelial cell desquamation in cells/min. The posted means are 53.86 and 54.05, respectively, with a reported mean difference of 0.19 and a 95% confidence interval from -5.343 to 5.723. The unadjusted p-value is 0.946.

The record reports 39 observations per condition and an enrollment of 118. It also reports no related serious adverse events or deaths in either condition, and 2 other related adverse events for Alcon DAILIES TOTAL1 compared with 0 for ACUVUE TruEye. No secondary outcome analysis is posted. Details of the crossover analysis, missing-data handling, analysis population, and original sample-size justification are not reported in the registry record.