Product Performance of a New Silicone Hydrogel Contact Lens: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Product Performance of a New Silicone Hydrogel Contact Lens (NCT04901897), a randomized na study. The primary outcome is Mean Change in logMAR Contact Lens Visual Acuity.

2. Clinical Question

This question is about a measured visual-acuity outcome over the stated follow-up period, not about long-term outcomes. The record identifies myopia as the condition and describes daily disposable lens wear as the use setting. It does not report whether participants wore every assigned lens as intended, how adherence was assessed, or how any departures from the assigned lens were handled. Those details are not reported in the registry record.

3. Trial Design

The registry record describes a randomized, single-masked, parallel-group study of three device interventions. The arms were kalifilcon A, delefilcon A, and senofilcon A daily disposable contact lenses. Total enrollment was 805. The posted arm sizes for the primary outcome were 398 for kalifilcon A, 202 for delefilcon A, and 205 for senofilcon A. These outcome-specific counts need not describe every stage of participation or every analysis population; the record does not give a participant-flow account.

The study status is completed. Its recorded start date was 2019-07-31, and its primary completion date was 2019-10-09. The primary outcome timeframe is baseline and 2 Week Follow up. The stated objective was to evaluate the product performance of kalifilcon A compared with the two named daily disposable lenses when worn by current soft contact lens wearers on a daily disposable basis.

Randomization means that assignment is intended to use a chance-based process, which can help create comparable groups on average. The registry record does not report the randomization procedure, whether allocation was concealed, or how assignment was implemented. Single masking indicates one masking designation, but the record does not identify who was masked or describe the masking procedure. The parallel model means the interventions were assigned in separate groups rather than described as a crossover comparison; the record does not provide more detail about participant schedules or lens-wear sequences.

The phase is listed as not applicable. The sponsor is Bausch & Lomb Incorporated. There are three posted outcome measures and no posted analysis entries. The statistical analysis plan, the original sample-size justification, planned interim analyses, and detailed analysis populations are not reported in the registry record. The record also does not state how missing outcome values or protocol deviations were to be handled.

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.

Overall Study

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 Mean Change in logMAR Contact Lens Visual Acuity, measured over Baseline, 2 Week Follow up.

The primary endpoint is mean change in logMAR contact lens visual acuity, with measurements at baseline and 2 Week Follow up. logMAR is the logarithm of the minimum angle of resolution, a scale used to express visual acuity. The endpoint expresses the average within-arm change over the stated assessment interval and supports comparisons of that average change between the lens groups.

A continuous endpoint retains information about the magnitude of measured differences rather than reducing observations to categories such as improved or not improved. Reporting a mean describes the group’s average change, while a standard deviation describes how spread out participant-level values are around that mean. Neither summary alone describes every participant’s experience or the full shape of the outcome distribution.

The registry record gives mean changes for each arm and identifies standard deviation as the dispersion measure. The posted means are -0.056 for kalifilcon A, -0.069 for delefilcon A, and -0.069 for senofilcon A. The outcome description does not state a threshold for a clinically important change, and no such threshold is reported in the registry record. Therefore, the numerical estimates can be described as differences in average measured change, but their clinical importance cannot be determined from the reported endpoint information alone.

The record calls the measure logMAR but does not provide additional details about the measurement procedure, assessment conditions, or handling of repeated measurements. These details are not reported in the registry record. Interpretation should remain tied to the stated measure and timeframe rather than extending the result to longer-term performance.

7. Results Posted in the Registry

• Delefilcon A: mean -0.07 versus -0.06 on control; difference -0.01 (95% CI -0.03 to -0.00), standardized effect d = -0.18; z-test p = 0.040.
• Senofilcon A: mean -0.07 versus -0.06 on control; difference -0.01 (95% CI -0.03 to -0.00), standardized effect d = -0.18; z-test p = 0.036.

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean change represent?

A mean change summarizes the average difference between measurements at the stated follow-up and baseline within an arm. It is a group-level quantity: a mean does not imply that each participant changed by the same amount, nor does it show the distribution of individual changes. In this study, the endpoint is continuous and the posted dispersion measure is the standard deviation. General statistical interpretation: a standard deviation describes variability among measured values around their mean, whereas a standard error describes uncertainty in an estimated mean. The record posts arm means and standard deviations and also gives standard errors for the arm means in the comparison summaries.

The registry identifies the primary outcome timeframe as baseline and 2 Week Follow up. The posted mean changes are -0.056, -0.069, and -0.069 for kalifilcon A, delefilcon A, and senofilcon A, respectively. The group summaries do not reveal the participant-level distribution, whether it is symmetric, or whether unusual observations influenced the means. Those details are not reported in the registry record.

How should the mean differences be read?

The comparison summaries report mean differences of -0.013 for delefilcon A versus kalifilcon A and -0.013 for senofilcon A versus kalifilcon A. The comparisons use kalifilcon A as the reference, and the estimates correspond to the difference between the comparator-arm mean and the reference-arm mean. A negative estimate therefore indicates that the comparator group’s posted mean change is lower on the numerical logMAR scale than the kalifilcon A group’s posted mean change.

General statistical explanation: a difference in means gives a direct estimate of the average separation between two groups on the outcome’s measurement scale. It is distinct from a standardized effect size, which expresses a difference relative to variability. The posted standardized effect estimates are -0.178 for delefilcon A and -0.180 for senofilcon A. These values describe standardized separation, but the record does not specify a clinical interpretation threshold for them.

What do the p-values contribute?

The comparison p-values are unadjusted: 0.04 for delefilcon A and 0.036 for senofilcon A. General explanation: a p-value is calculated under a null hypothesis and a statistical model, and it indicates how unusual results at least as extreme as those observed would be under that model. It does not state the probability that a treatment effect is real, the probability that the result will be replicated, or the clinical importance of an estimate. The registry record does not report the test specification, any covariate adjustment, or the prespecified analysis procedure.

Unadjusted means the reported p-values are not presented as corrected for a collection of comparisons. Since the record contains comparisons of both comparator lenses with kalifilcon A, multiplicity is a relevant interpretive consideration. The statistical plan and any adjustment strategy are not reported in the registry record. The posted p-values should therefore be read as the reported unadjusted summaries, not as evidence that a particular family-wise error approach was used.

Why use confidence intervals?

A confidence interval gives a range of values compatible with the data and the interval procedure under its assumptions. It conveys uncertainty about an estimated mean difference, rather than only classifying the result by a p-value. General explanation: a narrower interval indicates greater statistical precision, while a wider interval indicates greater uncertainty. A confidence interval is not a guarantee that the true value lies within its endpoints, and it does not automatically distinguish clinically important from unimportant effects.

For both comparisons, the posted confidence interval lies below zero and has an upper endpoint close to zero. That pattern conveys uncertainty over a range of negative differences that approaches the null value. The original endpoint bounds are more finely reported than the limit on decimal places for this explanation, so their exact values are not repeated. No clinical threshold is reported against which to judge the interval’s range.

What does the standard deviation add?

The arm-level standard deviations are reported as 0.073 for kalifilcon A, 0.073 for delefilcon A, and 0.072 for senofilcon A. General explanation: standard deviations describe dispersion among participant measurements and help contextualize how large an average difference is relative to the observed variability. They are not confidence intervals and do not express the uncertainty of a mean difference by themselves. The comparison summaries also report pooled standard deviations and standardized effects, but the registry does not state the model used to generate the estimates.

What can be inferred from the comparison design?

Randomized allocation can support causal comparisons when assignment is implemented as intended and follow-up, outcome measurement, and analysis preserve the benefits of randomization. General explanation: randomization aims to balance measured and unmeasured characteristics across groups in expectation; it does not guarantee exact balance in a particular sample. Masking may reduce some forms of measurement or behavior bias, but the record does not identify who was masked or how masking was maintained. The record also does not report allocation concealment or the procedures used to assess outcomes.

The study is described as parallel, with three device arms. The primary outcome summaries report 398, 202, and 205 participants in the respective arms. The record does not provide a participant flow diagram, missing-outcome counts, adherence summaries, or protocol-deviation counts. It is not possible to establish from the posted information whether all randomized participants contributed to the primary endpoint or whether the reported counts correspond to a particular analysis population.

What statistical details remain unknown?

The registry record does not report the primary analysis model, whether baseline values were incorporated as covariates, how standard errors and intervals were calculated, or whether any transformations or robustness checks were used. It does not report the trial’s original sample-size assumptions, the planned type I error handling, interim monitoring, or prespecified subgroup analyses. No such details should be inferred from the posted summary statistics alone.

The sample-size illustration uses an explicitly stated planning framework based on the observed effect. It is not the trial’s original design justification. General explanation: planning calculations depend on assumptions about the effect to detect, variability, allocation, significance level, and statistical model. Changing those assumptions can change the required sample size. This explains why planning figures are conditional illustrations rather than descriptions of what the trial was originally designed to establish.

10. Confidence Intervals and Precision

The comparison estimates are -0.013 for delefilcon A versus kalifilcon A and -0.013 for senofilcon A versus kalifilcon A. Each has a confidence interval entirely below zero, with the upper endpoint close to zero. The intervals indicate uncertainty around the estimated differences; they do not identify one exact value as certain. Their proximity to zero at the upper end is important because values near zero represent little or no separation in the mean-change scale.

General explanation: confidence intervals combine an estimate with a measure of its statistical uncertainty. Their width depends on factors such as variability, sample size, and the interval method. A confidence interval is not a range containing a stated proportion of individual participant outcomes. It is also not a measure of clinical importance unless interpreted alongside a suitable clinical threshold.

The posted arm counts are 398 for kalifilcon A, 202 for delefilcon A, and 205 for senofilcon A. The comparison summaries report standard errors for the arm means of 0.004 and 0.005 in the delefilcon A comparison, and 0.004 and 0.005 in the senofilcon A comparison. The record does not explain the interval construction or provide enough analysis detail to independently assess the assumptions behind it.

The registry record does not report a minimally important difference or another clinical benchmark. Consequently, the interval’s statistical position relative to zero can be described, but the range cannot be classified as clinically important or unimportant on the basis of a registry-defined threshold. The record also does not report multiplicity-adjusted intervals. The displayed uncertainty is therefore best interpreted as attached to each posted comparison separately, with the broader issue of multiple comparisons unresolved in the record.

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 illustration gives participants per arm for 80% power and participants per arm for 90% power. These are not total participants across the two arms and are not total event counts. The endpoint is continuous, so the figures are participants per arm. They are planning illustrations based on the observed effect, not observed power and not the trial’s original design justification.

The stated planning assumptions 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 to the stated fraction of the observed effect. The registry record does not report the assumptions used for the trial’s original design or its sample-size justification.

The 80% power column gives the number of participants per arm that the illustration estimates would be needed to have an 80% chance of detecting the specified effect under those assumptions, if that effect were the true one. The 90% power column gives the corresponding per-arm planning count for a 90% chance under those assumptions. These power levels are design targets in a hypothetical planning calculation, not probabilities that the reported result is correct.

The rows consider planning for 100% of the observed effect, planning for 75% of the observed effect, and planning for 50% of the observed effect. The smaller the effect targeted for detection, the more participants the illustration requires. This is because a smaller difference is harder to distinguish from random variation when other assumptions remain fixed. Read each comparison’s figures in the context of its own observed effect and the stated assumptions; they are not evidence that the study was originally designed using these values.

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 = -0.013; pooled standard deviation σ = 0.073.
2. n = 2 × (1.96 + 0.842)² × 0.073² / -0.013² = 493.7, rounded up to 494 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 <- -0.013                      # observed difference in means
sigma <- 0.0729022231976309                     # 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(4901897)
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 = 494 (80% power), 661 (90% power)
 75% of observed effect: n per arm = 878 (80% power), 1,175 (90% power)
 50% of observed effect: n per arm = 1,975 (80% power), 2,644 (90% power)
power.t.test: 494.6 
Simulated power at n = 494 per arm: 0.806 (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 primary endpoint has two posted comparisons: delefilcon A versus kalifilcon A and senofilcon A versus kalifilcon A. The associated p-values are reported as unadjusted. The registry record does not report whether the trial’s statistical plan controlled the chance of false-positive findings across these or any other comparisons, whether a hierarchy was specified, or whether any correction was used in the sponsor’s analysis. This matters because evaluating multiple hypotheses can change how individual p-values should be interpreted as a set.

The record lists three outcome measures and no posted analysis entries. It does not identify which outcomes, if any, were designated secondary in the analysis plan, nor does it describe prespecified subgroup analyses. The number and definition of all hypotheses considered by the investigators are not reported in the registry record. Therefore, the posted unadjusted p-values should not be treated as a complete account of multiplicity handling.

Missing-data methods are also not reported in the registry record. The outcome arm counts are 398, 202, and 205, but the record does not state how many participants had missing baseline or follow-up values, how incomplete records were treated, or whether any imputation or sensitivity analysis was conducted. It does not describe whether participants were analyzed according to randomized assignment, actual lens use, or another population definition.

General explanation: missing outcomes can affect both the estimate and its uncertainty when the participants with observed results differ systematically from those with missing results. Analysis-population definitions can also influence interpretation, particularly if exclusions occur after randomization. The registry record does not provide the information needed to assess these possibilities. The analysis plan, population definitions, protocol-deviation handling, and missing-data sensitivity analyses are not reported in the registry record.

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 posted serious adverse event counts are zero in each arm: kalifilcon A, delefilcon A, and senofilcon A. The number at risk for the serious-event summaries is 398, 202, and 205, respectively. The record also reports zero other adverse events for each arm and zero deaths in each arm. No serious adverse event terms are listed.

These counts describe the events recorded in the registry for the stated groups. A zero count does not establish that an event is impossible, nor does it establish that the groups have identical safety profiles. General explanation: when event counts are low or absent, uncertainty about the underlying event rate can remain, and comparisons may be limited by the amount of follow-up and the size of the groups.

The registry record does not report detailed event definitions, duration of safety follow-up, event-collection procedures, or a statistical comparison of adverse events. It also does not provide further context about exposure time or individual event narratives. The posted counts should therefore be read as registry-reported counts rather than as a complete evaluation of safety or as a basis for conclusions beyond the reported events and groups.

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

The results describe mean change in logMAR contact lens visual acuity from baseline to 2 Week Follow up for three daily disposable lens groups. The posted arm means were -0.056 for kalifilcon A and -0.069 for each of delefilcon A and senofilcon A. The two mean-difference estimates, each -0.013, compare the comparator arms with kalifilcon A. These are group averages and do not describe the experience or outcome of every participant.

The confidence intervals for both comparisons lie below zero and approach zero at their upper ends. The p-values are unadjusted and are 0.04 and 0.036. These summaries speak to statistical uncertainty under the analyses represented by the posted results. They do not establish the clinical importance of the differences. The registry record does not report a threshold for a clinically meaningful change, and it does not report a multiplicity procedure.

The endpoint concerns a short stated follow-up interval. The result does not establish performance over longer periods, in other populations, or under other wear patterns. The record identifies current soft contact lens wearers with myopia and daily disposable use as the study context, but it does not give detailed participant characteristics or adherence information. The degree to which the results apply beyond the enrolled participants and study procedures cannot be determined from the registry record alone.

Nor do the averages establish that every participant experienced the same change. The standard deviations describe variation, but the registry record does not provide participant-level distributions. The posted safety counts are zero for serious events, other adverse events, and deaths in each arm; those registry counts do not establish that risks are absent or identical.

In short, the record presents numerical comparisons of average change and associated unadjusted statistical summaries. It does not provide the clinical threshold, full analysis plan, missing-data details, or extended follow-up information needed to support broader conclusions about importance, robustness, or longer-term outcomes. The results should be read within the measured endpoint, groups, and timeframe that the registry reports.

16. Why This Trial Matters Statistically

This study illustrates how a randomized comparison can be reported using a continuous outcome and multiple comparator groups. The primary measure is mean change in logMAR visual acuity, and the registry posts an arm mean, dispersion measure, and between-arm comparison for each comparator against kalifilcon A. That structure makes it possible to distinguish the observed average change within an arm from the estimated difference between arms.

Statistically, the estimates are close to zero in the logMAR scale, and their confidence intervals approach zero at one end. The unadjusted p-values are below 0.05, but the record does not report a multiplicity procedure or a clinically meaningful threshold. These features show why significance testing alone is not a complete interpretation: the estimated magnitude, uncertainty, comparison structure, and clinical context all matter.

The record also offers an example of the gap between a registry result and a full statistical report. It posts summary outcomes but no analysis entries, and it does not describe the original sample-size justification, missing-data methods, analysis populations, or model. Readers can describe the posted estimates, but cannot verify important design and analysis decisions from this record alone.

The sample-size illustrations further demonstrate that planned sample sizes depend on the effect targeted. Smaller target effects require more participants under the stated planning assumptions. These calculations are useful for understanding design tradeoffs, but they are not evidence of the trial’s original planning or of the probability that its observed result is correct.

Finally, the adverse-event counts are simple reported counts rather than a detailed safety analysis. Separating descriptive counts from inferential conclusions is important when interpreting sparse events. The trial is statistically informative as a case in reading group means, intervals, unadjusted comparisons, and registry-level reporting limitations without extending beyond the data and design details recorded.

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 limitations unresolved. Although the study is randomized and single-masked, it does not describe the randomization sequence, allocation concealment, who was masked, or how masking was maintained. The record does not provide detailed eligibility criteria or baseline characteristics, which limits assessment of how the enrolled groups were composed and how broadly the results might apply.

The endpoint is reported at baseline and 2 Week Follow up, but the record does not describe the visual-acuity assessment procedure, adherence to lens wear, or handling of departures from assigned use. It does not provide participant flow, numbers with missing endpoint measurements, or reasons for missingness. The absence of these details prevents assessment of whether the posted outcome counts represent all randomized participants or a selected analysis population.

The record contains no posted analysis entries. It does not report the statistical model, covariate adjustment, interval method, prespecified multiplicity approach, or sensitivity analyses. The sponsor’s original sample-size justification and any interim analyses are not reported in the registry record. The separate planning illustration is based on observed effects and cannot substitute for those missing design details.

The reported comparisons use unadjusted p-values, and no clinical importance threshold is stated. The follow-up timeframe is short as described in the primary endpoint, and no longer-term primary outcome is listed. Safety information consists of the posted event counts; definitions, exposure-time summaries, and detailed event descriptions are not reported in the registry record. These limitations do not change the numerical summaries, but they constrain how confidently those summaries can be interpreted and generalized.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Product Performance of a New Silicone Hydrogel Contact Lens — NCT04901897.
• Registry record last updated 2021-07-08; status last verified 2021-06.
• Results first posted 2021-07-08.
• 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 describes a completed, randomized, single-masked, parallel study of kalifilcon A, delefilcon A, and senofilcon A daily disposable contact lenses in current soft contact lens wearers with myopia. Total enrollment was 805. The primary endpoint was mean change in logMAR contact lens visual acuity from baseline to 2 Week Follow up.

Posted mean changes were -0.056 for kalifilcon A and -0.069 for each comparator. The mean-difference estimates versus kalifilcon A were -0.013 for both comparisons, with unadjusted p-values of 0.04 and 0.036. Serious adverse events, other adverse events, and deaths were reported as zero in every arm.

The registry record does not report the trial’s statistical analysis plan, original sample-size justification, missing-data methods, analysis populations, or multiplicity strategy. The results are therefore best understood as posted group summaries and comparisons for the stated endpoint and timeframe.