Clinical Evaluation Of Two Daily Disposable Contact Lenses And A Monthly Replacement Lens: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Evaluation Of Two Daily Disposable Contact Lenses And A Monthly Replacement Lens (NCT01151371), a randomized na study. The primary outcome is Overall Comfort Narafilcon B v. Nelfilcon A.

2. Clinical Question

3. Trial Design

The registry describes a randomized, single-masked, parallel-group clinical trial. It lists an enrollment of 452 and a completed status. The listed start date is 2010-02-01, and the primary completion date is 2010-04-01. The record does not report who was masked, how the random sequence was generated, or how allocation was concealed.

Three lens regimens appear in the intervention descriptions: narafilcon B daily disposable for 4 weeks, nelfilcon A daily disposable for 1 week, and lotrafilcon B worn daily with monthly replacement for 4 weeks. The registered objective was to compare the clinical performance of silicone hydrogel daily-disposable lenses, conventional hydrogel daily-disposable lenses, and silicone hydrogel monthly replacement lenses. The posted primary outcome, however, is a one-week comfort comparison between narafilcon B and nelfilcon A.

For the primary outcome, the posted group summaries include 147 participants for narafilcon B and 148 for nelfilcon A. Those outcome denominators need not represent the entire enrolled population: the registry record does not explain the difference between enrollment and the numbers reported for this outcome. It also does not report whether the primary analysis followed an intention-to-treat population, a per-protocol population, or another analysis population.

The registry lists eight secondary outcomes, covering corneal staining and subjective ratings of lens handling and comfort across comparisons involving narafilcon B, nelfilcon A, and lotrafilcon B. Detailed secondary results are posted for only some of those outcomes. The registry record does not report a full protocol, a detailed statistical analysis plan, or the original rationale for the trial’s design and enrollment.

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 Overall Comfort Narafilcon B v. Nelfilcon A, measured over After 1 week.

The primary endpoint is mean overall comfort after 1 week, measured in units on a scale using the CLUE questionnaire. The registry describes CLUE as a validated patient-reported outcomes questionnaire for assessing contact-lens experience, including comfort, vision, handling, and packaging. Its stated target population is contact-lens wearers in the US ages 18-65.

The endpoint focuses on the wearer’s reported experience rather than an examination finding or a measure of lens replacement behavior. The registry describes CLUE scores as normally distributed, with a population average score of 60 and a standard deviation of 20. Higher scores indicate a more favorable or positive response. These scale properties help give the score context, but they do not establish what size of difference would matter to participants; a threshold for a clinically important difference is not reported in the registry record.

A mean is a way to summarize the average score in a group. Comparing group means offers a concise description of how reported comfort differed between the two lens groups at the specified assessment time. The endpoint is relevant to the registered comparison because comfort is one of the patient-experience attributes the questionnaire is designed to assess. The record does not describe how questionnaires were administered, how incomplete responses were handled, or whether other CLUE attributes were part of the primary analysis.

7. Results Posted in the Registry

• Nelfilcon A: mean 53.75 versus 68.32 on control; difference -14.57 (95% CI -19.88 to -9.26), standardized effect d = -0.63; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Signs of Inferior Corneal Staining Narafilcon B v. Nelfilcon A

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Nelfilcon A: mean 0.31 versus 0.13 on control; difference 0.18 (95% CI 0.07 to 0.29), standardized effect d = 0.38; z-test p = 0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Nelfilcon A than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Subjective Rating of Overall Ease of Lens Handling Narafilcon B v Nelfilcon A

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Nelfilcon A: mean 60.76 versus 64.05 on control; difference -3.29 (95% CI -8.35 to 1.77), standardized effect d = -0.15; z-test p = 0.203.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Nelfilcon A and the control. The interval gives the range of effects that remain compatible with the data.

Subjective Rating of End of Day Comfort Narafilcon B v. Nelfilcon A

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Nelfilcon A: mean 2.81 versus 3.69 on control; difference -0.88 (95% CI -1.18 to -0.58), standardized effect d = -0.66; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Nelfilcon A than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The registry lists secondary comparisons involving corneal staining, lens handling, initial comfort, and end-of-day comfort. These outcomes broaden the scope beyond the primary one-week overall comfort score: some concern signs observed on the eye, while others concern participants’ subjective experience. The registry lists eight secondary outcomes, but detailed numerical results are posted for only some. Results for secondary outcomes not detailed in the record are not reported in the registry record.

Across the detailed secondary results, the directions and apparent strength of differences are not uniform. Some posted measures show a mean difference whose interval excludes zero, while another has an interval that includes zero. That broad pattern complements, but does not replace, the primary result: it suggests that the registry’s different measures do not all provide the same degree of evidence for a group difference. The secondary outcomes also use different scales, so their numerical estimates should not be compared as if they measured the same quantity.

Each secondary result is unadjusted. In general, when many outcomes or comparisons are tested, the chance of obtaining at least one apparently notable result by chance increases. Adjustment methods can address some forms of this multiplicity, but the registry record does not report a multiplicity strategy. Consequently, isolated secondary p-values carry less weight than a prespecified primary result interpreted with its estimated size and uncertainty. This is particularly important when the registry does not report the analysis plan or which secondary comparisons were prespecified.

The secondary findings are best treated as supportive or exploratory information, not as a substitute for the primary endpoint. The record does not report whether all listed secondary measures were collected at the same visit, how missing secondary data were handled, or whether any outcomes were prioritized. Such details are needed to assess the strength and coherence of the secondary evidence more fully.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Signs of Inferior Corneal Staining Narafilcon B v. Nelfilcon A
• Subjective Rating of Overall Ease of Lens Handling Narafilcon B v Nelfilcon A
• Subjective Rating of End of Day Comfort Narafilcon B v. Nelfilcon A
• Subjective Rating of Initial Comfort Narafilcon B v. Nelfilcon A
• Signs of Inferior Corneal Staining Narafilcon B v. Lotrafilcon B
• Subjective Rating of Overall Ease of Lens Handling Narafilcon B v. Lotrafilcon B
• Subjective Rating of End of Day Comfort Narafilcon B v. Lotrafilcon B
• Subjective Rating of Initial Comfort Narafilcon B v. Lotrafilcon B

9. Statistical Interpretation

10. Statistical Methods Explained

The primary result compares group means for a continuous outcome. A continuous score can take values across a measurement scale, and its mean summarizes the average observed score within a group. The registry reports each group’s mean and standard deviation, along with a mean difference. The difference is oriented as nelfilcon A minus narafilcon B: the nelfilcon A mean is lower, so the reported difference is negative. This direction should be kept in mind when interpreting both the estimate and its interval.

What do the mean and standard deviation describe?

The mean describes the group’s average score; it does not describe every participant’s experience. The standard deviation describes variability among individual scores around the group mean. A larger standard deviation indicates more spread in scores, while a smaller one indicates that scores are more concentrated around the mean. It is not the same as the standard error, which concerns uncertainty in an estimated mean. The primary outcome reports standard deviations of 22.82 for narafilcon B and 23.71 for nelfilcon A.

For the primary comparison, the reported mean difference is -14.57 and the posted interval runs from -19.88 to -9.26. The interval presents uncertainty around the estimated difference, subject to the statistical method and assumptions used. The registry record does not identify the method or confidence level. General interpretation: an interval that stays on one side of zero is consistent with a difference in that direction under the interval procedure, while an interval that includes zero would also be compatible with no difference under that procedure. This does not by itself show whether a difference is meaningful to participants.

What does the p-value add?

The primary unadjusted p-value is <0.001. In general, a p-value evaluates how unusual data at least as extreme as those observed would be if a specified null hypothesis and the test assumptions held. It is not an effect-size measure and should not replace consideration of the estimated difference and its uncertainty. The registry record does not report the particular test, its assumptions, or a prespecified adjustment for multiple comparisons. The word “unadjusted” matters because the result is not presented as corrected for testing multiple outcomes or comparisons.

The posted primary summaries are descriptive group statistics and a comparison. They do not reveal whether the investigators used an adjusted model, how any covariates were chosen, or how missing outcome data were handled. Those analysis details are not reported in the registry record. As a result, the posted record supports interpretation of the reported contrast but not a reconstruction of the full analysis.

Why does over-dispersion matter in general?

Over-dispersion is a general issue for count outcomes when observed variability exceeds what a chosen statistical model expects. It can make standard errors too small and intervals too narrow if the model does not account for the extra variability. It is not the central issue for this primary continuous comfort score, for which the registry posts group means and standard deviations. The registry record does not report a count-model analysis for the primary endpoint.

Some secondary measures are also continuous, including the reported mean ratings and the corneal-staining measure. Their measurement scales and directions should be considered individually; a numerical difference on one scale is not directly interchangeable with a difference on another. For the end-of-day comfort secondary result, the registry reports standard errors for the group summaries rather than standard deviations. These describe uncertainty in the group means, not the spread of individual observations. The record does not provide a detailed explanation of the scales or analysis methods for each secondary outcome.

What can randomization establish?

In general, random allocation is intended to make treatment groups comparable with respect to measured and unmeasured characteristics on average, subject to proper implementation and chance variation. The registry identifies allocation as randomized, but it does not report the sequence-generation or concealment procedures. Nor does the posted record establish how adherence, follow-up, or missing scores were addressed. Those omissions limit assessment of whether the reported comparison reflects the planned randomized contrast without important bias.

The planning illustrations use the observed effect as a reference and show participant requirements under stated hypothetical assumptions. They are not a record of the trial’s own design calculations. The registry’s original sample-size justification and its assumptions are not reported. The illustrations are therefore useful for understanding how hypothetical future sample sizes vary with the target effect, but they cannot establish what the original investigators planned or what precision they intended to achieve.

11. Confidence Intervals and Precision

The primary mean difference is -14.57, with posted bounds from -19.88 to -9.26. These bounds indicate that the point estimate is not the only plausible value under the interval procedure; they express uncertainty around the group contrast. The interval lies on the negative side of zero for the stated direction, nelfilcon A minus narafilcon B. The registry record does not report the confidence level or the method used to calculate the interval, so those details should not be assumed.

In general, a confidence interval combines information about an estimate and its uncertainty. A narrower interval indicates greater precision under the method used, while a wider interval indicates more uncertainty. Precision is distinct from practical importance: an interval can be narrow without answering whether an effect matters to participants, and a point estimate alone does not convey uncertainty. The record does not report a threshold for a clinically important difference in CLUE comfort scores, so the interval cannot be classified against such a threshold from the registry information.

The primary group summaries include 147 participants for narafilcon B and 148 for nelfilcon A. The standard deviations, 22.82 and 23.71 respectively, describe variability in individual scores. The registry does not explain whether these denominators include everyone assigned to each group or only participants with usable outcome data. It also does not report missing-data methods or the analysis population, which are relevant to judging the precision and potential representativeness of the posted estimate.

The primary p-value is <0.001, but a small p-value is not a substitute for an interval or an assessment of practical importance. Together, the estimate, interval, and group variability describe the result more fully than any one statistic alone. Their interpretation remains conditional on the unreported analysis procedures.

12. 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 planning figures are stated as participants per arm, not as total events. They illustrate hypothetical sample sizes for a two-group comparison using the observed effect as a reference. The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each scenario targets a stated fraction of the observed effect. The trial’s own original design assumptions and sample-size justification are not reported in the registry record.

The 80% power column describes the number of participants per arm in a hypothetical design that would have an 80% probability of detecting the specified effect under the planning assumptions, if that effect and the assumptions were correct. The 90% power column describes the corresponding hypothetical design with a 90% probability. These are prospective design concepts, not probabilities that this completed trial’s result is correct.

Planning for 100% of the observed effect uses the full observed effect as the target. Planning for 75% or 50% of the observed effect uses smaller target differences. Smaller effects are harder to distinguish from random variation under otherwise similar assumptions, so the planning illustrations require more participants per arm as the target effect becomes smaller. The figures are illustrations for planning, not observed power.

The planning scenarios are based on the posted effect estimate, which is itself subject to uncertainty. If the true effect in a future study differs from the observed estimate, the illustrated participant requirements may not achieve the stated power. The registry record does not report the original assumptions that determined enrollment for this trial. The planning figures therefore should not be used to infer the rationale for the trial’s enrollment or to claim that its design had a particular power.

13. 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 = -14.570; pooled standard deviation σ = 23.271.
2. n = 2 × (1.96 + 0.842)² × 23.271² / -14.570² = 40.0, rounded up to 41 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 <- -14.57                      # observed difference in means
sigma <- 23.2707739112827                     # 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(1151371)
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 = 41 (80% power), 54 (90% power)
 75% of observed effect: n per arm = 72 (80% power), 96 (90% power)
 50% of observed effect: n per arm = 161 (80% power), 215 (90% power)
power.t.test: 41 
Simulated power at n = 41 per arm: 0.803 (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.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple secondary outcomes and comparisons, in addition to a primary outcome. Testing multiple outcomes creates a multiplicity concern: in general, the more statistical questions examined, the greater the chance that at least one result will appear notable even when there is no corresponding underlying effect. A prespecified testing hierarchy or an adjustment procedure can help control this issue, but neither is described in the registry record. The posted secondary p-values are unadjusted, so they should not be read as if they accounted for all the comparisons conducted.

The registry record does not report the trial’s statistical analysis plan, a multiplicity strategy, or whether interim analyses were performed. It also does not report the method used to select the primary analysis or whether the posted analysis followed a prespecified plan. Without those details, it is not possible to determine from the record how outcome selection and repeated testing were handled.

Missing-data handling is also not reported in the registry record. The posted primary outcome summaries include 147 participants for narafilcon B and 148 for nelfilcon A, while the registry lists an enrollment of 452. The record does not explain which participants contributed to each analysis, whether anyone lacked an outcome measurement, or how any missing observations were treated. It does not identify an intention-to-treat or per-protocol analysis population.

These omissions do not show that the trial had a particular problem; they limit what can be evaluated from the registry record. In general, missing outcomes can affect both the representativeness of a group mean and the validity of a between-group comparison, depending on why data are missing and how the analysis handles them. A complete assessment would require details of outcome availability, analysis populations, and prespecified methods, which are not reported in the registry record.

15. Safety Results

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

Other (non-serious) adverse events

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

The registry reports zero serious adverse events affecting participants at risk in each listed group: Narafilcon B 4 Weeks, Nelfilcon A 1 Week, and Lotrafilcon B 4 Weeks. It also reports zero other adverse events affecting participants at risk in each of those groups. The at-risk counts are 149 for Narafilcon B 4 Weeks, 150 for Nelfilcon A 1 Week, and 153 for Lotrafilcon B 4 Weeks. These are the safety denominators reported for the respective groups.

These figures mean that the registry records no serious or other adverse events as affecting participants in the listed groups during the reported safety record. They do not establish that no symptoms or events occurred outside the registry’s adverse-event categories, nor do they describe how events were collected, monitored, or classified. The deaths field is not populated; deaths are not reported in the registry record.

Zero recorded events should be interpreted in light of the study record and its follow-up, not as proof that a risk is absent. The registry does not report additional detail about event definitions, timing, severity beyond the serious-versus-other categories, or individual event narratives. The listed safety counts are distinct from the outcome denominators for the primary comfort analysis.

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

The posted primary result describes a difference in reported overall comfort after 1 week. Narafilcon B had a mean score of 68.32, compared with 53.75 for nelfilcon A; the mean difference was -14.57 when expressed as nelfilcon A minus narafilcon B. Higher CLUE scores indicate a more favorable response, so the group means are in the direction of more favorable reported comfort for narafilcon B at that assessment.

This result does not show that every participant preferred one lens, because group averages do not describe every individual response. Nor does the result establish how a particular person would experience either lens. It concerns a specified questionnaire measure and a one-week assessment, not every aspect of lens use or longer-term experience.

The trial included lotrafilcon B, but the posted primary comparison is between narafilcon B and nelfilcon A. The primary result therefore does not establish how narafilcon B or nelfilcon A compares with lotrafilcon B on this endpoint. The registry describes different lens and replacement schedules, so the comparison is between the regimens as described, not a controlled isolation of one lens characteristic.

The statistical result also does not determine whether the difference is important to participants. The registry record does not report a threshold for a clinically important difference in CLUE scores. It does not provide the full analysis plan, missing-data approach, or population details needed to evaluate all potential sources of uncertainty. The result should therefore be understood as a posted group-level estimate with the accompanying uncertainty, rather than as a complete account of the trial’s evidence.

Finally, the recorded adverse-event counts are not a guarantee of safety in all settings or over longer use. They describe the events entered in the registry for the listed groups and do not replace detailed safety information that is not reported in the registry record. The findings speak to this trial’s recorded outcomes and follow-up, not to every population, use pattern, or outcome of interest.

17. Why This Trial Matters Statistically

This trial illustrates why a patient-reported endpoint can add information that is not contained in an examination finding alone. The primary measure is a questionnaire score about overall comfort, while listed secondary outcomes include both subjective ratings and a sign of inferior corneal staining. These measures address different aspects of contact-lens experience and should not be treated as interchangeable.

It also illustrates the value of reading an estimate together with its uncertainty. A mean difference describes the direction and size of the observed group contrast, while an interval communicates the uncertainty around that estimate under the method used. A p-value provides a different summary and does not state whether the difference is important to participants. Keeping these roles separate supports a more balanced interpretation than focusing on a single statistical marker.

The registry also shows why multiplicity and transparency matter. Several outcomes and comparisons are listed, but the record does not report a multiplicity strategy or a detailed analysis plan. When multiple results are considered, unadjusted secondary findings require more caution than a single clearly prespecified primary question. The absence of details does not prove that a suitable plan was not used; it means the registry record cannot establish how these issues were handled.

Finally, the sample-size illustrations demonstrate how planning requirements depend on the effect a future study aims to detect. Smaller target effects require larger hypothetical samples under the stated assumptions. These illustrations are separate from the trial’s original design rationale, which is not reported in the registry record, and they are not a measure of the completed trial’s observed power.

18. 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 gives a limited account of the design and analysis. It identifies randomization, single masking, and a parallel model, but does not report who was masked, how randomization was generated or concealed, or whether group assignments were implemented as planned. These details are important for evaluating the protections against bias.

The primary outcome comparison is between two lens regimens, while a third regimen is also included in the trial. The posted primary result does not compare all three regimens. The lens groups are described with different replacement schedules and durations, so the primary result cannot isolate the contribution of lens material from other differences in the regimen.

The registry does not report a detailed analysis plan, the original sample-size justification, analysis populations, missing-data methods, or any interim analyses. The outcome denominators are reported, but the record does not explain their relationship to enrollment or specify whether all randomized participants contributed to the primary analysis. The confidence level and interval method are also not reported in the registry record.

Interpretation of the patient-reported result is limited by the absence of a reported clinically important difference threshold. The record describes the CLUE scale and its direction, but does not state what difference would be meaningful to participants. The registry lists eight secondary outcomes, yet detailed numerical results are posted for only some; the remaining results are not reported in the registry record. It also does not describe the multiplicity approach or give detailed event-collection methods for the safety summaries.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Clinical Evaluation Of Two Daily Disposable Contact Lenses And A Monthly Replacement Lens — NCT01151371.
• Registry record last updated 2018-06-19; status last verified 2017-08.
• Results first posted 2011-12-19.
• 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.

22. Record Summary

The registry describes a completed, randomized, single-masked, parallel-group study of three contact-lens regimens for myopia, with enrollment of 452. The primary outcome is mean overall CLUE comfort after 1 week for narafilcon B compared with nelfilcon A. The posted means are 68.32 and 53.75, respectively, with a mean difference of -14.57 for nelfilcon A minus narafilcon B and an unadjusted p-value of <0.001.

The registry lists eight secondary outcomes and reports zero serious and zero other adverse events affecting participants in each listed safety group. Important analysis details—including the original sample-size rationale, missing-data methods, analysis populations, and multiplicity plan—are not reported in the registry record. The result is a one-week group comparison and does not address every lens comparison or outcome listed for the trial.