Clinical Comparison of Two Daily Wear Frequent Replacement Silicone Hydrogel Soft Contact Lenses: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Comparison of Two Daily Wear Frequent Replacement Silicone Hydrogel Soft Contact Lenses (NCT04532099), a randomized na study. The primary outcome is Distance Visual Acuity (VA) (Part A).

2. Clinical Question

This is a question about a measured visual-acuity outcome under the study conditions, not a general comparison of all benefits, risks, or uses of the lenses. The record gives a mean and standard deviation for each Part A lens and a mean-difference estimate with an interval and an unadjusted p-value. Those summaries describe the posted endpoint, but they do not establish how each individual experienced vision or whether the lenses were equivalent under a prespecified clinical criterion. No such equivalence margin or decision rule is reported in the registry record.

3. Trial Design

The registry describes a randomized, double-masked, crossover study with an enrollment of 132. The study was marked completed. It began on 2020-09-09, and primary completion was recorded as 2021-05-04. The registry lists the phase as not applicable. The sponsor was Alcon Research.

In Part A, participants wore lehfilcon A and senofilcon A lenses in the sequence assigned by randomization. One arm description specifies lehfilcon A first and AOHP next; the other specifies AOHP first and lehfilcon A next. Each product was worn bilaterally for approximately 30 days, with a scheduled visit at approximately Day 15 of each wear period. Lenses were removed nightly for cleaning and disinfection. The record also names a hydrogen peroxide-based cleaning and disinfecting solution among the interventions.

Part B involved comfilcon A lenses, identified as Biofinity. The description specifies bilateral wear for approximately 30 days and a scheduled visit at approximately Day 15. It also names CLEAR CARE contact lens solution for nightly cleaning and disinfection. The primary endpoint, however, is explicitly designated for Part A only; the posted result does not compare Part B with the Part A lenses.

A crossover design means that a participant receives more than one study condition in sequence, so each participant can contribute observations under different conditions. As a general statistical consideration, the analysis may need to account for the paired nature of measurements and for sequence or period effects. The registry record does not report the analysis model or explain how these considerations were handled. Details about washout periods, adherence, allocation concealment, or the masking procedures are not reported in the registry record.

The reported primary-endpoint groups contain 66 and 65 observations, respectively. These are the group counts attached to the posted endpoint results; the record does not provide a flow account explaining how enrollment relates to those analysis counts. It also does not report further information about withdrawals or missing endpoint measurements.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

First Wear Period (30 Days)

Reasons for not completing this period:

Second Wear Period (30 Days)

Analysis population for the primary outcome, as defined in the registry: Safety Analysis Set

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.

Population: Safety Analysis Set: All subjects/eyes exposed to any study lenses evaluated in this study.

6. Primary Endpoint

The registry lists the primary outcome as Distance Visual Acuity (VA) (Part A), measured over Day 30, each study lens type.

The primary endpoint was distance visual acuity measured with the study lens in place at Day 30 for each study lens type in Part A. The measure was recorded in logMAR, with the mean and standard deviation reported for each arm. The registry explains that each eye was assessed separately using logarithmic Minimum Angle of Resolution charts. It notes that 0.0 logMAR corresponds to 20/20 Snellen acuity and that a negative value denotes acuity better than 20/20.

Visual acuity is a continuous measurement: individual observations can take a range of values, and a group mean summarizes their central tendency. It is used to describe distance acuity while the assigned study lens was in place. Reporting the standard deviation alongside the mean gives an indication of variation among the measurements, although it does not show the full distribution or the experience of every participant.

The registry names Day 30 as the measurement timeframe and says the primary endpoint was prespecified for Part A only. It also states that no formal hypothesis testing was predefined for this endpoint. Thus, the endpoint description supports a comparison of the observed summary values, but the record does not specify a formal threshold for deciding that one lens is clinically better, worse, or equivalent. Other details of measurement implementation, such as chart protocol or assessor procedures, are not reported in the registry record.

7. Results Posted in the Registry

• AOHP (Part A): mean -0.12 versus -0.12 on control; difference 0.00 (95% CI -0.03 to 0.03), standardized effect d = 0.00; z-test p = 1.000.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary result is a comparison of means for a continuous outcome. A mean gives the arithmetic center of the recorded measurements, while the standard deviation describes their spread around that center. These summaries are useful for a concise description, but they do not show whether the data are symmetric, whether there are outliers, or how measurements vary across individuals. The registry reports the means and standard deviations for each Part A lens.

The estimated mean difference is listed as 0.0. A difference is formed by contrasting the two group means according to a specified order; here, the posted estimate indicates no difference at the reported precision. The exact conventions for contrast direction and the full model are not described in the registry record. The arm means are each -0.12 logMAR, with a standard deviation of 0.09 in each arm.

The comparison lists an interval from -0.031 to 0.031, along with an unadjusted p-value of 1.0. The interval is a measure of statistical uncertainty around the estimated difference, conditional on the calculation's assumptions. An interval is not a range containing all individual outcomes, and it is not a probability statement about the true effect. Since the registry says no formal hypothesis testing was predefined, these inferential quantities should be read cautiously. The record does not state whether the interval and p-value were part of the sponsor's planned analysis or describe a model for deriving them.

General explanation: A p-value is calculated under a null hypothesis and a statistical model. It describes how incompatible the observed data are with that null model, subject to the model assumptions. It is not the probability that the null hypothesis is true, nor a direct measure of clinical importance. A large p-value does not prove that two treatments are equivalent; an equivalence conclusion ordinarily requires a prespecified margin and an analysis designed to evaluate that margin. Such a margin is not reported in the registry record.

The crossover allocation matters for statistical interpretation. In a crossover study, participants receive more than one condition, often at different periods. As a general method principle, a paired analysis can account for the fact that measurements from the same participant may be correlated. Accounting for that correlation may make an estimate more or less precise than a comparison that ignores it, depending on the data and assumptions. Period effects, sequence effects, and carryover are also general considerations in crossover designs. The registry record does not report whether these effects were assessed or how they entered the analysis. It is therefore not possible to infer the actual analytical method from the design label alone.

The endpoint was assessed separately for each eye. As a general statistical consideration, two eyes belonging to one person may have correlated measurements, so an analysis may need to account for clustering within a person. The posted summary does not state whether eyes were analyzed independently, combined in some way, or handled through a model that accounts for correlation. The registry record also does not report the number of eye-level observations used for each summary or the handling of any unavailable eye measurements.

The posted primary-endpoint population is the Safety Analysis Set. That label identifies the analysis population named in the record, but the inclusion criteria for that set are not reported in the registry record. No separate intention-to-treat or per-protocol primary analysis is posted in the registry record described by the registry record. The relationship between the enrollment figure and the endpoint counts is not explained, and reasons for any difference are not reported.

Multiplicity concerns arise when a study evaluates several outcomes, time points, or comparisons and makes inferential claims across them. As a general statistical principle, repeated testing can increase the chance of finding a nominally unusual result by chance unless the analysis plan addresses that issue. The record reports one outcome measure and no posted secondary outcomes, but it does not report the full protocol-level set of planned tests or any adjustment strategy. Since no formal hypothesis testing was predefined for the primary endpoint, there is no reported multiplicity-adjusted primary test to interpret.

The record does not report a sample-size justification, a target power, or the assumptions used to plan enrollment. Any sample-size figures elsewhere should be understood as planning illustrations based on stated assumptions, not as observed power or a description of the trial's original design rationale. In general, a planning calculation depends on the target effect, variability, significance level, allocation, and analysis method. The registry record does not provide a trial-specific rationale for those choices.

Missing-data methods are likewise not reported in the registry record. General explanation: missing outcome data can affect both the estimate and its uncertainty, particularly when the chance of missingness is related to the outcome or treatment experience. The analysis approach therefore matters, but it should not be inferred from the summary statistics. The record does not state whether imputation, a complete-case approach, or another method was used.

10. Confidence Intervals and Precision

The posted mean difference for Day 30 distance visual acuity is 0.0, and the comparison includes an interval from -0.031 to 0.031. The interval conveys uncertainty around the estimated average difference, under the calculation's assumptions. It is not a range of individual visual-acuity values. Because the registry does not describe the derivation or model, the interval's dependence on crossover pairing, period effects, and eye-level correlation cannot be assessed from the record.

The estimate is centered on no difference at the displayed precision, but an estimate alone is not a guarantee of precision. The interval is the more direct summary of statistical uncertainty. Determining whether that uncertainty is small enough for a clinical conclusion would require a prespecified threshold for a meaningful difference. A threshold of that kind is not reported in the registry record. Therefore, the interval cannot be used to declare equivalence or noninferiority based on the record alone.

Precision also differs from consistency across participants. The standard deviation of 0.09 in each arm describes variability in measurements, while the interval for the mean difference describes uncertainty about the contrast. Neither summary shows the full distribution, individual changes across lens periods, or the proportion of participants with particular outcomes. The record does not provide those details.

In a crossover design, precision can depend on how strongly measurements within the same participant are related. As a general statistical point, paired information can improve precision when within-person measurements are positively related, but the actual gain depends on the observed correlation and the analysis. That correlation is not reported in the registry record. The posted interval should therefore be read as the interval associated with the reported comparison, without assuming a particular paired or unpaired method.

11. Multiplicity, Missing Data and Analysis Populations

The registry states that no formal hypothesis testing was predefined for the primary endpoint. It does not report a prespecified testing hierarchy, an adjustment for multiple comparisons, or a complete list of all planned analyses. The record posts one outcome measure and no secondary outcomes, but this does not establish what analyses may have been planned outside the posted results. Multiplicity procedures are not reported in the registry record.

As a general statistical explanation, multiplicity arises when several outcomes, time points, or comparisons are assessed. Without an appropriate plan, interpreting a collection of p-values as if only one test had been conducted can overstate the strength of evidence. That general concern does not mean that an unreported analysis occurred; it means the registry record does not permit assessment of the broader testing context.

The stated primary analysis population is the Safety Analysis Set. The record does not define membership in that set, provide a flow of participants through each lens period, or explain the relationship between enrollment and the two endpoint group counts. Reasons for missing endpoint data, if any, are not reported in the registry record.

Missing-data handling is also not described. The registry does not state whether the posted summaries use all available measurements, a particular imputation method, or another approach. As a general principle, the impact of missing data depends on how much is missing and why it is missing; those details are needed to judge potential bias. Neither the amount nor the assumed mechanism is reported in the registry record.

The record does not report interim analyses, stopping rules, a sample-size justification, or the detailed statistical analysis plan. These omissions limit assessment of how the posted comparison relates to the original design and planned analysis. They do not alter the descriptive fact that the two reported means are -0.12 logMAR.

12. 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 adverse-event summaries list zero serious adverse events, zero other adverse events, and zero deaths in each displayed group. The record gives separate groups for pretreatment, ocular outcomes, and nonocular outcomes, and the at-risk counts differ across those entries. These figures describe the posted registry summaries; they should not be combined across entries or treated as a single common observation period.

The ocular group counts include 132 at risk for LID018869 and 130 for AOHP, while the nonocular group counts are 66 and 65, respectively. The record does not explain the unit represented by each at-risk count or how repeated exposure and crossover periods affect those denominators. A participant and an eye are not interchangeable units, and the registry does not provide enough detail to infer a common denominator across adverse-event categories.

Zero events in a posted group means that no events of that category were recorded in that group summary. It does not establish that the risk is absent, particularly when the observation period and ascertainment details are not available. The record does not provide event-level narratives or a list of serious-event terms; no top serious-event terms are listed. These summaries should be read as descriptive safety reporting, not as a formal comparison of risk between lenses.

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

The result supports a narrow descriptive statement: the posted Day 30 mean distance visual acuity was -0.12 logMAR for each Part A lens, with a standard deviation of 0.09 in each arm. The listed mean difference is 0.0. These statistics summarize the recorded endpoint in the analysis population named by the registry.

They do not show that the lenses produce identical measurements for every person, because group means can match while individual observations vary. They also do not establish that the lenses are equivalent, noninferior, or interchangeable. Such conclusions depend on a prespecified clinical margin and an analysis designed to evaluate it; neither is reported in the registry record. The reported unadjusted p-value does not replace that requirement, especially since formal hypothesis testing was not predefined for the primary endpoint.

The finding is specific to distance visual acuity measured with the study lenses in place at Day 30 in Part A. It does not answer questions about other outcomes, longer-term use, different wear conditions, or Part B. The registry lists comfilcon A as a Part B intervention, but the primary endpoint is designated for Part A, and no comparative primary result for Part B is posted in the record.

The precision of the comparison also depends on analysis details that are not reported, including how the crossover structure and measurements from each eye were handled. The endpoint counts and the Safety Analysis Set label do not explain missingness or analysis eligibility. Consequently, the posted summary should be understood as a limited account of the measured outcome, not as a complete assessment of all design and analysis questions.

Nothing in these figures alone establishes a treatment recommendation. They describe a statistical result from a particular randomized, double-masked study and should not be extended beyond its endpoint and record.

14. Why This Trial Matters Statistically

This trial is statistically instructive because it combines a continuous outcome with a crossover design. The mean and standard deviation provide an accessible summary of distance visual acuity, while the crossover structure raises questions about within-person comparisons, period effects, sequence, and correlation. Those design features matter because they can affect both the estimated contrast and its precision.

The posted means are the same at the displayed precision, and the registry also supplies an interval and an unadjusted p-value. At the same time, the registry explicitly says no formal hypothesis test was predefined. This illustrates why a numerical p-value should not be separated from the design and analysis plan. A result can be described without treating it as a prespecified confirmatory test or as proof of equivalence.

The record also highlights the distinction between a summary estimate and a clinical decision threshold. An observed mean difference of 0.0 does not itself define what difference would matter clinically. Without a reported equivalence or noninferiority margin, statistical similarity at the displayed precision cannot answer that separate question.

Finally, the study reports visual acuity by eye, but the analysis details for within-person and within-eye relationships are not stated. This makes the record a useful reminder that the apparent simplicity of a mean comparison can conceal important choices about the unit of analysis and dependence among observations. Transparent reporting of those choices would make the precision and interpretation easier to assess.

15. 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 details unclear. It does not describe the statistical model used for the crossover comparison, including whether the pairing of measurements, treatment sequence, period, or possible carryover effects were considered. It also does not state how measurements from the two eyes were handled in the analysis.

The primary endpoint is assigned to the Safety Analysis Set, but the record does not define that set or explain how participants entered the endpoint analysis. The posted endpoint counts are 66 for LID018869 and 65 for AOHP, while the registry enrollment is 132. A participant flow, reasons for missing measurements, and the missing-data method are not reported in the registry record.

The record states that formal hypothesis testing was not predefined for the primary endpoint, yet an unadjusted p-value and interval are posted. The relationship of those statistics to any sponsor analysis plan is not explained. No clinical equivalence margin, noninferiority margin, or sample-size justification is reported. These omissions constrain formal interpretation of the comparison.

Further limitations include the absence of detailed participant characteristics, eligibility criteria, masking procedures, and assessment procedures in the information. The primary outcome is limited to Day 30 distance visual acuity in Part A. The record does not provide additional primary-endpoint time points or a posted Part B comparison for this outcome. These gaps should be kept distinct from the descriptive result itself: both posted Part A means are -0.12 logMAR.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Clinical Comparison of Two Daily Wear Frequent Replacement Silicone Hydrogel Soft Contact Lenses — NCT04532099.
• Registry record last updated 2022-05-03; status last verified 2021-05.
• Results first posted 2022-05-03.
• 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.

19. Record Summary

The registry describes a randomized, double-masked crossover study of contact lenses for refractive errors or ametropia, with enrollment of 132 and status marked completed. Part A compared lehfilcon A, identified as LID018869, with senofilcon A, identified as AOHP. Part B included comfilcon A, identified as Biofinity, but the primary endpoint was prespecified for Part A only.

The primary endpoint was Day 30 distance visual acuity in logMAR, measured with the study lens in place and summarized by mean and standard deviation. The posted means were -0.12 in both Part A arms, with standard deviations of 0.09. The posted mean difference was 0.0. The registry states that no formal hypothesis testing was predefined for this endpoint.

The record does not report the detailed analysis model, missing-data approach, multiplicity plan, or sample-size justification. Adverse-event summaries list zero serious events, zero other events, and zero deaths in the displayed groups. Those safety figures are descriptive and have different at-risk counts across categories.