Clinical Evaluation of a Daily Wear Monthly Replacement Silicone Hydrogel Lens: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Evaluation of a Daily Wear Monthly Replacement Silicone Hydrogel Lens (NCT04178720), a randomized na study. The primary outcome is Distance VA (logMAR) With Study Lenses - Completed Eyes.

2. Clinical Question

In plain terms, the trial was set up to evaluate visual acuity and safety during daily wear of the two monthly replacement lens types. The endpoint concerns distance vision measured for each eye individually while the study lens was in place. That is a descriptive question about recorded measurements at scheduled visits; the registry's statement that formal hypothesis testing was not planned means the listed endpoint should not be read as a prespecified statistical test of superiority or equivalence. The registry record does not report a numerical result for either group in the registry entries, so the magnitude and precision of any observed visual-acuity difference cannot be assessed from this record alone.

3. Trial Design

The registry describes a completed, randomized, double-masked, parallel-group study with enrollment of 119. Its recorded phase is NA. The study start date is 2020-01-28 and primary completion date is 2020-06-10. Alcon Research is listed as the sponsor. The study summary frames the evaluation as safety and effectiveness of an investigational soft contact lens compared with a commercially available soft contact lens during daily wear with monthly replacement.

The two arm descriptions specify bilateral lens wear during waking hours, removal each night for cleaning and disinfection, and replacement monthly over the 3-month wear period. Each description gives a target of at least approximately 8 hours per day and approximately 5 days per week. The registry labels the arms LID018869 and Biofinity; the latter is described as using Comfilcon A lenses. The interventions list also includes CLEAR CARE, but the record does not explain its role in the study or identify a corresponding arm description.

Randomized allocation means assignment to study groups was intended to be determined by a random process, which can reduce systematic differences at the outset. The registry does not report the sequence-generation method, concealment procedures, allocation ratio, or who was masked. Double masking is the recorded label, but the record does not say which participants or study personnel it refers to or how masking was maintained. These details therefore cannot be assessed.

The primary endpoint visits are listed as dispense, Week 1, Week 2, Month 1, Month 2, and Month 3 follow-up. The study was completed, but completion status does not by itself establish how many participants contributed usable measurements at each visit. Visit-specific counts, withdrawals, and reasons for missing data are not reported in the registry record. The number of analyses is recorded as zero, and the primary outcome description explicitly says formal hypothesis testing was not planned. Further detail on the protocol, sample-size justification, or statistical analysis plan is not reported in the registry record.

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: Of the 119 enrolled, 1 subject was screen failed. This reporting group includes all enrolled and dispensed subjects/eyes (118/236).

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: This analysis population includes all enrolled and dispensed subjects/eyes that completed the study with data at corresponding in-person visit.

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: This analysis population includes all enrolled and dispensed subjects.

6. Primary Endpoint

The registry lists the primary outcome as Distance VA (logMAR) With Study Lenses - Completed Eyes, measured over Dispense, Week 1 follow-up, Week 2 follow-up, Month 1 follow-up, Month 2 follow-up, Month 3 follow-up (at least 4 hours after lens insertion at each follow-up assessment visit).

The primary endpoint is distance visual acuity (VA) in logMAR with study lenses in place, reported as a mean with a standard deviation. VA was assessed separately for each eye using a letter chart at a distance of 6 meters. The measurement was collected in Snellen form and converted to logMAR. The record explains that a logMAR value of 0 corresponds to 20/20 Snellen visual acuity and that a lower logMAR value indicates better visual acuity.

Distance VA is relevant to this study because it records how clearly participants could see a distance target while wearing the assigned study lens. Measuring with the study lenses in place links the endpoint to the lens-wearing condition under evaluation. The listed schedule covers dispense and follow-up visits through Month 3, with each follow-up assessment made at least 4 hours after lens insertion. This timing defines when the registry says the measurement was taken; it does not establish that every participant attended every visit.

A mean describes the average measurement in the analyzed observations, while a standard deviation describes their spread around that average. These summaries can describe the observed distribution but do not, by themselves, establish whether groups differ beyond chance variation. The registry says that no formal hypothesis testing was planned. Numerical means, standard deviations, visit-specific sample sizes, and group contrasts are not reported in the registry record details available for this interpretation. Accordingly, the endpoint definition can be explained, but the observed level of visual acuity and its precision cannot be evaluated from the recorded information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What a continuous outcome summary means. Distance VA in logMAR is a continuous measure. A mean is the arithmetic average of the measurements included in an analysis, and a standard deviation describes how dispersed those measurements are around the mean. The registry lists these as the summary type for the primary endpoint. The mean and standard deviation are descriptive summaries: they do not alone quantify a treatment contrast, account for uncertainty in a contrast, or show whether observed group differences are compatible with chance variation. No numerical primary endpoint summaries appear in the registry entries.

How to interpret the direction of logMAR. The registry gives the scale's interpretation: 0 corresponds to 20/20 Snellen VA, and a lower logMAR value indicates better VA. That direction matters when reading any group means or differences. A smaller value is not worse simply because it is numerically smaller. The record says that Snellen measurements were converted to logMAR, but it does not report further information about conversion procedures, quality checks, or how measurements were aggregated across eyes or participants.

What a confidence interval would add. In general, a confidence interval expresses the statistical uncertainty around an estimate under a specified analysis. It can show which values for a group contrast remain reasonably compatible with the observed data and the analysis assumptions. A narrow interval indicates greater precision than a wide interval, but interpretation also depends on the clinical question and the scale. The registry record does not report a confidence interval for the primary endpoint. A confidence interval cannot be reconstructed from the endpoint definition alone.

Randomization and masking. In general, random allocation aims to make study groups comparable in expectation with respect to factors present at baseline. Masking can reduce the influence of expectations on participant behavior, assessment, or study conduct. The registry labels allocation randomized and masking double, but does not describe the specific procedures. The labels should therefore be treated as the reported design characteristics, not as enough detail to judge how well allocation concealment or masking was implemented. The parallel model indicates that the record describes separate groups rather than a crossover design.

Repeated visits and eye-level measurements. The endpoint was collected for each eye individually at multiple visits. In general, measurements from the same person, including measurements from two eyes or repeated visits, may be correlated rather than independent. Statistical methods sometimes account for such clustering or repeated measures. The registry does not report whether or how any such dependence was handled. It also does not report whether the primary analysis treated eyes, people, or another unit as the independent observational unit. These details matter for interpreting standard errors and confidence intervals, but no such inferential quantities are reported.

Hypothesis testing and the registry statement. A formal hypothesis test evaluates data against a specified statistical null hypothesis using a defined test procedure. The primary outcome description states that no formal hypothesis testing was planned. The record consequently provides no reported p-value or test result for this endpoint. A descriptive mean should not be converted into a claim of statistical significance or lack of significance. No post hoc test or alternative model should be attributed to the study without documentation in the registry record.

Planning calculations are not observed power. In general, sample-size planning depends on a target effect, variability assumptions, allocation, and an error-rate convention. Any planning illustration based on an observed effect is a hypothetical calculation for future planning; it is not the study's observed power and does not show whether the study was adequately powered for its original aim. The record gives assumptions for a planning illustration, including a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, but it does not report the planning outputs or a sample-size justification for the trial's own design. The illustration must not be interpreted as the design rationale or as evidence about the probability that the study found a real effect.

Counts and over-dispersion in general. For count outcomes, over-dispersion means that observed variability exceeds what a simple count model expects; it can affect standard errors and interval estimates. That general issue does not supply an analysis method for this continuous VA endpoint. The registry does not report a count-outcome model for the primary endpoint. The adverse-event entries are counts, but the record does not report inferential comparisons or model-based uncertainty for them.

Taken together, the registry record permits a reader to identify the endpoint scale, direction, summary type, measurement schedule, and stated absence of formal testing. It does not permit reconstruction of an analysis model, adjusted treatment effect, confidence interval, or formal test. The statistical interpretation should remain descriptive unless additional analysis details and numerical results are reported.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is defined at several scheduled assessments: dispense, Week 1, Week 2, Month 1, Month 2, and Month 3. When a study examines outcomes at multiple time points, multiple comparisons can raise a general multiplicity concern: the more comparisons considered, the greater the chance of finding an apparently notable result by chance if each is treated as a separate test. The registry says that no formal hypothesis testing was planned and its skip note says the primary outcome has several categories or time points and was not reduced to one comparison. A multiplicity adjustment or prespecified strategy for selecting or combining time points is not reported in the registry record.

The analysis population is described as enrolled and dispensed subjects or eyes that completed the study and had data at the corresponding in-person visit. This definition is important because it does not describe an analysis of all enrolled participants regardless of follow-up. The numbers contributing data at each visit and the amount or pattern of missing data are not reported. Reasons for missed visits, withdrawals, or incomplete measurements are also not reported in the registry record.

In general, missing outcome data can affect interpretation if the likelihood of missingness is related to the outcome or differs across groups. Common approaches include analyses based on observed measurements, imputation, or sensitivity analyses under different assumptions. The record does not say which, if any, approach was used, nor does it report a missing-data sensitivity analysis. It is therefore not possible to judge whether missingness may have altered the descriptive results.

The registry does not report a full statistical analysis plan, a prespecified primary visit for a formal comparison, or procedures for handling repeated measurements and multiple eyes per participant. Those omissions limit assessment of analysis choices, but they do not establish that any particular method was or was not used outside the registry record.

11. 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 safety record lists groups for pre-treatment, LID018869 ocular, LID018869 nonocular/systemic, Biofinity ocular, and Biofinity nonocular/systemic. For each listed group, the serious-event count is 0 and the other-event count is 0; the death count is also 0. The risk counts are recorded separately for serious and other events. These entries describe the posted counts for the named groups and should not be combined into an overall rate without knowing the appropriate unit, exposure period, and analysis method.

A zero count means that no event was recorded in that category for the listed group in the registry entry. It does not demonstrate that the possibility of such an event is absent. Event counts are affected by the number of people or observations at risk and by the duration and completeness of follow-up. The registry record does not report confidence intervals, comparative safety tests, definitions of the event categories, or an explanation of the denominator units. It also does not provide any serious adverse-event terms; the list of top serious terms is empty.

The pre-treatment group is listed separately from the lens-period groups, and the ocular and nonocular/systemic categories are also distinct. These distinctions should be retained when describing the counts. The registry entries alone do not support a conclusion that one lens has lower risk than the other, nor do the counts replace a fuller account of safety monitoring and event ascertainment.

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

The record establishes the study's stated purpose, design labels, lens-wear schedules, primary endpoint definition, and safety counts. It identifies a randomized, double-masked, parallel-group evaluation of Lehfilcon A and Comfilcon A contact lenses during daily wear with monthly replacement. It also identifies distance VA in logMAR with study lenses in place as the primary outcome and specifies that measurements were summarized as means and standard deviations across scheduled visits.

The record does not report the numerical VA results, a treatment-group contrast, or uncertainty around a contrast. As a result, it cannot establish how similar or different the observed visual-acuity measurements were between the groups. The registry's statement that formal hypothesis testing was not planned is especially important: the outcome description should not be presented as a formal test of superiority, equivalence, or non-inferiority. No margin for equivalence or non-inferiority is reported in the registry record.

The listed safety data show zero serious events, zero other events, and zero deaths in each named risk group. Those counts are informative as recorded observations, but they do not establish that an event could not occur or quantify comparative safety with precision. The record does not report interval estimates or a statistical safety comparison.

More broadly, registry information is not a substitute for a complete statistical report. The sample-size justification, detailed analysis methods, visit-specific outcome counts, missing-data handling, and numerical efficacy results are not reported in the registry record. Without those details, readers cannot evaluate precision, the influence of incomplete follow-up, or the extent to which the analyses followed a prespecified plan. The appropriate conclusion is limited: the registry describes the study's design and measurement plan and records the listed event counts, while leaving comparative outcome results and their statistical uncertainty unreported.

13. Why This Trial Matters Statistically

This trial is statistically notable for the difference between having a clearly described endpoint and having a reported inferential result. Distance VA is defined in a recognizable clinical scale, the direction of that scale is explained, and the schedule indicates when measurements were intended to occur. These details help readers understand what the endpoint represents. But because numerical outcome summaries and a formal group comparison are not reported in the registry entries, readers cannot quantify the observed difference or its precision.

The endpoint is assessed separately for each eye and at repeated visits. In general, both features can require careful choices about the observational unit and dependence among measurements. Treating correlated measurements as independent can misstate uncertainty. The record does not report the handling of these features, so it is not possible to judge the approach or reproduce an analysis.

The stated analysis population also matters. It includes enrolled and dispensed subjects or eyes with study completion and data at the corresponding in-person visit. This does not by itself reveal how many measurements were available at each visit or whether missingness differed between groups. Visit-specific counts and missing-data methods would help readers assess the completeness and stability of the descriptive summaries.

Finally, the registry's explicit statement that formal hypothesis testing was not planned places an important boundary on interpretation. Descriptive endpoint summaries and safety counts can be valuable, but they should not be turned into unsupported claims of statistical significance or comparative effectiveness. A complete account of numerical results, uncertainty, and analysis decisions would be needed to support those judgments.

14. 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 main limitation for statistical interpretation is that numerical primary endpoint results are not reported in the registry entries. There are no group means or standard deviations, no between-group estimate, and no confidence interval or p-value. Since formal hypothesis testing was not planned, the registry does not provide an inferential comparison of the lens groups. The endpoint definition alone cannot establish the direction or size of an observed difference.

The outcome covers several visits, but the registry record does not report visit-specific numbers of contributing participants or eyes, or identify one visit as the sole formal comparison. The listed analysis population is restricted to enrolled and dispensed subjects or eyes who completed the study and had corresponding in-person visit data. The number and characteristics of observations excluded by this definition cannot be assessed from the record.

Details needed to evaluate the statistical analysis are also absent. The record does not report the model, handling of repeated visits or paired eyes, missing-data approach, adjustment for multiplicity, or any sensitivity analyses. It does not report the trial's sample-size justification or a complete statistical analysis plan. Although planning assumptions are stated for an illustration, the planning outputs are not reported and the illustration is not the trial's own design rationale.

Design reporting is limited as well. The registry labels the study randomized and double-masked but does not explain the randomization process, allocation concealment, or which groups of people were masked. CLEAR CARE is listed as an intervention, but its role is not reported. The safety record gives counts without uncertainty estimates or a full description of event ascertainment and denominator units. These limitations restrict what can be concluded from the registry record; they do not establish that additional information is unavailable elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Clinical Evaluation of a Daily Wear Monthly Replacement Silicone Hydrogel Lens — NCT04178720.
• Registry record last updated 2021-10-19; status last verified 2021-09.
• Results first posted 2021-05-13.
• 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.

18. Record Summary

NCT04178720 is a completed randomized, double-masked, parallel-group clinical study sponsored by Alcon Research, with enrollment of 119 and recorded phase NA. It evaluated Lehfilcon A against Comfilcon A contact lenses for daily wear and monthly replacement. The arm descriptions specify bilateral use, nightly removal for cleaning and disinfection, and a 3-month wear period.

The primary endpoint was distance VA in logMAR with study lenses in place, measured at dispense and follow-up visits through Month 3. The registry specifies means and standard deviations and says formal hypothesis testing was not planned. Numerical endpoint results and a group comparison are not reported in the registry entries. Safety entries list zero serious events, zero other events, and zero deaths for each displayed group. The registry record does not report the detailed statistical methods, sample-size justification, visit-specific analysis counts, or missing-data procedures needed for a fuller assessment.