Clinical Study of Approved Contact Lenses: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Study of Approved Contact Lenses (NCT03351101), a randomized na study. The primary outcome is End of Day Comfort.

2. Clinical Question

The study compared Senofilcon C and Samfilcon A soft contact lenses. Its primary question concerned participants’ end-of-day comfort after wearing the lenses, assessed at 1 month. The registry describes the study as an evaluation of Johnson and Johnson Acuvue Vita (senofilcon C) and Bausch and Lomb Ultra (samfilcon A).

The question is about a participant-reported experience rather than a clinical event or a measure of visual function. The questionnaire asked participants to evaluate lens performance, with higher scores indicating greater comfort. That makes the endpoint a direct measure of the experience the study set out to assess, though it does not by itself describe other aspects of lens performance.

The registry reports a median score of 80 in each arm. These matching medians are descriptive summaries. They do not establish that the lenses have equivalent comfort, nor do they show how likely a difference might be in a broader population. The registry record does not include an estimable comparison, confidence interval, or hypothesis-test result for the primary endpoint.

3. Trial Design

This was a randomized, parallel-group study with triple masking. The registry lists the phase as NA and the status as completed. Its official title is Clinical Study of Approved Contact Lenses, and it lists myopia as the condition. Bausch and Lomb Incorporated is identified as the sponsor.

The registry records enrollment of 271 participants. The study started on 2017-10-23 and lists 2017-11-10 as the primary completion date. These are registry dates; they do not provide details about how long each participant used a lens or the timing of individual study visits. The primary endpoint timeframe is reported as 1 month.

Random allocation means that assignment to the study arms was intended to be determined by chance rather than participant or investigator choice. In general, randomization helps limit systematic differences between groups at the time of assignment. The registry does not report the sequence-generation procedure, allocation concealment, or other operational details, so those features cannot be assessed from this record.

Parallel-group means participants were assigned to an arm rather than described as switching between the two lenses. Triple masking indicates that masking was recorded, but the registry does not identify which groups of people were masked or explain how masking was maintained. Those details are not reported in the registry record.

The endpoint summaries are based on 115 participants in the Senofilcon C arm and 106 in the Samfilcon A arm. The registry defines the primary endpoint population as participants who completed all study visits without a major protocol deviation. These arm counts are therefore not a description of everyone enrolled, and the record does not explain the relationship between enrollment, assignment, and inclusion in the endpoint summaries.

The record lists two outcome measures and zero posted analyses. It does not report a protocol-level statistical analysis plan, a planned sample-size justification, or an explanation of the masking procedures. The trial design can therefore be described from the recorded allocation, masking, and parallel model, but not fully reconstructed.

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

Analysis population for the primary outcome, as defined in the registry: All participants that completed all study visits without a major protocol deviation.

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: All participants that completed all study visits without a major protocol deviation.

6. Primary Endpoint

The registry lists the primary outcome as End of Day Comfort, measured over 1 month.

The primary endpoint was End of Day Comfort, assessed at 1 month. It was measured using a take-home questionnaire in which participants evaluated lens performance based on their responses. The registry describes a score on a 100-point scale, with possible scores from 0 to 100. Higher values indicated greater comfort.

A participant-reported comfort measure is useful when the research question concerns how wearing a lens feels to the participant. It captures an experience that may not be represented by a clinical examination alone. A scale also gives a structured way to record responses across participants, although the interpretation depends on how the questions are worded and how responses are combined. Those questionnaire details are not reported in the registry record.

The endpoint population is described as all participants who completed all study visits without a major protocol deviation. This definition matters because a summary from that group need not represent every person randomized. The registry does not report how many participants were excluded from the endpoint population, why any were excluded, or how missing questionnaires were handled.

The record labels the endpoint statistic as a median and the dispersion as a standard deviation. The posted median is 80 in each arm; the reported standard deviations are 18.15 for Senofilcon C and 20.46 for Samfilcon A. A median describes the central position of ordered scores, while a standard deviation describes spread around a mean. Pairing a median with a standard deviation is less conventional than pairing a median with a measure based on ordered values, so the distribution and the summary choices cannot be fully evaluated from the record alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies this as a randomized, triple-masked, parallel-group study, but it does not report a detailed statistical analysis plan. The following statistical concepts are general explanations; they should not be mistaken for methods confirmed to have been used in this trial.

What does the median describe?

In general, the median is the middle value after observations are ordered. It is often useful for scores because it is less affected by unusually high or low observations than the mean. A median does not show the full pattern of responses: different distributions can share the same median. Here, the posted medians are 80 in both arms, but the registry does not give participant-level scores, a histogram, or other distributional detail.

How should the standard deviations be read?

In general, a standard deviation describes the spread of observations around their mean. A larger standard deviation indicates more dispersion around that mean, but it does not show the shape of the distribution or the precision of a comparison between groups. The registry reports a median together with a standard deviation for each arm. That combination is not the most usual pairing of a central summary with a spread measure, and the record does not explain its rationale. The reported values cannot substitute for a confidence interval for the difference between arms.

Why is an uncertainty interval useful?

In general, a confidence interval gives a range of values compatible with an estimate under the assumptions of the analysis. It communicates precision as well as direction and magnitude. A narrow interval suggests more precision than a wide interval, while an interval that includes values on different sides of a null comparison may leave the direction uncertain. This record does not report a confidence interval for the primary comparison, and the comparison is identified as not estimable. No interval should be inferred from the arm summaries alone.

What would a group comparison require?

In general, comparing two randomized groups requires a defined estimand and an analysis appropriate to the outcome and study design. An estimand specifies the treatment contrast of interest and how outcomes after events such as discontinuation or protocol deviations are handled. A statistical model or test then uses observed data and assumptions to estimate that contrast and its uncertainty. The registry record does not report the intended estimand, test, model, or assumptions for the primary endpoint. Randomization describes assignment, but does not by itself supply these analysis details.

A comparison may be unestimable when information required for the intended analysis is unavailable or a result cannot be calculated under the analysis used. The reason is not reported in the registry record. It would be inappropriate to infer the cause from the matching medians, the arm counts, or the endpoint description. The registry’s note that values were missing or not estimable for a two-arm comparison is the available explanation.

How does the planning illustration differ from trial design?

In general, a sample-size calculation asks how many participants would be needed under stated assumptions to detect a specified effect with a chosen statistical procedure. The registry describes planning illustrations based on an observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. Such illustrations are planning exercises, not evidence about the trial’s design rationale or its chance of detecting an effect after the study is complete. The record explicitly distinguishes those illustrations from the trial’s own design. It does not report the trial’s sample-size justification.

Planning calculations also depend on the outcome definition, variability, target effect, and analysis assumptions. If those assumptions differ from the actual trial conditions, the resulting planning figures may not describe the performance of the completed study. A planning calculation is not observed power. The registry does not provide a protocol rationale that would establish how the planned enrollment was chosen.

Why does variability matter?

In general, variability affects how precisely a study can estimate a group contrast. Greater variation in individual scores can make a group-level estimate less precise if other design features remain the same. The standard deviations reported for this endpoint describe within-arm spread, not the uncertainty of a treatment contrast. The registry does not report an inferential model that would translate the posted summaries into a valid interval or test.

Over-dispersion is a general concern when data vary more than a statistical model assumes. If a model understates variability, it can produce uncertainty estimates that are too small. This concept is relevant when choosing and checking a model, but the record does not report a model or evidence of over-dispersion for this questionnaire outcome. It cannot be concluded that over-dispersion occurred or that it affected the results.

Because the endpoint uses a bounded score, its possible values are limited to 0–100. In general, bounded outcomes may have distributional features that differ from an unbounded normal outcome, particularly near scale limits. Whether that matters for a particular analysis depends on the observed distribution and chosen method. The registry does not report enough information to assess those features or identify the method used.

Overall, the record supports a descriptive reading of the posted arm summaries and study design. It does not support reconstruction of the primary statistical analysis, calculation of a comparison, or a judgment about the precision of a treatment contrast.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and zero secondary outcomes posted. It reports zero posted analyses. The record does not describe a prespecified hierarchy of outcomes, an adjustment for multiple comparisons, or how the two outcome measures relate to the analysis plan. Those details are not reported in the registry record.

Multiplicity is a general issue that arises when several outcomes, time points, or analyses are tested. Conducting many tests can increase the chance of observing a seemingly notable result by chance. In general, an analysis plan may address this by identifying a primary outcome or adjusting the interpretation of multiple tests. The record labels End of Day Comfort as the primary endpoint, but does not provide enough information to determine how multiplicity was handled across all planned outcomes or analyses.

The primary endpoint population is defined as participants who completed all study visits without a major protocol deviation. That is a stated analysis population, but the record does not report whether other populations were analyzed, such as all randomized participants. It also does not report how many participants had missing endpoint data, the reasons for missingness, or whether any imputation or sensitivity analysis was used. Missing-data handling is therefore not reported in the registry record.

These omissions limit assessment of how representative the endpoint summaries are of the randomized groups. In general, analyses restricted to participants with complete visits can be affected if completion is related to outcomes or group assignment. That possibility is a general methodological concern, not a finding about this trial; the registry does not provide the information needed to determine whether it occurred.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for 136 participants at risk in the Senofilcon C group and 132 participants at risk in the Samfilcon A group. It records zero serious adverse events in each group and zero deaths in each group. These are the posted registry counts and denominators.

For other adverse events, the record reports zero among 136 at risk in the Senofilcon C group and one among 132 at risk in the Samfilcon A group. The registry does not provide a serious adverse event term, because no serious adverse event terms are listed. It also does not identify the term or details of the reported other adverse event in the information available in the record.

Adverse-event counts describe events recorded under the registry’s reporting categories. They do not establish that no events of any kind occurred, and they do not alone establish a causal relationship to a lens. In general, safety comparisons depend on definitions, follow-up, ascertainment, and the completeness of reporting. Further details about these matters are not reported in the registry record.

The safety counts should be interpreted separately from the comfort endpoint. The at-risk counts are not the same as the endpoint summary counts, and the registry does not explain the difference. The absence of reported serious events in these groups is a description of the posted record, not a conclusion about safety beyond the study data.

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

The registry records a randomized comparison of two soft contact lenses and reports end-of-day comfort scores at 1 month. Both arms have a median score of 80, with standard deviations of 18.15 for Senofilcon C and 20.46 for Samfilcon A. Those values summarize the participants included in the endpoint summaries and use a scale where higher scores indicate greater comfort.

The record does not report an estimable comparison between the arms. There is no posted confidence interval or p-value for the primary endpoint. As a result, the registry does not establish whether any difference exists, how large a difference might be, or how precisely a between-arm effect has been estimated. Matching medians are not a test of equivalence and do not show that the score distributions are the same.

The result also does not answer whether one lens is preferable for every participant or whether comfort would be similar in populations beyond the study. The registry record does not report a threshold for a meaningful score difference, detailed eligibility criteria, or the full distribution of questionnaire responses. The summaries should not be extended beyond the endpoint and population actually described.

Similarly, the safety counts are limited to the events recorded in the registry. Zero reported serious adverse events in each arm does not establish the absence of all harms. The record provides no event terms for the single other adverse event reported in the Samfilcon A group, and does not explain the event’s circumstances or attribution.

The most defensible reading is therefore descriptive: the registry reports the same median comfort score in each arm, alongside arm-specific spread summaries, but does not provide an inferential comparison. It records no serious adverse events or deaths in either group and one other adverse event in the Samfilcon A group. These statements characterize the posted results without establishing comparative efficacy, equivalence, or broader safety.

13. Why This Trial Matters Statistically

This trial illustrates why a randomized design and a reported result are not the same as a complete statistical answer. Random allocation and parallel groups describe how the comparison was organized. The primary endpoint summaries show the observed comfort scores in the stated endpoint population. But a reader also needs a defined comparison and an estimate of its uncertainty to judge what the data say about differences between groups.

Here, the two posted medians are both 80, yet the registry does not provide an estimable two-arm comparison. That distinction is important: descriptive summaries can be informative, but they do not establish that groups are equivalent or that a difference is absent. Without a comparison estimate and an uncertainty measure, the precision of any contrast remains unknown.

The endpoint also highlights the need to interpret summary statistics in context. A median is a central summary, whereas a standard deviation describes spread around a mean. The registry’s pairing of these statistics, without a distribution or explanation, leaves questions about the shape and variability of responses. Transparent reporting of the analysis method and outcome distribution would help readers assess whether the summaries are well matched to the data.

Finally, the endpoint population is defined by visit completion and absence of major protocol deviations. Clear reporting of exclusions, missing data, and analysis populations is important because the observed participants may not represent everyone randomized. These are broadly relevant issues in clinical research, and the missing details in this record make them particularly visible.

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 is that the registry does not report an estimable two-arm comparison for the primary endpoint. The posted medians are descriptive, and no confidence interval or test result is available to characterize uncertainty about a contrast. The reason the comparison was not estimable is not reported in the registry record.

The record labels the primary statistic as a median and its dispersion as a standard deviation, but gives no explanation for that choice. It does not report the underlying score distribution, questionnaire items, scoring procedure beyond the stated scale, or evidence about the scale’s measurement properties. Those omissions limit interpretation of the endpoint summaries.

The stated endpoint population excludes participants who did not complete all study visits or had a major protocol deviation. The registry does not give the number excluded, reasons for exclusion, missing-data methods, or results from any alternative analysis population. It is therefore not possible to assess how exclusions may have affected the summaries.

Although the study is described as randomized and triple-masked, details about the randomization procedure, concealment, and which parties were masked are not reported in the registry record. The statistical analysis plan, sample-size justification, and multiplicity approach are also not reported. The registry’s planning assumptions are explicitly described as illustrations rather than the trial’s own design rationale.

For safety, the record reports event counts but does not supply terms or further descriptions for the other adverse event. It also does not provide details about event ascertainment or attribution. These limitations concern the available registry reporting and should not be taken as evidence that unreported methods or events did or did not occur.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Clinical Study of Approved Contact Lenses — NCT03351101.
• Registry record last updated 2021-01-08; status last verified 2021-01.
• Results first posted 2020-09-16.
• 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

The registry record describes a completed, randomized, triple-masked, parallel-group study of Senofilcon C and Samfilcon A soft contact lenses in participants with myopia. Enrollment was 271. The study started on 2017-10-23, and primary completion is listed as 2017-11-10. The sponsor is Bausch and Lomb Incorporated.

The primary endpoint was end-of-day comfort at 1 month, measured by a take-home questionnaire scored from 0 to 100, with higher scores indicating greater comfort. The posted median was 80 in each arm. The registry reports standard deviations of 18.15 and 20.46, respectively, and defines the endpoint population as participants who completed all study visits without a major protocol deviation.

The registry does not provide an estimable two-arm comparison or a detailed analysis plan. It reports zero serious adverse events and zero deaths in each group, and one other adverse event in the Samfilcon A group. These are descriptive registry findings; the record does not establish equivalence or a comparative treatment effect.