Clinical Evaluation of the Safety and Efficacy of a New Multifocal Contact Lens: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Evaluation of the Safety and Efficacy of a New Multifocal Contact Lens (NCT01797783), a randomized na study. The primary outcome is Subjective Overall Vision.

2. Clinical Question

The clinical question is therefore about how participants rated overall vision while wearing the two study lenses, not about an objective measure of visual acuity alone. Binocular Snellen visual acuity at distance and at near were listed as secondary outcomes. Numerical results for those outcomes are not reported in the registry record.

3. Trial Design

The record describes a randomized, single-masked, parallel-group study of two multifocal contact lenses. It lists Alcon Research as the sponsor and records the study as completed. The study began in 2013-02, with primary completion in 2013-04. The phase is recorded as NA. These registry entries describe the design and status; they do not establish what numerical results were obtained.

One arm received DAILIES® AquaComfort Plus® Multifocal, described as a nelfilcon A multifocal lens with comfort additive. The other received Focus® DAILIES® Progressives, described as a nelfilcon A multifocal lens. Both were worn for 30 days on a daily-wear, daily-disposable basis. The record does not identify who was masked, how masking was maintained, or whether participants could distinguish the lenses.

Enrollment is reported as 83. The allocation ratio and the number randomized to each arm are not reported in the registry record. The adverse-event entries give arm-specific numbers at risk, but those entries should not be treated as a full account of the randomized population or as the primary-outcome sample sizes.

The stated purpose was to demonstrate substantial equivalence between the new lens and the commercially available comparator. The registry record does not report the prespecified equivalence margin, the statistical test planned for that purpose, or the decision rule. It also does not report the protocol's sample-size justification or a detailed statistical analysis plan. Without those details and the outcome estimates, the design description alone cannot establish whether the study met its stated objective.

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 83 consented participants, 2 were exited as screen failures prior to randomization, and 2 were exited after randomization but prior to product dispense. This reporting group includes all randomized participants who were dispensed study product (79).

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: This analysis population includes all randomized and dispensed participants who completed the study. No imputation was used for missing values. Here, "n" is the number of participants with non-missing values at the specific time point for each arm. group,

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 randomized participants who were dispensed study product (79).

6. Primary Endpoint

The registry lists the primary outcome as Subjective Overall Vision, measured over Up to Day 30.

The primary endpoint, Subjective Overall Vision, was a participant rating of the aggregate quality of distance, intermediate, and near vision with the study lenses. Participants were instructed to rate both eyes together and select one response on a continuous scale from 1-10, where 1 meant poor and 10 meant excellent. Higher numbers indicate better rated vision on this scale.

This type of rating captures the participant's combined impression across visual distances. It is distinct from the listed secondary outcomes, which assess binocular Snellen visual acuity at distance and at near (40cm). A subjective rating and an acuity measure describe different aspects of vision; one should not be substituted for the other.

The endpoint is reported as a mean with standard deviation, with a timeframe of up to Day 30. The mean describes the average rating, while the standard deviation describes how dispersed participant ratings are around that average. Neither quantity, nor a between-lens contrast, is reported in the registry record. The record's outcome description explains the scale and population but does not provide numerical primary-endpoint results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: it records a rating on a numerical scale rather than classifying participants into a small set of outcome categories. The record describes the primary measure using a mean and standard deviation. These summaries answer different questions. The mean represents the center of the observed ratings, while the standard deviation describes their spread. A standard deviation is not a confidence interval and does not directly quantify uncertainty in the mean or in a between-arm comparison.

What would a between-arm estimate mean?

In a randomized parallel-group study, a between-arm estimate would compare the outcome summaries for participants assigned to the two lenses. Such an estimate would describe the observed contrast in ratings for the analyzed participants. Its interpretation depends on the direction of subtraction and the scale: higher ratings indicate better vision, but the registry record does not report a contrast or specify a contrast direction. No numerical estimate should be inferred from the intervention descriptions or enrollment entry.

General explanation: estimates are more informative when accompanied by an uncertainty interval. A confidence interval represents a range of values compatible with the observed data and the statistical method, under its assumptions. It helps distinguish a precisely estimated small contrast from an imprecisely estimated contrast that could include a broader range of values. The interval does not guarantee that the true value lies within it, and it does not by itself determine whether a difference is clinically meaningful. No confidence interval is reported for the primary outcome in the registry record.

How does equivalence differ from a conventional difference test?

General explanation: a conventional test for a difference often evaluates whether the data are inconsistent with a null hypothesis of no difference. An equivalence assessment asks a different question: whether the uncertainty around the estimated contrast is sufficiently contained within prespecified bounds on both sides. Those bounds are called an equivalence margin. A nonsignificant difference test alone is not evidence of equivalence, because an imprecise estimate may be compatible with both small and substantial differences.

The registry record states that the study's purpose was to demonstrate substantial equivalence. It does not report the equivalence margin, the formal statistical procedure, the confidence level used for an equivalence assessment, or a result. Therefore, the stated objective cannot be evaluated from the posted numerical information in the registry record. These missing details should not be replaced by assumptions about a standard approach.

What can a p value tell a reader?

General explanation: a p value describes how unusual data at least as incompatible with a specified null hypothesis would be if that hypothesis and the model assumptions were true. It does not measure the probability that a treatment effect is real, the size of an effect, or the probability that the result will replicate. A p value also cannot establish equivalence without the appropriate margin-based analysis. A p value for the primary comparison is not reported in the registry record, and the record lists 0 analyses.

Why do variation and distribution matter?

General explanation: the spread of individual ratings affects how precisely a group mean and a between-group contrast can be estimated. The mean and standard deviation can be useful summaries, but they do not show the full distribution. Ratings may cluster, spread unevenly, or be influenced by unusually high or low observations. Looking at distributions can reveal features that a single average conceals. The registry record does not provide the primary outcome's mean, standard deviation, or participant-level distribution, so those features cannot be assessed.

Over-dispersion is a general concern when observed variability exceeds what a model assumes. If a model understates variability, standard errors may be too small and inferential results may appear more precise than warranted. This concept is relevant when choosing a model for data, but no evidence of over-dispersion or model choice is reported for this trial. The primary outcome is described as continuous, so count-data models and count-specific over-dispersion adjustments should not be presumed to apply.

What do the planning assumptions represent?

The planning illustration is described as a calculation based on the observed effect, not the trial's original design. It assumes a two-sided significance level of 0.05, equal allocation, and a normal approximation; its target effect is a stated fraction of the observed effect. Such calculations are prospective planning illustrations: they ask what sample size might be needed under chosen assumptions. They are not observed power and do not show the probability that this completed trial detected an effect. No numerical planning estimates are reported in the registry record.

General explanation: sample-size planning depends on the target effect, variability, allocation, significance criterion, and desired power. Changing an assumed target effect changes the planning result. A calculation based on an observed effect can be especially dependent on that estimate, which may be uncertain. It should not be mistaken for the trial's original design rationale. The record does not report the protocol's sample-size justification or an observed-power analysis.

These statistical concepts clarify how continuous outcomes, uncertainty, equivalence, and planning calculations are ordinarily interpreted. They do not supply missing trial results. For this study, the actual primary-outcome estimates, their uncertainty, and the analysis supporting the stated equivalence objective are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The primary analysis population is described as all randomized and dispensed participants who completed the study. No imputation was used for missing values. The record defines “n” as the number of participants with non-missing values at the specific time point for each arm. This means the outcome-specific denominator may depend on which participants had a recorded rating at that time point; the primary-outcome denominators are not reported in the registry record.

The registry record does not report reasons for missing outcome values, whether missingness differed between arms, or sensitivity analyses addressing missing data. Without those details, readers cannot assess whether the observed ratings might represent a selected subset of participants or how robust an analysis would be to alternative assumptions about missing values. No imputation means missing values were not filled in under an imputation procedure, but it does not by itself show that missing data had no effect on the result.

Three outcome measures are listed: Subjective Overall Vision, binocular Snellen visual acuity at distance, and binocular Snellen visual acuity at near (40cm). The record does not report a multiplicity adjustment, a hierarchy for interpreting the outcomes, or a detailed analysis plan. When several outcomes or comparisons are considered, multiplicity can increase the chance of at least one apparently notable result by chance. General methods for addressing this include prespecifying a primary outcome, adjusting inference, or using a defined testing hierarchy; which approach was used is not reported in the registry record.

The record lists 0 analyses, and its available outcome structure was not reduced to one primary comparison. Consequently, there are no reported inferential results on which to assess multiplicity or missing-data sensitivity. The completion-only population description also means that randomized participants who did not complete the study are not described as part of this primary analysis population.

11. 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 adverse-event entries report serious adverse events for the two arms separately. For DAILIES® AquaComfort Plus® Multifocal, 52 participants were at risk and 0 were reported as affected by a serious adverse event. For Focus® DAILIES® Progressives, 27 participants were at risk and 0 were reported as affected by a serious adverse event. The registry record does not list serious adverse-event terms.

The entries also report other adverse events: 52 were at risk and 0 affected in the DAILIES® AquaComfort Plus® Multifocal arm; 27 were at risk and 0 affected in the Focus® DAILIES® Progressives arm. These are the registry's arm-specific safety counts, not a substitute for the primary vision outcome or a complete account of every possible safety detail.

Death counts are not reported in the registry record. The record does not provide event descriptions, severity grading, relatedness assessments, or timing for the safety entries. A report of 0 affected in these categories should be read narrowly as the posted count for the listed event category and arm. It does not establish that no unlisted event occurred or resolve the missing details about safety monitoring.

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

The record identifies a randomized comparison of two multifocal contact lenses and defines a participant-rated primary outcome. It also states that the study sought to demonstrate substantial equivalence. These registry entries explain the intended comparison, but they do not establish what participants reported or whether the lenses met the study's objective.

The primary scale ranges from 1-10, with higher numbers meaning better vision. However, the record does not report the mean rating in either arm, the standard deviation, or the estimated difference. It also does not report a confidence interval, p value, equivalence margin, or the result of an equivalence analysis. Without these items, the direction, size, and precision of the comparative outcome cannot be described.

The absence of a reported numerical comparison is not evidence that the lenses had the same ratings, and it is not evidence that they differed. Likewise, a completed status does not indicate that an equivalence criterion was met. The study's stated aim should be kept distinct from a demonstrated result.

General explanation: a finding of equivalence requires evidence that the plausible values for the between-group contrast lie within prespecified limits. Those limits represent the largest differences considered compatible with the intended equivalence claim. The limits and the relevant analysis are not reported in the registry record. A conventional test that does not identify a statistically significant difference would not, on its own, establish equivalence.

Safety entries report 0 serious adverse events and 0 other adverse events affected in each arm, with the arm-specific numbers at risk recorded separately. Those entries are limited to the categories and information recorded. Death counts are not reported in the registry record. They do not answer the comparative vision question, and they should not be used to infer unreported safety details.

In sum, the registry record supports a description of the study question, lenses, outcome definition, and posted safety counts. It does not support a conclusion about comparative vision ratings, the precision of a treatment contrast, or whether substantial equivalence was demonstrated. Those conclusions would require results and analysis details that are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically notable for the distinction between a stated equivalence objective and the evidence needed to evaluate that objective. The registry record says the study sought to demonstrate substantial equivalence, but it does not report the equivalence margin or numerical primary-outcome results. This makes clear why the objective alone cannot be read as a conclusion.

The primary measure is a subjective rating that combines distance, intermediate, and near vision. Its scale direction is explicit, and its mean and standard deviation are the stated summary measures. Those details allow readers to understand what the outcome represents, while also highlighting what remains unavailable: the observed values and the uncertainty around a between-arm comparison. A defined outcome is not the same as a reported result.

The record also describes an analysis population restricted to randomized and dispensed participants who completed the study, with no imputation for missing values. This makes denominator transparency and missing-data reporting important for interpreting any future numerical estimate. The record defines outcome-specific non-missing participant counts, but does not report those counts for the primary endpoint or explain missingness.

Finally, the record lists secondary visual-acuity outcomes and 0 analyses. With multiple outcomes, prespecified priorities and multiplicity handling can affect how inferential claims should be read. The registry record does not describe those methods. General statistical practice emphasizes that outcome definitions, estimands, uncertainty, missing data, and decision criteria all contribute to interpretation; none can be replaced by a study's completion status or stated purpose.

The trial therefore illustrates a broader reporting lesson: statistical interpretation depends not only on the design and measurement plan but also on the estimates, uncertainty, and decision rules. Without those results, readers can identify the question the study addressed, but cannot assess the strength or precision of the evidence for its intended equivalence claim.

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 principal limitation for interpreting this trial from the registry record is the absence of numerical results for the primary outcome. Arm-specific means, standard deviations, a contrast, and an uncertainty interval are not reported. The record therefore does not permit assessment of the observed difference or its precision.

The equivalence objective is stated, but the margin and analysis used to assess equivalence are not reported in the registry record. Without a defined margin and relevant results, the stated objective cannot be evaluated. The record also does not report the protocol's sample-size justification, detailed statistical plan, or any interim-analysis information.

The primary-outcome population is defined as randomized and dispensed participants who completed the study, and no imputation was used. The record does not report primary-outcome denominators, reasons for missingness, or sensitivity analyses. This limits assessment of how missing data may have affected the analyzed ratings. Allocation ratio and arm-specific randomized counts are also not reported in the registry record.

Although single masking is recorded, the masked party and practical masking procedures are not reported. The record does not describe baseline characteristics, adherence, lens discontinuation, or how deviations from the intended wearing schedule were handled. These details are not available for judging comparability or the conduct of the study.

The record lists secondary visual-acuity outcomes, but their numerical results are not reported. It also lists 0 analyses and does not report how multiple outcomes were handled statistically. Safety entries provide counts for serious and other adverse events, but do not report death counts or further event-level details. These limits describe what the registry record does not report; they do not establish that the corresponding procedures or events were absent.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Clinical Evaluation of the Safety and Efficacy of a New Multifocal Contact Lens — NCT01797783.
• Registry record last updated 2014-05-23; status last verified 2014-04.
• Results first posted 2014-05-23.
• 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 NCT01797783 as a completed, randomized, single-masked, parallel study sponsored by Alcon Research. Enrollment was 83. Its stated purpose was to demonstrate substantial equivalence of DAILIES® AquaComfort Plus® Multifocal to Focus® DAILIES® Progressives. Both lenses were described as daily-wear, daily-disposable lenses worn for 30 days.

The primary outcome was Subjective Overall Vision, rated on a continuous 1-10 scale, with higher ratings indicating better vision. The primary analysis population comprised randomized and dispensed participants who completed the study; no imputation was used for missing values. Binocular Snellen visual acuity at distance and near (40cm) were listed as secondary outcomes.

Numerical primary and secondary outcome results, an equivalence margin, and the analysis supporting the equivalence objective are not reported in the registry record. Safety entries report 0 serious and 0 other adverse events affected in each arm. Death counts are not reported.