Dispensing Evaluation of Investigational Contact Lenses: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Dispensing Evaluation of Investigational Contact Lenses (NCT02625220), a na na study. The primary outcome is Proportion of Eyes With Monocular Visual Acuity Better Than 20/40.

2. Clinical Question

3. Trial Design

The registry record describes NCT02625220, titled Dispensing Evaluation of Investigational Contact Lenses. It is marked completed and lists an enrollment of 177. The study is classified as a single-group, non-randomized dispensing evaluation of a prototype toric lens made from senofilcon A. The record lists no phase and does not report an allocation scheme beyond “NA.”

Participants were to wear the prototype lens bilaterally for 6-8 days as a daily disposable modality. The brief summary describes a 2-visit study and names visual acuity, rotational performance, lens fit, stability and subjective characteristics as evaluation areas. The primary endpoint was measured at 7 day follow-up. The record lists a start date of 2015-10, primary completion in 2015-11, and status as completed.

The record contains an inconsistency about masking. Its masking classification is “NONE,” while the brief summary calls the study single-masked. It does not explain the difference, so the masking arrangement cannot be resolved from the registry entry alone. The sponsor is Johnson & Johnson Vision Care, Inc.

Because this is a single-arm study, its design can describe outcomes observed after dispensing the prototype lens but cannot provide a randomized estimate of a difference between lens types or study groups. No control condition is listed. Details such as the specific recruitment and examination procedures beyond the brief summary are 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: A total of 177 subjects were enrolled into this study. Of the enrolled subjects, 7 did not meet the eligibility criteria and 170 subjects were dispensed a study lens. Of the dispensed subjects, 7 were discontinued and 163 completed the study.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The analysis population consists of subjects that completed all study visits without a major protocol deviation (per-protocol). One subject was excluded from the analysis population due to 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 subjects that were dispensed a study lens.

6. Primary Endpoint

The registry lists the primary outcome as Proportion of Eyes With Monocular Visual Acuity Better Than 20/40, measured over 7 day follow-up.

The primary endpoint is the proportion of subject eyes with monocular visual acuity of 20/40 or better at 7 day follow-up. The registry record says that distance Snellen visual acuity was assessed and then dichotomized: an eye counted as a response when acuity was 20/40 or better, and as a non-response when acuity was worse than 20/40. The endpoint is expressed as a proportion of subject eyes.

A threshold-based endpoint turns a measured visual acuity result into a binary classification. Reporting the proportion meeting the threshold can make the endpoint straightforward to interpret as the share of eyes reaching the stated criterion. However, dichotomization discards detail about the actual acuity values and treats eyes on either side of the threshold as different categories, even if their measurements are close.

The registry record does not report the observed count or proportion, an uncertainty interval, or a test result for this endpoint. The measure and its definition are described, but the amount of visual acuity data meeting the criterion cannot be determined from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a proportion endpoint represent? A proportion is the share of the specified analysis units that meet a stated condition. In this study, the unit is a subject eye, and the condition is monocular visual acuity of 20/40 or better at 7 day follow-up. The registry record defines a response as meeting or exceeding that threshold in the stated sense of “20/40 or better”; worse acuity is classified as a non-response. The record does not report the observed numerator or denominator, so it is not possible to state the resulting proportion.

Proportions are commonly used when an outcome is categorical. They can be intuitive because they describe how common a defined result was in the analyzed group. Their interpretation depends on a clear denominator and a clear definition of the analysis units. Here, the record identifies eyes as the endpoint unit, while the analysis-population description is framed in terms of subjects. It does not state how many eyes contributed data or how the two eyes from a participant were handled statistically. That information is important because observations from the same participant may be related rather than independent. The registry record does not report the method used to account for that relationship.

What is lost by dichotomizing visual acuity? Dichotomization assigns observations to categories based on a cutoff. This can simplify communication of a threshold outcome, but it removes information about the underlying measurements. Values categorized together may differ from each other, while values on opposite sides of the cutoff may be close. A binary endpoint also depends on the chosen threshold and on the measurement procedure. The registry record describes the threshold and the use of distance Snellen visual acuity, but does not report distributions of the underlying acuity measurements.

What would an uncertainty interval tell a reader? In general, a confidence interval expresses the uncertainty around an estimated quantity under a specified statistical procedure. For a proportion, it would convey how precisely the observed proportion is estimated in relation to the analyzed sample. A narrow interval would indicate greater precision than a wide interval, subject to the method and assumptions used. The registry record does not report a confidence interval or the endpoint estimate, and it does not identify a statistical procedure for estimating uncertainty. No interval can be inferred from the endpoint definition or enrollment alone.

Why does the single-arm design matter? A single-arm study has no concurrent comparison group in the record. Its observations can describe the participants who received the prototype lens, but they do not yield a randomized between-group treatment effect. Randomization, when used, helps make groups comparable on average; without it and without a comparator, differences from an external benchmark would require additional assumptions and information. No external benchmark is specified in this record. The study's stated purpose is evaluation of visual acuity and lens characteristics, not a documented randomized comparison.

What can the analysis population definition establish? The primary population is described as per-protocol: subjects who completed all study visits without a major protocol deviation. The record says one subject was excluded for such a deviation. This explains a stated eligibility rule for the analysis, but it does not show the final number analyzed, the reasons for any other non-inclusion, or whether all endpoint measurements were available. The exact handling of missing endpoint data is not reported in the registry record.

What does the analysis count mean? The registry record lists four outcome measures and zero analyses. An outcome measure describes what is intended to be measured; an analysis describes a statistical result or procedure applied to data. The distinction matters because listing an endpoint does not communicate an estimate, uncertainty, or hypothesis test. No statistical test, model, covariate adjustment, or interval method is specified in the registry record. It is not possible to characterize the primary analysis beyond the stated endpoint and analysis-population description.

How should planning illustrations be understood? Any sample-size planning illustration based on an observed effect is a hypothetical planning exercise, not a report of what was observed in this study. Such illustrations depend on specified assumptions, including a significance level, allocation, approximation, and effect size to detect. The registry record's planning description refers to a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects expressed as fractions of an observed effect. These are planning assumptions, not evidence that this single-arm trial used a two-arm design or that it had a particular power. The record does not report its own sample-size justification, and no planning value should be read as an observed result or as observed power.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists four outcome measures, but it does not report a multiplicity strategy. Multiplicity arises when several outcomes, time points, groups, or statistical tests are assessed; the chance of at least one apparently unusual result can depend on how many analyses are performed and how they are interpreted. Methods for addressing multiplicity can include prespecifying a primary endpoint and applying an adjustment to a family of tests, but the registry entry does not state whether any such approach was used. It lists zero analyses, so no multiplicity-adjusted or unadjusted result is available in the registry record.

The primary endpoint description identifies a per-protocol population: subjects who completed all study visits without a major protocol deviation. The record states that one subject was excluded because of a major protocol deviation. It does not report how many subjects or eyes were analyzed, whether endpoint data were missing, or how missing measurements were handled. It also does not describe any imputation, exclusion, or sensitivity analysis for missing data.

A per-protocol population can differ from a population defined by enrollment or assignment, because eligibility depends on protocol completion and deviations. The registry record does not give enough information to assess whether the reported analysis population differed in important ways from all enrolled participants. Nor does the entry describe an intention-to-treat analysis or another analysis population. These omissions limit assessment of the potential influence of exclusions and missing measurements on the endpoint.

The registry record does not report a protocol-based analysis plan, a hierarchy for secondary outcomes, or interim analyses. These details should not be inferred from the endpoint list or from the completed status. Without the plan and numerical results, readers cannot assess whether all prespecified outcomes and analyses are reported or whether any analyses were selected after seeing the data.

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 entry lists the prototype toric lens senofilcon A group with 170 participants at risk for serious adverse events and 170 at risk for other adverse events. It records zero serious adverse events and zero other adverse events. No deaths are listed. These figures describe what the registry record reports for that group.

At-risk counts indicate the recorded group size for the relevant adverse-event category, but the entry does not specify exposure time, event definitions, ascertainment procedures, or participant-level details. The study's brief summary describes bilateral lens wear for 6-8 days, but the safety entry does not provide a separate event rate over time. Because no comparison group is listed, these counts do not estimate a relative safety difference between interventions.

Zero reported events is not equivalent to proof that an event cannot occur. It means that the registry entry records no events in the stated categories for the listed group. The entry does not provide further detail about non-serious events, specific symptoms, or how adverse events were collected. Broader conclusions about safety cannot be drawn from these figures alone.

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

The registry record establishes the study's design, intended endpoint, analysis-population rule and recorded adverse-event counts. It describes a completed single-arm dispensing evaluation in which participants wore a prototype senofilcon A toric lens bilaterally for 6-8 days. Its primary endpoint was the proportion of eyes with monocular visual acuity of 20/40 or better at 7 day follow-up.

The record does not report the numerical primary endpoint result. It therefore does not show the proportion of eyes meeting the visual acuity criterion, how uncertain that estimate would be, or how the observed result relates to any prespecified benchmark. Naming an endpoint is not the same as reporting its value. Enrollment of 177 does not fill that gap because the number analyzed and the number of endpoint-contributing eyes are not stated.

The single-arm, non-randomized design also limits the kind of conclusion the study can support. The recorded data are not a randomized comparison between the prototype and another lens. There is no comparator group in the record from which to estimate a difference in outcomes. A result from this design, if reported, would describe observations in the study group and would not alone establish what would have happened under an alternative condition.

The adverse-event entries report zero serious and zero other adverse events among 170 participants at risk in each category. These counts are useful as a description of the recorded experience, but the registry entry does not give event definitions, follow-up details for safety, or a comparison group. They should not be interpreted as a guarantee that adverse events are impossible.

Overall, the registry record gives enough information to identify the question and broad design, but not to evaluate the primary outcome's magnitude or precision. Its interpretation should remain limited to what is actually recorded: a completed single-arm study, a defined visual acuity endpoint, and the stated adverse-event counts.

13. Why This Trial Matters Statistically

This study illustrates why an endpoint definition and an endpoint result are distinct pieces of statistical information. The registry record carefully describes the primary measure as a proportion of subject eyes meeting a Snellen visual acuity threshold at 7 day follow-up. That definition tells readers what was intended to count as a response. Without the observed proportion and its denominator, however, it does not tell readers how often the criterion was met.

It also illustrates the importance of aligning the analysis unit with the statistical method. The endpoint is defined for eyes, while participants wore lenses bilaterally. If both eyes contribute measurements, their outcomes may be related because they come from the same participant. The record does not explain whether or how this dependence was handled. That methodological detail matters for the precision of an estimate, even though the registry entry does not permit an assessment of the actual analysis.

The single-arm design is another instructive feature. A descriptive evaluation can characterize the recorded experience with a prototype, but without a comparator it cannot estimate a randomized contrast. This distinction prevents a common interpretive leap from an outcome observed in one group to a claim about how that outcome compares with another option.

Finally, the record separates enrollment from the per-protocol analysis population and reports an exclusion for a major protocol deviation. Those details show why the number enrolled should not automatically be treated as the analysis denominator. The missing final analysis count and missing endpoint result leave readers unable to evaluate completeness, precision, or the influence of exclusions. For statistical interpretation, transparent reporting of denominators, estimates, uncertainty and analysis methods is as important as naming the outcome.

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 most important limitation for interpretation is that the registry record does not report the numerical primary endpoint result. It gives no observed proportion, endpoint denominator, confidence interval, or test result. The primary visual acuity finding therefore cannot be assessed for magnitude or precision.

The record lists enrollment of 177, but the primary analysis population is per-protocol and excludes one subject for a major protocol deviation. It does not state the final number of subjects or eyes analyzed. It also does not explain whether both eyes contributed data or how any within-participant relationship was handled. These missing details constrain evaluation of the endpoint's statistical precision.

The design is single-arm and non-randomized, with no comparator group listed. Accordingly, the record cannot support a randomized between-group comparison. The study's stated evaluation areas include visual acuity, rotational performance, lens fit, stability and subjective characteristics, but numerical results for those areas are not reported in the registry entry.

The registry describes the primary population but does not explain missing-data handling, sensitivity analyses, the statistical model, uncertainty estimation, or multiplicity procedures. It also does not report a sample-size justification or interim analyses. Masking is unclear because the record lists “NONE” while its brief summary describes the study as single-masked; no clarification is given. Together, these limitations mean that the entry supports a description of design and intended measurement, but not a full statistical appraisal of outcome estimates.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Dispensing Evaluation of Investigational Contact Lenses — NCT02625220.
• Registry record last updated 2017-06-07; status last verified 2017-05.
• Results first posted 2017-06-07.
• 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

NCT02625220 is a completed, single-group dispensing evaluation of a prototype toric senofilcon A contact lens, sponsored by Johnson & Johnson Vision Care, Inc. The record lists enrollment of 177 and describes bilateral daily disposable wear for 6-8 days. Its primary endpoint is the proportion of subject eyes with monocular visual acuity of 20/40 or better at 7 day follow-up.

The primary analysis population is described as per-protocol, with one subject excluded for a major protocol deviation. The registry record does not report the numerical primary endpoint result, analysis denominator, or statistical analysis details. It records zero serious and zero other adverse events among 170 participants at risk in each category. The study has no comparator group, and the masking description is inconsistent within the record.