This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Initial Performance of a Modified Daily Disposable Contact Lens (NCT02694835), a randomized na study. The primary outcome is Incidence (Number) of Ocular Discomfort Device-related Adverse Events (AEs).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02694835 |
| Phase | NA |
| Condition | Refractive Error |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 81 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Alcon Research |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned people with refractive error who wore study contact lenses bilaterally. The registry record reports enrollment of 81 and identifies the Full Analysis Set as the primary endpoint population. Arm counts are recorded as 41 for DT1 UV and 39 for Dailies Total1 (DT1); the registry record does not explain the relationship between the overall enrollment and those arm counts.
Intervention
The intervention was delefilcon A contact lenses with an ultraviolet absorber, identified as DT1 UV. The arm description says the lenses were worn in both eyes for 9 hours.
Comparator
The comparator was delefilcon A contact lenses identified as Dailies Total1 (DT1), without the ultraviolet absorber named for the intervention. The comparator lenses were also worn in both eyes for 9 hours.
Primary question
The primary question was whether the arms differed in the incidence, recorded as the number of eyes with ocular discomfort device-related adverse events at Day 1 at Hour 9 ± 3 hours. The registry record reports 0 events in each arm. It does not post an analysis estimating the difference between arms or its uncertainty.
This is a comparison of short-term event counts following lens wear, not a report of long-term outcomes or a comprehensive assessment of contact lens performance. The record defines an adverse event as an untoward medical occurrence in a subject administered study treatment, whether or not the event was causally related to treatment. The endpoint therefore concerns recorded events under that definition; it does not, by itself, establish that a lens caused or prevented discomfort.
3. Trial Design
The registry describes a randomized, double-masked, parallel-group device study. Participants were assigned to DT1 UV or Dailies Total1 (DT1), and the two arms used distinct delefilcon A lens descriptions. The intervention lens included an ultraviolet absorber; the comparator description does not. Both arms wore the lenses bilaterally for 9 hours. The registry lists the study phase as not applicable.
Enrollment is recorded as 81. The arm-level outcome entries list 41 for DT1 UV and 39 for Dailies Total1 (DT1). The endpoint describes the analysis population as the Full Analysis Set, but the registry record does not define how that set was formed or reconcile its arm counts with the enrollment figure. The unit for the primary outcome is eyes, while the lens-wear descriptions refer to bilateral wear. The eye-level unit and the participant-level assignment are therefore important to keep distinct when interpreting the reported counts.
The primary completion date is recorded as 2016-04-11, and the overall status is completed. The endpoint timeframe is Day 1 at Hour 9 ± 3 hours. The registry record does not report further details about visit procedures, the sequence used to generate assignments, allocation concealment, or which study personnel were masked. The label double-masked indicates the reported masking category, but additional operational details are not reported in the registry record.
The design provides a randomized comparison between the two lens groups at the specified assessment. Randomization can support a fair comparison when implemented and analyzed appropriately, but the record does not include enough detail to assess those procedures. It also does not post an inferential comparison for the primary endpoint. Consequently, the design description alone cannot establish whether any between-arm difference was statistically distinguishable from random variation.
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 81 enrolled, 1 subject exited as a screen failure prior to randomization. This reporting group includes all randomized subjects (80).
Overall Study
| Stage | DT1 UV | Dailies Total1 (DT1) |
|---|---|---|
| STARTED | 41 | 39 |
| COMPLETED | 41 | 39 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Full 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: This analysis population includes all randomized subjects who were exposed to the investigational product and satisfied specific evaluability criteria (Full Analysis Set).
| Characteristic | Unit | DT1 UV | Dailies Total1 (DT1) | Total |
|---|---|---|---|---|
| Participants analysed | 41 | 39 | 80 | |
| Age, Continuous | years | 36.2 (SD 8.5) | 35.3 (SD 9.9) | 35.8 (SD 9.2) |
| Sex: Female, Male: Female | Participants | 34 | 23 | 57 |
| Sex: Female, Male: Male | Participants | 7 | 16 | 23 |
| Race/Ethnicity, Customized: White | Participants | 36 | 35 | 71 |
| Race/Ethnicity, Customized: Black or African American | Participants | 2 | 0 | 2 |
| Race/Ethnicity, Customized: American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race/Ethnicity, Customized: Asian | Participants | 3 | 2 | 5 |
| Race/Ethnicity, Customized: Native Hawaiian or Other Pacific Island | Participants | 0 | 0 | 0 |
| Race/Ethnicity, Customized: Multi-Racial | Participants | 0 | 0 | 0 |
| Race/Ethnicity, Customized: Other | Participants | 0 | 2 | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Incidence (Number) of Ocular Discomfort Device-related Adverse Events (AEs), measured over Day 1 at Hour 9 ± 3 hours.
| Element | Registry entry |
|---|---|
| Result type | Count Of Units |
| Measure of spread | not applicable |
| Unit | Eyes |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the incidence, expressed as a number, of ocular discomfort device-related adverse events. The result is recorded in eyes, and the assessment time is Day 1 at Hour 9 ± 3 hours. The registry definition of an adverse event is broad: any untoward medical occurrence in a subject administered study treatment qualifies, whether or not it has a causal relationship with treatment. The record identifies the Full Analysis Set as the endpoint population.
An event-count endpoint can describe how many units experienced an event during the stated assessment period. Here, the posted arm values are counts of 0 for DT1 UV and 0 for Dailies Total1 (DT1), with the corresponding arm denominators recorded as 41 and 39. These counts describe what was recorded at the endpoint; they do not characterize the severity of discomfort, its duration, or symptoms that did not meet the adverse-event definition.
The endpoint is relevant to the study’s stated purpose of evaluating ocular discomfort device-related adverse events after lens wear. It offers a concrete safety and tolerability measure at the scheduled assessment. However, an event count is not a complete measure of comfort or overall lens performance. The registry record does not report a separate discomfort rating scale, a broader patient-reported outcome, or a longer-term assessment. It also does not explain how eye-level outcomes were handled statistically when each participant wore lenses in both eyes.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry reports 0 ocular discomfort device-related adverse events in the DT1 UV arm and 0 in the Dailies Total1 (DT1) arm at Day 1 at Hour 9 ± 3 hours. The reported denominators are 41 and 39, respectively. This is a descriptive finding for the endpoint and assessment recorded. It does not mean that every participant experienced no discomfort of any kind, because the endpoint counts adverse events under the registry definition rather than every sensation or symptom.
No primary statistical analysis is posted. The record lists zero posted analyses, and it does not report a test statistic, p-value, confidence interval, adjusted estimate, or other inferential result for the arm comparison. The registry’s outcome entry also notes that values were missing or not estimable for a two-arm comparison for this count-other endpoint. Therefore, the counts can be described, but a registry-based estimate of the size and precision of a between-arm effect cannot be presented.
When an event is not observed in either arm, the observed data contain little direct information about how the arms might differ in the event rate outside this particular assessment. A zero count is not proof that the underlying event probability is zero. General statistical explanation: estimates based on sparse or absent events can have substantial uncertainty, and different analytical approaches may produce different interval estimates. No interval estimate is reported in the registry record, so the uncertainty cannot be quantified from the posted result.
The recorded counts do not establish that the lenses are equivalent, that one is noninferior to the other, or that either prevents ocular discomfort. Those conclusions require a prespecified comparison framework and an analysis that accounts for uncertainty. The registry record does not report an equivalence or noninferiority margin, a formal hypothesis test, or an inferential analysis for this outcome. The reported lack of events should therefore be interpreted narrowly as a description of the observations entered for this endpoint and timeframe.
The eye is the stated outcome unit, whereas treatment assignment and lens wear are described at the participant level, with both eyes exposed. General statistical explanation: outcomes from two eyes of the same person may be correlated, so treating every eye as statistically independent can understate uncertainty if that correlation is ignored. The registry record does not report whether the analysis accounted for within-participant correlation. This is an additional reason not to infer comparative precision from the raw counts alone.
The record’s enrollment and arm counts provide context for the amount of observed information, but they do not substitute for an uncertainty estimate. The result applies to the stated endpoint population and assessment, not automatically to other lenses, exposure periods, populations, or outcomes. No conclusion about longer-term tolerability can be drawn from this single reported assessment.
9. Statistical Methods Explained
The primary outcome is an event count, reported in eyes, rather than a continuous measurement such as a score or a time-to-event outcome. The registry describes the parameter as a count of units and gives the endpoint title as the incidence, or number, of ocular discomfort device-related adverse events. The posted values are counts of 0 in both arms. No dispersion measure or confidence limits are posted, and the record does not give an inferential model for these counts.
What does a count comparison estimate?
General statistical explanation: a count comparison may focus on the number of events, the proportion of units with at least one event, or an event rate relative to exposure. These are related but not identical targets. A proportion requires a clearly defined denominator of units at risk; an event rate also depends on the amount of time or exposure observed. The registry gives eye denominators for the posted outcome, but it does not report an exposure-adjusted rate or explain whether multiple events in one eye could be counted separately. The endpoint label and definition should therefore guide interpretation: the posted result is an event count, not a reported rate ratio or risk difference.
Why can zero counts limit inference?
General statistical explanation: when few or no events are observed, the data may not support a stable estimate of a relative effect. Methods that rely on approximations can behave poorly with sparse counts, and some relative measures may be undefined when event counts are zero in both groups. Other approaches can estimate uncertainty, but they require explicit modeling choices and assumptions. The registry record does not identify an analysis method or provide estimates from such methods. No new comparison estimate should be inferred from the two zero counts.
Over-dispersion is a general concern for count data. It occurs when observed variability exceeds what a simple count model assumes, potentially because observations differ in their underlying event risk or because events cluster. If a model fails to account for over-dispersion, its uncertainty estimates may be too narrow. The registry record does not report a count model, an assessment of over-dispersion, or a correction for it. This is a methodological consideration, not evidence that over-dispersion occurred in this study.
How does bilateral eye measurement matter?
General statistical explanation: when each participant contributes outcomes from both eyes, the two eye-level observations may be more alike than observations from different participants. This within-person correlation affects the effective information available for an eye-level comparison. Analyses can address clustering by participant, or they can define a participant-level outcome, but these choices answer questions in different ways and require prespecified methods. The endpoint is recorded in eyes and the arms are described as bilateral wear. The registry record does not report whether both eyes were included for every participant, how eye-level data were aggregated, or how dependence between eyes was handled.
What can the posted analysis tell us?
The registry outcome entry says that values were missing or not estimable for a two-arm comparison, and the record reports no posted analyses. Thus, the available results are descriptive arm counts rather than a sponsor-reported hypothesis test or effect estimate. A confidence interval would ordinarily communicate a range of effect sizes compatible with the data under a specified method. No such interval is reported. A p-value, if calculated under a stated test, would address compatibility with a null hypothesis; it would not by itself describe the magnitude or practical importance of a difference. No p-value is reported for this endpoint.
The sample-size assumptions recorded for planning illustrations are a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. These are planning assumptions, not a report of the trial’s statistical analysis plan. The record does not report the trial’s own sample-size justification or its planned analysis. Any sample-size illustration based on an observed effect is a planning exercise rather than observed power; it cannot repair the absence of an inferential analysis, and it should not be read as evidence that the study had a particular probability of detecting an effect.
Random allocation and masking are design features, not analysis methods. They can reduce some sources of bias when appropriately implemented, but neither removes the need to define the estimand, account for the eye-level structure, handle missing observations, and report uncertainty. The registry record describes the design as randomized, double-masked, and parallel, but it does not report the analytical details needed to evaluate those issues.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome measure and no posted secondary outcomes. With only one listed outcome, the record does not present a family of multiple posted endpoints for which a multiplicity adjustment can be evaluated. However, the statistical plan is not reported in the registry record, so it is not possible to determine whether additional outcomes, timepoints, subgroup analyses, or interim looks were planned or considered. The record does not report an adjustment method, a hierarchy of hypotheses, or an interim-analysis plan.
The primary outcome population is identified as the Full Analysis Set, but the record does not define the set, state the inclusion rules, or explain how participants with incomplete endpoint data were handled. Missing-data counts and reasons are not reported in the registry record. It is therefore not possible to assess whether all randomized participants contributed to the outcome, whether exclusions occurred, or whether missingness could have affected the comparison.
Enrollment is recorded as 81, while the arm entries list 41 for DT1 UV and 39 for Dailies Total1 (DT1). The record does not explain the relationship among enrollment, arm denominators, and the Full Analysis Set. In addition, the endpoint is reported in eyes, while the lenses were worn bilaterally. The record does not state how missing information for one eye, if any, was handled or whether both eyes contributed for each participant.
These omissions matter because analysis-population definitions, missing-data handling, and multiplicity decisions can affect the interpretation of a comparative result. They cannot be resolved from the posted counts alone.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| DT1 UV | 0 | 41 | 0.0% |
| Dailies Total1 (DT1) | 0 | 39 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| DT1 UV | 0 of 41 |
| Dailies Total1 (DT1) | 0 of 39 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| DT1 UV | 0 of 41 |
| Dailies Total1 (DT1) | 0 of 39 |
The serious adverse event entries report 0 serious events among 41 at-risk units for DT1 UV and 0 among 39 at-risk units for Dailies Total1 (DT1). The death counts are also 0 in both arms. The other adverse event counts are recorded as 0 in each arm. No serious adverse event terms are listed.
These entries describe the events recorded in the registry; they are not a guarantee that an event is impossible or that risk is absent. General statistical explanation: with no observed events, the underlying risk remains uncertain, and the amount of uncertainty depends on the amount and structure of follow-up as well as the method used to estimate it. The registry record does not report confidence intervals for these safety figures.
The primary endpoint concerns ocular discomfort device-related adverse events at Day 1 at Hour 9 ± 3 hours. The adverse-event definition includes untoward medical occurrences regardless of whether they were judged causally related to treatment. The serious-event figures should be read within the scope of the safety reporting and follow-up described in the record, not as evidence about unreported outcomes or longer periods of use.
12. What the Result Does, and Does Not, Mean
The central descriptive result is that the registry records 0 ocular discomfort device-related adverse events in each arm at Day 1 at Hour 9 ± 3 hours. The endpoint is defined broadly as an untoward medical occurrence in a treated subject, regardless of whether it is considered related to treatment. The result is limited to that definition, the Full Analysis Set designation, and the reported assessment.
This finding does not establish that the two lenses have the same event risk. Equal observed counts are not a formal equivalence result, especially when no effect estimate, confidence interval, or hypothesis test is posted. An absence of observed events in the recorded assessment also does not establish zero underlying risk. The result does not prove that either lens prevents discomfort or that the ultraviolet absorber changes the likelihood of an event.
The record addresses a specific comparison: delefilcon A lenses with an ultraviolet absorber versus delefilcon A lenses without the absorber, each worn bilaterally for 9 hours. The primary assessment is on Day 1 at Hour 9 ± 3 hours. It does not answer questions about repeated or longer use, other contact lenses, other populations, or outcomes that were not reported. It also does not describe the frequency or intensity of ordinary sensations unless they were recorded as qualifying adverse events.
Randomization and double masking are reported design features that may support a fair comparison, but the record does not give implementation details or a statistical analysis of the primary endpoint. The outcome is recorded in eyes, and the record does not explain how the analysis addressed the possibility that two eyes from one participant are correlated. These limitations mean the posted counts are best treated as a narrowly scoped descriptive observation rather than a definitive comparative conclusion.
In short, the registry documents no recorded events in either arm for this endpoint and assessment. The magnitude and precision of any underlying difference remain unreported.
13. Why This Trial Matters Statistically
This trial illustrates a recurring statistical challenge: an endpoint can be clinically relevant and easy to describe, yet yield too little event information for a comparative estimate. When both arms have zero recorded events, the raw counts are straightforward, but they do not quantify the range of plausible differences between the groups. Reporting an uncertainty interval and explaining the analysis would help distinguish a precise estimate from a result that is simply sparse.
The study also highlights the importance of matching the statistical unit to the design. Treatment is assigned to participants, while the primary endpoint is recorded in eyes and both eyes are exposed. Eye-level data can carry within-person dependence. Clear reporting of the number of participants and eyes analyzed, the handling of incomplete eye data, and the method used to account for correlation is important for understanding precision.
Finally, a randomized and double-masked design is not a substitute for a transparent analysis plan. The registry record describes the design and outcome but does not report a statistical comparison, missing-data strategy, or sample-size justification. That leaves readers with a useful description of the observed event counts, but not a basis for judging comparative uncertainty. The distinction between a recorded zero and evidence of equivalence is particularly important in device studies with sparse adverse events.
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 primary endpoint is reported at a single assessment, Day 1 at Hour 9 ± 3 hours, after the arm descriptions specify 9 hours of bilateral wear. This supports interpretation of the recorded short-term assessment only; the registry record does not provide longer-term outcome data for this endpoint. The result cannot characterize how event counts might change with repeated or extended wear.
The primary result is an eye-level count, but the trial assigns lens groups at the participant level and describes both eyes as exposed. The registry does not report the number of eyes contributing to each participant’s result, whether both eyes were always analyzed, or how within-person correlation was handled. Eye-level denominators should therefore not be assumed to represent independent observations.
The event definition includes untoward medical occurrences whether or not causally related to treatment. The record does not give further criteria for classifying ocular discomfort events, details about ascertainment, or information about adjudication. These omissions limit assessment of how consistently the endpoint was identified across arms.
The arm counts and enrollment are not reconciled in the registry record, and the Full Analysis Set is not defined. Missing-data amounts and handling are not reported. No inferential analysis, confidence interval, or statistical plan is posted for the primary outcome. The record also does not report details of randomization implementation or masking procedures. These are reporting limitations; they do not establish that the procedures were inadequate, but they prevent independent evaluation of those aspects.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Initial Performance of a Modified Daily Disposable Contact Lens — NCT02694835.
- Registry record last updated 2019-03-13; status last verified 2019-02.
- Results first posted 2019-02-15.
- 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.
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18. Record Summary
NCT02694835 is a completed, randomized, double-masked, parallel-group device study sponsored by Alcon Research. It compared delefilcon A contact lenses with an ultraviolet absorber, DT1 UV, against Dailies Total1 (DT1). Both arms were described as bilateral lens wear for 9 hours. The study concerns refractive error, and enrollment is recorded as 81.
The primary outcome was the number of eyes with ocular discomfort device-related adverse events in the Full Analysis Set at Day 1 at Hour 9 ± 3 hours. The registry reports 0 events for DT1 UV, with an arm count of 41, and 0 for Dailies Total1 (DT1), with an arm count of 39. The outcome entry does not provide an estimable two-arm comparison, and no statistical analyses are posted.
The registry also records 0 serious adverse events and 0 deaths in each arm. It does not report a statistical analysis plan, missing-data handling, or an inferential estimate for the primary outcome. The posted results are descriptive and apply to the reported endpoint and assessment.