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 Clinical Evaluation of Stenfilcon A Soft Contact Lens When Compared to Ocufilcon B Soft Contact Lens (NCT01354223), a randomized na study. The primary outcome is Objective Assessment: Ocular Response - Biomicroscopy.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01354223 |
| Phase | NA |
| Condition | Myopia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 90 |
| Arms in the primary outcome | n/a |
| Lead sponsor | CooperVision, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned people with myopia. The registry lists an enrollment of 90. The primary endpoint describes its population in terms of unique eyes: each individual eye was counted once for each visit grouping. Participant characteristics beyond the condition are not reported in the registry record.
Intervention
Participants were randomized to stenfilcon A contact lenses, worn in daily-wear, daily-disposable mode. The study’s stated purpose was to evaluate this lens against an existing daily disposable lens.
Comparator
The comparison group was randomized to ocufilcon B contact lenses, also worn in daily-wear, daily-disposable mode. The registry does not report additional details about lens fitting or participant instructions.
Primary question
The primary safety question was whether objective slit-lamp findings, assessed by biomicroscopy, differed between lenses. The endpoint used the highest reported grade over the study for each unique eye, then compared average grades among eyes with findings greater than 0 (none). Numerical findings for this comparison are not reported in the registry record.
3. Trial Design
The registry describes a randomized, parallel-group study with no masking. One group received stenfilcon A and the other received ocufilcon B, with both lenses used in daily-wear, daily-disposable mode. The record lists an enrollment of 90 and a status of completed. It identifies the study as not applicable for phase. The sponsor is CooperVision, Inc.
The recorded study start is 2010-10, and primary completion is recorded as 2011-03. These registry dates describe the study record; they do not provide the duration of lens use for each participant. The primary endpoint timeframe is described as change from baseline visit and all follow-up visits. Follow-ups are identified as week 1, week 2, month 1, and month 2, combined for the analysis described in the endpoint text.
Random allocation is intended, in general, to reduce systematic differences between treatment groups at assignment. A parallel design assigns participants to one group rather than having each participant receive both interventions. Because masking is listed as none, the record does not describe blinding. It does not report who knew the assigned lens or whether outcome assessors were masked. The randomization procedure, allocation concealment, eligibility details, and participant flow are not reported in the registry record.
The record lists five outcome measures and no analysis entries. It identifies comfort without symptoms of discomfort and average daily hours worn as secondary outcomes. Their numerical results are not reported in the registry record. The primary endpoint is described, but the registry does not provide the group estimates or a statistical comparison for it.
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: Ninety-three subjects evaluated, 3 subjects found to be ineligible and not randomized or dispensed. 90 adapted single-vision contact lens wearers with myopia were randomized and dispensed on a 2 to 1 ratio within each site and across entire study. Subjects used that same assigned product throughout study duration
Overall Study
| Stage | Stenfilcon A Contact Lens | Ocufilcon B Contact Lens |
|---|---|---|
| STARTED | 60 | 30 |
| COMPLETED | 57 | 29 |
| NOT COMPLETED | 3 | 1 |
Reasons for not completing this period:
| Reason | Stenfilcon A Contact Lens | Ocufilcon B Contact Lens |
|---|---|---|
| Withdrawal by Subject | 3 | 1 |
Analysis population for the primary outcome, as defined in the registry: Unique eyes are defined as each individual eye in the study and are only counted once for each of the visit groupings
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.
| Characteristic | Unit | Stenfilcon A Contact Lens | Ocufilcon B Contact Lens | Total |
|---|---|---|---|---|
| Participants analysed | 60 | 30 | 90 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 60 | 30 | 90 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 32.6 (SD 8.884) | 29.8 (SD 8.550) | 31.7 (SD 8.822) |
| Sex: Female, Male: Female | Participants | 38 | 21 | 59 |
| Sex: Female, Male: Male | Participants | 22 | 9 | 31 |
| Region of Enrollment: United States | participants | 60 | 30 | 90 |
6. Primary Endpoint
The registry lists the primary outcome as Objective Assessment: Ocular Response - Biomicroscopy, measured over Change from baseline visit and all follow-ups visits.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | units on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint concerns objective ocular response assessed by biomicroscopy, a slit-lamp examination measure. The registry describes findings graded on a scale where 0=not present and 4=severe. For each unique eye, the highest reported grade over the study duration was selected. The stated comparison then considered the average grade among unique eyes with findings greater than 0 (none). Eyes were counted once within each visit grouping.
The record distinguishes baseline from the combined follow-up visits: week 1, week 2, month 1, and month 2. The timeframe is described as change from baseline and all follow-ups, but the endpoint description does not provide a numerical change estimate, a group mean, or a measure of uncertainty. Although the outcome field describes the parameter as a mean and dispersion as full range, the registry record does not report the endpoint values.
Biomicroscopy is used as an objective safety assessment: it records observable ocular findings rather than relying only on a participant’s subjective experience. The general statistical rationale for reporting a mean is to describe the average grade within the defined group of eyes. The full range can show the spread from the lowest to the highest observed value, but the range alone does not show how observations are distributed between those extremes. Without reported values, neither the average nor the range can be interpreted for this comparison.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies an objective safety endpoint and describes how grades were selected and summarized, but it does not report the endpoint results. There are no posted group means, ranges, changes from baseline, confidence intervals, or p-values for the biomicroscopy comparison. Consequently, the direction, size, and precision of any group difference cannot be assessed from the registry record.
The endpoint is not a simple count of all examination findings. The description selects the highest grade for each unique eye over the study duration and then compares average grades among eyes with findings greater than 0 (none). The approach therefore focuses on the most severe recorded grade for each eye in the specified visit grouping, conditional on a finding being present. It does not, by itself, describe how often findings occurred among all eyes, nor does it show the full time course of each finding.
The wording about change from baseline and all follow-up visits is not accompanied by numerical estimates or a detailed model. It is not reported in the registry record whether the comparison adjusted for baseline grades, accounted for correlation between eyes from the same participant, or used another adjustment. The record also does not explain how missing examination measurements were handled. These details matter when interpreting estimates, but no estimate is available to qualify.
The posted safety counts report 0 serious adverse events in the stenfilcon A group, with 60 at risk, and 0 in the ocufilcon B group, with 30 at risk. Other adverse events are recorded as 3 and 0, respectively, with the same group-specific at-risk counts. These are descriptive registry counts. The record does not identify the other events or provide a statistical comparison, so they cannot establish the relative frequency or nature of harms.
The study’s randomization is relevant to the intended comparison, but random allocation alone does not supply evidence about the result. Interpretation requires the outcome estimates and information about uncertainty and analysis choices. Since the primary outcome has several categories or time points and is not reduced to one comparison in the registry record, a single primary-effect summary cannot be reconstructed from this entry. No treatment conclusion follows from the design description or the safety counts alone.
9. Statistical Methods Explained
The methods described in the registry are limited. It identifies the study as randomized, parallel, and unmasked, and gives a descriptive endpoint definition. It does not report the statistical analysis used for the primary endpoint. The explanations below describe general statistical principles, not methods confirmed to have been used in this trial.
What does randomization contribute?
In general, randomization assigns participants by chance to study groups. This can help balance measured and unmeasured participant characteristics across groups on average, reducing the risk that group differences are caused by systematic allocation choices. Randomization does not guarantee identical groups, and it does not ensure that missing data, departures from assigned treatment, or outcome assessment are unbiased. The registry does not report the sequence-generation method or allocation concealment, so those aspects cannot be evaluated.
What does a parallel design mean?
In a parallel design, groups receive different interventions during the comparison rather than switching interventions within the same participant. The lens groups in this study are described as stenfilcon A and ocufilcon B. In general, analysis of a parallel-group trial compares outcomes between assigned groups. The record does not state whether the primary analysis followed assigned groups regardless of lens use, or whether it used another analysis population.
How should a mean grade be understood?
A mean is a measure of the average value in a defined set of observations. Here, the endpoint description first selects a highest grade for each unique eye and then describes an average among eyes with findings greater than 0 (none). Because the analysis is restricted to eyes with findings, this average describes severity among that subset; it is not the proportion of all eyes with a finding. In general, it is useful to distinguish the occurrence of an outcome from its severity among those experiencing it.
The grade scale runs from 0=not present to 4=severe. The registry reports the dispersion type as full range. In general, a range records the lowest and highest observed values and is sensitive to extreme observations. It does not show the frequency of each grade or how concentrated observations are around the mean. The registry does not provide the actual range or mean values.
Why does dependence between eyes matter?
General statistical methods often assume that observations are independent. Two eyes from one participant may share characteristics, so their measurements can be correlated. Treating correlated eye measurements as independent can make uncertainty appear smaller than it is. The endpoint defines unique eyes and says each is counted once for a visit grouping, but the registry does not report whether both eyes could contribute for a participant or how any within-participant correlation was handled.
What would a confidence interval communicate?
In general, a confidence interval describes the range of values compatible with an estimate under a specified statistical procedure and its assumptions. It communicates uncertainty about the estimated group difference; it does not guarantee that the true value lies inside the interval, and it is not a probability statement about a particular result. No confidence interval or effect estimate for the primary endpoint is reported in the registry record. A p-value, if reported, would address a different question and would not convey the size or clinical importance of an effect on its own.
What do the planning assumptions mean?
The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power, and do not describe the trial’s actual design justification. The registry does not report the sample-size justification. No planning estimates are reported in the registry record, and the primary outcome is not reduced to one comparison for this purpose.
10. Multiplicity, Missing Data and Analysis Populations
The primary endpoint description includes multiple findings and visit groupings. The registry says the highest reported grade over the study duration was selected for each unique eye, and that follow-up visits were combined. It does not report a multiplicity strategy, such as how the analysis handled testing across different biomicroscopy findings or other outcomes. Without that information and without outcome-specific estimates, the false-positive risk across multiple comparisons cannot be assessed. The record does not report interim analyses.
Five outcome measures are listed, including the primary biomicroscopy endpoint and secondary outcomes for comfort without symptoms of discomfort and average daily hours worn. The other outcome measures are not named in the registry record. Numerical results for the listed secondary outcomes are also not reported. The record contains no analysis entries, and it does not explain whether all planned outcomes were analyzed or how results were selected for reporting.
Missing-data methods and analysis populations are not reported in the registry record. It is therefore unclear how incomplete examinations, missed visits, or participants who did not follow their assigned lens use were handled. The endpoint definition refers to unique eyes, but this does not establish how many eyes or participants contributed to each analysis or whether the analysis accounted for eyes within the same participant.
These omissions constrain interpretation rather than proving that a particular method was or was not used. A complete analysis description would ordinarily clarify the population included, the handling of missing measurements, the comparison model, and any adjustment for multiple testing. Those details cannot be inferred from the endpoint description 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 |
|---|---|---|---|
| Stenfilcon A Contact Lens | 0 | 60 | 0.0% |
| Ocufilcon B Contact Lens | 0 | 30 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Stenfilcon A Contact Lens | 3 of 60 |
| Ocufilcon B Contact Lens | 0 of 30 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Stenfilcon A Contact Lens | Ocufilcon B Contact Lens |
|---|---|---|---|
| Papillary Conjunctivitis | Eye disorders | 3 of 60 | 0 of 30 |
The registry reports no serious adverse events in either group: 0 affected among 60 at risk in the stenfilcon A group, and 0 affected among 30 at risk in the ocufilcon B group. It also reports 3 other adverse events among 60 at risk in the stenfilcon A group and 0 among 30 at risk in the ocufilcon B group. These are the recorded counts; the registry does not provide event descriptions for the other adverse events.
Counts should be read as descriptive entries, not as a complete comparison of safety. The record does not report a statistical analysis, uncertainty estimates, severity details for the other events, or whether the counts refer to unique participants or event episodes. Deaths are not reported in the registry record. Zero recorded serious events does not establish that serious events were impossible or that the groups had equivalent safety; it describes only what this registry entry reports.
12. What the Result Does, and Does Not, Mean
This trial record documents a randomized comparison of two daily disposable contact lenses and defines an objective biomicroscopy safety endpoint. It also records serious and other adverse-event counts. Those features help identify the clinical question and the type of evidence the study was designed to collect.
However, the registry does not report numerical results for the primary endpoint. It therefore does not establish whether the average grades differed between groups, how large any difference was, or how precise an estimate might be. There are no reported confidence intervals or p-values to support an inference about the primary comparison. The absence of posted outcome values is not evidence that the groups had identical outcomes.
The adverse-event figures are limited descriptive counts. The record reports 0 serious adverse events in both groups and 3 other adverse events in the stenfilcon A group versus 0 in the ocufilcon B group. Event descriptions and a comparative analysis are absent. These figures alone cannot establish a treatment effect or explain the clinical significance of the events.
In general, a trial result is interpreted by considering the outcome definition, the size and uncertainty of the comparison, how participants and measurements were analyzed, and the limits of the study design. For this record, the endpoint description is available, but the estimates and several analysis details are not. The registry entry therefore supports a description of the intended comparison and recorded safety counts, not a conclusion about which lens had better outcomes or whether either lens works or does not work.
13. Why This Trial Matters Statistically
The study illustrates why an outcome definition is important to statistical interpretation. Its primary safety endpoint is not simply the number of findings. It uses the highest grade for each unique eye and then averages grades among eyes with findings greater than 0 (none). That distinction changes the question being summarized: severity among eyes with findings is different from the occurrence of findings across all eyes.
The record also makes clear that analysis units need careful definition. The endpoint is described in terms of eyes, while randomization is described at the participant level. In general, when more than one eye per participant can contribute, observations may be related. Statistical methods need to account for that dependence if it is present. The registry defines unique eyes but does not say how any dependence was handled.
Another statistical lesson is that a clearly named endpoint does not substitute for results. Without group estimates and uncertainty measures, the direction and precision of the primary comparison cannot be evaluated. Likewise, the reported safety counts cannot show whether an observed difference is meaningful or compatible with chance. Transparent reporting of methods and numerical estimates is needed to move from a study question to an interpretable result.
The record’s description of multiple findings, visit groupings, and additional outcomes also highlights the value of prespecified analysis plans and clear multiplicity reporting. Those details are not reported in the registry record. This limits the reader’s ability to understand how the primary comparison relates to the broader set of outcomes.
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.
Several trial-specific limitations of interpretation follow from the registry entry. First, the primary endpoint has no reported numerical results. No group averages, ranges, changes from baseline, or uncertainty estimates are available, so the primary comparison cannot be evaluated quantitatively.
Second, the endpoint description combines follow-up visits and selects the highest reported grade for each unique eye. This defines a particular summary but does not show the progression of findings over time. The record does not report results for individual visits or explain whether baseline values were incorporated through adjustment or another method.
Third, the analysis is defined for eyes with findings greater than 0 (none). The registry does not report how many eyes met that condition, the distribution of grades, or the frequency of findings among all eyes. It also does not clarify whether both eyes from a participant could be included or how within-participant dependence was addressed.
Fourth, the study is unmasked according to the registry. The record does not identify whether examiners were masked, which leaves that aspect of outcome assessment unclear. Details of randomization, allocation concealment, eligibility, participant flow, adherence, and missing-data handling are not reported in the registry record.
Finally, the adverse-event entries do not identify the other events or provide a comparative analysis, and deaths are not reported in the registry record. The number of outcome measures is listed, but the complete outcome set and multiplicity approach are not described. These gaps limit assessment of the completeness and precision of the evidence in the registry entry.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Clinical Evaluation of Stenfilcon A Soft Contact Lens When Compared to Ocufilcon B Soft Contact Lens — NCT01354223.
- Registry record last updated 2020-07-29; status last verified 2020-07.
- Results first posted 2014-03-21.
- 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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Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The record describes a completed, randomized, parallel, unmasked study of stenfilcon A versus ocufilcon B contact lenses for daily wear in a daily-disposable mode. It lists myopia as the condition, enrollment of 90, and CooperVision, Inc. as sponsor. The recorded study dates are 2010-10 for start and 2011-03 for primary completion.
The primary safety endpoint is objective ocular response assessed by biomicroscopy. Its description uses the highest grade per unique eye and compares average grades among eyes with findings greater than 0 (none). The registry record does not report numerical results for this endpoint. It lists five outcome measures and no analysis entries.
The safety record reports 0 serious adverse events in each group and other adverse-event counts of 3 for stenfilcon A and 0 for ocufilcon B. Numerical results for secondary outcomes and further event details are not reported in the registry record. The entry supports a description of the trial design and outcome definitions, but not a quantitative conclusion about the primary comparison.