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 Determination of Cell Population in Solution-Induced Corneal Staining (SICS) and Symptomatic Versus Asymptomatic Lens Wearers (NCT01629706), a randomized na study. The primary outcome is Mean Number of Viable Epithelial Cells Collected Directly From the Ocular Surface After 2 Hours and 4 Hours of Wear, Phase 1.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01629706 |
| Phase | NA |
| Condition | Refractive Error, Dry Eye |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | Triple |
| Enrollment | 92 |
| Arms in the primary outcome | n/a |
| Lead sponsor | CIBA VISION |
| Results posted | Yes |
2. Clinical Question
Population
Phase 1 included participants who completed that phase with expected in-range responses. Phase 2 concerned habitual contact lens wearers, with the study’s stated aim including comparison of symptomatic and asymptomatic wearers. The record does not report the criteria used to classify symptoms or the number of participants in each symptom group.
Intervention
In Phase 1, a Balafilcon A contact lens pre-soaked overnight in ClearCare was worn in one eye for two hours and four hours on separate days. Phase 2 involved habitual contact lenses worn bilaterally on a daily wear basis for four weeks with habitual lens care.
Comparator
For Phase 1, the fellow eye wore a Balafilcon A lens pre-soaked overnight in Renu multi-purpose solution. Phase 2 describes habitual lenses and habitual care; the record does not specify a separate intervention comparator for that phase.
Primary question
In Phase 1, how many viable epithelial cells could be collected from the ocular surface after lens wear, at the specified wear durations? The study also aimed to examine cell appearance in symptomatic versus asymptomatic contact lens wearers, but that is not the named primary endpoint.
The registry describes the study as randomized and triple-masked, while also classifying its model as single group. It does not explain how randomization or masking was implemented, or how those design labels relate to the two phases. The primary endpoint concerns a measured cellular response, not a patient-reported symptom outcome. A numerical comparison of the Phase 1 regimens cannot be interpreted from this record because endpoint values and an inferential analysis are not reported in the registry record. The study’s stated aims provide context for the measurements, but do not by themselves establish a difference between regimens or between symptom groups.
3. Trial Design
The registry identifies NCT01629706 as a completed study sponsored by CIBA VISION. It lists an enrollment of 92, describes allocation as randomized, and describes masking as triple. The phase is recorded as not applicable. The study started in 2012-09, and primary completion was in 2014-01. The record lists refractive error and dry eye as conditions.
The study has two described phases. Phase 1 focused on solution-induced corneal staining and the corneal epithelial cell response associated with lens wear. Its arm description uses a within-participant, fellow-eye arrangement: one eye wore a Balafilcon A lens soaked overnight in ClearCare, and the fellow eye wore a Balafilcon A lens soaked overnight in Renu multi-purpose solution. The two-hour and four-hour wear assessments occurred on separate days. Cells from the right and left eyes were analyzed separately.
Phase 2 is described as habitual contact lenses worn bilaterally on a daily wear basis for four weeks with habitual lens care. Its stated purpose included determining cell appearance in symptomatic and asymptomatic contact lens wearers. The registry’s arm description identifies a habitual-wear group, but does not provide further details about symptom-group assignment or the comparison method.
There is a design-label ambiguity worth keeping in view: the registry calls the model single group, while the Phase 1 description specifies different care-solution conditions in fellow eyes and the Phase 2 aim refers to symptom groups. The record does not explain this classification. It also does not report the randomization sequence, masking roles, sample-size justification, or statistical analysis plan. Those details should not be inferred from the design labels alone.
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 92 unique participants were enrolled in the study, 44 in Phase 1 and 48 in Phase 2. Additionally, Phase 2 enrolled 10 participants from Phase 1, for a total of 58 participants in this Phase.
Phase 1 PureVision
| Stage | PureVision/Habitual |
|---|---|
| STARTED | 44 |
| COMPLETED | 35 |
| NOT COMPLETED | 9 |
Reasons for not completing this period:
| Reason | PureVision/Habitual |
|---|---|
| Screen Failure | 4 |
| Slit Lamp Finding prior to Dispense | 1 |
| Inconvenience prior to Dispense | 1 |
| No Solution-Induced Corneal Staining | 3 |
Phase 2 Habitual
| Stage | PureVision/Habitual |
|---|---|
| STARTED | 58 |
| COMPLETED | 48 |
| NOT COMPLETED | 10 |
Reasons for not completing this period:
| Reason | PureVision/Habitual |
|---|---|
| Screen Failure | 6 |
| Slit Lamp Finding prior to Dispense | 1 |
| Relocation prior to Dispense | 1 |
| Lost to Follow Up prior to Dispense | 1 |
| Lost to Follow Up after Dispense | 1 |
Analysis population for the primary outcome, as defined in the registry: This reporting group included all participants that completed Phase 1 of the study with expected in-range responses.
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 enrolled participants.
| Characteristic | Unit | Overall |
|---|---|---|
| Participants analysed | 92 | |
| Age, Continuous | years | 26.67 (SD 10.79) |
| Sex: Female, Male: Female | Participants | 69 |
| Sex: Female, Male: Male | Participants | 23 |
6. Primary Endpoint
The registry lists the primary outcome as Mean Number of Viable Epithelial Cells Collected Directly From the Ocular Surface After 2 Hours and 4 Hours of Wear, Phase 1, measured over Day 1 after 2 hours of wear; Day 7 after 4 hours of wear.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | cells |
| Endpoint classification | Continuous Endpoint |
The named primary endpoint is the mean number of viable epithelial cells collected directly from the ocular surface after two hours and four hours of lens wear in Phase 1. The registry specifies cells as the unit and standard deviation as the measure of dispersion. The collection procedure followed lens removal: an eyewash was used to collect corneal cells, samples were taken to a laboratory, live/dead stains were applied, and viable cells were counted with a microscope. Right-eye and left-eye samples were analyzed separately.
This endpoint quantifies a cellular measurement rather than relying on symptoms alone. In general, a mean describes the central value of a continuous measurement, while a standard deviation describes the spread of individual measurements around that mean. The record notes that a difference in viable cell count may indicate a physiological response to the lens and/or care regimen over time. That statement explains the endpoint’s rationale; it does not establish that a response occurred.
The specified time frame is Day 1 after two hours of wear and Day 7 after four hours of wear. The registry record does not report the actual mean cell counts, standard deviations, treatment contrasts, confidence intervals, or p-values. Consequently, the magnitude and precision of any observed difference cannot be assessed from the endpoint description.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record identifies a biologically measured primary endpoint, but does not report the numerical outcome values or a statistical comparison. It therefore does not establish whether viable epithelial cell counts differed between the ClearCare and Renu conditions, how large any difference was, or how precisely such a difference was estimated. The endpoint title alone is not a result.
The study’s measurement plan separates observations by eye and by specified wear duration. That distinction matters when interpreting results: an eye-specific value is not interchangeable with a participant-level summary, and a result at one wear duration should not automatically be taken to describe another duration. The record does not report a combined estimate across eyes or time points. Nor does it provide enough information to determine how any within-participant correlation was handled in an inferential analysis.
The Phase 2 objective concerns cell appearance among symptomatic and asymptomatic wearers, but the registry entries listed for the primary endpoint do not provide a Phase 2 numerical result. No symptom-group counts, measurements, contrasts, or uncertainty estimates are reported in the registry record. It is therefore not possible to judge the strength or precision of a symptom-group difference from this information.
The serious and other adverse event entries list zero affected participants in the PureVision group and zero in the Habitual group. These are the registry’s recorded counts for those categories and groups, not evidence that every possible adverse experience was absent. The death fields are not populated with counts, so deaths are not reported in the registry record. The event entries should be read separately from the primary cellular endpoint: they do not indicate what happened to viable cell counts or resolve the study’s efficacy-related research question.
Overall, the posted information supports a description of the study question, design labels, endpoint procedure, and recorded adverse-event counts. It does not support a conclusion about the direction or size of a primary endpoint effect, its statistical significance, or its precision. Any such conclusion would require outcome estimates and an analysis that are not reported in the registry record.
9. Statistical Methods Explained
The registry names a continuous primary outcome summarized as a mean, with standard deviation as the dispersion measure. In general, a mean is the arithmetic average of observed measurements. It gives a compact description of the center of a distribution, but does not show whether observations are tightly clustered or widely spread. A standard deviation describes that spread on the same measurement scale. Neither a mean nor a standard deviation, by itself, gives the estimated difference between conditions or uncertainty around that difference.
What does a mean cell count describe?
For this endpoint, the measured quantity is the number of viable cells collected from the ocular surface. A mean would describe the average count for the set of observations included in a defined group and measurement occasion. Interpretation depends on what observations were included: the record specifies that right and left eyes were analyzed separately, and identifies separate wear-duration occasions. A mean for one eye or occasion should not be treated as a pooled participant-level result unless the analysis explicitly defines it that way. That pooling method is not reported in the registry record.
Standard deviation is descriptive. It is not the same as a confidence interval and does not, on its own, quantify how precisely a group mean or contrast has been estimated. A confidence interval is a general statistical tool for expressing uncertainty in an estimate. Its width reflects both the observed variability and the amount of information available under the analysis. No confidence intervals for the primary endpoint are reported in the registry record.
How would a comparison be interpreted?
A treatment contrast would summarize how the cell-count outcome differs between the ClearCare and Renu conditions, under a specified analysis. For a paired or fellow-eye arrangement, a suitable analysis would generally need to account for the fact that measurements from two eyes of the same participant may be related. This is a general statistical consideration, not a claim about the method used in this study. The registry’s model label is single group, while its Phase 1 description assigns different solutions to fellow eyes. The record does not explain how the analysis accounted for that structure.
Statistical significance and clinical or biological importance are different ideas. A p-value, if reported, would describe how compatible the observed data are with a statistical null model under the assumptions of the test; it would not measure the size or importance of a difference. An effect estimate and its confidence interval would be needed to assess magnitude and precision. The primary endpoint’s estimates and inferential results are not reported in the registry record, so neither significance nor precision can be evaluated.
What does randomization and masking tell the reader?
The registry labels allocation randomized and masking triple. In general, random allocation can help make treatment groups comparable with respect to factors that could affect outcomes, while masking can reduce some forms of bias in treatment delivery, measurement, or assessment. These protections depend on implementation. The record does not report the randomization method, who was masked, how masking was maintained, or whether it could be assessed. The labels therefore describe the registered design but do not answer those operational questions.
How should planning calculations be read?
Sample-size illustrations based on an observed effect are planning exercises, not observed power for a completed study. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and detection of a stated fraction of the observed effect. For non-time-to-event outcomes, such illustrations are expressed as participants per arm for 80% power or for 90% power; time-to-event illustrations use total events. These assumptions describe the planning calculation, not the trial’s original design or analysis. The registry record does not report the sample-size justification used to design the study. Without the relevant observed effect estimates, the planning illustrations cannot be independently interpreted as evidence about the primary outcome.
The record lists zero analyses. That does not identify an analysis method; it indicates that an analysis is not reported in the registry record. No model specification, adjustment strategy, handling of repeated measurements, missing-data method, or multiplicity procedure is reported. General statistical principles can explain why those choices matter, but cannot substitute for the study’s undocumented analysis.
10. Multiplicity, Missing Data and Analysis Populations
The primary endpoint includes more than one measurement occasion and distinguishes the right and left eyes. The registry record also lists 11 outcome measures, but does not describe a multiplicity strategy. When several outcomes, time points, or subgroup comparisons are examined, the chance of at least one apparently unusual result can increase. In general, prespecified hypotheses and appropriate multiplicity methods help readers understand how to interpret a set of comparisons. The registry record does not report whether such methods were used.
The analysis population for the primary endpoint is described as participants who completed Phase 1 with expected in-range responses. This is not necessarily the same as all enrolled participants. The record does not define “expected in-range responses,” provide the number included in this population, or explain how exclusions were determined. It does not report whether participants with missing measurements were included in other analyses.
Missing-data handling is not reported in the registry record. In general, missing observations can affect estimates if the likelihood of missingness relates to treatment, participant characteristics, or outcomes. The record does not say whether missing values were imputed, excluded, or handled using another approach. No assumptions about the amount, causes, or impact of missing data can be made from the endpoint description.
The registry reports no analyses and does not provide a statistical analysis plan. It is therefore not possible to determine whether analyses were prespecified, how multiple eye and time-point measurements were handled, or how the Phase 2 symptom groups were analyzed. These omissions limit assessment of the robustness and completeness of the posted results.
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 |
|---|---|---|---|
| PureVision | 0 | 38 | 0.0% |
| Habitual | 0 | 49 | 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 |
|---|---|
| PureVision | 0 of 38 |
| Habitual | 0 of 49 |
The registry lists two adverse-event groups: PureVision and Habitual. For the PureVision group, 38 participants were listed as at risk for serious adverse events and 0 as affected; the other-adverse-event fields also list 38 at risk and 0 affected. For the Habitual group, 49 were listed as at risk for serious adverse events and 0 as affected; the other-adverse-event fields list 49 at risk and 0 affected.
These entries mean that the registry records zero participants affected in the listed serious and other adverse-event categories for these groups. They do not establish that no event of any kind occurred, and they do not describe events outside the recorded categories or reporting process. The death fields contain no reported counts; deaths are not reported in the registry record.
The at-risk counts are group-specific registry entries and should not be added together to infer a total number of participants. The adverse-event figures are also distinct from the primary endpoint, which concerns viable epithelial cell counts. They do not provide a treatment-effect estimate or uncertainty interval for that cellular outcome.
12. What the Result Does, and Does Not, Mean
This study’s stated purpose was to investigate the corneal epithelial cell response associated with lens wear resulting in solution-induced corneal staining in Phase 1, and to determine cell appearance among symptomatic and asymptomatic contact lens wearers in Phase 2. The named primary endpoint focuses on the number of viable cells collected after lens wear. These aims identify the questions the study was intended to address; they do not, by themselves, establish what the measurements showed.
The registry record describes different lens-care conditions in fellow eyes during Phase 1 and habitual lens wear during Phase 2. It also gives the measurement procedure and identifies the selected Phase 1 reporting population. But numerical primary endpoint values and an inferential analysis are not reported in the registry record. As a result, the posted information does not show whether cell counts differed by care solution, the size or direction of a difference, or the uncertainty around an estimate.
Likewise, the stated interest in symptomatic and asymptomatic wearers is not accompanied in this record by symptom-group results. The record does not report how symptoms were defined or whether the two groups differed in cell appearance. The primary endpoint should not be mistaken for a direct measure of symptoms: it is a laboratory count of viable cells collected from the ocular surface.
The adverse-event entries record zero affected participants in the serious and other categories for each listed group. Those counts should be understood within the registry’s reporting categories and should not be generalized to every possible event. The unreported death counts are not evidence of a particular death outcome.
In short, the record describes a completed study and its research questions, but does not provide the outcome statistics needed to judge the primary result. It cannot establish efficacy, lack of efficacy, or the magnitude or precision of a treatment difference. Nor can the design labels alone resolve the analysis choices or limitations.
13. Why This Trial Matters Statistically
This study is statistically interesting because its Phase 1 endpoint is a direct cellular measurement collected separately from the two eyes. Such measurements can raise analysis questions that are not resolved by reporting group means alone. In general, measurements from a participant’s two eyes may be correlated, and repeated observations can also be related. An analysis needs to reflect the actual assignment and measurement structure to produce interpretable estimates and uncertainty. The registry record does not report the analysis method.
The study also names different wear durations and includes a second phase with a distinct aim concerning symptomatic and asymptomatic wearers. Outcomes spread across eyes, time points, and groups can create multiple opportunities for comparison. Clear reporting of which comparisons were prespecified and how multiplicity was addressed helps readers distinguish a primary test from exploratory analyses. Those details are not reported in the registry record.
There is also a useful distinction between a detailed endpoint procedure and a complete statistical result. The record explains how cells were collected, stained, and counted, but does not report the resulting means, variability, contrasts, or uncertainty. Measurement detail helps clarify what the endpoint represents; it cannot replace estimates and an analysis when the question is whether conditions differed.
Finally, the record’s design labels and arm descriptions do not fully align on their face: it labels the model single group while describing randomized allocation and different fellow-eye conditions in Phase 1. The record does not explain this. Recognizing such reporting gaps is part of statistical interpretation, not a reason to guess at the study’s implementation. The record is most informative about its research aims and measurement process, and least informative about the primary endpoint’s numerical result.
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 what is and is not reported. First, the primary endpoint’s numerical means and standard deviations are absent, as are treatment contrasts, confidence intervals, and p-values. The direction, size, and precision of a Phase 1 difference therefore cannot be assessed. The record identifies multiple measurement occasions and separate eye analyses, but does not provide results for each.
Second, the registry labels the model single group while describing random allocation and different solution conditions in fellow eyes during Phase 1. It does not explain the relationship between those design features or specify the unit of randomization. The randomization procedure, masking roles, and analysis approach are also not reported. This restricts evaluation of how well the design and analysis match.
Third, the Phase 2 purpose refers to symptomatic and asymptomatic wearers, but the record does not report symptom definitions, group counts, or comparison results. The phase’s habitual-wear description does not supply those missing details. The Phase 1 reporting population is limited to participants completing the phase with expected in-range responses, but the meaning of that criterion and its effect on the analysis population are not described.
Finally, the registry record does not report a sample-size justification, handling of missing data, multiplicity control, or a statistical analysis plan. The adverse-event entries are limited to the reported categories and groups, and the death fields have no reported counts. These gaps do not demonstrate that a particular design or analysis choice was inappropriate; they limit what can be concluded from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Determination of Cell Population in Solution-Induced Corneal Staining (SICS) and Symptomatic Versus Asymptomatic Lens Wearers — NCT01629706.
- Registry record last updated 2015-03-03; status last verified 2015-01.
- Results first posted 2015-02-13.
- 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
NCT01629706 is a completed CIBA VISION study with an enrollment of 92. It is listed as randomized and triple-masked, with the model recorded as single group. The study began in 2012-09 and reached primary completion in 2014-01.
Phase 1 examined viable epithelial cell counts after lens wear under different lens-care conditions, with right and left eyes analyzed separately and assessments after two hours and four hours of wear. Phase 2 involved habitual bilateral lens wear for four weeks and aimed to examine cell appearance in symptomatic and asymptomatic wearers. The primary endpoint procedure is described, but its numerical results and analysis are not reported in the registry record.
The registry records zero participants affected by serious and other adverse events in the PureVision and Habitual groups. Death counts are not reported in the registry record. Details of the statistical analysis plan, missing-data handling, multiplicity procedures, and sample-size justification are also not reported.