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 A Comparison of Silicone Hydrogel Contact Lenses: AIR OPTIX® COLORS Versus AIR OPTIX® AQUA (NCT01635920), a randomized na study. The primary outcome is Percentage of Subjects With Same Fit in Both Eyes.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01635920 |
| Phase | NA |
| Condition | Myopia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 258 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Alcon Research |
| Results posted | Yes |
2. Clinical Question
Population
Participants with myopia who were enrolled and dispensed study lenses. The registry record describes the primary-outcome population as participants with at least one study visit after dispensing, but does not report further demographic details in the information available for this analysis.
Intervention
AIR OPTIX® COLORS, a colored Lotrafilcon B contact lens, worn bilaterally in daily-wear modality for 4 weeks, for a minimum of 5 days per week and 8 hours per day.
Comparator
AIR OPTIX® AQUA, a non-colored Lotrafilcon B contact lens, worn bilaterally under the same stated schedule: daily wear for 4 weeks, for a minimum of 5 days per week and 8 hours per day.
Primary question
What percentage of participants had the defined acceptable or optimal lens fit in both eyes with the study lens, with each eye’s fit also within one grade of the fit recorded for that same eye with the participant’s habitual lens at baseline? The registry record does not report the outcome values needed to compare the groups.
The study’s stated purpose was to compare the overall fit of the two lenses. Fit was assessed by an investigator using a biomicroscope, also called a slit lamp. The primary endpoint is expressed as a percentage of participants rather than as a mean fit score. The secondary outcome listed in the registry record is subjective rating of overall comfort, but its numerical results are not reported in the registry record.
3. Trial Design
The registry record describes a randomized, parallel-group study with no masking. Participants were assigned to AIR OPTIX® COLORS or AIR OPTIX® AQUA. Because masking was listed as none, the record does not describe the study as masked; it does not give further details about how assignment was generated or concealed. Those procedures are not reported in the registry record.
Both study lenses were Lotrafilcon B devices intended for bilateral daily wear. The arm descriptions specify a four-week wear period, a minimum of five days per week, and a minimum of eight hours per day. The colored lens was compared with the non-colored lens. The record does not state that participants crossed over between lenses; it identifies a parallel model, in which the groups remain separate rather than receiving treatments in sequence.
The condition listed is myopia, and the planned enrollment recorded is 258. The study is marked completed. Its recorded start was 2012-06 and primary completion was 2012-08. These dates and completion status describe the registry entry, not the timing or completeness of every participant’s follow-up.
The primary outcome was assessed up to Day 28. The record lists two outcome measures and identifies subjective overall comfort as a secondary outcome. It reports zero analyses, and numerical primary-outcome results are not available in the registry record. The statistical analysis plan, any planned interim analyses, the method used to randomize participants, and the rationale for the planned enrollment are not reported in the registry record. The trial is listed as phase NA, which does not provide a phase classification.
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 258 participants enrolled, 7 participants did not receive study lenses. This reporting group includes all enrolled and randomized participants who received study lenses (251).
Overall Study
| Stage | AIR OPTIX® COLORS | AIR OPTIX® AQUA |
|---|---|---|
| STARTED | 125 | 126 |
| COMPLETED | 122 | 125 |
| NOT COMPLETED | 3 | 1 |
Reasons for not completing this period:
| Reason | AIR OPTIX® COLORS | AIR OPTIX® AQUA |
|---|---|---|
| Adverse Event | 1 | 0 |
| Lost to Follow-up | 0 | 1 |
| Subject decision | 2 | 0 |
Analysis population for the primary outcome, as defined in the registry: ITT: All enrolled and dispensed participants who had at least one study visit after being dispensed with study lenses (N=125,126). No imputation was used for the missing values. Here, "n" is the number of participants with non-missing values at the specific time point for each arm group, respectively.
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: The analysis population includes all enrolled and randomized participants who received study lenses (251).
| Characteristic | Unit | AIR OPTIX® COLORS | AIR OPTIX® AQUA | Total |
|---|---|---|---|---|
| Participants analysed | 125 | 126 | 251 | |
| Age, Customized: 16-17 years | participants | 10 | 5 | 15 |
| Age, Customized: 18-64 years | participants | 115 | 119 | 234 |
| Age, Customized: ≥ 65 years | participants | 0 | 2 | 2 |
| Sex: Female, Male: Female | Participants | 92 | 91 | 183 |
| Sex: Female, Male: Male | Participants | 33 | 35 | 68 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Subjects With Same Fit in Both Eyes, measured over Up to Day 28.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants with the defined same fit in both eyes, assessed up to Day 28. An investigator evaluated the fit of each lens in each eye using a biomicroscope, or slit lamp. The fit scale ranges from unacceptably loose through optimal to unacceptably tight. The endpoint’s definition of “same fit” is not simply an identical numerical grade: each eye must have an acceptable or optimal overall fit with the study lens, and that eye’s study-lens fit must also be within one grade of the fit observed in the same eye with the habitual lens at baseline.
Expressing the endpoint as a participant percentage makes the outcome a binary classification at the participant level: a participant either meets the stated condition in both eyes or does not. This combines information from each eye and relates the study-lens fit to the individual’s habitual-lens fit at baseline. It is therefore different from reporting an average fit grade or a separate percentage for each eye.
As a general statistical point, a binary endpoint can be easy to interpret as a proportion meeting a defined criterion, but it does not show how far participants who fail the criterion were from meeting it. The registry record does not report the arm-specific percentages or counts for this primary endpoint. The observed comparison, and its statistical precision, therefore cannot be described from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the clinical question and the intended primary outcome, but does not provide numerical primary-outcome results. It is therefore not possible to state which group had a higher percentage of participants meeting the fit definition, how large any observed difference was, or how uncertain that comparison was. No effect estimate, confidence interval, or test result for the primary outcome is reported in the registry record.
The planned enrollment is 258. The adverse-event entries list 125 participants at risk in the AIR OPTIX® COLORS group and 126 in the AIR OPTIX® AQUA group. Those safety counts do not supply the missing primary-outcome results. Nor should enrollment or the safety denominators be treated as the number of participants with an observed primary endpoint: the record’s outcome description defines an analysis population based on post-dispensing visits and says that the number with non-missing values could vary by time point and arm.
The primary outcome concerns whether the fit in both eyes meets a prespecified definition relative to habitual-lens fit at baseline. It does not directly report comfort, visual performance, or other outcomes. Subjective rating of overall comfort is listed as a secondary outcome, but its numerical results are not reported in the registry record. The endpoint’s scope should not be expanded beyond lens fit as defined in the record.
As a general statistical point, a group comparison needs both an effect estimate and information about its uncertainty to support a careful interpretation. A confidence interval describes a range of values compatible with the data and analysis assumptions; without a reported estimate and interval, readers cannot judge precision. A p-value alone, even if it were reported, would not describe the size or practical meaning of an effect. Neither a p-value nor an interval for the primary outcome is reported in the registry record.
The registry record labels the study randomized, which is relevant to the intended comparison, but does not provide the allocation procedure or an analysis plan. The missing numerical results prevent assessment of the observed comparison regardless of the design label. No conclusion about similarity, superiority, or difference in fit can be drawn from the information reported for the primary endpoint.
9. Statistical Methods Explained
The reported primary outcome is binary at the participant level. A participant meets the endpoint only when the specified fit condition is met in both eyes. The outcome is summarized as a percentage of participants. As a general statistical explanation, percentages describe how common a defined outcome is within a group; comparing percentages between groups describes a difference in the frequency of that outcome. The registry record does not report the group percentages or the underlying endpoint counts, so no such comparison can be interpreted.
The definition uses each participant’s habitual-lens fit at baseline as a reference. The investigator graded lens fit on a five-point scale, from unacceptably loose to unacceptably tight, with optimal fit at the center. A qualifying study-lens fit had to be acceptable or optimal and within one grade of the same eye’s habitual-lens fit at baseline. This rule defines the classification; it does not mean that the study lens had to receive exactly the same grade as the habitual lens. The record does not report how investigators were trained or whether fit grading was checked for consistency.
As a general statistical point, confidence intervals express uncertainty around an estimated quantity under the analysis assumptions. For a binary outcome, an interval around a group percentage or a between-group contrast would help show how precisely the observed data estimate the outcome. The registry record gives neither an interval nor a primary-outcome estimate, so precision cannot be evaluated. A statistical test would address compatibility with a specified null hypothesis, but no primary-outcome test result is reported. A test result, by itself, would not convey the size of the difference or its practical importance.
The study is described as randomized and parallel-group. In general, random allocation is intended to make treatment groups comparable in expectation, while a parallel design keeps each participant in an assigned group for the comparison. The record does not report the randomization sequence method, concealment procedures, or whether any balancing factors were used. Masking is listed as none. The record does not say whether assessors were masked separately, so no further inference about assessor masking is warranted.
The registry record describes an intention-to-treat population as all enrolled and dispensed participants with at least one study visit after dispensing. It says no imputation was used for missing values, and that the number with non-missing values could differ by time point and arm. In general, an analysis without imputation uses observed outcome values rather than filling in missing ones with modeled or substituted values. This can make the analyzed set smaller than the enrolled set, and interpretation may depend on why values are missing. The record does not explain reasons for missingness or report the primary endpoint’s non-missing counts by group.
The registry record lists two outcome measures and zero analyses. It does not report the statistical model or test used for the primary comparison, any covariate adjustment, or a prespecified hierarchy among outcomes. These details are not reported in the registry record. It is not possible to infer the analysis from the endpoint format or from the fact that the study was randomized.
As a general concept, over-dispersion matters for count outcomes when variability exceeds what a chosen count model assumes; analysts may then need a model or standard errors that account for the extra variability. That issue is not described as applicable to this binary percentage endpoint, and the registry record does not report a model for which over-dispersion can be assessed.
The record’s sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such planning illustrations are not observed power and do not establish that the original study was designed using those assumptions. The registry record does not report the trial’s own sample-size justification, the effect size used in its original planning, or any interim analysis plan. Without outcome results, the illustration cannot be used to determine what the trial found.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists a primary outcome, “Percentage of Subjects With Same Fit in Both Eyes,” and a secondary outcome, subjective rating of overall comfort. It also records two outcome measures and zero analyses. Numerical results for the primary and secondary outcomes are not reported in the registry record. The record does not describe a hierarchy for testing outcomes, a multiplicity adjustment, or which outcomes were included in any confirmatory analysis. These details are not reported in the registry record; no correction or lack of correction should be assumed.
The stated analysis population includes enrolled and dispensed participants with at least one study visit after dispensing. The record says that no imputation was used for missing values. It also says that the number with non-missing values could vary by time point and arm. This means the record’s population description does not establish that every enrolled participant contributed a measured value to every outcome or time point. Group-specific counts of missing primary-outcome values and reasons for missingness are not reported in the registry record.
As a general statistical point, missing outcome values can affect interpretation if the participants with observed data differ systematically from those without observed data. Not using imputation avoids inserting modeled values, but does not by itself show that missingness has no effect on the comparison. Assessing that issue ordinarily requires information about the extent and pattern of missingness and the assumptions behind the analysis. Those details are not reported in the registry record.
The primary endpoint is assessed up to Day 28, and the record mentions multiple time points in describing non-missing values. It does not identify which specific time point was used for a single primary comparison, if any. The analysis population for each reported outcome and the handling of any repeated measurements are not reported in the registry record.
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 |
|---|---|---|---|
| AIR OPTIX® COLORS | 0 | 125 | 0.0% |
| AIR OPTIX® AQUA | 0 | 126 | 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 |
|---|---|
| AIR OPTIX® COLORS | 0 of 125 |
| AIR OPTIX® AQUA | 0 of 126 |
The adverse-event entries report zero serious adverse events in AIR OPTIX® COLORS among 125 participants at risk and zero serious adverse events in AIR OPTIX® AQUA among 126 participants at risk. The entries also report zero other adverse events in each group, using those same at-risk counts. These are the posted event counts for the registry record; they do not provide a detailed account of event collection or follow-up.
Deaths are listed as null for both groups. A null entry is not a reported zero, so the number of deaths is not reported in the registry record. The serious-event terms list is empty. The record does not provide event narratives, severity definitions, or additional details about how adverse events were monitored.
As a general statistical point, a count of zero observed events does not establish that an event is impossible or that no events occurred outside the recorded observation. The precision of safety estimates also depends on the number of participants observed and the completeness and duration of follow-up. The registry record gives the at-risk counts but does not provide further safety follow-up details. These figures should be read as the event counts recorded, not as proof of an absence of risk.
12. What the Result Does, and Does Not, Mean
The registry record establishes that the study was a randomized, parallel comparison of AIR OPTIX® COLORS and AIR OPTIX® AQUA, with investigator-assessed fit as the primary outcome. It defines the endpoint in relation to acceptable or optimal fit in both eyes and each eye’s habitual-lens fit at baseline. However, the registry record does not report the primary outcome values. It therefore does not establish whether the groups differed in the percentage meeting that definition, or how precisely a difference was estimated.
The record also identifies subjective overall comfort as a secondary outcome, but does not report its numerical results. It cannot support a conclusion about comfort from the information available. Likewise, the safety entries record zero serious and zero other adverse events in each group, but deaths are not reported and the record does not provide further details about safety follow-up. These entries should not be treated as a complete account of all possible safety outcomes.
As a general statistical point, a randomized design can support a between-group comparison when the assignment and analysis are properly conducted, but the design label does not substitute for outcome results. Interpretation depends on the observed estimates, their uncertainty, missing-data handling, and the analysis plan. Several of these details are not reported in the registry record.
The endpoint is limited to the stated definition of lens fit; it does not by itself answer broader questions about comfort or other aspects of contact-lens use. The record does not provide information to establish whether the findings generalize beyond the study participants or the specified wear schedule. In the absence of numerical endpoint results, the central result of the comparison remains undetermined from the registry record.
13. Why This Trial Matters Statistically
This trial is statistically notable for the way its primary endpoint turns eye-level fit assessments into a participant-level binary outcome. Investigators graded each eye, but the primary measure is the percentage of participants meeting the fit rule in both eyes. That distinction matters: a participant-level endpoint is not equivalent to an average grade or to an eye-level percentage. The definition also anchors each study-eye assessment to that same eye’s habitual-lens fit at baseline.
The trial is recorded as randomized and parallel, but it is unmasked. Those design features frame how the comparison was intended to be conducted. The registry record does not report the randomization procedure, the analysis plan, or whether fit assessors were masked. Readers therefore cannot evaluate those procedural details from the record.
The statistical interpretation is constrained most directly by the absence of numerical primary-outcome results. Without group estimates and measures of uncertainty, it is impossible to assess the direction, magnitude, or precision of the fit comparison. The record also describes an analysis population that excludes participants without a post-dispensing study visit and says no imputation was used, while not reporting the endpoint-specific non-missing counts or reasons for missingness.
As a general statistical lesson, a well-defined outcome and a randomized design do not alone convey the result of a trial. Numerical estimates, uncertainty, and transparent reporting of the analysis population are needed to understand what the observed data show. In this record, the endpoint definition is clear enough to describe the question, but the reported information does not answer it.
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 central limitation for interpreting this trial is that numerical results for the primary endpoint are not reported in the registry record. The primary outcome is identified and defined, but there are no arm-specific percentages, counts, effect estimates, confidence intervals, or p-values available for interpretation. The secondary outcome of subjective overall comfort is listed without numerical results as well.
The record describes an intention-to-treat population based on having at least one study visit after dispensing. It states that no imputation was used and that non-missing counts could vary by time point and arm, but does not give the primary outcome’s complete counts by group or explain why values were missing. The record’s population notation is “N=125,126”; further clarification of that notation is not reported in the registry record.
Although the study is marked randomized, the method of generating and concealing assignments is not reported in the registry record. Masking is listed as none, and the record does not separately clarify masking of the fit assessors. The analysis method, covariate adjustment, choice of primary analysis time point, multiplicity handling, and trial-specific sample-size justification are also not reported in the registry record.
The available information does not describe participant characteristics beyond the listed condition of myopia, nor does it provide detailed adherence or follow-up information. The arm descriptions state the intended lens-wear schedule, but do not establish how closely participants followed it. The registry record’s safety entries do not include further event details, and deaths are not reported. These limitations restrict assessment of the comparison, its precision, and the completeness of outcome and safety reporting.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Comparison of Silicone Hydrogel Contact Lenses: AIR OPTIX® COLORS Versus AIR OPTIX® AQUA — NCT01635920.
- Registry record last updated 2014-03-28; status last verified 2014-02.
- Results first posted 2014-03-28.
- 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
The registry record describes NCT01635920, a completed, randomized, unmasked, parallel-group comparison of AIR OPTIX® COLORS and AIR OPTIX® AQUA contact lenses in participants with myopia. Planned enrollment was 258. Both lenses were Lotrafilcon B devices intended for bilateral daily wear over 4 weeks, for a minimum of 5 days per week and 8 hours per day.
The primary outcome was the percentage of participants with the defined acceptable or optimal fit in both eyes, assessed up to Day 28 against habitual-lens fit at baseline. Subjective rating of overall comfort was listed as a secondary outcome. The registry record describes an analysis population requiring at least one post-dispensing study visit and states that no imputation was used for missing values.
Numerical results for the primary and secondary outcomes are not reported in the registry record. The adverse-event entries report zero serious and zero other adverse events in each group; deaths are not reported.