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 Study of the Presence and Extent of Corneal Disturbance Associated With B+L Biotrue MPS Used With B+L PureVision Lenses (NCT01268306), a na phase 4 study. The primary outcome is Number of Participants Wiith Corneal Staining.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01268306 |
| Phase | Phase 4 |
| Condition | Keratitis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 8 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Epstein, Arthur B., OD, FAAO |
| Results posted | Yes |
2. Clinical Question
Population
The study enrolled 8 participants. The arm description identifies them as successful contact lens wearers who switched to B+L BioTrue multi-purpose solution while wearing B+L PureVision lenses. The primary endpoint description refers to subjects returning for examination after the challenge within the allotted time; the number meeting that description is not reported in the registry record.
Intervention
Participants used B+L BioTrue multi-purpose solution with B+L PureVision contact lenses. The registry record characterizes the study as an evaluation of biocompatibility and corneal staining associated with this product combination.
Comparator
There was no separate comparator arm. The registry record classifies the study as single-group and does not report randomized allocation. The findings therefore describe this group rather than a like-for-like comparison between lens-care regimens.
Primary question
The study asked how many participants had corneal staining detected by sodium fluorescein and slit-lamp biomicroscopy after contact lens insertion. The specified assessment window was 2-4 hours after insertion. The number of participants meeting the endpoint is not reported in the registry record.
The registry background places the question in the context of corneal epithelial disruption associated with contact lens wear. It notes that earlier research had described higher levels of staining with some combinations of lenses and care products, and identifies PureVision lenses as having been associated with high observed staining in previous research. The study examined staining with BioTrue used alongside those lenses; it does not report a comparison against another solution or lens combination.
3. Trial Design
This was a prospective, open-label, single-site Phase 4 study, with a single group and no randomized allocation. The registry record lists 8 participants as the enrollment. Its arm description says successful contact lens wearers switched to B+L BioTrue multi-purpose solution while wearing B+L PureVision lenses. The record marks the study as completed and gives a start date of 2010-10 and primary completion date of 2010-12.
A single-group design can describe what was observed among participants using a particular product combination. Because no separate comparator group is reported, it cannot directly estimate how staining would differ under another regimen. The study is also listed as open-label, so masking is recorded as none. The record does not describe blinded outcome assessment or provide further details about how the examiners assessed staining beyond the endpoint description.
The primary outcome was a participant count for corneal staining observed with sodium fluorescein and slit-lamp biomicroscopy. The assessment timeframe was 2-4 hours after lens insertion. The registry record describes clinically significant staining as sufficiently diffuse and deep to pose a potential risk of infection, based on the examiner’s assessment. The outcome result itself is not reported in the registry record, and the number of participants examined for that endpoint is not stated.
The record identifies Keratitis as the condition and lists B+L BioTrue MPS and B+L PureVision as the intervention. It does not report a protocol, detailed eligibility criteria, a sample-size justification, interim analyses, or a statistical analysis plan. Those design details should not be inferred from the study’s enrollment or its outcome definition.
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: Patients with spherical contact lens corrections who achieved acceptable acuity with test lenses were offered study participation.
Overall Study
| Stage | Bausch & Lomb (B+L) Biotrue MPS With B+L PureVision Lenses |
|---|---|
| STARTED | 8 |
| COMPLETED | 7 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Bausch & Lomb (B+L) Biotrue MPS With B+L PureVision Lenses |
|---|---|
| Lost to Follow-up | 1 |
Analysis population for the primary outcome, as defined in the registry: Subjects who returned for examination post-challenge in the allotted time and who had observable corneal staining on slit lamp examination
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 | Bausch & Lomb (B+L) Biotrue MPS With B+L PureVision Lenses |
|---|---|---|
| Participants analysed | 8 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 8 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 5 |
| Sex: Female, Male: Male | Participants | 3 |
| Region of Enrollment: United States | participants | 8 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Wiith Corneal Staining, measured over 2-4 hours after contact lens insertion.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants with corneal staining. The registry describes staining as disturbance of the corneal epithelium visualized after applying sodium fluorescein as a disclosing agent and examining the eye by slit-lamp biomicroscopy. The stated assessment window is 2-4 hours after contact lens insertion. The registry’s description of clinically significant staining refers to staining that an examiner judges sufficiently diffuse and deep to pose a potential risk of infection.
This endpoint is used to record whether staining was observed in participants at the specified examination. As a participant count, it is a binary-outcome summary: each assessed participant either meets the endpoint definition or does not. General statistical context: a count is easier to interpret when its denominator is also clear, because the count alone does not indicate how common the finding was among those assessed. The registry record does not report the endpoint count or the number assessed, so the observed frequency cannot be described from that record.
The measure captures an examination finding at a defined time, not a comparison between products and not, by itself, a measure of longer-term clinical outcomes. The registry identifies the assessment method and a description of clinically significant staining, but does not report separate counts by staining severity or further endpoint results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the question and endpoint but does not report the primary endpoint result. It therefore does not establish how many participants had corneal staining after using BioTrue with PureVision lenses. Although enrollment is listed as 8, that figure is not a substitute for the number examined at the endpoint. The outcome population is described as subjects who returned for examination after the challenge within the allotted time and who had observable staining; the number in that population is not reported.
The endpoint is a count of participants with staining, assessed using sodium fluorescein and slit-lamp biomicroscopy during the 2-4 hours after insertion. The registry also defines clinically significant staining in terms of the examiner’s assessment of how diffuse and deep it is. No primary endpoint count, estimate of uncertainty, or analysis result is reported. Consequently, the posted record does not support a quantitative description of the observed staining outcome or its precision.
The design is single-group and open-label, with no randomized allocation or separate comparator arm. General statistical context: a single-group observation can describe the findings in the people assessed, but it does not isolate what would have happened under a different product combination. Without a like-for-like comparison, differences attributed to a regimen cannot be estimated from this study design alone. The record’s background discusses prior observations about staining and lens-care combinations, but those statements are context, not results from a concurrent comparison in this study.
The record lists 8 participants enrolled. It also reports zero serious adverse events and zero other adverse events for the intervention group, with 8 at risk in each category. Those safety counts are distinct from the corneal-staining endpoint. The registry does not state that the primary staining result was zero, and the adverse-event figures should not be used to infer it.
No analysis records are listed. The registry record does not report the statistical plan, confidence intervals, hypothesis tests, missing-data handling, or analysis populations. A planning illustration is described as based on a fraction of the observed effect and specified assumptions, but the observed endpoint effect and resulting planning values are not reported in the registry record. Such planning illustrations, where available, concern hypothetical future study design; they are not observed power and cannot fill the gap in the primary outcome result.
9. Statistical Methods Explained
The registry record describes a single-group, prospective, open-label study. No randomized allocation or comparator arm is reported. These design features determine what can be learned from an analysis: the study can characterize observations in the participants assessed, but it cannot use a concurrent control group to estimate a between-regimen contrast. The record does not report a statistical analysis plan, so the methods actually used for the primary endpoint cannot be specified beyond the outcome definition and assessment method.
What kind of outcome is recorded?
The primary outcome is the number of participants with corneal staining. This is a binary outcome at the participant level: staining is either observed according to the endpoint assessment or it is not. General statistical context: binary outcomes are often described with a count and a proportion, with the denominator identifying how many participants were assessed. A proportion would make the count interpretable relative to the assessed group, but neither the primary count nor the denominator is reported in the registry record. No proportion should therefore be inferred from enrollment alone.
The endpoint uses sodium fluorescein to disclose corneal epithelial disturbance, followed by slit-lamp biomicroscopy. The registry specifies assessment 2-4 hours after insertion and describes clinically significant staining by its extent and depth as judged by the examiner. It does not report separate outcome categories, a grading scale, assessor agreement, or a detailed statistical rule for translating observations into the participant count.
What does the design allow?
With a single group, a primary endpoint count would describe the participants who were assessed under the study regimen. It would not, on its own, show whether the count was higher or lower than it would have been with another lens-care product or lens. General statistical context: causal comparisons are strengthened by a suitable comparison group and methods that address differences between groups. Neither a comparison arm nor a randomized allocation is recorded. The study is open-label, and masking is listed as none; further information about masking of endpoint assessors is not reported in the registry record.
Enrollment is listed as 8, while the endpoint population description refers to participants who returned for examination within the allotted time and had observable staining. The record does not state how many returned, how many were examined, or how many entered the analysis. Those quantities are important for interpreting a count, especially if not every enrolled participant contributed an endpoint observation. The record does not describe missing-data procedures or reasons for any non-return.
What uncertainty can be assessed?
General statistical context: a confidence interval expresses the range of values compatible with data under a specified statistical method and assumptions. Its width reflects uncertainty as well as the amount and pattern of information available. A confidence interval would not correct limitations such as the lack of a comparator, and it cannot be interpreted without knowing the endpoint estimate and analyzed population. The registry record reports no confidence interval or primary endpoint estimate.
The record lists no analysis records. It does not report a hypothesis test, significance threshold for an endpoint analysis, adjustment method, or model. It is therefore not possible to describe whether a formal test was conducted or how uncertainty was quantified. The absence of an analysis record is not evidence that a particular method was or was not used outside the registry entry.
How should planning illustrations be read?
The registry describes a planning illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. It specifies that non-time-to-event planning values are participants per arm and time-to-event values are total events. These are assumptions for illustrating possible future sample sizes, not the design or observed result of this single-group study. The record does not report the observed primary effect or numeric planning outputs. General statistical context: sample-size calculations depend on the effect chosen for planning and other assumptions; changing those assumptions changes the resulting target. A planning calculation is not observed power, and it cannot establish what the study found.
Because no endpoint result, analysis population, or statistical analysis is reported, numerical precision cannot be evaluated. The most defensible statistical reading is limited to the design, endpoint definition, assessment timeframe, and enrollment stated in the registry record, alongside the explicit recognition that the primary result is not reported.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one outcome measure and no analysis records. It does not report whether multiple hypotheses, outcome definitions, or subgroup analyses were considered in the investigators’ analysis plan. No multiplicity adjustment or testing hierarchy is described. With no primary endpoint result or analysis details, it is not possible to assess how any multiplicity concerns were handled.
The record gives enrollment as 8, but does not state how many participants returned for the post-challenge examination, how many were assessed, or how many were included in an analysis. The primary endpoint population description is restricted to subjects who returned within the allotted time and had observable staining. The number meeting that description is not reported in the registry record. Reasons for non-return, incomplete examinations, or missing endpoint observations are also not reported.
The record does not describe an intention-to-treat population, a per-protocol population, or another analysis population. It does not state how missing or unevaluable observations were handled. General statistical context: when some enrolled participants lack an outcome assessment, the analysis denominator and the reasons for missingness matter because conclusions may depend on who was observed. Without those details, the completeness and representativeness of the endpoint data cannot be evaluated.
The serious and other adverse-event denominators are recorded separately as 8 at risk for each category. Those safety denominators do not establish the denominator used for the primary staining analysis.
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 |
|---|---|---|---|
| Bausch & Lomb (B+L) Biotrue MPS With B+L PureVision Lenses | 0 | 8 | 0.0% |
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 |
|---|---|
| Bausch & Lomb (B+L) Biotrue MPS With B+L PureVision Lenses | 0 of 8 |
The registry reports 0 serious adverse events among 8 participants at risk in the intervention group, and 0 other adverse events among 8 participants at risk. No serious adverse-event terms are listed. These are the posted safety counts for the categories recorded; they should be read separately from the primary corneal-staining outcome, whose result is not reported in the registry record.
General statistical context: a zero count in a small group does not establish that an event is impossible or that the true event frequency is zero. The observed count describes only what was recorded for the participants at risk during the study’s safety reporting. The registry entry does not provide additional detail about safety-event definitions, event collection procedures, or the duration of safety follow-up. The endpoint timeframe of 2-4 hours after lens insertion is specified for staining and should not be treated as the safety follow-up period.
The figures do not support a comparison of safety between products because the registry describes only one group. They also do not establish the primary staining count or its clinical significance.
12. What the Result Does, and Does Not, Mean
The study is described as a prospective evaluation of corneal staining with B+L BioTrue multi-purpose solution used alongside B+L PureVision contact lenses. It enrolled 8 participants and specified an examination using sodium fluorescein and slit-lamp biomicroscopy during the 2-4 hours after lens insertion. The primary outcome was the number of participants with staining, with clinically significant staining described by the examiner’s assessment of its extent and depth.
The registry record does not report the primary staining count, the endpoint denominator, or an analysis estimate. It therefore does not show how many participants had staining or how precisely that outcome was estimated. The reported zero counts for serious and other adverse events are safety results, not results for corneal staining.
The design has one group and no randomized comparator. General statistical context: an observation in one group cannot establish what would have occurred under a different regimen. This study’s registry entry therefore does not provide a direct estimate of a difference between BioTrue and another lens-care product, or between PureVision and another lens. The background discussion of previous research is not a concurrent comparison in this study.
The findings that can be described are limited to the stated study design, intervention, enrollment, endpoint definition, timeframe, and posted adverse-event counts. The record does not report the protocol, sample-size justification, statistical analysis plan, missing-data handling, or primary outcome result. It is not possible to draw a numerical conclusion about the frequency of staining from the registry record, or to use the safety counts as a substitute for that missing endpoint result.
13. Why This Trial Matters Statistically
This study illustrates why outcome definitions and denominators are central to interpreting clinical results. The registry defines a specific examination finding, method, and assessment window, and describes how examiners judged clinically significant staining. Yet the primary endpoint count and the number assessed are not reported. Without both, the endpoint’s observed frequency and precision cannot be evaluated.
The single-group design also makes the distinction between description and comparison especially important. The study can be understood as evaluating observations under one product combination, but the registry does not report a concurrent control arm or randomized allocation. General statistical context: an outcome count alone does not estimate a treatment contrast, because a contrast requires outcomes from a suitable comparison or another defensible source of counterfactual information.
The record separates a primary examination outcome from adverse-event reporting. It reports zero serious and zero other adverse events among 8 at risk in each category, but those counts do not answer how many participants had corneal staining. Keeping endpoint definitions and denominators separate prevents one kind of result from being mistaken for another.
Finally, the registry describes planning assumptions for hypothetical sample-size illustrations, while the primary observed effect and the analysis results are not reported. This distinction matters: design calculations address prospective planning under assumptions, whereas study results describe observations actually analyzed. A planning illustration cannot replace an outcome estimate or indicate observed power. The record is therefore useful for identifying the clinical question and design, but its missing primary result sharply limits statistical interpretation.
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 results is that the registry record does not report the primary corneal-staining count or the number of participants assessed for that endpoint. Enrollment is listed as 8, but the record does not establish that every enrolled participant returned or contributed an endpoint observation. The stated endpoint population is limited to subjects who returned within the allotted time and had observable staining, and its size is not reported.
The study has a single group, no randomized allocation, and no separate comparator. As a result, the registry entry does not support a direct comparison with another lens-care product or lens regimen. Its open-label status and lack of masking are recorded, while further information about blinded outcome assessment is not reported. The endpoint relies on examination and an examiner’s assessment of the extent and depth of staining; additional information about grading procedures or assessor agreement is not reported.
The registry record does not report a protocol, sample-size justification, statistical analysis plan, interim analyses, analysis population, missing-data method, or primary endpoint analysis. It also does not report a confidence interval or other measure of precision for the staining outcome. These omissions prevent assessment of the planned analysis, data completeness, and uncertainty around the primary result.
The adverse-event counts are recorded, but safety follow-up details and event-collection methods are not reported. Those counts do not resolve the missing primary endpoint result. The registry background gives context about prior observations, but it does not supply a concurrent control for this study.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study of the Presence and Extent of Corneal Disturbance Associated With B+L Biotrue MPS Used With B+L PureVision Lenses — NCT01268306.
- Registry record last updated 2016-08-22; status last verified 2016-08.
- Results first posted 2016-08-22.
- 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 a completed, prospective, open-label, single-site Phase 4, single-group study with enrollment of 8. Participants used B+L BioTrue multi-purpose solution with B+L PureVision contact lenses. The primary outcome was the number of participants with corneal staining observed by sodium fluorescein and slit-lamp biomicroscopy 2-4 hours after lens insertion.
The primary staining result and the number assessed are not reported in the registry record. No randomized comparison, analysis records, or statistical analysis plan are reported. The record lists 0 serious adverse events and 0 other adverse events, with 8 at risk in each category. These safety figures are distinct from the unreported primary endpoint result.