Evaluation of Investigational (Frequent Replacement) FRP Lens for Daily Wear: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Investigational (Frequent Replacement) FRP Lens for Daily Wear (NCT02362724), a randomized na study. The primary outcome is Slit Lamp Findings for Epithelial Edema.

2. Clinical Question

The study purpose is described as comparing an investigational contact lens with a marketed contact lens. The posted information identifies Sapphire and Pearl as the study devices, but does not give a numerical estimate of their difference on the primary endpoint. It therefore cannot establish from the registry record whether one arm had more or fewer eyes with epithelial edema, or whether any observed difference was compatible with chance variation.

The main question is also narrower than a broad assessment of lens performance: the listed primary measure is a slit-lamp finding at a specified assessment time, rather than a summary of all outcomes over the study. The record lists 16 outcome measures, but does not provide an analysis that combines them into a single overall comparison. The stated summary adds that the results were not used for design validation of the investigational contact lens. That qualification is relevant to how the study's purpose should be understood, but it does not supply a missing clinical or statistical result.

3. Trial Design

The registry describes a randomized, double-masked, parallel-group study. Participants were assigned to Sapphire, described as the experimental lens, or Pearl, described as the active comparator. Randomization is intended to make treatment groups comparable on average with respect to measured and unmeasured characteristics, although it cannot guarantee balance in a particular trial. The record does not report the randomization procedure or how the masking was implemented, including which people were masked.

The listed condition is ametropia. Enrollment is recorded as 89. The registry marks the study as completed, with a start in 2015-02 and primary completion in 2015-06. The title describes silicone hydrogel daily-wear contact lenses used for frequent replacement for up to One (1) Month. The brief summary identifies the comparison as an investigational contact lens versus a marketed contact lens. The registry does not report further details of the visit schedule, lens replacement instructions, or adherence assessments.

The primary outcome is “Slit Lamp Findings for Epithelial Edema,” with the unit recorded as eyes and the parameter recorded as number. Its assessment time is Baseline (After lens dispensing). This wording places the specified assessment after dispensing, even though it is labeled baseline; the registry does not clarify how that timing relates to any later assessments. The description gives an ordinal grading scale from 0 to 4.

The registry lists 16 outcome measures and 0 analyses. It does not report an outcome estimate, uncertainty interval, hypothesis test, or comparison for the primary endpoint. A sample-size justification, the target enrollment rationale, and any protocol-level analysis plan are not reported in the registry record. The listed enrollment and the group-specific safety counts should not be treated as substitutes for those missing design details. The registry also states that the study results were not used for design validation of the investigational lens.

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.

Overall Study

Reasons for not completing this period:

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.

6. Primary Endpoint

The registry lists the primary outcome as Slit Lamp Findings for Epithelial Edema, measured over Baseline (After lens dispensing).

The primary endpoint is the number of eyes with slit-lamp findings of epithelial edema, assessed at Baseline (After lens dispensing). The registry describes a 0-to-4 grade. Grade 0 is NONE, with no microcysts and normal transparency. Grade 1 is TRACE, with 1 to 20 microcysts and barely discernible local epithelial haziness. Grade 2 is MILD, with 21 to 50 microcysts and faint but definite localized or generalized haziness. Grade 3 is MODERATE, with 51 to 100 microcysts and significant localized or generalized haziness. Grade 4 is SEVERE, with >100 microcysts, definite widespread epithelial cloudiness giving a dull glass appearance to the cornea, or numerous coalescing bullae.

Slit-lamp grading is a structured clinical observation: the scale distinguishes increasing levels of visible findings rather than recording a continuous measurement. Counting eyes by grade can describe how often findings at different levels occurred. It can also support a comparison between study arms if the results and analysis are reported. The registry's choice of eyes as the unit means an eye-level count is intended; the record does not explain how the analysis would account for two eyes belonging to one participant, if both contributed.

The endpoint is useful for documenting the specific corneal finding named in the outcome, but it does not by itself summarize every aspect of lens performance or participant experience. No grade counts, arm-specific primary outcome results, or analysis are reported in the registry record. Thus, the endpoint definition is available, but its observed distribution and comparative interpretation are not.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does randomization contribute?

Randomization assigns participants to study arms using a chance-based process. General statistical context: when allocation is implemented as planned, it reduces the risk that treatment assignment systematically depends on participant characteristics. This supports a fair comparison, but it does not ensure that every characteristic is balanced in the enrolled groups. Randomization also does not resolve problems caused by missing outcomes, deviations from assigned treatment, or an analysis that does not match the design.

The registry identifies this study as randomized, double-masked, and parallel. “Parallel” means the arms are separate groups rather than a sequence of treatments received by each participant. “Double-masked” indicates masking at more than one level, but the record does not identify who was masked or describe the procedures. Details of the allocation sequence and concealment are not reported in the registry record.

How should the endpoint scale be understood?

The primary outcome records the number of eyes with slit-lamp findings of epithelial edema, using grades from 0 to 4. General statistical context: the grades are ordered by severity, but an ordinal scale does not guarantee that each step represents the same change in the underlying condition. A count by category can show the distribution without imposing equal spacing. Other summaries may be possible, but their interpretation depends on the chosen method and its assumptions.

The unit is eyes, whereas treatment assignment is described for participants. General statistical context: when a person can contribute observations from both eyes, those observations may be correlated rather than statistically independent. An analysis that treats correlated observations as independent can understate uncertainty. The registry identifies eyes as the outcome unit but does not report whether both eyes contributed, how eye-level dependence was handled, or the model used for the endpoint.

What can a comparison estimate?

General statistical context: an unadjusted comparison contrasts the observed outcome summaries between arms without controlling for other variables. An adjusted comparison accounts for selected covariates through a statistical model. Either approach requires actual outcome data and a defined estimand: a precise statement of which outcomes, participants, and treatment conditions the comparison represents. The registry record does not report a primary endpoint estimate, a model, adjustment variables, or an estimand.

For a categorical endpoint, a comparison might use the full distribution across grades or a prespecified summary. Different choices answer different questions. For example, a distributional comparison asks whether the pattern across categories differs, while a comparison of a selected threshold focuses on findings meeting that threshold. These are general examples, not descriptions of analyses reported for this study. No choice of this kind is documented in the registry record.

How should uncertainty be read?

General statistical context: a confidence interval gives a range of values compatible with the observed data under a specified statistical procedure. Its width reflects precision, which depends on the data and analysis assumptions. A narrow interval indicates greater precision than a wide interval, but neither width nor statistical significance by itself determines clinical importance. Because the registry does not report an estimate or confidence interval for the primary outcome, the precision of any Sapphire–Pearl contrast cannot be assessed.

A hypothesis test, if used, would require a specified null hypothesis and test procedure. A p-value would then summarize the compatibility of the data with that null hypothesis under the model. It would not be the probability that the null hypothesis is true, nor would it show the size or importance of an effect. No primary endpoint p-value or inferential test is reported in the registry record.

What does the planning illustration represent?

The stated planning assumptions describe an illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. General statistical context: such calculations explore the sample size associated with chosen assumptions; they do not report what happened in the trial and are not observed power. The sample-size assumptions also state that non-time-to-event planning quantities are expressed as participants per arm.

Those assumptions do not replace the trial's own design rationale. A protocol-based sample-size justification and its inputs are not reported in the registry record. In addition, the record does not reduce the primary endpoint's several categories or time points to one comparison. No numerical planning result or observed primary effect is reported in the registry information used for this interpretation, so there is no basis for stating a target sample size, achieved power, or a numeric planning estimate.

Why can over-dispersion matter?

General statistical context: count data are sometimes analyzed using a model that assumes a particular relation between the mean and variability. Over-dispersion occurs when observed variability exceeds what that model expects. If ignored, uncertainty estimates can be too small and tests can appear more decisive than warranted. Whether over-dispersion is relevant depends on the specific outcome and model. The registry record does not identify a count-data model or report a dispersion assessment, so this is a general consideration rather than a study-specific finding.

More broadly, analysis choices should be prespecified and connected to the endpoint's measurement structure. The registry record does not report a statistical analysis plan, outcome model, handling of eye-level dependence, or inferential results. The described design supports identifying the intended comparison, but it does not reveal which statistical methods were actually used.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 16 outcome measures, while the primary outcome itself is described in terms of several grades and the record indicates that it has several categories or time points and was not reduced to one comparison. When a study assesses multiple outcomes, categories, time points, or contrasts, the chance of obtaining at least one apparently unusual result can increase if each is tested without regard to the others. General statistical context: multiplicity procedures can control or otherwise address this issue, but the appropriate approach depends on the questions and analysis plan.

A multiplicity strategy, including whether the primary outcome was prioritized over other measures or whether any adjustment was planned, is not reported in the registry record. The record also lists 0 analyses, so there are no posted hypothesis tests to interpret in light of multiplicity. It would be inappropriate to infer that testing was or was not adjusted.

Missing data can affect both the estimated outcome and its uncertainty, especially when the chance of missingness is related to treatment assignment or participant outcomes. General statistical context: analyses may use different assumptions about missing observations, and sensitivity analyses can examine how conclusions change under alternative assumptions. The registry record does not report missing endpoint counts, reasons for missingness, a missing-data method, or sensitivity analyses.

The analysis populations are also not described. The record does not say whether the primary analysis included all randomized participants, only participants who followed the assigned lens use, or another defined group. These distinctions matter because excluding participants after randomization can affect comparability between arms. The enrollment figure and the group-specific safety listings do not establish the primary endpoint analysis population.

These omissions do not show that the study lacked a plan or that data were missing; they mean those details are not reported in the registry record. Without a stated analysis population, missing-data accounting, and multiplicity approach, readers cannot assess those aspects of the primary comparison.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 2% reporting threshold.

Most frequent non-serious adverse event terms

The safety listing distinguishes serious adverse events from other adverse events and deaths. For Sapphire, 59 participants were listed at risk for serious events and 0 were affected; 59 were listed at risk for other adverse events and 7 were affected. For Pearl, 30 participants were listed at risk for serious events and 0 were affected; 30 were listed at risk for other adverse events and 2 were affected. Deaths are recorded as 0 in each arm. These are the registry's group-specific counts; no rates or comparative estimates are reported.

The serious-event counts describe what is listed in the record, not proof that no serious event could occur or that the arms have equivalent safety. The record does not list serious-event terms. For other adverse events, it does not provide the event types, severity, timing, relationship to lens use, or whether a participant could contribute more than one event. The count of participants affected should not be interpreted as a count of all event episodes.

General statistical context: safety comparisons need to consider the event definition, observation period, completeness of reporting, and uncertainty around the counts. The registry does not report a comparative safety analysis or uncertainty estimates. These figures are therefore descriptive and should not be treated as evidence of a statistical difference or equivalence between Sapphire and Pearl.

12. What the Result Does, and Does Not, Mean

The registry record documents a randomized, double-masked, parallel comparison of Sapphire and Pearl daily-wear contact lenses, with an epithelial-edema measure listed as the primary outcome. It provides the grade definitions and assessment time, Baseline (After lens dispensing). It also lists the study as completed and gives enrollment as 89. These details establish what comparison and measure were registered.

They do not establish the outcome of that comparison. The record does not report primary endpoint counts by grade or arm, an estimated difference, an uncertainty interval, or a test of the comparison. It is therefore not possible to determine from this record whether the observed epithelial-edema findings favored either lens, whether the arms appeared similar, or how precise a comparison would be. Absence of a posted result is not evidence that the treatments had identical outcomes.

Likewise, the safety counts do not establish comparative safety. The listing reports 0 serious adverse events in each arm and 0 deaths in each arm, along with other adverse events affecting 7 participants assigned to Sapphire and 2 assigned to Pearl. Without event details, a comparative analysis, and an account of uncertainty, those counts cannot show whether one lens has a higher or lower risk.

General statistical context: a nonsignificant test, if one were reported, would not by itself establish equivalence or noninferiority. Such conclusions require a defined margin and an appropriate analysis. The registry does not report an equivalence or noninferiority objective or analysis. No clinical recommendation follows from the information recorded.

The brief summary states that the study results were not used for design validation of the investigational contact lens. That statement limits the role attributed to these results in validation, but it does not substitute for outcome reporting. The defensible interpretation is that the registry describes the planned comparison and some safety counts, while leaving the primary comparative result and its precision unreported.

13. Why This Trial Matters Statistically

This study illustrates a distinction that is central to clinical statistics: a clearly defined endpoint is not the same as a reported result. The registry gives a detailed epithelial-edema grading scale and names the assessment time, so readers can identify what was intended to be measured. Yet without arm-specific grade counts or a comparison, they cannot judge the observed pattern or quantify uncertainty.

It also highlights the importance of matching the analysis to the measurement structure. The registered outcome is expressed as a number of eyes, while the treatment assignment is described at the participant level. General statistical context: analyses should account for dependence when multiple observations come from one participant. The record does not state how eye-level observations were handled, which makes the absence of a reported method especially relevant for interpreting the planned endpoint.

The record's description of a primary measure with multiple categories or time points also underscores why a statistical analysis plan matters. Decisions about summaries, contrasts, time points, missing observations, and multiplicity influence what a result means. Those decisions are not reported in the registry record, and no analyses are listed. It would be unjustified to select a preferred method retrospectively and present its interpretation as the trial's own analysis.

Finally, descriptive safety counts and a completed-study status cannot fill the gap in primary outcome reporting. The safety listing is useful for identifying the counts recorded, but it is not a comparative estimate. The study's stated non-use for design validation is another important context for understanding its role. Statistically, the key lesson is to distinguish what the registry documents about design and measurement from what it does not document about effects, precision, and analysis.

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 interpretation is that the registry record does not report numerical results for the primary endpoint. Although the outcome name, unit, grading scale, and assessment time are listed, there are no posted grade counts or arm-level comparison. This prevents estimation of the direction, size, or precision of a primary outcome contrast.

The record lists 16 outcome measures and 0 analyses. It does not specify how the multiple grades or time points were to be summarized, which contrast was intended, or how multiplicity was addressed. A statistical analysis plan, primary estimand, and inferential method are not reported in the registry record. The record also does not state whether observations from both eyes were included or how any within-participant dependence was handled.

Information about the analysis population and missing data is absent. The registry does not report how many participants contributed primary endpoint data, whether outcomes were missing, why any data might be missing, or how such observations were handled. Enrollment is recorded as 89, while the safety listing gives its own group-specific numbers at risk; the record does not explain the relationship between these figures and the primary endpoint analysis population.

Trial conduct details are limited in the registry information. The allocation method, masking procedures, adherence, discontinuations, and visit schedule beyond the listed primary assessment are not reported. Nor is a protocol-based sample-size justification reported. The study's stated results were not used for design validation of the investigational lens, which is relevant when considering the purpose and role of the study.

These limitations concern what can be learned from the registry record; they do not establish that the study did not collect the information. They restrict the interpretation of the posted material and preclude a statistical conclusion about the primary lens comparison.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Evaluation of Investigational (Frequent Replacement) FRP Lens for Daily Wear — NCT02362724.
• Registry record last updated 2020-10-14; status last verified 2015-12.
• Results first posted 2020-09-24.
• 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.

18. Record Summary

The registry identifies a completed, randomized, double-masked, parallel study of Sapphire and Pearl daily-wear contact lenses for frequent replacement. The listed condition is ametropia, and enrollment is recorded as 89. The study title describes use for up to One (1) Month.

The primary outcome is the number of eyes with slit-lamp findings of epithelial edema, graded from 0 to 4 at Baseline (After lens dispensing). The registry lists 16 outcome measures and 0 analyses, and does not report a numerical primary outcome result or comparative estimate. The safety listing reports 0 serious adverse events and 0 deaths in each arm; other adverse events affected 7 participants in Sapphire and 2 in Pearl.

The registry states that the study results were not used for design validation of the investigational contact lens. A statistical conclusion about the primary comparison cannot be drawn from the posted results.