Contact Lens Adaptation in Neophytes: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Contact Lens Adaptation in Neophytes (NCT02148263), a randomized na study. The primary outcome is Between-Group Difference in Eye Comfort as Measured by the Ocular Surface Disease Index (OSDI).

2. Clinical Question

The study addressed a routine question in contact-lens practice: whether new wearers should build up their wearing time gradually or begin with full-time wear. The registry summary says practitioners commonly advise gradual increases over the first days, while also noting that the practice lacks a scientific basis in the literature. The trial compared the two schedules in a randomized, parallel-group design.

Comfort and ocular health were assessed at baseline, one week, and two weeks using eye examinations and comfort surveys. Participants also kept a daily at-home comfort log using a visual analog scale. The primary endpoint singled out for the posted result was OSDI score at two weeks. The registry describes OSDI as an eye-comfort survey that measures dry-eye-related symptoms and vision-related functional effects; it is not the same measure as the daily comfort log.

The primary question is about a between-group comparison at the stated endpoint and time point. It is not, by itself, a question about change from baseline, every aspect of ocular health, or the full course of daily comfort during the study. The registry record does not report a more detailed primary hypothesis or specify a target population beyond new contact-lens wearers.

3. Trial Design

The registry identifies Contact Lens Adaptation in Neophytes as a randomized, single-masked, parallel-group study. It was sponsored by Ohio State University, enrolled 25 participants, and is listed as completed. The record gives a start date of 2014-05 and a primary completion date of 2019-08-20. It does not report the masking role or further details about how randomization was generated or implemented.

Both groups wore senofilcon A daily-wear contact lenses. The full-time group was instructed to begin with eight or more hours of wear per day on the first day. The graduated group followed a staged schedule: two hours on day one, four hours on day two, six hours on day three, eight hours on day four, and eight or more hours on day five. The comparison therefore concerns initial wearing schedules, not different lens materials.

The registry summary describes assessments at baseline, one week, and two weeks. Eye health and comfort were evaluated with a lighted microscope and comfort surveys; participants also completed a daily visual analog scale comfort log at home. All participants received instruction in wearing and caring for contact lenses. The summary says participants could receive a contact-lens prescription at the conclusion if they wished to continue wearing the study lenses.

The primary outcome was between-group difference in OSDI at two weeks. The arm-level results report nine participants in the full-time group and eleven in the graduated group for this outcome. These outcome counts are not the same as the overall enrollment figure. The registry record does not explain the difference, identify the analysis population, or describe the disposition of participants who are not represented in the arm-level results.

The listed secondary outcomes cover visual acuity, tear measures, ocular redness, eyelid findings, corneal staining, and end-of-day comfort. The record lists 10 outcome measures, 12 analyses, and nine posted secondary outcomes. It does not report a formal sample-size justification, the planned allocation ratio, or an analysis plan detailed enough to establish how all repeated assessments and outcomes were handled.

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 Between-Group Difference in Eye Comfort as Measured by the Ocular Surface Disease Index (OSDI), measured over 2 weeks.

The primary endpoint was between-group difference in eye comfort measured by the Ocular Surface Disease Index at two weeks. OSDI is a questionnaire scored from 0 to 100. As described in the registry, higher scores indicate greater disability. The instrument is intended to measure dry-eye symptoms and effects on vision-related function, and the record describes it as valid and reliable for assessing dry-eye disease and its impact.

Using a defined questionnaire gives researchers a structured way to compare participants’ reported symptoms and functional effects, rather than relying only on an informal description of comfort. That is useful in a study where the intervention is a wearing schedule and the outcome of interest includes the wearer’s experience. However, OSDI does not represent every possible aspect of contact-lens comfort or ocular health. The registry separately lists end-of-day comfort measured with a visual analog scale, along with clinical measures such as tear stability, tear volume, redness, and corneal staining.

The posted endpoint is a between-group comparison at the two-week time point. The registry record does not report a primary change-from-baseline measure or give a confidence interval for the group contrast. The scale’s direction matters for interpretation: a higher OSDI score corresponds to greater disability, not better comfort. The arm-level means are 10.8 for full-time wear and 16.3 for graduated wear, with standard deviations of 8.5 and 18.8, respectively. These summaries describe the observed participants and do not, on their own, establish the size or precision of a treatment effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is continuous: OSDI is recorded on a numeric scale, and the registry reports a mean and standard deviation for each arm. The sponsor’s listed inferential method, however, is the Wilcoxon (Mann-Whitney) test. These describe different aspects of the data. A mean summarizes the average score, while a standard deviation describes the spread of individual scores around that average. The Wilcoxon test uses ranks rather than directly testing a difference between means.

What does the Wilcoxon test compare?

In general, the Wilcoxon rank-sum test, also called the Mann-Whitney test, orders the observations across the groups and evaluates whether values in one group tend to rank higher or lower than values in the other. It can be useful when an analysis does not rely on a normal-distribution model for the outcome. Its interpretation is about the relative distributions of observed values. It is not automatically a test of medians, and it is not a direct test of the mean difference unless additional assumptions are made.

For this endpoint, the posted analysis is identified as Wilcoxon (Mann-Whitney), and the reported p-value is 0.83. The registry does not report the test statistic, a confidence interval for a rank-based effect, or enough detail to determine whether a continuity correction or another implementation choice was used. It also does not report whether the test was one-sided or two-sided. Those details should not be inferred from the method name alone.

Why distinguish the test from the arm summaries?

The posted means and standard deviations are descriptive statistics; they characterize the observed OSDI scores within each group. A rank-based test answers a different inferential question, using the ordering of observations rather than the group means. When distributions are skewed or contain influential observations, a rank-based comparison may respond differently from a mean-based analysis. General statistical interpretation should therefore keep the reported method and the descriptive summaries distinct.

Here, the full-time group has a reported mean of 10.8 and standard deviation of 8.5, while the graduated group has a mean of 16.3 and standard deviation of 18.8. Those numbers describe arm-level summaries only. The registry does not report individual observations, distribution plots, a median, or a confidence interval for the primary contrast. It is therefore not possible to assess the distributional shape from the posted summaries alone.

What does a p-value tell the reader?

In general, a p-value measures how unusual the observed test result, or a result more incompatible with the null model, would be if that model and the test assumptions were true. It is not the probability that the null hypothesis is true, and it is not the probability that the result occurred by chance. A large p-value does not prove that two groups are equivalent. It may arise when the groups are similar, when the data are variable, or when the available information is not sufficiently precise to distinguish possible differences.

The reported p = 0.83 should consequently be interpreted as the result of the specified Wilcoxon comparison, not as a measure of clinical importance. The registry does not report a clinically important difference threshold for OSDI, so the clinical relevance of any possible contrast cannot be assessed using such a threshold.

Why is a confidence interval useful?

In general, a confidence interval gives a range of estimates compatible with the observed data and the method used to construct it. It conveys precision and helps readers distinguish a narrowly estimated effect from one with substantial uncertainty. A p-value alone does not show that range. No confidence interval for the primary between-group comparison is reported in the registry record. The standard deviations are not substitutes: they describe person-to-person variation within arms, not uncertainty around the contrast.

What does over-dispersion mean in general?

Over-dispersion occurs when observed variability is greater than a statistical model assumes. It can make standard errors too small and tests too optimistic if the model does not account for the extra variation. This is a general consideration in statistical modeling, not a reported finding about this trial. The registry gives arm-level standard deviations, including 18.8 in the graduated group, but does not state that an over-dispersion model was considered or used. Since the reported primary test is rank-based, claims about a fitted mean model or its dispersion assumptions would not be supported by the record.

What can be said about planning calculations?

General sample-size illustrations based on an observed effect are planning exercises, not observed power and not evidence that the trial was designed around that effect. The registry record does not report the trial’s own sample-size justification, the target effect used in its planning, or whether its planned enrollment was based on a formal power calculation. It also does not report interim analyses or stopping rules. These omissions limit what can be concluded about the design rationale, but they do not change the meaning of the posted outcome summaries and Wilcoxon test.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Full-Time Senofilcon A Contact Lens Wear", "Graduated Senofilcon A Contact Lens Wear")
n   <- c(9, 11)
m   <- c(10.8, 16.3)
sp  <- c(8.5, 18.8)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Full-Time Senofilcon A Contact Lens Wear  9  10.800  8.500  4.266  17.334
CARM  Graduated Senofilcon A Contact Lens Wear  11  16.300  18.800  3.670  28.930

11. Analyses Reported by the Sponsor

The registry’s reported primary analysis is a Wilcoxon (Mann-Whitney) comparison between the full-time and graduated groups, with p = 0.83. The posted arm summaries give means and standard deviations, but the registry record does not report a numerical recalculated contrast or a confidence interval for that contrast. A mean-based recalculation, if available elsewhere, would answer a different statistical question from the sponsor’s rank-based test and should not be treated as an exact reproduction of it.

The registry record does not flag a discrepancy between sponsor and recalculated results. In any case, the sponsor’s listed analysis is the relevant reported inferential result: it identifies the test used and gives its p-value. The arm-level means remain useful descriptive information, but the registry does not provide the individual observations needed to reconstruct the Wilcoxon analysis independently. Nor does it provide a reported effect estimate that would permit direct comparison of the magnitude and precision of the two approaches.

Accordingly, the primary result should be described as the sponsor-reported Wilcoxon test with p = 0.83, alongside the arm-level summaries. It should not be rewritten as a test of a mean difference or assigned an unreported confidence interval.

12. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary OSDI outcome and a broader set of ocular-health and comfort outcomes. It reports 10 outcome measures, 12 analyses, and nine posted secondary outcomes. The secondary outcomes include visual acuity, tear stability, tear volume, redness, eyelid findings, corneal staining, and end-of-day comfort. Several outcomes concern distinct measurements, and the record does not explain how they were grouped into analyses or how results at different assessment times were handled.

When a study tests multiple outcomes or conducts repeated comparisons, the chance of at least one apparently notable result can increase. General statistical practice may address that issue by designating a primary endpoint, adjusting tests, or interpreting secondary analyses as exploratory. The registry record does not report whether any multiplicity adjustment was planned or applied, nor does it describe a hierarchy of outcomes beyond identifying the primary OSDI measure. The reported primary p-value should therefore be interpreted as the result of its stated test, without assuming an adjustment or a particular family of comparisons.

The record also does not report a missing-data method for the primary endpoint or secondary outcomes. It does not state whether missing scores were imputed, whether participants with incomplete measurements were excluded, or how repeated assessments were incorporated. The primary arm counts are nine and eleven, whereas overall enrollment is 25. The record does not give a participant flow account that explains this difference, so the reason for the outcome counts cannot be established.

The analysis population is not reported in the registry record. It is not possible to determine whether the posted comparison followed randomized assignment, included only participants with available OSDI scores, or used another population definition. Baseline outcome results and a detailed statistical analysis plan are also not reported. These gaps matter because missingness, analysis population, and multiple testing can affect how confidently a comparison is interpreted; they do not justify assuming a particular bias or analysis choice.

13. 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 0% reporting threshold.

The adverse-event figures report zero serious adverse events among the nine participants at risk in the full-time group and zero among the eleven at risk in the graduated group. The record also reports zero other adverse events in each group and zero deaths. No serious adverse-event terms are listed.

These figures describe what was recorded for the participants represented in the safety groups. They should not be read as proof that no adverse event could occur with either schedule. A zero count in a study of this size does not precisely establish the frequency of uncommon events, and the registry does not report confidence intervals for the safety figures. The record also does not explain the safety collection period in detail or provide further definitions of the adverse-event categories.

Safety counts should be kept separate from the primary OSDI comparison. The absence of recorded events in these groups does not determine whether the schedules differ in comfort, and the primary comfort result does not establish a safety profile. The posted figures are a description of reported events during the study, not a basis for broader conclusions beyond the observed participants.

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

The primary result concerns OSDI scores at two weeks among participants assigned to two initial contact-lens wearing schedules. The group means were 10.8 for full-time wear and 16.3 for graduated wear. Since higher OSDI scores represent greater disability, the graduated group’s mean was numerically higher in the posted summaries. The reported Wilcoxon comparison had p = 0.83. These results do not establish that the schedules are equivalent, nor do they show that a clinically important difference is absent.

A p-value alone does not quantify the magnitude or precision of a group difference. The registry does not report a confidence interval or a numerical effect estimate for the primary comparison. The reported standard deviations describe variation among participants within each group, not the uncertainty around the between-group contrast. A reader therefore cannot use the posted analysis to identify a well-defined range of plausible effects.

The primary endpoint is OSDI, not a comprehensive measure of every aspect of contact-lens experience. The study also assessed other ocular-health and comfort outcomes, but the registry record does not report results for all of them in the registry record for the primary result. The OSDI comparison should not be generalized to daily comfort logs, clinical examination findings, or other secondary endpoints without their results.

The trial was conducted among new contact-lens wearers, and the arm-level outcome counts were nine and eleven. The registry does not report detailed participant characteristics, the analysis population, or the handling of missing outcome data. These limits constrain both precision and generalizability. The findings describe the posted results from this study and do not by themselves settle the effects of these schedules in other groups, settings, or lens-wearing circumstances.

In short, the registry reports descriptive OSDI summaries and a Wilcoxon test that did not indicate a clear between-group difference under that analysis. It does not report enough information to establish equivalence, to estimate the range of compatible effects, or to draw conclusions about unreported outcomes.

15. Why This Trial Matters Statistically

This trial addresses a practical question about how new contact-lens wearers begin wearing their lenses: whether wearing time should increase gradually or begin at eight or more hours per day. The registry summary describes gradual escalation as common advice while noting the lack of a scientific basis in the literature for that practice. Random assignment makes the comparison relevant to evaluating the two schedules within the study, while the parallel-group design compares participants assigned to one schedule or the other.

Statistically, the result illustrates why a test, descriptive summaries, and precision estimates should be read together. The arm means differ numerically, but the reported inferential analysis is rank-based, and the registry does not provide a confidence interval or a numerical effect estimate. The p-value alone cannot show the size of a difference or rule out effects that may matter. It also cannot establish equivalence.

The record highlights the importance of transparent reporting beyond a headline test result. Enrollment is 25, while the primary endpoint counts are nine and eleven; the registry does not explain the difference or identify the analysis population. Information about missing data, multiplicity, and the design’s sample-size justification is also not reported. Those details are central to assessing how complete and precise the evidence is.

The study also places subjective comfort alongside clinical measures of ocular health. That distinction matters: an eye-comfort questionnaire, a daily visual analog scale, and clinical examination measures represent different outcomes. A result for OSDI should not be treated as a result for all dimensions of comfort or eye health. Clear outcome-specific interpretation helps prevent conclusions from extending beyond the measure actually analyzed.

16. 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 primary endpoint arm counts are nine and eleven, while the trial enrollment is 25. The registry record does not explain this difference, report a participant flow, or describe whether missing outcome data led to exclusions. Without those details, the composition of the analyzed groups and the completeness of follow-up cannot be assessed.

The record does not identify the primary analysis population or explain whether the comparison followed randomized assignment. It also does not provide baseline OSDI results, participant-level data, or a confidence interval for the primary contrast. As a result, readers cannot assess baseline balance, independently reconstruct the rank-based test, or judge the precision of an estimated group difference.

The registry lists multiple outcomes and analyses but does not report a multiplicity strategy. The primary endpoint is identified, but the record does not say whether secondary outcomes were prespecified in a hierarchy, whether adjustments were made, or how repeated measurements were treated. It also does not report the trial’s sample-size justification, interim analyses, or stopping rules. These details should be regarded as unreported rather than inferred.

The registry describes the study as single-masked but does not state who was masked or how masking was maintained. The available population description is limited to new contact-lens wearers, with no further eligibility or demographic details reported. These gaps limit assessment of possible measurement influences and the applicability of results to specific groups.

Finally, the primary result is one questionnaire outcome at two weeks. The study summary describes other assessment times and additional comfort and ocular-health measures, but the primary details do not include all corresponding results. Conclusions should remain specific to the posted OSDI analysis and should not be extended to unreported outcomes or follow-up findings.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: Contact Lens Adaptation in Neophytes — NCT02148263.
• Registry record last updated 2022-09-29; status last verified 2022-09.
• Results first posted 2022-08-22.
• 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.

20. Record Summary

Contact Lens Adaptation in Neophytes (NCT02148263) is listed as a completed, randomized, single-masked, parallel-group study sponsored by Ohio State University. The record gives enrollment as 25, a start date of 2014-05, and a primary completion date of 2019-08-20. It compared graduated senofilcon A wear with full-time senofilcon A wear in new contact-lens users.

The primary outcome was OSDI score at two weeks, with higher scores indicating greater disability. The full-time group had a mean of 10.8 (standard deviation 8.5; nine participants), and the graduated group had a mean of 16.3 (standard deviation 18.8; eleven participants). The reported Wilcoxon (Mann-Whitney) comparison had p = 0.83.

The registry does not report a confidence interval for the primary contrast, explain the difference between enrollment and outcome counts, or specify the analysis population and missing-data method. It also does not report a multiplicity strategy or the trial’s sample-size justification.