Maximizing the Initial Experience of a Neophyte Scleral Lens Wearer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Maximizing the Initial Experience of a Neophyte Scleral Lens Wearer (NCT04583579), a na na study. The primary outcome is Scleral Lens Application Time.

2. Clinical Question

3. Trial Design

The registry describes a single-group study of new scleral lens wearers, with enrollment listed as 17. Its stated goal is to learn about methods of applying scleral lenses and factors associated with completing application and removal training. The primary endpoint, however, is application time; the record lists subject method preference as a secondary outcome. Removal time or completion of training is not named as the primary endpoint.

Each subject tried all 5 application methods in a random order. This is a repeated-measures arrangement: a participant contributes attempts under more than one method, rather than being assigned to one method and compared with a separate control arm. The record lists allocation as NA, masking as none, and the model as single group. The random ordering of methods within subjects should not be confused with random allocation to separate study arms.

The listed methods are the DMV inserter with an open end, the DMV inserter with a closed end, three fingers, an O-ring, and a tea light candle with a DMV inserter. The application-time assessment is specified for the dispense visit at Hour 0 (Visit 2). The record lists the study as terminated, with a start date of 2021-02-23 and a primary completion date of 2023-06-01. It does not report why the study was terminated or whether termination affected data collection. The statistical analysis plan and details of the method-order procedure are not reported in the registry record.

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:

Analysis population for the primary outcome, as defined in the registry: Each subject tried all 5 methods.

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 Scleral Lens Application Time, measured over At Dispense Visit at Hour 0 (Visit 2).

The primary endpoint is the amount of time, in minutes, needed to apply scleral lenses to both eyes. The assessment is specified for the dispense visit at Hour 0 (Visit 2), and each subject tried each application method. The registry identifies the outcome as continuous and specifies the mean and standard deviation as its summary measures.

Application time is a direct measure of how long the application task takes under the tested conditions. Recording it for each method allows a comparison of typical task duration, while the standard deviation describes how much observed times vary around the mean. These summaries address different questions: a mean describes a central value, and a standard deviation describes spread among observations. Neither alone describes uncertainty in a method-to-method contrast.

For this within-subject design, the interpretation of method comparisons depends on the pattern of observations from the same subjects across methods. A comparison that accounts for this pairing can distinguish a method contrast from differences in participants’ usual application speed. The registry record does not provide the measured times, method-specific means or standard deviations, confidence intervals, or an estimated contrast. It is therefore not possible to describe the size or precision of the observed time differences from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean describe?

For a continuous endpoint such as application time, the mean is an arithmetic summary of the observed values. It provides a measure of central tendency: broadly, the mean time across the observations included in that calculation. The standard deviation describes the spread of those values around their mean. A small or large standard deviation has meaning only in the context of the observed measurements and the way they were collected. The registry specifies these summary measures but does not report their values for any method.

A mean is not the same as a method-to-method effect estimate. To compare methods, an analysis would need to define the contrast of interest and calculate it from the observed data. In a repeated-measures study, the observations from the same person are related. A method comparison should therefore reflect that within-person structure rather than treating every recorded attempt as if it came from an unrelated participant. The registry record reports one analysis but does not identify its statistical method or state how it handled repeated observations.

Why does the within-subject structure matter?

In general, people can differ in their usual speed at a task. When every subject tries each method, the data contain repeated observations from the same individual. An analysis that accounts for this pairing can focus on how a person’s time changes across methods, while accounting for stable differences in that person’s overall pace. An analysis that ignores the pairing may misrepresent the amount of information in the data, because observations from the same person are not necessarily independent.

The record says each subject tried the methods in a random order. In general, random ordering can distribute systematic order effects across methods rather than attaching one method consistently to an early or late attempt. It does not guarantee that learning, fatigue, or carryover is absent, nor does it show that those factors were included in the analysis. The registry does not report the ordering procedure, whether order effects were assessed, or how any such effects were handled.

What would uncertainty measures add?

In general, a confidence interval gives a range of values compatible with the data and the assumptions of the analysis. For a difference in application time, it would communicate both the direction and the precision of the estimated contrast. A p-value addresses how compatible the data are with a specified null hypothesis under an assumed statistical model; it does not give the size of the difference or its practical importance. The registry does not report confidence intervals or p-values for the primary endpoint, so neither the precision nor the statistical evidence for any contrast can be assessed.

The registry identifies application time as continuous and gives the mean and standard deviation as the endpoint summaries. It does not report the distribution of observed times. In general, if a continuous measure is strongly skewed or contains unusually large values, a mean and standard deviation may not fully convey its distribution. That is a general consideration, not a claim about the distribution in this study. The record also does not say whether model assumptions were checked or whether any alternative summaries or analyses were used.

How should planning calculations be read?

The registry’s planning assumptions describe an illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They state that the effect to detect is a specified fraction of the observed effect. These are planning assumptions, not evidence that the study used that design: the registered study is single group, and each subject tried all methods. The record does not report the fraction or any resulting sample-size values.

In general, a sample-size illustration estimates how many participants per arm might be needed under its stated assumptions to detect a target effect with a chosen power. Such an illustration is conditional on the effect size and statistical model used. It is not observed power and does not show that a study had a particular probability of success after the data were collected. The planning assumptions described in the registry also specify a two-arm allocation structure, which does not match the within-subject method-testing arrangement described for this study. The illustration should therefore be read as a planning calculation under its stated assumptions, not as a description of the actual trial design or a substitute for reported endpoint results.

More generally, statistical analysis requires a clear definition of the target contrast, the observations included, and the assumptions used to estimate uncertainty. For this study, the outcome definition and repeated-measures design are available, but the statistical plan, model, handling of order, missing-data approach, and method-specific results are not reported in the registry record. Without those details and the actual estimates, the registered endpoint cannot be translated into a quantitative comparison.

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("New Scleral Lens Wearers - DMV Inserter (DMV® Magi", "New Scleral Lens Wearers - DMV Inserter (DMV® Magi", "New Scleral Lens Wearers - Three Fingers (Patient'", "New Scleral Lens Wearers - O-ring (Hardware Store ", "New Scleral Lens Wearer - Tea Light Candle (Generi")
n   <- c(13, 13, 13, 13, 13)
m   <- c(75.2, 71.6, 51.3, 62.5, 63.9)
sp  <- c(20.7, 25.9, 38.5, 37.5, 35.7)
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  New Scleral Lens Wearers - DMV Inserter (DMV® Magi  13  75.200  20.700  62.691  87.709
CARM  New Scleral Lens Wearers - DMV Inserter (DMV® Magi  13  71.600  25.900  55.949  87.251
CARM  New Scleral Lens Wearers - Three Fingers (Patient'  13  51.300  38.500  28.035  74.565
CARM  New Scleral Lens Wearers - O-ring (Hardware Store   13  62.500  37.500  39.839  85.161
CARM  New Scleral Lens Wearer - Tea Light Candle (Generi  13  63.900  35.700  42.327  85.473

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures and identifies application time as the primary outcome and subject method preference as a secondary outcome. It also lists 1 analysis, but that count does not specify the analysis method, the contrasts tested, or whether any multiplicity procedure was used. The record does not report a testing hierarchy, adjustment for multiple comparisons, or a plan identifying which method contrasts were primary. With several methods, the number and selection of comparisons can affect how statistical evidence is interpreted; the registry does not provide enough detail to determine how that issue was addressed.

The registry does not report whether any application-time observations or preference responses were missing, nor how missing data were handled. It does not identify an analysis population or state whether participants with incomplete method attempts were included in any analysis. Those omissions are important in a repeated-measures design, because a participant may have observations for some methods but not others. No assumptions about completeness or the method used to address missingness can be made from the record.

The record also does not report a statistical analysis plan, prespecified contrasts, model covariates, or sensitivity analyses. These items are not necessarily absent from the research process; they are not reported in the registry record. The listed enrollment of 17 should not be assumed to be the analysis sample for every outcome. Without outcome counts and analysis-population definitions, the effect of incomplete records and the scope of the reported analysis cannot be evaluated.

12. 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.

For the New Scleral Lens Wearers group, the registry lists 17 at risk for serious adverse events and 0 affected. It also lists 17 at risk for other adverse events and 0 affected, with 0 deaths. These are the safety figures recorded for the study group; the record does not list any serious adverse event terms.

These counts should be read as registry-reported event counts, not as proof that no adverse events could occur or that every possible event was captured. The record does not give further detail about adverse-event definitions, collection procedures, follow-up completeness, or whether the counts cover all participants who entered the study. It also does not provide a separate event breakdown by application method. Because this is a single-group study in which subjects tried multiple methods, the listed figures do not provide a like-for-like safety comparison between methods.

The registry lists the study as terminated but does not report whether termination affected safety follow-up or event reporting. The recorded zero counts can be described as such; they do not establish a comparative safety profile or explain the reason for termination.

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

The registry establishes the study’s intended measurement: time in minutes to apply scleral lenses to both eyes, with each subject trying each of 5 methods in a random order. It also identifies a secondary outcome, subject method preference, and lists the study as single group with no masking. These details help define the question and the structure of the data that would be needed for a within-subject comparison.

The record does not report the primary outcome results or preference results. It therefore does not show which method was associated with a lower observed application time, whether any difference was small or large, or how precisely a difference was estimated. It cannot establish that a method was faster, slower, preferred, or equivalent to another based on the information in the registry record. No result should be inferred from the study objective or endpoint description.

The study design also does not amount to a comparison of separately randomized groups. Each subject tried all methods, and the order was randomized within each subject. This structure can be useful for comparing methods while accounting for differences in people’s usual pace, but interpretation still depends on the analysis of repeated observations, method order, and missing measurements. Those analysis details are not reported in the registry record.

The safety fields record 0 serious adverse events, 0 other adverse events, and 0 deaths, with 17 at risk for each adverse-event category. These are descriptive registry counts and do not constitute a comparison between methods. The enrollment listed is 17, while the number contributing to each outcome analysis is not reported. Thus, the most defensible interpretation is descriptive: the registry documents the question, methods, design, and recorded safety counts, but does not supply the outcome estimates needed to judge observed differences.

14. Why This Trial Matters Statistically

This study raises a useful statistical design issue: a participant can serve as their own reference when several methods are tested on the same person. This within-subject structure can make method comparisons more informative than a comparison that ignores individual differences in task speed. It also requires an analysis that recognizes that repeated observations from one person are related. The registry identifies the repeated testing, but does not report the analysis method used.

The endpoint is a practical continuous measure, application time, and the record specifies a mean and standard deviation. Those summaries describe central tendency and variability, but they do not by themselves answer whether methods differ. A contrast estimate and an uncertainty measure would be needed to describe the direction, size, and precision of a difference. Since the primary results are not reported in the registry record, the statistical question remains defined but unanswered by the available results.

The random ordering of methods is also important to consider. In general, when participants make repeated attempts, task familiarity or fatigue could vary across attempts. Random order can help avoid systematically tying a particular method to a particular position in the sequence, although it does not eliminate every possible order-related effect. Details about order generation and analysis are not reported.

Finally, the record illustrates why design, outcome definitions, and results must be read separately. A stated objective and a registered endpoint describe what a study set out to investigate; they are not evidence of an observed effect. The entry also lists planning assumptions based on a two-arm illustration, while its described method testing is within-subject. Keeping those design contexts distinct is essential when interpreting any planning calculation or considering what conclusions the study could support.

15. 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 main limitation for interpretation is that the registry record does not report primary endpoint results. There are no method-specific application-time summaries or estimated contrasts, and no confidence intervals or p-values. The registered outcome description alone cannot show the observed ordering of methods or the precision of any comparison.

The analysis details are limited. Although the record lists 1 analysis, it does not state the statistical method, the target contrasts, or whether the repeated observations from each participant were modeled as paired data. It does not describe how randomized order was generated or whether order, learning, fatigue, or carryover was considered. These are relevant design and analysis questions, not documented problems in the study.

The enrollment is listed as 17, but the record does not state how many participants contributed usable data to each outcome, whether every participant completed every method attempt, or how incomplete data were handled. The analysis population is not reported. The record also does not explain why the study was terminated, so the implications of that status for data collection and follow-up are unknown.

The registry lists subject method preference as a secondary outcome but does not report its results or assessment details. Multiplicity procedures and a prespecified testing hierarchy are not reported. Safety counts are available, but the record gives no event terms and no method-specific safety breakdown. Finally, the planning illustration uses a two-arm framework, whereas the registered endpoint describes each subject trying all methods; the illustration should not be mistaken for a description of the actual study design.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Maximizing the Initial Experience of a Neophyte Scleral Lens Wearer — NCT04583579.
• Registry record last updated 2024-07-18; status last verified 2024-07.
• Results first posted 2024-07-18.
• 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.

19. Record Summary

The registry record describes a single-group study of new scleral lens wearers, with enrollment listed as 17 and status listed as terminated. Each subject tried 5 scleral lens application methods in a random order. The primary endpoint was application time in minutes for both eyes at the dispense visit at Hour 0 (Visit 2), summarized by mean and standard deviation. Subject method preference was listed as a secondary outcome.

The record does not report application-time or preference results, the statistical analysis method, the analysis population, or the handling of missing data. It lists 0 serious adverse events, 0 other adverse events, and 0 deaths. The study’s objective and design are documented, but the registry results do not permit an assessment of method-specific application times or comparative precision.