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 Efficacy of Scleral Contact Lenses for Daily Wear for Regular and Irregular Refractive Errors Compared to Habitually Worn Scleral Lenses (NCT02643095), a na na study. The primary outcome is The Primary Endpoint of the Study is the Overall Satisfaction and Desire to Continue Wearing the Study Lenses.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02643095 |
| Phase | NA |
| Condition | Scleral Lens Wearers |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 22 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Jennifer Fogt |
| Results posted | Yes |
2. Clinical Question
Population
People who already habitually wear scleral contact lenses, described in the registry record as scleral lens wearers. The recorded enrollment was 22. The registry record does not report further eligibility details or a separate description of the population included in the primary-endpoint analysis.
Intervention
A scleral contact lens with a new design, made from a material described as already widely available. Investigators fit the study lens and assessed it after fitting, at one week, and at 1 month.
Comparator
The title frames the question against habitually worn scleral lenses. However, the recorded model is single group and allocation is listed as NA. A randomized or parallel control group is not recorded, and the registry record does not describe a formal comparative analysis.
Primary question
At 1 month after the study lens was dispensed, how many participants had overall satisfaction and a desire to continue wearing the study lenses? The registry record names this as the primary endpoint but does not report its observed count.
This question concerns participants’ reported overall satisfaction and willingness to continue wearing the study lenses. It is not, as recorded, a question about a measured change in vision, lens comfort on a particular scale, or a difference between randomized groups. The registry record identifies the participants as people who already wore scleral lenses, so the study evaluates a new lens in that context. Although the title mentions habitual lenses as a comparator, the recorded single-group design does not establish a like-for-like control comparison. It also does not say whether investigators collected paired measurements under both lens conditions or how any such measurements would be compared. Those details are not reported in the registry record.
3. Trial Design
The registry record identifies this as a completed study with a single-group model. It lists allocation as NA and masking as NONE. The recorded enrollment is 22, and the condition is scleral lens wearers. The intervention is a scleral contact lens, classified as a device. The description says the participants already habitually wore scleral contact lenses and that investigators fitted the study lens. Assessments were planned after fitting, at one week, and at 1 month.
The title describes the study as comparing daily wear of study scleral lenses with habitually worn scleral lenses. That wording should be distinguished from the design information: the model is single group, and the allocation field does not record assignment to intervention and control arms. The registry record therefore does not describe a randomized comparison or a separate control group. It also does not report a comparison method or explain whether participants’ habitual lenses were assessed as a within-participant comparator. A direct comparative effect cannot be inferred from the title alone.
The primary endpoint is specified at 1 month after the study lens is dispensed. The registry record lists one outcome measure and no analysis entries. The planned assessment schedule and the outcome definition are not themselves evidence that the endpoint was measured or that a result was analyzed. The primary-endpoint count, analysis population, and handling of participants without a recorded response are not reported in the registry record.
The record gives a study start date of 2016-01-26 and a primary completion date of 2016-08-08, and lists the status as completed. It does not report the original sample-size justification, protocol details beyond the recorded descriptions, or a statistical analysis plan. Completion status describes the registry status; by itself, it does not supply the missing outcome result or establish what analyses were conducted.
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
| Stage | Lens Fitting/Evaluation |
|---|---|
| STARTED | 22 |
| COMPLETED | 21 |
| NOT COMPLETED | 1 |
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 | Lens Fitting/Evaluation |
|---|---|---|
| Participants analysed | 22 | |
| Age, Customized: Age 18 or older | Participants | 22 |
| Sex: Female, Male: Female | Participants | 9 |
| Sex: Female, Male: Male | Participants | 13 |
| Race and Ethnicity Not Collected | Participants | — |
6. Primary Endpoint
The registry lists the primary outcome as The Primary Endpoint of the Study is the Overall Satisfaction and Desire to Continue Wearing the Study Lenses, measured over 1 month after lens is dispensed.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants with overall satisfaction and a desire to continue wearing the study lenses, assessed at 1 month after lens dispensing. Its unit is participants, and the registry describes it as a count. This is a binary-type outcome at the participant level: each person either meets the stated satisfaction-and-desire definition or does not, assuming the endpoint was assessed according to that definition. The registry record does not give additional scoring rules, a questionnaire, or a threshold for deciding whether a participant meets the endpoint.
A count can communicate how many participants met the stated definition, while the total number assessed would provide the context needed to interpret that count. The registry record does not report the primary-endpoint count or the number of participants with an evaluable response, so the observed result and its precision cannot be described. The enrollment count is not a substitute for the endpoint denominator: the number enrolled does not establish how many completed the assessment or had usable endpoint data.
This endpoint is used because the stated study question includes overall satisfaction and desire to continue wearing the study lenses. It captures those reported judgments rather than a direct clinical measurement. In general, a participant-reported endpoint can be useful for describing acceptability from the participant’s perspective, but its interpretation depends on how the question was asked and how missing or ambiguous responses were handled. Those details are not reported in the registry record. The endpoint also does not, by itself, establish a difference from habitual lens wear, because a comparative result and its analysis are not reported.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the primary question and its assessment time, but it does not report the primary-endpoint result. In particular, it gives no count of participants who were satisfied and desired to continue wearing the study lenses, no endpoint denominator, and no estimate of uncertainty. It is therefore not possible to describe the observed level of satisfaction or how precisely it was estimated from the registry information.
The recorded enrollment is 22, but this is the number enrolled, not a reported number with an endpoint response. The record does not say how many participants received a study lens, attended the 1-month assessment, or contributed data to the primary endpoint. Those distinctions matter for a participant count: a numerator without its corresponding analysis denominator cannot describe the frequency of the endpoint, and enrollment alone cannot fill that gap.
The title’s comparison with habitually worn lenses should also be read in light of the design fields. The registry records a single-group model and allocation as NA. It does not report a randomized comparator arm or a comparative analysis. Consequently, the registry information does not support a statement about a difference between study and habitual lenses. Nor does it establish whether the comparison was intended to be within participants; that approach and its analysis are not reported in the registry record.
The registry lists one primary outcome measure and zero analysis entries. This means no statistical analysis results are recorded in the analysis information. It does not show whether investigators conducted analyses outside the registry or whether additional results exist elsewhere. The record does not report a confidence interval, a p-value, or an adjusted estimate for the primary endpoint. These should not be inferred from the completed status or the enrollment count.
In general, a confidence interval describes the uncertainty around an estimate under the assumptions of the analysis; it does not repair an absent result or account automatically for biases in study design. Because no endpoint estimate or interval is reported, the precision of the primary finding cannot be assessed. Likewise, a p-value would address a specified statistical hypothesis under a model, but no such result or hypothesis test is recorded.
The posted safety figures are distinct from the primary endpoint. The registry reports zero serious adverse events among 21 at risk in the lens fitting/evaluation group, one other adverse event among 21 at risk, and zero deaths. These are descriptive counts. The record does not report inferential comparisons or additional detail about event type in the listed serious-event terms. They do not provide evidence about the unreported satisfaction endpoint.
Any planning illustration based on an observed effect is not an observed-power result and is not the trial’s original sample-size justification. The registry record does not report that justification. Where a planning calculation uses a hypothetical fraction of an effect, its output describes assumptions for planning rather than what occurred in this study. For this single-group record, equal allocation between arms is not a description of the recorded design.
9. Statistical Methods Explained
The registry describes a participant count for a binary-type endpoint. For each participant with an evaluable response, the endpoint definition distinguishes those who report both overall satisfaction and a desire to continue wearing the study lenses from those who do not meet that definition. The registry record does not provide the underlying questionnaire or operational rules, so it is not possible to judge how responses were classified or whether the definition was applied consistently.
What does a participant count describe?
A count is the number of people meeting an outcome definition. For interpretation, that count is ordinarily considered alongside the number of people assessed. The enrollment of 22 is recorded, but the endpoint numerator and the number assessed at 1 month are not reported in the registry record. It would be inappropriate to treat all enrolled participants as endpoint respondents without evidence that each contributed data.
A count is also different from a comparative effect. A comparative analysis requires a defined contrast, such as a difference between groups or a within-participant contrast, together with a method for estimating it. The registry records a single-group model and allocation as NA. Although the title refers to habitual lenses, the record does not specify a formal contrast or provide a comparative estimate. No unadjusted re-calculation is available from the posted summary statistics because the primary outcome summary is not reported.
How would uncertainty ordinarily be expressed?
In general, an interval estimate pairs an outcome estimate with a range of values compatible with the data and the stated statistical method. Its interpretation depends on the sampling model and on the data included. For a participant count, precision cannot be evaluated from the count alone; the denominator and the analytic method are also relevant. Since neither the endpoint count nor its analysis is reported, no interval can be interpreted for this outcome. A confidence interval would not resolve questions about missing participants, endpoint measurement, or the suitability of a comparator.
In general, a hypothesis test evaluates data against a specified null hypothesis using assumptions about how the observations arise. A p-value is not the probability that a treatment works, nor does it describe the size or practical importance of an effect. The registry record has no analysis entries and does not report a p-value or a test for the primary endpoint. The absence of a recorded test should not be replaced by a test inferred from the study title or design summary.
What do the design fields imply for analysis?
A single-group design does not record assignment to a separate concurrent control group. The allocation field is NA, and masking is NONE. These entries do not establish that participants or investigators were unaware of the lens being evaluated; the record explicitly lists no masking. Without a documented comparator analysis, a result in this group would describe the observed group, not a randomized between-group treatment effect. Whether participants served as their own comparator is not reported in the registry record.
In general, repeated observations on the same participant are related rather than independent. If an analysis uses multiple assessments from a participant, it needs to account for that relationship. The record mentions assessment at one week and 1 month, while the primary endpoint is set at 1 month. It does not report an analysis of repeated measurements or specify whether the earlier assessment contributes to the primary analysis. No assumptions about the statistical model for those assessments can be made from the schedule alone.
How should planning calculations be read?
The stated planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. The assumptions also distinguish total events for time-to-event calculations from participants per arm for other calculations. These are planning conventions, not evidence that the study used that design or that a corresponding analysis was conducted. The recorded trial is single group, and its primary endpoint result is not reported.
In general, sample-size calculations depend on the assumed effect, variability or event frequency, significance level, power target, allocation, and analysis method. When an illustration uses a fraction of an observed effect, it asks what planning would look like under that hypothetical effect size; it does not show the probability that this completed study detected an effect. Such calculations are not observed power, and they cannot be treated as the original protocol rationale unless the registry record documents that role. The original sample-size justification is not reported in the registry record.
Over-dispersion is a general concern when count data vary more than a chosen model expects; ignoring it can make uncertainty estimates too narrow. The primary endpoint is a participant count, but the registry does not report a fitted model, repeated count structure, or dispersion estimate. There is no basis in the record to say that over-dispersion was tested, present, or relevant to the actual primary analysis. A general statistical concern should not be presented as a finding about this trial.
Finally, analysis populations can differ from enrollment. An intention-to-treat population, a treated population, and a population with complete endpoint data answer questions under different inclusion rules. The registry record does not state which population was used for the primary endpoint or how withdrawals and incomplete responses were handled. Accordingly, the endpoint’s analysis population and the assumptions behind any potential estimate are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one outcome measure and zero analysis entries. It does not report a statistical analysis plan, a hierarchy of outcomes, or any correction for multiple testing. With one listed primary outcome measure, it is not possible to determine whether other endpoints or exploratory analyses were considered outside the registry record. The record does not report how multiplicity was addressed, if it was relevant to analyses actually conducted.
Missing-data handling is also not reported. The enrollment count of 22 does not establish how many participants completed the 1-month assessment or had an evaluable response. The record does not state whether missing endpoint values were excluded, imputed, or handled by another method. It likewise does not report withdrawal counts or reasons for missing assessments. These omissions limit interpretation because the people with available responses may not necessarily represent everyone enrolled.
The analysis population is not reported in the registry record. No rule is given for including participants who did not receive a study lens as intended, missed an assessment, or lacked a response to the satisfaction question. The record therefore does not support labeling the primary analysis as intention-to-treat, per-protocol, or complete-case. These are distinct analysis choices in general; the choice actually used cannot be inferred.
The registry records no analysis entries for the primary outcome. Thus it provides neither a documented multiplicity strategy nor a documented missing-data strategy for that analysis. These items are not evidence that the investigators did or did not use a particular method; they are details not reported in the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Lens Fitting/Evaluation | 0 | 21 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Lens Fitting/Evaluation | 0 of 21 |
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 |
|---|---|
| Lens Fitting/Evaluation | 1 of 21 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Lens Fitting/Evaluation |
|---|---|---|
| punctate keratitis | Eye disorders | 1 of 21 |
For the lens fitting/evaluation group, the registry reports zero serious adverse events among 21 participants at risk for serious events. It reports one other adverse event among 21 participants at risk for other events, and zero deaths. The record lists the serious-event term list as empty. These are the registry’s event counts and at-risk denominators; they are not estimates of comparative risk.
The enrollment was 22, while the adverse-event figures give 21 at risk in each category. The registry record does not explain this difference or state why one enrolled participant is not included in those at-risk counts. It also does not provide detail about the other adverse event in the information recorded. The two at-risk counts are reported separately; the record does not explain whether the underlying participant sets are identical.
In general, a zero count means no events of the specified type were recorded in the stated group and risk set. It does not establish that the true event risk is zero, particularly when the number at risk is limited. The registry record does not give an interval estimate or a comparator group for safety. These counts should therefore be read descriptively, without interpreting them as proof of safety or as evidence of a difference from habitual lens wear.
12. What the Result Does, and Does Not, Mean
The registry record documents a study of a newly designed scleral contact lens in people who already habitually wore scleral lenses. The intended primary outcome was the number of participants reporting overall satisfaction and a desire to continue wearing the study lenses at 1 month after dispensing. The study is listed as completed, with enrollment of 22 and a single-group model.
The central outcome result is not reported in the registry record. There is no posted count of participants meeting the primary endpoint, no denominator for the endpoint assessment, and no statistical analysis entry. As a result, the record does not show the observed satisfaction response or its precision. It also does not support a conclusion about how the study lens compared with participants’ habitual lenses. The title’s comparator wording does not replace a reported comparison method or result.
These absences do not demonstrate that no outcome data were collected or that no analysis was performed outside the registry. They mean that those results and methods are not reported in the registry record. The completed status indicates the recorded study status, not the availability or direction of an outcome finding.
The safety information reports zero serious adverse events among 21 at risk, one other adverse event among 21 at risk, and zero deaths. These counts are descriptive and are not accompanied by a comparative analysis or uncertainty estimates. They should not be read as establishing the absence of risk.
In general, a study’s observed outcomes describe the participants and procedures actually assessed; a controlled comparison requires a defined comparator and analysis. Here, the record does not provide the primary endpoint result or such a comparative estimate. It therefore cannot establish the magnitude, direction, or precision of a difference between study and habitual lenses, nor can it establish a causal effect. Those conclusions are not supported by the registry information recorded.
13. Why This Trial Matters Statistically
This record illustrates why a trial title and a design description need to be read together. The title frames a comparison with habitually worn scleral lenses, while the design fields identify a single group and allocation as NA. Those details are not interchangeable: a comparator named in a title does not establish that a controlled contrast was conducted or analyzed. The distinction is important when deciding what kind of statistical claim a study can support.
The endpoint also makes clear that outcome definition and outcome reporting are separate requirements. The registry names a participant-level satisfaction and desire-to-continue outcome at 1 month. However, it does not report the endpoint count, its denominator, or an analysis. Knowing the endpoint question does not reveal the observed response, and the enrollment count cannot substitute for endpoint data.
The record further shows why status and results should not be conflated. It is listed as completed, but the primary result and analysis details are not reported. In statistical reading, completion alone does not establish that outcomes were available, that a planned analysis was completed, or that any particular conclusion followed.
Finally, the recorded safety counts and the primary efficacy endpoint answer different questions. Descriptive event counts do not supply an estimate for satisfaction, and the absence of a serious-event count in this record does not provide a comparison with habitual lens wear. Keeping endpoints and designs distinct helps readers avoid extending the evidence beyond what the registry record documents.
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 registry record contains limited information for evaluating the primary outcome. It names the satisfaction-and-desire-to-continue endpoint and its 1-month timeframe, but does not report the observed count, the number assessed, or the analysis population. It also does not provide the measure or questionnaire used, response rules, or a plan for incomplete responses. Without these details, neither the result nor its precision can be assessed.
The title refers to habitual lenses, but the design is recorded as single group with allocation NA. A formal comparator analysis, including whether the comparison was within participants, is not reported. Masking is listed as NONE. The record does not describe additional procedures that might affect outcome assessment or explain how subjective responses were collected.
The registry lists one outcome measure but no analysis entries. It does not report an analysis plan, sample-size justification, multiplicity approach, missing-data method, or analysis population. The planning assumptions describe equal allocation between two arms, although the recorded study model is single group; these assumptions do not establish the trial’s design or original planning rationale.
For safety, the record reports 21 participants at risk in each adverse-event category despite enrollment of 22, without explaining the difference. It reports one other adverse event but does not provide further event detail in the listed information. These limitations restrict the interpretation of both the primary endpoint and the safety counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Efficacy of Scleral Contact Lenses for Daily Wear for Regular and Irregular Refractive Errors Compared to Habitually Worn Scleral Lenses — NCT02643095.
- Registry record last updated 2023-12-06; status last verified 2023-11.
- Results first posted 2018-09-13.
- 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, single-group study of a scleral contact lens for people who already habitually wore scleral lenses. The study lens is described as having a new design and using a material already widely available. Investigators fitted the lens, with assessments planned after fitting, at one week, and at 1 month. Enrollment was 22; allocation is listed as NA and masking as NONE.
The primary endpoint was the number of participants with overall satisfaction and a desire to continue wearing the study lenses at 1 month after dispensing. The registry record does not report the endpoint count, denominator, or analysis. It lists one outcome measure and zero analysis entries. Although the title refers to habitual lenses as a comparator, a formal comparative analysis is not reported.
For lens fitting/evaluation, the record reports zero serious adverse events among 21 at risk, one other adverse event among 21 at risk, and zero deaths. The study status is completed, with start date 2016-01-26 and primary completion date 2016-08-08.