Ocular Adaptation and Visual Performance for Accommodative Contact Lens: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ocular Adaptation and Visual Performance for Accommodative Contact Lens (NCT02923232), a na na study. The primary outcome is Monocular Refractive Power.

2. Clinical Question

The primary outcome is a continuous measurement in diopters, described as a mean with standard deviation. Participants were to wear the test lens and look at different downward angles while an open-field auto refractor measured the refractive power of the lens/eye combination. The registry summary also refers to visual-acuity testing across luminance levels and viewing distances or angles, but the primary outcome listed is monocular refractive power.

This is a measurement question about performance under the described wearing and viewing conditions, not a comparison of the lens with another treatment. The record lists 52 participants as the enrollment and identifies Pacific University as sponsor. It does not report outcome estimates, participant-level results, or analyses. The observed refractive power and the degree of variation between participants therefore cannot be assessed from the registry record.

3. Trial Design

The registry classifies this study as a single-group device study of an accommodative contact lens. Allocation is recorded as NA and masking as NONE. No comparator arm is listed, so the study is not a randomized comparison and cannot by itself estimate a contrast between the lens and a control condition. The registry lists an enrollment of 52; it does not report how many participants contributed usable outcome measurements.

The intended population was presbyopes who require distance optical correction. The intervention was a test contact lens made from traditional hydrogel material, with an internal cavity described as allowing deformation to increase refractive power at a downward angle. The primary measurement was planned after 30 mins of wearing, with the timeframe specifically described as non-dispensing. Participants would look at different downward angles while an open-field auto refractor measured the refractive power of the lens/eye combination.

The study start is recorded as 2014-11, and primary completion as 2020-03-01. Its status is TERMINATED. The reason for termination, whether recruitment or measurement stopped before the recorded enrollment, and whether any follow-up continued are not reported in the registry record. Phase is recorded as NA.

The registry lists 2 outcome measures and 0 analyses. The primary outcome is described, but details and results for the other outcome measure are not reported in the registry record. The protocol, statistical analysis plan, sample-size justification, interim analyses, and methods for handling repeated measurements are not reported in the registry record. These omissions limit what can be concluded about how the planned measurements were intended to be summarized.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: Subjects were recruited in 3 separate iterations. They were not assigned to different groups, and were tested with the same test lens with minor modification. This is considered a phase 1 study.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Presbyopes who require distance optical correction

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.

Population: Presbyopes

6. Primary Endpoint

The registry lists the primary outcome as Monocular Refractive Power, measured over 30 mins of wearing; non-dispensing..

The primary endpoint is monocular refractive power, measured in diopters. The registry describes it as the mean, with standard deviation as the measure of dispersion. Participants were to wear the test lens for 30 mins without dispensing, look at different downward angles, and have the refractive power of the lens/eye combination measured with an open-field auto refractor.

In general, refractive power describes the optical power of a lens or optical system. A diopter is the unit used for that power. A monocular measurement refers to measurement for an individual eye rather than a binocular measurement combining both eyes. The registry’s endpoint therefore targets an optical measurement under the specified lens-wearing and viewing conditions. It is not itself a direct measure of visual acuity, comfort, or longer-term use.

A mean can describe the central value of a continuous outcome across measured participants. A standard deviation describes how dispersed individual measurements are around that mean. Both are needed to understand the distribution in broad terms: a mean alone does not show how similar or variable the measurements were. The registry record does not report the mean, standard deviation, number analyzed, or results by viewing angle. The endpoint’s observed level and variability therefore cannot be described from the registry record.

The registry also gives a broader summary involving visual-acuity tests at different luminance levels and viewing distances or angles. However, the named primary endpoint is refractive power, and the record does not report how that endpoint relates to any visual-acuity outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a continuous primary outcome, summarized as a mean with standard deviation. It does not report an analysis method or any outcome analysis. The following statistical explanations are general; they describe what common summaries and methods mean, not what was necessarily done in this study.

What does a mean describe?

In general, the mean is the arithmetic average of observed measurements. For a continuous measurement such as refractive power, it gives a central summary on the same measurement scale as the outcome. It does not show the shape of the measurements, whether values cluster closely, or whether a small number of unusual observations influence the average. The registry record does not give the mean for this endpoint.

What does the standard deviation describe?

In general, the standard deviation describes the spread of measurements around their mean. A larger standard deviation indicates greater dispersion in the observed values, while a smaller one indicates that values are more concentrated around the mean. It is not the same as the standard error or a confidence interval. The standard deviation for the registered endpoint is not reported in the registry record, so the amount of observed variation cannot be assessed.

How would measurements at different angles affect analysis?

The endpoint description says participants would look at different downward angles. If multiple measurements were taken from each participant, observations from the same person could be related rather than independent. In general, methods for repeated or correlated measurements account for that dependence; treating correlated readings as unrelated can misstate uncertainty. The registry does not report the number or arrangement of readings, whether measurements at different angles were analyzed separately, or how any within-participant correlation was handled.

What does a confidence interval add?

In general, a confidence interval presents uncertainty around an estimate under a specified statistical method and its assumptions. It helps distinguish the estimated central value from the precision with which that value is known. A narrow interval represents greater precision than a wide interval, all else being equal. A confidence interval is not a range containing a fixed proportion of individual measurements; that is a different kind of summary. No confidence interval or precision estimate is reported for the primary endpoint.

Why might distributional assumptions matter?

In general, methods based on a normal approximation work best when their assumptions are reasonably compatible with the data and analysis. A continuous outcome may be summarized by a mean and standard deviation, but those summaries alone do not establish that a particular model is suitable. If measurements are strongly skewed, contain influential extreme values, or are correlated within participants, an analysis may need methods that address those features. The registry record does not report distribution checks, model diagnostics, transformations, or a chosen analysis model.

What do the planning assumptions mean?

The registry’s stated planning assumptions describe illustrations using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The target effect is expressed as a stated fraction of the observed effect. In general, a significance level is a design choice governing the threshold used for a statistical test under its assumptions; a two-sided test considers departures in either direction. Equal allocation refers to assigning the same planned number of participants to each of two groups. A normal approximation uses properties of the normal distribution to estimate a planning quantity.

For continuous outcomes, the planning results are described as participants per arm. They are hypothetical sample-size calculations, not observed power and not an account of how many participants were analyzed. The assumptions refer to two arms, while the registry lists a single-group study. The protocol’s own sample-size justification and the rationale for these planning assumptions are not reported in the registry record. Because no observed endpoint estimate is reported, the effect on which the illustrations are based cannot be examined against posted results.

Can a recalculation substitute for the sponsor analysis?

In general, a recalculation from summary statistics is an unadjusted calculation and may differ from a sponsor’s analysis if the sponsor used an adjusted model, a different analysis population, or different handling of repeated measurements. No outcome analyses or sponsor estimates are listed in the registry record, so there is no posted analysis to compare with a recalculation. No recalculated effect estimate can be interpreted as a registry result.

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("Accommodative Contact Lens")
n   <- c(52)
m   <- c(-1.5)
sp  <- c(2.42)
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  Accommodative Contact Lens  52  -1.500  2.420  -2.174  -0.826

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures and identifies monocular refractive power as the primary outcome. The other outcome measure’s details are not reported in the registry record. The record lists 0 analyses, so it does not provide results for either outcome or describe which analyses, if any, were performed.

In general, multiplicity arises when multiple outcomes, time points, subgroups, or statistical tests are considered. Testing many questions can increase the chance of at least one apparently notable result by chance. Statistical plans may address this through a prespecified primary outcome, a hierarchy of tests, or an adjustment to the testing procedure. The registry record does not report a multiplicity strategy, a hierarchy for the 2 outcomes, or any test results. No conclusion about multiplicity-adjusted evidence can therefore be drawn.

The registry does not report how missing measurements were handled, how many participants had missing data, or whether incomplete records were excluded or otherwise addressed. In general, missingness can affect both the representativeness of an analyzed group and the precision of estimates. The direction and size of any effect depend on why measurements are missing and on the analysis approach; those details are not reported in the registry record.

The record gives an enrollment of 52 but does not identify an analysis population, an analyzed sample size, or an intention-to-treat or per-protocol population. Those terms describe different rules for deciding which participants contribute to a given analysis. Without a stated population and participant flow, enrollment cannot be treated as the count analyzed. The statistical analysis plan and any interim analyses are not reported in the registry record.

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.

The registry reports 0 serious adverse events among 52 participants listed as at risk in the Accommodative Contact Lens group. It also reports 0 other adverse events among 52 listed as at risk, and 0 deaths. No top serious adverse-event terms are listed.

These figures describe the adverse-event fields in the registry record. They do not show how adverse events were defined, how events were collected, or over what detailed observation period they were assessed. The intervention description specifies 30 mins of wearing for the primary measurement, but the record does not clarify whether the adverse-event observation period was limited to that measurement timeframe.

In general, a count of zero recorded events is not proof that an event is impossible or that no unrecorded event occurred. Interpretation depends on the completeness and duration of safety follow-up and the number of participants actually assessed. Although 52 are listed as at risk, the record does not provide additional safety follow-up details or a narrative description of monitoring. These counts should therefore be read as registry-reported event counts, not as a comprehensive characterization of safety.

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

The registry record establishes that a study of an accommodative contact lens was registered as a single-group device study in presbyopes who require distance optical correction. It identifies monocular refractive power as the primary endpoint and describes measurement after 30 mins of non-dispensing wear at different downward angles. It also records an enrollment of 52 and a TERMINATED status.

The record does not report outcome analyses or estimates. It therefore does not establish the mean refractive power observed, the variability of measurements, or how measurements differed across angles. Nor does it establish a comparative effect, because no control group is listed. The absence of reported estimates should not be interpreted as evidence of no effect, just as the study description alone is not evidence of a particular effect.

The record does not state why the study was terminated, how many participants contributed measurements, or how the outcomes were analyzed. It does not report the detailed results for the second outcome measure. The safety fields list 0 serious adverse events, 0 other adverse events, and 0 deaths, but the record does not fully describe the observation period or event-collection process.

Any planning calculations are distinct from observed results. Their stated assumptions concern a two-arm design, whereas this registry record describes one group. Planning illustrations do not show that the planned precision was achieved, that a statistical test was conducted, or that an outcome was observed. Overall, the registry supports a description of the intended measurement and study status, but not a conclusion about the measured optical performance of the lens.

14. Why This Trial Matters Statistically

This study is statistically notable because its primary question is a measurement question in a single group rather than a randomized comparison. That distinction determines what the design can answer. Measurements after wearing the test lens can describe the recorded group if results are available, but without a comparator they cannot estimate a between-group contrast.

The endpoint also involves viewing at different downward angles. If a participant contributes multiple readings, the analysis must distinguish the number of readings from the number of independent participants. In general, correlated observations from the same participant carry less independent information than unrelated observations. The registry does not report how angle-specific observations were handled, so the implications for precision cannot be assessed.

The contrast between the listed single-group design and the stated two-arm planning assumptions is another important statistical issue. A planning calculation is only as relevant as its assumptions and intended use. Equal allocation between two arms does not describe the listed design, and a sample-size illustration cannot replace a protocol-based justification or an analysis of observed outcomes.

Finally, the registry lists 52 participants as enrolled but no analyses and no outcome estimates. This illustrates why enrollment counts, study status, and outcome reporting must be interpreted separately. A participant count alone does not establish that endpoint data were collected or analyzed, and a terminated status alone does not explain what happened. The record’s limited reporting makes transparent interpretation of design possible, but prevents statistical evaluation of the primary outcome.

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 principal limitation is the absence of posted outcome analyses. Although monocular refractive power is identified as the primary endpoint and the registry lists an enrollment of 52, no mean, standard deviation, confidence interval, or analysis population is reported. The record also lists 0 analyses. The amount and precision of any observed effect therefore cannot be assessed.

The single-group design has no listed control condition, and allocation is marked NA. This limits interpretation to a description of the group’s measurements if results become available; it does not support a direct comparison with another lens or condition. Masking is recorded as NONE, so the study was not masked according to the registry entry.

The primary measurement is described for 30 mins of non-dispensing wear. The registry record does not report longer-term measurements, so persistence over time cannot be evaluated from the stated endpoint. It also does not report how many participants completed the measurement, whether every participant contributed readings at each downward angle, or how missing readings were handled.

The study is marked TERMINATED, but the reason is not reported in the registry record. The record does not explain whether termination affected the planned enrollment or the availability of outcome data. It also does not provide the protocol, detailed analysis plan, sample-size justification, interim-analysis information, or details of the second outcome measure. These gaps prevent assessment of prespecification, analysis choices, and the completeness of results.

The stated sample-size planning assumptions refer to equal allocation between two arms, unlike the registered single-group design. No observed effect estimate is reported, making it impossible to assess the basis of those illustrations against an outcome. The results cannot be generalized beyond the population and measurement conditions described in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Ocular Adaptation and Visual Performance for Accommodative Contact Lens — NCT02923232.
• Registry record last updated 2023-05-03; status last verified 2023-04.
• Results first posted 2023-05-03.
• 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

NCT02923232 is a Pacific University study titled “Ocular Adaptation and Visual Performance for Accommodative Contact Lens.” The registry records a single-group device study with masking NONE, allocation NA, and an enrollment of 52. The population is presbyopes who require distance optical correction; the intervention is an accommodative contact lens.

The primary endpoint is monocular refractive power in diopters, summarized as a mean and standard deviation. It was to be measured with an open-field auto refractor after 30 mins of non-dispensing wear at different downward angles. The study started in 2014-11, has a primary completion date of 2020-03-01, and is marked TERMINATED.

The registry lists 2 outcome measures and 0 analyses. No primary outcome estimates or detailed analysis methods are reported in the registry record. Safety fields report 0 serious adverse events, 0 other adverse events, and 0 deaths.