Retinal Fundus Flavoprotein Fluorescence in Age Related Macular Degeneration: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Retinal Fundus Flavoprotein Fluorescence in Age Related Macular Degeneration (NCT06381596), a na na study. The primary outcome is Correlation Between FPF-intensity, FPF-heterogeneity and OCT Continuous Variables.

2. Clinical Question

The central statistical question is whether measurements from these imaging methods vary together in the study sample. A correlation describes the direction and strength of an association; it does not by itself establish that one measurement causes another, or that an imaging signal predicts later disease. The registry record does not report numerical primary results, so the direction, magnitude, and precision of the observed associations cannot be described from this record.

3. Trial Design

This completed study was registered as a single-group investigation of retinal fundus flavoprotein fluorescence in age-related macular degeneration. The recorded enrollment was 32. The study began on 2024-04-16, reached primary completion on 2025-05-27, and has a status of completed. The listed conditions are geographic atrophy and age-related macular degeneration.

Participants underwent FPF imaging with the OcuMet Beacon system. The arm is described as fundus autofluorescence imaging, and the record does not describe a second arm receiving a different procedure or a control intervention. Allocation is listed as not applicable, and masking is listed as none. Consequently, this is not a randomized or masked comparison of treatment groups. The study instead examines relationships among measurements collected in the same single-group setting.

The primary outcome is described as the correlation between FPF intensity, FPF heterogeneity, and continuous OCT variables. The outcome timeframe is up to 45 minutes. The registry description says that the analyses considered both FPF biomarkers and FAF/OCT variables, including areas of geographic atrophy, ellipsoid zone loss, and retinal pigment epithelium loss. Listed secondary outcomes include cross-sectional associations between FPF intensity and FAF area, between best corrected visual acuity and FAF area, and correlations involving FPF measures and participant variables.

The record lists 7 outcome measures and 12 analyses. It does not report a detailed recruitment process, eligibility criteria, visit schedule, eye-level analysis population, or the full statistical analysis plan. It also does not describe a sample-size justification for the study’s design. Any planning illustrations associated with the record should be understood as planning calculations, not as evidence about how many participants were actually observed or as a measure of observed power.

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 Correlation Between FPF-intensity, FPF-heterogeneity and OCT Continuous Variables, measured over up to 45 minutes.

The primary endpoint is a correlation coefficient describing the relationship between FPF intensity and FPF heterogeneity and continuous OCT variables. The record identifies areas of geographic atrophy, ellipsoid zone loss, and retinal pigment epithelium loss as relevant imaging variables. The stated timeframe is up to 45 minutes. The outcome description says Spearman’s rank coefficient was chosen because the sample contained a relatively small number of eyes and the data were not normally distributed according to Shapiro-Wilk tests evaluated at α=0.05.

In general, a correlation coefficient describes how two variables vary together. Spearman’s rank correlation uses the ordering of observations rather than requiring a straight-line relationship between the original measurements. It can describe a monotonic association: broadly, whether higher ranks in one measure tend to accompany higher or lower ranks in another. A correlation does not establish that changes in one measure cause changes in the other, nor does it establish how well a measure predicts future outcomes.

The registry record reports the planned metric and analysis rationale, but it does not report the numerical correlation estimates or their 95% confidence intervals. The magnitude, direction, and precision of the primary endpoint therefore are not reported in the registry record. The record also does not clarify the complete set of primary comparisons or how a specific coefficient corresponds to each pair of imaging variables.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Why use a rank correlation?

The primary outcome description specifies Spearman’s rank coefficient. In general, a rank correlation compares the relative ordering of observations on two measures. It can be useful when the relationship is monotonic but not necessarily represented by a straight line, or when data do not meet assumptions associated with commonly used parametric methods. The record says Spearman’s method was chosen because the number of eyes was relatively small and the data were not normally distributed, with normality evaluated using Shapiro-Wilk tests at α=0.05.

A rank-based approach does not make every other analysis concern disappear. Results can still be affected by the range and quality of the measurements, the number of independent participants, ties in ranked values, and the way measurements from the same person are handled. The registry record does not report the number of eyes contributing to each analysis, the distribution of the observed measurements, or the numerical correlation estimates. Those details would help readers evaluate the stability and interpretation of each coefficient.

What does the correlation describe?

In general, a correlation summarizes how two measured variables change together. A positive coefficient indicates that higher values or ranks in one measure tend to accompany higher values or ranks in the other; a negative coefficient indicates that higher values or ranks in one tend to accompany lower values or ranks in the other. The value’s magnitude describes the strength of the observed association on the chosen scale. Correlation does not establish a causal relationship, and it does not on its own indicate whether a measurement can classify disease, predict future change, or guide decisions.

The primary outcome connects FPF intensity and heterogeneity with continuous OCT variables. The record also refers to areas of geographic atrophy, ellipsoid zone loss, and retinal pigment epithelium loss. It lists secondary questions concerning FPF intensity and FAF area, best corrected visual acuity and FAF area, and FPF measures in relation to participant variables. Because the record does not report coefficients, confidence intervals, or p-values, readers cannot determine which relationships were strongest, their direction, or the uncertainty around them.

Why account for measurements from both eyes?

In general, measurements from two eyes belonging to one participant may be more alike than measurements from different participants. Treating every eye as independent when that dependence is present can make statistical uncertainty appear smaller than it is. The registry description explicitly notes this concern and says p-values were obtained using nonparametric bootstrap resampling at the patient level.

In a bootstrap procedure, the analysis repeatedly samples units from the observed data to assess how estimates vary. Resampling at the participant level is intended to keep measurements from the same person together, thereby respecting their grouping. The registry record does not report the number of resamples, the precise resampling implementation, or which estimates were accompanied by bootstrap-based p-values. It also does not give the number of participants with one or two eyes included. These details are not reported in the registry record.

How should the confidence intervals be read?

The primary outcome identifies a 95% confidence interval as its dispersion measure. In general, a confidence interval conveys the precision of an estimate under the assumptions of the statistical method. A relatively narrower interval indicates greater precision than a wider interval, while an interval that includes values compatible with different directions or magnitudes can leave substantial uncertainty about the association. A confidence interval does not mean that the true value has a 95% probability of falling in the specific calculated interval under the usual frequentist interpretation.

The record identifies the interval format but does not report the numerical bounds. The degree of precision therefore cannot be assessed. It also does not make clear whether intervals were calculated by the same patient-level resampling approach described for p-values or by another method. The confidence intervals should not be reconstructed from absent information.

What does the normality test contribute?

The outcome description says that Shapiro-Wilk tests were used to assess normality and evaluated at α=0.05. In general, a normality test evaluates whether data are inconsistent with a specified normal distribution; it does not prove that data follow a particular distribution. Its interpretation can depend on sample size and the data being tested. The record does not report the test statistics or p-values, so the exact diagnostic findings cannot be reviewed. The method statement reports the conclusion that the data were not normally distributed and the rationale for using Spearman’s rank coefficient.

What can be learned from the planning illustrations?

In general, a sample-size planning calculation estimates the number of participants or events that would be needed under specified assumptions to detect an effect. It is a planning exercise, not a statement about the probability that a completed study has found an effect. The record describes planning illustrations based on the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it says the effect to detect is a stated fraction of the observed effect. For non-time-to-event calculations, the illustration is expressed as participants per arm; for time-to-event calculations, it uses a total number of events.

Those assumptions describe hypothetical planning calculations and should not be mistaken for the design of this single-group imaging study. The record does not report a trial-specific sample-size justification. It also does not report numerical planning estimates in the information available for this analysis. Any planning figures must be interpreted as illustrations tied to their assumptions, not as observed power or as a substitute for the study’s actual estimates and confidence intervals.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 7 outcome measures and 12 analyses. The primary outcome description specifies correlations between FPF biomarkers and FAF/OCT variables, and the listed secondary outcomes include additional cross-sectional associations involving FPF intensity, FAF area, best corrected visual acuity, and participant variables. This set of analyses raises a general multiplicity concern: when many hypotheses are tested, the chance of at least one apparently unusual result can increase even if no single association is especially persuasive. That is a general statistical principle, not evidence that any particular result in this study is false.

The registry record does not report whether a multiplicity adjustment was planned or applied, how the primary comparisons were distinguished from exploratory analyses, or whether the 12 analyses represent all analyses conducted. The planned significance threshold mentioned in the outcome description is α=0.05 for the Shapiro-Wilk normality tests; the record does not identify a separate multiplicity strategy for the correlation analyses. Numerical p-values and confidence intervals are not reported, so the results cannot be reviewed in the context of the number of tests.

Missing-data handling is not reported in the registry record. The record does not state whether any measurements were unavailable, how missing eye-level or participant-level observations were handled, or whether analyses used complete cases or another approach. The analysis population for each outcome is also not reported. The enrollment count of 32 does not establish how many participants or eyes contributed to each specific analysis.

The record describes patient-level bootstrap resampling for p-values to account for correlation between eyes belonging to the same patient. It does not report further details about the bootstrap procedure or the analysis populations. These omissions limit assessment of how missingness, clustering, and multiple testing affect uncertainty and interpretation.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry lists 32 participants at risk in the fundus autofluorescence imaging group. It reports 0 serious adverse events and 0 other adverse events, with 0 deaths. These are the event counts recorded during the study; they describe what was reported among the participants at risk, not proof that no adverse events could occur.

In general, a count of zero observed events is different from evidence that the underlying risk is zero. The ability to characterize uncommon events depends on the amount of observation and the completeness of event collection. The registry record does not report a detailed adverse-event definition, surveillance procedures, observation duration for safety, or event-level narratives. It also does not provide separate safety results for different intervention groups, since this is a single-group study.

The reported counts should therefore be read narrowly: no serious events, other events, or deaths are recorded for the listed group in the registry record. They do not establish the absence of risk outside the study or settle safety questions that the study was not designed to answer. No further safety interpretation is supported by the reported figures.

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

This study addresses whether retinal fundus FPF measurements are associated with findings from other retinal imaging measures in people studied in the context of geographic atrophy and age-related macular degeneration. Its primary outcome is a correlation, and the registry description states that FPF intensity and heterogeneity are considered alongside continuous OCT variables. The broader study aim is to evaluate patterns of increased FPF in geographic atrophy and explore whether areas of cellular stress correspond to areas of disease identified by standard imaging.

Those aims are about measurement relationships. In general, finding a correlation can support the view that two measures tend to vary together in a sample. It does not show that one measure causes the other, that an imaging signal can detect disease before it occurs, or that an association will hold in a different population. A cross-sectional association also does not establish that one measurement predicts a future event. The registry record does not report a prospective prediction result or a comparison of clinical outcomes.

The study has no separate randomized control group and no masking. Therefore, it does not estimate a treatment effect or compare the effects of assigned interventions. The OcuMet Beacon is the named imaging device used for FPF imaging; the record does not describe it as a treatment. The study’s purpose, as described, is investigation of imaging patterns and associations.

Crucially, the registry record does not report numerical primary or secondary results. Without estimates, confidence intervals, or p-values, it is not possible to state which associations were observed, how large they were, how precisely they were estimated, or whether they met a statistical threshold. A stated analytical method and research aim are not a substitute for posted findings.

The record can establish the study’s enrollment, single-group design, imaging procedure, endpoint description, and stated analysis rationale. It cannot establish from the reported information whether FPF imaging identifies areas of concern before symptoms or disease occur, whether its measures add information beyond standard imaging, or what the clinical importance of any association might be. Those questions require results and supporting methods that are not reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically interesting because it treats retinal imaging as a set of related quantitative measurements rather than as a single result. Its primary question concerns associations between FPF biomarkers and continuous OCT variables, while secondary questions connect FPF intensity, FAF area, visual acuity, and participant variables. Correlation analysis is one way to examine whether such measurements vary together in a study sample.

The method description also highlights two common issues in imaging research. First, the record says the data were not normally distributed and explains the choice of Spearman’s rank coefficient. In general, a rank-based association measure can be appropriate when the focus is on ordered relationships and normal-distribution assumptions are not suitable. Second, the record recognizes that measurements from two eyes of the same person may be correlated and describes patient-level bootstrap resampling for p-values. This acknowledges that the participant, rather than each eye treated in isolation, can be important to the structure of the data.

The study also illustrates why methods and results need to be read together. The registry describes an intended analysis approach, but the numerical correlation results and their 95% confidence intervals are not reported in the registry record. Without those estimates, readers cannot judge the direction, magnitude, or precision of the associations. The listed 7 outcome measures and 12 analyses make it important to know how primary questions were distinguished and whether multiplicity was addressed; that information is not reported in the registry record.

Finally, the single-group design is suited to studying imaging associations but does not provide a randomized treatment contrast. The research question is therefore distinct from whether a therapy is effective. The record’s statistical importance lies in its focus on how multiple retinal imaging measures may relate, and in the need to interpret those relationships with attention to clustering, distributional characteristics, uncertainty, and the breadth of analyses.

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 does not report numerical results for the primary or secondary outcomes. Without correlation estimates, 95% confidence intervals, and p-values, the observed direction, magnitude, and precision of the associations cannot be assessed. This is the main limitation for interpreting the findings described in the record.

The study is a single-group investigation with allocation listed as not applicable and masking listed as none. It has no randomized comparator, so it cannot support a between-group treatment-effect interpretation. The record describes cross-sectional associations and does not report a longitudinal analysis that would establish whether FPF measurements predict later disease or symptoms.

The enrolled population is reported as 32 participants, but the number of eyes contributing to each analysis is not reported in the registry record. Eligibility criteria and participant characteristics are also not reported. This makes it difficult to understand the analytic sample and the range of people to whom any association might apply. While the methods description recognizes possible correlation between eyes from the same participant and notes patient-level bootstrap resampling for p-values, the detailed resampling procedure and eye-level analysis counts are not reported.

The record lists 7 outcome measures and 12 analyses but does not report whether multiplicity was addressed, how analyses were prioritized, or whether all planned analyses were posted. Missing-data handling and analysis populations are not reported. It is also unclear from the record how each primary correlation was paired with specific imaging variables, and numerical confidence interval bounds are absent.

The registry does not report a study-specific sample-size justification, detailed imaging acquisition or quality-control procedures, or the full statistical analysis plan. These missing details limit appraisal of measurement reliability, precision, and the potential effects of analysis choices. The study’s completed status does not resolve these reporting limitations.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Retinal Fundus Flavoprotein Fluorescence in Age Related Macular Degeneration — NCT06381596.
• Registry record last updated 2026-07-29; status last verified 2026-07.
• Results first posted 2026-07-29.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry record describes a completed, single-group study of retinal fundus flavoprotein fluorescence in geographic atrophy and age-related macular degeneration. Enrollment was 32 participants. The study began on 2024-04-16 and reached primary completion on 2025-05-27. Participants underwent FPF imaging using the OcuMet Beacon system; masking is recorded as none, and allocation as not applicable.

The primary outcome concerns correlations between FPF intensity and heterogeneity and continuous OCT variables, with an outcome timeframe of up to 45 minutes. The record says Spearman’s rank coefficient was chosen because the sample had relatively few eyes and the data were not normally distributed, and it describes patient-level bootstrap resampling for p-values to account for correlation between eyes from the same participant. It lists 7 outcome measures and 12 analyses.

Numerical outcome results, confidence interval bounds, p-values, multiplicity handling, missing-data methods, and outcome-specific analysis populations are not reported in the registry record. The listed safety counts are 0 serious adverse events, 0 other adverse events, and 0 deaths among 32 participants at risk.