Visual Enhancement Device in Low Vision Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Visual Enhancement Device in Low Vision Patients (NCT03794752), a na na study. The primary outcome is Best Corrected Visual Acuity (BCVA) With the Head-mounted Electronic Visual Enhancement Device.

2. Clinical Question

In practical terms, the study was intended to examine visual acuity while participants used the device and to consider that assessment against glasses-based best corrected acuity. The brief summary also describes near visual acuity and selected questions from the National Eye Institute 25-item visual function questionnaire (NEI VFQ-25). Those assessments provide additional context about vision-related function, but the registry record does not give numerical results for them. The stated study visit was prospective and non-randomized. That design can describe measurements collected under the device condition, but without reported paired measurements or a concurrent comparison group, it does not establish a comparative treatment effect.

3. Trial Design

The registry describes a prospective, non-randomized, single-group study of a head-mounted electronic visual enhancement device. Allocation is listed as NA, masking as NONE, and the study status as TERMINATED. Enrollment is recorded as 8. The study was sponsored by University of Texas Southwestern Medical Center and began in 2015-02; primary completion is recorded as 2018-12-28.

The target population in the brief summary consists of people with low vision diagnosed with age-related macular degeneration or diabetic macular edema and ETDRS visual acuity from 20/60 to 20/400 in both eyes. The registry's condition list includes age-related macular degeneration and diabetic retinopathy. These descriptions are related but not identical; the registry record does not clarify the difference in wording.

The intervention is described as a compact device similar to glasses, powered by a battery pack, with an electronic display positioned over one eye. The brief summary says a coaxial camera and image-enhancing or correction algorithms are used to aid the most degraded eye. The intervention is a device rather than a medication, and the study is not listed as a randomized comparison.

The brief summary describes a single visit lasting about 1.5 hours, including an eye examination. Planned assessments include ETDRS best-corrected distance visual acuity, best-corrected near visual acuity, and tests based on questions 5,6,7 and 11 of the NEI VFQ-25. The primary endpoint is the participant count associated with best corrected visual acuity using the device at 5 minutes post intervention.

The study objective refers to comparing device-assisted vision with best corrected visual acuity with glasses. The record does not provide a separate comparator arm description or outcome results for a glasses condition. A protocol-level objective should therefore be distinguished from an analysis actually documented in the registry. The registry reports 0 analyses, and no numerical primary outcome result is available 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

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: Participants performing skills without the head mounted visual aid device will be provide the baseline values for each aspect of this study.

6. Primary Endpoint

The registry lists the primary outcome as Best Corrected Visual Acuity (BCVA) With the Head-mounted Electronic Visual Enhancement Device, measured over 5 minutes post intervention.

The primary endpoint is titled best corrected visual acuity with the head-mounted electronic visual enhancement device. It is measured with an ETDRS chart, and its listed unit is participants; the parameter is a count of participants. The stated assessment time is 5 minutes post intervention. The registry also describes the study visit as including an ETDRS best-corrected distance visual-acuity assessment.

Visual acuity is a direct measure of the ability to resolve visual detail under a defined assessment condition. In general, measuring acuity with the device can describe performance while the device is being used. A comparison with glasses-based best corrected acuity could be informative if measurements under both conditions and the analysis connecting them were reported. The endpoint description alone does not show the magnitude or direction of any difference.

A participant count is not itself a continuous measure of the degree of visual acuity. It may identify how many participants contributed to an outcome or met a specified criterion, but the registry record does not state a threshold or response definition for this count. The result field is not accompanied by a numerical value, and no distribution of acuity measurements is reported. Thus, the endpoint's title identifies the intended assessment, while the posted record does not permit interpretation of the actual acuity observed.

The broader examination described in the brief summary includes near visual acuity and selected NEI VFQ-25 questions. These may add functional context beyond a chart-based acuity measurement. Numerical results for those assessments are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information in this record is limited. The design is identified as single-group and non-randomized; allocation is NA, masking is NONE, enrollment is 8, and the registry reports 0 analyses. The primary outcome is identified as a participant count, but no numerical outcome result, effect estimate, or inferential statistic is given. The following concepts explain how such information is usually interpreted; they are general statistical explanations, not descriptions of an analysis reported for this trial.

What does a single-group design allow?

A single-group study can describe outcomes observed among participants receiving or using an intervention. If measurements are taken under multiple conditions in the same participants, a paired analysis may describe within-participant changes. That approach requires measurements from both conditions and a stated analysis method. The registry objective refers to device-assisted vision compared with best corrected acuity with glasses, but the record does not provide the paired values or specify a comparison analysis. A single-group label does not, by itself, establish that a particular within-participant comparison was completed.

Random assignment is used in comparative designs to reduce systematic differences between treatment groups, on average. This record is not listed as randomized and does not describe a parallel control group. Therefore, any causal interpretation or between-group treatment-effect estimate would require information not reported in the registry record. The stated objective and the design fields should be read separately: an objective can describe a desired comparison without documenting that comparative data or analysis were reported.

What does the primary outcome measure?

The endpoint is a count of participants associated with best corrected visual acuity using the device, assessed with an ETDRS chart at 5 minutes post intervention. A count is interpretable only with a clear definition of what qualifies for inclusion in that count and the number assessed. The outcome description does not specify a response threshold, and no observed count is posted. Although visual acuity itself can be measured on a scale, the registry lists the endpoint parameter as a count rather than a reported acuity score. These details prevent reconstruction of an outcome estimate from the endpoint title alone.

In general, outcome definitions should identify the measurement, assessment time, population, and any threshold used to classify a participant. If the outcome is a continuous acuity measurement, useful summaries might include a location and measure of variability. If the outcome is a binary classification or count, interpretation depends on the classification rule and the participants assessed. The record does not report the specific outcome values or a threshold, so neither type of summary can be interpreted for this study.

How should uncertainty be read?

General explanation: a confidence interval expresses uncertainty around an estimate under a statistical model and its assumptions. Wider intervals indicate less precision, while narrower intervals indicate greater precision. A small study may yield imprecise estimates, but precision cannot be judged from enrollment alone; it depends on the outcome data and the analysis. No confidence interval is reported for the primary endpoint, and there is no estimate from which to assess precision.

A hypothesis test compares observed data with a null hypothesis using a prespecified method. A p-value is not a measure of the probability that an intervention works, nor does it give the size of an effect. Its interpretation depends on the model, outcome definition, and analysis population. No p-value or test method is reported in the registry record. It would be inappropriate to infer statistical significance or lack of significance from the fact that analyses are listed as 0.

What do the planning assumptions mean?

The record describes a sample-size planning illustration based on an observed effect. Its stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. These are planning assumptions, not a report of the trial's own design or an analysis of the enrolled group. The registry does not report a sample-size justification for the single-group study. The equal-allocation, two-arm assumption does not match the registry's single-group design description, so the illustration should not be read as an account of the actual allocation.

General explanation: a sample-size calculation estimates how much information a future study might need under stated assumptions. It depends on the target effect, outcome variability, error rates, allocation, and analysis method. Planning calculations are not observed power and do not show whether an intervention produced an effect. A calculation based on an observed effect can also inherit uncertainty from that estimate. The record does not give the numerical observed effect used in the illustration or enough information to assess the calculation's suitability for this study.

Over-dispersion is a general concern when count data vary more than a statistical model expects. If present, it can make standard errors too small under an inadequately specified model and make confidence intervals or tests misleading. This endpoint is described as a count, but no outcome distribution or count model is reported. There is therefore no basis to assess whether over-dispersion was relevant or whether any adjustment was made.

10. Multiplicity, Missing Data and Analysis Populations

The brief summary describes several assessments: ETDRS best-corrected distance visual acuity, best-corrected near visual acuity, and tests based on questions 5,6,7 and 11 of the NEI VFQ-25. The registry lists 5 outcome measures, while identifying the device-assisted best corrected visual acuity measure as primary. It reports 0 analyses and provides no numerical outcome results in the record available for interpretation.

When a study examines multiple outcomes or multiple statistical tests, the chance of at least one apparently notable result can increase. General statistical practice may address this through prespecification, hierarchical testing, or adjustment for multiplicity. The registry record does not report a multiplicity strategy, an analysis plan, or which outcomes were analyzed. It is not possible to determine whether any adjustment was planned or needed.

Missing-data methods are also not reported in the registry record. There is no account of missing visual-acuity assessments, incomplete questionnaires, withdrawals, exclusions, or the assumptions used to handle missing observations. Enrollment of 8 should not be interpreted as the number included in each outcome analysis. The primary outcome's analyzed population and denominator are not reported.

The record does not describe an intention-to-treat population, a per-protocol population, or another analysis population. The reasons for termination and their possible effect on data collection are not reported in the registry record. Without outcome-level denominators and missing-data details, the completeness and representativeness of the posted results cannot be evaluated.

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 a group titled “Use of Head Mounted Device.” For that group, 8 participants are recorded as at risk for serious adverse events and 0 as affected; 8 are recorded as at risk for other adverse events and 0 as affected. Deaths are recorded as 0. These are the safety counts reported in the registry.

A zero count means that no event in that category is recorded as having affected a participant in the registry entry. It does not show that risk is absent, and it should not be treated as evidence that an event could not occur. Safety counts are most informative when interpreted alongside the observation period, event definitions, severity criteria, and completeness of reporting. Those details are not reported in the registry record.

The safety figures do not provide event narratives, timing, duration, or information about how events were assessed for a relationship to device use. The registry also does not report a separate comparison group for safety. These counts describe the listed group and should not be used to estimate a comparative safety difference. The record's terminated status does not explain whether or how termination affected safety follow-up.

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

The registry record establishes that a prospective, non-randomized, single-group study was conducted to evaluate a head-mounted visual enhancement device in people with low vision. It identifies the intended population, the device, a primary visual-acuity assessment, and the assessment time of 5 minutes post intervention. It also records enrollment of 8 and gives safety counts for the device-use group.

It does not report the numerical result for the primary visual-acuity endpoint. It gives no acuity scores, participant count for the endpoint, measure of change, confidence interval, p-value, or statistical analysis. The registry therefore does not show the size, precision, or direction of any observed visual-acuity result. No conclusion about the device's performance can be drawn from the outcome information posted in the registry record.

The brief summary's stated comparison with best corrected visual acuity with glasses is not accompanied by a reported comparator result. Because the design is listed as single-group and non-randomized, and no paired measurements or comparative analysis are posted, the record does not support a quantified comparison between device use and glasses. It also does not establish a causal effect.

The recorded zero adverse-event counts describe what is entered in the safety fields. They do not demonstrate absence of risk, particularly without details about observation and reporting. Similarly, the terminated status is a registry status, not an explanation of why the study ended or whether termination changed the results available.

In general, a clinical trial's interpretation depends on its outcome data, analysis methods, completeness of follow-up, and precision as well as its design. Here, the record supplies useful design and registry-status information, but not the numerical outcome evidence needed to judge the study's primary question. That distinction is important: absence of a posted result is not evidence of either benefit or lack of benefit.

13. Why This Trial Matters Statistically

This study is statistically notable because its stated objective invokes a comparison, while the registry classifies the design as single-group, non-randomized, with allocation listed as NA. The distinction matters. A question about outcomes while using a device is descriptive; a question about how those outcomes differ from glasses requires comparable measurements and a specified comparison. The posted record does not include those results.

The endpoint also illustrates why outcome labels and outcome values must be distinguished. The primary endpoint names best corrected visual acuity with the device, identifies an ETDRS chart, and gives a post-intervention assessment time. But its listed parameter is a participant count, and no count or acuity value is reported. A clear measurement description helps define a research question, but it cannot substitute for the observations needed to answer it.

Enrollment of 8 and the record's terminated status make transparency about analysis populations, missing assessments, and follow-up especially relevant. Those details are not reported in the registry record. Their absence prevents readers from assessing whether the posted safety entries and intended visual assessments reflect all enrolled participants or only a subset.

Finally, the sample-size planning description assumes equal allocation between two arms, whereas the registry describes a single-group study. This illustrates why planning calculations should be interpreted in relation to the actual design and not mistaken for evidence about the observed result. The record reports 0 analyses, so the planning assumptions do not supply an estimate of the device's performance. Statistically, the key lesson is that a registry description can define a worthwhile question while leaving the empirical answer unavailable.

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 main limitation for interpretation is the absence of numerical primary outcome results. The registry record identifies a participant-count endpoint for device-assisted visual acuity but gives no outcome count or acuity measurements. No estimate, confidence interval, or test result is reported, and the registry lists 0 analyses. The study's primary question therefore cannot be answered from the posted results.

The intended comparison with glasses is not accompanied by a comparator arm or a reported paired analysis. The study is classified as single-group, non-randomized, and unmasked. The record does not explain whether measurements with glasses were collected, how they were compared with device measurements, or whether assessors knew the assessment condition.

The registry does not report the analysis population, endpoint denominator, outcome completion, missing-data handling, or reasons for study termination. These omissions make it impossible to evaluate completeness or determine whether all enrolled participants contributed to each assessment. The reason for termination is not reported in the registry record.

The population description uses both diabetic macular edema in the brief summary and diabetic retinopathy in the listed conditions; the record does not clarify this difference. The endpoint is listed as a participant count without a stated threshold or response definition, limiting its interpretability even apart from the missing result. Finally, the safety fields provide counts but no event narratives or observation details. Each of these limitations concerns what can be concluded from the registry record; none establishes what the study may have found outside the posted information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Visual Enhancement Device in Low Vision Patients — NCT03794752.
• Registry record last updated 2021-01-05; status last verified 2020-12.
• Results first posted 2021-01-05.
• 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

NCT03794752 is a prospective, non-randomized, single-group study of a head-mounted electronic visual enhancement device for people with low vision associated with age-related macular degeneration or diabetic eye disease. Enrollment is recorded as 8, masking as NONE, and status as TERMINATED. The primary endpoint concerns best corrected visual acuity using the device, assessed with an ETDRS chart at 5 minutes post intervention.

The brief summary describes an examination including distance and near visual acuity and selected NEI VFQ-25 questions. The primary objective refers to comparison with best corrected visual acuity with glasses, but the registry record does not report a comparator result or numerical primary outcome. It lists 0 analyses. Safety fields record 0 serious adverse events, 0 other adverse events, and 0 deaths in the device-use group. The reason for termination, missing-data handling, and analysis populations are not reported in the registry record.