A Clinical Study to Evaluate The Safety and Effectiveness of The RxSight Light Adjustable Lens (LAL) In Subjects Desiring an Extended Depth of Focus: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Clinical Study to Evaluate The Safety and Effectiveness of The RxSight Light Adjustable Lens (LAL) In Subjects Desiring an Extended Depth of Focus (NCT04177771), a randomized phase not stated study. The primary outcome is Monocular Depth of Focus (DOF) Measured at the logMAR 0.2 Level Compared Between LAL Treatment Group and Control Group.

2. Clinical Question

3. Trial Design

The registry describes a prospective, randomized, controlled, multicenter study with a parallel design and single masking. Its purpose was to evaluate the safety and effectiveness of the RxSight Light Adjustable Lens in subjects desiring an extended depth of focus. The brief summary emphasizes bilateral implantation with the LAL followed by light treatments intended for refractive and presbyopia correction. The listed device interventions also include the Tecnis ZCB00 or ZTC150 IOL and the SofPort LI61AO IOL.

The recorded enrollment was 34. The study start date was 2019-11-15, and the primary completion date was 2021-12-20. The current registry status is TERMINATED. A reason for termination is not reported in the registry record, so the status alone does not explain whether termination was related to recruitment, operations, safety, results, or another consideration.

The outcome record presents results for the LAL Pre-COVID Population, the Tecnis group, the LAL Modified Safety Population, and the SofPort group. The posted group sizes are 10, 7, 7, and 10, respectively. The registry does not explain how the Pre-COVID and Modified Safety populations relate to one another or how those labels correspond to the randomized allocation. Arm descriptions are also incomplete: the LAL and SofPort descriptions are blank in the record.

Although the study is described as randomized and controlled, the record’s control designation points to the LAL Pre-COVID group. That does not align straightforwardly with the primary outcome title’s language about an LAL treatment group compared with a control group. The record does not report enough detail to resolve the intended primary contrast. The planned sample size, allocation ratio, randomization procedure, masking details, and reason for choosing the listed populations are not reported in the registry record.

4. Participant Flow and Accounting

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

Pre-COVID Population

Modified Safety Population

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: Due to the COVID-19 pandemic, study visits for the first 17 subjects enrolled (Light adjustable lens (LAL) and Light Delivery Device (LDD) - Pre-COVID population and Tecnis ZCB00 or ZTC150 IOL) may have been delayed outside protocol specified windows or missed completely. Per the protocol, these subjects will be excluded from the Full Analysis Set populations.

6. Primary Endpoint

The registry lists the primary outcome as Monocular Depth of Focus (DOF) Measured at the logMAR 0.2 Level Compared Between LAL Treatment Group and Control Group, measured over Postop Month 6.

The primary endpoint is monocular depth of focus (DOF), measured at the logMAR 0.2 level and reported in diopters at Postop Month 6. The registry describes measuring monocular distance visual acuity across different spherical lens powers placed over the eye. For each group mean, the lens diopter value corresponding to 0.20 logMAR visual acuity was determined by interpolation. The endpoint was defined as the absolute difference between that negative lens diopter value and 0 diopter.

In general, a depth-of-focus measure describes the range of lens powers over which a specified level of visual acuity is maintained. Expressing the endpoint at a defined acuity threshold makes the target level explicit, while expressing it in diopters connects the result to optical lens power. The endpoint description refers to group means, but does not provide the underlying acuity measurements, interpolation details, or uncertainty around the estimated threshold.

The posted values are 2.3 diopters for the LAL Pre-COVID Population, 0.97 diopters for the Tecnis group, 1.58 diopters for the LAL Modified Safety Population, and 0.85 diopters for the SofPort group. These are descriptive group results. The record does not provide confidence intervals, standard deviations, or a statistical test for a clearly specified two-group comparison, so the precision of the group values and the uncertainty around any contrast cannot be assessed from the posted endpoint data.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a randomized, single-masked, parallel study. These design labels describe how participants were assigned and how the study was structured, but the registry record does not give the operational details needed to assess how randomization or masking was carried out. The reported outcome is monocular depth of focus, expressed in diopters at a defined visual-acuity threshold at Postop Month 6.

What does the endpoint calculation represent?

As a general concept, interpolation estimates a value between observed measurements. In this study’s endpoint description, visual acuity was measured with different spherical lens powers over the eye, and the lens power corresponding to 0.20 logMAR was determined for each group mean. The endpoint then used the absolute distance between that lens power and 0 diopter. The record does not report the individual measurements, the interpolation procedure in further detail, or how uncertainty from that procedure was handled.

The posted endpoint values are point estimates. A point estimate is a single numerical summary of the observed data, rather than a statement of certainty about the underlying population quantity. General statistical practice often accompanies such estimates with measures of variability or confidence intervals. None is posted for this endpoint. As a result, it is not possible to assess the precision of the values or to construct a supported uncertainty interval from the registry information.

What can a group comparison establish?

In general, a comparison between randomized groups is intended to estimate how an outcome differs under the assigned interventions, subject to the study design and analysis. The registry’s primary outcome title describes an LAL-versus-control comparison, but the control designation identifies the LAL Pre-COVID Population. Results are listed for that population, another LAL population, and two IOL groups. The record does not clarify which pair should be treated as the primary contrast. It also reports no analysis results for the endpoint.

A difference between two posted point estimates would be a simple numerical contrast, but such a calculation would not supply the uncertainty around that contrast or resolve which pair was intended. No such recalculation is needed to interpret the record: its own results are group-specific, and the record states that values are missing or not estimable for a two-arm comparison. The listed estimates therefore should not be presented as an inferential treatment effect.

Why are uncertainty measures important?

In general, standard deviations describe spread among observations, while standard errors describe uncertainty in an estimated statistic under a specified analysis. A confidence interval combines an estimate with an uncertainty range and helps show which values remain compatible with the data and method. These concepts are especially important when a study has relatively small group sizes, because point estimates can be sensitive to the observations included. The registry gives group sizes but does not post the endpoint’s spread or standard error. Without those quantities or a model-based analysis, the degree of sampling uncertainty cannot be evaluated.

General hypothesis tests also depend on a defined comparison, an analysis method, and assumptions about the data. The endpoint is labeled NUMBER and the registry’s result kind is count other, while the measurement unit is diopters and the endpoint description refers to group means. The record does not explain this classification, state a statistical model, or post a test statistic or p-value. The statistical analysis plan is not reported in the registry record.

How should planning calculations be understood?

In general, sample-size planning asks how many participants would be needed under chosen assumptions to detect a specified effect with a selected significance level and power. The registry describes a planning approach using a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects expressed as fractions of the observed effect. These are planning assumptions, not evidence that the study was designed using them. The registry does not report its own sample-size justification, and no planning results are included in the endpoint record.

Any sample-size illustration based on an observed effect is conditional on that effect estimate and the assumptions used. Such an illustration is not observed power and does not show the probability that the completed study detected a true effect. In general, observed power is not a substitute for reporting an estimate with its uncertainty. No planning calculation can repair the absence of a clearly specified contrast, dispersion information, and reported inferential analysis.

The outcome record lists no analyses. Therefore, there is no sponsor analysis to compare with a simple recalculation from summary statistics, and no recalculated contrast should be treated as a sponsor result. In general, if a sponsor’s analysis and an unadjusted recalculation disagree, the sponsor’s analysis takes precedence for describing what the trial reported. Here, the central limitation is that the registry does not post an inferential comparison at all.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures and no posted secondary outcome results. It records no analysis results for the primary endpoint. A statistical analysis plan, including any planned hierarchy of outcomes or approach to multiple testing, is not reported in the registry record. It is therefore not possible to determine whether multiplicity was addressed in a prespecified way or whether any outcome comparisons were designated as confirmatory.

In general, multiplicity arises when several outcomes, time points, groups, or analyses are tested. Repeated testing can increase the chance of a chance-positive result unless the analysis plan accounts for it. The existence of several listed outcome measures does not establish that they were all tested, nor does the record indicate which results were intended to support the primary objective. No multiplicity adjustment or testing strategy is posted.

The record does not report how missing endpoint measurements were handled, how many participants lacked a measurement, or whether any imputation was used. It also does not define the primary analysis population or state whether the outcome analysis followed randomized assignment. The labels Pre-COVID Population and Modified Safety Population are present, but their membership rules and relationship to the randomized groups are not explained. These omissions matter because analysis-population choices and missing-data methods can affect which observations contribute to an estimate.

In general, missingness can affect interpretation when the availability of measurements is related to participant characteristics or outcomes. Without counts, reasons, or an analysis strategy, readers cannot assess whether the posted endpoint values represent all randomized participants or a selected subset. The registry’s statement that a two-arm comparison was not estimable further limits interpretation of the intended primary contrast. These are reporting gaps; they do not establish that a particular analysis was or was not conducted outside the registry.

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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: gall bladder removal (14.3%), laparoscopic cholecystectomy for gall stones (14.3%), acute coronary syndrome (10.0%), internal and external hemorrhoids requiring hospitalization (10.0%).

The registry lists safety information for the LAL Pre-COVID Population, the Tecnis group, the LAL Modified Safety Population, and the SofPort group. For each group, the serious-event count affected was 1. The numbers at risk were 10, 7, 7, and 10, respectively. The other-adverse-event counts affected were 9, 2, 4, and 1, respectively. Deaths were recorded as 0 in each group.

These are descriptive counts. The record does not provide confidence intervals, formal between-group safety comparisons, or enough context to determine how events were collected and classified. In general, an affected-participant count is not the same as an event count if a participant can have more than one event. The registry’s safety fields do not explain this distinction or provide additional event-level detail. The group labels also do not clarify how the two LAL populations relate to one another.

The record lists serious terms including “Gall bladder removal” and “Laparoscopic cholecystectomy for gall stones,” each with 14.3%, and “Acute coronary syndrome” and “Internal and external hemorrhoids requiring hospitalization,” each with 10.0%. The record does not specify the denominators or explain whether terms can overlap, so these percentages should be read as registry-reported figures rather than reinterpreted as group-specific risks. Safety counts alone do not establish causation or comparative safety.

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

The posted results show group-level depth-of-focus values at Postop Month 6 for the LAL Pre-COVID Population, the LAL Modified Safety Population, the Tecnis group, and the SofPort group. Those values are 2.3, 1.58, 0.97, and 0.85 diopters, respectively. They are observations reported for the named groups, not a complete inferential analysis of the study’s stated primary question.

The results do not establish the precision of any group value because the registry does not post dispersion measures or confidence intervals. They also do not establish whether a difference between groups is statistically distinguishable from chance variation: no test, p-value, or clearly specified two-group estimate is reported. The control designation and the primary outcome title do not identify a straightforward common contrast. The record also does not explain the population labels or the link between these populations and randomized assignment.

In general, a randomized design can support comparisons when allocation, analysis populations, outcome handling, and the intended contrast are clearly specified. The randomized designation alone does not resolve missing information about the analysis or prove that the posted group summaries are comparable under a particular estimand. The registry record gives no detailed statistical plan, no account of missing outcome data, and no secondary results. It therefore supports a limited descriptive reading rather than a firm conclusion about comparative effect.

The safety record reports serious-event counts, other-adverse-event counts, and deaths by listed group. Those data describe what is recorded, but the registry does not provide inferential safety comparisons or enough detail to assess event overlap and denominators for the serious-term percentages. The TERMINATED status is also part of the study context, but the reason for termination is not reported in the registry record.

These limitations do not imply that the intervention had a particular clinical effect, or that the study’s unposted analyses would necessarily agree or disagree with the descriptive values. They mean that the registry results, as reported, are insufficient to quantify the uncertainty around a treatment contrast or to support a definitive comparative interpretation.

13. Why This Trial Matters Statistically

This trial is statistically notable because its registry combines a randomized, controlled design description with outcome reporting that does not yield a clearly defined primary two-group estimate. The study’s primary outcome title describes an LAL-versus-control comparison, but the control designation points to the LAL Pre-COVID Population. The listed endpoint results include multiple named groups, and the record indicates that a two-arm comparison is missing or not estimable. Readers therefore need to distinguish the study’s design label from the information actually available for interpreting its primary question.

The endpoint is also a derived measure: the record describes identifying the lens power corresponding to 0.20 logMAR through interpolation and expressing depth of focus relative to 0 diopter. Derived outcomes can depend on how measurements are collected and summarized. Here, the registry gives a concise definition but does not report the underlying measurements, uncertainty, or further computational detail. That limits independent assessment of the endpoint’s precision.

Group sizes and point estimates are not enough to establish the reliability of a contrast. The registry does not post variability, confidence intervals, tests, or a detailed analysis plan. Its TERMINATED status and the unexplained labels for the two LAL populations add context that readers may consider, but do not themselves explain the data or the reason the study ended.

More broadly, the record illustrates why interpretation of a clinical trial depends on alignment among the stated question, the control group, the analysis population, and the reported statistical result. When these elements are not clearly connected, descriptive values should remain descriptive. The posted information can identify the measured endpoint and recorded group values, while leaving the uncertainty and comparative interpretation unresolved.

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 explain why the study was terminated. It also does not give a protocol-level account of enrollment targets, randomization procedures, masking procedures, or the planned statistical analysis. These omissions prevent readers from evaluating whether conduct and analysis followed a prespecified plan. A sample-size justification is not reported in the registry record.

The primary endpoint is described in terms of group-mean interpolation, but the registry does not provide individual data, intermediate acuity measurements, dispersion, or confidence intervals. The classification of the endpoint as NUMBER and count other is not reconciled with the description of a diopter-based depth-of-focus measure. No sponsor analysis results are posted, and values are identified as missing or not estimable for a two-arm comparison.

Population definitions are especially unclear. The results distinguish a Pre-COVID LAL Population from a Modified Safety Population, but the record does not state the eligibility rules for either or how participants were assigned to them. The comparator labels include Tecnis and SofPort devices, while the control designation points to an LAL group. This leaves the primary contrast uncertain. The brief summary refers to bilateral implantation and subsequent light treatments, but detailed treatment procedures and adherence information are not reported.

For safety, the record supplies affected counts and selected serious-event terms, but does not explain event definitions, overlap, attribution, or the denominators for the term percentages. Missing endpoint data, reasons for missingness, and handling methods are not reported. These limitations concern the completeness and interpretability of the registry information; they do not establish what additional information may exist outside the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Clinical Study to Evaluate The Safety and Effectiveness of The RxSight Light Adjustable Lens (LAL) In Subjects Desiring an Extended Depth of Focus — NCT04177771.
• Registry record last updated 2025-01-07; status last verified 2024-12.
• Results first posted 2025-01-07.
• 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 describes a prospective, randomized, controlled, multicenter, parallel study with single masking of the RxSight Light Adjustable Lens and Light Delivery Device in subjects seeking extended depth of focus. The listed device groups include LAL, Tecnis ZCB00 or ZTC150 IOL, and SofPort LI61AO IOL. Enrollment was 34. The study began on 2019-11-15, reached primary completion on 2021-12-20, and is marked TERMINATED.

The primary endpoint was monocular depth of focus at the logMAR 0.2 level, measured in diopters at Postop Month 6. Group-specific values are posted, but the registry reports no analysis results, uncertainty measures, or clearly defined two-arm comparison. The meaning of the LAL population labels and control designation is not resolved in the record. Safety counts are descriptive, and the reason for termination, analysis plan, sample-size justification, and missing-data methods are not reported in the registry record.