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 Visual Function With Bilateral AcrySof® ReSTOR® Aspheric SN6AD1 (NCT00710931), a non-randomized phase 4 study. The primary outcome is Binocular Visual Acuity at Distance, Near and Intermediate.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00710931 |
| Phase | Phase 4 |
| Condition | Cataract |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 35 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Alcon Research |
| Results posted | Yes |
2. Clinical Question
Population
People with cataract who underwent phacoemulsification surgery and were studied after bilateral implantation of the AcrySof ReSTOR Aspheric +3.0 intraocular lens. The record lists 35 participants enrolled. Details about eligibility criteria and the characteristics of the participants are not reported in the registry record.
Intervention
Bilateral implantation of the AcrySof ReSTOR Aspheric IOL model SN6AD1, described in the arm as the ReSTOR +3 Multifocal Lens. The study objective was to prospectively evaluate visual parameters after surgery and implantation.
Comparator
There is no separate comparator group. The design is a single-group study, and the allocation is non-randomized. The record does not describe a control treatment or a comparison with another lens.
Primary question
At 6 months after surgery, what were the mean binocular visual acuity measurements at distance, near and intermediate, expressed in LogMAR, and how variable were those measurements? The outcome description includes uncorrected and best corrected visual acuity.
This is a descriptive question about visual acuity in a group receiving the same bilateral lens intervention. It is not a randomized comparison of lenses or treatment strategies. Without a control group, any reported measurements would characterize the study group at the specified follow-up, but could not isolate the effect of the lens from other influences or establish how outcomes would compare under another intervention.
The registry record identifies LogMAR as the measurement scale and states that lower values indicate better visual acuity. It describes distance testing at 4 meters, intermediate testing at 60 centimeters, and near testing at a preferred distance chosen by each participant and recorded in centimeters. However, the actual mean values, standard deviations, and numbers assessed at each distance are not reported in the registry record. Thus, the registered question can be described, but its numerical answer cannot be recovered from the recorded outcome information.
3. Trial Design
The study is listed as a Phase 4, completed, single-group trial with non-randomized allocation and no masking. Alcon Research is the sponsor. The registry lists enrollment of 35 participants, a start date of 2008-10, and primary completion in 2010-09. These dates describe the study record; they do not provide participant-level follow-up or outcome reporting.
The intervention is a device: the AcrySof ReSTOR Aspheric IOL model SN6AD1. The arm description specifies bilateral implantation of the AcrySof ReSTOR +3 Intraocular Lens. The study objective concerns visual parameters after phacoemulsification cataract surgery in participants bilaterally implanted with the lens. The record identifies cataract as the condition.
A single-group design can describe the outcomes measured among participants receiving the intervention, but it does not create a concurrent comparison with another lens, no lens, or another treatment strategy. Non-randomized allocation also means there is no randomized assignment process described. Masking is recorded as none. The registry record does not report further details about how participants were selected, how surgery and follow-up were conducted, or whether outcome assessors were independent of the intervention team.
The registry lists one outcome measure and zero analyses. The primary outcome is binocular visual acuity at distance, near and intermediate, with mean and standard deviation specified as the summary statistics. Although the record gives a follow-up time of 6 months after surgery, it does not report the results for that time point. The statistical analysis plan, sample-size justification, handling of participants who did not complete follow-up, and analysis populations are not reported in the registry record. Consequently, the design and intended measurement can be described, but the record does not support an assessment of outcome magnitude or precision.
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 | ReSTOR +3 Multifocal Lens |
|---|---|
| STARTED | 34 |
| COMPLETED | 29 |
| NOT COMPLETED | 5 |
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 | ReSTOR +3 Multifocal Lens |
|---|---|---|
| Participants analysed | 34 | |
| Age Continuous | years | 74.5 (SD 6.44) |
| Sex: Female, Male: Female | Participants | 18 |
| Sex: Female, Male: Male | Participants | 16 |
6. Primary Endpoint
The registry lists the primary outcome as Binocular Visual Acuity at Distance, Near and Intermediate, measured over 6 months after surgery.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | LogMAR |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is binocular visual acuity at distance, near and intermediate, assessed 6 months after surgery. Visual acuity is recorded in LogMAR, the logarithm of the minimum angle of resolution. The registry description states that a lower LogMAR value indicates better visual acuity. It specifies uncorrected and best corrected acuity, with distance measured at 4 meters, intermediate at 60 centimeters, and near at each participant’s preferred distance, recorded in centimeters.
The endpoint is intended to describe visual performance at different viewing distances after bilateral lens implantation. Measuring more than one distance allows the outcome description to address distance, intermediate, and near vision separately rather than treating visual acuity as a single undifferentiated quantity. Recording both uncorrected and best corrected acuity also distinguishes measurements made without correction from those made under best correction, as described in the registry.
The registry specifies the mean and standard deviation as the summary statistics. In general, the mean describes the average measurement in the assessed group, while the standard deviation describes the spread of individual measurements around that average. These summaries do not, by themselves, show the distribution of individual outcomes or quantify uncertainty about the group mean. The actual means, standard deviations, and numbers assessed are not reported in the registry record, so the endpoint’s observed values and variability cannot be interpreted from this record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the intended primary outcome and its assessment time, but does not report numerical outcome results. No mean LogMAR values, standard deviations, confidence intervals, or numbers contributing data at 6 months are reported in the registry record. Therefore, the direction and size of the observed visual acuity measurements, and the precision with which they were estimated, cannot be assessed from the recorded results.
The description establishes the measurement scale and its direction: lower LogMAR values indicate better visual acuity. That information explains how a reported value would be interpreted, but it does not reveal what values participants actually had. It would be inappropriate to infer a favorable or unfavorable result from the study objective, the intervention name, the follow-up time, or the completion status. Completion of a study does not establish that outcome data were entered into the registry.
The design also defines the scope of any possible interpretation. This is a non-randomized, single-group study with no comparator. If group-level results were available, they could describe the observed measurements in the participants assessed. They would not, on their own, estimate a contrast against another lens or establish what would have happened to the same participants under a different intervention. Other influences on vision and the course of follow-up cannot be separated from the intervention through a single-group description.
The registry lists 35 participants enrolled, but does not report how many had measurements at the primary follow-up or at each testing distance. Enrollment is not interchangeable with the number included in an outcome analysis. Without outcome-specific denominators, it is not possible to assess the extent of missing measurements or whether the analyzed group differs from the enrolled group.
The adverse-event group lists zero participants at risk and zero affected participants for serious and other events; the death count is not reported in the registry record. Because the listed number at risk is zero, those entries do not establish that no events occurred among the study participants. They cannot be interpreted as a complete safety summary for the enrolled group.
Overall, the record supports a description of the study question, design, and measurement procedures, but not a conclusion about the observed primary outcome. Statistical significance, clinical importance, and precision cannot be evaluated without reported estimates and their uncertainty. No treatment-effect comparison is registered for this single-group design.
9. Statistical Methods Explained
The registry describes the primary measure as a continuous outcome summarized by a mean and standard deviation. In general, a continuous measurement can take values along a scale rather than belonging to a set of categories. The mean gives a group-level average, while the standard deviation describes how spread out the measurements are around that average. A mean alone can conceal substantial variation between participants, so the standard deviation provides useful descriptive context. Neither statistic is reported numerically for the primary outcome in the registry record.
LogMAR is the scale used for visual acuity. As the registry explains, lower values indicate better visual acuity. This direction matters when reading an estimate: the meaning of a higher or lower value depends on the scale’s definition. The record describes measurements for uncorrected and best corrected acuity at distance, intermediate, and near. These are distinct measurement conditions and distances, not interchangeable readings of one single observation. The actual endpoint values and the number of measurements available for each condition are not reported in the registry record.
In general, a confidence interval expresses uncertainty around an estimated quantity, such as a mean or a difference between groups. It provides a range of values compatible with the data and the method used to construct the interval. A narrow interval generally indicates greater precision than a wide interval, while neither width nor placement can be understood without the estimate and interval itself. Confidence intervals for the primary outcome are not reported in the registry record. No statistical significance result for that outcome is reported either.
The design is single-group, so the natural descriptive summary would concern measurements within the group receiving bilateral implantation. A comparison between treatments would require a relevant contrast, such as a difference in outcomes between groups, and a method for estimating uncertainty in that contrast. The registry does not identify a comparator group or report a treatment contrast. Any general discussion of comparative methods therefore does not describe an analysis documented for this trial.
For continuous outcomes, standard deviations can be important because measurements may vary more than a simple model assumes. In general, over-dispersion means that the observed variability exceeds what a chosen statistical model expects. If a model fails to account for extra variability, its uncertainty estimates may be too small and conclusions may appear more precise than warranted. This is a general statistical consideration; the registry record does not report a model, an over-dispersion assessment, or an analysis of the visual acuity measurements.
Sample-size planning is also distinct from analysis of observed outcomes. In general, a planning calculation uses assumptions about the effect to be detected, variability, significance level, allocation, and statistical method. A planning illustration based on an observed effect is not evidence that the study had a particular probability of detecting a result, and it is not observed power. The registry record does not report the trial’s sample-size justification or assumptions. Any planning illustration should therefore be read as an illustration under stated assumptions, not as a description of the study’s original design rationale or an observed result.
Power is a design concept concerning the chance that a planned analysis will detect a specified effect under its assumptions. It is not a property that can be inferred from whether a result is statistically significant, and it does not measure the reliability of a particular observed estimate. No power calculation or sample-size justification is reported in the registry record. A planning sample size cannot replace the actual number analyzed, and enrollment of 35 does not establish how many participants contributed to the primary endpoint.
Analysis populations specify which participants are included in a particular analysis. For example, a protocol might define an analysis population based on treatment received, eligibility, or availability of outcome measurements. Such definitions can affect interpretation, especially when participants have incomplete follow-up or deviations from the intended intervention. The registry record does not report analysis-population definitions or the number of participants analyzed for the primary endpoint. It is therefore not possible to determine whether the recorded enrollment and the population measured at 6 months were the same.
Missing data can affect both the effective amount of information and the interpretation of group summaries. In general, missingness may be related to observed or unobserved participant characteristics and outcomes. A complete-case summary describes only participants with available measurements; it may not represent everyone enrolled if missingness is consequential. The registry record does not report missing-data methods, reasons for missing measurements, or follow-up completeness. No assumptions about the handling or impact of missing data should be attributed to the trial.
Finally, multiplicity can arise when several outcomes, time points, or comparisons are tested. In general, conducting multiple tests without an appropriate plan can increase the chance of obtaining at least one apparently unusual result by chance. The registered primary outcome includes multiple visual acuity conditions, but the record does not report a multiplicity procedure or a detailed statistical plan. It is not possible to determine how the sponsor intended to handle the relationship among these measurements or whether additional analyses were planned.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome description covers uncorrected and best corrected visual acuity at distance, intermediate, and near. These are multiple measurement conditions within the registered visual acuity outcome. In general, multiple outcomes or tests can raise multiplicity concerns when several hypotheses are assessed. A statistical plan may specify which outcome is primary, how related measures will be interpreted, and whether any adjustment or hierarchical testing strategy will be used. Such details are not reported in the registry record.
The record lists one outcome measure and zero analyses. It does not report analysis results, a full statistical analysis plan, or a procedure for handling multiplicity. The count of outcome measures alone does not establish how many statistical tests were conducted or planned, and no unreported analysis should be inferred. There is no basis in the record to state whether an adjustment was used.
The registry lists enrollment of 35 participants but does not report the number with observed visual acuity data at 6 months or at each distance and correction condition. Reasons for missing data, the amount of incomplete follow-up, and methods for handling missing measurements are not reported in the registry record. Consequently, the degree to which endpoint summaries might represent all enrolled participants cannot be assessed.
Analysis-population definitions are also not reported in the registry record. The record does not explain whether the primary outcome was intended to include all enrolled participants, only those who received the bilateral intervention, or only those with available measurements. These omissions limit assessment of how the outcome population was formed and how missing data could affect the reported result. No conclusion about missingness or multiplicity handling is supported by the registered information.
11. What the Result Does, and Does Not, Mean
The study record establishes that investigators planned to evaluate binocular visual acuity after bilateral implantation of the AcrySof ReSTOR Aspheric +3.0 lens. It specifies the visual acuity scale, the testing distances, uncorrected and best corrected measurements, and assessment at 6 months after surgery. Those details define the intended outcome, but the registry record does not report the measured means or standard deviations.
Accordingly, the record does not show the observed level of visual acuity, the variability among participants, or the precision of an estimate. It does not support a statement that visual acuity improved, worsened, or remained unchanged. The direction of the LogMAR scale is known from the outcome description, but no actual values are available in the record to apply that interpretation.
The study is non-randomized and single-group, without a separate comparator. Even if descriptive measurements were available, a within-group summary would not establish a comparative effect against another lens or treatment. It would also not isolate the contribution of the implanted lens from other influences on visual outcomes. The design and the missing results therefore place clear limits on the conclusions that can be drawn.
The record also does not provide the number of participants assessed at follow-up, an analysis population, or missing-data methods. Enrollment of 35 should not be treated as the number with complete primary outcome data. Safety entries list zero participants at risk and zero affected participants, with the death count not reported in the registry record; these entries do not establish that no adverse events occurred in the study group.
The appropriate interpretation is limited to the registered study question and design. Outcome magnitude, statistical significance, clinical importance, and precision are not reported in the registry record. The available information neither demonstrates nor rules out an effect; it leaves the primary outcome unanswered.
12. Why This Trial Matters Statistically
This study is statistically instructive because it separates a clearly described measurement plan from the evidence needed to interpret an observed result. The registry specifies a continuous endpoint, a scale with a stated direction, several testing distances, corrected and uncorrected conditions, and a follow-up time. These features help define what investigators intended to measure. They do not substitute for outcome estimates, variability, denominators, or uncertainty intervals.
The single-group, non-randomized design also illustrates the difference between describing a group and estimating a comparative effect. A group mean can characterize the observed participants, but without a comparator it cannot quantify a treatment contrast. This distinction is important when interpreting descriptive clinical outcomes: a detailed measurement protocol does not itself create a counterfactual comparison.
Registry completeness matters for statistical appraisal. The entry reports enrollment and design features, yet does not report numerical primary outcome results, analysis-population definitions, missing-data handling, or the statistical analysis plan. Without these elements, readers cannot evaluate the size or precision of the visual acuity measurements, assess whether follow-up data represent the enrolled group, or determine how multiple measurement conditions were handled analytically.
The record also cautions against treating a nominal zero in an adverse-event field as proof of no events when the listed number at risk is zero. Denominators and outcome definitions are essential for interpreting event counts. In the same way, an enrollment total does not establish the number analyzed, and a completed status does not establish that results are reported. These distinctions are broadly useful when reading registry-based clinical evidence.
13. 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.
A central limitation is that the registry record does not report numerical results for the primary endpoint. Although it identifies mean and standard deviation as the intended summaries, neither is listed for the visual acuity measurements. There are no reported confidence intervals or outcome-specific sample sizes with which to assess precision or completeness.
The design is a non-randomized, single-group study without a comparator. It can describe outcomes in the studied group if results are available, but it cannot provide a randomized comparison or isolate a treatment contrast. The record does not report additional design details that would allow a more complete assessment of potential sources of bias.
Enrollment is listed as 35, but the number assessed at 6 months and the number contributing to each visual acuity condition are not reported in the registry record. Eligibility criteria, participant characteristics, reasons for missing measurements, and analysis-population definitions are also not reported. These omissions prevent assessment of follow-up completeness and the applicability of any hypothetical group summary.
The statistical analysis plan, sample-size justification, and multiplicity and missing-data procedures are not reported in the registry record. The adverse-event entries list zero at risk and zero affected participants, while the death count is not reported in the registry record. Those fields do not provide a usable denominator-based safety interpretation. Together, these limits mean the study question is identifiable, but the registered information is insufficient to judge the magnitude, precision, or comparative meaning of the primary outcome.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Visual Function With Bilateral AcrySof® ReSTOR® Aspheric SN6AD1 — NCT00710931.
- Registry record last updated 2011-12-12; status last verified 2011-12.
- Results first posted 2011-11-08.
- 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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17. Record Summary
NCT00710931 is a completed Phase 4, single-group, non-randomized study sponsored by Alcon Research. The registry lists enrollment of 35, a start date of 2008-10, and primary completion in 2010-09. The intervention is bilateral implantation of the AcrySof ReSTOR Aspheric IOL model SN6AD1 after phacoemulsification cataract surgery.
The primary outcome is binocular visual acuity at distance, near, and intermediate, assessed 6 months after surgery and expressed in LogMAR. Mean and standard deviation are specified; lower LogMAR values indicate better visual acuity. The registry record does not report the primary outcome values, analysis results, participant counts at follow-up, or statistical analysis details. It lists no comparator group, and the design does not provide a randomized treatment contrast.