Three Intraocular Lenses Designed to Improve Distance, Intermediate and Near Vision Following Lens Extraction: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Three Intraocular Lenses Designed to Improve Distance, Intermediate and Near Vision Following Lens Extraction (NCT01225952), a randomized phase 4 study. The primary outcome is Monocular Mesopic Contrast Sensitivity Without Glare (1.5, 3 Cycles/Degree).

2. Clinical Question

3. Trial Design

This was a Phase 4, randomized, double-masked, parallel-group clinical evaluation of three intraocular lenses following lens extraction. The registry lists an enrollment of 93 and identifies cataract as the condition. The study is marked completed. Its recorded start was 2010-07 and its primary completion was 2011-06. Bausch & Lomb Incorporated is listed as the sponsor.

The three device groups were Crystalens AO, ReSTOR 3.0, and AMO Tecnis Multifocal. The record describes Crystalens AO as a silicone multi-piece accommodating lens with a modified plate haptic design. ReSTOR 3.0 is described as an aspheric multifocal lens combining an apodized diffractive region and a refractive region. AMO Tecnis Multifocal is described as a foldable hydrophobic acrylic lens and an ultraviolet light-absorbing posterior chamber lens. These descriptions identify the devices under evaluation; they do not establish which design features account for any observed outcome.

Randomization indicates that assignment was intended to use a chance-based process, but the sequence-generation method, concealment procedures, allocation ratio, and group-specific enrollment are not reported in the registry record. The record labels masking as double, but does not identify which roles were masked or describe how masking was maintained. It also does not give a more detailed account of the procedures, eligibility criteria, or follow-up beyond the endpoint timeframe.

The study summary states that contrast sensitivity, high- and low-contrast visual acuity, glare-meter outcomes, and subject satisfaction were among the measures of interest. The registry lists 26 outcome measures, but lists zero analyses. The endpoint results and detailed statistical plan are not reported in the registry record. Consequently, the design and intended clinical measurement can be described, while the actual comparative findings cannot be assessed from this 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.

Before assignment: 186 participant eyes were enrolled in this study 154 participant eyes completed the study. Participants underwent bilateral phacoemulsification and IOL implantation. Participants were randomized to treatment groups prior to surgery.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set

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 Monocular Mesopic Contrast Sensitivity Without Glare (1.5, 3 Cycles/Degree), measured over Postoperative visit 3 (day 30-60).

The primary endpoint is monocular mesopic contrast sensitivity without glare at spatial frequencies of 1.5 and 3 cycles per degree. It is measured in log contrast sensitivity units at postoperative visit 3 (day 30-60), and the population named for this outcome is the Full Analysis Set.

Contrast sensitivity describes the ability to detect differences in contrast in a visual target. In the registry’s description, a participant views a sine-wave grating, and the spatial frequency indicates how closely spaced its gradations are: a smaller frequency corresponds to wider spacing. The measurement is monocular, meaning it concerns a single eye, and mesopic, meaning it is assessed in dim-light conditions. The endpoint is specified without glare, distinguishing it from a measurement that includes a glare condition. The registry states that a higher mean indicates improved contrast sensitivity.

This kind of continuous measure can describe differences in visual performance that are not captured solely by whether a participant can identify a high-contrast target. Its clinical relevance in this study follows from the stated objective of evaluating lenses designed to support vision at different distances after lens extraction. The registry record does not report endpoint values, between-group estimates, or uncertainty, so the size and precision of any observed difference cannot be described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registered primary outcome is continuous: it is expressed as a mean in log contrast sensitivity units. General statistical explanation: a mean summarizes the central level of a measurement across the observations included in an analysis. It does not show how widely individual observations vary. The registry also identifies standard deviation as the measure of dispersion for the primary outcome. In general, a standard deviation describes the spread of individual measurements around the mean; it is not the same as uncertainty in the estimated group mean or in a difference between groups.

The distinction between variation and precision matters when reading a trial comparison. General statistical explanation: the standard deviation describes variability among measurements, whereas a confidence interval around a group difference describes uncertainty in the estimated difference. The registry record provides neither endpoint standard deviations nor means, differences, or confidence intervals. It therefore does not permit assessment of the outcome distribution, the precision of a comparison, or whether the observed data are consistent with a range of plausible effects.

The endpoint’s measurement conditions also define what its mean represents. It is monocular, measured in dim-light conditions, without glare, and at the stated spatial frequencies. It is recorded at postoperative visit 3 (day 30-60). Results from a different visual condition, timepoint, or analysis population would address a different summary question. The registry identifies the primary endpoint and population but does not report results for this endpoint or explain whether other conditions or visits were analyzed in a prespecified way.

What does randomization contribute?

General statistical explanation: random assignment is intended to make the comparison groups comparable, on average, with respect to characteristics that could affect outcomes. This supports interpretation of a between-group contrast, subject to how randomization was implemented, adherence, missing data, and analysis decisions. The record identifies the study as randomized and parallel-group, but the allocation procedure, allocation ratio, and group-specific enrollment are not reported. No claim about the balance of participant characteristics can be made from the registry information.

What does double masking tell the reader?

The registry labels the trial double-masked. General statistical explanation: masking can reduce the influence of treatment knowledge on behavior, outcome assessment, or other trial processes, depending on who is masked and how masking is maintained. The record does not identify the masked roles or describe procedures for preserving masking. The label alone does not establish that every potential source of knowledge or bias was controlled.

What can be inferred from the statistical plan?

The registry record does not report the statistical analysis plan for the primary outcome. It does not specify a model, covariates, a test, handling of repeated observations, or the planned set of comparisons. The record lists zero analyses. This is not evidence about what analyses may have been performed outside the registry; it means that the registry entry does not give analyses to interpret. In the absence of a stated plan, it is not possible to distinguish prespecified analyses from exploratory ones.

Why do distributional assumptions matter?

General statistical explanation: methods for comparing means often rely on assumptions about the sampling distribution of the estimate and, for some procedures, the distribution and variance of observations. If measurements are highly skewed or variability differs substantially across groups, a method designed for other conditions may describe uncertainty poorly. In some count-data settings, over-dispersion means that observed variability exceeds what a chosen model expects; a model that ignores it can understate uncertainty. These are general considerations, not reported characteristics of this trial. No distributional diagnostics, variance assessment, or method for addressing over-dispersion is reported in the registry record.

What do the planning assumptions mean?

The record describes a sample-size planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that the effect to detect is a stated fraction of the observed effect. These are planning assumptions, not observed trial results or evidence of achieved power. The record does not provide the planning figures in the information available for this analysis, nor does it report the trial’s own sample-size justification. The illustration should not be treated as a description of the actual allocation or as proof that the completed study had a particular probability of detecting an effect.

Because there is no reported primary estimate, the sample-size illustration cannot supply a substitute for the trial’s results. General statistical explanation: a planning calculation depends on assumptions about the target effect, variability, allocation, significance threshold, and analysis. When those assumptions differ from the completed study or its actual data, the planning result does not determine the observed estimate or its precision. In particular, sample-size planning is not observed power and does not establish whether a clinical comparison was conclusive.

10. Multiplicity, Missing Data and Analysis Populations

The study includes a primary endpoint and a broad set of additional outcomes. The registry lists 26 outcome measures and zero analyses. The study summary names contrast sensitivity, high- and low-contrast visual acuity, glare-meter outcomes, and subject satisfaction. The secondary-outcome list contains repeated descriptions of binocular mesopic contrast sensitivity at the listed spatial frequencies. The record does not explain the status of the repeated entries or identify which outcomes were included in any completed analysis.

Multiplicity arises when multiple outcomes, timepoints, groups, or comparisons are tested. General statistical explanation: examining many comparisons can increase the chance that at least one appears statistically notable by chance, so a statistical plan may specify a primary comparison or an adjustment strategy. The registry record does not report a multiplicity strategy, the set of planned pairwise comparisons, or whether any adjustment was used. It is not possible to tell whether the primary endpoint was treated as the sole confirmatory test or how secondary results, if analyzed, were interpreted.

The registry identifies the primary analysis population as the Full Analysis Set, but does not describe its definition, size, or handling of participants with incomplete measurements. Missing-data methods, reasons for missing observations, and the number of participants with endpoint data are not reported in the registry record. The record also does not specify whether exclusions, protocol deviations, or treatment discontinuations affected the analysis population. These omissions limit assessment of how representative the analyzed data were of the randomized groups and whether missingness could have influenced estimates.

These are reporting gaps, not evidence that a particular adjustment or missing-data method was or was not used outside the registry. Without a stated analysis plan and reported results, neither the impact of multiplicity nor the robustness of the endpoint analysis can be evaluated.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists three device groups and reports zero serious adverse events affected in each group: Crystalens AO has 53 at risk, ReSTOR 3.0 has 54 at risk, and AMO Tecnis Multifocal has 51 at risk. These are the recorded group counts; they do not establish that no serious events occurred outside the registry’s reporting scope or during unreported periods. The record gives no serious adverse-event terms.

For other adverse events, the record lists 12 affected among 53 at risk in the Crystalens AO group, 5 among 54 at risk in the ReSTOR 3.0 group, and 6 among 51 at risk in the AMO Tecnis Multifocal group. These counts should be read as registry-reported safety figures, not as a comparison adjusted for follow-up, participant characteristics, or exposure. The registry does not describe the event types, severity categories for these other events, collection procedures, or whether the counts represent people with an event or event occurrences.

Death counts are not reported in the registry record. No further safety interpretation is possible from the listed totals alone. They do not provide the timing, duration, or clinical context of events, and they are separate from the unreported primary contrast-sensitivity results.

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

The registry record identifies a clear comparative question: how three FDA-approved intraocular lenses are evaluated on monocular mesopic contrast sensitivity without glare at postoperative visit 3 (day 30-60). It also gives the direction in which the endpoint is interpreted: a higher mean indicates improved contrast sensitivity. The record describes the randomized, double-masked, parallel-group design and identifies the Full Analysis Set as the primary outcome population.

What it does not provide is the observed outcome result. There are no group means, standard deviations, between-group estimates, confidence intervals, or p-values for the primary endpoint in the registry record. Without these, the direction, magnitude, and precision of any comparison cannot be described. The listed enrollment does not answer whether the groups differed, and the study’s completed status does not supply the missing endpoint estimates.

The same distinction applies to the other stated objectives. The record describes visual acuity, glare-meter outcomes, and subject satisfaction as areas of interest, but does not report their findings. The adverse-event counts provide limited safety information, not a measure of contrast-sensitivity performance. They should not be used as a proxy for the primary outcome or as a basis for claims about comparative benefit.

General statistical explanation: a statistically detectable difference and a clinically meaningful difference are distinct questions. A statistical estimate and its uncertainty can help characterize the evidence, while clinical interpretation requires a relevant context for the size of a difference. Neither kind of judgment can be made without endpoint results and appropriate context. The registry does not report a threshold for a clinically important difference.

Accordingly, the record supports description of the study question and design, but not a conclusion about which device had a higher endpoint mean, whether the devices differed, or how precise any such difference was. It also does not establish that the devices are equivalent: absence of a reported comparison is not evidence of equivalence.

13. Why This Trial Matters Statistically

This trial is statistically notable as a three-arm randomized evaluation with a continuous visual-performance endpoint and multiple stated outcome domains. Such a design raises practical questions about how comparisons are defined, how uncertainty is estimated, which outcome is primary, and how secondary outcomes are handled. The registry identifies one primary contrast-sensitivity endpoint, but does not report the analysis plan or the results needed to evaluate those issues.

The endpoint is carefully qualified by measurement conditions: it is monocular, mesopic, without glare, and assessed at specified spatial frequencies at postoperative visit 3 (day 30-60). Those details matter because a mean describes a particular measurement under particular conditions; it should not be generalized automatically to other visual tasks or settings. The study summary also names binocular contrast sensitivity and other outcomes, highlighting that outcome definitions and measurement conditions are not interchangeable.

The record’s lack of endpoint estimates demonstrates an important distinction in clinical-trial interpretation: registration details describe the question and intended design, while results are needed to estimate comparative effects. Enrollment, randomization, and masking do not on their own reveal the observed effect or its precision. Likewise, a stated planning illustration does not replace an outcome analysis or demonstrate observed power.

The safety figures are also a reminder that counts require context. The registry lists groups at risk and affected counts, but does not provide event descriptions, follow-up context, or an explanation of the counting approach. Those figures should be read narrowly and separately from the primary efficacy measure. In statistical terms, the central lesson is to distinguish what the record defines, what it reports numerically, and what remains unavailable for inference.

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 principal limitation for interpreting this trial from the registry record is the absence of primary and secondary outcome results. Although the primary endpoint is defined, no group means, standard deviations, between-group estimates, confidence intervals, or p-values are reported. Comparative effect and precision therefore cannot be assessed.

Important design details are also not reported in the registry record. These include eligibility criteria beyond the study summary’s description of adults at least 40 years of age, the randomization method, allocation concealment, allocation ratio, the identities of masked roles, and group-specific enrollment. The primary outcome names the Full Analysis Set, but its definition and size are not given. The record does not report endpoint-specific numbers analyzed or explain missing observations, exclusions, or protocol deviations.

The statistical plan is not described. The record does not identify the model or test for the primary endpoint, planned comparisons among the three devices, covariate adjustment, multiplicity handling, or sensitivity analyses. It lists 26 outcome measures and zero analyses, while repeated secondary-outcome descriptions leave the structure of the full outcome set unclear. These reporting limitations prevent assessment of how outcome selection and analysis choices may affect interpretation.

Safety reporting is limited to group-level counts. Event terms, timing, collection methods, and death counts are not reported in the registry record. The meaning of the other adverse-event counts is not further explained. These limitations do not show that the study failed to collect additional information; they define what can be evaluated from the registry entry.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Three Intraocular Lenses Designed to Improve Distance, Intermediate and Near Vision Following Lens Extraction — NCT01225952.
• Registry record last updated 2013-01-18; status last verified 2012-12.
• Results first posted 2013-01-18.
• 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

NCT01225952 is a completed Phase 4, randomized, double-masked, parallel-group evaluation sponsored by Bausch & Lomb Incorporated. The registry records enrollment of 93, a start date of 2010-07, and primary completion in 2011-06. The study concerns cataract and compares Crystalens AO, ReSTOR 3.0, and AMO Tecnis Multifocal following lens extraction.

The primary endpoint is monocular mesopic contrast sensitivity without glare at spatial frequencies of 1.5 and 3 cycles per degree, measured at postoperative visit 3 (day 30-60). It is a mean in log contrast sensitivity units in the Full Analysis Set, with higher mean described as indicating improved contrast sensitivity. The registry lists 26 outcome measures and zero analyses, but does not report endpoint results or a detailed statistical plan.

Recorded serious adverse-event counts are zero affected in each group. Other adverse-event counts are listed by group, while event details and death counts are not reported in the registry record. The available information describes the trial’s question and structure but does not permit estimation of comparative outcome effects.