Clinical Evaluation of the One-Piece Tecnis Multifocal Intraocular Lens (IOL): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Evaluation of the One-Piece Tecnis Multifocal Intraocular Lens (IOL) (NCT01210807), a non-randomized phase 4 study. The primary outcome is Mean LogMAR Binocular Photopic Distance Corrected Near Visual Acuity at 33 cm.

2. Clinical Question

The study description frames the evaluation around near vision with the multifocal lens compared with the monofocal lens, alongside general postoperative outcomes for the multifocal lens. That stated aim should be distinguished from what the registry results quantify: the primary endpoint is identified, and Snellen equivalents are stated, but the underlying group estimates and their uncertainty are not reported in the registry record.

Because allocation was non-randomized, group membership was not assigned by randomization according to the registry. Differences between groups could therefore reflect factors other than lens type. The record does not describe how participants came to receive each lens or whether any adjustment was planned to address group differences. Consequently, the comparison is descriptive rather than a randomized causal contrast.

3. Trial Design

This was a phase 4, non-randomized, single-masked, parallel-group clinical evaluation of two intraocular lenses for participants with cataract. One group received the ZMB00 multifocal lens and the other received the ZCB00 monofocal lens. The registry lists Abbott Medical Optics as sponsor and reports the study as completed.

The record reports enrollment of 70 subjects: 36 in the ZMB00 group and 34 in the ZCB00 group. For the primary endpoint, it states that one assessment was performed per participant within the 4-6 month timeframe. Endpoint data at the 4-6 month visit were available for 33 ZMB00 participants and 31 ZCB00 participants. The reason endpoint data were unavailable for the other enrolled participants is not reported in the registry record.

Non-randomized allocation is important to interpretation. Random assignment is one way to balance measured and unmeasured participant characteristics across groups, on average. That protection does not follow from a non-randomized design. The registry explicitly cautions that the arms are not a like-for-like control comparison. It does not report the allocation process, baseline comparability, or an adjusted analysis addressing potential differences between groups.

The record says masking was single, but which people were masked is not reported in the registry record. It describes a parallel model, in which participants are assigned to one group rather than both lenses being assessed as sequential treatments. The specific procedures for masking, lens assignment, postoperative assessment, and follow-up are not reported in the registry record.

Although endpoint timing and participant counts are stated, the statistical analysis plan, sample-size justification, and any planned interim analyses are not reported in the registry record. The posted results list no analyses. Thus, the design features that can be described are limited to the recorded allocation, masking, parallel structure, enrollment, endpoint, and visit window; additional design or analysis details should not be inferred.

4. Participant Flow and Accounting

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

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Within the 4-6 month time frame, one assessment was performed per participant. Though 70 subjects started the study (36 ZMB00; 34 ZCB00), data for logMAR binocular photopic distance corrected near visual acuity at 33 were available for only 33 ZMB00 and 31 ZCB00 subjects at the the 4-6 month visit.

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: A total of 34 ZMB00 multifocal and 33 ZCB00 monofocal subjects were implanted bilaterally. Data analysis for baseline characteristics was completed on these 67 subjects.

6. Primary Endpoint

The registry lists the primary outcome as Mean LogMAR Binocular Photopic Distance Corrected Near Visual Acuity at 33 cm, measured over 4-6 Months.

The primary endpoint is mean logMAR binocular photopic distance-corrected near visual acuity at 33 cm, assessed at 4-6 months. It describes near vision measured with both eyes under photopic, or lighted, conditions, with distance correction. The endpoint is continuous: each participant’s acuity measurement contributes to a group mean, and the registry identifies standard deviation as the intended measure of spread.

LogMAR is a scale for expressing visual acuity. In general, it supports quantitative comparisons and statistical summaries of acuity measurements. A group mean describes the average on that scale, while a standard deviation describes how dispersed participants’ measurements are around that average. The record also gives Snellen equivalents: 20/24 for the multifocal group and 20/81 for the monofocal group. These are stated as equivalents for the group means, not as the numerical logMAR means themselves.

Near acuity at a specified distance is relevant to the study’s stated focus on near vision. However, a single mean does not describe every participant’s experience or the full distribution of measurements. Interpretation also depends on the variability, uncertainty around the group estimates, and comparability of the groups. The numerical logMAR means, standard deviations, confidence intervals, and inferential comparison are not reported in the registry record, limiting how precisely the endpoint contrast can be assessed from the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a continuous primary outcome summarized as a mean with standard deviation. It does not report the numerical group means, standard deviations, confidence intervals, or a statistical test for that outcome. The concepts below explain how such summaries and analyses are generally interpreted; they do not establish which unreported methods were used in this trial.

What does a mean describe?

For a continuous outcome, a mean is the arithmetic average of the measurements in a group. It can provide a compact description of the group’s central value, but it does not reveal the full pattern of individual results. Participants can have measurements near the mean or much farther from it. The standard deviation describes the degree of spread around the mean: a larger standard deviation indicates more variability among measurements, while a smaller one indicates measurements are more concentrated. The standard deviation is not the same as the uncertainty in the estimated mean.

In this evaluation, the endpoint is mean logMAR binocular photopic distance-corrected near visual acuity at 33 cm. The registry says the intended dispersion summary is standard deviation and provides Snellen equivalents of 20/24 and 20/81 for the respective group means. The numerical logMAR means and standard deviations are not reported in the registry record, so readers cannot use the posted results to assess within-group spread or reconstruct the group estimates.

How should uncertainty be understood?

A confidence interval is a range of values that expresses uncertainty around an estimate under the assumptions of the statistical method used. A narrow interval generally indicates greater precision than a wide interval. For a between-group comparison, an interval for the difference would help show which effect sizes are compatible with the data and model. It would not, by itself, resolve bias from non-randomized allocation or other limitations in study conduct.

No confidence interval for the primary endpoint is reported in the registry record. Nor is a p-value or test statistic reported. A p-value, when used, summarizes how unusual data at least as incompatible with a specified null hypothesis would be under the test’s assumptions. It is not a measure of clinical importance, the probability that a treatment works, or the probability that the null hypothesis is true. Since no such result is recorded, statistical significance cannot be determined from the primary endpoint entry.

Why does allocation matter for a group comparison?

In a randomized comparison, chance assignment can help balance participant characteristics across treatment groups. With non-randomized allocation, the groups may differ in characteristics that are related to the outcome. Those differences can make it difficult to separate an intervention effect from other explanations for the observed comparison. Statistical adjustment can sometimes account for measured characteristics, but it cannot automatically remove bias from unmeasured or poorly measured factors. The registry classifies allocation as non-randomized and cautions that the arms are not a like-for-like control comparison. An adjusted model or adjustment plan is not reported in the registry record.

The record also says masking was single. Masking can reduce the influence of expectations on some aspects of treatment or outcome assessment, depending on who is masked and how procedures are carried out. Which parties were masked and how masking was maintained are not reported in the registry record. Masking does not substitute for random allocation, and the available information does not establish how much risk of bias it addressed.

What do the endpoint counts mean?

The registry reports 36 participants in the multifocal group and 34 in the monofocal group, with primary-endpoint data available for 33 and 31 participants, respectively, at the 4-6 month visit. It states one assessment per participant within that timeframe. These counts clarify how many participants contributed endpoint data, but do not explain why some measurements were unavailable or what analysis population was used. Missing-data methods can matter because an analysis limited to participants with observed measurements may be biased if the missingness is related to outcomes or participant characteristics. The missingness mechanism and handling method are not reported in the registry record.

How should the planning illustrations be read?

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 arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. Such planning estimates are conditional on their assumptions and are not observed power. They do not establish the trial’s original sample-size justification or show that the study was designed around those assumptions. The trial’s own sample-size justification is not reported in the registry record. Any planning figures should be interpreted as illustrations rather than as trial results or evidence about the precision of the observed comparison.

More broadly, statistical methods can summarize measurement variability and quantify uncertainty, but they cannot correct every design limitation. A complete interpretation would require the numerical endpoint estimates, uncertainty measures, analysis specification, handling of missing data, and adequate information about comparability of groups. Several of these details are not reported in the registry record, so the posted results permit a limited descriptive reading rather than a complete inferential assessment.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("ZMB00 Multifocal Intraocular Lens", "ZCB00 Monofocal Intraocular Lens")
n   <- c(33, 31)
m   <- c(0.07, 0.61)
sp  <- c(0.12, 0.15)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  ZMB00 Multifocal Intraocular Lens  33  0.070  0.120  0.027  0.113
CARM  ZCB00 Monofocal Intraocular Lens  31  0.610  0.150  0.555  0.665

11. Multiplicity, Missing Data and Analysis Populations

The primary endpoint is specified as mean logMAR binocular photopic distance-corrected near visual acuity at 33 cm, assessed at 4-6 months. The registry also lists a secondary outcome: the number of subjects with 20/40 or better best-corrected binocular distance visual acuity. It reports two outcome measures and zero analyses. The results do not include a numerical analysis of the primary endpoint or a reported analysis of the secondary outcome.

Multiplicity arises when a study evaluates multiple outcomes, timepoints, treatment contrasts, or statistical tests. If many hypotheses are tested, the chance of at least one apparently notable result can increase unless the analysis plan addresses that issue. This is a general statistical concern, not evidence that a particular multiplicity adjustment was or was not used in this study. A prespecified testing hierarchy, adjustment method, or explanation of how primary and secondary outcomes were interpreted is not reported in the registry record.

For the primary endpoint, data were available for 33 ZMB00 participants and 31 ZCB00 participants at the 4-6 month visit, compared with group enrollment of 36 and 34. The reason for missing endpoint data is not reported in the registry record. Neither the missing-data mechanism nor the method used to handle missing measurements is reported. The record says one assessment per participant was performed within the endpoint timeframe, but it does not explain whether any other assessment or analysis population was used.

Analysis populations can include all assigned or enrolled participants, those receiving the intervention, or participants with evaluable measurements, depending on the study and its plan. The record does not identify an analysis population beyond reporting the available endpoint counts. It also does not report whether the posted group descriptions reflect an intention-to-treat, per-protocol, or other analysis. These omissions limit assessment of selection from missing data and consistency with any planned analysis.

12. 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 2% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists serious adverse events affecting zero participants in the ZMB00 multifocal group, among 36 at risk, and zero participants in the ZCB00 monofocal group, among 34 at risk. These are participant counts in the posted serious-adverse-event entries. They should be read as recorded counts, not as proof that no serious events occurred outside the registry’s reporting or that the risks are identical.

The record separately lists 3 other adverse events among 36 participants at risk in the multifocal group and 4 among 34 at risk in the monofocal group. The categories are listed separately from serious adverse events; no additional details about the nature, severity, timing, or relationship of these other events are reported in the registry record. No statistical comparison of safety outcomes is reported.

Specific serious adverse-event terms are not listed. Death counts are not reported in the registry record. Small group sizes and the absence of detailed event descriptions limit what can be concluded from these counts. In particular, the registry entries do not provide a complete account of event rates over time or a basis for comparing safety between the non-randomized groups.

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

The results can be read as a record of a non-randomized comparison of the ZMB00 multifocal and ZCB00 monofocal intraocular lenses, with mean near visual acuity at 33 cm specified as the primary endpoint at 4-6 months. The registry gives Snellen equivalents of 20/24 and 20/81 for the two group means and reports endpoint data for 33 and 31 participants, respectively. It also records zero participants with serious adverse events in each group and lists 3 and 4 other adverse events.

Those entries do not provide a complete statistical comparison. The numerical logMAR means, standard deviations, confidence intervals, and primary-endpoint test result are not reported in the registry record. Without those quantities, the magnitude and precision of the difference cannot be evaluated from the posted results. The Snellen equivalents alone do not describe variability among participants or uncertainty in the group estimates.

The comparison also does not establish a causal effect. Allocation was non-randomized, and the registry explicitly says that the arms are not a like-for-like control comparison. Potential differences between groups may influence outcome comparisons. The record does not describe an adjustment strategy that would allow readers to assess whether such differences were addressed.

The available data should not be interpreted as demonstrating that either lens works or does not work. They describe the recorded outcome and safety entries, with substantial limits on statistical interpretation. Missing endpoint data, unknown handling of those data, unspecified analysis populations, and absent inferential results further constrain conclusions. The record does not report enough detail to determine whether the observed group summaries represent all enrolled participants or to quantify how compatible the results are with a range of possible effects.

Accordingly, the most defensible reading is descriptive: the registry documents the study design, enrollment, endpoint definition, Snellen equivalents, available endpoint counts, and adverse-event counts. It does not document the information needed for a precise or adjusted estimate of the treatment contrast.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of why an endpoint label and group counts are not enough to evaluate a clinical comparison. The record defines a continuous near-vision outcome, identifies its assessment window, and reports how many participants had data available. Yet the actual logMAR means and standard deviations are not reported in the registry record. Without those estimates, readers cannot assess the observed spread or quantify the primary comparison from the posted results.

Its non-randomized allocation also matters. A direct comparison between groups can be affected by differences in participant characteristics or care, and the registry cautions that the arms are not a like-for-like control comparison. This illustrates why study design and statistical analysis need to be considered together: a numerical contrast, even if reported, would not automatically be a causal estimate.

The discrepancy between enrolled and endpoint-available participants highlights another general issue. Group counts tell readers how many observations contributed at the stated visit, but not why data were unavailable or how missingness was handled. Missing-data assumptions can affect both the estimate and its uncertainty, particularly if the chance of having an observed result is related to participant characteristics or outcomes.

The record also distinguishes a planning illustration from the study’s own design. Planning assumptions based on an observed effect should not be mistaken for an original sample-size justification or observed power. Since the trial’s own justification and detailed analysis plan are not reported, those matters cannot be evaluated from the registry record.

15. 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 primary statistical limitation is incomplete reporting of the outcome results. Although the endpoint is defined and the record gives Snellen equivalents for its group means, the numerical logMAR means and standard deviations are not reported in the registry record. No confidence interval, p-value, or other inferential result is listed. As a result, the primary comparison’s magnitude and precision cannot be assessed fully.

The non-randomized allocation limits comparability between groups. The registry cautions that the groups are not a like-for-like control comparison, but does not report the allocation process, baseline characteristics, or an adjusted analysis. The record therefore does not allow readers to determine whether important group differences were present or addressed.

Endpoint data were available for 33 participants in the ZMB00 group and 31 in the ZCB00 group, while the enrolled group counts were 36 and 34. The reasons for missing endpoint observations and the method used to address them are not reported in the registry record. The analysis population is also not specified. These gaps prevent assessment of potential bias from incomplete data.

Other important details are absent: the statistical analysis plan, sample-size justification, any interim analyses, multiplicity handling, and the identity of the party or parties masked. The record lists a secondary outcome but does not report an analysis for it. Safety descriptions are limited to participant counts; specific serious adverse-event terms and death counts are not reported in the registry record. These limitations restrict both the interpretation of the primary outcome and the breadth of conclusions that can be drawn from the posted results.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Clinical Evaluation of the One-Piece Tecnis Multifocal Intraocular Lens (IOL) — NCT01210807.
• Registry record last updated 2025-02-04; status last verified 2025-01.
• Results first posted 2013-12-13.
• 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.

19. Record Summary

The registry describes a completed phase 4, non-randomized, single-masked, parallel-group evaluation of the One-Piece Tecnis Multifocal intraocular lens, model ZMB00, and the One-Piece Tecnis monofocal intraocular lens, model ZCB00, in participants with cataract. Enrollment was 70: 36 in the multifocal group and 34 in the monofocal group.

The primary endpoint was mean logMAR binocular photopic distance-corrected near visual acuity at 33 cm, assessed at 4-6 months. The record gives Snellen equivalents of 20/24 and 20/81 for the group means and reports endpoint data for 33 and 31 participants, respectively. The numerical logMAR means, standard deviations, and inferential analysis are not reported in the registry record.

The record lists zero participants with serious adverse events in each group, with 3 and 4 other adverse events. It cautions that non-randomized arms are not a like-for-like control comparison. The analysis plan, missing-data handling, and sample-size justification are not reported in the registry record.