Clinical Investigation of the Next-Generation Intraocular Lens: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Investigation of the Next-Generation Intraocular Lens (NCT03111550), a randomized na study. The primary outcome is Monocular Distance Corrected Near Visual Acuity (DCNVA) at 40 cm.

2. Clinical Question

3. Trial Design

The registry identifies this as a randomized, double-masked, parallel-group clinical investigation. The brief summary describes it as prospective, multicenter, bilateral, and six months in duration. It was conducted at 12 sites in the U.S.A. The listed enrollment is 242, while the summary describes approximately 240 subjects and says they were equally split between the two test groups and the control group. Those descriptions are reported as written; the posted endpoint analysis has its own group counts.

The study began on 2017-05-10, reached primary completion on 2018-02-23, and is listed as completed. The phase field is recorded as NA. Abbott Medical Optics is named as the sponsor. The three device groups were TECNIS ZHR00, TECNIS ZQR00, and TECNIS ZXR00, with ZXR00 serving as the control.

The primary endpoint is a monocular measure. The registry states that the safety population includes all subjects implanted who have available data and that, for monocular endpoints, it consists of first eyes implanted with a study lens. The posted endpoint counts are 76 for ZHR00, 72 for ZQR00, and 78 for ZXR00. These are the analysis counts for this outcome, not a replacement for the registry’s overall enrollment description.

The registry record does not report the method used to generate or conceal the randomization sequence, the exact masking procedures, or the allocation implementation. It also does not report the original sample-size justification or enough detail to reconstruct the full study protocol. The design labels support describing the investigation as randomized, double-masked, and parallel-group, but do not fill in those unreported operational details.

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: A total of 242 subjects were enrolled in this study, and 229 subjects were implanted with study IOL in first eye.

Overall Study

Analysis population for the primary outcome, as defined in the registry: The safety population (SP) of all subjects implanted who have available data will be used for all analysis. For the monocular endpoints, the safety population will consist of first eyes implanted with a study IOL.

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 Distance Corrected Near Visual Acuity (DCNVA) at 40 cm, measured over 1 month postoperative.

The primary endpoint was mean distance-corrected near visual acuity, measured monocularly at a distance of 40 cm, under photopic conditions. It was assessed one month after surgery and recorded in LogMAR. The endpoint description specifies first-eye measurements, and the analysis population is the safety population of implanted subjects with available data.

Visual acuity is a continuous measurement, so the registry reports a mean and standard deviation for each group. In general, a mean describes the group’s average measurement, while the standard deviation describes how spread out individual measurements are around that average. LogMAR is a scale used to record visual acuity; as general measurement context, lower LogMAR values correspond to better acuity. This scale interpretation does not replace the study’s own endpoint definition or establish the clinical importance of a particular difference.

A one-month postoperative measure gives a defined early assessment point for comparing group averages. It does not summarize every outcome over the investigation’s six-month duration. The registry record does not report a threshold for a clinically important difference, nor does the primary endpoint alone answer questions about safety, other visual tasks, or longer-term outcomes.

7. Results Posted in the Registry

• Tecnis ZQR00: mean 0.14 versus 0.14 on control; difference 0.00 (95% CI -0.04 to 0.05), standardized effect d = 0.04; z-test p = 0.823.
• Tecnis ZXR00: mean 0.28 versus 0.14 on control; difference 0.14 (95% CI 0.10 to 0.18), standardized effect d = 1.19; z-test p = <0.001.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous, so the main summaries are means and standard deviations. A mean locates the group average on the measurement scale. A standard deviation describes variability among the measurements; it is not the uncertainty of the mean itself. In general, greater variation among participants makes a group mean less precisely estimated when other features are held constant.

What does a mean difference represent?

A mean difference compares the average in one group with the average in another. For the reported recalculations, the ZQR00 and ZXR00 groups are compared with ZHR00. A value near zero indicates that the two group averages are close on the recorded scale; a positive or negative value gives the direction of the subtraction used for the comparison. The posted differences are unadjusted comparisons based on the reported summary statistics. They are not adjusted for other participant characteristics.

The ZQR00 comparison has a mean difference of 0.005, while the ZXR00 comparison has a mean difference of 0.14. These estimates should be read together with their intervals, not as exact values known without uncertainty. The scale is LogMAR, so the numerical direction is interpreted on that scale. The registry record does not report a clinically important difference threshold that would translate these numerical comparisons into a judgment about practical importance.

What does a confidence interval add?

In general, a confidence interval expresses the uncertainty around an estimated quantity using a range of values compatible with the data and the calculation method. A narrower interval indicates greater precision than a wider interval, but precision is not the same as clinical importance. When an interval for a mean difference includes zero, the data are compatible with no difference as well as with differences in either direction within the interval. When it excludes zero, that is evidence against a zero difference under the calculation used, but does not establish that the difference matters in practice.

The interval for ZQR00 compared with ZHR00 runs from -0.039 to 0.049 and includes zero. The interval for ZXR00 compared with ZHR00 runs from 0.103 to 0.177 and does not include zero. These are unadjusted recalculated intervals. The registry’s own analysis details and any adjusted intervals are not reported in the registry record.

How should the p-values be understood?

A p-value describes how unusual data at least as inconsistent with a null hypothesis would be under a specified statistical model, assuming the null hypothesis and model are appropriate. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. The reported unadjusted p-value is 0.823 for ZQR00 versus ZHR00 and < 0.001 for ZXR00 versus ZHR00. These values correspond to the unadjusted comparisons and should not be treated as multiplicity-adjusted findings.

The registry record does not report the complete statistical analysis plan, the method used for any adjustment, or whether any model-based covariate adjustments were used in the sponsor’s analysis. No claim about those methods can be inferred from the posted means and standard deviations alone.

Why does variability matter?

Standard deviations describe how dispersed individual measurements are within a group. In general, the uncertainty in a mean comparison depends on both the amount of variability and the number of observations contributing to each mean. When outcome variability is greater, a given difference between means is harder to estimate precisely unless the study includes more observations. This is one reason estimates should be read alongside both their group counts and intervals.

For the primary endpoint, the posted counts are 76 for ZHR00, 72 for ZQR00, and 78 for ZXR00. The reported standard deviations are 0.12, 0.149, and 0.116. The recalculated comparisons use pooled standard deviations of 0.135 for ZQR00 versus ZHR00 and 0.118 for ZXR00 versus ZHR00. These summaries do not show whether variability differs across subgroups or changes over time.

What does randomization contribute?

As a general design principle, random allocation is intended to make comparison groups similar on average with respect to measured and unmeasured characteristics. It supports a comparative interpretation when the randomization is implemented as intended and outcome data are handled appropriately. The registry identifies the study as randomized, but the sequence generation, concealment procedures, and details of adherence to allocation are not reported in the registry record.

Double masking is also listed. In general, masking can reduce the influence of expectations on care or assessment, depending on who is masked and how procedures are carried out. The record does not specify which participants, investigators, assessors, or other staff were masked, nor does it describe how masking was maintained. The design labels are relevant context but cannot establish those operational details.

What is not available from these summaries?

The posted statistics do not provide individual participant measurements, the distribution’s shape, baseline values, or a breakdown of missing primary endpoint data. They also do not report a clinical importance threshold or adjusted results for multiple comparisons. Without those details, the group means and unadjusted recalculations support a focused description of the primary endpoint at one timepoint, rather than a full assessment of every statistical question about the investigation.

10. Confidence Intervals and Precision

Precision is conveyed by the confidence interval around each recalculated mean difference. For ZQR00 compared with ZHR00, the estimate is 0.005 and the interval extends from -0.039 to 0.049. Its inclusion of zero means the posted data are compatible with a small difference in either direction as well as with no difference, under the unadjusted calculation. The estimate alone should not be mistaken for a precisely established difference.

For ZXR00 compared with ZHR00, the estimate is 0.14 and the interval extends from 0.103 to 0.177. This interval is entirely above zero, indicating that the recalculated comparison is more precise about the direction of the difference than the ZQR00 comparison. It still represents uncertainty about the difference’s exact size. Statistical precision does not indicate whether the difference crosses a threshold that matters to patients; such a threshold is not reported in the registry record.

In general, a confidence interval is not a range containing a fixed proportion of individual participants’ measurements. It concerns uncertainty in an estimated quantity, here a difference between group means. The posted standard deviations describe participant-level spread, while the intervals describe uncertainty in the comparison. These are different aspects of the results.

The intervals are unadjusted recalculations from posted summary statistics. The registry record does not report intervals from the sponsor’s own analysis or any multiplicity-adjusted intervals. The interpretation should therefore remain tied to these unadjusted comparisons and to the endpoint counts and available-data population described for the study.

11. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are illustrations based on the observed mean difference, not the trial’s original design calculation. For these continuous-outcome comparisons, the figures represent participants per arm, not total events. The assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each planning scenario uses the stated fraction of the observed effect as the effect to detect.

The 80% power column gives the planned number of participants per arm for a hypothetical study designed to have an 80% chance of detecting the specified effect under those assumptions, if that effect is real. The 90% power column gives the corresponding number for a 90% chance. These are prospective planning quantities, not a measure of the probability that the observed result is true.

The rows for 100%, 75%, and 50% of the observed effect ask what the planning requirement would be if a future study aimed to detect the full observed difference or a smaller fraction of it. Smaller effects generally require more participants to distinguish them from random variation under otherwise similar assumptions. The contrast is particularly important when the observed difference is small: reducing the target effect further can lead to very large planning requirements.

These calculations are not observed power. They do not estimate what the completed study’s chance of finding an effect was after the outcome was known. The registry’s original design assumptions and sample-size justification are not reported in the registry record, so the planning illustrations should not be taken as a reconstruction of the trial’s design process.

12. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 0.005; pooled standard deviation σ = 0.135.
2. n = 2 × (1.96 + 0.842)² × 0.135² / 0.005² = 11,424.0, rounded up to 11,424 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 0.00499999999999998                      # observed difference in means
sigma <- 0.13488379067294                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(3111550)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 11,424 (80% power), 15,294 (90% power)
 75% of observed effect: n per arm = 20,310 (80% power), 27,189 (90% power)
 50% of observed effect: n per arm = 45,696 (80% power), 61,174 (90% power)
power.t.test: 11424.9 
Simulated power at n = 11,424 per arm: 0.800 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

13. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures and five analyses. It identifies the primary endpoint, but a complete statistical analysis plan, including how multiple outcomes or comparisons were handled, is not reported in the registry record. The comparisons described for the primary endpoint are unadjusted recalculations. No multiplicity-adjusted p-values or confidence intervals are reported in the registry entries, so the stated p-values should not be interpreted as adjusted for the number of analyses.

Multiplicity matters in general because conducting multiple statistical tests creates more opportunities for apparently unusual results even when there are no true differences. A prespecified testing strategy can define which results are confirmatory and how error rates are controlled. Without the registry’s full strategy, it is not possible to determine whether the two pairwise comparisons were part of a broader testing hierarchy or whether any adjustment was applied in the sponsor’s analysis.

The primary endpoint population is described as the safety population of implanted subjects with available data. For monocular endpoints, that population consists of first eyes implanted with a study lens. The endpoint counts are 76 for ZHR00, 72 for ZQR00, and 78 for ZXR00. The registry does not report the number of randomized participants with missing endpoint data, reasons for missingness, or analyses assessing the effect of missing data.

In general, an available-data analysis can be affected if the chance of having a measurement is related to the outcome or to group assignment. The record does not provide enough information to judge whether that issue arose or how it was addressed. It also does not report whether the primary endpoint analysis included adjustments for baseline measures or other covariates. The stated population definition is therefore useful context, but it does not supply all details needed to evaluate missing-data handling or analysis populations across every outcome.

The safety counts are reported for group-specific risk populations, while the primary endpoint uses its stated available-data safety population. The record does not explain every difference between those populations or provide a participant flow account in the registry record described. These limitations constrain interpretation of both the comparative results and the completeness of outcome reporting.

14. 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: retinal tear and repair (1.4%), secondary surgical intervention: iol removal (1.4%), lung cancer (1.4%), chronic obstructive pulmonary disease (1.4%), retinal detachment (1.4%).

The registry reports serious adverse event counts alongside the number at risk in each group. For Tecnis ZHR00, the serious adverse event figures are 8 affected among 78 at risk. For ZQR00, they are 7 among 73 at risk. For ZXR00, they are 5 among 79 at risk. These are group-level counts as reported; they do not establish that the events were caused by a device.

The record separately lists other adverse event counts: 4 among 78 at risk for ZHR00, 3 among 73 at risk for ZQR00, and 3 among 79 at risk for ZXR00. Deaths are listed as 2 for ZHR00, 0 for ZQR00, and 1 for ZXR00. The record does not provide enough detail to infer causes, timing, relatedness, or whether individual events overlap across categories.

The listed serious-event terms include retinal tear and repair, secondary surgical intervention for IOL removal, lung cancer, chronic obstructive pulmonary disease, retinal detachment, and lens removal due to undesired optical phenomena due to fixed pupil; each is reported as 1.4%. These entries describe reported terms, not a complete narrative of each event. The registry record does not report enough detail to determine comparative safety from these counts alone.

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

The primary result describes average monocular distance-corrected near visual acuity at 40 cm, one month after surgery, for the three lens groups. The posted means were 0.136 for ZHR00, 0.141 for ZQR00, and 0.276 for ZXR00 on the LogMAR scale. The unadjusted recalculated comparison between ZQR00 and ZHR00 was close to zero, with an interval that includes zero. The comparison between ZXR00 and ZHR00 was positive, with an interval above zero.

Those results answer a narrow statistical question about group averages at a particular assessment time. They do not establish whether an observed difference is clinically important, because the registry does not report a meaningful-difference threshold. They also do not establish how individuals experienced their outcomes: group means and standard deviations do not reveal every participant’s measurement or the shape of the outcome distribution.

The results do not answer whether one device is preferable for a particular person, and they should not be used as medical advice. They do not summarize all visual outcomes, all safety outcomes, or the entire six-month investigation. The record lists other outcome measures, but secondary results are not posted in the described details. The primary endpoint should not be treated as a substitute for those outcomes.

The unadjusted p-values and confidence intervals describe statistical evidence and precision under the recalculation used. They do not state the probability that a device works, nor do they prove that a group difference is important or unimportant. Interpretation is also limited by unreported details about missing data, multiplicity, the original analysis plan, and the clinical importance threshold.

Overall, the posted information supports a focused comparison of the one-month group means and their unadjusted uncertainty. Broader conclusions require information not reported in the registry record, including the full analysis plan, further outcome results, and context for judging the clinical meaning of differences.

16. Why This Trial Matters Statistically

This investigation illustrates how a continuous clinical endpoint can be compared across multiple randomized groups. Reporting group means, standard deviations, analysis counts, mean differences, and confidence intervals makes it possible to distinguish the estimated size of a comparison from its uncertainty. The contrast between the ZQR00 and ZHR00 comparison and the ZXR00 and ZHR00 comparison also shows why a point estimate should not be interpreted without its interval.

It is statistically important that the endpoint be tied to its measurement conditions and analysis population. The record defines a monocular, first-eye, photopic measure at 40 cm and one month postoperative, and specifies available data in the safety population. That definition helps readers understand what the group summaries represent and what they do not represent.

The record also highlights the importance of transparent reporting beyond a p-value. The original sample-size rationale, full multiplicity plan, details of missing endpoint data, and threshold for clinical importance are not reported in the registry record. Without those details, readers can describe the posted statistical comparison but cannot fully assess its relationship to the planned analysis or practical significance.

Finally, the planning illustrations use the observed effect to show how sample-size requirements change with the target effect under stated assumptions. They are distinct from the trial’s original design calculation and from observed power. Keeping those concepts separate helps prevent retrospective planning figures from being mistaken for evidence about the quality or success of the completed study.

17. 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 report the original sample-size justification, the statistical analysis plan, or the procedures used to generate and conceal the randomization sequence. Although randomization and double masking are listed, the record does not specify who was masked or how masking was maintained. These missing design details limit independent assessment of implementation.

For the primary endpoint, the stated analysis includes implanted subjects with available data. The number and reasons for missing one-month measurements, the handling of missingness, and sensitivity analyses are not reported in the registry record. The record also does not provide baseline endpoint values or adjusted comparisons, so the posted results are limited to the available unadjusted summaries and recalculations.

The registry lists three outcome measures and five analyses, but it does not report the full multiplicity strategy or adjusted primary comparisons. It also gives no threshold for a clinically important LogMAR difference. Therefore, statistical evidence can be described, but its clinical importance and its place within the full set of planned analyses cannot be established from the posted information.

The primary endpoint is one measurement at one postoperative timepoint, whereas the investigation is described as six months. Secondary results are not posted in the described record. The adverse-event listings do not provide event narratives, timing, relatedness, or enough detail to compare safety comprehensively. These limitations mean the endpoint results should be interpreted as a focused account of the posted one-month group averages rather than a complete evaluation of every outcome in the investigation.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Clinical Investigation of the Next-Generation Intraocular Lens — NCT03111550.
• Registry record last updated 2025-06-24; status last verified 2025-06.
• Results first posted 2020-08-24.
• 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.

21. Record Summary

The completed registry record describes a randomized, double-masked, parallel-group, prospective, multicenter, bilateral investigation of TECNIS ZHR00 and ZQR00 against TECNIS Symfony ZXR00. It lists enrollment of 242 and describes a six-month study conducted at 12 U.S. sites.

The primary endpoint was mean photopic monocular distance-corrected near visual acuity at 40 cm, one month postoperative, measured in LogMAR. Posted group means were 0.136 for ZHR00, 0.141 for ZQR00, and 0.276 for ZXR00. The unadjusted recalculated mean difference was 0.005 for ZQR00 compared with ZHR00 and 0.14 for ZXR00 compared with ZHR00.

The registry record does not report the original sample-size justification, full multiplicity and missing-data plans, or a threshold for clinical importance. The results therefore describe the posted endpoint summaries and their unadjusted precision, with those limitations in mind.