Post-Market Evaluation of the EVO ICL: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Post-Market Evaluation of the EVO ICL (NCT05538754), a na na study. The primary outcome is Elevated Intraocular Pressure (IOP) in Primary Eyes ≥ 30 mmHg.

2. Clinical Question

The study also lists elevated pressure thresholds for fellow eyes as secondary outcomes: at or above 30 mmHg and at or above 40 mmHg. These are distinct outcome definitions, and the registry record does not report their results. It also does not report the primary outcome count. The clinical question is therefore clear as a planned measurement, but its answer cannot be read from the posted results. The study can describe observations within the treated group if results are posted; without a comparator, it cannot isolate an effect attributable to the device from other explanations for an observed pressure measurement.

3. Trial Design

The registry describes the Post-Market Evaluation of the EVO ICL as a completed, single-group study sponsored by Staar Surgical Company. The listed enrollment is 205. The study start date is 2022-09-23, and the primary completion date is 2023-09-21. The record lists the study phase and allocation as not applicable, and masking as none. These entries describe the registered design; they do not establish what analyses were ultimately conducted.

All participants were in the EVO ICL intervention group. The device is described as an implantable collamer lens intended for correction or reduction of myopia or myopia with astigmatism. There is no separate control group in the registered design. In particular, the word “primary” in the endpoint refers to the first-implanted eye, not to a primary treatment arm. Fellow-eye outcomes are separately listed as secondary measures.

The main endpoint counts primary eyes with elevated intraocular pressure at or above 30 mmHg during the 1-6 hours after surgery. The method of measurement is applanation tonometry. The secondary outcomes concern elevated pressure in fellow eyes at or above 30 mmHg and at or above 40 mmHg. The registry lists 12 outcome measures, but the outcomes beyond those named in the record are not described in the available information.

A completed status indicates that the study is registered as completed; it does not itself indicate that results were posted or that the primary analysis was performed. The record lists no analyses. It does not report a protocol, a statistical analysis plan, a rationale for the enrollment target, interim analyses, or details of the analysis population. The clinical study design should therefore be distinguished from the planning assumptions attached to the sample-size illustrations: those assumptions describe a hypothetical two-arm calculation and do not turn this single-group evaluation into a controlled comparison.

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

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: Baseline data were collected on the whole participant level

6. Primary Endpoint

The registry lists the primary outcome as Elevated Intraocular Pressure (IOP) in Primary Eyes ≥ 30 mmHg, measured over 1-6 hours postoperatively.

The primary endpoint is a count: the number of primary eyes with intraocular pressure at or above 30 mmHg in the 1-6 hours after surgery. “Primary eye” is defined in the registry as the first-implanted eye. The threshold and time window make the endpoint a specific measure of early postoperative pressure rather than a general measure of later eye pressure or of all possible pressure changes.

Applanation tonometry is the stated measurement method. It assesses pressure inside the eye by flattening part of the cornea. The endpoint therefore depends on a defined threshold being met on this measurement during the specified postoperative period. The registry describes the count in eyes, not a continuous average pressure value. It does not report how repeated measurements, if any, were handled or how missing pressure measurements were treated.

A threshold count is useful for describing how often measurements cross a prespecified clinical cutoff in the observed group. It is not equivalent to reporting the distribution of all pressure values: measurements below the threshold do not contribute to the count, and the endpoint alone does not describe how far a measurement lies above or below it. The registry record does not report the observed count, the denominator used for the primary endpoint, or an estimate of the rate. No conclusion about the frequency of the endpoint can be drawn from the endpoint definition alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods should be interpreted in light of the design and the kind of outcome measured. This evaluation is registered as a single-group study, and its primary outcome is a count of eyes meeting a threshold. No primary outcome analysis is reported. The registry record does not identify a model, estimation method, confidence interval procedure, or hypothesis test for that endpoint. The explanations below describe general statistical concepts rather than methods confirmed to have been used in this study.

What does a count endpoint represent?

A count endpoint records how many units meet a defined condition. Here, the unit is an eye, and the condition is intraocular pressure at or above 30 mmHg during 1-6 hours postoperatively. To interpret a count as a rate or proportion, a relevant denominator is also needed. The endpoint description does not state the denominator for the primary analysis, and the registry does not report the count. The safety risk set of 408 eyes belongs to the safety information and should not automatically be taken as the primary endpoint denominator.

Counting threshold events discards some detail about the measured values. Two groups could have the same number crossing a threshold while having different distributions of measurements below or above it. Conversely, the count can be easy to interpret when the question is specifically about crossing a defined cutoff. General statistical practice is to report the event count together with its denominator and an uncertainty interval, while explaining the measurement window and how missing observations were handled.

Why can a confidence interval matter?

In general, a confidence interval gives a range of estimates compatible with the observed data under the method used. It communicates precision, not a guarantee that the true value lies within that particular interval. When event counts are small, estimates of proportions can be imprecise, and the choice of interval method may affect its limits. No confidence interval or primary event count is reported in the registry record, so precision for this endpoint cannot be evaluated.

A p-value, if reported, would address how compatible the data are with a specified null hypothesis under its assumptions. It would not by itself quantify the size or clinical importance of an effect. No primary endpoint p-value or hypothesis test is reported. More importantly, the single-group design does not supply a randomized control contrast for testing a between-group treatment effect.

What is over-dispersion, and is it relevant?

In general, over-dispersion occurs when count data vary more than expected under a statistical model such as a simple Poisson model. It can make standard errors too small if the model assumes less variability than the data contain. Alternative models or robust uncertainty estimates may be considered when suitable, but selecting a method requires the actual data and a justified analysis plan. The registry does not report a count model or the data needed to judge over-dispersion. It would be inappropriate to infer that over-dispersion was assessed or that any particular model was used.

There may also be dependence among observations when more than one eye from a participant contributes to an analysis. In general, treating correlated observations as independent can understate uncertainty. The endpoint distinguishes primary eyes from fellow eyes, but the registry record does not describe the analytic handling of eye-level dependence or identify the number of eyes contributing to each endpoint. No assumption about independence can therefore be confirmed from the record.

How should the planning assumptions be read?

The registry’s sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They state that the effect to detect is a specified fraction of the observed effect. These are hypothetical calculation assumptions, not a description of the registered single-group design. Because the record does not post the primary endpoint result or the calculation outputs, the numerical planning implications cannot be assessed.

Such illustrations are not observed power. They describe what sample sizes might be associated with assumed effects under the stated calculation conditions; they do not establish the probability that this completed study detected an effect, and they are not a justification for the actual enrollment unless the protocol says so. The registry record does not report the study’s own sample-size justification. No planning illustration can replace the missing observed outcome or an analysis suited to the actual study design.

The record does not say whether the primary endpoint was analyzed as a count, a proportion, or by another method. It also does not state whether estimates were adjusted for any covariates. Without an analysis plan and posted results, statistical terminology should be used cautiously: the endpoint definition is known, but the inferential method and its output are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures, including the primary pressure endpoint and secondary fellow-eye thresholds. Considering multiple outcomes creates a multiplicity question: when many estimates or tests are examined, the chance of at least one apparently unusual result can increase. In general, a statistical plan can specify which outcomes are primary, how secondary outcomes will be interpreted, and whether any adjustment or hierarchy will be used. The registry record does not report such a plan or any multiplicity adjustment. With no analyses listed, it is not possible to determine whether testing was performed or how multiple outcomes were handled.

The record also does not report missing-data counts or methods. For the primary endpoint, this leaves unanswered how many primary eyes had a pressure measurement in the specified 1-6 hours window, whether any measurement was unavailable, and how unavailable measurements were treated. The same information is not reported for fellow-eye outcomes. General practice is to state the analyzed denominator for each outcome and describe the handling of missing observations, because the denominator affects interpretation of a count or proportion.

Analysis populations are not described. The enrollment is 205, but the registry does not say how many participants or eyes were included in each outcome analysis, or whether any participants were excluded from an analysis. The safety group reports 408 eyes at risk, but that figure does not establish the analysis population for the primary endpoint. The registry record also does not report whether analyses followed an intention-to-treat, per-protocol, or other population definition. These details matter for understanding which observations contribute to each estimate and how broadly the results might apply.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: incorrect evo icl implantation (0.2%), intraocular lens exchange (0.2%), intraocular cilium (0.2%), surgery to remove intraocular cilium (0.2%).

The registry’s all-treated-eyes safety group lists 408 eyes at risk. It reports 2 eyes affected by serious adverse events, 45 affected by other adverse events, and 0 deaths. These are the recorded safety counts; the record does not provide event narratives or additional detail about timing and duration. The figures should be read as safety summaries, not as results for the primary intraocular pressure endpoint.

The serious-event terms listed include Incorrect EVO ICL Implantation, Intraocular Lens Exchange, Intraocular Cilium, and Surgery to Remove Intraocular Cilium. Each term is listed with a percentage of 0.2%. The record does not explain whether terms can refer to overlapping events or provide enough detail to determine how they relate to the count of 2 serious-event cases. The listed percentages therefore should not be added or treated as separate participant counts.

Serious adverse events and other adverse events are distinct categories in the record. Their counts do not indicate whether an event was caused by the device, and the available information does not establish causality. No deaths are listed in the safety group. These entries describe the reported safety record but do not provide a comparison against another group.

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

The study addresses a defined post-market question: how many first-implanted eyes had pressure at or above 30 mmHg in the 1-6 hours after implantation. It also registers fellow-eye pressure thresholds as secondary outcomes. These definitions specify what the study intended to measure, but they do not reveal the observed outcome. The primary count and secondary outcome results are not reported in the registry record.

Accordingly, the available record does not establish how frequent early pressure elevations were in the study group, how precise any estimate might be, or whether the measured values differed from a comparator. The absence of a posted primary result is not evidence that no events occurred. Similarly, the completed status does not mean the outcome was reported or that an analysis was conducted; the record lists no analyses.

The design places a further boundary on interpretation. As a single-group evaluation without a separate control group, the study cannot provide a randomized comparison with another device or with no implantation. If descriptive outcome results were available, they could characterize observations in the evaluated group. They could not alone determine what would have happened in a comparable group under a different treatment or without the device.

The safety entries provide counts for the all-treated-eyes group, including serious and other adverse events and deaths. They do not give a full account of event circumstances, establish causation, or resolve how the listed serious-event terms relate to each other. Taken together, the record supports understanding the registered question, the design, and the limited safety summary. It does not support a conclusion about the primary endpoint’s observed frequency, comparative effect, or precision.

13. Why This Trial Matters Statistically

This study is statistically notable because it asks a narrowly timed, threshold-based question in a post-market device evaluation. The primary outcome focuses on pressure in the early postoperative period, measured by a named method and defined by a specific cutoff. Such precision in the outcome definition helps clarify what an eventual event count would mean and distinguishes it from a continuous pressure summary or a later measurement.

The design also highlights the difference between describing an outcome and estimating a comparative effect. A single-group study can document observations among treated eyes, but without a control group it does not provide a randomized contrast. Readers should not interpret a within-group event count as though it answered a controlled efficacy question. This distinction remains important even when the study is registered as completed.

The registry record illustrates why outcome definitions and outcome results are separate pieces of evidence. It lists the primary and secondary outcomes, but no analyses and no primary outcome result. Without counts, denominators, or uncertainty estimates, the frequency and precision of the endpoint cannot be assessed. A clearly defined endpoint is valuable, but it cannot substitute for reported data.

Finally, the safety summary and the primary endpoint answer different questions. The record reports safety counts among 408 eyes at risk, but those figures do not fill the gap in the early pressure result. Keeping study design, outcome definition, analysis, and safety reporting distinct is essential for a statistically careful reading of post-market evidence.

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 most important trial-specific limitation in the registry record is the absence of the primary endpoint result. The outcome is defined, but its event count, denominator, and uncertainty are not reported. Results for the listed fellow-eye pressure thresholds are also not reported. The record lists 12 outcome measures and no analyses, leaving the reader unable to assess the main endpoint or other registered measures.

The study is registered as single-group, with allocation listed as not applicable and masking as none. There is no separate comparator. Any descriptive findings, if available elsewhere, would therefore lack a randomized control contrast within this registered study. The record does not describe other design features that might clarify how measurement or observation was standardized.

Enrollment is listed as 205, whereas the safety group lists 408 eyes at risk. The registry does not explain the relationship between these figures or identify the denominator used for each outcome. It also does not report the analysis population, missing observations, or rules for handling unavailable measurements. These omissions limit interpretation of both outcome counts and safety summaries.

The record does not report a protocol, a statistical analysis plan, sample-size justification for the actual study, interim analyses, adjustment methods, or a method for addressing multiple outcomes. The planning assumptions describe a two-arm calculation, which differs from the registered single-group design; no numerical planning results are included in the information available. These gaps prevent assessment of whether the analysis followed a prespecified plan or whether the planning illustration is relevant to the completed study.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Post-Market Evaluation of the EVO ICL — NCT05538754.
• Registry record last updated 2026-03-05; status last verified 2026-03.
• Results first posted 2024-12-03.
• 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

NCT05538754 is a completed, single-group post-market evaluation of the EVO ICL sponsored by Staar Surgical Company. The registry lists enrollment of 205, a study start date of 2022-09-23, and a primary completion date of 2023-09-21. Masking is listed as none, and allocation and phase are listed as not applicable.

The primary outcome is the count of primary eyes with pressure at or above 30 mmHg 1-6 hours postoperatively, assessed using applanation tonometry. Fellow-eye thresholds at or above 30 mmHg and at or above 40 mmHg are listed as secondary outcomes. The primary and secondary results are not reported in the registry record, which lists 12 outcome measures and no analyses.

The safety group lists 408 eyes at risk, 2 serious adverse events, 45 other adverse events, and 0 deaths. The record does not report a comparator, analysis population, missing-data approach, or statistical analysis plan.