This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Accuracy of the New Barrett TAL Formula With the Argos Measurements: A Multicenter Prospective Study (NCT06085131), a registered phase not stated study. The primary outcome is The Percentage of Eyes That Achieve a Postoperative Manifest Spherical Equivalent Refraction ≤ ±0.50 D..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT06085131 |
| Phase | Phase not stated |
| Condition | Cataract |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 523 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Shammas Eye Medical Center |
| Results posted | Yes |
2. Clinical Question
Population
The record concerns subjects undergoing cataract surgery, with 523 participants enrolled. The study description says subjects were assessed before surgery, during surgery, and 5-8 weeks afterward. The number of eyes contributing to the primary endpoint, and the relationship between enrolled participants and analyzed eyes, are not reported in the registry record.
Intervention
Preoperative biometry was performed with the Argos device. The study is described as examining refractive accuracy with Argos using the Barrett TAL formula after successful cataract surgery. The record does not provide further procedural details about how the formula was applied or how surgical decisions were made.
Comparator
No concurrent comparator group is described. The listed group is Argos Biometer, and the record characterizes the study as observational rather than randomized. There is therefore no like-for-like control comparison in the registry record from which to isolate the contribution of the device or formula.
Primary question
The primary endpoint asks what percentage of eyes achieved a postoperative manifest spherical equivalent refraction within ±0.50 D at 2 months postoperative. This is a threshold-based measure of refractive accuracy. The endpoint definition is reported, but its observed percentage and the statistical analysis are not reported in the registry record.
3. Trial Design
This is a prospective, multicenter, multi-surgeon, observational study concerning refractive accuracy after cataract surgery. It lists Argos as the device intervention and describes preoperative biometry with the Argos device. The study summary says that subjects would be assessed preoperatively, operatively, and at 5-8 weeks postoperatively; assessments would include visual acuity, manifest refraction, and preoperative biometry. These details describe the intended assessment schedule and measurements, not the completeness of the data ultimately collected.
The registry lists enrollment of 523 and a completed status. The recorded study start is 2023-10-31, and the primary completion date is 2025-01-29. The primary endpoint has a timeframe of 2 months postoperative. The record does not explain the relationship between that endpoint timeframe and the 5-8 week postoperative assessment window in the summary.
The study is not a randomized comparison, and the registry does not describe a control arm. The listed Argos Biometer group is not a comparative control group. Consequently, the design can describe outcomes observed among participants assessed in this setting, but the record does not support a controlled contrast between Argos and another device, formula, or care strategy. Whether other factors were considered in the investigators’ analyses is not reported in the registry record.
The record lists four outcome measures and zero analyses. It does not report outcome values, the number of eyes included in each outcome, or details of participant flow. Sample-size justification, eligibility criteria, allocation procedures, and a prespecified statistical analysis plan are not reported in the registry record. The study’s completed status therefore should not be mistaken for a complete account of its analyzed data or findings.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Argos Biometer |
|---|---|
| STARTED | 523 |
| COMPLETED | 523 |
| NOT COMPLETED | 0 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Argos Biometer |
|---|---|---|
| Participants analysed | 523 | |
| Age, Continuous | years | 71.6 (SD 7.23) |
| Sex: Female, Male: Female | Participants | 316 |
| Sex: Female, Male: Male | Participants | 207 |
| Race and Ethnicity Not Collected | Participants | — |
6. Primary Endpoint
The registry lists the primary outcome as The Percentage of Eyes That Achieve a Postoperative Manifest Spherical Equivalent Refraction ≤ ±0.50 D., measured over 2 months postoperative.
| Element | Registry entry |
|---|---|
| Result type | Count Of Units |
| Measure of spread | not applicable |
| Unit | Eyes |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the percentage of eyes with a postoperative manifest spherical equivalent refraction within ±0.50 D, assessed at 2 months postoperative. Manifest refraction is a clinical measurement of refractive error. Spherical equivalent combines the refractive components into a single value; the endpoint then classifies whether that value falls within the stated tolerance around the target. The unit is eyes, rather than participants.
A threshold endpoint expresses how often observed outcomes meet a specified accuracy criterion. It can be easier to interpret as a proportion than a continuous average, but it also reduces a range of measurements to two categories: within the criterion or outside it. Eyes just inside and just outside the threshold are counted differently even when their measurements are close. The endpoint does not, by itself, describe the distribution of all refractive errors or the size of errors outside the threshold.
The registry also lists secondary outcomes concerning the percentages of eyes within other stated refractive thresholds, mean absolute prediction error, and mean absolute prediction error in axial-length subgroups. The actual estimates for the primary and secondary outcomes are not reported in the registry record. The record also does not specify the denominator used for the primary percentage, how multiple eyes from one participant were handled, or how missing measurements were treated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry defines a clinically interpretable accuracy endpoint, but it does not post the endpoint’s observed value. The percentage of eyes meeting the ±0.50 D threshold at 2 months postoperative, its denominator, and any interval expressing its precision are not reported in the registry record. Without those quantities, the central result cannot be described or judged for precision from this record.
The study is prospective and includes multiple sites and surgeons, which describes how the investigation was organized. Those features do not make it a randomized comparison. The registry lists one Argos Biometer group and identifies the study as observational. As a result, any reported refractive outcome would describe outcomes in the studied setting; it would not, without a suitable comparison and analysis, establish that the device or formula caused those outcomes or performed better than an alternative.
The listed enrollment is 523, but that does not establish how many eyes contributed to the primary endpoint. The endpoint is measured in eyes, while enrollment is stated as participants. The number of analyzed eyes, exclusions, unavailable refractions, and handling of participants contributing more than one eye are not reported in the registry record. Those details matter because the denominator and the dependence between measurements affect the interpretation and precision of a percentage.
The status is completed, but the record lists zero analyses and does not post outcome estimates. Completion refers to study status in the registry; it is not a substitute for outcome reporting. Nor can the endpoint’s result be inferred from the intended assessment schedule, the enrollment count, or the listed secondary outcomes.
The registry also records zero serious adverse events and zero other adverse events in the Argos Biometer group, among 523 at risk in each category, and zero deaths. These are registry figures for the recorded categories. They do not establish that no event of any kind occurred, and the record does not provide event definitions, collection procedures, or a detailed safety analysis.
Any planning illustrations based on an observed effect should be understood as hypothetical calculations under stated assumptions, not as trial outcomes or observed power. The observed effect itself is not reported in the registry record, so the registry content available for interpretation does not support a numerical efficacy conclusion.
9. Statistical Methods Explained
Statistical methods help turn measurements into estimates while making their uncertainty and limitations visible. In this study, the primary endpoint is a proportion: the number of eyes meeting a specified refractive threshold relative to the relevant number of eyes assessed. The registry defines the threshold and timeframe, but does not report the numerator, denominator, estimate, or uncertainty interval. The points below explain how such results are generally interpreted and identify details that are not reported in the registry record.
What does a percentage endpoint represent?
For a threshold endpoint, each eligible measurement is classified according to whether it satisfies the stated criterion. The resulting percentage summarizes the share meeting that criterion in the analyzed group. It does not show how far measurements that miss the threshold fall from it, and it does not preserve the full shape of the measurement distribution. A continuous measure such as mean absolute prediction error can complement a threshold percentage by describing the magnitude of prediction errors, although a mean can also obscure variation among observations.
Here the endpoint is expressed in eyes, while enrollment is expressed in participants. The registry does not report how many eyes were analyzed or whether participants could contribute more than one eye to the endpoint. If multiple eyes from one participant are included, their measurements may be correlated rather than statistically independent. General statistical practice accounts for such clustering when estimating uncertainty; whether and how it was handled in this study is not reported in the registry record.
How should uncertainty be read?
A confidence interval is a general statistical way to express the precision of an estimate. For a proportion, it gives a range of values compatible with the observed data under the method’s assumptions. A narrower interval generally indicates greater precision, while a wider interval indicates less precision. An interval is not a guarantee that the true value lies within its endpoints, and it does not resolve biases caused by study design or missing data. No confidence interval for the primary endpoint is reported in the registry record.
A p-value, when used, describes how compatible data are with a specified statistical model or null hypothesis. It does not measure the size or clinical importance of an effect, and it does not give the probability that a hypothesis is true. The registry record lists zero analyses and does not report a p-value or a hypothesis test for the primary endpoint. It would therefore be inappropriate to infer statistical significance from the record.
What is the role of a comparison?
Comparative inference ordinarily depends on comparing groups whose outcomes can be meaningfully contrasted. This record describes a prospective observational study and lists an Argos Biometer group, without a concurrent control group. The registry also explicitly notes that the arms are not a like-for-like control comparison. A single-group estimate can describe outcomes in the observed cohort, but it cannot by itself separate the influence of the device and formula from other features of care, participant characteristics, or clinical setting.
Observational data can be affected by confounding: factors related both to the care or measurement approach and to the outcome can influence an apparent association. This is a general concern, not a claim that a particular factor distorted this study. Adjustment methods can address measured factors under their assumptions, but cannot automatically remove unmeasured confounding. Whether the investigators used adjustment or other methods is not reported in the registry record.
What do the secondary measures add?
The listed secondary outcomes include other threshold proportions, mean absolute prediction error, and mean absolute prediction error for short, long, and medium axial-length categories. These outcomes address different aspects of refractive accuracy. Threshold proportions show the share meeting a chosen tolerance, whereas mean absolute prediction error summarizes the average magnitude of prediction error without indicating its direction. Subgroup estimates can describe whether accuracy varies across the specified axial-length categories, but they may be less precise than an overall estimate, especially when subgroup counts are limited. Subgroup counts and results are not reported in the registry record.
For mean measures, variability is important alongside the average. A standard deviation describes the spread of observations around a mean, while a standard error describes the estimated precision of the mean under a statistical model. Those quantities answer different questions. The registry does not report a mean absolute prediction error estimate or a measure of its dispersion or precision.
How do planning calculations differ from trial results?
Sample-size calculations are planning illustrations, not observed outcomes. A calculation based on an observed effect asks what sample size might be needed to detect an effect under assumptions such as a significance level, allocation pattern, and statistical approximation. It does not establish that the study had that power before it began, and it is not “observed power.” The assumptions described for planning illustrations include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect set as a stated fraction of the observed effect. These hypothetical two-arm assumptions do not describe the listed single-group observational design as a randomized comparison. The registry does not report the study’s own sample-size justification.
Power is a design-stage probability under a particular model and assumed effect. It is not a measure of how convincing a completed result is. Once data are collected, estimates and their uncertainty are more informative than a post hoc power calculation. Since the observed primary endpoint effect and its analysis are not reported in the registry record, the planning assumptions cannot supply a missing outcome estimate.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary endpoint and several secondary outcomes, including multiple refractive thresholds, mean absolute prediction error, and axial-length subgroup measures. Testing or interpreting many outcomes can raise a multiplicity issue: the more statistical comparisons considered, the greater the chance that some appear notable by chance alone. General approaches include specifying a primary hypothesis in advance, adjusting for multiple testing, or treating secondary findings as exploratory. The registry record does not report a multiplicity strategy, a hierarchy among secondary outcomes, or inferential analyses.
The record lists four outcome measures and zero analyses. It does not report whether all planned outcomes were collected, whether any were omitted, or how outcome reporting was determined. The intended assessment includes postoperative follow-up at 5-8 weeks, while the primary endpoint timeframe is recorded as 2 months postoperative; the relationship between these descriptions is not explained.
Missing-data handling is not reported in the registry record. The record does not give the number of eyes with unavailable postoperative refraction, reasons for missing measurements, exclusions from analysis, or whether any imputation method was used. For a proportion, excluding eyes without an observed refraction can change the denominator and potentially the interpretation if missingness is related to outcome. The number of participants or eyes in each analysis population is also not reported.
Analysis populations are groups defined for statistical analysis, such as all enrolled participants or those with an evaluable endpoint. The registry does not specify an analysis population for the primary outcome or describe how participants and eyes were counted. These omissions limit the ability to assess selection effects, reproducibility, and the precision of any result.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Argos Biometer | 0 | 523 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Argos Biometer | 0 of 523 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Argos Biometer | 0 of 523 |
The registry reports the Argos Biometer group with 523 participants at risk for serious adverse events and 0 affected; it also reports 523 at risk for other adverse events and 0 affected. Deaths are recorded as 0. These are the posted counts for the categories and group in the record. They are not outcome estimates of refractive accuracy and should be read separately from the primary endpoint.
A zero count means that no events are recorded in that category in this registry entry. It does not establish that the intervention has no risk or that no event occurred outside the registry’s definitions, observation period, or reporting process. The record does not give definitions of serious or other adverse events, the period and method of collection, or details of event review. It also does not report a more detailed breakdown of adverse events. The safety figures therefore describe what the registry records, while leaving the scope and completeness of surveillance unclear.
12. What the Result Does, and Does Not, Mean
The record identifies a prospective observational study of refractive accuracy using Argos preoperative biometry with the Barrett TAL formula after cataract surgery. It defines a primary measure: the percentage of eyes whose postoperative manifest spherical equivalent refraction is within ±0.50 D at 2 months postoperative. It also lists other refractive accuracy outcomes and reports enrollment of 523 participants.
Those design details do not provide the primary endpoint result. The percentage meeting the threshold, the number of eyes analyzed, and any measure of precision are not reported in the registry record. No numerical conclusion about the observed refractive accuracy can therefore be drawn from the posted record. Completed status does not fill that information gap.
Even if an outcome estimate were available, the observational single-group design would describe outcomes in the studied cohort rather than establish a causal advantage over another device, formula, or strategy. There is no concurrent comparator group listed. A result would also need to be interpreted in light of the study setting, participating surgeons and sites, the analyzed population, missing measurements, and the method used to account for any related measurements from the same participant. Those analytic details are not reported in the registry record.
The endpoint’s threshold is useful for classifying whether a refractive measurement meets a specified criterion, but it is not a complete summary of every measurement. The secondary outcomes could provide complementary information about error magnitude and results across axial-length categories, but their values are not posted in the registry record.
The safety entry records zero serious adverse events, zero other adverse events, and zero deaths in the stated group. These counts should not be taken as proof of absence of risk; the registry does not describe the event definitions or surveillance details. Overall, the record documents the study question and design but does not include the outcome reporting required to assess the primary endpoint’s observed value or precision.
13. Why This Trial Matters Statistically
This study raises a statistical question that is relevant to clinical measurement research: how to describe prediction accuracy using both a threshold-based proportion and measures of error magnitude. A percentage meeting a refractive tolerance is straightforward to communicate, while mean absolute prediction error captures the average size of deviations without retaining their direction. Considering both types of measure can give a more rounded description than either alone, provided their estimates and uncertainty are reported.
The record also highlights a distinction between participant counts and eye-level outcomes. Enrollment is reported as 523, whereas the primary endpoint is defined in eyes. For a transparent interpretation, readers need the number of eyes assessed, the handling of participants who contribute more than one eye, and the denominator used for each outcome. Those details are not reported in the registry record.
Prospective, multicenter, multi-surgeon observation can document outcomes across the settings included in a study. It does not remove the need to consider the limitations of an uncontrolled design. Without a comparator, outcomes cannot establish a relative difference attributable to the device or formula. Statistical methods cannot create a control group or fully resolve confounding that was not measured.
The record is also a useful reminder that a completed study registration and an interpretable result are not the same thing. The primary endpoint is defined, but its observed estimate, uncertainty, and analysis are absent from the registry record. Reporting participant flow, missing outcomes, outcome estimates, and analysis methods would be necessary for readers to evaluate precision and assess how well the findings apply beyond the study cohort.
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.
Several trial-specific limitations constrain interpretation of the registry record. It identifies an observational study and does not list a concurrent comparator. The Argos Biometer group therefore cannot serve as a randomized control comparison, and the record cannot establish a relative effect against another device or formula.
The main limitation is that the primary endpoint result is not reported in the registry record. There is no posted percentage, confidence interval, denominator, or analysis for the outcome. The registry lists 523 participants enrolled, but does not report how many eyes contributed data, how many participants completed postoperative assessment, or whether more than one eye per participant was analyzed. This prevents assessment of both the observed accuracy and the precision of its estimate.
The record does not report missing-data procedures, analysis populations, exclusions, or the number of observations available for each secondary outcome. It also does not report the statistical analysis plan, multiplicity handling, or methods for accounting for any correlation between eyes from the same participant. These details matter for understanding how outcome estimates were produced and how robustly they can be interpreted.
The registry describes assessments at 5-8 weeks postoperatively and gives the primary endpoint timeframe as 2 months postoperative, without explaining the relationship between those descriptions. It does not provide participant characteristics, detailed eligibility criteria, or information about the representativeness of the enrolled cohort. As a result, the range of clinical settings and participants to which any eventual findings might apply cannot be assessed from this record alone.
Finally, the adverse-event counts are not accompanied by definitions or surveillance details. Zero recorded events in the listed categories should therefore be read as registry counts, not as a comprehensive characterization of safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Accuracy of the New Barrett TAL Formula With the Argos Measurements: A Multicenter Prospective Study — NCT06085131.
- Registry record last updated 2026-05-27; status last verified 2026-04.
- Results first posted 2026-05-27.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry describes NCT06085131, a prospective, multicenter, multi-surgeon observational study of refractive accuracy using Argos biometry with the Barrett TAL formula after cataract surgery. Enrollment is 523, and the status is completed. The recorded study start is 2023-10-31, with primary completion on 2025-01-29.
The primary endpoint is the percentage of eyes with postoperative manifest spherical equivalent refraction within ±0.50 D at 2 months postoperative. Secondary outcomes include other refractive thresholds, mean absolute prediction error, and axial-length subgroup measures. The registry lists four outcome measures and zero analyses. The primary and secondary outcome results are not reported in the registry record.
The listed group is Argos Biometer, and no like-for-like comparator is described. The registry records 0 serious adverse events, 0 other adverse events, and 0 deaths, with 523 at risk in each adverse-event category. The record does not provide detailed analysis methods, missing-data handling, or adverse-event surveillance details.