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 Clinical Study to Evaluate the RxSight Light Adjustable Lens With the Light Delivery Device in Subjects With Preoperative Corneal Astigmatism (NCT03771352), a na na study. The primary outcome is Uncorrected Distance Visual Acuity (UCDVA) of 20/20 or Better.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03771352 |
| Phase | NA |
| Condition | Cataract |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 55 |
| Arms in the primary outcome | n/a |
| Lead sponsor | RxSight, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
Patients undergoing cataract surgery with preoperative corneal astigmatism were the intended study population. The record describes an effectiveness population based on observed data without treatment-related protocol deviations. The registry enrollment is 55; the primary endpoint is measured in eyes, so the enrollment figure and the endpoint unit should not be treated as interchangeable.
Intervention
Eligible patients were to receive the RxSight Light Adjustable Lens (RxLAL) intraocular lens. The study evaluated vision and quality of vision after implantation and UV light treatments using the Light Delivery Device. The listed intervention is a device.
Comparator
The study is listed as single-group, with no masking and no randomized allocation. It therefore has no concurrent comparison group in the registry record. The findings cannot be read as a randomized comparison with another lens, procedure, or care strategy.
Primary question
At 6 months postop, what proportion of eyes had monocular uncorrected distance visual acuity of 20/20 or better after the lens implantation and light treatments? The endpoint title and definition are reported, but the observed count and percentage are not reported in the registry record.
The clinical question is about an observed visual-acuity outcome after a treatment sequence, not a contrast between assigned interventions. The study summary also describes assessment of quality of vision at the same follow-up point, but the primary endpoint is the threshold-based visual-acuity measure. That distinction matters: a threshold outcome describes whether an eye meets a specified acuity category, whereas quality of vision is a separate outcome and should not be inferred from the acuity measure.
3. Trial Design
This was a prospective, multicenter clinical study of the RxSight Light Adjustable Lens with the Light Delivery Device in subjects with preoperative corneal astigmatism. The registry classifies it as a single-group study with no masking and allocation recorded as NA. It is marked completed. The study dates are start 2018-06-19 and primary completion 2019-07-01.
The planned intervention was implantation of the RxSight RxLAL intraocular lens in eligible patients, followed by light treatments. The brief summary describes assessing far vision without glasses and quality of vision after treatment, with assessment 6 months postoperatively after completion of all light treatments. The primary endpoint is specifically uncorrected distance visual acuity of 20/20 or better, measured in eyes at 6 months postop.
Registry enrollment is 55. This is a participant enrollment figure, while the primary outcome is counted in eyes. The safety record separately lists 101 at risk in its adverse-event group. These are different reported quantities and units; the record does not explain their relationship, so they should not be substituted for one another or combined.
The study is not a randomized comparison. Its single-group design means the registry record can describe outcomes observed after the intervention, but it does not establish a treatment contrast against a concurrent control. The record lists phase as NA. It does not report a protocol sample-size justification, details of interim analyses, or a statistical analysis plan. Although a planning illustration accompanies the posted material, its stated equal-allocation, two-arm assumptions do not describe the listed single-group study and should not be mistaken for the trial’s design.
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 | RxSight RxLAL IOL |
|---|---|
| STARTED | 55 |
| COMPLETED | 51 |
| NOT COMPLETED | 4 |
Reasons for not completing this period:
| Reason | RxSight RxLAL IOL |
|---|---|
| Screen failure | 2 |
| Withdrawal by Subject | 2 |
Analysis population for the primary outcome, as defined in the registry: A modified Effectiveness (m-Effectiveness) population was used for all effectiveness analyses which includes all observed data without treatment related protocol deviations.
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 | RxSight RxLAL IOL |
|---|---|---|
| Participants analysed | 51 | |
| Age, Continuous | years | 68.4 (SD 9.7) |
| Sex: Female, Male: Female | Participants | 26 |
| Sex: Female, Male: Male | Participants | 25 |
| Race/Ethnicity, Customized: Asian | participants | 0 |
| Race/Ethnicity, Customized: Black or African American | participants | 0 |
| Race/Ethnicity, Customized: White | participants | 51 |
| Region of Enrollment: United Kingdom | participants | 8 |
| Region of Enrollment: Germany | participants | 43 |
| Primary Eyes Enrolled: OD | Eyes | 26 |
| Primary Eyes Enrolled: OS | Eyes | 25 |
| Fellow Eyes Enrolled: OD | Eyes | 24 |
| Fellow Eyes Enrolled: OS | Eyes | 26 |
6. Primary Endpoint
The registry lists the primary outcome as Uncorrected Distance Visual Acuity (UCDVA) of 20/20 or Better, measured over at 6 months postop.
| 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 count of eyes with monocular uncorrected distance visual acuity (UCDVA) of 20/20 or better at 6 months postop. It is expressed as a percentage of eyes, according to the endpoint description. Uncorrected distance acuity assesses far vision without glasses; the threshold classifies eyes according to whether their measured acuity reaches the specified level. The outcome unit is eyes rather than participants.
A threshold endpoint can be clinically interpretable because it describes the share of eyes meeting a defined visual-acuity benchmark. It does not, by itself, describe the full distribution of acuity measurements, changes from baseline, or the experience of each participant. Nor does it capture quality of vision, which the study summary identifies as another assessment. The registry record does not report the observed number or percentage of eyes meeting the endpoint, or the underlying acuity distribution. Those values are therefore not reported in the registry record, and the endpoint definition alone cannot establish the study’s observed visual result.
The stated analysis population is a modified Effectiveness population, described as including all observed data without treatment-related protocol deviations. The record does not further explain how that population was operationalized for this eye-level outcome, including how multiple eyes from a participant were handled. That matters when interpreting an eye count, because eye-level observations need not represent independent participants.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a relevant, clearly defined endpoint: the proportion of eyes with monocular uncorrected distance visual acuity of 20/20 or better at 6 months postop. However, the posted registry record does not include the observed count or percentage for this endpoint. It therefore does not support a quantitative description of how many eyes met the threshold, how common the outcome was, or how precisely it was estimated. The endpoint title is not itself an outcome result.
The study enrolled 55 and is classified as single-group. Without a concurrent comparison group, an observed outcome would describe what was recorded among the analyzed eyes after implantation and light treatments. It would not, on its own, show what would have occurred without the intervention or under another treatment. Differences from an external benchmark would also need a prespecified and appropriate comparison framework; none is reported in the registry record.
Precision cannot be assessed for the primary endpoint because the result and a confidence interval are not reported in the registry record. General statistical interpretation: a confidence interval gives a range of values compatible with the observed data under the method’s assumptions. Its width helps convey uncertainty, but it does not resolve systematic limitations such as selection, measurement, or lack of a control group. No interval can be reconstructed from the endpoint description alone.
The endpoint is measured in eyes, whereas enrollment is reported in participants. The safety group lists 101 at risk, but that figure does not provide the primary endpoint denominator and should not be repurposed as one. The relationship between participants and eyes, the number of eyes contributing to the effectiveness analysis, and the handling of correlated eyes are not reported in the registry record. Consequently, even if a percentage were available elsewhere, its denominator and precision would need to be checked before interpretation.
The study summary says visual acuity and quality of vision were assessed after completion of light treatments, with follow-up at 6 months. The registry record lists three outcome measures, but does not report the primary outcome result or the results of the other measures in the registry record described. No inference about quality of vision should be drawn from the primary acuity endpoint. Likewise, a result at one follow-up point would not establish how outcomes changed over time unless the relevant longitudinal data were reported.
The safety record includes serious and other adverse-event counts, but those data answer a different question from the visual-acuity endpoint. They should be read separately and in light of the listed safety population and definitions. Neither the effectiveness endpoint nor the adverse-event counts alone establish a causal treatment effect. The most defensible reading is therefore limited: the registry describes a completed single-group study and specifies its primary visual endpoint, but does not report the primary result needed to quantify that endpoint.
9. Statistical Methods Explained
The registry describes the study as single-group, with allocation NA and masking NONE. General statistical explanation: randomization can help balance measured and unmeasured factors between treatment groups, while masking can limit some forms of measurement or behavior bias. Neither feature creates a comparison in a single-group study. Because no concurrent control group is listed, the design is suited to describing outcomes observed in the study group, but it cannot by itself isolate the effect of the lens and light-treatment sequence from other influences.
What does the endpoint count?
The primary measure is a count of eyes meeting the UCDVA threshold of 20/20 or better at 6 months postop. The description says the count is expressed as a percentage of eyes. General statistical explanation: a proportion is the number meeting a defined condition divided by the number assessed for that condition. Both parts are needed for interpretation. The record gives the endpoint definition but does not report the observed count, percentage, or endpoint denominator, so none of those quantities can be interpreted from the registry record.
The unit is eyes, while enrollment is reported as 55 participants. These units are not interchangeable. If more than one eye from a participant contributes, outcomes from the same participant may be related. General statistical explanation: treating related observations as independent can make uncertainty appear smaller than it is. The registry record does not describe the number of eyes analyzed or how within-participant dependence was handled. No assumption about one eye per participant or the analysis method is warranted.
What does an interval add?
General statistical explanation: a confidence interval expresses uncertainty around an estimate using a stated statistical method and its assumptions. For a proportion, it can show the range of values compatible with the observed data under that method. A narrow interval generally indicates greater statistical precision than a wide interval, but precision is not the same as freedom from bias. The primary endpoint result and its interval are not reported in the registry record, so the precision of the estimated proportion cannot be assessed.
The record does not report a statistical analysis plan or a confidence-interval method. No particular model, adjustment, or interval construction should be attributed to the investigators. In particular, there is no basis to describe the reported endpoint as adjusted, to infer a planned subgroup analysis, or to claim that a particular approach to correlated eyes was used.
How should a single-group result be interpreted?
General statistical explanation: a single-group estimate is descriptive of the analyzed group at the measured time point. A comparison with a historical benchmark can be informative only when the benchmark, eligibility criteria, outcome definition, and timing are sufficiently comparable, and when the comparison is framed with its limitations. The registry record does not specify such a benchmark. The endpoint description also does not report a baseline acuity result or a change-from-baseline analysis.
The study summary describes assessment after all light treatments and at 6 months postoperatively. That timing defines the intended endpoint assessment, but the registry record does not say how timing deviations or incomplete follow-up were handled. It also does not report an interim-analysis plan. These omissions prevent assessment of whether outcome availability or analysis choices could have influenced the reported result, which is itself not present in the registry record.
What can the planning illustration tell readers?
A planning illustration is conceptually different from an observed trial result. General statistical explanation: sample-size planning asks how many observations might be needed under stated assumptions to detect a specified effect with a chosen error rate and power. A planning calculation does not reveal the probability that the completed study’s hypothesis is true, and it is not observed power. Here, the stated illustration uses a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects expressed as fractions of the observed effect. It is described as planning based on the observed effect, not as the trial’s own design.
The listed trial design is single-group, so equal allocation between two arms does not match the registry design. The illustration should not be read as a reconstruction of the study’s enrollment rationale or as a direct sample-size prescription for this study. The registry record does not report its own sample-size justification, and the primary effect estimate needed to evaluate the illustration is not reported in the registry record. No observed-power claim follows from such planning assumptions.
Why do analysis populations matter?
The registry identifies a modified Effectiveness population for effectiveness analyses and defines it as including all observed data without treatment-related protocol deviations. That wording identifies the stated population concept, but does not fully specify how participants or eyes entered the primary endpoint analysis, how deviations were classified, or what happened to missing outcome data. General statistical explanation: excluding observations based on post-enrollment events can affect comparability and may introduce bias if the excluded observations differ systematically from those retained. The record does not provide the details needed to evaluate that possibility.
There are three outcome measures listed and no analysis entries. Without reported endpoint estimates, uncertainty measures, analysis methods, and denominators, statistical interpretation must remain focused on the design and the limits of the available record rather than on a claim about the measured effect.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists three outcome measures, but does not report a multiplicity strategy, such as a hierarchy of endpoints or an adjustment to account for multiple statistical tests. It also does not report an analysis plan describing which outcomes were confirmatory or exploratory. Without that information, it is not possible to determine how the investigators intended to control the chance of false-positive findings across multiple outcomes. No claim about statistical significance across outcomes is supported by the record.
Missing-data handling for the primary endpoint is not reported in the registry record. The endpoint is specified at 6 months postop, but the record does not describe the number of eyes assessed at that visit, reasons for unavailable measurements, or any imputation or sensitivity analyses. General statistical explanation: missing outcomes can affect both the estimate and its uncertainty, particularly when the availability of an outcome is related to the outcome itself or to participant characteristics. The extent or direction of any such effect cannot be inferred.
The stated modified Effectiveness population includes all observed data without treatment-related protocol deviations. The registry record does not explain how deviations were identified, how many observations were excluded, or how that population was applied to the eye-level endpoint. It also does not report whether analyses included all enrolled participants or a different subset. Enrollment of 55 should therefore not be assumed to be the denominator for the primary outcome.
Because the design is single-group, multiplicity and missingness are only part of the interpretive limits. The absence of a concurrent comparison also restricts causal conclusions. Together with the missing endpoint result and analysis details, these gaps mean that the registry record cannot support a complete assessment of the planned inferential strategy or the robustness of the primary finding.
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 |
|---|---|---|---|
| RxSight RxLAL IOL | 2 | 101 | 2.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| RxSight RxLAL IOL | 0 of 51 |
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 |
|---|---|
| RxSight RxLAL IOL | 28 of 101 |
Most frequent serious adverse event terms
| Event term | Organ system | RxSight RxLAL IOL |
|---|---|---|
| IOL Explant | Surgical and medical procedures | 1 of 101 |
| Gastritis with diarrhea | Gastrointestinal disorders | 1 of 51 |
Most frequent non-serious adverse event terms
| Event term | Organ system | RxSight RxLAL IOL |
|---|---|---|
| Non-clinically significant cystoid macular edema | Eye disorders | 6 of 101 |
| Diabetic macular edema | Eye disorders | 3 of 101 |
| Posterior Capsular Opacity | Eye disorders | 3 of 101 |
| Loss of BSCVA of ≥ 10 letters due to dry Eye | Eye disorders | 2 of 101 |
| Clinically significant cystoid macular edema | Eye disorders | 2 of 101 |
| Conjunctivitis | Eye disorders | 2 of 101 |
| Cornea Epithelialized with SPK | Eye disorders | 2 of 101 |
| Giant cells on anterior surface of IOL | Eye disorders | 2 of 101 |
| Loss of BCDVA due to Posterior Capsular Opacity | Eye disorders | 2 of 101 |
| Corneal Edema | Eye disorders | 1 of 101 |
Serious events with the highest arm-level rate: gastritis with diarrhea (2.0%), iol explant (1.0%).
The safety record lists the RxSight RxLAL IOL group with 101 at risk. It reports 2 serious adverse events and 28 other adverse events, with 0 deaths. The listed serious terms are Gastritis with diarrhea at 2.0% and IOL Explant at 1.0%. These are safety summaries, not measures of visual acuity or treatment effect.
The 101 at risk is the denominator listed for this safety group; the record does not explain how that figure relates to the enrollment of 55 or to the number of eyes. The serious and other adverse-event counts should not be added together or treated as mutually exclusive without definitions and participant-level information. The registry record does not provide event-onset timing, duration, severity beyond the serious classification, relatedness assessments, or details about repeat events.
General statistical explanation: adverse-event percentages describe frequency relative to a stated denominator and can be difficult to interpret without knowing whether the unit is participants or events, how events were coded, and whether a person could experience more than one event. The record gives listed terms and percentages but not those additional details. These figures therefore describe what the registry reports; they do not by themselves establish whether an event was caused by the intervention or characterize risk relative to another treatment.
12. What the Result Does, and Does Not, Mean
The registry record describes a completed study evaluating a device-based treatment sequence in patients undergoing cataract surgery with preoperative corneal astigmatism. Its primary question is whether eyes met the threshold of monocular uncorrected distance visual acuity of 20/20 or better at 6 months postop. This gives readers a defined outcome and assessment time, but the observed endpoint result is not reported in the registry record.
Because the result is absent, it is not possible to state the proportion of eyes meeting the threshold, assess the precision of that proportion, or compare the result with a prespecified target. The study summary also mentions quality of vision, but no result for that measure is included in the registry record described. The outcome definition should not be mistaken for evidence that the threshold was reached by any particular share of eyes.
The single-group design can describe outcomes among those assessed after implantation and light treatments. It cannot show, by itself, what outcomes would have occurred under a different lens, another treatment strategy, or no light treatment. As a result, even a reported favorable outcome would not alone establish that the intervention caused the outcome. The registry record does not report a randomized comparison or a control group.
The enrollment figure is 55 participants, while the primary endpoint is in eyes and the safety record lists 101 at risk. These quantities have different roles, and the record does not explain their relationship. The eye-level denominator, handling of multiple eyes, and missing outcome data are not reported in the registry record. Those omissions limit evaluation of both the estimate and its precision.
The appropriate conclusion is narrow: the registry specifies the study design, intervention, follow-up timing, primary visual-acuity threshold, and some safety counts, but does not report the primary endpoint result. It does not support a claim that the lens or light treatments did or did not achieve a particular visual outcome, nor a comparative claim about their effects.
13. Why This Trial Matters Statistically
This study illustrates why endpoint definitions and endpoint results need to be read separately. The registry states a concrete visual-acuity threshold and follow-up time, which makes the intended primary question understandable. Yet without the observed count, percentage, denominator, and a measure of uncertainty, readers cannot quantify the result or assess how precise it is. A well-defined endpoint is necessary for interpretation, but it is not a substitute for a reported estimate.
The study also highlights the importance of units of analysis. Enrollment is stated in participants, while the primary measure counts eyes. A safety denominator is reported separately. These figures cannot be assumed to represent the same population or unit. When outcomes are measured in eyes, the handling of multiple eyes from the same participant can affect statistical uncertainty, so the analysis population and dependence structure matter.
Its single-group design is another important statistical feature. Such a design can document what was observed after the intervention, but does not include the concurrent contrast needed to distinguish treatment effects from other explanations. This is particularly relevant when readers are tempted to interpret an outcome threshold as proof of benefit. A descriptive outcome and a causal comparison answer different questions.
Finally, the posted record distinguishes study outcomes from a planning illustration. The illustration uses equal allocation between two arms, whereas the registry classifies the trial as single-group. That mismatch reinforces why planning assumptions must be checked against the actual design and cannot be treated as the study’s own enrollment rationale. The record does not report a sample-size justification or statistical analysis plan. Taken together, these features make transparent reporting of denominators, analysis populations, missing outcomes, and estimates especially important for evaluating the study statistically.
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 consequential limitation for interpreting the primary outcome is that the registry record does not report its observed count or percentage. It also does not report the number of eyes assessed or a confidence interval. Thus, the endpoint cannot be quantified or evaluated for statistical precision from this record.
The single-group design has no concurrent control. Outcomes after implantation and light treatments can be described, but causal attribution cannot be established from the design alone. Allocation is listed as NA and masking as NONE. The record does not report procedures intended to reduce selection or measurement bias beyond those design labels.
The primary endpoint is eye-based, while enrollment is participant-based. The registry record does not clarify how many eyes contributed, whether one or both eyes per participant could be included, or how dependence between eyes was handled. It also does not explain the relationship between enrollment of 55 and the safety group’s 101 at risk. Those quantities should not be treated as interchangeable.
Details about missing outcome data and exclusions are not reported in the registry record. Although a modified Effectiveness population is described, the record does not explain its operational application, the number excluded for treatment-related protocol deviations, or sensitivity analyses. The statistical analysis plan, multiplicity approach, and sample-size justification are also not reported.
The registry lists three outcome measures, but does not include analysis entries. The primary visual-acuity result and quality-of-vision findings are not reported in the record described. Safety information is limited to event counts and listed terms; additional context about event timing, repeated events, and relatedness is not reported. These limitations constrain both the completeness and the strength of interpretation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Clinical Study to Evaluate the RxSight Light Adjustable Lens With the Light Delivery Device in Subjects With Preoperative Corneal Astigmatism — NCT03771352.
- Registry record last updated 2021-06-09; status last verified 2021-05.
- Results first posted 2021-05-25.
- 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 record describes NCT03771352, a completed prospective, multicenter, single-group clinical study of the RxSight Light Adjustable Lens with the Light Delivery Device in subjects with preoperative corneal astigmatism. Enrollment is 55. The study is listed as unmasked, with allocation NA and phase NA. The listed study dates are start 2018-06-19 and primary completion 2019-07-01.
The primary endpoint is the count of eyes with monocular UCDVA of 20/20 or better at 6 months postop. The analysis population is described as a modified Effectiveness population using observed data without treatment-related protocol deviations. The registry record does not report the observed primary endpoint result, its denominator, or its precision. The safety group lists 101 at risk, 2 serious adverse events, 28 other adverse events, and 0 deaths. The record also lists Gastritis with diarrhea at 2.0% and IOL Explant at 1.0% among serious terms.
The study can be described as an evaluation of outcomes after the lens and light-treatment sequence, but its single-group design does not supply a randomized treatment comparison. The registry record does not report a statistical analysis plan, missing-data approach, multiplicity strategy, or sample-size justification.