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 Efficacy, Tolerability, and Comfort of 0.3% Hypromellose Eyedrops in Patients Undergoing LASIK Surgery (NCT00909324), a randomized phase 4 study. The primary outcome is Ocular Comfort Level From Baseline to End of Study.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00909324 |
| Phase | Phase 4 |
| Condition | Dry Eye |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 170 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Novartis Pharmaceuticals |
| Results posted | Yes |
2. Clinical Question
Population
Patients undergoing LASIK surgery. The registry lists Dry Eye as the condition and defines the primary outcome population as the Intent-to-Treat population: all patients in the study who received study treatment.
Intervention
Peri-operative 0.3% hypromellose eye drops. The registry lists pre-LASIK and post-LASIK hypromellose interventions, but the arm descriptions are blank, so the full treatment schedules are not reported in the registry record.
Comparator
The study summary describes comparing pre-operative hypromellose with a control receiving no pre-operative lubricant. The registry does not give a complete description of the comparator arm or its other treatment details.
Primary question
Does adding pre-operative 0.3% hypromellose to post-operative comfort care change ocular comfort across the study period, compared with no pre-operative lubricant?
The registry describes the primary outcome as ocular comfort level from baseline to end of study. Participants rated burning sensation, foreign body sensation, itching, watering of eyes, dryness of eyes, and photophobia on a scale of 0 to 10. Higher scores indicated greater discomfort, while a negative change score indicated improvement.
The question is clinically framed around patients’ reported comfort during the pre- and post-operative period, rather than only a clinical sign. The registry also lists Tear Breakup Time and Schirmer’s Test as secondary outcomes. It does not report numerical results for these measures or for the primary outcome, so the record cannot establish the direction or size of any observed difference.
3. Trial Design
The registry identifies this as a Phase 4, randomized, parallel-group study with no masking. Enrollment was 170, and the study status is completed. The study start and primary completion dates are recorded as 2009-08-01 and 2010-01-01.
The stated purpose was to assess tolerability and comfort associated with peri-operative 0.3% hypromellose in LASIK patients, and to assess whether pre-operative drops added to post-operative comfort compared with control without a pre-operative lubricant. The interventions listed are Pre-LASIK 0.3% hypromellose and Post-LASIK 0.3% hypromellose. However, the arm descriptions contain no details. The exact dosing schedules, duration of use, and full contents of each treatment arm are not reported in the registry record.
Random allocation is intended, in general, to reduce systematic differences between treatment groups by assigning participants through a chance process. It does not ensure that groups are identical, and the registry does not describe the randomization method or allocation concealment. With no masking, participants and study personnel were not blinded according to the registry entry. That matters for a subjective comfort rating because expectations or knowledge of treatment may influence reports or assessments; this is a general concern, not evidence that such influence occurred in this trial.
The record defines the primary outcome population as participants who received study treatment. It does not report how many participants were randomized to each arm or give a complete accounting of withdrawals and outcome availability. The adverse-event entry lists at-risk counts of 72 for Pre-LASIK 0.3% hypromellose and 90 for Post-LASIK 0.3% hypromellose. Those safety counts should not be assumed to provide a complete account of enrollment or analysis populations.
The registry lists three outcome measures: the primary ocular comfort measure and the two secondary measures. It records no analyses. The protocol’s statistical analysis plan, sample-size justification, and any interim analyses are not reported in the registry record.
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 | Pre-LASIK 0.3% Hypromellose | Post-LASIK 0.3% Hypromellose |
|---|---|---|
| STARTED | 72 | 90 |
| COMPLETED | 72 | 90 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Intent-to-Treat population: All patients in the study who received study treatment.
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 | Pre-LASIK 0.3% Hypromellose | Post-LASIK 0.3% Hypromellose | Total |
|---|---|---|---|---|
| Participants analysed | 72 | 90 | 162 | |
| Age, Continuous | Years | 26.24 (SD 4.81) | 25.99 (SD 5.06) | 26.10 (SD 4.93) |
| Sex: Female, Male: Female | Participants | 50 | 66 | 116 |
| Sex: Female, Male: Male | Participants | 22 | 24 | 46 |
6. Primary Endpoint
The registry lists the primary outcome as Ocular Comfort Level From Baseline to End of Study, measured over Baseline (Pre-LASIK surgery), Day 1, Day 7 and Day 30 post-LASIK surgery.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is ocular comfort level from baseline to end of study. The registry specifies assessments at Baseline (Pre-LASIK surgery), Day 1, Day 7 and Day 30 post-LASIK surgery. Patients rated six symptoms: burning sensation, foreign body sensation, itching, watering of eyes, dryness of eyes, and photophobia. Each was rated on a scale of 0 to 10. Higher scores meant greater discomfort, and a negative change score meant improvement.
This endpoint captures how patients experience symptoms around surgery. In general, patient-reported measures can add information that is not conveyed by clinical tests alone, because they record the patient’s own account of discomfort. The registry also includes Tear Breakup Time and Schirmer’s Test as secondary outcomes, which concern tear-film and tear-production assessments. The record does not explain how the six comfort ratings were combined, whether each symptom was analyzed separately, or how change across the repeated assessments was summarized.
Although the outcome title refers to change from baseline, the registry provides no means, standard deviations, changes, confidence intervals, or test results. Therefore, the endpoint’s measurement approach is described, but its observed values and the precision of any treatment comparison are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The available registry entry describes the trial question, design, and intended outcome measurements, but it does not provide numerical results for the primary endpoint. It records zero statistical analyses. As a result, there is no posted estimate of the difference in ocular comfort between the study groups, no uncertainty interval, and no reported significance test to interpret. The direction, magnitude, and precision of any primary outcome contrast are not reported in the registry record.
The primary measure is repeated over baseline and post-operative assessment times and covers six symptom parameters. A result for one symptom or time point would not necessarily represent the overall comfort experience across all symptoms and assessments. The registry does not say whether the components were combined, analyzed separately, or handled through another summary approach. It also does not identify a single time point as the sole primary comparison. The record flags the primary outcome as having several categories or time points and not being reduced to one comparison.
In general, a mean describes the average score in a group, while a standard deviation describes variation among participants. A between-group estimate would describe the contrast under a stated analysis, and a confidence interval would communicate the range of values reasonably compatible with the observed data under that method. These are general statistical concepts; no such result or interval is reported for this trial’s primary endpoint.
The enrollment figure is 170, but it is not enough to infer how many participants contributed data to each outcome, how much information was available at each assessment, or how precise a treatment estimate would be. The safety record separately lists 72 at risk in the Pre-LASIK 0.3% hypromellose group and 90 at risk in the Post-LASIK 0.3% hypromellose group. Those counts relate to the recorded adverse-event entries and should not be treated as outcome-analysis denominators without additional information.
The record’s lack of numerical results is not evidence that the groups had the same comfort outcomes, nor does it show that one approach was better. It means the treatment comparison cannot be evaluated from the posted registry results. The same limitation applies to the secondary outcomes: their names are listed, but their values and analyses are not reported.
The study is randomized, which is relevant to the intended comparison, but the record does not include enough detail to assess implementation or the consequences of the open-label design. In general, subjective ratings in an unmasked study can be susceptible to expectation or reporting effects. This identifies a design consideration, not proof of bias in the observed data.
9. Statistical Methods Explained
The registry identifies randomized allocation and a parallel-group model. In general, randomization assigns participants to groups by chance, supporting a comparison that is less affected by systematic selection than a nonrandomized assignment. A parallel design means participants are compared across groups rather than being described as switching through treatments. The registry does not give the randomization procedure, allocation concealment details, or the planned statistical model, so the specific implementation and analysis cannot be assessed from this record.
What does the primary outcome represent?
Ocular comfort is recorded as a continuous measure on a scale of 0 to 10 for six symptoms, with higher scores indicating greater discomfort. The outcome is assessed at baseline and at post-operative visits. The registry describes the primary parameter as a mean and the dispersion measure as a standard deviation. In general, the mean summarizes the group’s average score, while the standard deviation describes how spread out individual scores are around that average. Neither alone gives the uncertainty in a treatment comparison.
The description says a negative change score indicates improvement. That direction matters when reading a change-from-baseline analysis: the sign should be interpreted using the registry’s stated convention, rather than assuming that a positive change is favorable. The entry does not report actual group means, standard deviations, or changes, and it does not explain whether the six symptom items were combined or tested separately.
Why does the analysis need to account for repeated measurements?
In general, repeated assessments from the same participant are related rather than independent. A statistical method that analyzes change over time may need to account for that within-participant relationship. The registry gives assessment times but does not report whether the planned analysis used a repeated-measures model, separate comparisons at each visit, a change score, or another approach. No particular method should be inferred from the measurement schedule alone.
Likewise, the registry lists the primary outcome as having multiple categories or time points and does not reduce it to a single comparison. When several outcomes, symptoms, or time points are tested, the chance of finding at least one apparently notable result can increase. General approaches to multiplicity include defining a primary comparison in advance or adjusting inference across a family of tests. The registry does not report whether any such approach was planned or used.
What can be inferred from the sample-size assumptions?
The record describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. Such an illustration is a planning calculation, not an observed trial result and not observed power. The registry record does not report a trial-specific sample-size justification or the statistical plan behind the study’s enrollment.
In general, sample-size calculations depend on the selected effect, variability assumptions, allocation, and analysis method. A calculation based on an effect observed in the same study is not independent confirmation that the effect is real. The record does not give the numerical outputs of the planning illustration in the registry record for this account, so no participant target for a particular planning scenario can be stated.
What does the absence of analysis results mean?
The registry reports zero analyses and supplies no numerical primary or secondary outcome results. Therefore, there is no estimate to interpret, no confidence interval to assess, and no reported test statistic or p-value. In general, a confidence interval expresses uncertainty around an estimate; a narrow interval indicates greater precision than a wide one, given the same method and assumptions. No interval is reported for this trial.
Standard deviation and confidence interval answer different questions: the former describes variability among observations, while the latter describes uncertainty about an estimated quantity. The registry’s identification of standard deviation as the dispersion measure does not itself provide either the group-level spread or the precision of a between-group contrast. Without posted outcome values and an analysis description, neither can be evaluated.
Finally, the record identifies an unmasked design. In general, lack of masking can matter particularly for subjective outcomes because treatment knowledge may affect reported symptoms or their assessment. Randomization and masking address different potential sources of bias; random allocation does not remove every concern related to open-label reporting. The record does not report procedures intended to reduce such influence.
10. Multiplicity, Missing Data and Analysis Populations
The primary comfort outcome involves six symptom parameters and repeated assessments at baseline, Day 1, Day 7 and Day 30. The registry notes that this outcome has several categories or time points and is not reduced to one comparison. The two secondary outcomes are Tear Breakup Time from baseline to end of study and Schirmer’s Test from baseline to end of study. With several possible outcomes and assessment times, multiplicity is a relevant general statistical concern: repeated testing can make isolated findings harder to interpret as confirmatory evidence.
The registry does not report a prespecified hierarchy of outcomes, an adjustment for multiple comparisons, or whether symptom parameters were combined. The statistical analysis plan is not reported in the registry record. It is therefore not possible to determine how multiplicity was handled or which contrast, if any, was intended as the main inferential test.
Missing-data procedures are also not reported. The record does not explain how incomplete ratings, missed visits, withdrawals, or participants without later measurements were handled. It does not report outcome-specific denominators or the extent of missingness at each visit. In general, missing observations can affect both the number of participants contributing information and the validity of an estimate, depending on why values are absent and how the analysis treats them. No particular missing-data mechanism or method can be inferred.
The primary outcome population is defined as all patients in the study who received study treatment. The registry does not give a detailed account of how that population was used in an analysis, and no analyses are recorded. The randomization-based analysis population, if different, is not reported in the registry record.
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 |
|---|---|---|---|
| Pre-LASIK 0.3% Hypromellose | 0 | 72 | 0.0% |
| Post-LASIK 0.3% Hypromellose | 0 | 90 | 0.0% |
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 |
|---|---|
| Pre-LASIK 0.3% Hypromellose | 0 of 72 |
| Post-LASIK 0.3% Hypromellose | 0 of 90 |
The adverse-event entry lists 72 participants at risk in the Pre-LASIK 0.3% hypromellose group and 90 in the Post-LASIK 0.3% hypromellose group. The recorded number affected by serious adverse events is 0 in each group. The entry also records 0 affected for the other adverse-event category in each group. Death counts are null, which means they are not reported in the registry record; they should not be read as zero.
These figures describe the adverse-event fields recorded in the registry. They do not provide event descriptions, timing, duration, severity gradations, or a detailed account of how adverse events were collected. The registry’s listed at-risk counts also do not establish the number of participants assessed for every outcome or at every visit.
In general, a zero count in a registry field means that no affected participants were recorded in that field; it does not establish that no event could occur or that every possible harm was measured. Without fuller safety methods and follow-up details, the figures should be read narrowly as the posted counts, not as a comprehensive assessment of tolerability.
12. What the Result Does, and Does Not, Mean
The registry describes a randomized study of peri-operative 0.3% hypromellose in patients undergoing LASIK surgery. Its stated aim was to assess tolerability and comfort and to examine whether pre-operative drops added to post-operative comfort compared with a control without pre-operative lubricant. The primary measure was patient-rated ocular comfort across six symptoms and several assessment times.
What the record does not provide is the numerical primary outcome result. There are no posted group means, changes, confidence intervals, or statistical tests in the registry entry, and it records zero analyses. Consequently, the available record does not show the size or direction of a comfort difference, how precise an estimate might be, or whether a statistical comparison supported a difference. The absence of a result is not evidence of no difference.
The listed secondary outcomes are Tear Breakup Time and Schirmer’s Test, but their numerical findings are also not reported in the registry record. The adverse-event entry records zero affected participants for serious adverse events in each listed group, with the associated at-risk counts, while death counts are not reported. These limited entries do not amount to a complete account of clinical outcomes or safety.
General interpretation of a randomized trial depends not only on allocation but also on the exact treatment schedules, analysis methods, outcome completeness, and uncertainty around estimates. The registry identifies the design as unmasked, but gives little detail about implementation and analysis. Those omissions limit how fully the study can be appraised from the registry entry.
Accordingly, the trial’s registered question and measurement approach can be described, but its comparative clinical findings cannot be established from the posted results. No conclusion about treatment effect should be drawn from the enrollment figure or the existence of outcome definitions alone.
13. Why This Trial Matters Statistically
This trial is statistically notable as an example of a registry record that identifies a randomized design and a patient-reported primary outcome but does not report the numerical outcome analyses. Knowing the design and endpoint is necessary for understanding the intended comparison, but neither substitutes for an estimated treatment contrast and its uncertainty.
The outcome structure also highlights a common analytic challenge. Comfort was assessed across six symptoms and multiple time points. Unless the target comparison and method for handling those measurements are clearly specified, readers cannot tell whether results would represent an overall comfort change, a particular symptom, or a particular visit. The registry notes the multiple categories and times but does not identify a single reduced comparison or explain any multiplicity strategy.
The unmasked design is relevant because the primary endpoint relies on patients’ reports of symptoms. In general, subjective outcomes can be influenced by expectations or awareness of treatment. Randomization can help with baseline comparability, but does not by itself resolve concerns related to unmasked reporting. This is a methodological consideration rather than evidence that the ratings were biased.
Finally, the record distinguishes planned measurement from reported evidence. It lists Tear Breakup Time and Schirmer’s Test as secondary outcomes and includes limited adverse-event counts, but no outcome analyses. The statistical lesson is that registry completeness about design and outcomes does not guarantee enough posted data to judge effect size, precision, multiplicity, or missing-data handling. Those are essential elements for interpreting a comparative trial.
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 registry record provides limited detail about the intervention arms. Although pre-LASIK and post-LASIK 0.3% hypromellose are listed and the study summary describes a control without pre-operative lubricant, the arm descriptions are blank. Dosing schedules, use instructions, treatment duration, and other arm-specific details are not reported in the registry record.
The primary outcome description identifies six symptoms, a 0-to-10 scale, and repeated assessment times, but does not explain how the component ratings were summarized or which comparison was primary. The record flags the multiple categories and time points without reducing them to one comparison. It does not report the statistical analysis plan, the handling of multiplicity, or methods for repeated measurements.
Outcome data and analysis results are absent. The registry does not report group values, uncertainty intervals, test results, or outcome-specific participant counts. Missing-data methods, withdrawals, and visit-level completeness are also not reported in the registry record. These omissions prevent assessment of the magnitude and precision of the treatment comparison.
The study is recorded as unmasked, and the primary outcome is subjective. This combination can raise general concerns about reporting or assessment effects, but the registry does not describe safeguards or show whether any such effects occurred. Randomization details and allocation concealment are not reported.
Safety information is limited to the recorded at-risk and affected counts. Event definitions, collection methods, follow-up details, and death counts are not fully available; death counts are null. These limitations mean the adverse-event fields should not be treated as a complete safety assessment.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Efficacy, Tolerability, and Comfort of 0.3% Hypromellose Eyedrops in Patients Undergoing LASIK Surgery — NCT00909324.
- Registry record last updated 2020-08-17; status last verified 2020-07.
- Results first posted 2011-03-24.
- 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.
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18. Record Summary
The registry identifies a completed, Phase 4, randomized, unmasked, parallel-group study with enrollment of 170. It examined peri-operative 0.3% hypromellose in patients undergoing LASIK surgery, with ocular comfort as the primary outcome and Tear Breakup Time and Schirmer’s Test as secondary outcomes.
Ocular comfort was rated for six symptoms on a scale of 0 to 10 at baseline and post-operative assessments. The registry records no statistical analyses and does not report numerical outcome results. It gives limited serious adverse-event counts, while death counts are not reported in the registry record. Treatment-arm details, the statistical analysis plan, missing-data methods, and multiplicity procedures are also not reported.