An observational study in Cataract, sponsored by Vienna Hospital Association. Not yet recruiting. Open to participants aged 18 Years to 100 Years. Per ClinicalTrials.gov, last updated 2026-10-19.
Sponsored by Vienna Hospital Association · Observational
The goal of this observational study is to learn which toric lens calculator best predicts the astigmatism remaining after cataract surgery in adults who received a TECNIS DIU toric intraocular lens (IOL) at Klinik Hietzing, Vienna, between January 2023 and March 2026.
Toric lenses correct astigmatism (an uneven curvature of the cornea) during cataract surgery. The strength of the lens and its orientation in the eye are chosen with online calculators. In an earlier study of the same patients, two widely used calculators - the Johnson \& Johnson toric calculator and the Barrett calculator of the European Society of Cataract and Refractive Surgeons (ESCRS) - recommended different lenses in about 6 out of 10 eyes. It is not known which recommendation leads to the better result.
The main questions it aims to answer are:
Researchers will compare the astigmatism that each calculator predicted for the lens that was actually implanted with the astigmatism measured after surgery.
Participants will:
No treatment, medication or surgery is given as part of this study.
Background In the preceding retrospective paired comparison at the study site (MA15-EK 26-035-VK; 182 eyes of 128 patients with TECNIS DIU toric IOLs, surgery January 2023 to March 2026), all calculator runs used one standardized input set per eye (IOLMaster 700 biometry, CASIA2 anterior keratometry, incision meridian 135 degrees, assumed surgically induced astigmatism 0.40 D). Recommendations of the Johnson \& Johnson toric calculator with posterior corneal astigmatism correction enabled (PCA-ON) and the ESCRS toric calculator with the Barrett engine differed in a clinically relevant way (toric step difference of at least 1 and/or axis difference of at least 10 degrees; ClinRel = 1) in 59.8% of eyes. Discrepancies were driven almost exclusively by step differences, with J\&J recommending the higher step, and were concentrated in with-the-rule eyes (72.3% vs. 5.6% in against-the-rule eyes). Posterior corneal astigmatism magnitude was the strongest predictor of disagreement. Published toric formula comparisons report population-level prediction errors but do not address which calculator is correct in eyes in which calculators disagree.
Procedures Before recruitment, the implanted DIU model and step, the intended implantation axis and the surgeon are extracted from the operative records. All 128 patients of the source cohort are invited in writing, with telephone follow-up after 2 weeks. The outcome visit follows a fixed sequence designed to protect tear-film-sensitive and pupil-dependent measurements: interval history, uncorrected distance visual acuity, iTrace ray-tracing aberrometry, IOLMaster 700, CASIA2 anterior segment OCT, Pentacam AXL, autorefraction and manifest refraction with best-corrected distance visual acuity, and slit-lamp examination (posterior capsule opacification grading, retroillumination of the toric axis, centration and tilt). Manifest refraction is performed by at most two designated refractionists using fogging and Jackson cross-cylinder refinement, with predefined repeat rules for unstable endpoints; the refractionist is masked to ClinRel status, calculator predictions and the implanted step. All cylinder values are recorded in plus-cylinder notation. Outcome data are linked to the pseudonymized retrospective planning dataset via Study ID and laterality. If a calculator's archived output does not show the predicted residual astigmatism for the implanted step, a reconstructive run with the original inputs is performed and flagged.
Statistical analysis The analysis is estimation-based. The primary estimand is the mean paired within-eye difference in Alpins difference vector magnitude between J\&J PCA-ON and Barrett in ClinRel = 1 eyes (one eye per patient, same deterministic eye-selection rule as the retrospective study), reported with a two-sided 95% confidence interval (t-based; BCa bootstrap interval as robustness analysis) and interpreted against a pre-specified zone of practical equivalence of +/-0.125 D, i.e. half of the 0.25 D refraction increment. Paired t-test and Wilcoxon signed-rank test are supportive. Pairwise comparisons across all six calculator pathways are Holm-corrected. Both eyes are analyzed in a sensitivity set using mixed-effects models or generalized estimating equations. Pre-specified sensitivity analyses are restricted to eyes with stable corneas, eyes without prior Nd:YAG capsulotomy, eyes with at least 12 months of follow-up, and eyes without minor intraoperative events, and include a model adjusted for IOL misalignment. A non-responder analysis compares attendees with non-attendees using retrospective data. Reporting follows STROBE.
Sample size The sample is fixed by the source cohort. With an anticipated attendance of at least 80% (100 to 115 patients) and a ClinRel rate of about 60%, 60 to 70 evaluable ClinRel = 1 eyes are expected. Assuming a standard deviation of the paired difference of 0.25 D, about 64 eyes give a 95% confidence interval half-width of at most 0.0625 D (precision target).
Data protection Data are processed in pseudonymized form on the basis of written informed consent (Art. 6(1)(a) and 9(2)(a) GDPR). The re-identification key is stored separately at the study site, and data are retained for at least 10 years.
1,726 studies on the registry are indexed under Cataract; 230 are open to participants now.
This study's planned enrollment of 128 is above the median of 82 across 491 observational studies indexed under Cataract.
Browse Cataract studies →Vienna Hospital Association is the lead sponsor of 11 studies on the registry; 7 are open to participants now.
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Adult patients who underwent cataract surgery with implantation of a TECNIS DIU toric IOL at the Department of Ophthalmology, Klinik Hietzing, Vienna, Austria, between January 2023 and March 2026, and who form the source cohort (128 patients, 182 eyes) of the retrospective toric IOL calculator comparison study (MA15-EK 26-035-VK). All members of the cohort are invited in writing to a single outcome visit.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Adults who underwent cataract surgery with implantation of a TECNIS DIU toric IOL at Klinik Hietzing, Vienna, between January 2023 and March 2026 and who were included in the retrospective toric calculator comparison study (MA15-EK 26-035-VK). Each participant attends one study-specific outcome visit. Pre-specified subgroups: eyes with clinically relevant planning discrepancy between J\&J PCA-ON and ESCRS-Barrett (ClinRel = 1; primary analysis population) versus planning consensus (ClinRel = 0), and astigmatism phenotype (with-the-rule, against-the-rule, oblique).
Other: Standardized Postoperative Outcome Visit · Other: Toric IOL Calculator Pathways (Exposure)
Single non-invasive examination visit (approximately 60-90 minutes), at least 3 months after cataract surgery, in a fixed sequence: uncorrected distance visual acuity, ray-tracing wavefront aberrometry (iTrace), optical biometry (IOLMaster 700), anterior segment OCT tomography (CASIA2), Scheimpflug tomography (Pentacam AXL), autorefraction and standardized manifest refraction with best-corrected distance visual acuity, and slit-lamp examination with posterior capsule opacification grading, toric IOL axis documentation by retroillumination and assessment of centration and tilt. Pupil dilation only after completion of all pupil-dependent measurements. No study-related treatment, medication or surgery.
Archived preoperative toric planning outputs of six calculator pathways, generated from a standardized input set in the preceding retrospective study: Johnson \& Johnson toric calculator with posterior corneal astigmatism correction enabled (PCA-ON) and disabled (PCA-OFF), and the ESCRS toric calculator with the Barrett, Kane, EVO 2.0 and Hoffer QST engines. The residual astigmatism predicted for the actually implanted toric step is compared with the measured postoperative outcome. No treatment is assigned within this study; all lenses were implanted during routine care.
Paired Difference in Alpins Difference Vector Magnitude Between the J&J Toric Calculator (PCA-ON) and ESCRS-Barrett in Eyes With Clinically Relevant Planning Discrepancy
For each eye, the difference vector (DV) is the vector difference (J0/J45 power-vector space) between the residual astigmatism predicted by a calculator for the actually implanted TECNIS DIU toric step and the residual refractive astigmatism measured by standardized manifest refraction (plus-cylinder notation). The paired difference is \|DV J\&J PCA-ON\| minus \|DV Barrett\| (diopters); negative values favor J\&J, positive values favor Barrett. Population: eyes with clinically relevant planning discrepancy (ClinRel = 1: toric step difference ≥1 and/or axis difference ≥10° between the two calculators), one eye per patient. Primary result: mean paired difference with two-sided 95% confidence interval, interpreted against a pre-specified zone of practical equivalence of ±0.125 D; stratified by astigmatism phenotype (with-the-rule, against-the-rule, oblique).
Time frame: Single outcome visit, at least 3 months after cataract surgery
Prediction Accuracy of Six Toric Calculator Pathways (Difference Vector Magnitude)
Magnitude of the Alpins difference vector (D) between the residual astigmatism predicted for the implanted toric step and the manifest refractive astigmatism, for J\&J PCA-ON, J\&J PCA-OFF, ESCRS-Barrett, ESCRS-Kane, ESCRS-EVO 2.0 and ESCRS-Hoffer QST; mean ± SD and median \[IQR\]; pairwise within-eye comparisons of all 15 pathway pairs (Friedman test, Holm-corrected Wilcoxon signed-rank tests); full cohort and by ClinRel status and astigmatism phenotype. Alpins magnitude of error, angle of error and correction index are reported once per eye.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Proportion of Eyes With Difference Vector Magnitude ≤0.50 D and ≤0.25 D per Calculator Pathway
Percentage of eyes with an Alpins difference vector magnitude ≤0.50 D and ≤0.25 D for each of the six calculator pathways, with Wilson 95% confidence intervals; pairwise comparisons between pathways with McNemar tests.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Residual Refractive Astigmatism in J&J-Concordant Versus Barrett-Concordant Eyes (ClinRel = 1)
Manifest refractive cylinder (D) in ClinRel = 1 eyes in which the implanted toric step matched the J\&J PCA-ON recommendation versus eyes in which it matched the Barrett recommendation; Mann-Whitney U test and linear regression adjusted for anterior and posterior corneal astigmatism, astigmatism phenotype, IOL misalignment, posterior capsule opacification grade and time since surgery. Formal comparison only if each group contains ≥10 eyes.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Postoperative Residual Refractive Astigmatism
Manifest refractive cylinder (D, plus-cylinder notation), axis (degrees) and J0/J45 vector components; proportions of eyes with ≤0.50 D, ≤0.75 D and ≤1.00 D; full cohort and ClinRel = 1 versus ClinRel = 0 eyes (unadjusted and confounder-adjusted).
Time frame: Single outcome visit, at least 3 months after cataract surgery
Uncorrected and Best-Corrected Distance Visual Acuity
Uncorrected (UDVA) and best-corrected distance visual acuity (BCDVA) in logMAR, measured monocularly with Snellen optotypes at 6 m; proportions of eyes with ≤0.10 logMAR and ≤0.30 logMAR; correlation between residual refractive cylinder and UDVA.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Toric IOL Rotational Stability
Angular deviation (degrees) between the documented intended implantation axis and the measured postoperative toric IOL axis (slit-lamp retroillumination; CASIA2 as secondary method); proportions of eyes with ≥5° and ≥10° misalignment; association between misalignment and residual refractive astigmatism.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Measured Versus Assumed Surgically Induced Astigmatism
Corneal surgically induced astigmatism (D, degrees), computed as the vector difference between preoperative and postoperative CASIA2 anterior corneal astigmatism (Pentacam AXL as secondary method), compared with the planning assumption of 0.40 D at 135°: magnitude error, angle error and difference vector; association with calculator difference vector magnitude.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Corneal Stability Between Preoperative and Postoperative Measurement
Change in CASIA2 anterior corneal astigmatism magnitude (D) and axis (degrees) between the preoperative and the postoperative measurement within the same analysis zone; proportion of eyes classified as cornea stable (change \<0.50 D and \<15°) with Wilson 95% confidence interval.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Inter-Device Agreement for Postoperative Total Corneal Astigmatism
Agreement between IOLMaster 700 total keratometry, CASIA2 real corneal astigmatism and Pentacam AXL total corneal refractive power: Bland-Altman mean bias and 95% limits of agreement for magnitude, J0 and J45; intraclass correlation coefficients; proportion of eyes with an inter-device difference ≥0.50 D.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Wavefront-Derived Astigmatism Decomposition and Higher-Order Aberrations (iTrace)
Total ocular, corneal and internal astigmatism (magnitude, axis); higher-order aberration RMS, coma, trefoil and spherical aberration at 3.0 mm pupil diameter; Dysfunctional Lens Index; agreement between iTrace total ocular astigmatism and manifest refractive cylinder.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Proportion of ClinRel = 1 Eyes in Which the J&J Calculator Was More Accurate Than Barrett
Proportion of ClinRel = 1 eyes in which the difference vector magnitude of J\&J PCA-ON was smaller than that of Barrett, with Wilson 95% confidence interval and exact binomial test against 50%.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Agreement of Calculator Recommendations With the Retrodictively Optimal Toric Step
Proportion of eyes in which each calculator's recommended toric step matched the step that would have produced the lowest residual astigmatism based on the measured postoperative outcome, with Wilson 95% confidence intervals and Holm-corrected McNemar tests between pathways. Exploratory analysis.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Association Between J&J Decision Margin and Postoperative Outcome
Association between the J\&J PCA-ON decision margin (difference in predicted residual astigmatism between the recommended and the best alternative toric step; \<0.10 D versus ≥0.10 D) and residual refractive cylinder and J\&J difference vector magnitude (Spearman correlation, Mann-Whitney U test, adjusted linear regression).
Time frame: Single outcome visit, at least 3 months after cataract surgery
Predictors of Suboptimal Refractive Outcome
Adjusted odds ratios with 95% confidence intervals from multivariable logistic regression for a suboptimal outcome (residual refractive cylinder \>0.50 D and/or difference vector magnitude \>0.50 D). Candidate predictors: posterior corneal astigmatism, astigmatism phenotype, ClinRel status, J\&J decision margin, IOL misalignment, corneal stability, posterior capsule opacification grade, axial length and time since surgery. A reduced model is used if there are fewer than 10 events per predictor; Firth-penalized regression if separation occurs.
Time frame: Single outcome visit, at least 3 months after cataract surgery
Evaluability per Calculator Pathway
Proportion of eyes evaluable for the difference vector computation per calculator pathway (predicted residual astigmatism for the implanted step available from the archived or a retrospectively reconstructed output), reasons for non-evaluability, and number of reconstructive calculator runs per engine.
Time frame: Single outcome visit, at least 3 months after cataract surgery
No study locations are listed for this record.
Plan to share: No — Individual participant data will not be shared. Participants consent to the processing of their pseudonymized data by the named study investigators only (Art. 6(1)(a) and 9(2)(a) GDPR); sharing with other researchers is not covered by this consent. Aggregate results will be published in a peer-reviewed journal.
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Start is estimated for Nov 2026; primary completion for Mar 2027, 4 months later.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Vienna Hospital Association