An observational study in Pseudophakia and Refractive Error, sponsored by Vienna Hospital Association. Not yet recruiting at 1 site in Austria. Per ClinicalTrials.gov, last updated 2026-07-24.
Sponsored by Vienna Hospital Association · Observational
This single-center, prospective, cross-sectional study evaluates how accurately eight modern intraocular lens (IOL) power calculation formulas predicted the postoperative refractive result in eyes with extreme axial length after cataract surgery. Patients previously operated at the study center who had a very short (axial length \< 22.0 mm) or very long (> 26.0 mm) eye and received a spherical monofocal IOL are invited to a single, non-invasive outcome visit. At this visit, standardized manifest refraction, optical biometry, corneal tomography, slit-lamp examination and, in long eyes, macular OCT are performed. The measured postoperative spherical equivalent is compared with the residual refraction that each of the eight formulas had predicted for the actually implanted IOL power, separately in short and long eyes. The study aims to identify which formula predicts the postoperative outcome most accurately at the extremes of axial length, where formula choice is most consequential and least well studied.
Modern IOL power formulas achieve high refractive predictability in average-length eyes but deteriorate at the extremes of axial length, where effective lens position modelling diverges most between formulas. A preceding retrospective study at this center quantified the formula-dependent variability of IOL power recommendations at the axial length extremes using fully standardized biometric inputs; however, planning discrepancy alone does not indicate which formula's recommendation yields the better clinical outcome. This prospective outcome verification study closes that gap by linking a standardized postoperative assessment to the pre-existing, pseudonymized preoperative planning dataset.
Design: single-center, prospective, cross-sectional, observational (paired within-eye) study. From the retrospective source cohort (approximately 927 short and 769 long eyes; approximately 1,000-1,200 patients; index surgeries January 2022-December 2025), a stratified random sample of 200 patients is drawn (110 short stratum, 90 long stratum; 55:45 ratio) and invited to a single outcome visit. Each eligible eye contributes up to eight paired, formula-specific prediction errors that differ only by the calculation formula, while the postoperative reference (manifest refraction) and all preoperative inputs are held constant. Eyes are stratified a priori into a short (AL \< 22.0 mm) and a long (AL > 26.0 mm) stratum and analyzed separately.
Formulas evaluated: Barrett Universal II, Cooke K6, EVO 2.0, Hill-RBF 3.0, Hoffer QST, Kane and PEARL-DGS (via the ESCRS IOL calculator), and the stand-alone Ladas Super Formula 2.0.
Outcome visit (single visit, all non-invasive standard ophthalmic techniques, no study-mandated therapy, medication or surgery): uncorrected and best-corrected distance visual acuity, IOLMaster 700 optical biometry, CASIA2 and Pentacam AXL corneal tomography, autorefraction and standardized subjective manifest refraction (primary outcome measure), slit-lamp examination with posterior capsule opacification grading, and macular OCT (obligatory in the long stratum, recommended in the short stratum).
Primary analysis: for each formula, the spherical equivalent prediction error (SE-PE = measured postoperative spherical equivalent minus the residual spherical equivalent predicted for the actually implanted IOL power step) is computed and the absolute error (\|SE-PE\|) compared globally across the eight formulas using the Friedman test, with post-hoc pairwise Wilcoxon signed-rank tests (Holm-corrected, 28 formula pairs), separately in each axial length stratum. The primary accuracy metric per formula is the median absolute prediction error.
All data are processed in pseudonymized form and linked via a study ID and laterality, in accordance with the Declaration of Helsinki (2024), ICH-GCP, and the GDPR. The study is reported per STROBE and is registered on ClinicalTrials.gov prior to the start of recruitment.
54 studies on the registry are indexed under Pseudophakia; 8 are open to participants now.
This study's planned enrollment of 200 is above the median of 71 across 26 observational studies indexed under Pseudophakia.
Browse Pseudophakia studies →Vienna Hospital Association is the lead sponsor of 11 studies on the registry; 7 are open to participants now.
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Adults previously enrolled in the retrospective IOL power formula comparison study at the extremes of axial length at the study center, who underwent cataract surgery with a spherical (non-toric) monofocal IOL (HOYA Vivinex XY1, HOYA Vivinex Impress XY1-EM, or Johnson \& Johnson Tecnis 1-Piece DIB00) between January 2022 and December 2025, and whose preoperative axial length was below 22.0 mm or above 26.0 mm. A stratified random sample of 200 patients (110 short-eye, 90 long-eye) is drawn from this source cohort and invited 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:
Note: macular pathology is not an exclusion criterion; macular status is documented on OCT and analyzed as a covariate.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Pseudophakic eyes with a preoperative axial length below 22.0 mm that received a spherical monofocal IOL. These eyes undergo the standardized postoperative outcome visit; the measured spherical equivalent is compared with each formula's prediction for the implanted IOL power.
Diagnostic Test: Standardized postoperative outcome visit
Pseudophakic eyes with a preoperative axial length above 26.0 mm that received a spherical monofocal IOL. These eyes undergo the standardized postoperative outcome visit (including obligatory macular OCT); the measured spherical equivalent is compared with each formula's prediction for the implanted IOL power.
Diagnostic Test: Standardized postoperative outcome visit
A single, non-invasive multimodal assessment: uncorrected and best-corrected distance visual acuity, IOLMaster 700 optical biometry, CASIA2 and Pentacam AXL corneal tomography, autorefraction and subjective manifest refraction, slit-lamp examination with posterior capsule opacification grading, and macular OCT. No therapeutic intervention, medication or surgery is performed.
Spherical equivalent prediction error (SE-PE) across eight IOL power formulas, compared within each axial length stratum
For each eye, SE-PE is calculated as the measured postoperative spherical equivalent (standardized manifest refraction) minus the residual spherical equivalent predicted by each formula for the actually implanted IOL power step. The absolute prediction error (\|SE-PE\|) is compared globally across the eight formulas (Barrett Universal II, Cooke K6, EVO 2.0, Hill-RBF 3.0, Hoffer QST, Kane, PEARL-DGS, Ladas Super Formula 2.0) using the Friedman test, with post-hoc pairwise Wilcoxon signed-rank tests (Holm-corrected, 28 formula pairs), performed separately in the short (AL \< 22.0 mm) and long (AL \> 26.0 mm) strata. The primary accuracy metric per formula is the median absolute prediction error (MedAE).
Time frame: Single study visit, at least 3 months after cataract surgery
Plan to share: No
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This study is not yet recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
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Vienna Hospital Association