IOL Power Formula Prediction Accuracy at the Extremes of Axial Length: A Prospective Outcome Verification Study

NCT07724795 | Not Yet Recruiting

• 1 other identifier: MA_15_EK_26_128_VK
• Study Type: observational
• Target: 200
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Pseudophakia; Refractive Error

Keywords

Intraocular lens power calculation; IOL formula; Axial length; Short eye; Long eye

Outcome Measures

Primary Outcomes (1)

• 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).

  Single study visit, at least 3 months after cataract surgery

Study Arms (2)

Short axial length stratum (AL < 22.0 mm)

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

Long axial length stratum (AL > 26.0 mm)

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

Interventions

Standardized postoperative outcome visit DIAGNOSTIC_TEST

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.

Long axial length stratum (AL > 26.0 mm); Short axial length stratum (AL < 22.0 mm)

Eligibility Criteria

• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

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.

You may qualify if:

• \- Participation in the retrospective IOL power formula comparison study at the extremes of axial length (pseudonymized study ID assigned; complete preoperative biometry and archived formula outputs for all eight formula pathways)
• Cataract surgery with a spherical (non-toric) IOL of one of the three reference models (HOYA Vivinex XY1, HOYA Vivinex Impress XY1-EM, or Johnson \& Johnson Tecnis 1-Piece DIB00) at the study center between January 2022 and December 2025
• Preoperative axial length below 22.0 mm (short stratum) or above 26.0 mm (long stratum), measured on IOLMaster 700
• Documented implanted IOL model and power available from the operative record
• At least 3 months since cataract surgery at the time of the outcome visit
• Written informed consent for the outcome visit, including linkage of newly acquired postoperative data with the previously collected, pseudonymized preoperative planning data

You may not qualify if:

• Implanted IOL not matching one of the three reference platforms (e.g., toric, multifocal or EDOF IOL, a different monofocal platform, or a sulcus-fixated IOL)
• Toric IOL implantation
• Acute ocular pathology preventing reliable refraction or biometric measurement
• Cognitive or physical limitations precluding standardized subjective manifest refraction
• Documented intraoperative complication with confirmed or suspected IOL malpositioning (e.g., posterior capsule rupture with vitreous loss, zonular dialysis requiring a capsular tension ring, sulcus placement)
• Withdrawal of informed consent

Sponsors & Collaborators

• Vienna Hospital Association: lead

Study Sites (1)

Klinik Hietzing, Augenabteilung

Vienna, State of Vienna, 1130, Austria

Location

MeSH Terms

Conditions

Pseudophakia; Refractive Errors

Condition Hierarchy (Ancestors)

Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Eye Diseases

Central Study Contacts

Michal Klimek, MD

CONTACT

+436504607496; klimek.michael@gmx.at

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 6 Months
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Head of the Department

Study Record Dates

• First Submitted: July 14, 2026
• First Posted: July 24, 2026
• Study Start: August 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): July 1, 2027
• Last Updated: July 24, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

AU (1)