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

Starting soon

Conditions studied: Pseudophakia, Refractive Error

In brief

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.

Key facts

Study ID

NCT07724795

Run by

Vienna Hospital Association

People needed

200

Starts

2026-08-01

Expected to finish

2027-07-01

Last updated by the study team

2026-07-24

Who can join

Age: any. Sex: any. Healthy volunteers: not accepted.

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…

• - Interval ocular surgery on the study eye since the original cataract surgery that may affect refraction or IOL position (e.g., corneal refractive surgery, IOL exchange or repositioning, secondary IOL implantation, or any intraocular surgery). Uncomplicated YAG laser capsulotomy without IOL repositioning is not an exclusion criterion
• 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
• Note: macular pathology is not an exclusion criterion; macular status is documented on OCT and analyzed as a covariate.

Where it is running

• Klinik Hietzing, Augenabteilung — Vienna, State of Vienna, Austria

Full record on ClinicalTrials.gov

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