Predicted Versus Measured Posterior Corneal Astigmatism In Toric Iol Calculations: A Comparative Study Of Barrett And Evo Formulas
Published 2026 - 44th Congress of the ESCRS
Reference: PP17.11 | Type: Poster | DOI: 10.82333/9ddv-v056
Authors: Dr Dohyeon An* 1 , Dr Joo-Ye Park 1 , Dr Soonwon Yang 1 , Prof. Dr So-Hyang Chung 1
1Ophthalmology,The Catholic University of Korea,Seoul,Korea, Republic Of
Purpose
To compare toric intraocular lens (IOL) calculation performance using predicted versus measured posterior corneal astigmatism (PCA) with Barrett and EVO toric formulas.
Setting
This retrospective study included 146 eyes undergoing toric IOL implantation.
Methods
Toric calculations were performed using Barrett Toric v2.0 and EVO Toric v2.0 with predicted PCA (PPCA) and measured PCA from IOL Master 700 Total Keratometry (MPCA-IOLM) and Pentacam posterior keratometry (MPCA-Pentacam). Refractive astigmatism prediction error (RA-PE) was evaluated using vector analysis. Accuracy, trueness, and precision were compared, along with proportions of eyes within ±0.50 D of RA-PE.
Results
Absolute RA-PE was similar across all methods (median ~0.30–0.35 D). EVO PPCA showed higher precision with the narrowest error distribution, while measured PCA—particularly MPCA-IOLM—demonstrated superior trueness with centroids not significantly different from zero. The percentage of eyes within ±0.50 D of RA-PE ranged from 69% to 77%, with no significant intergroup differences.
Conclusions
Measured PCA primarily reduces systematic bias rather than improving absolute accuracy. EVO toric calculations with measured PCA, especially using IOL Master 700, provide optimal trueness, whereas EVO PPCA offers high precision when measured PCA is unavailable.