Reduced Refractive Predictability In Non-Emmetropic Targets: Comparative Analysis Of Modern Iol Formulae In Monovision
Published 2026 - 44th Congress of the ESCRS
Reference: FP13.14 | Type: Free paper | DOI: 10.82333/ham9-aq68
Authors: Ms Marina Ramos Gonçalves* 1 , A/Prof. André Messias 1
1Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery (ROO) of the Medical School of Ribeirão Preto (FMRP) at the University of São Paulo,Medical School of Ribeirão Preto (FMRP) at the University of São Paulo,Ribeirão Preto,Brazil
Purpose
To evaluate refractive predictability of contemporary intraocular lens (IOL) formulae in non-emmetropic targets and to determine whether refractive strategy independently influences prediction error.
Setting
Retrospective single-center study at a tertiary ophthalmic referral center.
Methods
Thirty-eight eyes of 19 patients undergoing cataract surgery with planned monovision were analyzed. Biometric data were processed using custom software and entered into the ESCRS calculator. Formulae evaluated included Barrett, Cooke K6, EVO, Hill-RBF, Hoffer QST, Kane, Pearl DGS and Haigis. Predicted refraction was compared with postoperative refraction at 4–12 weeks. Signed prediction error (PE), absolute prediction error (ABS PE) and root mean square error were calculated. Repeated-measures ANOVA with Tukey HSD compared formulae and refractive targets (far vs near). A linear mixed-effects model assessed associations between biometric parameters, refractive strategy and ABS PE.
Results
Absolute prediction error was significantly greater in near targets than in far targets (0.397 D vs 0.194 D). Kane, Hill-RBF, Pearl DGS and Cooke K6 demonstrated superior overall performance, particularly for emmetropic targets. Hoffer QST and Haigis showed larger errors in near eyes. In multivariable analysis, greater preoperative astigmatism was consistently associated with myopic shift in signed error. Refractive target (far vs near) remained an independent determinant of absolute prediction error after adjustment for biometric variables. Approximately 40–50% of refractive variability was attributable to inter-individual factors not captured by measured biometrics.
Conclusions
Refractive predictability is significantly reduced in non-emmetropic targets compared with emmetropic targets, independent of conventional biometric parameters. Target strategy independently influences absolute prediction error, and preoperative astigmatism contributes to systematic bias. Target-specific considerations should be incorporated into IOL power calculation, particularly in monovision planning.