Official ESCRS | European Society of Cataract & Refractive Surgeons


The accuracy of thick-lens intraocular lens power calculation based on cutting-card or calculated data for lens architecture

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Session Details

Session Title: Posterior Capsule Opacification/IOL Power Calculations

Session Date/Time: Tuesday 17/09/2019 | 14:00-16:00

Paper Time: 15:16

Venue: Free Paper Forum: Podium 2

First Author: : K.Næser DENMARK

Co Author(s): :    G. Savini                             

Abstract Details


To compare the accuracy of a thick-lens intraocular lens (IOL) power formula using manufacturers´ cutting card information (the Næser 1 formula) and calculated data from open sources (the Næser 2 formula) for IOL architecture. To compare these results to the achievements of the Barrett Universal II, Haigis, Hoffer Q, Holladay 1, and SRK/T formulas.


Setting: IRCCS – Bietti Foundation, Rome, Italy


The design was a retrospective case-series. For each IOL power formula, we retrospectively calculated the prediction error in refraction in 151 eyes following phacoemulsification with implantation of the Alcon SN60WF posterior chamber IOL. Predictions made using the different formulas were optimized in retrospect by adjusting the respective constants. The mean arithmetic error (ME), the variance, and the median absolute error (MedAE) were calculated, as well as the dependency of the arithmetic error on the axial length (AL/error).


The Næser 1 and Næser 2 formulas were identical clinically and statistically. The ME (p= 0.278 with a one-way analysis of variance) and the variances for arithmetic errors (p=0.248 with Levene´s homogeneity test) were similar for all seven formulas. A combined metric of ME, variance, MedAE, and AL/error suggested the Næser 2 formula as the most accurate, followed by the Næser 1, Barrett Universal II, Haigis, SRK/T, Hoffer Q, and Holladay 1 formulas.


The Næser thick-lens IOL power equations based on calculated and manufacturer´s IOL data provided similar accuracies and performed approximately as the best thin-lens formulas. Cutting card information is not necessary in IOL power calculation.

Financial Disclosure:


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