Official ESCRS | European Society of Cataract & Refractive Surgeons


Comparison of three newer generation freely-available intraocular lens power calculation formulae across all axial lengths

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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: 15:28

Venue: Free Paper Forum: Podium 2

First Author: : Z.Khatib INDIA

Co Author(s): :    S. Haldipurkar   P. Nagvekar   H. Dahake   Y. Trivedi   A. Patel   P. Kashelkar              

Abstract Details


To evaluate the accuracy of 3 newer generation formulae (Barrett Universal II, EVO, Hill-RBF version 2) for calculation of power of 2 standard IOLs – the Acrisof IQ and Tecnis ZCB across all axial lengths.


Laxmi Eye Institute, Panvel.


206 eyes of 206 patients operated for cataract surgery with above 2 IOLs implantated over last 6 months were included in the study. Preoperative biometry measurements were obtained from LenstarLS900. By using recommended IOL constants, the mean error for each formula was calculated and compared. Then the optimized IOL constants were calculated to reduce the mean error to zero. The mean and median absolute errors were calculated for all eyes and separately for short (AL<22.5mm), medium (22.5-24.5mm) and long eyes (>24.5mm). Absolute errors were compared, as well as percentages of eyes within prediction errors of 0.25D, 0.50D, 1.00D, and 2.00D.


Mean prediction error with using recommended lens constants was significantly lower in the Barrett Universal II formula as compared to the other two formulae. However, after optimizing lens constants, there were no significant differences in the absolute errors between the 3 formulae. The formulae ranked by the mean absolute error were as follows: Barrett Universal II (0.304 D), EVO (0.317 D), Hill-RBF (0.322) D. There were no significant differences between absolute errors in the 3 formulae in each of the short, medium, and long eyes subgroups.


With proper lens constant optimization, the Barrett Universal II, EVO, and Hill-RBF 2.0 formulae were equally accurate in predicting IOL power across the entire range of axial lengths.

Financial Disclosure:


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