Official ESCRS | European Society of Cataract & Refractive Surgeons


Comparing intraoperative wavefront aberrometry and established formulas for IOL power calculation after excimer laser vision correction

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Session Details

Session Title: Toric IOLs & Lens Power Calculations

Session Date/Time: Sunday 15/09/2019 | 08:00-10:00

Paper Time: 09:38

Venue: Free Paper Forum: Podium 3

First Author: : J.Bernardes PORTUGAL

Co Author(s): :    M. Raimundo   A. Rosa   M. Quadrado   J. Neto-Murta                    

Abstract Details


To comparatively evaluate the accuracy of intraoperative wavefront aberrometry (IWA) and commonly established formulas for IOL power calculation in eyes previously submitted to myopic and hyperopic excimer laser vision correction (ELVC).


Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra - CHUC, Coimbra, Portugal. Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal. Unidade de Oftalmologia de Coimbra (UOC) - IDEALMED, Coimbra, Portugal.


Retrospective study including eyes with a history of ELVC submitted to cataract surgery aided by IWA (ORATM, Alcon). All patients underwent optical biometry (Carl Zeiss IOLMaster 500) and the post-operative spherical equivalent for the implanted IOL was estimated using the Barret True K No History, Haigis-L, Shammas and a combined average from the ASCRS website of these formulas, as well as, when historical data was available, the Barret True K, Masket and Modified-Masket formulas. Outcomes included themedian absolute prediction error (MedAE) and the proportion of eyes within 0.25, 0.50 and 1.00 diopters (D) of this prediction.


Twenty-nine eyes had previous myopic ELVC and seven eyes had hyperopic ELVC. For the myopic ELVC group, without historical data (n=29 eyes), IWA yielded the lowest MedAE (0.40D), followed by the Average (MedAE 0.48D). When considering eyes where historical data was available (n=18 eyes), the Barrett True K yielded the lowest MedAE (0.29D). In previous hyperopic ELVC, without historical data (n=7 eyes), the Haigis-L yielded the lowest MedAE (0.12D), followed by the Shammas (0.14D). When history was available (n=5 eyes), the Modified Masket had the lowest MedAE (0.08D). IWA (both no history and history) has a MedAE of 0.20D.


In the absence of historical data regarding previous myopic ELVC, IWA yielded the lowest MedAE in our cohort, while when historical data was available, the history-derived Barrett True K formula had the lowest MedAE, immediately followed by IWA. In previous hyperopic ELVC, the lowest MedAE was found in the Haigis-L formula (no history) or the Modified Masket formula (historical data). In both myopic and hyperopic ELVC, history-based formulas should always be used when such data is available to further refine IOL choice.

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