PREDICTION OF RESIDUAL ASTIGMATISM USING INTRAOPERATIVE WAVEFRONT ABERROMETRY VERSUS MULTIPLE TORIC IOL CALCULATORS

Published 2022 - 26th ESCRS Winter Meeting

Reference: FP37 | Type: Abstracts | DOI: 10.82333/c30q-2s03

Authors: Telmo Cortinhal* ¹ , Jorge Simão ² , Miguel Raimundo ³ , Joaquim Murta ⁴

¹Ophthalmology Department,Centro Hospitalar e Universitário de Coimbra,Coimbra,Portugal, ²Ophthalmology Department,Centro Hospitalar e Universitário de Coimbra,Coimbra,Portugal;Faculty of Medicine,University of Coimbra (FMUC),Coimbra,Portugal;Clinical Academic Center of Coimbra,(CACC),Coimbra,Portugal, ³Ophthalmology Department,Centro Hospitalar e Universitário de Coimbra ,Coimbra,Portugal;Unidade de Oftalmologia de Coimbra ,(UOC),Coimbra,Portugal;Faculty of Medicine,University of Coimbra (FMUC),Coimbra,Portugal;Clinical Academic Center of Coimbra,(CACC),Coimbra,Portugal, ⁴Ophthalmology Department,Centro Hospitalar e Universitário de Coimbra,Coimbra,Portugal;Faculty of Medicine,University of Coimbra (FMUC),Coimbra,Portugal;Unidade de Oftalmologia de Coimbra,(UOC),Coimbra,Portugal;Clinical Academic Center of Coimbra,(CACC),Coimbra,Portugal

Purpose

The Barrett Toric IOL calculator offers excellent performance by including estimation of posterior corneal astigmatism and effective lens position. The option of including measured posterior corneal astigmatism is also available. Recently, the Kane Toric formula was introduced. Intraoperative Wavefront Aberrometry (IWA) is an alternative method for intraoperative IOL cylindrical power selection and axis refinement. In this study we compared the prediction of residual astigmatism by each of these methods.

Setting

Ophthalmology Department, Centro Hospitalar e Universitário de Coimbra - CHUC, Coimbra, Portugal. Unidade de Oftalmologia de Coimbra (UOC), Coimbra, Portugal.

Methods

Prospective study with 60 eyes (60 subjects) implanted with a toric IOL (SN6ATx, Alcon) using IWA (ORA, Alcon) for intraoperative toric power selection and residual astigmatism prediction. Residual astigmatism for the same toric IOL power was back-simulated using the Barrett Toric calculator (with estimated (ePCA) and measured (mPCA) posterior corneal astigmatism), and the Kane Toric formula, using Oculus Pentacam keratometry data. Each suggested toric power by the calculator was noted. Subjective refraction was obtained 3 months postoperatively. The postoperative refractive astigmatism prediction error in the spectacle plane was evaluated by the centroid and the mean absolute error for each method.

Results

The centroid prediction error was 0.15D@175±0.52 for Barrett ePCA, 0.15D@174±0.54 for Barret mPCA, 0.22D@164±0.62 for IWA and 0.24D@179±0.54 for Kane. The Barrett ePCA showed the highest proportion of eyes with a prediction error within 0.50D, 0.75D and 1D with 62%, 90% and 93% (no improvement with mPCA), followed by IWA (50%, 75%, 92%) and Kane (50%, 80%, 92%). The chosen IOL cylindrical power (T) using IWA differed from the suggested IOL cylindrical power using the Barrett ePCA in 35/60 eyes (58%) and from the Kane in 44/60 eyes (57%), with tendency lower T values using IWA compared to the Barrett.

Conclusion

The Barrett Toric calculator had the lowest centroid and mean absolute prediction error. Measured posterior corneal astigmatism did not further enhance these predictions. The IWA device performed slightly better than the Kane Toric formula.