Clinical Ophthalmology (Jan 2022)
Comparison of Barrett and Emmetropia Verifying Optical Toric Calculators
Abstract
Seth M Pantanelli,1 Ashley Sun,1 Neal Kansara,2 Gerard Smits3 1Department of Ophthalmology, Penn State College of Medicine, Hershey, PA, USA; 2Department of Ophthalmology, Baylor College of Medicine, Houston, TX, USA; 3Computer and Statistical Consultants Incorporated, Santa Barbara, CA, USACorrespondence: Seth M PantanelliDepartment of Ophthalmology, Penn State College of Medicine, 500 University Drive, HU19, Hershey, PA, 17033-0850, USA, Tel +1 717-531-5690, Fax +1 717-531-5009, Email [email protected]: The purpose of this study was to compare the Barrett (BTC) and Emmetropia Verifying Optical (EVO) Toric Calculators’ performance with regards to prediction of residual post-operative astigmatism after cataract surgery.Methods: This was a secondary analysis of de-identified data that was collected as part of a prospective multicenter clinical trial in which 109 eyes from 109 patients were implanted with a monofocal toric intraocular lens (IOL). Post-operative biometry was used to calculate the predicted post-operative residual astigmatism for each eye using the two different calculators. The vector difference between the actual and predicted residual astigmatism was calculated.Results: The mean absolute astigmatism prediction errors were 0.59 ± 0.38 D and 0.59 ± 0.36 D for the BTC and EVO calculators, respectively (p = 0.98). The centroid of the prediction errors were 0.18 D @ 89° ± 0.68 D and 0.20 D @ 89° ± 0.66 D, respectively (p = 0.21). The proportion of eyes in which the astigmatism prediction error was ≤ 0.5 D was 50% for BTC and 46% for EVO (p = 0.28). The proportion of eyes in which the post-operative astigmatism orientation was correctly predicted as being against-the-rule, with-the-rule, or oblique was 81% for BTC and 77% for EVO (p = 0.15).Conclusion: The Barrett and Emmetropia Verifying Optical Toric Calculators had similar performance with regards to their astigmatism prediction accuracy.Keywords: Barrett, EVO, astigmatism, toric, cataract, residual astigmatism
