Total corneal astigmatism values for toric intraocular lens power calculation: Devices comparison

Purpose: To compared the prediction error of three toric intraocular lens calculators including total cornea astigmatism mode of the Bausch and Lomb enVista toric calculator, Barrett toric calculator, and Panacea toric intraocular lens calculator. Methods: Thirty-six patients were included in this study who underwent cataract surgery on their 48 individual eyes by implantation of a toric Intraocular Lens (IOL). The actual residual astigmatism was compared to the predicted errors of the enVista toric calculator, the Panacea toric intraocular lens calculator, the Barrett toric calculator, using total cornea astigmatism mode. Prediction error was calculated using vector subtraction of predicted post-op astigmatism in each calculator from an actual refractive outcome. Results: The mean +/- standard deviation (SD) of patients' ages was 69.97 +/- 10.65 (ranging from 28 to 85 years). This study was completed on 26 patient right eyes (54.2%), and 22 left eyes (45.8%). The mean actual residual astigmatic error was 0.98+/-0.84 diopters (D). The correlation between actual postoperative astigmatism and the Panacea, Barrett and enVista toric astigmatism predictions were -0.065 (p = 0.659), 0.088 (p = 0.550), and -0.170 (p = 0.247). Conclusion: The Bausch and Lomb enVista toric calculator, Barrett toric calculator, and the Panacea toric intraocular lens calculator using total cornea astigmatism mode, are not significantly different in predicting the residual astigmatic outcome after implanting toric IOLs in cataract surgery; however, the Barrett toric calculator formula seems to predict postoperative astigmatism better than the other two formulas.