Comparison of the Barrett Toric Calculator Using Measured and Predicted Posterior Corneal Astigmatism, the Kane and Abulafia-Koch Calculators.

The measured posterior corneal curvature in the Barrett calculator yielded comparable outcomes to its prediction by the Barrett and AK formulas. The Kane calculator showed a slight against-the-rule prediction error compared with the other methods, resulting in a small higher median absolute error with marginal clinical importance.