Research Article

Comparison of Predictability Using Barrett Universal II and SRK/T Formulas according to Keratometry

Table 2

The refractive error of the targeted refraction using the Barrett Universal II and the SRK/T formulas.

KeratometryNumber of eyesRefractive errorBarrett Universal IISRK/T value

Entire335Prediction error (D)0.04 ± 0.42 (−1.37 to 1.32)−0.10 ± 0.53 (−2.75 to 1.19)<0.001
Absolute error (D)0.33 ± 0.27 (0.00 to 1.37)0.38 ± 0.38 (0.00 to 2.75)0.006
Median absolute error (D)0.250.30

Flat K group69Prediction error (D)0.15 ± 0.42 (−0.65 to 1.32)0.27 ± 0.40 (−0.63 to 1.19)<0.001
Absolute error (D)0.35 ± 0.27 (0.01 to 1.32)0.37 ± 0.30 (0.00 to 1.19)0.334
Median absolute error (D)0.290.32

Normal K group180Prediction error (D)−0.02 ± 0.39 (−1.08 to 1.06)−0.05 ± 0.39 (−1.15 to 1.09)0.138
Absolute error (D)0.29 ± 0.24 (0.00 to 1.08)0.30 ± 0.25 (0.00 to 1.08)0.925
Median absolute error (D)0.230.23

Steep K group86Prediction error (D)0.08 ± 0.49 (−1.37 to 1.26)−0.49 ± 0.63 (−2.75 to 0.66)<0.001
Absolute error (D)0.38 ± 0.31 (0.01 to 1.37)0.57 ± 0.56 (0.00 to 2.75)0.003
Median absolute error (D)0.270.37

K = keratometric readings; D = diopter.