Table 3.

Refractive prediction error, mean absolute error and median absolute error produced by each formula in PEX and control groups after adjusting mean RPE to zero.

	SRK/T	Barrett Universal II	Hill-RBF	P value (Friedman test)
PEX n = 42
RPE ± SD, D (range)	0.000 ± 0.644 (− 1.761, + 1.389)	0.000 ± 0.641 (− 1.812, + 1.648)	0.000 ± 0.643 (− 1.783, + 1.687)
MAE ± SD, D	0.498 ± 0.401	0.479 ± 0.420,	0.479 ± 0.420
MedAE, D	0.460	0.385	0.400	0.636
Control n = 38
RPE ± SD, D (range)	0.000 ± 0.381 (− 0.783, + 1.052)	0.000 ± 0.371 (− 0.783, + 1.152)	0.000 ± 0.379 (− 0.758, + 1.038)
MAE ± SD, D	0.288 ± 0.244	0.286 ± 0.232	0.292 ± 0.237
MedAE, D	0.213	0.219	0.243	0.442

PEX: pseudoexfoliation syndrome; RPE: refractive prediction error; SD: standard deviation; D: diopter; MAE: mean absolute error; MedAE: median absolute error.