Table 3.

Comparison of the Mean Absolute Prediction Error (MAE), Median Numerical Error (MNE) and Percentage Eyes with Absolute Prediction Error Within 0.5 D, 0.75 D and 1.0 D Obtained with Barrett Formulas (Barrett True K/Universal II) and IA in Post-Hyperopic LVC, Post-Myopic LVC, Post-RK and Non-Refractive Surgery Eyes

Corneal Profile	No. of Eyes	Prediction Error	Barrett True K/Universal II	IA	p-value
Post-hyperopic LVC	64	MNE ± SD	0.4±0.65	0.15±0.64	0.02
		MAE ± SD	0.61 ± 0.42	0.51 ± 0.40	0.207
		% eyes with AE ≤0.5 D	47%	56%	0.289
		% eyes with AE ≤0.75 D	64%	73%	0.254
		% eyes with AE ≤1.0 D	88%	89%	0.784
Post-myopic LVC	81	MNE ± SD	−0.1±0.82	0.05±0.80	0.07
		MAE ± SD	0.54 ± 0.62	0.57 ± 0.57	0.767
		% eyes with AE ≤0.5 D	68%	54%	0.077
		% eyes with AE ≤0.75 D	77%	75%	0.854
		% eyes with AE ≤1.0 D	83%	83%	1.000
Post-RK	25	MNE ± SD	0.2±0.88	0.52±0.96	0.2
		MAE ± SD	0.71 ± 0.68	0.89 ± 0.76	0.372
		% eyes with AE ≤0.5 D	52%	36%	0.257
		% eyes with AE ≤0.75 D	64%	56%	0.564
		% eyes with AE ≤1.0 D	80%	68%	0.337
Non-refractive surgery	103	MNE ± SD	0.06±0.86	0.03±0.77	0.69
		MAE ± SD	0.54 ± 0.69	0.50 ± 0.60	0.675
		% eyes with AE ≤0.5 D	67%	66%	0.883
		% eyes with AE ≤0.75 D	82%	78%	0.490
		% eyes with AE ≤1.0 D	89%	84%	0.304

Abbreviations: MAE, mean absolute error; MNE, median numerical error; AE, absolute error; SD, standard deviation; LVC, laser vision correction; RK, radial keratotomy; IA, intraoperative aberrometry; D, diopter.