Polar Value Analysis of Low to Moderate Astigmatism with Wavefront-Guided Sub-Bowman Keratomileusis

Table 4

Polar value analysis of changes in anterior corneal astigmatism (ACA) and total ocular astigmatism (TOA) stratified by the magnitude of preoperative cylinder at 6 months postoperatively.

	Parameter	≤1.0 D ()	1.0 to 2.0 D ()	>2.0 D ()	value
Anterior corneal astigmatism
Preop	AKP	0.80 ± 0.63	1.75 ± 0.51	3.05 ± 0.77	<0.001
	AKP + 45	−0.06 ± 0.40	−0.12 ± 0.47	−0.25 ± 0.45	0.371
	Net astigmatism	0.80 @ −2.14°	1.75 @ −1.96°	3.06 @ −2.34°	—
Postop 6 m	AKPerror	0.07 ± 0.40	0.15 ± 0.47	0.55 ± 0.57	0.004
	AKP + 45error	0.05 ± 0.34	0.01 ± 0.39	0.21 ± 0.42	0.267
	│AKPerror│	0.33 ± 0.23	0.40 ± 0.28	0.66 ± 0.42	0.001
	Net astigmatism	0.09 @ 17.77°	0.15 @ 1.91°	0.59 @ 10.45°	—
Total ocular astigmatism
Preop	AKP	0.63 ± 0.23	1.34 ± 0.28	2.81 ± 0.74	<0.001
	AKP + 45	0.00	0.00	0.00	—
	Net astigmatism	0.63 @ 0	1.34 @ 0	2.81 @ 0	—
Postop 6 m	AKPerror	0.004 ± 0.25	0.16 ± 0.35	0.36 ± 0.72	0.007
	AKP + 45error	0.08 ± 0.24	0.002 ± 0.31	0.48 ± 0.62	<0.001
	│AKPerror│	0.19 ± 0.16	0.30 ± 0.24	0.63 ± 0.48	<0.001
	Net astigmatism	0.08 @ 43.57°	0.16 @ 0.36°	0.60 @ 26.57°	—