Table 2.

Preoperative HOAs.

Higher-Order Aberration	PRK (n = 100)	LASIK (n = 100)	P Value
Root mean square (µm)
Total HOA			.9
Mean ± SD	0.16 ± 0.12	0.16 ± 0.15
Range	0.05 to 0.95	0.05 to 0.90
Coma			.5
Mean ± SD	0.06 ± 0.04	0.05 ± 0.03
Range	0.01 to 0.38	0.01 to 0.13
Trefoil			.8
Mean ± SD	0.11 ± 0.07	0.10 ± 0.06
Range	0.02 to 0.44	0.01 to 0.34
Tetrafoil			.5
Mean ± SD	0.05 ± 0.10	0.06 ± 0.15
Range	0.00 to 0.86	0.00 to 0.82
Spherical aberration			.7
Mean ± SD	0.03 ± 0.03	0.03 ± 0.04
Range	0.00 to 0.16	0.00 to 0.32
Coefficient (µm)
Coma			.6
Mean ± SD	−0.01 ± 0.05	−0.01 ± 0.06
Range	−0.12 to 0.16	−0.21 to 0.16
Trefoil			.9
Mean ± SD	−0.03 ± 0.16	−0.03 ± 0.12
Range	−0.97 to 0.29	−0.38 to 0.40
Tetrafoil			.5
Mean ± SD	−0.01 ± 0.18	−0.002 ± 0.11
Range	−0.61 to 0.17	−0.43 to 0.66
Spherical aberration			.6
Mean ± SD	0.01 ± 0.04	0.01 ± 0.05
Range	−0.16 to 0.10	−0.34 to 0.06

Coefficient = grouped higher-order aberration coefficient values; HOA= higher-order aberrations; LASIK = laser in situ keratomileusis; PRK = photorefractive keratectomy; RMS = root-mean-square values