Table 2. Mean preoperative and postoperative RMS values and Zernike aberrations (µm) in the total cornea over a 6.0 mm diameter central area in 3 groups.

Parameters	12 o'clock incision group			9 o'clock clear corneal incisions			BENT incision group
	Preop.	Postop.	P	Preop.	Postop.	P	Preop.	Postop.	P
Total RMS	2.212±0.877	1.956±0.939	0.219	2.640±0.918	2.424±1.065	0.284	2.123±0.844	1.945±0.690	0.165
tLOA	2.152±0.868	1.868±0.955	0.267	2.540±0.900	2.263±1.052	0.167	2.023±0.823	1.825±0.688	0.100
tHOA	0.723±0.371	0.483±0.177	0.000	0.697±0.258	0.758±0.315	0.175	0.612±0.283	0.642±0.210	0.639
Z (3, -3)	-0.019±0.101	0.026±0.150	0.214	-0.025±0.109	-0.077±0.242	0.142	-0.009±0.256	-0.055±0.164	0.398
Z (3, -1)	-0. 000±0.254	-0.086±0.236	0.214	0.168±0.230	0.190±0.327	0.637	0.186±0.242	0.092±0.247	0.010
Z (3,1)	0.029±0.192	0.025±0.174	0.936	0.103±0.239	0.129±0.218	0.445	0.084±0.156	0.138±0.177	0.057
Z (3,3)	-0.008±0.067	-0.030±0.100	0.084	0.010±0.121	0.044±0.164	0.249	-0.013±0.089	0.005±0.165	0.550
Z(4, -4)	0.001±0.083	-0.079±0.269	0.159	0.010±0.151	-0.070±0.253	0.116	0.063±0.216	-0.027±0.211	0.129
Z (4, -2)	-0.020±0.080	0.027±0.082	0.056	0.009±0.090	0.028±0.097	0.315	0.000±0.083	0.048±0.111	0.062
Z (4, 0)	0.251±0.139	0.239±0.143	0.730	0.371±0.149	0.328±0.154	0.111	0.334±0.127	0.243±0.092	0.000
Z (4, 2)	-0.018±0.087	0.023±0.112	0.035	-0.039±0.150	-0.078±0.123	0.229	-0.045±0.104	-0.058±0.113	0.466
Z (4,4)	-0.056±0.105	-0.277±0.247	0.000	-0.006±0.242	-0.209±0.256	0.000	-0.048±0.121	0.051±0.168	0.024
Coma	0.047±0.307	-0.031±0.260	0.019	0.187±0.587	0.199±0.777	0.841	0.270±0.287	0.230±0.290	0.316
Trefoil	-0.006±0.131	-0.083±0.489	0.321	0.005±0.200	-0.017±0.279	0.638	-0.022±0.239	-0.050±0.272	0.661
Tetrafoil	-0.057±0.125	-0.358±0.302	0.000	0.016±0.285	-0.267±0.373	0.000	0.018±0.282	0.024±0.287	0.939
Secondary astigmatism	-0.035±0.117	0.048±0.128	0.004	-0.032±0.175	-0.052±0.166	0.579	-0.042±0.133	-0.010±0.147	0.264

RMS: Root mean square; tLOA: Total low order aberration; tHOA: Total high order aberration; Z: Zernik; Coma: Z₃⁻¹ and Z₃¹; Trefoil: Z₃⁻³ and Z₃³; Tetrafoil: Z₄⁻⁴ and Z₄⁴; Secondary astigmatism: Z₄⁻² and Z₄². The terms of coma, trefoil, tetrafoli and secondary astigmatism indicate the RMS values of the 2 Zernike aberration, P<0.05; P<0.01; P<0.001.