Table 4.

Comparison of the repeatability (within subject SD, in μm) with the between-subject variability (SD, in μm) for higher-order aberrations measured with the Zywave for 7mm pupil. The final column shows the ratio of these values, a smaller value representing better repeatability.

Zernike coeff.	Within-subject SD (from Table 3)	Between-subject SD	Ratio
C20	0.233	4.985	0.047
C2−2	0.064	0.787	0.081
C2+2	0.102	1.467	0.070
C3−1	0.113	0.333	0.338
C3+1	0.059	0.240	0.246
C3−3	0.053	0.197	0.268
C3+3	0.051	0.193	0.263
C40	0.043	0.304	0.143
C4+2	0.046	0.114	0.402
C4−2	0.034	0.065	0.524
C4+4	0.051	0.093	0.546
C4−4	0.054	0.060	0.893
C5+1	0.025	0.029	0.850
C5−1	0.029	0.047	0.606
C5+3	0.028	0.036	0.774
C5−3	0.031	0.031	0.988
C5+5	0.034	0.050	0.684
C5−5	0.038	0.031	1.221