Table 4 Mean arithmetic values and power vectors for total corneal refractive power at 2.0–5.0 mm rings
From: Analysis of total corneal astigmatism with a rotating Scheimpflug camera in keratoconus
2.0 mm ring | 3.0 mm ring | 4.0 mm ring | 5.0 mm ring | *p value | ||
|---|---|---|---|---|---|---|
Centered on pupil | Mean keratometry (diopter) | 47.98 ± 4.59 | 47.47 ± 3.54 | 46.86 ± 2.51 | 46.15 ± 1.91 | < 0.001 |
Mean arithmetic astigmatism (diopter) | 4.77 ± 2.28 | 4.99 ± 2.23 | 4.81 ± 2.33 | 4.07 ± 2.30 | < 0.001 | |
KP(0) (diopter) | − 2.65 ± 3.42 | − 3.23 ± 3.64 | −3.45 ± 3.51 | − 3.08 ± 3.00 | 0.001 | |
KP(45) (diopter) | 1.51 ± 2.68 | 1.18 ± 2.22 | 0.87 ± 1.95 | 0.69 ± 1.74 | 0.002 | |
Centered on apex | Mean keratometry (diopter) | 49.39 ± 5.27 | 48.42 ± 3.96 | 47.40 ± 2.70 | 46.48 ± 1.77 | < 0.001 |
Mean arithmetic astigmatism (diopter) | 5.19 ± 2.79 | 4.55 ± 2.09 | 4.04 ± 1.72 | 3.28 ± 1.55 | < 0.001 | |
KP(0) (diopter) | −2.73 ± 3.91 | −2.70 ± 3.26 | −2.58 ± 2.79 | −2.29 ± 2.25 | 0.081 | |
KP(45) (diopter) | 1.64 ± 3.09 | 1.20 ± 2.42 | 0.86 ± 2.06 | 0.65 ± 1.59 | < 0.001 | |
** p value for mean keratometry | < 0.001 | < 0.001 | < 0.001 | < 0.001 | ||
** p value for mean arithmetic astigmatism | 0.002 | 0.01 | < 0.001 | < 0.001 | ||
** p value for KP(0) | 0.66 | < 0.001 | < 0.001 | < 0.001 | ||
** p value for KP(45) | 0.041 | 0.78 | 0.57 | 0.18 | ||