Table 1

Distribution of astigmatism, irregularity, and mean power in anterior and posterior corneal surface and combination of anterior and posterior corneal surface in 3 mm, 5 mm, and 7 mm diameters of 46 subjects

3 mm
Mean (SD)		5 mm
Mean (SD)		7 mm
Mean (SD)
Astigmatism (D)1.22 (1.08)0.94 (0.44)1.51 (0.91)
Anterior corneal surface
Irreg 1.16 (0.53)1.73 (0.75)2.89 (1.03)
 Mean (D) 49.30 (1.91)48.78 (1.68)47.76 (1.55)
Posterior corneal surface
Irreg 0.37 (0.18)0.52 (0.25)1.04 (0.70)
 Mean (D) 6.30 (0.21)6.16 (0.23)5.95 (0.25)
Combination of anterior and posterior corneal surface
Irreg 1.05 (0.48)1.57 (0.69)2.57 (1.00)
 Mean (D) 44.29 (1.72)43.82 (1.54)42.89 (1.39)

  • ↵Irregularity = maps represent deviation of both the mean and astigmatic curvature in adjacent small areas.

  • ↵Mean power = Gaussian power proportional to the mean curvature of the optical surface and based on physiological refractive indices.