Table 3.

Corneal aberrations parameters and their comparisons between groups.

Parameters mean ± SD	Normal N = 25	Suspect N = 41	Mild KC N = 40	Moderate KC N = 71	Severe KC N = 48
Corneal asphericity (Q)	0.2 ± 0.1	0.3 ± 0.3	0.5 ± 0.4	0.9 ± 0.6	1.7 ± 0.8
Total RMS	0.4 ± 0.2	0.5 ± 0.4	0.7 ± 0.6	1.2 ± 0.7	3.4 ± 2.5
RMS Spherical aberration	0.1 ± 0.1	0.1 ± 0.1	0.2 ± 0.2	0.2 ± 0.2	0.7 ± 0.7
RMS coma	0.2 ± 0.1	0.3 ± 0.2	0.5 ± 0.6	0.9 ± 0.7	2.2 ± 1.5
RMS Astigmatism	0.1 ± 0.7	1.6 ± 1.4	2.3 ± 2.6	4.1 ± 3.4	6.6 ± 5.6
BCVf	0.2 ± 0.2	0.8 ± 0.8	1.1 ± 0.9	2.3 ± 1.6	5.4 ± 3.0
BCVb	0.1 ± 0.2	0.9 ± 0.8	1.3 ± 1.3	2.5 ± 1.7	5.0 ± 3.2

RMS: Root Mean Square, BCV_f: Baiocchi Calossi Versaci front index, BCV_b: Baiocchi Calossi Versaci back index, KC:Keratoconus.