Table 2.

 Group Mean Values of α and β Parameters for the Three Study Groups

		Scale Parameter α			Shape Parameter β
		Group Mean	Post Hoc Test		Group Mean	Post Hoc Test
	Group	± SD (range), a.u.		P	± SD (range), a.u.		P
Mean map value	Control	39 ± 3 (34–47)	C vs. S	0.037	4.1 ± 0.5 (3.5–5.8)	C vs. S	1.00
	Subclinical	43 ± 4 (36–51)	S vs. KC	0.020	4.1 ± 0.6 (2.3–5.5)	S vs. KC	1.00
	Keratoconus	47 ± 5 (35–59)	KC vs. C	<0.001	3.9 ± 0.4 (3.1–4.7)	KC vs. C	0.53
Mean value in Q4	Control	41 ± 2 (38–47)	C vs. S	<0.001	4.3 ± 0.4 (3.8–5.8)	C vs. S	1.00
	Subclinical	50 ± 4 (44–53)	S vs. KC	1.00	4.1 ± 0.6 (2.4–5.5)	S vs. KC	0.010
	Keratoconus	50 ± 1 (44–59)	KC vs. C	<0.001	4.7 ± 0.7 (3.5–6.8)	KC vs. C	0.097

The group mean of the variable used for the ROC analysis (i.e., values in the fourth quartile [Q4] in each corneal map) is also included. Comparisons within groups were studied using one-way analysis of variance with Bonferroni adjustment for multiple comparisons. The corresponding post hoc test (multiple comparisons) is shown. Numbers in bold indicate a statistically significant difference. C, control; S, subclinical keratoconus; KC, clinical keratoconus.