Table 1. Demographic, topographic and tear film characteristics of the control and the keratoconus groups.

	Control	Keratoconus	P
Age (years)	30.2 ± 5.3	28.9 ± 6.3	0.55
Gender (male/female)	12 / 8	10 / 9	0.89
Keratometry steep axis (D)	43.9 ± 1.5	49.0 ± 5.7	<0.001
Keratometry flat axis (D)	43.1 ± 1.4	45.8 ± 5.3	<0.001
Thinnest corneal thickness (μm)	551.7 ± 13.9	422.4 ± 77.9	<0.001
Schirmer I test	13.2 ± 2.0	5.3 ± 2.2	<0.001
NI-BUT (s)	10.7 ± 3.8	9.8 ± 4.8	0.31
OSDI score	8.1 ± 2.3	26.8 ± 15.8	<0.001

Data are mean ± SD values in the control (n = 20) and in the keratoconus groups (n = 19). Note: P: Mann–Whitney U test.