Table 3.

Relationship between usage period of hard contact lens and corneal parameters in low- and high-Dk groups.

	Low-Dk group				High-Dk group
	Regression coefficient	Lower 95% CI	Upper 95% CI	P-value	Regression coefficient	Lower 95% CI	Upper 95% CI	P-value
ECD (cells/mm2)	−5.42	−6.88	−3.96	< 0.0001	−5.05	−6.64	−3.45	< 0.0001
CV (%)	0.21	0.15	0.27	< 0.0001	0.088	0.054	0.12	< 0.0001
6A (%)	−0.24	−0.32	−0.15	< 0.0001	−0.18	−0.23	−0.12	< 0.0001
Cell area (μm2)	0.47	0.11	0.83	< 0.0001	0.35	0.16	0.55	< 0.0001

ECD endothelial cell density; CV coefficient of variation of the cell area; 6A rate of appearance of hexagonal cells.