Table 3. Multivariate regression analyses to estimate the changing trend of prevalence of myopia, mean Spherical Equivalent Refraction (SER) and astigmatism with years of test.

Exposure	Year	Non-adjusted, (95% CI)	P value	Model I, (95% CI)	P value	Model II, (95% CI)	P value
Myopia prevalence	2014	Reference		Reference		Reference
	2016	1.26 (0.87, 1.84)	0.22	1.28 (0.88, 1.87)	0.19	1.28 (0.88, 1.87)	0.19
	2018	1.23 (0.85, 1.79)	0.28	1.22 (0.84, 1.77)	0.30	1.22 (0.84, 1.78)	0.29
Mean SER	2014	Reference		Reference		Reference
	2016	-0.27 (-0.34, -0.20)	< 0.0001	-0.27 (-0.34, -0.21)	< 0.0001	-0.27 (-0.345, -0.21)	< 0.0001
	2018	-0.32 (-0.39, -0.26)	< 0.0001	-0.32 (-0.38, -0.25)	< 0.0001	-0.31 (-0.38, -0.25)	< 0.0001
Mean astigmatism	2014	Reference		Reference		Reference
	2016	0.03 (0, 0.06)	0.11	0.03 (0, 0.06)	0.11	0.03 (0, 0.06)	0.12
	2018	0 (-0.03, 0.03)	0.93	0 (-0.03,0.03)	0.92	0 (-0.03, 0.03)	0.93

Model I is adjusted for age; Model II is adjusted for age and sex.