Table 3.

Multivariate analyses for factors associated with cylinder power among all students (N = 4801)

		Multivariate Model 1: without including spherical equivalent*		Multivariate Model 2: including spherical equivalent§
Characteristics	N	Mean Cylinder in diopter (SE)	P-value	Mean Cylinder in diopter (SE)	P-value
Grade			< 0.0001		0.54
Kindergarten	381	0.66 (0.04)		0.91 (0.04)
Grade 1	331	0.65 (0.04)		0.92 (0.04)
Grade 2	366	0.70 (0.04)		0.94 (0.04)
Grade 3	371	0.72 (0.04)		0.94 (0.04)
Grade 4	367	0.71 (0.04)		0.93 (0.04)
Grade 5	376	0.79 (0.04)		0.94 (0.04)
Grade 6	368	0.90 (0.04)		1.01 (0.04)
Grade 7	376	0.90 (0.04)		0.98 (0.04)
Grade 8	360	0.93 (0.04)		0.97 (0.04)
Grade 9	346	1.01 90.04)		1.01 (0.04)
Grade 10	383	1.09 (0.04)		1.02 (0.04)
Grade 11	373	1.06 (0.04)		0.98 (0.04)
Grade 12	403	1.04 (0.04)		0.93 (0.04)
Gender			< 0.0001		< 0.0001
Male	2647	0.91 (0.01)		1.01 (0.02)
Female	2154	0.81 (0.02)		0.91 (0.02)
School location			0.10		0.18
Urban	2691	0.88 (0.02)		0.97 (0.02)
Rural	2110	0.84 (0.01)		0.95 (0.02)
Spherical equivalent of more astigmatic eye (Diopters)					< 0.0001
≤ −6	351			1.64 (0.04)
> −6, ≤ −5	267			1.21 (0.04)
> −5, ≤ −4	414			1.04 (0.04)
> −4, ≤ −3	510			0.94 (0.03)
> −3, ≤ −2	584			0.77 (0.03)
> −2, ≤ −1	768			0.74 (0.03)
> −1, ≤ −0.5	557			0.68 (0.03)
> −0.5, < 0.5	1076			0.63 (0.02)
≥ 0.5, < 1.0	171			0.71 (0.06)
≥ 1.0	103			1.23 (0.07)

*Multivariate model 1 included grade, gender and school location

^§Multivariate model 2 included grade, gender, school location and spherical equivalent