Table 4 Multivariate analyses for factors associated with astigmatism ≥1.5 diopters (N = 4801)

Grade

< 0.0001

0.65

 Kindergarten

Reference

Reference

 Grade 1

1.08 (0.63, 1.87)

1.13 (0.64, 2.00)

 Grade 2

0.94 (0.54, 1.64)

0.91 (0.51, 1.62)

 Grade 3

1.09 (0.64, 1.85)

0.96 (0.55, 1.68)

 Grade 4

1.03 (0.60, 1.77)

0.94 (0.53, 1.68)

 Grade 5

1.55 (0.94, 2.56)

1.05 (0.60, 1.81)

 Grade 6

2.16 (1.35, 3.55)

1.26 (0.74, 2.15)

 Grade 7

2.22 (1.38, 3.55)

1.16 (0.67, 1.95)

 Grade 8

2.37 (1.48, 3.81)

1.07 (0.61, 1.79)

 Grade 9

3.06 (1.92, 4.85)

1.26 (0.73, 2.10)

 Grade 10

4.06 (2.60, 6.35)

1.41 (0.82, 2.31)

 Grade 11

3.55 (2.26, 5.59)

1.15 (0.69, 1.96)

 Grade 12

2.98 (1.89, 4.69)

0.90 (0.74, 1.07)

Gender

< 0.0001

< 0.0001

 Male

1.50 (1.27, 1.78)

1.65 (1.39,1.98)

 Female

Reference

Reference

School location

0.11

0.18

 Urban

1.15 (0.97, 1.38)

1.14 (0.94, 1.36)

 Rural

Reference

Reference

Spherical equivalent of more astigmatic eye (Diopters)

< 0.0001

  ≤ −6

20.3 (13.5, 30.6)

  > −6, ≤ −5

8.05 (5.18, 12.7)

  > −5, ≤ −4

5.48 (3.68, 8.47)

  > −4, ≤ −3

4.00 (2.69, 6.10)

  > −3, ≤ −2

2.12 (1.45, 3.42)

  > −2, ≤ −1

2.05 (1.39, 3.10)

  > −1, ≤ −0.5

1.42 (0.90, 2.24)

  > −0.5, < 0.5

Reference

  ≥ 0.5, < 1.0

2.94 (1.69, 5.12)

  ≥ 1.0

10.3 (6.16, 17.1)