Table 4 Changes in axial length during the 2-year treatment of subjects with different degrees of myopia between the ortho-k group (65 subjects) and spectacle group (63 subjects)

Low myopia

Ortho-k

0.19 ± 0.17

0.18 ± 0.14

0.37 ± 0.28

Control

0.40 ± 0.18

0.32 ± 0.19

0.72 ± 0.28

t

−3.80

−2.64

−3.97

P

0.001

0.012

<0.001

Moderate myopia

Ortho-k

0.14 ± 0.18

0.18 ± 0.16

0.32 ± 0.31

Control

0.45 ± 0.22

0.34 ± 0.30

0.79 ± 0.39

t

−5.09

−2.24

−4.40

P

<0.001

0.030

<0.001

High myopia

Ortho-k

0.16 ± 0.18

0.18 ± 0.15

0.33 ± 0.30

Control

0.34 ± 0.22

0.27 ± 0.21

0.61 ± 0.36

t

−3.05

−1.651

−2.814

P

0.004

0.107

0.007

Total

Ortho-k

0.16 ± 0.17

0.18 ± 0.15

0.34 ± 0.29

Control

0.39 ± 0.21

0.31 ± 0.24

0.70 ± 0.35

t

−6.87

−3.699

−6.408

P

<0.001

<0.001

<0.001