Table 2

Changes in ocular parameters and outdoor time among different puberty development groups (mean (SD))

Puberty development groups	AL (mm)			SE (D)			Outdoor time (hours)
Puberty development groups	Baseline	Follow-up	Changes	Baseline	Follow-up	Changes	Outdoor time (hours)
Menarche or first spermatorrhoea occurrence
PND (n=403)	23.87 (1.10)	24.51 (1.21)	0.63 (0.34)*	−0.62 (1.76)	−1.56 (2.08)	−1.06 (0.66)*	2.01 (1.18)
ND (n=143)	24.24 (0.96)	24.79 (1.00)	0.55 (0.30)*	−1.69 (1.98)	−2.86 (2.16)	−1.01 (0.59)*	2.30 (1.29)
BD (n=83)	24.59 (1.21)	25.15 (1.24)	0.56 (0.32)*	−2.32 (2.35)	−3.73 (2.44)	−1.18 (0.72)*	1.85 (1.09)
P value†	<0.001	<0.001	0.017	<0.001	<0.001	0.348	0.015
Boys’ first spermatorrhoea
PND (n=266)	24.18 (1.03)	24.81 (1.15)	0.63 (0.34)*	−0.83 (1.77)	−1.75 (2.14)	−1.03 (0.65)*	1.98 (1.19)
ND (n=40)	24.72 (0.97)	25.27 (1.07)	0.54 (0.33)*	−1.68 (1.83)	−2.93 (2.00)	−0.96 (0.59)*	2.45 (1.28)
BD (n=36)	25.28 (1.11)	25.89 (1.10)	0.61 (0.34)*	−3.12 (2.28)	−4.35 (2.44)	−1.27 (0.81)*	1.92 (0.94)
P value†	<0.001	<0.001	0.344	<0.001	<0.001	0.187	0.072
Girls’ menarche
PND (n=137)	23.26 (0.98)	23.93 (1.10)	0.65 (0.33)*	−0.20 (1.67)	−1.19 (1.90)	−1.12 (0.69)*	2.06 (1.16)
ND (n=103)	24.05 (0.89)	24.61 (0.90)	0.56 (0.29)*	−1.70 (2.04)	−2.82 (2.24)	−1.03 (0.59)*	2.24 (1.30)
BD (n=47)	24.07 (1.01)	24.60 (1.06)	0.53 (0.31)*	−1.70 (2.24)	−3.11 (2.31)	−1.08 (0.60)*	1.80 (1.19)
P value†	<0.001	<0.001	0.024	<0.001	<0.001	0.712	0.122

*P <0.01, compared between baseline and follow-up within the group using paired t-test.
†Statistical significance was tested using variance analysis.
AL, axial length; BD, baseline developed; ND, newly developed; PND, persistent non-developed; SE, spherical equivalent.