Age-Related Change of Axial Length, Spherical Equivalent, and Prevalence of Myopia and High Myopia in School-Age Children in Shanghai: 2014–2018

Table 2

Comparisons of parameters of children between 2014 and 2018.

	All			Primary school			Junior high school			Senior high school
	2014	2018		2014	2018		2014	2018		2014	2018
Age (years)	12.2 ± 3.7	11.4 ± 3.7	<0.001	8.4 ± 1.5	8.1 ± 1.5	<0.001	13.0 ± 1.4	12.7 ± 1.3	<0.001	16.6 ± 1.0	16.5 ± 1.0	0.049
AL (mm)	23.95 ± 1.37	23.85 ± 1.33	0.003	23.11 ± 0.88	23.13 ± 0.89	0.531	24.01 ± 1.20	24.04 ± 1.17	0.671	25.03 ± 1.27	25.02 ± 1.23	0.855
SE (D)	−1.84 ± 2.27	−1.62 ± 2.31	<0.001	−0.41 ± 1.19	−0.37 ± 1.21	0.369	−1.71 ± 1.73	−1.82 ± 2.12	0.243	−3.92 ± 2.25	−3.74 ± 2.40	0.092
Myopia	63.3%	57.8%	<0.001	34.3%	33.1%	0.510	51.9%	69.2%	<0.001	93.9%	93.0%	0.519
High myopia	6.7%	6.1%	0.155^a	0.3%	0.4%	1.000	2.7%	4.8%	0.030	19.4%	17.7%	0.378
	8.5%	7.1%	0.013^b	0.3%	0.2%	0.725	5.8%	6.3%	0.685	23.2%	20.9%	0.510
Time outdoors (hour)	64.1 ± 49.8	61.3 ± 45.5	0.018	67.1 ± 40.4	55.7 ± 33.7	<0.001	72.2 ± 63.8	77.7 ± 58.0	0.065	52.9 ± 45.2	57.0 ± 47.8	0.057
Time of study (hour)	157.4 ± 89.5	180.2 ± 111.4	<0.001	110.8 ± 60.0	137.6 ± 61.9	<0.001	135.6 ± 73.7	162.5 ± 88.9	<0.001	238.6 ± 80.9	274.6 ± 140.7	<0.001

AL, axial length; SE, spherical equivalent. ^aHigh myopia was defined as SE ≤ −6.00 D; ^bhigh myopia was defined as AL ＞ 26 mm.; .