Early Age of the First Myopic Spectacle Prescription, as an Indicator of Early Onset of Myopia, Is a Risk Factor for High Myopia in Adulthood

Table 3

Comparison between high myopia and non-high myopia.

Clinical parameters	High myopia (n = 91)	Non-high myopia (n = 240)	value
Age (years)	32.51 ± 4.21	33.00 ± 4.78	0.334
Sex (male)	29 (31.9%)	66 (27.5%)	0.433
Current myopia (diopters)	−7.42 ± 1.61	−2.85 ± 1.64	<0.001
Parents’ high myopia
Father	4 (4.4%)	7 (2.9%)	0.503
Mother	11 (12.1%)	9 (3.8%)	0.004
First glasses
Age (years)	11.05 ± 2.60	14.36 ± 3.76	<0.001
Age before 12 years	68 (74.7%)	48 (23.1%)	<0.001
Age before 15 years	85 (94.4%)	153 (73.9%)	<0.001
Refractive power (diopters)	−2.28 ± 0.89	−1.38 ± 0.91	<0.001
Primary school
Near work (hr/wk)	21.21 ± 16.16	18.22 ± 15.45	0.042
Indoor sports (hr/wk)	0.54 ± 1.22	1.60 ± 3.99	0.034
Outdoor sports (hr/wk)	2.92 ± 5.73	4.59 ± 7.78	0.033
After-school class attendance	37 (40.7%)	93 (38.8%)	0.751
Sport team	11 (12.1%)	35 (14.6%)	0.558
Junior high school
Near work (hr/wk)	24.23 ± 15.82	21.45 ± 16.79	0.053
Indoor sports (hr/wk)	0.49 ± 1.08	1.15 ± 3.79	0.188
Outdoor sports (hr/wk)	2.45 ± 5.11	2.81 ± 6.59	0.314
After-school class attendance	74 (81.3%)	176 (73.3%)	0.131
Sport team	6 (6.6%)	13 (5.4%)	0.681
Senior high school
Near work (hr/wk)	26.45 ± 18.01	22.52 ± 18.44	0.029
Indoor sports (hr/wk)	0.57 ± 1.47	0.81 ± 2.39	0.583
Outdoor sports (hr/wk)	1.89 ± 3.26	2.00 ± 4.69	0.767
After-school class attendance	50 (54.9%)	100 (41.7%)	0.030
Sport team	4 (4.4%)	9 (3.8%)	0.787
University
Near work (hr/wk)	29.73 ± 17.07	25.42 ± 20.04	0.007
Indoor sports (hr/wk)	0.64 ± 1.40	1.61 ± 7.85	0.766
Outdoor sports (hr/wk)	1.85 ± 4.27	1.88 ± 3.84	0.901
After-school class attendance	6 (6.6%)	14 (5.8%)	0.796
Sport team	3 (3.3%)	11 (4.6%)	0.604