an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. 0 u9 ^9 q* Z) {5 j- E1 } t/ x- W
visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. 3 M# Q2 s8 m1 q3 r1 F' Y( ~
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请问上面的意思是什么?相当于国内什么等级的视力?谢谢!