an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. ! O: M, r9 b6 @6 i; }
visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. ! \& V& F- W8 M
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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!