an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. ; @( J7 k2 }+ S5 f3 B' ~5 Z7 ~7 B1 D
visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. 9 T4 _8 m6 e. |; J: k
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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!