an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. + `0 ?- b; _, U! z: }0 ~
visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. " b H$ W C8 @' i& ~! @6 w: D) ]: D( @5 p+ G
请问上面的意思是什么?相当于国内什么等级的视力?谢谢!