an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. . V2 c8 [4 ]" V2 a" L1 Z& G
visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. / o; `2 S! ` \, J
& o- h; R, V& C
请问上面的意思是什么?相当于国内什么等级的视力?谢谢!