an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. : L) F! d, q* S' x) l
visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. " E* A0 o8 _2 j) m" L% S! g4 M4 ~1 d# Q
请问上面的意思是什么?相当于国内什么等级的视力?谢谢!