an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. 9 J8 f$ I$ S; W
visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. ' c* O. m* Q8 W. f/ Y
; n; r" ^6 D& r- ?" A3 e8 B
请问上面的意思是什么?相当于国内什么等级的视力?谢谢!