an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. ' J7 e, U$ C) v2 V7 O
visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. " q, e, O' a5 {* o# a2 Y/ `' E4 V" z# 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!