an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. ; G' E; j! t& h! l. P; [visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. / a2 N7 q b* {2 V# c' A# W" ^! o. j
3 \! ~/ V" T. u* m$ m2 h& ?3 {; Y
请问上面的意思是什么?相当于国内什么等级的视力?谢谢!