an uncorrected visual acuity of at least 20/40 (6/12) with both eyes open. : D' e* D: o# \: A* C3 M
visual aids (glasses or contact lenses) must have vision of 20:20 (6:6) with both eyes open. 0 m+ L4 u- ~. B, `3 \, B0 I( B
" a+ l( Y3 N) j3 Q, i( L! 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!