bifocals
bi·fo·cals / ˈbaɪˌfoklz ; baɪˈfəʊkəlz /noun pl.
1. special glasses with an upper part made for seeing things that are far away, and a lower part made for reading双光眼镜〔镜片上部用以看远处物体，下部用以阅读的眼镜〕
—bifocal adj.