bifocal

He had beautiful skin, with rosy cheeks, blue eyes, rimless round bifocal spectacles, resting on the tip of his nose..他皮肤很好，面颊红润，眼睛深蓝，鼻梁上架着一副无框双焦眼镜。

The entire arrangement makes it easy for this bifocal fish to spot a tasty bug flying above the water, or a bit of algae below..这个构造使四眼鱼能够很轻松地发现一只从水面飞过的美味的虫子，或者水面下的一点水藻。

He also made the first pair of bifocal glasses and invented a musical instrument called the glass harmonica and the stepladder chair..他还制作了双光眼镜，以及自己命名为玻璃口琴的乐器和活动梯子。