She had plastic bifocals hanging on a chain over her heavy chest .

她沉重的胸前面挂着一架塑料的双光眼镜。

Nowadays , this type of glasses is known as bifocals .

现如今，这种眼镜被称为双光眼镜。

Nowadays , these glasses are known as bifocals .

如今，这些眼镜被称作双光眼镜。

Once the trufocal lenses are adjusted , the entire field of vision is in focus , unlike bifocals and progressive lenses , which keep only a limited area in sharp focus .

一旦调节好trufocal镜片，整个视野就对准焦点了，这与只在有限区域进行锐聚焦的双光眼镜和渐进镜片有所不同。

It is a condition that causes vision to progressively blur with age , causing eye fatigue , poor night vision and reliance on bifocals & reading glasses .

这是一个条件，导致视力随着年龄的增长，逐步模糊，造成眼睛疲劳，夜间视力差，对双光眼镜和老花镜的依赖。