E-commerce is a major factor in the U.S. economy because it assists companies with many levels of current business transactions, as well as creating new online business opportunities that are global in nature.
Eye Health. A bifocal is a lens that has two focal points, usually one lens for viewing distant objects, and one lens for viewing close objects. A bifocal is also known as a multi-focal lens. Ben Franklin is credited as the inventor of the original bifocal lens. Presbyopia.
If you want to use a pair of bifocals to reconfigure your prescription to get computer vision in the top part of your lens and reading vision in the bottom, do the same thing you would do for single vision computer glasses.