Distance up top, Near Down low. That is the basics of bifocal eyeglasses. We have all heard the story of how Ben Franklin combined two lenses to create the first pair of bifocals. And today they are widely used in sunglasses, prescription eyeglasses and regular reading glasses.
This is an example of a regular pair of bifocal glasses with clear lenses. This pair has plano on the top half and a reading add on the lower portion of the lens. This style is perfect for meetings as you do not have to keep putting on and taking off your glasses as you switch focus from your notes to the other people in the meeting.
For a more sporty and versatile style, bifocal sunglasses are perfect for boating or just relaxing with a book outside. Just like the indoor variety, these readers allow you to look through the bottom half of the lens for enhanced near vision. While the upper lens is a regular sunglass lens that allows you see with your normal distance vision.