Bifocals are for you if you need two separate prescriptions, one to see clearly at a distance and another prescription to see close. You are  both nearsighted and farsighted.  A small portion in the lower part of the bifocal lens contains the power required to correct your near vision. The rest of the lens usually is for your distance vision.  You may find an “image jump” that occurs at this visible line between the distance and the reading areas obtrusive, especially if you have mobility issues and must look down when walking. 

Bifocals provide a cost effective and convenient way to combine two working distances in one lens. Although not as cosmetically appealing as a varifocal lens, bifocal lenses are functional and simple to use.

The lens segment devoted to near-vision correction can be one of several shapes:

• Half-moon — also called a flat-top, straight-top or D segment
• Found segment
• Narrow rectangular area, known as a ribbon segment
• Full bottom half of a bifocal lens, called the Franklin, Executive or E style

Most presbyopes these days choose line-free progressives.