Bifocal lenses will help you to enjoy clear vision at two points of focus:
Distance – such as driving a vehicle or watching television
Near – such as reading or other
On your bifocal lens a small portion is reserved for your near-vision correction and the rest of the lens is for distance correction.
All you have to do is drop your eyes down to read, and lift your eyes up for distant objects. With time, you will notice that your eyes naturally seek out the appropriate portion of the lens.