Bifocal glasses lenses are designed to provide clear vision at two distinct distances—usually distance vision at the top of the lens and near vision at the bottom. This dual-prescription setup is separated by a visible line, making it easy for the wearer to switch between looking far and near by simply adjusting their gaze. Bifocals are particularly useful for people who require distinct corrections for activities like driving and reading, offering a straightforward solution for those with presbyopia or other vision issues.

Although varifocals, or progressive lenses, have become more popular due to their seamless design and lack of a tell-tale line across the lens, bifocals still have their benefits. The clear distinction between the two vision zones in bifocals can make it easier for wearers to quickly adjust their focus, which some find more comfortable and intuitive. Additionally, bifocals can be a more affordable option and are often recommended for those who may have difficulty adapting to the gradual transitions in varifocal lenses.