How are flat-top bifocal lenses different from round-topped lenses?

Flat-top bifocal lenses are characterized by their straight top edge, which allows for a larger area for the distance prescription that is typically positioned above the line. This design contrasts with round-top bifocal lenses, which have a semicircular shape at the top, providing a different aesthetic and function.

The straight top edge of flat-top bifocals creates a more pronounced line between the distance and near vision prescriptions, making it easier for wearers to transition between viewing distances. This format is particularly beneficial for individuals who require assistance with both distance vision and reading, as it maximizes the area available for clear distance vision while offering a specific section for reading enhancement below the line.

In contrast to flat-tops, round-tops do not inherently dictate how they are used based on their shape alone—both types can be suitable for various activities, and their selection often depends on the wearer's lifestyle and visual needs. Therefore, flat-top bifocal lenses specifically stand out due to their straight top edge, which distinguishes them from round-tops.