- Lined bifocal lenses are often referred to as FT-28 or FT-35. They have your distance prescription on top and a separate semicircular area for reading on the bottom. This is the lens most people think of when they hear the word “bifocal.” When you enter your prescription into our form, your bifocal power is often marked as “ADD” or “Addition,” and it is almost always the same for both eyes.
- FT-28 and FT-35 are describing the bifocal section itself. “FT” stands for Flat Top, which is describing the semicircle shape of the lens, which is flat on the top. The “28″ and “35″ are describing the width of the semicircle. FT-28′s are 28mm wide, and FT-35′s are 35mm wide.
FT-28 (Bi-Focal Lenses)