Flat Top
Bifocal Lenses (FT)
OVERVIEW
A flat top bifocal lens is offers correction for both near and far distances. It is a multifocal lens commonly prescribed for those suffering from both presbyopia and hypermetropia, a condition whereby, with age, the eye exhibits a progressively diminished ability to focus on near and far objects.
The flat top lens includes a segment at the lower half of the lens with a prescription for reading (near distance). The most common width of the flat top is 28mm wide at reading area and looks like the Letter D turned 90 degrees.

(also called a D-seg or straight-top)