Single vision type lenses are one of the most common in vision correction. It means the lenses are correcting for one field of vision—nearsightedness, farsightedness and astigmatisms. The entire lens contains the same amount of vision correction.
Progressive lenses provide uninterrupted vision from distance to near without any visible lines between the zones. Progressive lenses’ seamless transition from distance correction on top to reading correction on bottom provide much sharper overall vision.
Bifocal lenses have two (2) distinct powers which are divided by a distinct line to separate.