Ophthalmic lenses are generally divided into several categories namely single vision, bifocal and progressive.

Single Vision
-  One lens, one power
-  General use
-  For presbyopes, lens only provide specific range of viewing distance

Bifocal
-  One lens, two powers
-  Visible line separates the viewing areas
-  Can see near and distant objects in one lens
-  May not be good for intermediate distance

Multi-focal (progressive lens)
-  One lens, multi-powers
-  No distracted lines (look like single vision lens)

Can see near, intermediate and distant objects in one lens