Single Vision Lens

Single vision lenses have the same optical focal point or correction over the entire area of the lens. 
Most wearers will need single vision lenses to answer their visual needs, whether it is to see up close or see things far away.
As a solution for presbyopia, single vision lenses only correct near vision. To see things far away, you need to remove your glasses or look over them.

Progressive Lens

Progressive lenses provide a smooth transition from distance to near vision, allowing the viewing of all intermediate distances.
Progressive lenses are the optimum solution for presbyopia.
These are designed to restore clear and accurate vision at all distances, without needing to constantly change glasses. The upper part of the lens makes it possible to see things far away, the central part to see the middle distance and the lower part to see close up.

Bifocal Lens

Bifocal lenses usually have a build in “D” shaped segment that defines separation of the top area which is for distance vision and the bottom area in the segment reserved for reading. Because of the abrupt change, some people report headaches, dizziness and eye fatigue when trying to focus on a new object with standard bifocal lenses.