• Single Vision - Lenses with only a distance or near prescription, but not both.  Popular choice for occupational glasses (computer glasses, reading glasses). 
• Bifocal Lenses - Lenses with a prescription at the top for distance and a line with a prescription for reading on the bottom.
• Trifocal Lenses - Lens segments ground separately to give clear vision close up, far away, and in between.  Useful for occupational tasks because they offer wide near and intermediate zones.  Ideal for plumbers, painters, carpenters, electricians, etc.
• Progressive Lenses - Also known as "no-lines".  The distance portion is at the lens top, just as in a bifocal, but instead of a line telling the wearer where the near portion is, there is a gradual change in focus from arm-length all the way to reading distance.  Progressive lens wearers just move their eyes to the proper part of the lens to look at different distances.