BIFOCAL CONTACT LENSES

ASPHERIC

Back surface aspheric lenses give some add power for the presbyope as the back surface geometry causes an increase in plus power from the center towards the edge.  This is another type of simultaneous vision lens.

    Advantages:

       -relatively easy to fit
       -not too expensive


   Disadvantages:

      -can only get low adds (maximum of about 1.50 D.)
      -some blur and flare
      -lens must center well or there is induced cylinder.