Soft Bifocals and Multifocals

Most people have heard of contact lenses but unfortunately are not aware of all the different options available for them.  What are the different options and benefits? Here are a few that Lenhardt Optometric Group would like to elaborate on: alternating vision, simultaneous vision, concentric ring, and aspheric lenses.  These lenses come in different kinds of materials as well, such as rigid gas permeable, soft, and combination (hybrid) lenses.[1]

Alternating Vision Contact Lenses

Lenses with alternating vision are designed with two different powers.  By alternating your gaze from up to down you are able to see through the two different powers.[2]

Benefits:  Excellent for driving and reading.  A simple shift of your gaze will provide optimal vision needed to see many street signs and small shifts for reading.

Simultaneous Vision Contact Lenses

Lenses with simultaneous vision are designed with both distance and near powers placed in one area.  Your eyes actually learn to adapt and choose the appropriate power.  They are able to do this by determining the distance you are focusing on- whether it is a short or far distance.

Benefits: Will get sharp and consistent vision.  When your eyes adapt to these lenses they [3] will be able to provide constant clear vision.

Concentric Ring Contact Lenses

This type of lens has alternating rings of distance and near prescriptions.  There is a center power and one or more rings surrounding it.  The rings alternate between distance and near powers.

Benefits: Improved depth of focus.[4] When you have good depth of focus you are able to focus the object of interest over large distance of the image plane. [5]

Aspheric Contact Lenses

Lenses that are aspheric are of different powers across the lenses.  The visual system adapts to the power needed to focus for the appropriate distance.

Benefits:  Corrects vision in specific problem areas to achieve the most natural vision possible.  For example, if you have astigmatism, you have problem areas in certain a certain axis.  Aspheric lenses will correct the problem areas to provide crystal clear vision.


[1] Author unknown.  “Multi-focal Contact Lenses.”  Eye Doctor Guide. 2010.
Obtained from web10/14/2010.
www.eyedoctorguide.com/contact_lens/multifocal_contact_lenses.html

[2] Nancy Del Pizzo and Liz Segre; reviewed by Joseph T. Barr, OD. “ Bifocal and Multifocal Contact Lenses.” All About Vision. August 2010.
Obtained 10/08/2010.

[3] www.allaboutvision.com/contacts/bifocals.htm.

[4] Dr. Bender.  “Concentric ring Single Vision lens Designs.” Free Patents Online. November 11, 1997.
Obtained 10/14/2010.
www.freepatentsonline.com/5684560.html.

[5] Lamore, Ray, Mclean, et al… “Depth of Focus.” Wikipedia. September 20, 2010.
Obtained 10/26/2010.
en.wikipedia.org/wiki/Depth_of_focus.