After age 40 everyone, no exceptions, will begin to notice a paradoxical phenomenon.  The closer you bring something to your eyes, the worse you can see it.  This is called presbyopia and occurs in everyone as a part of the normal process where the crystalline lens inside the eye looses its elasticity. This loss of multifocality means that we now need bifocals or progressive glasses.  Short of exchanging the lens, nothing has been shown to definitively improve or reverse this loss of accommodation.  One of the strategies for dealing with this fact of life is monovision.  Monovision or Blended vision use the concept of retinal rivalry to achieve the goal of increasing the depth of focus. 

 

 

Monovision is a strategy for eliminating the need for bifocals or reading glasses.  The goal of the treatment is to achieve spectacle freedom while performing everyday visual tasks. Monovision can be achieved through the use of contact lenses or LASIK.

 

As a result of treatment, one eye, usually the dominant one, is focused at distance.  The fellow non-dominant eye is focused at near.  With both eyes open, the brain automatically picks the image that is best in focus.

 

For example, when looking at objects that are at near, such as a watch, cell phone or a price tag, the "near" eye is doing most of the work.  While performing tasks that require distance vision, such as driving or watching TV, the "distance" eye does most of the work.

 

This strategy is well tolerated by most people but is not for everyone. For this to be successful, careful pre-operative planning must be done which includes: