If you are over 40 and have difficulty seeing close up, you probably have a common age-related condition called presbyopia which is when the eye’s natural lens loses the ability to focus on close objects. Presbyopia is a natural process as the eye ages and affects the majority of people from age 40 and upward. Individuals with presbyopia are often familiar with the need to hold reading materials such as newspapers an arm’s length away from their eyes in order to see clearly, yet reading glasses with bifocal or multifocal (progressive) lenses can help.
Fortunately for those who don’t like the look, feel or inconvenience of reading glasses, there is another option. Bifocal and multifocal lenses are also available in contact lenses in both soft and Rigid Gas Permeable (RGP) varieties.
Multifocal contact lenses give you added freedom over glasses and they allow you to be able to view any direction – up, down and to the sides – with similar vision. People wearing progressive lenses in glasses on the other hand have to look over their glasses if they want to view upwards or into the distance.
Simultaneous vision lenses
The most popular version of multifocal contact lenses, simultaneous vision lenses present the distance and near vision zones of the lens at the same time. Typically after a short adjustment period your eyes learn to utilize the segment of the lens that they need to focus on the desired object and essentially ignore the other.
They come in two designs:
- Concentric ring design: In the most basic form these are bifocal lenses that are comprised of a central circular area of one power with a ring around of the alternate power, similar to a bulls-eye. In this design the power of the rings (either near or distance vision is interchangeable). For intermediate viewing (18-24 inches away) extra rings can be added to create a trifocal or multifocal lens. The width of each ring is variable depending on the power that is needed most and the edges of the rings can be blended for a smooth transition of focus, similar to progressive eyeglass lenses.
- Aspheric design: These multifocal lenses attempt to provide a natural vision experience by blending many lens powers across the surface and center of the lens. In this design both distance and near vision power are located in the central visual area and your eyes will adapt to focus on the area needed to view what you are looking at.
An Alternative Option to Multifocal Contact Lenses: Monovision
Monovision is another contact lens alternative for presbyopia particularly if you are having difficulty adapting to multifocal lenses. Monovision splits your distance and near vision between your eyes, using your dominant eye for distance vision and your non-dominant eye for near vision.
Typically you will use single vision lenses in each eye however sometimes the dominant eye will use a single vision lens while a multifocal lens will be used in the other eye for intermediate and near vision. This is called modified monovision. Your eye doctor will perform a test to determine which type of lens is best suited for each eye and optimal vision.