Monovision contact lenses are prescribed to people with presbyopia, which is a condition characterized by farsightedness caused by a loss of elasticity in the eyes. Presbyopia is a vision problem that can be a little tricky to address, especially if there are other existing conditions. Monovision contact lenses often have one lens addressing farsightedness, and the other for nearsightedness.
How does monovision work, exactly? Of our two eyes, there is a dominant eye, which commands the brain’s attention as visual information is transferred. Of course, the non-dominant eye still functions, but the dominant eye is the “driver.” Even if the non-dominant eye is fitted for near vision, it will not interfere with the transmission of visual information between the brain and the dominant eye. Often, the brain will adapt to the two extremes, but the adjustment period is often characterized by nausea and headaches. Monovision contact lenses are more effective than monovision glasses because the contacts sit directly on the surface of the eyes.
Monovision contact lenses are very effective for people with presbyopia—with 75 percent of users reporting that their vision problems are addressed by this method. However, monovision contact lenses are a compromise at best, which means that there are minor issues and problems that would not be addressed directly. One such side effect is diminished depth perception and occasional headaches because of the different lens powers on each eye. There are also reports of reduced vision sharpness for people wearing monovision contact lenses, especially when viewing objects at a distance. This reduced vision sharpness often goes away after two to three weeks once the eyes have adjusted to the different lens powers.
Consulting with an eye doctor if you suspect that you have presbyopia, which is a condition that occurs in middle age.