In MO Optics® Prism lenses, the vision-shifting prism segments are produced with powers for near vision, and a lens type most appropriate for the user’s requirements is selected for the surrounding part of the lens. This allows us to build prism solutions even for the most demanding viewing conditions.
Single-vision and bifocal prism lens
In a single-vision prism lens, both the prism segment and the surrounding lens parts have the same corrective powers. This kind of lens works perfectly when there is no need for near vision addition or only a small addition would be required. With stronger near vision additions, the corrective power in the surrounding lens part is usually made for a viewing distance that enables clear vision to mid-range objects, such as instruments or computer screen. A prism lens with different powers in the segment part and the surrounding lens part is called bifocal.
Progressive prism lens
As in all MO Optics® Prism lenses, the segment part is made with powers for working distance. In a progressive surrounding lens, the corrective power of the mid part of the lens is made for viewing mid-range objects, and the power diminishes gradually towards the top part that is used for looking further away. Progressive lenses most suitable for room distances include the so-called enhanced reading glasses and occupational progressive lenses. In these kind of surrounding lenses, the narrow field of vision typical to progressive lenses can be widened by leaving out the area for far distance vision in the very top part of the lens. In addition, this also results in a slower gradual change in the corrective power of the lens, which makes it easier to view various objects.
Roomer prism lens
Roomer prism lenses are especially useful when strong near vision addition is required, but you also need to be able to see well at longer distances. The corrective power in the prism segment is made for the working distance, and you can freely choose the viewing distances for the surrounding areas. Compared to progressive lenses, Roomer lenses have the benefit of wider fields of vision.