Each"lens" is actually a set of two lenses, one flexible and one firm. Theflexible lens (near the eye) has a transparent distensible membraneattached to a clear rigid surface. The pocket between them holds asmall quantity of crystal clear fluid. As you move the slider on thebridge, it pushes the fluid and alters the shape of the flexible lens.Changing the shape changes the correction. This mimics the way thelenses in your eyes used to perform when you were younger.
This allows you to choose the exact correction that works best foryou at any distance and under any lighting conditions. The result:clear, undistorted vision over a wide field of view: no zones, no lines.
Source: trufocals.comAdded: 12 January 2010