TruFocals emulate the youthful human eye's ability to adjust focus by utilizing a lightweight two-lens system. Each "lens" is actually a set of two lenses, one firm and one flexible. The firm front lens holds the distance prescription (including astigmatic and prism corrections). The flexible lens (near the eye) has a transparent distensible membrane attached to a clear rigid surface. The pocket between them holds a small quantity of crystal clear fluid. As one moves the slider on the bridge, it pushes the fluid and alters the shape of the flexible lens. Changing the shape changes the correction. This movement mimics the way the natural lenses perform in the youthful human eye. The sliding movement allows one to choose the exact correction that works best at any distance and under any lighting conditions. The front lens can be removed for cleaning, or interchanged with appropriately tinted prescription lenses to be used as sunglasses.
