System incorporating two different sphero-non-spherical contact lenses for correcting presbyopia

Abstract From the Canadian patent

The first contact lens (1) is placed on the dominating eye and includes a central spherical area (5) for distance vision which is, surrounded by an annular non-spherical area (7) having a diopter in the form of progessive addition which varies from zero addition at the inner periphery to a maximum addition at the outer periphery and which enables vision, at all distances including reading. The second contact lens (3) is placed on the dominated eye. The central area (13) is spherical and adjusted for reading. The non-spherical annular area (15) has a progressive reduction from maximum addition to zero addition which enables vision from reading to intermediate and distance vision. This system …