Patent ID: 7066597

Claim:
A progressive ophthalmic lens element including a lens surface having an upper viewing zone having a surface power to achieve a refracting power corresponding to distance vision, a lower viewing zone having a different surface power than the upper viewing zone to achieve a refracting power corresponding to near vision, and an intermediate zone extending across the lens element having a surface power varying from that of the upper viewing zone to that of the lower viewing zone; one or more of the upper, intermediate and lower viewing zones being designed optically to reduce or minimise a selected measure of blur for the corresponding range of object distances, and wherein the selected measure of blur is the RMS power error, the surface integral of the weighted RMS power error being minimised over an area limited by a prescribed variable distance from the visual fixation locus in one or more of the upper, intermediate and lower viewing zones; at least a portion of the peripheral region of the surface of the ophthalmic lens element being designed to reduce or minimise one or more surface characteristics known to correlate with the sensation of swim.