Patent ID: 6142627
Filing Date: 2000-11-07
Classification: G02C

Abstract:
A progressive power ophthalmic lens having:a distance zone;a distance fitting center;a near zone having a reading portion;an intermediate zone having a short progressive corridor; andan astigmatism relationship, .rho., of at least 2.7where.rho.=<.nu.>.sub.3+4 /<.nu.>.sub.1+2,and where <.nu.>.sub.1+2 is the gradient of surface astigmatism of the lens between diopter magnitudes D.sub.1 and D.sub.2 averaged over first and second arcs of a circle of 30 mm diameter superimposed on the lens and centered 2 mm directly below the distance fitting center of the lens,and where <.nu.>.sub.3+4 is the gradient of surface astigmatism of the lens between diopter magnitudes D.sub.1 and D.sub.2 averaged over third and fourth arcs of a circle of 30 mm diameter superimposed on the lens and centered 2 mm directly below the distance fitting center of the lens,said third and fourth arcs being in the lower hemispheres of said circle and being on opposite sides of said reading portion; andsaid first and second arcs being above said third and fourth arcs and being in regions of surface astigmatism of about 0.5 D or greater.