Abstract: A multifocal ocular lens having a vision correction area which includes a central and outer vision correction region, an intermediate region located between the central and outer regions, and an intermediate-distance vision correction region located radially outwardly of and adjacent to the outer region, and which has an optical axis with which centers of these regions are aligned, the central and outer vision correction regions having respective different first and second optical power values, wherein the optical power of the intermediate region located between the central and outer regions is represented by a combination of two different quadratic curves connected to each other at a point of inflection which corresponds to a desired third optical power between the first and second values, and wherein the intermediate-distance vision correction region located radially outwardly of the outer region includes radially inner and outer varying-power zones, the optical power in the radially inner varying-power zon

Abstract: A prism ballast type contact lens having a front and a back surface, a center axis of the front surface being offset from that of the back surface which is a geometric center axis of the lens, such that the lens has a thickness which continuously increases in a downward direction of the lens, the lens further having a slab-off area provided in at least a lower portion of the front surface, wherein at least an optical portion of the back surface and the lower portion of the front surface are formed by molding using a mold assembly including a male and a female mold half which are closed to define a mold cavity that gives a lens blank which is formed into the prism ballast type contact lens, the male mold half having a convex molding surface whose profile follows that of the optical portion of the back surface, the female mold half having a concave molding surface whose profile follows that of at least the lower portion of the front surface, the mold cavity being defined by the convex and concave molding surfac

Abstract: A toric multifocal lens including a plurality of vision correction regions having centers on a common optical center axis, the plurality of vision correction regions providing respective different values of a spherical optical power, each of the plurality of vision correction regions having an optical power for correction of astigmatism, wherein the improvement comprises: at least one of a cylindrical optical power and a cylindrical axis orientation which determine the optical power for correction of astigmatism being different in at least two different vision correction regions of the plurality of vision correction regions, so that the at least two different vision correction regions have respective different values of the optical power for correction of astigmatism.

Abstract: A multifocal ocular lens having a vision correction area which consists of a central, an intermediate, and an outer vision correction region having respective different values of an optical power, and which has an optical axis with which centers of the central and outer vision correction regions are aligned, the central and outer vision correction regions having respectively determined first and second mutually different values of the optical power, wherein the optical power of the intermediate region is represented by a combination of a first and a second quadratic curve connected to each other at a point of inflection which corresponds to a radial position of a boundary between the inner and outer sections, and which corresponds to a desired third value of the optical power between the first and second values, or the optical power of the intermediate region is represented by one polynomial equation whose degree is not smaller than 2 and continuously changes from the first value to the second value with an i