Abstract: In a multifocal ophthalmic lens comprising an aspherical surface having at every point thereon a mean sphere and a cylinder, a far vision region, a near vision region, and an intermediate vision region, the length of progression i.e. the length over which lens power varies by a set amount in different regions of the lens, is short. To avoid distortion at the periphery of the lens which this would otherwise occasion, the isosphere and isocylinder lines are distributed over the surface of the lens so as to ensure variations in sphere are not too sudden along a 20 mm radius circle centered on the geometric center of the lens and variations in cylinder on the surface of the lens inside this circle are also very small. The lens has an enlarged near vision region and progression is less perceptible to the wearer.

Abstract: In a pair of progressive multifocal ophthalmic lenses, in which each lens has an aspherical surface comprising a far vision portion, a near vision portion, an intermediate vision portion, and a prime meridian of power progression passing through these three portions, the prime meridians of progression of the lenses are substantially symmetrical with respect to each other, and one of the lenses is more particularly dedicated to far vision and the other is more particularly dedicated to near vision, the lens dedicated to far vision having a more extensive far vision portion than the far vision portion of the lens dedicated to near vision, and the lens dedicated to far vision having a less extensive near vision portion than the near vision portion of the lens dedicated to near vision.

Abstract: A progressive multifocal ophthalmic lens is provided having an aspherical surface comprising a distance vision portion, a near vision portion and an intermediate vision portion, in which the maximum mean sphere gradient value is situated in the intermediate vision portion of the principal meridian of progression of the lens, and the cylinder gradient over the whole aspherical surface of the lens is less than the product obtained by multiplying the power addition value at each point by a constant value coefficient.

Abstract: The proximity P of a simultaneous vision optical lens for correcting presbyopia is defined as the reciprocal of the distance D at which a light ray parallel to and at a distance h from its axis crosses the axis after passing through the lens. The curve representing the proximity P of the lens lies between a lower envelope curve P.sub.inf and an upper envelope curve P.sub.sup satisfying the following equations:P.sub.inf =f(h)=(.SIGMA.A'.sub.i h.sup.i)+P.sub.VLP.sub.sup =f(h)=(.SIGMA.A".sub.i h.sup.i)+P.sub.VLin which P.sub.VL is the proximity for distant vision and A'.sub.i, A".sub.i are numeric coefficients depending on the proximity addition added for near vision to the proximity for far vision. The lens may be implemented as a contact lens, an intra-ocular implant or an intra-corneal lens.