Abstract: A progressive multifocal ophthalmic lens has a main meridian along at least part of which the curvature of the lens varies continuously. On each side of the main meridian the areas of aberration are symmetrical to each other. The main meridian intersects a horizontal plane through the optical center of the lens at a point which, relative to a vertical plane passing through the optical center, is spherically offset towards the nose. This offset is between 0.8 and 1.33 millimeters. The plane containing the main meridian is at an angle between 5.5 degrees and 7.5 degrees to the vertical plane. The main meridian converges towards the nose in the lower part of the lens.

Abstract: A method of preparing a surface of refraction of a progressively variable power ophthalmic lens, in which a first family of surfaces S.sub.1 having predetermined optical characteristics is determined within a given system of rederence. Within the same system of reference a second family of surfaces S.sub.2 having other predetermined characteristics is determined, each surfaces S.sub.1 of the first family is associated with each surfaces S.sub.2 and their curves of intersection C and D are determined. Among the pairs of surfaces S.sub.1 S.sub.2 is selected that one whose curves C and D provide therebetween a corridor respectively at least 15 and 18 mm wide in the intermediate vision zone Z.sub.2 ' and in the near vision zone Z.sub.3 '. The refractive surface S of the ophthalmic lens is selected so as to have the part of the surface S of the selected pair which is between the curves C and D, and the part of the surface S.sub.2 of the selective pair which is outside curves C and D.

Abstract: A method of making a glass die for moulding progressive concave-convex ophthalmic lenses of organic glass, i.e. of synthetic polymeric material, which have their convex surface of aspheric shape, wherein a glass blank for the die is formed with its convex surface of aspheric shape and is then supported on a support member having a concave spherical support surface while being heated to a temperature at which the glass deforms without flowing, so that the convex surface sags to conform with the spherical support surface and the aspheric character is transferred to the concave surface.