Series of lenses

Abstract

The present description refers to a series of progressive lenses, wherein the lenses present a different surface power in the distance-vision part and/or a different increase of the surface power from the distance-vision part towards the near-vision part (termed addition Add hereinafter), and whereof each comprises a front surface having a continuously varying surface power which increases from the respective value BK ›dpt!, which is suitable for distance vision, at the point having the coordinates x=0 mm, y=8 mm in the lower region of the distance-vision part along a wound line (primary line), which coincides approximately with the primary line of view, with eyes dropped, towards a value suitable for near vision in the upper region of the near-vision part, which value is greater than the value of the surface power BK in the lower region of the distance-vision part by the value ADD ›dpt! of the addition, and having a surface, in particular the surface on the concave side, which has a spherical shape or an aspherical shape, respectively. The present invention is characterized by the aspects that for the maximum height y of the line on which the surface astigmatism is 0.5 dpt and which defines the lower limit of the region suitable for clear vision on either side of the primary line at a distance of 25 mm, applies: y=f(Add,BK)=b(BK)+a/Add*1000) b(BK)=a.sub.0 +a.sub.1 *BK+a.sub.2 *BK.sup.2 and that for the coefficients on the nose side and the temporal side of the primary line applies: ______________________________________ nose side temporal side ______________________________________ a -8.5 .+-. 20% -7.5 .+-. 20% a.sub.0 18...19 mm 19...20 a.sub.1 -3580 .+-. 29% mm.sup.2 -4520 .+-. 20% mm.sup.2 a.sub.2 390 000 .+-. 20% mm.sup.3 480 000 .+-. 20% mm.sup.3. ______________________________________

Dependencies are inferred from the claim text.