| 摘要 |
<p>A progressive spectacle lens has a convex front surface and a concave inner surface. At least one of these surfaces provides an increase in effect from an area suitable for long-sight, via a progression area up to an area suitable for near-sight, along a plane or sinuous main meridian along which the total astigmatism is « 0.5 dpt. To form additional seeing channels, the effect-increasing surface(s) has at least one additional line that does not intersect the main meridian extending from the long-sight area to the lower edge of the spectacle lens and along which the surface astigmatism has a local minimum value. Better viewing possibilities are thus provided, especially when several vertical areas have to be successively observed without moving the head.</p> |
