| 摘要 |
A spectacle lens comprises a region (distance portion) designed for viewing at greater distances, in particular, to infinity; a region (near portion) designed for viewing at short distances and, in particular, "reading distances"; and a progression zone located between the distance portion and the near portion, in which the power of the spectacle lens increases from a value at the distance reference point located in the distance portion to the value at the near reference point located in the near portion along a line (principal meridian) curving towards the nose. It is one of the characteristics of the invention that for minimizing the change of imaging properties with horizontal movements of the gaze along a curve described by the points of penetration of the principal rays through the front surface, these principal rays passing through a point having the coordinates (x-dx, y, s) at the beginning of the movement and a point having the coordinates (x +dx, y, s) at the end of the movement, at s=-40 mm and dx=10 mm particular conditions apply.
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