| 摘要 |
<p>A progressive-power lens has one surface which satisifies the following expressions CY DP = CT DP
where CT(DP) denotes a vertical direction curvature at the distance reference point, CY(DP) denotes a horizontal direction curvature, CY(P) denotes a horizontal direction curvature at a point on the principal meridian which is located further on the near portion than the progressive start point, and CT(P) denotes a vertical direction curvature at the point.</p> |
