| 摘要 |
<p>The invention contemplates a multi-focal spectacle lens with a dioptric power varying progressively between different zones of vision, namely, a progressive lens which, with a short progressive zone, substantially satisfies in the progressive zone as well as in the far-vision and near-vision zones all requirements (monocular and binocular) for sharpness and compatibility, while reducing horizontal and vertical directional errors to tolerable values by selecting distortion on both sides of the principal sight line accordingly.</p> |
