| 摘要 |
A progressive power lens provides a large clear vision area from a far-distance use section to a progressive section, wherein an astigmatism imbalance during vision through both eyes is eliminated, and eye movement between far and near distance use takes place smoothly. Astigmatism is distributed asymmetrically in the progressive region of the progressive power lens with respect to a meridian in such manner that a larger astigmatism occurs in a nose-side region than in an ear-side region. By so doing, distribution of astigmatism in the nose-side progressive region is eased to match that of the ear-side progressive region. Moreover, by making the increasing ratio beta of the astigmatism in the far-near direction milder than the increasing ratio alpha of the astigmatism in the left-right direction, a large clear vision area is obtained and the astigmatism imbalance during vision with both eyes is eliminated. Moreover, eye movement between the far-distance use and near-distance use takes place smoothly.
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