| 摘要 |
An ophthalmic lens with an aspherical face is provided having a near vision region which is larger in size and wider than that of conventional multifocal lenses, and having reduced aberrations and, notably, astigmatism. Using DELTA to signify a difference in mean sphere between the near vision control point and the geometrical center of the lens, this is achieved by making a surface area defined by points less than 20 mm from the geometrical center of the lens, and for which cylinder is comprised between 0.42 DELTA and 0.84 DELTA greater than the surface area defined by points less than 20 mm from the geometrical center, and for which cylinder is less than 0.42 DELTA .
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