| 摘要 |
A multifocal lens has a main lens with a far vision surface refracting power sphere (F) and a near vision sphere (N) and a progressive focal area (P) or an intermediate vision sphere (I), a progressive focal point (P) and a near vision sphere (N) on a segment thereof for giving additional refracting power by surface refracting, in which case the segment projects from the main lens, or refractive index, in which case the segment is embedded in the main lens. A separately produced segment can also be stuck to the surface of the main lens, in which case a series of prism segments can be prepared in advance to select an optimum segment from the series of prism segments according to a prescription.
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