| 摘要 |
<p>A multifocal lens (10) for eyeglasses, provided with portions of different indexes, such as for far vision and near vision. The multifocal lens is given a predetermined degree of addition Add by making the difference between an average refractive index D11 of the far vision portion (11) and an average refractive index D12 of the near vision portion (12) on the outside (2) of the lens numerically smaller than the degree of addition Add, and by adjusting an average refractive index D21 of the far vision portion and an average refractive index D22 of the near vision portion on the inside (3). The average refractive indexes D11 and D12 of the outside (2) can be so adjusted as to reduce the difference in magnification between the portions for far vision and near vision. The difference between the average refractive indexes D11 and D12 of the outside (2) can also be reduced. Thus, it is possible to provide a multifocal lens which has less image fluctuation or distortion, as might otherwise be caused by the magnification difference, and which can provide comfort with improved astigmatism, widen a range of distinct vision and reduce the image fluctuation.</p> |
