| 摘要 |
The present invention relates to a design method of a group of progressive power multifocal lenses having a far vision power measuring position, a near vision power measuring position, and an eye-point position where a visual line passes through when a lens wearer faces the front, wherein when a surface refractive power difference between the far vision power measuring position and at the near vision power measuring position is regarded as an addition Di (unit:diopter). A width (W(Di, X) (mm)) of a zone, wherein a value of the astigmatism along a horizontally sectional curve including the near vision power measuring position is not more than X (diopter), has addition (Di) in a range from at least 0.75 to 3.00 (diopters). Arbitrary two progressive multifocal power lenses whose addition Di are represented by Da and Db respectively, out of the group of progressive power multifocal lenses, satisfy a relation Of W(Da, 1.00) ) > W(Db, Db/Da) under the condition that Da > Db. A principal fixation line is set as one curve line passing through three points of said far vision power measuring position, near vision power measuring position, and eye-point position. A horizontal deviation (H) of an arbitrary point (P) on the principal fixation line toward the nose relative to the far vision power measuring position is given by: H = K.Dp/Di where K designates an arbitrary constant satisfying an inequality relation: 1.0 ‰ K ‰ 4.0 and Dp an additional surface refractive power at the arbitrary point (P). |
