| 摘要 |
A measurement position F for measuring far diopters is set at a position 14 mm above a geometric center O of a lens, a measurement position N for measuring near diopters is set at a position 17.5 mm below the geometric center O of the lens and 2.5 mm toward the nose, and an eyepoint position E as a position through which a gaze of a bearer of the lens passes when the bearer gazes at the front is positioned at a position 1.0 mm toward the nose from the geometric center O of the lens in the horizontal direction. A far distinct vision region is defined by a sector Df that has two radii extending in 30~ and a 150~ directions with respect to a reference line extending to the right in the horizontal direction from the far diopter measuring position F. Astigmatism in this region is set to not greater than 0.50 diopters. The lens is asymmetric with respect to a main gaze line which passes through the three points, i.e. the measurement position F for measuring the far diopters, the eyepoint position E and the measurement position N for measuring the near diopters. This graded multifocal lens secures a broad intermediate portion and a near portion, has small rocking and puts importance on the intermediate diopters.
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