| 摘要 |
PURPOSE: To form a wide progression zone and to set up face astigmatism on a slide field face to a value smaller than a maximum value by forming a short progression zone between a far sighted part and a near sighted part, providing wide effective width between the progression zone and a near sighted zone and setting up the maximum value of face astigmatism on the slide field face to a value smaller than 1.1 times of a face addition value. CONSTITUTION: The slide field face is constituted so as to continuously express differences twice and has a far sighted zone 2, a near sighted zone 4 and a progression zone 3 arranged between both the zones 2, 4. The average face refraction value of the zone 2 is set up to +3.0dpt to +7.0dpt. The average refraction value of the zone 3 is increased only by a face addition valueΔD1 between +0.75dpt and +3.0dpt up to the zone 4 and a main visual line 5 along a curve curved to the nose side from the zone 2 to the zone 4 divides the slide field face 3 into a nose side area and a temple side area.
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