Multifocal ophthalmic lens

摘要

The lens has a main aspherical surface (S) presenting a mean sphere and a cylinder at any point and having a distant vision zone (VL), a near vision zone (VP) and an intermediate vision zone (VI), with a main meridian of progression (MM') passing through all three zones, and an addition. The main meridian of progression is formed from the centers of horizontal segments connecting the respective lines formed by the points of a cylinder of 0.50 diopter and its length is less than 16 mm. The maximum value of the module of the tangential derivative of the mean sphere on a circle of diameter 40 mm with its center on the geometrical center of the lens is less than a quarter of the maximum value of the mean sphere's inclination along the meridian. The maximum value of the cylinder inside the circle is less than the nominal addition of the lens.