Multifocal progressive ophthalmic lens with a relatively rapid change of the refractive power

摘要

The invention concerns a progressive multifocal ophthalmic lens, comprising an aspherical surface, with an addition value equal to the difference of the mean sphere between a reference point of the near-vision region and a reference point of the far-vision region. It has a progression length less than 12 mm, the progression length being equal to the vertical distance between a mounting cross and the point of the meridian where the means sphere value is higher by 85 % of the addition value than the sphere value at the reference point for far-vision. To provide the lens with good vision characteristics, not only about the meridian, but also in the extrafoveal vision regions, the ratio between the integral of the product of the cylinder by the gradient norm of the sphere, on a circle with a diameter of 40 mm centred on the lens and the product of the area of said circle, the addition value and the maximum value of the gradient norm of the sphere on part of the meridian included in that circle is less than 0.14.