Essilor International

Francedillaoise Ahsbahs

Bernard Bourdoncle

Claude Pedrono

Christian Miege

Benedicte Deldalle

In a pair of progressive multifocal ophthalmic lenses, in which each lens has an aspherical surface comprising a far vision portion, a near vision portion, an intermediate vision portion, and a prime meridian of power progression passing through these three portions, the prime meridians of progression of the lenses are substantially symmetrical with respect to each other, and one of the lenses is more particularly dedicated to far vision and the other is more particularly dedicated to near vision, the lens dedicated to far vision having a more extensive far vision portion than the far vision portion of the lens dedicated to near vision, and the lens dedicated to far vision having a less extensive near vision portion than the near vision portion of the lens dedicated to near vision.

Progressive multifocal ophthalmic lens pair

A progressive multifocal ophthalmic lens is provided having an aspherical surface with a mean sphere and a cylinder at every point. The aspherical surface has a distance vision portion, with a control point for distance vision, a near vision portion with a control point for near vision, and an intermediate vision portion between the near vision portion and the distance vision portion. A power addition value A is defined as a variation in mean sphere between the control point for distance vision and the control point for near vision portion. A base B is defined as a value of mean sphere at the control point for distance vision. A width of the near vision portion varies not only as a function of the power addition value A, but also as a function of the value B of the base. The invention thereby ensures the presence of a substantially constant object field for all values of the power addition and of the base.

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Paris, France

Francedillaoise Ahsbahs