Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Ophthalmic lenses or blanks
Reexamination Certificate
2001-04-24
2004-03-23
Sugarman, Scott J. (Department: 2873)
Optics: eye examining, vision testing and correcting
Spectacles and eyeglasses
Ophthalmic lenses or blanks
C351S177000
Reexamination Certificate
active
06709106
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a spectacle lens for the correction of an eyesight deficiency of a spectacle wearer as well as to a spectacle lens family comprising a plurality of such spectacle lenses. Furthermore, the invention relates to a method for the manufacture of such a spectacle lens as well as for the manufacture of the spectacle lenses of the spectacle lens family.
BACKGROUND OF THE INVENTION
A spectacle lens for the correction of an eyesight deficiency is characterized by a nominal prismatic power for the correction of an eyesight deficiency as well as by a nominal dioptric power for the correction of the eyesight deficiency, the nominal dioptric power comprising in particular a nominal spherical power for the correction of a spherical eyesight deficiency and a nominal astigmatic power for the correction of an astigmatic eyesight deficiency. To this end, the degree of a spherical cut and a cylindrical or/and toroidal cut of the lens as well as the orientation thereof must be defined. Moreover, in many cases such a spectacle lens also provides a multifocal property which compensates a deficient adaptation capacity of the eye when changing from the viewing of a far object to the viewing of a near object. For this purpose, the spectacle lens has a so-called far-vision reference point and a so-called near-vision reference point spaced apart therefrom, the line of sight of the wearer, when viewing the far-away object, passing through the spectacle lens in the area of the far-vision reference point and, when viewing a near object with the line of sight extending downwardly, passing through the spectacle lens in the area of the near-vision reference point. The mean dioptric power of the spectacle lens at the near-vision reference point differs from the mean dioptric power of the spectacle lens at the far-vision reference point by a predetermined value, the so-called “addition”. A spectacle lens which is adapted to a specific wearer is thus characterized at least by the parameters: nominal dioptric power, optionally the orientation thereof and the desired addition.
The spherical and astigmatic powers are usually indicated in diopters which are usually rounded up or down to the nearest fourth of a diopter.
The term “mean spherical power” as used herein is defined as the mean value of the first and second main cut, as it is, for example, described in DIN 58208, part 1-25.
Due to the multiplicity of the characterizing parameters to be at least employed and the individual differences thereof between different spectacle wearers, it is apparent that an automatic manufacture of spectacle lenses requires an extreme flexibility as far as the parameters are concerned which characterize the spectacle lens.
A spectacle lens for the correction of an eyesight deficiency of a spectacle wearer is known from EP 0857993 A2, said lens likewise exhibiting a multifocal property. In said conventional spectacle lens the lens surface facing away from the wearer's eye is of spherical or rotational-symmetric aspherical design. A plurality of spectacle lenses for the correction of different eyesight deficiencies have this shape of the lens surface facing away from the eye in common so that at least this lens surface is easy to manufacture even in individualized mass production. The correction of the eyesight deficiency, i.e., the provision of a spherical or/and toroidal cut, as well as the multifocal property, are provided by the lens surface facing towards the wearer's eye.
The known spectacle lens has been found to be disadvantageous in so far as the common manufacture of spectacle lenses of specific different combinations of eyesight deficiencies result in excessively thick spectacle lenses and the imaging quality of the spectacle lenses is in need of improvement.
SUMMARY OF THE INVENTION
In one aspect, the present invention relates to a spectacle lens which combines good imaging properties with the ability to mass produce spectacle lenses for the correction of different eyesight deficiencies. In another aspect the present invention relates to a spectacle lens family, the members of which compensate different eyesight deficiencies and, at the same time, can be produced in common in mass production while a comparatively good imaging quality is maintained.
In another aspect, the present invention relates to a method for the manufacture of such a spectacle lens and such a spectacle lens family.
According to a first aspect, the invention provides a spectacle lens for the correction of an eye deficiency of a spectacle wearer, which spectacle lens comprises a lens surface facing towards the eye of the spectacle wearer and a lens surface facing away from the eye of the spectacle wearer.
Preferably, the lens surface facing towards the eye functions directly to correct the eyesight deficiency and its shape is therefore merely defined by a sphere and/or a torus so that, as a result, a nominal dioptric power is produced to compensate the spectacle wearer's eyesight deficiency.
Preferably, the function of the lens surface facing away from the eye comprises, on the one hand, the provision of a multifocal property and, on the other hand, the compensation of certain imaging alterations which are due to the interactions between the eyesight deficiency correction provided by the lens surface facing towards the eye and the multifocal property provided by the lens surface facing away from the eye and which furthermore result from the interaction between the multifocal property and the specific geometric position of the spectacle lens relative to the spectacle wearer. The alterations caused by the geometric position of the spectacle lens relative to the spectacle wearer include in particular the following parameters:
Distance between the two eyes of the spectacle wearer.
The multifocal property of the spectacle lens is perceived by the spectacle wearer as desired if, when viewing a far object, his sightline passes through the far-vision reference point and, accordingly, when viewing a near object, his sightline passes through the near-vision reference point of the spectacle. It has been found that this requirement is fulfilled better if the near-vision reference point is offset further inwards relative to the far-vision reference point for a spectacle wearer having a large eye distance than for a spectacle wearer having a small eye distance.
Distance between the eye of the spectacle wearer and the spectacle lens when worn by the spectacle wearer, i.e., in its position of use.
It has been found that the distance between the eye and the spectacle lens likewise influences the effect of the multifocal property on the spectacle wearer and, accordingly, a correcting design of the lens surface facing away from the eye can be provided to the effect that the spectacle wearer perceives the multifocal property as optimal as possible. In this respect, it is particularly favorable for this distance to be incorporated also in the correction of the interaction between the eyesight deficiency correction and the multifocal property, and, moreover, it is also favorable, in order to define the position of the far-vision reference point and the near-vision reference point relative to one another, to take both the eye distance and the distance between eye an spectacle lens into consideration.
Inclination of the spectacle lens relative to the spectacle wearer when his sightline passes, for example, through the far-vision reference point to a distant object.
The alteration of the interaction between the eyesight deficiency correction and the multifocal property caused by an alteration of the spectacle lens inclination can also be reduced with a known spectacle lens inclination.
Preferred distance between the eye of the spectacle wearer and an object to be viewed in the near zone.
In order for the wearer to perceive viewing as pleasant when changing from distant vision to near vision, the imaging properties of the spectacle lens can also be favorably influenced in that the preferred distance of the
Kelch Gerhard
Wietschorke Helmut
Carl-Zeiss-Stiftung
Rosenthal & Osha L.L.P.
Sugarman Scott J.
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