Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Ophthalmic lenses or blanks
Reexamination Certificate
2002-07-16
2004-02-03
Sugarman, Scott J. (Department: 2873)
Optics: eye examining, vision testing and correcting
Spectacles and eyeglasses
Ophthalmic lenses or blanks
C351S177000
Reexamination Certificate
active
06685316
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of manufacturing progressive ophthalmic lenses whereof each is produced in correspondence with the individual data of a specific spectacle wearer, in accordance with the introductory clause of Patent claim 1.
Methods which the introductory clause of Patent claim 1 starts out from are known, for example, from the U.S. Pat. No. 2,878,721, the German Patent DE-A-43 37 369, the German trade journal DOZ 8/96, pp. 44 to 46, the trade journal NOJ 11/97, from page 18 onwards, or from the German Patent DE-A-1 97 01 312. In all other respects explicit reference is made to these prior art documents for an explanation of all particulars not described here in more details.
In practical operation, the procedure in the production of ophthalmic lenses is presently as follows—irrespectively of whether mono-focal, multi-focal or progressive ophthalmic lenses are involved:
Initially, an ophthalmic lens finished on one side, mostly “a round blank”, i.e. without pre-edging (in a manner specific of the mount). For reasons of manufacturing techniques, the finished surface of the ophthalmic lens complete on one side is, as a rule, the face surface; the reason for this resides in the fact that the so-called “prescription lens productions” are almost exclusively equipped for machining the concave surface, i.e. the surface on the side of the eye. In the prescription lens productions, the surface on the eye side is manufactured only upon presentation of a concrete order in correspondence with the so-called prescription data of the respective spectacle wearer. In the field of progressive ophthalmic lenses, the prescription data is to be understood to denote the effect required in the so-called reference point in the distant vision range, the addition as well as possibly the amount and the axial position of an astigmatic effect.
In the progressive ophthalmic lenses common in the market at present, the face area is almost exclusively the progressive surface. The reason for this resides in the aspect that the methods of computation and manufacture usual in the past rendered an individualized computation and above all an individualized production of the progressive surface difficult at “enforceable or achievable” sales prices.
For this reason, a great number of so-called base graphs have been computed to “cover” the usually required range of effects. This is to be understood in the sense that a certain number of different progressive surfaces has been computed which are distinguished with respect to the so-called surface refracting power in the reference point in the distant vision range and with respect to the addition—which is mostly defined as the difference of the surface refracting power between the reference point in the distant vision range and the near reference point. These progressive surfaces are combined with different concave surfaces on the side of the eye so that the ophthalmic lens will create the prescribed effect in the reference point in the distant vision range and in the reference point in the near vision range. In other words, a base graph always “covers” a defined range of effects of several diopters.
In the computation of the individual progressive surfaces serving as base graphs or base surfaces, respectively, frequently occurring values of the individual influential parameters have been presumed, such as the pupil separation (PD or ps), the cornea/Apex distance (HAS), the convergence of the eyes when the view is lowered along the so-called main line of sight, possibly as a function of the addition, the forward inclination, the prism, etc. This does not mean anything else but that in the past “individualized” ophthalmic lenses were calculated for a “fictitious average spectacle wearer” whilst it was presumed that these ophthalmic lenses satisfy the majority of demands also when influential parameters at variance there from occur.
In the course of the past few years, however, substantial progress has been achieved both in the rate of optimization of a progressive area and in manufacturing technology so that it has now become possible, even at reasonable manufacturing costs, to compute and manufacture individualized ophthalmic lenses.
The U.S. Pat. No. 2,878,721 proposes to compute a progressive surface that presents also the astigmatic effect in correspondence with the respective prescription. As a logical consequence, the progressive area is the surface on the side of the eyes in accordance with that prior art document.
The German Patent DE-A-43 37 36 equally proposes an individualized progressive surface. In particular, this progressive surface may have an astigmatic effect that is matched with the respective prescription data in terms of the amount and the axial position. The progressive area may be the face surface or the surface on the side of the eyes.
In the articles quoted by way of introduction, which were published in the trade journals DOZ 8/96, pp. 44 to 46 or NOJ 11/97, from page 18 onwards, the alternative technique is proposed to achieve individualization by the provision that starting out from a standardized progressive surface, i.e. starting out from progressive surfaces in the “conventional base graph grading”, the individualization is achieved by combining the progressive surfaces with individually computed non-spherical surfaces as areas on the side of the eyes.
The German Patent DE-A-197 01 312 reflects, in the last analysis, the same disclosure as the German Patent DE-A-43 37 36 or the U.S. Pat. No. 2,878,721:
In order to be able to manufacture the progressive surface in a conventional manner in the prescription lens production facilities, the area on the side of the eyes is configured as progressive surface. A spherical or non-spherical surface is used as face area, whose refracting power in the area apex is graded in a comparatively “coarse” manner in correspondence with the usually employed base graphs.
All the progressive ophthalmic lenses known from the afore-quoted prior art documents share the common aspect that a very specific pairing of face surface and surface on the eye-side is used again and again for a certain “prescription value”. In other words, a special distant-vision effect is always realized by a respective surface power value of the face surface and of the surface on the side of the eyes.
BRIEF DESCRIPTION OF THE INVENTION
In accordance with the present invention it has now been found that particularly when an individualized progressive surface is combined with a spherical or non-spherical face surface, which are then graded in a comparatively coarse manner in correspondence with the common “base graphs”, it is not possible to satisfy the various demands resulting from the individual physiologic conditions of the individual spectacle wearers or the respective conditions of use, respectively.
On the other hand, the use of two progressive surfaces suitable to overcome a number of the disadvantages of the progressive ophthalmic lenses known from the above-quoted articles or prior art documents, still involves a high (expensive) expenditure even with the present state of the art in computer and manufacturing technology.
The present invention is based on the problem of providing a method of manufacturing progressive ophthalmic lenses whereof each is manufactured in correspondence with the individual data of a particular spectacle wearer, which are easy to match to the respective physiologic requirements of the respective spectacle wearer even when only one individualized progressive surface is used.
An inventive solution to this problem is defined in Patent claim 1. Improvements of the invention are the subject matters of claims 2 et seq.
The invention starts out from progressive ophthalmic lenses whereof each
presents a first surface having a defined surface power value (D
1
) in the surface apex, and
presents a non-spherical second surface (prescription surface) whose surface power (D
2
) varies along a line (referred to as principal line in the following) that follows at least appr
Altheimer Helmut
Baumbach Peter
Brosig Jochen
Esser Gregor
Haimerl Walter
Optische Werke G. Rodenstock
St. Onge Stewart Johnston & Reens LLC
Sugarman Scott J.
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