WO2009103359A1

WO2009103359A1 - Method for the preparation of spectacles for presbyopic emmetropic persons, kit for the implementation of the method, and spectacles thus obtained

Info

Publication number: WO2009103359A1
Application number: PCT/EP2008/061435
Authority: WO
Inventors: Rudolf Hans Pfarrer
Original assignee: Dale View Llc
Priority date: 2008-02-18
Filing date: 2008-08-29
Publication date: 2009-08-27
Also published as: ITPD20080046A1

Abstract

A method for the preparation of spectacles (1) for a presbyopic emmetropic person, comprising the steps of: -providing a frame (2), -providing a plurality of multifocal lenses (3, 3a-3c), all suitable for mounting on the frame, and on each of which a correction area (4) is defined, extending on a lower portion of the lens, starting from a lower edge (5) of same, up to a predefined height (H, H₁, H₂), each of the lenses further having a positive dioptric power suitable for the correction of presbyopia within the correction area and a substantially zero dioptric power outside the latter, the lenses differing from one another in the value of the positive dioptric power and/or in the measurement of the height (H) of extension of the correction area, -selecting from the plurality of multifocal lenses a pair of lenses having a positive dioptric power suitable for correcting the degree of presbyopia of the person and having a suitable measurement of the height of the correction area so that, when the person puts on said spectacles, said correction area is located in a zone of vision preferred for close vision and is not substantially involved in distant vision, and -coupling the selected pair of lenses to the frame in order to obtain the spectacles. A kit is also described for the preparation of spectacles according to the preceding method, and also the spectacles thus obtained.

Description

METHOD FOR THE PREPARATION OF SPECTACLES FOR PRESBYOPIC EMMETROPIC PERSONS, KIT FOR THE IMPLEMENTATION OF THE METHOD, AND SPECTACLES THUS OBTAINED Description Tprhniral fiplr]

The present invention relates to a method for the preparation of spectacles for presbyopic emmetropic persons having the characteristics mentioned in the preamble of the main claim. It further relates to a kit for the implementation of the method, and also to spectacles thus obtained. Tprhnnlngiral harkgrni inH

It is known that with advancing age, people encounter a certain amount of difficulty in the focusing of close objects. This phenomenon, known as presbyopia, can be attributed to a reduction in the capacity for accommodation of the crystalline lens which is no longer capable of varying its curvature in a suitable manner. This defect is independent of defects of vision connected to incorrect focal distance between the crystalline lens and the retina, such as for example myopia and hypermetropia, so that even a person free of such defects, termed emmetropic, is subject to presbyopia.

These people, presbyopic and emmetropic, therefore need to have spectacles provided with a specific optical correction, to be used whenever close vision is required, while they do not need any correction for distant vision.

In order to solve this problem, it is known in this field to use spectacles with a frame of reduced height, known as "half-moon spectacles" or "reading glasses", on which is mounted a pair of lenses provided with positive dioptric power, suitable for correcting presbyopia. These spectacles are normally worn resting on the end of the nose in such a way that, for distant vision, in which a person normally looks straight ahead, in the position known as "primary gaze position", the spectacles are substantially outside the angle of vision. For close vision, on the other hand, the person can take advantage of the corrective power of the spectacles by slightly lowering the gaze, into the reading position, or by wearing the spectacles directly in front of the eyes.

Spectacles of this type are sold, among other things, also in a pre-assembled version, with the lenses already coupled to the frame. In this way they can be made available to the users also at non-specialised points of sale, for example in large stores, and are normally supplied in a plurality of examples differing from one another only in the corrective power of the lenses.

Consequently, the spectacles can be mass-produced on an industrial scale, thus benefitting from the economy of scale in order to keep down the production costs. In spite of their low cost, their wide availability on the market and their substantial efficacy, these spectacles have increasing difficulty in finding favour with the market. The underlying reasons for this lack of appreciation appear to be both of a functional type, arising from the necessity of sometimes having to move the spectacles into different positions on the nose, and of the aesthetic type, arising from the fact that they impart to the person wearing them an undesirable appearance of an "elderly person".

In the technical field of reference, it is also known to use spectacles provided with multifocal lenses.

Spectacles of this type provide a frame on which are mounted lenses of variable dioptric power in which a correction area with positive dioptric power is defined, having a value suitable for correcting the presbyopia of the subject, while the remaining portion of the lens has a zero dioptric power.

These spectacles can be worn in a normal manner, resting on the nose in proximity to the eyes, and their outward appearance does not differ from that of normal spectacles, and they are therefore well accepted by the market.

The main drawback of this type of spectacles, however, lies in their high price. This drawback is a direct consequence of the fact that these spectacles are, in fact, made to measure for each person requiring an accurate evaluation, by specialised personnel, both of the degree of optical correction and of the specific anatomical characteristics of the subject. This latter aspect is particularly important, since the correction area must be located in a suitable position with respect to the eyes of the person wearing them, and this depends substantially on the physical shape of the subject himself.

All these characteristics inevitably increase the cost of spectacles provided with multifocal lenses.

A further drawback of the conventional spectacles with multifocal lenses lies in the fact that the lenses must be suitably produced and then mounted on the frame, inevitably leading to a delay in their delivery to the person who has requested them.

Moreover, in the unfortunate event that the person, on taking delivery of the spectacles, realises that they are not of the correct dimension, the spectacles would not be reusable for another person, with a consequent economic loss to the optician

(or the client).

The problem underlying the present invention is that of providing spectacles for presbyopic emmetropic persons which will remedy the drawbacks mentioned above with reference to the prior art cited.

In particular, it is an aim of the invention to make available to presbyopic emmetropic persons spectacles equipped with multifocal lenses which can be acquired at relatively accessible prices. The aforesaid problem is solved by means of a method for the preparation of spectacles, a kit for the implementation of the method, and also spectacles obtained thereby, produced according to the following claims.

Rripf Hpςrripi-inn nf fhp drawings

The characteristics and advantages of the invention will become clearer from the detailed description of a preferred exemplary embodiment thereof, provided by way of non-limiting example with reference to the appended drawings, in which: -Figure 1 is a diagrammatic view of a pair of spectacles for presbyopic emmetropic persons, produced by a method according to the present invention, -Figure 2 is a diagrammatic view of a kit for the preparation of the spectacles of Figure 1,

-Figure 3 is a diagrammatic view of a pair of test spectacles usable in the method according to the invention, -Figure 4 is a diagrammatic view of an assembly of spectacles similar to those shown in Figure 1. Preferred pmhnrlimpnt¹ nf fhp in\/pn1-inn

In the drawings, the reference 1 indicates as a whole a pair of spectacles for presbyopic emmetropic persons, produced by a method according to the present invention.

In the present context, presbyopia is understood in a general acceptance of "accommodative insufficiency", which may also have an origin of the functional type, determined by the type of stresses to which the eye is subjected. In particular, accommodative insufficiency of this type may be a consequence of the stress arising from prolonged close vision, such as, for example, in the case of an activity which requires the continuous use of a video terminal. The spectacles 1 comprise a frame 2 on which lenses 3 are coupled.

The frame 2 is made of metal or of plastics material, according to methods known per se in the field, and is configured in such a way as to be worn in a position close to the eyes of the user, differing in this respect from the frames used for "half- moon spectacles". The lenses 3 are of the multifocal type and comprise a correction area 4, extending in a lower portion of the lens, starting from a lower edge 5 of the lens, up to a predefined height H.

The correction area 4, identified diagrammatically by dashed lines in Figure 1, has a positive dioptric power, suitable for the correction of presbyopia, while the whole of the remaining portion of the lens 3 has a substantially zero dioptric power.

The value of the height H of the correction area 4 is such that the gaze of a person wearing the spectacles 1 and in the primary gaze position, i.e. in an upright position looking straight ahead, passes through the uncorrected portion of the lenses

3. On the other hand, the correction area 4 is passed through by the gaze of the person wearing the spectacles 1 when turned downwards.

In this way, the distant vision is not affected by the positive dioptric power of the correction area 4, while by slightly lowering the gaze it is possible to take advantage of that dioptric power for close vision.

The value of the positive dioptric power within the correction area 4 may be constant or, in a greatly preferred manner, may vary at a transition zone 6, defined within the correction area 4 in proximity to the portion of the lens 3 having a substantially zero dioptric power.

In the transition zone 6, the positive dioptric power varies starting from the predetermined value for the correction of presbyopia within the correction area 4 to a substantially zero value at the boundary of the correction area 4 with the portion of the lens 3 having a zero dioptric power.

The variation of the dioptric power within the transition zone 6 may follow any suitable course, for example a linear course.

The lenses 3 are mounted interchangeably on the frame 2, for example with a snap coupling, and are selected from an assembly of similar lenses, indicated in Figure 2 by 3a, 3b, 3c, all suitable for mounting on the frame 2.

The frame 2 and the lenses 3, 3a, 3b, 3c form a kit, indicated as a whole by 10, for the preparation of a pair of spectacles 1, according to the method of the present invention. The pairs of lenses 3, 3a, 3b, 3c, while having substantially identical dimensions which allow them to be mounted interchangeably on the frame 2, differ from one another in the positive dioptric power value with which the correction area 4 is provided and/or in the value of the height H of extension of the correction area 4. By way of example, in Figure 2 the lenses 3b and 3c have heights Hi and H₂, respectively lower and higher than H.

In the example described herein, the number of pairs of lenses is four; however, it is clear that the number of pairs of lenses may be any whatever, so as to cover the greatest possible spectrum of values of dioptric power and values of height

H. The values of positive dioptric power are selected from a plurality of predefined discrete values, and preferably start from a minimum value of +0.50, increasing in steps from 0.50 diopters up to a maximum value, for example, +3.50.

In the same way, the values for the height of the correction area 4 are selected from a plurality of predefined discrete values, and are preferably three in number, selected in such a way as to cover the majority of the physical shapes of the population.

The number of predefined values of positive dioptric power and of height of the correction area are such as to cover the requirements of as many of the population as possible, without however reaching an excessively high number of combinations which would render the production and management of the corresponding pairs of lenses uneconomic overall.

The spectacles of the present invention are moreover conveniently usable in cases of accommodative insufficiency resulting from prolonged stress in close vision, as described previously. In particular, in these cases it will generally be sufficient to provide a low degree of correction, for example +0.50, and a generally slightly greater height H with respect to the spectacles used for close vision for conventional use, for example reading.

The kit 10 may conveniently comprise a pair of test spectacles 20, illustrated diagrammatically in Figure 3, comprising a frame 21, similar to the frame 2, on which is mounted a pair of lenses 22 provided with reference marks 23 useful for the selection of the correct value of height H, as described in more detail hereinafter.

The reference marks 23 may comprise a series of lines, substantially parallel to one another, extending so as to be substantially horizontal when the spectacles 20 are worn by a person in the primary gaze position. Each reference mark 23 corresponds to a predefined value of height H, Hi and Hi among those available in the kit 10.

Alternatively, the reference marks 23 may be formed, as well as by lines, by a plurality of bands which may conveniently be differently coloured in order to facilitate identification thereof, both by an expert and by the user himself.

The spectacles 1 are produced and made available to a presbyopic emmetropic person in the following ways.

The frame 2, like the lenses 3, 3a, 3b, 3c and all the other pairs of lenses that may be provided, are produced on an industrial scale so as to keep the cost of production at low levels.

The assembly of suitable lenses on the frame 2 is carried out, according to a first method, by a specialised person, typically an optician who, after measuring the degree of correction necessary for the person who requires spectacles 1, must select the height of the correction region 4 that is most suitable so that the person can enjoy correct vision, both distant and close.

It should be noted that the other typical basic parameter for the making to measure of conventional multifocal lenses, i.e. the distance between pupils, remains substantially irrelevant in this case, inasmuch as the dioptric power, outside the correction area 4, is zero. The selection of the most suitable value for height H may advantageously be made by means of the test spectacles 20. It is in fact sufficient to have the presbyopic emmetropic person put on the spectacles and to check with which reference mark 23 the pupils of the subject are aligned when in the primary gaze position. The most suitable value of height H will be that corresponding to the reference mark 23 aligned with the pupils of the subject. Among the various pairs of lenses available and forming the kit 10, the optician will therefore select those having the correct values of height H and of dioptric power, and will couple them to the frame 2.

Provision is of course made for frames of different styles to be provided, each of which will however be correlated with a respective plurality of lenses having different values for height and/or dioptric power.

In an alternative method, provision is made for the spectacles 1 to be assembled in the factory in such a way as to make directly available to a presbyopic emmetropic person an assembly 100 of pairs of spectacles, from which the person can select the pair most suited to his requirements.

The assembly 100 of pairs of spectacles comprises a series of pairs of spectacles 101, similar to the spectacles 1, all provided with an almost identical frame 2, on which are respectively mounted pairs of lenses 103 differing from one another only in the values for height of the correction region 4 and/or in the dioptric power values of the area itself, similarly to the lenses 3, 3a, 3b, 3c of the kit 10.

The assembly 100 of pairs of spectacles may further advantageously also comprise a pair of test spectacles 20 already described previously.

In this case, provision is made for the subject himself to put on the test spectacles 20 and to identify for himself the value for height of the correction area most suited to his physical shape. For example, provision is made for the reference marks 23 to be formed by differently coloured bands and for each colour to correspond to a different value of height H among those predefined and present in the assembly 100 of pairs of spectacles.

The correct height value will be that corresponding to the colour that can be seen by the subject when, wearing the test spectacles 20, he is in the primary gaze position.

The subject, knowing his own level of presbyopia, is therefore capable of selecting for himself, from among the assembly 100, those spectacles which have mounted on them the pair of lenses most suited to his requirements. In this case, the selection of the most suitable spectacles does not require the intervention of a specialised expert, so that the assembly 100 of pairs of spectacles may conveniently be made available to people on a conventional display, also in a large store.

Naturally, in this case also, provision is made for making available several assemblies of pairs of spectacles having frames differing from one another.

The present invention therefore solves the problem mentioned above with reference to the prior art cited, inasmuch as there are made available, to presbyopic emmetropic persons, spectacles provided with multifocal lenses, wearable in proximity to the eyes and therefore more easily accepted by the market, at a relatively low cost, which is comparable to that of preassembled, fixed gradation spectacles such as, for example "half-moon spectacles".

Claims

C L A I M S

1. A method for the preparation of spectacles (1) for a presbyopic emmetropic person, comprising the steps of:

-providing a frame (2), -providing a plurality of multifocal lenses (3, 3a-3c), all suitable for mounting on said frame, and on each of which a correction area (4) is defined, extending on a lower portion of said lens, starting from a lower edge (5) of same up to a predefined height (H, Hi, H₂), each of said lenses having a positive dioptric power suitable for the correction of presbyopia within said correction area and a substantially zero dioptric power outside said correction area, said lenses differing from one another in the value of said positive dioptric power and/or in the measurement of said height (H) of extension of the correction area,

-selecting from said plurality of multifocal lenses a pair of lenses having a positive dioptric power suitable for correcting the degree of presbyopia of said person and having a suitable measurement of said height so that, when said person puts on said spectacles, said correction area is located in a zone of vision preferred for close vision and is not substantially involved in distant vision, and

-coupling said pair of lenses to said frame in order to obtain said spectacles.

2. A method according to claim 1, wherein the values of said positive dioptric power and of said height of the correction area are selected, for each lens, from a plurality of predefined discrete values.

3. A method according to claim 2, wherein three different predefined values (H, Hi, H₂) for the height of said correction area are provided.

4. A method according to any one of the preceding claims, wherein the selection of the pair of lenses having a suitable height of the correction area comprises the steps of:

-providing a pair of test spectacles (20) comprising a frame (21) similar to said frame (2), on which is mounted a pair of test lenses (22) provided with reference marks (23), each of which corresponds to a lens having a correction area of a different height (H, Hi, H₂), -causing said person to put on said test spectacles and observing with which of said reference marks the pupils of said person are substantially aligned when said person is in the primary gaze position, -selecting from the multifocal lenses of said plurality those corresponding to said reference mark.

5. A kit (10) for the preparation of spectacles for a presbyopic emmetropic person, comprising at least one frame (2) and a plurality of multifocal lenses (3, 3a-3c) suitable for being mounted on said at least one frame, there being defined on each of said lenses a correction area (4) extending on a lower portion of said lens, starting from a lower edge (5) of same, up to a predefined height (H, Hi, H₂), and each of said lenses having a positive dioptric power suitable for the correction of presbyopia within said correction area and a substantially zero dioptric power outside said correction area, said lenses differing from one another in the value of said positive dioptric power and/or in the measurement of said height of extension of the correction region.

6. A kit according to claim 5, wherein the values of said positive dioptric power and of said height of the correction area are selected, for each lens, from a plurality of predefined discrete values.

7. A kit according to claim 6, wherein the values of said height of the correction area are selected from 3 predefined discrete values (H, Hi, H₂).

8. A kit according to any one of claims 5 to 7, comprising a pair of test spectacles (20) including a frame (21) similar to said at least one frame (2) and on which is mounted a pair of test lenses (22) provided with reference marks (23), each of which corresponds to a different value for height (H, Hi, H₂) of the correction area of the lenses of said plurality.

9. A kit according to any one of claims 5 to 8, wherein, within said correction area (4), a transition zone (6) is defined, adjacent to a portion of said lens outside said correction area and, in said transition zone, said positive dioptric power varies from said predefined value to a substantially zero value in proximity to said portion outside the correction area.

10. A kit according to claim 9, wherein said dioptric power varies in a substantially linear manner.

11. Spectacles for a presbyopic emmetropic person, comprising a frame (2) on which is mounted a pair of multifocal lenses (3), on each of which is defined a correction area (4) extending on a lower portion of said lens, starting from a lower edge (5) of same, to a predefined height (H), each of said lenses having a positive dioptric power suitable for the correction of presbyopia inside said correction area and a substantially zero dioptric power outside said correction area, characterized in that said lenses are mounted interchangeably on said frame and said lenses are selected from an assembly of similar lenses (3, 3a-3c), suitable for being mounted on said frame, and having a positive dioptric power value different from said pair of lenses and/or having a correction area extending to a different height (Hi, H₂) with respect to said pair of lenses.

12. Spectacles according to claim 11, wherein, within said correction area (4), a transition zone (6) is defined, adjacent to a portion of said lens outside said correction area and, in said transition zone, said positive dioptric power varies from said predefined value to a substantially zero value in proximity to said portion outside the correction area.

13. Spectacles according to claim 12, wherein said dioptric power varies in a substantially linear manner.

14. An assembly (100) of pairs of spectacles comprising a plurality of pairs of spectacles (101) having substantially identical frames (2), there being mounted on each said frames respective pairs of multifocal lenses (103), on each of which a correction area (4) is defined, extending on a lower portion of said lens, starting from a lower edge (5) of same, to a predefined height, each of said lenses having a positive dioptric power suitable for the correction of presbyopia within said correction area and a substantially zero dioptric power outside said correction area, said pair of lenses having different values for said positive dioptric power and/or having a correction area extending to a different height.

15. An assembly according to claim 14, wherein said values for positive dioptric power and for said height of the correction area are selected from a plurality of predefined discrete values.

16. An assembly according to claim 14 or 15, wherein a pair of test spectacles (20) is provided, including a frame (21) similar to said frames and on which is mounted a pair of test lenses (22) provided with reference marks (23), each of which corresponds to a different value of height of the correction area of the lenses, so as to be able to select, from said assembly, the spectacles provided with lenses having a correction area extending to a height of a suitable value.