WO2002017001A1 - Ophthalmic contact lens with uniform edge - Google Patents
Ophthalmic contact lens with uniform edge Download PDFInfo
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- WO2002017001A1 WO2002017001A1 PCT/FR2001/002658 FR0102658W WO0217001A1 WO 2002017001 A1 WO2002017001 A1 WO 2002017001A1 FR 0102658 W FR0102658 W FR 0102658W WO 0217001 A1 WO0217001 A1 WO 0217001A1
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- WIPO (PCT)
- Prior art keywords
- lens
- edge
- profile
- section plane
- reference axis
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- G—PHYSICS
- G02—OPTICS
- G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
- G02C7/00—Optical parts
- G02C7/02—Lenses; Lens systems ; Methods of designing lenses
- G02C7/04—Contact lenses for the eyes
Definitions
- the present invention relates to an ophthalmic contact lens of the non-axisymmetric posterior face type, that is to say that does not have a symmetry of revolution.
- the front face of a contact lens is the convex face of this lens which is opposite to the eye, while the rear face of a lens is the concave face of this lens which is in contact with the eye.
- the front face of the lens is determined so as to obtain, in combination with the rear face, the desired optical correction.
- the two faces, anterior and posterior, of the lens being defined in this way, it remains to connect these two faces to form the edge of the lens.
- document US Pat. No. 5,880,809 describes a contact lens whose posterior face comes into correspondence with the surface of the cornea and whose edge has a circular profile whose radius varies along the periphery of the lens, while remaining greater than a predetermined minimum radius (see column
- the document US Pat. No. 5,452,031 also describes a contact lens whose edge is defined as a function of the shape of the surface of the cornea, so as to improve the comfort of the wearer by promoting exchanges of lacrimal fluid.
- the fact that the lens edge is optimized as a function of the particular shape of the wearer's cornea is independent of the regular or irregular nature of this edge.
- no particular provision is made with regard to the regularity of the lens edge, so that in the event that the posterior face of the lens is non-axisymmetric to be adapted to the surface of the cornea, it inevitably leads to a lens edge having an irregular profile.
- an ophthalmic contact lens with a non-axisymmetric rear face is proposed, this lens having an edge having, in cross section through any plane passing through a central reference axis of the lens, a profile of constant shape and dimensions over all around the lens.
- the shape of the lens edge is well determined makes it possible, from a physiological point of view, to ensure good comfort for the wearer and, consequently, better tolerance of the eye with regard to the lens. Therefore, the combination of such a regular profile edge with the non-axisymmetric shape of the posterior face, adapted to the wearer's eye, gives the lens optimal properties both in terms of its tolerance by the eye and in terms of effectiveness of the optical correction it operates.
- the general orientation of the profile of the edge of the lens in its section plane varies with respect to the central reference axis as a function of the section plane considered around this axis.
- a lens edge is thus obtained which, like the rear face, is not axisymmetric, but which on the other hand retains a profile of perfectly regular and controlled shape and dimensions.
- This variation in the general orientation of the profile of the edge of the lens makes it possible to optimize the connection of the edge of the lens to the posterior and anterior faces of this lens. It is in fact understood that these two faces are by definition irregular and therefore have, in cross section through a plane passing through the central reference axis of the lens, a tangent of connection at the edge of the lens which forms, with respect to at this reference axis, a variable angle over the entire turn of the lens.
- the general orientation of the profile of the edge of the lens is such that this profile is connected continuously with the trace, in the section plane considered, of one of the posterior and anterior faces of the lens and in the immediate extension of this face, without an intermediate connection zone.
- This avoids the presence, in the connection area of the rear face of the lens at the edge of this lens, of an angular line which could, by friction or simple contact, irritate the cornea and could thus prove to be a source discomfort or even rejection of the lens.
- the posterior surface of the lens remains fully defined as a function of the cornea, with no connection zone at the edge which could prove to be a source of discomfort.
- the edge of the lens is connected to the other of these faces by means of a connection leave establishing, whatever the section plane considered around the central axis of reference, continuity between the trace of this other face and the profile of the edge of the lens in the section plane considered. This protects the eyelid from any irritating contact or friction with an angular connection zone from the anterior surface to the edge of the lens.
- the edge of the lens for a sufficient adaptation of the edge of the lens to the irregularities of the posterior and anterior faces of the lens, and especially of the posterior face, which takes account of the irregular shape of the surface of the eye, it is preferable to provide that the tangent of the profile of the edge of the lens at the point of direct and continuous connection of said profile to the trace of the face concerned in the section plane considered forms with the central axis of reference an angle which varies between a minimum angle and a maximum angle the deviation of which is at least 5 degrees all around the lens.
- the edge of the lens may have, in profile view, a non-planar ridge line.
- the crest line of the edge of the lens it will be preferable for the crest line of the edge of the lens to be such that its orthogonal projection on the central reference axis is a segment having a length of at least 30 ⁇ m corresponding to the minimum height difference between the vertices of this ridge line following the direction of the central reference axis.
- FIG. 1 is a plan view of an ophthalmic lens according to the invention.
- FIG. 1 is a side view of this lens
- FIG. 3 is a sectional view, along the plane III of Figure 1 and corresponding to the detail area III of Figure 2;
- FIG. 4 is a view similar to that of Figure 3, along the plane IV of Figure 1;
- - Figure 5 is a view similar to that of Figure 3, along the plane V of Figure 1;
- - Figure 6 is a view similar to that of Figure 3, along the plane VI of Figure 1;
- FIG. 7 is a view similar to that of Figure 3, along the plane VII of Figure 1;
- FIG. 8 is a view similar to that of Figure 3, along the plane VIII of Figure 1;
- Figure 9 is a view similar to that of Figure 3, along the plane IX of Figure 1;
- - Figure 10 is a view similar to that of Figure 3, along the plane X of Figure 1; and - Figure 11 is a superposition of Figures 4 to 10, where the traces of the edge of the lens in the different planes of section III to X of Figure 1 have been referenced 3 with the corresponding index III to X.
- an ophthalmic lens according to the invention comprises a rear face 1 and a front face 2.
- the rear face 1, of concave shape is intended to come into contact with the 'eye of the wearer, while the front face 2, of convex shape, is intended to come into contact with the eyelid, therefore opposite to the eye.
- the rear face 1 is of any shape, not axisymmetric, that is to say not having a symmetry of revolution.
- This non-axisymmetric shape of the posterior surface 1 results from a customization of the lens carried out in particular from the measurement of the corneal topography of the wearer in such a way that the interface zone between the lens and the cornea is perfectly defined and stabilized.
- the anterior face 2 is in turn determined so as to obtain, in combination with the posterior face shaped as mentioned above in correspondence with the shape of the cornea, the desired optical correction.
- a central reference axis A is defined. This axis can be defined in different ways, among which are will retain in particular those defined below.
- an average radius of curvature of the rear face 1 of the lens is determined and a reference sphere is thus defined having as radius this average radius of curvature and on which the lens can rest by its rear face 1.
- a reference plane on which the edge 3 of the lens rests is then defined as being the line perpendicular to this reference plane passing through the center of the reference sphere defined above.
- the central reference axis A is defined as the perpendicular to the reference plane passing through the center of this circular contour of the edge of The lens.
- the reference plane in question here is the same as that defined previously in the context of the first definition, that is to say the plane on which the edge of the lens rests.
- the central reference axis A can be defined as being coincident with the optical axis of the lens, when the latter can be defined.
- the edge 3 has, in cross section through any plane passing through the central axis of reference A, a profile of constant shape and dimensions on all around the lens.
- the fact that the shape of the lens edge 3 is well determined makes it possible, from a physiological point of view, to ensure good comfort for the wearer and, therefore, better tolerance of the eye with regard to the lens. Consequently, the combination of such an edge 3 of regular profile with the non-axisymmetric shape of the posterior face, adapted to the eye of the wearer, confers on the lens optimal properties both as regards its tolerance by the eye. and as to the effectiveness of the optical correction that it operates.
- the shape and dimensions of the profile of the edge 3 of the lens are defined by any one of FIGS. 3 to 12 which here take the place of description. It can be seen, on examination of these figures, that, in accordance with the essential characteristic of the invention mentioned above, the shape and the dimensions of the profile of the edge 3 of the lens are the same whatever the plane of axial section considered.
- edge 3 is thus, like the rear face 1 (and the front face 2), non-axisymmetric, which makes it possible to optimize, for as natural and direct continuity as possible, the connection of edge 3 to the two faces 1 and 2 of The lens.
- the posterior surface 1 remains entirely defined as a function only of the topographic data of the carrier cornea, without further consideration of connection to the edge 3. It is in fact understood that the presence of a connection area, even localized , on the periphery of the posterior surface 1, defined by considerations of continuity independent of the shape of the cornea, could come into conflict with the cornea and would thus risk being a source of discomfort, or even rejection.
- the continuous connection thus obtained over the entire periphery of the posterior face 1 with the edge 3 makes it possible to avoid the presence of an angular connection line which could, by friction or simple contact, irritate the cornea and could thus be a source of discomfort, even rejection of the lens.
- the edge 3 of the lens is connected to the anterior face 2 by means of d 'a connection leave 4 establishing continuity between the trace of the front face 2 and the profile of the edge 3 in the section plane considered. Thanks to this connection leave, the presence on the periphery of the front face 2 of an angular connection line is avoided which could, by friction or prolonged contact, irritate the eyelid. In addition, this continuity thus imposed on the front face 2 exempts the eyelid from any snag with the lens during its repeated opening and closing movements, which preserves the stability of the positioning of the lens on the eye.
- the shape of the front 2 and rear 1 faces of the lens is imposed by ophthalmic considerations of seating comfort and optical corrections and where the shape and dimensions of the edge profile 3 of the lens are constant and predefined, it is not possible to make a direct and continuous connection of the edge 3 of the lens with the anterior 2 and posterior 1 faces. If it is desired to preserve the lens from any angular zone, it is on the contrary necessary to provide an intermediate connection leave between at least one of the faces of the lens and its edge so to make a continuous transition.
- the posterior surface 1 is that which is intended to come into contact with the cornea and therefore that which is the most sensitive, especially since it is specially conformed to the measured corneal topography.
- connection leave necessary for the continuity of the surface of the lens has been, in the example illustrated, provided on the anterior surface 2 which is only intended to come into contact with the eyelid and which is therefore less sensitive.
- this connection leave occurs only at the periphery of the lens, in the immediate vicinity of the edge 3, outside the optical zone, so that the resulting disturbance in the shape of the anterior surface 2 has no effect on the optical correction made by the lens.
- the general orientation of the profile of the edge 3 of the lens is such that this profile is connects continuously with the trace, in the section plane considered, of the anterior face 2 (instead of a direct and continuous connection to the posterior face 1, as in the embodiment previously described).
- the edge 3 with constant profile intervenes in the immediate extension of the front face 2, without an intermediate connection area.
- This embodiment which preserves the front face 2 from any geometric accident, could in particular be envisaged for lenses intended for people whose eyelids are particularly sensitive and, therefore, prone to eyelid irritation.
- provision may be made as a corollary that, whatever the section plane considered around the central reference axis A, the edge 3 of the lens is connected to the rear face 1 via a connection 4 establishing continuity between the trace of the rear face 1 and the profile of the edge 3 in the section plane considered. Thanks to this connection leave, the presence on the periphery of the posterior face 1 of an angular connection line is avoided which could, by friction or prolonged contact, irritate or even injure the cornea and more generally of s' be a source of discomfort or even rejection.
- the general orientation of the profile of the edge 3 of the lens is an average orientation, resulting from 'A compromise between the two solutions previously exposed in which only one of the two faces of the lens was preferred.
- the profile of the edge 3 of the lens would not connect directly, either to the rear face 1 or to the front face 2, its orientation being intermediate between its two extremes.
- the edge 3 is connected to each of the anterior 2 and posterior 1 faces by means of a connection leave establishing, whatever the plane of section considered around the central reference axis A, a continuity between the profile of the edge 3 on the one hand, and each of the front 2 and rear 1 faces of the lens on the other hand.
- This intermediate solution could be advantageous, in particular in the case of lenses whose front and rear faces have very different geometries from one another.
- the variation of general orientation of the profile of the edge 3 over the entire turn of the lens is such that the tangent of the profile of the edge 3 of the lens at the point of continuous connection of said profile to the trace of the rear face 1 in the section plane considered forms with the central axis of reference To an angle which varies between a minimum angle and a maximum angle the deviation of which is at least 5 degrees over the entire circumference of the lens.
- the aforementioned angle difference is about 15 degrees. More generally, it has been possible to assess during the tests that most cases can be satisfied with an angle deviation of at least 10 degrees.
- the edge 3 of the lens has, seen in plan, an outline of circular shape.
- a crest line 5 which is not planar, that is that is to say which is not inscribed in the reference plane on which its edge can rest.
- crest line 5 is meant the line defined by the set of vertex points in the direction of the central reference axis A of the edge profile 3 in all the section planes passing through the axis AT.
- the crest line 5 of the edge 3 is such that its orthogonal projection on the central reference axis A is a segment 6 having a length d of approximately 500 ⁇ m corresponding to the difference in height between the upper “vertices” and lower of this crest line 5 in the direction of the central reference axis A.
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Abstract
Description
"Lentille ophtalmique de contact à bord régulier". "Ophthalmic contact lens with regular edge".
La présente invention concerne une lentille ophtalmique de contact du type à face postérieure non axisymétrique, c'est-à-dire ne présentant pas une symétrie de révolution.The present invention relates to an ophthalmic contact lens of the non-axisymmetric posterior face type, that is to say that does not have a symmetry of revolution.
On rappelle que la face antérieure d'une lentille de contact est la face convexe de cette lentille qui est opposée à l'œil, tandis que la face postérieure d'une lentille est la face concave de cette lentille qui est au contact de l'œil.It will be recalled that the front face of a contact lens is the convex face of this lens which is opposite to the eye, while the rear face of a lens is the concave face of this lens which is in contact with the eye.
Dans le domaine de la conception des lentilles ophtalmiques de contact, les récents progrès des techniques de mesures fines des différents paramètres oculaires ont ouvert la voie à une personnalisation plus poussée pour une meilleure adaptation de la lentille à l'œil qu'elle corrige. Cette personnalisation peut permettre d'améliorer l'adaptation des lentilles de stock qui sont généralement conçues pour s'adapter à une forme moyenne de l'œil pour une catégorie de porteurs. On peut aussi envisager une personnalisation en quelque sorte "sur mesure", permettant d'adapter la forme de chaque lentille aux caractéristiques mécaniques et optiques de l'œil du porteur auquel elle est destinée. Cette personnalisation, effectuée notamment à partir de la mesure de la topographie coméenne, concerne au premier plan la face postérieure de la lentille qui affecte alors la forme d'une surface complexe non axisymétrique adaptée à la forme de la cornée du porteur de la lentille de manière à maîtriser la zone d'interface entre la lentille et la cornée de l'œil sur lequel elle est rapportée.In the field of ophthalmic contact lens design, recent advances in techniques for fine measurement of different ocular parameters have opened the way for further personalization for better adaptation of the lens to the eye it corrects. This personalization can improve the adaptation of stock lenses which are generally designed to adapt to an average shape of the eye for a category of wearers. One can also consider a customization in a way "tailor-made", allowing to adapt the shape of each lens to the mechanical and optical characteristics of the eye of the wearer for which it is intended. This personalization, carried out in particular from the measurement of the Comean topography, concerns in the foreground the posterior face of the lens which then affects the shape of a complex non-axisymmetric surface adapted to the shape of the cornea of the wearer of the lens. so as to control the interface zone between the lens and the cornea of the eye to which it is attached.
On comprend en effet que la maîtrise de cette zone interface permet d'optimiser le confort du porteur et, partant, sa tolérance envers la lentille.It is indeed understood that the mastery of this interface zone makes it possible to optimize the comfort of the wearer and, consequently, his tolerance towards the lens.
Après que la face postérieure de la lentille a ainsi été conçue pour une interface convenable avec la cornée, la face antérieure de la lentille est déterminée de manière à obtenir, en combinaison avec la face postérieure, la correction optique souhaitée.After the rear face of the lens has thus been designed for a suitable interface with the cornea, the front face of the lens is determined so as to obtain, in combination with the rear face, the desired optical correction.
Les deux faces, antérieure et postérieure, de la lentille étant définies de la sorte, il reste à relier ces deux faces pour former le bord de la lentille.The two faces, anterior and posterior, of the lens being defined in this way, it remains to connect these two faces to form the edge of the lens.
Dans la mesure où les deux faces de la lentille sont non parallèles et non axisymétriques, on aboutit, si l'on se contente de raccorder en périphérie les deux faces de la lentille par une tranche de liaison émoussée, à un bord ayant un profil de forme et de dimensions irrégulières le long du pourtour de la lentille.Insofar as the two faces of the lens are non-parallel and non-axisymmetric, we succeed, if we just connect the periphery two faces of the lens by a blunt connection edge, at an edge having a profile of irregular shape and dimensions along the periphery of the lens.
Dans le document US 5 570 142, par exemple, il est proposé de réaliser une lentille de contact dont la face postérieure est adaptée à la surface irrégulière de la cornée par une correspondance de forme qui peut être complète, sur toute la surface postérieure de la lentille, ou seulement partielle, localisée en périphérie de la lentille, de manière à réaliser une assise stable et régulière de la lentille sur la cornée. Il est clairement précisé dans ce document que, du fait de la forme asymétrique et asphérique de la face postérieure de la lentille, son bord présente nécessairement un profil de forme et de dimensions irrégulières.In document US 5,570,142, for example, it is proposed to produce a contact lens whose posterior face is adapted to the irregular surface of the cornea by a shape correspondence which can be complete, over the entire posterior surface of the lens, or only partial, located at the periphery of the lens, so as to achieve a stable and regular seating of the lens on the cornea. It is clearly specified in this document that, because of the asymmetrical and aspherical shape of the posterior face of the lens, its edge necessarily has a profile of irregular shape and dimensions.
De même, le document US 5 880 809 décrit une lentille de contact dont la face postérieure vient en correspondance avec la surface de la cornée et dont le bord présente un profil circulaire dont le rayon varie le long du pourtour de la lentille, tout en restant supérieur à un rayon minimum prédéterminé (voir colonneLikewise, document US Pat. No. 5,880,809 describes a contact lens whose posterior face comes into correspondence with the surface of the cornea and whose edge has a circular profile whose radius varies along the periphery of the lens, while remaining greater than a predetermined minimum radius (see column
12 ligne 8 et suivantes de ce document).12 line 8 and following of this document).
Le document US 5 452 031 décrit également une lentille de contact dont le bord est défini en fonction de la forme de la surface de la cornée, de manière à améliorer le confort du porteur en favorisant les échanges de liquide lacrymal. Mais le fait que le bord de lentille soit optimisé en fonction de la forme particulière de la cornée du porteur est indépendant du caractère régulier ou irrégulier de ce bord. Or aucune disposition particulière n'est prévue en ce qui concerne la régularité du bord de lentille, de sorte que dans l'hypothèse où la face postérieure de la lentille est non axisymétrique pour être adaptée à la surface de la cornée, on aboutit immanquablement à un bord de lentille ayant un profil irrégulier.The document US Pat. No. 5,452,031 also describes a contact lens whose edge is defined as a function of the shape of the surface of the cornea, so as to improve the comfort of the wearer by promoting exchanges of lacrimal fluid. However, the fact that the lens edge is optimized as a function of the particular shape of the wearer's cornea is independent of the regular or irregular nature of this edge. However, no particular provision is made with regard to the regularity of the lens edge, so that in the event that the posterior face of the lens is non-axisymmetric to be adapted to the surface of the cornea, it inevitably leads to a lens edge having an irregular profile.
Selon l'invention, on propose une lentille ophtalmique de contact à face postérieure non axisymétrique, cette lentille possédant un bord présentant, en section transversale par tout plan passant par un axe central de référence de la lentille, un profil de forme et dimensions constantes sur tout le tour de la lentille.According to the invention, an ophthalmic contact lens with a non-axisymmetric rear face is proposed, this lens having an edge having, in cross section through any plane passing through a central reference axis of the lens, a profile of constant shape and dimensions over all around the lens.
Le fait que la forme du bord de lentille soit bien déterminée permet, d'un point de vue physiologique, d'assurer un bon confort du porteur et, partant, une meilleure tolérance de l'œil à l'égard de la lentille. Par conséquent, la combinaison d'un tel bord de profil régulier avec la forme non axisymétrique de la face postérieure, adaptée à l'œil du porteur, confère à la lentille des propriétés optimales à la fois quant à sa tolérance par l'œil et quant à l'efficacité de la correction optique qu'elle opère. Selon une première caractéristique avantageuse de l'invention, l'orientation générale du profil du bord de la lentille dans son plan de section varie par rapport à l'axe central de référence en fonction du plan de section considéré autour de cet axe. On obtient ainsi un bord de lentille qui, comme la face postérieure, est non axisymétrique, mais qui conserve en revanche un profil de forme et de dimensions parfaitement régulières et maîtrisées. Cette variation de l'orientation générale du profil du bord de la lentille permet d'optimiser le raccordement du bord de lentille aux faces postérieure et antérieure de cette lentille. On comprend en effet que ces deux faces sont par définition irrégulières et présentent de ce fait, en section transversale par un plan passant par l'axe central de référence de la lentille, une tangente de raccordement au bord de la lentille qui forme, par rapport à cet axe de référence, un angle variable sur tout le tour de la lentille.The fact that the shape of the lens edge is well determined makes it possible, from a physiological point of view, to ensure good comfort for the wearer and, consequently, better tolerance of the eye with regard to the lens. Therefore, the combination of such a regular profile edge with the non-axisymmetric shape of the posterior face, adapted to the wearer's eye, gives the lens optimal properties both in terms of its tolerance by the eye and in terms of effectiveness of the optical correction it operates. According to a first advantageous characteristic of the invention, the general orientation of the profile of the edge of the lens in its section plane varies with respect to the central reference axis as a function of the section plane considered around this axis. A lens edge is thus obtained which, like the rear face, is not axisymmetric, but which on the other hand retains a profile of perfectly regular and controlled shape and dimensions. This variation in the general orientation of the profile of the edge of the lens makes it possible to optimize the connection of the edge of the lens to the posterior and anterior faces of this lens. It is in fact understood that these two faces are by definition irregular and therefore have, in cross section through a plane passing through the central reference axis of the lens, a tangent of connection at the edge of the lens which forms, with respect to at this reference axis, a variable angle over the entire turn of the lens.
En particulier, il est avantageux de prévoir que, quel que soit le plan de section considéré autour de l'axe central de référence, l'orientation générale du profil du bord de la lentille est telle que ce profil se raccorde de manière continue avec la trace, dans le plan de section considéré, de l'une des faces postérieure et antérieure de la lentille et dans le prolongement immédiat de cette face, sans zone de raccordement intermédiaire. On évite ainsi la présence, dans la zone de raccordement de la face postérieure de la lentille au bord de cette lentille, d'une ligne anguleuse qui risquerait, par frottement ou simple contact, d'irriter la cornée et pourrait ainsi s'avérer source d'inconfort, voire de rejet de la lentille. De plus, la face postérieure de la lentille reste intégralement définie en fonction de la cornée, sans zone de raccordement au bord qui pourrait s'avérer source d'inconfort De même, en combinaison avec le raccordement direct et continu de la face postérieure, il pourra être avantageux de prévoir que le bord de la lentille se raccorde à l'autre de ces faces par l'intermédiaire d'un congé de raccordement établissant, quel que soit le plan de section considéré autour de l'axe central de référence, une continuité entre la trace de cette autre face et le profil du bord de la lentille dans le plan de section considéré. On préserve ainsi la paupière de tout contact ou frottement irritant avec une zone de raccordement anguleuse de la face antérieure au bord de la lentille. De manière différente, il peut aussi être avantageux, notamment dans les cas où les deux faces de la lentille présentent des géométries très différentes l'une de l'autre, de prévoir que le bord de la lentille se raccorde à chacune des faces antérieure et postérieure de la lentille par l'intermédiaire d'un congé de raccordement établissant, quel que soit le plan de section considéré autour de l'axe central de référence, une continuité entre le profil du bord de la lentille et chacune des traces des faces antérieure et postérieure de la lentille dans le plan de section considéréIn particular, it is advantageous to provide that, whatever the section plane considered around the central reference axis, the general orientation of the profile of the edge of the lens is such that this profile is connected continuously with the trace, in the section plane considered, of one of the posterior and anterior faces of the lens and in the immediate extension of this face, without an intermediate connection zone. This avoids the presence, in the connection area of the rear face of the lens at the edge of this lens, of an angular line which could, by friction or simple contact, irritate the cornea and could thus prove to be a source discomfort or even rejection of the lens. In addition, the posterior surface of the lens remains fully defined as a function of the cornea, with no connection zone at the edge which could prove to be a source of discomfort. Similarly, in combination with the direct and continuous connection of the posterior surface, it may be advantageous to provide that the edge of the lens is connected to the other of these faces by means of a connection leave establishing, whatever the section plane considered around the central axis of reference, continuity between the trace of this other face and the profile of the edge of the lens in the section plane considered. This protects the eyelid from any irritating contact or friction with an angular connection zone from the anterior surface to the edge of the lens. In a different way, it can also be advantageous, in particular in the cases where the two faces of the lens have very different geometries from each other, to provide that the edge of the lens is connected to each of the front faces and posterior of the lens by means of a connection leave establishing, whatever the section plane considered around the central reference axis, continuity between the profile of the edge of the lens and each of the traces of the anterior faces and posterior of the lens in the section plane considered
Quoi qu'il en soit, pour une adaptation suffisante du bord de la lentille aux irrégularités des faces postérieure et antérieure de la lentille, et surtout de la face postérieure, qui tient compte de la forme irrégulière de la surface de l'œil, il est préférable de prévoir que la tangente du profil du bord de la lentille au point de raccordement direct et continu dudit profil à la trace de la face concernée dans le plan de section considéré forme avec l'axe central de référence un angle qui varie entre un angle minimum et un angle maximum dont l'écart est d'au moins 5 degrés sur tout le tour de la lentille.Anyway, for a sufficient adaptation of the edge of the lens to the irregularities of the posterior and anterior faces of the lens, and especially of the posterior face, which takes account of the irregular shape of the surface of the eye, it it is preferable to provide that the tangent of the profile of the edge of the lens at the point of direct and continuous connection of said profile to the trace of the face concerned in the section plane considered forms with the central axis of reference an angle which varies between a minimum angle and a maximum angle the deviation of which is at least 5 degrees all around the lens.
Par ailleurs, toujours dans le souci de permettre un raccordement aussi continu que possible, et avec un maximum de régularité, de la face postérieure de la lentille avec son bord, on pourra prévoir que le bord de la lentille possède, vue de profil, une ligne de crête qui n'est pas plane. En pratique, il sera préférable que la ligne de crête du bord de la lentille soit telle que sa projection orthogonale sur l'axe central de référence soit un segment présentant une longueur d'au moins 30 μm correspondant au dénivelé minimum entre les sommets de cette ligne de crête suivant la direction de l'axe central de référence. D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description qui suit d'un mode de réalisation particulier donné à titre d'exemple non limitatif.Furthermore, still with the aim of allowing as continuous a connection as possible, and with a maximum of regularity, of the rear face of the lens with its edge, provision may be made for the edge of the lens to have, in profile view, a non-planar ridge line. In practice, it will be preferable for the crest line of the edge of the lens to be such that its orthogonal projection on the central reference axis is a segment having a length of at least 30 μm corresponding to the minimum height difference between the vertices of this ridge line following the direction of the central reference axis. Other characteristics and advantages of the invention will appear on reading the following description of a particular embodiment given by way of non-limiting example.
Il sera fait référence aux dessins en annexe parmi lesquels : - la figure 1 est une vue en plan d'une lentille ophtalmique conforme à l'invention ;Reference will be made to the accompanying drawings, among which: - Figure 1 is a plan view of an ophthalmic lens according to the invention;
- la figure 2 est une vue de profil de cette lentille ;- Figure 2 is a side view of this lens;
- la figure 3 est une vue en coupe, selon le plan III de la figure 1 et correspondant à la zone de détail III de la figure 2 ;- Figure 3 is a sectional view, along the plane III of Figure 1 and corresponding to the detail area III of Figure 2;
- la figure 4 est une vue analogue à celle de la figure 3, selon le plan IV de la figure 1 ;- Figure 4 is a view similar to that of Figure 3, along the plane IV of Figure 1;
- la figure 5 est une vue analogue à celle de la figure 3, selon le plan V de la figure 1 ; - la figure 6 est une vue analogue à celle de la figure 3, selon le plan VI de la figure 1 ;- Figure 5 is a view similar to that of Figure 3, along the plane V of Figure 1; - Figure 6 is a view similar to that of Figure 3, along the plane VI of Figure 1;
- la figure 7 est une vue analogue à celle de la figure 3, selon le plan VII de la figure 1 ;- Figure 7 is a view similar to that of Figure 3, along the plane VII of Figure 1;
- la figure 8 est une vue analogue à celle de la figure 3, selon le plan VIII de la figure 1 ;- Figure 8 is a view similar to that of Figure 3, along the plane VIII of Figure 1;
- la figure 9 est une vue analogue à celle de la figure 3, selon le plan IX de la figure 1 ;- Figure 9 is a view similar to that of Figure 3, along the plane IX of Figure 1;
- la figure 10 est une vue analogue à celle de la figure 3, selon le plan X de la figure 1 ; et - la figure 11 est une superposition des figures 4 à 10, où les traces du bord de la lentille dans les différents plans de section III à X de la figure 1 ont été référencés 3 avec l'indice correspondant III à X.- Figure 10 is a view similar to that of Figure 3, along the plane X of Figure 1; and - Figure 11 is a superposition of Figures 4 to 10, where the traces of the edge of the lens in the different planes of section III to X of Figure 1 have been referenced 3 with the corresponding index III to X.
En référence aux figures, et en particulier aux figures 1 et 2, une lentille ophtalmique conforme à l'invention comporte une face postérieure 1 et une face antérieure 2. La face postérieure 1 , de forme concave, est destinée à venir au contact de l'œil du porteur, tandis que la face antérieure 2, de forme convexe, est destinée à venir au contact de la paupière, par conséquent à l'opposé de l'œil.With reference to the figures, and in particular to Figures 1 and 2, an ophthalmic lens according to the invention comprises a rear face 1 and a front face 2. The rear face 1, of concave shape, is intended to come into contact with the 'eye of the wearer, while the front face 2, of convex shape, is intended to come into contact with the eyelid, therefore opposite to the eye.
La face postérieure 1 est de forme quelconque, non axisymétrique, c'est-à-dire ne présentant pas une symétrie de révolution. Cette forme non axisymétrique de la face postérieure 1 résulte d'une personnalisation de la lentille effectuée notamment à partir de la mesure de la topographie cornéenne du porteur de telle manière que la zone d'interface entre la lentille et la cornée soit parfaitement définie et stabilisée.The rear face 1 is of any shape, not axisymmetric, that is to say not having a symmetry of revolution. This non-axisymmetric shape of the posterior surface 1 results from a customization of the lens carried out in particular from the measurement of the corneal topography of the wearer in such a way that the interface zone between the lens and the cornea is perfectly defined and stabilized.
On peut notamment aboutir à une face postérieure 1 de forme essentiellement torique. La face antérieure 2 est quant à elle déterminée de manière à obtenir, en combinaison avec la face postérieure conformée comme mentionné ci-dessus en correspondance avec la forme de la cornée, la correction optique souhaitée.One can in particular end up with a rear face 1 of essentially toroidal shape. The anterior face 2 is in turn determined so as to obtain, in combination with the posterior face shaped as mentioned above in correspondence with the shape of the cornea, the desired optical correction.
A la périphérie de la lentille, les faces postérieure 1 et antérieure 2 se raccordent par un bord 3. A des fins de commodité de repérage, on définit un axe central de référence A. Cet axe peut être défini de différentes manières, parmi lesquelles on retiendra en particulier celles définies ci-après.At the periphery of the lens, the posterior 1 and anterior 2 faces are connected by an edge 3. For convenience of location, a central reference axis A is defined. This axis can be defined in different ways, among which are will retain in particular those defined below.
Selon une première définition, on détermine un rayon de courbure moyen de la face postérieure 1 de la lentille et on définit ainsi une sphère de référence ayant pour rayon ce rayon de courbure moyen et sur laquelle la lentille peut reposer par sa face postérieure 1. On définit également un plan de référence sur lequel le bord 3 de la lentille repose. L'axe central de référence A est alors défini comme étant la droite perpendiculaire à ce plan de référence passant par le centre de la sphère de référence ci-dessus définie. Selon une seconde définition, valable uniquement lorsque le bord de la lentille présente, vu en plan, un contour circulaire, l'axe central de référence A est défini comme la perpendiculaire au plan de référence passant par le centre de ce contour circulaire du bord de la lentille. Le plan de référence dont il est ici question est le même que celui défini précédemment dans le cadre de la première définition, c'est-à-dire le plan sur lequel le bord de la lentille repose.According to a first definition, an average radius of curvature of the rear face 1 of the lens is determined and a reference sphere is thus defined having as radius this average radius of curvature and on which the lens can rest by its rear face 1. On also defines a reference plane on which the edge 3 of the lens rests. The central reference axis A is then defined as being the line perpendicular to this reference plane passing through the center of the reference sphere defined above. According to a second definition, valid only when the edge of the lens has, seen in plan, a circular contour, the central reference axis A is defined as the perpendicular to the reference plane passing through the center of this circular contour of the edge of The lens. The reference plane in question here is the same as that defined previously in the context of the first definition, that is to say the plane on which the edge of the lens rests.
Enfin, selon une troisième définition, l'axe central de référence A peut être défini comme étant confondu avec l'axe optique de la lentille, quand celui-ci peut être défini.Finally, according to a third definition, the central reference axis A can be defined as being coincident with the optical axis of the lens, when the latter can be defined.
Comme cela est visible par le rapprochement des figures 3 à 10 ainsi qu'à la figure 11 , le bord 3 présente, en section transversale par tout plan passant par l'axe central de référence A, un profil de forme et de dimensions constantes sur tout le tour de la lentille. Le fait que la forme du bord 3 de lentille soit bien déterminée permet, d'un point de vue physiologique, d'assurer un bon confort du porteur et, partant, une meilleure tolérance de l'œil à l'égard de la lentille. Par conséquent, la combinaison d'un tel bord 3 de profil régulier avec la forme non axisymétrique de la face postérieure, adaptée à l'œil du porteur, confère à la lentille des propriétés optimales à la fois quant à sa tolérance par l'œil et quant à l'efficacité de la correction optique qu'elle opère.As can be seen by the comparison of Figures 3 to 10 and in Figure 11, the edge 3 has, in cross section through any plane passing through the central axis of reference A, a profile of constant shape and dimensions on all around the lens. The fact that the shape of the lens edge 3 is well determined makes it possible, from a physiological point of view, to ensure good comfort for the wearer and, therefore, better tolerance of the eye with regard to the lens. Consequently, the combination of such an edge 3 of regular profile with the non-axisymmetric shape of the posterior face, adapted to the eye of the wearer, confers on the lens optimal properties both as regards its tolerance by the eye. and as to the effectiveness of the optical correction that it operates.
Plus précisément, la forme et les dimensions du profil du bord 3 de la lentille sont définies par l'une quelconque des figures 3 à 12 qui tiennent ici lieu de description. On constate en effet, à l'examen de ces figures, que, conformément à la caractéristique essentielle de l'invention mentionnée ci- dessus, la forme et les dimensions du profil du bord 3 de la lentille sont les mêmes quel que soit le plan de section axial considéré.More specifically, the shape and dimensions of the profile of the edge 3 of the lens are defined by any one of FIGS. 3 to 12 which here take the place of description. It can be seen, on examination of these figures, that, in accordance with the essential characteristic of the invention mentioned above, the shape and the dimensions of the profile of the edge 3 of the lens are the same whatever the plane of axial section considered.
Comme cela est visible en particulier à la figure 11 , seules varient par rapport à l'axe central de référence A l'orientation générale et la position du profil du bord 3 en fonction du plan de section considéré autour de l'axe A. Le bord 3 est ainsi, comme la face postérieure 1 (et la face antérieure 2), non axisymétrique, ce qui permet d'optimiser, pour une continuité aussi naturelle et directe que possible, le raccordement du bord 3 aux deux faces 1 et 2 de la lentille.As can be seen in particular in FIG. 11, only they vary with respect to the central axis of reference to the general orientation and the position of the profile of the edge 3 as a function of the section plane considered around the axis A. edge 3 is thus, like the rear face 1 (and the front face 2), non-axisymmetric, which makes it possible to optimize, for as natural and direct continuity as possible, the connection of edge 3 to the two faces 1 and 2 of The lens.
Pour la vue de profil de la figure 2 et pour les différentes vues en coupe des figures 2 à 10, il a été défini des référentiels analogues ayant chacun pour origine le point O situé à l'intersection de l'axe central de référence A et de la face antérieure 2, pour axe des ordonnées l'axe A et pour axe des abscisses la perpendiculaire à l'axe A située dans le plan de section considéré. L'origine O et l'axe A des ordonnées sont donc communs à tous ces référentiels. Des graduations en millimètres ont été portées sur chacun de ces référentiels. On notera d'ailleurs que les différentes coupes des figures 3 à 10 sont toutes à la même échelle. Il en est de même de la figure 11 qui reprend, superposées, ces différentes coupes.For the profile view of FIG. 2 and for the various sectional views of FIGS. 2 to 10, similar reference frames have been defined, each originating from the point O situated at the intersection of the central reference axis A and of the anterior face 2, for the ordinate axis the axis A and for the abscissa axis the perpendicular to the axis A located in the plane of section considered. The origin O and the axis A of the ordinates are therefore common to all these reference frames. Graduations in millimeters have been shown on each of these standards. Note also that the different sections of Figures 3 to 10 are all on the same scale. The same is true of FIG. 11 which shows, superimposed, these different sections.
Comme cela est visible par le rapprochement des figures 3 à 10 ainsi qu'à la figure 11 , quel que soit le plan de section considéré autour de l'axe central de référence A, l'orientation générale du profil du bord 3 de la lentille est telle que ce profil se raccorde de manière continue avec la trace, dans le plan de section considéré, de la face postérieure 1. Ce raccordement continu de la face postérieure 1 au bord 3 est direct : le bord 3 à profil constant en forme et en dimensions intervient dans le prolongement immédiat de la face postérieure 1 , sans zone de raccordement intermédiaire.As can be seen by the comparison of FIGS. 3 to 10 as well as in FIG. 11, whatever the section plane considered around the central reference axis A, the general orientation of the profile of the edge 3 of the lens East such that this profile is connected continuously with the trace, in the section plane considered, of the rear face 1. This continuous connection of the rear face 1 to the edge 3 is direct: the edge 3 with a constant profile in shape and in dimensions intervenes in the immediate extension of the rear face 1, without an intermediate connection zone.
Grâce à un tel raccordement direct, la face postérieure 1 reste intégralement définie en fonction des seules données topographiques de la cornée porteuse, sans autre considération de raccordement au bord 3. On comprend en effet que la présence d'une zone de raccordement, même localisée, en périphérie de la face postérieure 1 , définie par des considérations de continuité indépendantes de la forme de la cornée, pourrait rentrer en conflit avec la cornée et risquerait ainsi de s'avérer une source d'inconfort, voire de rejet. De plus, le raccordement continu ainsi obtenu sur toute la périphérie de la face postérieure 1 avec le bord 3 permet d'éviter la présence d'une ligne anguleuse de raccordement qui risquerait, par frottement ou simple contact, d'irriter la cornée et pourrait ainsi s'avérer source d'inconfort, voire de rejet de la lentille.Thanks to such a direct connection, the posterior surface 1 remains entirely defined as a function only of the topographic data of the carrier cornea, without further consideration of connection to the edge 3. It is in fact understood that the presence of a connection area, even localized , on the periphery of the posterior surface 1, defined by considerations of continuity independent of the shape of the cornea, could come into conflict with the cornea and would thus risk being a source of discomfort, or even rejection. In addition, the continuous connection thus obtained over the entire periphery of the posterior face 1 with the edge 3 makes it possible to avoid the presence of an angular connection line which could, by friction or simple contact, irritate the cornea and could thus be a source of discomfort, even rejection of the lens.
De plus, comme cela est également visible aux figures 2 à 10, quel que soit le plan de section considéré autour de l'axe central de référence A, le bord 3 de la lentille se raccorde à la face antérieure 2 par l'intermédiaire d'un congé de raccordement 4 établissant une continuité entre la trace de la face antérieure 2 et le profil du bord 3 dans le plan de section considéré. Grâce à ce congé de raccordement, on évite la présence en périphérie de la face antérieure 2 d'une ligne anguleuse de raccordement qui risquerait, par frottement ou contact prolongé, d'irriter la paupière. De plus, cette continuité ainsi imposée de la face antérieure 2 exempte la paupière de tout accroc avec la lentille lors de ses mouvements d'ouverture et de fermeture répétés, ce qui préserve la stabilité du positionnement de la lentille sur l'œil.In addition, as is also visible in FIGS. 2 to 10, whatever the section plane considered around the central reference axis A, the edge 3 of the lens is connected to the anterior face 2 by means of d 'a connection leave 4 establishing continuity between the trace of the front face 2 and the profile of the edge 3 in the section plane considered. Thanks to this connection leave, the presence on the periphery of the front face 2 of an angular connection line is avoided which could, by friction or prolonged contact, irritate the eyelid. In addition, this continuity thus imposed on the front face 2 exempts the eyelid from any snag with the lens during its repeated opening and closing movements, which preserves the stability of the positioning of the lens on the eye.
On notera par ailleurs que, dans la mesure où la forme des faces antérieure 2 et postérieure 1 de la lentille est imposée par des considérations ophtalmiques de confort d'assise et de corrections optiques et où la forme et les dimensions du profil du bord 3 de la lentille sont constantes et prédéfinies, il n'est pas possible de réaliser un raccordement direct et continu du bord 3 de la lentille avec les faces antérieure 2 et postérieure 1. Si l'on souhaite préserver la lentille de toute zone anguleuse, il est au contraire nécessaire de prévoir un congé de raccordement intermédiaire entre au moins l'une des faces de la lentille et son bord de manière à réaliser une transition continue. Or, la face postérieure 1 est celle qui est destinée à venir au contact de la cornée et donc celle qui est la plus sensible, d'autant qu'elle est spécialement conformée à la topographie cornéenne mesurée. Il est donc du plus grand intérêt de préserver l'intégrité de cette face postérieure 1. C'est la raison pour laquelle le congé de raccordement nécessaire à la continuité de la surface de la lentille a été, dans l'exemple illustré, prévu sur la face antérieure 2 qui est seulement destinée à venir au contact de la paupière et qui est de ce fait moins sensible. En outre, ce congé de raccordement n'intervient qu'en périphérie de la lentille, à proximité immédiate du bord 3, en dehors de la zone optique, si bien que la perturbation qui en résulte dans la forme de la face antérieure 2 n'a aucune incidence sur la correction optique opérée par la lentille.It will also be noted that, insofar as the shape of the front 2 and rear 1 faces of the lens is imposed by ophthalmic considerations of seating comfort and optical corrections and where the shape and dimensions of the edge profile 3 of the lens are constant and predefined, it is not possible to make a direct and continuous connection of the edge 3 of the lens with the anterior 2 and posterior 1 faces. If it is desired to preserve the lens from any angular zone, it is on the contrary necessary to provide an intermediate connection leave between at least one of the faces of the lens and its edge so to make a continuous transition. However, the posterior surface 1 is that which is intended to come into contact with the cornea and therefore that which is the most sensitive, especially since it is specially conformed to the measured corneal topography. It is therefore of the greatest interest to preserve the integrity of this rear face 1. This is the reason why the connection leave necessary for the continuity of the surface of the lens has been, in the example illustrated, provided on the anterior surface 2 which is only intended to come into contact with the eyelid and which is therefore less sensitive. In addition, this connection leave occurs only at the periphery of the lens, in the immediate vicinity of the edge 3, outside the optical zone, so that the resulting disturbance in the shape of the anterior surface 2 has no effect on the optical correction made by the lens.
Toutefois, dans un autre mode de réalisation, on pourrait prévoir que, quel que soit le plan de section considéré autour de l'axe central de référence A, l'orientation générale du profil du bord 3 de la lentille est telle que ce profil se raccorde de manière continue avec la trace, dans le plan de section considéré, de la face antérieure 2 (au lieu d'un raccordement direct et continu à la face postérieure 1 , comme dans le mode de réalisation précédemment décrit). A l'instar du mode de réalisation précédemment décrit où ce raccordement continu de la face postérieure 1 au bord 3 est direct, le bord 3 à profil constant intervient dans le prolongement immédiat de la face antérieure 2, sans zone de raccordement intermédiaire.However, in another embodiment, it could be provided that, whatever the section plane considered around the central reference axis A, the general orientation of the profile of the edge 3 of the lens is such that this profile is connects continuously with the trace, in the section plane considered, of the anterior face 2 (instead of a direct and continuous connection to the posterior face 1, as in the embodiment previously described). Like the embodiment described above where this continuous connection of the rear face 1 to the edge 3 is direct, the edge 3 with constant profile intervenes in the immediate extension of the front face 2, without an intermediate connection area.
Ce mode de réalisation, qui préserve la face antérieure 2 de tout accident géométrique, pourrait en particulier être envisagé pour des lentilles destinées à des personnes dont les paupières sont particulièrement sensibles et, partant, sujettes à une irritation palpébrale. Dans ce cas, on pourra prévoir corollairement que, quel que soit le plan de section considéré autour de l'axe central de référence A, le bord 3 de la lentille se raccorde à la face postérieure 1 par l'intermédiaire d'un congé de raccordement 4 établissant une continuité entre la trace de la face postérieure 1 et le profil du bord 3 dans le plan de section considéré. Grâce à ce congé de raccordement, on évite la présence en périphérie de la face postérieure 1 d'une ligne anguleuse de raccordement qui risquerait, par frottement ou contact prolongé, d'irriter, voire de blesser, la cornée et plus généralement de s'avérer une source d'inconfort, voire de rejet.This embodiment, which preserves the front face 2 from any geometric accident, could in particular be envisaged for lenses intended for people whose eyelids are particularly sensitive and, therefore, prone to eyelid irritation. In this case, provision may be made as a corollary that, whatever the section plane considered around the central reference axis A, the edge 3 of the lens is connected to the rear face 1 via a connection 4 establishing continuity between the trace of the rear face 1 and the profile of the edge 3 in the section plane considered. Thanks to this connection leave, the presence on the periphery of the posterior face 1 of an angular connection line is avoided which could, by friction or prolonged contact, irritate or even injure the cornea and more generally of s' be a source of discomfort or even rejection.
Dans encore un autre mode de réalisation, on pourrait prévoir que, quel que soit le plan de section considéré autour de l'axe central de référence A, l'orientation générale du profil du bord 3 de la lentille soit une orientation moyenne, résultant d'un compromis entre les deux solutions précédemment exposées dans lesquelles une seule des deux faces de la lentille était privilégiée.In yet another embodiment, it could be provided that, whatever the section plane considered around the central reference axis A, the general orientation of the profile of the edge 3 of the lens is an average orientation, resulting from 'A compromise between the two solutions previously exposed in which only one of the two faces of the lens was preferred.
Dans ce mode de réalisation en effet, le profil du bord 3 de la lentille ne se raccorderait directement, ni à la face postérieure 1 ni à la face antérieure 2, son orientation étant intermédiaire entre ses deux extrêmes. Pour assurer la continuité du bord 3 avec les faces antérieure 2 et postérieure 1 , on prévoirait que le bord 3 se raccorde à chacune des faces antérieure 2 et postérieure 1 par l'intermédiaire d'un congé de raccordement établissant, quel que soit le plan de section considéré autour de l'axe central de référence A, une continuité entre le profil du bord 3 d'une part, et chacune des faces antérieure 2 et postérieure 1 de la lentille d'autre part. Cette solution intermédiaire pourrait être avantageuse, en particulier dans le cas de lentilles dont les faces antérieure et postérieure présentent des géométries très différentes l'une de l'autre. Le choix d'une orientation moyenne du profil du bord de la lentille combiné à la présence d'un congé de raccordement de ce bord avec chacune des deux faces permettrait, dans ce cas particulier, de préserver autant que possible les deux faces à la fois pour un meilleur confort et une meilleure tolérance du porteur.In this embodiment, in fact, the profile of the edge 3 of the lens would not connect directly, either to the rear face 1 or to the front face 2, its orientation being intermediate between its two extremes. To ensure the continuity of the edge 3 with the anterior 2 and posterior 1 faces, it would be provided that the edge 3 is connected to each of the anterior 2 and posterior 1 faces by means of a connection leave establishing, whatever the plane of section considered around the central reference axis A, a continuity between the profile of the edge 3 on the one hand, and each of the front 2 and rear 1 faces of the lens on the other hand. This intermediate solution could be advantageous, in particular in the case of lenses whose front and rear faces have very different geometries from one another. The choice of an average orientation of the profile of the edge of the lens combined with the presence of a leave of connection of this edge with each of the two faces would, in this particular case, make it possible to preserve as much as possible the two faces at the same time for better comfort and better wearer tolerance.
Quoi qu'il en soit, pour une adaptation suffisante du bord 3 de la lentille aux irrégularités des faces postérieure 1 et antérieure 2, et surtout de la face postérieure 1 , il est préférable que la variation d'orientation générale du profil du bord 3 sur tout le tour de la lentille soit telle que la tangente du profil du bord 3 de la lentille au point de raccordement continu dudit profil à la trace de la face postérieure 1 dans le plan de section considéré forme avec l'axe central de référence A un angle qui varie entre un angle minimum et un angle maximum dont l'écart est d'au moins 5 degrés sur tout le tour de la lentille.Anyway, for a sufficient adaptation of the edge 3 of the lens to the irregularities of the posterior 1 and anterior 2 faces, and especially of the posterior face 1, it is preferable that the variation of general orientation of the profile of the edge 3 over the entire turn of the lens is such that the tangent of the profile of the edge 3 of the lens at the point of continuous connection of said profile to the trace of the rear face 1 in the section plane considered forms with the central axis of reference To an angle which varies between a minimum angle and a maximum angle the deviation of which is at least 5 degrees over the entire circumference of the lens.
En l'espèce, et comme cela peut être mesuré sur les figures 3 à 10, l'écart d'angle précité est d'environ 15 degrés. De manière plus générale, on a pu évaluer aux essais que la plupart des cas pourront être satisfaits avec un écart d'angle d'au moins 10 degrés.In this case, and as can be measured in Figures 3 to 10, the aforementioned angle difference is about 15 degrees. More generally, it has been possible to assess during the tests that most cases can be satisfied with an angle deviation of at least 10 degrees.
Dans l'exemple illustré aux figures, et comme cela est mieux visible sur la figure 1 , le bord 3 de la lentille présente, vu en plan, un contour de forme circulaire. Dans ce cas, il résulte de la forme non axisymétrique de la face postérieure 1 que la lentille présente, vue de profil, comme cela est mieux visible à la figure 2, une ligne de crête 5 qui n'est pas plane, c'est-à-dire qui n'est pas inscrite dans le plan de référence sur lequel son bord peut reposer. On comprend que, par ligne de crête 5, on entend la ligne définie par l'ensemble des points de sommet suivant la direction de l'axe central de référence A du profil du bord 3 dans tous les plans de section passant par l'axe A.In the example illustrated in the figures, and as is better visible in FIG. 1, the edge 3 of the lens has, seen in plan, an outline of circular shape. In this case, it results from the non-axisymmetric shape of the rear face 1 that the lens has, seen in profile, as is better visible in FIG. 2, a crest line 5 which is not planar, that is that is to say which is not inscribed in the reference plane on which its edge can rest. It is understood that, by crest line 5, is meant the line defined by the set of vertex points in the direction of the central reference axis A of the edge profile 3 in all the section planes passing through the axis AT.
En l'espèce, la ligne de crête 5 du bord 3 est telle que sa projection orthogonale sur l'axe central de référence A est un segment 6 ayant une longueur d d'environ 500 μm correspondant au dénivelé entre les "sommets" supérieur et inférieur de cette ligne de crête 5 suivant la direction de l'axe central de référence A.In this case, the crest line 5 of the edge 3 is such that its orthogonal projection on the central reference axis A is a segment 6 having a length d of approximately 500 μm corresponding to the difference in height between the upper "vertices" and lower of this crest line 5 in the direction of the central reference axis A.
De manière plus générale, on obtiendra des résultats satisfaisants dans la plupart des cas avec un dénivelé d compris entre 100 et 1000 μm et en tout état de cause il sera préférable de prévoir un dénivelé d'au moins 30 μm. More generally, satisfactory results will be obtained in most cases with an elevation difference of between 100 and 1000 μm and in any event it will be preferable to provide for an elevation of at least 30 μm.
Claims
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2001286004A AU2001286004A1 (en) | 2000-08-23 | 2001-08-23 | Ophthalmic contact lens with uniform edge |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR0010861A FR2813399A1 (en) | 2000-08-23 | 2000-08-23 | OPHTHALMIC CONTACT LENS WITH REGULAR EDGE |
| FR00/10861 | 2000-08-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2002017001A1 true WO2002017001A1 (en) | 2002-02-28 |
Family
ID=8853684
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FR2001/002658 Ceased WO2002017001A1 (en) | 2000-08-23 | 2001-08-23 | Ophthalmic contact lens with uniform edge |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2001286004A1 (en) |
| FR (1) | FR2813399A1 (en) |
| WO (1) | WO2002017001A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5452031A (en) * | 1993-05-05 | 1995-09-19 | Boston Eye Technology, Inc. | Contact lens and a method for manufacturing contact lens |
| US5570142A (en) * | 1993-09-09 | 1996-10-29 | Scientific Optics, Inc. | Asymmetric aspheric contact lens |
| US5880809A (en) * | 1996-12-30 | 1999-03-09 | Scientific Optics, Inc. | Contact lens |
-
2000
- 2000-08-23 FR FR0010861A patent/FR2813399A1/en not_active Withdrawn
-
2001
- 2001-08-23 WO PCT/FR2001/002658 patent/WO2002017001A1/en not_active Ceased
- 2001-08-23 AU AU2001286004A patent/AU2001286004A1/en not_active Abandoned
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5452031A (en) * | 1993-05-05 | 1995-09-19 | Boston Eye Technology, Inc. | Contact lens and a method for manufacturing contact lens |
| US5570142A (en) * | 1993-09-09 | 1996-10-29 | Scientific Optics, Inc. | Asymmetric aspheric contact lens |
| US5880809A (en) * | 1996-12-30 | 1999-03-09 | Scientific Optics, Inc. | Contact lens |
Also Published As
| Publication number | Publication date |
|---|---|
| AU2001286004A1 (en) | 2002-03-04 |
| FR2813399A1 (en) | 2002-03-01 |
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