FR2899093A1 - Refractive intraocular lens for use during e.g. myopia, has opaque part, and haptic part with haptic elements, where haptic part is arranged such that posterior surface remains in contact with anterior surface of iris - Google Patents

Abstract

The lens has an opaque part (10) and a haptic part (20). The part (20) has haptic elements (21) adapted to be supported in an irido corneal angle. The haptic part is arranged, such that a posterior surface remains in contact with an anterior surface of an iris. The part (20) has a transversal articulation (28) on both sides of the part (10), where the articulation is transversal with respect to a longitudinal axis of the part (20).

Description

The present invention relates to the field of implants or lenses

  intraocular (IOL), and more particularly refractive intraocular lenses of the anterior chamber, especially for phakic eye, that is to say one that has its natural lens.

  The refractive problems or ametropia of the eye concern first myopia, hyperopia and astigmatism. These visual defects can be corrected by the wearing of glasses or contact lenses, the laser photo-ablation of the corneal stroma, also called LASIK (ie laser in situ keratomileusis), photo-refractive keratectomy (PKR), the implantation of refractive intraocular lenses or intracorneal rings. Presbyopia affects almost the entire population from the age of 45. It results from the loss of accommodation of the natural lens caused by the aging of certain ocular tissues, and in particular the ciliary body. It is treated by the same means as refractive problems. However, the use of glasses or intraocular lenses is the treatment of choice. There are, however, intraocular lenses to correct refractive problems such as myopia, hyperopia and / or astigmatism as well as presbyopia. There are several categories of refractive intraocular lenses for phakic eye (see JL Alio "Advances in Phakic Intraocular Lenses: Indication, Efficacy, Safety and New Design", Ophthalmology 2004, 15: 305-357) where are cited intraocular fixation implants. iris, pre-crystalline intraocular implants and anterior chamber implants with fixation or support in the iridocorneal angle. The implantation of iris-fixing intraocular lenses proves to be delicate and involves relatively large corneal incisions, with the well-known postoperative disadvantages in particular. Pre-crystalline implants are still quite controversial, especially for fear of the risk of premature cataracts induced by contact between the pre-crystalline implant and the lens. We can distinguish two generations of phakic eye implants of anterior chamber fixation or support in the iridocorneal angle. The implants of the first generation were made mainly of rigid material, such as PMMA. The first phakic eye implant of anterior chamber and therefore of this first generation was that of Dr. Baikoff, US Patent No. 5,071,432, sold under the name ZB. Among the implants of this first generation, is also known the phakic eye implant of anterior chamber supported in the iridocorneal angle, marketed under the trademark Nuvita and made entirely of PMMA. Like all intraocular lenses, these include an optic and two or more loop-shaped haptic elements that come into contact with the iridocorneal angle. Such implants have the major disadvantage, namely an excessive support force of the haptics in the iridocorneal angle, which can cause intraocular hypertonia and even open-angle glaucoma.

  The present invention is more particularly concerned with the second generation of phakic eye implants for anterior chamber, that is to say anterior chamber intraocular lenses made mainly or exclusively of flexible material. The advantage of anterior chamber intraocular lenses of this type is that they can be folded or wound to pass through small corneal incisions, and avoid generating too much bearing force in the iridocorneal angle. The haptics are angulated previously, so that the optics and more particularly the anterior pole thereof are advanced towards the posterior surface of the cornea, and in particular the endothelial cells. There is therefore a risk of contact and loss of central endothelial cell density of the cornea. A phachic anterior chamber intraocular lens of this type is described in the PCT patent application filed on April 1, 2003 and published under the number WO 2003/089958. In addition, the haptic portion comprises a ramp extending on either side of the optical portion at the end of which is an arcuate beam whose outer edge is concave. At each end of the beam is a support zone or foot intended (e) to come into contact in the iridocorneal angle. By the arcuate configuration of this beam, overpressures can develop at one or more of the support zones, due in particular to the annular contour of the iridocorneal angle which is rarely a perfect circle but more or less oval and may have other contour irregularities. Similarly, the choice of the diameter of the implant is difficult given the uncertainty of the surgeons as to the actual diameter of the iridocorneal angle usually determined by simple approximation from values of white to white ("white-to-white "). A second example of intraocular lens of anterior phakic eye chamber marketed under the ICARE brand by the company Corneal and presented at the ESCRS Congress from 6 to 10 September 2003 (Ophthalmological Reflexions of October 2003). This one-piece lens is made from a hydrophilic acrylic polymer (25% water content). The haptic portion has four independent wide base feet or support zones, each of which is connected to a radially outwardly extending bridge associated with a hinge with a bearing surface of 0.50 mm. extending over a segment of the circle to the overall diameter of the implant and intended to reduce the pressure of the bearing points on the iridocorneal angle. The haptic portion is angulated substantially in the continuity of the curvature of the optic portion to create an anterior arch so that the pole of the anterior surface of the optics advances to the cornea with the risk of contact with the endothelial cells. The configuration of the anterior surface of the iris varies between a substantially flat surface to more or less convex or curved forms towards the front. Variation of the anterior surface configuration of the iris has never been considered in phakic eye anterior chamber implants as it may affect the positioning and stability of the implant in the eye. iridocorneal angle. The object of the invention is to provide an intraocular lens of anterior chamber for phakic eye which avoids, or in any case reduces, disadvantages of the intraocular lenses of the state of the art.

  According to the present invention, there is provided an intraocular lens made mainly or entirely of flexible material and comprising a body having an optical part and a haptic part, the haptic part comprising a plurality of haptic elements shaped to be kept in contact with the angle. iridocorneal. Its haptic part is shaped so that its posterior surface can remain in contact with the anterior face of the iris. Unlike the usual practice of the state of the art where the haptic part is kept away from the iris and more particularly from the anterior surface thereof, the intraocular lens according to the invention allows the contact between the haptic part. and the anterior surface of the iris. Among the advantages of the intraocular lens according to the invention and the fact that by keeping in contact with the anterior surface of the iris, the optical part remains relatively far from the cornea. Another advantage of the intraocular lens according to the invention is that the haptic part can adapt to the shape of the anterior surface of the iris which varies between substantially flat shapes and more or less convex or curved towards the anterior. The force applied by the iris against the implant is very small but sufficient for the haptic portion to adapt to the shape of the anterior surface of the iris. This results in no discomfort during dilatation or contraction of the iris, nor during accommodation of the lens, the iris being simply very slightly tightened between the crystalloid and the intraocular implant. According to another aspect of the invention, the haptic portion comprises on either side of the optical portion a transverse articulation relative to the longitudinal axis of the haptic portion. As a result, the haptic portion beyond the transverse joint can be adapted to the shape of the anterior surface of the corresponding iris. According to a preferred characteristic, each of the transverse joints is constituted by a zone of reduced mechanical strength and for example of reduced section, as defined by a groove opening anteriorly. Alternatively, the area of reduced strength has a plurality of transversely aligned openings in the haptic portion. Preferably, each of the haptic elements has feet articulated around an axis parallel to that of the optical part. Each of these feet is articulated independently of the others. According to one embodiment of the invention, the haptic elements have a curved contact edge whose contact area is greater than 1 mm. According to one embodiment, the haptic portion has an anterior angulation less than 15, preferably less than 7, or even between about 0 to 2.

  According to one embodiment, the feet have a shaped curved contact edge to obtain substantially the same extent of contact between this edge and the iridocorneal angle, regardless of the angular position of the haptic element. The features and advantages of the invention will emerge from the description of embodiments given by way of example, with reference to the appended drawings, in which: FIG. 1 is a front perspective view and a side view of an anterior chamber intraocular lens for a phakic eye according to an embodiment of the present invention; FIG. 2 is a front view of the intraocular lens of FIG. 1, the four feet of the haptic part in the rest state being substantially tangent to a circle; FIG. 3 is a front view similar to that of FIG. 2 for one of an intraocular lens according to a second embodiment; FIG. 4 is a front view of the intraocular lens of FIGS. 1 and 2 to illustrate different positions of the haptic feet as a function of the diameter of the iridocorneal angle; FIG. 5 is a sectional view on the axis of symmetry of the intraocular lens of FIG. 1, the concave-convex optical portion having a negative vergence; FIG. 6 is a sectional view on the axis of symmetry of the intraocular lens of FIG. 1, the concave-convex optical portion having a positive vergence; FIG. 7 is a sectional view corresponding to that of FIG. 6, in which the intraocular lens is implanted in the anterior chamber of the eye whose anterior surface of the iris is substantially flat; and FIG. 8 is a sectional view corresponding to that of FIG. 6, in which the intraocular lens is implanted in the anterior chamber of the eye whose anterior surface of the iris is more or less convex or convex. The intraocular lens of the anterior chamber for the described phakic eye comprises, like any intraocular lens, an optical portion 10, a haptic portion 20 which comprises at least two haptic elements 21 and as illustrated, two haptic elements. In this case, the axis of symmetry of the intraocular lens passes through the optical portion 10 and the haptic elements 21. The intraocular lens is preferably made entirely or mainly of flexible material and in particular of hydrophilic flexible material, such as polymer or copolymer acrylic. Alternatively, the intraocular lens is made of hydrophobic flexible material, such as silicone. Although the embodiment in one piece is preferred, the present intraocular lens can be made of several assembled components, and in particular the optical part and the haptic part in a manner known per se. Likewise, the present lens may comprise parts made of rigid material, while allowing it to be folded or wound up so that it can be introduced into a small corneal or sclerocorneal incision, that is to say from the order of 3 mm. The rigid material parts can be obtained by selective modification, in accordance with the teachings of the European patent application EP1.003.446.

  The optical portion 10 is preferably concave-convex, the anterior face 12, 12A being convex and the rear face 11, 11A concave, so as to avoid inadvertent contact between the posterior face of the optics and the crystalline lens (CR). through the pupil in the center of the iris (IR), see Figures 7 and 8. This optical configuration allows the realization of negative vergence optics (see Figure 5) from -6 to -24 diopters for example, for correction myopia and optically positive optics between, for example, +3 and +9 diopters for the correction of hyperopia. For the entire family of negative vergence, the concave posterior face 11, 11A has the same invariable radius of curvature, namely of the order of 4 to 5 mm. Likewise, the diameter of the optical portion for negative vergence up to about 14 diopters and positive vergences is preferably about 6 mm while for negative vergences greater than about -18 diopters, the diameter of the optical portion is preferably lower, for example 5.5 mm. The optical portion 10 may be monofocal or multifocal with a central zone of far vision and at least one annular zone for near vision (not shown). For example, the optical portion may comprise a central portion having a vergence between -10 and +10 diopter a peripheral annular portion having an addition between +2 and +5 diopter, as described in EP 1.200.020. Similarly, the optical portion 10 can be corrected to reduce spherical or other aberrations, including positive corneal (CO) and negative (CR). The optical part 10 comprises the actual optics surrounded by an annular zone 13 and of variable width as a function of the correction which extends all around and which does not have any optical function. The haptic portion 20 comprises two haptic elements of flat type with at least one, and in practice two feet 30 likely to form bearing areas with the iridocorneal angle. These haptic elements 21 extend radially between the annular zone 13 and the feet located near their free edge. Each flat type haptic element comprises an intermediate plate 22 whose transverse width is sufficiently wide and thick to ensure good stability of the lens once implanted, thus preventing twisting. As illustrated, the quadrilateral intermediate plate 22 has a generally trapezoidal shape, whose large concave base adjoins the annular zone 13 of the optical portion 10 and the small base radially remote from the optical portion is also concave as illustrated. . The lateral edges 25 of the intermediate plate 22 converge away from the optics. It goes without saying that the general shape of the intermediate plate 22 may be different, for example the lateral edges 25 may be more or less parallel and the right outer edge 27, or slightly concave 26. According to the illustrated embodiment, each foot 30 is articulated to the intermediate plate 22. Preferably, the hinge zone 33 is defined by a bridge or hinge of reduced thickness but other forms of articulation can be adopted. The feet 30 have an extended rest position where their support zone is on a circle corresponding to the overall diameter of the intraocular lens. As a function of the diameter of the iridocorneal angle or more exactly of the position of each portion of the iridocorneal angle with respect to its geometric center, the foot 30 is more or less folded against the elastic force of the bridge or the hinge 33 urging the foot to its deployed position.

  Figure 4 shows an intraocular lens whose four feet each have a different position, for illustrative purposes. It is therefore noted that the foot at the top right is substantially in its deployed position and tangential to the circle of the largest diameter. The bottom right foot adopts an intermediate position tangent to the circle of the second smaller diameter. The foot at the bottom left is less folded than the previous one and tangent to the circle of the second largest diameter. Finally, the upper left foot is folded close to the limits determined by the adjacent lateral edge of the plate of the haptic element and is tangent to the circle of the smaller diameter. It is understood that the maximum retracted position can be determined by the contact between the foot and the transverse edge of the corresponding intermediate plate. Since each foot has its own independent articulation, the position of each foot adjusts independently of the others, so that the angular position of each foot around its hinge 33 depends solely on the distance of the portion of the irido angle. - Corneal of its geometric center. This gives a positioning perfectly adapted to each iridocorneal angle and excellent stability of the implanted lens and radial distribution of the bearing forces. Each foot has an outer curved contact edge 32 and an inner edge 31, for example rectilinear. It is this inner edge that is close to the lateral edge of the corresponding plate as a function of the folding of the foot. The curved contact edge 32 is shaped to obtain substantially the same extent of contact between it and the iridocorneal angle, regardless of the angular position of the foot. This curved contact edge therefore has the general shape of a cam. The anterior face of each foot is oblique so that the thickness of each foot decreases from an edge 31A substantially parallel to the inner edge 31 to the curved contact edge 31 whose thickness is about 0.10 mm. Each of the haptic elements is angulated slightly earlier. The angulation towards the anterior is less than 15 and preferably less than 7 and in practice between 0 and 2.

  According to the present invention, the haptic portion may be adapted to the anterior surface configuration of the iris which may vary between a substantially planar surface and a more or less convex or curved surface. To this end, each haptic element has a hinge extending in a direction transverse to the longitudinal axis or to the axis of symmetry of the intraocular lens. In practice, this joint is disposed closer to the optical portion than the feet and extends in a direction substantially perpendicular to the longitudinal axis of the intraocular implant. Each transverse joint 28 is defined by a zone of reduced mechanical strength and in the present embodiment an area of reduced thickness. As illustrated, this area of reduced thickness is a groove 29 extending from one side edge to the other of the intermediate plate 22. The section of this groove 29 can be U-shaped flat bottom, U-shaped to rounded bottom as shown or V. Any section of the groove 29, it opens before. In the embodiment of FIGS. 1, 2 and 4 to 8, the groove 29 is rectilinear and opens on both sides of the lateral edges 25. The inner edge of the groove 29 is substantially tangential to the zone annular. In the variant illustrated in FIG. 3, the transverse articulation 28A comprises a zone of reduced thickness 29A which extends between the outer periphery of the annular zone 13 and the arcuate flange extending transversely between the lateral edges 25 and dividing thus in two the plate 22 in an inner portion of reduced thickness and in an outer portion of greater thickness.

  Whether the transverse articulation 29 is illustrated in FIG. 1 or that 29A illustrated in FIG. 3, the fold or plication line will extend substantially perpendicular to the longitudinal axis of symmetry of the implant and substantially in the middle of the transverse joint concerned.

  Alternatively, the area of reduced thickness is replaced by a softer area than the rest of the intermediate plate 22 to define the joint. This variant can be made in accordance with the technology described in EP1.003.446. In any case, thanks to this zone of reduced mechanical resistance, the inclination of the plate located beyond the articulation can vary with respect to the general plane of the optical part. The present intraocular anterior chamber implant for phakic eye can accommodate different configurations of the anterior surface of the iris between a substantially planar configuration in a plane perpendicular to the optical axis of the implant to more or less convex configurations or curved previously. The force applied by the iris against the implant is very small but sufficient for the haptic portion to adapt to the shape of the anterior surface of the iris. This results in no discomfort during dilatation or contraction of the iris, nor during accommodation of the lens (CR) where the iris (IR) will be very slightly tight between the crystalloid and the intraocular implant. As an implant made mainly or entirely of flexible material, it can be folded or wound so as to allow introduction by a small incision, for example 3 mm. Preferably, the present lens will be wound or folded about an axis perpendicular to the longitudinal axis of the implant. Its configuration also makes it possible to use an injector of the known type, and in particular that described in the French patent application published under No. 2,833,154 and marketed under the trademark RTU by the company loltech. Once introduced into the anterior chamber, the intraocular lens is positioned so that the feet 30 abut in the iridocorneal angle, each of the legs 30 adopting a folded position corresponding to the distance between the contact portion of the iridocorneal angle and its geometric center. Because of the zone of reduced mechanical resistance, the portion of the haptic plate can tilt so as to adapt to the anterior surface of the iris, whether flat or more or less convex or curved. The pole of the anterior face 12, 12A of the optical part 10 remains well spaced from the endothelial cells of the cornea (CO) without, however, any risk of contact between the concave posterior surface 11 of the optic part and the lens ( CR). According to a non-illustrated embodiment, each of the haptic elements comprises feet, each foot having an outer rim adapted to be in contact with the iridocorneal angle and thin strands attached to the ends of the rim, a window being defined. by the rim and the strands, the strands being deformable to fit the contour of the iridocorneal angle. According to a non-illustrated embodiment, each of the haptic elements comprises feet associated in pairs, a strand attached to each of the feet of a pair ensures the rest position of the pair of feet and a joint for each of the feet around an axis parallel to the axis of the optical part.

  It goes without saying that the present invention is not limited to the described embodiments nor to the preferred materials, but on the contrary covers all variants of structures and configurations and materials compatible with the objects of the present invention.

Claims (17)

  1. Anterior chamber refractive intraocular lens for phakic eye, of the type made mainly of flexible material and comprising a body having an optical portion (10) and a haptic portion (20), the haptic portion comprising a plurality of haptic elements (21). ) adapted to be supported in the iridocorneal angle, characterized in that the haptic portion is shaped so that its posterior surface remains in contact with the anterior face of the iris.   2. refractive intraocular lens according to claim 1, characterized in that the haptic portion (20) comprises on either side of the optical portion (10) a transverse articulation relative to the longitudinal axis of the haptic portion.   3. refractive intraocular lens according to claim 1, characterized in that the haptic portion (20) comprises on either side of the optical portion (10) a transverse articulation relative to the longitudinal axis of the haptic part so that that the haptic portion (20) is adapted to adapt to the contours of the anterior surface of the iris depending on its shape.   4. The refractive intraocular lens according to claim 2 or 3, characterized in that each of the transverse joints (28; 28A) is constituted by a zone of reduced mechanical resistance.   5. Refractive intraocular lens according to claim 2 or 3, characterized in that each articulation (28; 28A) comprises a groove (29; 29A) opening anteriorly.   Refractive intraocular lens according to claim 4, characterized in that the zone of reduced mechanical resistance comprises a plurality of transversely aligned apertures in the haptic portion.   7. Refractive intraocular lens according to claim 4, characterized in that the zone of reduced mechanical strength comprises a strip of softer material than that of the rest of the haptic part. 30   8. refractive intraocular lens according to any one of claims 1 to 7, characterized in that the haptic portion (20) comprises two haptic elements (21), each of these haptic elements having a hinge (28; 28A) extending substantially transversely to the longitudinal axis of the axis of the optical part.   9. Refractive intraocular lens according to any one of claims 1 to 8, characterized in that the haptic portion (20) has feet (30) adapted to be in contact in the iridocorneal angle, the feet having an axis. articulation extending substantially parallel to the axis of the optical portion (10).   10. Refractive intraocular lens according to claim 9, characterized in that the haptic portion (20) comprises two haptic elements (21), each having a pair of feet (30) with an angular deflection capacity of about 20 to 35.   11. Refractive intraocular lens according to claim 10, characterized in that the angular deflection capacity is about 30.   12. Refractive intraocular lens according to any one of claims 1 to 11, characterized in that the posterior face of the haptic portion (12) has a radius of curvature greater than that of the posterior face (11) of the optical part ( 10).   13. Refractive intraocular lens according to any one of claims 1 to 12, characterized in that the haptic portion (20) has an anterior angulation less than 15.   14. refractive intraocular lens according to any one of claims 1 to 12, characterized in that the haptic portion (20) has an anterior angulation less than 7.   15. Refractive intraocular lens according to any one of claims 1 to 12, characterized in that the haptic portion (20) has an anterior angulation of about 0 to 2.   16. Refractive intraocular lens according to any one of claims 9 to 15, characterized in that the feet (30) of the haptic elements (21) have a curved contact edge (32) shaped to obtain substantially the same extent of contact between this edge and the iridocorneal angle, whatever the angular position of the foot of the haptic element.   17. The refractive intraocular lens according to claim 16, characterized in that the haptic elements (21) have a curved contact edge (32) whose contact area is greater than 1 mm. comprises two haptic elements (21), each haptic element having a plate (22) of generally quadrilateral shape, feet (30) being articulated at the radially outer corners of the plate. 19. Refractive intraocular lens according to any one of claims 1 to 8, characterized in that the haptic parts comprise at least two haptic elements having feet, each foot having an outer rim adapted to be in contact with the iridoid angle. corneal and thin strands attached to the ends of the flange, a window being defined by the flange and the strands, the strands being deformable to fit the contour of the iridocorneal angle. 20. refractive intraocular lens according to any one of claims 1 to 8, characterized in that the haptic part comprises two haptic elements each having paired legs, a strand attached to each of the feet of a pair to ensure the position resting the pair of feet and an articulation for each of the feet about an axis parallel to the axis of the optical portion.