FR2728458A1 - Intra-ocular correcting lens - Google Patents

Abstract

The correcting lens has a circular crenallure situated outside the optical portion of the lens and resting against the natural lens' posterior capsule. The crenallure comprises a soft edge with projections and notches or holes which may or may not be spaced regularly. In addition to the crenallure (22), the lens has a circular haptic section (21) for implanting in the capsule sac and a narrow gap to facilitate introduction.

Description

 The present invention relates to a corrective lens intended to be placed inside the eye to replace the optical power of the lens and to oppose the secondary clouding of the posterior capsule of this lens.

 During the cataract operation, an intraocular lens (Ll.O.), also called an intraocular or artificial lens implant, is put in place. It is introduced into rQil through an incision which was used first to remove most of the cataract lens. This incision can be very small, thanks to the special apparatus used. The anterior capsule of this lens is open in a linear circular manner allowing the removal of a central washer having a diameter generally ranging from 4 to 7 mm; after which the entire interior of the lens - nucleus and cortex - is removed, so that only the capsular bag remains, formed behind by the posterior capsule and in front by the remaining peripheral part of the anterior capsule, both capsules joining next to what is called the equator of the lens. It is in this capsular bag, of circular shape with a diameter of about 10 mm, that the corrective lens of the desired power will be placed.

 Most lenses in use today have two parts, a central unit called optics, a device called haptics, usually forming a whole made in one piece. The haptic is generally flexible, compressible, the optic being rigid. But we are seeing an increase in the number of lenses with foldable optics. One of the goals pursued by ophthalmologists is indeed to obtain implants that can pass through the smallest possible opening.

 Another goal is to manage to keep the posterior capsule transparent throughout the years that follow the establishment of an L.l.O. Posterior capsular clouding remains the major drawback of this method called extra-capsular extraction which has supplanted the total extraction of the lens, called intracapsular. This clouding presents itself schematically under two aspects: a - fibrosis, the cause of which remains imprecise, probably favored by the contact between the convex posterior surface of the optic and the posterior capsule; b - the "pearls", made up of cellular clusters, much more frequent. They are due to the migration of cells coming from the equator of the lens: in this region, at the periphery of the capsular bag, it is indeed not possible to remove all the cells, which will eventually proliferate, migrate to the center of the posterior capsule and cloud it. This requires the secondary opening of this capsule. However, this opening, whatever the means used, can lead to various complications which would be avoided if the posterior capsule could therefore be kept transparent. There are solutions to oppose these cellular migrations: chemical or pharmacological, physical, biological, mechanical. But it is obviously essential that they are safe for the eye (chemical processes in particular), and none has to date imposed.

 The device according to the invention makes it possible to hope to eliminate these clouding by pearls, or at the very least to greatly slow down the occurrence thereof. It falls under the last category of the solutions listed above, mechanical solutions. It consists in establishing a peripheral barrier on which the cells coming from the periphery will come to butter. Dams of this kind have already been proposed, for example in the form of a circular ring added to the haptic. However, all of the existing systems are part of the usual concern in terms of LIO, which consists in making curvilinear structures, the smoothest, most regular possible. However, such structures are the least capable of opposing the passage of cells that will line the posterior capsule. On the contrary, it is necessary to carry out irregular dams, thus comprising a much larger developed surface which will therefore form a more effective obstacle, and which can cause localized peripheral fibrosis, which is also effective. The essential condition to be observed is that these dams keep edges sufficiently foamed so as not to risk perforating the posterior capsule.

 The dam in question has the appearance of a notch, with notches, protrusions and incisures - or even indentations at the closed limit constituting as many orifices - forming a succession of bumps and hollows, according to methods which can be varied, as well as for the shape of the slots, as for their dimensions, their depth, or their exact seat in relation to the optics or the peripheral haptics.

The appended drawings illustrate by way of nonlimiting example several embodiments of the device according to the present invention. On these:
- Figure 1 is an anterior view of an eye, with the outline of a limbic incision of 5 mm at noon.

 - Figure 2 is a sagittal vertical section of the anterior part of the eye very schematically showing the situation of a lens of the type shown in Figure 3, in place in the capsular bag. All details are not reproduced. Reference is made to the anatomy textbooks for the description of an eyeball. The numbers 1 and 2 relate respectively to the cornea and to the sciene. The number 3 designates the anterior eye chamber, the 4 Lirais, the 5 the pupil, the 6 the corneal irido angle, the 7 the posterior chamber, the 8 the ciliary body, the 9 the capsular bag, the 10 its anterior opening , the 11 the fibers of the zonule, the 12 the limbus where the conjunctiva which covers the anterior part of the siderea is inserted and is not represented here.

 - Figure 3 is a schematic anterior view of a dassic implant with two handles and rigid optics, bordered by a circular notch made of regularly spaced slots.

 FIG. 4 is an anterior view of a circular implant with rigid optics bordered by a circular notch of the same principle but of a different shape than that of FIG. 3.

 - Figures 5 and 6 are anterior views of circular implant with rigid optics, of the same family as that of Figure 4; but in FIG. 5 the notch is not very protruding and is located on an intermediate ring separated from the edge of the optic by a free space.

 - Figure 7 shows a double ring composed of two circular handles, intended to occupy the bottom of the capsular bag and comprising a notch at the outer edge of the inner handle.

 - Figure 8 shows another model of double ring, also with a notch, but different, and a fixing system with two holes.

 - Figure 9 shows an assembly consisting of the double ring of Figure 7 on which has been placed a foldable optical lens.

 - Figure 10 shows the foldable lens of the previous diagram 8, this time shown in isolation and no longer in place on the ring.

 - Figure 11 shows another model of foldable lens with locking rotation system for attachment to the peripheral double carrier ring.

 The device, object of the invention, will now be described in its three main variants corresponding to the three main categories of L.l.O. that we can schematically distinguish.

 A first category is made up of lenses with two diametrically opposite handles. It is by far the most used model. The notch (14) will be placed at the periphery of the optics (15), in continuity with it and will be circular, framing the foot of the two handles. There should be a sufficient degree of angulation (16) of the two haptics 17), facilitating better contact and even if possible a real support of the crenellated area against the posterior capsule (18). The introduction of the lens into the anterior chamber then in the capsular bag is done in a dassic way. (Such lenses, as soon as they have a sufficient diameter, can also be put in place no longer in the capsular bag but in ciliary support). One of the incisions of the circular notch can be a little deeper (19) on such a meridian, the diametral opposite projections being less marked (20); so that the lens can be introduced into the eye by rotation through a slightly smaller incision.

 A second category is represented by so-called circular lenses, comprising a circular haptic (21). In this case, the crenellated annular border (22) can be placed adjacent to the optics, at its periphery, as for the two-lens dassic lenses of the first category previously considered. Or this notch can be separated from the optic by a free interval, and be in the form of a ring (23) concentric with the optic, placed in an intermediate position between the edge of the optic (24) inside. , and the circular peripheral part of the haptic (25) outside. In this case the optic is connected to the crenellated ring by one or more bridges (26), for example two almost diametrically opposite as in Figure 5. The crenellated ring is itself connected to the outer ring of Ibaptique: here , in Figure 5, on either side of the opening (27) facilitating the passage of the lens in the capsular bag. In the case where they are contiguous to the optics, the crenellations can also present themselves with the variant (already described with regard to lenses with two handles constituting the first category of LlO) of a longer incision on such meridian facing opposite projections, on the contrary, less marked. The outer part of the haptic is in all cases angled with respect to the notch. Generally, these lenses are introduced into the anterior chamber of the eye by playing on the compressibility of the haptic, then in the capsular bag thanks to this same compressibility and with the help of the narrow opening made in the outer part of the haptic.

A third category is represented by initially independent lenses which will be fixed on a double carrier ring previously introduced into the capsular bag. This is a category which is not yet developed. It has already been proposed to introduce into the capsular bag simple rings to maintain the circular shape of the bag, in particular in the event of partial disinsertion of the zonule (which connects the lens bag to the wall of the ocular gbbe); and we associated with it the installation of a dassic lens with two handles. This is a completely different kind of ring. It actually consists of a double ring (28), with therefore two circular elements,
One external, the other internal - which will be called in the following descriptions external circular handle (29) or internal (30) - concentric, connected by several bridges (31), thus giving the assembly a structure coherent, semi-rigid while remaining partially compressible. Each of the two circular handles can be of simple cylindrical section but also of rather flattened shape while having a generally convex curvature towards dobby. A narrow opening, made perpendicularly or better obliquely (32), facilitates, better than simple compressibility would do, the introduction of the ring into the anterior chamber of the eye then into the capsular bag, the maneuver being able to '' perform in two steps or at the same time.In this latter case, the optimal shape of the opening is oblique, with a bevel (33) formed on the inner part of the inner circular handle so that it is first engaged in the capsular bag, at the same time where the double ring finishes being introduced by rotation into the anterior chamber through the small incision. The width of this double ring can vary, in practice especially between 1.5 and 2.5 mm, since the capsular bag has a diameter of about 10 mm and it is important to leave a sufficiently large central surface, a diameter from 5 to 6 mm appearing the most recommendable. Such a double ring, 2 mm wide, can easily be introduced into the eye through a 3 mm incision. This double ring is smooth on its external part. It can also be smooth on its internal part, the internal circular handle being able to alone to make an anti-cellular barrier, but this barrier will therefore be even better if this internal circular loop is crenellated over 360 "as has been described for the two main categories of IOL previously considered. In this case, the crenelation (34) will best be practiced so that the bevelled end of the internal ranse facing the narrow opening has a slight rounded bulge (35) which will participate in the ensernbb of the notch and will favor, by slightly protruding inside, introduction of the ring by its internal circular handle in the capsular bag. The bridges connecting the two external and internal circular handles of the double ring have an angulation, as on the lenses of the first era and second pre-planned categories. This angulation, around 10 to 15, and which may be less or on the contrary greater, allows better occupancy of the capsular bag at the periphery, with moderate tensioning of the posterior capsule better applied to the crenellated internal ranse of the double ring thus placed in position a little more later. This angulation also has the advantage of opening the space (36) between the outer edge of the inner circular shackle and the inner edge of the outer circular shackle. In this space will come to sintercaier the peripheral part, designed for this effect, of the lens subsequently introduced into the anterior eye chamber.

 This lens can be flexible and foldable. It can thus also pass through a simple opening of 3 mm, while having for example an optical diameter of 6 mm. These flexible foldable lenses hitherto used have the disadvantage of being less well maintained in the capsular bag than rigid dassic lenses with two handles or circulars of categories 1 and 2.

Their haptic is in fact itself flexible and can move secondarily, undergoing the retractions likely to occur inside the capsular bag. As a result, these lenses may become off center. Nor can they oppose cellular migrations.

The advantage of this device is thus to associate a stable, coherent peripheral element and thundering anti-cellular barrier, with a flexible foldable lens introduced by a minimal opening and which is going to be fixed on the double peripheral carrier ring.

The shape of the lens is established according to the method of attachment to the double carrier ring. In the model shown here, it has a circular optic (37) 6 mm in diameter and a haptic having at each of its ends a median slot (38) which will engage on either side of each of the two bridges (31) aligning in the same meridian but diametrically opposite and connecting the outer and inner circular handles of the double support ring. This will immediately eliminate the risk of lateral displacement. For greater security, the width of the haptic is such that it can just pass between two other bridges (39), this time external, which thus frame the haptic laterally. At each of its ends, the haptic is thinned, or notched (40), so that it can be gently pushed and wedged between the two circular handles of the double ring, in the open space thanks to the angulation previously described between external and internal handles. It should also be recalled that at this level the haptic will also be covered by the peripheral part of the anterior capsule,
The central opening of the anterior capsule (capsulorhexis) being necessarily limited and not exceeding 7 mm in diameter. To facilitate insertion maneuvers it is desirable that the capsulorhexis be sufficiently large (at least 6 mm). Once thus enclosed, the lens, the total length of which corresponds to the diameter of the bag (approximately 10 mm), will be very stable in the capsular bag and will not become off center under the influence of secondary retractions, because b double peripheral ring will maintain the circular shape of the bag. What is more, it will help to maintain the inner circular handle and its crenellations well placed on the posterior capsule whose center awa thus more likely to remain transparent. Finally, the assembly thus produced is easily reversible, we can either in progress intervention, or by re-intervening, easily remove the lens to replace it with another of better suited optical power.

 The protocols which have just been described have been for explanatory purposes, other ways of proceeding being usable according to the variants of the device, and this without departing from the scope of the invention. The notches can in particular vary in their shape, their regular arrangement or not, their number, their depth. They can be joined to the optics or be separated by a free interval. These variants are found according to the three main categories of L.l.O.

previously described. The first major category, the most common, is also the most stereotypical. In the second, that of circular lenses, there are many potential models of haptics. And the same is true for the third category, that of foldable lenses with a double peripheral support ring. Other variants may in this last category concern the double ring, in particular the width of its two handles, the width of the space which separates them, their degree of angulation; but also the diameter and the shape (circular, oval, square, rectangular, polygonal) of the optic whose rear face, moreover, can be convex, plane, concave. (Same variations possible for the optics of the first 2 main categories of L.l.O.). Variants can also and especially relate to the form of the haptic.

conditioning the conditions for its attachment to the double support ring: hooking with rotation blocking (41); notching in the thickness; suturing with fixation holes (42; etc.

The haptic may also include one or more rotational holes to facilitate handling of the lens.

 The execution of these L.l.O. must strive for the greatest possible perfection on the technical level, and in particular in the choice of materials, whether those already used such as polymethyl methyl methacrylate (P.M.M.A.) or being the result of future inventions. Within the framework of the third major category of L.l.O., the material used for the manufacture of the double ring is preferably also P.M.M.A., tested for decades; but it may also be other products such as glass, various polymers, preferably transparent, etc. The material used for the foldable lenses is in particular hema, or else silicone, or any other material deemed suitable. These materials must be well tolerated by the eye and machinable, so as to obtain lenses of defined power in a wide range of diopters; with progression of the order of half a diopter, to meet all needs; with possible so-called progressive correction associated for near vision; with a protective element for better biocompatibility; etc. The whole set is made according to maximum quality, as part of a miniaturization corresponding to what microsurgery of the eye is.

 In summary, the present invention provides progress in the field of optical correction and maintenance of posterior capsular transparency during the operation of cataracts.

It has been described and represented by way of indication but in no way limitative, and is susceptible of various variants or modifications, of which only a few have been envisaged, without going beyond its scope.

Claims (10)

 1 - Corrective intraocular lens, intended to replace the optical power of the lens, and to oppose the secondary opacificabon of the posterior capsule of this lens, characterized in that it comprises a circular notch (14, 22, 23,34) located outside the optics and pressing against the posterior lens capsule.  2 - intrasuscular lens according to claim 1, characterized in that the circular notch is made up of elements with sufficiently foamed edges, with notches, projections and incisures or even indentations at the closed limit constituting as many holes -, regularly or not spaced , forming a succession of bumps and depressions of reduced or much more marked depth, according to various geometric modes such as any crenelation may have.  3 - Intraocular lens according to claims 1 and 2, characterized in that, being integrated into the category of conventional lenses, comprising a central optic (15) and a peripheral haptic in the form of two diametrically opposite handles (17), implantable both in the capsular bag and in the ciliary support, it has a notch (14) directly united to the optic which it extends at the periphery, the crenellated elements developed on 360 bordering on both sides the starting point or foot of the two handles.  4 - Intraocular lens according to claims 1 and 2, characterized in that, being integrated into the category of lenses comprising a central optic and a circular haptic (21), implantable in the capsular bag alone, it has a notch ( 22) directly joined to the optic which it extends at the periphery, one of the incisions may be a little deeper on such a meridian, and the diametrically opposite projections then being less marked. 5 - Intraocular lens according to claims 1 and 2, characterized in that, being integrated in the same category as the lenses concerned in the preceding claim, that is to say comprising a central optic and a circular haptic, it has a notch which will no longer be united at the periphery of the optic, but separated from the edge of this optic by a free space, in the form of an intermediate ring (23) located between optic inside and external circular haptic outside, the optic being connected to this intermediate notch and beyond to the ring of the external haptic by connecting bridges (26), being associated with the fact that the internal crenellated ring and the external ring also have a narrow opening (27), sot perpendicular, sot oblique, facilitating the introduction of the lens into the capsular bag. 6 - Intraocular lens according to claims 1 and 2, characterized in that, being integrated into the category of lenses made up of several elements, it will comprise two parts introduced successively into the eye and composed, on the one hand '' a double carrier ring (28) with two circular handles (29 - 30) external and internal, intended to occupy the periphery of the capsular bag, the notch being located on the internal circular loop, on the other hand of a flexible lens , foldable, comprising a central optic (37) and a haptic which is fixed on the double peripheral ring, said crenelation therefore remaining marked on 360 - but can also, at most, be very reduced or even limited to a flattened or cylindrical handle. 7 - Intraocular lens according to claims 1, 2 and 6, characterized in that the double carrier ring, of a width of the order of 1.5 to 2.5 mm, without being completely rigid, has a certain consistency with stabilizing and anti-deforming role, by the existence of bridges (31) connecting the two handles, two of these bridges aligning in the same meridian but being diametrically opposite, said double carrier ring being interrupted only by a narrow opening, perpendicular or better oblique (32), facilitating the introduction into the capsular bag, the internal circular notch (34) interrupted at this point then being reinforced by a rounded bulge (35) and a little more salient again favoring the passage in the capsular bag. 8 - intrasuscular lens according to claims 1, 2, 6 and 7, characterized in that the foldable lens coming to be fixed on the double carrier ring has a peripheral haptic comprising two median slots (38) diametrically opposite each coming to fall apart and the other of each of the two bridges (31) also diametrically opposed on the double support ring, other bridges (39) laterally framing the edges of the haptic, the end of which is by thinned or notched aileus (40), to be better wedged between the two circular handles of the double support ring. 9 - Intraocular lens according to claims 6, 7 and 8, characterized in that the system for attaching the lens to the double carrier ring is effected by isolation, but also by rotation blocking (41), pressure, suture with orifices fixing (42), the shape of Phaptic being adapted according to each of these fixing methods.  10 - Intraocular lens according to any one of the preceding claims, characterized in that the circular notch is on a plane a little more posterior than the most peripheral part of the haptic, thanks to an angulation (16) placing this part device further forward and favoring the support of the crenelation on the posterior capsule (18), The space located between crenelation and outer handle - in the category of lenses with double carrier ring and foldable lens - allowing passage then isolation of the peripheral part of the foldable lens.