Abstract
An eye lens having a front lens element and a rear lens element, which each have a positive optical power and an optical region, and an intermediate element, which is connected to the lens elements outside the optical regions so that the lens elements and the intermediate element form a cavity. The eye lens allows the width of an access incision necessary for implantation to be reduced. The eye lens includes the lens elements and the intermediate element that are shaped such that, in the implanted state, a distance between the front lens element and the rear lens element is fixed and the cavity has an opening which allows liquid to flow into the cavity. Embodiments of the invention include a method for producing such an eye lens and a method for implantation.
Claims
1.-11. (canceled)
12. An eye lens that is implantatable in an eye, comprising: a front lens element having a first optical region and a first positive refractive power; a back lens element having a second optical region and a second positive refractive power; and an intermediate element, wherein the intermediate element is connected to the front lens element outside of the first optical region and wherein the intermediate element is connected to the back lens element outside of the second optical region, so that the front lens element, the back lens element, and the intermediate element together form a cavity, wherein the intermediate element fixedly spaces the front lens element from the back lens element when the eye lens is implanted, and wherein an opening extends into the cavity to allow liquid to flow into the cavity.
13. The eye lens as claimed in claim 12, wherein the front lens element and the back lens element are configured to allow the eye lens to be folded.
14. The eye lens as claimed in claim 12, wherein a thickness of the eye lens is less than 3 mm.
15. The eye lens as claimed in claim 12, wherein a thickness of the eye lens is less than 1.5 mm.
16. The eye lens as claimed in claim 12, wherein aa thickness of the eye lens is less than 0.9 mm.
17. The eye lens as claimed in claim 12, wherein a surface which is part of at least one of the front lens element or the back lens element and faces the cavity comprises a coating which mitigates the front lens element and the back lens element sticking together.
18. The eye lens as claimed in claim 12, wherein a surface which is part of at least one of the front lens element or the back lens element and faces the cavity comprises at least one of a stop or a diffractive optical structure.
19. The eye lens as claimed in claim 12, wherein at least one of the front lens element or the back lens element has exactly two optically effective surfaces.
20. The eye lens as claimed in claim 12, wherein at least one of the front lens element or the back lens element has an optically effective surface, wherein the optically effective surface is toric in shape.
21. The eye lens as claimed in claim 12, wherein at least one of the front lens element or the back lens element has an optically effective surface facing the cavity, wherein the optically effective surface is toric in shape.
22. The eye lens as claimed in claim 12, wherein the eye lens is formed in one piece.
23. The eye lens as claimed in claim 12, wherein the cavity contains a clear hydrophilic gel following an implantation of the eye lens into an eye.
24. A method for producing an eye lens as claimed in claim 12, comprising shaping the cavity with the opening using a process selected from a group consisting of: selective laser etching, ablating a lens material, punching, shaping by ion implantation, casting, bracing, and any combination thereof.
25. A method for implanting an eye lens as claimed in claim 23, comprising: inserting the eye lens into the eye; and introducing the clear hydrophilic gel into the cavity.
26. The eye lens as claimed in claim 12, wherein the front lens element, the back lens element and the intermediate element have a stiffness such that the eye lens is minimally deformed by forces typically encountered by the eye lens when the eye lens is in situ following implantation in the eye.
27. The eye lens as claimed in claim 26, wherein the front lens element, the back lens element and the intermediate element have the stiffness such that when the eye lens is in situ following implantation in the eye a distance between the front lens element and the back lens element changes by an amount selected from a group consisting of less than 20%, less than 10% and less than 5%.
28. The eye lens as claimed in claim 12, wherein each of the first positive refractive power and the second positive refractive power are fixed.
29. The eye lens as claimed in claim 12, wherein the eye lens is structured to be non-accommodating
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The invention is explained in greater detail below for example with reference to the accompanying drawings, which also disclose features essential to the invention. In the drawing:
[0035] FIG. 1a depicts a perspective illustration of a first example embodiment of an eye lens according to the invention;
[0036] FIG. 1b is a perspective illustration of a further example embodiment of an eye lens;
[0037] FIG. 2 is schematic illustrations of a third example embodiment of an eye lens in a top view and in two side views;
[0038] FIGS. 3a and 3b are schematic illustrations of the third example embodiment in two different sectional planes;
[0039] FIGS. 4a, 4b and 4c are schematic illustrations of the focal length for an eye lens according to the prior art and for a fourth and a fifth example embodiment
[0040] FIG. 5 are schematic illustrations of a sixth example embodiment of an eye lens in a top view and in two side views;
[0041] FIGS. 6a, 6b and 6c are schematic illustrations for variants of the lens elements in a sectional plane and a top view of details of the lens elements;
[0042] FIGS. 7a and 7b are schematic illustrations of a seventh example embodiment with toric surfaces in two different sectional planes;
[0043] FIG. 8 are schematic illustrations of an eighth example embodiment with toric surfaces in a top view and in two side views; and
[0044] FIG. 9 is a schematic illustration of the lens elements for a variant of the eye lens with a gel in the cavity.
DETAILED DESCRIPTION
[0045] FIG. 1a is a perspective illustration of a first example embodiment of an eye lens 1 according to the invention, which is designed for implantation in the capsular bag. The eye lens comprises a front lens element 10 and a back lens element 20 which is hidden in this perspective illustration. An intermediate element 30 is connected to both lens elements 10, 20. A cavity located between the lens elements and an opening are not drawn in this illustration. The intermediate element 30 is connected to two opposing haptic elements 60; in this example, these are shaped as a so-called plate haptic. The eye lens 1 is held in the eye in the implanted state by operation of the haptic elements 60. The optically effective surfaces of the front lens element 10 (and the first optical zone, not shown) and back lens element 20 (and the second optical zone, not shown) are responsible for the optical imaging properties of the eye lens 1. An optical axis A is perpendicular to an imaginary plane that is located between the cornea-facing surface of the front lens element 10—in the implanted state—and the retina-facing surface of the back lens element 20.
[0046] FIG. 1b shows a perspective illustration of a further example embodiment of an eye lens 1. It differs from the embodiment in FIG. 1a in that the haptic elements 60 are shaped, as so-called C-loops.
[0047] FIG. 2 shows a schematic illustration of a third example embodiment of an eye lens 1 according to the invention in a top view (top right) and in two side views (left and bottom). The z-direction corresponds to a view onto the eye lens 1 along the optical axis. The x- and y-directions are perpendicular thereto and perpendicular to each other. It should be noted that the illustrations here and in the other figures are not to scale. The top view (top right) shows the eye lens 1 from the z-direction. The front lens element 10 emerges from the plane of the drawing, while the back lens element 20 lies behind the plane of the drawing. The boundary of the back lens element 20 is therefore drawn as a dashed line; the radius of the back lens element 20 is smaller than that of the front lens element 10, whose boundary is represented by a solid line. The intermediate element 30 has an even larger radius; the outer edge is marked with a thin solid line. The inner edge of the intermediate element 30 is below the front lens element 10 and is marked as a dotted line. The (approximately) circular portion forms the boundary of the cavity 40 in the xy-direction. The shape of the intermediate element 30 ensures that it is connected to the lens elements 10, 20 outside the optical regions (not shown) of the said lens elements. The opening 50 is marked in the xy-plane by two dotted lines which extend to the outer edge of the lens elements 10, 20 and intermediate element 30. If the eye lens 1 is compressed for an implantation, liquid can flow into the cavity 40 through the opening 50 in the (negative) y-direction after the implantation. In the x-direction, the intermediate element 30 is connected on both sides to a respective haptic element 60 which is shaped as a plate haptic in this example embodiment.
[0048] The side view of the eye lens 1 shown on the left side of FIG. 2 corresponds to a view in the x-direction. Since the cavity 40 and the opening 50 are also located within the eye lens 1 in this view, they are represented by dotted lines. The two surfaces of the lens elements 10, 20 facing the cavity 40 are designed as flat surfaces.
[0049] A side view of the eye lens 1 from a y-direction is shown in the lower part of FIG. 2. In this view, the opening 50 is above the plane of the drawing; the opening 50 is therefore represented by a solid line.
[0050] To clarify the geometric relationships in the center of the eye lens, FIGS. 3a and 3b show, in two different sectional planes, schematic illustrations of the third example embodiment shown in FIG. 2. Here, FIG. 3a shows a section of the eye lens 1 in the yz-plane for an x-coordinate, which is marked S.sub.y in FIG. 2. Here, the opening 50 has an extent (thickness) in the z-direction which corresponds to the extent of the cavity 40 in the z-direction. This is the distance between the front lens element 10 and the back lens element 20.
[0051] FIG. 3b shows a section of the eye lens 1 in the xz-plane for a y-coordinate, which is marked S.sub.x in FIG. 2. The representations for the two sectional planes clarify the volume of the cavity 40. This volume of the eye lens 1 can be compressed for an implantation, and so the eye lens 1 can be introduced via an access incision with a particularly small width.
[0052] FIGS. 4a, 4b and 4c depict how the volume of the eye lens 1 according to the invention is reduced in comparison with an eye lens according to the prior art. To this end, FIG. 4a shows a schematic representation of the focal length of an eye lens 99 according to the prior art in a sectional image in the yz-plane for comparison purposes. A light beam 80 incident in parallel strikes a front side (facing the cornea) of the eye lens 99, is refracted there, passes through the eye lens 99, and exits again at a back side (facing the retina). Due to the curvatures of the front side and back side, the light is focused at a focal point 85. The focal point has a focal length. The z-positions of the vertices of the eye lens 99 and of the focal point 85 are marked using dotted lines.
[0053] Analogously, FIG. 4b shows the course of an incident parallel light beam 80 for an eye lens 1 according to the invention according to a fourth example embodiment. The cornea-facing surface 12 of the front lens element 10 and the retina-facing surface 22 of the back lens element 20 have the same curvatures as the eye lens 99 according to the prior art from FIG. 4a. The surfaces 14, 24 of the lens elements 10, 20 facing the cavity 40 are plane-parallel. The lens elements 10, 20 have the same refractive index as the eye lens 99 according to the prior art. For the purposes of representing the path the light takes, it was assumed that the cavity 40 is filled with aqueous humor, which has a lower refractive index than the lens elements 10, 20. The cavity 40 acts like a plane-parallel plate with a lower refractive index with respect to the lens elements 10, 20. This results in a focal length for eye lens 1 that is shorter than for the eye lens 99 according to the prior art without the cavity 40: The focal point 85 of light incident on the front lens element 10 in parallel is located closer to the vertex of the retina-facing surface 22 of the back lens element 20 than in the eye lens 99 without cavity 40. It follows that the eye lens 1 according to the fourth example embodiment shown here can achieve a higher refractive power than an eye lens 99 according to the prior art with the same external dimensions (such as the vertex distance between the front side and back side or between the corresponding surfaces 12, 22 of the eye lens 1).
[0054] This effect can be used to reduce the dimensions of the eye lens 1 in order to generate the same refractive power as exhibited by an eye lens 99 without cavity 40. This is depicted schematically in FIG. 4c. The curvatures of the cornea-facing and retina-facing surfaces 12, 22 of the lens elements 10, 20 are smaller. This results in smaller dimensions of the eye lens 1 according to a fifth example embodiment, shown here, compared to an eye lens 99 without cavity 40 but with the same focal length.
[0055] It should be noted that, in the fifth example embodiment, not only the curvature of the surfaces 12, 22, but additionally also the z-extent of the cavity 40 could have been adjusted in order to be able to generate the same focal length. Furthermore, it should be noted that, in the two example embodiments four and five, the extent of the opening 50 in the z-direction is less than the extent of the cavity 40 in the z-direction; however, this is irrelevant for the considerations relating to the refractive power and the reduction of the volume of the eye lens 1.
[0056] FIG. 5 shows schematic illustrations of a sixth example embodiment of an eye lens 1. The representations in the top view (top right) and the side views (left and bottom) correspond to those in FIG. 2. In the example embodiment shown here, the cavity 40 has two openings 50, 50′. The openings 50, 50′ are on opposite sides of the cavity 40. In this example, the openings 50, 50′ allow liquid to flow into the cavity 40 in the positive x-direction for opening 50′ and in the negative x-direction for opening 50. The two side views show that the cavity 40 and the openings 50, 50′ have the same z-extension. If an eye lens 1 shaped in this way is folded along the axis F, which is drawn in as a line of dots and dashes, the result is a particularly small volume of the eye lens 1 for an implantation.
[0057] It should be noted that, in the sixth example embodiment shown here, the intermediate element 30 comprises the haptics. This configuration of the intermediate element 30 is possible independently of the number of openings 50, 50′; the intermediate element 30 can also be shaped in this way in the other example embodiments shown. Furthermore, it should be noted that the embodiment shown here is particularly suitable for shaping the cavity 40 and the openings 50, 50′ by application of an ablating process, by stamping or by casting the eye lens 1.
[0058] In all the example embodiments of the eye lens 1 shown so far, the two surfaces 14, 24 facing the cavity 40 have a planar shape. Variants for these surfaces 14, 24 are shown in FIGS. 6a to c. For this purpose, the front 10 and the back 20 lens element are shown schematically on the left in a section in the xz-plane. On the right-hand side, a detail of the configurations is shown in each case in a top view in an xy-plane. All variants shown here can find use on the front 10 and/or back 20 lens element in the various example embodiments.
[0059] FIG. 6a shows a back lens element 20 on the left, which has a curvature on the cavity-facing surface 24. The back lens element 20 is shaped here as a meniscus eye lens; it has a positive refractive power. FIG. 6a furthermore shows a front lens element 10 which comprises a further lens 70. In this case, the further lens 70 has a refractive index which differs from the rest of the front lens element 10 (or from the first optical region). The front lens element 10 is thus designed like a kit element and has a positive refractive power. Chromatic aberrations, for example, can be corrected particularly well in this way. The further lens 70 is shown in top view on the right-hand side. Here, the thin, concentric lines represent contour lines.
[0060] On the left, FIG. 6b depicts a front lens element 10 which comprises a stop 72. The stop 72 is designed to be annular, as depicted on the right in the figure. Light is blocked in the region of the stop 72. In the example shown, the perceived depth of field can be adjusted in this way. In this example, stop 72 is located on a curved cavity-facing surface 14; this surface could also be designed to be planar. The back lens element 20 is shaped here as a biconvex lens.
[0061] On the left, FIG. 6c shows a diffractive optical structure 74 on both surfaces 14, 24 facing the cavity 40. The diffractive optical structure 74 is designed to be rotationally symmetric, as depicted on the right in the figure. Here, the rims of the diffractive optical structure 74 are shown as rings in top view. The diffractive optical structure 74 of the two lens elements 10, 20 is in each case superimposed on a curved surface 14, 24; said diffractive optical structures could also be superimposed on a flat surface. In this case, the structures are placed onto the surface 14 or they are “missing” from the surface 24. In an example embodiment, only one of the front 10 and back 20 lens elements has a diffractive optical structure 74. The structures 74 shown allow more than one refractive power to be provided.
[0062] FIGS. 7a and b show schematic illustrations of a seventh example embodiment in two different sectional planes. In this case, the sectional planes correspond to those from FIGS. 3a and b. In this example embodiment, the surface 14 of the front lens element 10 facing the cavity 40 has a spherical-toric shape. In the yz-plane shown in FIG. 7a, the surface 14 has a spherical shape with a curvature that deviates from the curvature in the xz-plane depicted in FIG. 7b. An aspherical-toric shape is likewise possible. The surface 24 of the back lens element 20 facing the cavity 40 has a cylindrical shape: In the xz-plane shown in FIG. 7b, the surface 24 has a spherical shape with a finite curvature while the curvature in the yz-plane depicted in FIG. 7a has an infinite radius of curvature.
[0063] It is also possible for only one of the surfaces 14, 24 facing the cavity to have a toric shape. Each of the two configurations of the lens elements 10, 20 shown may also occur in any of the other example embodiments discussed.
[0064] FIG. 8 shows schematic illustrations of an eighth example embodiment. In this case, the surfaces 14, 24 of the lens elements 10, 20 facing the cavil 40 have a cylindrical shape: The aforementioned surfaces 14, 24 have no curvature in a y-plane representation, while they have curvature in an xz-plane representation. An eye lens 1 shaped in this way is suitable for correcting astigmatism. In the depicted example embodiment, the cavity 40 has two openings 50, 50′. However—deviating from the sixth example embodiment depicted in FIG. 5—these are not oriented in the direction of the haptics, but are aligned perpendicularly thereto. In this way, the stability of the haptic is not affected. If an eye lens 1 shaped in this way is folded along the axis F, which is drawn in as a line of dots and dashes, the result is a particularly small volume of the eye lens 1 for an implantation. The embodiment shown here is particularly suitable for shaping the cavity 40 and the openings 50, 50′ using an ablating method such as drilling, or for stamping or casting the eye lens 1.
[0065] FIG. 9 shows a schematic illustration of the lens elements 10, 20 for a variant of the eye lens 1 with a clear, hydrophilic gel 90 in the cavity 40. This gel 90 can be introduced into the cavity 40 following an implantation of the eye lens 1. In this case, the gel 90 is chosen so that it additionally stabilizes the eye lens 1 in the hydrated state. Here, the gel 90 has a higher refractive index than that of aqueous humor. As a result, the total refractive power of the eye lens 1 is increased compared to an eye lens of the same geometry without gel 90. The gel 90 could also have a refractive index greater than that of the material of the lens elements 10, 20. In that case the total refractive power would be even greater.
[0066] In this case, the aforementioned features of the invention, which are described in various example embodiments, can be used not only in the specified example combinations but also in other combinations or on their own, without departing from the scope of the present invention.
[0067] A description of a piece of equipment relating to method features is analogously applicable to the corresponding method with respect to these features, while method features correspondingly represent functional features of the equipment described.
