Accommodating intraocular lenses

Abstract

Accommodating intraocular lenses containing a flowable media and their methods of accommodation.

Claims

1. An accommodating intraocular lens, comprising: an optic that includes a deformable anterior element that includes an anterior most location of the optic, the deformable anterior element adapted to deform to change the power of the accommodating intraocular lens, a posterior element that includes a posterior most location of the optic, and an optic fluid chamber; a first haptic that is secured to the optic and that extends radially outward from the optic, the first haptic having an anterior portion that extends further in the anterior direction than the anterior most location of the optic; and a second haptic that is secured to the optic and that extends radially outward from the optic, the second haptic having a posterior portion that extends further in the posterior direction than the posterior most location of the optic, the first and second haptic each comprising a material and a configuration such that they are adapted to deform in response to capsular bag reshaping.

2. The accommodating intraocular lens of claim 1, wherein the first and second haptics each have a fluid chamber in fluid communication with the optic fluid chamber.

3. The accommodating intraocular lens of claim 1, wherein the first haptic also extends further in the posterior direction than the posterior most location of the optic.

4. The accommodating intraocular lens of claim 1, wherein the second haptic also extends further in the anterior direction than the anterior most location of the optic.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

(2) FIGS. 1, 2A, and 2B illustrate the structure and operation of a human eye.

(3) FIGS. 3-5 show an exemplary embodiment of an intraocular lens.

(4) FIG. 6 shows a portion of an exemplary intraocular lens in disaccommodative and accommodative configurations.

(5) FIG. 7 shows an exemplary optic portion of an intraocular lens.

(6) FIGS. 8A-8C show an alternative embodiment of an intraocular lens.

(7) FIGS. 9-12 show an alternative embodiment of an intraocular lens.

(8) FIGS. 13-15 show an alternative embodiment of an intraocular lens in varying accommodative configurations.

(9) FIG. 16 shows an exemplary haptic being compressed between a lens capsule and an optic portion.

(10) FIGS. 17-20 show exemplary alternative haptic designs.

(11) FIG. 21 illustrates dimensions of an exemplary haptic.

(12) FIG. 22 shows an exemplary haptic design and a capsule in accommodated and disaccommodated configurations.

(13) FIGS. 23 and 24 show an alternative haptic design comprising bellows.

DETAILED DESCRIPTION

(14) The invention relates generally to intraocular lenses (IOLs) and particularly to accommodating intraocular lenses. In preferred embodiments the IOL includes a flowable media (such as a fluid, gelatinous material, etc.) that is moved within the IOL, in response to ciliary muscle movement, to change the power of the IOL.

(15) FIGS. 1 and 2 illustrate the structure and operation of a human eye. Eye 100 includes cornea 1, iris 2, ciliary muscles 3, ligament fibers or zonules 4, capsule 5, lens 6 and retina 7. Natural lens 6 is composed of viscous, gelatinous transparent fibers, arranged in an onion-like layered structure, and is disposed in transparent elastic capsule 5. Capsule 5 is joined by zonules 4 around its circumference to ciliary muscles 3, which are in turn attached to the inner surface of eye 0. Vitreous 8 is a highly viscous, transparent fluid that fills the center of eye 100.

(16) Isolated from the eye, the relaxed capsule and lens take on a convex shape. However, when suspended within the eye by zonules 4, capsule 5 moves between a moderately convex shape (when the ciliary muscles are relaxed) and a highly convex shape (when the ciliary muscles are contracted). As shown in FIG. 2A, when ciliary muscles 3 relax, capsule 5 and lens 6 are pulled about the circumference, thereby flattening the lens. As shown in FIG. 2B, when ciliary muscles 3 contract, capsule 5 and lens 6 relax and become thicker. This allows the lens and capsule to assume a more convex shape, thus increasing the diopter power of the lens.

(17) Additionally, various natural mechanisms affect the design requirements of the present invention. For example, during accommodation the pupil naturally stops down (i.e., reduces in diameter) which reduces the area of the natural lens that transmits light. In addition, the eye will experience the Stiles-Crawford Effect which also reduces the effective area of the natural lens. In particular, the brightness of light rays incident on cones in the eye is dependent on the angle at which those rays are incident on the cones. In particular, light rays that strike the cones perpendicular to their surface appear brighter than those that do not. As a result, the light rays passing through the periphery of the lens are less significant for proper vision.

(18) FIGS. 3-5 show a first embodiment of accommodating IOL 10. IOL 10 includes a peripheral non-optic portion comprising haptics 12 and 14. The IOL also includes an optic portion including anterior lens element 16, intermediate layer 18 which comprises actuator 20, and substrate, or posterior element, 22. Anterior element 16 is bonded to intermediate layer 18 at its periphery. In some embodiments the anterior element may also be bonded to actuator 20. The intermediate layer is also bonded to posterior element 22. The inner surface of haptics 12 and 14 define interior volumes 24 which are in fluid communication with active channel 26 defined by posterior element 22 and intermediate layer 18. As shown, actuator 20 is integral with intermediate layer 18. Posterior element 22 is molded with buttresses 11 which include a buttress bore 13 therethrough. The haptics have a haptic attachment element 15 (which can be stiff or flexible) which is sized and shaped to fit within buttress bore 13. An adhesive layer can be applied to the outer surfaces of the haptic attachment elements and/or the inner surface of the buttress bore to facilitate attachment of the haptics to the optic portion. The IOL contains a flowable media within the haptics and the active channel. The IOL also includes passive chamber 21 that is defined by the anterior element and the intermediate layer. The passive chamber contains a second flowable media (e.g., a fluid, elastomer, etc.), which may be the same as the fluid within the haptics and active channel, or it may be a different flowable media. The active channel and the passive chamber are not in fluid communication.

(19) Deformation of haptics 12 and 14 in response to contraction of ciliary muscles movement transfers the flowable media (such as a fluid) between interior volume 24 and active channel 26. When the flowable media is transferred into the active channel from the haptics, the pressure in the active channel increases, causing actuator 20 to deflect in the anterior direction. This causes anterior element 16 to deflect in the anterior direction, increasing the IOL power in this accommodated configuration.

(20) In any of the embodiments herein, moving fluid between the haptics and the optic portion can cause the change in curvature of the posterior element rather than, or in addition to, the anterior element. While changing the curvature of the anterior element is described herein, this is not meant to be limiting to the IOLs. For example, the IOL can be flipped upon implantation such that the anterior element is disposed on the posterior side of the lens, while the posterior element is disposed on the anterior side of the lens. Moving fluid from the haptics to the optics would therefore cause the posterior surface of the IOL deflect. Alternatively, the actuator can be in contact with the posterior element and the active channel can be defined by the intermediate layer and the anterior element, while the passive chamber is defined by the posterior element and the intermediate layer. Moving fluid from the haptics to the active channel would thereby deflect the posterior element.

(21) FIG. 6 is a cross sectional view of a section of an exemplary IOL showing the IOL in a disaccommodated state (dashed lines) and an accommodated state (solid lines). The IOL includes anterior element 74, intermediate layer 78 which includes actuator 73, and posterior element 75. Actuator 73 is comprised of deflection element 71 and bellows 70. When the pressure is increased in active channel 72, bellows 70 change configuration from the generally conical shape of the disaccommodated state to a curvilinear configuration of the accommodated state. Deflection element 71 is forced in the anterior direction due to the increase in pressure. This causes anterior element 74 to deflect in the anterior direction as well, steepening the curvature of the anterior element and thereby increasing the power of the lens.

(22) All of the components of the optic portion, including the active flowable media and the passive flowable media, can be substantially index-matched to provide for a generally singular lens element defined by the anterior surface of the anterior element and the posterior surface of the posterior element. Substantially index-matched as used herein refers to an IOL whose components are intended to have the same index of refraction, but whose actual indices may differ slightly. The term also refers to a lens which can have adhesive (to bond different components of the lens together) which may have an index of refraction that is slightly different than the indices of the other IOL components.

(23) Some of the components may, however, have different indices of refraction, creating additional interfaces within the IOL.

(24) FIG. 7 is a cross sectional view of an IOL (haptics not shown) similar to that shown in FIGS. 3-5. FIG. 7 illustrates exemplary dimensions of the optic portion of the IOL. Anterior element diameter 30 is about 6.0 mm. The anterior element thickness 31 at the center of the anterior element is about 0.43 mm. Intermediate layer edge thickness 32 is about 0.35 mm. Intermediate layer center thickness 33 (i.e., deflection element center thickness) is about 0.63 mm. Bellows length 40 is about 1.0 mm. Bellows thickness 34 is about 0.10 mm. Actuator diameter 35 is about 3.40 mm. Posterior element edge thickness 36 is about 0.60 mm. Posterior element center thickness 37 is about 0.70 mm. Posterior element diameter 38 can be about 6.6 mm to about 7.4 mm. The IOL center thickness 39 (in the disaccommodated configuration) between the anterior surface of the anterior element and posterior surface of the posterior element along the optical axis of the lens is about 1.8 mm to about 2.2 mm.

(25) Bellows thickness 34 can be adjusted to change the responsiveness of the actuator. As the thickness of the bellows decreases, less fluid pressure is generally required to displace the actuator. In some embodiments the bellows thickness is between about 0.05 mm and about 0.3 mm.

(26) Decreasing the anterior element thickness 31 generally increases the responsiveness of the actuator for a given fluid pressure. Length of bellows 40 can also be adjusted to alter the responsiveness of the actuator (actuator diameter 35 can similarly be adjusted). As the length of the bellows increases, the volume of the active channel is increased and more volume of flowable media is required to move the actuator. However, by increasing the bellows length, the pressure in the active channel is decreased. Therefore, the volume and pressure required to drive the actuator can be optimized in combination with the flowable media transferred from the haptics to provide the greatest response.

(27) In some embodiments the length of the bellows is between about 1 mm and 2 mm. In some embodiments actuator diameter 35 is between about 2.8 mm and about 4.2 mm.

(28) The dimensions given above are merely exemplary and not intended to be limiting.

(29) FIGS. 8A-8C show an additional embodiment of IOL 401. IOL 401 includes anterior element 404, intermediate layer 402, posterior element 400, and haptics 412. Intermediate layer 402 comprises an actuator, which comprises deflection element 406 and bellows 408. Also shown are passive chamber 405 and active channel 410. As can be seen in FIGS. 8B and 8C, anterior element 404 and intermediate layer 402 are bonded directly to posterior element 400, which removes an intermediate assembly step of coupling the intermediate layer 402 to the anterior element 404 (as is the construction in the embodiment shown in FIGS. 3-5). Anterior element 404 and intermediate layer 402 are both bonded to posterior element 400 along their periphery. Anterior element 404 is bonded to posterior element 400 at a location more radially outward from the optical axis OA than is intermediate layer 402.

(30) The amount of shape change (i.e., the change in curvature) that the anterior element will undergo in response to fluid movement between the peripheral portion and the optic portion will depend partially on how and where the anterior element is bonded to either the intermediate layer or the posterior element. By varying these boundary conditions it is possible to change the optic power shift for a given amount of displacement at the center of the lens. For example, an anterior element bonded at the very edge of its periphery will deflect in a more spherical manner than will an anterior element that is bonded more radially inward than merely at its periphery. The former is allowed to flex all the way out to its periphery, while the latter is more constrained when deflected and will assume a less spherical configuration when in an accommodated configuration (i.e., will have a stronger aberration).

(31) In addition, the lens bonded at its periphery will deflect at lower active channel pressures than will a lens that is bonded closer to the center.

(32) The anterior element is attached to the posterior element at surface 417 of the posterior element. This mating surface is substantially orthogonal to the optical axis OA. This helps with the assembly process, and gives anterior element 404 a firm foundation on which to sit. FIG. 8C shows a cross sectional perspective view including haptics 412.

(33) The posterior element in FIG. 8A includes buttresses 411. Buttresses 411 include nipples 413 which are adapted to fit within haptic bore 415 to attach the haptics to the posterior element. Adhesive can be applied to the mating surfaces.

(34) FIGS. 9-12 show an alternative embodiment of IOL 200. IOL 200 includes anterior element 202, intermediate layer 204, posterior element 206, and haptics 208. The haptics are attached to the intermediate layer 204 by attaching buttress elements 212 with optic buttresses 210. The actuator includes deflection element 213 and bellows 215. FIG. 12 is a top view showing the haptics (optic portion not shown). As can be seen, haptic buttress element 212 is incorporated into haptic 208 and attaches to the optic portion at optic buttress 210. One difference in this embodiment is that most of the mechanical complexity is incorporated into one component of the lensthe intermediate layer. Because the haptics incorporate a buttress element, the change in direction (roughly 90 degrees) of the flowable media occurs in the haptic buttress element rather than in an optic buttress as is the case in the embodiments shown in FIGS. 3-5 and FIGS. 8A-8C.

(35) FIGS. 13-15 illustrate an alternative embodiment in which deflection element 312 of the intermediate layer is not in contact with anterior element 302 during the entire accommodation motion of the lens. FIG. 13 shows IOL 300 in a disaccommodated state including anterior element 302, intermediate layer 304 (including deflection element 312 of the actuator), and posterior element 306. The IOL includes gap 310 between the deflection element and the anterior element. When there is no pressure in active channel 308 or in passive chamber 314 (as shown in FIG. 13), the geometry and passive fluid state is such that there is gap 310 between the deflection element and the anterior element.

(36) As the pressure in active channel 308 increases (due to movement of the capsular bag), deflection element 312 moves in the anterior direction. Because of the pressure transfer into passive chamber 314, anterior element 302 also moves in the anterior direction (thus increasing the power of the lens) but remains generally spherical. The deflection element deflects more quickly than the anterior element, until they engage, as shown in FIG. 14.

(37) As the pressure in the active channel continues to increase, the actuator continues to deflect in the anterior direction. Because the deflection element is in contact with the anterior element, further deflection element movement deflects the anterior element. Because of the size of the deflection element relative to the anterior element, the fluid in passive chamber 314 redistributes and creates an aspheric effect in anterior element 302, as shown in FIG. 15. This further increases the power of the IOL for a smaller aperture.

(38) This embodiment allows for a lower power change rate at relatively low stimulus levels (FIG. 14) and a higher power change rate at higher stimulus levels (FIG. 15). The anterior element can remain generally spherical when under a low stimulus and becomes aspherical when under a higher stimulus.

(39) One or more of the optic components can be made from suitable polymeric materials. In one embodiment all of the optic components are made of substantially the same polymeric material. Exemplary polymeric compositions that can be used for the optic portion include those described in commonly owned, co-pending U.S. patent application Ser. No. 12/034,942, filed Feb. 21, 2008, and U.S. patent application Ser. No. 12/177,720, filed Jul. 22, 2008.

(40) The haptics are disposed on the lens such that when implanted in the lens capsule, the haptics deform in response to the capsule shape changes. The capsule changes shape as the zonules apply or relax forces on the capsule in response to ciliary muscle relaxation or contraction.

(41) In one embodiment the IOL is a fluid-driven accommodating IOL which is adapted to move fluid between an interior chamber in the haptics and the optic portion in response to ciliary muscle movement to cause a change in the power of the lens. In a particular embodiment the fluid is moved to the optic portion as the ciliary muscles begin to contract, causing the zonules to relax the forces applied to the capsule. As the zonules relax the forces, the capsule and/or the optic portion compress the haptic, resulting in fluid moving to the optic portion and an increase in fluid pressure in the optic portion. The fluid movement causes a deflection in an anterior element of the lens, which increases the power of the lens.

(42) FIG. 16 shows the cross sections of an exemplary haptic 50 being compressed between the lens capsule 52 and the optic portion 54 by compressive force B. Because the fluid is moved between the haptic and optic portion as the haptic is compressed, the responsiveness of the haptic to the change in forces from the capsule is important in creating an energy efficient IOL. It is generally desirable to transfer energy as efficiently as possible from the forces applied or relaxed on the capsule to the anterior element displacement. The overall shape of the haptic, and perhaps more importantly, the cross-sectional shape of the haptic, can influence how efficiently fluid is transferred between the haptic and the optic portion in response to ciliary muscle relaxation/contraction. It is desirable to obtain a greater response from the haptic in response to a change in force on the lens capsule. It is also desirable to have a haptic/lens system that responds quickly to changes in capsule state.

(43) FIGS. 17-20 show exemplary haptic shapes and cross sections. FIG. 17 shows a haptic with an elliptical cross section, with a height H greater than width W. FIG. 18 shows a haptic with a D shaped cross section. FIG. 19 shows an alternative haptic shape with a circular cross section. FIG. 20 illustrates a haptic with a flat oval cross section.

(44) Other shapes and/or cross sections can also be used to provide for a more responsive haptic. In addition, the haptic may be comprised of a plurality of sections each with differing polymeric compositions, which may allow one section of the haptic to be stiffer than a different section, which could help increase the responsiveness of the haptic. Exemplary polymeric compositions that can be used for the haptics include those described in U.S. patent application Ser. No. 12/034,942, filed Feb. 21, 2008, and U.S. patent application Ser. No. 12/177,720, filed Jul. 22, 2008.

(45) Wall thicknesses can also be varied in a given cross-section to allow localized movement and to increase efficiency. FIG. 21 is a cross sectional view showing the exemplary cross section of a haptic. Haptic height 260 is between about 3.0 mm and about 3.4 mm. Haptic width 262 is between about 1.2 mm and about 2.0 mm. Haptic wall thickness 264 is between about 0.1 mm and about 0.3 mm. These dimensions are merely exemplary and are not intended to be limiting.

(46) In some embodiments the haptic shape may be adapted to more naturally mate with the curved equatorial portion of the lens capsule in an disaccommodated state, or to better compliment the corresponding mating surface of the lens. This may help increase the responsiveness of the haptic and decrease the amount of lost movement due to dead space between the haptic and the capsule. FIG. 19 is an example of this. FIG. 22 shows an additional cross sectional design of haptic 300, in addition to the capsule in accommodated and disaccommodated configurations.

(47) FIG. 23 shows an alternative haptic design comprising bellows 501 along one side of haptic 500. The haptic can be attached to the optic portion using any of the methods described or referenced herein. Haptic 500 can also include a reinforcing element 502 along the peripheral side of the haptic to ensure the haptic contacts the capsule bag equator. The reinforcing element can be, for example, a reinforced nitinol wire (metal) or monofilament (plastic).

(48) FIG. 24 is a top view showing IOL 512 in a disaccommodated state (natural relaxed state) before implantation relative to exemplary capsular bag 506. Haptics 500 have a diameter of about 10 mm. The optic portion has a diameter of about 6 mm. When implanted in the capsular bag, the capsular bag relaxation causes pressure to be exerted on the haptics, thus bending the haptics. The bellows provide for greater volume reduction in the haptics, which displaces more volume of fluid to the optic portion.

(49) Additional exemplary accommodating IOLs that can incorporate any of the features described herein are described in commonly owned U.S. Provisional Application No. 60/433,046, filed Dec. 12, 2002; U.S. Pat. Nos. 7,122,053; 7,261,737; 7,247,168; and 7,217,288; U.S. patent application Ser. No. 11/642,388, filed Dec. 19, 2006; and U.S. patent application Ser. No. 11/646,913, filed Dec. 27, 2006, the disclosures of which are hereby incorporated by reference in their entirety.

(50) While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.