Accommodating Intraocular Lens

Abstract

An intraocular lens for insertion into a capsular bag of an eye comprises: an optic; and at least one plate haptic coupled to the optic by one or more flexible connecting members. The plate haptic with flexible finger extensions is designed to engage the periphery of the capsular bag. An increase in radial pressure upon constriction of the ciliary muscle causes the rigid posteriorly vaulted plate haptics to move centrally to further increase the vitreous cavity pressure with constriction of the ciliary muscle: the optic with its thin stretchable hinge across the connecting member is then displaced anteriorly along the axis of the eye. The haptic includes a longitudinally rigid frame to restrict deformation of the haptic in a longitudinal direction while permitting deformation in a transverse direction. Furthermore, the flexible connecting members include one or more hinged straps that extend radially and/or longitudinally from the optic. The optic can move forwards and backwards, relative to both the distal and proximal ends of the plate haptics, in response to ciliary muscle contraction and relaxation with an increase and decrease of vitreous cavity pressure. Finger-like projection extends from the plate haptic to engage the capsular bag to center and fixate the accommodating lens within the capsular bag.

Description

BACKGROUND OF THE INVENTION

Accommodating Intraocular Lenses were developed in the early 1900's and have been sold in Europe for the last ten years and later in the U.S. They function by means of forward movement of the optic upon constriction of the ciliary muscle which increases the pressure in the posterior part of the eye with a simultaneous decrease in pressure in the front part of the eye pressure. The reverse pressure changes take place upon relaxation of the ciliary muscle, which results in the backwards movement of the lens for distance vision. The forward movement of the lens optic enables the patient implanted with the lens to automatically change their vision from distance to see at intermediate and near.

The currently marketed accommodating plate haptic intraocular lenses provide excellent distance and intermediate vision but sometimes require weak, +1.00, reading glasses for prolonged reading, for seeing small print, or reading in dim lighting conditions. The embodiments relating to the present invention presented herein are designed to substantially reduce the need for any reading glasses

It is important for intraocular lenses to have a consistent location along the axis of the eye to provide good uncorrected distance vision and to center in the middle of the vertical meridian of the eye. Without excellent uncorrected distance vision there is no point in implanting an accommodating lens whose function is to enable patients to be without glasses. With the advent of the new premium lenses, not only are the above requirements important but also the vision is likely to be better if the lens after implantation and centration, is without any tilt which can reduce the quality of vision particularly if the lens optic has a toric component or is a multifocal.

The word “haptic” has been used to describe an attachment to intraocular lenses. The original intraocular lens consisted of a single optic. These single optic lenses, without any attachments, were first implanted in London by Harold Ridley in 1949. These lenses frequently de-centered and it was discovered that there was a need to center and fixate the lens optic in the vertical meridian of the eye.

The first attachments to the optic were called “haptics”. They consisted of multiple flexible loops of various designs, J loops, C loops, closed loops and flexible radial arms.

Later, these loops which became commonly referred to as “haptics” were replaced in some lens designs with plates, called “plate haptics”. It is necessary to fixate and center the plate haptics within the capsular bag and so loops or fingers are extended from the distal lateral ends of the plate haptics. These can be of the same material as the plate or integrally molded into the plate lens design during manufacturing, and can be made of polymide, prolene PMMA or titanium.

When the accommodating lens plate haptic is fibrosed into the capsular bag of an eye after cataract surgery, sometimes several weeks or months following the surgery, a complication can occur. The lens can deform to a “Z” dislocated shape. This occurs when there is little sandwiching of the distal tip of the plate haptics between the remaining anterior and the posterior walls of the capsular bag.

The current accommodating lenses utilize an oblong lens body design having plate haptics connected to the lens optics by a single transverse hinge across the plate haptic. This promotes accommodation by allowing the optic to move forwards and backwards relative to the outer, or distal, ends of the plates. Such accommodating lenses are found in U.S. Pat. No. 5,476,514 and U.S. Pat. No. 5,496,366, both to Cumming, the disclosures of which are herein incorporated by reference. However, these designs do not permit adequate movement of the optic to a change in vitreous cavity pressure to allow many patients to read comfortably at near without glasses.

In order to increase the movement of the optic to respond to the increase in vitreous cavity pressure that occurs during constriction of the ciliary muscle, the transverse hinge may be weakened by elongating the hinge base or reducing the width of the hinge. However, elongating the hinge base would destabilize the lens optic, and making the hinge narrower would make it prone to tilting.

BRIEF SUMMARY PREFERRED EMBODIMENTS

An accommodating intraocular lens design according to an embodiment of the present invention is described that overcomes the deficiencies of present designs noted above.

A flat, longitudinal accommodating intraocular lens is provided, having distinct separate plate haptics that are rigid longitudinally, but flexible transversely, and that extend to partially surround the optic. The flat plate haptics may have a groove or hinge across the width of its proximal ends adjacent to the optic. This hinge may be weakened by having at least two separate spaced apart narrow hinges on each edge of the plate haptics, thereby, reducing the overall width of the hinge. This plural strap design stabilizes the lens optic while reducing the resistance of the optic to a change in vitreous cavity pressure, thereby, allowing more movement of the optic along the axis of the eye. Further stabilization is achieved by making the haptics as wide, or wider, than the optic and extending the lateral proximal ends of the plate haptics to partially surround the optic. The plate haptics may be made rigid longitudinally by incorporating into the length of the haptics a rigid frame structure.

Thus, an accommodating lens according to the present invention may stabilize the solid, single, flexible lens optic, prevent tilt, provide more movement of the optic for better near vision and center and fixate the lens in the capsular bag with the finger-like flexible loops at the distal ends of the plates. This accommodating lens improves near vision by reducing the resistance to pressure changes on the optic with contraction and relaxation of the ciliary muscle and by further increasing the vitreous cavity pressure by means of the lateral plate haptic extensions, which with accommodation and constriction of the ciliary muscle are forced posteriorly such that their proximal ends to then lie posterior to the optic.

Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the presently described apparatus and method of its use.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Illustrated in the accompanying drawing(s) is at least one of the best mode embodiments of the present invention In such drawing(s):

FIG. 1 illustrates a top view of an accommodating intraocular lens according to an embodiment of the present invention;

FIG. 2 illustrates a top view of a haptic according to an embodiment of the present invention;

FIG. 3 illustrates a top view of exemplary frames according to an embodiment of the present invention; and

FIG. 4 illustrates a side view of a hinge according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The above described drawing figures illustrate the described invention and method of use in at least one of its preferred, best mode embodiment, which is further defined in detail in the following description. Those having ordinary skill in the art may be able to make alterations and modifications to what is described herein without departing from its spirit and scope. Therefore, it should be understood that what is illustrated is set forth only for the purposes of example and should not be taken as a limitation on the scope of the present apparatus and its method of use.

As illustrated in FIGS. 1 and 3, an intraocular accommodating lens 10 for insertion into an eye having a ciliary body, comprises: a lens optic 100 having a longitudinal axis and a normal axis perpendicular thereto, and one or more plate haptics 200 coupled to the optic via at least one connecting member 300, the connecting member operable to permit movement of the optic substantially along a first axis of the eye in response to force applied substantially along the longitudinal axis by contraction of the ciliary body.

The lens optic is preferably constructed of a flexible optical material such as silicone, hydrogel, acrylic material, but may be made of any similar material. Additionally, the lens optic is preferably shaped so as to be biconvex, refractive, diffractive, plano-convex, Fresnell, spheric, aspheric, toric or multifocal.

In a preferred embodiment, at least two plate haptics 200 are longitudinally coupled to opposing ends of the lens optic 100. As illustrated in FIGS. 1 and 3, each plate haptic 200 may comprise: a frame 250, a body 210, and at least one projection 260.

Turning now to FIG. 1, the body of the haptic comprises at least one lateral end 220 a proximal end 230, a distal end 240 and a plate 270. The haptic body is preferably substantially flexible in a transverse direction, but rigid longitudinally, and is preferably made of silicone, hydrogel, acrylic, or similar material. In one embodiment, the plate haptic body may be of substantially the same width as the lens optic. Thus, the lateral ends may extend substantially parallel to each other and substantially tangential to the lens optic. In another embodiment, the lateral and proximal ends of the plate haptics may comprise a proximal flange, or paddle, 222, as shown in FIG. 3, that partially surrounds the optic and makes the haptic at least as wide as the optic. In one embodiment, the haptic is wider than the optic. Such construction offers increased stabilization of the optic and the plate. Preferably, the width of the haptic is approximately between 3.0 and 7.0 mm. Ideally the width of the haptic is between 4.50 and 6.00 mm. Preferably the haptic thickness is between 0.20 to 0.75 mm. The optic diameter preferably varies from 4.5-7.0 mm, and in one embodiment is approximately 5.0 mm.

As shown in FIG. 1, the plate haptics may further comprise at least one substantially flexible projection 260 extending substantially from the distal end. The projection may comprise: an open loop, a closed loop, a tangential extension, a notch or indentation in the distal end 240, or a lateral extension of the distal end, or any combination of the preceding or other geometries known in the art. The flexible projections or fingers may be of the same material as the plate haptic and/or the lens optic, or may be polymide, prolene, polymethylmethanylate (PMMA), titanium or similar material. In one embodiment, the projection comprises a homogenous integral part of the plate haptic body. In another embodiment, the projection comprises a distinct unit set into the plate haptic during molding. Preferably, the projections measure from 2.0 to 4.0 mm in length extending from the distal end of the haptic body and are flexible extending to a transverse diameter that exceeds the diameter of the capsular bag.

As illustrated in FIG. 1, the plate haptic may further comprise a frame 250 operable to strengthen the plate haptic and substantially reduce the flexibility of the plate haptic in at least one direction. In one embodiment, the frame comprises a plurality of substantially rigid, longitudinally arrayed frame segments 252. Preferably, the frame is operable to reduce haptic flexibility along the longitudinal axis, while permitting flexibility along a transverse axis. The frame may be formed separately and embedded within the body, or may be unitarily formed therewith. In one embodiment, the frame comprises a thickened area of the haptic body. Additionally, the frame and projection may or may not be unitarily constructed. Furthermore, the frame may be of the same material as the plate haptic and/or the lens optic, such as silicone, acrylic, hydrogels, or other similar material.

The accommodating lens further comprises at least one connecting member 300, shown in FIGS. 1-4, connecting the plate haptic to the optic. The connecting members are preferably flexible and extend substantially between the plate haptic and the lens optic. The plate haptic is affixed at its proximal end to the connecting member, which is in turn affixed to the lens optic. In one embodiment, the connecting member preferably extends radially from a peripheral edge 110 of the lens optic and is affixed to the proximal end of the plate haptic, as shown in FIGS. 1 and 3. In another embodiment, the connecting member extends substantially longitudinally from the peripheral edge of the lens optic and is affixed to the proximal end of the plate haptic, as shown in FIG. 2.

As illustrated in FIG. 1, in one embodiment, the flexible connecting member preferably comprises at least one strap 310 and a hinge 320 configured to traverse the width of the strap, the strap being flexible about the hinge. In one embodiment, the hinge traverses the strap substantially tangential to the peripheral edge of the lens optic. In another embodiment, the hinge traverses the strap in a substantially lateral direction. Preferably, the hinge comprises a groove 320 traversing the strap, as shown in FIG. 4, but multiple grooves may be present without departing from the scope of the invention. As shown in FIG. 4C, in one embodiment, the hinge comprises an upper groove 322 and a lower groove 324 preferably situated on opposing sides of the strap. Preferably, the hinge thickness is approximately half the thickness of the strap, or may be, between 0.1 and 0.3 mm.

As illustrated in FIG. 1, in one embodiment, two or more straps couple each of two plate haptics to the optic thereby tending to substantially prevent tilting of the optic with respect to the haptics. In the above embodiment, the straps are preferably removed an equal distance from the longitudinal axis and form an aperture therebetween. In another embodiment, a single strap couples each plate haptic to the optic.

In another embodiment, the connecting member comprises the proximal end of the plate haptic body, the proximal end being substantially thinner than the remainder of the plate haptic body. Preferably, the connecting member is approximately 1 to 1.5 mm long and is thinner than the plate haptic body.

According to one embodiment, when the accommodating lens is implanted into the capsular bag of the eye, the plate haptics and its loops contact the periphery of the capsular bag and operate to support the optic within the eye and to substantially align and fix the lens into the capsular bag, thereby centering the lens optic along the optical axis of the eye. The flexible projections extend beyond the diameter of the capsular bag and the lateral distal plate extensions contact the periphery of the capsular bag, increasing the contact area of the lens within the bag to provide additional fixation and support to for the lens within the capsular bag. In some embodiments, the distal end of the plate haptic comprises a distal flange 240 that engages the capsular bag and further increases the contact area. The distal end of the plates may be either ticker or thinner than the proximal body of the plate haptic.

As illustrated in FIG. 4, during accommodation the ciliary muscle exerts radial pressure on the ends of the haptics. The longitudinally rigid plate haptics, which naturally vault backwards when placed into the capsular bag, are thus moved centrally and posteriorly towards the optic. Because of the frame, the haptic and its proximal lateral extensions are substantially rigid in the longitudinal direction and they therefore resist bending to the radial force exerted by the ciliary muscle. However, the stretchable thin hinge across the flexible connecting members is less resistant to the pressure from the vitreous cavity, and the optic with this increase in vitreous cavity pressure is thus pushed forward along the axis of the eye, the optic moving forward relative to both the proximal and distal ends of the plate haptics, resulting in accommodation.

The longitudinal length or circumference diameter of the accommodating lens is preferably between 10.0 to 12.0 mm.

The enablements described in detail above are considered novel over the prior art of record and are considered critical to the operation of at least one aspect of the invention and to the achievement of the above described objectives. The words used in this specification to describe the instant embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification: structure, material or acts beyond the scope of the commonly defined meanings. Thus if an element can be understood in the context of this specification as including more than one meaning, then its use must be understood as being generic to all possible meanings supported by the specification and by the word or words describing the element.

The definitions of the words or drawing elements described herein are meant to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one of the elements described and its various embodiments or that a single element may be substituted for two or more elements in a claim.

Changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalents within the scope intended and its various embodiments. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements. This disclosure is thus meant to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted, and also what incorporates the essential ideas.

The scope of this description is to be interpreted only in conjunction with the appended claims and it is made clear, here, that the named inventor believes that the claimed subject matter is what is intended to be patented.

Claims

1. An intraocular lens for insertion into a capsular bag of an eye, the intraocular lens comprising: an optic having a first axis; andat least one haptic coupled to the optic by a flexible connecting member, the haptic operable to engage the capsular bag;wherein a change in radial pressure on the haptic causes the optic to be displaced along the first axis.

2. The intraocular lens of claim 1, wherein the haptic comprises a substantially rigid frame operable to restrict deformation of the haptic in a longitudinal direction.

3. The intraocular lens of claim 2, wherein the rigid frame is operable to substantially permit deformation of the haptic in a traverse direction thereof.

4. The intraocular lens of claim 2, wherein the rigid frame is substantially comprised of at least one of: polymide, PMMA, titanium and prolene.

5. The intraocular lens of claim 1, wherein the haptic comprises lateral flanges extending from the haptic so as to partially surround the optic.

6. The intraocular lens of claim 1, wherein the haptic comprises lateral edges that are substantially tangential to the optic.

7. The intraocular lens of claim 1, wherein the flexible connecting member comprises: a first surface having a first groove; anda second surface opposite the first surface, the second surface and the first groove forming a hinge;wherein, the connecting member is substantially flexible about the hinge.

8. The intraocular lens of claim 7, wherein the hinge substantially facilitates movement of the optic along the first axis.

9. The intraocular lens of claim 7, wherein the connecting member extends substantially radially from the optic to the haptic; and wherein the first groove substantially arcuately traverses the first surface and partially circumscribes the optic.

10. The intraocular lens of claim 7, wherein the connecting member extends substantially radially from the optic to the haptic; and wherein the first groove substantially traverses the first surface substantially tangential to the optic.

11. The intraocular lens of claim 7, wherein the connecting member extends substantially longitudinally from the optic to the haptic; and wherein the first groove laterally traverses the first surface substantially tangential to the optic.

12. The intraocular lens of claim 7, wherein the connecting member extends longitudinally from the optic to the plate haptic; and wherein the first groove substantially arcuately traverses the first surface and partially circumscribes the optic.

13. The intraocular lens of claim 7, wherein the at least two flexible connecting members are substantially parallel to each other.

14. The intraocular lens of claim 1, wherein the flexible connecting member comprises: a first surface having a first groove; anda second surface opposite the first surface, the second surface having a second groove, the second groove and the first groove forming a hinge;wherein, the connecting member is substantially flexible about the hinge.

15. The intraocular lens of claim 14, wherein the hinge substantially facilitates movement of the optic along the first axis.

16. The intraocular lens of claim 1 further comprising at least one projection extending from a distal end of the haptic, the projection operable to engage the capsular bag.

17. The intraocular lens of claim 16, wherein the haptic comprises a substantially rigid frame to restrict deformation of the haptic in a longitudinal direction thereof;wherein the at least one projection is unitarily formed with the rigid frame.

18. The intraocular lens of claim 1, wherein the haptic comprises a peripheral thickness that is different from a main thickness of the haptic.

19. The intraocular lens of claim 16, wherein the haptic further comprises at least one substantially flat protrusion extending from a distal end and adjacent to a base of the projection, the protrusion operable to engage the capsular bag.

20. The intraocular lens of claim 1, wherein the haptic is a plate haptic.