1. Field of the Invention
The present invention relates generally to intraocular lens systems, and more particularly to accommodating intraocular lens systems.
2. Description of the Related Art
The ability of the eye to modify its refractive power for viewing objects of varying distances is termed “accommodation.” Upon relaxation of the ciliary muscle, the zonular fibers, which connect the capsular bag of the lens to the ciliary muscle, pull on the capsular bag around its equator, causing the entire lens to become less convex (i.e., flatten), so that the lens can focus light from objects at a distance. Similarly, contraction of the ciliary muscle (i.e., reduction of the circumference of the ciliary muscle) results in relaxation of the zonular fibers. Correspondingly, the lens equatorial diameter decreases, the lens central thickness increases, and the lens becomes more spherical with an increased curvature of the anterior and posterior lens surfaces. These changes of the shape of the lens result in accommodation by increasing the dioptric power of the lens so as to focus light from nearer objects onto the retina.
Synthetic intraocular lenses implanted in patients for the treatment of cataracts typically do not have the ability to change shape as do natural lenses. Therefore, such patients experienced a degradation of their ability to accommodate. Efforts to develop intraocular lens systems which provide some degree of accommodation have included single optic intraocular lens systems and dual optic intraocular lens systems.
Certain embodiments of the present invention provide an intraocular lens system adapted to be implanted within an eye. The intraocular lens system comprises an anterior optic movable in a forward direction within the eye. The intraocular lens system further comprises at least two anterior haptic arms, each anterior haptic arm having a first end coupled to the anterior optic and a second end adapted to be coupled to the eye. The intraocular lens system further comprises a posterior optic movable in the forward direction within the eye and coupled to the anterior haptic arms. The intraocular lens system further comprises at least one posterior haptic member adapted to be coupled to the eye and coupled to the posterior optic. The anterior haptic arms are responsive to a first forward movement of the posterior optic by actuating a second forward movement of the anterior optic substantially larger than the first forward movement.
Certain other embodiments provide an intraocular lens system comprising a posterior optic adapted to move a first distance in a forward direction. The intraocular lens system further comprises an anterior optic coupled to the posterior optic and adapted to move a second distance in the forward direction in response to the first distance movement of the posterior optic, wherein the second distance is larger than the first distance.
Certain other embodiments provide an intraocular lens system comprising a posterior optic adapted to move a first distance in a forward direction. The intraocular lens system further comprises an anterior optic adapted to move a second distance in the forward direction, wherein the second distance is larger than the first distance.
Certain other embodiments provide a method of facilitating accommodative motion in an intraocular lens system. The method comprises translating forward movement of a posterior optic of the intraocular lens system into forward movement of an anterior optic of the intraocular lens system, thereby providing ocular accommodation.
For purposes of summarizing the present invention, certain aspects, advantages and novel features of the present invention have been described herein above. It is to be understood, however, that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the present invention. Thus, the present invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.
Previous designs of dual optic intraocular lens systems replace the natural lens with an anterior optic and a posterior optic, coupled together by a spring mechanism and implanted within the capsular bag. Such dual optic intraocular lens systems depend on the interaction of the optics with the capsular bag. When the ciliary muscle is relaxed and the zonular fibers are under tension, the capsular bag is pulled at its equator and stretched, thereby bringing the anterior optic and the posterior optic closer together and compressing the spring mechanism. When the ciliary muscle is contracted and the zonular fibers are relaxed, the capsular bag relaxes and the spring mechanism pushes the anterior optic and the posterior optic apart to their equilibrium positions. These relative movements of the anterior and posterior optics provide some measure of accommodation. Such dual optic intraocular lens systems are typically designed to have a high power anterior lens and a combined dioptric power to attempt to achieve a significant accommodation range of several dioptric powers over the range of spacings between the anterior optic and the posterior optic.
There are several drawbacks of such dual optic intraocular lens systems which rely on the interaction of the ocular elements with the capsular bag to provide accommodation. The mechanical properties of the capsular bag are likely to vary with individual, age, and the surgical implantation procedure used, thereby making it a challenge to predict an accommodating outcome for such dual optic intraocular lens systems. Another drawback of such dual optic intraocular lens systems relates to the fact that, unlike for natural lenses, the relaxed state of the system has the two optics spaced apart (i.e., in the near power configuration). The performance of such dual optic intraocular lens systems depends upon the ability of the capsular bag to bring the anterior optic to the specifically designed position close to the posterior optic. The variability of the behavior of the capsular bag therefore results in an inherent variability of the degree of emmetropia achieved by the dual optic intraocular lens system.
Embodiments of the apparatus and method disclosed herein offer a significant improvement over the current dual optic intraocular lens systems by amplifying a limited forward (i.e., in the anterior direction) movement of the posterior optic into a larger forward movement of the high power anterior optic. Accordingly, certain embodiments disclosed herein utilize movement of the high power anterior optic to achieve practical accommodation without the corresponding reliance on the mechanical properties of the capsular bag. As a further advantage, certain embodiments disclosed herein have an emmetropic relaxed state, thereby making the ability of the intraocular lens system to achieve emmetropia substantially independent from the accommodating characteristics of the system.
In certain embodiments, the anterior optic 20 comprises a substantially transparent biocompatible material. Examples of suitable materials include, but are not limited to, PMMA, silicone, and acrylic. As schematically illustrated in
In certain embodiments, the anterior haptic arms 30 comprise a biocompatible material. Examples of suitable materials include, but are not limited to, PMMA, Nitinol, and other biocompatible plastics and metals. The anterior haptic arms 30 and the anterior optic 20 can be formed as a single unit, and for certain such embodiments, the same materials can be used for the anterior haptic arms 30 and the anterior optic 20. In other embodiments, the first end 32 of each anterior haptic arm 30 is mechanically coupled to the anterior optic 20, with exemplary couplings including, but not limited to, glue, pressure, mating post and hole assemblies and interlocking assemblies.
In certain embodiments, the second end 34 of each anterior haptic arm 30 is adapted to be coupled to the eye by placement within the capsular bag. This configuration can be accomplished by making the overall length of the assembly of the anterior optic 20 and the anterior haptic arms 30 approximately equal to the diameter of the capsular bag, which can range from approximately 9 millimeters to approximately 11 millimeters. In certain such embodiments, the overall length between the second ends 34 of the two anterior haptic arms 30 of
In other embodiments, the second end 34 of each anterior haptic arm 30 is adapted to be coupled to other structures of the eye (e.g., the zonular fibers or the ciliary body). Such embodiments can be advantageously used in circumstances in which the capsular bag is absent, or in which the capsular bag is not in the optimal position for the intraocular lens system 10. Certain such embodiments have an overall length of the assembly of the anterior optic 20 and the anterior haptic arms 30 greater than approximately 11 millimeters, while other embodiments have an overall length of this assembly of approximately 13 millimeters.
As described more fully below, the anterior haptic arms 30 of certain embodiments provide sufficient flexibility for substantial forward movement of the anterior optic 20. Sufficient flexibility can be provided by using a shape-memory alloy, such as Nitinol, for the anterior haptic arms 30. Each anterior haptic arm 30 can also comprise one or more notches (shown in
In certain embodiments, the posterior optic 40 comprises a substantially transparent biocompatible material. Examples of suitable materials include, but are not limited to, PMMA, silicone, and acrylic. As schematically illustrated in
In certain embodiments, the posterior haptic member 50 comprises a biocompatible material. Examples of suitable materials include, but are not limited to, PMMA, Nitinol, and other biocompatible plastics and metals. The posterior haptic member 50 and the posterior optic 40 are formed as a single unit in certain embodiments, and the same materials can be used for the posterior haptic member 50 and the posterior optic 40. In other embodiments, the posterior haptic member 50 is mechanically coupled to the posterior optic 40, with exemplary couplings including, but not limited to, glue,. pressure, mating post and hole assemblies, and interlocking assemblies. In certain embodiments, the coupling between the posterior haptic member 50 and the posterior optic 40 is a flexible connection which allows easier and substantial movement of the posterior optic 40 in the forward direction, as compared to a fixed haptic coupling. In the embodiment illustrated in
In certain embodiments, each posterior haptic member 50 is adapted to be coupled to the eye by placement within the capsular bag. This configuration can be accomplished by making the overall length of the assembly of the posterior optic 40 and the posterior haptic members 50 approximately equal to the diameter of the capsular bag, which can range from approximately 9 millimeters to approximately 11 millimeters. In certain such embodiments, the overall length of the assembly of the posterior optic 40 and the posterior haptic members 50 of
In other embodiments, each posterior haptic member 50 is coupled to other structures of the eye (e.g., the zonular fibers or the ciliary body). Such embodiments can be advantageously used in circumstances in which the capsular bag is absent, or in which the capsular bag is not in the optimal position for the intraocular lens system 10. Certain such embodiments have an overall length of the assembly of the posterior optic 40 and the anterior haptic members 50 greater than approximately 11 millimeters, while other embodiments have an overall length of this assembly of approximately 13 millimeters.
In certain embodiments, the posterior haptic members 50 are fixedly coupled to the second ends 34 of the anterior haptic arms 30. In such embodiments, coupling the posterior haptic member 50 to the eye thereby couples the second end 34 of the anterior haptic arm 30 to the eye. For example, the second end 34 of the anterior haptic arm 30 can be imbedded at various locations within the posterior haptic member 50.
In certain embodiments, the posterior optic 40 is coupled to the anterior haptic arms 30 such that forward movement of the posterior optic 40, ostensibly in response to the vitreous pressure of the posterior chamber, moves the anterior haptic arms 30 in the forward direction. In the embodiment schematically illustrated in
Relatively small movements of the posterior optic 40 can yield relatively significant movements of the anterior optic 20. Comparing the equilibrium configuration illustrated by
In the equilibrium configuration of the intraocular lens system 10 shown in
In the displaced configuration of the intraocular lens system 10, as shown in
where m is the movement amplification factor. Thus, depending on the contact position of the edge 42 of the posterior optic 40 with the anterior haptic arm 30, the forward movement of the posterior optic 40 can be amplified by a factor of between approximately 2 and approximately 4 in certain embodiments, and by a factor higher than 4 in other embodiments. For example, for movements of the posterior optic 40 of approximately 0.35 millimeters and a movement amplification factor of approximately 3, a forward movement of the anterior optic 20 of approximately one millimeter can be achieved. For an anterior optic 20 with a power of approximately 30 diopters, this movement of the anterior optic 20 can yield approximately 2 diopters of accommodation. In certain embodiments, the forward movement of the posterior optic 40 is between approximately 0.3 millimeters and approximately 0.5 millimeters.
In certain embodiments, the edge-to-edge length of the anterior haptic arms 30 is larger than the edge-to-edge length of the posterior haptic members 50. The edge-to-edge length of the posterior haptic members 50 is sufficiently short in certain embodiments to be uncoupled or loosely coupled to the eye, so as to allow free forward movement of the posterior haptic members 50 together with the posterior optic 40 itself. The edge-to-edge length of the posterior haptic members 50 of certain embodiments is between approximately 8 millimeters and approximately 10.5 millimeters, and is equal to approximately 9.7 millimeters in other embodiments.
Various embodiments of the present invention have been described above. Although this invention has been described with reference to these specific embodiments, the descriptions are intended to be illustrative of the present invention and are not intended to be limiting. In particular, components, features, or other aspects of the various embodiments described herein can be combined or interchanged with one another in any desirable order, amount, arrangement, or configuration. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the present invention as defined in the appended claims.
This application claims benefit under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 60/447,260, filed Feb. 13, 2003, which is incorporated in its entirety by reference herein.
Number | Name | Date | Kind |
---|---|---|---|
4409691 | Levy | Oct 1983 | A |
4842601 | Smith | Jun 1989 | A |
4892543 | Turley | Jan 1990 | A |
4932966 | Christie et al. | Jun 1990 | A |
4963148 | Sulc et al. | Oct 1990 | A |
4994082 | Richards et al. | Feb 1991 | A |
5152788 | Isaacson et al. | Oct 1992 | A |
5275623 | Sarfarazi | Jan 1994 | A |
5354335 | Lipshitz et al. | Oct 1994 | A |
5443506 | Garabet | Aug 1995 | A |
5522891 | Klaas | Jun 1996 | A |
5728155 | Anello et al. | Mar 1998 | A |
5968094 | Werblin et al. | Oct 1999 | A |
5984962 | Anello et al. | Nov 1999 | A |
6197058 | Portney | Mar 2001 | B1 |
6231603 | Lang et al. | May 2001 | B1 |
6280471 | Peyman et al. | Aug 2001 | B1 |
6423094 | Sarfarazi | Jul 2002 | B1 |
6488708 | Sarfarazi | Dec 2002 | B2 |
6503276 | Lang et al. | Jan 2003 | B2 |
6599317 | Weinschen et al. | Jul 2003 | B1 |
6616691 | Tran | Sep 2003 | B1 |
6645246 | Weinschenk et al. | Nov 2003 | B1 |
20010001836 | Cumming | May 2001 | A1 |
20010012964 | Lang et al. | Aug 2001 | A1 |
20020068971 | Cumming | Jun 2002 | A1 |
20020072795 | Green | Jun 2002 | A1 |
20020116060 | Nguyen et al. | Aug 2002 | A1 |
20020143395 | Skottun | Oct 2002 | A1 |
20020188351 | Laguette | Dec 2002 | A1 |
20020193876 | Lang et al. | Dec 2002 | A1 |
20030109925 | Ghazizadeh et al. | Jun 2003 | A1 |
Number | Date | Country |
---|---|---|
0 337 390 | Oct 1989 | EP |
WO 8404449 | Nov 1984 | WO |
WO 9615734 | May 1996 | WO |
WO 9920206 | Apr 1999 | WO |
WO 0027315 | May 2000 | WO |
WO 0061036 | Oct 2000 | WO |
WO 0066037 | Nov 2000 | WO |
WO 0134067 | May 2001 | WO |
WO 02071983 | Sep 2002 | WO |
WO 03092552 | Nov 2003 | WO |
PCTUS2004003851 | Feb 2004 | WO |
Number | Date | Country | |
---|---|---|---|
20040162612 A1 | Aug 2004 | US |
Number | Date | Country | |
---|---|---|---|
60447260 | Feb 2003 | US |