Abstract:
Intraocular lenses (IOLs) and related methods. One embodiment provides an IOL which includes a lens optic and a pair of haptics. The haptics can be coupled to the lens optic and can cause compression of the lens optic when the IOL is fixated in an eye. The lens optic can have a compressed geometry, an uncompressed geometry including an aberration, and a desired geometry. The compressed geometry can be the desired geometry. The aberration can be astigmatism, coma, or spherical aberration. For instance, the aberration can be astigmatism of about 0.17 D at the spectacle plane and of about 0.25 D at the intraocular lens plane. Moreover, the haptics can define a first axis between the haptics; the lens optic can define a second axis perpendicular to the first axis; and the uncompressed geometry can differ from the compressed geometry in the vicinity of the second axis.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. provisional application Ser. No. 61/153,869, filed on Feb. 19, 2009, the contents which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates to intraocular lenses. More particularly, the present invention relates to intraocular lenses with haptics and methods for offsetting the optical effects caused by optic deformation. 
       BACKGROUND OF THE INVENTION 
       [0003]    The human eye is a generally spherical body defined by an outer wall called the sclera, having a transparent bulbous front portion called the cornea. The lens of the human eye is located within the generally spherical body, behind the cornea. The iris is located between the lens and the cornea, dividing the eye into an anterior chamber in front of the iris and a posterior chamber in back of the iris. A central opening in the iris, called the pupil, controls the amount of light that reaches the lens. Light is refracted by the cornea and by the lens onto the retina at the rear of the eye. The lens is a bi-convex, highly transparent structure surrounded by a thin lens capsule. The lens capsule is supported at its periphery by suspensory ligaments called zonules, which are continuous with the ciliary muscle. The focal length of the lens is changed by the ciliary muscle pulling and releasing the zonules. Just in front of the zonules, between the ciliary muscle and iris, is a region referred to as the ciliary sulcus. 
         [0004]    A cataract condition results when the material of the lens becomes clouded, thereby obstructing the passage of light. To correct this condition, three alternative forms of surgery are generally used, known as intracapsular extraction, extracapsular extraction, and phacoemulsification. In intracapsular cataract extraction, the zonules around the entire periphery of the lens capsule are severed, and the entire lens structure, including the lens capsule, is then removed. In extracapsular cataract extraction and phacoemulsification, only the clouded material within the lens capsule is removed, while the transparent posterior lens capsule wall with its peripheral portion, as well as the zonules, are left in place in the eye. 
         [0005]    Intracapsular extraction, extracapsular extraction, and phacoemulsification eliminate the light blockage due to the cataract condition. The light entering the eye, however, is thereafter defocused due to the lack of a lens. A contact lens can be placed on the exterior surface of the eye, but this approach has the disadvantage that the patient has virtually no useful sight when the contact lens is removed. A preferred alternative is to implant an artificial lens, known as an intraocular lens (IOL), directly within the eye. An intraocular lens generally comprises a disk-shaped, transparent lens optic and two curved attachment arms referred to as haptics. The lens is implanted through an incision made near the periphery of the cornea, which may be the same incision as is used to remove the cataract. An intraocular lens may be implanted in either the anterior chamber of the eye, in front of the iris, or in the posterior chamber, behind the iris. 
         [0006]    An anterior chamber lens is supported by contact of the haptics with a corner, or angle, of the anterior chamber which is formed by the union of the iris and the cornea. In the case of a posterior chamber lens, there are two alternative techniques of support. In the first technique, the intraocular lens and its haptics are placed in the sack-like structure formed by the intact posterior and peripheral walls of the lens capsule. The haptics are compressed slightly against the periphery of the lens capsule and thereby hold the intraocular lens in place. In the second technique, the intraocular lens is placed in front of and outside the lens capsule. The haptics are sandwiched between the iris and the zonules, in the region of the ciliary sulcus, to hold the lens in place. 
         [0007]    During implantation, an intraocular lens can become compressed by the haptics. This can lead to the lens shape becoming distorted; thereby impacting the intended optical quality of the lens. 
       SUMMARY OF THE INVENTION 
       [0008]    Traditional IOL designs have not considered the optical effect of the deformation induced by the mechanical elements that fixate the IOL in the eye. The deformation caused by compression may create aberrations (e.g., astigmatism, coma, etc) in the lens optic that can reduce the optical performance of the lens, especially at larger pupil diameters. The effects of optical surface deformation become more important as lens optics become more precise. Embodiments disclosed herein incorporate a lens optic designed with features, such as surface geometry, refractive index or other features for negating aberrations induced when the lens is in the eye. For example, the lens geometry can be selected geometry in an uncompressed state so that the lens has a desired geometry in a compressed state that is that reduces or eliminates the optical effects of compression in typical IOLs. As another example, the outer geometry of the lens can be selected so that the refractive index of the material is less than or greater the refractive index of the rest of the IOL to produce desired results when the IOL is implanted.) 
         [0009]    Embodiments of a lens optic may include a first surface having a first surface uncompressed geometry in an uncompressed state and a second surface having a first geometry in an uncompressed state. At least one of the first surface uncompressed geometry and the second surface uncompressed geometry may be formed such that the lens optic is substantially free of optical effects when in the compressed state. In some embodiments, the compressed state is due to compression of the lens optic when positioned in an eye compartment. The second geometry may be due to compressive forces exerted by one or more haptics on the lens optic. The lens optic can further comprise an aberration selected to correct astigmatism. In some embodiments, the aberration is based on an anticipated compression of 0.5 mm to 1.0 mm. In some embodiments, the aberration is selected to correct coma. In some embodiments, the aberration is selected to correct a spherical aberration. 
         [0010]    An embodiment of an intraocular lens may include a lens optic and a pair of haptics coupled to the lens optic. The lens optic may have a first surface having a first surface uncompressed geometry in an uncompressed state and a second surface having a second surface uncompressed geometry in an uncompressed state. At least one of the first surface uncompressed geometry and the second surface uncompressed geometry may be formed such that the lens optic is substantially free of optical effects when in the compressed state. In some embodiments, the haptics define a first axis on the lens optic between the haptics and a second axis may be defined on the lens optic at some angle relative to the first axis. The uncompressed geometry of one or more of the first surface and the second surface relative to the first axis may differ from the compressed geometry of the first surface or the second surface about the second axis. The lens optic may have a thinner edge thickness where the edge intersects the second axis than where the edge intersects the first axis. In some embodiments, the uncompressed geometry of one or more of the first surface and the second surface is based on an anticipated compression of the lens optic due to the eye compartment or the haptics so that the lens optic compresses to a desired shape when implanted. 
         [0011]    Embodiments disclosed herein may also be directed to a method of offsetting an optical effect due to deformation of a lens optic. The method may include the steps of identifying an aberration in the eye for which correction is desired, determining an expected amount of compression caused by implanting an intraocular lens into a chamber and selecting an intraocular lens for implantation based on the expected compression. The first surface has a first surface uncompressed geometry and the second surface has a second surface uncompressed geometry when in an uncompressed state. At least one of the first surface and the second surface has a compressed geometry when in a compressed state. The intraocular lens may comprise a lens optic with a first surface and a second surface and a pair of haptics. The first geometry of one or more of the first surface and the second surface may be formed such that the lens optic is substantially free of optical effects when in the compressed state. One or more of the first surface and the second surface may have a first geometry when in an uncompressed state and one or more of the first surface and the second surface may have a second geometry when in a compressed state. 
         [0012]    Additionally, the method can include creating one or more aberrations on one or more of the first surface and the second surface. The aberrations created in the intraocular lens when the lens is in an uncompressed state may offset the optical effects caused by the compression of the lens optic. In some embodiments, the aberration includes one of astigmatism, coma, or spherical aberration. In some embodiments, the aberration is formed to about 0.17 D at the spectacle place and being up to about 0.25 D at the intraocular lens plane. In some embodiments, the haptics define a first axis on the lens optic between the haptics, a second axis is defined at an angle relative to the first axis. The uncompressed geometry differs from the desired geometry about the second axis. 
         [0013]    In some embodiments, determining the amount of compression caused by implanting the intraocular lens into the chamber comprises estimating an amount of compression of the lens optic attributable to compression by the haptics, wherein creating one or more aberrations on one or more of the first surface and the second surface comprises selecting the desired geometry to account for the amount of compression attributable to compression by the haptics. In some embodiments, the method includes forming the lens optic having one or more of the first surface and the second surface with an aspheric curve. 
         [0014]    One advantage to creating a lens having a surface geometry based on an anticipated compressed state may be the ability to create thinner lenses. Thus, instead of making the lens optic thicker to reduce the effect of compression, or reduce the stiffness of the haptics, which could affect how well the IOL remains in place once implanted, embodiments disclosed herein can allow thinner lenses to be implanted without sacrificing optical performance. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0015]    A more complete understanding of the present invention and the advantages thereof may be acquired by referring to the following description, taken in conjunction with the accompanying drawings in which like reference numbers indicate like features. 
           [0016]      FIG. 1  is a perspective view of one embodiment of an intraocular lens; 
           [0017]      FIG. 2  depicts a schematic diagram of one embodiment of an intraocular lens having a convex surface, illustrating axial displacements for the lens; 
           [0018]      FIG. 3  depicts a schematic diagram of one embodiment of an intraocular lens having a convex surface, illustrating axial displacements for the lens with average rigid-body motion removed; 
           [0019]      FIG. 4  depicts a schematic diagram of one embodiment of an intraocular lens having a concave surface, illustrating axial displacements for the lens; 
           [0020]      FIG. 5  depicts a schematic diagram of one embodiment of an intraocular lens having a concave surface, illustrating axial displacements for the lens with average rigid-body motion removed; 
           [0021]      FIG. 6  depicts a schematic diagram of theoretical spherical performance of a lens in a model eye; 
           [0022]      FIG. 7  depicts a spot diagram corresponding to the model eye depicted in  FIG. 6 ; 
           [0023]      FIG. 8  depicts a diagram of the Modulation Transform Function (MTF) for the model eye depicted in  FIG. 6 ; 
           [0024]      FIG. 9  depicts a spot diagram representing the optical performance of an eye showing signs of astigmatism; 
           [0025]      FIG. 10  depicts an MTF diagram showing phakic performance of an exemplary eye showing signs of astigmatism; 
           [0026]      FIG. 11  depicts a spot diagram representing the optical performance of an eye having an intraocular lens positioned therein to correct for astigmatism; 
           [0027]      FIG. 12  depicts an MTF diagram showing phakic performance of an exemplary eye having an intraocular lens positioned therein to correct for astigmatism; 
           [0028]      FIG. 13  depicts a flow chart of one method for improving the optical performance of an intraocular lens; 
           [0029]      FIGS. 14A and 14B  depict views of one embodiment of a lens optic, illustrating an axis where compression force is applied a force axis; 
           [0030]      FIG. 15A  depicts a top view of one embodiment of a lens optic; 
           [0031]      FIGS. 15B and 15C  side views of one embodiment of a lens optic; 
           [0032]      FIG. 15D  depicts a close-up of an aspheric optic side view of the lens optic depicted in  FIG. 15C ; 
           [0033]      FIG. 16A  depicts a perspective view of one embodiment of a lens having an aberration for offsetting the optical effects due to compression; 
           [0034]      FIG. 16B  depicts a cutaway side view along the force axis of the lens depicted in  FIG. 16A ; 
           [0035]      FIG. 16C  depicts a cutaway side view along the bending axis of the lens depicted in  FIG. 16A ; 
           [0036]      FIG. 17A  depicts a perspective view of one embodiment of a lens having an aberration for offsetting the optical effects due to compression; 
           [0037]      FIG. 17B  depicts a cutaway side view along the force axis of the lens depicted in  FIG. 17A ; and 
           [0038]      FIG. 17C  depicts a cutaway side view along the bending axis of the lens depicted in  FIG. 17A . 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    Embodiments of a method and apparatus for offsetting the optical effects caused by compression of the lens and deformation induced by compression of the lens optic or fixation components are disclosed. 
         [0040]    Various embodiments of the disclosure are illustrated in the FIGURES, like numerals being generally used to refer to like and corresponding parts of the various drawings. 
         [0041]    As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present). 
         [0042]    Additionally, any examples or illustrations given herein are not to be regarded in any way as restrictions on, limits to, or express definitions of, any term or terms with which they are utilized. Instead, these examples or illustrations are to be regarded as being described with respect to one particular embodiment and as illustrative only. Those of ordinary skill in the art will appreciate that any term or terms with which these examples or illustrations are utilized will encompass other embodiments which may or may not be given therewith or elsewhere in the specification and all such embodiments are intended to be included within the scope of that term or terms. Language designating such nonlimiting examples and illustrations includes, but is not limited to: “for example”, “for instance”, “e.g.”, “in one embodiment”. 
         [0043]    Embodiments of methods and systems disclosed herein may be used to offset one or more optical effects caused by deformation of the lens optic. 
         [0044]      FIG. 1  depicts a perspective view of one embodiment of intraocular lens  10  comprising optic  11  having surfaces  12  and  14  and haptics  16 . In some embodiments, surfaces  12  and  14  may be convex or concave (e.g., lens optic  11  may have a convex surface  12  and a concave surface  14  or some other configuration). In some embodiments, lens  10  may be formed with each haptic  16  formed from one or more elements. For example,  FIG. 1  depicts haptics  16  with a single wide portion near optic  11 , a bifurcated section distal the wide portion, and a curved outer portion connected to both ends of the bifurcated section. Those skilled in the art will appreciate that other designs for haptics are possible, with each design introducing a unique compressive force on optic  11 . 
         [0045]      FIG. 2  depicts a schematic diagram of one embodiment of intraocular lens  10  depicted in  FIG. 1  and optic  11  having convex surface  12 .  FIG. 2  depicts one embodiment of lens  10  showing axial displacements of convex surface  12 .  FIG. 3  depicts a schematic diagram of the embodiment of intraocular lens  10  depicted in  FIG. 2 , with the average rigid-body motion removed. By removing the effects of average rigid-body motion from lens  10 , substantially all the axial displacement of optic  11  may be due to elastic deformation of optic  11 . 
         [0046]      FIG. 4  depicts a schematic diagram of one embodiment of intraocular lens  10  depicted in  FIG. 1  with optic  11  having concave surface  12 .  FIG. 4  depicts one embodiment of lens  10  showing axial displacements of concave surface  12 .  FIG. 5  depicts a schematic diagram of the embodiment of intraocular lens  10  depicted in  FIG. 4 , with the average rigid-body motion removed. By removing the average rigid-body motion, substantially all the axial displacement of optic  11  associated with concave surface  12  may be due to elastic deformation of optic  11 . 
         [0047]      FIG. 6  depicts a schematic diagram of theoretical spherical performance of lens  10  in a model eye. Light entering model eye  20  (i.e. from the bottom as depicted in  FIG. 6 ) passes through spherical cornea  22 , phakic lens  10  and lens  24  such that the light is ideally focused at a single spot  25  on retinal plate  26  some distance from lens  10 .  FIG. 7  depicts a spot diagram corresponding to model eye  20  depicted in  FIG. 6 . Light focused by a nominal system would produce a very small spot, as shown in  FIG. 7 . The rings in the spot diagram are residual spherical aberration, which will be present in any spherical optical system, the case of a nominal system the spherical aberration would be on the order of 1/25 of a wave.  FIG. 8  depicts a diagram of the Modulation Transfer Function (MTF) for model eye  20 , in which the modulus of the optical transfer function (which is normalized to be between 0 and 1) for a range of spatial frequencies (in cycles per mm). Theoretical curve  40  represents the diffraction limit of the modulus of the optical transfer function for a range of spatial frequencies between 0 and about 508 cycles per mm. Actual curve  42  represents the actual modulus of the optical transfer function for the same range of spatial frequencies. Ideally, actual curve  42  for model eye  20  would equal theoretical curve  40  for all points. 
         [0048]      FIG. 9  depicts a spot diagram representing the optical performance of an eye with a deformed intraocular lens  10 . Instead of spot diagram  30  forming concentric circles, rings  30  have an irregular shape similar to an oval or some other non-circular shape depicting the introduction of astigmatism. Astigmatism is only selected as an example for demonstration purposes. 
         [0049]      FIG. 10  depicts a diagram of the performance of an exemplary eye showing signs of astigmatism for a range of spatial frequencies (in cycles per mm) in an eye with a deformed phakic as described in conjunction with  FIG. 9 . Curve  40  depicts the normalized theoretical modulus of the optical transfer function for a range of spatial frequencies. Curve  42  represents the normalized expected modulus of the optical transfer function for a range of spatial frequencies. Curve  44  represents the normalized actual modulus of the optical transfer function for a range of spatial frequencies. Thus, the effect due to the lens may contribute heavily to the poor optical performance. 
         [0050]      FIG. 11  depicts a spot diagram representing the optical performance of an eye having a spectacle lens. The spectacle lens may focus to form a spot  32  that is more circular than spot  32  depicted in  FIG. 9 . Those skilled in the art will appreciate that the spot diagram depicted in  FIG. 11  represents an improved optical performance of an eye as compared to the spot diagram depicted in  FIG. 9 . 
         [0051]      FIG. 12  depicts a diagram of the phakic performance of an exemplary eye having a spectacle lens for a range of spatial frequencies (in cycles per mm). Curve  40  depicts the normalized theoretical modulus of the optical transfer function over the range of spatial frequencies. Curve  42  represents the normalized expected modulus of the optical transfer function over the range of spatial frequencies. Curve  44  represents the normalized actual modulus of the optical transfer function over the range of spatial frequencies. Curve  44  more closely approximated curve  42 . Those skilled in the art will appreciate that the MTF diagram depicted in  FIG. 12  represents an improved optical performance of an eye than the MTF diagram depicted in  FIG. 10 . 
         [0052]    In the above case, the spectacle lens improves performance for the deformed phakic. Another method for improving the optical performance of an intraocular lens involves offsetting the optical effects due to deformation of the lens optic. Deformation of the lens optic may be due to compression of the lens optic, which is typically the result of implanting the IOL in the capsular bag or the anterior or posterior chambers of the ciliary sulcus. Deformation of the lens optic may also be due to compression of the haptics. Deformation may also be caused by a combination of lens optic compression and the effect of haptic compression on the lens optic. Various features of the IOL, such as geometry, material, optical properties or other features of the lens optic or overall IOL, can be selected so that the lens optic is substantially free of optical effects when in its compressed state. 
         [0053]      FIG. 13  depicts flow chart  100  of one method for improving the optical performance of intraocular lens  10 . In step  102 , one or more aberrations of the eye is identified for correction. Aberrations of the eye include bias, tilt, power (defocus), astigmatism, coma, spherical and trefoil, as well as higher orders of astigmatism, coma and sphericity, and may also include pentafoil, tetrafoil, higher order spherical aberrations and others. 
         [0054]    In step  104 , lens  10  may be selected for placement in the eye. Lens  10  may be selected based on the material used to manufacture lens  10 . Those skilled in the art will appreciate that each lens material may have a unique set of material properties, such as Young&#39;s modulus, bulk modulus, shear modulus, and the like. In some embodiments, lens  10  may be manufactured from a soft plastic material. In one embodiment, an AcrySof® lens manufactured by Alcon Labs of Fort Worth, Tex. may be selected. 
         [0055]    In step  106 , the eye chamber into which lens  10  is to be implanted may be measured. In some embodiments, measuring may include measuring a diameter. Measuring the diameter may be necessary because the chamber has an associated amount of variation. For example, it may be necessary to measure the diameter of the anterior chamber of the ciliary sulcus prior to implantation of lens  10  because the anterior chamber has a relatively large variation in diameter. Measuring the eye chamber may also include other measurements. 
         [0056]    Those skilled in the art will appreciate that steps  104  and  106  may be performed in either order. That is, the eye chamber into which lens  10  is to be implanted may be measured before lens  10  is selected or lens  10  may be selected before the eye chamber is measured. For example, the pupil diameter, size of the eye chamber, or some other characteristic of the eye or eye chamber may affect the type of IOL  10  to be used in the eye. 
         [0057]    In step  108 , the amount of expected compression exerted on lens optic  11  by the chamber may be determined. Determining the amount of compression may involve predicting the compression due to the difference between the outer diameter of lens optic  11  and the inner diameter of the eye chamber. In some embodiments, determining the amount of compression may involve determining an expected range of compression. The compression in the anterior chamber may range from about 0.5 mm to about 1.0 mm. 
         [0058]    In some embodiments, step  108  of determining the amount of compression on lens optic  11  may involve predicting the compression due to one or more characteristics of haptics  16 . In some embodiments, one or more of the thickness, diameter, shape or length of haptics  16  may affect the amount of compression exerted on lens optic  11 . In some embodiments, the angle of connection of haptics  16  to lens optic  11 , the location of the attachment point, the means by which haptics  16  are connected to lens optic  11 , the area formed at the attachment point, or some other characteristic of how haptics  16  are coupled to lens optic  11  may affect the compression of lens optic  11  in the eye chamber. 
         [0059]    In some embodiments, one or more numerical programs, finite element analysis (FEA), ray-tracing or other methods may be used to predict the deformation of lens optic  11 . In one embodiment, lens optics  11  having different geometries or aberrations may be positioned in various model eyes and spot diagrams or MTF diagrams may be generated to predict the deformation of lens optic  11 . 
         [0060]    In step  110 , intraocular lens  10  may be created such that when lens  10  is implanted in the eye chamber, lens optic  11  will deform into a desired compressed geometry. Intraocular lens  10  may be created to correct for astigmatism, coma, spherical aberration, or some other deformation. Intraocular lens  10  may be created to correct for a higher-order deformation. Creating lens  10  may include determining the amount of deformation that needs to be introduced into lens  10  to offset the optical effects of compression of the lens optic or compression of the haptics or both. In some embodiments, determining the amount of deformation that needs to be introduced to offset an optical effect includes identifying a bending axis. Turning briefly to  FIG. 14A , this figure depicts a perspective view of one embodiment of optic  11  having bending axis b-b. Bending axis b-b may be the result of the construction of optic  11  or the application of forces F on optic  11  or some combination. Bending of optic  11  may impart an aberration onto optic  11  of lens  10 .  FIG. 14B  depicts a top view of one embodiment of optic  11 , showing bending axis b-b and force axis f-f. In some embodiments, force axis f-f is perpendicular to bending axis b-b. The angle and/or value of forces F applied on optic  11  may determine the type and value of an aberration on surface  12  or  14  of optic  11 . 
         [0061]    Embodiments of intraocular lens  10  may be created such that any corrective deformation is introduced on posterior surface  12  and/or anterior surface  14  of lens optic  11 . Aberrations on surface  12  and/or surface  14  may be symmetric or asymmetric to offset an effect of compression.  FIG. 15A  depicts one embodiment of optic  11  with bending axis b-b perpendicular to force axis f-f.  FIGS. 15B and 15C  depict a side view of optic  11  depicted in  FIG. 15A .  FIG. 15B  depicts a cutaway side view along axis f-f and  FIG. 15C  depicts a side view along axis b-b. Surface  12  contains an aspheric component in this embodiment.  FIG. 15B  depicts a side view of the lens perpendicular to the force axis and shows how the edge of the optic of a toric lens thins to accommodate the steep axis.  FIG. 15C  depicts a side view of the lens perpendicular to the bending axis. An aspheric curve may be useful for focusing light and may be formed on either surface  12  or  14  or both.  FIG. 15D  depicts a close-up of an aspheric optic side view. As shown in  FIGS. 15A-15D , embodiments of optic  11  may have surface  12  or  14  with a constant profile, may be symmetric about an axis, may have regions of differing profiles, or some combination thereof. 
         [0062]    The force applied on axis f-f may determine the effect on optical performance of optic  11 . The curvature, shape, thickness or other characteristic of surface  14  or  12  of optic  11  may be based on a force F applied to optic  11 . Thus, for the same correction but anticipating different compression rates, different lenses  10  may be created. In some embodiments, a set of lenses  10  for a patient may be created having different surfaces  12  and  14 . For example, a first lens  10  may be created based on an anticipated compression of 0.5 mm and a second lens may be created based on an anticipated compression of 1.0 mm. A set of lenses may be created based on an expected deformation. For example, a first lens  10  may have surface  12  with a selected thickness and a second lens  10  may have surface  12  with a selected thickness. In some embodiments, a set of lenses  10  may be created having aberrations on surface  12 , surface  14 , or some combination. 
         [0063]      FIG. 16A  depicts a perspective view of one embodiment of lens  10  having optic  11  and haptics  16 , showing surface  12 . In  FIG. 16A , bending axis b-b is shown perpendicular to force axis f-f defined by haptics  16 . However, bending axis b-b and force axis f-f are not so constrained, and each may depend on the construction of optic  11 , haptics  16 , or lens  10 .  FIG. 16A  further depicts optic  11  having a thinner cross-section at the edge near bending axis b-b as compared to the area near force axis f-f.  FIG. 16B  depicts a cutaway side view along force axis f-f (i.e., perpendicular to bending axis b-b) of lens  10  depicted in  FIG. 16A .  FIG. 16C  depicts a cutaway side view along axis b-b (i.e., perpendicular to axis f-f) of lens  10  depicted in  FIG. 16A . The uncompressed geometries of surfaces  12  and  14  of lenses  10  depicted in  FIGS. 16A-16C  may be compressed during positioning in the eye compartment to offset the deformation such that lens  10  provides a desired optical performance. 
         [0064]      FIG. 17A  depicts a perspective view of one embodiment of lens  10  having optic  11  and haptics  16 . In  FIG. 17A , bending axis b-b is shown perpendicular to force axis f-f defined by haptics  16 . However, bending axis b-b and force axis f-f are not so constrained, and each may depend on the construction of optic  11 , haptics  16 , or lens  10 .  FIG. 17A  further depicts optic  11  having a thicker cross-section near bending axis b-b as compared to the area near force axis f-f.  FIG. 17B  depicts a cutaway side view along force axis f-f (i.e., perpendicular to bending axis b-b) of lens  10  depicted in  FIG. 17A .  FIG. 17C  depicts a cutaway side view along force axis f-f (i.e., perpendicular to bending axis b-b) of lens  10  depicted in  FIG. 17A . The uncompressed geometries of surfaces  12  and  14  of lenses  10  depicted in  FIGS. 17A-17C  may be compressed during positioning in the eye compartment to offset the deformation such that lens  10  provides a desired optical performance. 
         [0065]    A comparison of optic  11  for  FIGS. 16C and 17C  shows that although surface  12  for may be substantially the same along either axis, surface  14  may have a steeper curve such that the outer edges of optic  11  are thicker. Thus, optic  11  depicted in  FIG. 16B  may be thicker near the edges than optic  11  depicted in  FIG. 17B  but optic  11  (as depicted in  FIG. 16C ) may be thinner around the edge than optic  11  (as depicted in  FIG. 17C ). Those skilled in the art will appreciate that the thickness of optic  11 , the position or orientation of bending axis b-b and force axis f-f, and aberrations may be formed on either surface  12  or  14  or both of optic  11 , may be symmetric or asymmetric with respect to an axis or surface, and may be used in combination for offsetting the effects of compression on optic  11 . The edge thickness of lens optic  11  can follow a pattern such as a sine wave with the thickest portions at the force axis and the thinnest portions at the bending axis. The edge of lens optic  11  can also follow other patterns and need not be symmetric. 
         [0066]    Returning briefly to  FIG. 10 , in some embodiments, a method for improving the optical performance of an intraocular lens may include step  112  of testing the lens. Testing the lens may involve placing lens  10  in a model eye and testing the optical performance. Testing lens  10  may involve placing lens  10  in the eye and testing the optical performance. Other testing may be possible to ensure deformed lens  10  provides a desired optical performance. 
         [0067]    In some embodiments of a method for implanting lens  10  in an eye chamber, a set of lenses may be created to correct an aberration and each lens  10  may be created based on a predicted compression. During surgery, the surgeon may implant a first lens  10  having a first uncompressed geometry and then determine if lens  10  adequately corrects the aberration. If lens  10  does not correct the aberration, the surgeon may remove lens  10  and try a larger or smaller lens until a desired lens  10  is implanted in the eye compartment. 
         [0068]    Although embodiments have been described in detail herein, it should be understood that the description is by way of example only and is not to be construed in a limiting sense. It is to be further understood, therefore, that numerous changes in the details of the embodiments and additional embodiments will be apparent to, and may be made by, persons of ordinary skill in the art having reference to this description. It is contemplated that all such changes and additional embodiments are within scope of the claims below and their legal equivalents.