Patent Publication Number: US-2017348091-A1

Title: Dual region accommodating intraocular lens devices, systems, and methods

Description:
TECHNICAL FIELD 
     This disclosure relates generally to the field of ophthalmic lenses and, more particularly, to electro-active ophthalmic lenses. 
     BACKGROUND 
     The human eye provides vision by transmitting light through a clear outer portion called the cornea, and focusing the image by way of a crystalline lens onto a retina. The quality of the focused image depends on many factors including the size and shape of the eye, and the transparency of the cornea and the lens. When age or disease causes the lens to become less transparent, vision deteriorates because of the diminished light that can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. Presently, cataracts are treated by surgical removal of the affected lens and replacement with an artificial intraocular lens (“IOL”). Cataract extractions are among the most commonly performed operations in the world. 
     In the natural lens, distance and near vision is provided by a mechanism known as accommodation. The natural lens is contained within the capsular bag and is soft early in life. The bag is suspended from the ciliary muscle by the zonules. Relaxation of the ciliary muscle tightens the zonules, and stretches the capsular bag. As a result, the natural lens tends to flatten. Tightening of the ciliary muscle relaxes the tension on the zonules, allowing the capsular bag and the natural lens to assume a more rounded shape. In this way, the natural lens can focus alternatively on near and far objects. 
     As the lens ages, it becomes harder and is less able to change its shape in reaction to the tightening of the ciliary muscle. Furthermore, the ciliary muscle loses flexibility and range of motion. This makes it harder for the lens to focus on near objects, a medical condition known as presbyopia. Presbyopia affects nearly all adults upon reaching the age of 45 to 50. 
     One approach to providing presbyopia correction is the use of an ophthalmic lens, such as an IOL. Single focal length or monocular IOLs have a single focal length or single power; thus, single focal length IOLs cannot accommodate, resulting in objects at a certain point from the eye being in focus, while objects nearer or further away remain out of focus. Single focal length IOLs generally do not require power to function properly. An improvement over the single focal length IOL is an accommodating IOL, which can actually change focus by movement (physically deforming and/or translating within the orbit of the eye) as the muscular ciliary body reacts to an accommodative stimulus from the brain, similar to the way the natural crystalline lens focuses. Such accommodating IOLs are generally made from a deformable material that can be compressed or distorted to adjust the optical power of the IOL over a certain range using the natural movements of eye&#39;s natural zonules and the ciliary body. In some instances, the accommodative IOL includes an electro-active element that has an adjustable optical power based on electrical signals controlling the element, so that the power of the lens can be adjusted based on the patient&#39;s physiologic accommodation demand. 
     The various components of an electro-active or electrically actuated IOL, however, often create an undesirably large implant that is difficult to implant in the eye through a small incision. A large incision can result in surgical complications such as vision loss secondary to scarring or trauma to ocular tissues. Moreover, an electro-active IOL requires power to function correctly, rendering patients vulnerable to poor visual quality in the case of a non-operational IOL experiencing a power or system failure. 
     The devices, systems, and methods disclosed herein overcome one or more of the deficiencies of the prior art. 
     SUMMARY 
     In one exemplary aspect, the present disclosure is directed to an implantable accommodative IOL device for insertion into an eye of a patient, the device comprising an active region and a passive region. The active region has a first thickness and a first refractive index. The active region comprises an electrically responsive optical lens having variable optical power. In one aspect, the passive region is disposed at a periphery of the active region. In one aspect, the passive region has a second thickness and a second refractive index, and the second refractive index is different than the first refractive index. In one aspect, a light beam passing through the active region has a phase difference from the light beam passing through the passive region. 
     In one aspect, the active region comprises a circular disc. In another aspect, the passive region comprises an annular ring disposed circumferentially around the active region. In one aspect, the first thickness is different than the second thickness. In one aspect, the first thickness tapers from a central area to a peripheral area of the active region. In one aspect, the second thickness tapers from a central area to a peripheral area of the passive region. 
     In one aspect, the active region and the passive region have the same optical power when accommodative IOL device is in an unpowered state. 
     In one aspect, the phase difference results from the difference between the first refractive index and the second refractive index. 
     In one aspect, the active region and the passive region have matching focal points. 
     In one aspect, a peripheral edge of the passive region is configured to contact the lens capsule. In another aspect, a peripheral edge of the passive region is configured to reside in the eye sulcus. In one aspect, the passive region includes an external diameter or haptics on the periphery sized to match an internal diameter of an equatorial region of the lens capsule in the eye. 
     In one aspect, the accommodative IOL device includes a housing configured to hold electrical components and connections to the active region. 
     In one aspect, the active region comprises tunable optics technology. 
     In one exemplary aspect, the present disclosure is directed to an implantable accommodative IOL device for insertion into an eye of a patient, the device comprising an active region and a passive region. In one aspect, the active region is shaped as a disc having a first thickness and first refractive index, and the active region comprising an electrically tunable lens having variable optical power. The passive region is shaped as an annular ring disposed circumferentially around the active region, the passive region has a second thickness and a second refractive index, and the second thickness is different than the first thickness. In one aspect, a light beam passing through the active region has a phase difference from the light beam passing through the passive region. 
     In one aspect, the first refractive index is different than the second refractive index. 
     In one aspect, the second thickness tapers from a central area to a peripheral area of the passive region. 
     In one aspect, the active region and the passive region have the same optical power when accommodative IOL device is in an unpowered state. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory in nature and are intended to provide an understanding of the present disclosure without limiting the scope of the present disclosure. In that regard, additional aspects, features, and advantages of the present disclosure will be apparent to one skilled in the art from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate embodiments of the devices and methods disclosed herein and together with the description, serve to explain the principles of the present disclosure. 
         FIG. 1  is a diagram of a cross-sectional side view of an eye. 
         FIG. 2  illustrates a front view of an exemplary accommodative IOL device according to one embodiment consistent with the principles of the present disclosure. 
         FIG. 3  illustrates a cross-sectional view of the exemplary accommodative IOL device shown in  FIG. 2  along the line  3 - 3 . 
         FIG. 4A  illustrates a cross-sectional view of an exemplary accommodative IOL device according to another embodiment consistent with the principles of the present disclosure. 
         FIG. 4B  illustrates a cross-sectional view of the exemplary accommodative IOL device shown in  FIG. 4A  positioned within the eye in a manner consistent with the principles of the present disclosure. 
         FIG. 5A  illustrates a cross-sectional view of an exemplary accommodative IOL device according to another embodiment with the principles of the present disclosure. 
         FIG. 5B  illustrates a cross-sectional view of the exemplary accommodative IOL device shown in  FIG. 5A  according to another embodiment with the principles of the present disclosure. 
         FIG. 6  illustrates a perspective view of an exemplary accommodative IOL device according to an embodiment of the present disclosure. 
         FIG. 7  illustrates a cross-sectional view of the exemplary accommodative IOL device shown in  FIG. 6  implanted within the eye according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is intended. Any alterations and further modifications to the described devices, instruments, methods, and any further application of the principles of the present disclosure are fully contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. For the sake of brevity, however, the numerous iterations of these combinations will not be described separately. For simplicity, in some instances the same reference numbers are used throughout the drawings to refer to the same or like parts. 
     The present disclosure relates generally to devices, systems, and methods for use in alleviating ophthalmic conditions, including visual impairment secondary to presbyopia, cataracts, and/or macular degeneration. As described above, electrically actuated accommodative intraocular lens (“IOL”) devices have the risk of becoming nonoperational or providing poor visual quality in the case of a power or system failure. Embodiments of the present disclosure comprise accommodating IOL devices configured to correct for far- and/or near-sighted vision and to provide good image quality and extended depth of field (“EDOF”) capabilities even in cases of system failure. In some embodiments, the accommodative IOL devices described herein provide good visual quality by maintaining monofocal vision quality and providing extended depth of field even in an unpowered situation. The accommodative IOL devices described herein are configured to provide clear corrective vision and high image quality to patients having various visual deficits and various pupil sizes. 
     In some embodiments, the accommodating IOL devices described herein include an electro-active optical component and a passive optical component that are separable and distinct parts of the device. Such embodiments may facilitate implantation through a smaller incision than a conventional monolithic electro-active accommodative implant. In some instances, the accommodating IOL devices described herein can be implanted in the eye to replace a diseased lens (e.g., an opacified natural lens of a cataract patient). In other instances, the accommodating IOL devices described herein may be implanted in the eye sulcus  32  (shown in  FIG. 1 ) anterior to the natural lens. In some embodiments, the accommodating IOL devices described herein include multiple optical components that may be configured to complement each other and to cooperate to enhance the patient&#39;s vision while being implanted in different regions of the eye. In some embodiments, the embodiments described herein comprise features described in U.S. Provisional Applications XXX (PAT056414, 45463.461) and XXX (PAT056415, 45463.462), filed XXXX, which are incorporated by reference herein in their entirety. 
       FIG. 1  is a diagram of an eye  10  showing some of the anatomical structures related to the surgical removal of cataracts and the implantation of IOLs. The eye  10  comprises an opacified lens  12 , an optically clear cornea  14 , and an iris  16 . A lens capsule or capsular bag  18 , located behind the iris  16  of the eye  10 , contains the opacified lens  12 , which is seated between an anterior capsule segment or anterior capsule  20  and a posterior capsular segment or posterior capsule  22 . The anterior capsule  20  and the posterior capsule  22  meet at an equatorial region  23  of the lens capsule  18 . The eye  10  also comprises an anterior chamber  24  located in front of the iris  16  and a posterior chamber  26  located between the iris  16  and the lens capsule  18 . 
     A common technique of cataract surgery is extracapsular cataract extraction (“ECCE”), which involves the creation of an incision near the outer edge of the cornea  14  and an opening in the anterior capsule  20  (i.e., an anterior capsulotomy) through which the opacified lens  12  is removed. The lens  12  can be removed by various known methods including phacoemulsification, in which ultrasonic energy is applied to the lens to break it into small pieces that are promptly aspirated from the lens capsule  18 . Thus, with the exception of the portion of the anterior capsule  20  that is removed in order to gain access to the lens  12 , the lens capsule  18  remains substantially intact throughout an ECCE. The intact posterior capsule  22  provides a support for the IOL and acts as a barrier to the vitreous humor within the vitreous chamber. Following removal of the opacified lens  12 , an IOL may be implanted within the lens capsule  18 , through the opening in the anterior capsule  20 , to restore the transparency and refractive function of a healthy lens. The IOL may be acted on by the zonular forces exerted by a ciliary body  28  and attached zonules  30  surrounding the periphery of the lens capsule  18 . The ciliary body  28  and the zonules  30  anchor the lens capsule  18  in place and facilitate accommodation, the process by which the eye  10  changes optical power to maintain a clear focus on an image as its distance varies. 
       FIG. 2  illustrates a front view of an exemplary accommodative IOL device  100  according to one embodiment consistent with the principles of the present disclosure.  FIG. 3  illustrates a cross-sectional view of the exemplary accommodative IOL device shown in  FIG. 2  along the line  3 - 3 . The accommodating IOL devices described herein are configured to provide clear vision and accommodation capability using an electro-active or active component in addition to a passive component. In exemplary embodiments disclosed herein, the accommodative IOL device  100  comprises a circular and at least partially flexible disc configured to be implanted in the lens capsule  18  or the eye sulcus  32 . As shown in  FIGS. 2 and 3 , the accommodative IOL device  100  is shaped as a generally circular disc comprising an active region  105  and a passive region  110 . In some embodiments, the active region  105  and the passive region  110  comprise a single lens. In other embodiments, for example as shown in  FIG. 4A , the active region  105  and the passive region  110  form separate optical components that are shaped and configured to couple together. 
     In the pictured embodiment, the active region  105  occupies a central position of the disc, and the passive region  110  occupies a peripheral region of the disc. The active region  105  is shaped and configured as a generally circular area. In other embodiments, the active region  105  may have any of a variety of shapes, including for example rectangular, ovoid, oblong, and square. In some embodiments, the active region  105  includes a refractive index that is different than the refractive index of the passive region  110 . The active region  105  includes a thickness T 1  that may range from 0.2 mm to 2 mm. For example, in one exemplary embodiment, the thickness T 1  of the active region  105  may be 0.6 mm. In some embodiments, the thickness T 1  of the active region  105  varies from the center of the active region  105  to the periphery of the active region  105 . For example, in some embodiments, the active region  105  may taper in thickness from its center to its periphery. 
     The electro-active or active region  105  may comprise any of a variety of materials having optical properties that may be altered by electrical control. The active region  105  comprises an electro-active element that can provide variable optical power via any available tunable optics technology including, by way of non-limiting example, moving lenses, liquid crystals, and/or electro-wetting. Although the alterable properties described herein typically include refractive index and optical power, embodiments of the invention may include materials having other alterable properties, such as for example, prismatic power, tinting, and opacity. The properties of the materials may be affected and controlled electrically, physically (e.g., through motion), and/or optically (e.g., through light changes). The active region  105  has an adjustable optical power based on electrical input signals controlling the region, so that the power of the accommodative IOL device  100  can be adjusted based on the patient&#39;s sensed or inputted accommodation demand. The accommodative IOL device  100  may include control circuitry, power supplies, and wireless communication capabilities. In some embodiments, this componentry may be packaged in a biocompatible material and/or sealed electronic packaging. 
     The passive region  110  is shaped and configured as an annular ring encircling the active region  105 . The passive region  110  includes a refractive index that is different than the refractive index of the active region  105 . In some embodiments, the passive region  110  includes a thickness T 2  that is different than the thickness T 1  of the active region. The thickness T 2  may range from 0.2 mm to 2 mm. For example, in one exemplary embodiment, the thickness T 2  of the passive region  110  may be 0.6 mm. In some embodiments, as shown in  FIG. 3 , the thickness T 2  of the passive region  110  varies from the center  113  of the passive region  110  to the periphery  114  of the passive region  110 . For example, in some embodiment, the passive region  110  may taper in thickness from its center  113  to its periphery  114 . In general, the passive region  110  is formed of relatively more flexible materials than the active region  105 . In the pictured embodiment, the passive region  110  of the accommodative IOL device comprises atraumatic edges  115  at the periphery  114  configured to be positioned within the lens capsule  18  without inadvertently damaging the lens capsule  18  or other ocular cells. 
     Although an outer diameter D 1  of the active region  105  is shown as substantially smaller than an outer diameter D 2  of the passive region  110  in the pictured embodiment, the outer diameter D 1  of the active region  105  may be sized larger relative to an outer diameter D 2  of the passive region  110  in other embodiments. For example, in other embodiments, the outer diameter D 1  of the active region  105  may be almost as large as the outer diameter D 2  of the passive region  110 . In various embodiments, the outer diameter D 1  of the active region  105  may range from 3 mm to 6 mm, and the outer diameter D 2  of the passive region  110  may range from 6 mm to 12 mm. For example, in one exemplary embodiment, the outer diameter D 1  of the active region  105  may be 3 mm, and the outer diameter D 2  of the passive region  110  may be 6 mm. 
     The accommodative IOL device  100  is designed and optimized to have matching focuses (or matching focal points) for both the active region  105  and the passive region  110  to provide a focused image on the retina  11  for far objects for all pupil sizes. As the object draws closer to the eye  10 , the optical power of the active region  105  may be adjusted in response to the input signal (e.g., the electrical input signal) to keep the image focused on the retina  11 . This provides accommodation to the patient in a similar manner as a healthy natural crystalline lens. 
     In some embodiments, the active region  105  may be associated with several other components designed to power and control the active region, as shown in  FIG. 6 . If the active region  105  cannot be powered due to, by way of non-limiting example, a system failure or an empty battery, the active region  105  is shaped and configured to act like a passive or monofocal lens. In an exemplary embodiment, the unpowered active region  105  has the same optical power as the passive region  110 . However, the active region  105  may perform as a passive lens having a different optical power than the passive region  110  because of thickness and refractive index differences between the two regions. In particular, as shown in  FIG. 3 , the light beams  120  passing through the active region  105  and the light beams  125  passing through the passive region  110  will have a phase difference because of these thickness and refractive index differences. This creates an optical effect similar to the Alcon trapezoidal phase shift lens, which includes optical features described in U.S. Pat. No. 8,241,354, entitled “AN EXTENDED DEPTH OF FOCUS (EDOF) LENS TO INCREASE PSEUDO-ACCOMMODATION BY UTILIZING PUPIL DYNAMICS,” which is incorporated herein by reference. As described in that patent, a linear change in the phase shift imparted to incoming light as a function of radius (referred to herein as a “trapezoidal phase shift”) can adjust the effective depth of focus of the accommodative IOL device  100  for different distances and pupil sizes. This phase difference can be defined as the difference in wavefront in units of waves (Δw): 
     
       
         
           
             
               Δ 
                
               
                   
               
                
               w 
             
             = 
             
               
                 
                   
                     ( 
                     
                       
                         n 
                         a 
                       
                       - 
                       
                         n 
                         1 
                       
                     
                     ) 
                   
                    
                   
                     T 
                     1 
                   
                 
                 - 
                 
                   
                     ( 
                     
                       
                         n 
                         p 
                       
                       - 
                       
                         n 
                         1 
                       
                     
                     ) 
                   
                    
                   
                     T 
                     2 
                   
                 
               
               wavelength 
             
           
         
       
     
     where n a  is the refractive index of the active region  105 , n p  is the refractive index of the passive region  110 , n 1  is the refractive index of the surrounding medium, T 1  is the thickness of the active region  108 , and T 2  is the thickness of the passive region  110 . In this manner, the trapezoidal phase shift provides different apparent depth of focus depending on pupil size, allowing the image to change as a result of changes in light conditions. This in turn provides slightly different images for conditions in which one would be more likely to be relying on near or distance vision, allowing the patient&#39;s visual function to better operate under these conditions, a phenomenon known as “pseudo-accommodation.” In particular, the waves having phase differences will interfere, thereby creating extension of the depth of field and a smooth continuity of visual extension. 
     Thus, the phase difference between the two regions (i.e., the active region  105  and the passive region  110 ) creates an extended depth of field for the patient that allows the patient to have a range of vision in a situation where the active region  105  cannot receive power or is otherwise malfunctioning. In the case of a system failure or power failure to the active region  105 , the accommodative IOL device  100  will continue to have monofocal IOL performance and to provide an extended depth of field to the patient. 
     In some embodiments, in its expanded condition, the accommodative IOL device  100  comprises a substantially circular device, as shown in  FIGS. 4B and 5B , configured to be self-stabilized within the eye  10  (e.g., within the lens capsule  18  or the sulcus  32 ). The passive region may be shaped and configured to maintain the natural circular contour of the lens capsule  18  and to stabilize the lens capsule  18  in the presence of compromised zonular integrity when the accommodative IOL device  100  is positioned in the eye  10 . In some embodiments, the passive region  110  comprises an annular ring with a substantially circular shape configured to match the substantially circular cross-sectional shape of the lens capsule  18  (shown in  FIG. 1 ) when the lens capsule  18  is divided on a coronal plane through an equatorial region  23 . In some embodiments, the device  100  may taper from the active region  105  towards a peripheral edge  115 . The peripheral edge  115  comprises the outermost circumferential region of the accommodative IOL device  100 . In some embodiments, the accommodative IOL device  100  may taper toward its peripheral edge  115  to facilitate stabilization of the accommodative IOL device  100  inside the lens capsule  18  and/or the eye sulcus  32 . This may allow the accommodative IOL device  100  to be self-stabilized and self-retained in the eye  10  (i.e., without the use of sutures, tacks, or a manually held instrument). In some embodiments, the angle of the taper from the active region  105  towards the peripheral edges  115  is selected to substantially match the angle of the equatorial region  23  in the lens capsule  18 , thereby facilitating self-stabilization of the accommodative IOL device  100  within the eye  10 . 
       FIG. 4A  illustrates a cross-sectional view of an exemplary accommodative IOL device  150  according to another embodiment consistent with the principles of the present disclosure. The accommodating IOL device  150  is configured to provide clear vision and accommodation capability using an electro-active or active component in addition to a passive component. The accommodative IOL device  150 , like the accommodative IOL device  100  described above, may be used to replace the opacified natural lens  12  of cataract patients and provide the patient with clear vision and enhanced accommodative ability. 
     As shown in  FIGS. 4A and 4B , the accommodative IOL device  150  comprises an electro-active or active element  155  and a passive element  160 . Except for the differences described below, the active element  155  may have substantially similar properties to the active region  105  described above with reference to  FIGS. 2 and 3 . Except for the differences described below, the passive element  160  may have substantially similar properties to the passive region  110  described above with reference to  FIGS. 2 and 3 . Unlike in the accommodative IOL device  100 , where the active region  105  and the passive region  110  are part of a single, monolithic optical component, the active element  155  and the passive element  160  of the accommodative IOL device  150  comprise two individual and separable optical components. 
     As shown in  FIGS. 4A and 4B , the active element  155  and the passive element  160  form separate optical components or regions that are shaped and configured to function together. In the pictured embodiment, both the active element  155  and the passive element  160  are shaped and configured as generally circular optical components that allow for the passage of light beams through the accommodative IOL device  150  toward the retina  11 . In other embodiments, the active element  155  may have any of a variety of shapes, including for example rectangular, ovoid, oblong, and square. In some embodiments, the active element  155  may be associated with several other components designed to power and control the active element, as shown in  FIG. 6 . Although an outer diameter D 3  of the active element  155  is shown as smaller than an outer diameter D 4  of the passive element  160  in the pictured embodiment, the outer diameter D 3  of the active element  155  may be almost as large as an outer diameter D 4  of the passive element  160  in other embodiments. In particular, the optical performance of embodiments having more flexible active elements  155  may benefit from having active elements  155  that are sized to be larger than the passive elements  160 . 
       FIG. 4B  illustrates a cross-sectional view of the exemplary accommodative IOL device  150  shown in  FIG. 4A  positioned within the eye in a manner consistent with the principles of the present disclosure. In the pictured embodiment, the accommodative IOL device  150  comprises an at least partially flexible device configured to be implanted in the lens capsule  18  or the eye sulcus  32  (i.e., the area between the iris  16  and the lens capsule  18 ). In general, the passive element  160  is relatively more flexible than the active element  155 . In one embodiment, the passive element  160  is a large diameter, foldable, relatively soft lens, while the active element  155  is a relatively rigid device having a smaller diameter than the passive element  160 . 
     The two-element accommodative IOL device  150  can reduce the overall incision size during implantation in the eye  10 . In particular, the two-element characteristic of the accommodative IOL device  150  allows the surgeon to implant the two lenses (i.e., the active element  155  and the passive element  160 ) one after another. Each lens or element would have a smaller volume individually than an accommodative IOL device that included both the passive and active elements within a single, monolithic structure. Thus, the two-element accommodative IOL device  150  described herein would require a smaller incision than would a monolithic IOL device. 
     In the pictured embodiment shown in  FIGS. 4A and 4B , the active element  155  is positioned posterior to the passive element  160  within the lens capsule  18  of the eye  10 . In other embodiments, as shown in  FIGS. 5A and 5B , the accommodative IOL device  150  may be positioned within the eye such that the active element  155  is positioned anterior to the passive element  160  within the eye  10  (i.e., closer to the anterior chamber  24  of the eye  10 ). In both instances, the active element  155  and the passive element  160  are positioned to be aligned along a central axis CA extending perpendicularly through a central region  165  of the device  150 . In addition, in some embodiments, the accommodative IOL device  150  may be implanted within the eye sulcus  32 , the area between the iris  26  and the lens capsule  18 . In other instances, the active element  155  and the passive element  160  may be positioned within separate regions of the eye  10 . For example, in some instances, the active element  155  may be implanted within the eye sulcus  32  while the passive element  160  is implanted within the lens capsule  18 . In another instance, the active element  155  may be implanted within the lens capsule  18  while the passive element  160  is implanted within the eye sulcus  32 . The active component  155  and the passive component  160  do not necessarily need to be implanted into the eye  10  at the same time. The active component  155  and the passive component  160  may be implanted within the eye  10  sequentially during the same ophthalmic procedure, or may be implanted into the eye  10  in separate procedures, which may occur at different times. In some instances, the active element  155  may be implanted into an eye  10  that already contains a passive lens (i.e., a non-accommodating IOL), thereby offering the possibility of presbyopia correction to a patient that cannot accommodate. 
     By providing unique and separable active and passive optical elements  155  and  160 , respectively, the accommodative IOL device  150  allows more options for customizing the combination of accommodative optical power and static optical power and for positioning the elements  155 ,  160  within the eye  10 . In addition, the accommodative IOL device  150  introduces the possibility of implanting only one element of the active and passive elements  155 ,  160 , respectively, into the eye  10 . For example, in an instance where the patient has presbyopia without cataracts, it may be preferable to implant only the active element  155  in front of (i.e., anterior to) a non-cataractous, presbyopic crystalline lens. 
     In some embodiments, in its expanded condition, the accommodative IOL device  150  comprises a substantially circular device configured to be self-stabilized within the eye  10  (e.g., within the lens capsule  18  or the sulcus  32 ). In some embodiments, in its expanded condition, the accommodative IOL device  150  comprises a substantially circular device having haptic supports  220 , as described below in relation to  FIG. 6 , configured to be self-stabilized within the eye  10  (e.g., within the lens capsule  18  or the sulcus  32 ). 
     The passive element  160  and/or the active element  155  may be shaped and configured to maintain the natural circular contour of the lens capsule  18  and to stabilize the lens capsule  18  in the presence of compromised zonular integrity when the accommodative IOL device  150  is positioned in the eye  10 . In some embodiments, the passive element  160  comprises a generally circular disc with a substantially circular shape configured to match the substantially circular cross-sectional shape of the lens capsule  18  when the lens capsule  18  is divided on a coronal plane through an equatorial region  23 . In some embodiments, the device  150  (i.e., the active element  155  and/or the passive element  160 ) may taper from the central region  165  of the device  150  towards a peripheral edge  170 . The peripheral edge  170  comprises the outermost circumferential region of the accommodative IOL device  150 . In some embodiments, the accommodative IOL device  150  may taper toward its peripheral edge  170  to facilitate stabilization of the accommodative IOL device  100  inside the lens capsule  18  and/or the eye sulcus  32 . This may allow the accommodative IOL device  150  to be self-stabilized and self-retained in the eye  10  (i.e., without the use of sutures, tacks, or a manually held instrument). In some embodiments, the angle of the taper from the central region  165  towards the peripheral edge  170  is selected to substantially match the angle of the equatorial region  23  in the lens capsule  18 , thereby facilitating self-stabilization of the accommodative IOL device  150  within the eye  10 . 
       FIG. 6  illustrates a perspective view of an exemplary accommodative IOL device  200  according to one embodiment of the present disclosure.  FIG. 7  illustrates a cross-sectional view of the exemplary accommodative IOL device  200  shown in  FIG. 6  implanted within the eye  10  according to one embodiment of the present disclosure. 
     The exemplary accommodative IOL device  200  shown in  FIGS. 6 and 7  is substantially the same as the accommodative IOL device  150  shown in  FIGS. 4A-5B  except for the differences mentioned below. Similar to the accommodative IOL device  150 , the accommodative IOL device  200  comprises a two-element IOL including an active component  205  and a passive component  210 . The active component  205  is substantially the same as the active element  155  described above. In the pictured embodiment shown in  FIG. 6 , the accommodative IOL device  200  comprises additional components  215  (e.g., power sources, circuitry, control modules, antennae, etc.) related to the operation of the electro-active element  155 . Several of the additional components  215  and the active element  205  are shown gathered together within a housing  218 . The passive component  210  is substantially the same as the passive component  160  described above. 
     In some instances, the two-element accommodative IOL device  200  (and the IOL device  150 ) can offer enhanced stability of the device and improved protection for the structures of the eye  10  in comparison to conventional IOL devices. For example, in some embodiments, as shown in  FIGS. 6 and 7 , the passive element  210  may act as an anchoring structure for the active element  205 . Moreover, if positioned behind or posterior to the active element  205 , the softer passive element  210  can act as a cushion during the implantation procedure of the active element  205  as well as during other procedures such as laser posterior capsulotomies. 
     In the pictured embodiment, the accommodative IOL device  200  comprises a substantially circular device including haptic supports  220 , as shown in  FIG. 6 , configured to be self-stabilized within the lens capsule  18  of the eye  10  (or the sulcus  32 ), as shown in  FIG. 7 . The haptic supports  220  comprise substantially pliable, curved, elongate members extending outwardly from the accommodative IOL device  200 . In the pictured embodiment, the haptic supports  220  extend radially from the passive element  210 . In other embodiments, the haptic supports  220  may extend from the active element  205 . The haptic supports  220  are shaped and configured to expand into the lens capsule  18  and/or the sulcus  32  to stabilize and anchor the IOL device  200  within the eye  10 . The haptic supports  220  may be shaped and configured to maintain the natural circular contour of the lens capsule  18  and to stabilize the lens capsule  18  in the presence of compromised zonular integrity when the accommodative IOL device  200  is positioned in the eye  10 . In the pictured embodiment, the IOL device  200  includes centralizing members  206  that are shaped and configured to stabilize and centralize the IOL device  200  within the lens capsule  18  of the eye  10  (or the sulcus  32 ). Other embodiments lack centralizing members  206 . 
     The accommodative IOL devices and systems described herein may be formed from any of a variety of biocompatible materials having the necessary optical properties to perform adequate vision correction as well as requisite properties of resilience, flexibility, expandability, and suitability for use in intraocular procedures. In some embodiments, the individual components of the accommodative IOL devices described herein may be formed of different biocompatible materials of varying degrees of pliancy. For example, in some embodiments, the passive region  110  and the passive elements  160  and  210  may be formed of a more flexible and pliant material than the active region  105  and the active elements  155  and  205  to minimize contact damage or trauma to intraocular structures. In other embodiments, the reverse relationship may exist. The accommodative IOL devices described herein may be coated with any of a variety of biocompatible materials, including, by way of non-limiting example, polytetrafluoroethylene (PTFE). 
     Persons of ordinary skill in the art will appreciate that the embodiments encompassed by the present disclosure are not limited to the particular exemplary embodiments described above. In that regard, although illustrative embodiments have been shown and described, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure. It is understood that such variations may be made to the foregoing without departing from the scope of the present disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the present disclosure.