Patent Publication Number: US-2022233304-A1

Title: Method of surgically implanting an intraocular lens (iol) using a capsular prosthesis to support posterior chamber fixation

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to US Pat. App. No. titled “A CAPSULAR PROSTHESIS FOR POSTERIOR CHAMBER INTRAOCULAR LENS (IOL) FIXATION,” and which is hereby incorporated herein in its entirety by this reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to intraocular lens (IOL) implantation, and more particularly to techniques for the surgical implantation of such lenses using a prosthesis in situations where capsular support is inadequate or non-existent. 
     BACKGROUND OF THE INVENTION 
     Cataract surgery is one of the most frequently and successfully performed surgeries performed on the human eye. The American Society of Cataracts and Refractive Surgery (ASCRS) estimates that 3 million Americans undergo cataract surgery each year, with an overall success rate of 98 percent or higher. A cataract is simply defined by clouding or discoloration of the crystalline lens that makes it difficult to focus light onto the retina  30 . When this occurs, a cataract surgeon removes the crystalline lens and replaces it with an artificial intraocular lens (i.e. IOL) that is able to properly focus light once again onto the retina ( 30 ,  FIG. 1A ) correctly. 
       FIG. 1A  is a simplified illustration of the anatomy of the human eye  10 . The crystalline lens  26  of the eye  10  has a nucleus  31  encased by a membranous bag-like structure called a capsule  24 , which is divided into the posterior  28  and anterior  34  capsules. The capsule  24  lies within the anterior segment  19  of the eye  10 , which is the front third of the eye  10  located in front of the vitreous humor  11 , and includes the cornea  14 , iris  12 , ciliary body  21 , and crystalline lens  26 . The crystalline lens  26  is generally located posterior to the iris  12 . The anterior chamber  16  is the space between the iris  12  and the cornea  14 . The crystalline lens  26  is suspended in place within the posterior chamber  17  by fine suspensory fibers called zonules  22  originating from the ciliary body  21 . 
     The crystalline lens  26  is generally aligned with the optical axis A-A′  55 . It extends through the geometric center of the cornea  16  to the geometric center of the retina  30 , approximately halfway between the optic nerve  31  and the fovea  32 . The optical axis A-A′  55  is defined by the geometric centers of cornea  16 , pupil  20 , and retina  30 . However, the visual axis B-B′  59  is the actual axis through which the human eye looks, which runs from a person&#39;s point of fixation to the fovea  32 . The angle α  58  between the optical A-A′  55  and visual  59  axes is about 5.2°. 
     A number of techniques are available to remove cataracts, and the one ultimately employed by the surgeon is dependent upon factors such as how advanced the cataracts are and the health of the patient&#39;s eyes generally. Phacoemulsification is the most commonly employed and desirable technique. The surgeon first tears a circular hole (i.e. capsulorhexis) (See  40 ,  FIG. 1B ) in the anterior capsule  34  to access the cataract. The crystalline lens  26  is loosened from the capsule  24  by injecting saline solution between the capsule  24  and the cataractous lens  26  material. The lens  26  material internal to the capsule  24  is liquified and aspirated from the eye using a phacoemulsification device (e.g. a metal cannula that vibrates at ultrasonic frequency). The device breaks up the cloudy cataract into tiny fragments that are removed from the eye  10  using suction. 
     As long as the capsule  24  remains largely intact other than the hole  40  (i.e. capsulorhexis) through which the affected crystalline lens  26  is removed, an IOL  70 ,  80  (such as the ones illustrated in  FIGS. 2A , B) is inserted through the incision and capsulorhexis  40  and is implanted within the capsular bag  24  in place of the removed crystalline lens  26 . Capsular placement or implantation is the optimal location anatomically for an IOL intended to replace the removed cataract. It provides optimal stability and permits the optic  72 ,  82  of the IOL to be located closest to the nodal point of the original nucleus  31  of the crystalline lens  26 , through which the optical axis A-A′  55  of the eye passes and which is substantially aligned with their centroid  76 ,  86 . 
     There are many types of intraocular lenses  70 ,  80  currently available, and are typically either a single-piece design  70 , or a three-piece design  80 . The choice of IOL is at least partially dictated by the therapeutic purpose to be served, as well as its suitability to the location within the eye where the IOL ultimately will be placed. IOL&#39;s all have an optic  72 ,  82  to focus the light on the retina  30  in lieu of the removed crystalline lens  26 , and arms (or haptics)  74 ,  84  that provide a reactive force to help hold and center the optic  72 ,  82  in a fixed position, with centroid  76 ,  86  substantially aligned with a desired axis of the eye (e.g. either the optical axis A-A′  55  or visual axis B-B′  59 ) at center  76 ,  86  as illustrated in  FIG. 1B . Centration of the optic  72 ,  82  is important to obtaining desired visual acuity. Most lenses have been designed with their centroid  76 ,  86  to be aligned with the center of the pupil  20  (and thus the optical axis A-A′  55 ) even though the visual axis  59  does not pass through this point. For spheric and aspheric lenses, this does not affect the visual acuity significantly. For newer lens technologies such as multifocal lenses, it may be more desirable to center the centroid  76 ,  86  of its optic  72 ,  82  with the visual axis B-B′  59  for optimal visual acuity. 
     Single piece IOL&#39;s  74 ,  FIG. 2A  are usually made entirely (both optic  72  and haptics  74 ) from hydrophobic or hydrophilic acrylic. As a result, single piece IOLs have haptics  74   a, b  that are soft and broad. They are often preferred for placement in reasonably intact capsules  28 ,  34 . Single-piece toric lenses are designed to correct for a patient&#39;s astigmatism. The optics  82  of three-piece IOLs  80 ,  FIG. 2B  are made from acrylic, silicone, or another suitable elastomer, and have haptics  84   a, b  that are made separately from the optic  82  and attached thereto. The haptics  84   a, b  are typically made of a different material such as polymethyl-methacrylate (PMMA) or polypropylene. Both are suitable for placement of an optic within the capsule as illustrated in  FIG. 1B . 
     For many reasons, the capsule  24  is not always left sufficiently intact to support implantation of the IOL  70 ,  80  within the capsule  24  as shown in  FIG. 1B . For example, a second surgical technique called extracapsular cataract surgery is sometimes employed in situations where the condition of the eye prevents the use of the more desirable phacoemulsification. One such situation is when the cataracts are more advanced, which renders them too dense for phacoemulsification. Extracapsular surgery requires a larger incision in the cornea  14 , which requires sutures for proper healing of that larger incision. In addition, it is not uncommon that during cataract surgery or long after, a number of complications can occur that can make it impossible to securely place an artificial IOL lens  70 ,  80  within the capsule. For example, the posterior capsule  28  can rupture during surgery such that a large hole (in addition to the surgically created capsulorhexis  40 ) in the capsular bag  24  precludes placing an IOL within it. 
     In cases where capsular placement of an IOL is not possible, a three-piece IOL  70  can be placed within the ciliary sulcus  18 .  FIG. 1C  illustrates such a placement. The haptics  84   a, b  can be seen located in the sulcus  18 , and the optic  82  is located anterior to the anterior capsule  34  and the capsulorhexis  40  made therein to remove the cataract. Unfortunately, for this type of placement, the long term centration of the optic  82  of the IOL  80  to the optical axis A-A′  55  can become compromised. Moreover, the haptics  84   a, b  can migrate and rub against the iris  12 , causing irritation thereto and depigmentation thereof. Patients often require a second procedure months or years after the first surgery to suture the lens  80  to the iris  12  or sclera  36  so that it does not fall into the posterior chamber (not shown), and to recenter the lens  80  to the optical axis A-A′  55  so that it properly focuses light onto the retina  30 . 
     If the anterior capsule  34  is reasonably intact, and the zonules  22  are able to still support the anterior capsule, an alternative technique for ciliary sulcus  18  placement (not pictured) can be used called reverse optic capture. In this technique, a three piece IOL ( 80 ,  FIG. 2B ) can be placed such that the haptics  84   a, b  are anterior to the anterior capsule  34 ,  FIG. 1C  and the optic  82  of the IOL  80  is then prolapsed posteriorly so that the optic  82  is forced through an intact capsulorhexis  40  in the anterior capsule  34  and is held in place thereby. Placement within the ciliary sulcus  18  via reverse optic capture is a more stable technique by which to achieve an IOL  80  with proper centration with respect to the optical axis A-A′  55  (as defined by the iris  12  and the pupillary border  44 ) notwithstanding a damaged posterior capsule  24 , than is the simpler sulcus placement of  FIG. 1C . 
     Another technique used for anterior segment  19  placement of an IOL  90  is to suture a three piece IOL to the iris  12 . Although a relatively good technique, it is technically difficult with a lengthy procedure that includes a steep learning curve. In addition to being difficult to perform, it is not unusual for the lens to chafe the iris  12 , causing inflammation or for the lens to dislocate. 
     In some situations, the entire capsule  24  complex (anterior  34  and posterior  28  capsule) is damaged and/or removed (see  FIG. 1D ), or the zonules  22  are damaged so extensively that ciliary sulcus  18  placement of the IOL  80 , with or without reverse optic capture simply cannot be performed. Thus, the next available mode of IOL ( 90 ,  FIG. 1D ) placement will typically be within the anterior chamber  16  of the eye  10 . Those of skill in the art will appreciate that  FIG. 1D  is intended to illustrate anterior IOL  90  placement in general, and not the fine details of any specific such anterior chamber lens design or technique. Currently, the most common way to address this complication is to make an even larger incision by which to place an anterior chamber lens (ACIOL) anterior to the iris  12 . While this technique is relatively simple, the large incision slows healing and the technique is more likely to cause failure of the cornea  14 , requiring corneal transplantation later in life. 
     In another known technique for anterior chamber  16  placement, an IOL  90  can be sutured directly to the white part of the eye (i.e. sclera  36 ). While this technique of anterior chamber placement does not damage the cornea  14 , it is often performed using a larger rigid lens which requires a commensurately larger incision. Because almost all lenses used for this technique have only two haptics, many of which are designed with varying angulation, only two effective points of contact exist between the IOL and the sclera  36 , making it easy for the surgeon to inadvertently place the lens  90  in a way that it will rotate and rub against the iris  12 . This can lead to iris chafe and inflammation within the eye. Finally, because many of the techniques discussed above require suturing the lens to the eye, it renders any efforts to replace those lenses a significant surgery in and of itself. 
     It would be desirable to avoid IOL placement after cataract surgery anterior to the capsule  24  in situations where the capsule  24  is not able to support placement therein, and particularly to avoid placements within the anterior chamber  16 . Placement within the capsule  24  is the natural position for lens placement and avoids the complications that can occur for placements within the anterior chamber  16 , and also within the sulcus  18 . It would also be desirable to minimize the invasiveness of procedures required to replace previously implanted lenses. It would be further desirable to facilitate a more uniform but flexible technique for lens replacement regardless of the type of IOL used, and to provide more freedom to achieve a desired centration of the optic. 
     SUMMARY OF THE INVENTION 
     A capsular prosthesis of the invention is disclosed that is configured to be implanted to support placement of IOLs in a position that substantially corresponds to the location of the naturally occurring crystalline lens provided by an intact capsule of the human eye prior to its removal. The capsular prosthesis can be implanted to essentially replace the capsule in situations where the patient&#39;s natural capsule has been rendered incapable of providing the structural support necessary to maintain proper centration of an IOL implanted therein. A method of implanting the prosthesis is further disclosed. 
     In one aspect of the invention, a method of surgically implanting an intraocular lens (IOL) into an eye using a capsular prosthesis to support posterior chamber fixation includes providing a capsular prosthesis comprising a sheet of substantially biocompatible and/or bioinert material. The sheet further includes an anterior and posterior face separated by a thickness, three or more vertices, each one of the vertices being uniquely associated with a suture aperture located proximally with its point, and a center aperture located centrally with the vertices and being dimensionally configured to permit supportive optical capture of the IOL without substantial impairment of optic functionality. 
     The prosthesis is surgically implanted into the eye by inserting the prosthesis into the eye through a primary incision. The prosthesis is secured to the sclera of the eye with at least two transscleral sutures to establish at least three points of contact between the sclera and the at least three apertures of the prosthesis. The at least two transscleral sutures to support the sheet within a desired plane located within the posterior chamber, the plane containing a predetermined surgical axis passing through the center aperture, the plane being approximately perpendicular to, and the center aperture of the sheet being functionally centered with, the predetermined axis of the eye. The IOL is inserted through a primary incision and optically captured on the prosthesis so that a center of the optic is approximately centered with the aperture and the predetermined axis of the eye. 
     In an embodiment, a first one of the at least two transscleral sutures is secured to a first set of one or more of the at least three suture apertures by looping the first transscleral suture through each of the first set of the suture apertures, and a second one of the at least two transscleral sutures is secured to a second set of one or more of the at least three suture apertures by looping the second transscleral suture through each of the second set of the suture apertures. 
     In an embodiment, the sheet of the prosthesis is substantially rectangular, and the first set of the suture apertures includes two of the suture apertures each located proximally with a different one of two vertices located at a first end of the sheet. The second set of the suture apertures includes two of the suture apertures each located proximally to a different of two vertices at a second end of the sheet. 
     In a further embodiment, the sheet of the prosthesis is substantially triangular in geometry, and the first set of the suture apertures includes an aperture located at the apex of the triangular sheet. The second set of the suture apertures includes two of the suture apertures each located proximally with a different one of the two vertices defining the base of the triangular sheet. 
     In a still further embodiment, each of the first and second looped transscleral sutures has two paired ends, and each one of the paired ends of the first looped transscleral suture are secured to the sclera of the eye through a sclerotomy made proximally with a first predetermined point along the predetermined surgical axis. Each one of the paired ends of the second looped transscleral suture are secured to the sclera of the eye through a sclerotomy made proximally with a second predetermined point located along the predetermined surgical axis and 180 degrees from the first predetermined point. 
     In a further embodiment, the first and second predetermined points are about 4 mm posterior to the surgical limbus of the eye. 
     In an embodiment, the sclerotomy points identified for each of the paired ends of the first and second transscleral sutures are on opposite sides of the predetermined surgical axis approximately 3 mm from the first and second predetermined points respectively. 
     In an embodiment, the sclerotomy for each of the paired ends of the first and second looped transscleral sutures is made on opposite sides of the predetermined surgical axis, approximately 3 mm from the first and second predetermined points respectively. 
     In another embodiment, the primary incision is made at a first predetermined incision point along the predetermined surgical axis. 
     In a still further embodiment, the primary incision is made at a first incision point along an axis that is approximately perpendicular to the predetermined surgical axis. 
     In another aspect of the invention, the first and second looped transscleral sutures are loaded through the first and second sets of apertures respectively prior to surgery, each of the paired ends being coupled to a surgical needle. 
     In an embodiment, securing the prosthesis to the sclera further includes, for each of the paired ends of the first transscleral suture, making a sclerotomy from outside of the eye substantially at the identified sclerotomy point using a hollow needle until a proximal end of the hollow needle becomes visible behind the pupil of the eye, inserting the surgical needle into the eye through the primary incision. The inserted needle is docked into the proximal end of the hollow needle and loaded the inserted needle until the inserted needle emerges outside of a distal end of the hollow needle remaining outside of the eye. 
     In an embodiment, securing the prosthesis to the sclera further includes, for each of the paired ends of the second transscleral suture, making a sclerotomy from outside of the eye substantially at the identified sclerotomy point using a hollow needle until a proximal end of the hollow needle becomes visible behind the pupil of the eye, inserting the surgical needle into the eye through the primary incision. The inserted needle is docked into the proximal end of the hollow needle and loaded the inserted needle until the inserted needle emerges outside of a distal end of the hollow needle remaining outside of the eye. 
     In another embodiment, the sclerotomy points that are identified for each of the paired ends of the first and second transscleral sutures are on opposite sides of the predetermined surgical axis approximately 3 mm from the first and second predetermined points respectively. 
     In yet another embodiment, the primary incision is made at a first predetermined incision point along the predetermined surgical axis. 
     In a further embodiment, the primary incision is made at a first incision point along an axis that is approximately perpendicular to the predetermined surgical axis. 
     In another embodiment, the first and second looped transscleral sutures are loaded through the first and second sets of apertures respectively prior to surgery, each of the paired ends being coupled to a surgical needle. 
     In a further embodiment, securing the prosthesis to the sclera further includes: for each of the paired ends of the first transscleral suture, making a sclerotomy from outside of the eye substantially at the identified sclerotomy point using a hollow needle until a proximal end of the hollow needle becomes visible behind the pupil of the eye, inserting the surgical needle into the eye through the primary incision; and docking the inserted needle into the proximal end of the hollow needle and loading the inserted needle until the inserted needle emerges outside of a distal end of the hollow needle remaining outside of the eye. 
     In still another embodiment, said securing the prosthesis to the sclera further includes: for each of the paired ends of the second transscleral suture, making a sclerotomy from outside of the eye substantially at the identified sclerotomy point using a hollow needle until a proximal end of the hollow needle becomes visible behind the pupil of the eye, inserting the surgical needle of the paired end into the eye through the primary incision; and docking the inserted needle into the proximal end of the hollow needle and loading the inserted needle until the inserted needle emerges outside of a distal end of the hollow needle remaining outside of the eye. 
     In another embodiment, after removing the needles from the paired ends, both paired ends of the first suture are pulled to pull the prosthesis within the eye through the primary incision. 
     In another embodiment, the paired ends of both sutures are pulled to suspend the prosthesis within the eye and so that it approximately occupies the desired plane. 
     In another embodiment, the IOL is pulled into the eye through the primary incision using a standard lens insertion cartridge. 
     In a still further embodiment, the optic is manipulated with a surgical instrument so that its longitudinal edges are in contact with one of the faces of the prosthesis, so that the optic is substantially centered with the center aperture of the prosthesis, and the haptics of the IOL are captured within vertex features defined by the center aperture to resist further displacement. 
     In yet another embodiment, the predetermined surgical axis is determined to match the axis of astigmatism of the eye to facilitate easier placement of the IOL, and the IOL is a single-piece toric lens. 
     In another embodiment, securing the prosthesis to the sclera includes subjecting each of the paired ends of the first and second looped transscleral sutures to heat cautery to make thickened flanges to secure the looped transscleral sutures within the sclera of the eye. 
     In an embodiment, securing the prosthesis to the sclera further includes tying the paired ends of the first and second looped transscleral sutures to secure the looped transscleral sutures within the sclera of the eye. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a simplified cross-sectional side view illustration of the anatomy of the human eye; 
         FIG. 1B  is a simplified cross-sectional side view illustration of a human eye from which a cataract has been surgically removed and replaced with an intraocular lens (IOL) that has been implanted in the capsule using techniques known to those of skill in the art; 
         FIG. 1C  is an image of a human eye from which a cataract has been surgically removed and replaced with an intraocular lens (IOL) placed in the sulcus in accordance with techniques known to those of skill in the art; 
         FIG. 1D  is a simplified cross-sectional side view illustration of a human eye from which a cataract has been surgically removed and replaced with an intraocular lens (IOL) that has been surgically implanted into the anterior chamber in accordance with techniques known to those of skill in the art; 
         FIG. 2A  is a plan view of a single piece IOL known to those of skill in the art; 
         FIG. 2B  is a plan and side view of a three-piece IOL known to those of skill in the art; 
         FIG. 3A  is a plan view of a rectangular embodiment of a capsular prosthesis; 
         FIG. 3B  is a side view of the embodiment of the capsular prosthesis of  FIG. 3A ; 
         FIG. 4A  is an elevated anterior view of the embodiment of the prosthesis of  FIGS. 3A  and B with a three-piece IOL reverse optically captured thereon; 
         FIG. 4B  is a side view of the embodiment of the prosthesis of  FIGS. 3A , B and  FIG. 4A  with a three-piece IOL reverse optically captured thereon; 
         FIG. 5  is a plan view of a triangular embodiment of the capsular prosthesis; 
         FIG. 6A  is a is an elevated anterior view of the embodiment of  FIG. 5  with a one-piece IOL optically captured thereon; 
         FIG. 6B  is a is an elevated posterior view of the embodiment of  FIGS. 5 and 6A  with a one-piece IOL optically captured thereon; 
         FIG. 7  is a plan view of a human eye within which the embodiment of the prosthesis of  FIGS. 3A , B and  4 A, B (or alternatively the embodiment of  FIGS. 5A, 6A, and 6B ) has been surgically implanted through an embodiment of method of surgical implantation of the invention; 
         FIGS. 8A-H  each illustrate, through a plan view of the human eye, one of a series of surgical stages of a method of surgical implantation of the invention by which an embodiment of the prosthesis is surgically implanted to achieve the result illustrated in  FIG. 7 ; 
         FIG. 9A  is a plan view of a rectangular embodiment of the capsular prosthetic, having been surgically implanted within the eye in accordance with the surgical implantation procedure of  FIGS. 8A-H , supporting a one piece IOL through optic capture; 
         FIG. 9B  is a plan view of a triangular embodiment of the capsular prosthetic, having been surgically implanted within the eye in accordance with the surgical implantation procedure of  FIGS. 8A-H , supporting a three piece IOL through reverse optic capture; 
         FIGS. 10A-D  illustrate surgical steps that may be substituted for steps illustrated in  FIGS. 8A-H  for an alternate method of the invention for implanting the prosthesis; 
         FIG. 11A  is a diagnostically produced visual representation of a patient&#39;s axis of astigmatism; 
         FIG. 11B  is a plan view of an adjusted surgical placement of the embodiment of the prosthesis of the invention of  FIGS. 3A , B and  4 A, B having a one-piece toric IOL optically captured thereon, to compensate for the angle of astigmatism of  FIG. 11A ; and 
         FIG. 12  is an illustration of the triangular prothesis of  FIG. 9B  having one transscleral suture per suture aperture. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of methods for surgically implanting a capsular prosthesis are disclosed. The prosthesis is implanted in accordance with methods of the invention to receive and support commercially available single and three-piece IOL&#39;s  70 ,  80  ( FIGS. 2A, 2B ) via their haptics  74 ,  84  ( FIGS. 2A, 2B ) by way of a prosthetic optic capture to secure the lens  70 ,  80  ( FIGS. 2A, 2B ) to the prosthesis and to hold accurate centration with the center  76 ,  86  of its optic  72 ,  82  ( FIGS. 2A, 2B ) with a desired axis of the eye thereby. This eliminates the need to suture the haptics  74 ,  84  ( FIGS. 2A, 2B ) themselves to either the sclera  36 ,  FIG. 1A  or the iris  12 ,  FIG. 1A  as is often required of anterior chamber  16 ,  FIG. 1D  and some sulcus  18 ,  FIG. 1C  placement techniques in lieu of capsular implantation ( FIG. 1D ) when it is not practicable. Moreover, the surgical methods of implanting the prosthesis  100 ,  200  of the invention serve to normalize placement of the various lens designs with their haptics independent of varying materials, lengths, and degrees of angulation. The methods of surgical implantation of prosthesis  100 ,  200  simplify placement of the lens optic  72 ,  82  planar to the iris  12  and with substantially optimal centration to a desired axis of the eye  50 , such as optical axis A-A′  55  or visual axis  59 , regardless of the design or composition of the IOL used. 
     The methods of implantation and features of prosthesis  100 ,  200  provide a plurality of points of contact greater in number than just the two typically provided by the haptics of an IOL alone. This renders the IOL largely immune from torquing after implantation, as well as eliminating the need for post-operative adjustments of the IOL to achieve optimal centration with the eye&#39;s optical A-A′  55  or visual  59  axis. These points of contact are made by way of at least two looped sutures, one proximal and one distal to the surgeon, which are looped through prosthesis  100 ,  200  and introduced through the sclera  36 . These points are predetermined by the surgeon to achieve a desired surgical axis C-C′ ( 60 ,  FIGS. 5A, 6A, 8 ) for placement of the prosthesis that defines a plane that is perpendicular to the desired axis to which the IOL  70 ,  80  is to be centered. Centration can be achieved by pulling on the paired ends of each of the two sutures before they are surgically fixed within the sclera  36  (e.g. tying them into knots, subjecting each of the paired ends to heat cautery, etc.). This serves to suspend the flexible but resilient prosthesis like a trampoline to support the IOL thereon. 
     Through the methods of implantation of the invention, the capsular prosthesis  100 ,  200  is surgically secured within the posterior chamber  17  (in the space normally occupied by the anterior capsule  34 ). As a result, the prosthesis of the invention ( 100 ,  200  of  FIGS. 3A, 3B, 4A, 4B, 5, and 6A , B) has been configured to support a three-piece IOL having been secured thereon using reverse optic capture, or a single piece IOL via optic capture. This enables standard IOLs to be placed in substantially the same concentric alignment as that previously provided by the patient&#39;s pre-operative capsule for the removed cataract. Surgical implantation of the capsular prosthesis thereby eliminates the need for virtually all of the less than ideal placement techniques of IOLs in the ciliary sulcus  18  or the anterior chamber  16 , and particularly in situations where the capsule  24  is not sufficiently sound to support capsular implant of an IOL  70 ,  80  within the naturally occurring capsule  24 . 
     The prosthesis  100 ,  200  of the invention essentially replicates sulcus  18  placement of three-piece IOLs  80  with reverse optic capture, in that the center aperture  106 ,  206  of prosthesis  100 ,  200  of the invention acts in lieu of an intact capsulorhexis  40  of an anterior capsule when using reverse optic capture for a sulcus placement of an IOL. It can also be used to accomplish optic capture of one-piece IOLs  80  by capturing the optic  82  on the anterior side of the prosthesis and prolapsing the haptics to the posterior side of the prosthesis. The haptics  84  are placed though the center aperture  106  and forward of the anterior capsule  34 , and the optic  82  of the three-piece lens  80  is captured against the prosthesis similar to the manner in which it is captured if it were prolapsed through the capsulorhexis of the anterior capsule  34 . Alternatively, if a one-piece IOL  70  is used that cannot safely be placed in a reverse optic capture orientation, the haptics  74  can be prolapsed posterior to the prosthesis  100 ,  200  with the optic  72  being placed anterior to the prosthesis  100 ,  200 . 
     Existing methods of lens placement and fixation, particularly within the anterior chamber  16 , involve fixating the IOL to structures in the eye  50  itself using sutures. Thus, when replacing that IOL when indicated by, for example, a poor refractive outcome, such replacement becomes a major surgical procedure to remove the sutures of the IOL to be replaced, and then suturing in a new one. The prosthesis  100 ,  200  of the invention facilitates easy lens replacement through a small incision, because the implanted prosthesis  100 ,  200  itself does not have to be removed to replace the IOL. Replacement simply requires that the existing IOL supported by the prosthetic be removed and replaced with a new lens being supported by the previously implanted prosthetic. Thus, easy fixation of various commercially available IOL designs to the prosthesis  100 ,  200  of the invention renders IOL removal and replacement simple and less invasive. 
     Easy removal also facilitates the use of advanced technology IOLs, like multifocal and trifocal lenses. While these lenses provide a greater range of focus, they are also less forgiving of decentration or retinal issues. Likewise, the ability to rotate the surgical axis  60  in performing the methods of surgical implantation of the invention also permits easier centration of the IOLs with the desired axis of the eye (e.g. the optical axis  55 , visual axis  59 , or possibly another axis). For example, a multifocal IOL, fixated within the prosthesis of the present invention rather than directly to the iris  12  or sclera  36 , can be easily replaced with a mono-focal IOL without causing extensive damage to the supporting structures of the eye  10 . Those of skill in the art will appreciate that the methods of surgical implantation of the prosthesis  100 ,  200  of the invention is not limited to lens replacement necessitated by the surgical removal of cataracts. As is illustrated in  FIGS. 10A  and B, a desired surgical axis  1510  can be established that matches the axis of astigmatism  900  of an eye  800  to facilitate easier placement of single-piece toric lenses  872  as well. 
       FIGS. 3A , B illustrate an embodiment  100  of the capsular prosthesis of the invention. In an embodiment, the prosthesis  100  is a thin rectangular sheet  108  of preferably low bio reactive or bioinert, flexible (yet resilient) material having two planar faces  107  that are substantially identical. The sheet has two sets  102   a, b  and  103   a, b  of suture apertures through the sheet  108  proximal to its corners or vertices. The sheet  108  has an aperture  106  substantially centered within that is large enough to provide an optical line of sight along optical axis A-A′  55  for the optics of most commercially available intraocular lenses (IOLs). Center aperture  106  has a centroid  150 , that itself can also be the centroid of the sheet  108 . Center aperture  106  further includes vertex features  104   a, b  suitable for capturing haptics of the IOLs passed therethrough to resist them from sliding once captured therein. 
     In an embodiment, sheet  108  can have a length  110   a  of approximately 11 mm, a width  110   b  of approximately 7 mm, and a thickness  110   c  that can be approximately 0.25 mm. In an embodiment, center aperture  106  can have an internal length of about 8 mm between vertex features  104 , and an internal width of about 5 mm. The diameter of suture apertures  102   a, b  and  103   a, b  can be about 1.5 mm. Those of skill in the art will recognized that these dimensions may be varied to fit a range of commercially available lenses, sutures, and needles. The thickness  110   c  of the sheet  108  will vary depending upon the material from which the sheet is made. The sheet can be made of substantially bioinert materials including but not limited to, silicone, polyimide, acrylic or the like. The sheet  108  should be flexible enough that it is foldable, so that it can be made small enough to be inserted into the eye through a primary clear corneal incision of about 2-3 mm. It should also be sufficiently resilient to re-establish its full original dimensions for proper deployment once inserted into the eye. Those of skill in the art will appreciate that the height of sheet  108  will be dictated by the anatomy of the eye. Sheet  108  should be operable to capture and support optic  72 ,  82  of lens  70 ,  80 , by substantially aligning centroid  76 ,  86  of optic  72 ,  82  with centroid  105  of central aperture  106 . By substantially aligning center aperture centroid  150  with optical axis A-A′  55  or visual axis B-B′  59  during implantation, centroid  76 ,  86  of IOL should also be substantially so aligned. The sheet  108  does not have to be particularly rigid because it is sutured to be supported at its four vertices, which allows it to be suspended like a trampoline and is therefore maintained at its fully deployed geometry to provide sufficient supportive rigidity within the appropriate plane. 
       FIGS. 4A , B illustrate a view of what is defined as the anterior surface  107   a  of the prosthesis  100  from the perspective of a surgeon. The three-piece IOL  80 ,  FIG. 2B  mounted on the prosthesis  100  having optic  82  and haptics  84   a, b.  The IOL  80  is mounted in a reverse optic capture configuration, with its haptics  84   a, b  placed forwardly through aperture  106  from the posterior side and captured within vertex features  104   a, b  respectively on the anterior surface  107   a.  Optic  82  is substantially centered behind center aperture  106  on what is the posterior surface  107   p  from the perspective of a surgeon and has optical line of sight along axis A-A′  55 .  FIG. 4A  shows a surgical axis C-C′  60  aligned with the optical axis A-A′  55 . 
       FIG. 4B  shows a side view of the reverse captured IOL  80 , whereby the optic  82  has been prolapsed through the aperture  106  such that haptics  84   a, b  exert a force on the anterior surface  107   a  that pulls the optic  82  against the posterior surface  107   p  of the sheet  108 . This works much the same way as does a sulcus placement of such a lens using reverse optic capture, wherein the optic  82  is prolapsed into the capsulorhexis  40  into the anterior capsule  34 , the haptics  84   a, b  disposed in the sulcus  18  and pulling the optic  82  against the inside surface of the anterior capsule  34  defining the capsulorhexis  40 . 
       FIG. 5  illustrates an alternate embodiment  200  of the prosthesis of the invention that is triangular in geometry rather than rectangular. This triangular embodiment  200  has three, rather than four, suture apertures  202 ,  203   a  and  203   b  each located proximally to one of the three vertices of the triangular sheet  208 . The three vertices  202 ,  203   a  and  203   b  are rounded off to avoid creating sharp points that could irritate or potentially damage structures in the eye during implantation. The thin rectangular sheet  208  is also made of a bioinert, flexible (yet resilient) material having two planar faces  207  that are substantially identical. The triangular sheet  208  has an aperture  206  substantially centered within that is large enough to provide an optical line of sight along a desired axis of the eye  50 , (e.g. optical axis A-A′  55  or visual axis B-B′  59  for the optics of most commercially available intraocular lenses (IOLs). Center aperture  206  has a centroid  250  that itself can also be the centroid of the sheet  208 , and further includes vertex features  204   a, b  suitable for capturing haptics of the IOLs passed therethrough to resist them from sliding once captured therein. In an embodiment, the dimensions of the triangular sheet  208  can be scaled as necessary to accommodate the inside dimensions of the center aperture  206 . 
       FIG. 6A  illustrates a view of what is defined as the anterior surface  207   a  of the prosthesis  200  from the perspective of a surgeon. A one-piece IOL  70 ,  FIG. 2A  is mounted on the prosthesis  200  having optic  72  and haptics  74   a, b.  The IOL  70  is shown mounted on prosthesis  200  using an optic capture, where its haptics  72   a, b  are placed rearwardly through aperture  206  and emerging from the aperture  206  and captured within vertex features  204   a, b  respectively on the posterior side and surface  207   p.  The centroid  76  of optic  72  is substantially centered with the centroid  250  of aperture  206  on what is the anterior surface  107   a  from what will be the perspective of a surgeon performing implantation of the centroid  76  of optic  72  is substantially centered with optical axis A-A′  55  of an eye  50 . Those of skill in the art will appreciate that centration of the optic  72  and centroid  250  can be made with respect to any desired axis, including the visual axis B-B′  59 .  FIG. 6B  shows a posterior view of the captured IOL  70 , whereby the haptics  74   a, b  have been prolapsed through the aperture  206  from the anterior side such that haptics  74   a, b  exert a force on the posterior side surface  207   p  that pulls the optic  72  against the anterior surface  107   a  of the sheet  208  and maintains its position. 
       FIG. 7  illustrates prosthesis  100  and a reverse optically captured three-piece IOL having optic  82  and haptics  84   a, b  mounted thereon, having been implanted in the posterior chamber  18  of eye  500  within the space that was once the approximate location of the anterior capsule  34  in accordance with an embodiment of surgical methods of the invention. Two looped transscleral sutures  616   p  (i.e. posterior) and  616   d  (i.e. distal) are shown each a pair of ends, which are passed through sclera  36  at sclerotomies  652   a, b  and  650   a, b  respectively, and looped through the suture apertures  103   a, b  and  102   a, b  of prosthesis  100  respectively. Each pair of ends of the looped sutures  616   p, d  respectively is ultimately surgically secured to the sclera  36  at paired sclerotomy points  652   a, b  and  650   a, b  (at the bottom and top the eye  500  respectively). Sutures  616   d, p  should be of a thickness, strength and durability sufficient to hold an IOL in place permanently (e.g. a 9-0 or larger prolene, or Gore-Tex suture). 
       FIGS. 8A-J  illustrate surgical steps of one embodiment of a method of surgical implantation of the prosthetic  100 ,  200 . These steps are now described with reference to those illustrations. Prior to beginning surgery, the surgeon will assure that the eye  500  is of appropriate pressure using either viscoelastic solution or infusion. 
     In an embodiment, distal suture  616   d  is initially established as a double armed suture (needles coupled to both ends of a loop of suture) with long needles  420   a,    420   b  (e.g. CTC-type needles) as illustrated in  FIG. 8A . Distal suture  616   d  is coupled to one end (which becomes the distal end) of the prosthesis  100 , by pulling one needle  420   a  through one suture aperture  102   a  of prosthesis  100  and the second needle  420   b  through the second suture aperture hole  102   b  so that a loop of suture is slidably secured to the distal end of the sheet  108  of prosthesis  100 . If embodiment  200  of prosthesis  100  is used, this distal suture  616   d  can be looped through single aperture  200  or through apertures  203   a, b,  depending upon the desired orientation of the prosthesis  200 . A loose loop of suture  514  is also established through the lens aperture  106 ,  206  at the proximal end of the prosthesis  100 ,  200 . Loop  514  is of sufficient length to serve as a safety suture to prevent the prosthesis  100 ,  200  of the invention from falling into the vitreous of the eye  500  like a trap door during the surgery. 
     As illustrated in  FIG. 8B , a primary clear corneal incision  618  of about 3 mm is made along the predetermined surgical axis C-C′  60  falling in the plane in which the IOL  70 ,  80  is to be placed. A secondary clear corneal incision  620  of about 1 mm is made substantially 180 degrees from the primary incision and along predetermined surgical axis C-C′  60 . The plane in which the predetermined surgical axis C-C′  60  lies also intersects both optical axis A-A′  55  and visual axis B-B′  59 . Those of skill in the art will appreciate that the primary  618  and/or secondary  620  clear corneal incisions could be made in the sclera  36  instead of the cornea  14  if preferable. 
     A distal mark  508   d  is first determined and then made on the surface of sclera  36  by measuring along the surgical axis C-C′  60  extending above the center of the pupil  20  to a point on sclera  36  about 4 mm posterior to the surgical limbus  542  of the eye  500 , and which is also just posterior (with respect to the pupil  20 ) to the secondary clear corneal incision  620 . Distal sclerotomy points  550   a,    550   b  are marked on the sclera  36  to form two ends of a line segment of about 6 mm in length, running through second measured mark  508   d  and running substantially perpendicular to the predetermined surgical axis C-C′  60  such that predetermined surgical axis C-C′  60  bisects the line segment that connects the two sclerotomy points  550   a,    5520 . The surgical limbus  542  of the eye  500  forms the border between the transparent cornea and opaque sclera  36 , contains the pathways of aqueous humor outflow, and is the site of surgical incisions for cataract and glaucoma (hence being referred to as the surgical limbus). 
     A proximal mark  508   p  is then first determined and then made on the surface of the sclera  36  by measuring along the surgical axis C-C′  60  extending below the center of the pupil  20  a point on sclera  36  about 4 mm posterior to the surgical limbus  542  of the eye  500 , and which is just posterior (with respect to the pupil  20 ) to the primary clear corneal incision  618 . Proximal sclerotomy points  552   a,    552   b  are marked on the sclera  36  to form two ends of a line segment of about 6 mm in length, running through second measured mark  508   p  and running substantially perpendicular to the predetermined surgical axis C-C′  60  such that predetermined surgical axis C-C′  60  bisects the line segment that connects the two sclerotomy points  552   a,    552   b.    
     As illustrated in  FIG. 8B , a 27 gauge or similar hollow hypodermic or sclerotomy needle  510  can be used to make a sclerotomy at a first  550   a  of the two marks until the needle  510  becomes visible behind the pupil  20  of the eye  500 . Using one end of the preloaded double armed suture  616   d,  the CTC needle  420   a  is inserted through the primary incision  618  into the eye  500  and docked into the sclerotomy needle  510 . Loading of the CTC needle  420   a  continues until its tip is well outside the eye  500  as shown. The needle  510  is then removed the CTC needle  420   a  is pulled until that first paired end of the suture  616   d  is entirely through the sclera  36 . Needle  420   a  is also removed from the first paired end of suture  616   d  as is shown in  FIG. 8C . 
     The foregoing steps are then repeated for the second sclerotomy mark  550   b  as illustrated in  FIG. 8C . The hollow hypodermic needle  510  can be used to make a sclerotomy at the second  550   b  of the two sclerotomy marks until the needle  510  becomes visible behind the pupil  20  of the eye  500 . Using the second paired end of the preloaded double armed suture  616   d,  the second CTC needle  420   b  is inserted through the primary incision  618  and into the eye  500  and is docked it into the sclerotomy needle  510 . The CTC needle  420   b  is then loaded until its tip is well outside the eye  500  as described above. Hollow needle  510  is then removed and the CTC needle  420   b  is pulled through until the second paired end of the suture  616   d  is entirely through the sclera  36 . Needle  420   b  is also removed from the first end of suture  616   d  as shown in  FIG. 8D . 
     As is also illustrated in  FIG. 8D , both ends of the looped transscleral suture  616   d  have been pulled, thereby having caused the prosthesis  100  of the invention to be drawn into the eye  500  through the primary incision  618 . Those of skill in the art will appreciate that the drawings herein are not to scale, and that the width  110   b  of the sheet  108  could be over twice the length of the 2-3 mm primary incision  618 . As previously discussed, the sheet  108  will be sufficiently flexible such that it easily could be folded in half and held in that mode to facilitate insertion through the primary incision  618  before releasing it to re-establish its full form. Those of skill in the art will further appreciate that the loop suture  514  provides a means by which to maintain sheet  108  of the prosthesis  100  in a substantially planar orientation with respect to the surgical axis C-C′  60 . Loop  514  remains at least partially outside of the eye  500  through the primary incision  618  and serves to prevent the prosthesis  100  from falling into the vitreous. It also serves to provide a handle by which to hold the sheet planar while cannulating surgical needles  420   c, d  through the proximal suture apertures  103   a, b  as described below. 
     As illustrated in  FIG. 8E , a second double armed suture  616   p  has been established (preferably but not necessarily when the first double armed suture  616   d  was established) having CTC needles  420   c  and  420   d  attached at the first and second ends thereof. The hollow hypodermic needle  510  can then be used to make a sclerotomy at mark  552   a  until the needle  510  becomes visible behind the pupil  20  of the eye  500 . Using the first end of the second preloaded double armed suture  616   p,  the CTC needle  420   c  is inserted through the secondary incision  620  and into the eye  500  and is first cannulated through suture aperture  103   a  and then docked into the sclerotomy needle  510  as shown. The CTC needle  420   c  is loaded until its tip is well outside the eye  500  as previously discussed. The needle  510  is removed, and the CTC needle  420   c  is pulled until that first paired end of the suture  616   p  is entirely through the sclera  36 . Needle  420   c  is also removed from the first end of suture  616   d  as is shown in  FIG. 8F . 
     And as is further illustrated in  FIG. 8E , the hollow hypodermic needle  510  can be used to make a sclerotomy at mark  552   b  until the needle  510  becomes visible behind the pupil  20  of the eye  500 . The second paired end of the second preloaded double armed suture  616   p  coupled to CTC needle  420   d  is inserted through the secondary incision  620  and into the eye  500  and is first cannulated through suture aperture  103   b  and then docked it into the sclerotomy needle  510  as illustrated. The CTC needle  420   d  is loaded until its tip is well outside the eye  500  as previously discussed above. The hollow needle  510  is removed, and the CTC needle  420   d  is pulled until that end of the suture  616   p  is entirely through the sclera  36 . Needle  420   c  has also removed from the first end of suture  616   d.  The result is shown in  FIG. 8G . 
     The loop suture  514  can now be removed from the center aperture  106  of the prosthesis  100  and both of the paired ends of the proximal transscleral suture  616   p  are pulled to suspend the prosthesis  100  within the eye  500  as is illustrated in  FIG. 8H . Both ends of the distal  616   d  and proximal  616   p  looped sutures can be pulled simultaneously to adjust the position of the prosthesis  100  along the surgical axis  55  C-C′  60  as needed to substantially center the centroid  150  of center aperture  106  of the prosthesis  100  to the optical axis A-A′  55  (approximately the center of the pupil  20 ) of the eye  500 . This result is illustrated by  FIG. 8H . 
     As illustrated in  FIG. 9A , with the prosthesis  100  centered so that the , the paired ends of each of the transscleral looped sutures  616   d,    616   p  can then either be tied, or subjected to heat cautery to make thickened flanges, to secure the sutures within the sclera  36 . With the prosthesis  100  now securely centered within the eye  500 , a one or three piece intraocular lens  70 ,  80  can be inserted into the eye through primary incision  618  using a standard lens insertion cartridge (not shown) known to those of skill in the art.  FIG. 9  illustrates a three-piece IOL  80  that has been mounted to prosthesis  100  by way of reverse optic capture. A Sinskey hook or other instrument can be used as known in the art to manipulate the optic  82  so that its longitudinal edges are posterior to the prosthesis  100  and in contact with a posterior facing surface ( 107   b  not shown) of the sheet  108  of the prosthesis  100 , leaving the haptics  84   a, b  anterior to the prosthesis  100  and captured within the vertex features  104  on the anterior face  107   a.  The position of optic  82  is then adjusted until the optic centroid  85 , the central aperture centroid  150  and the optical axis A-A′  55  are substantially aligned. 
     In  FIG. 9B , surgical implantation of embodiment  200  of the prosthesis is illustrated. The only difference in the surgical process presented above is that because embodiment  200  is triangular, one of the transscleral sutures is looped through the single suture aperture  202 . In addition, alignment is made to the visual axis B-B′  59 . The single aperture  202  can be at the distal end of the prosthesis, or it can be rotated 180 degrees so that it is located at the proximal end.  FIG. 9B  illustrates a single-piece IOL  70  that has been mounted to prosthesis  100  by way of optic capture. Thus, a Sinskey hook or other instrument can be used as known in the art to manipulate the optic  72  so that its longitudinal edges are anterior to the prosthesis  200  and in contact with an anterior facing surface  107   a  of the sheet  208  of the prosthesis  200 , leaving the haptics  74   a, b  posterior to the prosthesis  100  and captured within the vertex features  104  on the posterior face  107   b  (not shown). The position of optic  72  is then adjusted until the optic centroid  76 , the central aperture centroid  250  and the visual axis B-B′  59  are substantially aligned. Those of skill in the art will appreciate that each embodiment of the prosthesis  100 ,  200  is capable of supporting either type of IOL  70 ,  80 . 
     As illustrated in  FIG. 7 , the plane to be occupied by the prothesis  100 ,  200  contains the desired surgical axis C-C′  60  and is shown to be substantially perpendicular to the optical axis A-A′  55 . Transscleral Sutures  616   d,    616   p  defined by the proximate  552   a, b  and distal  550   a, b  pairs of sclerotomy points are located anterior to the ciliary bodies  21 . This of course defines the relative position of the optic  72 ,  82  along the optical axis A-A′  55 . Those of skill in the art will recognize that other locations for the sclerotomy points can range to just posterior to the ciliary bodies  21  at the anterior pars plana), resulting in different positions of the optic  70 ,  80  along the optical axis A-A′  55  may be also desirable. 
     Moreover, those of skill in the in art will appreciate the desired surgical axis C-C′  60  forms a substantially perpendicular bisector of each pair of sclerotomies  652   a, b  and  650   a, b,  and are therefore approximately 180 degrees apart from one another along the desired surgical axis C-C′  60 . These points can be rotated over 180 degrees before returning to the functionally equivalent original (albeit inverted) orientation as shown in  FIG. 7 . The resulting rotation around the optical axis A-A′  55  does not affect centration of spherical lenses, but this can be useful with regard to the fixation of non-spherical lenses such as toric lenses, the rotational orientation of which is critical for correcting a person&#39;s astigmatism. This will be discussed in more detail below. 
     Those of skill in the art will also appreciate that the establishment of sclerotomy fixation points for the prosthesis can also be rotated forward to center the IOL&#39;s on the visual axis if desirable. The embodiment of the surgical method described above establishes the surgical axis C-C′  60  to be substantially perpendicular to the optical axis A-A′  55 . This is the easier axis to which surgeons can achieve centration because it substantially aligns with the center of the pupil  20 . But in the event that centration of the IOL  70 ,  80  with visual axis visual axis B-B′  59  is desirable, the surgical methods and the prosthesis  100 ,  200  of the invention can easily accommodate rotating the plane in which the prosthesis  100 ,  200  lies to be made more perpendicular to the visual axis B-B′  59  by rotating the surgical axis C-C′  60  forward by an angle substantially equal to the angle α  58  shown in  FIG. 7 . 
     An alternative embodiment of the surgical method discussed above can eliminate the need to cannulate the second transscleral suture  616   p  within the eye  500 , and further eliminates the need for secondary incision  620 . In this embodiment, both transscleral double armed sutures  616   a, b  can be looped through the suture apertures of prosthesis  100 ,  200  outside of the eye, as illustrated in  FIG. 10A . The predetermined surgical axis C-C′  60  has been rotated counterclockwise 90 degrees and is still perpendicular to the optical axis A-A′  55 . In this surgical method, the primary incision  618  is bisected by an axis of incision  61  that is substantially perpendicular (i.e. at 90°) to the predetermined surgical axis C-C′  60 . 
     A first surgical mark  508   a  is determined and then made on the surface of sclera  36  by measuring along the surgical axis C-C′  60  extending left of the center of the pupil  20  to a point on sclera  36  about 4 mm posterior to the surgical limbus  542  of the eye  500 , and which is also just posterior (with respect to the pupil  20 ) to a radius including the secondary clear corneal incision  620 . A first pair of sclerotomy points  550   a,    550   b  are marked on the sclera  36  to form two ends of a line segment of about 6 mm in length, running through second measured mark  508   b  and running substantially perpendicular to the predetermined surgical axis C-C′  60  such that predetermined surgical axis C-C′  60  bisects the line segment that connects the two sclerotomy points  550   a,    550   b.  Those of skill in the art will appreciate that in this embodiment of the surgical procedure of the invention, it is not important which of the transscleral sutures  616   a, b  is established first, nor for that matter whether the surgical axis C-C′  60  has been considered to have been rotated clockwise or counterclockwise. 
     A second surgical mark  508   b  is then determined and made on the surface of the sclera  36  by measuring along the surgical axis C-C′  60  extending to the right of center of the pupil  20  to a point on sclera  36  about 4 mm posterior to the surgical limbus  542  of the eye  500 , and which is just posterior (with respect to the pupil  20 ) to a radius including the primary clear corneal incision  618 . Proximal sclerotomy points  552   a,    552   b  are marked on the sclera  36  to form two ends of a line segment of about 6 mm in length, running through second measured mark  508   b  and running substantially perpendicular to the predetermined surgical axis C-C′  60  such that predetermined surgical axis C-C′  60  bisects the line segment that connects the two sclerotomy points  552   a,    552   b.    
     A 27 gauge or similar hollow hypodermic or sclerotomy needle  510  can be used to make a sclerotomy at a first  550   a  of the two marks  550   a,    550   b  until the needle  510  becomes visible behind the pupil  20  of the eye  500 . Using one end of the first preloaded double armed transscleral suture  616   a,  the CTC needle  420   a  is inserted through the primary incision  618  into the eye  500  and docked into the sclerotomy needle  510 . Loading of the CTC needle  420   a  continues until its tip is well outside the eye  500  as shown. The hollow needle  510  is then removed and the CTC needle  420   a  is pulled until that first paired end of the suture  616   d  is entirely through the sclera  36 . Needle  420   a  is also removed from the first paired end of suture  616   d  as is shown in  FIG. 10A . The steps are then repeated for the second of the paired ends of transscleral suture  616   a,  as is also illustrated in  FIG. 10A . 
     The foregoing steps are then repeated for the second transscleral suture  616   b  as illustrated in  FIG. 10B , where sclerotomies are made at points  652   a, b  and needles  420   c, d  are cannulated through the hollow needle  520 . Needles  420   a, b, c, d  are decoupled from each of the paired ends. The paired ends of the first transscleral suture  616   a  can be pulled to bring the prosthesis  100 ,  200  into the eye  500  through incision  618  before the second transscleral suture  616   b  is fixed, in which case portions of the second transscleral suture  616   b  can remain protruding from the incision  618  to keep the prosthesis suspended as illustrated in  FIG. 10C , just as the loop  514  did in the first embodiment of the surgical method described above. The paired ends of the second transscleral suture  616   b  are then pulled to suspend the prosthesis in the eye  500 . In the alternative, the prosthetic can remain outside the eye  500  until both sutures  616   a, b  are placed. The sheet  108 ,  208  of prosthesis  100 ,  200  can be folded in half with a forceps and inserted through the incision  618 , and the paired ends of both of the transscleral sutures  616   a, b  can be pulled to suspend the prosthesis in the eye  500 . 
     As is the case with the first embodiment of the surgical method, the two paired ends of each suture  616   a, b  can then be pulled to adjust and substantially center the center aperture  106  of prosthesis  100 ,  200  to the optical axis A-A′  55  (or the visual axis visual axis visual axis B-B′  59  if desirable), depending upon the angle of the predetermined surgical axis surgical axis C-C′  60 , as illustrated in  FIG. 10D . The sutures can then be fixed as previously discussed in the sclera  36 . 
     Thus, embodiments of the surgical method of the invention permit the prosthesis  100 ,  200  of the invention to be surgically implanted at any predetermined angle of orientation of the surgical axis C-C′  60  over the 360° around virtually any axis, but particularly the optical axis A-A′  55  or the visual axis B-B′  59 . This makes implantation of non-spherical lenses, such as a toric lens  870  that is designed to correct a person&#39;s astigmatism easier to implement.  FIG. 11A  presents a visual representation of a patient&#39;s astigmatism commonly produced by a diagnostic instrument. The astigmatism is presented as an angled axis of astigmatism  852  centered on the optical axis of the eye  800 .  FIG. 11B  represents implantation of the prosthesis  100 ,  200  using a surgical axis C-C′  60 , predetermined to be substantially the same as the axis of astigmatism  852 . 
     By orienting the prosthesis  100 ,  200  in accordance with the axis of astigmatism  852 , the surgeon does not have to provide a correct orientation of the non-spherical lens. The surgeon must only orient the tonic lens optic  872  with the center aperture  106  of the prosthesis, in accordance with standard orientation established by the manufacturer for optic capture within the prosthesis  100 ,  200 . The standard orientation of the IOL  870  can be normalized to that disclosed in  FIGS. 6A, 6B and 9B , with the haptics  874   a, b  aligned to be captured by vertex features  104 ,  204  of prosthesis  100 ,  200 . Because toric lenses  870  are typically single piece lenses, they will be captured using optic capture as is also illustrated in  FIGS. 6A, 6B and 9B and 11B . 
     Those of skill in the art will recognize that certain modifications of the embodiments disclosed herein can be made without exceeding the intended scope of the invention. Modifications to the geometry of the prosthesis  100 ,  200 , the physical dimensions and the number of suture apertures can also be varied and will still be within the intended scope of the invention, as long as such geometries and dimensions provide sufficient points of contact that can produce the requisite stability of the prosthesis once implanted, as well as providing the requisite substantially centered alignment of the optical  55  or visual  59  axis of the eye with IOL optics  72 ,  82  captured thereon. For example, the geometry of the prosthesis could be hexagonal, pentagonal, or even star shaped. Additional vertices could also be provided along the sides of rectangular prosthesis  100  without changing its geometry. The increased numbers of vertices of the geometry could provide additional suture apertures if desirable, which would lead to additional points of contact and greater stability. While the number of transscleral sutures  616  should be kept to a minimum to simplify the procedure, additional points of contact may be desirable. 
     The minimum points of contact necessary to prevent rotation of the prosthesis  100 ,  200  can be provided through at least two transscleral sutures  616  providing at least three points of contact between the sclera  36  of the eye  500  and prosthesis  100 ,  200  through apertures  102 ,  103  or  202 ,  203 . Any lesser number could lead to undesired rotation of the implanted prosthesis, and therefore the IOL  70 ,  80 ,  870 . When implanted as illustrated in  FIG. 9B , the three apertures  202 ,  203   a, b  of triangular embodiment  200  of the prosthesis  100 ,  200  (located proximally to its vertices) is an example of a geometry providing a minimum number of three points of contact. While there are actually four attachment points provided by the paired ends of the first and second looped transscleral sutures  616   d, p,  the points of contact as referred to herein are made with reference to the prosthesis  100 ,  200  itself. The second suture  616   p  provides two of the points of contact with the prosthesis  200 , because it is looped through the two paired apertures  203   a, b.    
     The rectangular embodiment  100  of prosthesis  100 ,  200 , when implanted as illustrated in  FIG. 9A , has two paired suture apertures ( 102   a, b  and  103   a, b ) located proximally to each one of its four vertices, and thus increases the number of points of contact between it and the sclera  36  through the sutures  616   d, p  to four. It will be appreciated that by looping both transscleral sutures  616   d, p  through paired apertures  102   a, b  and  103   a, b  respectively, it will be appreciated that stability has been increased without adding additional sutures  616 , and therefore the number of sclerotomies required for implantation. 
     It will be further appreciated in view of  FIG. 12  that, while limiting the number of transscleral sutures  616  is preferable with regard to simplifying the procedure and limiting its invasiveness, greater stability for the implanted prosthesis  100 ,  200  may be achieved if each aperture has its own transscleral suture  616  looped therethrough, rather than looping through pairs of apertures as described above. In this case, rather than marking just two scleral points on either side of the surgical axis  60  as described for embodiments of the surgical method above, two pairs of such points  1052   a, b  could be made, so that each aperture has its own suture  616  as illustrated. 
     It will be further appreciated that rather than looping each suture  616  of  FIG. 12 , the same number of points of contact could be provided to the sclera using single sutures instead. If the diameters of the apertures  202 ,  203   a, b  are reduced, each suture  616  could be cannulated through the smaller diameter aperture and constrained therein by creating a flange at the end to create a flange that prevents the suture from slipping back through. Doing so would accomplish reducing the number of sclerotomies required from four to three. These sutures could be affixed to the apertures pre-surgery and would still permit centration adjustment before fixation to the sclera  36 . It will be appreciated that the sclerotomy points would be in substantially the same place as the markers established along the surgical axis. It will be further appreciated that this could also be accomplished with one looped suture passed through the base vertices  203   a, b  of triangular embodiment  200  and a flanged suture pre-secured to vertex  202 . Finally, it will be appreciated that the flanged longitudinal sutures will not decrease the number of sclerotomies for those geometries of prosthesis  100 ,  200  having even numbers of vertices that can be at least paired with a looped suture. 
     It should be noted the precise implanted position in the space posterior to the sulcus  18  along the optical visual axis A-A′  59   55  or visual  59  visual axis B-B′  59  axis can also vary, provided the IOL  70 ,  80  is compensated as necessary to provide the proper focal length for satisfactory resolution of the image on the retina  30 . Additionally, when performing embodiments of the surgical method of the invention, it will be appreciated that certain steps can be performed in a different order from that disclosed without impacting the ultimate result achieved. For example, the marks  508  made along the surgical axis  60  from which sclerotomy points  350 ,  352  are derived and marked can be made before any incisions are made, or they can be determined right before they are needed. 
     Likewise, the first and second double-armed sutures  616  can be prepared prior to the making of any incisions  618 ,  620 . The prosthesis  100 ,  200  could be provided for the surgical methods of the invention with pre-cannulated pre-loaded sutures and surgical needles already coupled thereto as described herein. In addition, it will be appreciated that some surgeons may not physically mark the eye  500  with the above-described marks at all, but the sclerotomies will still be marked in a virtual sense by making the sclerotomies in substantially the same places based on the same considerations as disclosed herein, even if by the experienced eye of a surgeon. 
     Finally, those of skill in the art will appreciate that there is a certain tolerable margin of error with regard to the precision with which those points are determined, and the measurements made to determine them. Thus, the word “substantially” is often used herein to modify such determinations to account for that margin. This is also true with regard to centration of the optic centroid, the central aperture centroid and the optical or visual axes. This is a process that is also typically done by eye, However, the process has been described herein with regard to the ideal centration of the IOL, with the recognition that the ideal is not easily achievable by eye, but is the ideal goal of the surgeon, nevertheless. Thus, substantially centered is defined to be within an acceptable margin of error for a successful outcome.