Abstract:
A scleral prosthesis includes an elongated body and an insert. The body includes (i) opposing first and second free ends and (ii) multiple first portions that form the first end and part of a remainder of the body between the ends. The first portions are separated along at least about half of a total length of the body by empty space such that the first portions meet at a point between the ends and are not connected to each other between that point and the first end. The ends are wider than the remainder. The insert is configured to be placed between the first portions and to substantially fill the empty space. The first portions are biased so that they maintain separation from one another without external interference but are configured to be pushed towards each other in order to reduce a width of the first end. The insert, when placed between the first portions, keeps the first portions separated and prevents the first portions from being pushed together and reducing the width of the first end.

Description:
CROSS-REFERENCE TO RELATED PATENT DOCUMENTS AND PRIORITY CLAIM 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 14/975,152 filed on Dec. 18, 2015, which claims priority under 35 U.S.C. §120 as a continuation of U.S. patent application Ser. No. 14/570,630 filed on Dec. 15, 2014, which claims priority under 35 U.S.C. §120 as a continuation of U.S. patent application Ser. No. 13/654,249 filed on Oct. 17, 2012 (now U.S. Pat. No. 8,911,496), which claims priority under 35 U.S.C. §120 as a continuation-in-part of U.S. patent application Ser. No. 11/827,382 filed on Jul. 11, 2007 (now U.S. Pat. No. 8,409,277), which claims priority to U.S. Provisional Patent Application No. 60/819,995 filed on Jul. 11, 2006. All of these applications are hereby incorporated by reference. 
         [0002]    This application is related to the following U.S. patent applications and issued patents:
       (1) U.S. Pat. No. 6,007,578 entitled “Scleral Prosthesis for Treatment of Presbyopia and Other Eye Disorders” issued on Dec. 28, 1999;   (2) U.S. Pat. No. 6,280,468 entitled “Scleral Prosthesis for Treatment of Presbyopia and Other Eye Disorders” issued on Aug. 28, 2001;   (3) U.S. Pat. No. 6,299,640 entitled “Scleral Prosthesis for Treatment of Presbyopia and Other Eye Disorders” issued on Oct. 9, 2001;   (4) U.S. Pat. No. 5,354,331 entitled “Treatment of Presbyopia and Other Eye Disorders” issued on Oct. 11, 1994;   (5) U.S. Pat. No. 5,465,737 entitled “Treatment of Presbyopia and Other Eye Disorders” issued on Nov. 14, 1995;   (6) U.S. Pat. No. 5,489,299 entitled “Treatment of Presbyopia and Other Eye Disorders” issued on Feb. 6, 1996;   (7) U.S. Pat. No. 5,503,165 entitled “Treatment of Presbyopia and Other Eye Disorders” issued on Apr. 2, 1996;   (8) U.S. Pat. No. 5,529,076 entitled “Treatment of Presbyopia and Other Eye Disorders” issued on Jun. 25, 1996;   (9) U.S. Pat. No. 5,722,952 entitled “Treatment of Presbyopia and Other Eye Disorders” issued on Mar. 3, 1998;   (10) U.S. Pat. No. 6,197,056 entitled “Segmented Scleral Band for Treatment of Presbyopia and Other Eye Disorders” issued on Mar. 6, 2001;   (11) U.S. Pat. No. 6,579,316 entitled “Segmented Scleral Band for Treatment of Presbyopia and Other Eye Disorders” issued on Jun. 17, 2003;   (12) U.S. Pat. No. 6,926,727 entitled “Surgical Blade for Use with a Surgical Tool for Making Incisions for Scleral Eye Implants” issued on Aug. 9, 2005;   (13) U.S. Pat. No. 6,991,650 entitled “Scleral Expansion Device Having Duck Bill” issued on Jan. 31, 2006;   (14) U.S. Pat. No. 7,189,248 entitled “System and Method for Making Incisions for Scleral Eye Implants” issued on Mar. 13, 2007;   (15) U.S. Pat. No. 7,909,780 entitled “System and Method for Determining a Position for a Scleral Pocket for a Scleral Prosthesis” issued on Mar. 22, 2011;   (16) U.S. Pat. No. 7,785,367 entitled “Scleral Prosthesis for Treatment of Presbyopia and Other Eye Disorders” issued on Aug. 31, 2010;   (17) U.S. patent application Ser. No. 11/199,591 entitled “Surgical Blade for Use with a Surgical Tool for Making Incisions for Scleral Eye Implants” filed on Aug. 8, 2005 (now U.S. Pat. No. 8,361,098);   (18) U.S. patent application Ser. No. 11/252,369 entitled “Scleral Expansion Device Having Duck Bill” filed on Oct. 17, 2005;   (19) U.S. patent application Ser. No. 11/323,283 entitled “Surgical Blade for Use with a Surgical Tool for Making Incisions for Scleral Eye Implants” filed on Dec. 30, 2005 (now U.S. Pat. No. 8,500,767);   (20) U.S. Pat. No. 7,824,423 entitled “System and Method for Making Incisions for Scleral Eye Implants” issued on Nov. 2, 2010;   (21) U.S. patent application Ser. No. 11/322,728 entitled “Segmented Scleral Band for Treatment of Presbyopia and Other Eye Disorders” filed on Dec. 30, 2005 (now U.S. Pat. No. 8,663,205); and   (22) U.S. patent application Ser. No. 11/323,752 entitled “Segmented Scleral Band for Treatment of Presbyopia and Other Eye Disorders” filed on Dec. 30, 2005 (now U.S. Pat. No. 8,663,206).
 
All of these U.S. patents and patent applications are hereby incorporated by reference.
       
 
     
    
     TECHNICAL FIELD 
       [0025]    This disclosure is generally directed to eye implants and associated devices, and more specifically to a scleral prosthesis for treating presbyopia and other eye disorders and related devices and methods. 
       BACKGROUND 
       [0026]    In order for the human eye to have clear vision of an object at different distances (especially near objects), the effective focal length of the eye&#39;s crystalline lens is adjusted to keep an image of the object focused as sharply as possible on the retina. This change in effective focal length is known as “accommodation” and is accomplished by varying the shape of the crystalline lens in the eye. Generally, in the unaccommodated emmetropic eye, the curvature of the lens is such that distant objects are sharply imaged on the retina. In the unaccommodated eye, near objects are not focused sharply on the retina because their images lie behind the retinal surface. In order to visualize a near object clearly, the curvature of the crystalline lens is increased, thereby increasing its refractive power and causing the image of the near object to fall on the retina. 
         [0027]    The change in the shape of the crystalline lens is accomplished by the action of certain muscles and structures within the eyeball or the “globe” of the eye. The lens is located in the forward part of the eye immediately behind the pupil. It has the shape of a classical biconvex optical lens, meaning it has a generally circular cross section with two convex refracting surfaces. The lens is located generally on the optical axis of the eye, which is typically the straight line from the center of the cornea to the macula in the retina at the posterior portion of the globe. In the unaccommodated eye, the curvature of the posterior surface of the lens (the surface adjacent to the vitreous body) is somewhat greater than the curvature of the anterior surface. 
         [0028]    The lens is closely surrounded by a membranous capsule that serves as an intermediate structure in the support and actuation of the lens. The lens and its capsule are suspended on the optical axis behind the pupil by a circular assembly of radially directed elastic fibers called “zonules.” The zonules are attached at their inner ends to the lens capsule and at their outer ends to the ciliary body and indirectly to the ciliary muscle. The ciliary muscle is a muscular ring of tissue located just within the sclera, the outer supporting structure of the eye. 
         [0029]    According to the classical theory of accommodation originating with Helmholtz, the ciliary muscle is relaxed in the unaccommodated eye and therefore assumes its largest diameter. The relatively large diameter of the ciliary muscle in this condition causes a tension on the zonules, which pull radially outward on the lens capsule. This causes the equatorial diameter of the lens to increase slightly and decreases the anterior-posterior dimension of the lens at the optical axis. In other words, the tension on the lens capsule causes the lens to assume a flattened state where the curvature of the anterior surface, and to some extent the posterior surface, is less than it would be in the absence of the tension. In this state, the refractive power of the lens is relatively low, and the eye is focused for clear vision on distant objects. 
         [0030]    According to the classical theory, when the eye is intended to be focused on a near object, the ciliary muscle contracts. This contraction causes the ciliary muscle to move forward and inward, thereby relaxing the outward pull of the zonules on the equator of the lens capsule. This reduced zonular tension allows the elastic capsule of the lens to contract, causing an increase in the anterior-posterior dimension of the lens at the optical axis (meaning the lens becomes more spherical). This results in an increase in the optical power of the lens. Because of topographical differences in the thickness of the lens capsule, the central anterior radius of curvature may change more than the central posterior radius of curvature. This is the accommodated condition of the eye, where images of near objects fall sharply on the retina. 
         [0031]    Presbyopia is the universal decrease in the amplitude of accommodation, which is typically observed in individuals over forty years of age. In a person having normal vision or “emmetropic” eyes, the ability to focus on near objects is gradually lost. As a result, the individual comes to need glasses for tasks requiring near vision, such as reading. 
         [0032]    According to the conventional view, the amplitude of accommodation of the aging eye is decreased because of the loss of elasticity of the lens capsule and/or sclerosis of the lens with age. Consequently, even though the radial tension on the zonules is relaxed by contraction of the ciliary muscle, the lens does not assume a greater curvature. According to this conventional view, it is not possible to restore the accommodative power to the presbyopic eye by any treatment. The loss of elasticity of the lens and its capsule is seen as irreversible. One solution to the problems presented by presbyopia is to use corrective lenses for close work or possibly bifocal lenses if corrective lenses are required for distant vision. Other solutions may include surgically reshaping the cornea of the eye or implanting a presbyopic intra-ocular lens in the eye 
         [0033]    Contrary to the conventional view, it is possible to restore the accommodative power to a presbyopic eye by implanting scleral prostheses within the sclera of the eye. For each individual scleral prosthesis, an incision is made in the sclera of the eye, such as near the plane of the equator of the crystalline lens. The incision is then extended under the surface of the sclera to form a scleral “tunnel,” and a scleral prosthesis is placed within the tunnel. A typical scleral prosthesis could be formed from a generally rectangular-shaped bar approximately five millimeters long, one and a half millimeters wide, and one millimeter tall. One or multiple scleral prostheses may be implanted in a patient&#39;s eye to partially or completely restore the accommodative power to a presbyopic eye. The same or similar technique can also be used to treat glaucoma, ocular hypertension, elevated intraocular pressure, or other eye disorders. This technique is described more fully in the U.S. patents and patent applications incorporated by reference above. 
       SUMMARY 
       [0034]    This disclosure provides a scleral prosthesis for treating presbyopia and other eye disorders and related devices and methods. 
         [0035]    In a first embodiment, a scleral prosthesis includes an elongated body configured to be implanted into scleral tissue of an eye. The elongated body includes (i) opposing first and second free ends and (ii) multiple first portions that form the first end of the body and part of a remainder of the body between the first and second ends. The first portions of the body are separated along at least about half of a total length of the elongated body by empty space such that the first portions meet at a point between the first and second ends of the body and are not connected to each other between that point and the first end of the body. The first and second ends are wider than the remainder of the body. The scleral prosthesis also includes an insert configured to be placed between the first portions of the body and to substantially fill the empty space. The first portions of the body are biased so that they maintain separation from one another without external interference but are configured to be pushed towards each other in order to reduce a width of the first end. The insert, when placed between the first portions of the body, keeps the first portions of the body separated and prevents the first portions of the body from being pushed together and reducing the width of the first end. 
         [0036]    In a second embodiment, a method includes obtaining an elongated body configured to be implanted into scleral tissue of an eye. The elongated body includes (i) opposing first and second free ends and (ii) multiple first portions that form the first end of the body and part of a remainder of the body between the first and second ends. The first portions of the body are separated along at least about half of a total length of the elongated body by empty space such that the first portions meet at a point between the first and second ends of the body and are not connected to each other between that point and the first end of the body. The first and second ends are wider than the remainder of the body. The method also includes placing an insert between the first portions of the body, where the insert is configured to substantially fill the empty space. The first portions of the body are biased so that they maintain separation from one another without external interference but are configured to be pushed towards each other in order to reduce a width of the first end. The insert, when placed between the first portions of the body, keeps the first portions of the body separated and prevents the first portions of the body from being pushed together and reducing the width of the first end. 
         [0037]    In a third embodiment, a method includes forming an elongated body configured to be implanted into scleral tissue of an eye. The elongated body includes (i) opposing first and second free ends and (ii) multiple first portions that form the first end of the body and part of a remainder of the body between the first and second ends. The first portions of the body are separated along at least about half of a total length of the elongated body by empty space such that the first portions meet at a point between the first and second ends of the body and are not connected to each other between that point and the first end of the body. The first and second ends are wider than the remainder of the body. The method also includes forming an insert configured to be placed between the first portions of the body and to substantially fill the empty space. The first portions of the body are biased so that they maintain separation from one another without external interference but are configured to be pushed towards each other in order to reduce a width of the first end. The insert, when placed between the first portions of the body, keeps the first portions of the body separated and prevents the first portions of the body from being pushed together and reducing the width of the first end. 
         [0038]    Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0039]    For a more complete understanding of this disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawing, in which: 
           [0040]      FIGS. 1A and 1B  illustrate a first example scleral prosthesis in accordance with this disclosure; 
           [0041]      FIGS. 2A and 2B  illustrate a second example scleral prosthesis in accordance with this disclosure; 
           [0042]      FIGS. 3A through 3F  illustrate a third example scleral prosthesis in accordance with this disclosure; 
           [0043]      FIG. 4  illustrates a fourth example scleral prosthesis in accordance with this disclosure; 
           [0044]      FIGS. 5A through 5G  illustrate a fifth example scleral prosthesis in accordance with this disclosure; 
           [0045]      FIGS. 6A through 6G  illustrate a sixth example scleral prosthesis in accordance with this disclosure; 
           [0046]      FIGS. 7A through 7G  illustrate a seventh example scleral prosthesis in accordance with this disclosure; 
           [0047]      FIGS. 8A through 8F  illustrate an example insertion of a scleral prosthesis into a patient&#39;s eye in accordance with this disclosure; 
           [0048]      FIGS. 9A through 9C  illustrate an example threader tube used to insert a scleral prosthesis into a patient&#39;s eye in accordance with this disclosure; 
           [0049]      FIGS. 10A and 10B  illustrate an example surgical blade used to create a scleral tunnel for receiving a scleral prosthesis in accordance with this disclosure; 
           [0050]      FIGS. 11A through 11D  illustrate an eighth example scleral prosthesis in accordance with this disclosure; and 
           [0051]      FIGS. 12A and 12B  illustrate a ninth example scleral prosthesis in accordance with this disclosure; 
           [0052]      FIGS. 13A through 13D  illustrate a tenth example scleral prosthesis in accordance with this disclosure; 
           [0053]      FIGS. 14A and 14B  illustrate an eleventh example scleral prosthesis in accordance with this disclosure; 
           [0054]      FIG. 15  illustrates an example method for inserting a scleral prosthesis into a patient&#39;s eye in accordance with this disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0055]      FIGS. 1A and 1B  illustrate a first example scleral prosthesis  100  in accordance with this disclosure. The embodiment of the scleral prosthesis  100  shown in  FIGS. 1A and 1B  is for illustration only. Other embodiments of the scleral prosthesis  100  could be used without departing from the scope of this disclosure. 
         [0056]    As shown in  FIGS. 1A and 1B , the scleral prosthesis  100  has two opposing ends  102 - 104 , atop surface  106 , and a bottom surface  108 . One end  102  of the prosthesis  100  includes a generally cylindrical area  110  with a flat bottom forming a base on which the prosthesis  100  sits. The other end  104  of the prosthesis  100  is divided or split into multiple portions  112   a - 112   b . Each of these portions  112   a - 112   b  includes a generally cylindrical area  114  with a flat bottom, which collectively form another base on which the prosthesis  100  sits. 
         [0057]    In this example, the portions  112   a - 112   b  of the prosthesis  100  span a majority of the length of the prosthesis  100 , meaning the prosthesis  100  is split along at least half of its length (or some other substantial portion of its length). The portions  112   a - 112   b  are generally biased so that they remain separated from one another without external interference. The portions  112   a - 112   b  may be biased such that they can be pushed towards each other or together but then separate after release. Also, the portions  112   a - 112   b  may not be excessively biased to the point where they tear through an incision in the patient&#39;s eye or pull the prosthesis  100  out of a scleral tunnel. Also, the cylindrical areas  110  and  114  project out from the sides of the prosthesis  100 , meaning the cylindrical areas  110  and  114  form bases that are wider than the middle portion of the prosthesis  100 . In addition, in this example, the top surface  106  of the prosthesis  100  is generally curved, and the bottom surface  108  could be generally flat or curved. 
         [0058]    In this example embodiment, the scleral prosthesis  100  can be implanted within a scleral tunnel in a patient&#39;s eye. For example, the scleral prosthesis  100  can be implanted such that the cylindrical areas  110  and  114  remain outside of the scleral tunnel. Also, the flat bottoms of the cylindrical areas  110  and  114  can lie on the surface of the patient&#39;s eye outside of the scleral tunnel. To implant the scleral prosthesis  100  in the scleral tunnel, the portions  112   a - 112   b  of the scleral prosthesis  100  could be pushed together and pulled through the scleral tunnel. This may help to reduce the width or cross-sectional area of the end  104  of the scleral prosthesis  100  as the prosthesis  100  is pulled through the scleral tunnel during implantation. However, any other suitable technique could be used to implant the scleral prosthesis  100  in a scleral tunnel. 
         [0059]    The scleral tunnel in which the scleral prosthesis  100  is implanted can be formed near the ciliary body of a patient&#39;s eye. Once implanted in a scleral tunnel, the scleral prosthesis  100  helps to, for example, increase the amplitude of accommodation of the patient&#39;s eye. The scleral prosthesis  100  could also help to treat other eye conditions, such as glaucoma, ocular hypertension, elevated intraocular pressure, or other eye disorders. In some embodiments, multiple prostheses (such as four) are implanted in a patient&#39;s eye, and the ends of the prostheses are “free” (not attached to the ends of other prostheses). 
         [0060]    By making the ends of the scleral prosthesis  100  wider than its middle portion, various benefits could be obtained, such as stabilization of the prosthesis  100 . For example, with wider ends, it is less likely that the scleral prosthesis  100  would turn or rotate within a scleral tunnel after implantation. Also, the wider ends help to lock the scleral prosthesis  100  into place and impede movement of the scleral prosthesis  100 . In addition, the wider ends make it less likely that the scleral prosthesis  100  can be inadvertently ejected out of the scleral tunnel after implantation. 
         [0061]    In particular embodiments, the prosthesis  100  in  FIGS. 1A and 1B  may be formed from a single integrated piece of material, such as polymethyl methacrylate (“PMMA”), polyether-ether ketone (“PEEK”), or other suitable material(s). Also, the scleral prosthesis  100  could have any suitable size and dimensions, and scleral prostheses  100  of different sizes could be provided. For example, different-sized scleral prostheses  100  could have different lengths, such as lengths of 3.6, 3.8, 4.0, and 4.2 millimeters from the inner edges of the cylindrical areas  110  and  114  of the prostheses  100 . 
         [0062]      FIGS. 2A and 2B  illustrate a second example scleral prosthesis  200  in accordance with this disclosure. The embodiment of the scleral prosthesis  200  shown in  FIGS. 2A and 2B  is for illustration only. Other embodiments of the scleral prosthesis  200  could be used without departing from the scope of this disclosure. 
         [0063]    The scleral prosthesis  200  in  FIGS. 2A and 2B  is similar to the scleral prosthesis  100  of  FIGS. 1A and 1B . In this example embodiment, the scleral prosthesis  200  includes opposing ends  202 - 204 . In this example, both ends  202 - 204  are split or divided into multiple portions  206   a - 206   b  and  208   a - 208   b , respectively. Each of these end portions  206   a - 206   b  and  208   a - 208   b  includes a generally cylindrical area  210  or  212 , which could have flat bottoms collectively define two bases for the scleral prosthesis  200 . 
         [0064]    In this example embodiment, the scleral prosthesis  200  can be implanted within a scleral tunnel in a patient&#39;s eye, such as by implanting the scleral prosthesis  200  so that the cylindrical areas  210  and  212  remain outside of the scleral tunnel. Also, the flat bottom portions of the cylindrical areas  210  and  212  can lie on the surface of the patient&#39;s eye outside of the scleral tunnel. Further, the cylindrical areas  210  and  212  project out from the sides of the prosthesis  200 , forming bases that are wider than the middle portion of the prosthesis  200 . As noted above, this may help to stabilize the scleral prosthesis  200 , such as by reducing or preventing rotation, locking the prosthesis  200  into place, impeding movement of the prosthesis  200 , and reducing the likelihood that the prosthesis  200  can exit the scleral tunnel. In addition, in this example, the top surface of the prosthesis  200  is generally curved, and the bottom surface could be generally flat or curved. 
         [0065]    To implant the scleral prosthesis  200  in the scleral tunnel, the portions  206   a - 206   b  or  208   a - 208   b  of the scleral prosthesis  200  can be pushed together and pulled through the scleral tunnel. An example of this is shown in  FIG. 2B . Here, a tool  290  has two hooked ends  292  that can hook around or onto the cylindrical areas  212  of the scleral prosthesis  200 . The tool  290  is then used to push the split portions  208   a - 208   b  of the scleral prosthesis  200  together, and the prosthesis  200  can be pulled into the scleral tunnel. However, any other suitable technique could be used to implant the scleral prosthesis  200  in a scleral tunnel. 
         [0066]    In particular embodiments, the prosthesis  200  in  FIGS. 2A and 2B  may be formed from a single integrated piece of material, such as PMMA, PEEK, or other suitable material(s). The scleral prosthesis  200  could also have any suitable size and dimensions, and scleral prostheses  200  of different sizes could be provided. 
         [0067]      FIGS. 3A through 3F  illustrate a third example scleral prosthesis  300  in accordance with this disclosure. The embodiment of the scleral prosthesis  300  shown in  FIGS. 3A through 3F  is for illustration only. Other embodiments of the scleral prosthesis  300  could be used without departing from the scope of this disclosure. 
         [0068]    As shown in  FIGS. 3A through 3C , the scleral prosthesis  300  has two opposing ends  302 - 304 , a top surface  306 , and a bottom surface  308 . One end  302  of the prosthesis  300  is split or divided into multiple portions  310   a - 310   b , and the other end  304  of the prosthesis  300  is split or divided into multiple portions  312   a - 312   b.    
         [0069]    In this example, the portions  310   a - 310   b  of the prosthesis  300  span less than a quarter of the length of the prosthesis  300  (or some other less substantial portion of its length), and the portions  312   a - 312   b  of the prosthesis  300  span more than half of the length of the prosthesis  300  (or some other more substantial portion of its length). Also, in this example, the ends  302 - 304  of the prosthesis  300  have areas  314 - 316 , respectively, that are more triangular in shape. As shown in  FIG. 3B , the areas  314  at the end  302  of the scleral prosthesis  300  have surfaces that generally face the opposing end  304 . Also, as shown in  FIG. 3B , the areas  316  at the end  304  of the scleral prosthesis  300  have surfaces that are more hook-shaped (the areas  316  hook back towards the opposing end  302  of the scleral prosthesis  300 ). These areas  314  and  316  may also include generally flat bottom surfaces that form bases for the prosthesis  300 . 
         [0070]    In this example embodiment, the scleral prosthesis  300  can be implanted within a scleral tunnel in a patient&#39;s eye, such as by implanting the scleral prosthesis  300  so that the areas  314  and  316  remain outside of the scleral tunnel. Also, the flat bottom portions of the areas  314  and  316  can lie on the surface of the patient&#39;s eye outside of the scleral tunnel. Further, the areas  314  and  316  project out from the sides of the prosthesis  300  to form bases wider than the middle portion of the prosthesis  300 . Again, the wider ends may provide certain benefits for the scleral prosthesis  300 , such as stabilization of the prosthesis  300 . In addition, in this example, the top surface  306  and the bottom surface  308  of the prosthesis  300  are generally curved. 
         [0071]    In particular embodiments, the prosthesis  300  in  FIGS. 3A through 3C  may be formed from a single integrated piece of material, such as PMMA, PEEK, or other suitable material(s). Also, the scleral prosthesis  300  could have any suitable size and dimensions, and scleral prostheses  300  of different sizes could be provided. 
         [0072]    Examples of differently sized and dimensioned prostheses are shown in  FIGS. 3D through 3F , which illustrate four different prostheses  300   a - 300   d . The prostheses  300   a - 300   d  are similar to one another with slight changes in their structure. For example, the prosthesis  300   a  has a larger arch and flat bottom surfaces at its ends, while the prosthesis  300   c  has a smaller arch and flat bottom surfaces at its ends. The prosthesis  300   b  has a larger arch and slanted bottom surfaces at its ends, while the prosthesis  300   d  has a smaller arch and slanted bottom surfaces at its ends. 
         [0073]    The prostheses  300   a - 300   d  in  FIGS. 3D through 3F  could have any suitable sizes and dimensions. For example, the prostheses  300   a - 300   d  could be 5,366 microns in length. A thickness (measured top-to-bottom) at the middle (measured end-to-end) of the prostheses  300   a - 300   d  could have various values, such as 831, 833, and 839 microns. The arch (measured from the tips of the prostheses to the top of the arch) of the prostheses  300   a - 300   d  could also have various values, such as 212, 311, and 386 microns. 
         [0074]      FIG. 4  illustrates a fourth example scleral prosthesis  400  in accordance with this disclosure. The embodiment of the scleral prosthesis  400  shown in  FIG. 4  is for illustration only. Other embodiments of the scleral prosthesis  400  could be used without departing from the scope of this disclosure. 
         [0075]    In this example, the scleral prosthesis  400  in  FIG. 4  is similar to the prosthesis  300  shown in  FIGS. 3A through 3C . Here, the scleral prosthesis  400  includes two opposing ends  402 - 404 , where the end  404  is split or divided into multiple portions  406   a - 406   b.    
         [0076]    The prosthesis  400  also includes an insert  408  placed between or around the multiple portions  406   a - 406   b  of the end  404  of the prosthesis  400 . The insert  408  can be permanently or removably placed between or around the portions  406   a - 406   b  of the end  404  of the prosthesis  400 . For example, the insert  408  could be placed between or around the portions  406   a - 406   b  of the end  404  after the prosthesis  400  has been implanted in a scleral tunnel in a patient&#39;s eye. The insert  408  could later be removed, such as to facilitate removal of the prosthesis  400  from the scleral tunnel. 
         [0077]    The insert  408  may generally help to stabilize the prosthesis  400  (in addition to the stabilization already provided by the wider ends). For example, the insert  408  could help to prevent the portions  406   a - 406   b  of the prosthesis  400  from separating excessively, which could pull the opposite end  402  through the scleral tunnel and force the prosthesis  400  out of the tunnel completely. The insert  408  could also function to reduce or prevent rotation of the prosthesis  400  within the scleral tunnel. For instance, the insert  408  may help to ensure that the end  404  of the prosthesis  400  maintains a desired width and therefore remains wide enough to prevent the prosthesis  400  from rolling over once implanted in the scleral tunnel. Moreover, the insert  408  can be inserted into or around the prosthesis  400  only after the prosthesis  400  has been implanted, which enables the portions  406   a - 406   b  of the prosthesis  400  to be pushed together during implantation while preventing portions  406   a - 406   b  from coming together after implantation (reducing the likelihood that the prosthesis  400  can exit the scleral tunnel). 
         [0078]    The insert  408  could be attached or coupled to the prosthesis  400  in any suitable manner. For example, the insert  408  could have one or more structures that engage one or more corresponding structures of the portions  406   a - 406   b  of the prosthesis  400 , such as male structures on the insert  408  that engage female structures on the prosthesis body. The insert  408  could also be attached to the prosthesis  400  using sutures or looped around the prosthesis  400 . The insert  408  could be attached or coupled to the prosthesis  400  in any other suitable manner. 
         [0079]      FIGS. 5A through 5G  illustrate a fifth example scleral prosthesis  500  in accordance with this disclosure. The embodiment of the scleral prosthesis  500  shown in  FIGS. 5A through 5G  is for illustration only. Other embodiments of the scleral prosthesis  500  could be used without departing from the scope of this disclosure. 
         [0080]    As shown in  FIG. 5A , the scleral prosthesis  500  has two opposing ends  502 - 504 . In this example, only one end  504  of the prosthesis  500  is split or divided into multiple portions  506   a - 506   b  (although both could be). As shown in  FIG. 5B , the ends of the prosthesis  500  generally have an oval cross-section. Except for the more oval cross-section and the undivided end  502 , the overall shape of the prosthesis  500  is similar to the shape of the prosthesis  300 . 
         [0081]    As shown here, portions  508 - 510  of the ends  502 - 504  of the prosthesis  500  are hook-shaped, where the portions  508  of the end  502  are hooked back towards the end  504  and the portions  510  of the end  504  are hooked back towards the end  502 . These portions  508 - 510  of the prosthesis  500  could also lie outside of a scleral tunnel and rest on the surface of a patient&#39;s eye. Again, the ends  502 - 504  of the prosthesis  500  are wider than the middle, helping to stabilize the prosthesis  500 . 
         [0082]    In this example, the prosthesis  500  also includes ridges  512  along the inner sides of the portions  506   a - 506   b . The ridges  512  generally travel lengthwise along the portions  506   a - 506   b  of the prosthesis  500 . The ridges  512  may or may not link up to each other along the curved intersection of the portions  506   a - 506   b . The ridges  512  may have any suitable height, width, or shape. 
         [0083]    The prosthesis  500  could have the dimensions shown in  FIGS. 5B through 5G . These dimensions are for illustration only. In these figures, the dimensions are expressed as numbers in brackets (representing dimensions in inches) over numbers without brackets (representing dimensions in millimeters). Dimensions associated with a radius of curvature are preceded by the letter “R” (such as in “R6.168”). In addition, the diagram shown in  FIG. 5E  represents the cross-section of the prosthesis  500  along line A-A in  FIG. 5D , and the diagram shown in  FIG. 5G  represents the cross-section of the prosthesis  500  along line B-B in  FIG. 5F . As shown in  FIG. 5G , the prosthesis  500  could (but need not) be hollow within the undivided portion of the prosthesis  500  near the end  502  and may or may not be filled with a liquid, gel, or other material. 
         [0084]    As explained in more detail below, an insert can be placed between or around the multiple portions  506   a - 506   b  of the end  504  of the prosthesis  500 . The insert can be permanently or removably placed between or around the portions  506   a - 506   b  of the end  504  of the prosthesis  500 . For example, the insert could be placed between or around the portions  506   a - 506   b  of the end  504  after the prosthesis  500  has been implanted in a scleral tunnel in a patient&#39;s eye. The insert could later be removed, such as to facilitate removal of the prosthesis  500  from the scleral tunnel. 
         [0085]    The insert may generally help to stabilize the prosthesis  500  (in addition to the stabilization already provided by the wider ends). For example, the insert could help to prevent the portions  506   a - 506   b  of the prosthesis  500  from separating excessively, which could pull the opposite end  502  through the scleral tunnel and force the prosthesis  500  out of the tunnel completely. The insert could also function to reduce or prevent rotation of the prosthesis  500  within the scleral tunnel. For instance, the insert may help to ensure that the end  504  of the prosthesis  500  maintains a desired width and therefore remains wide enough to prevent the prosthesis  500  from rolling over once implanted in the scleral tunnel. Moreover, the insert can be inserted into or around the prosthesis  500  only after the prosthesis  500  has been implanted, which enables the portions  506   a - 506   b  of the prosthesis  500  to be pushed together during implantation but prevents portions  506   a - 506   b  from coming together after implantation (reducing the likelihood that the prosthesis  500  can exit the scleral tunnel). 
         [0086]      FIGS. 6A through 6G  illustrate a sixth example scleral prosthesis  600  in accordance with this disclosure. The embodiment of the scleral prosthesis  600  shown in  FIGS. 6A through 6G  is for illustration only. Other embodiments of the scleral prosthesis  600  could be used without departing from the scope of this disclosure. 
         [0087]    As shown in  FIG. 6A , the scleral prosthesis  600  has two opposing ends  602 - 604 . In this example, again only one end  604  of the prosthesis  600  is split or divided into multiple portions  606   a - 606   b  (although both ends could be divided). As shown in  FIG. 6B , the prosthesis  600  generally has a more rectangular cross-section, where the bottom surfaces of the ends  602 - 604  are flatter than in the prosthesis  500 . 
         [0088]    As shown here, portions  608 - 610  of the ends  602 - 604  of the prosthesis  600  are hook-shaped, and the prosthesis  600  includes ridges  612  along the inner sides of the portions  606   a - 606   b . The ridges  612  generally travel lengthwise along the portions  606   a - 606   b  of the prosthesis  600  and may or may not be linked along the curved intersection of the portions  606   a - 606   b . Again, the ends  602 - 604  of the prosthesis  600  are wider than the middle, helping to stabilize the prosthesis  600 . 
         [0089]    The prosthesis  600  could have the dimensions shown in  FIGS. 6B through 6G . These dimensions are for illustration only. In these figures, the dimensions are again expressed as numbers in brackets (representing inches) over numbers without brackets (representing millimeters), and dimensions associated with a radius of curvature are preceded by the letter “R.” In addition, the diagram shown in  FIG. 6E  represents the cross-section of the prosthesis  600  along line A-A in  FIG. 6D , and the diagram shown in  FIG. 6G  represents the cross-section of the prosthesis  600  along line B-B in  FIG. 6F . Again, the prosthesis  600  may or may not be hollow within the undivided portion of the prosthesis  600  near the end  602  and may or may not be filled with a liquid, gel, or other material. 
         [0090]    As shown below, the prosthesis  600  can include an insert permanently or removably placed between or around the multiple portions  606   a - 606   b  of the end  604  of the prosthesis  600 . The insert may generally help to stabilize the prosthesis  600  (in addition to the stabilization already provided by the wider ends). 
         [0091]      FIGS. 7A through 7G  illustrate a seventh example scleral prosthesis  700  in accordance with this disclosure. The embodiment of the scleral prosthesis  700  shown in  FIGS. 7A through 7G  is for illustration only. Other embodiments of the scleral prosthesis  700  could be used without departing from the scope of this disclosure. 
         [0092]    As shown in  FIG. 7A , the scleral prosthesis  700  has two opposing ends  702 - 704 . Once again, in this example, only one end  704  of the prosthesis  700  is split or divided into multiple portions  706   a - 706   b  (although both could be). As opposed to prior prostheses, as shown in  FIG. 7B , the prosthesis  700  does not have a symmetrical cross-section. Instead, the prosthesis  700  has one side  711  that is relatively flat along the entire length of the prosthesis  700 . Here, the ends  702 - 704  have sides that are aligned with each other along the side  711  of the prosthesis  700 . Also, each of the ends  702 - 704  includes a single portion  708 - 710 , respectively, that is hook-shaped. As a result, both ends  702 - 704  are still wider than the middle portion of the prosthesis  700  and help stabilize the prosthesis  700 , but the ends  702 - 704  may not be as wide as prior prostheses. 
         [0093]    As with the prostheses  500  and  600 , the prosthesis  700  includes ridges  712  along the inner sides of the portions  706   a - 706   b . The ridges  712  generally travel lengthwise along the portions  706   a - 706   b  of the prosthesis  700  and may or may not be linked together. 
         [0094]    The prosthesis  700  could have the dimensions shown in  FIGS. 7B through 7G . These dimensions are for illustration only. The diagram shown in  FIG. 7E  represents the cross-section of the prosthesis  700  along line A-A in  FIG. 7D , and the diagram shown in  FIG. 7G  represents the cross-section of the prosthesis  700  along line B-B in  FIG. 7F . Also, the prosthesis  700  may or may not be hollow within the undivided portion of the prosthesis  700  near the end  702  and may or may not be filled with a liquid, gel, or other material. As explained below, the prosthesis  700  may include an insert permanently or removably placed between or around the multiple portions  706   a - 706   b  of the end  704  of the prosthesis  700 . The insert may generally help to stabilize the prosthesis  700  (in addition to the stabilization already provided by the wider ends). 
         [0095]    Although  FIGS. 1A through 7G  illustrate various examples of scleral prostheses, various changes may be made to  FIGS. 1A through 7G . For example, the sizes, shapes, and dimensions of the features of the scleral prostheses are for illustration only and can be altered in any suitable manner. Also, various features shown and described with respect to one of the scleral prostheses could be used with other scleral prostheses. As a particular example, the insert  408  of the prosthesis  400  could be used with any other suitable scleral prosthesis. As another particular example, a difference between the prostheses shown in  FIGS. 3A-3F  and the prostheses shown in  FIGS. 5A-7G  is that (when looking from an end viewpoint) the top edges of the ends have been shaved in  FIGS. 5A-7G  so that they slope downwards from top to bottom at about a 45° angle. This same feature could be used with any other prosthesis. 
         [0096]      FIGS. 8A through 8F  illustrate an example insertion of a scleral prosthesis into a patient&#39;s eye in accordance with this disclosure. The example insertion of the scleral prosthesis shown in  FIGS. 8A through 8F  is for illustration only. Other techniques could be used to insert a scleral prosthesis into a patient&#39;s eye without departing from the scope of this disclosure. 
         [0097]    As shown in  FIG. 8A , a prosthesis  800  is being implanted into a scleral tunnel  802  in a patient&#39;s eye. The prosthesis  800  could represent any suitable prosthesis, such as one of the prostheses discussed above or any other suitable prosthesis. In this example, the prosthesis  800  is inserted into a threader tube  804 , which is used to compress or push together the split or divided portions of the prosthesis  800  for insertion into the scleral tunnel  802 . The prosthesis  800  is pulled into the scleral tunnel  802  by the threader tube  804  and, optionally, a suture  806  that has been threaded through the scleral tunnel  802 . The end of the suture  806  in this example includes two loops that are placed through the threader tube  804  and connected to one end of the prosthesis  800 . In this example, the loops of the suture  806  loop around the cylindrical or triangular areas at one end of the prosthesis  800 . 
         [0098]    As shown in  FIGS. 8A and 8B , one end of the prosthesis  800  is connected to the suture  806  and can be inserted into the threader tube  804 . As shown in  FIGS. 8C and 8D , the threader tube  804  and the suture  806  can then be pulled so that the prosthesis  800  is pulled into the scleral tunnel  802 . In some embodiments, the prosthesis  800  is both pulled into the scleral tunnel  802  (such as by using the threader tube  804  and/or the suture  806 ) and pushed into the scleral tunnel  802  (such as by using an instrument held by a surgeon). As shown in  FIG. 8E , once the prosthesis  800  is implanted within the scleral tunnel  802 , the threader tube  804  can be pulled off the prosthesis  800 , and the suture  806  can be removed from the prosthesis  800 . This leaves the prosthesis  800  in the scleral tunnel  802  as shown in  FIG. 8F . 
         [0099]    Although  FIGS. 8A through 8F  illustrate one example of an insertion of a scleral prosthesis into a patient&#39;s eye, various changes may be made to  FIGS. 8A through 8F . For example, the threader tube  804  could have any suitable size or shape. Also, the suture  806  could be attached or coupled to the prosthesis  800  in any suitable manner. In addition, the suture  806  need not be used with the threader tube  804  to implant the prosthesis  800 . In particular embodiments, the prosthesis  800  could be pulled into the scleral tunnel  802  using only the threader tube  804 . 
         [0100]      FIGS. 9A through 9C  illustrate an example threader tube  900  used to insert a scleral prosthesis into a patient&#39;s eye in accordance with this disclosure. The embodiment of the threader tube  900  shown in  FIGS. 9A through 9C  is for illustration only. Other embodiments of the threader tube  900  could be used without departing from the scope of this disclosure. 
         [0101]    In this example, the threader tube  900  includes a wider upper portion  902 , a tapered portion  904 , and a narrower lower portion  906 . The lower portion  906  in this example includes an angled end  908 . The threader tube  900  could be formed from any suitable material(s), such as heat-shrink tubing formed from TEFLON PTFE (polytetrafluoroethylene). Also, the threader tube  900  could have any suitable shape that allows the threader tube  900  to be pulled through a scleral tunnel. For example, the threader tube  900  could have an overall length of 3.0 cm (±0.5 cm). The upper portion  902  could have a length of 1.0 cm (±0.2 cm), an internal diameter of 1.0 mm, and a minimum wall thickness of 0.08 mm. The lower portion  906  could have an internal diameter of 0.5 mm and a recovered minimum wall thickness of 0.12 mm. In addition, the end  908  of the lower portion  906  could have an angle of 30°. 
         [0102]    Optionally, a suture  910  can be placed through the threader tube  900 , and a rod  912  can be inserted into the lower portion  906  of the threader tube  900 . The illustration in  FIG. 9C  represents the cross-section of the threader tube  900  along the lower portion  906  of the threader tube  900 . The suture  910  travels through the threader tube  900 , loops around a scleral prosthesis  914 , and returns through the threader tube  900 . The suture  910  in this example loops around the central body of the prosthesis  914  (as opposed to looping over portions of the closer end of the prosthesis as shown in  FIGS. 8A through 8F ). The suture  910  represents any suitable suture made of any suitable material(s), such as 6-0 NYLON or PROLENE sutures having a 0.1 mm diameter. 
         [0103]    The rod  912  in this example includes a tapered and rounded end that can be inserted through a scleral tunnel ahead of the lower portion  906  of the threader tube  900 . The rod  912  can be used to facilitate insertion of the threader tube  900  into a scleral tunnel of a patient&#39;s eye. For example, the rod  912  may help the scleral tunnel to open and obtain a larger size before the lower portion  906  of the threader tube  900  is inserted into the scleral tunnel. The rod  912  could be formed from any suitable material(s) and can have any suitable size or shape, such as a cigar-shaped rod having a maximum diameter of 0.3 mm. Also, both ends of the rod  912  could, but need not, have the shape shown in  FIG. 9B . 
         [0104]    Although  FIGS. 9A through 9C  illustrate one example of a threader tube  900  used to insert a scleral prosthesis into a patient&#39;s eye, various changes may be made to  FIGS. 9A through 9C . For example, the threader tube  900  and rod  912  could have any suitable size or shape. Also, the suture  910  need not loop around the central body of the prosthesis  914  and could loop around or be attached to or associated with the prosthesis  914  in any suitable manner, such as by being looped around the closer end of the prosthesis  914 . Further, the suture  910  and/or the rod  912  need not be used along with the threader tube  900  to insert a scleral prosthesis into a scleral tunnel. 
         [0105]      FIGS. 10A and 10B  illustrate an example surgical blade  1000  used to create a scleral tunnel for receiving a scleral prosthesis in accordance with this disclosure. The embodiment of the surgical blade  1000  shown in  FIGS. 10A and 10B  is for illustration only. Other embodiments of the surgical blade  1000  could be used without departing from the scope of this disclosure. 
         [0106]    In this example, the surgical blade  1000  is used to automatically feed a suture through a scleral tunnel. The suture could then be used to pull a prosthesis into the scleral tunnel, such as is shown in  FIGS. 8A through 8F and 9A through 9C . However, as noted above, the use of a suture to pull a prosthesis into a scleral tunnel is not required, and the surgical blade  1000  could be modified to simply form a scleral tunnel without pulling a suture through the tunnel. 
         [0107]    As shown in  FIGS. 10A and 10B , the surgical blade  1000  includes a central portion  1002 , a curved cutting blade  1004 , and a connecting segment  1006 . The central portion  1002  is connected to a surgical tool and can be rotated in multiple directions to move the cutting blade  1004  into and out of the scleral tissue of a patient&#39;s eye. The connecting segment  1006  couples the central portion  1002  to the cutting blade  1004 , helping to translate rotation of the central portion  1002  into movement of the cutting blade  1004 . 
         [0108]    In this example, the cutting blade  1004  includes a notch  1008 . After the cutting blade  1004  is rotated into the scleral tissue of a patient&#39;s eye (and before it is rotated out of the scleral tissue), a suture  1010  can be placed in the notch  1008 . In some embodiments, the suture  1010  could have multiple loops at its end, and the loops may be placed in the notch  1008 . In other embodiments, the suture  1010  itself is placed within the notch  1008 . The suture  1010  could be loaded into the notch  1008  in any suitable manner, such as automatically or manually. The cutting blade  1004  is then rotated out of the patient&#39;s scleral tissue, pulling the suture  1010  with it. This allows the suture  1010  to be pulled through the scleral tunnel in a patient&#39;s eye at the time that the scleral tunnel is formed. The suture  1010  also helps to mark the location of the scleral tunnel, allowing a surgeon or other personnel to quickly locate the scleral tunnel in the patient&#39;s eye after the surgical blade  1000  is removed. 
         [0109]    Although  FIGS. 10A and 10B  illustrate one example of a surgical blade  1000  used to create a scleral tunnel for receiving a scleral prosthesis, various changes may be made to  FIGS. 10A and 10B . For example, the surgical blade  1000  need not include a notch  1008 , and the suture  1010  could be inserted through a scleral tunnel after the tunnel is formed. Also, as noted above, the suture  1010  could be omitted from the surgical procedure. 
         [0110]      FIGS. 11A through 11D  illustrate an eighth example scleral prosthesis  1100  in accordance with this disclosure. The embodiment of the scleral prosthesis  1100  shown in  FIGS. 11A through 11D  is for illustration only. Other embodiments of the scleral prosthesis  1100  could be used without departing from the scope of this disclosure. 
         [0111]    In this example, the scleral prosthesis  1100  changes shape after being implanted into a scleral tunnel. For example, the prosthesis  1100  could be formed from a shape-memory metal or other material that changes shape when exposed to certain temperatures or temperature ranges, such as a nickel titanium alloy or Nitinol. In this example, the prosthesis  1100  before implantation may have the shape shown in  FIG. 11A . Here, the prosthesis  1100  includes a generally flat central portion  1102  and two generally flat end portions  1104 - 1106 . Each of the end portions  1104 - 1106  includes two separated sections  1108 , which in this example are angled towards one another. 
         [0112]    Once inserted into a scleral tunnel, the temperature of the patient&#39;s scleral tissue may cause the prosthesis  1100  to assume the shape shown in  FIG. 11B . The central portion  1102  of the prosthesis  1100  is now arched or curved, and the sections  1108  of each end portion  1104 - 1106  angle away from one other. Also, the end portions  1104 - 1106  may be generally curved, while the tips of the end portions  1104 - 1106  are flatter to form splayed feet that provide support for the prosthesis  1100 . 
         [0113]    The prosthesis  1100  could be implanted into a patient&#39;s eye in any suitable manner. For example, the scleral prosthesis  1100  could be inserted into a scleral tunnel after a surgical blade has been used to form the scleral tunnel. 
         [0114]    In other embodiments, as shown in  FIG. 11C , the prosthesis  1100  could be placed within a sheath  1152  having an integrated blade  1154 . The integrated blade  1154  can be used to form a scleral tunnel in a patient&#39;s eye while the prosthesis  1100  is being inserted into the scleral tissue. For example, as shown in  FIG. 11D , a vacuum pot  1170  can be inserted onto a patient&#39;s eye, and vacuum forces could be used to pull up on the patient&#39;s scleral  1172  and conjunctiva  1174 . At this point, an incision could be formed in the patient&#39;s eye, such as an incision at location  1176 . This could include inserting the prosthesis  1100  into the patient&#39;s eye at the location  1176 , using the blade  1154  to cut into and form an incision through the patient&#39;s eye at that location. By pulling up on the patient&#39;s sclera  1172  before the incision is formed, a straight incision rather than a curved incision could be used to form a scleral tunnel. Although the incision is shown as occurring outside of the vacuum pot  1170 , the vacuum pot  1170  could include a mechanism for forming an incision inside the vacuum pot  1170 . Once implanted, the sheath  1152  could be opened and pulled through the scleral tunnel while the prosthesis  1100  is maintained in place (such as by a surgeon using a gripping tool to hold the prosthesis  1100  in place). However, the prosthesis  1100  could be inserted in any other suitable manner, with or without using a sheathe, integrated blade, or vacuum pot. 
         [0115]    In particular embodiments, the prosthesis  1100  may be malleable and caused to assume the shape shown in  FIG. 11A  at lower temperatures (in a “martensite” phase), such as temperatures below 60° F. At temperatures above 60° F. (in an “austenite” phase), the prosthesis  1100  may assume the arched shape shown in  FIG. 11B . The flatter shape of the prosthesis  1100  shown in  FIG. 11A  may help to reduce the profile of the prosthesis  1100  during implantation, which may reduce the size of an incision needed in the scleral tissue of a patient&#39;s eye. As a particular example, the prosthesis  1100  in  FIG. 11A  could have an arched height of 250 microns, and the prosthesis  1100  in  FIG. 11B  could have an arched height of 900 microns. Also, because the prosthesis  1100  in  FIG. 11A  is generally flat, a straight incision could be used to form a scleral tunnel instead of a curved incision, reducing the complexity of forming the incision. 
         [0116]    Although  FIGS. 11A through 11D  illustrate an eighth example scleral prosthesis  1100 , various changes may be made to  FIGS. 11A through 11D . For example, the prosthesis  1100  could have any suitable size or shape before and after implantation. As a particular example, while shown as including separated sections  1108  at its ends  1104 - 1106  in  FIG. 11A , each end  1104 - 1106  of the prosthesis  1100  could be fully integrated, and each end  1104 - 1106  may branch into multiple sections  1108  only after implantation. 
         [0117]      FIGS. 12A through 14B  illustrate additional example prostheses having inserts placed between portions or “legs” of one end of each of these prostheses.  FIGS. 12A and 12B  illustrate a ninth example scleral prosthesis  1200  in accordance with this disclosure. The embodiment of the scleral prosthesis  1200  shown in  FIGS. 12A and 12B  is for illustration only. Other embodiments of the scleral prosthesis  1200  could be used without departing from the scope of this disclosure. 
         [0118]    In this example, the scleral prosthesis  1200  is configured to receive an insert  1202 . The prosthesis  1200  includes a textured bottom surface  1204 , and the insert  1202  includes a textured bottom surface  1206  (although this feature could be omitted). Also, the interior sides of the legs of the prosthesis  1200  have “male” ridges  1208 , and the insert  1202  has “female” slots  1210  that guide the insert  1202  smoothly between the legs of the prosthesis  1200  (after the prosthesis  1200  itself has been inserted in a scleral tunnel). 
         [0119]    In addition, the insert  1202  includes a slightly wider circular “male” area  1212  at the interior end of the insert  1202 , which can be inserted into a corresponding circular “female” expansion  1214  on the prosthesis  1200  itself. As the insert  1202  approaches the end of its travel into the prosthesis  1200 , the area  1212  can be snapped into the expansion  1214 , which helps to ensure that the insert  1202  does not fall out of the prosthesis  1200  after implantation. 
         [0120]    The insert  1212  can be permanently or removably placed between the legs of the prosthesis  1200 . For example, the insert  1212  could be placed between the legs of the prosthesis  1200  after the prosthesis  1200  has been implanted in a scleral tunnel in a patient&#39;s eye. The insert  1212  could later be removed, such as to facilitate removal of the prosthesis  1200  from the scleral tunnel. 
         [0121]    The insert  1212  may generally help to stabilize the prosthesis  1200  (in addition to the stabilization already provided by its wider ends). For example, the insert  1212  could help to prevent the legs of the prosthesis  1200  from separating excessively, which could pull the opposite end through the scleral tunnel and force the prosthesis  1200  out of the tunnel completely. The insert  1212  could also function to reduce or prevent rotation of the prosthesis  1200  within the scleral tunnel. For instance, the insert  1212  may help to ensure that the legs of the prosthesis  1200  form an end having a desired width, so the end remains wide enough to prevent the prosthesis  1200  from rolling over once implanted in the scleral tunnel. Moreover, the insert  1212  can be inserted into or around the prosthesis  1200  only after the prosthesis  1200  has been implanted, which enables the legs of the prosthesis  1200  to be pushed together during implantation but prevents the legs from coming together after implantation. 
         [0122]      FIGS. 13A through 13D  illustrate a tenth example scleral prosthesis  1300 ,  1350  in accordance with this disclosure. The embodiments of the scleral prostheses  1300 ,  1350  shown in  FIGS. 13A through 13D  are for illustration only. Other embodiments of the scleral prostheses  1300 ,  1350  could be used without departing from the scope of this disclosure. 
         [0123]    As shown in  FIGS. 13A and 13B , an insert  1302  can be placed between the legs of the prosthesis  1300 . Similarly, as shown in  FIGS. 13C and 13D , an insert  1352  can be placed between the legs of the prosthesis  1350 . The inserts  1302  and  1352  can function in the same or similar manner as the insert  1202  described above. Moreover, the same mechanisms (male ridges, female slots, male areas, and female expansions) could be used with the prostheses  1300 ,  1350  and inserts  1302 ,  1352 . 
         [0124]      FIGS. 14A and 14B  illustrate an eleventh example scleral prosthesis in accordance with this disclosure. The embodiment of the scleral prosthesis  1400  shown in  FIGS. 14A and 14B  is for illustration only. Other embodiments of the scleral prosthesis  1400  could be used without departing from the scope of this disclosure. 
         [0125]    As shown in  FIGS. 14A and 14B , an insert  1402  can be placed between the legs of the prosthesis  1400 . The insert  1402  can function in the same or similar manner as the insert  1202  described above. Moreover, the same mechanisms (male ridges, female slots, male areas, and female expansions) could be used with the prosthesis  1400  and insert  1402 . 
         [0126]    In particular embodiments, the prostheses  1200 - 1400  shown in  FIGS. 12A through 14B  represents the same or similar prostheses described above in  FIGS. 5A through 7G . However, the inserts could be used with any other suitable prosthesis. 
         [0127]    Although  FIGS. 12A through 14B  illustrate various examples of scleral prostheses having inserts, various changes may be made to  FIGS. 12A through 14B . For example, the sizes, shapes, and dimensions of the features of the scleral prostheses are for illustration only and can be altered in any suitable manner. Also, various features shown and described with respect to one of the scleral prostheses could be used with other scleral prostheses (including the prostheses shown in  FIGS. 1 through 7G ). 
         [0128]    In addition, in some embodiments, any of the scleral prostheses described above could be fabricated using at least one magnetic material. For example, the entire body of a scleral prosthesis could be formed from at least one biocompatible magnetic material, or the scleral prosthesis could be formed from at least one non-biocompatible magnetic material and then encased in a biocompatible cover or shell. Also, a portion of a scleral prosthesis could be formed from at least one magnetic material. For instance, when a scleral prosthesis includes an insert (such as is shown in  FIGS. 4A and 12A through 14B ), the body or the insert could be formed from at least one magnetic material, or both the body and the insert could be formed from the same magnetic material(s) or from different magnetic materials. In some cases, the body and the insert could be magnetically attracted to each other in order to help secure the insert to the body. This could be accomplished using at least one magnetic material in the body and at least one metal in the insert (or vice versa). This could also be done using magnetic materials that are attracted to one another in the body and the insert. 
         [0129]      FIG. 15  illustrates an example method  1500  for inserting a scleral prosthesis into a patient&#39;s eye in accordance with this disclosure. The method  1500  shown in  FIG. 15  is for illustration only. Other techniques could be used to insert a scleral prosthesis into a patient&#39;s eye without departing from the scope of this disclosure. 
         [0130]    A scleral tunnel is formed in a patient&#39;s eye and a suture is placed through the scleral tunnel at step  1502 . This could include, for example, using a tool with a curved cutting blade to form the scleral tunnel. This may also include pulling a suture through the scleral tunnel using the curved cutting blade. This may further include pulling a suture through the scleral tunnel after the curved cutting blade has completed the formation of the tunnel. 
         [0131]    The suture is looped around a scleral prosthesis at step  1504 . This could include, for example, placing loops at the end of a suture around one end of the scleral prosthesis (such as is done in  FIGS. 8A through 8F ). This could also include looping a suture around the central body portion of the scleral prosthesis (such as is done in  FIGS. 9A through 9C ). This step may also involve placing the suture through a threader tube. 
         [0132]    The scleral prosthesis is inserted into the threader tube at step  1506 . This could include, for example, inserting one end of the scleral prosthesis into the threader tube. Any suitable portion of the scleral prosthesis can be inserted into the threader tube, such as a portion that prevents premature ejection of the scleral prosthesis within the scleral tunnel. 
         [0133]    The threader tube is inserted into the scleral tunnel at step  1508 . This could include, for example, pushing the lower portion  906  of the threader tube into the scleral tunnel. This could also include pulling the threader tube into the scleral tunnel using the suture. This could further include using the rod  915  to open the scleral tunnel before the body of the threader tube is pulled into the scleral tunnel. The scleral prosthesis is pulled into the scleral tunnel at step  1510 . This could include, for example, pulling the scleral prosthesis into its proper position within the scleral tunnel using the threader tube and the suture. 
         [0134]    The scleral prosthesis is removed from the threader tube at step  1512 , and the threader tube and the suture are removed at step  1514 . This could include, for example, pulling the threader tube off the scleral prosthesis. This could also include pulling on one end of the suture to remove the suture from the scleral tunnel. 
         [0135]    If necessary or desired, an insert can be placed between or around portions of the implanted scleral prosthesis at step  1516 . This could include, for example, placing the insert between or around separated or divided portions of the scleral prosthesis to prevent rotation, flexing, ejection, or other movement by the scleral prosthesis. 
         [0136]    Although  FIG. 15  illustrates one example of a method  1500  for inserting a scleral prosthesis into a patient&#39;s eye, various changes may be made to  FIG. 15 . For example, any other suitable technique could be used to place a suture through the scleral tunnel. Also, any other suitable technique could be used to pull or push the scleral prosthesis into the scleral tunnel, including techniques omitting the use of a suture or rod. 
         [0137]    It may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and/or. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. 
         [0138]    While this disclosure has described certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure, as defined by the following claims.