Abstract:
A device and method is disclosed for treating macular degeneration, an affliction of the eye. An incision is made in the scleral region of the eye and an optical prosthesis for diverging incoming light is inserted and positioned within the vitreous humor proximate to the retina of the eye. The optical prosthesis may be a lens having one or more concave faces. Alternately, the optical prosthesis may be an assembly including a number of optical components. The optical prosthesis intercepts light directed at the macular region of the retina and spreads the light over a larger region of the retina. The optical prosthesis may be anchored or stabilized in a variety of ways prior to closing the incision.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to the field of optical prosthetic devices, or implants, and more particularly to an implantable optical device and method for ameliorating the effects of macular degeneration to make it easier for one suffering from the affliction to see.  
         BACKGROUND OF THE INVENTION  
         [0002]    Advances in medical technology, ever more widely available, along with increasingly safer living environments and healthier lifestyle practices, have led to the increased life expectancy we enjoy today. People, especially those living in developed countries, can expect on average to live lives that are much longer then those of their ancestors of only a few generations ago. Although this phenomenon is generally considered a positive one, it does mean that an ever-larger segment of the population has to deal with the many problems associated with old age. Some of these problems are modest and represent largely an irritation, such as a slow decline of muscular strength and speed, incremental weight gain, the development of wrinkles, and a deterioration of skin tone. Other age-related problems are more significant, however, and some age-related illnesses can be debilitating.  
           [0003]    Many, if not most adults also experience a decline in the quality of their eyesight as they age, and often need to resort to reading glasses that they did not need when they were younger. Vision problems usually follow the pattern of other age-related ailments, that is, a slow but steady decline with consequences that can range from mild to severe. Not unexpectedly there is not one, but numerous medical conditions that can lead to a loss of visual acuity, each with their own etiology, or cause.  
           [0004]    The present invention is a way to try and counter at least some effects of one such condition, which is known as macular degeneration. Macular degeneration stems, in general, from the destruction of light-sensitive cells in the macula, an area of the retina important for seeing detail. The more cells that are lost, the more severe the effects of the condition. A brief review of the anatomy of the eye, beginning with a description of FIG. 1, will be helpful to more fully understand the phenomenon of macular degeneration, as well as the presently proposed method and device for attempting to lessen its adverse effects.  
           [0005]    [0005]FIG. 1 is an illustration of the outwardly visible portion of a typical eye  100 , in this case a human eye. Behind the transparent cornea  105  can be seen the pupil  110 , which appears as a black circle of varying size at the center of the eye, and the iris  115 , the colored area surrounding the pupil. The so-called “color” of a person&#39;s eye is the color of the pigments contained in the iris, which typically range from blue to dark brown. The “white of the eye” surrounding the iris  115  is the sclera  120 . Sclera  120  is a tough, protective layer that helps to maintain the shape of the eye  100 . The eyelids  102  above and below eye  100  are not actually part of the eye itself, but rather protective skin flaps that can be extended and retracted to cover and uncover the eye, selectively allowing light to enter and spreading needed moisture on its surface.  
           [0006]    [0006]FIG. 2 is a cross-sectional view of the eye  100  of FIG. 1 taken along section line A-A. In this view the relationship of the cornea  105  to the pupil  110 , iris  115 , and sclera  120  is more clearly illustrated. The transparent cornea  105  allows light to enter the eye  100 . Light entering through the cornea  105  also passes through the pupil  110 , which is not actually a structure but rather an opening formed by the muscles of the iris  115 . Iris  115  includes two major sets of muscles (not separately shown or enumerated), namely, the pupillary dilator and the pupillary sphincter for, respectively, dilating and constricting the pupil  110  to control the amount of light entering the eye&#39;s interior.  
           [0007]    Light rays allowed to pass through the pupil  110  are received at the crystalline lens  125 . The lens  125  is generally composed of a set of regularly oriented protein fibers enclosed in a clear capsule. Optically, crystalline lens  125  is a convex lens that focuses the light entering the eye. Lens  125  is sufficiently flexible to allow its shape to be manipulated by the muscles of the ciliary body  130 . The muscles of the ciliary body  130  act on the lens  125  through a network of fibers known as zonules  145 . The manipulation of the lens  125  allows the eye  100  to focus on objects that are nearer or farther away. The space between the cornea  105  and the lens  125  is divided by the iris into an anterior chamber  135  and a posterior chamber  130 , which are filled with a normally clear watery substance known as aqueous humor.  
           [0008]    Behind the lens  125  is a main eye chamber  170  filled with vitreous humor, a clear gel-like material. Light entering the eye&#39;s interior passes through the vitreous humor on its way to the posterior portion of the eye  100 , which contains several important areas that will now be explained.  
           [0009]    At the back of the eye  100  lies the retina  150 , a seven-layer structure that transduces incoming light rays, converting them from images to neural signals for sending to the brain. Photoreceptors called rods and cones (not shown) are excited when light entering the eye reaches them. A neural signal is transmitted via bipolar cells to ganglion cells (also not shown) that transmit the neural signals created by the rods and cones to the brain. The axons of the ganglion cells from throughout the retina gather at the optic disk  180  and leave the eye  100  through the optic nerve  175 .  
           [0010]    The photoreceptors are present in greater density in a specialized area called the macula  155 , which is located approximately in the center of the retina  150 , below and to one side of the optic disk  180 . The macula  155  contains in particular a high concentration of cones, the photoreceptors that are sensitive to color, and that are required for sharp, detailed vision. Near the center of the macula  155  is a depression called the fovea  160 , where the photoreceptors are exclusively cones.  
           [0011]    [0011]FIG. 3 is a cross-sectional view of the macular region  155  of the retina  150 . Note that for purposes of this illustration the macula  155  in general, and the fovea  160  in particular, are taken to be circular in shape and symmetrical about any section line taken along a diameter, thus no particular section line is delineated in FIG. 2. While this may be substantially if not precisely accurate, it may be taken as true for purposes of this disclosure. In roughly the center of macula  155  the foveal rim  166 , a slightly raised (that is, thicker) area of the macula surrounds the foveal slope  164  leading down to the foveal pit  162 . The foveal pit  162  is composed of deeply packed cone cells and is, not unexpectedly, the area of sharpest vision of the eye.  
           [0012]    The macula  155  generally is therefore a very important region because it allows eye  100  to detect finer detail than the remainder of the retina  150 . For this reason, incoming light rays are primarily focused toward the macula  155  by the crystalline lens  125 . (The remainder of the retina  150  provides for peripheral vision, motion vision, and night vision.) Note that the common problems of near- and far-sightedness occur when the focal point of the light rays formed by the crystalline lens  125  falls in front of or behind, respectively, the (curved) plane of the retina  150 . These are often corrected by external devices such as glasses or contact lenses, which act to readjust the location of the focal point.  
           [0013]    Unfortunately, age-related macular degeneration can cause an actual loss of photo-receptors in the important macular area, which reduces the subject&#39;s ability to see in a way not easily correctable using external lenses. There may be several contributors to this loss, but the exact etiology that causes some or many of the cone shaped photoreceptors to die is unknown. Although treatments exist that may slow the process of macular degeneration, there is no way to repair the damage that has already occurred. Subjects afflicted with macular degeneration therefore suffer at least some permanent loss of visual acuity.  
           [0014]    Adaptive adjustments can be made. If a subject looks to the side of an object they wish to view, they may be able to perceive the object with their peripheral vision, which utilizes unaffected rod and cone cells (the photo-receptors) outside of the macular area. However, the sharpness of the image is decreased. In general this practice takes some getting used to, and can be disconcerting where the object to be viewed is in fact a person. The viewed person may perceive that the macular-degeneration sufferer is not looking at them at all, even though that is precisely what the person with less-than-perfect vision is attempting to do.  
           [0015]    It would be desirable for these reasons if a device and method existed that would allow a surgeon to treat macular degeneration using an implanted optical prosthesis that would permit a macular-degeneration sufferer to view objects by “looking” at them more directly and to increase their visual acuity. Accordingly, a need exists in the art for an appropriately constructed device, and a method of implanting it as well. The present invention provides just such a solution.  
         SUMMARY OF THE INVENTION  
         [0016]    The present invention is directed to a technique for using an intraocular device implanted in the vitreous humor region (main chamber) of the eye, proximate to the retina, to alter the path of incoming light in order to enhance the vision of an eye afflicted with macular degeneration. In one aspect, the present invention is an optical prosthesis such as a lens for implantation in the eye. In one embodiment, the device includes a lens for altering the path of light that would otherwise be directed at (or near) the foveal area of the retina. The lens has two faces, one or both of which may be concave in order to achieve a light-diverging effect. In use the device is placed proximate to the retina near the region of the macula. The device may include a frame to assist in retaining the lens properly in position. The device may also be a compound lens system rather than a single-lens device.  
           [0017]    In another aspect, the present invention is a method of treating an eye afflicted with macular degeneration, including the steps of making an incision in the scleral portion of the eye, inserting the optical prosthesis, positioning the optical prosthesis proximate the macular area of the eye, and closing the incision. The method of the present invention may also include the steps of preparing a site within the vitreous humor for placement of the optical prosthesis, and of using a retaining means to retain the optical prosthesis in place.  
           [0018]    Accordingly, it is an object of the present invention to provide a treatment for macular degeneration by implanting proximate to the retina of an eye a light-diverging optical device.  
           [0019]    It is another object of the present invention to provide a method of treating macular degeneration by using an implant positioned at or near the retina.  
           [0020]    Additional objects of the present invention will become apparent from the description of the invention that follows.  
           [0021]    The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the Detailed Description of the Invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject matter of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.  
           [0022]    Before undertaking the Detailed Description of the Invention, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The terms “include” and “comprise,” and 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, to bound to or with, have, have a property of, or the like; and the term “controller,” “processor,” or “apparatus” means any device, system or part thereof that controls at least one operation. Such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document. Those of ordinary skill should understand that in many instances (if not in most instances), such definitions apply to prior uses, as well as to future uses, of such defined words and phrases.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    [0023]FIG. 1 shows a frontal view of the ordinarily visible portions of an eye, in this case a human eye;  
         [0024]    [0024]FIG. 2 is a cross-sectional view of the eye of FIG. 1, taken approximately along the section line A-A;  
         [0025]    [0025]FIG. 3 is a cross-sectional view illustrating specifically the macular region of the eye of FIGS. 1 and 2;  
         [0026]    [0026]FIG. 4 a  is a frontal view of an exemplary optical prosthesis according to one embodiment of the present invention; FIG. 4 b  is a lateral cross-sectional view of the optical prosthesis of FIG. 4 a;    
         [0027]    [0027]FIG. 5 a  is a frontal view of an exemplary optical prosthesis according to another embodiment of the present invention; FIG. 5 b  is a lateral cross-sectional view of the optical prosthesis of FIG. 5 a;    
         [0028]    [0028]FIG. 6 is a cross-sectional view of an eye into which the optical prosthesis of FIGS. 4 a  and  4   b  has been implanted;  
         [0029]    [0029]FIG. 7 a  is a frontal view of an exemplary optical prosthesis according to another embodiment of the present invention; FIG. 7 b  is a lateral cross-sectional view of the optical prosthesis of FIG. 7 a;    
         [0030]    [0030]FIG. 8 is a cross-sectional view of an eye into which the optical prosthesis of FIGS. 7 a  and  7   b  has been implanted;  
         [0031]    [0031]FIG. 9 is a flow chart illustrating an advantageous embodiment of a method for treating macular degeneration according to an embodiment of the present invention; and  
         [0032]    [0032]FIG. 10 is a cross-sectional view of an eye into which an optical prosthesis has been implanted and secured according to an embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]    [0033]FIGS. 4 a  through  10 , discussed below, and the various embodiments used to describe this principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the present invention may be implemented in any suitably arranged optical device that is implanted proximate to the retina  150 . Note that as used herein, “proximate to the retina” refers to a location within the vitreous humor, and preferably closer to the retina than to the crystalline lens. In some applications, the optical prosthesis will touch, or nearly touch the retina, though this contact is not required.  
         [0034]    [0034]FIGS. 4 a  and  4   b  illustrate an optical prosthesis  400  according to an exemplary embodiment of the present invention. In this embodiment, optical prosthesis  400  is a lens  410  surrounded by a frame  450 . As in each embodiment, the purpose of the optical prosthesis is to intercept and diverge light as it passes through the optical prosthesis on its way from the crystalline lens  125  of the eye to the retina  150 . FIG. 4 b  is a lateral cross-sectional view of the optical prosthesis  400 . In this view it can be seen that the lens  410  has a concave outer surface  420  and concave inner surface  415 . A lens so configured will cause light passing through it to diverge, meaning that an image carried by light passing through the lens will impact a larger area of whatever surface it eventually strikes. Note that either the inner surface or the outer surface of lens  410  (or both) may also be convex, or they may be flat (that is, neither convex nor concave). In this application, of course, the surface will be the retina  150 . Causing the image to impact a larger retinal area, preferably including portions of the retina  150  outside of the macula  155 , is intended to cause the excitation of many additional photoreceptors, including those that have not been destroyed by macular degeneration. Although the resultant perceived image may not be as clear as it would be in an unafflicted (and unaided) eye, it may represent a great improvement over that obtainable without the optical prosthesis.  
         [0035]    Lens  410  may be made of, for example, polymethylmethacrylate (PMMA), silicone, polysulfone, glass, or hydrophilic or hydrophobic acrylic materials. Other biocompatible materials may be used as well. In one embodiment, the lens  410  may be a GRIN lens. A GRIN lens is a lens that has a gradient refractive index such that the optical power of the lens varies according to the location at which the light enters the lens. Lens  410  may also be a Fresnel lens. A Fresnel lens is one cut in a series of steps, or formed of a series of prisms more or less concentrically arranged, such that entering light is concentrated and collimated. Similarly, lens  410  may be constructed of one or more prisms for refracting and reflecting the incoming light before it reaches the retina. The type of lens used will, of course, depend on the effect that is sought to be achieved for a particular patient.  
         [0036]    In order to further tune the effect produced by the optical device, it or any portion of it may be made of a light-polarizing material. The polarized material may help to control the unnecessary or unwanted dispersion of the light passing through it. The device may also be colored, that is, composed in whole or in part of a material that filters out certain portions of the visible electromagnetic spectrum. In yet another embodiment, the lens  410  is coated with a material for altering, when desired, its optical properties or light-diverging ability. For example, porous silicon or silicon nitrate may be used for this purpose.  
         [0037]    The different types of lens materials, treatment, or configuration affect, among other things, its index of refraction. In accordance with various embodiments of the present invention this index may be higher, lower, or equal to the index of refraction of the vitreous humor, the retina, or either or both of them. Where multiple lenses are used, of course, their indices of refraction may vary. Any other material contained by the optical device may, of course, have the same or a different index of refraction.  
         [0038]    [0038]FIG. 4 a  is a frontal view of optical prosthesis  400 , illustrating that the lens  410  from this perspective is generally circular in shape and entirely surrounded at its peripheral circumference by frame  450 . (A circular shape is expected to be desirable in many situations but it is not required.) Frame  450 , although optional, may be advantageously employed in some cases. Frame  450  may be integrally formed with the lens  410 , or it may be a separately formed component. If separate, it may be attached in a variety of ways, including the use of an adhesive, or mechanical fasteners, or simply sized that it may be press fit.  
         [0039]    The frame  450  may have desirable optical characteristics as well, or may be designed to lie, when installed, in an unobtrusive area. The frame  450  may itself in some cases actually interfere somewhat with vision, but the device may be used nevertheless if the overall benefit outweighs this detriment. Note that the frame  450  need not be the same shape as the lens, nor must it be in contact with the lens continuously about an inner circumference (as shown in FIG. 4 a  and  4   b ). To serve as a frame, however, it must at some location or locations contact the lens, either directly or through some other intermediate member (not shown). In one alternative embodiment, the intermediate member may include a network of fibers suspending the lens in position. The lens may have separate members attached directly to it without any intermediate frame and, if so, these members may be used to support the lens. Of course, a net (not shown) could be used for anchoring the lens without a frame as well, for example, by fixing the net to the eye  100  in some way or by attaching it to air-fill capsules that would “float” to the top of the vitreous humor and in that way maintain the lens in a relatively (though of course not completely) stable position.  
         [0040]    The frame  450 , or an attached member, if present, may provide a convenient place to hold the optical prosthesis during insertion and positioning. It may also be used as an aid to proper positioning of the lens in relationship to the retina  150 . As light passed through optical prosthesis  400 , it is redirected in a diverging fashion, though it will need to pass some distance beyond the inner surface  415  of lens  410  if it is to spread out significantly. In the embodiment of FIGS. 4 a  and  4   b , note how the edge of frame extends beyond the shallowest portion of the concave inner surface  415 . When in place, this relationship may provide the desired spacing between the lens  410  and the retina  150 . Naturally, the relative inward extension of frame may be changed to match the individual circumstances.  
         [0041]    In addition, to the extent that the frame is designed to contact the retina itself, it may also be shaped to increase or reduce the actual contact area, as desired. It may also be formed to an appropriate size to, by its contact with the retina, tend to hold the optical prosthesis in place. Of course, however it is designed, its effect on the subject&#39;s overall vision ability should be taken into account.  
         [0042]    Where the optical device contacts the retina in such a manner that an enclosed area is created between the device and the retina, lowering the pressure within the enclosed area, relative to the surrounding vitreous humor, may also be used to help anchor the device in place. The pressure differential may be created by evacuating some of the fluid from the enclosed area during or after implantation, or by incorporating into the device a resilient member that can be deformed during implementation in such a way that a pressure differential is created as it attempts to return to its resting shape after removal of the deforming force. A frame comprising a silicone ring, for example, may seal adequately to prevent the differential pressure from equalizing, and may also serve as the resilient member that helps to create the anchoring pressure difference. Alternatively, the optical device is simply a diverging lens that is placed against the retina and is held in position by surface tension.  
         [0043]    [0043]FIGS. 5 a  and  5   b  illustrate an optical prosthesis  500  according to another exemplary embodiment of the present invention. FIG. 5 a  is a frontal view of the device, which in this embodiment includes a first lens  510  and a second lens  530 . Prostheses including more than one lens may be referred to as compound-lens prostheses, and the lenses themselves (in combination) as a compound lens system. In this embodiment, first lens  510  has a concave outer surface  520  and a concave inner surface  515 . Second lens  530  also has a concave outer surface  540  and a concave inner surface  515 , and is separated from first lens  510  by a distance d, a relationship fixed by frame  550 . Note that distance d is here shown for clarity to be relatively large, making the optical prosthesis  500  appear somewhat elongate. This configuration is not required, however, and in fact distance d may be quite small. Likewise, first lens  510  is not required to be smaller than second lens  530 , as is shown in FIG. 6, although the light passing through first lens  510  will be diverged and a larger second lens  530  may therefore be desirable. Finally, it is not necessary that both lenses be doubly concave in shape.  
         [0044]    The cavity  555  formed between the inner surface  515  of first lens  510  and the outer surface  540  of second lens  530  may be filled with air or with some other fluid, depending on the optical qualities desired (or on other considerations). The fluid may, for example, be a viscous fluid such as a gel. In one embodiment the fluid has an index of refraction lower than that of the vitreous humor. In that regard, note that the use of a fluid-filled cavity is not limited to compound lens systems. The lens itself may, for example, be made of a gel having an appropriate refractive index enclosed in a capsule or sac.  
         [0045]    In one embodiment (not shown), the gel or other fluid in the cavity may have a refractive index that can be altered by exposure to energy emitted from an energy source, for example, light energy from a laser. Other forms of light energy may be used as well, as may non-light energy from an electrical, magnetic, thermal, or ultra-sound source.  
         [0046]    Returning to the embodiment of FIGS. 5 a  and  5   b , cavity  555  may also be provided with one or more openings (not shown) in order to permit the free passage of the surrounding vitreous humor. Naturally, some compensation may have to be made for the volume displaced by optical prosthesis  500 , especially of a significant cavity  555  is not allowed to fill. In an alternate embodiment (also not shown), the first lens and the second lens are detachable from each other or from the frame so that they may be separately fitted into place, after which the components may or may not be fixed together. In yet another embodiment (not shown), the first and second lenses may be completely separate components that cooperate even though they are not in physical contact.  
         [0047]    [0047]FIG. 6 is a cross-sectional view of an eye into which has been implanted the optical prosthesis  400  of FIGS. 4 a  and  4   b . In this embodiment, it can be seen that Frame  450  extends posteriorly to maintain the lens  410  in a spaced relationship with retina  150 . In one embodiment, the optical prosthesis  400  is itself large enough to ensure that frame  450  does not significantly impact the retinal area at all, although in some cases retinal contact may be satisfactory. Light rays entering eye  100  through pupil  110  will tend to converge toward a focal point, which in a normally functioning eye would be in the region of the macula  155 . As light passes through the lens  410  of optical prosthesis  400 , however, the light rays are spread so as to impact retina  150  over a larger area. In this regard, note that the optical prosthesis must be oriented such that this advantageous effect is achieved. This does not mean, however, that any precise orientation is required, though in some cases it may be desirable.  
         [0048]    In this way, the wearer of the optical prosthesis  400  may look directly at an object, and still see it to some extent notwithstanding an existing macular degeneration condition. Note that the image perceived by the eye containing optical prosthesis  400  may not perceive the viewed object in the same way that it would have been perceived by a normally functioning eye. Although such a phenomenon would be of great advantage, the object of the present invention is to provide as good and as sharp a view as possible of an object, especially one located directly in front of the eye.  
         [0049]    [0049]FIGS. 7 a  and  7   b  illustrate an optical prosthesis  700  according to another embodiment of the present invention. FIG. 7 a  is a frontal view of the exemplary optical prosthesis  700 , and FIG. 7 b  is a lateral cross-sectional view. In this embodiment, optical prosthesis  700 , which includes lens  710  and frame  750 , also includes structural support members  760 . The support members may be directly attached to the lens without an intervening frame. The structural members, which are shown here to be symmetrically disposed about the optical prosthesis  700 , may be disposed asymmetrically as well. The function of the support members  760  is to contact the inner surface of the eye to assist in holding the optical prosthesis  700  in a fixed orientation, or at a fixed distance from the retina  150 , or both.  
         [0050]    In this regard, it may also be noted that optical prosthesis  700  may be sized so that its diameter, or alternately that of its lens (or framed lens), is substantially the same size as the macular area of the retina. By “same size” it is meant that the diameter as viewed from the pupil is substantially the same. Note that this dimension will sometimes for convenience be referred to as the “diameter” even if the device (or macula) is not exactly round in shape when viewed from this perspective.  
         [0051]    The support members  760  may either be placed against the inner surface of the eye  100 , or they may be fastened to it in some way, for example, by using an adhesive substance, a suture sewn into the sclera  120 , or even using mechanical fasteners such as tacks that partially or completely penetrate sclera  120 . Mechanical fasteners may be made of, for example, titanium, stainless steel, PMMA, or other biocompatible materials. Of course, a combination of fastening means may be used, as illustrated in FIG. 10. FIG. 10 is a cross-sectional view of an eye  100  into which an optical prosthesis  1000  has been implanted according to an embodiment of the present invention. As with embodiments that have been elsewhere described, the optical prostheses  700  and  1000  need not include a frame, although where the supporting members are present, they will preferably attach to the device in some fashion that does not materially affect the desired optical characteristics of the lens  710  (or  1010 ).  
         [0052]    Turning now to the embodiment of FIG. 10, note that as with some of the other embodiments described herein, optical prosthesis  1000  includes a lens  1010 , a frame  1050  and supporting members  1060 , all of which are in this illustration shown in cross-section. Note that as illustrated here, optical prosthesis  1000  is similar though not identical to the optical device  700  shown, for example, in FIG. 8.  
         [0053]    Unlike that device, however, optical prosthesis  1000  is anchored in place using a combination of anchoring means. In this embodiment, a plurality of tacks  1065  are passed through the supporting members  1060  and through the sclera  120 , holding optical prosthesis  1000  firmly in position. In addition, suture  1070  wrapped about supporting members  1060  is also passed through the sclera  120  and tied off, providing additional support. Finally, a net  1075  is formed of a plurality of filaments or fibers (not separately enumerated) that also help to hold optical prosthesis  1000  in place. In this embodiment, the fibers of net  1075  are attached to, but do not pass completely through the sclera  120 . Note that the embodiment of FIG. 10 is for illustration of various anchoring means, and it is not necessary that all such means are used in combination. Depending on the circumstances, the use of any one or all of them may be desirable. In addition, the use of such anchoring devices does not preclude the circumstance that the optical prosthesis  1000  may also be held in place by other means, such as pressure differential or surface tension. Note also that the use of terms such as “anchoring means”, “anchoring device”, or “held securely (or firmly) in place”, do not indicate that the implanted prosthesis must be completely free of movement in any direction. Such movement may be tolerable, and even in some circumstances desirable. Finally, it is here reiterated that the supporting members, such as supporting members  1060  shown in FIG. 10, as well as the frame  1050 , are not required elements for the optical prosthesis. The anchoring means described herein and illustrated, for example, in FIG. 10 may be used whether or not these elements are present. The net  1075 , for example, may be particularly advantageous when used with a “lens-only” optical prosthesis (not shown in the illustration).  
         [0054]    In yet another alternate embodiment (not shown), the supporting members are not disposed completely around the peripheral of the optical prosthesis, but rest against the eye  100  and help maintain the device&#39;s position in certain directions, with, for example, the frame  750  of FIG. 8 also resting against a different portion of the eye and providing additional stability. Note that there may be any number of supporting members.  
         [0055]    [0055]FIG. 8 is a cross-sectional view of an eye into which the optical prosthesis of FIGS. 7 a  and  7   b  has been implanted. As mentioned above, in this embodiment the peripheral portions of the supporting member  760  contact the inner surface of the eye  100 , helping to stabilize the optical prosthesis  700  in a fixed relationship with respect to the retina (and specifically, the macula).  
         [0056]    [0056]FIG. 9 is a flow chart illustrating a method  900  for treating macular degeneration of an eye according to one embodiment of the present invention. Note that as used herein, a “treatment” is an attempt to correct a known problem by a directed and purposeful action (or forbearance) from which some improvement is reasonable expected. In terms of this disclosure, however, and of the claims reciting the present invention, it is not meant to imply that any level of improvement must actually be realized. In this regard, it is noted that the claims are also intended to cover experimental use of the device and method even if in the experiment itself no improvement in sight is expected. Such would be the case, for example, in cadavers and in animals other than humans. For another example, a person with only one functional eye may agree to the implantation of an optical prosthesis in their non-functional eye in order to test their personal level of acceptance of the device before an attempt is made on the working eye. In these examples, the procedure is performed with no specific expectation of vision improvement, but the claims are nevertheless meant to cover such situations.  
         [0057]    Returning to FIG. 9, at Start it is assumed that the patient is prepared for surgery; stabilized and placed in a clean environment and in a convenient orientation, and sedated or anesthetized as necessary under the circumstances. At step  910 , a site for making an incision is exposed and chosen, and the eye itself is then stabilized (step  915 ). An incision of a size appropriate to the optical prosthesis being installed is made (step  920 ). The site for implantation is then confirmed and probed or prepared as necessary (step  925 ). The optical prosthesis can then be inserted and properly oriented (step  930 ). Once in place, any additional optical or structural components may be implanted (step  935 ), including members for stabilizing the optical prosthesis or attaching it to the eye. The location of the optical prosthesis is then reviewed (step  940 ) to ensure that it has been properly and securely placed. This may include an ophthalmic examination through the incision itself, through a separate incision created for the purpose, or a visual inspection made through the cornea  105 . An optical test (step not shown) may also be conducted at this time.  
         [0058]    In an alternate embodiment (also not shown), such an optical test may form an important part of the implantation procedure, with repeated placement and testing of a sequence of optical prostheses to find the one optimum for the eye and the subject being treated. As mentioned above, the optical prosthesis itself may include two or more components that may be detached from one another and interchangeable parts would permit the fitting and testing of a device with varying characteristics. A test procedure is developed to suit the particular eye, perhaps taking into account an assessment of the damaged area, and differently configured optical prostheses are tested to find the one producing the best test result.  
         [0059]    Returning to the embodiment of FIG. 9, once proper placement of the optical prosthesis has been confirmed, the incision (or incisions) used for implantation may be closed (step  945 ). The process may then be repeated in the other eye, if necessary, either in the present procedure or at a future time when the functioning of the first implanted optical prosthesis is confirmed. A separate second procedure may, of course, present the opportunity to make any necessary adjustments to the first installed device. And although repeated opening of each implant-containing eye is not presently considered desirable, it may be necessary to perform the procedure again to install a different optical arrangement if further degradation of the macular area occurs.  
         [0060]    The invention having now been fully described, it should be understood that the invention may be embodied in other specific forms or variations without departing from its spirit or essential characteristics. Accordingly, the embodiments described above are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.