Patent Description:
Various disorders of the eye may result from diseased/damaged corneal tissue. The diseased/damaged corneal tissue can affect vision by scattering and/or distorting light and causing glare and/or blurred vision. In some cases, proper vision can only be restored by a corneal transplant which replaces the diseased/damaged corneal tissue with healthy tissue from an organ donor. For instance, treatment of keratoconus, a degenerative disorder that causes weakness and abnormal shaping of the cornea, may ultimately require corneal transplant surgery.

<CIT> discloses a method for producing a corneal implant, comprising: providing donor corneal tissue extracted from a donor cornea, the donor corneal tissue having an anterior surface and a posterior surface; forming an interior channel in the donor corneal tissue at a depth below the anterior surface, the channel having a channel shape.

Systems and methods of the present disclosure corneal employ corneal transplants to treat eyes with diseased/damaged corneal tissue. Corneal transplant procedures may involve suturing an implant of healthy corneal tissue to a recipient cornea. The sutures and other aspects of the transplant procedure, however, may cause unwanted deformation of the corneal implant and the recipient cornea. Such deformation may cause refractive errors. According to aspects of the present disclosure, a supporting structure may be embedded into the corneal implant to enhance the stability of the corneal implant and the recipient cornea and to reduce the likelihood of unwanted deformation when the corneal implant is sutured to the recipient cornea.

Disclosed herein (but not being part of the claimed subject matter) is a corneal implant including donor corneal tissue extracted from a donor cornea. The donor corneal tissue has an anterior surface and a posterior surface. The donor corneal tissue includes an interior channel formed at a depth below the anterior surface. The channel has a channel shape. The corneal implant includes a supporting structure formed from non-tissue material and is positioned in the channel. The supporting structure has a supporting-structure shape and provides support to resist deformation of the donor corneal tissue.

The present invention provides a method for producing a corneal implant including providing donor corneal tissue from a donor cornea. The donor corneal tissue has an anterior surface and a posterior surface. The method includes forming an interior channel in the corneal tissue at a depth below the anterior surface. The channel has a channel shape. The method includes positioning a supporting structure formed from non-tissue material in the channel of the donor corneal tissue. The supporting structure has a supporting-structure shape and provides support to resist deformation of the donor corneal tissue.

Disclosed herein (but not being part of the claimed subject matter) is a method for transplanting a corneal implant including providing a corneal implant. The corneal implant includes donor corneal tissue extracted from a donor cornea. The corneal tissue has an anterior surface and a posterior surface. The corneal tissue includes an interior channel formed in the donor corneal tissue at a depth below the anterior surface. The channel has a channel shape. The corneal implant includes a supporting structure formed from non-tissue material and positioned in the channel. The supporting structure has a supporting-structure shape and provides support to resist deformation of the donor corneal tissue. The method includes removing unwanted corneal tissue from a recipient cornea and correspondingly forming a cavity in the recipient cornea. The method includes positioning the corneal implant in the cavity. The method includes coupling, with sutures, the corneal implant to the recipient cornea.

Various disorders of the eye may result from diseased/damaged corneal tissue. The diseased/damaged corneal tissue can affect vision by scattering and/or distorting light and causing glare and/or blurred vision. In some cases, proper vision can only be restored by a corneal transplant which replaces the diseased/damaged corneal tissue with healthy tissue from an organ donor.

<FIG> illustrate perspective views of an example transplant procedure where a corneal implant <NUM> from a donor cornea is introduced into an eye <NUM>. As shown in <FIG>, the eye <NUM> includes a cornea <NUM>, which has diseased/damaged corneal tissue <NUM>. Treatment of the eye <NUM> via corneal transplant involves surgical removal of the diseased/damaged corneal tissue <NUM> from the eye <NUM> as shown in <FIG>. The removal of the diseased/damaged corneal tissue <NUM> correspondingly produces a cavity <NUM> in the cornea <NUM>. As <FIG> shows, the cavity <NUM> provides a bed in the cornea <NUM> for receiving the corneal implant <NUM>. In some cases, the cavity <NUM> may be further shaped with a cutting instrument (e.g., a laser) to accommodate the size and shape of the corneal implant <NUM>. Alternatively or additionally, the corneal implant <NUM> may be further shaped with a cutting instrument (e.g., a laser) to accommodate the size and shape of the cavity <NUM>. As shown in <FIG>, the corneal implant <NUM> is received into the cavity <NUM> and coupled to the recipient cornea <NUM> with one or more sutures <NUM>, e.g., fine nylon suture thread. Once the recipient cornea <NUM> has healed and fully accepts the corneal implant <NUM>, the sutures <NUM> can be removed.

<FIG> illustrate respective top views of example patterns 20a, b of sutures <NUM> that keep the corneal implant <NUM> in place for the transplant. Other implementations, however, are not limited to the example suture patterns 20a, b shown in <FIG>. In the example pattern 20a, a series of individual sutures <NUM> are arranged along the periphery of the corneal implant <NUM>, where each individual suture <NUM> passes through the recipient cornea <NUM> and the corneal implant <NUM> to couple the corneal implant <NUM> to the recipient cornea <NUM>. In the example pattern 20b, one or more sutures <NUM> each pass alternately through the recipient cornea <NUM> and the corneal implant <NUM> along the periphery of the corneal implant <NUM> and create a zig-zag pattern between the recipient cornea <NUM> and the corneal implant <NUM>. If plurality of sutures <NUM> is employed, the sutures <NUM> may form a plurality of overlapping zig-zag patterns.

Because the recipient cornea <NUM> and the corneal implant <NUM> are bodies of soft tissue, the forces and/or torques applied by the sutures <NUM> may deform the shapes of the corneal implant <NUM> and the recipient cornea <NUM>. In some cases, other aspects of the transplant procedure may also contribute to the deformations. Such deformations may result in aberrations or other abnormal shaping that affect vision by scattering and/or distorting light travelling through the recipient cornea <NUM>. Patients may require contact lenses or glasses after corneal transplants to correct refractive errors caused by such deformations.

To reduce or minimize unwanted deformation of a corneal implant and the recipient cornea <NUM>, a supporting structure is embedded into the corneal implant so that the corneal implant can resist the forces and/or torques applied by the sutures <NUM> and can maintain its desired shape more effectively. Although the supporting structure is embedded in the corneal implant, the supporting structure can also support the structure of the recipient cornea <NUM>. In general, the supporting structure enhances the stability of the corneal implant and the recipient cornea and reduces the likelihood of refractive errors after the corneal implant is transplanted into the recipient cornea <NUM>.

<FIG> illustrates an exploded view of an example corneal implant <NUM>. The corneal implant <NUM> includes corneal tissue <NUM> extracted from a donor cornea. The donor corneal tissue <NUM> may be sized and shaped with a cutting instrument (e.g., a laser) for transplant into a recipient cornea. The donor corneal tissue <NUM> has an anterior surface 202a and a posterior surface 202b. As shown in <FIG>, the donor corneal tissue <NUM> may have a substantially circular perimeter defined by an edge 202c extending between the anterior surface 202a and the posterior surface 202c. For instance, the substantially circular perimeter of the donor corneal tissue <NUM> may be approximately <NUM> in diameter. In other embodiments, however, the donor corneal tissue <NUM> may have a perimeter of another shape, e.g., ellipse, polygon, etc..

A narrow interior channel <NUM> (i.e., enclosed passageway) is formed in the donor corneal tissue <NUM> below the anterior surface 202a. According to one approach, a femtosecond laser can be focused at a depth below the anterior surface 202a to cut the channel <NUM> through the donor corneal tissue <NUM>. The channel <NUM>, for instance, may have a substantially annular shape, i.e., shaped as a thin ring, as shown in <FIG>. In addition, the channel <NUM> may be centered relative to the anterior surface 202a of the donor corneal tissue <NUM>.

The corneal implant <NUM> also includes a supporting structure <NUM>. The supporting structure <NUM> is formed from non-tissue material. For instance, in some embodiments, the supporting structure <NUM> may be formed from a plastic. In other embodiments, the supporting structure <NUM> may be formed from a nickel titanium alloy, also known as Nitinol. Like the channel <NUM>, the supporting structure <NUM> is substantially annular in shape, i.e., shaped as a thin ring. For instance, the supporting structure <NUM> may be approximately <NUM> in diameter. As shown in <FIG>, the supporting structure <NUM> may be defined by a narrow piece of material having two ends 206a, b, where the piece of material is curved so that the two ends 206a, b meet on a circle. As such, the annular shape of the supporting structure <NUM> has a small break between the two ends 206a, b.

<FIG> illustrates an example approach for positioning the supporting structure <NUM> into the channel <NUM>. A small incision <NUM> may be formed in the corneal tissue <NUM> to provide access to the channel <NUM> from the anterior surface 202a. The end 206a (or alternatively the end 206b) of the supporting structure <NUM> may be introduced into the small incision <NUM>, and the supporting structure <NUM> may be guided (i.e., fed) through the small incision <NUM> and into the channel <NUM>. The supporting structure <NUM> is sufficiently flexible to be manipulated in the manner shown in <FIG>.

<FIG> illustrates an assembled view of the example corneal implant <NUM>. In particular, the supporting structure <NUM> is positioned in the channel <NUM>. Formed from plastic, nickel titanium alloy, etc., the supporting structure <NUM> provides sufficient rigidity to support the donor corneal tissue <NUM> and to resist deformation of the donor corneal tissue <NUM>. In general, the supporting structure <NUM> is more rigid than the donor corneal tissue <NUM>, but provides sufficient flexibility for use in the eye <NUM>.

As described above, the channel <NUM> and the supporting structure <NUM> have corresponding annular shapes so that the supporting structure <NUM> can be positioned in the channel <NUM>. In some implementations, however, the channel <NUM> may have a smaller diameter than the supporting structure <NUM>. For instance, if the supporting structure <NUM> is <NUM> in diameter, the channel <NUM> may be slightly less than <NUM> in diameter. As such, when the supporting structure <NUM> is received by the channel <NUM>, the supporting structure <NUM> pushes against the tissue around the channel <NUM>, which may expand outwardly. Correspondingly, the donor corneal tissue <NUM> around the channel <NUM> applies an inward pressure on the supporting structure <NUM> to hold the supporting structure <NUM> more securely in the channel <NUM>.

Although the channel <NUM> and the supporting structure <NUM> shown in <FIG> may have substantially annular shapes, other implementations may employ other shapes, such as an ellipse. In addition, although the supporting structure <NUM> shown in <FIG> may be a single annular structure, the supporting structure <NUM> may be alternatively defined by a combination of a plurality of sub-structures. For instance, the supporting structure <NUM> may be defined by a combination of two half-circle structures that can be received into the channel <NUM> in a manner similar to a single annular structure. Furthermore, although <FIG> may illustrate the example corneal implant <NUM> with one supporting structure <NUM> positioned in one corresponding channel <NUM>, other embodiments may include more than one channel <NUM> receiving one or more respective supporting structures. For instance, an embodiment may include more than one channel <NUM> arranged concentrically to receive a respective annular supporting structure <NUM>. The additional supporting structures <NUM> may provide additional stability and resistance to deformation of the donor corneal tissue <NUM>.

As described above with reference to <FIG>, a corneal transplant involves removing diseased/damaged corneal tissue <NUM> from the eye <NUM> and correspondingly forming a cavity <NUM> in the eye <NUM>. Instead of the corneal implant <NUM>, however, the corneal implant <NUM> may be implanted into the eye <NUM>, where the supporting structure provides greater stability for the corneal implant <NUM> and the recipient cornea <NUM>. As shown in <FIG>, the cavity <NUM> also provides a bed for receiving the corneal implant <NUM>. In some cases, the cavity <NUM> may be further shaped with a cutting instrument (e.g., a laser) to accommodate the size and shape of the corneal implant <NUM>. Alternatively or additionally, the corneal implant <NUM> may be further shaped a cutting instrument (e.g., a laser) to accommodate the size and shape of the cavity <NUM>.

As shown further in <FIG>, the corneal implant <NUM> is positioned in the cavity <NUM> and sutured in place with one or more sutures <NUM>. When received in the cavity <NUM>, the anterior surface 202a of the donor corneal tissue <NUM> is aligned with the anterior surface 12a (outwardly facing surface) of the recipient cornea <NUM> and the posterior surface 202b of the donor corneal tissue <NUM> is aligned with the posterior portion 12b (interior portion) of the recipient cornea <NUM>.

As described above, the donor corneal tissue <NUM> and thus the corneal implant <NUM> may have a diameter of approximately <NUM> and the supporting structure <NUM> may have a diameter of approximately <NUM>. The supporting structure <NUM> may be positioned in the channel <NUM> which may be centered relative to the anterior surface 202a of the donor corneal tissue <NUM>. When received in the cavity <NUM>, the corneal implant <NUM> may be centered on the recipient cornea <NUM>, which may for instance be approximately <NUM> in diameter. Accordingly, the supporting structure <NUM> of approximately <NUM> may be centered on the recipient cornea <NUM>. In this case, the supporting structure <NUM> provides structural support and stability particularly for the central region of approximately <NUM> which is more critical for vision.

As described above, the one or more sutures <NUM> may apply forces and/or torques that can deform the shapes of the corneal implant <NUM> and the recipient cornea <NUM>. The supporting structure <NUM>, however, supports the structures of the corneal implant <NUM> and the recipient cornea <NUM> to reduce or minimize the deformation caused by such forces and/or torques. In general, the supporting structure <NUM> enhances the stability of the corneal implant <NUM> and the recipient cornea <NUM> and reduces the likelihood of refractive errors after the transplant procedure.

Once the recipient cornea <NUM> has healed and fully accepts the corneal implant <NUM>, the sutures <NUM> can be removed. In some cases, the supporting structure <NUM> may also be removed after sutures <NUM> have been removed.

In some embodiments, the supporting structure <NUM> may be translucent (e.g., a translucent plastic) so that it does not interfere with the light entering the cornea <NUM> and affect the patient's vision. In other embodiments, the supporting structure <NUM> may be opaque and light-absorbing (e.g., dark in color), so that light entering the cornea <NUM> is not reflected by the supporting structure <NUM> to create halos or other glare in the patient's vision.

In addition to supporting the shape of the donor corneal tissue <NUM> and the recipient cornea <NUM>, the supporting structure <NUM> may be configured to modify the refractive profile of the donor corneal tissue <NUM>. In other words, the donor corneal tissue <NUM> defines a refractive profile, and in response to receiving the supporting structure <NUM> into the channel <NUM>, the supporting structure <NUM> modifies the refractive profile of the donor corneal tissue <NUM> to provide a desired refractive correction for the recipient cornea <NUM>. For instance, the supporting structure <NUM> may be configured to address myopia, hyperopia, and/or astigmatism in the recipient cornea <NUM>.

Claim 1:
A method for producing a corneal implant, comprising:
providing donor corneal tissue extracted from a donor cornea, the donor corneal tissue having an anterior surface and a posterior surface;
forming an interior channel in the donor corneal tissue at a depth below the anterior surface, the channel having a channel shape; and
positioning a supporting structure formed from non-tissue material in the channel of the donor corneal tissue, the supporting structure having a supporting-structure shape and providing support to resist deformation of the donor corneal tissue.