corneal implants

Abstract

A precursor (100) of a corneal implant (1) including a structure (2), the structure (2) including an outer ring (10), an inner ring (11), and a connecting structure (20) pre-positioned to connect the outer ring (10) and the inner ring (11), wherein the outer ring (10), the inner ring (11), and the connecting structure (20) are located in one and the same plane, and the outer ring (10) and the inner ring (11) are located a first distance apart. The connecting structure is designed to undergo deformation to obtain a predetermined dome-shaped shape of the structure (2), wherein the outer ring (10) is located in the first plane, and the inner ring (11) is located in a second plane different from and parallel to the first plane, a second distance apart from the outer ring (10), the second distance being greater than the first distance. The connecting structure (20) includes at least one connecting element (23) for connecting the outer ring to the inner ring, the connecting element (23) extending along a profile (22) that deviates from a connecting path of a minimum length equal to the first distance, thereby having a length that exceeds the first distance so as to cover the second distance between the outer ring and the inner ring in the dome-shaped configuration of the structure.

Description

[Technical Field]

[0001] The present disclosure relates to corneal implants designed to correct irregularities in the curvature of a subject's cornea. [Background technology]

[0002] Corneal implants are implantable devices designed to impart a substantially regular curvature to the cornea, thus restoring an optimal optical state designed to reduce or eliminate optical aberrations that may impair, for example, visual acuity or contrast sensitivity.

[0003] Known and used treatments for corneal aberrations induced by corneal curvature irregularities may include, for example, (i) the use of contact lenses, (ii) the use of intracorneal ring segments (ICRS), i.e., circular ring segments made of polymeric materials with variable diameters and thicknesses, (iii) excimer laser ablation treatment, and (iv) treatment by incisional refractive surgery techniques. However, such techniques may present several drawbacks, for example, related to the development of infection and / or hypersensitivity in cases of advanced keratoconus when contact lenses are used; ICRS may have limited ability to impart a regular curvature to the cornea; ablation treatments may result in only superficial remodeling of the cornea; and incisional refractive surgery may pose a high risk of inducing secondary corneal ectasia.

[0004] Since the 1980s, different types of corneal implants have been developed to correct the curvature of the cornea, which overcome the disadvantages of known techniques. Corneal implants that can impart a predetermined curvature to the cornea and thus treat pathological deformations are described, for example, in document EP 3 801 386 A1. Summary of the Invention

[0005] Improved and effective corneal implant solutions that allow for more satisfactory treatment of corneal curvature irregularities are currently of interest.

[0006] According to the invention, the above object is achieved thanks to the solutions specified in the appended claims, which form an integral part of this disclosure.

[0007] One embodiment of the present disclosure relates to corneal implants, precursors to corneal implants, and implants resulting therefrom after transformation of the precursors.

[0008] A corneal implant configured to correct curvature irregularities in a subject's cornea has a dome-shaped structure designed to impart a predetermined curvature to a portion of the cornea that comes into contact with the implant, the structure including: an outer ring having a central axis, the outer ring located in a first plane; an inner ring disposed about the central axis and located in a second plane offset relative to the first plane along the central axis; and a connecting structure pre-positioned to connect the outer ring and the inner ring, the connecting structure including at least one connecting element extending along a path connecting the outer ring to the inner ring, the connecting element having a profile including at least one curved section in a projection plane parallel to the first plane or the second plane.

[0009] Further embodiments of the present disclosure include a corneal implant precursor, comprising a structure, the structure comprising: an outer circumferential ring; an inner circumferential ring; and a pre-positioned connecting structure for connecting the outer circumferential ring and the inner circumferential ring, wherein the outer circumferential ring, the inner circumferential ring, and the connecting structure are located on one and the same plane, wherein the outer circumferential ring and the inner circumferential ring are located a first distance apart, and the connecting structure is designed to undergo deformation to obtain a predetermined dome-shaped configuration of the structure, wherein the outer circumferential ring is located on a first plane and the inner circumferential ring is located a first distance apart. the inner ring is located in a second plane different from and parallel to the first plane and spaced a second distance from the outer ring, the second distance being greater than the first distance, and the connecting structure includes at least one connecting element for connecting the outer ring to the inner ring, extending along a profile that deviates from a connecting path of a minimum length equal to the first distance, whereby the at least one connecting element has a length that exceeds the first distance and at least covers the second distance between the outer ring and the inner ring in the predetermined dome-shaped configuration of the structure.

[0010] Further embodiments relate to corneal implants configured to correct irregularities in corneal curvature obtained from a precursor through a process of forming a structure. In particular, the implant may be obtained by deformation of a connecting structure, where a peripheral ring is located in a first plane and an inner ring is located in a second plane different from and parallel to the first plane, and the structure has an overall dome-like configuration. [Brief explanation of the drawings]

[0011] The invention will now be described in detail, purely by way of illustrative and non-limiting example, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a perspective view of a corneal implant positioned in contact with an eyeball, according to one embodiment forming the subject of the present disclosure; [Figure 2] 1 is a cross-sectional view through an embodiment of a corneal implant forming the subject of the present disclosure; [Figure 3]1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 4] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 5] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 6] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 7] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 8] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 9] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 10] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 11] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 12] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 13] 1 illustrates a precursor to a corneal implant according to one embodiment forming the subject of the present disclosure; [Figure 14] 1 illustrates a precursor to a corneal implant according to one embodiment of the corneal implant forming the subject of the present disclosure; and [Figure 15] 1 illustrates a precursor to a corneal implant according to one embodiment of the corneal implant forming the subject of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] The invention will now be described in detail by way of purely illustrative and non-limiting examples.

[0013] In the following description, numerous specific details are presented to provide a thorough understanding of the embodiments. The embodiments may be implemented without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of particular embodiments.

[0014] Throughout this description, a reference to "one embodiment" or "one embodiment" means that a particular detail, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, phrases such as "in a particular embodiment" or "in one embodiment" that may appear in various places in this description do not necessarily always refer to one and the same embodiment. Furthermore, particular details, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0015] The headings provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.

[0016] The corneal implant forming the subject of the present disclosure is an implant having a dome-shaped structure including an outer ring, an inner ring, and a connecting structure between the two rings. This implant is designed for the treatment of patients suffering from corneal irregularities, insofar as it is capable of imparting its own curvature to the cornea, thus correcting its pathological deformation thanks to the rigidity of its structure and the presence of one or more connecting elements between the outer and inner rings; such connecting elements have at least a curved profile in a projection plane, such as the plane in which the outer ring is located. This characteristic presents the advantage that, during the drawing operation from a two-dimensional implant configuration (hereinafter "precursor") to a three-dimensional implant configuration, the one or more connecting elements can cover an increased distance between the outer and inner rings. After their formation, such connecting elements may have a length equal to or greater than the distance between the outer and inner rings. Such connecting elements may therefore follow the shape of a mold having the desired curvature without causing undesired fracture of the implant structure.

[0017] The above-mentioned properties make it possible to achieve a series of advantages with respect to known corneal implants, such as the implant described in document EP 3 801 386 A1, which present in plan view a structure with one or more series of connecting elements between the peripheral ring and the inner ring which, in the projection plane in which the peripheral ring is located, have only a linear profile.

[0018] The implants forming the subject of the present disclosure are designed to present large areas of their surface that are substantially empty or void so as not to interfere at all, or at most only minimally, with the entry of light into the eye.

[0019] The described implant may originate from a two-dimensional precursor 100, which includes a dome-shaped structure designated by reference number 2, as illustrated, for example, in FIGS. 1 and 2, and which has been deformed, preferably formed, and more preferably thermoformed. Advantageously, the precursor may be subjected to a drawing operation using a mold formed by a die and a punch, followed by a coining operation. Accordingly, the subject matter of one or more embodiments of the present disclosure may also be a precursor in which different structural elements are located on one and the same plane, as designated, for example, in FIGS. 3 to 15. Once formed, the precursor assumes a three-dimensional dome-like configuration, as illustrated, for example, in FIG. 1 and designated by reference number 2. The dome-shaped structure 2 may have a curvature in sagittal section that results in a substantially semicircular profile, as illustrated in FIG. 2, or a semi-elliptical profile, or otherwise a predetermined profile based on the subject's needs.

[0020] Similar to the precursor 100, the structure 2 of the implant 1 includes an outer ring 10 having a central axis and located on a first surface (designated AA' in FIG. 2). The structure 2 further includes an inner ring 11 disposed about the central axis and located on a second surface offset relative to the first surface along the central axis. Preferably, the outer ring 10 and the inner ring 11 are coaxial.

[0021] The structure 2 further includes a pre-positioned connecting structure 20 for connecting the outer ring 10 and the inner ring 11. The connecting structure 20 includes at least one connecting element 23 extending along a path connecting the outer ring 10 to the inner ring.

[0022] The interconnecting structure 20 includes voids (or mesh) 24. The total area of ​​the voids 24 within the interconnecting structure 20 is comprised between 40% and 99.9% of the surface of the internal structure.

[0023] Furthermore, the contour of the void portion 24 may present only a non-linear profile that does not extend over a linear segment. The contour of the void portion 24 may have only a wavy contour.

[0024] With respect to the precursor 100, the outer ring 10, the inner ring 11, and the connecting structure 20 are located in one and the same plane. Preferably, the outer ring 10 and the inner ring 11 are coaxial. Furthermore, the outer ring 10 and the inner ring 11 are located in one and the same plane, separated by a first distance (e.g., indicated by the letter D in FIG. 3). The connecting structure 20 is deformed to obtain a predetermined dome-shaped configuration of the structure 2. When the dome-shaped configuration of the structure 2 is obtained, the outer ring 10 is located in a first plane, and the inner ring 11 is located in a second plane different from and parallel to the first plane; in particular, the outer ring 10 and the inner ring 11 are located apart by a second distance greater than the first distance. The connecting structure 20 presents the characteristic of including at least one connecting element 23 for connecting the outer ring 10 to the inner ring 11, extending along a profile 22 deviating from a connecting path of a minimum length equal to the above-mentioned first distance: in particular, the connecting element 23 has a length exceeding the first distance so as to be able to cover a second distance between the outer ring 10 and the inner ring 11 in the predetermined dome-shaped configuration of the structure 2 without breaking or undergoing any uncontrollable deformation.

[0025] In other words, one or more connecting elements 23 of the implant 1 may have a length greater than the minimum distance between the outer ring 10 and the inner ring 11 (which may be understood as the length of a straight section connecting the two rings and corresponding to the shortest path between them) when the rings are positioned in the same plane (the two-dimensional configuration of the implant or the implant precursor). In particular, as shown in the figure, the connecting structure 23 includes one or more connecting elements 23 having a profile 22 including at least one curved section, preferably a serpentine section or a sickle-shaped section. For example, the distance (first distance) between the outer ring 10 and the inner ring 11 positioned in the same plane (referred to as the first distance in this disclosure) may be between 0.01 mm and 10 mm, e.g., 2.50 mm. The connecting elements 23 that deviate from the minimum length connecting path may have a length between 0.02 mm and 20 mm, e.g., 2.60 mm.

[0026] After the deformation induced by forming, the one or more connecting elements 23 can extend to cover an increased distance between the outer and inner rings without suffering from breakage or uncontrollable deformation, preferably if the connecting element or elements 23 have a profile with at least one curved section. For example, as shown in Figure 1, the one or more connecting elements 23 of the dome-shaped connecting structure 20, even after forming, have a profile 22 with at least one curved section, preferably a serpentine or sickle-shaped section.

[0027] In one or more embodiments, the connecting structure 20 of the precursor 100 , like the resulting implant 1 , may include multiple connecting elements 23 or alternatively a single connecting element 23 .

[0028] In the case of multiple connecting elements 23, they may have an irregular or otherwise uniform distribution within connecting structure 20. Connecting elements 23 may be located close to each other in one region (e.g., corresponding to a region of the cornea where keratoconus is located) and may be located more sparsely in another region (e.g., corresponding to a region of the cornea where keratoconus is absent).

[0029] In both cases, one or more connecting elements 23 may include a first end 31 connected to the outer ring 10 and a second end 32 connected to the inner ring 11. Each of the multiple connecting elements 23 or a single connecting element 23 extends along a path connecting the outer ring 10 to the inner ring 11 and has a profile that includes at least one curved section.

[0030] In one or more embodiments, multiple connecting elements 23 may have profiles that define one or more corresponding cavities oriented in the same rotational direction relative to the central axis. Examples of such embodiments are illustrated, for example, in Figures 1, 3-7, and 10-13.

[0031] When the connecting structure 20 has multiple connecting elements 23, they may have different profiles. The profiles may be sinusoidal 30 (FIGS. 1, 3, 10, 11), arched 40 (FIGS. 5-7, 13), omega-shaped 50 (FIGS. 4, 12), ring-shaped 60 (FIG. 8), or may otherwise present a combination of the above shapes.

[0032] For example, in the case of a sinusoidal profile as illustrated for the implant of FIG. 1 or the precursor 100 of FIG. 3, it may include circumferentially projecting maxima 40 and minima 42 on opposite sides of a zero point 44 .

[0033] An example of a structure 20 including at least one linking element 23 having an omega-shaped profile is shown in Figure 4. Figures 5 through 7 illustrate precursors to a corneal implant 1 in which the linking elements 23 have an arcuate profile. In particular, Figure 5 illustrates a structure 2 including seven linking elements 23 with arcuate profiles. In this example, the linking elements 23 are distributed in an asymmetric and irregular manner within the linking structure 20. Figures 6 and 7 illustrate precursors having different numbers of linking elements 23, each defining a semicircular arc. This semicircular arc may have a diameter greater than the diameter of the inner circumferential ring 11.

[0034] In one or more embodiments, the first end 31 and second end 32 of the first connecting element 23 having an arched profile may be adjacent to the respective first end 31 and respective second end 32 of the second arched connecting element 23 to form an inner ring 60 included in the connecting structure 20 between the outer ring 10 and the inner ring 11. The precursor 100, as well as the resulting implant, may include at least two pairs of elements 23 having arched profiles facing each other to form at least two inner rings 60 (FIG. 8).

[0035] 9 illustrates a precursor 100 in which the connecting structure 20 includes a single connecting element 23 having a first end 31 connected to the outer ring 10 and a second end 32 connected to the inner ring 11. In this embodiment, the connecting element 23 extends along a path connecting the outer ring to the inner ring. Preferably, the connecting element 23 follows a helical path 70.

[0036] To provide greater structural stability to the implant, the precursor 100, as well as the resulting implant, may include at least one bridge structure 26 in the connecting structure 20. The structure 26 connects adjacent elements of multiple connecting elements 23 (as illustrated in FIGS. 10-13) or otherwise connects at least two distinct points of a single connecting element 23 (as illustrated in FIGS. 14 and 15). The bridge structure 26 can provide structural stability to the implant. The bridge structure 26 may have a curved profile.

[0037] 10, a first end 27 of one bridge structure 26 is connected at a maximum or minimum point of a connecting element 23 having a sinusoidal profile, and a second end 28 of the bridge structure 26 is connected at a zero point of at least one connecting element 23 having a circumferentially continuous sinusoidal profile. Alternatively, as shown in FIG. 11, a first end 27 of the bridge structure 26 can be connected at a maximum point 40 or minimum point 42 of a connecting element 23 having a sinusoidal profile, and a second end 28 of the bridge structure 26 can be connected at a maximum point 40 or minimum point 42, respectively, of a connecting element 23 having a circumferentially continuous sinusoidal profile.

[0038] FIG. 11 illustrates an example in which a bridge structure 26 connects omega-shaped connecting elements 23 .

[0039] The bridge structures 26 may be arranged according to an annular arrangement to form at least one ring 12 intermediate and coaxial with the outer ring 10 and the inner ring 11, as shown for example in Figures 11 and 12. In Figure 13, the bridge structures 26 connect two consecutive arch-shaped connecting elements 23 and have a curved profile. Figures 14 and 15 illustrate two examples in which the bridge structures 26 are distributed between the turns of a connecting element 23 with a helical profile.

[0040] In one or more embodiments, at least one of the areas between the outer ring 10 and the inner ring 11 of the implant 1 and / or precursor 100 may have a weakened point 52 (preferably a notch), which includes opposing slits inside the connecting structure 20, as seen, for example, in Figures 4 and 12.

[0041] As described, when the connecting elements 23 of the precursor 100 are located in one and the same plane, they extend along a profile 22 that deviates from the minimum length of the connecting path between the outer and inner rings. The property of the connecting elements 23 having an excess length that allows them to cover at least the distance between the outer and inner rings 10, 11 presents an advantage during deformation, once a dome-shaped deformation of the structure is obtained. To facilitate this property, the connecting elements may have a profile with at least one curved section. In particular, even after deformation, one or more connecting elements 23 have a curved profile, rather than a straight profile, in a plan view in the projection plane where the outer ring is located.

[0042] The above characteristics offer the advantage that during the drawing operation from the two-dimensional configuration of the precursor to the three-dimensional configuration of the implant, the connecting elements 23 can cover an increasing distance between the outer and inner rings; these elements 23 can therefore take the shape of the mold with the desired curvature. This allows the structure 20 to expand and assume the appropriate curvature; the desired curvature may form an ellipsoid, the semi-axes of which may have a size comprised between 7 mm and 11 mm, for example.

[0043] It has been found that known precursors to corneal implants that include straight connecting elements do not promote sufficient stretching upon formation and are therefore less suitable for the purpose, In particular, the formation of such connecting elements can result in single or multiple breakages, as well as abnormal, undesirable, and uncontrollable deformation of the connecting elements themselves and, in certain cases, of the outer and / or inner circumferential rings.

[0044] The presence of weakened points, e.g., notches, at the level of the outer and / or inner ring also contributes to facilitating accurate forming (or thermoforming) and drawing during the manufacturing process of the implant. These weakened points may also contribute to preventing single and / or multiple fractures of the one or more connecting elements themselves, or else of the three-dimensional configuration of the precursor after (thermo)forming, or else of abnormal, undesired and uncontrollable deformation of the inner or outer ring. Furthermore, these weakened points may also contribute to preventing single and / or multiple fractures of the inner and / or outer ring or other connecting structures.

[0045] The implant forming the subject of the present disclosure may also be fabricated, for example, by three-dimensional (3D) printing. Regardless of the process used for its fabrication, the applicants note that an implant equipped with a connecting structure 20, such as one that reproduces the profile of FIGS. 3 to 15 in a projection plane parallel to the plane of the two rings, offers advantages in terms of effective correction of irregularities in the curvature of the subject's cornea, since it has a curvature that accurately follows that of a healthy human cornea. The presence of connecting elements 23 with a curved profile enhances the implant's effectiveness in achieving a predetermined corneal curvature. The absence of linear profiles within (and between) the connecting elements defines a connecting structure 20 that is free of sharp corners between the various elements. This characteristic contributes to counteracting the development of fibrosis due to non-rounded corners (especially near the implant's right-angled corners when the implant is implanted and during implantation into the subject's cornea).

[0046] In the following description of the implants, Figures 3 to 15 are in this case understood as representing the projection of the implant in question in a projection plane parallel to the first or second plane, for example the plane in which the peripheral ring is located.

[0047] The corneal implant 1 has a dome-shaped structure 2 designed to impart a predetermined curvature to the portion of the cornea that comes into contact with the implant. The structure 2 includes: an outer ring 10 having a central axis, the outer ring 10 being located on a first surface; an inner ring 11 disposed around the central axis in a second surface offset relative to the first surface along the central axis; and a connecting structure 20 pre-positioned to connect the outer ring 10 and the inner ring 11. The connecting structure 20 includes at least one connecting element 23 extending along a path connecting the outer ring 10 to the inner ring 11, the connecting element 23 having a profile 22 including at least one curved section, preferably a serpentine or sickle-shaped section, in a projection plane parallel to the first or second surface.

[0048] The interconnecting structure includes voids (or mesh) 24. The total area of ​​voids 24 within the interconnecting structure 20 is comprised between 40% and 99.9% of the surface of the internal structure.

[0049] Furthermore, the contour of the void portion 24 may have only a non-linear profile that does not extend over a linear segment. The contour of the void portion 24 may have only a wavy contour.

[0050] In one or more embodiments, the connecting structure 20 may include multiple connecting elements 23 or alternatively a single connecting element 23 .

[0051] In the case of multiple connecting elements 23, they may have an irregular or otherwise uniform distribution within connecting structure 20. Connecting elements 23 may be located close to each other in one area (e.g., corresponding to an area of ​​the cornea where keratoconus is located or where correction is required) and may be more sparse in another area (e.g., corresponding to an area of ​​the cornea where keratoconus is not located or where correction is not required).

[0052] In either case, one or more connecting elements 23 may include a first end 31 connected to the outer ring 10 and a second end 32 connected to the inner ring 11. Each of the multiple connecting elements 23 or a single connecting element 23 extends along a path connecting the outer ring to the inner ring and has a profile that includes at least one curved section.

[0053] In one or more embodiments, multiple connecting elements 23 may have profiles that define one or more corresponding cavities oriented in the same rotational direction relative to the central axis. Examples of such embodiments are illustrated, for example, in Figures 1, 3-7, and 10-13.

[0054] When the connecting structure 20 has multiple connecting elements 23, they may have different profiles. The profile may be serpentine, e.g., sinusoidal 30 (FIGS. 1, 3, 10 and 11), or else sickle-shaped, e.g., arch-shaped 40 (FIGS. 5-7 and 13), omega-shaped 50 (FIGS. 4 and 12), or ring-shaped 60 (FIG. 8), or else may present a combination of the above profiles.

[0055] For example, in the case of the sinusoidal profile illustrated for the implant of FIG. 1, it may include local maxima 40 and minima 42 that project circumferentially on opposite sides from a zero point 44 .

[0056] An example of a structure 20 including at least one linking element 23 having an omega-shaped profile is shown in Figure 4. Figures 5 to 7 illustrate linking elements 23 having an arched profile. In particular, Figure 5 illustrates a structure 20 including seven linking elements 23 having arched profiles. In this example, the linking elements 23 are distributed in an asymmetric and irregular manner within the linking structure 20. Figures 6 and 7 illustrate different numbers of linking elements 23 defining semicircular arcs. Such semicircular arcs may have a diameter greater than the diameter of the inner circumferential ring 11.

[0057] In one or more embodiments, the first end 31 and second end 32 of the first connecting element 23 having an arched profile may be adjacent to the respective first end 31 and respective second end 32 of the second arched connecting element 23 to form an inner ring 60 included in the connecting structure 20 between the outer circumferential ring 10 and the inner circumferential ring 11. The implant may include at least two pairs of elements 23 having arched profiles facing each other to form at least two inner rings 60 (FIG. 8).

[0058] 9 includes a single connecting element 23 having a first end 31 connected to the outer ring 10 and a second end 32 connected to the inner ring 11. In this embodiment, the connecting element 23 extends along a path connecting the outer ring to the inner ring. Preferably, the connecting element 23 follows a helical path 70.

[0059] To provide greater structural stability to the implant, the latter may include at least one bridge structure 26 in the connecting structure 20. This structure 26 connects adjacent elements of the plurality of connecting elements 23, or otherwise connects at least two different, distinct points of a single connecting element 23. The bridge structure 26 has two ends 27, 28 connected to adjacent elements of the plurality of connecting elements 23, or otherwise connected to at least two different, distinct points of a single connecting element 23. The bridge structure may provide structural stability to the implant 1. These bridge structures 26 may have a curved profile.

[0060] For example, referring to Figure 10, a first end 27 of one bridge structure 26 is connected at a maximum or minimum point of a linking element 23 having a sinusoidal profile, and a second end 28 of the bridge structure 26 is connected at a zero point of at least one linking element 23 having a circumferentially continuous sinusoidal profile. Alternatively, as shown in Figure 11, a first end 27 of one bridge structure 26 may be connected to a maximum point 40 or minimum point 42 of a linking element 23 having a sinusoidal profile, and a second end 28 of the bridge structure 26 is connected at a maximum point 40 or minimum point 42, respectively, of a linking element 23 having a circumferentially continuous sinusoidal profile. The network structure includes gaps formed between the bridge structures and linking elements, and these linking elements preferably have a contour without a profile with sharp corners that may cause fibrosis when the device is implanted in a cornea in vivo.

[0061] FIG. 11 illustrates an example in which a bridge structure 26 connects omega-shaped connecting elements 23 .

[0062] The bridge structures 26 may be arranged according to an annular configuration to form at least one ring 12 intermediate between and coaxial with the outer ring 10 and the inner ring 11, for example as shown in Figures 11 and 12.

[0063] In FIG. 13, a bridge structure 26 connects two consecutive arch-shaped linking elements 23 and has a curved profile.

[0064] 14 and 15 illustrate two examples in which bridge structures 26 are distributed between the turns of a connecting element 23 with a helical profile.

[0065] In one or more embodiments, at least one of the areas between the outer ring 10 and the inner ring 11 of the implant may have a weakened point 52 (preferably a notch), which includes opposing slits within the connecting structure 20, as seen, for example, in Figures 4 and 12.

[0066] The precursor, like the corneal implant forming the subject of the present disclosure, may have an outer ring 10 preferably having a circular shape, the diameter of which may be comprised between 1 mm and 20 mm, preferably between 5 mm and 10 mm, and an inner ring 10 preferably having a circular shape, the diameter of which may be comprised between 0.1 mm and 10 mm, preferably between 0.5 mm and 7 mm.

[0067] The outer ring 10 and / or the inner ring 11 may have a cross-sectional dimension in the plane of the peripheral rings 10, 11, i.e. width, which is preferably in the range of 10 μm to 1000 μm, more preferably comprised between 15 μm and 250 μm.

[0068] The connecting elements 23 and bridge structures 26 preferably have a width in the range of 10 to 250 μm, more preferably greater than 30 μm and less than 150 μm.

[0069] The outer ring 10, the inner ring 11, and the connecting elements 23 and bridge structures 26 have the above cross-sectional dimensions in the direction perpendicular to the width or face of the peripheral rings 10, 11, i.e., thickness, which range from 5 μm to 250 μm, and more preferably greater than 10 μm and less than 100 μm.

[0070] If the cross section of the ring and / or element is circular or elliptical, the two dimensions are substantially the same.

[0071] The voids 24 within the mesh of the connecting structure 20 are preferably 0.5 mm each. 2 and 2.5mm 2 The area is included between

[0072] The total surface of the mesh is preferably 2 mm 2 and 40mm 2 The area is included between

[0073] The total volume of the mesh is preferably 0.10 mm 3 and 0.80 mm 3 is included between.

[0074] The total weight of the mesh is preferably comprised between 0.001 g and 0.004 g.

[0075] The corneal implants forming the subject of the present disclosure present mechanical and structural properties, in particular a stiffness higher than that of the corneal tissue, that allow them to impart their own curvature to the cornea, and these structural properties of the implant, after its surgical implantation beneath the corneal stromal thickness or corneal epithelium, allow the restoration of optimal optical conditions by providing a regularly shaped cornea with deformations that would otherwise produce optical aberrations that impair, for example, visual acuity or contrast sensitivity.

[0076] In one or more embodiments, the precursor and / or implant may be made of a material selected from the following: metals and corresponding alloys, such as grade 1 or grade 2 titanium, nickel, cobalt, chromium, tantalum, gold, silver, iron and their alloys (steel, Nitinol, Ti6Al4V, AISI301®, etc.); carbon and its compounds, preferably inorganic compounds; polymers; ceramic materials; combinations thereof; superelastic materials, preferably cobalt chromium alloys (Phynox); and nickel- and cobalt-free stainless steel (Bascroy).

[0077] The stiffness of the human cornea evaluated through measurement of Young's modulus is found to be in the range of 0.01 to 50 MPa, preferably 0.1 to 30 MPa.

[0078] Generally, the stiffness of the corneal implants forming the subject of the present disclosure is preferably greater than 1 MPa, more preferably greater than 30 MPa, and even more preferably comprised in the range of 50 MPa to 300 GPa.

[0079] On the other hand, as a result of its rigidity, the device allows a reduction of optical aberrations generated by both the anterior and posterior corneal surfaces when the implant is inserted into the corneal stroma ("anterior" and "posterior" are to be understood with respect to the position where the corneal implant is inserted into the cornea), a correction that cannot be achieved by ablation with an excimer or femtosecond laser, or with ring-shaped corneal implants such as ICRS, or again with implants made of non-rigid materials such as textiles, or otherwise with connecting elements or bridge structures that do not confer structural properties to the implant. If the implant is located under the corneal epithelium, the latter will regenerate by repopulating, incorporating the implant and taking its shape, smoothing and flattening any possible irregularities induced in the corneal tissue by the presence or geometry of the mesh, and filling any voids present in the mesh.

[0080] Furthermore, after surgical treatment, which may involve corneal incisions, the corneal tissue has lower structural strength compared to pre-cut corneal tissue, and therefore is better able to adapt to the new geometry imparted by the corneal implant, resulting in quantitatively superior optical results. In other words, the cornea with the corneal implant inserted has a structural rigidity suitable for adequately maintaining the optical correction imparted by the corneal implant over time.

[0081] On the other hand, given the rigidity of the corneal implants described herein, the implants are able to retain their dome-shaped configuration even after stress is applied during implantation (e.g., due to the surgeon handling the implant) or during everyday use (e.g., due to the patient rubbing their eye).

[0082] The device is indicated in all pathological conditions that may result in irregularities in the corneal curvature that produce optical aberrations that cannot be corrected with glasses or contact lenses, for example, or in subjects who cannot tolerate contact lenses, preferably provided that the stroma has sufficient transparency.

[0083] Additionally, the devices forming the subject of the present disclosure may be implanted to change the corneal curvature in healthy subjects to correct refractive error.

[0084] The main categories of patients for which the device is intended include subjects with non-inflammatory corneal ectasia (e.g., keratoconus and pellucid marginal degeneration or otherwise ectasia after corneal refractive surgery procedures) and subjects who have undergone deep anterior penetrating or lamellar keratoplasty and present with irregular or significant astigmatism.

[0085] The use of the corneal implant, which forms the subject of the present disclosure, also makes it possible to achieve the following advantages: Thanks to the mechanical rigidity of the network structure, the corneal implant allows modeling of the cornea by obtaining and imposing a predefined curvature, in contrast to what occurs with the use of ICRS and without tissue ablation, as occurs in the case of ablation treatments with excimer or femtosecond lasers, where the final shape of the cornea is not precisely predictable and the treatment is irreversible. On the other hand, thanks to the large area of ​​the voids 24 of the network structure's mesh compared to the total area of ​​the network structure itself, the corneal implant, which forms the subject of the present disclosure, i) does not interfere (or at most only interferes to a generally negligible extent) with the passage of oxygen and other molecules through the anterior and posterior corneal tissue to the implant, and ii) produces negligible diffractive phenomena and a reduction of the incident light of 5 to 10%, compared to the advantages achieved by the implant 1 in terms of the reduction of low-order aberrations (astigmatism) and high-order aberrations (such as coma and trefoil aberrations). Due to the location of the corneal implant near the nodal point of the eye, the implant itself is virtually imperceptible by the patient.

[0086] The corneal implants forming the subject of the present disclosure can preferably be implanted within the corneal stroma or fixed to the anterior surface of the corneal stroma beneath the corneal epithelium, while the implants can be easily implanted and removed with no or minimal damage to the corneal tissue, significantly reducing post-operative pain and speeding up visual recovery, thus improving the patient's quality of life.

[0087] The implants forming the subject of the present disclosure present clear advantages in terms of effective correction of irregularities in the curvature of the target cornea, insofar as they have a curvature that accurately follows the curvature of a healthy human cornea, and do not, for example, undergo during the fabrication process of the formation: i) single and / or multiple breaks of the connecting elements, and / or the inner and / or outer rings; ii) abnormal deformations; and iii) undesirable and uncontrollable deformations of the three-dimensional configuration.

[0088] The dimensions of the corneal implant 1, understood as the diameter of the peripheral ring 10, the diameter of the inner peripheral ring 11, the radius of curvature of the dome-shaped structure 2, and the thickness of the peripheral rings 10, 11 and / or elements 23 and 26, are selected to suit the patient's specific needs and corneal morphology.

[0089] Corneal implant transplantation The implants forming the subject of the present disclosure can be implanted in the patient's cornea by means of a conservative additive refractive type surgical operation that does not envisage the removal of corneal tissue.

[0090] The device may preferably be implanted into the corneal stroma, but may also be fixed to the anterior surface of the corneal stroma, beneath the corneal epithelium, or beneath Bowman's membrane.

[0091] In the case of intrastromal implantation, a circular pocket, preferably with a diameter of 6 to 12 mm, is formed in the stroma, preferably using a femtosecond laser, at a depth quantifiable in the range of 10 to 700 μm, preferably between 70 and 400 μm, relative to the anterior corneal surface, or else a side incision with a length of 2 to 5 mm is prepared, made using a microkeratome or femtosecond laser, into which the device is folded back and then inserted. Alternatively, if the material of the implant does not allow the latter to fold back back, it is also possible to provide a flap with a diameter quantifiable in the range of 3 to 11 mm, preferably between 5 and 9 mm, and a thickness of 50 to 500 μm, preferably between 70 and 400 μm.

[0092] The free margin of the flap, or the anterior layer of the pocket, or the side incision, can be secured to the adjacent tissue with sutures or otherwise with metal clips or otherwise with fibrin glue.

[0093] Furthermore, by ablation of tissue using an excimer or femtosecond laser, it is possible to obtain a negative in the corneal stroma having a shape that exactly matches the corneal implant, into which the corneal implant itself is then inserted.

[0094] Materials that can be used to make corneal implants Corneal implants may be obtained using metals and corresponding alloys (examples may include titanium, such as grade-1 or grade-2 titanium, nickel, cobalt, chromium, tantalum, gold, silver, iron, and alloys thereof, such as steel, nitinol, Ti6Al4V, AISI301®), preferably non-magnetic metals; carbon and its compounds, preferably inorganic compounds; polymers; ceramic materials; and combinations thereof. Further materials that may be used may be chosen between superelastic materials, such as cobalt-chromium alloys (Phynox), and nickel- and cobalt-free stainless steel (Bascroy).

[0095] Corneal implant 100 may also be obtained using the above materials further mixed with other compounds, such as, for example, hydroxyapatite, polylactic acid, polycaprolactone, fibroin, chitin, cellulose, chitosan, gelatin, carboxymethylcellulose, (human or animal) collagen, hydrocolloids, hydrogels, Clavion®, silver, etc.

[0096] Additionally, the corneal implant 100 may be provided with a biocompatible and / or biodegradable outer coating or void filler, optionally containing pharmacologically active ingredients, preferably anti-inflammatory, antibacterial, and / or designed to inhibit or control peri-implant fibrotic responses, or may be provided with an otherwise active outer coating or void filler capable of inducing regeneration of damaged corneal tissue, such as donor-derived somatic cells differentiated into corneal epithelial cells and corneal endothelial cells, or otherwise iPS (induced pluripotent stem) cells from a healthy donor differentiated into limbal stem cells and corneal endothelial cells using established methods.

[0097] The outer coating may be obtained using compounds and / or compositions known in the field of implantation of devices in the animal body for the release of active ingredients by the implantation device / device. Particularly preferred materials for the fabrication of biocompatible and / or biodegradable coatings for corneal implants are selected from the following: hydroxyapatite, polylactic acid, polycaprolactone, fibroin, chitin, cellulose, chitosan, gelatin, carboxymethylcellulose, (human or animal) collagen, hydrocolloids, hydrogels, Clavione®, silver, and combinations thereof.

[0098] Method for fabricating a corneal implant In the following, purely by way of non-limiting example, several methods are described for producing the corneal implant illustrated in FIG.

[0099] A) To obtain the precursor 100, a foil of commercially pure titanium (CP-Ti, ASTM B 265, grade 2, with a thickness of 0.05 mm - Lamina SpA) is used as starting material, for example, and the titanium foil is subjected to a cutting operation by laser machining.

[0100] The laser machining is performed using a StarFemto FX laser (Rofin Baasel Lasertech GmbH & Co. KG) with an ultrashort pulsed light source with the following process parameters: (Wavelength: 1030nm (Condensing optical system: F100 (Galvo scanner head: S14 (Galvo scanner head scanning speed: 200 mm / s (Field of view size: 40mm x 40mm ( Pulse duration: 250fs ( Pulse energy: 20μJ (Repetition rate: 20kHz Laser machining may also be performed using a StarFiber 180FC fiber light source (Rofin Baasel Lasertech GmbH & Co. KG). The results in terms of cutting precision are as good as the solution obtained with the StarFemto FX laser, but considering the heat input there are deformations and a lower cut wall quality than that obtained with the StarFemto FX laser fitted with an ultrashort pulsed light source.

[0101] Subsequently, a chemical treatment of electropolishing is carried out according to techniques well known in the art to clean the surface and remove unwanted contaminants therefrom.

[0102] After electropolishing, the part can undergo a passivation / anodization treatment if it is desired to introduce a color change in the part.

[0103] The anodization treatment of a single part made of titanium is obtained by the following procedure: the part is immersed for 10 seconds at room temperature in a basic aqueous solution containing 10% ammonium sulfate. The potential applied varies depending on the desired coloration, and as a non-exhaustive example, we provide the following indications regarding the potentials applied and the colors that can be obtained: -Dark brown: 12~15V; -Purple: 35~40V; -Light blue: 25~30V; -Blue: 30V; -Yellow: 40V.

[0104] The precursor is subjected to a drawing and subsequent coining operation using a mold formed by a die and a punch to impart a generally dome-shaped configuration to the interlocking structure 20. The die and punch are made of hardened material (K100).

[0105] To fabricate the corneal implant prototype, the drawing and coining steps are preferably carried out using a mechanical press with a precision laboratory mechanical toggle (Gächter, 5HKPU) with a punch accuracy of ±10 μm and a pressure value of 9 kg.

[0106] For small batch production, the drawing and coining steps are preferably carried out using a press with a motorized lowering ram (Alphamatic, Colombo) with a punch accuracy of ±10 μm and a pressure value of 9 kg.

[0107] At the end of the above steps, a subsequent final cleaning (e.g., in an ultrasonic bath) may be envisaged in order to remove any possible further residues still present on the surface of the corneal implant at the end of the manufacturing process.

[0108] The corneal implant may also be subjected to one or more mechanical, laser, chemical, or any other type of operation aimed at modifying the surface morphology of the implant itself. Some possible mechanical operations are shot peening, corundum sandblasting, and passivation (which restores maximum corrosion resistance and promotes the formation of a passive layer of oxide film).

[0109] B) If the starting material is constituted by an electrowelded mesh, this is subjected to a laser machining cutting operation in order to separate the meshwork 20 and obtain the peripheral rings 10.

[0110] Subsequently, the manufacturing method may envisage the implementation of all or only some of the steps already described above with respect to the use of a starting material in the form of a foil, such as electrolytic polishing, anodizing, drawing, and possible further treatments designed to modify the surface morphology of the implant.

[0111] C) The corneal implant may be obtained by 3D printing of the final implant or may otherwise be produced from wax, from which the implant forming the subject of the present disclosure is then obtained by lost-wax casting, in the latter case a model made from wax is used to produce the final part of the desired material, by the usual lost-wax casting techniques.

[0112] D) The corneal implant may also be made of a material such as Nitinol, whereby the forming is a thermoforming process, in which case the corneal implant may be obtained using the operating conditions for thermoforming known in the art.

[0113] Determination of Young's modulus of corneal implants To determine the Young's modulus of the device forming the subject of the present invention, various types of tests known to those skilled in the art, such as tensile tests, can be carried out: 1) on a plate-type specimen made of the same material from which the device is subsequently obtained; 2) on a single beam similar to that which constitutes the device; or else 3) on the final device.

[0114] In case 1), it is expedient to use a machine that is appropriately sized for the ultimate tensile strength of the material being tested; in this case, usable load cells may reach up to 3000 kN.

[0115] In case 2), it is advantageous to use a tensile testing machine of suitable size, preferably equipped with a load cell in the range of 10 N to 10 kN, and it is necessary to have a corrugated element representing the instrument beam of sufficient length to carry out the test, preferably greater than 20 mm.

[0116] In case 3), the same modalities as in case 1) can be used, but take into account that the load applied in the first part of the tensile test is used to flatten the dome-shaped device to make it planar, and is not intended to determine the Young's modulus. (Other possible items) (Item 1) A precursor (100) of a corneal implant (1) comprising a structure (2), said structure (2) comprising: -peripheral ring (10); - inner ring (11); and - a pre-arranged connecting structure (20) for connecting the outer ring (10) and the inner ring (11); Equipped with wherein the outer ring (10), the inner ring (11), and the connecting structure (20) are located on the same plane; Here, the outer ring (10) and the inner ring (11) are positioned a first distance apart, the connecting structure (20) is designed to undergo deformation to obtain a predetermined dome-shaped configuration of the structure (2), wherein the outer ring (10) is located in a first plane and the inner ring (11) is located in a second plane different from and parallel to the first plane, spaced apart from the outer ring (10) by a second distance greater than the first distance; wherein the connecting structure (20) comprises at least one connecting element (23) for connecting the outer ring to the inner ring, the connecting element (23) extending along a profile (22) deviating from a connecting path of a minimum length equal to the first distance, whereby the at least one connecting element (23) has a length exceeding the first distance so as to cover the second distance between the outer ring and the inner ring in the dome-shaped configuration of the structure. Precursor (100) of corneal implant (1). (Item 2) Item 2. The precursor (100) of a corneal implant (1) according to item 1, wherein the profile (22) of the connecting element (23) comprises at least one curved section. (Item 3) A precursor (100) of a corneal implant (1) according to item 1 or 2, wherein the connecting structure (20) includes a plurality of connecting elements (23), each of which has a first end (31) connected to the outer ring (10) and a second end (32) connected to the inner ring (11). (Item 4) 4. The precursor (100) of a corneal implant (1) according to item 3, wherein the profile (22) is a profile selected from a sinusoidal (30), an arched (40), an omega-shaped (50), a ring-shaped (60), or a combination thereof. (Item 5) A precursor (100) of a corneal implant (1) according to item 3 or 4, wherein the plurality of connecting elements (23) have a profile defining one or more corresponding cavities oriented in the same rotational direction relative to the central axis. (Item 6) A precursor (100) of a corneal implant (1) according to item 1 or 2, wherein the connecting structure (20) comprises a single connecting element (23) having a first end (31) connected to the outer ring (10) and a second end (32) connected to the inner ring (11). (Item 7) 7. The precursor (100) of a corneal implant (1) according to item 6, wherein the connecting element (23) unfolds according to a spiral path (70). (Item 8) A precursor (100) of a corneal implant (1) according to any one of items 1 to 7, wherein the connecting structure (20) further comprises at least one bridge structure (26) for connecting two adjacent elements of the plurality of connecting elements (23) or otherwise two different separate points of the connecting elements (23). (Item 9) A corneal implant (1) configured to correct an irregularity in the curvature of a subject's cornea, said implant (1) having a dome-shaped structure (2) designed to impart a predetermined curvature to a portion of the cornea that comes into contact with said implant, said structure (2) comprising: - a peripheral ring (10) having a central axis, said peripheral ring (10) being located on the first surface; an inner ring (11) disposed around the central axis in a second surface offset relative to the first surface along the central axis; and a connecting structure (20) arranged in advance to connect the outer ring (10) and the inner ring (11), the connecting structure (20) including at least one connecting element (23) extending along a path connecting the outer ring (10) to the inner ring (11); Including, The connecting element (23) has a profile (22) including at least one curved section in a projection plane parallel to the first surface or the second surface. Corneal implants (1). (Item 10) Item 10. The corneal implant (1) according to item 9, wherein the connecting structure (20) includes a plurality of connecting elements (23), each of which includes a first end (31) connected to the outer circumferential ring (10) and a second end (32) connected to the inner circumferential ring (11), wherein each element of the plurality of connecting elements (23) extends along a path connecting the outer circumferential ring to the inner circumferential ring and has, in a projection plane parallel to the first plane or the second plane, a profile (22) including at least one curved section. (Item 11) Item 11. The corneal implant (1) according to item 10, wherein the profile (22) of the plurality of connecting elements (23) is a profile selected from a sinusoidal (30), an arched (40), an omega-shaped (50), a ring-shaped (60), or a combination thereof. (Item 12) Item 12. The corneal implant (1) according to item 11, wherein the plurality of connecting elements (23) have a profile defining one or more corresponding cavities oriented in one and the same rotational direction relative to the central axis. (Item 13) The connecting structure (20) includes a single connecting element (23) having a first end (31) connected to the outer ring (10) and a second end (32) connected to the inner ring (11); Item 10. The corneal implant (1) according to item 9, wherein the connecting element (23) extends along a path connecting the outer ring to the inner ring and has a profile (22) in a projection plane parallel to the first surface or the second surface, the profile including at least one curved section, wherein preferably the connecting element (23) develops according to a spiral path (70). (Item 14) 14. The corneal implant (1) according to any one of items 9 to 13, wherein the connecting structure (20) further comprises at least one bridge structure (26) for connecting two adjacent elements of the plurality of connecting elements (23) or otherwise two different and separate points of the connecting elements (23). (Item 15) A corneal implant (1) configured to correct an irregularity in the curvature of a subject's cornea, the implant being obtained from a precursor according to any one of items 1 to 8 through a process for forming the structure (2), wherein the connecting structure is subjected to a deformation such that the outer circumferential ring (10) is located on a first surface, the inner circumferential ring (11) is located on a second surface different from and parallel to the first surface, and the structure (2) as a whole assumes a predetermined dome-shaped form.

Claims

1. 1. A corneal implant precursor comprising a structure, the structure comprising: - peripheral ring; - an inner ring; and - pre-arranged connecting structures for connecting the outer ring and the inner ring; Equipped with wherein the outer ring, the inner ring, and the connecting structure are located on one and the same plane; wherein the outer ring and the inner ring are positioned a first distance apart, the connecting structure is designed to undergo deformation to obtain a predetermined dome-shaped configuration of the structure, wherein the outer ring is located in a first plane and the inner ring is located in a second plane different from and parallel to the first plane and spaced apart from the outer ring by a second distance greater than the first distance; wherein the connecting structure includes at least one connecting element for connecting the outer ring to the inner ring, the connecting element extending along a profile that deviates from a connecting path of a minimum length equal to the first distance, whereby the at least one connecting element has a length that exceeds the first distance to cover the second distance between the outer ring and the inner ring in the dome-shaped configuration of the structure. Corneal implant precursor.

2. The corneal implant precursor of claim 1 , wherein the profile of the connecting element includes at least one curved section.

3. The corneal implant precursor of claim 1 , wherein the connecting structure includes a plurality of connecting elements, each having a first end connected to the outer ring and a second end connected to the inner ring.

4. The corneal implant precursor of claim 3 , wherein the profile is selected from a sinusoidal, arcuate, omega-shaped, ring-shaped, or combinations thereof.

5. The corneal implant precursor of claim 3 , wherein the plurality of connecting elements have profiles that define one or more corresponding cavities oriented in a same rotational direction relative to a central axis.

6. The corneal implant precursor of claim 1 , wherein the connecting structure includes a single connecting element having a first end connected to the outer ring and a second end connected to the inner ring.

7. The corneal implant precursor of claim 6 , wherein the connecting elements deploy according to a helical path.

8. The corneal implant precursor of claim 1 , wherein the connecting structure further includes at least one bridge structure for connecting two adjacent elements of the plurality of connecting elements or otherwise two different separate points of the connecting elements.

9. 1. A corneal implant configured to correct an irregularity in the curvature of a subject's cornea, the corneal implant having a dome-shaped structure designed to impart a predetermined curvature to a portion of the cornea that comes into contact with the corneal implant, the structure comprising: - a peripheral ring having a central axis, said peripheral ring being located on the first surface; an inner circumferential ring disposed around said central axis in a second surface offset relative to said first surface along said central axis; and a pre-arranged connecting structure for connecting the outer ring and the inner ring, the connecting structure including at least one connecting element extending along a path connecting the outer ring to the inner ring; Including, The connecting element has a profile including at least one curved section in a projection plane parallel to the first surface or the second surface. Corneal implants.

10. 10. The corneal implant of claim 9, wherein the connecting structure includes a plurality of connecting elements, each of which includes a first end connected to the outer peripheral ring and a second end connected to the inner peripheral ring, wherein each of the plurality of connecting elements extends along a path connecting the outer peripheral ring to the inner peripheral ring and has a profile in a projection plane parallel to the first surface or the second surface that includes at least one curved section.

11. 11. The corneal implant of claim 10, wherein the profile of the plurality of connecting elements is a profile selected from a sinusoidal, an arcuate, an omega-shaped, a ring-shaped, or a combination thereof.

12. The corneal implant of claim 11 , wherein the plurality of connecting elements have profiles that define one or more corresponding cavities oriented in a same rotational direction relative to the central axis.

13. the connecting structure includes a single connecting element having a first end connected to the outer ring and a second end connected to the inner ring; 10. The corneal implant of claim 9, wherein the connecting element extends along a path connecting the outer ring to the inner ring and has a profile in a projection plane parallel to the first surface or the second surface that includes at least one curved section, wherein preferably the connecting element extends according to a spiral path.

14. 14. The corneal implant of claim 9, wherein the connecting structure further comprises at least one bridge structure for connecting two adjacent ones of the plurality of connecting elements or otherwise connecting two different separate points of the connecting elements.

15. 9. A corneal implant configured to correct an irregularity in the curvature of a subject's cornea, the corneal implant being obtained from a precursor according to any one of claims 1 to 8 through a process for forming the structure, wherein the connecting structure is subjected to a deformation such that the outer circumferential ring is located in a first plane and the inner circumferential ring is located in a second plane different from and parallel to the first plane, and the structure as a whole assumes a predetermined dome-shaped configuration.

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