Corneal implant

Abstract

A precursor (100) for a corneal implant (1), the precursor (100) comprising a structural body (2) comprising an outer peripheral ring (10), an inner peripheral ring (11) and a connecting structure (20) prearranged to connect the outer peripheral ring (10) and the inner peripheral ring (11), where the outer peripheral ring (10), the inner peripheral ring (11) and the connecting structure (20) lie in the same plane, and where the outer peripheral ring (10), the inner peripheral ring (11) and the connecting structure (20) lie in the same plane. The outer peripheral ring (10) and the inner peripheral ring (11) are positioned spaced apart by a first distance. The connection structure is designed to undergo deformation to obtain a predetermined dome-like configuration of the structural body (2) in which the outer peripheral ring (10) lies in a first plane and the inner peripheral ring (11) lies in a second plane different but parallel to the first plane and at a second distance from the outer peripheral ring (10), the second distance is greater than the first distance. The connection structure (20) comprises at least one connection element (23) for connecting the outer peripheral ring to the inner peripheral ring, the connection element (23) extending along a profile (22) offset from a connection path having a minimum length equal to the first distance so as to have a length exceeding the first distance, the second distance between the outer peripheral ring and the inner peripheral ring is covered in the domed configuration of the structural body.

Description

Technical Field

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

[0002] A corneal implant is an implantable device designed to impose a substantially regular curvature on the cornea in order to restore optimal optical conditions designed to reduce or eliminate optical aberrations that could compromise, for example, visual acuity or contrast sensitivity.

[0003] Known treatments for corneal aberrations caused by curvature irregularities may include, for example, i) the use of contact lenses, ii) the use of ICRs (intracorneal ring segments), which are ring segments made of polymer materials of variable diameter and thickness, iii) ablation therapy using excimer lasers, and iv) treatment using incisional refractive surgery techniques. However, these techniques may have some disadvantages, such as the development of infections when contact lenses are used and / or intolerance in cases of advanced keratoconus; ICRs may have limited ability to impose a regular curvature on the cornea; ablation therapy may only result in surface reshaping of the cornea; and incisional refractive surgery may carry a high risk of inducing secondary corneal ectasia.

[0004] Since 1980, different types of corneal implants have been developed for correcting corneal curvature that can overcome the drawbacks of the known techniques. For example, document EP 3 801 386 A1 describes a corneal implant that can impose a predetermined curvature on the cornea and thus treat pathological deformations. Summary of the Invention

[0005] Improved and effective solutions of corneal implants that would enable an even more satisfactory treatment of irregularities in the corneal curvature are currently a subject of interest.

[0006] According to the invention, the above objects are achieved thanks to the solutions outlined in the accompanying claims, which form an integral part of the present disclosure.

[0007] Embodiments of the present disclosure relate to corneal implants, precursors for corneal implants, and implants derived therefrom after deformation of the precursors.

[0008] A corneal implant configured to correct an irregularity in the curvature of a subject's cornea has a dome-shaped structural body designed to impose a predetermined curvature on a portion of the cornea to be contacted by the implant. The structural body comprises:

[0009] an outer peripheral ring having a central axis, the outer peripheral ring lying in a first plane;

[0010] an inner peripheral ring disposed about the central axis in a second plane offset relative to the first plane along the central axis; and

[0011] a connecting structure prearranged to connect the outer peripheral ring and the inner peripheral ring, the connecting structure comprising at least one connecting element extending along a path connecting the outer peripheral ring to the inner peripheral ring,

[0012] The connecting element has, in a projection plane parallel to the first plane or the second plane, a profile comprising at least one curvilinear extension.

[0013] Another embodiment of the present disclosure includes a precursor for a corneal implant, the precursor comprising a structural body comprising:

[0014] - peripheral ring;

[0015] - an inner peripheral ring; and

[0016] - a connecting structure pre-arranged to connect the outer peripheral ring and the inner peripheral ring,

[0017] wherein the outer peripheral ring, the inner peripheral ring and the connecting structure are located in the same plane, and

[0018] wherein the outer peripheral ring and the inner peripheral ring are spaced apart by a first distance,

[0019] the connecting structure being designed to undergo deformation to obtain a predetermined dome-shaped configuration of the structural body in which the outer peripheral ring is located in a first plane and the inner peripheral ring is located in a second plane different from and parallel to the first plane and at a second distance from the outer peripheral ring, the second distance being greater than the first distance,

[0020] wherein the connection structure comprises at least one connection element for connecting the outer peripheral ring to the inner peripheral ring, the at least one connection element extending along a profile deviating from a connection path having a minimum length equal to the first distance so as to have a length exceeding the first distance, so as to cover at least the second distance between the outer peripheral ring and the inner peripheral ring in the predetermined dome-shaped configuration of the structural body.

[0021] Another embodiment relates to a corneal implant configured to correct irregularities in corneal curvature derived from a precursor by a fabrication method that forms a structural body. Specifically, the implant can be obtained by deforming the connecting structure such that the outer peripheral ring lies in a first plane and the inner peripheral ring lies in a second plane that is different from and parallel to the first plane, and the structural body as a whole exhibits a dome-shaped configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will now be described in detail by way of illustrative and non-limiting examples only, with reference to the accompanying drawings, in which:

[0023] - Figure 1 is a perspective view of a corneal implant positioned in contact with an eyeball according to an embodiment forming the subject matter of the present disclosure;

[0024] - Figure 2 is a cross-sectional view of an embodiment of a corneal implant forming the subject of the present disclosure;

[0025] - Figure 3 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0026] - Figure 4 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0027] - Figure 5 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0028] - Figure 6 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0029] - Figure 7 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0030] - Figure 8 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0031] - Figure 9 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0032] - Figure 10 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0033] - Figure 11 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0034] - Figure 12 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0035] - Figure 13 illustrates a precursor of a corneal implant according to an embodiment forming the subject matter of the present disclosure;

[0036] - Figure 14 illustrates a precursor of a corneal implant according to an embodiment of a corneal implant forming the subject matter of the present disclosure; and

[0037] - Figure 15 A precursor of a corneal implant forming an embodiment of the corneal implant of the presently disclosed subject matter is illustrated. DETAILED DESCRIPTION

[0038] The present invention will now be described in detail by way of illustrative and non-limiting examples only.

[0039] In the following description, numerous specific details are presented to provide a comprehensive understanding of the various embodiments. The various embodiments can be implemented without one or more of the specific details, or with other methods, components, materials, etc. In other cases, well-known structures, materials, or operations are not shown or described in detail so as not to obscure certain aspects of the various embodiments.

[0040] Throughout this specification, references to "an embodiment" or "one embodiment" mean that a particular detail, structure, or feature described in connection with that embodiment is included in at least one embodiment. Thus, phrases such as "in one embodiment" or "in one embodiment" that may appear at various points throughout this specification do not necessarily always refer to the same embodiment. Furthermore, in one or more embodiments, the particular details, structures, or features may be combined in any suitable manner.

[0041] The headings provided herein are for convenience only and do not interpret the scope or meaning of the various embodiments.

[0042] The corneal implant forming the subject of the present disclosure is an implant having a dome-shaped structural body comprising an outer peripheral ring, an inner peripheral ring, and a connecting structure included between the two rings. The implant is designed to treat patients suffering from irregular corneal structure, in part because the implant is able to impose its own curvature on the cornea, thereby correcting pathological corneal deformations due to the rigidity of its own structure and the presence of one or more connecting elements between the outer and inner peripheral rings; such connecting elements have at least one curved profile in a projection plane, such as the plane in which the outer peripheral rings lie. This feature presents the following advantages: during the operation of stretching the implant from a two-dimensional configuration (hereinafter referred to as a "precursor") to a three-dimensional configuration of the implant, one or more connecting elements can cover the increased distance between the outer and inner peripheral rings. Such connecting elements can have a length equal to or greater than the distance between the outer and inner peripheral rings after the implant is formed. Thus, such connecting elements can follow the shape of a mold having a desired curvature without causing undesirable disruption of the implant structure.

[0043] The above features make it possible to achieve a series of advantages over known corneal implants, such as the implant described in document EP 3 801 386 A1, which provides a structural body having one or more series of connecting elements located between an outer peripheral ring and an inner peripheral ring, said connecting elements having only a straight line profile in plan view, i.e. in the projection plane in which the outer peripheral ring lies.

[0044] The implant forming the subject of the present disclosure has been designed to present a wide area of ​​its surface which is essentially free or empty so as not to interfere at all or at most only minimally with the entry of light into the eye.

[0045] The implant described comprises a dome-shaped structural body, as for example in Figure 1 and Figure 2 The implant illustrated in FIG and denoted by reference numeral 2 can originate from a two-dimensional precursor 100 that has been deformed, preferably shaped, more preferably thermoformed. Advantageously, the precursor can be subjected to a stretching operation and subsequently embossed with a die formed by a die and a punch. Thus, the subject of one or more embodiments of the present disclosure is also a precursor, for example in Figures 3 to 15 , wherein the different structural elements lie in the same plane. Once formed, the precursor has a three-dimensional dome-shaped configuration, as for example in Figure 1 2. The dome-shaped structural body 2 may have a curvature so as to produce a substantially semicircular profile in sagittal section, as shown in FIG. Figure 2 as illustrated in , or a semi-elliptical outline, or a predetermined outline based on the subject's needs.

[0046] The structural body 2 of the implant 1, like the structural body 2 of the precursor 100, comprises a central axis and a first plane ( Figure 2 The outer peripheral ring 10 is shown in FIG. 1 (denoted by AA′ in FIG. 2 ). The structural body 2 further comprises an inner peripheral ring 11 disposed about the central axis and located in a second plane offset relative to the first plane along the central axis. Preferably, the outer peripheral ring 10 and the inner peripheral ring 11 are coaxial.

[0047] The structural body 2 further comprises a connection structure 20 prearranged to connect the outer peripheral ring 10 and the inner peripheral ring 11. The connection structure 20 comprises at least one connection element 23 extending along a path connecting the outer peripheral ring 10 to the inner peripheral ring.

[0048] The connection structure 20 comprises hollow portions (or grids) 24. The total area of ​​the hollow portions 24 within the connection structure 20 is comprised between 40% and 99.9% of the surface of the internal structure.

[0049] Furthermore, the outline of the hollow portion 24 may only have a non-straight outline that does not extend on a straight section. The outline of the hollow portion 24 may only have a wavy outline.

[0050] Referring to the precursor 100, the outer peripheral ring 10, the inner peripheral ring 11 and the connecting structure 20 are located in the same plane. Preferably, the outer peripheral ring 10 and the inner peripheral ring 11 are coaxial. In addition, the outer peripheral ring 10 and the inner peripheral ring 11 are spaced apart at a first distance (e.g., Figure 3 The connecting structure 20 is designed to be positioned in the same plane, spaced apart from each other (indicated by the letter D in the figure). The connecting structure 20 will undergo deformation to obtain the predetermined dome-shaped configuration of the structural body 2. Once the dome-shaped configuration of the structural body 2 has been obtained, the outer peripheral ring 10 is located in a first plane and the inner peripheral ring 11 is located in a second plane different from and parallel to the first plane; in particular, the outer peripheral ring 10 and the inner peripheral ring 11 are positioned at a second distance apart, which is greater than the first distance. The connecting structure 20 is characterized by including at least one connecting element 23 for connecting the outer peripheral ring 10 to the inner peripheral ring 11, the connecting element 23 extending along a profile 22 that deviates from a connection path having a minimum length equal to the first distance; in particular, the connecting element 23 has a length exceeding the first distance, making it possible to cover the second distance between the outer peripheral ring 10 and the inner peripheral ring 11 in the predetermined dome-shaped configuration of the structural body 2 without undergoing failure or any uncontrolled deformation.

[0051] In other words, when the outer peripheral ring 10 and the inner peripheral ring 11 are located in the same plane (the two-dimensional configuration of the implant or the precursor of the implant), one or more connecting elements 23 of the implant 1 can have a length that is greater than the minimum distance between the outer peripheral ring 10 and the inner peripheral ring 11 (which is understood to be the length of the stretch of a straight line connecting the two rings and corresponding to the minimum path between the two rings). In particular, as illustrated in the figures, the connecting structure 23 includes one or more connecting elements 23 having a profile 22 including at least one curved stretch, preferably a serpentine or sickle-shaped stretch. By way of example, the distance (first distance) between the outer peripheral ring 10 and the inner peripheral ring 11 located in the same plane (referred to in this disclosure as the first distance) can be comprised between 0.01 mm and 10 mm, for example, 2.50 mm. The connecting element 23 that deviates from the connection path having the minimum length can have a length comprised between 0.02 mm and 20 mm, for example, 2.60 mm.

[0052] After the deformation caused by forming, the aforementioned one or more connecting elements 23 - provided that the aforementioned one or more connecting elements 23 preferably have a profile with at least one curvilinear stretch - can extend so as to cover the increased distance between the outer peripheral ring and the inner peripheral ring without experiencing failure or uncontrolled deformation phenomena. As for example in Figure 1 As illustrated in FIG, one or more connecting elements 23 of the connecting structure 20 which already has a dome-shaped configuration have a profile 22 which, even after forming, comprises at least one curvilinear stretch, preferably a meander-like stretch or a sickle-like stretch.

[0053] In one or more embodiments, the connection structure 20 of the precursor 100 , like the connection structure 20 of the implant 1 obtained from the precursor 100 , may include a plurality of connection elements 23 or a single connection element 23 .

[0054] In the case of a plurality of connection elements 23, the plurality of connection elements 23 may have an irregular distribution or a uniform distribution in the connection structure 20. The connection elements 23 may be positioned close to each other in one area (e.g., corresponding to the area of ​​the cornea where keratoconus is located) and positioned more sparsely in another area (e.g., corresponding to the area of ​​the cornea where keratoconus is not located).

[0055] In both cases, the one or more connecting elements 23 may include a first end 31 connected to the outer peripheral ring 10 and a second end 32 connected to the inner peripheral ring 11. Each connecting element of the plurality of connecting elements 23 or a single connecting element 23 extends along a path connecting the outer peripheral ring 10 to the inner peripheral ring 11 and has a profile including at least one curvilinear stretch.

[0056] In one or more embodiments, the plurality of connecting elements 23 may have a profile that defines one or more corresponding cavities oriented in the same rotational direction relative to the central axis. Figure 1 、 Figures 3 to 7 as well as Figures 10 to 13 An example of such an implementation is illustrated in .

[0057] When the connection structure 20 has a plurality of connection elements 23, the plurality of connection elements 23 may have different profiles. The profile may be a sinusoidal shape 30 ( Figure 1 、 Figure 3 、 Figure 10 、 Figure 11 ), Arch 40( Figures 5 to 7 、 Figure 13 ), Omega 50( Figure 4 、 Figure 12 ), Ring 60( Figure 8 ), or may be a combination of the foregoing shapes.

[0058] For example, in Figure 1 Implants or Figure 3In the case of the illustrated sinusoidal profile of the precursor 100 , the sinusoidal profile may include a maximum point 40 and a minimum point 42 of circumferential projection on opposite sides relative to a zero point 44 .

[0059] exist Figure 4 An example of a structural body 20 comprising at least one connecting element 23 having an omega-shaped profile is shown in FIG. Figures 5 to 7 The figure shows a precursor of a corneal implant 1, wherein the connecting element 23 has an arched profile. In particular, Figure 5 The diagram shows a structural body 2 comprising seven connecting elements 23 having an arched profile. In this example, the connecting elements 23 are distributed within the connecting structure 20 in an asymmetrical and irregular manner. Figure 6 and Figure 7 The figure shows a precursor with a different number of connecting elements 23, each defining a semicircle. This semicircle may have a diameter greater than the diameter of the inner peripheral ring 11.

[0060] In one or more embodiments, the first end 31 and the second end 32 of the first connecting element 23 having an arcuate profile can be adjacent to the corresponding first end 31 and the corresponding second end 32 of the arcuate second connecting element 23 to form an inner ring 60 included in the connecting structure 20 between the outer peripheral ring 10 and the inner peripheral ring 11. The precursor 100, as well as the implant derived therefrom, can include at least two pairs of elements 23 having an arcuate profile, the at least two pairs of elements 23 facing each other to form at least two inner rings 60 ( Figure 8 ).

[0061] Figure 9 The precursor 100 is shown in which the connecting structure 20 comprises a single connecting element 23 comprising a first end 31 connected to the outer peripheral ring 10 and a second end 32 connected to the inner peripheral ring 11. In this embodiment, the connecting element 23 extends along a path connecting the outer peripheral ring to the inner peripheral ring. Preferably, the connecting element 23 is developed according to a helical path 70.

[0062] In order to give the implant greater structural stability, the precursor 100, like the implant derived therefrom, may include at least one bridging structure 26 in the connecting structure 20. The structure 26 connects adjacent elements (e.g. Figures 10 to 13 ) or at least two different and separate points of a single connecting element 23 (as shown in Figure 14 and Figure 15 ). The upper bridging structure 26 can give structural stability to the implant. The upper bridging structure 26 can have a curved profile.

[0063] Reference Figure 10In the precursor shown in FIG, a first end 27 of a bridge structure 26 is connected to the maximum point or minimum point of a connection element 23 having a sinusoidal profile, and a second end 28 of the bridge structure 26 is connected to the zero point of at least one connection element 23 having a sinusoidal profile that continues in the circumferential direction. Alternatively, as Figure 11 As illustrated in the figure, the first end 27 of the bridging structure 26 can be connected to the maximum point 40 or the minimum point 42 of the connecting element 23 having a sinusoidal profile, and the second end 28 of the bridging structure 26 is correspondingly connected to the maximum point 40 or the minimum point 42 of the connecting element 23 having a sinusoidal profile continuous in the circumferential direction.

[0064] Figure 11 An example is illustrated in which the bridging structure 26 connects the connecting elements 23 in an omega shape.

[0065] The bridge structures 26 may be arranged according to an annular arrangement to form at least one ring 12 located intermediately between and coaxial with the outer peripheral ring 10 and the inner peripheral ring 11, as for example in Figure 11 and Figure 12 As shown in the figure. Figure 13 In FIG. 2 , the bridge structure 26 connects two consecutive arched connecting elements 23 and has a curved profile. Figure 14 and Figure 15 Two examples are illustrated in which the bridging structures 26 are distributed between the turns of the connecting element 23 having a helical profile.

[0066] In one or more embodiments, at least one of the outer peripheral ring 10 and the inner peripheral ring 11 of the implant 1 and / or precursor 100 may have a weakened point 52 (preferably a notch) comprising a slit facing the interior of the connecting structure 20, for example, Figure 4 and Figure 12 Visible slits in the.

[0067] As described, the connecting elements 23 of the precursor 100 extend along a contour 22 that deviates from the connection path of minimum length between the outer and inner peripheral rings when the outer and inner peripheral rings lie in the same plane. The fact that the connecting elements 23 have excess length, allowing them to cover at least the distance between the outer and inner peripheral rings 10, 11, once the dome-shaped deformation of the structural body has been achieved, presents advantages during deformation. To facilitate this feature, the connecting elements can have a contour with at least one curved stretch. In particular, even after deformation, one or more connecting elements 23 do not have a straight contour in plan view, i.e., in the projection plane of the outer peripheral ring, but rather a curved contour.

[0068] The above features present the following advantages: during the operation of stretching from the two-dimensional configuration of the precursor to the three-dimensional configuration of the implant, the connecting elements 23 can cover the increasing distance between the outer peripheral ring and the inner peripheral ring; thus, these elements 23 can assume the shape of the mold with the desired curvature. This allows the structural body 20 to be unfolded and have the appropriate curvature; the desired curvature can form an ellipse, the semi-axis of which can have a dimension, for example, comprised between 7 mm and 11 mm.

[0069] Known precursors for corneal implants comprising rectilinear connecting elements do not facilitate sufficient elongation during shaping and therefore prove to be less suitable for this purpose. In particular, shaping of such connecting elements can lead to single or multiple failures and abnormal, undesirable and uncontrollable deformations of the connecting elements themselves and, in certain cases, single or multiple failures and abnormal, undesirable and uncontrollable deformations of the outer and / or inner peripheral rings.

[0070] In addition, the existence of for example recess at the weak point of the level of outer peripheral ring and / or inner peripheral ring helps to facilitate correct shaping (or thermoforming) and stretching during the production process of implant.These weak points can help to prevent single and / or multiple faults of one or more connecting elements themselves, or help to prevent abnormal, undesirable and uncontrollable deformation of the three-dimensional configuration of precursor after (heat) shaping or after inner ring or outer ring (heat) shaping.In addition, these weak points can help to prevent single fault and multiple faults of inner ring and / or outer ring or other connected structures.

[0071] The implant forming the subject of the present disclosure can also be produced, for example, by means of three-dimensional (3D) printing. The Applicant has noted that, whatever the process used for the production of the implant, the connecting structure 20 is provided so as to reproduce in a projection plane parallel to the plane of the two rings Figures 3 to 15 The implant with a contour presents an advantage in effectively correcting irregularities in the curvature of the cornea of ​​a subject because the implant has a curvature that accurately follows the curvature of a healthy human cornea. The presence of the connecting element 23 with a curved profile enhances the effectiveness of the implant in obtaining a predetermined curvature of the cornea. The absence of straight line profiles in (and between) the connecting elements defines a connecting structure 20 without sharp corners between the individual elements. This feature helps to combat the occurrence of fibrosis caused by non-rounded corners (particularly near the right angles of the implant once the implant has been implanted and during implantation into the cornea of ​​the subject).

[0072] In the subsequent description of the implant, Figures 3 to 15 In this case, it should be understood to mean the projection of the implant in question in a projection plane parallel to the first plane or the second plane, for example in the plane in which the outer peripheral ring lies.

[0073] The corneal implant 1 has a dome-shaped structural body 2 designed to impose a predetermined curvature on the portion of the cornea that is to come into contact with the implant. The structural body 2 comprises:

[0074] an outer peripheral ring 10 having a central axis, the outer peripheral ring 10 being located in a first plane;

[0075] an inner peripheral ring 11 arranged around the central axis in a second plane offset relative to the first plane along the central axis; and

[0076] a connecting structure 20 prearranged to connect the outer peripheral ring 10 and the inner peripheral ring 11. The connecting structure 20 comprises at least one connecting element 23 extending along a path connecting the outer peripheral ring 10 to the inner peripheral ring 11, said connecting element 23 having, in a projection plane parallel to the first plane or the second plane, a profile 22 comprising at least one curvilinear stretch, preferably a serpentine stretch or a sickle-shaped stretch.

[0077] The connection structure comprises hollow portions (or grids) 24. The total area of ​​the hollow portions 24 within the connection structure 20 is comprised between 40% and 99.9% of the surface of the internal structure.

[0078] Furthermore, the outline of the hollow portion 24 may have only a non-straight outline that does not extend on a straight section. The outline of the hollow portion 24 may have only a wavy outline.

[0079] In one or more embodiments, the connection structure 20 may include a plurality of connection elements 23 or a single connection element 23 .

[0080] In the case of multiple connection elements 23, the multiple connection elements 23 can have an irregular distribution or a uniform distribution in the connection structure 20. The connection elements 23 can be positioned close to each other in one area (e.g., corresponding to the area of ​​the cornea where keratoconus is present or correction is required) and positioned more sparsely in another area (e.g., corresponding to the area of ​​the cornea where keratoconus is not present or correction is not required).

[0081] In either case, the one or more connecting elements 23 may include a first end 31 connected to the outer peripheral ring 10 and a second end 32 connected to the inner peripheral ring 11. Each of the plurality of connecting elements 23 or a single connecting element 23 extends along a path connecting the outer peripheral ring to the inner peripheral ring and has a profile including at least one curvilinear stretch.

[0082] In one or more embodiments, the plurality of connecting elements 23 may have a profile that defines one or more corresponding cavities oriented in the same rotational direction relative to the central axis. Figure 1 、 Figures 3 to 7 as well as Figures 10 to 13 An example of such an implementation is illustrated in .

[0083] When the connection structure 20 has a plurality of connection elements 23, the plurality of connection elements 23 may have different profiles. The profile may be a serpentine, for example a sinusoidal 30 ( Figure 1 、 Figure 3 、 Figure 10 and Figure 11 ), or sickle-shaped, such as arched 40 ( Figures 5 to 7 as well as Figure 13 ), Omega 50( Figure 4 and Figure 12 ) or annular 60( Figure 8 ), or a combination of the foregoing profiles may be present.

[0084] For example, in Figure 1 In the case of the illustrated sinusoidal profile of the implant, the sinusoidal profile may include a maximum point 40 and a minimum point 42 of circumferential projection on opposite sides relative to a zero point 44.

[0085] exist Figure 4 An example of a structural body 20 comprising at least one connecting element 23 having an omega-shaped profile is shown in FIG. Figures 5 to 7 The diagram shows a connecting element 23 having an arched profile. In particular, Figure 5 The diagram shows a structural body 2 comprising seven connecting elements 23 having an arched profile. In this example, the connecting elements 23 are distributed within the connecting structure 20 in an asymmetrical and irregular manner. Figure 6 and Figure 7 Different numbers of connecting elements 23 defining a semicircle are shown. Such a semicircle may have a diameter greater than the diameter of the inner peripheral ring 11.

[0086] In one or more embodiments, the first end 31 and the second end 32 of the first connecting element 23 having an arched profile can be adjacent to the corresponding first end 31 and the corresponding second end 32 of the arched second connecting element 23 to form an inner ring 60 included in the connecting structure 20 between the outer peripheral ring 10 and the inner peripheral ring 11. The implant may include at least two pairs of elements 23 having an arched profile, the at least two pairs of elements 23 facing each other to form at least two inner rings 60 ( Figure 8 ).

[0087] Figure 9The connection structure 20 shown in FIG. 1 comprises a single connection element 23 comprising a first end 31 connected to the outer peripheral ring 10 and a second end 32 connected to the inner peripheral ring 11. In this embodiment, the connection element 23 extends along a path connecting the outer peripheral ring to the inner peripheral ring. Preferably, the connection element 23 is deployed according to a spiral path 70.

[0088] To provide greater structural stability to the implant, the implant may include at least one bridging structure 26 in the connecting structure 20. This structure 26 connects adjacent elements of the plurality of connecting elements 23 or at least two different and separate points of a single connecting element 23. The bridging structure 26 has two ends 27, 28 connected to adjacent elements of the plurality of connecting elements 23 or at least two different and separate points of a single connecting element 23. The bridging structures can provide structural stability to the implant 1. These bridging structures 26 can have a curved profile.

[0089] For example, refer to Figure 10 , a first end 27 of a bridge structure 26 is connected to the maximum point or minimum point of a connecting element 23 having a sinusoidal profile, and a second end 28 of the bridge structure 26 is connected to the zero point of at least one connecting element 23 having a sinusoidal profile that continues in the circumferential direction. Alternatively, as Figure 11 , the first end 27 of a bridge structure 26 can be connected to the maximum point 40 or the minimum point 42 of the connection element 23 having a sinusoidal profile, and the second end 28 of the bridge structure 26 is correspondingly connected to the maximum point 40 or the minimum point 42 of the connection element 23 having a sinusoidal profile that continues in the circumferential direction. The mesh structure includes a hollow portion formed between the bridge structure and the connection element, and the hollow portion preferably has an outer shape without a sharp corner that may cause fibrosis once the device is implanted in the cornea in vivo.

[0090] Figure 11 An example is illustrated in which the bridging structure 26 connects the connecting elements 23 in an omega shape.

[0091] The bridge structures 26 may be arranged according to an annular arrangement to form at least one ring 12 that is intermediate between and coaxial with the outer peripheral ring 10 and the inner peripheral ring 11, as for example in Figure 11 and Figure 12 As shown in the figure.

[0092] exist Figure 13 In FIG. 2 , the bridge structure 26 connects two consecutive arched connecting elements 23 and has a curved profile.

[0093] Figure 14 and Figure 15 Two examples are illustrated in which the bridging structures 26 are distributed between the turns of the connecting element 23 having a helical profile.

[0094] In one or more embodiments, at least one of the outer peripheral ring 10 and the inner peripheral ring 11 of the implant may have a weakened point 52 (preferably a notch) comprising a slit facing the interior of the connecting structure 20, for example, Figure 4 and Figure 12 Visible slits in the.

[0095] The precursor, like the corneal implant forming the subject of the present disclosure, may have an outer peripheral ring 10, preferably of circular shape, with a diameter comprised between 1 and 20 mm, preferably between 5 and 10 mm. The inner peripheral ring 10 may preferably have a circular shape, with a diameter comprised between 0.1 and 10 mm, preferably between 0.5 and 7 mm.

[0096] The outer peripheral ring 10 and / or the inner peripheral ring 11 may have a cross-sectional dimension, ie a width, in the plane of the peripheral rings 10 , 11 preferably in the range of 10 to 1000 μm, more preferably comprised between 15 and 250 μm.

[0097] The connecting elements 23 and the bridging structures 26 preferably have a width in the range of 10 μm to 250 μm, more preferably greater than 30 μm and less than 150 μm.

[0098] The outer peripheral ring 10, the inner peripheral ring 11 as well as the connecting elements 23 and the bridging structures 26 have a dimension of the aforementioned cross section, i.e. a thickness, in a direction perpendicular to the width or plane of the peripheral rings 10, 11 in the range of 5 to 250 μm, more preferably greater than 10 μm and less than 100 μm.

[0099] If the cross-section of the aforementioned rings and / or elements is circular or oval, the above two dimensions will be substantially the same.

[0100] The empty portions 24 within the mesh of the connecting structure 20 preferably each have a width comprised within 0.5 mm. 2 and 2.5mm 2 The area between.

[0101] The total surface of the grid preferably has a surface area comprised within 2 mm 2 With 40mm 2 The area between.

[0102] The total volume of the grid is preferably included in 0.10 mm 3 and 0.80mm 3 between.

[0103] The total weight of the grid is preferably comprised between 0.001 g and 0.004 g.

[0104] The corneal implant forming the subject of the present disclosure exhibits mechanical and structural characteristics, in particular a stiffness that is greater than that of the corneal tissue, for example to impose its own curvature on the cornea. These structural characteristics of the implant make it possible, after surgical implantation into the thickness of the corneal stroma or beneath the corneal epithelium, to restore an optimal optical situation by presenting the cornea with a regular shape even with deformations that, for example, produce optical aberrations that compromise visual acuity or contrast sensitivity.

[0105] In one or more embodiments, the precursor and / or implant can be made of a material selected from the group consisting of metals and corresponding alloys, such as grade 1 or grade 2 titanium, nickel, cobalt, chromium, tantalum, gold, silver, iron and alloys thereof, such as steel, nitinol, Ti6Al4V, AIS Carbon and its compounds, preferably inorganic substances; polymers; ceramic materials; and combinations thereof; superelastic materials, preferably cobalt-chromium alloy (Phynox); and stainless steel (Vasculoy) that does not contain nickel and cobalt.

[0106] The stiffness of the human cornea, assessed by measurement of the Young's modulus, was found to adopt values ​​ranging from 0.01 MPa to 50 MPa, preferably from 0.1 MPa to 30 MPa.

[0107] In general, the stiffness of the corneal implant forming the subject of the present disclosure is preferably greater than 1 MPa, more preferably greater than 30 MPa, even more preferably comprised within the range of 50 MPa to 300 GPa.

[0108] On the other hand, in the case of an implant inserted into the corneal stroma, the device makes it possible, by virtue of its rigidity, to reduce the optical aberrations generated both by the anterior corneal surface and by the posterior corneal surface (wherein “anterior” and “posterior” are to be understood relative to the position of insertion of the corneal implant into the cornea), corrections that cannot be achieved by ablation with the aid of an excimer laser or a femtosecond laser, or by an annular corneal implant such as an ICR, or again an implant made of a non-rigid material such as a fabric, or again made with connecting elements or bridge structures that also do not impart structural characteristics to the implant. In the case where the implant is positioned beneath the corneal epithelium, the corneal epithelium will recover and incorporate the implant by regeneration, thus assuming the shape of the cornea, smoothing and leveling any possible irregularities in the corneal tissue caused by the presence or geometry of the grid and filling the gaps present in the grid.

[0109] Furthermore, it is conceivable that after surgical treatment with corneal peeling, since the corneal tissue has a lower structural strength compared to pre-cut corneal tissue, it will better adapt to the new geometry imposed by the corneal implant and have a quantitatively superior optical result. In other words, the cornea in which the corneal implant has been inserted will have a structural rigidity suitable for adequately maintaining the optical correction imposed by the corneal implant over time.

[0110] On the other hand, given the rigidity of the corneal implant described herein, the implant is able to maintain its own dome-shaped configuration even after stress is applied during implantation (e.g., due to handling of the implant by the surgeon) or during daily use (e.g., due to the patient rubbing his / her eye).

[0111] The device indicates all pathological conditions that may lead to irregularities in the corneal curvature - preferably provided that the stroma has sufficient transparency - ie produce optical aberrations that cannot be corrected with glasses or contact lenses, or to subjects who cannot tolerate contact lenses.

[0112] Additionally, the devices forming the subject of the present disclosure may be implanted to alter the curvature of the cornea of ​​a healthy subject, thereby correcting refractive errors.

[0113] The primary categories of patients for which the device is intended include subjects affected by non-inflammatory ectasia of the cornea (such as, for example, keratoconus and pellucid marginal degeneration or ectasia following corneal refractive surgery) and subjects who have undergone deep anterior penetrating or lamellar keratoplasty and present with irregular or significant astigmatism.

[0114] Furthermore, the use of the corneal implant forming the subject of the present disclosure makes it possible to achieve the following benefits. Due to the mechanical rigidity of the lattice structure, the corneal implant makes it possible to model the cornea by imposing and obtaining a defined pre-conditioned curvature, contrary to what occurs with ICR and without the need for ablating tissue, as occurs in ablative treatments with excimer lasers or femtosecond lasers, where the final configuration of the cornea cannot be accurately predicted and the treatment is irreversible. On the other hand, due to the wide area of ​​the empty portions 24 of the mesh of the lattice structure compared to the total area of ​​the lattice structure itself, the corneal implant forming the subject of the present disclosure i) does not interfere (or at most interferes to a completely negligible extent) with the passage of oxygen and other molecules through the anterior and posterior corneal tissues to the implant, and ii) results in a reduction of the incident light by 5% to 10% and completely negligible diffraction phenomena, compared to the benefits achieved by implant 1 in terms of reducing low-order aberrations (astigmatism) and higher-order aberrations (such as coma and trefoil). Because the corneal implant is positioned near the node of the eye, the implant itself is essentially unnoticeable to the patient.

[0115] The corneal implant forming the subject of the present disclosure can preferably be implanted in the corneal stroma or fixed to the anterior surface of the corneal stroma below the corneal epithelium. On the other hand, the implant can be easily transplanted and removed without damaging the corneal tissue or with minimal damage to the corneal tissue, thereby significantly reducing pain in the postoperative period, accelerating visual recovery and thus improving the patient's quality of life.

[0116] The implant forming the subject of the present disclosure presents significant advantages in effectively correcting irregularities in the curvature of a subject's cornea, in part because the implant has a curvature that precisely follows the curvature of a healthy human cornea and, for example, does not experience during the forming production process: i) single and / or multiple breakages 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.

[0117] The dimensions of the corneal implant 1 are understood to be the diameter of the outer peripheral ring 10, the diameter of the inner peripheral ring 11, the radius of curvature of the dome-shaped structural body 2, and the thickness of the peripheral rings 10, 11 and / or the thickness of elements 23 and 26 will be selected to suit the specific needs of the patient and the morphology of the cornea.

[0118] Models of corneal implant transplantation

[0119] The implant forming the subject of the present disclosure can be transplanted into the cornea of ​​a patient by means of a conservative-addition refractive type of surgery that does not envisage reduction of corneal tissue.

[0120] The device may preferably be implanted in the corneal stroma, but may also be secured to the anterior surface of the corneal stroma beneath the corneal epithelium or Bowman's membrane.

[0121] In the case of an intrastromal implant, a circular cavity is formed in the stroma, preferably having a diameter of 6 mm to 12 mm, preferably prepared using a femtosecond laser at a depth quantifiable in the range of 10 μm to 700 μm, preferably 70 μm to 400 μm relative to the anterior corneal surface, or prepared using a microkeratome or femtosecond laser, and a side incision 2 mm to 5 mm in length is made in the stroma, into which the device is inserted once it has folded over itself. Alternatively, if the material from which the implant is made does not allow the implant to fold over itself, a flap having a quantifiable diameter in the range of 3 mm to 11 mm, preferably between 5 mm and 9 mm, and a thickness of 50 μm to 500 μm, preferably between 70 μm and 400 μm can also be provided.

[0122] The free edge of the flap or the free edge of the anterior layer of the pocket or side cut may be secured to the adjacent tissue using sutures or metal clips or fibrin glue.

[0123] Furthermore, a negative portion having a shape exactly corresponding to that of the corneal implant can be obtained in the corneal stroma by means of tissue ablation with an excimer laser or a femtosecond laser, into which the corneal implant itself will then be inserted.

[0124] Materials that can be used to produce corneal implants

[0125] Corneal implants can be obtained using the following materials: metals and corresponding alloys (by way of example, titanium such as titanium grade 1 or titanium grade 2, nickel, cobalt, chromium, tantalum, gold, silver, iron and its alloys such as steel, nitinol, Ti6Al4V, The materials include, but are not limited to, non-magnetic metals, carbon and its compounds, preferably inorganic compounds, polymers, ceramic materials, and combinations thereof. Other materials that can be used include superelastic materials such as cobalt-chromium alloys (Phynox) and stainless steel (Vasculoy) that does not contain nickel or cobalt.

[0126] Corneal implant 100 can also be obtained using the aforementioned materials further mixed with other compounds, such as hydroxyapatite, polylactic acid, polycaprolactone, fibrin, chitin, cellulose, chitosan, gelatin, carboxymethyl cellulose, (human or animal) collagen, hydrocolloid, hydrogel, silver.

[0127] In addition, the corneal implant 100 can provide a biocompatible and / or biodegradable outer coating or filler in the void, the outer coating or filler optionally including a pharmacologically active ingredient that is preferably anti-inflammatory, antibacterial and / or designed to inhibit or control the fibrotic response around the implant, or the corneal implant 100 can provide an outer coating or filler in the void that will be active and capable of inducing regeneration of damaged corneal tissue, such as somatic cells from a donor that are differentiated into corneal epithelial cells and endothelial cells, or iPS (induced pluripotent stem) cells from a healthy donor that are differentiated into corneal epithelial cells and endothelial cells using a comprehensive approach.

[0128] The outer coating can be obtained in an animal using compounds and / or compositions known in the art of implantable prostheses for releasing active ingredients through implantable devices / prostheses. Particularly preferred materials for producing biocompatible and / or biodegradable coatings for corneal implants are selected from the following materials: hydroxyapatite, polylactic acid, polycaprolactone, fibrin, chitin, cellulose, chitosan, gelatin, carboxymethylcellulose, (human or animal) collagen, hydrocolloids, hydrogels, Silver and its combinations.

[0129] Method for producing corneal implants

[0130] In the following, by way of non-limiting example only, a method for producing Figure 1 Some methods of corneal implants are shown in FIG.

[0131] A) Using, for example, a commercially pure titanium foil (CP-Ti from Lamina Co., Ltd., ASTM B265, Grade 2, thickness 0.05 mm) as a starting material, the titanium foil is subjected to a cutting operation by laser processing to obtain a precursor 100 .

[0132] Laser processing was performed using a StarFemto FX laser (Rofin Baasel Lasertech GmbH & Co. KG) with an ultrashort pulse source with the following process parameters:

[0133] - Wavelength: 1030nm

[0134] - Focusing optics: F100

[0135] -Galvanometer scanning head: S14

[0136] - Scanning speed of galvanometer scanning head: 200mm / s

[0137] - Field of view size: 40mm x 40mm

[0138] - Pulse duration: 250fs

[0139] -Pulse energy: 20μJ

[0140] -Repetition rate: 20kHz

[0141] Laser processing can also be performed using a StarFiber 180FC fiber source (Rofin Baasel Lasertech GmbH & Co. KG). The results in terms of cutting accuracy are just as good as those obtained with the StarFemto FX laser, but considering the heat input, the deformation and quality of the cut wall are worse than those obtained with the StarFemto FX laser equipped with an ultrashort pulse source.

[0142] Next, a chemical process of electropolishing is performed according to techniques well known in the art to clean the surface and remove undesirable contaminants from the surface.

[0143] After electropolishing, the piece may be subjected to a passivation / anodization treatment if it is desired to introduce a change in the color of the piece.

[0144] The anodized treatment of a single piece made of titanium is obtained according to the following procedure: the piece is immersed in an alkaline aqueous solution containing 10% ammonium sulfate for 10 seconds at room temperature. The applied potential varies depending on the desired color, and by way of non-exhaustive example, we provide the following indications of the applied potential and the colors that can be obtained:

[0145] - Dark brown: 12V to 15V;

[0146] - Purple: 35V to 40V;

[0147] -Light blue: 25V to 30V;

[0148] -Blue: 30V;

[0149] - Yellow: 40V.

[0150] In order to give the connecting structure 20 a substantially dome-shaped configuration, the precursor undergoes an operation of stretching and then embossing using a die formed by a stamping die and a punch. The stamping die and the punch are made of tempered material (K100).

[0151] For the production of prototypes of corneal implants, a mechanical press with a precision laboratory mechanical toggle (GECHTER, 5HKPU) is preferably used for the stretching and embossing process, wherein the punching accuracy is + / - 10 μm and the pressure value is 9 kg.

[0152] For small series production, it is preferred to use a press with an electrically actuated lowering slide (ALFAMATIC, COLOMBO) for the stretching and embossing process, with a punching accuracy of + / - 10 μm and a pressure value of 9 kg.

[0153] At the end of the above steps, a subsequent final cleaning (for example in an ultrasonic bath) can be envisaged to remove any possible other residues still present on the surface of the corneal implant at the end of the production process.

[0154] The corneal implant may also be subjected to one or more machining operations, laser operations, chemical operations or any other type of operation aimed at modifying the surface morphology of the implant itself. Some possible machining operations are shot blasting, corundum blasting and passivation (passivation restores the maximum corrosion resistance of the passive layer to the oxide film, thus promoting the formation of this oxide film).

[0155] B) In the case where the starting material consists of an electric welded mesh, it will be subjected to a cutting operation by laser machining in order to isolate the mesh structure 20 and obtain the peripheral ring 10 .

[0156] Next, the production method may envisage implementing all or only some of the steps previously described with reference to the use of a starting material in foil form, such as electropolishing, anodizing, stretching and possible other treatments designed to modify the surface morphology of the implant.

[0157] C) Corneal implants can also be obtained by means of 3D printing of the final implant, or made of wax and then the implant forming the subject of the present disclosure is obtained from the wax by lost wax casting. In the latter case, a model made of wax is used to produce the final part of the desired material according to the usual lost wax casting technique.

[0158] D) Corneal implants can also be made of materials such as Nitinol, whereby forming is a thermoforming process which becomes thermoforming. In the latter case, the corneal implant can be obtained using the operating conditions known in the art for thermoforming.

[0159] Determination of Young's modulus of corneal implants

[0160] In order to determine the Young's modulus of the device forming the subject of the invention, various types of tests known to those skilled in the art, such as tensile tests, can be carried out: 1) on plate-type specimens made of the same material as that of the device subsequently obtained; 2) on single beams similar to those constituting the device; or 3) on the final device.

[0161] In case 1), it is advantageous to use a machine that is appropriately dimensioned with respect to the ultimate tensile strength of the material being tested; in this case, load cells up to 3000 kN can be used.

[0162] In case 2), it is advantageous to use a suitably sized tensile testing machine equipped with a load cell preferably in the range of 10N to 10kN and necessarily with an undulating element representing the device beam and having a length sufficient for the test, preferably greater than 20mm.

[0163] In case 3), the same paradigm as in case 1) can be used, although taking into account that the load applied in the first part of the tensile test will serve to flatten the dome-shaped device so that it becomes planar and will not be indicated for determining the Young's modulus.

Claims

1. A precursor (100) for a corneal implant (1), the precursor (100) comprising a structural body (2), the structural body (2) comprising: - an outer peripheral ring (10); - an inner peripheral ring (11); as well as - a connecting structure (20) pre-arranged to connect the outer peripheral ring (10) and the inner peripheral ring (11), wherein the outer peripheral ring (10), the inner peripheral ring (11) and the connecting structure (20) are located in the same plane, and wherein the outer peripheral ring (10) and the inner peripheral ring (11) are spaced apart by a first distance, The connecting structure (20) is designed to undergo deformation to obtain a predetermined dome-shaped configuration of the structural body (2), in which the outer peripheral ring (10) is located in a first plane and the inner peripheral ring (11) is located in a second plane different from and parallel to the first plane and at a second distance from the outer peripheral ring (10), the second distance being greater than the first distance, The connection structure (20) comprises at least one connection element (23) for connecting the outer peripheral ring to the inner peripheral ring, the connection element (23) extending along a profile (22) deviating from a connection path having a minimum length equal to the first distance so as to have a length exceeding the first distance so as to cover the second distance between the outer peripheral ring and the inner peripheral ring in the dome-shaped configuration of the structural body.

2. The precursor (100) for a corneal implant (1) according to claim 1, wherein The profile (22) of the connecting element (23) comprises at least one curvilinear stretch.

3. The precursor (100) for a corneal implant (1) according to claim 1 or claim 2, wherein: The connection structure (20) includes a plurality of connection elements (23), each of the plurality of connection elements (23) including a first end (31) connected to the outer peripheral ring (10) and a second end (32) connected to the inner peripheral ring (11).

4. The precursor (100) for a corneal implant (1) according to claim 3, wherein The profile (22) is a profile selected from a sinusoidal shape (30), an arch shape (40), an omega shape (50), a ring shape (60), or a combination thereof.

5. The precursor (100) for a corneal implant (1) according to claim 3 or claim 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.

6. The precursor (100) for a corneal implant (1) according to claim 1 or claim 2, wherein: The connection structure (20) comprises a single connection element (23) comprising a first end (31) connected to the outer peripheral ring (10) and a second end (32) connected to the inner peripheral ring (11).

7. The precursor (100) for a corneal implant (1) according to claim 6, wherein: The connecting element (23) unfolds along a helical path (70).

8. Precursor (100) for a corneal implant (1) according to any one of the preceding claims, wherein The connecting structure (20) further comprises at least one bridging structure (26) for connecting two adjacent elements of the plurality of connecting elements (23) or two different and separate points of the connecting elements (23).

9. A corneal implant (1) configured to correct an irregularity in the curvature of a subject's cornea, the implant (1) having a dome-shaped structural body (2) designed to impose a predetermined curvature on a portion of the cornea to be in contact with the implant, the structural body (2) comprising: - an outer peripheral ring (10) having a central axis, said outer peripheral ring (10) being located in a first plane; - an inner peripheral ring (11) arranged around the central axis in a second plane offset relative to the first plane along the central axis; as well as a connecting structure (20) prearranged to connect the outer peripheral ring (10) and the inner peripheral ring (11), the connecting structure (20) comprising at least one connecting element (23) extending along a path connecting the outer peripheral ring (10) to the inner peripheral ring (11), The connecting element (23) has a profile (22) comprising at least one curvilinear stretch in a projection plane parallel to the first plane or the second plane.

10. The corneal implant (1) according to claim 9, wherein The connection structure (20) includes a plurality of connection elements (23), each of the plurality of connection elements (23) including a first end (31) connected to the outer peripheral ring (10) and a second end (32) connected to the inner peripheral ring (11), wherein each of the plurality of connection elements (23) extends along a path connecting the outer peripheral ring to the inner peripheral ring and has a profile (22) including at least one curved stretch portion in a projection plane parallel to the first plane or the second plane.

11. The corneal implant (1) according to claim 10, wherein The profile (22) of the plurality of connecting elements (23) is a profile selected from a sinusoidal shape (30), an arch shape (40), an omega shape (50), a ring shape (60), or a combination thereof.

12. The corneal implant (1) according to claim 11, wherein The plurality of connecting elements (23) have profiles defining one or more corresponding cavities oriented in the same rotational direction relative to the central axis.

13. The corneal implant (1) according to claim 9, wherein The connection structure (20) comprises a single connection element (23) comprising a first end (31) connected to the outer peripheral ring (10) and a second end (32) connected to the inner peripheral ring (11), The connecting element (23) extends along a path connecting the outer peripheral ring to the inner peripheral ring and has a profile (22) comprising at least one curved stretch in a projection plane parallel to the first plane or the second plane, wherein, preferably, the connecting element (23) develops along a spiral path (70).

14. Corneal implant (1) according to any one of claims 9 to 13, wherein The connecting structure (20) further comprises at least one bridging structure (26) for connecting two adjacent elements of the plurality of connecting elements (23) or two different and separate points of the connecting elements (23).

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 claims 1 to 8 by a fabrication method for forming the structural body (2), wherein: The connection structure undergoes deformation so that the outer peripheral ring (10) lies in a first plane and the inner peripheral ring (11) lies in a second plane different from and parallel to the first plane, and the structural body (2) as a whole assumes a predetermined dome-shaped configuration.

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