Eye surface reconstruction device

Abstract

Eye surface reconstruction device comprising an eye attachment with suction ring (20) characterized by at least one placement and holding means for a locally limited volume of reconstruction fluid arranged in the inner region of the suction ring (20), attachable at a predetermined location on the eye surface (25) within the suction ring (20) and further characterized by a rail element (22) rotatably mounted on two opposite sides of the suction ring (20) about the axis of rotation of the suction ring (20), a holder (23) displaceable along the rail element (22) for a tube (24), and a tube (24) arranged in the holder (23) parallel to the axis of rotation of the suction ring (20), wherein the tube (24) is made of a fluid-impermeable material and is vertically displaceable and fixable up to the plane of the suction ring (20).

Description

The invention relates to an ocular surface reconstruction device for defects of corneal tissue. If a corneal defect cannot be closed quickly and reliably, far-reaching complications, including blindness and loss of sight, can occur. Currently, corneal defects can only be closed with considerable effort, meaning they cannot be closed quickly and easily. Acute corneal defect coverage is currently achieved by suturing synthetic or organic materials. These materials are only partially accepted by the surrounding tissue, can cause inflammation and transmit infections, are unstable, and have poor optical properties. Amniotic membranes are regularly used, sutured onto or into the defect. However, their high variability and expensive preparation, the suture material, poor optical properties, and a potential risk of infection with human pathogens are disadvantages (FUCHSLUGER, T. [et al.]).New possibilities for ocular surface reconstruction: Membranes made of collagen and biocompatible elastomer nanofibers. In: Ophthalmologe, Der, Vol. 111, 2014, No. 11, pp. 1019-1026. - ISSN 1433-0423 (e); 0941-293X .). Furthermore, the implants used so far typically do not fit flush with the wound edge. This can lead to complications such as infections, poor adhesion, insufficient integrity of the ocular surface, or sensory disturbances for the patient. In addition, the material often has inadequate optical properties, which is a significant disadvantage for visual function. Moreover, the suture material used frequently causes subsequent problems such as inflammation and unwanted neovascularization or scarring, which can lead to implant rejection. There is a great need for techniques for the reconstruction of corneal defects that complement or replace suturing. In this context, the filling of defects with various hydrogels such as collagen, gelatin, alginate, chitosan, and fibrin, and various application techniques, e.g., with syringes, spatulas, brushes, or sprays, are proposed as state-of-the-art methods. US Patent 5,163,956 A describes a lenticule as being fused to the eye during its formation process through curing or final hardening. Such lenses allow for a smooth transition from the lens body to Bowman's layer, on which the lens is mounted. The lenticule, at the time its material or precursor is applied to the eye, may differ from being essentially all viscous collagen that flows and must be shaped to achieve a desired lenticule configuration, to a substantially stable preform that retains its shape. Such preformed lenticules can be created using a suitable mold and photopolymerization or other partial curing techniques to pre-cure the lenticule material to a suitable stage for application to the eye. Document US 2012 / 0071865A1 describes a procedure in which a hydrogel is applied to corneal wounds using a simple applicator (a small sponge on a handle). The viscosity and polymerization behavior of the hydrogel allow for the application of a small, non-precisely dosed volume of the hydrogel to the corneal defect being treated, resulting in wound closure within a short time without the need for any additional equipment. However, the application of this system is limited to very small and shallow corneal defects. Document US 4,983,580 A describes methods for treating corneal wounds by filling them with mortar compositions. These compositions can be applied to the wound by general injection or by applying them with shovel-like tools. This type of application does not allow for precise application and dosing of the filling material. Due to a shortage of donor material, a complete corneal transplant to cover defects is more commonly performed for larger defects. There is a lack of reconstructive tools for medium-sized defects. The present invention is based on the objective of providing an ocular surface reconstruction device for medium-sized defects of corneal tissue. This problem is solved by an ocular surface reconstruction device comprising an eyepiece with a suction ring, characterized by at least one means arranged in the inner region of the suction ring for placing and retaining a locally confined, low-viscosity fluid volume at a predetermined location on the ocular surface within the suction ring, according to the main claim. The ocular surface reconstruction device comprises an eyepiece with a suction ring, wherein the latter is designed by at least one placement and retention means arranged in the inner region of the suction ring for a locally confined volume of reconstruction fluid, attachable at a predetermined location on the ocular surface within the suction ring. In this regard, the eye surface reconstruction device comprises a rail element rotatably mounted on two opposite sides of the suction ring about the axis of rotation of the suction ring, a holder for a tube that is movable along the rail element, and a tube arranged in the holder parallel to the axis of rotation of the suction ring, wherein the tube is made of a fluid-impermeable material and is vertically displaceable and fixable up to the plane of the suction ring. In a further embodiment, the eye surface reconstruction device can be formed by a fluid-impermeable membrane fixed in the inner surface of the suction ring, wherein the membrane has a tubular inlet and a tubular outlet for fluids at a predetermined distance from each other, preferably on the diameter line of the suction ring. Furthermore, the membrane of the eye surface reconstruction device can be UV-permeable at least on a predetermined partial surface between the inlet and outlet for liquids. Furthermore, the ocular surface reconstruction device may have a funnel-shaped tube. When reconstructing corneal defects, especially medium-sized, irregularly shaped ones, low-viscosity liquid fillers are particularly advantageous because their gravity-driven flow allows for optimal filling of irregular defect volumes, ideally without air inclusions. The viscosity of such a liquid filler, like a collagen solution, is only increased after application and optimal distribution within the defect volume to such an extent that the filler is fixed and stabilized within the defect during healing. This is the case, for example, with the UV polymerization of liquid collagen solutions. Therefore, when applying and curing a low-viscosity liquid on a corneal defect, it is essential to ensure that it distributes optimally within the defect, fills it as completely as possible, and remains within the defect volume.This also means that it is necessary to prevent the material from running significantly beyond the defect edge during application; that is, it must be held in place after placement until it is stable and cured. The desired optimal filling of the defect is made possible by the at least one means, arranged inside a suction ring, for placing and holding a locally limited volume of fluid at a predetermined location on the ocular surface. This at least one means is designed as part of a mold for the fluid, so that the filling fluid can be applied locally to the defect, for example, by pouring or injecting the fluid into a mold formed by the said means and the corneal defect itself, when the said means is precisely positioned and fixed on the ocular surface around the defect by means of a suction ring.Because of the shape of the said agent, which is adapted to the defect, and because it is impermeable to liquids, the filling fluid applied to the defect by the agent remains essentially within the defect volume; the filling process is much more controllable and predictable than when using prior art methods. The inventive means for placing and holding a locally limited volume of liquid at a predetermined location on the surface of the eye can be attached to the suction ring or already be attached to the suction ring. The device according to the invention for placing and retaining a locally confined volume of fluid at a predetermined location on the ocular surface can, for example, be designed as a tube connected to the suction ring by lockable retaining elements and initially movable within the suction ring, or as a funnel. The tube wall can then be positioned around the defect edge on the ocular surface and fixed there by locking the retaining elements. In this state, the localized filling of the filling fluid into the defect is enabled. An alternative embodiment of the same invention concept is a membrane that can be attached to or is attached to the suction ring, which, in the attached state, essentially lies on the surface of the eye over the defect and has an inlet and an outlet for the filling fluid. Further advantages, features, and applications of the present invention will become apparent from the following description in conjunction with the figures. The elements shown in the figures serve for illustration purposes and are not drawn to scale. They show: Fig. 1 Principle of applying reconstruction fluids, such as collagen solutions, to corneal defects without an application device in three process steps A, B, and C; Fig. 2 Eye with funnel-shaped applicator, perspective view (not to scale); Fig. 3 Funnel-shaped applicator, cross-section, side view (not to scale); Fig. 4 Funnel-shaped applicators with different diameters, cross-section, side view (not to scale); Fig. 5 Injection-molded applicator, (A) side view and (B) top view (not to scale); Fig.6 injection molding applicators with different sizes and shapes of the UV-permeable area of ​​the membrane, top view. Figure 1A shows a schematic representation of the cornea 10 with a local defect 11, designated by the general reference numeral 10. Such local defects 11 can be filled with a reconstruction fluid 13, e.g., a collagen solution, as shown, for example, in Figures 1B and 1C. This fluid can be applied, for instance, with a syringe 14. The polymerization of certain reconstruction fluids 13, such as collagen solutions, can be achieved by UV irradiation 15. It is advantageous for this process if the local defect 11 is pretreated with riboflavin 12 and if the reconstruction fluid 13 also contains riboflavin 12. For example, a few drops of a 0.1% riboflavin solution can be applied to the corneal defect 11. The riboflavin 12 is transported to the wound edge by osmosis, thus enabling the reconstruction fluid 13 to subsequently bond with the still intact cornea 10.Before applying the reconstruction fluid 13, the remaining riboflavin solution is aspirated. The reconstruction fluid 13, e.g., a collagen solution, can be instilled into the corneal defect 11 using a syringe 14 or a pipette. Immediately afterward, the reconstruction fluid 13 can be crosslinked using UV light 15 and simultaneously bonded to the intact cornea at the defect margin. This creates a hydrogel that fills the defect 11. The healthy tissue of the cornea 10 should, if possible, not be damaged by the UV light 15. Even though the epithelial layer is still present and unaffected areas do not contain riboflavin 12, meaning they do not absorb the UV light 15 to the same extent, reducing the irradiation of the healthy tissue 10 around the defect 11 is advantageous.Finally, a coating can be applied to the filled defect 11 to enable re-epithelialization of the surface. This coating can consist of, for example, laminin, fibronectin, or denatured collagen. Furthermore, (limbal) stem cells or epithelial cells can be added to these proteins, allowing them to be transferred to the filled defect 11 without being damaged by UV irradiation 15. The freehand filling of a defect 11, as shown in Fig. 1, has the disadvantage of not allowing for a very precisely localized and accurately limited application of the filling fluid. The result of the procedure depends heavily on the skill of the person applying the fluid. The present invention makes it possible to overcome this disadvantage. In a preferred embodiment of the invention, the eye surface reconstruction device comprises a rail element 22 rotatably mounted on two opposite sides of the suction ring 20 about the axis of rotation of the suction ring 20, a holder for a tube 24 that is movable along the rail element 22, and a tube arranged in the holder parallel to the axis of rotation of the suction ring 20, wherein the tube is made of a liquid-impermeable material and is vertically displaceable and fixable up to the plane of the suction ring 20. In a preferred embodiment, the tube 24 is funnel-shaped (funnel applicator). The application of the reconstruction fluid 13, for example via a syringe 14 or a pipette, can be facilitated by a funnel-shaped tube 24 that tapers towards the plane of the suction ring 20. According to the invention, the tube 24 is made of a liquid-impermeable material such as plastic (for disposable products) or metal (autoclavable and therefore reusable). Fig. 2 illustrates an exemplary embodiment of such an ocular surface reconstruction device on an eye 25, which has an eye attachment with a suction ring 20 and a negative pressure supply 21. Suction rings for use on the eye are known from the prior art. By drawing the ocular surface 25 against the suction ring 20, the underlying ocular tissue is drawn to the device, thereby fixing the tissue to the device. This fixation of the tissue to the device allows the means for placing and retaining a locally limited volume of fluid at a predetermined location on the ocular surface 25, here a funnel 24, to be optimally positioned against the tissue. The suction of the tissue defines the distance to which the application area on the eye 25 is located.Thus, the means for placing a volume of fluid, located inside the suction ring 20, can be applied in a targeted and controlled manner to a predetermined location on the eye 25 that has a defect 11 to be reconstructed. The suction ring 20 is circular and has a vacuum supply 21 that can be connected to a suction device. A vacuum can be advantageously and simply created between the surface of the eye 25 and the plane of the suction ring 20 by applying a vacuum to the suction ring 20, thereby drawing the surface of the eye 25 against the plane of the suction ring 20. A vacuum in the suction ring 20 can be easily achieved using a rubber bulb, a syringe, a vacuum pump, etc. A rail element 22 is mounted on the suction ring 20 on two opposite sides of the suction ring 20 so as to be rotatable about the axis of rotation of the suction ring 20. The suction ring 20 has a guide rail 27 along its upper edge for positioning and rotating the rail element 22. The rail element 22 consists of two mirror-symmetrical, planar, elongated individual elements 26, which are shaped at both ends to engage in and slide on the guide rail 27. For application, the rail element 22 is mounted on the guide rail 27 above the ends of the individual elements 26 on both sides of the diameter line 54 of the suction ring 20, so that the entire rail element 22 can be rotated about the axis of rotation of the suction ring 20. A bracket 23, designed as a planar element, is attached to the rail element 22. This bracket connects and holds together the two individual elements 26 of the rail element 22. The bracket 23 is slidable along the rail element 22 between the two ends of the diameter line 54 of the suction ring 20. This can be achieved, for example, by bending the ends of the bracket 23 downwards along the sides parallel to the diameter line 54 of the suction ring 20, allowing them to snap around the outer sides of the two individual elements 26 and slide along the rail element 22. Fig. 3 shows a side view of the cross-section of the device from Fig. 2. The holder 23 has an opening in which a (funnel-shaped) tube 24 can be arranged parallel to the axis of rotation of the suction ring 20. The diameter of this opening is at most as large as the distance between the two individual elements 26 of the rail element 22, so that the funnel-shaped tube 24 can be pushed through to the plane of the suction ring, i.e., on the patient, to the ocular surface 25. The opening can, for example, be equipped with an internal thread 30. A tube 24 with a corresponding external thread can thus be screwed into the opening and moved vertically to the plane of the suction ring, i.e., to the ocular surface 25. By rotating the rail element 22 around the axis of the suction ring 20 or by sliding the holder 23 along the rail element 22, the funnel-shaped tube 24 can be positioned horizontally and precisely within the suction ring 20 in the holder 23. This horizontal movement, combined with the vertical movement of the tube 24 within the holder 23 towards the eye 25, allows the position of the tube 24 within the suction ring 20 on the eye surface 25 around the defect 11 to be filled to be precisely defined and maintained. According to the invention, tubes 24 with different diameters can be used for defects 11 of different sizes. Such tubes can be funnels 24 with different diameters, as exemplified in Fig. 4, wherein the diameter of the middle part of the funnel with the external thread matching the internal thread 30 in the holder 23 can remain the same, and only the part below the holder 23 towards the eye 25 has different diameters adapted to the size of the defect 11 to be filled. The material for defect reconstruction 13 can be applied through the tube 24, which is fixed to the surface of the eye 25, for example with a syringe 14, and precisely guided to the defect 11, thus preventing leakage beyond the defect edge. Other materials, such as protein solutions for coating a reconstruction fluid 13, can also be applied easily and precisely via the tube 24. The UV light for polymerizing reconstruction fluids 13 can also be directed through the tube 24, thus avoiding irradiation of the surrounding eye tissue. Not shown in Figures 2, 3 to 4 are means for locking the various movable retaining elements. Clamps, locking screws, or the like, as known per se, are suitable for this purpose. In an alternative embodiment of the same invention concept, the device comprises an attachable or already attached, either rigid or flexible, liquid-impermeable membrane 50 arranged in the inner surface of the suction ring 20, wherein the membrane 50 has an inlet 51 and an outlet 52 for liquids at a predetermined distance from each other, preferably on a diameter line 54 of the suction ring 20. Fig. 5 shows this further preferred embodiment of the device according to the invention (injection-molded applicator) consisting of a membrane 50 attached to the inner surface of a suction ring 20. The membrane 50 can be made of either a rigid or a flexible material. A flexible membrane 50 can be clamped in the inner surface of the suction ring 20 and cover this inner surface completely. Alternatively, a rigid membrane 50 can be formed as a flat, dome-shaped surface that is attached or can be attached to the inner surface of the suction ring 20 and also covers this inner surface completely. The invention is described below using a specific embodiment and the figures explained above: The membrane 50 has an inlet 51 and an outlet 52 for liquids, which are preferably located on a diameter line 54 of the suction ring 20. The inlet 51 and outlet 52 for liquids can be tubular and can have different distances from each other for defects 11 of different sizes, as shown in Fig. 6. The appropriate distance between the inlet 51 and outlet 52 is selected based on the diameter of the defect 11 to be reconstructed, so that the inlet 51 and outlet 52 open just inside the edge of the defect when attached to the eye 25. The membrane 50 is fixed to the ocular surface 10 over the defect 11 to be reconstructed by the vacuum applied to the suction ring 20 via the vacuum supply 21. This ensures that the membrane 50 is in contact with the ocular surface 25, at least at its edge. The reconstruction fluid 13 can then be injected into the inlet 51, for example, using a syringe 14. Reconstruction fluid 13 is injected slowly until the defect 11 is filled up to the ocular surface 25, and the reconstruction fluid 13 then exits at the outlet 52. This allows the defect 11 to be filled precisely, preventing leakage beyond the defect edge, as the reconstruction fluid 13 exiting the outlet 52 comes to rest on the upper surface of the membrane 50. In a preferred embodiment, the membrane 50 is UV-permeable to liquids at least on a predetermined partial surface 53 between the inlet 51 and the outlet 52. The shape of this partial surface 53 can preferably also be selected to match the contour of the defect 11 to be reconstructed. This allows a defect 11 filled with a hydrogel-forming reconstruction fluid 13 to be treated with UV light for polymerization without exposing the surrounding tissue to a high dose. A coating with proteins to improve the adhesion of epithelial cells can be applied via membrane 50. This membrane can be coated with a fleece made of laminin, fibronectin, denatured collagen, or similar materials and adheres to the surface of the reconstruction fluid 13 through contact with it. Membrane 50 can be made of a robust, flexible or rigid, and UV-permeable plastic, such as silicone. Its flexibility should be sufficient to allow Membrane 50 to adapt to the curvature of the cornea, which has a radius of curvature of approximately 7.8 mm. Preferably, the defect-filling materials to be applied with the device according to the invention are liquids such as emulsions, suspensions, colloids, dispersions, gels, in particular hydrogel-forming liquids, or solutions. The device according to the invention enables simple, fast, high-quality, and cost-effective reconstruction of corneal surfaces damaged by disease, injury, or surgery. Using the device, defects up to the maximum corneal diameter of approximately 12 mm and the entire stromal depth, i.e., down to Descement's membrane (500-600 µm), can be treated. Reference symbol list 10 Cornea, healthy tissue 11 Local defect, corneal defect 12 Riboflavin 13 Reconstruction fluid 14 Syringe 15 UV irradiation 20 Suction ring 21 Vacuum supply 22 Rail element 23 Holder 24 Tube, funnel-shaped tube, funnel 25 Eye, ocular surface 26 Single element 27 Guide rail 30 Internal thread 50 Membrane 51 Inlet 52 Outlet 53 Partial surface 54 Diameter line

Claims

Eye surface reconstruction device comprising an eye attachment with suction ring (20) characterized by at least one placement and retention means arranged in the interior of the suction ring (20) for a locally limited volume of reconstruction fluid, attachable at a predetermined location on the eye surface (25) within the suction ring (20) and further characterized by a rail element (22) rotatably mounted on two opposite sides of the suction ring (20) about the axis of rotation of the suction ring (20), a holder (23) displaceable along the rail element (22) for a tube (24), and a tube (24) arranged in the holder (23) parallel to the axis of rotation of the suction ring (20), wherein the tube (24) is made of a fluid-impermeable material and is vertically displaceable and fixable up to the plane of the suction ring (20). Eye surface reconstruction device according to claim 1 characterized by a funnel-shaped tube (24).

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