Patent Application
20230404805
Not Applicable.
Not Applicable.
Not Applicable.
The invention generally relates to a tissue-augmented corneal inlay surgery technique. More particularly, the invention relates to a tissue-augmented corneal inlay surgery technique where a corneal inlay is implanted under a corneal flap or in a pocket in order to supplement a thickness of the cornea.
Corneal scarring is a major cause of blindness, especially in developing countries. There are various causes for corneal scarring, which include: bacterial infections, viral infections, fungal infections, parasitic infections, genetic corneal problems, Fuch's dystrophy, and other corneal dystrophies. A corneal transplant is often required if the corneal scarring is extensive, and cannot be corrected by other means. However, there can be major complications associated with a corneal transplant, such as corneal graft rejection wherein the transplanted cornea is rejected by the patient's immune system.
A normal emmetropic eye includes a cornea, a lens and a retina. The cornea and lens of a normal eye cooperatively focus light entering the eye from a far point, i.e., infinity, onto the retina. However, an eye can have a disorder known as ametropia, which is the inability of the lens and cornea to focus the far point correctly on the retina. Typical types of ametropia are myopia, hypermetropia or hyperopia, and astigmatism.
A myopic eye has either an axial length that is longer than that of a normal emmetropic eye, or a cornea or lens having a refractive power stronger than that of the cornea and lens of an emmetropic eye. This stronger refractive power causes the far point to be projected in front of the retina.
Conversely, a hypermetropic or hyperopic eye has an axial length shorter than that of a normal emmetropic eye, or a lens or cornea having a refractive power less than that of a lens and cornea of an emmetropic eye. This lesser refractive power causes the far point to be focused behind the retina.
An eye suffering from astigmatism has a defect in the lens or shape of the cornea converting an image of the point of light to a line. Therefore, an astigmatic eye is incapable of sharply focusing images on the retina.
While laser surgical techniques, such as laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) are known for correcting refractive errors of the eye, these laser surgical techniques have complications, such as post-operative pain and dry eye. Also, these laser surgical techniques cannot be safely used on patients with corneas having certain biomechanical properties. For example, corneal ectasia may occur if these laser surgical techniques are applied to patients having thin corneas (e.g., corneas with thicknesses that are less than 500 microns).
Therefore, what is needed is a method for corneal transplantation that reduces the likelihood that the implanted cornea will be rejected by the patient. Moreover, a method is needed for corneal transplantation that is capable of preserving the clarity of the transplanted cornea. Furthermore, there is a need for a method of corneal transplantation that reduces the likelihood that the transplanted cornea will be invaded by migrating cells. Also, what is needed is a method for corneal lenslet implantation for modifying the cornea to better correct ametropic conditions. In addition, a method is needed for corneal lenslet implantation that prevents a lens implant from moving around inside the cornea once implanted so that the lens implant remains centered about the visual axis of the eye. Further, what is needed is a method for intracorneal lens implantation for modifying the cornea to better correct ametropic conditions.
In addition, numerous corneal diseases affect the clarity of the cornea necessitating partial or full thickness corneal replacement. These diseases are generally inherited affecting the cornea but no other organs. The disorders can involve one part of the cornea, but subsequently spread to the neighboring layers. Among the genetic disease involving corneal endothelial cells are Fuchs endothelial dystrophy, hereditary endothelial posterior polymorphic dystrophy, etc. causing damage to the corneal endothelial cells which prevent flooding of the cornea with aqueous fluid and producing the cloudiness of the normally transparent corneal stroma. Other genetic diseases involve the corneal stroma, such as granular corneal dystrophy, macular corneal dystrophy, Schneider crystalline dystrophy, and lattice corneal dystrophy, etc. all blocking or distorting the light that passes through the cornea on way to reach the sensory retina. Others conditions, such as keratoconus and keratoglobus, affect the mechanical stability of the cornea to resist the intraocular pressure. With time the cornea expands and can rupture without a surgical intervention of a corneal transplantation. The other genetic diseases affect the anterior layer of the cornea, the bowman layer of the cornea or the corneal epithelium, such as in Meesmann juvenile epithelial dystrophy, epithelial basement membrane dystrophy, gelatinous drop-like dystrophy, Lisch epithelial corneal dystrophy and Reis-Bucklers corneal dystrophy, and genetic recurrent corneal erosion. However, a number of other conditions can cause damage to the cornea, which results in losing its transparency, e.g., after, injuries, infections, corneal ulcers, or previous cataract surgeries or glaucoma surgeries.
At present about less than 200,000 corneal transplantations are performed each year in the world, but more than 12 million people are in need of corneal transplantation. This discrepancy is created by the need for surgery and unavailability of corneas for transplantation. Some of the reasons stem from the religious beliefs refusing another person's tissue, but most importantly, the retrieved human corneas from human eye banks can be stored only for a limited time which is at present is about 11 days. Even if only a part of the cornea is used for lamellar keratoplasty which requires the corneal stroma, the remaining part of the cornea must be discarded. The use of an animal cornea is not tolerated in humans. In addition, roughly about 10% of human corneal transplants can be rejected by the patients because of the incompatibility of the tissue.
Therefore, there is a further need to reduce the burden of corneal availability by producing synthetic corneal stromal lenslets that at least can be used for partial lamellar transplantation, in patients who have a limited corneal scared stroma after injury and infection. In addition, there is a need to address the growing need in refractive surgery to modify the refractive power of the cornea by a biocompatible refractive partial cornea or lenslet. Obtaining these corneas from the eye bank has been described in previous patents by the present inventor (see e.g., U.S. Pat. Nos. 10,314,690 and 10,583,221, which are hereby incorporated by reference as if set forth in their entirety herein). However, the need for refractive surgery is more than for corneal transplantation. Using the eye bank corneas for creating a lenslet would eliminate their badly needed indications described for patients that require them.
At present, over five million refractive surgeries are done in the world for myopia, hyperopia, astigmatism, keratoconus or keratoglobus eyes. Practically all presently available refractive procedures require ablating a part of the cornea or removing a part of the corneal stroma which thins out these corneas and can potentially lead to ectasia of the corneas, e.g., after the LASIK procedure, etc. leading to the need for a corneal transplantation.
Further, patients above the age of 45 years generally are not considered a candidate for corneal refractive surgery, such as LASIK or SMILE procedures. These two procedures remove a part of the corneal stroma with an excimer laser or femtosecond laser to correct the refractive errors of the eye defocus and astigmatism for the patient to see the far object without the use of glasses.
In young people below the age of 45, the crystalline lens of the eye has the ability to change its shape by ciliary muscles that contracts and relaxes the myriads of microns thick cords called zonules that are attached to the crystalline lens capsule and from another end to the ciliary muscle and suspend the crystalline lens behind the iris, in the posterior chamber of the eye. The circular contraction of the ciliary muscle loosens the zonules and as a result the crystalline lens becomes more convex. This process is called accommodation, by which the near object in front of the eye, such as a newspaper, becomes in focus for the retina to see the letters sharp for reading. This process enables the person to see any object from infinity to about 30 cm sharp as long as the crystalline lens is flexible. However with aging, the crystalline lens becomes more rigid and the eye cannot accommodate to see the near objects sharp.
Since the standard LASIK and SMILE procedures do not correct presbyopia, the ophthalmologist normally recommends the patient wait until the lens becomes a cataract that can be removed and replaced with a multifocal intraocular lens (IOL), which to some degree, provides sharp images at focal points from the eye at various distances.
Though LASIK surgery for presbyopia can convert the refractive power of one eye to see near objects and the other eye to see far objects, the so-called monovision, it is not tolerated by most people and reduces, to some degree, the stereovision. The scleral-based surgery is another attempt to correct presbyopia but it is the least predictable.
Therefore, there is a further need for an ablatable corneal inlay that is capable of simultaneous correction of refractive errors and presbyopia.
The cornea is the transparent dome-shaped tissue of the eye that is exposed to the outside world. The external light coming from an object passes through the cornea, then through the crystalline lens before reaching the retina with its photoreceptors initiating biochemical responses that produces an electrical signal that goes through the optic nerve to the brain and ultimately reaches the visual cortex located in the back of the brain producing the sensation of vision of any object seen. The cornea has a diameter of about 12 mm in horizontal direction and 11 mm vertically. The corneal thickness increases from 500 microns centrally to >650 microns in the periphery. It has an index of refraction of about 1.37 and a curvature of 7.8 mm. The cornea is also the first structure in the eye that acts like a lens creating a dioptric power of about 43.00D. The cornea is made of five layers of tissue and cells. The outer layer of the cornea is composed of non-keratinized epithelial cells. The first layer of the epithelial cells are stratified having microvilli, which is covered with mucin and tear fluid, followed by winged epithelial cells and basal epithelial cells being in contact with the collagenous Bowman membrane separating them from the corneal stroma. The corneal stroma is made of lamellar collagen mostly type I, III, V, VI etc. collagen and keratocytes followed deeper in the corneal stroma by the Descemet Membrane that is made of type IV, VIII collagen and supports hexagonal endothelial cells that build a barrier to flow of aqueous fluid from the anterior chamber of the eye into the corneal stroma. The fluid has to pass through these cells before reaching the corneal stroma. If the endothelial cells are damaged, the uncontrolled aqueous flow causes the corneal stroma to swell and become cloudy and lose its transparency. The lamellar arrangement and the size of the collagen bundles contribute to the transparency of the cornea. The corneal stroma has a cellular component called keratocytes dispersed among the collagen layer that normally are transparent, but can respond to the corneal epithelial cell injury and its cytokines and become active losing their transparency or forming scar tissue that interferes with vision.
The cornea is endowed with numerous nerves that penetrate the corneal stroma building a sub-epithelial nerve plexus that penetrate the epithelial cells and render the cornea one of the most sensitive parts of the body. Damage to the corneal nerves causes the cornea to lose its sensation affecting a normal tear reflex so that the eye becomes dry with its subsequent side effects, such as inflammation or infection, etc.
The cornea contributes to the majority part of dioptric power needed for the external light to be focused on the retina. The crystalline lens contributes only 1/10% of the total dioptric power. Therefore, the majority of the refractive errors are caused by the corneal aberration. The cornea is also a structure that can be easily modified because of its accessibility without the need of entering the eye cavity, as is the case with all other intraocular surgery, e.g., when the crystalline lens has a cataract or is damaged by a trauma, etc.
Though attempts had been made to correct the shape of the cornea by mechanical means, such as using a knife in radial keratotomy, or the use of microkeratome to perform keratomileusis by freezing and milling the cornea, none gained widespread approval because of the serious damage to the corneal mechanics occurring in radial keratotomy or the difficulty of operation and impreciseness of freezing as a part of the cornea and milling it outside the body and replacing it subsequently over the cornea.
In 1980, Peyman tried ablating the cornea with a CO2 laser in animals to find out if the laser could be used to correct refractive errors of the cornea. Unfortunately, the CO2 laser damaged the corneal surface causing burns and scars. Subsequently, when an excimer laser became available, Peyman and his associates independently evaluated the effect of various excimer lasers on the cornea and found that the laser beam produced by argon fluoride ablated the cornea without burning it. In 1985, for the first time, Peyman filed a patent for a procedure that is now known as LASIK (Laser-assisted in situ keratomileusis, U.S. Pat. No. 4,840,175, which is hereby incorporated by reference as if set forth in its entirety herein) in which a corneal flap was created and corneal stromal ablation was done after exposure of the corneal stroma and the corneal flap was replaced over the treated area, contributing to rapid recovery of the vision.
In order for the inlays to be better tolerated inside the corneal pocket, Peyman developed a method for combining implantation of an inlay with the crosslinking of the surrounding corneal tissue to create a space that would not come in contact with the inlay to cause rejection or creating an immune privileged space. However, implantation of a corneal inlay, though tolerated by the body required some time for the visual acuity to recover. Since all inlays are produced without the corneal endothelial cells or a barrier to prevent rapid flow of fluid in the stroma area, this means that slight exposure of the inlay with a preservative fluid, etc. during the inlay storage or transfer, the inlay swells slightly and loses part of its transparency. Therefore, after implantation of an inlay, recovery of vision takes usually >1-2 weeks or more to become transparent or regain to its normal transparency. This is a long time for the patient to wait for his or her vision to fully recover and would make bilateral surgery not desirable.
Though the LASIK procedure is an accepted procedure, the FDA limited its use for eyes that need less than 7.00 D power that is equal to roughly removing an area of the stroma with the thickness of 70 microns. This decision was made because higher dioptric powers would thin the corneal thickness and could cause the cornea to bulge forward with time due to the intraocular pressure. Thus, the other limitation of LASIK is for corneas <450 micron thickness for the same reason. In addition, children would not qualify because the eyes would grow with time and potentially need repeated surgery, which would thin out the cornea further and the operation is irreversible.
The implantation of an inlay and correction of refractive error would solve all these problems. However, as mentioned it would take some time for the inlay or the cornea to become completely transparent.
Therefore, there has been a need for a technology that provides all the benefits of ablating a corneal stroma, as is done with the LASIK procedure, but with a modified corneal inlay over the corneal stroma so as to create immediate transparency of the central cornea for the enabling a patient to see immediately after surgery, as in LASIK, without taking too much tissue from the cornea in patients, such as after LASIK in high myopia patients, or those with keratoconus, or hyperopia, etc., which can produce bulging out of the cornea in the postoperative period requiring a full thickness corneal surgery.
Accordingly, the present invention is directed to a tissue-augmented corneal inlay surgery technique that substantially obviates one or more problems resulting from the limitations and deficiencies of the related art.
In accordance with one or more embodiments of the present invention, there is provided a method of corneal implantation with cross-linking. The method comprising the steps of: (i) implanting a corneal inlay into a recipient cornea of an eye of a patient so as to overlie stromal tissue of the recipient cornea; (ii) applying laser energy to a central portion of the corneal inlay and a portion of the stromal tissue of the recipient cornea underneath the corneal inlay so as to modify the refractive power of the eye; (iii) applying a cross-linking solution that includes a photosensitizer to the recipient cornea of the eye of the patient; and (iv) irradiating the corneal inlay and surrounding corneal tissue so as to activate cross-linkers in the corneal inlay and the surrounding corneal tissue, and thereby cross-link the corneal inlay and the surrounding corneal tissue to prevent an immune response to the corneal inlay and/or rejection of the corneal inlay by the patient. In these one or more embodiments, the central portion of the corneal inlay remains clear for the patient without being obstructed by swollen tissue so that the patient is able to see immediately after the corneal inlay surgery.
In a further embodiment of the present invention, prior to implantation of the corneal inlay, the method further comprises the step of: (v) decellularizing and/or damaging the RNA or DNA of the corneal inlay using chemical means, the chemical means for destroying the cellular elements in the corneal inlay are selected from the group consisting of ethanol, glycerol, acids, alkalis, peracetic acid, ammonium hydroxide ionic detergents, sodium dodecyl sulfate, sodium deoxycholate non-ionic detergents, zwitterionic detergents, Triton X-100, benzalkonium chloride, Igepal, genipin, methylene blue, peptide nucleic acids (PNAs), and combinations thereof.
In yet a further embodiment, prior to implantation of the corneal inlay, the method further comprises the steps of: (v) forming a flap in the recipient cornea of the eye so as to expose the stromal tissue of the recipient cornea underlying the flap; (vi) pivoting the flap so as to expose the stromal tissue of the recipient cornea underlying the flap; (vii) implanting the corneal inlay into the recipient cornea of the eye of the patient by inserting the corneal inlay under the flap so as to overlie the exposed stromal tissue of the recipient cornea; and (viii) after applying the laser energy to the central portion of the corneal inlay and the portion of the stromal tissue of the recipient cornea underneath the corneal inlay, covering the corneal inlay with the flap, the corneal inlay being surrounded entirely by the stromal tissue of the recipient cornea.
In still a further embodiment, the step of forming the flap in the recipient cornea of the eye includes cutting the flap using one of: (i) a femtosecond laser and (ii) a mechanical keratome.
In yet a further embodiment, prior to implantation of the corneal inlay, the method further comprises the steps of: (v) forming a pocket in the recipient cornea of the eye of the patient, the pocket being bounded entirely by stromal tissue of the recipient cornea; and (vi) forming a small side incision in the recipient cornea of the eye of the patient, the pocket being accessible through the small side incision in the recipient cornea. In this further embodiment, the step of implanting the corneal inlay into the recipient cornea of the eye of the patient further comprises implanting a preshaped or non-preshaped corneal inlay using an injector into the pocket of the recipient cornea through the small side incision along with a solution containing hyaluronic acid, a low molecular weight heparin, and/or a viscoelastic solution.
In still a further embodiment, the corneal inlay comprises a central pinhole for correcting presbyopia in the eye of the patient, the central pinhole in the corneal inlay being surrounded by a darkened bounding wall.
In yet a further embodiment, the photosensitizer of the cross-linking solution comprises nanoparticles of riboflavin, and wherein the step of irradiating the corneal inlay comprises irradiating the corneal inlay with ultraviolet light.
In still a further embodiment, the laser energy is applied to the corneal inlay using a femtosecond laser and/or an excimer laser so as to modify the refractive power of the corneal inlay for correction of myopia, hyperopia, presbyopia, and/or astigmatism.
In yet a further embodiment, the method further comprises the steps of: (v) after the corneal inlay surgery, applying a medication to the recipient cornea, the medication being selected from the group consisting of a Rock inhibitor, a Wnt inhibitor, an integrin inhibitor, a GSK inhibitor, allopregnanolone, an anti-VEGF, an antibiotic, an anti-viral medication, an anti-fungal medication, a macrolide, and combinations thereof.
In still a further embodiment, the corneal inlay is formed from an animal cornea.
In yet a further embodiment, the corneal inlay is formed from a human eye bank cornea.
In still a further embodiment, the step of applying the laser energy further comprises ablating the corneal inlay using an excimer laser or a femtosecond laser under the control of a Shack-Hartmann wavefront system and a data processing device so as to modify the corneal inlay to the desired refractive power so that the corneal inlay corrects refractive error of the eye as desired for hyperopia, myopia, astigmatism, or presbyopia after its implantation.
In yet a further embodiment, prior to implantation of the corneal inlay, the method further comprises the step of: (v) cutting and/or shaping the corneal inlay to a desired diameter and/or thickness using a trephine, a femtosecond laser, or an excimer laser so as to modify a refractive power of the corneal inlay and form a central pinhole.
In still a further embodiment, the recipient cornea of the eye of the patient is a human cornea.
In yet a further embodiment, the recipient cornea of the eye of the patient is an animal cornea.
In still a further embodiment, the corneal inlay is a molded corneal inlay or a 3-D printed corneal inlay.
It is to be understood that the foregoing general description and the following detailed description of the present invention are merely exemplary and explanatory in nature. As such, the foregoing general description and the following detailed description of the invention should not be construed to limit the scope of the appended claims in any sense.
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Throughout the figures, the same elements are always denoted using the same reference characters so that, as a general rule, they will only be described once.
A first illustrative embodiment of a corneal transplant procedure with a cross-linked cornea is shown in
Referring initially to
In
In the illustrative embodiments described herein (i.e., as depicted in
In addition to Riboflavin, other suitable cross linking agents are low carbon carbohydrates, such as pentose sugar (e.g., ribose) or hexose sugar (e.g., glucose), or complex carbohydrates. Other crosslinking agents may include Transaminidases, transglutaminases or a naturally-derived cross-linker named malic acid derivative (MAD) concentrations higher than 30 mM, commercially available cross-linkers such as 1-ethyl-3-(3(′-dimethylaminopropyl) carbodiimide (EDC), or ethyl-3(3-dimethylamino) propyl carbodiimide (EDC), etc. The cross-linking may also be done postoperatively by the application of other crosslinking agents, such as Triglycidylamine (TGA) synthesized via reacting epichlorhydrin and a carbodiimide, or the oxidized glycogen hexoses. The ribose, glucose and similar agents may penetrate the cornea easily using drops, gel, or the slow release mechanisms, nanoparticle, microspares, liposome sets. In addition, the crosslinkers may be delivered with Mucoadhesives.
In one or more embodiments, all or part of the donor cornea is cross-linked. Also, in one or more embodiments, a very high concentration of Riboflavin may be used because the in vitro cross-linking process may be stopped whenever needed prior to the transplantation of the donor cornea in the host eye. In addition, the power of the ultraviolet (UV) laser may also be increased so as to cross-link the tissue of the donor cornea faster. The use of a high concentration of Riboflavin, and the increasing of the ultraviolet (UV) laser power, are not possible during an in vivo cross-linking procedure because the aim of such an in vivo procedure is to protect the cells of the host cornea. Also, the in vivo process cannot be controlled as efficiently as in the vitro crosslinking of the corneal transplant.
In one or more embodiments, the donor cornea may be extracted from a human cadaver, or the cornea may be reconstructed as known in tissue engineering in vitro and three-dimensionally (3D) printed. Cross-linking of a culture-grown cornea eliminates the cellular structure inside the cornea. If needed again, the healthy corneal endothelium of the patient may be grown in vitro for these tissues by placing them on the concave surface of the cornea and encouraging their growth under laboratory control conditions prior to the transplantation.
In the embodiments where the donor cornea is tissue culture grown, the cornea may be formed from mesenchymal fibroblast stem cells, embryonic stem cells, or cells derived from epithelial stem cells extracted from the same patient, or a mixture of these cells. Using known tissue culture techniques, the cells may produce a transparent corneal stroma. This culture-grown corneal stroma will not have a corneal epithelium or a corneal endothelium. Thus, it eliminates the complexity of developing a full thickness cornea in the tissue culture. This stromal transplant may be used as a lamellar or partial thickness replacement of the existing host cornea. This transplant may also be used to augment or add to the thickness of the host cornea. This transparent corneal stroma may be transplanted either prior to, or after being cross-linked using various cross-linking methods.
In one or more embodiments, the cross-linked donor cornea may be sized and precisely cut with a femtosecond laser to the desired shape and curvature to replace the removed host cornea so that the refractive errors of the recipient are also automatically corrected with the cross-linked cornea.
Now, referring to
In one or more embodiments, the donor cornea may be shaped and cut with the femtosecond laser prior to the cross-linking thereof so as to replace part or all of the recipient cornea which is cut with the femtosecond laser. In these one or more embodiments, the entire donor and host cornea together may be cross-linked with Riboflavin and UV radiation. These procedures may also be performed on a culture-grown transplant cornea.
Then, as shown in
In one or more embodiments, a biodegradable adhesive is used in a corneal transplantation procedure with the cross-linked donor cornea 20 described above, or with a non-cross-linked corneal transplant. In these one or more embodiments, the biodegradable adhesive obviates the need for a suture in the corneal transplant procedure. Sutures generally distort the surface of the cornea and can produce an optically unacceptable corneal surface. Also, the use of the biodegradable adhesive obviates the need for glues requiring exothermic energy. Glues that use an exothermic effect, such as Fibronectin, need thermal energy to activate their adhesive properties. This thermal energy, such as that delivered by a high-powered laser, produces sufficient heat to coagulate the Fibronectin and the tissue that it contacts. Any thermal effect on the cornea produces: (i) corneal opacity, (ii) tissue contraction, and (iii) distortion of the optical surface of the cornea. The tissue adhesion created by these glues, including Fibronectin or fibrinogen, is flimsy and cannot withstand the intraocular pressure of the eye.
In fact, sutures are superior to these types of adhesives because the wound becomes immediately strong with sutures, thereby supporting the normal intraocular pressure of between 18 and 35 mmHg. In contrast to the use of a suture in which distortion that is caused by suture placement can be managed by cutting and removing the suture, the distortion caused by the coagulated corneal tissue cannot be corrected.
Other glues, such as cyanoacrylate, become immediately solid after coming into contact with the tissue or water. These glues produce a rock-hard polymer, the shape of which cannot be controlled after administration. Also, the surface of the polymer created by these glues is not smooth. Thus, the eyelid will rub on this uneven surface, and the uneven surface scratches the undersurface of the eyelid when the eyelid moves over it. In addition, the cyanoacrylate is not biodegradable or biocompatible. As such, it causes an inflammatory response if applied to the tissue, thereby causing undesirable cell migration and vascularization of the cornea.
Thus, by using a biocompatible and absorbable acrylate or other biodegradable glues that do not need exothermic energy for the process of adhesion (i.e., like fibronectin or fibrinogen), one is able to maintain the integrity of the smooth corneal surface. In one or more embodiments, the biocompatible and biodegradable adhesive may be painted only at the edges of the transplant prior to placing it in the host or diseased cornea. In these embodiments, the biocompatible and biodegradable adhesive only comes into contact with the host tissue at the desired predetermined surface to create a strong adhesion. The adhesion may last a few hours to several months depending on the composition of the molecule chosen and the concentration of the active component.
Other suitable biodegradable adhesives or glues that may be used in conjunction with the transplant include combinations of gallic acid, gallic tannic acid, Chitosan, gelatin, polyphenyl compound, Tannic Acid (N-isopropylacrylamide (PNIPAM), and/or Poly(N-vinylpyrrolidone) with polyethylene glycol (PEG). That is, polyethylene glycol (PEG) may be mixed with any one or plurality of gallic acid, gallic tannic acid, Chitosan, gelatin, polyphenyl compound, Tannic Acid (N-isopropylacrylamide (PNIPAM), and Poly(N-vinylpyrrolidone), so as to form a molecular glue. These adhesives are suitable for the use on the cornea because they create a tight wound that prevents leakage from the corneal wound and maintain the normal intraocular pressure shortly after their application and also do not distort the wound by causing traction on the tissue.
In one or more embodiments, the donor cornea may be temporarily sutured to the host cornea by only a few single sutures to the host cornea. Then, the sutures may be removed immediately after donor cornea is fixed to the host cornea with a suitable adhesive.
A second illustrative embodiment of a corneal transplant procedure with a cross-linked cornea is shown in
Referring initially to
Next, referring to
Finally, as shown in
After the cross-linked donor corneal portion 20′ is implanted into the eye 10′ of the patient, a portion of the cornea 16′ may be ablated so as to change the refractive properties of the eye (e.g., to give the patient perfect or near perfect refraction). The ablation of the portion of the cornea 16′ may be performed using a suitable laser 34, such as an excimer laser. The ablation by the laser causes the ablated tissue to essentially evaporate into the air. Also, the ablation of the portion of the cornea 16′ may be done intrastromally, as with LASIK (laser-assisted in situ keratomileusis), or on the surface of the cornea, as with PRK (photorefractive keratectomy). The ablation may be performed a predetermined time period after the corneal transplantation so as to enable the wound healing process of the recipient's cornea to be completed. It is to be understood that the ablation, which follows the corneal transplantation, may be performed in conjunction with any of the embodiments described herein.
It is also to be understood that, in some alternative embodiments, the ablation may be performed prior to the transplantation of the donor cornea, rather than after the transplantation of the donor cornea. For example, in one or more alternative embodiments, a lenticle may be precisely cut in the tissue of a culture-grown stroma of a donor cornea by using a femtosecond laser so that when implanted into the host cornea, it corrects the residual host eye's refractive error.
A third illustrative embodiment of a corneal transplant procedure with a cross-linked cornea is shown in
Referring initially to
Next, referring to
Finally, as shown in
It is to be understood that the scarred and/or diseased corneal portion 16a″ that is removed from the cornea 16″ may also be replaced with stroma stem cells or mesenchymal stem cells, which can be contained in a medium, and then injected in the internal cavity previously occupied by the scarred and/or diseased corneal tissue 16a″.
In one or more embodiments, mesenchymal stem cells also may be injected inside the donor cornea before or after transplantation. In addition, in one or more embodiments, daily drops of a Rho Kinase inhibitor may be added to the host eye after the surgery. The use of a medication, such as a Rho Kinase inhibitor, with the stem cells will encourage stem cell proliferation.
A fourth illustrative embodiment of a corneal transplant procedure with a cross-linked cornea is shown in
Referring initially to
In
Next, referring to
Finally, as shown in
An illustrative embodiment of a corneal lenslet implantation procedure with a cross-linked cornea is shown in
Now, with reference to
In
Finally, as shown in
Another illustrative embodiment of a corneal lenslet implantation procedure with a cross-linked cornea is shown in
Initially, in
Then, in
Turning again to
In one embodiment, a three-dimensional (3D) uniform circular, oval, or squared-shaped corneal pocket 116 is cut with a femtosecond laser and the tissue inside the pocket is removed to produce a three-dimensional (3D) pocket 116 to be cross-linked with riboflavin and implanted with a prepared implant.
After the pocket 116 is formed using the spatula 118, a photosensitizer is applied inside the three-dimensional pocket 116 so that the photosensitizer permeates the tissue surrounding the pocket 116 (see
Next, turning to the illustrative embodiment of
Alternatively, as shown in
Now, with reference to
In the illustrative embodiment, the irradiation of the cornea 112 using the ultraviolet (UV) radiation 122 only activates cross-linkers in the portion of the stromal tissue surrounding the three-dimensional pocket 116, and only kills the cells in the portion of the tissue surrounding the pocket 116, so as to leave only a thin layer of cross-linked collagen to prevent an immune response and rejection of the lens implant 128 and/or encapsulation by fibrocytes, while preventing post-operative dry eye formation. In addition to preventing encapsulation of the lens implant 128 by fibrocytes, the cross-linking of the stromal tissue surrounding the pocket 116 also advantageously prevents corneal haze formation around the lens implant 128. That is, the cross-linking of the stromal tissue surrounding the lens implant 128 prevents formation of myofibroblast from surrounding keratocytes, which then convert gradually to fibrocytes that appear as a haze, and then white encapsulation inside the cornea, thereby causing light scattering in front of the patient's eye.
As shown in
In one or more embodiments, the lens implant or inlay 128 may be prepared ahead of time with known techniques, wherein the inlay 128 may be coated with a biocompatible material, such as collagen, elastin, polyethylene glycol, biotin, streptavidin, etc., or a combination thereof. The inlay 128 and the coating may be cross-linked with a photosensitizer or cross-linker, such as riboflavin, prior to being implanted into the pocket 116 in the cornea 112 of the eye.
In another embodiment, the lens implant or inlay 128 may be silicone, methacrylate, hydroxyethylmethacrylate (HEMA), or any other biocompatible transparent material, or a mixture thereof. The lens implant or inlay 128 also may be coated with materials, such as collagen or elastin, and may have a desired thickness of from 2 microns to 70 microns or more.
In yet another embodiment, the lens implant or inlay 128 is formed from an eye bank cornea, or a cross-linked eye bank cornea, etc. In general, there is a tremendous paucity of normal cadaver corneas for total or partial implants, such as for a corneal transplant of a corneal inlay. Because all the cellular elements are killed during the crosslinking of the corneal inlay, and because the corneal collagen is cross-linked and denatured, the remaining collagenous elements are not immunogenic when implanted inside the body or in the cornea of a patient. Advantageously, the prior cross-linking of the organic material, such as in the cadaver cornea, permits transplantation of the corneal inlay from an animal or human cornea or any species of animal to another animal or human for the first time without inciting a cellular or humoral response by the body, which rejects the inlay. Thus, cross-linking transparent cadaveric tissue for corneal transplantation, or as an inlay to modify of the refractive power of the eye, is highly beneficial to many patients who are on the waiting list for a corneal surgery. In addition, the surgery may be planned ahead of time without necessitating the urgency of the surgery when a fresh cadaver eye becomes available. In one or more embodiments, the collagens may be driven from the animal cornea, and cross-linked. Also, in one or more embodiments, the implant or inlay 128 may be made of cross-linked animal cornea or human cornea that is cut using a femtosecond laser to any desired shape and size, and then ablated with an excimer laser or cut with a femtosecond laser to a have a desired refractive power.
For example, as shown in
In still another embodiment, as depicted in
In yet another embodiment, after the implantation of an intraocular lens, the remaining refractive error of the eye may be corrected by the implantation of a lens implant or inlay 128 in the cross-linked pocket 116 of the cornea 112, thereby eliminating the need for entering the eye cavity to replace the original intraocular lens.
In still another embodiment, the remaining refractive error of the eye is corrected after an intraocular lens implantation by placing an inlay 128 on the surface of the cornea 112 of the patient while the shape of the cornea 112 is corrected with an excimer laser and wavefront optimized technology so that the patient is provided instant input on its effect on his or her vision. In this embodiment, an inlay similar to a contact lens is placed on the cornea 112 that, after correction, matches the desired refractive correction of the eye, and then, subsequently, the inlay 128 is implanted inside the cross-linked corneal pocket 116.
In yet another embodiment, the implant or inlay 128 may be ablated with an excimer laser for implantation in the cross-linked pocket 116, or after cross-linking the exposed corneal stroma in LASIK surgery.
In still another embodiment, a small amount of hyaluronic acid or a viscous fluid is injected into the pocket 116 prior to the implantation of the implant or inlay 128 so as to simplify the insertion of the implant or inlay 128 in the corneal pocket 116.
In yet another embodiment, the implant or inlay 128 is prepared having four marking holes of 0.1-2 millimeter (mm) in diameter in the inlay periphery at an equally sized distances so that the implant 128 may be rotated with a hook, if desired, after the implantation as needed to match the axis of an astigmatic error of the eye during the surgery as measured simultaneously with a wavefront technology system, such as an Optiwave Refractive Analysis (ORA) system or Holos® system, which are commercially available for measurement of astigmatism or its axis.
In still another embodiment, the implant or inlay 128 is located on the visual axis and may provide 1 to 3 times magnification for patients whose macula is affected by a disease process needing magnifying glasses for reading, such as in age-related macular degeneration, macular edema, degenerative diseases of the retina, etc. Because these eyes cannot be used normally for reading without external magnifier glasses, providing magnification by a corneal implant to one eye assists the patients in being able to read with one eye and navigate the familiar environment with their other eye.
In yet another embodiment, the surface of the cornea 112 is treated after surgery in all cases daily with an anti-inflammatory agent, such as steroids, nonsteriodal anti-inflammatory drugs (NSAIDs), immune-suppressants, such as cyclosporine A or mycophenolic acid, anti-proliferative agents, antimetabolite agents, or anti-inflammatory agents (e.g., steroids, NSAIDS, or antibiotics etc.) to prevent inflammatory processes after the corneal surgery, inlay implantation or crosslinking, while stabilizing the integrity of the implant 128 and preventing future cell growth in the organic implant or the adjacent acellular corneal tissue. In this embodiment, the medication is injected in the corneal pocket 116 along with the implantation or the implant 128 is dipped in the medication first, and then implanted in the cross-linked corneal pocket 116.
In still another embodiment, a cross-linked corneal inlay is placed over the cross-linked corneal stroma after a LASIK incision, and is abated to the desired size with an excimer laser using a topography guided ablation. By means of this procedure, the refractive power of the eye is corrected, while simultaneously providing stability to an eye prone to conceal ectasia postoperatively after a LASIK surgery. Then, the LASIK flap is placed back over the implant.
Yet another illustrative embodiment of a corneal lenslet implantation procedure with a cross-linked cornea is shown in
Initially, in
Then, in
In an alternative embodiment of the corneal lenslet implantation procedure, three (3) sequential cuts may be made in the stromal portion of the cornea 212 of the eye 210 using a femtosecond laser in order to form the pocket. First, a lower circular cut or incision centered about the visual axis (i.e., a lower incision with the patient in a supine position) is made using the femtosecond laser. Then, a second vertical cut is made above the lower incision using the femtosecond laser to form the side(s) of a circular cutout portion. Finally, a third square or circular cut (i.e., an upper incision) is made above the vertical cut using the femtosecond laser. In the illustrative embodiment, the lower incision is parallel to the upper incision, and the vertical cut extends between lower incision and the upper incision. In this alternative embodiment, the three-dimensional circular stromal tissue cutout portion bounded by the lower incision on the bottom thereof, the vertical cut on the side(s) thereof, and the upper incision on the top thereof is removed from the cornea 212 of the eye 210 using a pair of forceps. A cavity formed by the upper incision facilitates the removal of the three-dimensional circular stromal tissue cutout portion. As described above, the third cut or incision formed using the femtosecond laser may be an upper circular cut that is larger than the lower circular cut, rather than an upper square cut that is larger than the lower circular cut.
Turning to
Next, turning again to the illustrative embodiment of
Now, with combined reference to
Advantageously, the lens implant 220 of the aforedescribed illustrative embodiment always remains perfectly centered around the visual axis 214 of the eye 210, and will not move because it is disposed within the circular recess at the bottom of the pocket 216. As explained above, the lens implant 220 may be formed from an organic material, synthetic material, polymeric material, and combinations thereof. The lens implant 220 may replace either a diseased tissue or create a new refractive power for the eye 210, as explained hereinafter.
In the illustrative embodiment, the lens implant 220 may correct the refractive errors of the eye 210. The refractive error correction may be done by the lens implant 220 having a curvature that changes the corneal surface of the cornea 212. Alternatively, the lens implant 220 may have a different index of refraction that corrects the refractive power of the cornea 212. In the illustrative embodiment, the lens implant 220 may have the appropriate shape to reshape the cornea 212 or the dioptric power to nullify the remaining spheric or astigmatic error of the eye. More particularly, in one or more embodiments, the lens implant 220 may have one of: (i) a concave anterior surface to correct myopic refractive errors (i.e., a minus lens for correcting nearsightedness), (ii) a convex anterior surface to correct hyperopic refractive errors (i.e., a plus lens for correcting farsightedness), or (iii) a toric shape to correct astigmatic refractive errors.
In the illustrative embodiment, the irradiation of the cornea 212 using the ultraviolet (UV) radiation 224 only activates cross-linkers in the portion of the stromal tissue surrounding the three-dimensional pocket 216, and only kills the cells in the portion of the tissue surrounding the pocket 216, so as to leave only a thin layer of cross-linked collagen to prevent an immune response and rejection of the lens implant 220 and/or encapsulation by fibrocytes, while preventing post-operative dry eye formation. In addition to preventing encapsulation of the lens implant 220 by fibrocytes, the cross-linking of the stromal tissue surrounding the pocket 216 also advantageously prevents corneal haze formation around the lens implant 220. That is, the cross-linking of the stromal tissue surrounding the lens implant 220 prevents formation of myofibroblast from surrounding keratocytes, which then convert gradually to fibrocytes that appear as a haze, and then white encapsulation inside the cornea, thereby causing light scattering in front of the patient's eye.
It is readily apparent that the aforedescribed corneal transplant procedures offer numerous advantages. First, the implementation of the aforedescribed corneal transplant procedures reduces the likelihood that the implanted cornea will be rejected by the patient. Secondly, the aforedescribed corneal transplant procedures enable the clarity of the transplanted cornea to be preserved. Finally, the aforedescribed corneal transplant procedures reduce the likelihood that the transplanted cornea will be invaded by migrating cells, such as migrating cells that might initiate an immune response such as macrophage, lymphocytes or leucocytes or vascular endothelial cells. These types of migrating cells are discouraged by the cross-linked corneal collagen which does not provide an easily accessible tissue to invade. In addition, the use of abovedescribed tissue adhesives reduces the surgical procedure significantly. Moreover, the aforedescribed corneal lenslet implantation procedures modify the cornea so as to better correct ametropic conditions. Furthermore, the corneal lenslet implantation procedures described above prevent the lens implant from moving around inside the cornea once implanted, thereby ensuring that the lens implant remains centered about the visual axis of the eye.
With reference to the embodiment of
In
After the pocket 302 is cut using the femtosecond laser or mechanical keratome, a photosensitizer is applied inside the pocket so that the photosensitizer permeates the tissue bounding the pocket 302. The photosensitizer facilitates the cross-linking of the tissue bounding the pocket 302. In the illustrative embodiment, the photosensitizer is injected with a needle inside the stromal pocket without lifting the anterior corneal stroma so as to cover the internal surface of the corneal pocket 302 (e.g., as shown in
Next, turning to the illustrative embodiment of
Now, with reference to
In the illustrative embodiment, the irradiation of the cornea 300 using the ultraviolet (UV) radiation 304 only activates cross-linkers in the portion of the stromal tissue bounding the pocket 302, and only kills the cells in the portion of the tissue bounding the pocket 302, so as to leave only a thin layer (e.g., between 20 and 30 microns) of cross-linked collagen to prevent rejection of the lens implant 308 and/or encapsulation by fibrocytes, while preventing post-operative dry eye formation. In addition to preventing encapsulation of the lens implant 308 by fibrocytes, the cross-linking of the stromal tissue bounding the pocket 302 also advantageously prevents corneal haze formation around the lens implant 308. That is, the cross-linking of the stromal tissue surrounding the lens implant 308 prevents formation of myofibroblast from surrounding keratocytes, which then convert gradually to fibrocytes that appear as a haze, and then white encapsulation inside the cornea, thereby causing light scattering in front of the patient's eye.
In one or more further embodiments, after the lens implant 308 has been inserted into the pocket 302, an additional amount of photosensitizer (e.g., an additional amount of riboflavin) is injected into the pocket 302, and the cornea 300 is irradiated an additional time so as to further stiffen stromal tissue of the cornea and expand the area of acellular collagenous stromal tissue surrounding the lens implant 308 to prevent rejection of the lens implant 308 and/or encapsulation of the lens implant 308 by fibrocytes, while preventing post-operative dry eye formation. That is, the area of acellular collagenous stromal tissue surrounding the lens implant 308 is able to be cross-linked repeatedly through the use of additional riboflavin injections so that the area of intrastromal crosslinking may be extended, and to prevent implant rejection and cellular fibrosis formation at any time after the initial procedure. This additional cross-linking still leaves the anterior stromal nerves intact and uncross-linked so as to not produce dry eye formation.
Referring again to the illustrative embodiment of
In the illustrative embodiment, the laser beam(s) emitted by the two-photon or multi-photon laser 312 heats up the lens implant 308, and thereby modifies the index of refraction of the lens implant 308 (i.e., it creates a more positive or negative lens). Because a two-photon or multi-photon laser 312 comprises two or more laser beams that come together at the focal point of the laser, less energy is passing through the anterior corneal tissue disposed in front of the lens implant 308. Thus, advantageously, in the illustrative embodiment, the two-photon or multi-photon laser 312 does not damage the surface of the cornea or the corneal tissue anteriorly disposed relative to the lens implant 308. In the illustrative embodiment, the two-photon or multi-photon laser 312 modifies the interior of the lens implant 308 (i.e., by modifying its refractive index), but it does not modify the surface of the lens implant 308 or the corneal tissue disposed anteriorly disposed relative to the lens implant 308. In the illustrative embodiment, the laser beam(s) of the two-photon or multi-photon laser 312 may have a wavelength between about 700 nanometers and about 1100 nanometers (or between 700 nanometers and 1100 nanometers). In the illustrative embodiment, the two-photon or multi-photon laser 312 does not require a photosensitizer, and the laser beams emitted thereby may penetrate between 100 and 400 microns into the interior of the cornea.
In one or more embodiments, prior to the application of the laser energy to the lens implant 308 in the pocket 302 by the two-photon or multi-photon laser 312, a virtual model of the lens implant 308 is generated, and the two-photon or multi-photon laser 312 is focused in accordance with the virtual model. In particular, a specially programmed data processing device (i.e., a specially programmed computing device or computer) is used to generate a virtual model of the lens implant 308 so that a new index of refraction of the lens implant 308 at the focal point of the two-photon or multi-photon laser 312 is capable of being determined prior to the application of the two-photon or multi-photon laser 312. Then, the specially programmed data processing device (i.e., a specially programmed computing device or computer) is used to focus the two-photon or multi-photon laser 312 non-invasively outside the eye in accordance with the virtual model generated for the lens implant 308.
In one or more further embodiments, a femtosecond laser, a two-photon laser, or a multi-photon laser may be used to apply laser energy to the lens implant 308 in the pocket 302 in order to increase the index of refraction of a particular area of the lens implant (e.g., by creating a prismatic line on the surface of the lens or inside of the lens), and thereby convert the lens implant from a monofocal lens to a bifocal lens or trifocal lens. In these further embodiments, the particular area of the lens implant 308 that the index of refraction is increased may comprise one of: (i) an area slightly below the cornea or the central visual axis of the eye, (ii) a central area centrally located on the central visual axis of the eye, and (iii) a peripheral area circumscribing the central visual axis of the eye. For example, in one embodiment, the particular area of the lens implant 308 that is modified may be 2-3 mm in diameter to correct presbyopia in an older person. The index of refraction of the particular area of the lens implant 308 may be modified to correct myopic refractive errors (i.e., nearsightedness), hyperopic refractive errors (i.e., farsightedness), or astigmatic refractive errors. Because the lens implant 308 can be removed from the eye (e.g., using a spatula), and replaced, the entire refractive error correction process described above can be reversible, and is capable of being repeated.
Also, in one or more further embodiments, a femtosecond laser, a two-photon laser, or a multi-photon laser may be used to apply laser energy to the lens implant 308 in the pocket 302 in order to create diffractive portions within the lens implant 308, thereby resulting in a bifocal lens comprising both refractive and diffractive lens portions.
In the method described above, as illustrated in
In a second illustrative embodiment of the intracorneal lens implantation procedure with the cross-linking of the cornea, a lens implant is soaked in a crosslinking solution prior to be inserted into the eye of the patient. As will be described in further detail hereinafter, this method generally includes soaking a lens implant in a crosslinking solution, forming a pocket in the cornea of an eye, inserting the lens implant in the pocket, cross-linking the interior stroma of the cornea, and then applying laser energy to the lens implant in the pocket using a laser to correct refractive errors of the lens implant and/or the eye in a non-invasive manner. As in the first illustrative embodiment of the intracorneal lens implantation procedure explained above, no flap is formed in the cornea of the eye. Also, the front surface of the cornea is not ablated using a PRK procedure.
Initially, in the second illustrative embodiment of the intracorneal lens implantation procedure, a lens implant is soaked in a cross-linking solution held in a container prior to its insertion into a corneal pocket in the eye so that the lens implant is pre-coated with the cross-linking solution thereon. The lens implant has a predetermined shape for changing the refractive properties of an eye, and is flexible and porous so that fluids (e.g., oxygen, electrolytes, glucose, etc.) are able to freely pass through the lens implant. In the second illustrative embodiment, the lens implant may comprise a hybrid lens implant as described above with regard to the first illustrative embodiment, or may comprise any of the other characteristics described above with regard to the lens implant 308. The coated surface of the hybrid lens implant may be organic and hydrophilic, and may formed using a desired thickness that can be cross-linked with UV light and riboflavin before or after its implantation. Also, in the second illustrative embodiment, the cross-linking solution may comprise a photosensitizer in the form of riboflavin, and/or a liquid suspension having nanoparticles of riboflavin disposed therein. Preferably, the cross-linker has between about 0.1% riboflavin to about 100% riboflavin therein (or between 0.1% and 100% riboflavin therein).
Next, in the second illustrative embodiment of the intracorneal lens implantation procedure, a pocket is formed in the cornea of the eye. The formation of the corneal pocket in the cornea of the eye allows one to gain access to the tissue bounding the pocket (i.e., the interior stromal tissue bounding the pocket). In particular, in the second illustrative embodiment, the pocket is formed by making an intrastromal incision in the cornea of the eye either by using a femtosecond laser (i.e., the incision is cut in the cornea using the laser beam(s) emitted from the femtosecond laser) or by using a mechanical keratome (e.g., a mechanical microkeratome).
After the pocket is formed in the cornea of the eye, the lens implant with the photosensitizer provided thereon (e.g., riboflavin) is inserted inside the pocket so that the photosensitizer permeates at least a portion of the tissue bounding the pocket. In particular, in the illustrated embodiment, the lens implant is inserted into the corneal pocket through a very small incision using a pair of forceps or microforceps. The photosensitizer facilitates the cross-linking of the portion of the tissue bounding the pocket.
Then, shortly after the lens implant with the photosensitizer is inserted inside the pocket, the cornea of the eye is irradiated from the outside using ultraviolet (UV) radiation so as to activate cross-linkers in the portion of the tissue bounding the pocket, and thereby stiffen the cornea, prevent corneal ectasia of the cornea, and kill cells in the portion of the tissue bounding the pocket. In the illustrative embodiment, the ultraviolet light used to irradiate the cornea may have a wavelength between about 370 nanometers and about 380 nanometers (or between 370 nanometers and 380 nanometers). Also, in the illustrative embodiment, only a predetermined anterior stromal portion of the cornea to which the photosensitizer was applied from the lens implant is cross-linked (e.g., only the bounding wall of the corneal pocket), thereby leaving an anterior portion of the cornea and a posterior stromal portion of the cornea uncross-linked. That is, in the illustrative embodiment, the entire corneal area inside the cornea exposed to the cross-linker is selectively cross-linked, thereby leaving the anterior part of the cornea and the posterior part of the stroma uncross-linked. The portion of the cornea without the cross-linker is not cross-linked when exposed to the UV radiation. In an alternative embodiment, the cornea may be irradiated using microwaves as an alternative to, or in addition to being irradiated using ultraviolet (UV) radiation.
In the second illustrative embodiment of the intracorneal lens implantation procedure, the irradiation of the cornea using the ultraviolet (UV) radiation only activates cross-linkers in the portion of the stromal tissue bounding the pocket, and only kills the cells in the portion of the tissue bounding the pocket, so as to leave only a thin layer of cross-linked collagen to prevent rejection of the lens implant and/or encapsulation by fibrocytes, while preventing post-operative dry eye formation. In addition to preventing encapsulation of the lens implant by fibrocytes, the cross-linking of the stromal tissue bounding the pocket also advantageously prevents corneal haze formation around the lens implant. That is, the cross-linking of the stromal tissue surrounding the lens implant prevents formation of myofibroblast from surrounding keratocytes, which then convert gradually to fibrocytes that appear as a haze, and then white encapsulation inside the cornea, thereby causing light scattering in front of the patient's eye.
After the lens implant has been inserted into the pocket in the cornea of the eye, laser energy is applied to the lens implant in the pocket using a laser so as to correct refractive errors of the lens implant and/or the eye in a non-invasive manner. In the second illustrative embodiment, a two-photon or multi-photon laser is used to apply the laser energy to the lens implant in the pocket so as to modify the index of refraction of a discrete internal part of the lens implant in a non-invasive manner, while preventing post-operative dry eye formation. In the second illustrative embodiment, the laser energy applied by the two-photon or multi-photon laser has a predetermined energy level below an optical breakdown power level of the two-photon or multi-photon laser.
As described above with regard to the first illustrative embodiment of the intracorneal lens implantation procedure, prior to the application of the laser energy to the lens implant in the pocket by the two-photon or multi-photon laser, a virtual model of the lens implant may be generated, and the two-photon or multi-photon laser may be focused in accordance with the virtual model. In particular, a specially programmed data processing device (i.e., a specially programmed computing device or computer) is used to generate a virtual model of the lens implant so that a new index of refraction of the lens implant at the focal point of the two-photon or multi-photon laser is capable of being determined prior to the application of the two-photon or multi-photon laser. Then, the specially programmed data processing device (i.e., a specially programmed computing device or computer) is used to focus the two-photon or multi-photon laser non-invasively outside the eye in accordance with the virtual model generated for the lens implant.
In a third illustrative embodiment of the intracorneal lens implantation procedure with the cross-linking of the cornea, the procedure may be performed in a similar manner to that described above with regard to the second illustrative embodiment, except that the laser energy may be applied to the lens implant in the pocket by the laser prior to the irradiation of the cornea, rather than after the irradiation of the cornea as described above in the second embodiment.
In further illustrative embodiments, synthetic lenslets are created from collagen, which is modified in the process of lenslet production and subsequently after implantation, to prevent rejection of these lenslets by the host tissue. In his previous published patents (see e.g., U.S. Pat. Nos. 9,937,033, 10,278,920, 10,314,690, and 10,583,221, which are hereby incorporated by reference as if set forth in their entirety herein), the present inventor described that crosslinking the human corneal implant eliminates the human corneal immune response to the human crosslinked cornea and crosslinking the wall of the host cavity practically eliminates the host's tendency to induce an immune reaction against the implanted tissue. As described in these patents, the host's cells surrounding a corneal cavity are killed by crosslinking and the host corneal collagen in that area is also crosslinked. The crosslinking changes the molecular structure and bounding of the amino acids, peptides, and proteins creating many crosslinked bonds that make the tissue more resilient, while maintaining the transparency of the lenslet and eliminating their immunogenicity since they do not have free molecular attachments. Therefore, practically, one creates an immune privileged space inside the host cornea.
In one embodiment, the synthetic lenslet will have a compensatory refractive surface that modifies the refractive error of the host after its implantation, that is myopia, hyperopia astigmatism, and presbyopia by using either an excimer laser or a femtosecond laser with a Shack-Hartmann sensor and wavefront technology to modify the surface of the lenslet prior to its implantation in the host corneal cavity. In addition, this procedure adds to mechanical stability of the cornea because it is crosslinked.
In one embodiment, crosslinking of the synthetic inlay can be done by one or a combination of crosslinkers, such as riboflavin, xanthine, derivatives Rose Bengal, erythrosin, eosin, and phthalocyanine, porphyrin hypericin, and Rose Bengal and mixtures thereof, or other synthetic dyes, such as porphyrins, 5-aminolevulinic acid, polymeric photosensitizers, using an appropriate wavelength of a laser light.
In one embodiment, the corneal synthetic implant is produced by 3-D printing technology or molding of organic collagen material or a combination collagen with other polymers of group of chitosan, elastin, hyaluronic acid, having an index of refraction of 1.3 building a refractive lenslet of a predetermined shape that corrects the refractive power of an eye having either myopic, hyperopic, astigmatic, or presbyopia or a combination thereof, wherein the synthetic lenslet is implanted in a preformed corneal pocket created with a femtosecond laser where the synthetic lenslet along with a photosensitizer is injected inside the stromal pocket followed by crosslinking the implant and the wall of the corneal stroma by ultraviolet (UV) radiation to prevent rejection of the implant and provide resiliency to the cornea and correct refractive error of the eye.
In one embodiment, a slurry fluid containing collagen at a concentration of 1%-98% w/w or 10%-30% or 15% w/w to 50% w/w or 50% to 80% w/w or combined with other polymers, such chitosan or elastin or hyaluronic acid, etc. and a photosensitizer, such as riboflavin or Rose Bengal at concentration of 0.1%-1% injected in a corneal pocket created with a femtosecond laser wherein the synthetic collagen can correct the hyperopic refraction or presbyopia under control of a Shack-Hartmann sensor along with a photosensitizer injected inside the stromal pocket followed by crosslinking the implant and the wall of the corneal stroma by UV radiation using a UV laser at power of 3 mW/cm2 to 20 mW/cm2 for a short period or time of 1 minute to 10 minutes depending on the power of the UV laser and the concentration of the riboflavin to solidify the gel to correct hyperopia or presbyopia under the control of a Shack-Hartmann sensor and to prevent rejection of the crosslinked collagen and provide resiliency to the cornea.
In one embodiment, the corneal synthetic lenslet is produced by injection printing technology under control of a Shack-Hartmann sensor and optical coherence tomography (OCT), having a composition of organic collagen type I or a combination collagen 15% to 30% w/w or along with other polymers of group of chitosan, elastin, hyaluronic acid of less than 3% w/w and riboflavin concentration of 0.1-3% w/w or 1% w/w to 5% w/w or more is injected inside a 3-D printer unit to create a synthetic refractive lenslet which is crosslinked partially with UV radiation and injected in a corneal pocket with riboflavin and crosslinked the synthetic lenslet and the wall of the corneal stroma with the UV radiation, wherein the synthetic lenslet corrects the hyperopic, myopia, or astigmatic refraction or presbyopia and OCT.
In one embodiment, synthetic implant is made of a collagen material having a concentration of 15% w/w and other polymeric compounds are less than 1% w/w to 5% w/w or more.
In one embodiment, the synthetic lenslet contains collagen and polyethylene glycol stabilized chitosan in addition to collagen type I with some Type III collagen.
In one embodiment, the container or the mold has a predetermined surface that produces either a convex or concave or an astigmatic lenslet (see
In one embodiment, the mold is from 2-14 millimeters (mm) in diameter or more.
In one embodiment, the lenslet can have a thickness of 50 microns to 2 mm or more.
In one embodiment, the container has a surrounding lip which has a vertical, 90 degree or 45 degree or more tilt to the surface of the mold and extends beyond the bottom surface of the mold to create a circular stable support in which the mold is separated from the horizontally placed smooth surface such as glass (see
In one embodiment, the vertical lip fits in a groove at the edge of the surface of the horizontal back plate (see
In one embodiment, the plate and the lip can be screwed in or out or in another method known in the art, releasing the formed lenslet after it is crosslinked.
In one embodiment, the corneal synthetic implant is produced by 3-D printing technology using collagen type 1 or in combination with type III collagen with or without other polymers, such as chitosan, elastin, hyaluronic acid, having an index of refraction of 1.3 and having short acting photosensitizer carbodiimide and riboflavin is used in building a lenslet of predetermined shape and/or refractive power where the carbodiimide initiate a slight crosslinking without a complete crosslinking, while the addition of riboflavin is activated after 3-D printing with UV radiation to provide a more permanent crosslinking of the lenslet that corrects the refractive power of an eye having a refractive error of myopic, hyperoptic, astigmatic, or presbyopia or a combination thereof, when implanted in a corneal pocket through a small incision made with a femtosecond laser of 1-2 mm in diameter along with 0.1% or more riboflavin solution which crosslinks the implant and the wall of the corneal stroma by UV radiation and prevents rejection of the implant and dry eye formation in the post-operative period by protecting majority of the sub-bowman nerve plexus.
In one embodiment, the two stage crosslinking permits the moderately crosslinked collaged scaffold to pass through the nozzle of the 3-D printer while the activation of the riboflavin with the UV laser subsequently completes the crosslinking of the lenslet and the wall of the corneal pocket to prevent future rejection.
In one embodiment, the lip 438 of the mold has micro holes 439 therein that permits a part of the fluid to escape if a plunger 436 (see
In one embodiment, the shape of the collagen does not change by the crosslinking but converts a part of the collagen to crosslinked collagen scaffold and increases its biomechanical stability.
In one embodiment, the synthetic lenslet is made of mostly collagen type I alone or with some type III collagen as found in the cornea and crosslinked with a photosensitizer, such as riboflavin or Rose Bengal or other crosslinkers and UV radiation. In one embodiment, the lenslet will have a final thickness of 250 microns or less.
In one embodiment, the lenslets 452, 456 are created from +0.1 to 20.00 dioptric power, or alternatively from −0.1 to 20.00 dioptric power, or the lenslet is irradiated with an excimer laser 454, 458 (see
In one embodiment, with reference to
In one embodiment, the front surface of the synthetic implant is flat and the posterior surface is convex or concave as shaped by the mold, but the lenslet is implanted with its refractive surface facing out toward the corneal epithelium and the flat surface of the lenslet lies on the posterior corneal surface of the corneal pocket.
In another embodiment, the synthetic collagen lenslet 460, 464 has a parallel surface which can be shaped to any surface curvature (e.g., concave or convex) by cutting away a part of the lens surface with a femtosecond laser 462, 466 (see
In another embodiment, the solution of collagen alone or with another polymer is mixed with a photosensitizer, such as riboflavin or Rose Bengal, and is poured in a 3-D printer, and heated to 37 degrees C. and irradiated with UV radiation of 3 mW/square for 1-2 minutes to create some scaffold collagen, then the 3-D printer unit is activated with appropriate software to print out in 3-D the synthetic collagen/polymer combinations to a desired shape and refractive power with an index or the refraction of 1.3, the lenslet is implanted in the corneal stroma after soaking it in the operating room, and creating a corneal pocket injected with riboflavin and hyaluronic acid for ease of the implantation, after which the cornea is UV radiated.
In one embodiment, the synthetic lenslet is placed in an injector having a needle and the lenslet combined with hyaluronic acid as a lubricant and riboflavin simultaneously are injected inside the prepared corneal pocket followed with UV radiation to crosslink the lenslet and the wall of the corneal pocket and prevent an immune response to the lenslet.
In one embodiment, the lenslet carries slow release polymeric nanoparticles which have medication(s) such as anti-inflammatory and antibacterial medications, etc.
Since the water content of the normal cornea is about 78-80% of the cornea and the collagen component is about 15-20%, the composite of the synthetic collagen hydrogel corneal lenslet can be made in the similar range of water concentration or less, e.g., 50% to 10% or less without changing the refractive index of the cornea by crosslinking it while increasing the density of the fibrils in the lenslet.
In one embodiment, the collagen used can be Type I, Type II, Type III, Type IV, Type V, Type VI, Type XI collagen, or a combination thereof, but preferably Collagen type I.
In one embodiment, the molded lenslet is removed from the mold by removing the part around the lenslet or immersing the mold in the phosphate buffered solution containing riboflavin that penetrated the lenslet and the lenslet and the wall of the corneal cavity are crosslinked subsequently with UV radiation that crosslinks the lenslet, the wall of the corneal cavity and eliminate potential infective germs by photodynamic therapy.
In one embodiment, the composition of the collagen hydrogel, e.g., type I collagen is generated by mixing collagen powder with a desired concentrations mixture with only one crosslinker, such as riboflavin in 0.1% to 2%, etc. that does not crosslink the collagen molecules without presence of the UV light including UVA and UVB or UVC; other non-photoactivated chemical crosslinker starting crosslinking immediately after their addition to the collagen hydrogel are not as well controlled as the photoactivated ones, wherein the composite is heated to 37 degrees C. to initiate a phase transition and some febrile mesh from in the gel, then the fluid is expressed out of the mixture mechanically to the desired thickness by compressing the collagen hydrogel in the container, then exposing the hydrogel lenslet plus crosslinked or photosensitizer with UV radiation or other wavelength of light depending on the photosensitizer to achieve a lenslet texture for its refined surface modification with an excimer laser or femtosecond laser and implantation in the cornea pocket that is crosslinked with riboflavin and UV radiation.
In one embodiment, for molding, the collagen and water plus riboflavin are mixed, then compressed to reach a thickness of about ½-⅓ of its original thickness or less and crosslinked with one crosslinker, such as riboflavin/UV laser light with a power of 15-30 mW/cm2. Since the surface of the lenslet defines the refractive correction needed not its index of the refraction, the lenslet is crosslinked, then shaped by modifying its already refractive surface with an excimer laser or cut with a femtosecond laser to the desired refractive power as needed to compensate for the patient's refractive errors, using a wavefront technology and Shack-Hartmann sensor prior to its implantation.
In one embodiment, the bottom surface of the mold where the collagen gel is formed defines if the lenslet will be a convex lenslet or concave lenslet or an astigmatic lenslet, etc.
In one embodiment, the photosensitizer can be xanthine, or any other photosensitizer that generates a photodynamic effect producing singlet oxygen and reactive species that initiate crosslinking of the proteins, such as collagen when exposed to a laser light that is absorbed by the photosensitizer.
In one embodiment, the density of the lenslet collagen hydrogel mesh is increased to prevent cell migration in the lenslet by removing >95% of its water content, then further cross-linking and its surface is shaped to create a lens let that is difficult to be invaded by inflammatory cells, etc. and the corneal pocket's wall is crosslinked after lenslet implantation to create an amorphous crosslinked lenslet with a crosslinked wall of the host corneal cavity which now will not induce an immune response in the host cornea or its erosion.
In one embodiment, the lenslets are combined with polymeric slow drug release nanoparticles such as polylactic, polyglycolic acid, or a mixture thereof or polycaprolactone, polyanhydrides, micelles etc. that can penetrate the lenslet and release medication after their implantation as described in U.S. Pat. No. 10,278,920 describing a corneal drug delivery system, which is hereby incorporated by reference as if set forth in its entirety herein.
In one embodiment, the concentration of the collagen gel, e.g., 1-15% and water of 50 to 70%/riboflavin mixture or 0.1%-2% and the temperature of the medium 37 degrees C. defines how slurry the mixture of collagen gel/fibrils is to pass through the nozzle of the 3-D printer to make a 3-D lenslet to the desired width of 2-14 mm and thickness of 0.1-1 mm, and curvature of its surface, convex or concave or astigmatic, and the mechanical stability of the lenslet is defined by the degree of its crosslinking with the UV radiation of 10 mW/cm2 to 30 mW/cm2 or more after the initial lenslet is formed by the 3-D printer.
In one embodiment of the 3-D printed lenslet, the polymeric slow release nanoparticles of polylactic or polyglycolic acid, etc. are added to the collagen gel before it is pressed out of the nozzle of the 3-D printer unit, to release the medication after implantation in the corneal pocket which is crosslinked simultaneously with a photosensitizer along with implantation of the lenslet, which is crosslinked with UV radiation.
In one embodiment of the molded lenslet, the mold container is made of two sections: (a) a hollow cylindrical upper portion and (b) a base portion with a curved smooth surface that combine to make a container where the surface of the base can be convex, concave, astigmatic, or flat. In the mold, collagen type I can be used, or collagen type I in combination with collagen type II or III, and/or recombinant collagen can be used. The percentage of the collagen in a physiological solution can be from 1% to 25%, and water to which riboflavin is added at desired 0.1%-2% concentrations are pored inside the mold container, the collagen swells in the water and expands without being dissolved, thus building a collagen mesh that is not crosslinked. One can add any medications desired in a non-toxic concentration to be released as slow release polymeric nanoparticles, to the solution at this stage, so as to prevent infection or inflammation, etc.
In one embodiment, by increasing the temperature of the mold and the collagen hydrogel/riboflavin solution to 37 degrees C., small fibrils are formed inside the mold. This mixture can be used in developing a lenslet by molding or using a 3-D printer by exposing the collagen mesh to low power UV radiation such as 1-3 mW/cm2 for 1-2 minutes, the fibrils are slightly more interconnected, but they are not resilient and can be manipulated to pass through either through the nozzle of the 3-D printer or they can be used for molding.
In one embodiment of the molded lenslet, the excessive water content of the mold can be removed by using a software controlled plunger 436 that fits inside the mold and pushes the gel 442 to a desired degree forcing the fluid in the collagen hydrogel to exit through the small side holes in the wall of the mold (see
In one embodiment of the 3-D printed lenslet, the mixture of hydrogel at 37 degrees C. and partially crosslinked hydrogel is compressed to the degree that it can pass through the 3-D printer's nozzle to form the lenslet under the control of the printer's software and build a lenslet this is convex, concave, astigmatic, or any combination thereof and to the desired shape. At this stage, the shape or refractive power of the molded lenslet or 3-D printed lenslet can be further modified with the use of a femtosecond laser or an excimer laser under the control of software using wavefront technology and a Shack-Hartmann system to create a lenslet surface to the desired convexity, concavity, or astigmatism to correct precisely the refractive power of the patient as needed.
In one embodiment, a corneal stromal cavity in the patient's corneal stroma is prepared to the desired size so that the lenslet can be implanted in it with ease or with the help of an injector and viscoelastic material, such as heparin through a small incision made to access the cavity in the peripheral cornea.
In one embodiment, a small amount (0.05 ml) of riboflavin or other photosensitizer is injected in the stromal cavity over the lenslet to penetrate the lenslet and the wall of the cavity.
In one embodiment, ultraviolet (UV) radiation is applied at desired power of 3-30 mW/cm2 or more and a desired time of 1-5 minutes through the corneal surface to further crosslink the lenslet and the wall of the stromal cavity preventing an immune response from the host.
In a further embodiment, one uses a human cornea or cornea from genetically modified animal, such as a pig or collagen obtained mainly from a cornea (type III collagen) or a mixture of various collagen types used as inlay for creation of a supporting tissue, or modification for refractive errors or as pinhole and crosslinked because, the crosslinked corneal tissue does not inhibit transport of the water and nutrients through it regardless where in the corneal stroma it is implanted, the water and nutrients pass from the back side of cornea through the inlay (implant) to the other side of the cornea or water etc. passes from the front to the back of the cornea. As a result, the crosslinked corneal inlay does not create tissue anoxia or foreign body immune response, etc. to lead to cellular immune stimulation that would cause rejection of the inlay as seen with previous polymeric, e.g., acrylic solid lenses, when implanted inside the cornea.
In one embodiment, the corneal inlay of 5-9 mm in diameter and a thickness of 10-300 microns is obtained from human eye bank eye, or genetically modified cornea of an animal, or 3D printed corneal collagen is tattooed at its center with a biocompatible non-toxic dark or black India ink or acrylic black ink, etc., the central tattooed area 502 of the inlay 500 encompasses an area of 1 mm-5 mm (see
In one embodiment, a corneal inlay is made from human eye bank eye, or genetically modified cornea of pig or another animal, or 3-D printed collagen or molded from collagen and other proteins, then the central 4-5 mm area of the inlay will be tattooed with a biocompatible non-toxic dark or black India ink or acrylic black ink, etc. a hole with a diameter of <2 mm (see
In one embodiment, as described the pinhole is created inside a corneal inlay with >5 mm in diameter then a central 4 mm tattooed area is cut with a trephine of femtosecond laser creating a hole 506 with a tattooed rim of <2 mm in diameter or more (see
In one embodiment, a virtual pinhole with the diameter of 3-4 mm is created by tattooing the peripheral 2 mm diameter of the corneal inlay 558, having a thickness of 10-30 micron creating a virtual pinhole 564 (see
In one embodiment, the pinhole with the diameter of 3-5 mm with a thickness of 10-20 micron using a femtosecond, the inlay is entirely tattooed with a biocompatible non-toxic dark or black India ink or acrylic black ink etc., then the inlay is crosslinked with riboflavin and or methylene blue combination and UV radiation, using a trephine or a femtosecond laser a central hole or 1-2 mm is cut in the tattooed inlay, the pinhole dark corneal inlay is implanted inside the central part of the host cornea using an injector and hyaluronic acid after creating a 5 mm in diameter pocket in the center of the host cornea to treat presbyopia eliminating the potential rejection of the pinhole inlay.
In one embodiment, the inlay 500 from human eye bank eye, or genetically modified cornea, or 3-D printed collagen or molded from collagen and other proteins with the central virtual or a regular hole 506 and darkened tattooed rim 502 is prepared for implantation in the human cornea using a LASIK flap 520 in the host cornea 518 (see
In one embodiment, the corneal inlay with a central hole or virtual hole is 3-D printed or molded as described above to which a darkened polymeric ring 512 (see
In one embodiment, the inlay with a dark central ring is used after a LASIK flap is formed in the host cornea and the flat inlay 500 is positioned over the corneal stroma and its surface can be modified with an excimer laser 522 ablating the entire inlay to correct the refractive error (see
In one embodiment, the inlay can be removed prior to a cataract extraction and the refractive error is corrected with an intraocular lens with or without a through central hole.
In one embodiment, with a corneal pocket procedure where a pocket 528 is formed in the cornea 526 of the eye using a femtosecond laser 530, the crosslinked corneal inlay 500 with the central hole 506 is implanted in the pocket 528 of the cornea 526, and crosslinked as above, then after a period of time if one desires, one can perform a Photo-Refractive keratectomy (PRK) (see
In one embodiment, the dark ring can be made from the eye bank cornea or genetically modified animal cornea tattooed with a biocompatible non-toxic dark or black India ink or acrylic black ink etc. or with PEGylated carbon nonospheres or nanotubes of 5-10 micron long that are mixed with polymeric nanoparticles such as PMMA, hydrogels, silicone, PVDF, polypropylene, polycarbonate, PVC, polysulfone, PEEK, polyethylene, acrylic copolymers, polystyrene, or collagen gel and crosslinked subsequently or its surface can be modified prior to implantation in the corneal stroma and combined with crosslinking the implant and the stromal tissue.
In one embodiment, for 3-D printing an organic corneal inlay and crosslinking it with riboflavin or another photosensitizer and UV radiation while the 3-D structure of the ring with carbon nanotubes or carbon nanoparticles, in acellular collagen or another polymer, absorb 99.99% of the incoming light preventing light from escaping, thus creating a very dark ring inside the inlay with a clear peripheral organic inlay.
In one embodiment, after 3-D printing or creating an inlay from human or animal cornea, a 1-2 mm wide dark cylinder 536 (see
In one embodiment, a collagenous dark ring can be made by tattooing the cornea with acrylic ink, carbon black or carbon nanoparticles or PEGylated carbon nanoparticles or PEGylated nanotubes of 5-10 micron long that are mixed with polymers such as PMMA, hydrogels, silicone, PVDF, polypropylene, polycarbonate, PVC, polysulfone, PEEK, polyethylene, acrylic copolymers, polystyrene, polyvinyl proline, polyvinyl fluorine or collagen gel and the ring placed over the host corneal stroma, having a LASIK flap before or after correcting the refractive error of the eye on the inlay's surface with an excimer laser and the inlay and the host tissue are crosslinked with the riboflavin and UV radiation to prevent rejection of the inlay.
In one embodiment, an injectable mixture of carbon nanotubes or nanoparticles made from carbon or other material and acrylic polymers etc. can be used for tattooing the corneal inlay at the inlay's central area so that a circular part of its center can be cut away with a trephine or a femtosecond laser, to create the central through and through hole in the inlay while leaving a dark rim around the hole and a clear peripheral donor cornea, that is modified with an excimer laser and crosslinked with riboflavin and UV radiation to be implanted inside a corneal pocket, which is then crosslinked with riboflavin and UV radiation.
In one embodiment, the central 1-2 mm of the transparent corneal inlay is left untouched while the tissue surrounding it is tattooed with an injectable carbon nanoparticles and an acrylic polymer to create a dark circular ring with a total width of 2-3 mm or more functioning as a virtual pinhole 560 (see
In one embodiment, a circular ring of a diameter of 1-2 mm or more can be tattooed through the surface of the cornea for a distance of 10-50 microns to create a pinhole in the cornea without implanting an inlay inside the cornea, thereby creating a semi-permanent pinhole for the eye with or without standard corneal crosslinking of human animals to provide them with an extended focal point for far and near.
In one embodiment, after the inlay implantation inside the corneal stroma the inlay and its surrounding tissue is crosslinked with riboflavin and UV radiation to prevent an immune response and rejection of the inlay.
In one embodiment, the central pinhole 546 and its dark surrounding rim 544 of tissue occupies the central 3.5 mm in diameter part of the inlay 542 (see
In one embodiment, the corneal inlay with a central hole and darkened peripheral hole is made by tattooing from human eye bank, or animal of genetically modified animal or not modified animal cornea or 3-D printer collagen or molded collagen with the diameter of 5 mm is cut with a trephine, or microkeratome, or femtosecond laser, the inlay is tattooed with the inlay is cut with a microkeratome or a femtosecond laser or an excimer laser to a thickness of 10 or more microns and in diameter and the inlay and the surrounding corneal tissue after implantation is crosslinked to prevent rejection.
In one embodiment, the corneal inlay is made from human eye bank eye or genetically modified animal cornea or animal corneal is made non-immunogenic with a combination of riboflavin and riboflavin solution and irradiated with a UV laser to crosslink the RNA, DNA, proteins, and glycoproteins inside the cornea to be modified subsequently with an excimer laser or femtosecond laser for implantation inside the cornea of human or an animal to correct their refractive error and crosslinked the wall of the corneal pocket to prevent their rejection by crosslinking the corneal cavity surrounding the inlay.
In another embodiment, the corneal inlay is made from the animal corneas such as dog, horse, pig or any other animals or an animal whose genes are modified first with recombinant genetic technology to prevent HLA histocompatibility response in human tissue, the inlay is initially de-cellularized with a solution of sodium dodecyl sulfate and or benzalkonium chloride, and/or treated with riboflavin and methylene blue photosensitizers and UV radiation to crosslink all cellular protein, glycoprotein and RNA and DNA of the cells and make the tissue non-antigenic while the inlay remains transparent but permits transport of water and other molecules through it, it is then processed for providing a central through hole and with or without tattooing the edges of the holes or implanting a thin polymeric darkened ring inside the inlay having the same thickness as the inlay and can be ablated with an excimer laser to modify the refractive error of the eye and after implantation and the central part of the inlay does not lift up selectively the central area of the cornea and finally the inlay and tissue surrounding the inlay are also crosslinked to kill the corneal cells and pathogens, creating an immune privileged space for the inlay implantation while correcting the refractive error for far and near and enhancing the mechanical stability of the host cornea.
In one embodiment, the animal cornea or human corneas is decellularized chemically e.g. sodium dodecyl and or undergoes a corneal crosslinking with 0.1% to 5% riboflavin and/or methylene blue at concentration of 4 mg/L or more and UV radiation at 320-380 nm wavelength and the power of 3-10 mw/cm2 to crosslink the acellular organic inlay with intercellular and cellular protein, glycoproteins and RNA or DNA, damaging all cells, bacteria, viruses, or parasites in the cornea, sterilizing the inlay maintaining the transparency of the inlay and simultaneously preventing an immune response to the inlay.
In one embodiment, the inlay is crosslinked, then is ablated with an excimer laser equipped with a wavefront technology to correct precisely the refractive power of the eye after the inlay is implanted inside the host cornea and crosslinked.
In one embodiment, the refractive power of the inlay is corrected prior to the corneal crosslinking, using an excimer laser and wavefront technology and Shack-Hartmann sensor to reshape the inlay and to correct refractive error of the patient after implantation, the inlay is crosslinked with riboflavin alone or in combination with methylene blue and irradiated with UV radiation killing the cells and potential bacteria, viruses or parasites in the corneal inlay then is implanted inside a corneal pocket created by a femtosecond laser in the host cornea, then Riboflavin is injected in the corneal pocket over the inlay and the surrounding corneal inlay is crosslinked with UV radiation from the outside the cornea to prevent an immune response from the host cornea.
In one embodiment, the procedure is as LASIK procedure, thus creating a corneal flap with a microkeratome or an excimer laser.
In another embodiment, the corneal inlay with the central hole and dark wall is implanted in a corneal pocket of human or animals such as horse dog, etc. which is created by a femtosecond laser application inside the corneal stroma at desired level inside the stroma.
In one embodiment, prior to the implantation of the corneal inlay a central hole is created in the inlay then the circular polymeric dark ring is place inside the inlay's producing through and through central hole so that the ring and the inlay have the same thickness and after their implantation the corneal flap is not elevated forward and increases the mechanical stability of the cornea in high myopia and or in keratoconus.
In one embodiment, the wall of the hole in the inlay is tattooed for a diameter of 0.5-2 mm or more as needed, the dark tattoo can be applied uniformly to either surface of the inlay with a dark none toxic particles such as carbon, the tattooing can be done before cutting out the central part of the inlay with a trephine or a femtosecond laser, leaving a the dark rim of tattooed tissue.
In the femtosecond pocket procedure, the refractive power of the eye is corrected on the inlay with the central hole prior to its implantation and the inlay and the corneal wall surrounding it is crosslinked by injection of riboflavin solution inside the corneal pocket and the eye is irradiated with UV laser light from the outside, to crosslink the inlay and the corneal tissue preventing rejection of the inlay while correcting for presbyopia and other refractive errors of the eye.
In one embodiment, in the LASIK flap procedure, the inlay with its central opening is placed over the corneal stromal after creating a corneal flap and the inlay's refractive power is corrected with an excimer laser by ablating the inlay's surface, and crosslinking it, strengthening the biomechanical stability of the cornea with the inlay in high myopia or eyes with keratoconus.
In one embodiment, in a corneal flap procedure, after correction of the refractive power of the eye on the inlay, it is crosslinked by placing a few drops of a solution of a photosensitizer, such as riboflavin, with or without methylene blue over the cornea and the corneal flap is repositioned over it, the cornea is crosslinked with UV radiation done from outside the eye, crosslinking the inlay and the surrounding stromal tissue of the flap and the corneal stroma to prevent rejection of the inlay.
In one embodiment, after making a corneal pocket with a femtosecond laser, the excimer laser ablated corneal inlay with its central ring or darkened tissue around the central opening, is implanted inside the pocket so that the central hole coincides with optical axis of the eye then a few drops of riboflavin at 0.1-1% solution alone or in combination with methylene blue at <2 mg/L concentration are injected over the inlay to penetrate it and the surrounding corneal tissue, then the eye is irradiated with UV radiation to kill all cells in the inlay or surrounding cornea along with potential bacteria, viruses or parasites while crosslinking the host corneal tissue around the corneal pocket.
In both LASIK or corneal pocket procedure, an antibiotic or an anti-inflammatory agent is applied to the cornea or injected in the corneal pocket to protect the cornea from infection, or deliver the medications by using slow release polylactic or glycolic or combination of them or other slow release compound and release them for 4-6 weeks.
In one embodiment, an inlay with a desired thickness of 20 micron to 500 micron or more and a diameter of 6-9 mm is obtained from the human eye bank or genetically modified animal or not modified, such as pig or molded or 3D printed from collagen, etc. and crosslinked to make them non-immunogenic for transplantation.
In one embodiment, the corneal inlay made of human or genetically modified animal cornea, crosslinked and its surface is modified as described, one can implant it in almost any depth from the surface of the host cornea and does not need to be implanted at a depth beyond 120-200 microns from the surface, which cannot transmit the change of the inlay surface to the corneal surface precisely which is important in refractive surgery this is followed with crosslinking the tissue around the inlay as described above.
In one embodiment, all refractive surgeries in human or animals can be done on the corneal inlay with central hole can be repeated again by replacing the old inlay with a new corneal inlay with a central hole to treat refractive errors of the eye and presbyopia simultaneously or perform a bilateral procedure permitting the patient to see stereoscopically the objects located at different focal points in front the eye and regardless of its original eye's dioptric power or age of the patient for correction of myopia, hyperopia, stigmatism, and presbyopia since no tissue is removed from the cornea, without the risk of rejection of the crosslinked inlay surrounded by crosslinked host corneal tissue and without causing corneal haze.
In one embodiment, the inlay is used to correct hyperopia by increasing the convexity of the central part of the cornea. In this embodiment, the implant is a small decellularized corneal inlay with the diameter of 2-4 mm and a thickness of 10 to 40 microns with a central hole of 1-2 mm and a tattooed 1-2 mm peripheral rim that can be implanted in a cavity of 5 mm in diameter made in the cornea with a femtosecond laser to achieve a precise dioptric power in the center of the retina which create addition convex curvature in the center with a pinhole effect with or without crosslinking the inlay and the corneal tissue achieving simultaneously a bifocal near and far vision for the patient or animal. The inlay and the surrounding tissue is crosslinked with a solution of riboflavin with or without methylene blue and UV laser radiation to prevent rejection of the inlay and simultaneous crosslinking of the adjacent corneal tissue.
In one embodiment, the genetically modified cornea can be used for full thickness corneal transplantation while crosslinking one-half or more of the thickness of the cornea with riboflavin and UV radiation.
In one embodiment, the ablatable corneal inlay for simultaneously correcting refractive errors and presbyopia is provided with a virtual hole or actual hole surrounded by a clear transparent fluid which is a permeable organic or non-organic composition, etc.
In one embodiment, using a method of corneal inlay implantation where the inlay can be made either from collagen, molded, or 3-D printed to the desired shape or it is made from corneal stromal tissue harvested from human eye bank eyes, from deceased patients, or from animals, such as pigs, etc., with genetic modification or the animal eyes are obtained from the slaughter house, then prepared so that their nucleus and proteins, etc. lose their immunogenicity using high concentration of methylene blue >4 microgram/ml combined with peptide nucleic acid and/or PARP inhibitors to block the cells RNA and mRNA of the corneal cells or pathogens, in a solution with high osmolality of more than 300 mOS, that both damages the nucleic acid and withdraws fluid from the cornea or combined with riboflavin, irradiated with UV radiation or a wavelength that is absorbed by methylene blue (MB) at 660 nm to crosslink the antigenic proteins, glycoproteins of the corneal inlay, reduce or eliminate their antigenicity prior to implantation or during the implantation in the cornea after radiation with UV or another wavelength, etc.
In one embodiment the human or animal corneas are separated from the sclera, conjunctiva, or retina, etc., stored in a solution, such as preservatives, to kill and eliminate the cellular elements or pathogens as described in U.S. Pat. No. 10,881,503 to Peyman using Benzalkonium chloride (BAC) solution or with 0.1% sodium dodecyl sulfate (SDS) or combination, etc. and washed in a physiological solution with slightly higher osmolarity to reduce toxicity of SDS, followed by washing, etc. U.S. Pat. No. 10,881,503 to Peyman is incorporated by reference herein in its entirety.
In one embodiment, the de-cellularized corneas are cut either with a microkeratome or a femtosecond laser, etc., and kept moist with Benzalkonium chloride in hyaluronic acid or low molecular weight heparin or albumin so that the tissue does not swell.
In one embodiment, uniform corneal stromal inlays are prepared with the thickness of 40 microns to 400 microns with a diameter of 3-9 mm, preferably a diameter of 5-8 mm or more, with a 30-150 micron thickness or more, and the inlays can be exposed to UV or cobalt radiation, etc. if needed to eliminate bacteria, fungi, or viruses or parasites, or exposed to high concentration of methylene blue >3 microgram/ml with or without β-propiolactone (BPL) or a mixture of methylene blue (MB) at a concentration of >4 microgram/ml for a period of time 1-5 hours or more to damage RNA and DNA of the inlay or any organism, or crosslinked with riboflavin and UV radiation wavelength of about 370, or wavelength of about 650 nm for MB crosslinking of the inlay, etc., and to damage potential organisms, viruses, bacteria, fungi or parasites in the inlay, or crosslinking can be performed after implantation in the corneal stroma.
In one embodiment, one predetermines the refractive error of the patients with various means such as phoropter, wavefront guided excimer laser technology, or an automated objective phoropter (see e.g., U.S. Pat. No. 8,409,278, which is incorporated by reference herein in its entirety) that provides a correction to the refractive error of the eye in less than 5 seconds, the prescription is printed out by the unit prior to corrections of refractive errors with the refractive error being corrected with wavefront guided excimer laser prior to its implantation.
In one embodiment, a standard LASIK flap is produced either by a microkeratome or a femtosecond laser, etc. (see
A de-cellularized and sterile corneal inlay is selected with the size and/or thickness depending on the need of the eye to create emmetropia correcting both spherical and cylindrical errors, etc. as needed for the patient.
In one embodiment, the corneal inlay is positioned on the exposed corneal stroma, under a prepared LASIK flap. Initially, the inlay is treated with an excimer laser and/or femtosecond laser to provide a uniform size and thickness of the corneal inlay, e.g., 8-9 mm or more in diameter and 30 microns or more in thickness, e.g., for correcting a −5.00 diopter error, the inlay is ablated in its center on an area of 4-6 mm with an excimer laser, calculated based on a mathematical formula and laser software where removal of each 10 microns of the circular inlay's surface creates one dioptric power change. In the present procedure, the surgeon divides the 5.00 dioptric ablation between the corneal inlay and the patient's stroma. The correction of the inlay for −3.00 dioptric power or 30 micron ablation is done on the center of the donor inlay and the remaining −2.00 D power is done on the patient's stroma (total amount of tissue removed is 50 microns, which equals −5.00 D power—refer to
In one embodiment, the ratio of ablation of the inlay versus the corneal stroma can be any ratio, e.g., creating 50%/50% more or less ablation producing potentially >15.00 dioptric power correction. However, it is more desirable to ablate more on the donor corneal inlay than the corneal stroma etc. depending on the dioptric power needed to fully correct refractive error of the eye.
This method of dividing the amount of corneal ablation between the inlay and the host corneal stroma creates a hole in the inlay by the initial ablation, through which the patient's cornea is exposed, which is then ablated for 20 microns or about −2.00 dioptric or more for additional correction. Then, when the transparent corneal flap is repositioned over the inlay, a part of the flap comes directly in contact with the transparent patient's stroma underneath it or through the doughnut hole of the inlay. The patient's eye corrected with this technology (e.g., which may be called a Tissue-Augmented (TA) LASIK procedure) can immediately see the outside world clearly, since there is no tissue in the center of the doughnut-shaped inlay.
In one embodiment, this procedure can be repeated, or the ablation can be modified or the new inlay can be placed over the old one or the old inlay can be removed and a new one inserted in its place with ease in the cornea of a patient's eye that is growing, etc.
In one embodiment, the advantage of Tissue-Augmented LASIK Surgery (TALS or TA LASIK) over the ablation of the inlay only, is that the central opening (doughnut) created after the excimer laser surgery in the donor corneal inlay always remains clear, even if the remaining peripheral inlay tissue is initially less transparent (because of the absorption of water or other medication during the inlay preparation, rendering the inlay tissue slightly less transparent). However, in 1-2 weeks, the inlay becomes as fully transparent as the rest of the cornea. Ultimately, the central ablated hole in the inlay (doughnut) provides the patient with a clear window immediately after the TA LASIK procedure, through which the outside world can be seen or the patient can read clearly immediately after surgery as is the case after LASIK surgery which is not tissue augmented and is limited to 7.00 D power.
In one embodiment, after corneal implantation and ablation, one applies two or more drops of about 1% or more riboflavin solution or another photosensitizer for crosslinking with or without Rock inhibitors with or without allopregnanolone at <8 nanograms/ml to encourage nerve growth, over the inlay which is then covered immediately with the corneal flap, permitting for 1-5 minutes, the Riboflavin to penetrate the inlay and the surrounding stroma which are then crosslinked with UV radiation of 3-10 milliW/cm2 or more from the outside of the eye through the cornea for 1-10 minutes or more to crosslink the inlay and its surrounding tissue and kill all pathogens by UV and crosslink the inlay and sterilize the corneal cavity and increase the mechanical stability of the cornea after its crosslinking (see
In one embodiment, in the postoperative period, the cornea is treated with a solution or ointment of medications such as a Rock inhibitor, Wnt inhibitors, GSK inhibitors, or anti-integrin alone or with steroids or NSAIDs or a nerve growth factor to encourage nerve growth in the previously cut corneal tissue and reduce inflammation. Since the corneal flap is mostly not crosslinked because the photosensitizer will be limited to the inlay and surrounding tissue, the growth of the corneal nerve recovery in the corneal flap that is not crosslinked is enhanced, using the above-mentioned mediations or with addition of a steroid, NSAIDs or an antibiotic or antiviral, etc. after surgery. This can also enhance recovery and the wound healing of the corneal nerves and return of the corneal sensation, thereby preventing dry eye after surgery.
In one embodiment, in the postoperative period, the cornea is treated with a solution or ointment of medications such as Rock inhibitors, Wnt inhibitors, GSK inhibitors, or anti-integrin alone or with steroids or anti-inflammatory agents, with or without complement pathway inhibitors, such as C3 inhibitors—AMY-101 (NCT04395456) and APL-9 (NCT04402060); C5 inhibitors—eculizumab (NCT04346797 and NCT04355494), Cl esterase inhibitors, which block the classical complement pathway with anti-IL6 medication, such as Kevzara, tocilizumab, rituximab, etc. and antibiotics, such as tetracycline derivatives, a metalloproteinase inhibitor and/or low molecular weight heparin (Lovenox), and/or in a suitable medium to enhance nerve growth after refractive surgery.
In one embodiment, after refractive surgery, the cornea is treated with a solution or polymeric nanoparticles PGLA and a Rock inhibitor, alone or with steroids or with a complement inhibitor, such as anti-IL6 medication Kevzara, in a medium of low molecular weight heparin (Lovenox) with or without an antibiotic.
In one embodiment, a Rock inhibitor or another cell inflammatory pathway inhibitor in a semifluorinated alkane combined with a complement inhibitor, such as Kevzara, and or an anti-VEGF, such as bevacizumab and/or low molecular weight heparin (LMWH), such as Lovenox etc., is administered intravitreal or topically to the cornea to enhance nerve growth and prevent cell loss caused by chronic inflammation or in an aging eye.
In one embodiment, the corneal inlay or an inlay with the shape of doughnut can be treated or crosslinked ex-vivo and the refractive error of the patient's eye is corrected on the inlay with or without a 1-3 mm central hole prior to implantation, the inner wall of the doughnut hole is darkened with a dye and it is implanted in a corneal pocket, such as a pocket made with a femtosecond laser in the corneal stroma and a small incision is made to implant the doughnut inlay in the corneal pocket (see
In the embodiment of
In one embodiment, one uses a femtosecond laser to create a central corneal cavity in a cornea with keratoconus from 7-10 mm in diameter, the corneal tissue is separated with a spatula, then a corneal inlay is created with a diameter of 7-9 mm and a central hole of 1-3 mm and a thickness as needed to ablate the cornea. The inner wall of the central hole is darkened with a dye or carbon nanoparticles etc., leaving a peripheral area clear, thereby creating an inlay that can compensate for most to all of the refractive error of the cornea, and presbyopia then the inlay with the central hole (doughnut) is crosslinked with riboflavin and UV radiation prior to its implantation or after implantation. The inlay is covered with hyaluronic acid or a viscoelastic material and injected inside the corneal cavity. Other medications, such as inflammatory pathway inhibitors with or without steroids or antibiotics, are injected either inside the corneal cavity or applied postoperatively to prevent an infection, reduce inflammation and enhance the nerve regeneration.
In one embodiment, this technology with or without modification can be employed to treat refractive error and presbyopia.
In one embodiment, the use of animal inlays, decellularization and riboflavin crosslinking of the inlay eliminate the antigenic proteins in the inlay regardless of the origin of the inlay and makes them less immunogenic in the host tissue. The composition of the inlay should have <30%-50% water content to prevent swelling of the inlay. The eye should be treated with a combination of a Rock inhibitor, steroids or adalimumab, etc. to suppress an immune response.
In one embodiment, the TA LASIK can be done with a femtosecond laser to remove the desired tissue from the inlay and the host cornea, the central part is removed carefully so as to leave the remaining inlay tissue and a central hole in the inlay, followed by crosslinking the inlay and the wall of the stromal tissue before or after the flap is replaced over the inlay.
In one embodiment, the riboflavin crosslinking can be repeated as needed to denature the corneal tissue around the inlay.
In one embodiment, the cell inflammatory pathway inhibitors can be combined with anti-inflammatory agents such as doxycycline, or biologics such as adalimumab, anti-VEGFs, antibiotics or complement inhibitors etc. applied to the cornea or conjunctiva after the surgery to suppress inflammation, while encouraging nerve growth in the tissue and prevent an infection.
Any of the features, attributes, or steps of the above described embodiments and variations can be used in combination with any of the other features, attributes, and steps of the above described embodiments and variations as desired.
Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is apparent that this invention can be embodied in many different forms and that many other modifications and variations are possible without departing from the spirit and scope of this invention.
Moreover, while exemplary embodiments have been described herein, one of ordinary skill in the art will readily appreciate that the exemplary embodiments set forth above are merely illustrative in nature and should not be construed as to limit the claims in any manner. Rather, the scope of the invention is defined only by the appended claims and their equivalents, and not, by the preceding description.
This patent application claims priority to U.S. Provisional Patent Application No. 63/348,092, entitled “Tissue-Augmented Corneal Inlay Surgery Technique”, filed on Jun. 2, 2022, and is a continuation-in-part of application Ser. No. 17/683,344, entitled “Ablatable Corneal Inlay For Correction Of Refractive Errors And/Or Presbyopia”, filed on Feb. 28, 2022, and Ser. No. 17/683,344 is a continuation-in-part of application Ser. No. 16/927,882, entitled “Molding or 3-D Printing of a Synthetic Refractive Corneal Lenslet”, filed Jul. 13, 2020, now U.S. Pat. No. 11,259,914, which claims priority to U.S. Provisional Patent Application No. 63/026,033, entitled “Molding or 3-D Printing of a Synthetic Refractive Corneal Lenslet”, filed on May 16, 2020, and Ser. No. 16/927,882 is a continuation-in-part of application Ser. No. 15/422,914, entitled “Intracorneal Lens Implantation With A Cross-Linked Cornea”, filed on Feb. 2, 2017, now U.S. Pat. No. 10,709,546, which claims priority to U.S. Provisional Patent Application No. 62/290,089, entitled “Method of Altering the Refractive Properties of the Eye”, filed on Feb. 2, 2016, and Ser. No. 15/422,914 is a continuation-in-part of application Ser. No. 15/230,445, entitled “Corneal Lenslet Implantation With A Cross-Linked Cornea”, filed Aug. 7, 2016, now U.S. Pat. No. 9,937,033, which claims priority to U.S. Provisional Patent Application No. 62/360,281, entitled “Method of Altering the Refractive Properties of an Eye”, filed on Jul. 8, 2016, and Ser. No. 15/230,445 is a continuation-in-part of application Ser. No. 14/709,801, entitled “Corneal Transplantation With A Cross-Linked Cornea”, filed May 12, 2015, now U.S. Pat. No. 9,427,355, which claims priority to U.S. Provisional Patent Application No. 61/991,785, entitled “Corneal Transplantation With A Cross-Linked Cornea”, filed on May 12, 2014, and to U.S. Provisional Patent Application No. 62/065,714, entitled “Corneal Transplantation With A Cross-Linked Cornea”, filed on Oct. 19, 2014, the disclosure of each of which is hereby incorporated by reference as if set forth in their entirety herein.
| Number | Date | Country | |
|---|---|---|---|
| 63348092 | Jun 2022 | US | |
| 63026033 | May 2020 | US | |
| 62290089 | Feb 2016 | US | |
| 62360281 | Jul 2016 | US | |
| 61991785 | May 2014 | US | |
| 62065714 | Oct 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17683344 | Feb 2022 | US |
| Child | 18205320 | US | |
| Parent | 16927882 | Jul 2020 | US |
| Child | 17683344 | US | |
| Parent | 15422914 | Feb 2017 | US |
| Child | 16927882 | US | |
| Parent | 15230445 | Aug 2016 | US |
| Child | 15422914 | US | |
| Parent | 14709801 | May 2015 | US |
| Child | 15230445 | US |
