UNIVERSAL IMPLANT PREFORM TO MODIFY THE CORNEAL CURVATURE AND THE METHODS TO MODIFY THE CORNEAL CURVATURE WITHTHE SAMEBACKGROUND OF THE INVENTION The present invention relates to a universal preform that is used to modify the curvature of a living cornea when implanted therein. The preform is made of synthetic or organic material and receives the shape of the appropriate configuration while receiving support on an exposed internal surface of the cornea. Description of Related Art: A normal emetropic eye comprising a cornea, lens and retina. The cornea and the lens of a normal eye that together adjust the light that enters the eye from a distant point, that is, infinite, to the retina. However, an eye can have a disorder known as ametropia, which is the inability of the lens and the cornea to correctly adjust the distant spot on the retina. The common types of ametropia are myopia, hyperopia or hyperopia and stigmatism. A myopic eye has either an axial length that is longer than that of a normal emetropic eye or a cornea or lens that has a greater refractive power than that of the cornea and lens of an emetropic eye. This greater refractive power causes the distant point to be projected in front of the retina. On the contrary, a hypermetropic or hyperopic eye has a shorter length than that of a normal emetropic eye, or a crystalline or cornea that has a lower refractive power than that of a lens or cornea of an emetropic eye. This lower refractive power causes the distant point to fit in the back of the retina. An eye that suffers from astigmatism has a defect in the lens or the shape of the cornea. Therefore, an astigmatic eye can not accurately adjust the images of the retina. A common method for correcting myopia is to place a "minus" or concave lens on the front of the eye to reduce the refractive power of the cornea and lens. Similarly, hypermetropic or hyperopic conditions can be corrected to a certain degree by placing a "plus" or convex lens at the front of the eye to increase the refractive power of the cornea and the lens. To correct astigmatism lenses with other shapes can be used. Concave, convex or other lenses are typically configured in the form of eyeglasses or contact lenses. This technique, which involves the placement of lenses in the front of the eye, is known as a keratectomy.
Although photorefractive keratectomy can be used to correct vision in eyes that have little myopia up to 6 diopters, or in eyes that suffer from hypermetropic, hyperopic or astigmatic conditions that are not very serious, this method is not effective in correcting eyesight who suffer from severe forms of ametropia. For example, photorefractive keratectomy is not effective in correcting myopia to a high degree of 6 diopters or greater, nor is it effective in correcting severe astigmatism or severe forms of hyperopia or hyperopia. For example, there are surgical techniques to correct to a certain degree these severe forms of ametropia. For example, in a technique known as keratomileusis, a microkeratome is used to remove a portion of the front of the living cornea from the main section of the cornea itself. The cut portion of the cornea is frozen and placed in a cryolathe (cryogenic frame) where it is cut and reshaped. Altering the shape of the cut portion of the cornea changes the refractive power of this cut portion, which thereby affects the location where the light entering the cut portion of the cornea is adjusted. The cut portion of the cornea with a new shape is reattached to the main portion of the living cornea. Therefore, the goal is for the cornea with a new shape to change the position where the light entering the eye fits through the cut portion., so that there is possibility that the light fits in the retina, thus remedying the atrophic condition. It is known that the technique of myopic keratomileusis is effective to cure myopic conditions within a range of 6 to 18 diopters. However, the technique is not practical because it uses very complicated and time-consuming freezing, cutting and thawing processes. In addition, the technique is not effective in correcting myopia conditions greater than 18 diopters. Keratophakia is another known surgical technique for correcting severe atrophic conditions of the eye by altering the shape of the cornea of the eye. In this technique, an organic or synthetic lens is implanted within the cornea so that by means of it the shape of the cornea is altered and thus its refractive power is changed. Consequently, it is convenient that, just as with the myopic keratomileusis technique, the shape of the cornea is altered to a degree that allows the entrance of light to the eye to fit correctly in the retina. However, the keratofacial technique is impractical, complicated and expensive since it requires the manufacture or cutting of a special lens before its insertion into the cornea. Therefore, a surgeon is required to maintain an assortment of lenses with many different shapes, or alternatively, to have access to expensive equipment, such as a "cryolathe" (cryogenic frame), which can be used to cut the lens prior to insertion into the lens. the cornea. Surgical techniques are also known that include the use of lasers of ultraviolet rays and with shorter wavelength to modify the shape of the cornea. For example, excimer lasers, such as those described in U.S. Patent No. 4,840,175 to Peyman, which emit pulsed ultraviolet radiation, which can be used to decompose or photosexture tissue in the living cornea to reshape the comea Specifically, the inventor hereby previously developed a laser surgical technique, known as on-site laser keratomycosis (LASIK). In this technique, a portion of the front part of a living cornea can be cut into the shape of a fin with a thickness of about 160 microns. This cut portion is removed from the living cornea to expose an inner surface of the cornea. Then a laser beam is directed to the exposed inner surface to remove a convenient amount of the inner surface up to 150-180 microns deep. The cut portion is then attached again to the excised portion of the cornea, and takes the shape of the excised portion.
However, because only a certain amount of cornea can be excised without the rest of the cornea losing stability or experiencing a lack of convexity (eclasia), this technique is not especially effective in correcting myopia to a high degree. That is, a typical living cornea has a thickness of approximately 500 microns average. The technique of laser excision requires that at least approximately 200 microns of stroma of the cornea remain after the excision is completed so that instability and lack of convexity do not occur. Hence, this procedure is not effective to correct excess myopia greater than 15 diopters since to reshape the cornea to the degree necessary to alter its refractive power, so that the adjustment of the eye is corrected enough, it would have to remove too much cornea. Examples of known techniques for modifying corneal curvature are discussed, such as those already mentioned in U.S. Patent No. 4,994,058 to Raven et al., U.S. Patent No. 4,718,418 to L 'Esperance, U.S. Pat. 5,336,261 for Barrett et al., U.S. Patent No. 4,840,175 for Peyman and a publication by Dr. José I. Barraquer, entitled "Keratomileusis and Keratophakia in the Surgical Correction of Aphakia" (Queratomileusis and Keratofachia in Surgical Correction). of the Afaquia).
Therefore there is a continuing need to improve methods that correct very severe ametropic conditions. SUMMARY OF THE INVENTION "Accordingly, a primary objective of the present invention is to provide an apparatus that can be used to modify the curvature of the cornea without experiencing the drawbacks associated with the known techniques discussed above, thereby correcting the atrophic conditions. Another objective of the invention is to configure the device to be placed on the surface of the cornea and to receive a new shape while it is on the surface of the cornea so that the device does not need to be manufactured in advance. or - modifying before its placement on the cornea - Another objective of the invention is to provide a method for modifying the shape of a cornea using a device that can be placed on the surface of the living cornea and that receives a new shape on the cornea. Another objective of the invention is to provide a method that modifies the form of a living cornea by removing a layer of the living cornea to expose a lower surface, placing a device on the exposed surface that can receive a new shape while "being on the exposed surface, giving new shape to the device and replacing the layer on the excess portion of the device with new shape so that it shapes the layer and thus the entire cornea. The above objectives are basically obtained by providing a universal-sized preform made of organic material, synthetic material or a combination of organic and synthetic materials, which can be placed on an exposed inner surface of a living cornea and which is excised with a laser beam for alter it to a particular form. The preform with universal size can be porous to allow oxygen and nutrients to pass through it. In addition, the preform can be made from living cells such as a donor cornea of a human eye (e.g., an eye bank) or a cultured cornea. A fin-shaped portion of the living cornea is removed to expose the inner surface of the cornea. The preform is placed on the exposed inner surface of the cornea and a laser beam is directed towards certain portions of the preform to remove those portions and thereby reshape the preform based on the type of ametropic condition (i.e., myopia) , hyperopia or astigmatism) of the eye that needs correction. The fin-shaped portion of the cornea is repositioned on the remaining portion of the preform, so that the remaining portion of the preform gives shape to the fin-shaped portion of the cornea that was joined again, thereby modifying the curvature of the cornea surface. Therefore, the universal preform can be used to correct serious ametropic conditions, such as excessive myopia up to 35 diopters. Other objects, advantages and remarkable features of the present invention will be seen in the following detailed description, which, together with the accompanying drawings, disclose preferred embodiments of the invention. Brief Description of the Illustrations With reference to the illustrations that are part of the original disclosure: Fig. 1 is a vertical sectional side view taken through the center of an eye showing the cornea, pupil and lens; Fig. 2 is a perspective view of an embodiment of a universal preform in accordance with the present invention; Fig. 3 is a front-ertical view of the embodiment shown in Fig. 2; Fig. 4 is a vertical top view of the embodiment shown in Fig. 2; FIG. 5 is a vertical sectional side view taken through the center of an eye showing the formation of a fin-like structure at the front of the cornea; Fig. 6 is a vertical front view of the cornea and the fin-like structure as taken along the lines VI-VI in Fig. 5; Fig. 7 is a vertical sectional side view taken through the center of an eye and showing the fin-shaped section positioned to expose an inner surface of the cornea; Fig. 8 is an enlarged vertical side view in section taken through the center of an eye showing the placement of the embodiment of the universal preform shown in the Figure. 2 on the exposed surface of the cornea; Fig. 9 is an enlarged vertical side view in section taken through the center of an eye and illustrating the universal preform shown in the Figure. 2 placed on the exposed surface of the cornea; Fig. 10 is a vertical front view of the cornea with the universal preform present on the exposed surface thereof as it was taken along the X-X lines of the Figure. 9; FIG. 11 is an enlarged vertical side view in section taken through the center of an eye showing the cornea and irradiation of a laser beam on the universal preform positioned on the exposed surface of the cornea; Fig. 12 illustrates the removal of the center of the universal preform by means of the laser beam; Fig. 13 is a vertical front reduced view of the excised universal preform taken along lines XIII-XIII in Fig. 12; Fig. 14 is an enlarged cross-sectional view of the preform and the cornea as taken along lines XIV ^ IV of Fig. 13; Fig. 15 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion placed back on the exposed surface of the cornea and the rest of the portion of the universal preform removed. showing Fig. 14; - Fig. 16 is a vertical side view in section taken through the center of the eye illustrating the excision of the universal preform as well as a portion of the cornea below the preform by the laser beam; Fig. 17 is a vertical sectional side view taken through the center of the eye illustrating the fin-shaped portion again positioned over the remaining portion of the preform and the excised portion of the cornea; Fig. 18 is a vertical sectional side view taken through the center of the eye showing the cornea and irradiation - of a laser beam on the peripheral portions of the universal preform that is placed on the exposed surface of the cornea; Fig. 19 is a vertical sectional side view taken through the center of the eye showing the removal of the portions of the universal preform by irradiation of the laser beam as shown in Fig. 18; Fig. 20 is a vertical front reduced view taken along lines XX-XX of Fig. 19; Fig. 21 is a transverse elongated view taken along lines XXI -XXI of Fig. 20; Fig. 22 is a vertical sectional side view taken through the center of the eye showing the cornea and fin-shaped portion reattached to the exposed surface of the cornea and the remaining portion of the universal preform excised by the cornea. laser beam as shown in Fig. 19; Fig. 23 is a vertical sectional side view taken through the center of the eye showing the removal of the portions of the universal preform and the exposed surface of the cornea below the preform by irradiation of a laser beam; FIG. 24 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform as removed. by the laser beam as shown in Fig. 23; FIG. 25 is a vertical sectional side view taken through the center of the eye showing the removal of the multiple portions of the universal preform by irradiation of a laser beam; Fig. 26 is a vertical front view of the excised universal preform taken along lines XXVI -XXVI of Fig. 25; Fig. 27 is a vertical sectional side view taken through the center of the eye showing the cornea and fin-shaped portion reattached to the exposed surface of the cornea and the remaining portion of the universal preform excised by the cornea. laser beam as shown in Fig. 25; Fig. 28 is a vertical sectional side view taken through the center of the eye showing the removal of the multiple portions of the universal preform and the cornea by irradiation of a laser beam; Fig. 29 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform as removed. by the laser beam as shown in Fig. 28;Fig. 30 is a vertical sectional side view taken through the center of the eye showing the removal of the universal preform asymmetrically by irradiation of a laser beam; Fig. 31 is a vertical front reduced view of the excised universal preform taken along the lines XXXI -XXXI of Fig. 30; Fig. 32 is a vertical sectional side view taken through the center of the eye showing the cornea and fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform as removed. by the laser beam as shown in Fig. 30; Fig. 33 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion attached again on the "exposed surface of the cornea and the remaining portion of the universal preform after a peripheral portion of the universal preform and a portion of the exposed surface were excised by a laser beam, Fig. 34 is a vertical sectional side view taken through the center of the eye showing a central portion of the exposed surface of the cornea that is excised by a laser beam, Fig. 35 is a vertical front reduced view of the exposed surface removed from the cornea taken along lines XXXV-XXXV of Fig. 34, Fig. 36 is a view lateral vertical section taken through the center of the eye illustrating the universal preform shown in the position of Fig. 2 on the exposed surface of the cornea and the removal of a central portion of the universal preform by a laser beam; FIG. 37 is a vertical sectional side view taken through the center of the eye showing the cornea and fin-shaped portion attached back to the exposed surface of the cornea and the remaining portion of the universal preform as removed. by the laser beam as shown in Fig. 36; Fig. 38 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion attached back to the exposed surface of the cornea and the remaining portion of the universal preform after which a central portion of the universal preform and a central portion of the exposed surface excised from the cornea were excised by a laser beam; Fig. 39 is a vertical sectional side view taken through the center of the eye showing the excision of the peripheral portions of the universal preform that is placed on the exposed surface of the cornea; Fig. 40 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion attached back to the exposed surface of the cornea and the remainder of the portion of the universal preform as they were removed by the laser beam as shown in Fig. 39; Fig. 41 is a vertical sectional side view taken through the center of the eye showing the cornea and fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform after which the periphery of the universal preform and a portion of the excised surface removed from the cornea surrounding the remaining portion of the preform were excised by a laser beam; Fig. 42 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached on the exposed surface of the cornea and a remaining portion of the universal preform that was removed asymmetrically by a laser beam; Fig. 43 is a vertical sectional side view taken through the center of the eye showing the cornea and fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform after which a portion of the excised exposed surface and the universal preform were excised by a laser beam asymmetrically; Fig. 44 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached to the exposed surface of the cornea and the remaining portion of the universal preform from where it is placed. removed multiple portions by means of a laser beam; Fig. 45 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform after which multiple portions of the excised portion of the exposed surface and multiple portions of the universal preform were excised by means of a laser beam; Fig. 46 is a perspective view of another embodiment of a universal preform in accordance with the present invention; Fig. 47 is a front view of the embodiment shown in Fig. 46; Fig. 48 is a bottom-up view of the embodiment shown in Fig. 46 as taken along lines XLVIII-XLVIII of Fig. 47; Fig. 49 is a vertical sectional side view taken through the center of the eye showing the removal of the exposed surface of the cornea by a laser beam at different depths; Fig. 50 is a front reduced view of the cornea as it was taken along lines 50-50 of Fig. 49; FIG. 51 is a vertical sectional side view taken through the center of the eye showing the universal preform illustrated in FIG. 46 positioned on the exposed surface of the cornea after the exposed surface was removed as shown in FIG. Fig. 49; FIG. 52 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached to the exposed surface of the cornea and the remaining portion of the universal preform illustrated in FIG. Fig. 46 when they are excised by the laser beam as shown in Fig. 51; Fig. 53 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform illustrated in FIG. Fig. 46 after a central portion of the universal preform and a central portion of the exposed excised surface were excised by a laser beam; Fig. 54 is a vertical sectional side view taken through the center of the eye showing the cornea _? the fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform illustrated in Fig. 46 whose periphery was excised by a laser beam; Fig. 55 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform after which a portion of the periphery of the universal preform and a portion of the excised exposed surface surrounding the remaining portion of the preform were excised by a laser beam; Fig. 56 is a vertical side view in section taken through the center of the eye showing the cornea and the fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform illustrated in FIG. Fig. 46 excised by the laser beam asymmetrically; FIG. 57 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached to the exposed surface of the cornea and the remaining portion of the universal preform shown in FIG. Fig. 46 after a portion of the universal preform and a portion of the exposed excised surface were excised by a laser beam asymmetrically; Fig. 58 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached on the exposed surface of the cornea and the remaining portion of the universal preform shown on the Fig. 46 of which multiple portions were excised by a laser beam; and Fig. 59 is a vertical sectional side view taken through the center of the eye showing the cornea and the fin-shaped portion reattached to the exposed surface of the cornea and the remaining portion of the universal preform shown in FIG. Fig. 46 after multiple portions of the universal preform and multiple portions of the excised portion of the exposed surface were excised by means of a laser beam; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 is a vertical sectional side view taken through the center of an eye comprising a cornea 12, a pupil 14 and a lens 16. If the cornea 12 and lens 16 do not adjust the light together correctly in the retina (not seen) of the eye to thereby provide adequate vision, the curvature of the cornea can be modified to correct the refractive power of the cornea and thus correct the way in which the light is adjusted with respect to to the retina.
A universal preform 18 in accordance with an embodiment of the present invention is illustrated in Figs. 2-4. As shown, the universal preform in accordance with this embodiment is disk-shaped and has a totally uniform or substantially uniform thickness, as specifically illustrated in Fig. 3. Specifically, the preform 18 has a first flat surface 15 or substantially flat, a second flat surface 17 or substantially planar and a periphery 19. The surfaces 15 and 17 are placed in parallel or substantially parallel to each other with the periphery 19 being positioned perpendicular or substantially perpendicular to one or both surfaces 15 and 17. Of course, the surfaces 15 and 17 and the periphery 19 do not need to be uniform but could have cavities, projections, raised portions or any variation of shape and texture. Preferably, the universal preform 18 has a diameter of about 4 to about 9 mm and a thickness of about 20 to about 500 microns. Of course, the diameter and thickness of the disk-shaped universal preform 18 can have any practical size as one skilled in the art would appreciate. In addition, the universal preform need not have a disc shape, although it is preferred as shown by the embodiment of Figs. 2-4, but may have a frusto-conical, oval, square, rectangular shape or any practical form as one skilled in the art would appreciate immediately. Preform 18 is preferably made of synthetic material, organic material or a combination of both materials, which allows all light or substantially all light with a wavelength in the visible spectrum to pass through, but which absorbs all light or substantially all the light with wavelength of a laser beam spectrum. For example, the preform 18 may be made from collagen, collagen copolymers, polyethylene oxide or hydrogel or a degraded organic material such as collagen, hyaluronic acid, mucopolysaccharide or glycoprotein to name a few. The preform 18 is porous to allow oxygen and nutrients to pass through it. In addition, the preform 18 can be made from a cornea donated from a human eye or can be taken from a cultured cornea. However, the preform 18 is not limited to those materials and can be made by any suitable material such as those disclosed in U.S. Patent No. 4,994,058 to Raven et al., U.S. Patent No. 4,718,418 to L '. Esperance, U.S. Patent No. 5,336,261 to Barrett et al., U.S. Patent No. 4,840,175 to Peyman and a publication of Dr. Jose I. Barraquer, entitled "Keratomileusis and Keratophakia in the Surgical Correction of Aphakia". (The Keratomileusis and the Keratofachia in the Surgical Correction of the Afaquia) whose disclosures are included herein by reference herein The preform 18 is configured to be placed directly on an exposed inner surface of the cornea of the eye. In the inner surface of the cornea of the eye, a thin layer of the living cornea should be removed.To remove the layer of the cornea, a procedure is carried out in which, for example, In this case, an incision 20 is made in the front portion of the cornea, as shown in Fig. 5. This incision 20 is made so that the thin layer 22 of the cornea is separated from the remaining portion of the cornea 12. The incision can be made with a scalpel, keratome, excimer laser or any type of cutting surgical instrument that is known to those skilled in the art. The layer 22 can also be separated from the surface of the living cornea by any other method that does not include making a real incision in the cornea as one skilled in the art can appreciate. The layer 22 of the cornea can be completely removed from the remaining portion of the cornea 12. However,, as it appears in Figs. 5 and 6, it is preferable that the cornea layer 22 remains attached to the main portion of the living cornea 12 by means of a attached or pendant portion 24. Therefore, as shown in Fig. 7, the layer 22 of the cornea It is formed of a fin-shaped layer that can be rotated about the attached portion 24 to expose an inner surface 26 of the cornea. The layer 22 can typically have a practical thickness, for example, 160 microns. The universal preform 18 is then used to modify the curvature of the cornea in the following manner: As shown in Figs. 8 and 9, the fin conformal layer is positioned so as to expose the inner surface 26 of the cornea. The preform 18 is then placed on the exposed surface of the cornea in a position that the person performing the corneal modification technique considers appropriate. Typically, as shown in Fig. 10, the preform 18 is positioned centrally or substantially centrally on the exposed surface 26 with the central longitudinal axis of the preform substantially coincident with the optical central axis of the eye. Of course, the preform 18 need not be placed centrally on the exposed surface 26 as shown, but rather, its longitudinal central axis may deviate from the optical central axis of the eye. Once it is placed on the exposed surface 26 of the cornea 12, the shape of the universal preform can be modified enough to shape the fin-shaped layer 22 and thereby change the refractive power of the shaped layer. fin enough to correct the abnormality of the eye 10. In general, each corneal curvature change of 10 microns will change the refractive power of the cornea by 1 diopter. For example, as shown in Figs. 11-14, a laser beam L is directed to the first upper surface 15 of the preform 18 which is opposite the second lower surface 17 of the preform 18 which is supported on the exposed surface 26 of the cornea 12. The laser beam L it can be emitted from any type of laser 27"or that described in U.S. Patent No. 4,840, 175. As shown in FIG. 12, the laser beam L will begin to excise an area 32 of the preform 18 toward Where the laser is directed Again, the area of the preform 18 to which the laser beam L is directed and which is excised is selected to remedy a specific type of abnormality that the eye is suffering, for example, if the preform is used to correct a hyperopic or hypermetropic condition, the laser beam L will be directed towards the central area 32 of the preform 18 to remove that central area 32. As shown in Fig. 13, for example, the preform 18 is disk-shaped , and the area 32 that is removed is circular in the top plan view and at least at the beginning has a substantially hemispherical cavity shape. Of course, the shape of the excised area may have any desired shape necessary to effect the correction of the particular abnormality of the eye. As mentioned above, the preform 18 is made of a material that will absorb all or substantially all of the light having a wavelength within the laser light spectrum. Therefore, when the laser beam L is irradiated to the preform 18, no or substantially no laser beam will pass through the preform 18 by removing some portion of the cornea 12. However, as also mentioned above, the material of the preform 18 will allow that all or substantially all light with wavelength within the visible spectrum of light passes through it. Therefore, as shown in Fig. 14, the laser beam L can be directed to the preform 18 until the excised center area 32 is an orifice with a frusto-conical wall that completely traverses the preform 18 to expose a portion 34 of the surface 26 of the cornea 12. Of course, the hole may have a cylindrical or substantially cylindrical wall, or any other form that produces the laser beam L. As shown in FIG. 14, nothing or essentially nothing of the surface 26 of the cornea is removed by the laser beam. After the extirpation process is finished, the corneal-shaped layer 22 of the cornea is repositioned on the remaining portion of the preform 18 and the surface 26 of the cornea 12 as shown, for example, in FIG. 15. According to the illustration, the shape of the remaining portion of the preform 18 will shape the flap-like layer 22 when this layer is replaced over the remaining portion of the preform 18 and the surface 26 of the cornea 12. Hence, the refractive power of this flap-shaped layer 22 changes due to this change in shape. The fin-shaped layer 22 can be reattached to the cornea 12 by any technique known as suture or equivalent. Because the material of the preform 18 is transparent or essentially transparent to light with a wavelength within the visible light spectrum, the visible light will traverse the remaining portion for the preform 18 and enter the eye 12. However, because the fin-shaped layer 22 with a new shape has a different refractive power, this layer 22 will refract the light that passes through it differently than before having a new shape. Therefore, "in cooperation with the lens 16 (see Fig. 1), this new shaped layer 22 will adjust the light appropriately in the retina, thereby correcting the ametropic condition of the eye. The laser 27 can be used to reduce the overall thickness of the preform 18 prior to the modeling of the preform For example, the preform 18 can initially have approximately 500 microns thick to facilitate its handling. placed on the exposed inner surface of the cornea in the manner already described, the laser beam L can be directed to the upper surface 15 of the preform to reduce the overall thickness of the preform 18 as appropriate.Therefore, a preform of approximately 500 microns Thickness can be reduced, for example, to about 100 microns or to any convenient thickness, by the laser beam X, before this beam is used to model the preform 18 to a par shape particular as shown, for example, in Figs. 11-15. In addition, based on the severity of the abnormality of the eye, it can be determined that the surface of the cornea has a new, more extensive shape. In this case, as shown in Fig. 16, the laser beam L can be irradiated in the area 32 of the preform 18 until the area 32 of the preform 18 is completely removed by the laser beam and a hole is made that completely traverses the preform 18. Then the beam Laser L is directed to the exposed portion of the surface 26 of the cornea to remove a portion 36 of that surface. Accordingly, as shown in Fig. 17, when the flap-like layer is repositioned on the remaining portion of the preform 18 and the surface 26 of the cornea 12, the excised portion 36 of the cornea surface 26 will also shape the newly affixed flap shape layer 22. By using this technique, it is not necessary for the thickness of the preform 18 to change to provide a more substantial change in the shape of the flap-like layer. Alternatively, if the preform 18 is used to correct a condition of excessive myopia, the laser beam L can be directed towards the outer perimeter of the preform as shown for example in Figs. 18-21. As already mentioned, the preform 18 is made of a material that will absorb all or substantially all of the laser beam. Therefore, as shown in Fig. 19, specifically, the preform 18 will be excised by the laser beam, but nothing or substantially nothing of the surface 26 of the cornea 12 below the excised area 38 of the preform will be excised. The laser beam L can be irradiated in the excised area 38 of the preform 18 until the area 38 is excised below the surface 26- of the cornea where the preform 18 is placed., and the remaining portion of preform 18 thus has a frusto-conical shape. Of course, the laser beam L can give any shape to the preform 18. Then, as shown in Fig. 22, the flap-like layer 22 is again placed on the remaining portion of the preform 18 so that the remaining portion of the preform 18 shapes the newly-shaped fin-shaped layer 22. As the material of the preform 18 is transparent or substantially transparent to light with a wavelength in the visible light spectrum, visible light It will pass through the remaining portion of the preform 18. However, since the fin shaped flap 22 has a different refractive power, the fin-shaped layer 22 will refract the light that passes through it differently prior to the new modeling . Therefore, in cooperation with the lens 16 (See Fig. 1), this new shaped layer 22 will adjust the light appropriately in the retina, thereby correcting the ametrophic condition of the eye. "If a modification is needed. In addition to the shape of the cornea to correct a more serious atrophic condition, the laser beam L can be directed towards the surface 26 of the cornea 12 to remove a portion 40 from the surface 26 as shown, for example, in Fig. 23. As shown in Fig. 24, when the flap-like layer is repositioned on the remaining portion of the preform 18 and the surface 26 of the cornea 12, the excised portion 40 of the surface 26 will also shape the the flap-like layer 22 which was replaced again.Therefore, the thickness of the preform 18 needs to be increased to increase the degree to which the flap-shaped layer 22 received a new shape.The conditions of excessive myopia of up to 35 diopters they can be corrected using this technique. As mentioned above, any portion or portions of the preform 18 can be excised to a degree necessary to correct the ametropic condition of the eye. For example, as shown in Figs. 25 and 26, the laser beam L can be directed towards a central area 32 of the preform 18 and also towards the 38 of the preform 18 to remove the inner and outer areas 32 and 38. As shown in Fig. 27, when the Fin-shaped layer 22 is repositioned on the surface 26 of the cornea 12 and the remaining portion of the preform 18, the remaining portion of the preform 18 will shape the fin-shaped layer 22. As also shown in FIG. Fig. 28, any portion or amount of exposed surface of the cornea 26 can also be excised, provided there is a sufficient amount (e.g., 200 microns) of cornea so that the remaining cornea does not experience instability or lack of convexity (eclasia ). As illustrated, the laser beam L can be directed towards the surface 26 of the cornea below the excised portions 32 and 38 of the preform 18 to remove those portions 36 and 0 from the surface 26 of the cornea 12. Therefore, as shown in FIG. shown in Fig. 29, the remaining portion of the preform 18 and the excised portions 36 and 40 of the surface 26 of the cornea 12 will shape the flap-like layer 22 when this layer is replaced over the remaining portion of the preform 18 and the surface 26 of the cornea. As illustrated in FIG. 30, the laser beam L can be directed towards the preform 18 to remove the preform asymmetrically. This type of modeling of the preform 18 is usually done to correct a condition of astigmatism in the eye. For example, the preform can be sculpted to obtain a substantially hemispherical shape that looks like an egg half when an egg is cut along the longitudinal axis. In other words, the preform 18 can assume a substantially hemispherical shape with a variable radius. As can be seen in Fig. 31, only a portion 42 of the right lateral periphery of the preform 18 is removed., as shown in Fig. 32, the remaining portion of the preform 18 will shape the flap-like layer 22 when this layer is repositioned on the remaining portion of a preform 18 and the surface 26 of the cornea. As shown in Fig. 33, any portion or amount of the exposed surface of the cornea 26 can also be removed asymmetrically, provided there is a sufficient amount of cornea (approximately 200 microns) so that the remaining cornea does not experience instability or lack of convexity (eclasia). In this case, the laser beam L is directed to the portion of the disc 18 to be excised and after the portion is excised, the laser beam L is directed to the surface of the cornea 26 below the excised portion of the preform similarly to that described, for example, in Fig. 16 until a portion 44 of the surface 26 is excised. Then, as shown in FIG. 33, the flap-like layer 22 is repositioned on the remaining portion of the preform 18 and the surface 26 of the cornea so that the remaining portion of the preform 18 and the portion excised 44 from the surface 26 of the cornea 12 form the fin-shaped layer 22. Fig. 34 shows another embodiment of the method for using a universal preform in accordance with the present invention. that the fin-shaped layer 22 was placed as shown in Fig. 7 to expose the surface 26 of the cornea, that surface 26 can be excised by a laser beam before the preform 18 is placed on it. the laser beam L is directed towards that exposed surface 26 to remove the cornea 12 at a particular depth, Typically, as the thickness of an average cornea is approximately 500 microns, the surface 26 can be excised at any amount to a depth of approximately 300 microns, which would leave a sufficient amount (for example, approximately 200 microns) of remaining cornea so that it does not experience instability or lack of convexity as already mentioned. The excised section 46 of the surface 26 may be symmetrical about the center of the front portion of the cornea as shown in Fig. 35. Preferably, the shape of the excised section 46 will match the shape of the preform 18 that is use to modify the cornea. In the example given in Fig. 36, the preform 18 is disc-shaped and therefore, the section extirpated 46 is circular. In addition, the diameter of the excised section will coincide or substantially coincide with the diameter of the disc 18. Of course, the shape of the excised section 46, for example, can be symmetrical and can vary to accommodate * a disc having any shape as want an expert of the technique. In addition, the center of the excised section does not need to coincide with the optical axis of the eye, but rather could deviate from the optical axis. The edge 48 of the excised section 46 will abut the periphery 19 of the disc as shown in Fig. 36, thereby preventing or substantially preventing the disc 18 from moving laterally on the surface 26 of the cornea. However, the edge 48 does not need to come into contact with the entire periphery 19 to perform this function.
As shown in Fig. 37, the disc 18 can be excised as discussed above in Figs. 11-14 so as to form a cavity or hole in the center or "substantially in the center of the preform 18. In the example shown in Fig. 37, the excision is stopped in the exposed section extirpated 46 from the surface 26 so that no or substantially no part of the excised section 46 is excessively removed.The flap-like layer 22 is then placed back on the remaining portion of the preform 18 so that the remaining portion of the preform 18 and the central portion 50 of the exposed excised section 46 shape the re-shaped fin-shaped layer 22. Alternatively, as shown in Fig. 38, the laser beam L can be directed towards the preform 18 and the exposed section extirpated 46 in the form similar to that described earlier in Fig. 16. In doing so, a portion 52 of the excised section 46 of the exposed surface 26 is further excised.The excised section 46 can be excised in any amount as long as it is left in place. sufficient amount (for example, approximately 200 microns) of cornea 12. In this example, the remaining portion of preform 18 and excised portion 52 of the excised exposed section 46 shape the fin-shaped layer 22 when this layer is replaced. on the preform 18 and the exposed surface 26 of the cornea.
As shown in Fig. 39, the periphery of the preform 18 can be excised in a manner similar to that discussed in relation to Fig. 21. As seen, nothing or substantially nothing of the previously excised surface 46 of the exposed surface 26 It is removed by the laser beam. Accordingly, as shown in Fig. 40, the remaining portion of the preform 18 and the excised section 46 of the exposed surface of the cornea give shape to the flap-like layer 22 when this layer is again placed over the preform and the exposed surface 26. Alternatively, as shown in Fig. 41, a portion 54 of the excised section 46 of the exposed surface 26 may be further removed by the laser beam. In this case when the flap-like layer 22 is repositioned on the exposed surface 26 and the remaining portion 18 of the preform, the excised portion 54 and the remaining portion of the preform 18 shape the flap-shaped layer. 22. As further shown in Figs. 42 and 43, a portion of the preform 18 alone or a portion of the preform 18 and a portion 56 of the excised section of the exposed surface 26 of the cornea may be excised asymmetrically. Accordingly, when the flap-like layer 22 is repositioned on the exposed surface 26 and the remaining portion of the preform, the shape of the remaining portion of the preform 18 and the excised portion 56 shape the shaped layer. of fin 22. Also, as shown later in Figs. 44 and 45, multiple portions of the single preform 18 or multiple portions of the preform and multiple portions 58 of the excised section 46 of the exposed surface 26 can be excised by the laser beam. Accordingly, the remaining portion of the preform 18, and the excised portions 58 of the excised section 46 of the exposed surface give shape to the flap-like layer 22 when this layer is replaced over the remaining portion of the preform 18. and the exposed surface 26. Another embodiment of the universal preform in accordance with the present invention is shown in Figs. 46-48. Specifically, the preform 60 shown in Fig. 46 has a large portion 62 and a small portion 64. The large portion 62 can have any practical shape and size as could the preform 18 shown in Fig. 2, and can be made from the same type of materials as the preform 18. In the example shown in Fig. 46, the large portion 62 of the preform 60 has a disc shape and a diameter of about 4 to about 9 millimeters and a thickness - between approximately 20 and approximately 500 microns. Of course, the diameter and thickness of the preform 60 can have any practical size desired by a person skilled in the art. As illustrated later in Figs. 47 and 48, the small portion 64 of the preform 60 is also disk-shaped but has a smaller diameter than the large portion 62. The diameter of the small portion 64 can be of any practical size, such as that of a shaped projection. of small disk with a nominal diameter of up to a disk-shaped projection with a diameter of only a fraction smaller than the diameter of the large-shaped portion 62. Of course, the small portion 64 need not have a disk shape provided that it has a practical form that one skilled in the art desires. In addition, the large portion 62 and the small joke 64 may have different shapes from each other. Thus, for example, the large portion 62 may have a disk shape while the small portion 64 may have an oval or rectangular shape. The large portion 62 has a first flat or substantially flat surface 63, a second flat or substantially planar surface 65 and a periphery 66. The surfaces 63 and 65 may be parallel or substantially parallel to each other, and the periphery 66 may be perpendicular to one. or both surfaces 63 and 65. Of course, the surfaces 63, 65 and the periphery 66 need not be uniform but may have projected portions, cavities, or any type of texture. The small portion 64 is part or is attached to the large portion 62 and a flat or substantially planar surface 68 and a periphery 69. The surface 68 may be parallel or substantially parallel to one or both surfaces 63 and 65 of the large portion 62. , and the periphery 69 could be perpendicular or substantially perpendicular to the surface 68. Of course the surface 68 and the periphery 69 need not be uniform but may have projected portions, cavities or any type of texture. In Fig. 49 an embodiment of a method for using the universal preform 60 in accordance with the present invention is shown. Specifically, the surface of the cornea 26, which was exposed by forming and placing the fin-shaped layer 22 in the manner discussed above, is excised as shown in Fig. 49. That is, the exposed surface 26 is excised at different depths to take a shape where the preform 60 can be accommodated. Therefore, an outer section 70 is removed from the exposed surface 26 at a first depth, while an inner section 71 is excised at a second depth greater than the first . The depths of the inner and outer excised sections 70 and 71 can be any amount that allows a sufficient amount of excess cornea 12 (for example, about 200 microns) so that the remaining cornea does not "experience deformation or lack of convexity. notes that this step-shaped preform 60 provides an advantage over a preform 18 with uniform shape, since less volume of cornea can be removed to form a cavity that will accommodate the small portion 64 of the preform 60 and thereby signals the preform 60 the change on the surface of the cornea, ie the volume of the cornea removed to form section 71 is less than the volume of cornea removed to form section 46 (Fig. 34) As shown in Fig. 51, the preform 60 is placed over the excised sections 70 and 71 of the exposed surface 26 so that the surface 68 of the small portion 64 of the preform 60 comes into contact or its substantially comes into contact with the excised section 71 while the surface 65 of the large portion 62 of the preform 60 comes into contact or substantially comes into contact with the excised section 70. As can also be seen, an edge 72 of the excised section 71 comes into contact with the periphery of the large portion of the preform 60, while an edge 74 of the excised section 71 comes into contact with the periphery 69 of the small portion 64 of the preform 60. Of course, the sizes and shapes of the excised section 70 and 71 can be made to adapt or substantially adapt to the sizes and shapes of the large and small portions 62 and 64, respectively, of the preform 60, and thereby may have any size and practical shape as desired by one skilled in the art. In addition, the excised sections 70 and 71 do not need to have symmetry around the optical central axis, but could deviate from the optical central axis of the eye and each other. The edges 72 and 74 of the excised sections 70 and 71, respectively, may come into contact with the peripheries 66 and 69, respectively, in their entirety or in several places. As shown later in Fig. 51, the laser beam L is irradiated on the preform 60 in a manner similar to that described with respect to Figs. 11-14 to remove a central or substantially central portion of the preform 60 as shown in Fig. 52. For example, the excised portion may be a substantially hemispherical cavity as discussed above with respect to Figs. 11-14. As also shown in Fig. 52, no or substantially no part of the excised section 71 was excessively removed by the laser beam. Accordingly, the surface of the excised section 71 and the remaining portion of the preform 60 shape the fin-shaped layer 22 when this layer is repositioned on the preform 60 and the exposed surface 26. Alternatively, as shown in Fig. 53, a portion 76 of the excised section 71 below the excised portion of the preform 60 can be further excised by the laser beam at any depth that allows enough of the cornea 12 to remain (for example, approximately 200 mieras). Accordingly, the excised portion 76 and the remaining portion of the preform 60 shape the flap shape layer 22 when this layer is repositioned on the exposed surface 26 and the remaining portion of the disc 60. As shown below in Fig. 54, multiple portions of the preform 60 can be removed in a manner similar to that described for the preform 18 in the above Figs. 18-22. Furthermore, as shown in Fig. 55, the laser beam can be directed toward the excised section 70 of the exposed surface 26 to remove the portion 78 from the excised section 70. Thus, as shown in Fig. 54, the The remaining portion of the preform 60 and the excised portion 70 shape the fin-shaped layer 22 when this layer is repositioned on the exposed surface 26 and the remaining portion of the preform 60. On the contrary, as shown in FIG. Fig. 55, the remaining portion of the preform 60 and the most excised portion 78 of the excised section 70 of the exposed surface 26, shape the fin-shaped layer 22 when this layer is repositioned on the exposed surface. in the remaining portion of the preform 60. As further shown in Figs. 56 and 57, the preform 60 and the excised section 70 of the exposed surface 26 can be excised by the laser asymmetrically. Accordingly, as shown in Fig. 56, the remaining portion of the preform 60 and the excised section 70 shape the flap-like layer 22 when this layer is repositioned on the surface 26 in the remaining portion of the preform 60. As shown in Fig. 57, the asymmetric excised portion 80 and the remaining portion of the preform 60 shape the fin-shaped layer when this layer is repositioned on the exposed surface 26 in the portion remaining of the preform 60. As shown in Figs. 58 and 59, the preform 60 and the excised section 70 can be excised in multiple places in a manner similar to that described above for the preform 18 and the surface 26 with respect to Figs. 25-29. In consecuense, as shown in Fig. 58, the remaining portion of the preform 60 and the eyelid sections 70 and 71 of the exposed surface 26 shape the fin-shaped layer 22 when this layer is again placed over the surface. exposed surface 26 and preform 60. Alternatively, as shown in Fig. 59, the additionally excised portion 82 of the excised section 70, the further excised portion 84 of the excised section 71, and the remaining portion of the preform 60 and the remaining portion of the preform 60 gives shape to the fin-shaped layer 22 when this layer is repositioned on the remaining portion of the preform 60 and the exposed surface 26. Although only some embodiments of this embodiment were described in detail. invention, those skilled in the art will readily appreciate that many modifications can be made to exemplary embodiments without departing materially from the teachings and new advantages of the invention. This invention. Accordingly, it is intended to include all modifications within the scope of this invention as defined in the following claims.