KR20000069361A - Method and Apparatus for Adjusting Corneal Curvature Using a Corneal Ring With Removable Biocompatible Material - Google Patents

Abstract

An adjustable intrastromal device is provided that is suitable for implantation into the cornea and is formed of a flexible hollow shell 30a that is implantable into the cornea while surrounding the central visual area of the cornea. The implant may be a compartment 117 of various forms of solid biocompatible material, such as solid rings 38 or strands of flexible polymeric material of various shapes and lengths, or alternatively perforated shells 107. In a predetermined amount of fluid, such as saline or gel. The biocompatible filler material is essentially located within the flexible shell to alter its thickness or diameter size, so that the corneal curvature is adjusted to correct for refractive errors. Adjustment of the implant can also be done postoperatively after implantation by selective removal of biocompatible filler material or addition of new material to the device.

Description

Method and Apparatus for Adjusting Corneal Curvature Using Corneal Yun with Removable Biocompatible Material TECHNICAL AND APPARAtus for Adjusting Corneal Curvature Using a Corneal Ring With Removable Biocompatible Material

<Reference to Related Applications>

This application claims U.S. patent application Ser. No. 08 / 761,362, filed Dec. 9, 1996, Ser. No. 08 / 829,846, filed Apr. 1, 1997, and Ser. No. 08 / 856,650, filed May 15, 1997. Claimed as priority, the subject matter of each of these patent applications is fully incorporated herein.

〈Background of the invention〉

The present invention provides a method and apparatus for adjusting corneal curvature, and more particularly, by adjusting or removing a solid material from an implanted device at the time of insertion and after the procedure or with a solid material, suitable for insertion into the cornea of the eye. Implantable devices in which the amount of volume replaced to correct for refractive errors by varying can be varied significantly.

Refractive anomalies, which are undesirable symptoms of refraction of the eye, are subdivided mainly into three myopia, hyperopia and astigmatism. In myopia, the parallel ray 20 entering the eye as shown in FIG. 1 due to the most common type of refraction anomaly focuses F1 before the retina 24 as shown in FIG. 2. In the original, the light beam 20 has a focal point F2 behind the retina as shown in FIG. 2. When the light beam is condensed into several rather than one focuses, it is called astigmatism, in which the various focuses may all be in front of the retina, all focus may be behind the retina, or some may be in front of the retina.

Refractive anomalies are typically corrected by eyeglasses or contact lenses. However, these refractive errors can also be corrected by surgical surgery. Refractive ophthalmic surgery is defined as surgery for the eye that acts to change the optical curvature properties of the eye. Currently more common refractive procedures include radial corneal incisions described in US Pat. Nos. 4,815,463 and 4,688,570 and laser ablation of the corneal substrate described in US Pat. No. 4,941,093. Various other surgical methods have been attempted to correct refractive errors, including heated corneal formation for primordial treatment, corneal epithelial repair to correct severe hyperopia, and corneal curvature that can shave or flatten the central cornea. Corneal curvature was introduced by Barraquer, Columbia, USA, in 1961, which essentially involves crushing and replacing the corneal structure with a reshaped corneal structure that is suitable for correcting refractive errors. Some more common corneal refraction procedures are discussed below, but to date no one has been shown to possess all the features of an ideal corneal refraction procedure. Disadvantages of corneal refractive surgery include limited predictability, lack of reversibility, corneal destabilization, visual field fibrosis, postoperative anxiety, and visual disorders such as glare, halo and flashes. In the radial corneal incision (RK), multiple circumferentially radially incisions are formed in the cornea at a depth of 90-95% in an attempt to correct myopia by flattening the central cornea. The problem of unpredictable results has been revealed by a complex and extensive historical analysis of patients who have already undergone surgery. These studies indicate that certain factors, such as visual area size, initial corneal curvature readings, corneal diameter, corneal hardness, number of incisions, depth of incisions, intraocular pressure, corneal thickness and astigmatism, influence surgical outcome. Shown to appear. Age and gender are also factors to be considered in most nomograms designed to predict what effect would be expected for a particular surgery. In one view, many experts in the field consider it almost impossible to completely and accurately correct patients in a single operation, and RK has performed a "bal-park" correction in two stages of surgery, early surgery. And then an improvement procedure to adjust or titrate results that are close to the desired outcome for the patient's eye must be believed to be followed. This is because, unlike predicted by nomograms, a small percentage of surgeons attempting to completely correct refractive errors in a surgery due to individual differences that can lead to individual under- or over-correction. It seemed to induce excessive correction, making it even more difficult to correct. Unfortunately, the second stage of surgery is less predictable than the initial procedure. No formula has been devised that takes into account significant changes that occur in the cornea after the initial RK, especially weeks or months later. Most studies cite that only 50-60% of eyes achieve 20/20 or have better vision after RK. Patients accustomed to 20/20 or better corrected vision prior to surgery are typically not satisfied by uncorrected postoperative vision of 20/25 or less than 20/30.

In addition, the progressive primordial trend is the main concern after RK. Refractive stability is important for all refractive procedures, but all corneal refractive procedures show a significant degree of instability. To date, there is no clear explanation as to why the cornea is destabilized by RK. Recent reports on the long-term results of RK have highlighted the "natural" primitive refractive development of "normal" eyes as a function of age. Patients are initially overcorrected, but excessive correction can be hidden by the patient's adaptability. Due to adaptation time and its decay, hyperopia may appear progressively impaired as hyperopia. At the time of surgery, the patient may eventually be corrected with some hyperopia but has 20/20 vision due to the adaptability of the lens. There is a range of residual corrections that the patient may have 20/20 of uncorrected vision. This range will vary from person to person but will usually range from two to three diopters. Even in this range, the percentages that make up 20/20 are only 50-60%. This rarely reflects the accuracy of the technology. It is important to note that this range is reduced due to presbyopia, ie adaptation decline, which usually begins around the age of about 45 years. This results in a 20/20 percent reduction in the 50 to 60% described above. It is clear that RK is not recognized as a simple, safe and predictable procedure for adjusting the refractive performance since the initial RK was performed. Most of the thoughts made about the shape of the cornea after this procedure were completely empirical. Therefore, an easy way to fine tune the minimally aggressive and easily performed refractive correction will have to be taken seriously.

Laser substrate incision procedures such as photorefractive incisions (PPK) for correction of refractive errors are currently popular and achieve ideal success. However, these procedures do not solve the problem of unpredictability. Essentially, in myopia treatment, laser energy is imparted to the central cornea, causing more tissue to be excised centrally and flatten the cornea. Unfortunately, the final refractive effect is measured by the amount of incision as well as the therapeutic response to the incision. In an attempt to treat damage to the surface, the cornea actively produces new collagen and epithelial tissue undergoes a proliferative response among other reactions. This leads to a degeneration, which can occur gradually over months to years, i.e. a rapid retrograde into myopia. The undesirable effect of new collagen deposition is substrate scar formation which is evident as substrate haze and can reduce the patient's contrast sensitivity. Opacity of such corneal stroma is variously called fibrosis, wound or dullness and is associated with reduced vision, contrast sensitivity, deterioration of refractive effects and poor night vision. Predictability by PRK is the same issue as by RK. The usually published results of post-PRK treatment for myopia indicated that the percentage of patients making up 220/20 was significantly reduced, with 80-94% of eyes getting 20/40 or better uncorrected visual acuity. This figure exists despite the fact that the patient is in the range of residual refractive power, which can see 20/20 as already explained. A significant proportion of 20/20 after PRK can actually be assumed to be slightly primitive. A significant percentage of patients will develop the appearance of "gradual primitive" or latent primitives over time. For this reason, the percentage of patients 20/20 following PRK may not be tolerated by the definition of an ideal refractive procedure, but may swell together in the initial results with RK. Although vision recovery is slow in RK, it is faster than after PRK. A second laser ablation procedure requires attention because it can typically cause a larger therapeutic response with much more degeneration than the initial procedure. Again, laser ablation, as in RK, is not entirely predictable, in part because no one can predict an individual's wound healing response.

For many years it has been thought that refractive surgery with intracorneal transplantation can be used to correct astigmatism. Recent techniques, such as in corneal curvature and graft grafts, include lamellar removal or addition of natural corneal stromal tissue. They required the use of a microkeratome to remove a portion of the cornea and then to shave the removed cornea of the patient (keratoplasty) or supplier (graft of the graft). The device is complex, surgical techniques are difficult and quite disappointing and the results are quite different. Current corneal refractive surgery seeks techniques to lessen the trauma to the cornea, to minimally stimulate the wound healing response, and to behave in a more predictable fashion. The use of allogeneic intracorneal lenses to correct the refractive state of the eye was first proposed in 1949 by Jose Barraquer, where biocompatibility, nutrient and oxygen permeability and corneal and lens hydrogenation states, etc. I am struggling with problems. Problems with these lenses include the possibility of accompanying internal wounds with surgical manipulation of the central visual axis.

More recent efforts to correct for refractive errors have focused on minimizing the effects of wound healing responses by avoiding the central cornea. Various attempts have been made to alter the central corneal curvature by surgical manipulation of the peripheral cornea. These techniques are discussed because of their particular relevance to the present invention.

In the preface to the Principle and Practice of Refractive Surgery, Jose Barrker said, "As a result of my initial presentation, some writers decided to try different methods to modify the shape of the cornea. Krawawicz. Punch goiter resection of plastic discs and temporal bone encapsulation (1960), the use of trephine by Pureskin (1976), Soto impronata by Strampelli (1964), molding by Martinez and Katsin (1965) and corneal lysis by Blawatkaia were all tried. "

Zhivotosvskii, D. S., US Pat. No. 3887846, describes a homogeneous, flat, geometrically regular, annular ring for intracorneal implantation of inner diameter that does not exceed the diameter of the pupil. Refractive correction primarily creates a radius of curvature of the surface of the annulus to be larger than the radius of curvature of the patient's cornea to flatten the central area of the cornea. Surgical procedures for inserting the rings are not described.

A. B. Reynolds (US Pat. No. 4,452,235) describes and claims corneal refraction techniques related to methods and apparatus for modifying the shape of the visual region of the cornea to correct refractive errors. The method inserts one end of the separating annular incision into the matrix of the cornea, moves the incision in the arcuate passageway around the cornea, and heterogeneously attaches one end of the separating annular adjustment to one end of the incision, Reversibly move the incision around the passageway, pulling the adjustment around the circular passage made by the incision, pulling the incision, and adjusting the ends of the separate annular adjustments to each other to alter the diameter and shape of the cornea. Fixing and anchoring the ends of the rings by adjusting and fixing to maintain the desired local shape of the cornea.

The main benefit of corneal yun was that a very minimal wound healing effect was expected. Prominent corneal wound response will reduce the long term stability of any surgical refractive procedure. However, there are two distinct problem areas that affect the refractive results of surgical procedures for treating refractive errors:

1. The first problem relates to the ability to schedule the shape and size of the graft that will lead to specific refraction results. In RK or PRK, refraction studies have been conducted leading to the development of nomograms that predict that the amount of depth cutting or specific removal will predict the amount of correction. In the case of corneal yun, the nomogram will eventually develop so that it can be used to predict a given refractive correction for a given thickness or size of corneal yun. However, these nomograms may not be responsible for individual differences in response to a given corneal refraction procedure.

2. Refractive results also depend on the stability of the refractive correction obtained after surgery. To repeat, the benefit of corneal lubrication will be the stability of the refraction result obtained due to the predetermined minimal wound healing response. This reduces the difference in the long-term refraction results, but still does not address the problem revealed in the first problem area, and although the results may be stable, the inherent individual differences are likely to be stable inaccurate refraction results.

Another not mentioned argument is that even in transplantation, the surgeon will aim for a slight shortage of myopia as the patient is generally more unhappy by the hypercorrection that appears to be primitive. In addition, the refraction result will be more stable than in RK or PRK, but will be a refraction result that is not stable enough.

Simon (US Pat. No. 5,090,955) alters corneal curvature by injecting into the lamellar of the synthetic gel around the cornea, leaving the visual area intact, reducing the amount of replacement by surgically removing the synthetic gel internally. Surgical techniques for adjusting the final curvature are described.

Siepser (US Pat. No. 4,976,719) includes a fastener in which the adjusting means are attached to a single surgical line, and optionally a retainer ring consisting of a single surgical line that creates a ring of adjustable force. Another annular device is described for flattening or shaving the curvature of the cornea by selectively changing its curvature.

There are several mechanisms in which peripheral manipulation of the cornea affects external corneal curvature. Usually, corneas, such as soft tissues, are nonlinear, viscoelastic, heterogeneous, and exhibit significant strain under physiological conditions. The whole eye is geometrically quite complex, and biomechanical techniques that can systematically model this reality are limited basic methods of inferring small strains (measurement of malformations), homogeneity and linear elastic behavior. Two sample mechanisms will be described briefly below.

A simple example helps to understand the first mechanism. Assume that a loose rope R forms a curve in which the lowest point P exists in the center between two fixed points P1 and P2 as in FIG. 4A. Referring to Figure 4b, the weight w placed on the rope between the center point P and one fixed point will straighten the center of the rope. Corneal C, shown in FIGS. 5A and 5B, is similar to the two fixed points P1 and P2, similar to the border of weight W similar to the eye and intrastromal implant 30, in the cornea present in the periphery of the cornea compared to the central corneal visual region. When inserted, corneal collagen fibers are allowed to escape upwards (21) upwards above the implant and downwards (22) downwards below the implant. This deviation of the cornea around the peripheral implant, necessarily due to volume changes in the peripheral cornea, causes other regions of the cornea to lose "looseness", ie, to be relatively straight, as shown at 23.

The structure of the implant 3 moves together similarly to the two fixed points in FIGS. 4A and 4B of the above example, shaping the central corneal curvature while allowing the rope to flex more at the center, whereas FIG. 6B compared to FIG. 6A The mechanism description of the implant diameter as indicated by the expansion of the implant 30 in the art also flattens the central corneal curvature. This occurs in part because the boundary node at the boundary is not completely fixed. In summary, there is a micro deviation caused by the bulk of the implant 30 itself in the surrounding tissue to slightly flatten the central curvature of the cornea and compress or swell the implant to change the fixed point to reduce corneal curvature. Change it. Compressing or inflating the implant will result in less stable refractive performance because the forces inside or outside the implant against the corneal stroma can also gradually cause lamellar incisions and sweeps of force. More consistent results will be obtained by changing the volume placed in the peripheral cornea, as described by Simon.

The second mechanism is suitably described by J. Barrker in the following quotation. Since 1964 "To correct myopia, one must either remove the thickness from the center of the cornea or increase its thickness at the periphery of the cornea. For primitive correction, the thickness must be added to the center of the cornea or the thickness is removed from the periphery of the cornea." The procedure involving removal has been called "corneal keratoplasty", which further includes the one accepted under the name Keratopakia. Corneal limbus in the matrix produces a more significant effect in flattening the external corneal curvature by "increasing (around) its periphery" by adding bulk to the periphery and increasing the thickness of the corneal yun.

An ideal corneal refraction procedure allows for all the advantages of glasses or contact lenses, i.e. correcting over a wide range of refractions, allowing for accuracy or predictability, allowing reversibility in the case of changes in the refractive state of the eye, and again correcting If there is a need to adjust, the complexity is minimized, technically simplified, low cost, and aesthetically acceptable to the patient. The goal of refractive surgeons is to achieve 20/20 uncorrected vision with long term stability in over 95% of patients. None of the refractive surgery currently available gives this degree of accuracy or stability.

Once again, easy procedures to fine-tune the refractive correction and corneal curvature that are often affected by changes in corneal hydrogenation status, wound healing response, and other unknown factors are not available. Each of these techniques is difficult with a limited degree of precision. An easy way to adjust refractive performance after corneal curvature has stabilized in the disclosure of the present invention is a method of generating minimal irritation of the minimally aggressive method, wound treatment method, which allows for repeated adjustments to the extent deemed necessary, It is described as almost completely reversible. This can make known theories about unpredictability unrealistic and can rely heavily on the nomogram for predicting refractive performance, rendering the application of procedures that cannot be precisely responsible for different responses to the procedure.

<Summary of invention>

According to one embodiment of the invention, a tunable chamber is formed of an annular chamber that can be reinforced with a biocompatible filler material such as polymethylmethacrylate (PMMA) and a flexible hollow shell made of a material such as a silicone or urethane polymer. An in-substrate device is provided. The filler material may be any biocompatible material of annular and flexible elongated filaments of any shape or length, preferably of visible size. The device is filled with a predetermined amount of the biocompatible material and implanted in the cornea around the visual area of the cornea. The corneal curvature is then adjusted by completely removing one or more rings to deform the volume of the device in discrete form to steep the corneal curvature and myopia trend. Such relatively simple adjustments to refractive correction can be performed with commonly available surgical instruments, minimizing postoperative manipulation of the implanted and implanted devices. The device of the present invention is an adjustable and implantable device that includes an outer membrane that forms a fence for recovering filler material, such as multiple rings, for the purpose of correcting refractive anomalies and is adapted to be inserted into the lamellar space of the corneal matrix. . The volume replaced by the device is easily deformed in many cases following initial implantation surgery and also does not require removal of the implanted device, allowing for later adjustment of refractive performance.

According to another embodiment of the present invention, the conditioning is formed of a flexible hollow shell made of a material such as silicone or urethane polymer and a chamber adapted for implantation into the cornea and filled with a biocompatible material such as saline or gel. Possible in-substrate devices are provided. Preferably, the device has at least two compartments in which the water is tight and separated from the other compartments. Each compartment contains the described amount of biocompatible fluid, and the device is inserted into the cornea around the visual area of the cornea. As the volume replaced by the ring increases, the anterior corneal curvature is flattened to correct myopia. Preferably, myopia makes the cornea more flat by slightly overcorrecting than necessary for optimal vision. The corneal curvature is then adjusted after implanting the device into the cornea by selectively removing fluid from the specific compartment and reducing the volume of the implant in discrete form to scrape the corneal curvature and cause myopia.

Implants according to various embodiments are readily adjustable in many cases following initial implantation surgery and also do not require removal of the implanted device and allow for later adjustment of the refractive results.

1 is a schematic diagram showing a horizontal cross section of a human eye.

Figure 2 is a schematic diagram showing how the light beam focuses in front of the eye film in myopia symptoms.

Figure 3 is a schematic diagram showing how the light beam focuses in front of the eye film in myopia symptoms.

4A is a schematic diagram showing a rope suspended at its distal end between two fixed points.

FIG. 4B is a schematic diagram of the rope in FIG. 4A showing the force of the ropre applied weight between one of the center point and the fixed point.

5A is a schematic representation of the cornea of the eye where the cornea is stuck to the opposite point on the perimeter boundary.

FIG. 5B is a schematic diagram similar to FIG. 5A showing the curvature effect induced in the cornea due to the presence of an intrastromal support implant in the cornea. FIG.

6A and 6B are schematic cross-sectional views of the cornea to show the effect caused by the swelling of the adjustable implant of the present invention following implantation of the implant of the present invention in the cornea.

7A is a top view of the flexible device of the present invention, in which the device is assisted by radial cutting.

FIG. 7B is an enlarged view of the opposite cross section taken along section line 7b-7b in FIG. 7A.

8A is a cross-sectional view of the apparatus of the present invention.

8B is an enlarged view of the radial section of the tubular device of the present invention with the interior of the device being filled with multiple rings.

FIG. 8C is a cross-sectional view similar to FIG. 8B but with some of the rings shown in FIG. 8B removed from the device.

FIG. 9 is a cross-sectional perspective view of the device of the invention showing the angle of the radial cross section in the form of a cone.

10A-10D are radial cross-sectional views of a modified form of the device of the present invention.

11 is a plan view showing possible ring connection arrangements along a ring located within the implant.

12A and 12B are cross-sectional views of the cornea and device before and after the link ring located within the implant is cut.

13A and 13B are cross-sectional views of the cornea and device before and after the ring is removed.

14A is a radial cross-sectional view of the device of the present invention, showing typical size.

FIG. 14B is an enlarged view of the radial section of the device in FIG. 14A with the interior of the device filled with several rings.

FIG. 14C is an enlarged view of a radial cross section similar to FIG. 14A but showing that the inside of the device is filled with fewer rings having opposite thicknesses on the opposite side.

FIG. 15A is an exaggerated spaced plan view to schematically depict and illustrate the orientation and shape of a plurality of ring materials that may be inserted into the interior of the device. FIG.

15B and 15C are cross-sectional views of the device of the present invention taken along section lines b-b and c-c in FIG. 15A, respectively.

16A, 16B and 16C show changes in the structure and orientation of rings suitable for insertion in a device.

17A is a plan view schematically showing the device of the present invention with a partial ring inserted in the device; FIG. 17B shows a radial cross section of the device of FIG. 17A taken along section line 17b-17b.

17C is a radial cross-sectional view of the device in FIG. 17A taken along section line 17c-17c.

18A is a cross-sectional view of the ring of the present invention with the chamber divided vertically.

18B is a cross-sectional view of the ring of the present invention with the chamber divided horizontally.

18C is a cross-sectional view of one embodiment of a ring with a reinforced inner wall.

19A is a top view of the ring showing two chambers not fully extending around the ring.

19B is a top view of the ring showing two chambers all fully extended around the ring.

20A is a cross-sectional view of one embodiment of a ring having a chamber divided horizontally.

20B is a cross-sectional view of one embodiment of a ring in which the upper chamber is perforated.

20B is a cross-sectional view of the ring of FIG. 20A with the upper chamber perforated.

21 is a radial cross-sectional view of one embodiment of this ring, showing the typical size of the ring.

22A is a cross-sectional view of one embodiment of a ring containing two expanded chambers detachable from the outer shell of the ring.

FIG. 22B is a cross sectional view showing that the thickness of the ring is reduced from FIG. 22A after one chamber is drilled.

FIG. 22C is a cross sectional view of the ring showing further reduced thickness of the ring from FIG. 22B after the puncture chamber has been removed from the implanted ring.

FIG. 23A is a cross-sectional view of one embodiment of a ring showing three microcapsules containing a fluid. FIG.

FIG. 23B is a plan view of the loop showing two openings in the hole or through and separation regions of the ring in the wall of the ring; FIG.

24A-24D are radial cross-sectional views of a modified form of the ring of the present invention.

24E is a cross-sectional view of a ring with a combination of fluid chamber and strand material.

25A and 25B show cross-sectional views of corneas and rings before and after the chamber is perforated.

FIG. 26A is a top view of another embodiment of a ring showing the location of an isolated compartment. FIG.

FIG. 26B is a cross-sectional view of the ring in FIG. 26A taken along section lines 26a-26a.

FIG. 26C is a cross sectional view of the ring in FIG. 26A taken along section lines 26b-26b, showing a relatively thin wall.

FIG. 26D is a cross sectional view of the ring in FIG. 26A taken along section lines 26b-26b, showing a thicker wall as compared to the ring cross section in FIG.

More specifically referring to the figures, FIG. 7A is an apparatus of the present invention that includes an adjustable device 30. Apparatus 30 can easily remove fillers such as stranded materials made of natural or synthetic polymers, including polyester, nylon, polypropylene, polyimide, fluoropolymer materials, and materials used in the manufacture of optical fibers. Form a fence to accommodate. The device filler material may be any biocompatible material but is preferably a flexible filament structure that may be made from an elastomeric material as described above. Rings and strands are used interchangeably herein. The cross section of the ring may be of various structural shapes, including round, oval, rectangular, square or triangular. The cross-sectional area of the ring can vary in length with length. The device may contain one or more rings, each of which may later be removed.

The device 30 includes a tubular shell 30a made of a flexible material such as silicone, acrylic or urethane polymer and is shown as a split donut shape in FIG. 7A. The shell material has adequate stiffness to maintain a generally circular shape in the top view when the device is sufficiently filled, and also increases in thickness when filled as shown in the cross-sectional view of FIG. 8B and the ring is removed as shown in FIG. 8C. When appropriate, it is flexible enough to be flat. The shell of the device should generally have sufficient structural integrity, strength and flexibility to maintain and expand its circular shape. The composition material thereof may be similar to that used to make collapsible or deformable eyepieces such as silicone polymers, urethane polymers or acrylic polymers, or materials used in soft contact lenses or materials such as fluoropolymer resins. Examples of other medical devices comprising materials suitable for the shell of the present invention include vascular graft tubing, dialysis tubing or cell membranes, blood oxidizer tubing or cell membranes, and ultrafiltration cell membranes. The shell or filler material of the device may comprise one or more natural or synthetic polymers.

The cross section of the device 30 taken radially through the center of the implant is an elliptical shape as shown in the cross sectional views shown in FIGS. 8A and 9. The different embodiments shown in FIGS. 10A-10D are each modified to allow the device material from the cross-sectional area in the form of a composition material of the device wall, the manner of connection of the device, the type of ring filler material, and for example in the form of a circle, square, rectangle, oval or the like. A number of sub-embodiments can be provided by changing variables such as surface parameters on the cross section of the device forming the device. As shown in FIG. 7B, the major axis 39 of the cross section of the device 30 forms a cone curve corresponding to the slope of the corneal arch of the anterior pole of the cornea. The angle is about 25 to 35 degrees. The two ends 45, 46 of the device can be parallel to one another as shown in FIG. 7A and the ends coincide so that they can be fixedly fixed during surgical operation by methods such as suture or tight contact.

The device 30 is suitable for implantation into the peripheral stromal cornea. When implanted, the thickness and geometry are adjusted to change the central corneal curvature without invading the central visual area of the cornea, reducing the spread of nutrients to the central cornea. It is easily sized into the matrix into the surrounding human cornea and is sized to include a flexible material that is biocompatible and more specifically suitable for eye tissue. As shown in FIG. 7B, the dimensions have a thickness 45 of 0.1-1.5 mm, a width 56 of 0.4-2.0 mm and an outer total diameter 57 of 3.5-12.00. The thickness of the shell 30a of the device 30 may vary as shown in FIGS. 10A-10D. The device may contain single or multiple rings 38 of varying diameters and compositions. The ring 38 may comprise a permanent biocompatible material used in ophthalmic surgery such as polymethylmethacrylate, nylon, polyester or polypropylene and may vary in diameter from 0.02 mm to 1.0 mm. The rings can be transparent or colored. The loops are marked with the top and bottom of the device to assist the surgeon in adjusting the tension when connecting the ends of the rings. The ring has prefabricated loops 66 and 67 at one end as shown in FIG. 11 to facilitate removal of the ring by using a mechanism with a small hook at the operating end where the loop can be hooked up. Instead of a loop, the ring end may also have some other structure, such as a round or thick end that facilitates holding the ring. In addition, the loop provides resistance at the open end to prevent peripheral rings from being removed at the same time. The two ends of the ring need not necessarily be connected.

The device of the present invention is designed to be implanted in the cornea of the eye so that it does not invade the visual area and alters the external curvature of the central visual area of the cornea. This is a changeable interior in which the visual area is flattened by separating the rings connected by tension, or is suitable for providing the necessary refraction correction and the curvature is sharpened by the removal of the rings in an amount that controls overcorrection or thermal correction of the refraction error. And a cavity device having a volume.

Appropriate embodiments are selected in which the shape, size, circumference, filler material dimension, and filler material composition vary depending on the degree of refractive error. The amount of volume displacement by the device in the lamellae channel, the diameter of the lamellae channel, the width of the channel, the depth and position of the channel are all parameters that affect the refractive change achieved by the device. The flexible shell 30a containing the ring material may also vary as shown by the embodiment of the implant illustrated in FIGS. 10A-10D.

It is selected as follows.

1. Absence of Supported Polymethylmethacrylate (PMMA) Backbone.

2. PMMA or other physiologically acceptable rigid polymer backbone that strengthens the inner circumference of the device wall as shown in FIG. 10C. The thickened region 64 as shown in FIG. 10C may be increased in thickness of the flexible material comprising the wall or may be the rigid polymer backbone described above. During surgery, the inner circumferential skeleton can be almost controlled and fixed by sutures or adherence, and totally by the use of the corneal system.

3. PMMA or other rigid polymer backbone that reinforces the outer circumference of the device wall as shown in FIG. 10B.

4. Supports for inner and outer circumferences.

The size of the device selected should be such that the extent of secondary or thermal correction for the individual variability of the response to surgery is easily corrected by the method described above. The maximum thickness, circumference and type of support skeleton is selected before insertion of the implant. An ideal embodiment in which preoperative refractive states and other relevant data are provided is selected prior to surgery, whereby the embodiment is further adjusted to the extent necessary to determine abnormal curvature. The device is inserted into the peripheral cornea at an appropriate depth and then further adjusted to more precisely control the shape of the cornea and to focus the light entering the eye on the retina. It is expected to have a greater refractive effect when the device is located at a lower depth (ie about 1/3 to 1/2 of corneal depth) within the corneal matrix. The closer the device is to the periphery of the cornea, the smaller the refraction effect. Devices located closer to the central cornea can potentially correct myopia to less than 20 diopters. Intraoperative corneal or automated corneal system may be helpful. However, in surgery involving the cornea, intraoperative curvature measurements do not appear to be reproducible as expected.

The device is implanted into a circular lamellar channel formed at corneal depth 1/2 to 2/3 by a circular dissection instrument requiring only a small retinal mid-corneal corneal incision. The knife is used to form about 2 mm radial incisions starting from 2.5 mm to 3.5 mm from the center of the cornea. The surface of the cornea is cut only in the incision. Suarez nebulizers are introduced into the base of the incision and small lamellar channels are formed. Application of the vacuum concentrator guide is used to fix the pupil and the 8-9 mm outer diameter lamella channeling tool introduced through the incision into the lamella channel is rotated to rotate the 360 degree channel around the corneal retina at corneal depth 1/2 to 2/3. To form. After removing the channeling tool, the circular endoscopy tweezers are inserted into the same channel and rotated 360 degrees so that the tweezers tip emerges from the radial incision. One end of the device is inserted into the tweezers and thus the closed tweezers stir holds the device and the circular tweezers rotate until the device is progressively pulled locally. The device is also pulled locally using a circular instrument with a hook at the end. When using a circular hook mechanism it is first inserted into the lamellas in the opposite direction of the insertion direction to the loop. The hook is then attached to a preformed loop or hole on the leading end of the adjustable corneal device and the circular hook mechanism rotates backwards and is slowly removed to progressively pull the ring locally. The top and bottom of the device can be brought together and secured to each other by suture or tight contact.

In summary, the adjustment or selection of factors affecting device size, shape, width, shell thickness and circumference, corneal curvature and refraction results occurs in three distinct phases.

1. Prior to surgery, the presence or absence of the above-described variables and supporting skeletons are selected using a calculation chart developed from retrospective studies as a selection guide for each variable.

2. During surgery, the strength of the device is adjusted as necessary by the use of the cornea during surgery. The ring that passes completely around the implant is firm and connected at various tensile forces,

a. Control of the implant volume possibly leads to more predictable changes in corneal curvature than attempts to control corneal curvature by application of tensile force or removal of tensile force.

b. Keep in mind that when primitive correction is required, circular radial force is required to maintain corneal curvature and at least one ring connected at the top and bottom of the device or at tensile force.

3. Postoperative Control. Simple and easily performed postoperative control that avoids the complexity of the occurrence of reoperation by most corneal refraction methods is made feasible by the above mechanism of control. The postoperative adjustment may include improper preoperative implant selection, corneal hydration during surgery where different corneal curvature is induced after the corneal hydration state changes postoperatively, an unexpected or changing wound treatment response around the implant, and an unknown Compensation for later refractive changes caused by the element can be compensated. The postoperative control is made by a flexible corneal device containing multiple rings that can be easily removed to change the volume of the device and increase corneal curvature.

The cornea is cut on an area with any point in front of the ring, preferably a portion of the anterior bark with the bark removed, to allow easier access to the ring. The strand can also be removed from the initial incision. If the ring is removed from a portion other than the top or bottom of the device, the top and bottom are closed such that strand removal causes partial vacuum formation to facilitate ring collapse. Ring removal from the device minimally interferes with the substrate-graft contact surface as compared to removing the device itself, thus minimizing the effects wound healing and edema will have on control. The postoperative control is believed to be an additional step in any method that attempts to meet the criteria for an ideal corneal-refractive method. If the refractive results are not ideal, the following steps can be taken.

a. 12A and 12B, the corneal curvature 49 is cut when the corneal curvature is too sharp and the patient is myopia, and when there is a ring connected to the tension force 38, which is cut off to relieve some of the contraction source of force. Flatten Ideally the ring is cut close to the initial incision. The rings can be cut with a sharp needle, knife or laser. If still inadequate one or more rings may be cut. The two ends of the device do not fluctuate even when all the rings are cut. If the ring cut is too flat, one ring can be completely removed from the device and the eye to relatively reduce the volume of the device where the corneal curvature is incidentally sharpened. In rare cases where the ring is difficult to remove, the ring may be cut at 180 degrees and then each half removed by an initial incision. Corneal curvature can be reduced by another method. Rings or other solid biocompatible materials in the device are attached to larger diameters so that rings in the device are removed, and larger rings are locally drawn progressively to increase the volume of the device and flatten the anterior corneal curvature.

b. If the corneal curvature is too flat after surgery as shown in FIGS. 13A and 13B (FIG. 13A), the ring with little or no tensile force is cut and removed, as shown in FIG. 13B with myopic movement as described above. Incline the corneal curvature. This is because one or more rings do not contribute to circular radiation on the cornea. Overcalibration to the control, and if excessively inclined due to the removal of the ring, the tensioned ring is cut and left in the local, so that the cornea can be flattened or a larger new ring can be localized.

A conventional adjusting device 30 of the invention is shown in FIG. 14A. The outer diameter is about 0.9 mm, the total thickness is about 0.3 mm, the larger inner width is about 0.80 mm and the minor diameter is about 0.20 mm. Devices of this size are expected to calibrate about 3 diopters of myopia. The following is assumed to calculate the number of rings that are comfortably fixed and the diopter change due to each ring removal. The cross-sectional area of the ovoid device is about 0.11 mm 2. Since this volume cannot be completely filled with a ring having a round cross section, there is a space between the round rings and the area occupied by the rings is ideally 78.5%. About four (diameter 0.175 mm) rings 38b or seven (diameter 0.125 mm) rings 38a will fit in the space. Complete removal of all rings is flattened by 0.2 mm or diopter change 2.0. The average diopter change for each 0.175 diameter ring removed from the conventional embodiment is 0.5 diopters, and the diopter change for 0.125 mm diameter rings is 0.3 diopters. For patients with early myopia, the result can go beyond the initial refractive index by 50% and the primitive can still be manipulated by the ring removal itself. Hypertreatment causing hyperopia is a major drawback for most corneal refraction methods. In radial keratotomy, the wound healing process occurs over many years and often becomes progressive hyperopia. Patients who become symptomatic primitive after surgery will be very unhappy. Therefore, most surgeons use a calculation chart to achieve some heat correction. In one study of photorefractive keratectomy, the main reason why a patient did not have a PRK-corrected secondary eye (if the primary eye was also corrected to PKR) was due to dissatisfaction due to hyperopia in the operated eye. It is known. The techniques described herein easily correct overcorrection primitives.

In a simple adjustment of the technique the device can be used to correct astigmatism. The rate of change of curvature in front of the cornea is the cause of most astigmatism. The light beams converge as one point on one or more planes and no main focus is formed. Astigmatism typically depends on the presence of toroids instead of the spherical curvature of the curable surface of the eye. To correct astigmatism, certain areas of the cornea must be corrected to a greater extent than other areas. The implant may vary in thickness along the circumference of the device with sections of the device having increased volume corresponding to areas of the cornea that have steep slopes and require greater correction. In FIG. 15A, the ring 32 completes about 360 degrees in the device. Another portion of the ring 33 is shorter and absent at about 4-6 o'clock in the figure. The ring 34 is a mirror image arrangement of 33 and is absent at the 6-8 o'clock direction. The ring 35 is folded twice in the region of increased thickness. The ring 36 is a mirror image arrangement of 35. The end of the ring 37 is attached to the device by glue or other means. The end 38 of the ring on the other side is similarly fixed. As shown by the larger volume of the cross section of the implant in FIG. 15B, the area with more rings, when compared to the size of the cross section of FIG. 15C, performs the parallax correction necessary for astigmatism with an increased volume of 50% or less. If the astigmatism is overcorrected, the rings 35 and 36 may be pulled until the loop 31 is removed and then cut at the point at which the rings emerge from the device. Removal of loop 31 reduces the ratio of larger areas to smaller areas of the implant by 6/3 to 4/3. The ring 32 can be completely removed when the astigmatism is heat corrected, increasing the ratio from 6/3 to 5/2. Many different variations of the subject matter are possible and some examples are shown in FIGS. 16A, 16B and 16C. Rings 38a to 38c as shown in Fig. 16 (a), rings 38d to 38g as shown in Fig. 16b and rings 38h to 38k as shown in Fig. 16c are number, length, diameter , The presence of one or more loops at the ends of the rings, and whether the rings are secured to the device. Deformation can occur in flexible devices that can have a support backing of PMMA or other polymeric materials. The thickness of the device shell can also vary. Place the top and bottom of the implant locally and secure. Ring control is based on the principles described above. Manipulation of the ring is typically by the initial incision site, but the device has a small circle removed from the anterior shell so that a small hole located 180 degrees from the original incision site where the ring can be adjusted or removed as shown in FIG. 90). The ring need not be 360 degrees in length as shown in FIGS. 15 and 16 and may also be cut in the middle of the length to facilitate its removal in the future.

In another embodiment, the device is increased in thickness by being inserted into the co-implant shell 30a and formed by the presence of a thicker partial ring 71 that may comprise the same material as the implant wall or a rigid material such as PMMA. May have an area of (FIG. 17). The thicker ring 71 may have a variety of cross-sectional shapes, preferably corresponding to the cross section of the device and one or more partial rings 71 may be provided. It may be 10 to 360 degrees in chord length. The end 71a of the partial ring is gradually tapered so that the ring end thickness becomes the thinnest area of the device. The thickness of the partial ring may vary and the thick section 75 of the device may be a multiple of the thickness of the thinnest section 76 of the device. There is a partial ring 71 of similar thickness, which may be similar in length and thickness but 120 to 180 degrees away from the opposite side of the device. The two partial rings are connected to each other by strand S as shown in FIG. 17A. The astigmatism axis can later be adjusted through the initial incision site by pulling the ring in one direction or the other, thus changing the position of the partial ring relative to its direction from the central axis of the device within the device chamber. The individual partial rings may have rings that connect one end to the other so that each partial ring can be adjusted independently. As described above, many different variations are possible with respect to the subject matter. Such specific sub-embodiments can be used in any of the methods described above. An important advantage of the design is the reversibility of the method. The method may be fully reversible by surgical removal of the device or the refractive effect may be partially altered as described above. The mediation itself can also be reversible.

In another useful embodiment, the outer shell of the implantable device includes a biocompatible porous polymeric material, such as a microporous polypropylene tube, or a material used in dialysis tubing and membrane filters. The properties of the porous shell are similar to those described above, which include sufficient flexibility to reduce the thickness of the device when the biocompatible filler material is removed. The advantage of the porous shell is to include increased nutrient diffusion to the anterior corneal matrix.

Another method of increased nutrient diffusion to the anterior corneal stroma is to place an opening in the shell of the implant. The openings can be multiple and can be oriented radially or longitudinally of varying lengths and widths and placed on the front or back of the device.

In accordance with an alternative embodiment of the present invention, the implant forms a fence to accommodate filler such as saline that can be easily removed. The biocompatible fluid filler is preferably conventional saline or sterile water, but any other biocompatible and acceptable fillers such as hyaluronic acid, hydrogel solution or dextran are equally acceptable as liquid fillers. The implant has one or more compartments as shown in FIGS. 18 and 19, each of which is waterproof and individual. Each compartment is filled with a biocompatible fluid. The compartment may extend along the length of the ring or only partially extend along the length of the ring. The cross section of the ring may be of various geometric shapes such as circular, oval, rectangular, square or triangular. The cross sectional diameter of each compartment can vary along its length.

The implant 106 includes a tubular shell 107 made of an elastic material, such as silicone, acrylic or urethane polymer. The shell material has adequate stiffness to generally maintain a circular shape in the top view when sufficiently filled, and also increase the thickness when filling the chamber 117 with fluid as shown in FIGS. 20A and 20B individually, 117 has a suitable elasticity that flattens out when removing the filler material. The shell of the device should generally have sufficient structural integrity, strength, elasticity and extension in order to maintain and expand its circular shape. The composition material thereof may be similar to that used to make eyepieces that can be folded or modified, such as silicone polymers, urethane polymers, acrylic polymers, or materials used in soft contact lenses. If the compartment is removed from the ring, the compartment wall should have similar material properties as described for the entire ring wall.

In FIG. 7B, the cross-section 106 of the implant taken radially through the center of the implant will be an elliptical shape similar to the implant 30 shown in FIG. 7B. The different embodiments shown in FIG. 24 are each adapted to control the composition material of the implant wall, the implant connection mode, the type of biocompatible filler material and the cross-sectional parameters of the implant, for example round, square, rectangular, triangular, oval Many sub-embodiments can be provided by changing parameters such as implant formation from the cross section in the form of the back. The major axis 39 of the cross section of the implant, which is analogous to the implant 106 of this embodiment, forms a cone curve corresponding to the slope of the corneal arch of the anterior pole of the cornea. The angle is about 20 to 25 degrees. As shown in FIG. 7A, the two ends of the degradation implant 106 may be parallel to one another as compared to the two ends 45, 46 of the degradation implant 30 and in a method such as suture or close contact. The ends coincide so that they can be fixedly fixed during surgery.

The device is adjusted to be implanted into the surrounding stromal cornea. When implanted, the thickness and geometry are adjusted to change the central corneal curvature without invading the central visual area of the cornea, reducing the spread of nutrients in the central cornea. It is sized to include an elastic material that can be easily inserted into the surrounding human corneal stroma and is biocompatible and more specifically compatible with eye tissue. This includes varying thicknesses and columnar co- implants such that the central viewing area is flattened by removing fluid from the selection compartment. The dimensions of the implant 106 have a maximum thickness (after full increase) of about 0.1 to 0.8 mm, a width of about 0.4 to 2.0 mm, and an outer total diameter of about 4 to 12 mm. The thickness of the shell 107 of the implant 106 may vary as shown in part of FIG. 24.

The implant may contain one or several chambers, each of which is waterproof and is distinguished from other compartments. The compartments are each waterproof, but the compartment wall may or may not be an integral part of the outer wall of the ring. When the compartment wall is separated from the shell wall as shown in FIG. 22, not only does it remove fluid from the compartment to reduce the total ring thickness, but also the compartment itself from the loop to reduce the total ring volume as shown in FIGS. 22A-22C. It has the added advantage of reducing. In FIG. 22C, the ring thickness 122 is smaller than the ring thickness 121 of FIG. 22B and has a smaller thickness than the ring of FIG. 22A. Thus each compartment is a separate unit. Regulation is carried out with rings implanted in the cornea. There may be several compartments distinguished from the outer wall present in the lumen defined by the shell of the ring. The compartments can vary in size and shape and can be extended 360 degrees, although not necessary, especially in situations where parallax ring thickness is required, such as astigmatism.

In another embodiment presenting a possible variant of the implant with outer wall and inner compartment, the outer wall of the ring may contain beads 125 containing a plurality of individual microcapsules or a closed volume 126 of fluid as shown in FIG. 23. Include. Each small volume is sealed by a thin membrane and delimited and filled with a biocompatible liquid. The outer wall has openings 127 and 128 and provides fluidic interaction between the outside of the ring and the lumen 129 containing the microcapsules. Each microcapsule is individually punctured with a sharp instrument or laser so that fluid flows out of the capsule through the outer wall opening and is absorbed by the corneal tissue. This reduces ring thickness, sharpens the curvature of the cornea and fine tunes the refraction results. Biocompatible materials can be removed from the ring, but the advantage is that the material is not removed directly from the ring outside the cornea. The technique satisfies the need to provide an opportunity to modify corneal curvature by minimizing surgical intervention and arbitrarily adjusting the volume of the implant. The use of microcapsules is well known in the pharmaceutical art. It is also well known that fluid injection into the healthy cornea is rapidly reabsorbed. Fluid injection of the cornea into the matrix is the following cataract surgery that is commonly performed to facilitate corneal wound self sealing.

If the compartment wall is distinguished from the outer wall as shown in FIG. 22, the outer wall may comprise a biocompatible porous material as used in hemodialysis tubes. The properties of the porous shell are similar to those described above, which are flexible enough to reduce the thickness of the device when the biocompatible filler material is removed. An advantage of the porous shell is improved nutrient diffusion into the anterior corneal matrix. Another way to improve nutrient spread to the anterior corneal stroma is to place an opening 128 or fluency in the shell of the implant. The openings are multiple and can be oriented radially or longitudinally in length and width and located on the front or back of the device.

Embodiments in which the refractive error varies in shape, size, circumference, strand size, type of biocompatible filler material, and the number of compartments present. The elastic shell 107 may also vary as shown by the embodiment of the implant illustrated in FIGS. 24 (a) -24 (d). The choice is as follows.

1. Absence of Supported Polymethylmethacrylate (PMMA).

2. PMMA or other rigid physiologically acceptable polymer backbone that strengthens the inner circumference of the device wall as shown in FIG. 24C. As shown in FIG. 24C, the thickened area 132 may be increased in thickness of the flexible composition comprising the wall or it may be the rigid polymer backbone described above.

3. PMMA or other rigid polymer backbone that strengthens the outer circumference of the implant wall as shown in FIG. 21B.

4. Supports for inner and outer circumferences.

5. Compartment rings used in combination with the presence of other biocompatible solid filler materials that may also be removed. Compartment 135 in FIG. 24E contains a fluid and the same ring also contains solid stranded filaments 125 that may be removed.

The size of the device selected should be such that the range of secondary overcorrection or thermal correction for the individual variability of the response to surgery is easily corrected by the method described above. The maximum thickness, circumference, and type of support skeleton is selected prior to insertion of the implant. An ideal embodiment in which preoperative refractive states and other relevant data are provided is selected prior to surgery, whereby the embodiment is further adjusted to the extent necessary to determine abnormal curvature. The device is inserted into the peripheral cornea at an appropriate depth and then further adjusted to more precisely control the shape of the cornea and to focus the light entering the eye on the retina. Keratoscopy or automatic corneal system during surgery may be helpful. However, in surgery involving the cornea, intraoperative curvature measurements do not appear to be reproducible as expected.

The device is implanted into a circular lamellar channel formed at corneal depth 1/2 to 2/3 by a circular dissection instrument requiring a small midretinal corneal incision. The knife is used to form about 2 mm radial incisions starting from 2.5 mm to 3.5 mm from the center of the cornea. The surface of the cornea is cut only in this incision. Suarez nebulizers are introduced into the base of the incision and small lamellar channels are formed. Application of the vacuum concentrator guide is used to fix the pupil and the 8-9 mm outer diameter lamella channeling tool introduced through the incision into the lamella channel is rotated to rotate the 360 degree channel around the corneal retina at corneal depth 1/2 to 2/3. To form. After removing the channeling tool, the circular endoscopy tweezers are inserted into the same channel and rotated 360 degrees so that the tweezers tip emerges from the radial incision. One end of the device is inserted into the tweezers and thus the closed tweezers stir holds the device and the circular tweezers rotate until the device is progressively pulled locally. Circular hook mechanisms or other similar mechanisms as described above may be used to mount the instrument. The top and bottom of the device can be brought together and secured to each other by suture or tight contact.

In summary, the adjustment or selection of factors affecting implant size, shape, width, shell thickness and circumference, corneal curvature and refraction results occurs in three distinct phases.

1. Prior to surgery, the presence or absence of the above-described variables and supporting skeletons are selected using a calculation chart developed from retrospective studies as a guide to the selection of each variable.

2. During surgery, the strength of the device is adjusted as necessary by the use of the cornea during surgery.

3. Postoperative Control. Simple and easily performed post-operative control that avoids the complexity of re-surgical occurrence by most corneal refraction methods is made viable by this mechanism of control. The postoperative control may include inadequate preoperative implant selection, corneal hydration during surgery where different corneal curvature is induced after the corneal hydration state changes postoperatively, an unexpected or changing wound treatment response around the implant, and an unknown It is possible to compensate for the later refractive change caused by the factor. The postoperative control may be performed by an elastic corneal implant containing multiple compartments filled with fluid and distinct from other compartments, wherein one or more compartments from which fluid may be removed reduce the thickness of the implant and reduce corneal curvature. Increase. The removal of fluid by selective compartment penetration minimizes the effect the wound treatment and edema can have on control, with minimal disruption of the substrate-graft contact surface as compared to removing the implant itself. The postoperative control is believed to be an essential additional step in any method that attempts to meet the criteria for an ideal corneal refraction method. If the refractive results are not ideal, the following steps can be taken.

a. Corneal curvature can be flattened by the following method. Strands of biocompatible material in the implant can be attached to larger diameter strands to remove the strands in the implant, with the larger strands being pulled progressively locally to thicken the implant and flatten the anterior corneal curvature. do.

b. If the corneal curvature 136 is too flat after surgery (FIG. 25A) as shown in FIGS. 25A and 25B, the ring thickness may be reduced by selectively penetrating the compartment 160 for draining the fluid or the fluid may be injected into the syringe and needle. Can be removed by The compartment 160 may be broken to cause a greater corneal curvature 137. Since the other chambers are distinctive and do not leak, there is no need to repair the penetration site. One or more compartments may be penetrated as needed. When correcting myopia, primordial results are difficult to correct by any recent corneal refraction method and overcorrection of myopia occurs. By selectively penetrating one or more compartments by the device, fluid is removed to make the raw result relatively easily reversible. Simple shrinkage of the rings by fluid removal from one or more compartments reduces the ring thickness in a definite increment and fine tunes the refraction results. Controlled removal of fluid from the ported ring is technically difficult due to the very small volume of fluid. This final problem requires additional sophistication. Similar fluid filling rings are described in US Pat. No. 5,466,260 to Silvestirini. An expandable ring is described that can be expanded with brine by injecting fluid into the ring, preferably through a nozzle, which is a one-way valve. The possibility of fluid discharge is also described by inserting a hypodermic needle into the valve opening or by draining fluid from within the annulus. However, after implantation of the ring into the cornea, the nozzle is no longer accessible.

Multi-chamber fluid filling rings overcome various problems associated with the Sylvestini ring. The manufacture of valves that act as fine nozzles or one-way valves is extremely difficult. Outflow or loss of fluid through nozzles or valves over long periods of time is a major drawback because the thickness of the ring decreases with the change in the deflection result of fluid loss from the ring. There are also major technical difficulties in inducing a hypodermic needle into the port or maintaining this position when the fluid is ejected. The thickness of the ring is typically 0.3 mm. If the needle is to be introduced into the port, the front part of the ring essentially causes shrinkage in the area, reducing the thickness to less than 0.2 mm. The more watertight nozzles are sealed, the greater will be the resistance to needles penetrating through the ports, which will increase incidental shrinkage, decrease ring thickness and increase the risk of penetration of the ring wall just below the nozzle. In addition, a significant amount of fluid outflow during penetrating the nozzle with a hypodermic needle for injecting or removing fluid may make it difficult to remove the fluid correctly. In addition, the amount that needs to be removed to perform the refractive change 0.25 to 0.50 diopters is extremely small. A typical amount that needs to be removed to effect this change is about 0.002 milliliters and leaves no room for error.

In contrast, each individual unit, a multi-chamber fluid filling ring, does not require a port that allows for the complexity of long term outflow. The difficulty of spilling the correct amount of fluid is also overcome by penetrating a selective compartment containing a distinct amount of fluid absorbed by the corneal tissue. Since each unit is distinctive and waterproof, there is no need to seal the through area. Needless to say, the fluid cannot be injected after the ring is manufactured and each chamber is sealed.

A conventionally adjustable implant 106 of the present invention is shown in FIG. The width 150 of the outer diameter is 0.85 mm, the total thickness 151 is 0.3 mm, the maximum inner diameter 152 is 0.75 mm, and the minor diameter 153 is 0.20 mm. Implants of this size are expected to correct myopia with a diopter of about 3.0. Assuming three compartments exist, fluid removal from all three compartments flattens the ring 0.15 mm or changes the corneal curvature by 1.5 diopters. The average diopter change in fluid removal from each compartment is about 0.5 diopters. For early myopia patients, the result can be over 50% of initial refractive index and hyperopia can still be manipulated with fluid removal only.

Hypertreatment causing hyperopia is a major drawback for most corneal refraction methods. In radiokeratotomy, the wound healing process occurs over the years and often becomes progressive hyperopia. Patients who become symptomatic primitive after surgery will be very unhappy. Therefore, most surgeons use a calculation chart to achieve some heat correction.

In one study of photorefractive keratectomy, the main reason why a patient did not have a PRK-corrected secondary eye (if the primary eye was also corrected to PKR) was due to dissatisfaction due to hyperopia in the operated eye. It is known. The technique easily facilitates post-operative correction of overcorrected hyperopia.

In simple operation of the adjustable implantation technique, the device can be used to correct astigmatism. The rate of change of curvature in front of the cornea is the cause of most astigmatism. Rays converge as one point in one or more planes and one main focal point is not formed. Astigmatism typically depends on the presence of toroids instead of the spherical curvature of the refractory surface of the eye. To correct astigmatism, it is clear that certain areas of the cornea must be corrected to a greater extent than the blister area. As shown in FIG. 26, it may be placed in an implant specific size and shape chamber that increases dimensions in the appropriate area of the ring as compared to other areas. The cross-section shown in FIG. 26B, which is a solid section of the implant, will have a fixed thickness 138. Implant sections with increased thickness 139 correspond to areas of the cornea that require greater correction. Instead of changing the size and shape of the chamber, the annular wall may have a parallax thickness 140. Combinations of differential wall thicknesses and variable chamber sizes can also be used. Combinations of fluid chambers and solid phase biocompatible filler materials may also be used. Selective penetration of such chambers alters astigmatism correction results. Deformation in the number, length, diameter, volume and cross-sectional shape of each compartment can occur. Deformation may occur in elastic implants that may have a support backing of PMMA or other polymeric materials.

Therefore, it should be appreciated that the use of the present invention avoids the disadvantages of conventional refractive surgery methods, e.g. 1) progressive hyperopia due to radiokeratotomy. Hyperopia in any refraction method is generally a bad result because the patient does not have a clear field of view in any range and the hyperopia is harder to correct. The described method is particularly useful for complications such as 2) irreversibility of radiological incisions and laser excisional surgery as a result of primitive refraction; Necessity for chronic use of steroid drop, 5) laser ablation method, especially regression following reoperation, 6) reduction of positive spherical surface due to RK and laser ablation, which can lead to increased burn aberration, Invasion of keratomileusis, 8) lack of accuracy and predictability in all modern methods, and (9) corneal in the prior art, which can lead to variability in the effect and also shear of pericorneal channel lamellae associated with scar formation. Particularly suitable for controlling the possible need for repeated eating out and transplantation of the inner ring (ICR).

The last method for adjusting the implanted ring thickness is described in the prior art. These methods are discussed for controlling ring thickness during implantation and not after surgery. Attempts to adjust ring thickness are useful after corneal curvature essentially stabilizes. Adjustment of the device described in the prior art necessitates rotation of the ring with the resulting shear of the corneal ring contact surface. One example is the rotation of the rings, which somewhat overlaps the individual ring portions to increase or decrease the ring thickness. The shear of corneal tissue proximal to the ring can alter corneal curvature in an unpredictable manner and can cause scarring with unpredictable refractive long-term effects. In the embodiments described herein the ring thickness is controlled with minimal disturbance to surrounding tissue. Due to the nature of regulation, there is no rotational movement of one surface of the ring in contact with the corneal tissue with respect to the cornea. Clearly referring to “rotational motion” refers to the rotation of a ring similar to that required to initially insert the ring into the lamellae channel. Rotating movement of the implanted ring damages the corneal ring contact surface. In the embodiments described herein the corneal ring contact surface is not essentially damaged. There will be some movement of surrounding tissue with a decrease in ring thickness. In conclusion, the slight reduction in ring thickness by the described adjustments is not only much easier to perform but also has a much more predictable effect.

Dr. R. R. Eiferman, in the Journal of Refractive and Corneal Surgery, “can control the amount of tissue added to or reduced in the cornea and can optimize refractive surgery if the biological response can be controlled. It described. An ideal way to modulate a biological response is to minimally interfere with corneal tissue and to minimize the wound healing response.

Dr. K. K. Thompson asks the same document, "Is it possible for refractive surgery techniques to overlook all the variability effects of corneal wound treatment?" This is not the case with any initial corneal refraction method, but the variability effect of corneal wound treatment can be avoided by minimizing the impairment of corneal tissue with the adjustable device of the present invention.

Most refractive surgery methods use a calculation chart to calculate the corrections needed, but cannot fully account for the individual variable response to refractive surgery. Often, all unpredictable improvement methods rely on correcting residual refractive errors, which inevitably increases complication rates and response formation. The individual masonry response to the correction calculated by the various embodiments of the device is not completely predictable and allows for easy control after surgery, more importantly after corneal hydration, and the wound healing response removes simple loops from the device. Or ring substitution, or selective compartment penetration. The nature of this control minimizes the implant-corneal contact (different from eating out of the ICR), which results in a much more predictable effect than the implantation of the implant itself, which induces fewer wound healing responses than recent methods such as RK and PRK. Foresee it. In addition, when correcting myopia, the raw results are very difficult to correct with recent corneal refraction methods and overcorrection of myopia occurs. In accordance with a preferred embodiment of the present invention the raw result is relatively easily reversible by suture removal. Typically, in most corneal refraction methods for myopia, the surgeon aims for some heat correction to avoid primitive outcomes. The ease with which primitive outcomes are controlled by the implants of the present invention allows the surgeon to achieve the full benefit of the calculation chart with the goal of complete calibration so that a greater percentage of patients have the desired refractive results without the implant's adjustment. The surgeon may choose to adjust after some overcorrection.

Individual responses to any corneal refractive surgery method are variable and "perfect" calculations do not produce reliable and predictable results for specific individuals, and a simple, safe and effective technique for corneal curvature control is desirable and desirable. It is assumed that the regulation can predict the impact with minimal disturbance to surrounding tissue. The control should also be easily achieved after implantation and after surgery after the factors affecting corneal curvature are stabilized. In various embodiments, the implant may advantageously be easily adjusted in thickness by simply removing the individual amount of biocompatible filler material from the implanted device during implantation and, more importantly, in many subsequent cases, to provide refractive results. Fine tune

In conclusion, initial inaccuracy correction, inadequate adjustment or removal of the final strand in the correction refractive error by the adjustable implantation technique according to the preferred embodiment is also easily treated by removing the implant itself or leaving it locally. Even if this is achieved, other refractive methods, such as laser ablation surgery, are contemplated.

It is also to be understood that the above description of various embodiments of the invention is for purposes of illustration and is not intended to limit the invention to the precise form of the implements and manners described herein. Accordingly, changes may be made by those skilled in the art without departing from the spirit of the invention as set forth in the claims below.

Claims (41)

A tubular member made of a biocompatible material forming a ring; And Strand in the cavity of the tubular member, at least partially extending along the length of the tubular member Corneal ring (corneal ring) comprising. The corneal yun of claim 1, further comprising at least one other strand. The corneal lubrication of claim 1, wherein the tubular member is made of a flexible material. The corneal lubrication of claim 1, wherein the strands are made of a material selected from the group consisting of polymethylmethacrylate, nylon, merylene, and polypropylene. 2. The corneal yun of claim 1, wherein the tubular member comprises a reinforcing backbone along at least a portion of its length. The corneal lubrication of claim 1, wherein the tubular member is porous. 2. The corneal lubrication of claim 1, wherein the tubular member comprises a plurality of openings for fluid exchange between the cavity and the exterior of the tubular member. 2. The corneal Yun of claim 1, wherein the tubular member includes an opening for providing access to the cavity. 2. The corneal yun of claim 1, wherein the length of the strands is approximately equal to the length of the tubular member. 2. The corneal yun of claim 1, wherein the strands have at least one thicker portion. The corneal lubrication of claim 1, wherein the strands are folded in the tubular member. 2. The corneal yun of claim 1, wherein the circumference of the cross-sectional area of the strand is angled. The corneal yun of claim 1, wherein the circumference of the cross-sectional area of the strand is curved. The corneal yun of claim 1, wherein the strand comprises a marker at at least one end. 2. The corneal yun of claim 1, wherein the thickness of the strand is adjustable and the strand comprises a pair of complementary separating rings. 2. The corneal yun of claim 1, wherein the strands comprise means for catching them. 17. The corneal yun of claim 16, wherein the retaining means consists of a loop at at least one end of the strand. Making a radial incision in the cornea; Forming an annular channel extending between the lamellae of the corneal tissue near the visual area of the cornea at the incision; Inserting into the incision an end of the coronary limbus containing the solid filler material in the interior cavity; And Gradually moving the corneal lubrication near the annular channel until it is fully inserted Method for adjusting the corneal curvature of the eye comprising a. 19. The method of claim 18, wherein the solid filler material comprises at least one strand of material extending along at least a portion of the corneal lip. 20. The method of claim 19, further comprising adjusting the radial cross-sectional area of the corneal limbus. 20. The method of claim 19, further comprising adjusting the thickness of at least a portion of the limbal cornea. The method of claim 21, wherein the step of adjusting comprises removing at least one of the at least one strand. The method of claim 21, wherein the step of adjusting comprises replacing at least one of the at least one strand with a thicker strand. The method of claim 21, wherein the strand has a thick portion and the step of adjusting comprises moving the strand so that the thick portion instead enters the corneal limbus. The method of claim 21 wherein the thickness of the strand comprising a pair of complementary separating rings is adjustable. The method of claim 21, wherein the step of adjusting comprises: connecting at least one of the at least one strand the first and second ends of the strand to form a strand ring; And tensioning the strand ring. The method of claim 26, wherein the adjusting step comprises cutting the stretched strand ring. The method of claim 21, wherein the adjusting step comprises: connecting the first end and the second end of the tubular member in the tubular member to form a tubular ring; And tensioning the tubular ring. Making a radial incision in the cornea in the first surgery; Forming an annular channel extending between the lamellae of the cornea near the visual area of the cornea at the incision; Inserting the end of the coronary limbus into the incision comprising at least one strand of solid material in the inner tubular cavity; Gradually moving the corneal lubrication near the annular channel until it is fully inserted; And Adjusting the thickness of the corneal limbus by moving at least one strand in a second surgery Corneal curvature adjustment method of the eye comprising a. The method of claim 29, further comprising adjusting the thickness of at least a portion of the corneal limbus in the first surgery. 32. The method of claim 30, wherein the step of adjusting comprises removing at least one of the strands. The method of claim 30, wherein the step of adjusting comprises replacing one of the strands with a thicker strand. Biocompatible materials; And A plurality of internal cavities each filled with a fluid extending along at least a portion of the length of the tubular member Corneal yun comprising a tubular member comprising a ring forming. 34. The corneal yun of claim 33, wherein the fluid of at least one of the cavities consists of saline solution. 34. The corneal lubrication of claim 33, wherein the fluid of at least one of the cavities consists of a gel. Making a radial incision in the cornea; Forming an annular channel extending between the lamellae of the corneal tissue near the visual area of the cornea at the incision; Inserting the end of the coronary limbus into the incision comprising a plurality of compartments filled with fluid; And Progressively moving the corneal lubrication near the annular channel until it is fully inserted Containing, corneal curvature adjustment method of the eye. 37. The method of claim 36, wherein at least one of the compartments is separated from the tubular member. 37. The method of claim 36, further comprising adjusting the radial cross-sectional area of at least a portion of the corneal limbus. The method of claim 38, wherein the step of adjusting comprises removing at least some fluid from at least one of the compartments. 37. The method of claim 36, further comprising adjusting the thickness of at least a portion of the corneal limbus. Adjusting the thickness of the corneal limbus by removing fluid from at least one of the compartments in the second surgery.