HK1031319B - Interactive corrective eye surgery system with topography and laser system interface - Google Patents

Description

Interactive corrective eye surgery system using a topographical and laser system interface

Technical Field

The present invention relates to a system and a method for correcting corneal irregularities by reshaping the cornea of an eye to achieve a desired corrected corneal curvature. Preferred embodiments of the present invention include a topography apparatus for detailed mapping of corneal irregularities and surface deviations; and an interface system for receiving and processing topographical data and providing directions for a laser system or the like to perform a predetermined contour cut on a substrate such as a corneal laminate, and also to provide a variety of real and simulated pre-and post-operative visual sensations. The interface system provides a surgeon or the like with a tool that allows the surgeon to estimate and simulate a variety of possible, alternative surgical procedures for a variety of corneal disorders, including irregular eyeball shapes and irregular corneal surfaces.

Background

For many years, humans have sought ways to correct vision problems. This can be seen in the development of contact lenses, which are initially hard lenses, to later soft and disposable soft lenses. While these optical aids can make them clearly visible to the patient when they are worn, they do not permanently cure vision disorders or diseases; also, in some cases, for example, localized, highly irregular shaped corneal diseases, even lenses and contact lenses do not achieve a complete correction.

Approximately twenty years ago, surgical techniques for permanently correcting myopia and astigmatism were proposed as an achievement. The radial keratotomy procedure is to cut a notch in the anterior surface of the cornea or "window of the eye" with a diamond scalpel. Although this technique works relatively well, it still suffers from long-term visual stability problems and often 95% corneal clouding as a sequela to the wound, which can weaken the corneal function.

More recently, these older techniques have been replaced by laser treatment techniques that replaced a scalpel with a computer-controlled laser to gradually and repeatedly sculpt the shape of the cornea without cutting or weakening the vision, in most applications. These laser techniques are typically realized by a light absorption process using an excimer laser.

Excimer lasers are used primarily in the manufacture of computer microchips for etching circuit boards. However, extreme accuracy of the laserAnd low thermal influence makes it well suited as a laser for treating the eye. That is, many lasers used to treat the eye are extremely accurate and only 0.25 microns (1/4000) per pulse^thMm) cells were removed. In repeated engravings, the excimer laser gently "vaporizes" or causes the cells to vaporize; there is no burning or cutting. In most cases, laser treatment takes only 20 to 45 seconds, depending on the severity of the refractive error. The importance of a fast treatment time is that for some procedures, an excessively prolonged treatment time may slow down the post-operative healing process, thereby reducing the resulting level of vision.

For a normal eye, the light rays entering the eye are accurately focused on the retina and form a sharp image. The natural lens in the eye adjusts well for most of the light that is bent or focused at the cornea. If the light is not focused on the retina, it is said that the eye has refractive error. Typical refractive errors include: myopia, hyperopia, and astigmatism. Excimer lasers have been used as a success in correcting myopia, hyperopia and astigmatism by repeatedly sculpting the cornea so that the corneal curvature allows the light to be focused normally on the retina.

For myopia, the light is always focused in front of the retina, not behind the retina. This results in blurred vision, especially when looking at distant objects. Myopia is caused by an excessively long eyeball length or excessive corneal curvature.

For hyperopia, the rays are focused behind the retina. Resulting in blurred vision, especially when viewing close objects. Hyperopia is caused by either too short a length of the eye or too flat a cornea.

For astigmatism, the cornea, or "window of the eye," a shape with irregular curvature is more like a football rather than a soccer ball. The light rays are focused at different points. A person often has some degree of myopia and astigmatism, or hyperopia and astigmatism, simultaneously. Any surface profile irregularities can result in improper focusing of the eye, as the irregularities cause the light rays to deviate from the intended focus point on the retina.

In methods for laser correction of myopia, the cornea is made flatter to better focus the light normally on the retina; correcting hyperopia in contrast is to make the cornea more curved. For astigmatism, the surface of the cornea is repeatedly sculpted to have a regular curvature.

Presbyopia is a concern that results from the aging of the eye's natural lens and thus does not experience the same refractive errors as myopia, hyperopia and astigmatism mentioned above, although there is a possibility that presbyopia may occur with one or more of the refractive errors. Us patent No.5,533,997 to dr. luis. a. ruiz describes an apparatus and method for presbyopia correction, including a mode that has been shown by the inventors to be effective in removing cells from the eye with a laser system in presbyopia correction.

One prior art laser treatment method is known as image refractive keratectomy (PRK), in which a laser beam is directed at the corneal surface after a thin surface layer of epithelial cells has been removed (e.g., by wiping with a solvent, primary laser treatment, or less abrasion). After the laser directly repeatedly sculpts the cornea, leaving an exposed area of the cornea, it will take several days (e.g., 2 to 6 days) to heal and may be uncomfortable. The healing process sometimes results in regression (some refractive error may be recovered) or scarring (which may obscure vision), especially for patients with large refractive errors. While still being used in correcting low myopia and hyperopia, the PRK is often replaced for the same condition by LASIK procedures in which laser treatment is applied under the corneal protective flap. In the treatment of "Laser in situ Keratiomileussis" (LASIK), a thin flap of protective cornea like a trapdoor is lifted. The excimer laser treats the exposed anterior surface of the cornea. The end result is that the cornea is altered in a manner determined to allow normal focusing of light on the retina. At the end of the treatment, the protective flap is completely replaced. The LASIK technique leaves the original surface of the cornea virtually intact and, thus, free of bare areas that cause pain. In addition, the moderate healing process only has minimal decline, and the problems of scar and the like are avoided.

The profiling for the prior art PRK and LASIK laser treatments described above is based on mathematical equations and formulas that assume the eye as an ideal optical body or that the eye is a very regular sphere that follows a certain optical pattern. The prior art profiling does not take into account the fact that each eye is unique and has many individual and conventional small and large irregularities. Since prior art profiling is based on a fixed and regular cutting pattern, this can lead to situations where too many or too few cells are removed. For example, in a certain astigmatic condition, one side of it will have a greater condition than the diametrically opposite side. Thus, when the normal prior art profiling mode is applied to this condition (elliptical profiling), the cutting model will remove both the cells causing the condition and the cells not related to the condition, thus leading to the possibility of a new condition in the eye after treatment.

Likewise, the corneal surface is not a very smooth shell, and is large with small topographical irregularities. In prior laser systems, the formulas and patterns used to correct defects such as myopia, hyperopia and astigmatism do not take into account these surface irregularities. Thus, the end result of the profiling of the eye will deviate somewhat from the end result of the eye intended by the surgeon; and this is true for eyes with highly irregular surfaces, where defects are merely transferred to lower corneal heights and new defects are thereby created, which is generally not foreseeable in prior art systems. This is a fact: in previous PRK and LASIK treatments, the depth to which the laser ablated the eye was deeper at any concave region of the topography of the eye and shallower at any apex or convex region of the topography of the eye. In using the LASIK procedure, the use of a microkeratome to remove a thickness of the flap by pressing downward during the ablation or applanation process will double the topography of the outer surface of the cornea under the bare corneal stack.

Since prior art systems rely on rigid patterns and formulas built on standard optical models, these systems limit the surgeon's ability to fully function as a clinical expert in determining the profiling to be performed. In other words, these systems do not allow the surgeon to customize a copy cut that best suits the surgical clinical assessment required for patient correction.

The prior art systems are also not suitable for many vision correction cases that require detailed, or uniquely customized ablation, such as trauma, some congenital conditions, and conditions resulting from accidents during ophthalmic surgery.

The following documents, patents and patent applications, which are incorporated herein by reference, provide additional background information:

U.S. Pat. No.4,721,370 (L' Esperance); no.4,995,716(Wamicki et al); no.5,133,726(Ruiz et al); no.5,159,361(Cambier et al); no.5,318,046 (Rozakis); no.5,533,977(Ruiz et al); no.5,843,070(Cambier et al) and U.S. patent nos. 5,533,997 and 5,928,129 to Luis a. ruiz.

“Comeal Topography-The state of the Art”James P.Gill et.al.Published by SlackIncorporated.

Chapter 3.“Characterizing Astigmatism：Keratimetric Measurements Do NotAlways Accurately Reflect Comeal Topography”，25-33.

Chapter 5.Thomton，Spencer P.And Joseph Wakil.“The EyeSys 2000 CornealAnalysis System”55-75.

Chapter 7.Snook，Richard K，“Pachymetry and True Topography Using theORBSCAN System”89-103.

Chaper 9.Smolek，Micheal K.and Stephen D.Klyce.“The TomeyTechnology/Computed Anatomy TMS-1 Videokeratoscope.”123-48.

Chaper 16.Durrie S.，Donald R.Sanders，D.James Schumer，Manus C.Kraff，Robert T.Spector，and David Gubman.“Evaluating Excimer Laser Procedures”.241-61.

Ren，Qiushi，Richard H.Keates，Richard A.Hill，and Michael W.Berns.“LaserRefractive Surgery：A review and Current Status”.Optical Engineering， 34，642-59(1995).

Lin，J.T.“Critical Review on refractive Surgical Lasers”.Optical Engineering，34，668-75(1995).

Munnerlyn，Charles R.，Stephen J.Koons and John Marshall.“PhotorefractiveKeratectomy.A Technique for Laser Refractive Surgery”.J.Cataract Refract.Surg.14，46-52(Jan.1998).

Manns，Fabrice，Jui-Hui Shen，Per Soderberg，Takaaki Matsui，ans Jean-MarieParel.“Development of an Algorithm for Comeal Reshaping With a Scanning LaserBeam”.Applied Optics，34，4600-08(July 1995).

Disclosure of Invention

The present invention is directed to a system and method for ophthalmic surgery that allows a surgeon to use his surgical experience and knowledge of the patient to design a well-conditioned copy cut. The present invention thus provides the surgeon with a particularly versatile tool that opens the surgeon a wide range of surgical procedure options and thereby enables the surgeon to customize each procedure to perform the best clinical procedure for the patient in that situation. In providing a highly customized system, the present invention avoids limiting the surgeon to rigid contouring, which in some cases results in substantially only additional defects or failures for improving the patient's vision. In the present invention, the surgeon is able to direct the laser beam to create a particular laser model that can be seen as the most appropriate for removing the cells of the eye to achieve the best clinical results by the surgeon.

In addition, the present invention provides a highly accurate system that takes into account topographical irregularities in the corneal surface that vary from patient to patient when performing various corneal curvature corrections. By taking into account the individual's specific corneal topography, one is better able to avoid the possibility that irregularities in the corneal topography that deleteriously alter the desired surgical effect may remain in the post-operative state. Also, because the surgeon can eliminate topographical irregularities from patient to patient, more accurate and regular results for different patients are ensured.

The present invention also provides a method and apparatus for calibrating and patterning the operation of a laser beam in performing laser profiling, including the use of a substrate that presents different visual color cues to represent the extent to which the laser beam is going to arrive at the surface of the laser beam being performed, fed back to the laser control system.

The invention includes a topography device capable of providing data characteristic of the topography of a corneal surface. Preferably the topographical device is an elevational topographical device which provides data characteristics in the form of an elevational map for a topographical map of the patient's outer corneal contour, providing an accurate representation of the actual topography of the eye by a sufficient number of height point representations relative to the X-Y plane. The data characteristics for the elevation map are then output to the interface system of the present invention.

The interface system includes a topographer/interface input system that receives output data from the topographical device. The topographer/interface input system extracts data (e.g., x, y, z data) from the output data received by the topographer and stores the data, preferably in a matrix that is easily processed by the data processing system of the interface system.

The data processing system determines a suitable reference sphere that is an average or median sphere with respect to the vertices and valleys of the actual terrain (e.g., a sphere with the same volume of tissue, or vertices on the sphere and the same volume of non-tissue or valleys under the sphere). A suitable reference sphere may be formed using a variety of techniques, such as recursive spline splitting or Bezier curve techniques.

The interface system includes a graphical system coupled to the data processing system such that, based on the data output by the data processing system, the graphical system provides a plurality of graphical and interactive screens that enable the surgeon to calculate and customize the contour to achieve a particular profile that the surgeon considers to be the best cutting profile for a particular patient. With the combination of the data processing/graphical system of the present invention, the surgeon is able to see a variety of different cutting profiles as possible solutions, and to see a simulated post-operative situation for each hypothetical cutting profile.

The data processing system comprises a reference part or module and processes the data taking into account the correlation between the topographical profile determined by the topographical device and a suitable reference sphere, e.g. as previously determined, received by the interface system and the reference device. With the stored height data (e.g. a data matrix for all actual contours and suitable reference spheres), a graphical depiction of all actual topographical structures and suitable reference spheres in two and/or three dimensions along any one of a number of possible eye axes is provided. The appropriate reference sphere is represented as a line in the two-dimensional viewing window of the graphical system that is initially (when the middle appropriate reference sphere is selected as the initial reference) below the uppermost height of the terrain profile displayed in two dimensions. The two-dimensional display of the appropriate reference sphere can be used as a starting or reference point for the surgeon to begin calculating and viewing the different cutting profiles required to remove the cell from the topographical profile down to the appropriate reference sphere. The interface system provides means for varying the relative position of the appropriate reference sphere according to the actual topographical profile. The deviation between the two is best represented by varying the height of the straight line representing the appropriate reference sphere in a two-dimensional grid, while the two-dimensional profile description of the actual terrain profile (along the same axis) is fixed on the grid. Meanwhile, a plurality of screens show how the cut profile and the simulated postoperative eyeball profile are seen as each change in the reference line position (for example, a change in the altitude scale along diopters). The ablation profile and the resulting eye contour description are preferably both described in two-dimensional grid and three-dimensional description using three-dimensional description, preferably color topography, as the power deviation of the eye contour and the ablation profile across the corneal surface of the eye. So that the surgeon can determine the simulation results on the basis of the description and concentration of the complete completed eye contour and the cutting profile required to obtain this final contour, using a specific reference plane.

For example, the surgeon may lower the appropriate reference sphere relative to the actual topographic image of the eye, which description appears in the two-dimensional view as a reduction relative to a reference line of the two-dimensional topographic profile taken along the same, predetermined axis of the eye. If, for example, the surgeon lowers the reference line to a height corresponding to the lowest point of the topographical profile, the surgeon will be able to determine the maximum depth of cut required to make a correction to remove all topographical deviations at least along the axis of fixation. However, in special cases, such as where there is a local, very deep valley in the topography of the eyeball, too deep and/or too numerous ablations may be required, such as not as much corneal depth as could be done (post-operative corrective accidents occurring during early surgery). Thus, although the cutting profile is best suited to remove all irregularities in the topographical profile of the eyeball, the reference line set to coincide with the lowest topographical point on the surface of the eyeball may not be well suited for the patient. The observer can now use his surgical experience and knowledge of the patient to raise the reference line to a position representing the best clinical cutting profile in this case. For example, the surgeon may raise the reference line by a few diopters (e.g., up to 5 diopters) to remove a large proportion of the ocular irregularities on the reference sphere while avoiding any problems caused by over-cutting. The present invention allows the operator to easily make decisions when there may be potential problems. For example, a particular color may be assigned to any depth of cut that is going to go beyond a lower range point (e.g., 0.170mm deep), so that the view screen will provide an already identified warning of a potential problem. A separate pop-up window box with a question as to whether such an outline is desired or not may also be provided. It may also be the case that in order to select the height of the presumed best clinical sphere on this basis, it is believed to be preferable not to use the deepest valley point as a basis, which may be a more clinically desirable removal of a lesser amount of tissue by jacking the presumed best clinical sphere up in height and relying on a more locally tailored empirical approach intended to eliminate any residual bias remaining below the selected best clinical reference sphere.

Along with a two-dimensional view screen displaying the reference line and the internal relationship of the terrain profile, it is desirable to provide an adjustable height offset button and scale markings that can be controlled by a computer mouse to easily change the height of the reference line according to the terrain profile. It is also preferable to provide a similar adjustable scale horizontally positioned to allow the operator to change the diameter of the assumed best clinical sphere, and a digital indicator for the radius, curvature and relative position of the best clinical sphere to the appropriate reference sphere. Thus, based on the clinical assessment by the surgeon which curvature is best for correcting the eyeball without causing any significant deleterious post-operative defects and in which case it is best to remove the least number of cells, the surgeon can also easily change the shape of the assumed best clinical sphere to obtain a flatter curve or steeper best clinical sphere feature. The number of windows displaying the radius value for the appropriate reference sphere, the diopter value of the appropriate reference sphere and the depth or height from the initial position of the appropriate reference sphere to the now displayed height position are correlated with one another such that a change made in one results in a change in the other, which is made automatically by the data processing system and the corresponding numerical value displayed in the display area. Since the height between the initial suitable reference sphere and the actual topographical profile is known for each X-Y reference point and since the height of the assumed best clinical table relative to the height of the suitable reference sphere is also known for each point, the difference in height (and the total cut required) between the topographical profile and the assumed best clinical sphere, which is usually (but not always) located below the initial suitable reference sphere, has been determined using the height deviation monitoring device. What is the best clinical sphere for the patient is determined by the patient's unique topographical contour and the general eyeball shape accompanied by the surgeon's experience that he wishes to enter.

The reference portion also includes an eye axis option provider that allows the operator to determine and select which eye axis (specifically the selection between the N-T (0 °) axis, the up/down axis (90 °), the 45 ° -225 ° axis, and the 135 ° -315 ° axis). This option is designed for use with the best clinical sphere determination device of the present invention, as it allows the operator to pattern the post-simulation effect of the hypothetical best clinical sphere cut profile along a variety of different axes. For example, a surgeon may face a patient with an astigmatic profile along the superior/inferior axis, as seen from a display of a base screen of a color-differentiated refractive profile of a preoperative eyeball. This is considered to be the axis best suited for the initial best clinical sphere determination, and the operator can select the upper/lower axis on which to view the different relationships in the two and three dimensional display between the actual terrain, the initially determined appropriate reference sphere, and the assumed best clinical sphere position. A good representation of the cutting profile required to remove the astigmatic irregularity will be provided. However, the eye may also have a deep local defect that does not belong anywhere along the selected reference axis. If the presumed best clinical sphere contour along the inferior/superior axis is selected, the local defect will be ignored and retained so that some visual degradation will not be retained due to this feature of the corneal surface. If a test is made along an additional axis, such as a 45 degree axis, and the deep local trough belongs to that axis, the surgeon can make a clinical decision as to whether the best clinical sphere cut profile falls within the lowest depth point of the local trough or whether it can produce a cut depth profile, thereby ensuring that the best clinical sphere height in the middle is somewhat above the lowest depth point and below the height determined for the upper/lower axis. Thus, the surgeon can interact with the invention to decide the best clinical sphere appropriate for the particular patient involved, for example by determining on the basis of experience and the displayed initial surface which axis or axes to select for viewing the simulation results, and determining whether the best clinical sphere is at the lowest point of the topographical profile, or including some change set to which is deemed appropriate for the clinic in such a case.

Further, the best clinical sphere cutting profile can be used alone, or in combination with additional cutting features if the surgeon deems this sufficient depending on the patient's condition. As an example, if the patient has an astigmatism causing condition that will be removed with the best set of clinical spheres, but the ablation profile will simultaneously produce hyperopia in the correction of the eye, this can be avoided by adding an additional ablation profile to the eye that produces a more myopic result on the basis of an ablation profile that is either a standard clinical or "normal" profile or that the surgeon has generated himself in a customisation step, for example by selecting different coefficients to alter the ablation profile or by selecting a stored profile (a file containing previously the surgeon's own created profiles that can be used or profiles originally provided by the interface system).

Drawings

FIG. 1 is a block diagram of the flow of data from a patient to a laser system in the system of the present invention;

FIG. 2 is a block diagram of the hardware portion of the system of the present invention;

FIG. 3 is a schematic representation of the stagnant surface irregularities and limited contouring action given by the prior art system;

FIG. 4 is a schematic illustration of the unlimited effect of removing surface irregularities and contouring given in accordance with the present invention;

FIGS. 5A, 5B and 5C illustrate a flow diagram of several processing modules and possibly some cycles between them provided by the preferred embodiment of the present invention;

FIG. 6 is a compression diagram of the flow diagrams of FIGS. 5A, 5B, and 5C with the addition of some possible selection and execution loops;

FIG. 6A is an embodiment of a cutting control apparatus;

FIG. 7 is a flow chart of the process steps performed in one of the reference modules of the interface system of the present invention;

FIG. 8 is a preferred, primary view screen for the reference module illustrating the irregular eyeball topography with emphasis along the 90 axis, a cross-sectional view illustrating the corneal profile along the same axis with an overlapping sub-view, and a reference ablation line for the assumed best clinical sphere positioning that has been moved to a position, thereby resulting in a diameter of 8.6mm and a depth of 24 microns to standard the initial appropriate reference sphere (since the initial reference line has been moved down to the assumed best clinical ablation position without showing the line) and such an assumed ablation profile to design a desired post-operative radius of curvature of 8.03mm and a refractive index of 39.5 diopters.

FIG. 8A shows a two-dimensional profile along a single axis of corneal topography, a two-dimensional profile of a suitable reference sphere, a two-dimensional profile of a hypothetical best clinical sphere that descends therebetween, and a profile of additionally removed cells in the case of a combination reference/myopia correction;

FIG. 9 is the same view screen as FIG. 8 except that the assumed best clinical sphere cut profile has been performed in the simulation with the revised cut profile and the post-operative results of the simulation are shown in the left sub-window section;

FIG. 10 is a plurality of windows pop-up on the main reference module window similar to FIG. 8 except that they illustrate different height selections of reference lines for displaying the presumed position of the presumed best clinical sphere;

FIG. 11 is a plurality of windows pop-up on the main reference block window showing the reference lines of a hypothetical best clinical sphere at the same elevation level relative to the terrain profile, but along different selected axes (0, 45, 90, 135) provided by the reference blocks;

FIG. 12 illustrates a simulation of the combined surgical procedure in the reference module portion of the system of the present invention, depicting a desired combined surgical procedure for astigmatism and regular myopia profile, since highly irregular central astigmatism correction will result in myopia, based on the fact that there is no need to applanate the cornea for the patient and thus a myopia compensation is required to steepen the cornea back to its original shape, with the right side showing the simulated reference ablation result for astigmatism correction and the left side showing the combination of the two hypothetical surgical procedures;

FIG. 13 shows the actual combination of a reference ablation with a regular myopia model, with correction of the 90 degree axis leading to myopia, and the results of the combination treatment shown on the right and left sides;

FIG. 14 shows a comparison between two myopia treatments of +5 diopters acting on the same eye, wherein the right side of the view screen shows the contour of a sphere and the left side shows the same operation of a nonspherical ablation on the same eye;

in fig. 15 the spherical ablation profile at the right side of the screen is +10 diopters and the left side is the same +10 diopter but aspherical profile for the same eye, and the corresponding comparison of the two surgical profiles is shown at the bottom;

figure 16 is a graph of the interactive astigmatism phenomenon simulated for astigmatism correction, which is a disadvantage represented by the mathematical transformation of the reference cut, the predicted topographic results are not very regular, since the surgery depends largely on the use of many factors in a basic formula;

FIG. 17 is a comparison between the simulation formula based on astigmatism treatment on the right and the simulated reference cut on the left;

FIGS. 18A and 18B show the main view screen of the other eye (right eye) of the same patient as in FIG. 9, with FIG. 18A at a presumed best clinical sphere height level and FIG. 18B at a different height level;

FIG. 19 shows two final cut profiles to obtain two differently positioned hypothetical best clinical spheres on the same eyeball, wherein the best clinical sphere on the left side is about 20 microns lower than the right side;

FIG. 20 shows two putative best clinical spheres as in FIG. 19 separated from each other by approximately 20 microns in height for different patients;

FIG. 21 is a view similar to FIG. 20, but rotated upwardly to obtain a different angled view of the cutting profile, which represents a height suitable for delivery to a laser system;

FIGS. 22A and 22B are schematic diagrams of laser pulses applied controlled to ablate only those regions of interest determined by the final ablation profile and designed to apply randomly emitted pulses (avoiding localized heating) to dislodge cellular layers of the cornea (these layers typically relating to different peripheral profiles) when use is complete, displacing a volume of cells as determined, for example, by the ablation profile selected in FIG. 21;

FIGS. 23A, B, C and D show laser calibration results on a substrate of the present invention (showing photographic paper test strips) with layers of different color materials to show different degrees of laser depth produced by the ablation profile matrix output from the interface system of the present invention;

FIG. 24 illustrates a partially cut cutting profile based on a spherical cutting formula, wherein the shape of the central concave portion is controlled by the surgeon-entered radius of the sphere and the width of the zone or opening of the central concave surface of the cutting profile;

FIG. 25 illustrates a partially cut cutting profile (inner wall for multiple curvatures of the cutting profile) based on an aspherical cutting formula, wherein the final shape of the aspherical cutting profile is determined by the values entered by the surgeon;

FIG. 26 is a comparison between the non-spherical cutting profile shown in FIG. 25 and the spherical cutting profile shown in FIG. 24;

figures 27A-H show a variety of possible astigmatic cutting profiles, for which a surgeon can quickly create a clinical plan for use as a reference source, along with accompanying, surgeon's variable equations;

FIG. 28 is a main window of an open "surface treatment" file;

FIG. 29 is an overlapping sub-window showing individual files of terrain data;

FIG. 30 is a window pop-up for selecting one selection handler from a plurality of selection handlers;

FIG. 31 is a normal view window frame;

FIG. 32 is an operation block for inputting cut data in surface processing;

FIG. 33 provides a straight line depiction of the normal (spherical) parameters entered in the viewing frame shown in FIG. 32:

FIG. 34 is a dialog box with multiple adjustable regions associated with the aspheric portion of the surface treatment process;

FIGS. 35 and 36 are schematic diagrams similar to FIGS. 33 and 34, respectively, but in an "aspherical" processing setting;

FIG. 37 is an "aspherical" dialog box with a data entry area for entering cutting data;

FIG. 38 shows an input step of cutting data including selection of a desired reference axis from the ejected selected portion;

FIG. 39 is a straight line profile relative to the reference axis shown in FIG. 38; and

FIG. 40 is a hyperopic eye dialog box with an "enter clipped data" section.

Detailed Description

FIG. 1 is a block diagram of the flow of data from a patient to a laser system in the system of the present invention. As shown in fig. 1, the patient's unique eye topography is scanned and mapped by a suitable corneal topographer. The topographer used preferably provides sufficient data points to provide a good source of data for subsequent data processing performed by the interface system as will be described below. In a preferred system of the present invention, an elevational topographical system, such as the "ORBSCAN II" system manufactured by Orbscan Inc. of salt lake City, Utah, USA, provides a digitized topographical map based on height points taken in units of 10 microns along the X-Y axis and typically varies in height resolution within 1-5 microns. The ORBSCAN II system relies on data from both slit-lamp and Placido disk search methods. Other topographers using, for example, only one of Placido disk and slit lamp techniques may also be used, although the higher precision combination is preferably a standard point from a data source that provides good data for subsequent calculations by the interface system of the present invention.

Fig. 2 is a block diagram of a system 40 of the present invention including a topography system 42, an interface system 44, and a laser system 46. The interface system 44 includes a graphics system 48 coupled to a data processor 50 for performing functions described in detail below. Preferably, the interface system 44 further includes an input interface 52 and an output interface 54 for enabling the data to meet format requirements (if needed) in extracting data from the topographer and outputting data for driving the laser system 46. Among the various functions performed by the interface system, the interface system stores data in a desired form, such as a matrix. The matrix may be stored for a variety of purposes including as a basis for converting data into a color map, where different colors are assigned to different heights to account for the matrix stored in the graphics system 48. The system is then calculated and customized by the surgeon until the desired cutting profile is obtained (as described in detail below), which is specified and placed in a suitable format, such as a matrix, and output to the laser system used via the channels of the output interface. The output interface provides any required conversion to make the final cut data format compatible with the drive parameters of the laser system 46.

The laser system 46 includes a control device (e.g., a binary X-Y scanning mirror) and ancillary control software and hardware for changing the contact position of the laser beam on the eye, for use with a laser generating device such as an excimer laser, although other suitable corneal removal techniques (e.g., fluid jet or mechanical material removal devices) may be relied upon. The control of laser system 46 and the laser beam positioning device of the laser system are not designed to receive the customized, detailed ablation profile and execute instructions output by the interface system, such as the aforementioned X-Y-Z final ablation profile matrix. Preferably the excimer laser has a ceramic head characterized to be capable of operating at a pulse repetition rate of 200HZ or higher and has a stable, controllable power output with an adjustable beam spot that can be adjusted from 1mm to 2 mm. In a preferred embodiment, the laser system is a binary scanning mirror device that moves the excimer beam in the X and Y axes and works in conjunction with an eye tracking system having a scan speed of 2000 to 4000HZ or higher and a centering device that keeps the laser beam centered on the target center (e.g., pupil center) before surgery to ensure that the laser is precisely aimed and precisely triggered relative to the ablation profile at the beginning of the surgery.

A laser system such as Lasersight2000 or Lasersight LSX1 from Lasersight inc (orlando, florida, usa) is provided that is capable of providing laser positioning that is consistent with the direction of the cutting profile output by the interface system of the present invention. Albeit at a lower speed than preferred. As another example of the previously known laser systems, Chiron-Technolas Keracor 117 and 217 laser systems from Chiron-Technolas GmbH can also be used.

Fig. 3 and 4 provide a comparison between the non-customized, non-precisely specified cutting technique of the prior art and a portion of the customized, detailed arrangement of the present invention. An eyeball under laser light (e.g., PRK or LASIK treatment) is shown in fig. 3, wherein a single diameter beam limits the optical prescription of correction, such as myopia correction, to act on the eyeball without taking into account the uniqueness of each individual eyeball relative to the topographical profile. The same can also be said of another prior art ablation technique such as a flying spot scanning technique along an optical formula path (e.g., a circular path or an elliptical path). Fig. 3 illustrates that the resulting eyeball has the same topographical irregularities in the post-operative state as it had in the pre-operative state, due to the non-smooth topography of the eyeball. For example, in PRK treatments, since the lasers used are designed to have a generally constant energy level across the diameter, they ablate a constant thickness along the treated corneal surface, and thus the portion of the eye having an apex in the preoperative condition will have these same apices in the postoperative condition, and are generally true as well relative to the topographical pits. The same is true for LASIK treatment. Because the microkeratome presses down on the cornea during the flaking process and thus any peaks reappear on the exposed substrate surface as the pressure and single thickness of the lamella layer is removed. Fig. 4 illustrates the application of a laser that is consistent with the actual topography of the corneal surface (stroma or more outer layers) after treatment, by using thousands of small beamlets acting on the model and cutting or removing the depth of the irregular topography of the eye, so that a smoothly-mapped corneal topography is produced as shown on the right side of fig. 4.

Fig. 5A, 5B, 5C and 6 illustrate a flow chart of the various processing modules provided in a preferred embodiment of the interface system of the present invention and some possible cycles between them. As shown in fig. 5A, at the beginning, interface system 44 reads data output by the topographer. The best suitable sphere formula as shown in fig. 6 (e.g. the middle sphere relative to the actual topography of the eye) is preferably performed as an initialization step of the matrix formula immediately following the data from the topographer. The best fit sphere is used as a starting point for a preferred reference location, but inevitably it is not the best clinical sphere for the patient as explained later. The best fit sphere is a numerical method of interpolating a surface in an irregular surface, such as the irregular topography of the eyeball. Various mathematical methods such as a spline surface technique or a Bezier technique may be used.

Presented below are the outputs of the preferred graphical system of the interface system with reference to fig. 28 to 40.

FIG. 28 illustrates a main window of an open surfacing file. The accompanying step includes reading data from the topographical machine, which may be stored in a separate file as shown by the overlapping sub-windows shown in fig. 29.

The data read from the topographical machine provided a reading structure, the result of which was a 100 x 100 dot data matrix over a 10mm x 10mm rectangular area of the surface of the eyeball. This means that one dot is read in one step per 100 microns. This step allows the operator to select different eye case records to ensure that the surgeon performs different procedures or variable simulations that will generate the control data files for surgery on the laser machine. A selection processing step from the plurality of selection processing sections may then be performed. FIG. 30 illustrates a selection process step.

The choose selection process corresponds to a magnification option in the surface treatment menu bar and allows the user to select three different options:INTERACTIVEthe cutting is carried out, and the cutting is carried out,REFERENCEcutting andPRESBYOPIA。

INTERACTIVEthere are three options for cutting:Normal，AsphericalandAstigmatic. These options direct the surgeon to three basic procedures.

NormalIs a procedure that allows the operator to perform or simulate a cut with a spherical parameter called normal. This procedure corrects myopia and hyperopia.

FIG. 31 shows a Normal window frame. In the surface processing, there is also provided an input of cutting data as represented by the processing block in fig. 32. Fig. 33 provides a straight line plot of the normal (spherical) parameters entered in the view frame of fig. 32.

The final box is an attribute dialog box containing several parameters to be filled in to determine the profile and depth of the cut.

Correction is the first area. The zone accepts negative numbers and positive numbers, where negative numbers define a near vision model and positive numbers define a far vision model. The units of this area are the Diopters.

Zone Diameter is the next area and defines the cutting range and functions such as boundaries.

Radius of Curvature is the last region and allows selection of the same eyeball CurvatureDiopterDifferent curvature profiles of the values.

AsphericalIs an option that allows direct interaction with parameters for near and far vision correction but with non-spherical contours.

FIG. 34 illustrates a dialog box with the following regions:

correction is denoted by sight and includes a negative number for near vision and a positive number for far vision.

Factor is a suitable parameter that allows the form of the equation to be changed in order to achieve the desired profile.

Zone Diameter is the next area and defines the cutting range and functions such as boundaries.

Radius of Curvature is the last region and allows different Curvature profiles with the same diameter value to be selected according to a particular eyeball Curvature.

Interior Diameter is a parameter used only in presbyopia treatment and indicates the inner layer that should not be accessed.

FIGS. 35 and 36 show views similar to those of FIGS. 33 and 34, but in the "statistical" processing state.

Exteror Diameter is used only in presbyopia treatment in the same way as the previous zones and allows to cut off the outer effects according to a curved profile.

AstigmaticIs the last option and is associated with a dialog box containing drawing buttons that provide a description of the relationship between the different surface contour representations of the graphic.

FIG. 37 illustrates an Astigmatic dialog with a data entry area for cut data entry, described below.

Correction is expressed as a Dipter, defining the precise number of cells to be removed.

Zone defines the cutting range and functions such as boundaries.

Radius of Curvature is the last region and allows different Curvature profiles with the same diameter value to be selected according to a particular eyeball Curvature.

Further, fig. 37 illustrates regions corresponding to coefficients depending on the selected button and operation such as contour correction.

REFERENCEIs an option that allows viewing of the corneal profile along different axes based on the above. These major axes are 0, 45, 90, 135 degrees. Once the steepest or flattest axis is selected, the surgeon may selectTo perform different treatments to achieve what is best done according to his experience.

Fig. 38 illustrates the step of inputting cut data, including selecting a desired reference axis from the pop-up options, while fig. 39 shows a profile corresponding to the reference axis selected in fig. 38.

The corneal profile can be enlarged in the designated axis by the appliance option and an interactive graphic displayed that allows the operator to slide a straight line over the corneal profile and simulate a blade that can virtually remove the cells shown in those figures.

Further, the model provides other interactive parameters to vary the diameter of the cutting ring, transition ring, and the average curvature and radius that show the particular profile.

PRESBYOPIAIs the last option, there is a dialog box with four parameters, allowing the operator to change the cutting profile finely.

Fig. 40 illustrates a far vision dialog box with an input cut data portion.

Diopters essentially represent the depth of cut.

Factor is a suitable parameter that allows the form of the equation to be altered in order to obtain the desired profile.

Interior Diameter is a parameter indicating an inner layer that cannot be contacted.

Exteror Diameter allows the outer effects to be truncated according to the contour of the surface.

As shown in particular in fig. 3, 5A-C, 6 and 7, the surgeon has the right to select a reference module of the invention. The reference module relating to the determination and use of the best clinical sphere is particularly well suited to highly irregular eye features relating to astigmatism or myopia correction, but is also well suited to more typical astigmatism and myopia corrections and as shown to provide a more predictable result for comparison with, for example, a formula based on astigmatism correction.

A typical block diagram of a laser cutting control apparatus is shown in fig. 6A. It will be appreciated that the various devices shown as blocks in the figures are preferably completed using software and therefore these devices may be integrated with a software programmed single chip for completing the device. However, those skilled in the art will also appreciate that each device represented by a block in the figures can additionally be equipped with wired circuitry.

The apparatus shown in fig. 6A includes a topography data search apparatus that receives a corneal surface elevation map from a topographer. The searched corneal topographic data may be displayed by a corneal surface display device. Preferably, the surface is displayed as a color-coded surface elevation map. A best fit sphere calculation means produces a spherical fit of the data required by the terrain data search means. The spherical fit is made along an axis selected by the user or on the basis of a preformed defect axis. Based on the searched topographic data and the best chosen appropriate sphere, a reference cutting profile is generated and interactively altered to obtain a surgically acceptable reference cutting profile. The user may also select and personalize other ablation profiles to optimize the profile for an individual's cornea. The device has means for interactively generating the profiles. The preferred embodiment includes an interactive spherical cutting profile means, an interactive aspherical cutting profile means and an interactive astigmatic cutting profile means.

The cutting profile selection, comparison and display device allows the user to select one cutting profile to be displayed and considered for the cutting process. One, two or more cut profiles may also be displayed so that the user may have an intuitive comparison of the profiles. The predicted corneal shape display device prepares and displays a predicted corneal surface elevation map that would appear if the selected ablation profile were applied to the patient's cornea. The prediction is calculated from corneal topography data minus ablation profile and can include corrections based on a physiological model of the physical properties of the cornea and therapeutic properties of the cornea. If the predicted corneal shape is satisfactory, the ablation profile is written to the laser control data device to allow a corneal ablation to be performed. In some cases it may be desirable to merge one reference cutting profile with the reference cutting profile of the other cutting profile. An example of this would occur when performing astigmatic correction with a reference ablation and result in a myopic cornea. In this case, the hyperopic cut profile can be combined with the reference cut profile to obtain a combined cut profile that can correct astigmatism in a manner that does not produce myopia. The outcome of the execution of the merged ablation profile may be predicted by comparison with a corneal surface elevation map provided by a predicted corneal shape device. As previously described, if the predicted corneal shape is satisfactory, the ablation profile is determined and then written to the laser control data device to allow a corneal ablation to be performed.

Fig. 8 illustrates a preferred, primary view screen for the reference module, illustrating the irregular eyeball topography with emphasis on the 90 ° axis, with an overlapping sub-view illustrating the cross-sectional view of the corneal profile along the same axis, and the reference ablation line assuming the best clinical sphere positioning has been moved to a position whereby the 8.6mm diameter and 24 micron depth are obtained with reference to the initial appropriate reference sphere. The best clinical ablation reference line is shown as being substantially at the lowest point of the topographical profile along the 90 degree axis. The same overlapping sub-window appears in the lower left corner of fig. 11, where fig. 11 further provides other overlapping sub-windows for displaying the same presumed best appearance of a clinical sphere but along an axis that is less than the available of the reference module of the present invention. Figure 10 on the other hand shows a number of different profiles assuming the best clinical sphere. The overlapping window in the upper left corner of fig. 10 shows a hypothetical best fit clinical sphere reference line which has been raised upwardly relative to the initially determined best fit reference sphere given in the window in the lower left corner of fig. 10. The "deep" flag appearing in each overlapping sub-window indicates the height difference between the elevated presumed best clinical sphere reference line and the original best fit sphere reference line. Thus "deep" in the sub-window of the lower left foot shows 0, indicating that the presumed best clinical sphere is at the same level as the initial best fit sphere. The value of deep in the upper left sub-window is positive 76 indicating that the assumed best clinical sphere reference line is above the original reference line. Along with the depth values, each pop-up sub-window in FIG. 10 displays the radius and curvature (in diopters) of the assumed best clinical sphere. The height of the reference line is easily changed by using a sliding scale on the right side of the outline grid in each sub-window. In addition, a horizontally sliding scale allows the surgeon to control the diameter of the assumed best clinical sphere cutting profile.

Fig. 8A illustrates a two-dimensional profile 100 along a single axis of corneal topography (e.g., representing an exposed corneal stromal topography), a two-dimensional plot of a suitable reference sphere 102, and a two-dimensional plot of a lifted, presumably best clinical sphere. In addition, 106 of FIG. 8A shows that additional cell removal may be required in the given situation, where an added circle ablation to compensate for hyperopia is considered to be required to compensate for any potential corrective change, as shown in the simulation of the best clinical sphere ablation selected in the reference block. At the bottom of the primary topographic window on the surface of the eyeball, "Diff" is displayed. This value is equal to the difference in height at any point on the X-Y plane, specifically equal to the difference in actual terrain minus the appropriate reference sphere plus the difference in height of the appropriate reference sphere minus the best clinical sphere selected (i.e., Diff ═ topography-appropriate reference sphere) + (appropriate reference sphere-best clinical procedure sphere). The value may be selected along any location on the terrain position on the intermediate master terrain map by moving the cursor to the required position and clicking. The diameter of the set point (based on 2 times the radius of the cursor out of the pupil) and the diopter value are also displayed below the main topographic map. Fig. 18A shows an example of moving the cursor to a specific position of the main map.

Fig. 8A also shows the aforementioned "deep" value 110, representing the difference between the appropriate reference sphere profile and the best clinical sphere profile, relative to a particular point along the same axis. Fig. 8A also shows a combination involving an increased cut (e.g., hyperopic equipartition profile) combined with the best clinical sphere cut selected in the reference portion of the interface system. More detailed discussion regarding the combined cutting profile will be given later. The final cut profile coordinates or data output to the laser system are determined based on the known parameters of the incremental equations determined by the far vision cutting ring (e.g., another matrix is based on a 360 degree rotation of the selected two-dimensional far vision cutting profile). Since the terrain matrix (or other means of fixing the markers in a workable medium), the appropriate reference sphere matrix, the best clinical sphere matrix, and the height matrix of the rotated far vision profile are known, the entire cutting profile (representative of the cells to be removed) matrix (one height value indicated at 115) can be determined by using these determined parameters. For example, the cut is determined by the distance 112 between the known surface matrix and the best clinical sphere matrix plus the increased depth 113, or the height difference 116 between the known terrain and the appropriate reference sphere plus the height difference 110 between the appropriate reference sphere and the best clinical sphere plus the distance 113. Various other values may also be displayed and/or utilized such as an increased distance 114 between the distance vision cutting ring and the appropriate reference sphere.

The surgeon makes an initial decision based on what is believed to be the best clinical sphere height for the various assumptions of the same 90-degree axis profile displayed in each of the sub-windows shown in FIG. 10. If the decision is made to consider a lower height or-24 depth value best for the condition, then the surgeon may proceed to consider how to perform the initial selection of the best clinical sphere along the other axis options of 0, 45, and 135 degrees. As described above, FIG. 11 shows the clinical sphere initially considered to be the best taken along each of the four axis options. In this manner, the surgeon may consider whether the clinical sphere that was initially considered to be the best is still considered to be the best when its positioning relative to the actual topography of the eyeball is analyzed at different axial positions. After determining that the negative defect did not affect the initially considered best clinical sphere, the surgeon can then activate the "apply" function key to see what the simulated postoperative eyeball was with all cells on the best clinical sphere removed, providing a cutting profile designed to produce a desired postoperative curve radius of 8.03mm and refractive index of 39.5 diopters.

Figure 9 shows the results of determining activation of the apply function according to the best clinical sphere profile for the above described effect. Fig. 9 shows this actual eyeball topography matrix in a larger topographical view, where the left side of the view shows the corneal profile along two axes (here 0 and 90 degrees) and the two figures above are the simulated resultant eyeball profile, and the ablation topography and ablation profile to be completed to remove the cells that are needed to remove all the cells between the surface of the eyeball represented in the larger topographical display and the best selected clinical reference sphere. The analog output is typically displayed as a harmonic color close to green or achromatic "0".

Figure 12 illustrates another example of how a surgeon can use the invention to adapt the cutting profile employed to the needs of the most appropriate patient individual, in this case involving a combined reference and standard cutting profile, the combination of which is made by the interface system, for example, to form a single cutting profile for use in guiding the laser system (e.g., the system determines the best single cutting profile to form in a single laser driven on the basis of lower height values supplemented by the best clinical sphere to be effected and the required supplemented cutting depth and matrix values of features deemed necessary for normal equation correction). The particular combined simulation in figure 12 shows a surgical procedure for astigmatism and the regular hyperopic profile required because the highly irregular correction of intermediate astigmatism would cause hyperopia due to corneal flattening during the reference ablation to the extent that the patient does not want. That is, the reference ablation in this case inherently produces a myopic correction that results in some degree of unwanted hyperopia, and this unwanted hyperopia can steepen the cornea back to its original shape by ablation with hyperopia correction (annular zone of ablation). The right side in fig. 12 shows the simulated reference cutting result and the left side shows the proposed combination of the two procedures. In the same way the surgeon can combine the reference cut with near and far vision and the surgeon can do the same for astigmatism using the formula in the present invention.

Figure 13 shows a combination of reference ablation and regular myopia patterns based on the fact that the correction results in myopia on the 90 degree axis. In other words, a partial hyperopic corrective ring is inherently formed as part of the ablation process on a portion of the cornea during removal of cells belonging to the best selected clinical sphere. Thus, a model of myopia correction is provided for compensation. The right side of figure 14 shows the reference ablation and the left side shows the results of the combination treatment. The intermediate portion removed by the myopia correction mode can be seen by the central display illustrated by the ablation profile selected along the 0 degree axis in the upper left view under the heading "corneal profile", while the corresponding ablation profile that effects the removed central cellular portion is preferably displayed by the ablation profile along the same axis that appears in the lower left corner view.

As shown in the flow chart of fig. 5A, the surgeon is able to determine the eyeball correction involved, either by not advising to use this reference module alone or in combination with one of the sub-modules of the interactive module relating to normal, aspheric, astigmatic, but instead advising to use the interactive sub-module alone. For example, in the case of a substantially regular pre-operative corneal topography, the use of a cutting profile based on a spherical or aspherical formula can correct optical defects in both hyperopic and myopic eyes. In the case of astigmatic corneas, an ablation profile can be generated by a portion of a specific library function specifically created and optimized for correcting astigmatism. These are situations that the wave surgeon deems not to fall into the category of irregular corneal topographic conditions, where a reference ablation profile is created to correct topographic irregularities and combined with a spherical, aspherical or astigmatic profile to correct hyperopia, myopia and astigmatism, among other common corneal defects. The combination of reference and astigmatic mode correction is not impossible but, as explained further below, the reference module is sufficient to cope with most astigmatic correction requirements. As described above, the result of such combined merging is a single cutting profile that is used to control the cutting laser. The result of the use of such a merged profile, in turn, is a successful orthokeratology that removes a minimal amount of stromal cells. Figure 24 shows a three-dimensional cross-sectional view of a spherical farsighted cutting profile. Figure 25 shows a three-dimensional cross-sectional view of an aspherical farsighted cutting profile. The smoother the surface of the non-spherical cutting profile on the spherical cutting profile gives better corneal treatment and improved long-pair stability of the correction.

Fig. 26 shows a comparison between a spherical cutting profile and an aspherical cutting profile for presbyopia correction. Profile 1 shows a typical spherical cutting profile where the shape of the central depression portion of the profile is controlled by a given sphere radius and width of the opening of the depression portion. The radius and width parameters can be selected independently of each other by the surgeon to customize the ablation profile for a particular cornea. Profile 2 shows an aspherical cutting profile in which the shape is determined by the corresponding function for presbyopia or myopic eyes and the shape of the transition zone is controlled by appropriate selection of parameters, radius of curvature, inner diameter and outer diameter, of the zone size selected to tailor the cutting profile to a particular cornea. The non-spherical function itself is a formula based on the bi-square component and the arctan function.

When the cornea is astigmatic but the overall corneal topography is regular, a particular function can be selected from a library of functions. An example of functions included in the function library for astigmatism correction is shown in fig. 27. On the surface of each library in fig. 27 is a mathematical expression representing the cutting profile determined by the corresponding function. The astigmatic correction function can be tailored to a particular cornea by the surgeon adjusting the systems a, b, c, d, f, h, etc. Note that also below the screen heading "simulated ablation" is an earlier depiction and description of the astigmatism reference ablation library, accompanied by tools for changing specific parameters under the control of values entered by the surgeon.

As shown in FIGS. 27A-H, there is one for each equationA common basis "(ax)²-bx⁴-cy⁴+ d) "plus different ends of the equation, some of which have the same component and vary between + or-. As shown in fig. 27H, double dune terrain is one possible result.

The predicted ablation treatment results may be obtained by subtracting the ablation profile from the topographic map of the cornea and the predicted corneal surface results may be displayed. Fig. 14 and 15 show screen images comparing spherical cuts and non-spherical cuts. A graphical corneal topography map is displayed in the middle of each map. The bottom right drawing is the selected spherical cutting profile. The upper right figure is the predicted corneal topography following laser ablation of the corneal stroma according to a spherical ablation profile. The bottom left shows an aspherical cutting profile. The above-described non-spherical cutting profile (upper left corner) is the predicted corneal topography following laser ablation of the corneal stroma according to the non-spherical cutting profile.

Figure 14 shows the contrast between two +5 diopter treatments for myopia. The non-spherical nature of the ablation profile is beneficial in providing a smoother transition in some instances, but it is helpful for the surgeon to image the results of each eye simulation because the cell profile removed in each is different. The comparison screen of fig. 14 provides the surgeon with such a comparison tool to facilitate clinical judgment based on the needs of a particular patient. FIG. 15 provides another example of the advantages of the comparative mode between the aspherical cutting profiles, showing that one aspherical channel avoids what is considered an overcut circle (lower right corner), which would not occur for the same +10 diopter calculation for an aspherical channel.

The middle of figure 16 is a graphical corneal topography map and the lower left corner is the ablation profile for astigmatic correction. The upper left hand graph is the predicted corneal topography following laser ablation of the corneal stroma according to the astigmatism function ablation profile. Fig. 16 also shows that simulations that enable comparison of a patient's previous post-operative state with incremental treatment will provide additional treatment to the patient's previously treated eye based on the new ablation profile or previously completed simulations that are deemed most suitable for comparison. The results of figure 16 also show that the predicted topographical results of the mathematically determined ablation treatment are less predictable than the reference protocol due to the control of the multiple correlation coefficients in the mathematical approach under the sub-interactive astigmatism module.

Figure 17 shows an example of a comparison between a reference scheme and a specific cutting model and the use of an interactive scheme according to the astigmatism sub-module. The left side of the window shows the reference scheme and the right side shows the method of the scheme, which is also helpful for the surgeon to decide which method is better suited for the situation (clearly the reference channel produces a better result for a particular patient).

Fig. 18A and 18B are the primary viewing windows of the other eye (right eye) of the same patient in fig. 9, with fig. 18A at the same elevation level as the presumed best clinical sphere and fig. 18B at a different elevation level. Fig. 19 shows that two alternating final ablation profiles achieve two differently positioned, presumably best clinical spheres on the same eye, with the left best clinical sphere positioned 20 microns lower than the right. Figure 20 shows that for different patients, the two hypothetical best clinical sphere settings seen in figure 19 are approximated in views differing in height by about 20 microns. These descriptions may be provided on a graphical screen to allow the physician to further view the situation. The ability to rotate the view of the profile may be included to obtain a different viewing angle for the amount of cells in fig. 21 intended to be cut with the cutting profile of fig. 20. The matrix with the resulting determined ablation profile is transmitted by the interface system to the laser system via the output interface to control the movement of the laser beam to produce the desired ablation in the eye.

Fig. 22A and 22B show a schematic representation of the preferred manner in which laser pulses are applied, including controlling a preferred laser positioning control device, which is preferably an X-Y based scan control system, which is preferably adapted for drawing along the preferred elevation of the Z axis mentioned above relative to the X-Y plane. The cutting profile data packet (e.g., a file with a final cutting profile determination) provides the information needed to control the motion of the laser beam to cut only those regions of interest defined by the final cutting profile. In the preferred embodiment, the laser is first directed to apply a series of random pulses to one or more regions on the cornea corresponding to one or more base regions of the ablation profile. The process is repeated in sequence by applying the laser pattern to the cell area corresponding to a height slice falling within the ablation profile. This ablation technique is schematically illustrated in fig. 22A, where, at the beginning, a series of pulses act along a single X-Y cell plane (in a random fashion across the X-Y axis plane to avoid local heating) indicated at L1, and their shape is governed by the corresponding edge or edges represented by the ablation profile as in fig. 20. After the first region represented by the base plane is complete, the laser repeats the random action of pulses within one or more edges of the X-Y clipping of the level along the next cutting profile level (the next pulse unit packet is represented by the brick-like box falling within level L2 in fig. 22A). This is repeated until no more cells remain in the cut profile that exceed the height limit (L1, L2, L3 … … Ln).

Fig. 5A-C also include a hyperopia module, which is an option that the surgeon can select to replace other reference and interactive module options (although combinations of reference/hyperopia formulas as in the combinations previously described are also possible). Under this module the surgeon is able to treat hyperopia by applying a hyperopia correcting cutting profile in accordance with the parameters mentioned above and contained in all the settings contained in U.S. patent nos. 5,533,997 and 5,928,129. The distance vision correction may also be performed as a separate ablation operation following an earlier refractive ablation operation, such as an astigmatic correction.

Fig. 23A-D illustrate a plurality of cut calibration operations and a cut to be approached or completed controlled by a cutting profile determined by the interface device of the present invention. The substrate material shown in the patterned window (image portion) of fig. 23A-D shows a substrate comprising a material capable of showing the depth of cells to be removed by the laser following the received ablation profile. In a preferred embodiment, a photographic paper that has been exposed and subsequently blackened is placed under the laser profile and with or without the uncovering of thin layers of different colors is dependent on the extent of the laser exposure, so that these areas subjected to the action of repeated pulses exhibit a different color than areas not subjected to these actions. The substrate thus provides a good pattern for the cutting pattern of the eye to be formed (as opposed to the prior art profile of a base layer which only shows the cutting profile acting on a black single colour photographic paper). The substrate may also be formed so that the displayed color layer generally corresponds to the color appearing on the topographical map so that similar image codes are used. The lower left corner of each window of fig. 23A-D may also be provided with a predicted or determined total cut cycle time (e.g., 15 seconds for fig. 23A) and a larger and focused time specification to give the actual time that the laser has been driven to the cut color model shown in the figure (e.g., 14 seconds in fig. 23A).

In performing an ablation of a patient's eye, a laser is driven to remove a quantity of cells from the eye as indicated by the ablation profile data packet. The data packet may be delivered directly to an associated laser system or the interface system may be used in a round robin fashion. For example, the topographical data file may be converted on a suitable medium such as a computer diskette and the diskette may be sent to a remote location where the interface system is located, and/or the data package may be delivered by other means, such as sending an e-mail. The surgeon at the location of the interface system can process the resulting topographical data and determine what is the best clinical scenario with the aid of the interface system. The cutting profile data packet may then be transmitted to the device actually performing the surgical procedure. A surgeon with more experience and expertise in this manner can provide a cutting profile package. Other possible advantages made by the present invention are that it allows one surgeon to obtain suggestions or improvements in order to prepare a copy cut with the interface system to transmit data to another surgeon who owns the interface system of the present invention. Furthermore, due to the general nature of the present invention, the combination of the topographer/interface system may be independent of the laser system, and the laser system or topographer located at a remote location may be located at a location remote from the interface system and/or laser system.

The present invention is well suited for use in LASIK procedures, which specifically involve a procedure involving anesthetizing a patient and ablating at least a portion of the cornea to expose the corneal stroma. The laser system is then used to cut a portion of the corneal stroma, the laser system performing a cut indicated by the clinical cut profile determined by the interface system.

Claims (37)

1. An interface system for providing eyeball reshaping data, comprising:

means for receiving eye topography profile data;

means for providing clinical reference cutting profile data; and

means for adjusting the relative difference between said clinical reference cutting profile data and said eye relief profile data in response to operator interactive input, thereby changing the eye volume data represented by the relative difference between said clinical reference cutting profile data and eye relief profile data, and wherein said means for providing clinical reference cutting profile data comprises means for initially providing a suitable reference profile for said eye relief profile data, and said adjusting means comprises means for adjusting a suitable reference profile sample in response to the position of the initial suitable reference profile, and the initial suitable reference profile represents a pre-adjusted clinical reference cutting profile and the adjusted suitable reference profile sample represents an adjusted clinical demonstration profile.

2. The interface system of claim 1, further comprising:

means for providing information to an interactive operator regarding changes in eye volume data resulting from adjustments in relative differences between said clinical reference cutting profile data and said eye topography profile data.

3. The interface system of claim 1, wherein said means for providing a suitable reference profile comprises means for generating a suitable reference profile from said eye contour profile data after said eye contour profile data is received by said means for receiving said eye contour profile data, said adjusting means comprising means for sliding adjustment by a plotter of said suitable reference profile.

4. The interface system of claim 1, wherein the eye contour data is the contour data from the exposed surface of the eye and the appropriate reference contour is based on the best appropriate reference sphere formed in view of the vertices in the valleys in the exposed surface of the eye.

5. The interface system of claim 4, wherein the best fit reference sphere is based on an average or median sphere using one or both of spline subdivision and Bessel surface techniques.

6. The interface system of claim 1, further comprising means for providing an eye contour based on said eye contour data, and wherein said means for providing information to an interactive operator comprises a graphical system, and said graphical system comprises means for describing an eye contour, said appropriate reference contour, and a relative adjustment in position with respect to said clinical demonstration contour and said eye contour.

7. The interface system of claim 6, wherein said graphical system traces a suitable reference profile at the beginning of a reference positioning and the clinical demonstration profile is displayed kinematically relative to said eye contour description when said adjustment device is operated.

8. The interface system of claim 7, wherein said graphical system provides a relatively positioned view of the eye contour and a clinical demonstration contour within the same graphical screen, wherein said clinical demonstration contour is vertically movable relative to a fixed eye contour, and said graphical system further comprises means for graphically depicting a cutting model based on a quantity of eye tissue located between said eye contour and said clinical demonstration contour.

9. The interface system of claim 8, wherein the graphical system provides a view of the relative positioning of the eye contour, the appropriate reference contour, and the clinical demonstration contour within the same graphical screen.

10. The interface system of claim 8, wherein the eye topography profile data is topography profile data from an eye exposed surface, the suitable reference profile is based on a best suitable reference sphere formed taking into account peaks of recessions in the eye exposed surface, and the suitable reference profile is a straight line description of the best suitable reference sphere.

11. The interface system of claim 4, wherein the eye topography profile data is topography profile data from an eye exposed surface, the suitable reference profile is based on a best suitable reference sphere formed taking into account recessed peaks in the eye exposed surface, and the suitable reference profile is a straight line description of the best suitable reference sphere.

12. The interface system of claim 3, further comprising means for contour calculation of said clinical demonstration contour.

13. The interface system of claim 12, wherein said clinical demonstration contour comprises a contour portion of a sphere and said means for contour calculation comprises means for changing a curvature of said contour portion.

14. The interface system of claim 6, further comprising means for converting the eye contour profile data and the clinical demonstration profile data into topographical color data, and said graphical system comprises means for representing a simulated post-operative color topographical map of the results obtained on the eye contour when eye material located on the clinical demonstration profile is removed.

15. The interface system of claim 14, wherein said graphical system includes means for representing a cutting profile represented by a quantity of eye material between said clinical demonstration profile and an eye contour profile.

16. The interface system of claim 14, wherein said graphical system further comprises means for simultaneously representing said post-operative simulated color topography and said eye contour color topography.

17. The interface system of claim 6, wherein said graphical system includes means for simultaneously representing a plurality of graphical images representing a plurality of differently positioned clinical demonstration contours relative to the contour of the eye contour.

18. The interface system of claim 6, wherein said graphical system describes said clinical demonstration contour at a location above said suitable reference contour location with said adjustment device moving said clinical demonstration contour further away from the center of the eye and above said suitable reference contour, and describes said clinical demonstration contour at a location below said suitable reference contour location with said adjustment device moving said clinical demonstration contour further towards the center of the eye and below said suitable reference contour.

19. The interface system of claim 17, further comprising a depth-specific view screen that displays height adjustments of the clinical demonstration profile relative to the appropriate reference profile.

20. The interface system of claim 2 wherein said eye contour data is presented as a set of eye contour data represented by X, Y and Z coordinates, and said means for providing a clinical reference cutting profile comprises means for providing a clinical demonstration profile data set represented by X, Y and Z coordinates, and said adjustment means comprises means for changing said clinical reference cutting profile data set based on an operator adjustment input relative to said eye contour data set.

21. The interface system as claimed in claim 20, wherein the eye relief profile data is presented by way of an eye relief profile data set, the interface system further comprising comparison means for comparing the data set relating to the positioning of the eye relief profile data set by two different operators with the data set of the clinical reference cutting profile data, adjusting the relative difference of the clinical reference cutting profile data and the eye relief profile data with respect to a common vertical profile extending through the clinical reference cutting profile data and the eye relief profile data.

22. The interface system of claim 1, further comprising means for comparing the data sets of the eye relief profile data and the data sets of the clinical reference cutting profile data in relative data sets positioned so that two different operators adjust the relative difference between the clinical reference cutting profile data and the eye relief profile data relative to a common vertical section extending through the clinical reference cutting profile data and the eye relief profile data.

23. The interface system of claim 22, further comprising an axis adjustment device including means for changing the position of said common vertical profile to provide data regarding the relative difference in vertical spacing between said clinical reference ablation profile data and said eyeball topography profile data.

24. The interface system of claim 23, further comprising means for visually depicting said eye contour and said clinical demonstration contour relative to another of a plurality of positions along said common vertical section.

25. The interface system of claim 1, wherein said eye contour data is presented as an eye contour data set, said interface system further comprising means for determining a ablation data set based on a difference between said eye contour data set and said adjusted clinical exemplary contour data set after adjusting said clinical exemplary contour data set.

26. The interface system of claim 1, further comprising means for determining an adjusted ablation data set following said data set of clinical demonstration profiles based on a difference between values of said data set of eye relief profile data and said data set of adjusted clinical reference ablation profile data.

27. The interface system of claim 26, further comprising means for visually describing a cut setting based on said set of cut data.

28. The interface system of claim 26, further comprising means for outputting said ablation data set to an eye reshaping means.

29. The interface system of claim 1, further comprising means for inputting a further correction data set based on a predetermined profile, and means for blending the clinical reference cut profile data with the further correction data set.

30. A cut data generation system comprising:

a topography system having means for providing topographical data of the surface of an eye;

an interface system having means for receiving topographical data of an eye surface from said topographical system, said interface system including means for providing a base reference profile data set, and said interface system including means for changing the relative data values between said base reference profile data set and said topographical data set of an eye surface in response to operator interactive input, and said interface system further including means for comparing the changed relative data values to determine a cutting model data set, and said interface system further including means for generating a topographical profile description based on said topographical data and means for generating a description of a reference cutting profile across a predetermined eye cutting zone diameter, and said means for changing the relative data values including means for adjusting at least one of said descriptions relative to the other descriptions, and said interface system further comprises means for outputting said cutting model data set.

31. The system of claim 30, further comprising means for magnifying the description of the topographical profile along a selected axis and the means for generating the description of the reference ablation profile presents a rectilinear pattern simulating a blade and adjustable in position relative to the magnified description of the corneal topography.

32. A system for reshaping an eyeball, comprising:

a topography system having means for providing topographical data of the surface of an eye;

a laser system having an eye cutting device;

an interface system having means for receiving topographical data of the surface of the eye from said topographical system,

said interface system including means for forming a base reference profile data set, and said interface system including means for varying the relative data value difference between said base reference profile data set and said eye surface topography data set, and said interface system further including means for comparing the variation of the relative data value difference between the base reference profile data set and said eye surface topography data set to determine a follow-up adjusted ablation model data set, and wherein said means for comparing the variation includes means for adjusting at least one profile description of said eye surface topography data and a profile description of said base reference profile relative to other profiles, said base reference profile description being a sample of a reference sphere for the whole corneal region of the eye, and said interface system further including means for outputting said ablation model data set to said laser system, means for causing said eyeball cutting means of said laser system to complete an in-eyeball cutting model corresponding to the output cutting model data set.

33. The system of claim 32 wherein said means for varying said relative data includes means for varying said base reference profile by operator interactive input relative to a fixed topographic profile.

34. The system of claim 33, further comprising means for graphically presenting to an operator information of changes in the difference of data values between said topographical eye surface data and said data set of base reference contour data.

35. An interface system for developing eyeball reshaping data, comprising:

means for receiving eye topography profile data;

means for presenting said eye contour data to an operator of the interface system;

means for setting a reference data set relative to said eyeball topographic profile data;

means for presenting to an operator a reference data set in combination with said data set of eye contour data;

means for determining eye volume data representing the relative volume of eye material falling between said reference data set and said data set of eye topography profile data;

means for altering the eye volume data by an operator's calculation resulting in a change in the difference in data values between said data set of eye topography profile data and said reference data set,

and wherein said means for representing said eye contour data comprises a graphical means for delineating a data set of eye contour data in a first eye axis plane in a contour manner, and said means for representing a reference data set also displayed by said graphical means in a contour manner along the first eye axis plane, and said graphical means further comprises means for displaying an adjustment of the relative position between said contours on said means for changing based on an operator's calculation of at least one of said contours relative to the other contours.

36. The system of claim 26, further comprising means for merging an ablation model providing the adjusted clinical reference ablation profile with a corrective ablation model to counteract the effects of myopia or hyperopia due to reshaping of the ablation model providing the adjusted clinical reference ablation profile.

37. The system of claim 1, further comprising means for magnifying the description of the eye relief data along an axis and the adjusting means comprises adjusting a line graph representing the sample of the first reference profile relative to the magnified description of the eye relief data.