JP2003532484A - Method and apparatus for controlling a high resolution high speed digital micromirror device for laser refractive ophthalmic surgery - Google Patents

Abstract

  (57) [Summary] The laser eye surgery system includes a laser for generating a laser beam capable of performing a refractive correction, an optical system for adjusting the shape and condition of the laser beam, and directing the shape and condition adjusted beam to the eyes. And a computer system for controlling the mirrors of the DMD, and a target tracking system for tracking the position of the eyes and providing feedback to the computer system.

Description

Detailed Description of the Invention

This application is related to US patent application Ser. No. 09/524, filed Mar. 13, 2000.
No. 312, a continuation-in-part application, which is hereby incorporated by reference in its entirety.

The Government of the United States of America has a paid non-exclusive license to the present invention, as defined by Permit R44 EY11587 awarded by the National Institute of Ophthalmology, National Institutes of Health.

BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates generally to eye surgery. More particularly, the present invention relates to systems and methods for laser refractive eye surgery.

2. Prior Art The field of laser refractive surgery (or laser keratotomy) has developed rapidly over the last few years, with numerous lasers and algorithms for correcting human vision. Currently, systems use laser wavelengths from the ultraviolet (excimer) to the infrared to alter the shape of the cornea in a pattern that is calculated and that allows the eye to properly focus. For example, in the treatment of myopia, excimer lasers are used to remove tissue from the cornea, ie, ablation ablation, to flatten the shape of the cornea. Some companies use infrared (IR) energy to treat myopia by transforming corneal tissue into a new shape by a “thermal” method that is the opposite of ablation by excimer wavelength ablation. ing. Correction of hyperopia is done by ablating the cornea's outer edge tissue (with excimers) or by steepening the cornea by deforming it (with IR energy) to its new shape. . The correction of astigmatism, that is, the correction of myopia and hyperopia requires the removal of tissue in a more complex pattern or transformation into new morphology with a laser.

The first system approved by the FDA (Food and Drug Administration) is to deliver beam-shaped laser energy based on the broad-beam approach, ie based on thin lens theory and paraxial optics applied to a single sphere. Therefore, the refraction is corrected. The shape of the beam is defined by the Mannerlyn derivative (C.R.
Munnerlyn, S .; J. Koons and J.M. Marshall's Laser Refractive Keratectomy: A Technique for Laser Refractive Surgery (Photorefra
ctive keratectomy: a technique for l
asser refractive surgery) ", J. Am. Catalog
Refract. Surg. It is defined by a motorized iris diaphragm (myopia and hyperopia) and a motorized slit (astigmatism) configured according to a profile (contour shape) derived by Volume 14, pp. 46-52 (1988)). In more detail with reference to FIG. 1, the excimer broad beam laser beam 10 typically has a rectangular shape in the untreated state with dimensions of 8-10 mm × 20-25 mm, depending on the optical system 7-10 mm. It is arranged in a square or circular shape. This excimer broad beam laser beam 10 is a motorized mechanical iris diaphragm 1
2 to produce a two-dimensional (2D) circular ablation pattern for treating myopia and a 2D rectangular ablation pattern for treating astigmatism that is projected on a motorized mechanical slit 14. , Cooperate to form the combined 2D pattern 16. Thus, the large rectangular laser beam is shaped to form a circle or smaller rectangle. These shapes are then projected under control of the cornea 20 of the eye 22 using the imaging lens 18 for refractive correction. In order to achieve refractive correction, a precisely shaped mass of tissue must be removed. Referring to FIG. 2, this tissue mass is controlled by a iris diaphragm and / or slit so as to cause three-dimensional (volume) etching, and continuous laser pulses (1, 2, 3, 3) are generated.
,, n) is removed. This is the most popular method in the commercial market today and is currently used by VISX and Summit. Referring to FIG. 3, the mechanical iris diaphragm is used to create the "circular" portion of the ablation pattern, so the etching action is not perfectly circular. The physical iris diaphragm has a finite number of wings. For example, VISX uses a 12 (12 blade) iris diaphragm, while Summit uses a 14 (14 blade) iris diaphragm. Therefore, the ablation pattern through the iris (Fig. 3
) Resolution is far from ideal (Fig. 4). In addition, selection of ablation pattern (circular,
Rectangular shapes or combinations thereof are limited by mechanical limits.

A newer approach to laser keratectomy uses a scanning laser spot system, in which a small laser spot (typically
A diameter of 0.5 mm to 1.0 mm) is scanned across the cornea in a predetermined pattern to provide refractive correction. These systems differ in that they are more flexible than the broad beam approach. By controlling a small spot, the shape of different regions of the cornea can be formed independently of other regions.
The scanning spot system uses a smaller area of the cornea (0.5 mm spot size).
To 1.0 mm), which has the additional advantage that it can be instructed to ablate more complex (as opposed to the broad beam approach) and individualized patterns. .

Recently, topographic maps of the cornea have been used to reveal that the cornea has microscopic deformations throughout it. The broad-beam laser approach ablates an equal amount of tissue from both high and low positions on the corneal surface, thus preserving the original contour of the surface. Compare Figure 5a and Figure 5b shown). Broad beam lasers cannot correct these microscopic deformations. The original scanning spot system was also unable to accommodate the surface contour shape. However, the introduction of scanning spot lasers now allows for a more controlled treatment, and thus topographic treatment of the cornea. In this method, the surface topography of the eye is considered along with the refractive correction profile. Thus, Mun
The Nerlyn equation or any other higher order model is combined with the surface topography of the eye to provide better refractive correction. To derive the ablation profile, the corneal profile (topographic data) is first determined from the corneal topograph system measurement results, as shown in Figure 6a. The topographical data is then compared to the ideal corneal shape in the uncorrected state, eg spherical or aspherical. Next, referring to FIG. 6b, the difference between the two is determined for each x, y position of the corneal topograph data array (digitized image). Next, a profile is created that removes the topographical data (peaks and valleys), leaving an ideal surface, after which a refractive ablation profile is applied. Alternatively, the topographical differences can be incorporated into the refractive ablation profile and the entire combined profile applied at one time. For both methods, the scanning spot approach allows treatment in isolated areas (as opposed to broad beams), and thus a predetermined pattern of spots is applied to try to match the topography exactly. It

The corneal topographic approach only compensates for topographic aberrations at the corneal surface. However, the eye is a complex optical system and the cornea is only one component of it. Therefore, the current refractive correction equation, such as that derived by Munnerlyn, shows what correction must be made to the shape of the cornea in order to achieve an optimal correction for the overall aberrations of the optical system of the eye. I can't propose.

There are already some new approaches to the above problems. First, coma (third order) and spherical aberration (fourth order) can be reduced by extending the mathematical equations for refraction correction to include higher order effects. C. E. Marti
nez, R.N. A. Applegate, H.M. C. Howland, S .; D. Kl
yce, M.Y. B. McDonald and J.M. P. Medina's Change in Corneal Aberration Structure after Laser Refractive Keratectomy (Change in Corneal)
Aberration structure after photorefr
active keratectomy) ", Invest. Ophthal
mol. Visual Sci. Suppl. , 37, 933 (
1996). Second, by improving the simplified models of the eye to include higher-order aberrations, these new models provide insight into how the various elements of the eye's optics correlate and affect visual function. Will be able to give. For example, there is general consensus that the negative asphericity of the normal cornea contributes to the negative aberration content. Negative aberration is due to the nature of the refractive index gradient of the lens,
It is compensated by the contribution of positive aberrations. H. Liou and N.N. A. Brennan
"A anatomically accurate finite model of the eye for optical modeling (Anatom).
icardly accurate, fine model eye fo
r optical modeling), J. Opt. Soc. Am
． A. 14: 1684-1695 (1997).
Centralizing work with more accurate mathematical descriptions for refractive correction in modeling human optics is an advanced ablation profile that treats the cornea as the first aspherical element in the optics. Led to the development of the algorithm. J. Sch
Wiegerling and R.W. W. Snyder's "Custom Laser Corrective Keratectomy Ablation for Spherical and Cylindrical Refraction Errors and Higher Order Aberrations"
m photorefractive keratectomy ablati
ons for the correction of spherical
and cylindrical refractory error and
"higher-order abnormality)", J. Opt. S
oc. Am. 15: No. 9, pp. 2572-2579 (1998)
Please refer to.

Therefore, more recently, several wavefront detection systems have been developed for the scanning spot laser refractive correction market. In these wavefront detection systems, one or more visible laser beams are directed towards the entire optical system of the eye, namely the cornea, lens, vitreous and retina. Return reflections from the retina are recorded by a CCD camera and analyzed against an ideal wavefront. Thus, the entire optical system is analyzed. The results of this analysis allow a simulation of the patient's best visual acuity. This data can be used to make a precise contouring of the cornea. Regardless of which technique is used, the result gives height information from the current corneal shape to the shape calculated by the scanning spot to best improve visual acuity. It becomes the contour shape topograph map.

However, all scanning spot systems have some problems. The first is the problem of treatment time. Scanning spot systems require longer refractive surgery times. Scanning spots are a time consuming approach, as small laser spots have to be moved over large surfaces (up to 10 mm for hyperopia). Scanning spot systems typically provide hundreds of spots per treatment layer, resulting in relatively long treatment times. The broad beam approach is much faster as the entire cornea is treated with each laser pulse, ie treatment layer by treatment.

The second problem is safety. Broad-beam lasers are inherently safe in terms of treatment interruption, as the cornea is treated symmetrically for each pulse. That is, since the iris describes a circle and the slit describes a rectangle, all points on the cornea being treated are treated in the same way with each laser pulse.
Even if the procedure is interrupted, there is always an almost symmetrical spherical correction, so that correction can be continued more easily later. However, a scanning spot with a small spot size cannot cover the entire corneal surface with one laser pulse. Therefore, when an interruption occurs, there is no guarantee that the corneal etch for that layer is complete at the interruption location. It is difficult to continue at the interruption position.

Third is the issue of tracking. Scanning spot systems require very careful tracking of the eye (target) in order to direct the spot to a precise point on the cornea when the eye moves. This means that a larger area of the cornea is treated with each pulse,
The problem with broad beams is not the same.

Fourth is the problem of surface roughness. Because the laser spot is moved in a raster scan (left to right, top to bottom) across the cornea, the scanning spot method requires overlapping laser spots due to the circular cross-sectional shape of the laser spots. (See FIG. 7). It is necessary to overlap some of the spots to provide full coverage for a given ablation zone (typical 80/20 overlap is shown in FIG. 7).
However, the overlap region is ablated at twice the etch depth per pulse. This tends to cause irregularities on the obtained etched surface. The size of the ablated volume depends on the spot overlap and, to a lesser extent, the ratio of the spot diameter to the ablation zone diameter. This problem is not seen with the broad beam approach.

The fifth is the problem of resolution. The laser spot typically has a diameter of between 0.5 mm and 1 mm. However, corneal topograph and wavefront sensor analysis provide detailed information about the correction needed for the cornea, such details may require ablation ablation at a resolution greater than 0.5 mm. . For example, referring to FIG. 8a, both the corneal topograph and the wavefront sensor analysis provide images that define multiple topograph areas that require ablation.
One such topographical area is isolated in Figure 8b. However, referring to FIGS. 8c and 8d, neither the 1 mm diameter spot nor the 0.5 mm spot is sized to ablate (ablate) the topographical area with the desired resolution.

In response to problems associated with current broad beam and scanning spot systems, Freeman US Pat. No. 5,6, which is hereby incorporated by reference in its entirety.
No. 24,437 discloses the use of a digital micro-mirror device (DMD) to redirect broad beam laser pulses. The DMD contains over one million individually settable mirrors, each mirror having a 13 μm or 16 μm square reflective surface per side. The mirror can be configured to a very high resolution refractive correction pattern, and the laser energy is reflected by the mirror into the correct correction pattern in the eye. While the above system does not have any of the disadvantages associated with conventional broad beam and scanning spot systems, it does offer each.

Given the superior resolution possible with the Freeman DMD laser system, a DM that can be configured to perform any type of laser ablation pattern.
It is desirable to utilize the D laser system. Laser ablation patterns include broad beam circular and rectangular patterns, scanning spot circular and rectangular patterns, corneal topograph patterns, and wavefront sensor analysis patterns.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a DMD refractive correction laser system capable of reproducing with high resolution any ablation pattern currently used in broad beam systems and spot scanning systems. To do.

Another object of the present invention is to set a DMD mirror configuration to a refractive correction pattern.
It is to provide a control system for a refractive laser system.

Another object of the invention is to allow the DMD to be utilized in current broad-beam lasers, and to make such lasers visible at higher resolution, speed and accuracy. It is an object of the present invention to provide a control system that enables refraction correction of an optical system.

An additional object of the invention is to provide a control system for a DMD refractive correction laser system that can be operated in broad beam mode or scanning spot mode.

According to these objects, a laser eye surgery system according to the present invention comprises a laser for producing a laser beam capable of refractive correction, an optical system for adjusting the shape and condition of the laser beam, and a shape. And a DMD for reflecting the conditioned beam towards the eye, a computer system for controlling the mirror of the DMD, and an eye tracking system for tracking the eye position and providing feedback to the computer system. Equipped with. In accordance with the present invention, a computer system allows system software to emulate (i.e., mimic) a pattern and laser beam control provided in prior art broad beam and scanning spot systems with a DMD. It is equipped with clothing. With the above in mind, the laser surgery system is applicable to perform all approaches currently used for laser surgery. That is, since these techniques are controlled by the software of a computer system coupled to the DMD, the surgical system is not limited by hardware requirements,
The software configuration allows a single laser surgery system to be used to perform surgery according to any desired approach described above. Further, the laser surgery system is coupled to or configured to receive data from the corneal topographer or wavefront sensor system, which data can be utilized to improve the quality of correction. The size of each DMD mirror is 13
Since it is μm or 16 μm, which is considerably smaller than the smallest scanning spot, the laser surgery system offers significantly higher resolution than prior art systems.

Additional objects and advantages of the present invention will be apparent to those of ordinary skill in the art by reference to the detailed description made in connection with the provided drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 9, a laser eye surgery system 100 includes a laser 102 for producing a laser beam capable of refractive correction, and the shape and condition of the laser beam. Optical system 104 for adjusting the beam and a digital micromirror device (DMD) for reflecting the shaped and shaped beam towards the eye 108.
106 and a computer system 110 for controlling the mirror of the DMD 106,
An eye tracking system 112 that tracks the position of the eye 108 and provides feedback to the computer system 110. With the exception of the eye tracking system 112, which is dealt with in more detail below, the laser surgical system 100 is disclosed in the specification of US Pat. No. 5,624,437 already referenced as an integral part of this application. It is similar to the laser beam modulator.

More specifically, computer system 110 includes a computer 114 that includes a microprocessor, a video controller board 116, and a DMD controller 118 that can individually operate the mirrors of DMD 106 to either an on or off position.
And a video monitor 120. The computer system 110 can control the video controller board 116, monitor and control external devices (safety switch, operating foot switch, shutter, laser interface, etc.) and provide information to the user. The presently preferred computer 114 is a Dell with two 550 MHz Pentium III Xeon processors, 128 MB RAM, and a 9.1 GB SCSI hard disk drive.
It is a Workstation Model 6550, but other computers can be used as well. Video controller board 116, eg Ins
An LCD 555 PCI video card (P / N 710920), commercially available from IDE Technology, supplies video signals to the DMD controller 118 as well as the video monitor 120. The DMD controller 118 is a video receiving card, preferably T, which receives video information from the video control board 116.
XGA video reception control card from exas Instruments (
P / N 4186152-0001) and a video driver card that converts the video information into a signal that drives a suitable mirror of the DMD 106 to turn it on or off, preferably a Texas Instruments XGA video driver card (P / N).
N4186137-0001). The DMD controller 118 may be provided outside the computer 114, or may be provided as a card or a card set inside the computer.

The optical system 104 is provided between the laser 102 and the DMD 106, and preferably shapes the laser beam (this may be beam expansion, collimation,
(Which may include homogenization), directs the laser beam to the DMD 106 for pattern control, and consists of commercially available common optical components used to direct the laser beam from the DMD to the corneal surface of the eye. ing. Such optical systems are well known to those of ordinary skill in the art. DMD106 is Texas Instrument
UV rays for excimer-based refractive surgery system (commercially available from ents
A UV) transmission window or an infrared (IR) transmission window for longer wavelength refractive surgery systems is provided.

In accordance with the present invention, computer system 100 is provided with software that generally controls the operation of the laser surgery system. The software receives (a) input from refraction test results that define the type (myopia, hyperopia or astigmatism) and degree of correction required and (b) generates an appropriate refraction correction profile (contour shape). , (C
) Generate an ablation pattern for each laser pulse, and (d)
Convert to DMD control data for each layer requiring correction, (e) start procedure, (f) track eye (target) position, feed back eye position to DMD controller, (g) Check system parameters and fire laser when ready. The software is developed in Lab View®, but any suitable language (eg, C, C ++, etc.) can be used for software development.

As described in detail below, the ablation pattern is a high resolution emulation of a current mechanically generated broad beam pattern, scanning spot pattern, corneal topograph pattern or wavefront sensor analysis pattern. ) Can be accommodated. The ablation pattern is provided by the computer 114 to the DMD controller 118, which causes the DMD mirror to direct the laser beam toward the surface of the cornea according to the pattern. In addition, each ablation pattern is software and D
Since it relies solely on MD, the laser surgery system emulates either a broad beam pattern, a scanning spot pattern, a corneal topograph pattern or a wavefront sensor analysis pattern on demand, depending on the data input required. It is preferable that it is configured as follows.

Thus, multiple physicians can use a single laser surgery system,
Each physician may desire to use a different one of the broad beam approach, the basic spot scanning approach, the corneal topography approach and the wavefront sensor analysis approach. All that is required to operate under the chosen approach is to instruct the software to control the computer system,
It just operates the laser surgery system accordingly.

Broad Beam Approach By selecting the broad beam approach mode of operation, the DMD mirror can be configured by the computer 104 and the DMD controller 118 into any broad beam pattern. In addition, DMDs with 13 μm or 16 μm square mirrors have considerably higher resolution, producing nearly perfect circles when the image focus in the eye is slightly blurred. The DMD is either a circular pattern (FIG. 10) or a previously used circular pattern that corresponds to the mechanical iris diaphragm (FIG. 3) that was previously used by turning on the appropriate mirrors to produce a pattern of the correct size. A rectangular pattern (FIG. 11) corresponding to the existing slits can be generated. In Figures 10 and 11, only 256 of the millions of DMD mirrors are shown.

In more detail with reference to FIG. 12, the refractive correction of the eye is diagnostically recorded,
At step 200, the values associated therewith are entered into the system as spectacle values or corneal surface values. The software allows registration of values in both forms, and if the registration is spectacle values, the value was based on the distance between the spectacle surface and the corneal surface (typically 12.5 mm). It is converted into a corneal surface value by a look-up table.

In step 202, whether spherical correction (for treatment of myopia or hyperopia) or cylindrical correction (for treatment of astigmatism) or both is required based on the refraction value from the diagnosis of step 200. Is determined. For spherical correction, in step 204, a multi-zone multi-stroke (MZMP) algorithm (where each zone is corrected separately) is performed on the lens equations to more closely approximate the asphericity of the cornea. Preferably. Alternatively, the multi-zone single-stroke (MZSP) algorithm may be performed by the selection in step 252, as described below. One preferred lens equation is a variation of the Munnerlyn linear equation described below. However, it is also possible to perform higher order profiles for all the refractive correction profiles discussed below. Depending on the refractive correction, a certain number of optical zones are selected for correction. Referring to FIG. 13, these areas are 2.5 mm in diameter, 4.0 mm, 5.0 mm, 6.0 mm and 7.0 mm in size and centered on the optical axis of the laser beam. The 2.5 mm and 7.0 mm areas are always selected and are respectively the pretreatment areas (pretreat).
ment zone, called the blend zone. 2.
The 5 mm pretreatment area is designated by reference numeral 260 and is present to reduce or eliminate the central island problem, ie, the central flat portion of the cornea. The 7.0 mm harmony zone, indicated by reference numeral 268, is present to reduce abrupt tissue changes between the correction area and the surrounding corneal stroma. Other areas are expanded capacity areas (po
wer zone) and is used to provide most of the refractive correction. The expansion area 1 has a diameter of 4.0 mm and is designated by the reference numeral 262,
The expansion area 2 has a diameter of 5.0 mm and is indicated by reference numeral 264, and the expansion area 3 has a diameter of 6.0 mm and is indicated by reference numeral 266. For cylindrical correction (astigmatism), only a single power area (typically 5 mm in diameter) is used to apply the spherical removal volume to the cornea.

[0033]

[Table 1]

Table 1 lists the optical zones (OZ) used and the percentage of spherical and cylindrical correction in the refractive correction performed on each optical zone. 2.
For the 5 mm area and the 7.0 mm area, the ratios listed are for the modified Mu
It is the preferred ratio of refractive correction for eye correction based on the nnerlyn equation. Expandable area within each level of correction (ie 4.0 mm area, 5.0 mm area, 6.0
mm area), the percentages for all of the power areas add up to 100 percent, and each one has its own preferred refractive correction ratio in the cornea, as inserted in the modified Munnerlyn equation described below. Has become. In particular, for straightening less than 3.0 diopters (D), 100 percent straightening is applied to the 6.0 mm area. For corrections from 3.0D to 6.0D, 60% of the refractive correction is in the 5.0 mm area and 40% of the correction is 6.0%.
It is performed in the 0 mm area. For straightening greater than 6.0D, 50 percent of the straightening is in the 4.0 mm area, 30 percent is in the 5.0 mm area, and 20 percent of the straightening is in the 6.0 mm area.

For each optical zone requiring correction, the desired depth at a particular radius from the optical axis to the outer diameter end of the optical zone can be determined according to the following variant of the Munnerlyn equation.

[Equation 1] Where Z _abl (r) is the ablation depth of each laser pulse at a given radius r (a known value for a given laser system), R _pre is the radius of curvature before surgery (based on average) ) Is assumed to be 7.86 mm, D is the optical area in millimeters, corresponding to many of the areas listed in Table 1, and n
Is the refractive index of the cornea (1.3771), and f is the degree of the lens defined by the surgeon (magnification of the lens), which is the refractive correction to be performed for a given area (
That is, the percentage value obtained from Table 1 for a particular optical zone is used as f).

Needed to complete the procedure by knowing the ablation (ablation) etch depth per laser pulse, Z _abl (r), known as the etch depth per pulse, or EDPP, at a particular radius. The number of pulses to be taken is determined. This determination is made by determining the maximum ablation depth at the center of the optical zone (radius r = 0.0 mm) and dividing by EDPP. That is, the number of laser pulses required for correction (NLP) = Z _abl (r) / EDPP.
In order to actually perform laser ablation, the "iris diaphragm" radius for each laser pulse must be known. For example, each value is given to the equation from the center of the optical area where r = 0.0 mm and etching depth = maximum (mm) to the maximum optical area where ablation depth = 0.0 mm, and calculated as described above. The equation is solved for the radius r of each laser pulse (NLP) required to complete the determined procedure. However, Munnerlyn's modified formula cannot be solved in a deterministic form, so that iterative solutions are used, for example those using the zero finder algorithm such as those of Zbrent and Ridder. In step 206, from above (ie, when the radius r is known), the “iris diaphragm” size (ie, the size of the circular pattern) used to correct the associated optical zone is determined. This process is repeated for each area that must be corrected, and for each laser pulse required, the associated "iris diaphragm" size is calculated. An example of a printed myopia treatment screen is shown in FIG. 14, where reference numeral 207 is the required spherical correction and reference numeral 208 is the correction value for performing the correction. Reference number 209
Indicates the MZMP value.

The hyperopia treatment profile is also determined in steps 204 and 206 in much the same way. However, at the lateral edge of the cornea, ie ((
The tissue must be removed in the shape of a ring-shaped pattern with a diameter of 5 mm to 10 mm around the optical axis of the laser beam (so that the cornea becomes steep). The equation must be used. Others of the Munnerlyn equation (Charles
Munnerlyn, Steven Koons and John Marshall
L. Laser Refractive Keratectomy: Method of Laser Refractive Surgery (A Techn
`` for for Laser Refractive Surgery) '',
J. Catalog Refact. Surg. , Volume 14, 1988 1
In the month), the tissue removal depth for hyperopia correction at the distance r from the optical axis is given by the following formula.

[Equation 2] Where Z _abl '(r) is the hyperopic ablation depth of each laser pulse at a given radius r (a known value for a given laser system), R _pre is the _pre- operative radius of curvature, ( 7.86 mm (based on the mean), n is the refractive index of the cornea (1.3771), and f is the positive lens power (hyperopia) defined by the surgeon, typically Is a refractive correction to be performed on an area of 5 to 10 mm.

By knowing the ablation EDPP and determining the center r _{cent of the} hyperopic zone (end radius minus start radius divided by 2), the number of pulses required to complete the procedure is determined. It is determined. This determination is made by taking the maximum depth of ablation that occurs at r _cent and dividing by EDPP. That is, the number of laser pulses required for correction (NLP) = Z _abl (r _cent ) / EDPP. Next, in the same way as described above for myopia correction,
The radius value of each profile is determined. Note that no ablation of tissue occurs in the optical axis, producing a ring-shaped profile similar to that shown in FIG. 15, but with a larger scale profile.

Ablation by this type of ablation cannot be achieved using the prior art combination of iris diaphragm and slit. Rather, the prior art is
It requires the use of a mask or directing the image of the iris diaphragm / slit aperture towards the outer region of the cornea. Both of these methods are difficult to implement. However, referring to FIG. 15, it is clear that the DMD can implement a ring-shaped pattern as easily as any other pattern. Therefore, when treating hyperopia, data corresponding to the size of the ring-shaped pattern for each area requiring correction is calculated.

Radius values for cylindrical correction (astigmatism) are determined in steps 204 and 206.
Almost the same as the spherical correction (myopia) of Step 212 and Step 21.
Determined in 4. 100% of the refraction correction is in one optical zone (
Typically, the column of cylinders in Table 1 is used, which indicates that it is done at 5 mm). An example of a printed astigmatism treatment screen is shown in FIG. 16, in which reference numeral 215 indicates the required cylindrical correction and reference numeral 216 indicates the cylindrical correction for performing the correction. The value is indicated by reference numeral 217, which is the MZMP value.

For certain eyes, a combination of spherical and cylindrical correction may be required. Thus, once the size of the "iris diaphragm", "slit" and ring-shaped pattern has been calculated for that particular eye, the respective data relating to the size and shape of the correction, at step 218, for the particular optical zone. It is integrated as one continuous data array that represents the refractive correction order of the cornea. For example, it may be desirable to perform overall astigmatism correction prior to any myopia or hyperopia correction. In such a case, the astigmatism correction data is arranged first, and the myopia or hyperopia correction data is arranged at the rear position. Alternatively, the astigmatism correction data array and the hyperopia or myopia correction array may be arranged so as to be sandwiched between each other. Regardless, the corrective data is preferably incorporated into the data array in association with the order in which the corrective laser ablation pattern is applied to the cornea.

In steps 220 to 224, an image is generated representing the desired laser beam ablation profile in each layer of the cornea based on the data array and the order of the data array. More particularly, in step 220, for each ablation layer requiring spherical correction, a software iris diaphragm subroutine is used to emulate a prior art mechanical iris diaphragm or ring-shaped pattern image of 1 bit. Alternatively, a two-color multi-pixel image (pixel map (Pixmap)) is generated. Such images are similar to those shown in Figures 10 and 15, but vary in size depending on the amount of correction and the area to be corrected. In step 222, for each ablation layer requiring cylindrical correction, a software cylinder subroutine is used to generate a 1-bit pixel map that emulates the image of a prior art rectangular mechanical slit pattern. Such an image is similar to that shown in Figure 11, but varies in size depending on the amount of correction and the area to be corrected. After the rectangular pattern is generated, in step 224 the software Cylinder Angle subroutine is used to rotate the Cylinder Pixel Map to the required correction axis angle. Preferably, in step 226, the subroutines 220, 222, 2
The results from 24 are combined into a single pixelmap image file for each ablation layer containing image data for each laser pulse at each step.

Once the pixelmap image is generated, the actual laser surgery can begin. In general, the patient is placed under the microscope and precisely positioned for the procedure, and the physician prepares the patient in step 228. The preparatory measures include
Laser Refractive Keratectomy (PRK) or Laser Keratoplasty (LASIK)
Including using itself. That is, in either method, the corneal stroma must be exposed in order to apply the laser beam to the cornea for corneal reshaping. In PRK, the corneal epithelial tissue (about 40-55 μm) is any effective means,
Removed to expose the endothelium, for example by laser, scraping, or chemical means. In LASIK, a tissue flap is incised into the corneal stroma to a depth of about 120-160 μm and the flap is turned over to expose the corneal stroma. The physician then reviews the therapeutic profile and begins the surgical procedure.

Next, the software converts (translates) the pick cell map into DMD mirror position data.
To do. At step 230, the individual mirrors of the DMD are respectively associated with on or off positions so that the DMD receives the data and the array of mirrors forms a pattern that mimics a pixelmap image. As mentioned above, when the pattern produced by the mirror is slightly defocused on the cornea, the pattern will be of very high resolution, significantly higher than that defined by prior art mechanical devices. Become.

At the same time, the software displays the pixel map image as a two-color image, ie, a black and white image, on the video monitor in step 232 to allow the physician to reconfirm and monitor the ablation pattern. There is.

The eye tracking system 112 provides an input to the computer 110, which in step 234, causes the computer 110 to further deviate from the center of the eye (or deviate from a conventional stored decentered position). Instruct the DMD controller 118 to compensate. In step 236, feedback from the eye tracking system causes the pixel map to move on the video monitor,
At 38, the mirror on / off pattern is also moved to compensate for eye movement so that the DMD mirror ablation pattern is always accurately directed toward the cornea. Various systems may be used to track eye movements and provide feedback to computer 110 and DMD controller 118. U.S. patent application Ser. No. 09, filed August 10, and referenced in its entirety as an integral part of this application.
One approach disclosed in US Pat. No. 3,371,195 is an eye tracking system 1
12 uses a CCD camera connected to a surgical microscope, an illuminator that illuminates the eyes, and an algorithm that finds the center of the pupil and compares it to the starting point of the procedure. In order to offset the refractive correction pattern produced by the mirrors of the DMD 106 so that the refractive correction pattern is directed to the correct location based on the last position of the eye, the eye tracking system 112 directs the computer 110 to do so. It is possible to continuously send eye movement information. Other approaches for tracking the target may also be used. For example, but not by way of limitation, a target label (having reflectivity or absorption for a given wavelength) placed on the cornea may be monitored, the cornea aimed and the camera or The laser spot (typically infrared energy) monitored by other electronic means (eg square detector) may be tracked,
Anterior physiological structures such as the limbus may be tracked and the retina may be tracked.

The computer system operates in parallel with all of the system parameters (including but not limited to laser status, safety switch status, gas cabinet sensor status (gas-based laser Case), status of safety shutter subsystem, status of laser energy sensor, status of nitrogen flow, status of surgeon's foot switch, status of emergency stop switch, status of surgeon joystick control, status of exhaust plume tube. , Including status indicators). Once the computer system confirms that all checks have been performed, the surgeon can fire a laser pulse (typically by operating a footswitch).

In step 240, when the laser 102 is fired, the laser 102 is tuned in shape and condition by the optical system 104 and directed toward the DMD mirror array. Next, in step 242, the laser beam is reflected by the mirror array. Each mirror reflects a relevant portion of the laser beam pulse away from or towards the cornea according to the on or off position of the respective mirror. Thus
The desired ablation pattern is reflected towards the eye. Next, in step 244, additional optics image the laser beam shaped into the predetermined pattern into the eye, preferably at a reduced ratio.

This procedure continues for subsequent ablation layers until, in steps 230 and 232, all layers (pulses) have been delivered for a given optical zone to be corrected. Further, in the MZMP method, the correction required for the other areas is provided by each subsequent "stroke" (ie the associated stroke), preferably with a slight pause between each stroke for eye examination. Each laser pulse on the DMD mirror pattern)
In the patient's cornea.

In the resulting step 250, the etching performed is aspheric in shape and is represented by the graph of FIG. In FIG. 17, the ablation for individual areas is thin (2.5 mm pretreatment area 260, 4 mm power area 262, 5 mm power area 264, 6 mm power area 264). Is indicated by reference numeral 266 and the 7 mm matching area is indicated by reference numeral 268), while the overall ablation resulting from the combination of the individual areas is indicated by the bold line at reference numeral 270.

The above describes the MZMP approach for broad-beam emulation, which defines a pixel map for DMD pattern generation to ablate across multiple areas at each step. You can also do it. Therefore, in step 252 of FIG. 12, in the multi-zone single stroke (MZSP
) You can choose the approach. Choosing the MZSP approach merges the spherical and cylindrical position data arrays for each zone into a single array that represents the combined treatment zone profiles. By calculating the sum, according to one way of implementing the MZSP approach, all areas and their profiles are merged into the graph curve 270 of FIG. However, the curve 270 of the graph has a plurality of transition points 272a, 272b, 272c, which are preferably removed (ie, smoothed). These transition points are not as severe as those created using conventional iris diaphragms and slits in the broad beam approach. Nevertheless, any transition point may make the corrected eye susceptible to glare or lump effects.

Thus, for the MZSP approach, the result is a curve associated with the graph curve 270 that provides a very smooth ablation profile with no transition points, such as those shown in FIGS. 26a and 26b. Is desirable. This provides a second way to implement the MZSP approach. In this scheme, a dynamic polynomial simulates a multi-zone profile, but is determined solely on the basis of diopters. Dynamic polynomials are determined by first classifying the required corrections according to their severity. In the multi-zone method, for more severe corrections than -6 diopters, five zones (including pretreatment zone and harmony zone) are used,
For corrections between 3 and -6 diopters, 4 areas are used, and for corrections less than -3 diopters, 3 areas are used. Referring to FIG. 27,
For each of the three classes of orthodontic severity, several profiles are generated that cover the full range of that class. Next, a graph is created that edits (compiles) the data into a format that can be transformed to define a trend line. This is Mic
soft Excel (registered trademark) or National Instrument
It is performed by any of several software packages such as ents Hi-Q ™. Third, as shown in FIG. 28, a trend line is defined for each profile. The trend line equation (shown in Figure 28) must closely follow the contour shown in Figure 28. A curve-fitting (fitting) polynomial is preferably used for the trend line, but other curve-fitting equations, such as the error function erf (r), can also be used. It has been found that a 6th order polynomial produces exactly the required profile. Each equation represents a profile of a particular correction (diopter) and is divided into smaller terms. It was found that the magnitudes of the order elements of each formula are graphed based on the degree of correction, and the magnitudes of the order elements of each formula are almost linear, as shown in FIG. (R ₂ = 0.9999)
. Further, as also shown in FIG. 29, the second polynomial is generated based on the trend line. One such quadratic polynomial y = 0.0015x ² + 0.0505x
+0.0561 is shown in Figure 29 and provides the desired fitted curve. This second
The software is written to generate a dynamic equation that produces a smooth profile based on the desired diopter correction from the polynomial of . This software can be applied to a DMD in which the central mirror element of the DMD is selected and the radial distance value of each other mirror element to that central mirror element is determined. Then all values are represented as a numerical array as a data file, and the procedure is performed in the same way as the MZSP approach described above, with a smooth 3D cut image along the length, ie without transition points. (Fig. 26a) and 2D ablation profile (Fig. 2
6b) is generated.

Further, although spherical and cylindrical data arrays have been used to generate pixelmap images, the signals used to control the motors for the iris diaphragm and slits are directly utilized. It can also be converted into pixel map image data. Thus, the DMD-based broad-beam approach is very versatile and the physician-based configuration is not subject to the mechanical limitations of the prior art.

Scanning Spot Approach By selecting the scanning spot mode of operation, more complex special ablation patterns can be applied to the cornea. Circular (for spherical myopia or hyperopia) or rectangular (for astigmatism) ablation patterns can be applied to the eye in MZMP or MZSP format by combining the Munnerlyn approach with the “iris diaphragm” and “slit” patterns described above. To be done. Referring again to FIG. 7, the most widely used scanning technique for effecting spot scanning according to the ablation pattern is raster scanning, which closely resembles the scanning (left to right, top to bottom) of television monitors. FIG. 18 shows another scanning method used at present, which is called random scanning, in which the laser spot is moved around the cornea in a random order. This scanning method reduces potentially harmful heating effects due to the spots being applied very close to each other. FIG. 19 shows a novel method according to the invention called polar scanning. In polar scanning, the spot is scanned circularly in each pulse layer. Each spot is preferably moved in a 50/50 overlap, although other proportions of overlap can be used. This approach will match the edges of the circle more than the raster approach. In addition, FIG. 20 shows a new method of rotation (here shown at 20 °,
Other rotation angles may also be used). Therefore,
A plurality of fan-shaped portions (sectors) are continuously scanned. FIG. 21 shows yet another new approach, the close packing method, which uses a hexagonal approach to cover the area more efficiently. With the closest packing, there is no overlap of laser spots. In any of these methods, the spot overlap can be tailored to optimize the resulting etching profile, and the scan can be center-to-outside or perimeter-to-inside. .

Among the scanning spot methods (raster, random, polar direction, close packing, and other unexplained methods) used by the DMD in corrective eye patterns and conventional scanning spot approaches, depending on the software. Any one can be emulated in either of two modes.

In the first mode (spot mode), enough mirrors (eg 30 × 30 to 6
With a 0x60 mirror array turned on, a typical scanning spot laser diameter (eg,
The scanning spot approach can be emulated by generating 0.5 mm to 1.0 mm). Alternatively, a smaller number of mirrors can be turned on so that the "spot" is much smaller than a typical scanned spot, and a reasonably good resolution can be obtained. This "spot" can then be turned on or off by turning on or off the appropriate mirror to emulate spot offset or scan across the DMD device, eg, raster, random, polar, The entire cornea is moved in the polar direction with rotation and the closest packing).

In a second, more preferred mode (Layer Mode), the software directs the DMD to turn on the appropriate mirror and after all scanning spots have been sent in spot mode to the particular ablation layer. A single laser pulse performs the ablation of the entire layer by turning on the appropriate mirrors to emulate the final etch pattern produced. In this way, the entire layer is ablated at one time, eliminating the concerns shown regarding the effects of interruptions of conventional scanning spot systems.

In more detail with reference to FIG. 22, the scanning spot emulation method is initially similar to the broad beam approach. That is, in step 300, a clinical refraction test is performed to determine the degree of correction required. Next, in step 302, the spherical correction is determined and in step 304 the lens equation (first or higher order) is used to generate a spherical correction profile. Similarly, in step 310, a cylindrical correction is determined and in step 312 the lens equation is used to generate a cylindrical correction profile.

In step 314, the spherical correction profile and the cylindrical correction profile are combined to obtain an initial correction. Although not required, scanning spot emulation preferably additionally occupies part of the corneal topograph data. Therefore, in step 316, the topography generator 130 (FIG.
), For example, a Keratron Corneal Analyzer manufactured by Optikon 2000, Inc. of Rome, Italy, is used to determine the actual corneal topograph. The topographer produces a pixel map image of corneal height data at each pixel of the image. The pixelmap image is preferably 8 bits, but other resolutions can be used. Step 31
At 8, an "ideal" topographic profile is generated based on the actual topography of the cornea. The ideal profile corresponds to the ideal spherical or aspherical fit provided by the topographer via a mathematical model. Next, in step 320, the difference between the actual profile and the ideal profile is calculated to produce a difference profile. The difference profile is a pixel map image showing the difference in height between the ideal profile and the actual profile at each pixel. Then the difference profile is combined with the initial correction profile,
Generate a final correction profile.

Next, in step 324, etch depth per pulse (EDPP)
A pixel map image for each etch slice or layer is generated from the final correction profile based on The pixelmap image for each layer is a 1-bit image, and the data associated with the series of pixelmap images corresponding to the entire laser ablation is stored in the memory of the computer system.

If the surgical system seeks to emulate a spot scanning system directly (ie, cause each laser pulse to ablate a single pixel-sized spot of a layer by ablation), at step 326 each The pixelmap image is divided into a plurality of spots having a certain proportion of overlap and spot layout (raster, random, polar orientation, closest packing, etc.) and stored as data. If moving spot emulation is desired (ie, the entire layer is ablated for each laser pulse),
No such division is desired and step 327 is performed.

At this point, the actual laser surgery procedure can begin and the patient is prepped, as described above, in step 328. Next, in step 330, a pixel map spot (when step 326 is performed) or an entire pixel map image (when step 327 is performed) that represents the initial location of the ablation is loaded into a buffer of computer system 110. It The target tracking system 112 then computes the eye movements and manipulates the buffer data so that the spot or image is translated accordingly. The pixel map data is displayed on the video monitor 120 in step 334, and D
MD mirrors are further placed in an on / off pattern in step 336 to simulate a pixelmap image. Next, in step 338, the laser is launched into the DMD mirror array.

When the laser 102 is emitted in step 338, the laser 102 is shaped and adjusted by the optical system 104 and directed toward the DMD mirror array. Next, in step 340, the laser beam is reflected by the mirror array. Each mirror reflects a relevant portion of the laser beam pulse away from or towards the cornea according to the on or off position of the respective mirror. Then, in step 342, the additional optics image the laser beam shaped into the predetermined pattern into the eye, preferably at a reduced ratio.

In step 330, the procedure proceeds to subsequent spot positions (if the system performs individual spot scan emulation in step 344) and / or until all layers have been treated in each optical zone requiring correction in step 346. Alternatively, it is continuously performed on another ablation layer (in both spot scanning mode and layer mode). In step 348, the resulting etch has a pixel-wise resolution of the pixelmap image and is adapted to correct defects on the corneal topograph. This procedure causes a resolution correction that is at least as sharp as that of prior art systems, depending on the spot size. See, for example, the scanning spot ablation patterns shown in FIGS. 8 (c) and 8 (d). Higher resolution can be obtained with a relatively small spot.

Corneal Topographic Layer Approach The corneal topograph-based scanning spot system provides good results for the broad beam approach and the conventional scanning spot approach, while the scanning spot size and spot overlap in the scanning spot approach Any scanning spot approach is constrained in that resolution is limited. The following describes a corneal topographic layer approach optimized for use with DMDs, subject to this limitation.

With reference to FIG. 23, this procedure is generally similar to the spot scanning approach described above that utilizes corneal topograph data. Therefore, steps 400 to 422 correspond exactly to steps 300 to 322 of FIG. 22 described above. According to this approach, after the final straightening profile is obtained based on the etch depth per pulse (EDPP) in step 422, the computer 110 divides the final straightening profile into layers in step 424. Each layer is converted to a 1-bit pixelmap image in step 426 and the 1-bit pixelmap image is stored as data in the memory of computer 110. At this point, the procedure continues and Step 4
28 to step 442 are just steps 328 to 342 of FIG.
Equivalent to. After the laser beam is imaged in the eye in the pattern of the treatment pixelmap image of the particular correction layer in step 442, if there are additional layers requiring treatment in step 444, the procedure proceeds to step 430. Will be continued. At step 444, if no other layers require treatment, then at step 446 the procedure is complete. As shown in FIG. 24, (13 μm or 1
This approach (using a 6 μm mirror) can better fit the corneal topograph and other correction requirements than the scanning spot system (using 0.5 mm or 1 mm spots). Note that this approach provides about 60 times the resolution of prior art scanning spot systems.

Wavefront Detection Approach Selecting the operation of the wavefront sensor mode enables the most advanced laser refraction correction system. In order to select this mode, laser surgery system 100 must be coupled to or configured to receive data from wavefront sensor system 140 (FIG. 9). The wavefront sensor system 140 analyzes the optics of the eye 108 and provides data corresponding to a three-dimensional representation of the optics of the eye. The three-dimensional result is transformed into an array of optical wavefront data that characterizes the entire optical system of the eye. This information can be in the form of topographic data (ie height values that need to be corrected to reach an optimized corneal shape) or optical magnification data (often referred to as K-reading). Preferably. One such wavefront sensor system is disclosed in US Pat. No. 5,777,719 to Williams, which uses a Hartmann-Shack sensor and is incorporated herein in its entirety. Referenced as a thing. Others are 20/10 Perfect in Heidelberg, Germany
Vision, Technomed GmbH of Baesweiler, Germany,
Bausch & Lomb Surgica, Claremont, CA
and Tracey Technologies, Inc. of Bellaire, Texas.

Here, one or more visible laser beams are directed towards the entire optical system of the eye, ie the cornea, lens, vitreous and retina. Return reflections from the retina are recorded by a CCD camera and analyzed against an ideal wavefront. Thus, the entire optical system is analyzed. According to the present invention, the results of this analysis control the etching of the cornea, rather than providing data to generate an ideal topographic profile (as done in a corneal topograph driven system) or an initial correction profile. Provides data that is used directly for

Thus, laser refractive surgery proceeds much like that described above with respect to the corneal topographic layer approach described above. The main difference lies in the form of the wavefront analysis system: offline or real-time. In the off-line approach, a series of layers is created and stored prior to surgery, as done in the corneal topographic layer approach, and then the series of layers is used to guide laser ablation to the cornea. In the real-time approach, a wavefront sensor is incorporated into the refraction correction laser system, and after each layer (or series of layers) is ablated, a corneal evaluation is performed. This continues until Fordback from the wavefront sensor indicates that the cornea has been properly modified to correct aberrations in the eye optics.

Referring to FIGS. 9 and 25, according to the wavefront sensor approach, the wavefront sensor system 140 measures the optics aberrations of the eye and determines the 3D contour profile (FIG. 8) in either the offline approach or the real-time approach. (Similar to (a)), and the corresponding data is input to the computer system 110 in step 502. Next, in step 504, the computer system creates a contour profile (3D data) into a plurality of layers (based on the EDPP).
A series of 2D data points) or sliced. In step 506, each layer is converted into a 1-bit pixelmap image and the computer system 11
No. 0 memory is stored as layer data. Next, in step 508, the surgeon prepares the patient for laser refractive surgery (PRK or LASIK). Next, in step 510, the appropriate layer data is loaded into the buffer. In step 512, the eye tracker computes eye movements and adjusts or translates the pixel map image accordingly. The translated pixel map image is displayed on the video monitor in step 514,
In step 516, the DMD 106 is provided to the DMD 106 through the DMD controller 118 to enable the DMD to simulate a pixelmap image. Step 518
At, the laser beam is directed toward the surface of the DMD mirror array and then, at step 520, is reflected by the DMD surface toward the cornea according to the pixelmap image. In step 522, the optics image the reflections in the eye, preferably in a reduced ratio. In real-time mode, in step 500, the procedure repeats the subsequent wavefront sensor analysis for the eye optics. The process is repeated until wavefront sensor analysis confirms that the eye optics have been corrected to within the preferred tolerance range. In offline mode, in step 510, the procedure continues with the loading of the next straightening layer. In either mode, in step 526, the entire eye optics is corrected to pixel-by-pixel resolution when all layers have been etched.

Each of the off-line and real-time approaches are disclosed in further detail in the specification of US patent application Ser. No. 09 / 524,312, which is incorporated by reference above.

In view of the above, there is provided a laser surgery system applicable to emulate and / or perform all currently used approaches to laser surgery. That is, since the procedure is controlled by software coupled to the DMD and not limited by hardware requirements, a single laser surgery system can be used to perform surgery by any of the approaches described above. Moreover, unlike any conventional system, the laser surgery system can fit corneal topograph or wavefront sensor data directly "point-to-point" from the data points to the individual DMD mirrors. That is, since the corneal topograph system and the wavefront sensor system are both digital in nature and provide two-dimensional digital information,
Digital information is directly mapped onto the two-dimensional array of DMD mirrors. Further, because the individual mirror dimensions of the DMD are 13 μm or 16 μm, laser surgical systems can provide significantly higher resolution than prior art surgical systems. DMD
Since it will be available with many smaller mirrors, the resolution of the techniques described herein will be increased as well.

The embodiments of the laser surgery system and the method of using the laser surgery system have been described and illustrated above. While particular embodiments of the present invention have been described, the present invention is intended to be as broad as possible and acceptable to the state of the art and as the specification is intended to be read as well. It is not intended to be limited to the above embodiment. Thus, although particular prior art systems have been described for purposes of describing emulation, it will be appreciated that other systems may be emulated. Further, while a particular type of scanning method has been disclosed, it will be appreciated that other scanning methods can be used. Also described is a laser surgery system capable of emulating a broad beam method, a corneal topograph scanning spot method, and a wavefront sensor scanning spot method, but emulating at least one of the above methods and provided by a DMD. It will be appreciated that it is also possible to provide a laser surgical system that includes the advantages of superior resolution. Therefore, a corneal topographer or wavefront sensor system is preferably included in the laser surgery system, but neither is required.
Further, while the present invention has been described with respect to the modified Munnerlyn equation, the unmodified Munnerlyn equation (in the claims, they are collectively referred to as the Mannerlyn equation) or any other lens equation , For example Schwiegerling's higher order equations can also be used. Also, multiple scanning methods have been disclosed with varying overlap, but because the DMD has a relatively high resolution and can slightly defocus in the cornea,
It should be appreciated that no overlap is required in any scan spot emulation. Moreover, although the steps of each method are preferably in a particular order (as shown in the flow chart), it should be understood that steps may be performed in other orders. Thus, one of ordinary skill in the art appreciates that other modifications can be made to the provided invention without departing from the spirit of the invention and the scope of the claims.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a prior art broad beam laser system using an iris diaphragm / slit approach.

[Fig. 2]   10 is a schematic diagram showing a conventional process of laser etching a cornea.

FIG. 3 is a schematic representation of various sized apertures that can be used to define a laser ablation pattern in the case of a prior art 12-blade mechanical iris diaphragm.

[Figure 4]   6 is a schematic diagram of an ideal iris opening for generating a laser ablation pattern.

FIG. 5a   FIG. 7 is an exaggerated view of a corneal topograph before broad-beam laser ablation.

FIG. 5b   FIG. 7 is an exaggerated view of a corneal topograph after broad-beam laser ablation.

FIG. 6a   FIG. 7 is an enlarged exaggerated cross-sectional view of the cornea showing the topographic roughness of the cornea.

FIG. 6b is an enlarged exaggerated cross-sectional view of the cornea of FIG. 6a with the area above the ideal curve excised for later refractive correction etching, but below the ideal curve. However, the lower region is not excised.

FIG. 7 illustrates raster scanning operation and spot overlap of a scanning spot laser system.

FIG. 8a   3 is a three-dimensional image defining a plurality of topographical areas requiring ablation.

FIG. 8b   Figure 8b is an image of one of the topographical areas of Figure 8a.

8c illustrates a method of scanning a 1 mm diameter spot on the topograph area of FIG. 8b.

8d illustrates a method of scanning a 0.5 mm diameter spot on the topograph area of FIG. 8b.

FIG. 9 is a schematic diagram of a DMD laser refractive surgery system utilizing the control system of the present invention.

[Figure 10]   5 is a schematic diagram of a circular DMD mirror array pattern.

FIG. 11   5 is a schematic diagram of a circular rectangular or slit DMD mirror array pattern.

FIG. 12 is a flow chart for correcting the shape of the cornea using a broad beam laser system associated with a DMD.

[Fig. 13]   6 illustrates multiple zones used in a multi-zone multi-stroke algorithm.

FIG. 14 is an example of a printed myopia treatment screen using the software of the DMD laser surgery system of the present invention.

FIG. 15   3 is a schematic view of a ring-shaped DMD mirror array pattern for correcting hyperopia.

FIG. 16 is an example of a printed astigmatism treatment screen using the software of the DMD laser surgery system of the present invention.

FIG. 17 is a print screen showing the ablation volume obtained by the multi-zone multi-stroke algorithm.

FIG. 18 illustrates a random scanning method for performing functions similar to a scanning spot laser system in the laser surgery system of the present invention.

FIG. 19   3 illustrates a polar scanning method for the DMD laser surgical system of the present invention.

FIG. 20 illustrates a polar scanning method with rotation for the DMD laser surgical system of the present invention.

FIG. 21   3 illustrates a close packing scan method for the DMD laser surgical system of the present invention.

FIG. 22 is a flow chart for emulating a scanning spot approach using a laser surgery system and a corneal topographer.

FIG. 23 is a flow chart for performing laser eye surgery with an approach that utilizes corneal topograph data and is optimized for DMD.

24 shows the etching resolution provided by the procedure described in FIG. 23 for the topographical area shown in FIG. 8b.

FIG. 25 is a flow chart for performing laser eye surgery with an approach that utilizes wavefront sensor data and is optimized for DMD.

26a shows a 3D ablation image with a preferred multi-zone single-stroke (MZSP) broad-beam approach.

FIG. 26b shows a smooth ablation profile with the preferred MZSP broad beam approach.

FIG. 27   It is a graph which shows the profile of the correction degree of each grade.

28 is a graph showing a sixth-order size tendency line following the contour shape of the profile of FIG. 27. FIG.

FIG. 29 is a graph showing the approximate linearity of a trend line for a 6th order magnitude equation for each grade based on diopter correction and a polynomial based on it.

[Procedure for Amendment] Submission for translation of Article 34 Amendment of Patent Cooperation Treaty

[Submission date] August 12, 2002 (2002.12)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Contents of correction]

[Claims]

─────────────────────────────────────────────────── ─── Continued front page    (31) Priority claim number 09 / 568,166 (32) Priority date May 9, 2000 (May 5, 2000) (33) Priority claiming countries United States (US) (31) Priority claim number 09 / 718,536 (32) Priority date November 22, 2000 (November 22, 2000) (33) Priority claiming countries United States (US) (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, C H, CN, CO, CU, CZ, DE, DK, EE, ES , FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, K R, KZ, LC, LK, LR, LS, LT, LU, LV , MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, S K, SL, TJ, TM, TR, TT, UA, UG, UZ , VN, YU, ZA, ZW (72) Inventor Freeman, Jereem.             United States, Tennessee 38119, Men             Fiss, Old Lake Pike 2024 (72) Inventor Freeman, James F.             United States, Tennessee 38119, Men             Fiss, Old Lake Pike 2068 (72) Inventor Thomas, David E.             38135, Bar, United States, Tennessee             Toretto, Fisk Road 6495 (72) Inventor Davis, Jack H.             38017, Cori, Tennessee, United States             Arville, Crosswinds Cove 1019 F term (reference) 4C026 AA02 FF58 GG06 HH02 HH06                       HH12 HH13 HH24

Claims (45)

[Claims] 1. A) means for generating smooth ablation curve profile data corresponding to the desired correction of the eye; and b) deforming a portion of the cornea of the eye into a new shape according to the profile data. A laser surgery system for transforming the cornea of the eye into a new shape, comprising: 2. c) A digital ultra-mirror having a plurality of mirrors configured to modulate the laser beam produced by the laser such that the cornea of the eye is deformed into a shape having no transition points. The laser surgery system according to claim 1, further comprising a miniature mirror device. 3. The smooth ablation curve profile data is at least 1.
The laser surgery system according to claim 1, which is based on six 6th order polynomials. 4. The laser surgery system according to claim 1, wherein the laser is a broad beam laser. 5. A) inputting eye refraction correction data to a computer; b) using the computer to generate a refraction correction profile based on at least one polynomial; c) the refraction correction profile. Generating a series of ablation pattern images, and d) converting the series of ablation pattern images into control data for setting a mirror of the digital microscopic mirror device into the shape of the ablation pattern. A method of orienting each mirror of a digital microscopic device used in an ophthalmic laser surgery system having a computer, including: 6. The method of claim 5, wherein a correction in diopters is entered into the at least one polynomial. 7. The method of claim 5, wherein the at least one polynomial is defined based on a trend line defined for each of the plurality of ranges of correction required. 8. The at least one polynomial is a 6th order equation.
The method described in. 9. The method of claim 5, wherein the ablation pattern is generated to emulate a scanning spot laser surgery system. 10. A) a computer system configured to define correction data for the eye; and b) coupled to the computer system and deforming a portion of the cornea of the eye into a new shape. A laser configured, and c) a digital ultrasound system having a plurality of mirrors configured to modulate a laser beam produced by the laser such that the shape of the cornea of the eye is deformed according to the correction data. A small mirror device, the computer system configured to modulate the laser beam and separately emulate each of a broad beam ablation pattern and a scanning spot ablation pattern according to the correction data. Laser surgery system to transform your cornea into a new shape. 11. The scanning spot ablation pattern comprises at least one of: i) one or both of a circle and a rectangle, ii) a corneal topographic pattern, iii) a wavefront analysis pattern. Laser surgery system. 12. The laser surgical system of claim 10, wherein the laser beam is modulated based on correction data derived from a lens equation. 13. The laser surgery system according to claim 12, wherein the lens equation is based on thin lens theory and paraxial optics applied to a single spherical surface. 14. The laser surgery system of claim 12, wherein the lens equation is a higher order equation. 15. A computer system configured to: a) define eye correction data and, based on the correction data, generate a series of 1-bit resolution images defining a corneal deformation profile; b. ) A digital micromirror device having a plurality of mirrors and configured to adjust the plurality of mirrors into a series of patterns corresponding to the series of 1-bit resolution images; and c) the series of patterns. A laser surgery system for transforming the cornea of the eye into a new shape, including a video display that displays. 16. The laser surgery system further comprises: d) a laser configured to direct a laser beam toward the digital micromirror device, the laser beam generated by the laser being in the series of patterns. 16. The laser surgery system according to claim 15, wherein the laser surgery system is adjusted to a shape according to and is redirected by the digital microscopic mirror device to be directed toward the eye. 17. The laser surgery system of claim 15, wherein each of the 1-bit resolution images corresponds to a particular etch depth in the cornea. 18. A) inputting refractive correction data to a computer into a computer; b) using the computer to generate a refractive correction profile; and c) a series of steps for executing the refractive correction profile. Generating an ablation pattern image of d), d) converting the series of ablation pattern images into control data for setting a mirror of the digital microscopic mirror device in the shape of the ablation pattern, and e) eye movement. A digital microscopic device for use in an ophthalmic laser surgery system having a computer, the steps of: f) offsetting the ablation pattern of the mirror based on feedback from tracked eye movements. How to determine the orientation of each mirror. 19. The method of claim 18 further comprising providing corneal topograph data to the computer, the ablation pattern image being adapted to correct a defect on the corneal topograph. The method described in. 20. The method further comprises the step of providing wavefront sensor data to the computer, the ablation pattern image being adapted to modify the cornea based on the wavefront sensor data. The method according to claim 18. 21. The method of claim 18, wherein the refractive correction profile is derived from a lens equation. 22. The method of claim 18, wherein the lens equation is based on thin lens theory and paraxial optics applied to a single spherical surface. 23. The method of claim 18, wherein the lens equation is a higher order equation. 24. A) inputting eye refractive correction data to a computer; b) using the computer to generate a refractive correction profile; and c) performing a series of steps to execute the refractive correction profile. Generating an ablation pattern image of d), and d) control data causing the series of ablation pattern images to be set in the form of the ablation pattern to emulate a scanning spot laser surgical system. A step of orienting each mirror of a digital microscopic device used in an ophthalmic laser surgery system having a computer, the method comprising: 25. The method of claim 24, further comprising: e) tracking eye movements; and f) offsetting the ablation pattern of the mirror based on feedback from the tracked eye movements. The method described. 26. The ablation pattern is less than 0.5 mm.
The method described in. 27. The method of claim 24, wherein the ablation pattern is at least one of circular and rectangular. 28. The method further comprises the step of providing corneal topograph data to the computer, the ablation pattern image being adapted to correct a defect on the corneal topograph. The method described in. 29. The method further comprises providing wavefront sensor data to the computer, the ablation pattern image being adapted to modify the cornea based on the wavefront sensor data. The method of claim 24. 30. a) placing a first laser beam spot at a first site on the cornea, and b) a second laser at a second site at a predetermined radial distance from the first site. Arranging a beam spot; and c) a third portion at a predetermined radial distance from the first portion and at a predetermined rotation angle with respect to the second portion about the first portion. Locating a third laser beam spot on the eye, and scanning the plurality of laser spots across the cornea of the eye. 31. d) a predetermined radial distance from the first portion and the first portion
The fourth portion at the position of the predetermined rotation angle with respect to the third portion with respect to the portion of
31. The method of claim 30, further comprising disposing a fourth laser beam spot at the site. 32. The second portion, the third portion, and the fourth portion,
32. The method of claim 31, wherein the method is adjacent and has an overlap. 33. The method of claim 31, wherein the second site is located around the first site. 34. Each of the disposing steps is performed so that the first portion, the second portion, the third portion and the fourth portion are located within a substantially fan-shaped region. 32. The method of claim 31. 35. The method of claim 31, wherein the first portion, the second portion, the third portion and the fourth portion are adjacent but have no overlap. . 36. a) inputting eye refraction correction data to a computer; and b) generating a spherical refraction correction profile and a cylindrical refraction correction profile from the eye refraction correction data using the computer. a computer comprising: c) generating a series of layered image data for at least one of spherical refractive correction and cylindrical refractive correction; and d) transferring the series of layered image data to a digital micromirror device. For orienting each mirror of a digital microscopic device used in an ophthalmic laser surgery system having a. 37. The method of claim 36, wherein the layered image data is generated and the layered image data is combined for each of the spherical correction and the cylindrical correction. 38. further comprising: e) inputting corneal topograph data into the computer; f) modifying at least one of the spherical refractive correction profile and the cylindrical refractive correction profile for the corneal topographic data. 37. The method of claim 36, wherein the series of layered image data is generated for a modified refractive data profile. 39. The method of claim 38, wherein the layered image data comprises corneal height information. 40. The method of claim 39, wherein the layered image data is divided into a series of 1-bit images. 41. The method of claim 40, wherein each 1-bit image corresponds to an etching depth of the laser of 1 pulse. 42. The method of claim 36, wherein the layered image data is divided into a plurality of spot size portions. 43. a) means for generating a spherical correction profile and a cylindrical correction profile; b) determining iris diaphragm size data for each of a plurality of sliced portions with the spherical correction profile; Means for determining slit size data for each of the plurality of sliced portions by a cylindrical correction profile; and c) combining the iris diaphragm size data and the slit size data for each of the plurality of sliced portions with one Means for coalescing into a data array; d) means for generating a plurality of 1-bit resolution images from said data array; e) having a plurality of mirrors and corresponding said mirrors to said 1-bit resolution image A digital micromirror device configured to adjust to a plurality of patterns, Laser surgical system for deforming the cornea into a new shape. 44. f) further comprising a laser configured to direct a laser beam toward the digital micromirror device, the laser beam generated by the laser being formed into the shape of the pattern 44. The laser surgery system of claim 43 adapted to be redirected and directed towards the eye by a microscopic mirror device. 45. The laser surgery system of claim 43, wherein each of the 1-bit resolution images corresponds to a particular etch depth in the cornea.