KR20120065317A - Optical system for ophthalmic surgical laser - Google Patents

Abstract

Laser systems for ophthalmic surgery include laser sources for generating pulsed laser beams, XY scanners for scanning pulsed laser beams in the XY direction transverse to the Z axis, Z scanners for scanning XY scanned laser beams along the Z axis, and XYZ. And an objective that focuses the scanned laser beam onto a target area.

Description

OPTICAL SYSTEM FOR OPHTHALMIC SURGICAL LASER

This application claims the benefit and claims from this patent application "Optical Systems for Ophthalmic Surgical Lasers," Serial No. 12 / 511,958, filed Jul. 29, 2009, which application is hereby incorporated by reference in its entirety. Included.

The present invention relates to a system for the surgery of the anterior segment of the eye with a femtosecond laser, and more particularly to an embodiment that minimizes optical distortion of the laser beam while simultaneously scanning and focusing the laser beam into the eye.

The present application describes embodiments and embodiments of techniques and systems for laser surgery within the crystalline lens and the anterior segment of the eye via light disruption caused by laser pulses. Various lens surgical procedures for removal of the lens use various techniques to break the lens into small fragments that can be removed from the eye through small incisions. These procedures have significant defects, using manual instruments, ultrasound, heated fluids or lasers, including the need to enter the eye with a probe to achieve fragmentation and limited incisions associated with such lens fragmentation techniques. There is a tendency.

Photo-destructive laser technology can deliver laser pulses to the lens, thereby optically fragmenting the lens without the insertion of a probe, thus providing the potential for improved lens removal. Laser induced light destruction has been widely used in laser ophthalmic surgery, and Nd: YAG lasers have often been used as laser sources, including lens fragmentation through laser induced light destruction. Some existing systems include nanosecond lasers with pulse energies of several mJ (EH Ryan et al. American Journal of Ophthalmology 104: 382-386, October 1987; RR Kruger et al. Ophthalmology 108: 2122-2129, 2001). A picosecond laser with μJ (A. Gwon et al. J. Cataract Refract Surg. 21, 282-286, 1995) is used. These relatively long pulses create a relatively high level of unwanted exit risk, while at the same time placing a relatively large amount of energy into the surgical spot, resulting in a constrained limitation on the control and accuracy of the procedure. do.

At the same time, it has been recognized that in the related field of corneal surgery, shorter pulse durations and better focusing can be achieved by using pulses of hundreds of femtoseconds instead of nanosecond and picosecond pulses. Femtosecond pulses deploy much less energy per pulse, while significantly increasing the stability and accuracy of the procedure.

Several companies are currently commercializing femtosecond laser technology for ophthalmic procedures on the cornea, such as LASIK flaps and corneal transplants. These companies are based in Intralase Corp. / Advanced Medical Optics, 20/10 Perfect Vision Optische Gerate GmbH, Germany, Carl Zeiss Meditec, Germany, and Ziemer Ophthalmic Systems AG, Switzerland.

However, these systems are designed according to the requirements of corneal surgery. Crucially, the depth range of the laser focus is generally less than the thickness of the cornea, about 1 mm. As such, this design does not provide a solution to the contemplated attempt to perform surgery on the lens of the eye.

)에서도, 모두 밀리미터로, 방사방향 좌표(z, r)에서 개구수(NA) 및 스트렐비(S)를 갖고, (z, r) = (0.3, 0.0)의 부근에서, NA가 0.25과 0.40 사이에 존재하고 S가 0.8과 1.0 사이에 존재하며, 각 목표 영역들인 (z, r) = (0.3, 6.2)의 부근에서, NA가 0.25와 0.40 사이에 존재하고 S가 0.8과 1.0 사이에 존재하는 목표 영역, (z, r) = (8.0, 0.0)의 부근에서, NA가 0.15와 0.35 사이에 존재하고 S가 0.8과 1.0 사이에 존재하는 목표 영역, 및 (z, r) = (7.4, 4.0)의 부근에서, NA이 0.15와 0.35 사이에 존재하고 S가 0.8과 1.0 사이에 존재하는 목표 영역 중 적어도 하나 내에 NA 및 S가 존재한다. Briefly and generally, a laser system for ophthalmic surgery includes a laser source that generates a pulsed laser beam, an XY scanner that scans the pulsed laser beam in the XY direction transverse to the Z axis, and an XY scanned laser beam along the Z axis. A Z scanner, and an objective that focuses the XYZ scanned laser beam to the target area, wherein the focused scanned laser beam is in a range of azimuth angles within the target area.

) Also has a numerical aperture (NA) and a strel ratio (S) in the radial coordinates (z, r), and in the vicinity of (z, r) = (0.3, 0.0), NA is 0.25 and 0.40. S is between 0.8 and 1.0, and in the vicinity of each target region (z, r) = (0.3, 6.2), NA is between 0.25 and 0.40 and S is between 0.8 and 1.0 In the vicinity of (z, r) = (8.0, 0.0), NA is between 0.15 and 0.35 and S is between 0.8 and 1.0, and (z, r) = (7.4, In the vicinity of 4.0), NA and S are present in at least one of the target regions where NA is between 0.15 and 0.35 and S is between 0.8 and 1.0.

In an implementation NA and S are in two of three respective target regions. In the implementation NA and S are in all three respective target regions.

In the implementation, the vicinity of the radial coordinates (z, r) includes points, wherein the radial coordinates of the points do not deviate from the radial coordinates (z, r) to exceed P ( radial ) percentages, and P ( radial ) is 10 One of%, 20% and 30%.

In the practice, in the vicinity of (z, r) = (0.3, 0.0), NA is between 0.30 and 0.35 and S is between 0.8 and 1.0, and each of the following target regions (z, r) = (0.3 , In the vicinity of 6.2), NA is between 0.30 and 0.35 and S is between 0.8 and 1.0, and in the vicinity of (z, r) = (8.0, 0.0), NA is between 0.20 and 0.25 A target region that exists and S is between 0.8 and 1.0, and a target region where NA is between 0.20 and 0.25 and S is between 0.8 and 1.0, in the vicinity of (z, r) = (7.4, 4.0) NA and S are present in at least one of.

In an implementation NA and S are in two of three respective target regions. The laser system according to one embodiment, wherein NA and S are present in all three respective target areas.

In the implementation, the vicinity of the radial coordinates (z, r) includes points, wherein the radial coordinates of the points do not deviate from the radial coordinates (z, r) to exceed P ( radial ) percentages, and P ( radial ) is 10 One of%, 20% and 30%.

In practice the NA and S values relate to a laser system optically coupled to one of the human eye and one of the models of the eye via the patient interface.

In an embodiment the eye model comprises a first surface, a second surface and a third surface, wherein the corneal region is defined to have a thickness of about 0.6 mm and a refractive index of about 1.38, with the antechamber region being 2 mm. to is defined as having a refractive index of about 1.34 and a thickness in the range of 4㎜, is defined as having a refractive index of about 1.42 and a thickness in the range of the lens area to 3㎜ 5㎜, all three surfaces ^- 100m - ^It has a curvature in the range of ¹ to -80 m ^-1 .

In practice the laser system further comprises a precompensator located between the laser source and the XY scanner.

In practice the precompenator has a movable lens and Z scans the laser beam.

In an implementation the Z scanner is configured to substantially adjust the Z focal depth and the numerical aperture NA independently.

In an embodiment the Z scanner comprises a first lens group and a movable beam scanner.

In an implementation the Z scanner is positioned separately from the objective in front of the objective.

In practice, the laser system for ophthalmic surgery includes a laser source for generating a pulsed laser beam, an XY scanner for scanning the pulsed laser beam in the XY direction transverse to the Z axis, a Z scanner for scanning the XY scanned laser beam along the Z axis, And an objective for focusing the XYZ scanned laser beam into the target area, wherein the focused scanned laser beam has a focus with a focal radius, the focal radius being less than r _f ( max ) within the target area, Extends about 8 millimeters along the Z axis and about 10 millimeters in the XY direction.

In the practice r _f ( max ) is 2 micrometers or 4 micrometers and is associated with a laser system coupled to one of the human eye and a model of the human eye.

1 shows a surgical laser delivery system 1.
2 shows an off wavefront W and a Gaussian wavefront G. FIG.
3A and 3B show light rays at the optimal scanned focal plane.
3C shows the definition of the focal radius.
4 shows the relationship between the RMS wavefront error (ω) and the strel ratio (S).
5 shows a reference point for ophthalmic surgery.
6A and 6B conceptually illustrate the operation of the precompilator 200.
7A and 7B illustrate various uses of an efficient Z scanning function.
8A-8D illustrate the implementation of the precompilator 200.
9 shows an implementation of a laser delivery system 1 with two Z scanners.
10 shows a table of configurations including zero, one or two Z depth scanners and zero, one or two NA adjusters.
11A-11C show an XY scanner with two, three and four scanning mirrors.
12A-12D show the corresponding optical numerical aperture NA _opt (z) as a function of aberration and Z focal depth as a function of numerical aperture.
13A and 13B show two settings of the first beam expander block 400 and the movable beam expander block 500.
14 shows the middle focal plane of the Z scanner 450.
15 illustrates an implementation of objective 700.
16 shows a focal plane bent at the target area.
17 shows the nomogram of the XY scanner tilt angle.
18 shows a nomogram of movable beam expander positions.
19 illustrates the steps of a computerized control method.

Some embodiments of the present invention include a system for surgery in the lens of the eye using femtosecond laser pulses. In addition, some integrated embodiments may perform both corneal and lens surgical procedures. Performing ophthalmic surgery on the lens of the eye involves qualitatively different requirements than corneal procedures.

Key differences between the presently described lens surgical laser system and corneal system include:

1. A femtosecond laser pulse is generated reliably. High repetition rate femtosecond pulses allow much less control per pulse, while providing much higher control and accuracy for the operator of the system. However, reliably generating femtosecond pulses is a significantly larger attempt than nanosecond or picosecond pulses, used by some existing systems.

2. The surgical laser beam is markedly refracted when propagating through refractive media up to 5 millimeters, reaching the surgical target, the lens, including the cornea and the anterior aqueous chamber. On the other hand, the laser beam used for corneal surgery is focused on the depth of a portion of the millimeter and is therefore substantially refracted as it enters the cornea from the surgical system.

3. Surgical The laser delivery system is configured to scan the entire surgical area, for example from anterior / front at a typical depth of 5 mm to posterior / rear at a typical depth of 10 mm. This 5 mm or greater depth-scanning range, or “Z scanning range,” is significantly wider than the 1 mm depth-scanning used for surgery on the cornea. In general, surgical optics, substantially the high numerical aperture optics used herein, are optimized for focusing the laser beam at a particular operating depth. During the corneal procedure, 1 mm depth-scanning causes only a moderate deviation from the optimized operating depth. On the other hand, during a scan of 5-10 mm during lens surgery, the system is driven away from the fixed optimized working depth. Thus, the lens surgical laser delivery system employs much improved adaptive control optics to scan the wide depth-scanning range required by lens surgery.

4. Some embodiments are integrated in the sense that they are configured to perform surgery on both cornea and lens. In such integrated embodiments the depth-scanning range may be up to 10 mm instead of 5 mm, taking much more difficult attempts.

5. During corneal surgery procedures, such as many variants of LASIK, the laser beam is scanned perpendicular to the optical axis ("in the XY plane"). In the general procedure, the XY scanning range covers the center of the cornea with a diameter of only 10 mm. However, additional cuts may also be formed in an integrated surgical system. One form of cut is an entry cut, which provides access to the interior of the eye for conventional surgical instruments and aspiration needles. Another form of cut is limbal relaxing incision (LRI), which involves making a pair of incisions in the immediate anterior corneal limbus to the vascular arcade. By adjusting the length, depth and position of this arcuate incision, one can induce a change in corneal astigmatism. Entry cuts and LRIs can be located around the cornea, generally having a diameter of 12 mm. Increasing the XY scanning diameter of 10 mm to 12 mm diameter is a 20% increase compared to the constant diameter of the LASIK flap, whereas off-axis aberration results in the field diameter at the focal plane. As it grows in proportion to higher forces, it is an important attempt to retain the off-axis aberration of the laser delivery system under control at this diameter.

6. Lens laser surgical procedures may require guidance from complex imaging systems. In some imaging devices, limbal blood vessels are identified and serve as a reference to the eye, and in some cases relative to the reference coordinates identified during preoperative diagnosis of the eye, the cyclo-rotational alignment of the eye during surgery rotational alignment). The blood vessels selected around the surgical area may not be shaken most by the surgery and thus most certain. However, an imaging system oriented to such peripheral blood vessels requires imaging optics to photograph an area larger than 10 mm, for example with a 12 mm radius.

7. The laser beam grows various aberrations during transmission along the optical path within the eye. Laser delivery systems can improve accuracy by compensating for these aberrations. An additional aspect of this aberration is that it depends on the frequency of light, in fact referred to as "chromatic aberration". Compensating aberrations along these frequencies increases the attempt on the system. The difficulty of compensating for this chromatic aberration increases with the bandwidth of the laser beam of the laser system. It is recalled that the spectral bandwidth of the beam is inversely proportional to the pulse length. Thus, the bandwidth for femtosecond pulses is often greater than the bandwidth of picosecond pulses by an order of magnitude or more, often requiring much better color compensation in femtosecond laser systems.

8. Surgical procedures using a high repetition rate femtosecond laser surgical system require high accuracy in positioning each pulse relative to the absolute position and relative to the target position in the target tissue. For example, a laser system may be required to redirect beams only a few microns within the time between pulses, which may be about microseconds. Because of the short time between two consecutive pulses and the high accuracy requirements for pulse position, manual targeting as used in existing low repetition rate lens surgical systems is no longer appropriate or feasible.

9. The laser delivery system is configured to deliver femtosecond laser pulses through the refractive medium to the overall surgical volume of the lens of the eye, with maintained time, spectral and spatial integrity.

10. In order to ensure that the tissue only receives a laser beam with a high energy density sufficient to cause a surgical effect, for example tissue ablation, in the surgical area, the laser delivery system uses a very high numerical aperture ( numerical aperture (NA). This high NA results in a small spot size and provides the necessary control and accuracy for the surgical procedure. Typical ranges for the numerical aperture may include NA values greater than 0.3, resulting in spot sizes of less than 3 microns.

11. Given the complexity of the optical path of the laser for lens surgery, the laser delivery system achieves high accuracy and control by including a high performance computer-managed imaging system, whereas the corneal surgery system has no or low Satisfactory control can be achieved with a level of imaging. In particular, the surgical and imaging functions of the system, as well as the conventional observation beam in general, all operate in different spectral bands. As an example, the surgical laser may operate at a wavelength in the band of 1.0 to 1.1 microns, the observation beam may operate in the visible band of 0.4 to 0.7 microns, and the imaging beam may operate in the band of 0.8 to 0.9 microns. Can be. Combining beam paths in optical components, common or shared, places demanding color requirements on the optics of a laser surgical system.

Differences 1 to 11 indicate that (ii) ophthalmic laser surgery on (i) lenses with femtosecond pulses may induce requirements that are qualitatively different from those of corneal surgery and even lens surgery using only nanosecond or picosecond laser pulses. Shown through some embodiments.

1 shows a laser delivery system 1. Before describing in detail, we mention that some embodiments combine the laser delivery system of FIG. 1 with an imaging or observation system. In some corneal procedures, such as in the LASIK process, an eye tracker generally sets the positional criteria of the eye by visual cues, such as identification of the center of the iris by imaging and image processing algorithms, on the surface of the eye. Establish. However, since surgical procedures are performed in the outermost layer of the eye, the cornea, existing target trackers recognize and analyze characteristics in two-dimensional space without depth information. Often, the cornea is flattened evenly, making the surface exactly two-dimensional.

The situation is quite different when focusing the laser beam from the lens, deep inside the eye. The lens may vary in position, shape, thickness and diameter during surgery, as well as between previous measurements and surgery. Attaching the eye to the surgical equipment by mechanical means can also change the shape of the eye in an unclear manner. Such attachment device may include fixing the eye with a suction ring or aplanating the eye with a flat or bent lens. Moreover, movement of the patient during surgery can introduce additional changes. This change can add up to a few millimeters of displacement of visual cues within the eye. Thus, when performing precision laser surgery on the lens or other medial portion of the eye, it is not satisfactory to mechanically reference and fix the surface of the eye, such as the limbus or the anterior surface of the cornea.

To address this problem, the laser delivery device 1 is R.M. As described in co-pending US patent application Ser. No. 12 / 205,844 by Kurtz, F. Raksi and M. Karavitis, it may be combined with an imaging system, which is hereby incorporated by reference in its entirety. The imaging system is configured to photograph a portion of the surgical area to establish three-dimensional location criteria based on the medial characteristics of the eye. Such images can be generated before surgery and updated in parallel with the surgical procedure to account for individual changes and changes. The image can be used to safely orient the laser beam at the desired location with high accuracy and control.

In some implementations, the imaging system can be an optical coherence tomography (OCT) system. The imaging beam of the imaging system may have an optical path that is partially or fully shared with or separate from the surgical beam. Imaging systems with partially or fully shared optical paths reduce costs and simplify the calibration of imaging and surgical systems. The imaging system may also use the same or different light source as the laser of the laser delivery system 1. The imaging system may also have its own beam scanning subsystem, or may make use of the scanning subsystem of the laser delivery system 1. Several different structures of such OCT systems are described in the referenced co-pending application.

The laser delivery system 1 can also be implemented in combination with visible observation optics. Observation optics help the operator of the surgical laser observe the effect of the surgical laser beam and control the beam for observation.

As a result, in some implementations, using infrared and thus invisible surgical laser beams, additional tracking lasers operating at visible frequencies may be employed. A visible tracking laser can be implemented to track the path of the infrared surgical laser. The tracking laser can be operated at an energy low enough to not cause any disruption of the target tissue. The viewing optics may be configured to orient the tracking laser, reflected from the target tissue, to the operator of the laser delivery system 1.

In FIG. 1, the beam associated with the visible observation optics and imaging system may be coupled to the laser delivery system 1, for example, via a beam splitter / dichroic mirror 600. This application will not extensively refer to various combinations of laser delivery systems with imaging, observation and tracking systems. A large number of such combinations, all of which are mentioned broadly in the incorporated US patent application 12 / 205,844, are all within the full scope of the present application.

1 includes a laser delivery system 1, which includes a laser engine 100, a precompensator 200, an XY scanner 300, a first beam expander block 400, and a movement. Possible beam expander block 500, beam splitter / chromatic mirror 600, objective 700 and patient interface 800, including first beam expander block 400 and movable beam expander Block 500 will be referred to as Z scanner 450 in connection.

In many implementations below, prior art is used in which the Z direction is substantially along the optical axis of the optical element or the optical path of the laser beam. The direction transverse to the Z direction is called the XY direction. In a broad sense the term transversal direction is used in some embodiments to include that the transversal direction and the Z direction cannot be strictly perpendicular to each other. In some implementations the transverse direction may be better described with respect to radial coordinates. Thus, the term splitting direction, XY direction or radial direction all refer to a similar direction in the described implementation, which is approximately perpendicular to (but inevitably accurately) the Z direction.

1. Laser Engine (100)

The laser engine 100 may emit a laser pulse having a predetermined laser parameter, including a laser. Such laser parameters may include a pulse duration in the range of 1 femtosecond to 100 picoseconds, or in the range of 10 femtoseconds to 10 picoseconds or in some embodiments in the range of 100 femtoseconds to 1 picoseconds. The laser pulses may have energy per pulse in the range of 0.1 micro joules to 1000 micro joules, and in other embodiments in the range of 1 micro joule to 100 micro joules. The pulse may have a repetition frequency in the range of 10 Hz to 100 MHz, in other embodiments in the range of 100 Hz to 1 MHz. Other embodiments may have a combination of such range limitations, for example, laser parameters present within a range of pulse periods of 1 to 1000 femtoseconds. Laser parameters for a particular procedure may be selected within this wide range, for example, during a preoperative procedure, or may be based on calculations based on specific data of the patient, for example his / her age.

Embodiments of the laser engine 100 may include Nd: glass and Nd: Yag lasers, and various other lasers. The operating wavelength of the laser engine may be in the infrared or visible range. In such embodiments the operating wavelength may be in the range of 700 nm to 2 microns. In some cases the operating wavelength may be in the range of 1.0 to 1.1 microns, for example in an infrared laser based on Yb or Nd.

In some implementations the laser parameters of the laser pulses may be adjustable and changeable. The laser parameters can be adjustable with a short switch time so that the operator of the surgical laser delivery system 1 can change the laser parameters during complex surgery. This change in parameter can be initiated for reading by the sensing or imaging subsystem of the laser delivery system 1.

Other parameter changes may be performed as part of a multi-step procedure while the laser delivery system may first be used in a first surgical procedure, followed by a second, different surgical procedure. Embodiments include first performing one or more surgical steps in the area of the lens of the eye, such as a capsulotomy step, followed by a second surgical procedure in the corneal area of the eye. This procedure can be performed in various orders.

Lasers of high repetition rate pulses operating at pulse repetition rates of tens of thousands to hundreds of thousands of shots per second with relatively low energy per pulse can be used in surgical applications to achieve certain advantages. Such lasers use relatively low energy per pulse to localize the tissue effects caused by laser induced photodestruction. In some implementations, for example, the limit of disrupted tissue may be limited to several microns or tens of microns. Such localized tissue effects can improve the accuracy of laser surgery and may be desirable in certain surgical procedures. In various implementations of this surgery, hundreds, thousands, or millions of pulses can be delivered in an order of contiguous, nearly contiguous, or separated spots by a controlled distance. Such practice can achieve certain desired surgical effects, such as tissue dissection, separation or fragmentation.

The parameters of the scan pattern and pulse can be selected by various methods. For example, they may be based on preoperative measures of the optical or structural properties of the lens. Laser energy and spot separation can also be selected based on age-based algorithms or preoperative measures of the optical or structural properties of the lens.

2. Precompensator (200)

, 여기서, n_i는 이미지 공간에서 매체의 굴절률이고,

은 점들(Q1, Q2)의 거리이다. 2 shows that the wavefront of the laser beam can deviate from the ideal behavior in several different ways for several different causes. This deviation of large groups is called aberration. Aberrations (and other wavefront distortions) replace the actual image points from the ideal axial Gaussian image points. 2 shows a wavefront of light exiting through the exit pupil ExP. The distorted spherical wavefront G emerges from the pupil and converges to the point P1 at the center of curvature of the wavefront G. G is also called a Gaussian reference sphere. The off wavefront W deviates from G and converges to a different point P2. The aberration ΔW of wavefront W off point Q1 can be characterized by the optical length of the path to the distorted reference sphere G:

, Where n _i is the index of refraction of the medium in image space,

Is the distance of points Q1 and Q2.

In general, the aberration ΔW depends on coordinates both in the focal plane as well as in the exit pupil. Thus, this aberration ΔW can also be considered as a correlation function: the set of points where r 'is removed from P1 on the optical axis and the image converges to P2 is located on the surface W, which is emitted It is shown that the distance from the pupil ExP deviates from the reference sphere G by the amount of ΔW in the radial distance r. For rotationally symmetrical systems,

에 따라 ΔW는 r 및 r'에서 이중 멱급수 확장에 대하여 기록될 수 있다.

ΔW can be recorded for double power expansion at r and r '.

Where r 'is the radial coordinate of image point P2 at the focal plane and r is the radial coordinate of point Q1 at the pupil. The angle dependence is represented by the spherical angle, Θ. n = 2p + m is a positive integer and _{2l + m} a _nm is the coefficient of expansion of the off-wave surface (W). For reference, see, for example, Optical Imaging and Aberrations, Part I. by Virendra N. Mahajan of SPIE Optical Engineering Press. See Geometrical Optics. The order i in aberration terms is given by i = 2l + m + n.

Terms up to i = 4 relate to major aberrations: spherical, coma, astigmatism, visual curvature and distortion. The actual relationship between _{2l + m} a _nm aberration coefficients and these major aberrations is reported in the literature. For systems of shooting point objects, the explicit dependence of the aberration on the image radius r 'can be suppressed by introducing a dimensionless variable ρ = r / a, where a is the transverse linear limit of the exit pupil, eg For example, its radius is:

here,

The benefit of this notation is that all of the aberration coefficients (a _nm ) have dimensions of length and represent the maximum of the corresponding aberration in the exit pupil. In this notation, for example, spherical aberration is characterized by the aberration coefficient a ₄₀ .

While the description of the aberration for the aberration coefficient (a _nm ) is well defined mathematically, this is not always the experimentally most accessible approach. Thus, three alternative measures of aberration are described below.

In experimental accessibility and testability of the same vein, it is indicated that the behavior of the beam in biological tissues, such as the eye, may not be the easiest to measure. To help, studies show that light in the eye can behave quite similarly to light in saline with physically adequate salt concentrations, and can be measured and accounted for qualitatively. Thus, when application is described in the behavior of the laser delivery system in the eye, it is understood that this description refers to the behavior in either the described eye tissue or the corresponding saline.

3A-3C show a second measure of aberration. The laser delivery system 1, which was configured to focus the beam at the focal plane 210 at depth A, is instead spherical if operated to focus the beam at the working focal plane 211 at depth B. It can cause aberrations. When the focus of the laser beam is moved from the focal plane 210 to the focal plane 211, this situation can occur, for example, during a three-dimensional scanning procedure.

3A shows the case when the laser delivery system 1 focuses the light beam on the optimum focal plane 210. The light ray passes through the spot (“focus”) at the optimal focal plane 210 of quite narrow radial limits, or radius r _f (A). This radial limit r _f (A) can be greater than zero for various reasons, for example the diffraction of the light beam. The radius of focus can be defined in one or more ways. The general definition of r _f (A) is the minimum radius of the light spot on the screen as the position of the screen changes along the axis or Z direction. This Z depth is often referred to as the "point of least confusion". This definition is further refined with respect to FIG. 3C.

3B shows the case when the laser delivery system 1 scans the focal point out of the optimum focal plane 210 by a slight distance, for example several millimeters, into the working focal plane 211. Visually, the light beam passes through a focal point of radius r _f (B) greater than r _f (A), causing spherical aberration. Equations of varying accuracy have been grown connecting the aberration coefficient (a _nm ) and the focal radius (r _f ). In some cases, the focal radius r _f is an experimentally more accessible measure for quantifying aberrations than a _mn aberration coefficients.

3C shows a better quantitative definition of the focal radius r _f . 3c shows the energy contained in the spot of radius r, measured from the center of the beam. A widely accepted definition of the focal radius r _f is the radius in which 50% of the energy of the beam is contained therein. The curve labeled “A” shows that in a diffraction limited beam, as in FIG. 3A, when the beam is focused on the optimal focal plane 210, 50% of the energy of the beam provides a useful definition of r _f (A). , At a spot of radius r = 0.8 micron, can be included or enclosed.

If the energy of the laser beam is placed at a properly or clearly defined focal point, surgical procedures based on laser induced optical breakdown (LIOB) will have higher accuracy and efficiency, and smaller unwanted effects. Can be. LIOB is a significant nonlinear process with an intensity (plasma-) threshold: in general, tissues exposed to beams having a higher intensity than plasma thresholds become plasma, while intensity below the plasma threshold Tissues exposed to the beams with do not undergo plasma transition. Thus, widening the focus by aberration reduces the portion of the beam that achieves higher intensity at the focal point than the plasma threshold, and increases the portion of the beam whose intensity remains below the threshold. Some of these latter beams are not efficiently absorbed by the target tissue and propagate through the eye tissue to the retina in most cases, causing potentially unwanted corneal exposure.

For surgical procedures aimed at correcting the cornea, the focal plane is generally about 0.6 from the optimal or nominal depth, since the cornea is substantially 0.6 mm thick and, in rare cases, thicker but still no more than 1 mm. Only mm is scanned or moved in the Z direction (along the optical axis). The curve labeled “B” indicates that 50% of the beam's energy is r when the focal plane of the beam is moved from the optimal focal plane 210 to the working focal plane 211 by about 1 mm (the upper limit estimate for the corneal procedure). _f (B) = 1.8 microns, to be included within the focal radius. While this movement introduces aberrations, the scale is limited. Thus, some existing corneal laser systems do not compensate for this aberration at all, while others introduce only a slightly limited level of compensation.

In addition to the aberration coefficient a _mn and the focal radius r _f , the third measure of aberration is the so-called Strehl ratio (S). The strel ratio (S) of a system is defined as the peak intensity of the beam at the focal plane of the system divided by the theoretical maximum peak intensity of the same and perfect imaging system, with reference to the beam exiting from the point source, which is diffraction limited. Works on Equivalent definitions are also known in the literature and are within the scope of the definition of Strelby (S).

Corresponding to this definition, the smaller the value of S, the larger the aberration. The non-deviating beam has S = 1, and conventionally, when S> 0.8, the imaging system is known to be diffraction limited.

The fourth definition of aberration is ω, the mean square root (root) representing the deviation (W) of the wavefront (W) deviating from the undistorted wavefront (G) of FIG. 2 averaged over the entire wavefront at the exit pupil (ExP). -mean-square) or RMS, wavefront error. ω is expressed in units of wavelength of the beam, creating a dimensionless amount.

4 shows that for relatively small aberrations ω and S are related by the following empirical formula:

Regardless of the type of aberration,

Where e is the base of the natural logarithm.

All four of the above measures of aberration are useful for diagnosing problems and optimizing the design of the laser delivery system 1. Thus, the general term “aberration measure” below may refer to either one of these measures or their equivalents. In particular, increasing the aberration is obtained by increasing the aberration coefficient a _mn , the focal radius r _f and the RMS wavefront error ω, but by decreasing the strel ratio S.

The relationship between these aberration measures is illustrated by showing the spherical aberration coefficient a ₄₀ and the corresponding strel ratio S in a particular embodiment. In an embodiment, the surgical laser system focuses the laser beam on eye tissue at different depths below the surface. The laser beam is diffraction limited, with a wavelength of 1 micrometer and NA = 0.3 numerical aperture, and is focused on the surface of the tissue at a standard angle of incidence. The number of such embodiments can be similar to the effect of adding a planar parallel plate of the same thickness as the depth scanned near the focal plane of the system, and performing the calculations for the brine.

The surface of the tissue introduces aberrations into the beam, characterized by equations (2) and (3). The spherical aberration, characterized by the aberration coefficient a ₄₀ , is zero at the surface, and the strel ratio due to the significant structure is S = 1.

Lasik surgery generally forms a flap to a depth of 0.1 mm. At this depth, the strel ratio S is reduced to about 0.996, only a small decrease. Even at a depth of 0.6 mm, approximately at the posterior surface of the cornea, S is about 0.85. This is a negligible reduction in peak intensity, while still compensating by adjusting the laser beam intensity.

On the other hand, at a depth of 5 mm, which characterizes the anterior surface of the lens in the eye, the strel ratio can be reduced to S = 0.054. At this depth and strel ratio, the beam intensity is significantly reduced below the plasma threshold, so the beam cannot generate LIOB. This sudden loss of peak intensity cannot be compensated for by increasing the laser power without unwanted effects, such as overexposure or excessively increased bubble size of the retina.

Table 1 shows the spherical aberration (a ₄₀ ), corresponding to the just described Strelby. Visually, spherical aberration increases approximately linearly with tissue-depth, while strelby ratio S behaves in a non-linear fashion:

[Table 1]

In surgical procedures aimed at performing lens lysis, capsulotomy or other surgical procedure on the lens, the focal plane is often scanned over the entire depth of the lens, which can be as much as 5 mm. Moreover, in an integrated corneal-lens system, the total scanning depth can extend about 10 mm from the cornea to the posterior surface of the lens. The curve labeled “C” in FIG. 3C shows that in this case the focal radius grows to r _f (C) = 18 microns, and this value is too large to appear evenly on the same configuration as r _f (A) and r _f (B). It does not. In some embodiments, the optimal focal plane can be selected and placed halfway in the depth-scanning range, and the laser beam can be scanned in a plus / minus 5mm depth range. In this case r _f (C) can be reduced to 10 microns.

This large r _f (C) value is converted into a large positive aberration on the other three aberration measures (a ₄₀ , S, ω). Clearly, for corneal procedures that scan only tens of millimeters, this large aberration of lens surgery takes many attempts to design the laser delivery system 1 to compensate or manage unwanted outcomes.

In order to address the problem of large aberration measures associated with lens surgery, some embodiments include precompensator 200 to precompensate and improve aberration measures. This aberration may be grown in the target tissue, or along a portion of the optical path within the laser delivery system 1, or along the entire optical path.

)에서도 위치될 수 있다. 따라서, 이런 P 점들은 단지 3개의 실린더 좌표들 중 2개에 의해 언급될 것이고, 방위각(

)은 억제된다. P1은 중심에 위치된 각막 절차를 위한 일반적인 점이고, P2는 주변 각막 절차를 위하여 일반적이며, P3은 렌즈의 전방 영역에 관련되고, P4는 렌즈의 후방에 관련되며, P5는 주변 렌즈 기준점이다. 다른 기준점들은 또한 채택될 수 있어 레이저 전달 시스템의 수차를 특징짓는다. 몇몇 경우들에서, 수차 척도는 작동 파면 또는 조사된 영역에 걸쳐 평균을 낸 수차 척도를 언급할 수 있다.Fig. 5 is followed when the aberration scale is estimated to estimate a value, where the aberration scales r _f (C), a ₄₀ , S, ω are radial distances r from the optical axis and depth of focus z. It is shown (without a scale) that this will refer to aberration measures that estimate the value described at some selected reference points. The set of related reference points can be described by cylinder coordinates (z, r): all in millimeters, P1 = (0,0), P2 = (2,6), P3 = (5,0), P4 = ( 8,0), P5 = (8,3). Since the main structure of the eye exhibits approximately cylinder symmetry, these P reference points

Can also be located. Thus, these P points will be referred to by only two of the three cylinder coordinates,

) Is suppressed. P1 is a general point for centrally located corneal procedures, P2 is common for peripheral corneal procedures, P3 is relative to the front region of the lens, P4 is relative to the rear of the lens, and P5 is the peripheral lens reference point. Other reference points can also be employed to characterize the aberration of the laser delivery system. In some cases, the aberration scale may refer to the aberration scale averaged over the operating wavefront or irradiated area.

Aberration measures can be determined in several different ways. The wavefront of the laser beam can be tracked in a computer-aided design (CAD) through a selected portion of the optical path, for example a model of the target tissue or a portion of the laser delivery system 1. In addition, the aberration of the laser beam can be measured with an actual laser delivery system or a combination of these two procedures.

Thus, in some implementations, the presentation introduced by the precompilator 200 may be selected by determining, calculating or measuring aberration measures along a selected portion of the optical path, which includes the target tissue itself. And then determine the amount of presentation needed to compensate for the preselected portion of the determined / calculated / measured aberration.

Since the spherical aberration predominantly affects the axial rays, the precompilator 200 can efficiently correct or present the spherical aberration. Other forms of aberration, such as transverse aberration, astigmatism and coma, affect non-zero angular rays as well as field rays, including rays offset from the optical axis. Whereas the laser beam generated by the laser engine 100 is a substantially axial beam, the various blocks in the optical path, the most obvious XY scanner 300, transform the axial beam into a non-zero angle beam with field rays. Let's do it.

Thus, in designs where the precompilator is located behind the XY scanner 300, the field rays of the beam may grow some different aberrations. (Iii) The optimization of the beam may require compensating some aberrations, and (ii) the generation of these different aberrations takes considerable design effort because the different forms of aberrations are not independent of each other. Thus, compensating one form of aberration generally leads to another form of unwanted aberration.

Thus, in the structure where the compensator is located behind the XY scanner, spherical aberration is generally compensated to a limited degree in exchange for introducing other types of unwanted aberrations.

On the other hand, embodiments of the present laser delivery system 1 may have a precompilator 200 in front of the XY scanner 300. This design allows the precompilator 200 to compensate for spherical aberrations without introducing other forms of unwanted aberrations.

Some implementations even utilize the interdependence of on-axis and off-axis aberrations mentioned above by introducing on-axis presentation by the precompilator 200, so that a continuous segment of target tissue or laser delivery system can be utilized. The off-axis aberration caused by is presented.

6A and 6B schematically illustrate the idealized operation of the precompilator 200.

6a shows a laser delivery system 1 without precompilator. In general, the optical path segment 301 may introduce some level of spherical aberration. This is illustrated by the wavefront with the aberration leaving the optical path segment 301 and the undistorted wavefront entering the optical path segment 301. Such a segment may be any segment of the optical path, for example part of the target tissue or part of the path in the entire target tissue or laser delivery system 1.

6B shows that precompilator 200 may introduce compensating (or complementary) distortion of the wavefront. This presented wavefront then enters the optical path segment 301, which causes the wavefront to have a reduced distortion or even no distortion.

Some existing systems do not have a dedicated compensator at all. Other systems may also compensate for spherical aberration only in a manner distributed by the lenses of the lens groups located behind the XY scanner with other functions. In this existing system, the parameters of the lenses are selected as a result of making a compromise between different functions, leading to performance limitations.

On the other hand, embodiments of the laser delivery system 1 may have a dedicated precompilator 200 located in front of the XY scanner 300. In some embodiments, precompilator 200 is a first optical unit, or lens group, which receives a laser beam from laser engine 100. Because of the location the laser beam reaches the precompilator 200 without growing field rays or non-zero angular rays (which may be caused by the XY scanner 300), these embodiments exhibit high levels of appearance. Can be achieved. The presentation is also the main function of the precompilator 200 and is therefore efficient because the design compromise can be kept quite limited, in contrast to existing systems, which compensates with lenses providing additional functionality. .

For these causes, it is possible in this implementation to correct spherical aberration to a high degree without affecting or introducing other forms of aberration.

In the theory of aberrations, it is known that the spherical aberration of a compound lens system is approximately the sum of the spherical aberrations of the individual components. Thus, in some implementations of the laser delivery system 1, an unwanted amount of spherical aberration can be introduced by designing the precompilator 200, introducing the same amount of aberration with the opposite sign.

As an example, when the depth of focus in the eye tissue is shifted 5 mm out of the optimal focal plane, the spherical aberration a ₄₀ (according to Table 1) is -2.0 micrometers. Thus, in some implementations precompilator 200 may introduce aberration measures of a ₄₀ = +2.0 micrometers. In a first approximation, this manifestation substantially eliminates spherical aberration caused by 5 mm shift of focus, thus increasing the strel ratio from S = 0.054 to S = 1 again. (This simple example ignores other sources of aberration.)

Some implementations below describe the aberration measures of the "non-precompensated" laser delivery system 1, i.e., the laser delivery system from which the precompensator 200 has been removed, the "precompensated" laser. It will be characterized by comparison with a delivery system, ie a system where the precompilator 200 is not removed.

In some implementations, pre-Com pense S (precomp <S for S (precomp) The laser delivery system (1) compensation line from> data value of the laser delivery system (1) Preparing a 200 uncompensated line S Increase the strel ratio. In some embodiments, for example, S ( precomp ) may be 0.6, 0.7, 0.8 or 0.9.

As explained above, this strel ratio (S) is any one or several of the strel ratios (S (P1), ... S (P5)) at the five reference points P1 to P5 above. The other predetermined reference points may refer to the strel ratio, or the average of the strel ratios over five reference points or the average over the operating wavefront.

Strelby may also refer to the entire laser delivery system 1, which receives the laser beam from the laser engine 100, ends with the objective 700, and focuses the ophthalmic target tissue. In some other cases, the term may refer to other targets that include air. In some implementations the term may refer to a subsystem of the laser delivery system 1.

In some implementations, the addition of the precompilator 220 to the unshown laser delivery system 1 results in an S for a pulse having an associated bandwidth that is at least 10 times greater than the strain limited bandwidth of the laser pulse over a period of picoseconds or more. = S (precomp) can increase the host relbi in a line above the compensation value S (precomp) from the value uncompensated line below. As above, for example, S ( precomp ) may be 0.6, 0.7, 0.8 or 0.9.

Additional free Com pense data 200 for the laser delivery system (1) in some embodiments are S = S (precomp from the uncompensated value: S = S (precomp) over a range of from 0.4 micron to 1.1 micron wavelength ) Can be increased to the values shown above. As above, for example, S ( precomp ) may be 0.6, 0.7, 0.8 or 0.9.

In some implementations the addition of the precompilator 200 may result in a precompilator from values not exhibited below NA = NA ( precomp ), corresponding to the laser delivery system 1 without the precompilator 200. It is possible to increase the system numerical aperture to a value presented above NA = NA ( precomp ) with (200). For example, the value of NA (precomp) in some embodiments can be 0.2, 0.25, 0.3 or 0.35.

In some implementations the addition of the precompilator 200 to the laser delivery system 1 without the precompilator r _f (corresponding to the laser delivery system 1 with the precompilator 200). precomp ) can reduce the focal radius r _f in the target tissue from the non- presented value above r _f ( precomp ) to the presented value below. In some implementations, r _f ( precomp ) can be 2, 3 or 4 microns.

In some implementations, pre-Com value of pense data laser delivery system (1) Preparing a 200 uncompensated line ω> ω (precomp) ω <ω (precomp for the from line compensated laser delivery system (1) ) Can increase the RMS wavefront error. In some embodiments, for example, ω ( precomp ) may be 0.06, 0.07, 0.08 or 0.09, all in units of wavelength of the laser beam.

In some implementations, the installation of the precompilator 200 may result in a ₄₀ <for the laser delivery system 1 presented from the values a ₄₀ > a ₄₀ ( precomp ) of the undelivered laser delivery system 1. You can increase the spherical aberration coefficient with a ₄₀ ( precomp ). In some embodiments, for example, a ₄₀ ( precomp ) may be 2, 3 or 4 micrometers.

In some implementations, installing the precompilator 200 into the unshown laser delivery system 1 results in the following aberration measures from a value that is not compensated at least by the show percentage P ( precomp ): RMS It is possible to reduce at least one of the wavefront error ω, the spherical aberration measure a ₄₀ and the focal radius r _f , or increase the strel ratio S by at least the permissive percentage P ( precomp ). . In some implementations, for example, P ( precomp ) can be 10%, 20%, 30% or 40%.

As described above, any one of these aberration measures may belong to any one of five reference points P1, ... P5, or some other predetermined reference point, or an average of values at the reference points, or , Averaged over the wavefront.

In some embodiments, precompilator 200 may also compensate for aspherical aberration, eg, first or higher order aberration. In some cases, it can also perform visualization of off-axis light.

In some implementations, the precompilator 200 may be of a different type, while not increasing the RMS wavefront error by more than 0.075, or by maintaining a strel ratio above S ( precomp ), for example having a value of 0.8. Show off aberrations.

In some implementations, the precompilator 200 can increase the radius rb of the beam exiting the precompilator 200 to a value above rb = rb ( precomp ), where rb ( precomp ) is an example. For example, it may be 5 mm or 8 mm.

Some of these functions can be reached by including one or more movable lenses into the precompilator 200. The position actuator can move the movable lens or lenses while varying the distance between some of the lenses of the precompilator 200.

In an implementation with one movable lens, the movable lens of the precompilator 200 can move the focal plane or focal point of the laser delivery system 1 along the optical axis by 0.3 to 4.0 mm. In some other implementations, by 0.5 to 2.0 mm.

In some implementations, when at least one of the strel ratios S ( low ) at the reference points P1,... P5 described above when the movable lens is in the center position is moved, S = S ( moveable ) Possible lenses can be moved to increase the strel ratio S ( low ) to a value above S = S ( moveable ). S ( moveable ) can be 0.6, 0.7, 0.8 or 0.9.

In some embodiments, the movable lens can be moved to change the strel ratio S in the range of 0.6 to 0.9. In other implementations, it may range from 0.70 to 0.85.

Because the precompilator 200 is located in front of the XY scanner 300 or other beam expander, the beam radius is still small. Thus, the movable lens can be small. And since the movable lens is small, the position actuator can move the lens quite quickly while allowing quite a quick change in the depth of focus. This property results in more depth scanning or Z scanning speed in these embodiments, and can generally produce a Z scanning speed similar to a faster XY scanning speed.

In some general existing systems, aberrations are dominantly compensated by optical means, for example lenses. The presently described movable lens precompilator 200 can use a fast movable lens or lenses to perform this function well. In particular, when the laser beam is scanned with the XY scanner 300, the movable lens or lenses can be moved at significantly higher speeds so that the aberrations associated with XY scanning are compensated to the desired level.

7A shows that such an improvement may be useful when the traversing surgical cut 206 is performed while tracking the contact surface of the substantially flat or curved patient interface 208. The speed of the small movable lens enables Z scanning to be performed at the speed required by XY scanning, forming the desired bent cut.

In some implementations, the curvature or radius of the curved target line or curved cut can be less than 1 mm, 10 mm, and 100 mm.

7B illustrates another useful aspect of high Z scanning speed. The focal plane of most optical systems is somewhat curved. It is desirable to create a substantially straight transversal cut, so that if it does not track the curvature of the focal plane, the depth of focus is simultaneously readjusted continuously with fast transverse XY scanning to compensate for the curvature of the focal plane. Need to do. For example, for a flat cut or radial cut with a raster scan pattern, the change in radial or XY coordinates can be quite fast. Fast Z scanning speed in this procedure can help to form the desired straight cut.

As a result, high Z scanning speeds can also be useful for quickly performing some surgical procedures, such as corneal procedures.

In some implementations, the movable lens precompilator 200 can vary the depth of focus of the laser delivery system having an axial speed at least 5% of the maximum transverse scanning speed of the focal point. In some implementations with an axial speed, it is at least 10% of the maximum transversal scanning speed of the focal point. In other implementations with an axial speed, it is at least 20% of the maximum transversal scanning speed of the focal point.

In some implementations, the movable lens precompilator 200 can vary the Z coordinate of the focus by 0.5 to 1 millimeter at Z scanning time.

In some implementations such a Z scanning time may be in the range of 10 to 100 nanoseconds, 100 nanoseconds to 1 millisecond, 1 millisecond to 10 milliseconds, and 10 milliseconds to 100 milliseconds.

In some implementations the movable lens of the lens group is movable in the Z movement range, reducing the first aberration measure by at least the movable percentage P ( movable ). Here, the first measure of aberration is the spherical aberration coefficient (a ₄₀₎ ), The RMS wavefront error ω and the focal radius r _f , and the percentage P ( movable ) may be 10%, 20%, 30% and 40%.

In some embodiments the movable lens of the lens group is movable in the Z movement range to increase the strel ratio S by at least the movable percentage P ( movable ), wherein the movable percentage P ( movable ) is 10%, 20%, 30% and 40%.

In some implementations, the movable lens precompilator 200 is substantially independent by moving any of the numerical aperture NA of the laser delivery system 1, the Z depth of focus, the aberration measures, and the movable lens. It is possible to vary the beam diameter. In other words, moving the movable lens can change any one of the four such features of the laser delivery system 1 without changing the other two features. These embodiments provide for contemplated control for the operator of the embodiment.

Some of the functions of the precompilator 200 are called beam steering or beam extension. Thus, blocks with similar functionality in some existing systems are called beam conditioners or beam expanders.

In some embodiments precompilator 200 comprises only one lens to achieve the above functionality.

In some embodiments precompilator 200 comprises two to five lenses to achieve this function.

FIG. 8A illustrates three lens embodiments of the precompilator 200, including a lens 221, a lens 222, and a lens 223.

FIG. 8B shows three lens embodiments of a movable lens precompilator 200 'including a lens 221', a movable lens 222 'and a lens 223'.

8C shows a four lens embodiment of a precompilator 200 ″ including lenses 231-234.

8D illustrates four lens spheres of a movable lens precompilator 200 '' ', including a lens 231', a movable lens 232 ', a lens 233' and a lens 234 '. An example is shown.

Tables 2-4 show various three lens implementations of the precompilators 200, 200 'of FIGS. 8A and 8B. Embodiments of the precompilator 200 can be implemented using thin lenses. Thus, the lenses can be described with respect to the distance from the next lens and the refractive power of the individual lenses.

Table 2 also shows three fixed lens embodiments of the precompilator 200 shown in FIG. 8A. In Table 2, row 1 shows the lens number, row 2 shows the refractive power measured with a diopter (Di (i = 1, 2, 3)), and row 3 shows the lenses i and i + 1. ) Shows the distance di (i = 1,2).

TABLE 2 for FIG. 8A

Table 3 shows two movable lenses 222 ′, 223 ′, showing lens spacings diA, diB in two configurations A, B in rows 3 and 4, as in FIG. 8B. A possible implementation of the precompilator 200 'with The lens spacing di can vary continuously between diA and diB.

TABLE 3 for FIG. 8B

Table 4 shows that in various implementations, the above parameters Di, di can estimate values at large intervals, depending on many design considerations, for example, different beam sizes and available space. Some of the parameters of this embodiment can be connected to the embodiments of Tables 2 and 3 by scaling the refractive power with a scaling factor and the distance l / a with the corresponding scaling factor. Moreover, the refractive power can be further varied by the tolerance factors t1 to t3 to allow for differences in tolerances and design implementations. This relationship is summarized in Table 4:

TABLE 4 for FIGS. 8A and 8B

In some implementations the scaling factor a may be in the range of 0.3 to 3, and the tolerance factors t1, t2, t3 may be in the range of 0.8 to 1.2.

Similarly, Table 5 shows various four lens implementations of the precompilator 200 ″ where the lenses 231, 232, 233, 234 are fixed, as shown in FIG. 8C.

TABLE 5 for FIG. 8C

Table 6 shows a four lens implementation of the precompilator 200 '' 'of FIG. 8D, with one movable lens 232'.

TABLE 6 for FIG. 8D

As in the three lens implementation, the parameters of the four lens precompilators 200 '', 200 '' 'can estimate values over a wide range. Again some parameters of this implementation can be related to each other by scaling factors a, l / a, t1, t2, t3 and t4, similar to Table 4, respectively. The scaling factor (a) may be in the range of 0.2 to 5, and the tolerance factors (t1, ... t4) may be in the range of 0.7 to 1.3.

In other embodiments, other combinations and ranges may be employed. Within this range, many embodiments of the laser delivery system 1 are possible because the system can be optimized for many different functions, resulting in different choices. Design compromises and optimization constraints can be derived in many implementations, each having advantages. Many possibilities are illustrated by the range of parameters in Tables 2-6 above.

In one movable lens implementation of the precompilator 200 ', the moving lens can change one of the characteristics of the laser system substantially independently. These parameters include the Z focal depth, numerical aperture (NA), any one of the aberration measures, and the diameter of the exit beam. For example, such implementations allow the operator to change, for example, the numerical aperture of the laser delivery system 1 without changing the Z focal depth.

In some implementations precompilator 200 has two independently moving elements. This implementation allows the operator to maintain a fixed aberration while simultaneously controlling two features of the laser beam such as, for example, the numerical aperture NA and the beam diameter.

9 shows an embodiment of the laser delivery system 1 ′, with the Z scanning function of the various optical blocks highlighted. In particular, the laser engine 100 generates a laser beam, which is received by the first Z scanner 250. The first Z scanner 250 receives the laser beam from the laser engine 100 and scans the focal point of the laser delivery system 1 ′ over the first Z interval along the optical axis of the laser delivery system 1 ′. The beam emitted by the first Z scanner 250 is received by the XY scanner 300, which scans the laser beam in a direction substantially transverse to the optical axis of the laser system. The emitted XY scanned laser beam is then received by the second Z scanner 450, which scans the focus of the laser system over a second Z interval along the optical axis of the laser system.

In some embodiments, the first Z scanner 250 is configured such that the first Z interval is suitable for the corneal surgical procedure, and the second Z scanner 450 is configured such that the second Z interval is suitable for the anterior segment surgical procedure.

In some embodiments, the first Z interval is in the range of 0.05 to 1 mm and the second Z interval is in the range of 1 to 5 mm.

In some embodiments, the first Z interval is in the range of 1 to 5 mm and the second Z interval is in the range of 5 to 10 mm.

In some embodiments the first Z scanner 250 is configured to scan the focus over a first Z interval of 0.05 mm to 1 mm at a first scanning time. The first Z scanning time may be in one of the ranges of 10 to 100 nanoseconds, 100 nanoseconds to 1 millisecond, 1 millisecond to 10 milliseconds, and 10 milliseconds to 100 milliseconds.

In some embodiments second Z scanner 450 is configured to scan the focus over a second Z interval of 1 mm to 5 mm at a second scanning time. The second Z scanning time may be in one of the ranges of 10 milliseconds to 100 milliseconds and 100 milliseconds to 1 second.

In some embodiments the first Z scanner 250 is configured to vary the aperture of the laser beam by at least 10%.

In some embodiments the second Z scanner 450 is configured to vary the aperture of the laser beam by at least 10%.

In some embodiments the first Z scanner 250 is configured to vary the aperture of the laser beam by at least 25%.

In some embodiments the second Z scanner 450 is configured to vary the aperture of the laser beam by at least 25%.

10 shows a summary table of the many variations of the elements described above. As shown, some implementations include one Z depth scanner, one Z depth scanner in front of XY scanner 300, one Z depth scanner behind XY scanner 300, and one in front and one behind XY scanner 300. Can have two Z depth scanners.

In addition, some implementations have two NA controllers: one NA controller in front of the XY scanner 300, one NA controller in front of the XY scanner 300, one NA controller in front of the XY scanner 300 and one in front of and one behind the XY scanner 300. Can have

Here, Z scanners and NA controllers quite generally refer to a single lens or group of lenses, which can change the Z depth and numerical aperture (NA), respectively. In some cases, such a modifier can be activated or controlled by a single electric actuator, which causes the lenses of the modulator to move simultaneously to change the Z depth and NA of the beam.

Both the Z scanner and the NA controller may be housed in the first Z scanner 250 and the second Z scanner 450 of FIG. 9. In some cases the corresponding optical elements are separate, and in other implementations the Z scanner and NA controller housed in the same Z scanner block 250 or 450 may share one or more lenses, movable lenses or electric actuators.

As shown in FIG. 10, zero Z scanners and one or two NA controllers operate at a fixed Z depth, but can control the NA during XY scanning.

One Z scanner and zero NA controllers can perform Z scanning.

One Z scanner and one or two NA controllers may perform control of NA in addition to Z scanning.

When combined with one or two NA controllers, the two Z scanners can perform Z scanning at two speeds and also control the NA.

In addition, lensless optical elements may be used in some embodiments, such as variable apertures and pupils.

In addition, most of the 16 combinations shown may be further configured to exhibit a selected aberration, for example spherical aberration.

FIG. 10 shows that various system features, such as Z depth, numerical aperture (NA), and aberration of the beam, represented by aberration measures such as Strelby (S), can be independently controlled or adjusted from each other. These embodiments provide great control and accuracy to the operator of the laser delivery system 1.

In similar embodiments, such dual beam conditioning can be performed for other pairing of beam characteristics. For example, a similar table with 4x4 = 16 pairing can be generated for the beam diameter controller and the aberration controller. Here, zero, one or two aberration controllers can be paired with zero, one or two beam diameter controllers in all possible combinations.

The list of beam features includes the Z depth of focus, numerical aperture (NA), beam radius, and any aberration measures such as strel ratio (S), focal radius (r _f ), RMS wavefront error (ω) and spherical aberration measure. (a ₄₀ ).

3. XY  Scanner 300

The XY scanner 300 may receive the beam emerged from the precompilator 200, which has passed through some intermediate optical elements, directly or indirectly. The function of the XY scanner 300 is to scan the beam received from the precompilator 200 in a direction substantially transverse to the optical axis of the laser delivery system 1. In various embodiments, the "crossing" direction is not necessarily perpendicular to the optical axis, but may include any direction that creates an actual angle with the optical axis.

In some embodiments the XY scanner 300 emits a scanning laser beam, the scanning laser beam propagating through the laser delivery system 1 and reaching the surgical area is from zero to a maximum of XY scanning range of 5-14 mm. Scan in the direction of traversal. In some implementations the maximum of the XY scanning range is between 8 and 12 mm.

11A shows that XY scanner 300 may include an X scanner and a Y scanner. In some existing designs, each of the X scanner and Y scanner includes one mirror: a single X scanning mirror 310 and a single Y scanning mirror 320. In this design the beam deflected by the X scanning mirror 310 strikes the Y scanning mirror 320 at different points along the orientation of the X scanning mirror 310. In particular, when the X scanning mirror 310 is in position 310a, the incident beam 331 is reflected as beam 332a, while when the X scanning mirror is rotated in position 310b the incident beam is beam ( 332b).

These two beams 332a and 332b strike the Y scanning mirror 320 at different positions and thus even two different beams 333aa and 333ba respectively for the fixed Y scanning mirror 320 at position 320a. Will give rise to this. Also worse, when the X scanning mirror 320 itself is rotated from position 320a to position 320b, the two incident beams 332a, 332b are two additional reflected beams 333ab, 333bb. This results in all four beams 333aa, 333ab, 333ba, 333bb propagating in different directions.

The problem can be characterized with respect to the concept of pivot point. One concept of the pivot point of the scanning optical element may be the point at which all rays exiting from the optical scanning element pass substantially. This concept is analogous to the focal point of non-moving refractive elements, as applied to moving optical elements, for example scanners.

Using this term, the above problem can be traced back to the X scanner pivot point 315X fixed to the X scanning mirror 310 itself in FIG. The emitted scanned beam will appear for successive optical elements as coming from a single pivot point 315X on the X scanning mirror 310 and thus propagating at a wide range angle. This divergence of the two mirror designs can lead to some different form of unwanted aberrations.

FIG. 11B shows an existing three mirror XY scanner 300 ′, and the X scanner 310 includes two mirrors 311, 312 and addresses this problem. For clarity, the mirrors are shown from the side. In this design, the X scanning mirrors 311 and 312 perform the X scanning function in a cooperative manner. As shown in FIG. 11B, as the first X scanning mirror 311 changes its orientation from 311a to 311b, the second X scanning mirror 312 can be rotated in a cooperating manner from 312a to 312b. This cooperative scanning rotation enables the deflected beams 332a and 332b to pass through the pivot point 315X in two rotational steps, which are raised out of the X scanning mirrors.

Since the X scanner pivot point 315X has been raised from the X scanning mirror itself, the position can be adjusted. In the design of FIG. 11B, X scanning mirrors are designed to position pivot point 315X substantially to Y scanning mirror 320. In this design the problem of the X scanner 310 in FIG. 11A is substantially solved and the corresponding aberrations are greatly reduced.

However, even this design has a similar problem to that of FIG. 11A only considering the Y scanning mirror 320. In the design of FIG. 11B, the Y scanner pivot point 315Y is still fixed to the Y scanning mirror.

The entrance pupil of the optical system is an image of an aperture stop when viewed from the front side of the system. The exit pupil is the image of the aperture aperture in the image space. In optical systems with multiple groups of lenses, the position of the entrance pupil and exit pupil is often carefully adjusted. In many designs, the exit pupil of one lens group matches the entrance pupil of the next lens group.

For the XY scanner 310, the pivot point may be considered an exit pupil. In some embodiments such exit pupils coincide with incident pupils of the next lens group, such as Z scanner 450. However, the entrance pupil of the lens group may exist inside the physical boundary of the lens group, and the scanner block may not be disposed. In this case the scanner block is preferred to be outside the physical boundaries of the scanner block, at a position where the pivot point can be arbitrarily selected.

11C shows four mirror designs that address this problem. In XY scanner 300 ″ X scanner 310 again includes X scanning mirrors 311, 312. However, the Y scanner also includes two Y scanning mirrors 321, 322.

XY scanner 300 ″ removes Y scanner pivot point 315Y from the Y scanning mirror. Thus, the XY scanner 300 '' can control the Y scanner or exit the pivot point 315Y to a predetermined position. An embodiment is to move the Y scanning exit pivot point 315Y to the incident pupil 350 of a continuous lens group. In some implementations X pivot point 315X may also be moved to the same location.

Another aspect of this design is substantially independent of (i) the angle (α) between the optical axis of the laser delivery system 1 and the emitted and scanned beam at a distance d from the optical axis. Characterized by being able to control the location of impacting the incident pupil of the continuous optical element. Because of the approximate independence of this control, the XY scanner 300 '' can include a peripheral area of the surgical area, control not only astigmatism and coma in the peripheral area, but also provide a scanning beam with minimized aberrations. have.

Some implementations of the XY scanner 300 '' 'include only one X scanning mirror 310 and one Y scanning mirror 320, each of which is in the form of "fast steering". The individual fast steering mirrors can be angular motion around two axes of rotation. A pair of these fast steering mirrors can also control the beam position and beam angle in a plane transverse to the optical axis.

In some implementations the XY scanner 300 '' 'is configured to scan the laser beam over an XY scanning range with a maximum greater than 5 millimeters and 15 millimeters short in the focal plane of the laser system.

In some implementations the X pivot point generated by the first and second XY fast steering mirrors and the Y pivot point generated by the first and second XY fast steering mirrors coincide.

4.Z Scanner (450)

As described above, the ophthalmic surgical system is configured to perform lens surgery or anterior segment surgery by having a design that allows scanning of focus over an interval much larger than the interval scanned in the corneal procedure. In some implementations, Z scanning is performed over a Z scanning path within a Z scanning range of 5 mm to 10 mm or 0 mm to 15 mm. (Through this application, the term "scanning within a range of x mm to y mm") means that the initial value is x, including all scanning paths that do not extend over the entire scanning range. Refers to a scanning path of greater than or equal to mm and whose final value is less than or equal to y mm.)

Here, it is recalled that the "X, Y, Z" arrangement means throughout the implementation in a broad sense. Z generally represents the optical axis, which may be present in proximity to the geometric axis. However, the Z direction inside the target tissue, for example the eye, may not be completely parallel to the optical axis of the laser delivery system 1. Any compromise axis between these two may also be called in the Z direction. Also, the X and Y directions are not necessarily perpendicular to the Z axis. They can represent any direction that makes an actual angle with the Z direction. In addition, in some implementations, the radial coordinate system may be more suitable for describing the scanning of the laser delivery system 1. In this implementation, XY scanning represents any scanning that is not parallel to the Z axis, parameterized by appropriate radial coordinates.

1 shows that some implementations of the laser delivery system 1 achieve this challenging Z scanning range by including a first beam expander block 400 and a movable beam expander block 500 in the Z scanner 450. do. In various implementations, the first beam expander block 400 may be a movable block or a fixed block. The distance between the first beam expander block 400 and the movable beam expander block 500 can be adjusted by, for example, a position actuator.

As already shown in FIGS. 2A and 2B, as the focal point is moved away from the optimal position in the target tissue, the aberration increases. Such aberrations are generally referred to as "geometric aberrations" because they can be understood from tracking geometric rays and can be oriented from a finite limit of lenses. Such geometric aberrations can be limited by making the numerical aperture of the Z scanner 450 small. As such, geometric aberrations depend on both numerical aperture (NA) and the Z focal depth.

In addition, as the numerical aperture NA is reduced, the second source of aberration is caused by the wave nature of the light. This aberration results in a so-called "diffraction aberration." This second type of aberration increases the focal radius as the numerical aperture is reduced.

12A and 12B show geometric and diffraction aberrations in the anterior segment of the eye as a function of the aperture size of the Z scanner 450, characterized by the focal radius r _f , one of the above aberration measures. . Since the diffraction aberration decreases while the geometric aberration increases with the aperture size, the total aberration, defined as the sum of these two aberrations, exhibits an optimal minimum value at the optimal aberration and the corresponding optimal numerical aperture (NA _opt ).

A useful definition here connects the numerical aperture (NA) and the aperture size: NA = n * SinArTan (opening size / (2 * focal length)), where n is the refractive index of the material on which the image is formed.

These curves are for a specific Z focal depth, 1 mm Z focal depth in FIG. 12A and 8 mm focal depth in FIG. 12B. Since the geometric aberrations differ at different Z focal depths, the minimum value of the total aberration curve and thus the optimal aperture size and optimal numerical aperture (NA _opt ) of the overall system depends on the Z focal depth: NA _opt = NA _opt (z). In particular, the optimum aperture size and NA _opt decrease from 32 mm to 25 mm in this particular case as the Z focal depth increases from 1 mm to 8 mm for increasing Z focus depth. Thus, laser delivery systems intended for use in both corneal and lens surgery require covering a wide range of apertures and corresponding NA ranges. This requirement takes significant design effort.

As will be explained further below, FIGS. 12A and 12B show a wide and flat optimum for a generally corneal Z focal depth of 1 mm, while aberrations represent a narrower and clearer minimum for Z focal depth for lens surgery. It also shows that.

The aberration can also be characterized by the other three aberration measures (S, ω, or a ₄₀ ), all yielding curves representing an optimal value. Any of the above four aberration measures may correspond to any of the five reference points P (1), ... P (5) described above, or across some or all of these reference points. It may be an average taken or may correspond to other reference points.

In some implementations, over a wide range of Z focal depths, the aperture size and corresponding NA can be adjusted to the substantially optimal numerical aperture (NA _opt (z)) while minimizing the total aberration, as measured by the aberration scale. This function allows a strong reduction of the total aberration. Here, as before, the aberration may be measured by one of the four aberration scales r _{f ,} S, ω, or a ₄₀ at any one of the five reference points P1, ... P5 above. Can be. The optimum aberration corresponds to the maximum of the strel ratio S or the minimum of the aberration measures (r _{f ,} ω, or a ₄₀ ).

In some other implementations, the second block of the Z scanner 450 is not movable and the numerical aperture is adjustable accordingly, in which some optimal aberration cannot be reached or design considerations indicate that an aberration spaced from the optimal value should be used. Compared to the aberration measure of a substantially identical laser system that does not, the movable beam expander block 500 can still reduce the value of the aberration measures r _{f ,} ω, or a _{40 by} at least P ( MovableExpander ) percentage, or , Correspondingly, increase the value of the strel ratio S by at least P ( MovableExpander ) percentage. In some implementations P ( MovableExpander ) may be 20%, 30%, 40% or 50%. Here, as before, the aberration measures r _{f ,} S, ω, or a ₄₀ may be measured at any one of the five reference points P1, ... P5.

In some implementations a laser system with a Z scanner 450 with an adjustable numerical aperture (NA) for a substantially identical laser system without an adjustable numerical aperture, where the Z scanner has a strel ratio (S) below 0.8. Increasing the strel ratio above 0.8

Further design attempts not only minimize total aberration at a fixed Z focal depth by adjusting the laser delivery system to the optimum aperture size and corresponding numerical aperture (NA _opt (z)), but at least Z dependent as the Z focal depth is scanned. It is to keep the system close to the optimum numerical aperture NA _opt (z). In general practice, the optimum numerical aperture decreases as the depth of focus increases.

In order to deal with the change in the optimum aperture as the Z focal depth is scanned within the Z scanning range, the implementation of the laser delivery system 1 is substantially independent of the separation of the Z scanner 450 from changing the Z focal depth itself. As a given parameter, it has the ability to change the numerical aperture NA (z).

As of present Z focal depth and numerical aperture (NA), an implementation in which two quantities can be controlled substantially independently, generally achieves this form with a pair of control parameters. Embodiments include the pairing of the controllable distance between the first beam expander block 400 and the movable beam expander block 500 and the position of the lens movable in any one of these blocks, which is coupled to the secondary optical controller. Can be adjusted by Another embodiment includes two movable lenses in any combination in the two blocks of the Z scanner 450. It is recalled that the first beam expander block 400 can be implemented as a fixed block or a movable block.

In some implementations, the numerical aperture NA may be adjusted in order of the optimum numerical aperture value NA _opt (z) while calculating the order of the optimal total aberration value in the order of the Z focal depth as the Z focal depth is scanned.

As before, the optimal total aberration can be obtained by the maximum of the strel ratio S or by the minimum of any of the aberration measures r _f , ω, or a ₄₀ . The Z scanning range can be, for example, 5 to 10 mm or 0 to 15 mm. The Z focal depth is scanned at radius r1 = 0 mm or r2 = 3 mm, or at some other radius r, or at a variable radius r (z), bounded by, for example, r <3 mm. Can be.

Table 7 shows an example in which the second row describes the scanning of the Z focal depth within the Z scanning range of (-0.14 mm, 11.65 mm) in the eye target tissue and the third row shows the value of the corresponding NA _opt (z). Shows. Implementation of the Z scanner 450 may be able to adjust the Z focal depth in this range and adjust the numerical aperture NA to the optimal value NA _opt (z) at this focal depth.

[Table 7]

In some other embodiments, the Z focal depth can be scanned within a Z scanning range of 0 mm to 10 mm. The numerical aperture during the scan may vary within the range of 0.4 to 0.1, and in some other embodiments may be 0.35 to 0.15.

FIG. 12C shows a similar order of aberration curves corresponding to the order of Z focal depths of 8 mm, 4 mm, 2 mm and 0 mm, showing the order of the corresponding optimal numerical aperture NA _opt (z).

12D clearly shows the optimum numerical aperture NA _opt (z) as a function of the corresponding Z focal depth.

As explained above, the separate adjustability of the numerical aperture NA and the Z focal depth generally requires two independently adjustable control parameters. However, some implementations may not provide separate and independent adjustment of Z and NA. Instead, for all Z focal depths, these implementations automatically adjust the numerical aperture to an optimal value (NA _opt (z)) or at least in the vicinity of NA _opt (z), without a separate NA adjustment step by the operator. For example, NA tracks NA _opt (z) in P ( track ) percentages, where P ( track ) can be 10%, 20% or 30%.

This implementation may only have a single, integrated adjustable controller. In the described embodiment, this integrated controller may indicate to the user of the system controlling the Z focal depth in the target area. However, the controller may comprise a combined aperture adjuster, which simultaneously adjusts the numerical aperture NA without the need for a separate tuning step performed by the user of the laser delivery system 1 to provide NA _opt (z). To track.

In some implementations, adjusting the distance between the first beam expander 400 and the movable beam expander 500 can perform this function as appropriate. In other implementations, a single movable lens can provide this type. In yet another implementation, a combination of the two adjusting devices may be employed.

These implementations provide a simplified control function for the operator of the laser delivery system 1. Since it is a design effort to achieve this single integrated control function, some implementations may incorporate this integrated in combination with other blocks, eg, precompilator 200, XY scanner 300, and objective 700. Perform control functions.

In some implementations where optimal gross aberration values may or may not be achieved for various design considerations, the numerical aperture NA may be adjusted in the order of numerical aperture values in the order of the Z focal depth along the Z scanning path within the Z scanning range. Z scanner 450 can reduce total aberration by at least P ( scan ) percentage for laser systems that do not have an adjustable numerical aperture (NA). In some implementations P ( scan ) can be 20, 30, 40, or 50 percent.

As before, the total aberration may be characterized by any one of the previously introduced aberration measures (r _f , ω, or a ₄₀ ). Equally, the reduction in aberration can be characterized by an increase in the corresponding strel ratio (S). The Z scanning path can be a path parallel to the Z axis at radius R from the optical axis or Z axis of the laser system. In some implementations the Z scanning path may be located between a radius r1 = 0 mm and r2 = 3 mm from the optical Z axis.

Total aberration can be measured in several different ways. The total aberration may represent the maximum or minimum value of the total aberration averaged over the Z scanning path or the total aberration along the scanning path. The reduction in total aberration represents one of these possibilities.

In some implementations, the numerical aperture NA may be adjusted from the first value when the corneal procedure is performed to the second value when the anterior segment procedure is performed. In some implementations the first value is in the range of 0.2 to 0.5 and the second value is in the range of 0.1 to 0.3. In some other implementations the first value may be in the range of 0.25 to 0.35 and the second value may be in the range of 0.15 to 0.25.

This implementation of the Z scanner 450 differs from existing corneal laser delivery systems in several other ways, including the following.

1. In corneal laser delivery systems, numerically, the numerical aperture does not change during the Z scan of focal depth, which is required to ensure the simplicity of the design. This design is satisfactory for corneal surgery because the total aberration induced by a typical 1 mm Z scan is not a serious limiting factor of the accuracy of the corneal laser delivery system. On the other hand, the implementation of the laser delivery system 1 has a variable numerical aperture NA to keep adjusting the opening to the optimum opening over a wide range of surgical Z intervals, for example 5 to 10 mm. Of course, this is achieved by the form of numerical aperture NA which is adjustable substantially independently from the Z focal depth.

2. Also, a typical existing corneal system has a Z scanner as part of a complex implementation of objective 700, or in objective 700, whereas current Z scanner 450 is located in front of objective 700. Objective 700 here represents the final lens group of the laser delivery system 1 located in a functional and mechanical housing separate from the functional and mechanical housings of the Z and XY scanners. The term functional and mechanical housing does not refer to the entire housing of the delivery system, the design of which may be dictated by ergonomics or appearance considerations, but means a housing that holds the lenses together to perform the actual optical function. The objective 700 of this embodiment is generally located in the optical path after the XYZ scanning beam emitted by the Z scanner 450 is deflected by the mirror 600.

3. FIGS. 12A and 12B illustrate additional trials in the design of a lens surgical optical system. Visibly, the total aberration represents a wide and flat optimal area for a typical corneal Z focal depth of 1 mm, so that without any significant deterioration in focal size, (i) system parameters can be optimized for other considerations, ( Ii) A wide range of Z scanning ranges can be used, and (iii) less precise fine tuning of system parameters is required. On the other hand, for a lens surgical system, the focal size decreases quickly when (i) the system parameters are optimized for other considerations, (ii) a wide range of Z scanning ranges are carried out, and (i) the system parameters are finely tuned less precisely. do.

In a further aspect of an embodiment of the Z scanner 450, a laser delivery system comprising a visible observation optical sub-system or an imaging subsystem is connected to any one of these subsystems coupled via a mirror 600 to a laser delivery system. It is recalled that it has an associated beam. The mirror 600 may be, for example, a dichroic mirror. In a typical surgical system, objective 700 refers to a group of lenses positioned behind mirror 600 in the optical path.

Z scanner in front of mirror 600 and separated from objective 700 because objective 700 is substantially in direct contact with the target tissue, for example the patient's eye, and because the weight of objective 700 is a critical factor. Implementing 450 is an important design consideration. Thus, minimizing the weight or mass of the objective 700 allows the implementation of the laser delivery system 1 to provide a reduced pressure on the eye. Since this pressure deforms the eye itself and thus reduces the accuracy of the surgical procedure, a design that reduces pressure on the eye significantly increases the accuracy of ophthalmic surgery.

Tables 8 and 9 show a range of some related parameters for various embodiments of the first beam expander block 400 and the movable beam expander block 500. The beam expander blocks may each have two to ten lenses, and in some embodiments have three to five, which are configured to perform the above functions.

Table 8 shows five lens embodiments of the first beam expander block 400 using industry standard conventions, describing a group of thick lenses for individual surfaces. The first beam expander block 400 can include lenses 411, 412, 413, 414, 415 having parameters in the following ranges (indicated by parentheses).

[Table 8]

In some embodiments, the first beam expander block 400 is continuously from the incidence side facing the XY scanner 300: a first group of lenses having positive refractive power, a meniscus having a block surface facing the incidence side And a second lens having a concave surface facing the lens and the incidence side.

Other implementations have a scale factor (a), having five scaled lenses, having a curvature of the second row multiplied by a, having a distance of the third row multiplied by 1 / a, and a constant refractive index n. It relates to implementation of Table 8. The scale factor can estimate a value between 0.3 and 3.

Table 9 shows four lens embodiments of the moving beam expander block 500, including lenses 511, 512, 513, 514, with parameters in the following ranges:

TABLE 9

Some implementations of the movable beam expander block 500 may be continuous from the incidence side facing the first beam expander block 400: a meniscus lens having a block surface facing the incidence side, negative with negative refractive power. Lenses and positive lens groups with positive refractive power.

Other implementations have a scale factor (a), having four scaled lenses, having a curvature of the second row multiplied by a, having a distance of the third row multiplied by 1 / a, and a constant refractive index (n). By the implementation of Table 9. The scale factor can estimate a value between 0.3 and 3.

13A and 13B show the embodiments of Tables 8 and 9 in two configurations with different distances between the first beam expander block 400 and the moving beam expander block 500. In some implementations, the moving beam expander block 500 can be moved relative to the first beam expander block 400 by a distance in the range of d = 5-50 mm.

These figures illustrate design considerations of the Z scanner 450 in operation.

FIG. 13A illustrates the case where the movable beam expander block 500 is at a position relatively remote from the first beam expander block 400. In this case, the beam exiting the assembled assembly may be (i) converging rays, (ii) relatively large diameter in the exit pupil (ExP), and (i) fixed focal length objectives near the exit pupil of the Z scanner 450. When positioned, it has a shallower Z depth of focus, and thus (i) a focal point formed by a beam with a higher numerical aperture NA.

FIG. 13B shows the case when the movable beam expander block 500 is closer to the first beam expander 400 than in the case of FIG. 13A. Here, the beam is (i) converging rays, (ii) smaller diameter in the exit pupil (ExP), (iii) deeper Z depth of focus when a fixed focal length objective is located in the exit pupil of the Z scanner 450. , And thus (iii) a focal point formed by a beam with a smaller numerical aperture (NA).

In summary, at a shallower Z focal depth, the focal point is generated by the larger NA beam, while for increasing the Z focal depth, the numerical aperture NA decreases. The relative change in the numerical aperture NA can be optimized by optimizing the position of the incident pupil of the focused objective 700 and the position of the exit pupil ExP of the beam expander blocks 400, 500. Such implementations are an alternative method for optimizing the numerical aperture at evenly different focal depths without the use of the functionality of the precompilator 200.

As described above, the numerical aperture NA can be adjusted extensively with or without the precompilator 200. In the entire laser delivery system 1, the numerical aperture NA controls these blocks by controlling or in combination with the precompilator 200, the first beam expander block 400 or the movable beam expander block 500. Can be adjusted. In practice the actual choice of implementation depends on other higher level system level requirements, for example scanning range, scanning speed and complexity. Implementations with other numerical ranges may also be configured to perform some or all of the functions described above.

14 illustrates a further aspect of the Z scanner 450. Three different feature beams are shown exiting the exit pivot point PP (XY) of the XY scanner 300. Remarkably, all three feature beams are focused by the Z scanner 450 to the incident pivot point PP (O) of the objective 700. The position of PP (O) can be adjusted, for example, by moving the movable beam expander 500.

As described below, a laser delivery system that generates a pivot point PP (O) positioned out of the mirrors of the XY scanner 300 may, for example, have a pivot point PP (O) whose objective 700 is an image. In embodiments present therein, it has a useful structure.

In another embodiment, the XY scanner 300 has an exit pivot point PP (XY) that is further than the distance to the Z scanner 450. In this embodiment, the Z scanner 450 only changes the exit pivot point PP (XY) of the XY scanner 300 to the incident pivot point PP (O) of the objective 700.

In either case, this implementation allows the use of the presence of the intermediate focal plane 451, located between the first beam expander block 400 and the movable beam expander block 500. The presence of the intermediate focal plane 451 is indicated by the focal point of three feature beams consisting of left and right having substantially the same Z coordinate. Conversely, implementations that do not take this intermediate focal plane are not quite suitable for having an adjustable pivot point PP (O).

5. Objective (700)

In some implementations the laser beam emitted by the Z scanner 450 is deflected to the objective 700 by the beam splitter / chromic mirror 600. Through this mirror 600 various auxiliary lights can also be combined into the laser delivery system 1. Auxiliary light sources can include light associated with optical coherence tomography (OCT) systems, illumination systems, and visible observation blocks.

The objective 700 can provide a shared optical path for the auxiliary light to the surgical target area and the XYZ scanned laser beam propagating from the laser engine 100 through the XY scanner 300 and the Z scanner 450. have. In various implementations, the objective 700 may be a group of objective lenses. In some implementations the lenses of the objective lens group do not move relative to each other. As such, objective 700 is an integral part of the Z scanning function, while not contributing to Z scanning in a variable or dynamic manner. In such implementations no lens position is adjusted in the objective 700 to shift the Z focus depth of focus.

Implementations of the objective 700 may control at least one of spherical aberration, coma, and higher order aberration of the surgical pulsed laser beam.

Since the objective 700 guides light of different wavelengths, the implementation of the objective 700 uses a group of chromatic lens groups. The wavelength of the auxiliary light may be in the range of 0.4 micron to 0.9 micron, for example, and the wavelength of the surgical light may be in the range of 1.0 to 1.1 micron. Implementation of the objective 700 maintains chromatic aberration below a predetermined value over a range of wavelengths of light used, for example 0.4 microns to 1.1 microns in the above embodiment.

The weight or mass of the objective 700 is an important consideration. In some implementations the objective is in mechanical contact with the eye of the patient. As such, it exerts pressure on the eye. The pressure can distort the eye from the relaxed configuration, making it difficult to accurately select the target and orient the surgical laser beam.

Moreover, if the patient moves during the surgical procedure, it may be desirable that the objective can move with the least resistance to the patient's movement. Although the weight of the objective can be statically balanced with a spring system or parallel weights, this measure cannot reduce dynamic forces or tube forces. In fact, this force can be increased by this measure. All of these considerations point to the usefulness of reducing the weight or mass of the objective 700.

Numerous methods exist for identifying critical forces and corresponding objective masses for ophthalmic surgical procedures. Reports of various effects on the eye are described, for example, in Determination of Significant Parameters for Eye Injury Risk from Projectiles; Duma SM, Ng TP, Kennedy EA, Stitzel JD, Herring IP, Kuhn F. J Trauma October 2005; 59 (4): 960-4. These papers reported (i) an impact impacting eye corresponding to different forms of damage to the eye, including minor injuries such as corneal abrasions, intermediate injuries such as lens dislocations and severe injuries such as retinal damage. The critical energy value of the impact object was provided. The paper also assigns the probability of damage from (ii) low probability, representing a few percent probability, to medium probability, representing about 50% probability, and high probability, indicating almost certain damage. In addition, the paper categorized the impact scenarios according to the shape of the impact object, the classification by the total impact energy, and the impact energy normalized by the impact area.

This result can be applied in certain cases of eye surgery by looking for perhaps the highest impact damage caused by all failures of the mechanical support system of the objective 700. This failure results in the free fall of the entire objective 700 over a typical vertical path of 20-25 mm, while transferring all of the objective's energy to the eye itself. The critical mass can be calculated from published critical energy values modeling the free fall of the objective according to known physical principles.

The vertical path of this length can come from the following design principle. The objective 700 can be mounted on a vertical sliding stage to provide safe and reliable docking of the laser delivery system 1 by gantry to the eye. Since the vertical gantry accommodates the objective 700 and is located within the vertical movement range, this design facilitates accuracy and force requirements on the gantry. In addition, once the eye is docked, this design allows the eye to move perpendicular to the laser source 100 without interrupting the attachment of the eye to the laser delivery system 1. Such movement may occur due to movement of the operating bed or movement of the patient. The 20 to 25 mm vertical movement range of the objective 700 mitigates efficiently and stably with respect to patient movement and gantry forces within this range.

After all, (i) as there are numerous ways to reduce the mass of the control system and the housing of the objective, the design considerations are that of the optical elements of the objective 700, e. "Optical") affects the critical mass in the sense that the mass defines a lower boundary with respect to the mass of the overall objective, while being much harder, reducing the mass of the lens. In the present system the total mass of the objective may alone be the "optical" mass of the lens 2-3 times.

Some of these criteria yield a clearer definition of the critical mass, while others yield a smooth cross correlation without giving itself a clear definition.

From all possible combinations of classifications (i) to (iii) above, four relatively clear and important definitions of critical mass (MC) can be identified as follows:

(1) MC1-400 grams: Objectives with mass M <MC1 substantially do not take the risk of damage to the patient even in the worst case failure scenario;

(2) MC2-750 grams: in the MC1 <M <MC2 regime, the mass may have a greater than 10% chance of causing some corneal abrasions through total impact energy;

(3) MC3 to 1,300 to 1,400 grams: in the MC2 <M <MC3 regime, the mass may have a 50% chance of causing corneal abrasions in certain impact scenarios; And

(4) MC4 to 3,300 grams: In some impact scenarios, the mass in the range of MC3 <M <MC4 can cause almost certain corneal abrasions and can grow the probability of more than a non-zero medium strength injury.

Of course, all of these probabilities are multiplied by a small probability of the total failure of the mechanical support system of the objective actually occurring. However, extreme measures in ophthalmic applications need to be taken to guide for all imaginable impairment scenarios, but create unexpectedly relevant critical masses.

Thus, the above consideration identifies four critical masses according to clear criteria, relative to the total mass and optical mass of the objective 700. Thus, an embodiment of the objective 700 in which the design process manages to reduce the objective mass below any one of the critical masses MC4, ..., MC1 presents a qualitatively better possibility for a safe surgical procedure. to provide.

The existing objectives of femtosecond ophthalmic lasers have a mass above 5000 grams, which is significantly the largest of these four critical masses. The exception is U.S. Patent Application 20030053219 by Manzi, which describes a lens system alone with an optical mass of about 1000 grams, which alone leads to a total mass of 2,000 to 3,000 grams. Manzi's design is lighter than other existing objectives, while still quite large. This is mainly due to the Z scanner, which is an integral part of the objective, since the lens elements inside the objective are used for Z focus control. Additional mass is required by Manzi for precision machined housings, precision linear guides for the lens and servo motors, all increasing the total mass back to above 5000 grams.

On the other hand, the mass of the various embodiments of the objective 700 can exist in any of the four mass ranges above: 0-400 grams, 400-750 grams, 750-1,350 grams, and 1,350-3,300 grams. The weight can be either optical mass or total mass. For example, in the implementation of objective 700, the lenses may have a mass less than 130 grams. It is feasible to mount these lenses in a precision metal housing for a total assembly mass of 400 grams.

Embodiments of the objective 700 remove this noteworthy mass reduction down to 400 grams, 750 grams, 1,350 grams and 3,300 grams by removing the Z scanning function with a separate Z scanner 450 and housed in a separate functional or mechanical housing. To achieve. The term “funtional or mechanical housing” herein may result in the positioning of the separate Z scanner 450 in the same general container as the objective 700 as a whole, while non-functional design considerations may occur. Reference is made to the fact that it does not serve an optical function or a mechanical purpose.

In some embodiments, the mass of the objective 700 can be reduced by a P ( mass ) percentage compared to similar objectives, which performs at least part of the dynamic Z scanning function by adjusting the optical characteristics of the objective 700. This feature can be an entire Z scanner 450 integrated into the objective 700 or a movable beam expander block 500 integrated into the objective 700 or one or more movable scanning lenses integrated into the objective 700. P ( mass ) can be 10%, 50% or 100%.

Another related aspect of the objective 700 and the corresponding design of the surgical laser system 1 have been described in relation to FIG. 14, where embodiments of the Z scanner 450 are directed to the incident pivot point of the objective with the XYZ scanned laser beam. It is shown that it can be focused to (PP (O)). As the beam converges towards this internal pivot point PP (O), embodiments having an incident pivot point PP (O) inside the objective 700 may have a much reduced beam over a large portion of the optical path. In the end, a beam with a reduced beam radius rb can be controlled by smaller lenses, resulting in a significant reduction in the overall mass of the objective 700.

Implementation of the objective 700 according to the above design point of view is summarized in Table 10 and shown in FIG. 15. Implementation of the objective 700 includes a first lens group that receives the surgical pulsed laser beam from the Z scanner 450 and a second lens group that receives the surgical pulsed laser beam from the first lens group and focuses the surgical laser beam into the target area. Include.

Table 10 shows the objective 700 of FIG. 15 in more detail through surfaces 1-16. Objective 700 has nine lenses L1-L9 and interacts with patient interface 800 through surface 17. As before, the brackets indicate a range and the corresponding parameter can be estimated. (Surface 1 and surface 2 define a doublet of lenses L1 / L2, surface 8 and surface 9 define a doublet of lenses L5 / L6, instead of 18 To 16.)

TABLE 10

In other implementations, different numbers of lenses can be used with different parameter ranges, which relatively satisfies the above design considerations.

In some implementations, the objective 700 may be described with respect to a lens group. For example, the objective 700 includes a first lens group that receives the XYZ scanned laser beam from the Z scanner 450, and a second lens group that receives the laser beam from the first lens group. The second lens group comprises a first lens having a refractive index in the range of 1.54 to 1.72, an incidence surface having a curvature in the range of 37.9 to 65 1 / m and an exit surface having a curvature in the range of -15.4 to 5.2 1 / m. can do. In addition, the second lens group is also separated from the first lens by a distance in the range of 0 to 6.5 mm, an incident surface having a refractive index in the range of 1.56 to 1.85, a curvature in the range of -55.1 to -21.8 1 / m, and 11.4. And a second lens having an exit surface having a curvature in the range of from 26.8 to 1 / m. The objective 700 may emit a laser beam through the second lens to the patient interface 800.

In some implementations, the effective focal length of the objective 700 is less than 70 mm.

In some embodiments, the distance from the objective 700 to the patient interface 800 is less than 20 mm.

In some designs the curvature of the focal plane of the laser delivery system 1 is greater than 20 1 / m.

Numerous other implementations of the overall surgical laser system 1 and the objective 700 are also represented throughout this application by using commercially available optical design software packages such as Zemax from Zemax Development Corporation or Code V from Optical Research Associates. It can be created to adhere to design principles.

6. Overall system optical performance

In various implementations, the parameters of the subsystems, the precompilator 200, the XY scanner 300, the Z scanner 450, and the objective 700 may be optimized in an interdependent manner, such that the entire laser delivery system ( The optical performance of 1) can exhibit properties that are particularly useful for ophthalmic surgical applications, for example.

Tables 11a and 11b summarize the optical performance of the overall laser delivery system 1 in the first and second implementations with respect to Strelby S and numerical aperture NA. Again optical performance is characterized at reference points similar to the reference points P1, ... P5. Tables 11a and 11b show configurations A, B, C, which transmit a laser beam to the center of the cornea (A), the cornea's periphery (B), the lens's center (C) and the lens's periphery (D), respectively. The optical performance of the laser delivery system 1 with the components in D) is shown. These reference points represent surgical volume, associated with attempts to perform ophthalmic surgery on the lens.

Tables 11a and 11b show the radial coordinates of the reference points with specific values. However, in other embodiments NA and S estimate values in the same respective range of particular radial coordinates “around”. In some cases, the term “around” refers to the range of radial coordinates within P ( radial ) percentage of the illustrated radial coordinate values, where P ( radial ) is among 10%, 20% and 30%. It can be one. For example, points with z radial coordinates in the range of 7.2 mm and 8.8 mm are in the vicinity of P = 10% of z = 8.0 mm radial coordinate of the "lens, center" reference point. exist.

Moreover, in some embodiments, NA and S are only present in one of three separate ranges listed for the B, C, and D configurations. In some other embodiments, NA and S are in two of three separate ranges listed for the B, C, and D configurations in Tables 11A and 11B.

Visually, the described laser delivery system is fairly calibrated with substantially diffraction limited optical performance over the entire lens surgical volume.

[Table 11a]

Table 11b

Since all of these designs are considered to be diffraction limited systems, similar designs with strel ratios (S) higher than 0.8 can be considered equivalent to the designs listed above.

Other aberration measures, for example focal radius r _f , can also be used in addition to the strel ratio S to characterize the overall optical performance of the laser delivery system 1. Since the large strel ratio in combination with the large numerical apertures NA are transferred to the small focal radii r _f over the configurations A to D, the focal radii r _f is the number of implementations in the eye target area. In the second embodiment, down to 2 microns in another embodiment, and below 10 microns in another embodiment.

To more accurately characterize the performance of the laser delivery system and represent the substantial effects of the lens and cornea on beam propagation, the NA and S values in Tables 11A and 11B are designed by designing a system that includes the eye as an integral part of the optical design. Has been derived. In some designs, the eye is modeled as natural. In other designs, the degree of applanation of the eye is intended to represent the actual surgical condition.

Table 12 summarizes a simple model of related eye tissue, as shown by the model human eye 850 in FIG. 15. (The numbering of the surfaces was chosen to begin with the numbering in Table 10, starting with the surface 18 connecting the patient interface 800 to corneal tissue, surface 18.) The ocular tissue was (through the shared surface 18 the patient It can be modeled by 0.6 mm thick cornea, entering from the interface, intraocular water (entering from the cornea through surface 19) and lens (entering from intraocular water through surface 20). The separation of the eye surface is treated similarly to the separation of the lens surfaces 1 to 16.

[Table 12]

The NA and S values in Tables 11a and 11b were calculated using this model of eye tissue. Relevant models of the eye result in comparable aberration measures.

In a further separation aspect, in some implementations, the optical design of the entire laser delivery system 1 can be simplified by deviating from field curvature and some distortion that is not corrected by the optical means.

16 shows that in some systems this design principle would make the positional accuracy of the surgical system less desirable. As the mirror of the XY scanner 300 scans in 1 degree steps and the Z scanner 450 scans the Z focal depth by moving the beam expander 500 which is movable in 5 degrees steps, the square dots are located at the focal point position. Indicates. Visually, the "focal plane" defined as the XY scanned position of the focal point while maintaining a constant Z focal depth is bent. The cutting depth in the left and right periphery is consistent with the known behavior of lenses with shallower, uncorrected field curvature.

Similarly, when the mirrors of the XY scanner 300 remain fixed and the Z scanner 450 scans the Z focus depth, the left and right positions of the focus change. To further complicate the design, neither the radial left and right XY positions nor the Z focal depth show linear dependence on individual scanner positions. This distortion in the XY plane is called barrel distortion or pincushion distortion. (In many implementations, the third coordinate, the azimuth of the XY scanner 300, is conveyed unchanged to the azimuth of the focal position and will be suppressed accordingly.)

로 주어지고, 여기서

은 Z 스캐너(450)의 위치이고,

은 광학축으로부터 XY 스캐너(300)의 경사각이며,

은 방위각이다. 초점 위치는 실린더 초점 좌표

에 의해 주어지고, z는 Z 초점 깊이이고, r은 광학축으로부터 방사방향 거리이며,

는 방위각이다.FIG. 17 illustrates how some implementations of the laser delivery system 1 provide a novel and computerized solution to the described approach. Scanner coordinates are spatial coordinates

Given by

Is the location of the Z scanner 450,

Is the angle of inclination of the XY scanner 300 from the optical axis,

Is the azimuth. Focus position is cylinder focus coordinate

Is given by, z is the Z focal depth, r is the radial distance from the optical axis,

Is the azimuth.

는

으로서 정의된, 스캐닝 그리드 및 상응하는 스캐너 매트릭스(C_ij)를 정의하는, 개별적인 스캐닝 간격 내에서 구분된다. 실제 스캐너 좌표가 값

을 추정한다면, 이어서 스캐닝 매트릭스(C_ij)는 이런 특정한(i0, j0) 쌍에서 1이고, 모든 다른(i,j) 쌍에 대하여 영이다.The azimuth of the focal position may be substantially the same as the azimuth of the scanner and thus not shown. Remaining XY and Z Scanner Coordinates

The

And defined within a separate scanning interval, defining the scanning grid and corresponding scanner matrix C _ij . The actual scanner coordinate value

, Then the scanning matrix C _ij is 1 in this particular (i0, j0) pair and zero for all other (i, j) pairs.

가 초점 좌표(Z_k, r_l)로 변환하는지를 표시한다: 일반적으로 S = TC 또는 상세하게:Similarly, the focal position can be characterized by a two-dimensional focus matrix S _kl , where S _kl relates to the separated radial and Z depth focal coordinates z _k , r _l . For the scanner matrix C _ij and the focus matrix S _kl , the optical performance of the laser delivery system 1 can be characterized by a four-dimensional transfer matrix T _ijkl , which is generally how the scanner coordinates

Indicates whether to convert to focal coordinates (Z _k , r _l ): usually S = TC or in detail:

While the transfer matrix T _ijkl indicates a linear connection between the scanner matrix C _ij and the focus matrix S _kl , in some other implementations the nonlinear relationship is due to the scanner matrix C _ij and the focus matrix S _kl . May exist between. In this embodiment, equation (5) is replaced by a nonlinear connection.

The laser delivery system 1 can be designed to optimize the elements of the transfer matrix T by computerized ray tracing, physical correction or a combination of both. The implementation of the physical correction method is described in US patent application US20090131921, which can be used for this purpose.

In general, the transfer matrix T can be reversed and used to generate an inverse transfer matrix T ¹ , which connects the elements of the focus matrix S _kl to the scanner matrix C _ij .

Alternatively, in some embodiments the inverse transfer matrix T ¹ can be determined directly by initiating a computerized design process with the desired focus matrix S _kl at the target area, for example using ray tracing. Reconstruct the scanner matrix C _ij .

스캐너 좌표를 도시하는, 노모그램(nomogram)이다.17 and 18 illustrate this relationship. These figures show that the XY scanner 300 or the Z scanner 450 can be fine tuned to focus the beam at the (z _k , r _l ) focal coordinates shown in the z and r axes.

Nomogram, showing scanner coordinates.

경사 각도를 도시한다. 실시예로서, z = 6㎜의 Z 깊이 및 r = 4㎜의 방사방향 위치를 달성하기 위하여, 사선들은

=6.4도의 XY 스캐너 경사 각도가 사용될 수 있다는 것을 나타낸다.17 shows an XY scanner 300 corresponding to (z, r) focal coordinates.

Show the angle of inclination. As an example, in order to achieve a Z depth of z = 6 mm and a radial position of r = 4 mm, the diagonal lines are

Indicates that an XY scanner tilt angle of = 6.4 degrees can be used.

=15.5㎜가 사용될 수 있다는 것을 도시한다. 컴퓨터를 사용하여, 노모그램은 룩-업 테이블(look-up table)과 같이 컴퓨터 메모리에 저장될 수 있다. 저장된 룩-업 좌표들 사이에서 값들은 2차원 선형 또는 이차 보간법에 의해 신속하게 결정될 수 있다.18 shows the Z scanner position, in order to achieve the same (z, r) = (4,6) focal coordinates

It shows that = 15.5 mm can be used. Using a computer, nomograms can be stored in computer memory as a look-up table. The values between the stored look-up coordinates can be quickly determined by two-dimensional linear or quadratic interpolation.

The information of the transfer matrix T and its inverse T ¹ allows the embodiment of the laser delivery system 1 to correct the aberration of FIG. 16 by a computerized method instead of an optical method. Such embodiments may include a computerized controller, which may control at least one of the Z scanner 450 and the XY scanner 300 to control optical distortion of the laser delivery system 1. .

19 illustrates a computerized controller, for example, if scanning along a flat focal plane at a predetermined Z focal depth z is desired in the target area, for example, a scanning pattern with reduced optical distortion. The steps of the control method 900 may be performed.

910: accepting at least one of the incidence z _k , r _l focal coordinates and elements of the focal matrix S _kl corresponding to the scanning pattern with the reduced light irregularities in the target area;

스캐너 좌표들 및 요소들 중 적어도 하나를 저장된 메모리로부터 산출하거나 호출하는 단계; 및920: Using the predetermined inverse transfer matrix T ¹ _ijkl , the scanner matrix C _ij corresponding to the incidence (z _k , r _l ) focal coordinates or elements of the focus matrix S _kl .

Calculating or recalling at least one of the scanner coordinates and elements from a stored memory; And

스캐너 좌표들에 상응하는 XY 스캐너(300) 및 Z 스캐저(450) 중 적어도 하나를 제어하고 초점 매트릭스(S_kl)의 입사(z_k, r_l) 초점 좌표들 또는 요소들에 상응하는 초점을 스캔하는 단계.(930): calculated

It controls at least one of the XY scanner 300 and the Z scanner 450 corresponding to the scanner coordinates and focuses corresponding to the incident (z _k , r _l ) focal coordinates or elements of the focus matrix S _kl . Scanning step.

Laser delivery systems with such computerized controllers can reduce light distortion for the same or similar laser systems without such controllers. The degree of reduction may be as much as 10% in some embodiments, and as much as 30% in other embodiments.

The reduced optical distortion can be any one of aberration, field curvature, barrel distortion, pincushion distortion, curved focal plane, and bent scanning line, intended to be parallel to the Z axis.

In some implementations, the computerized controller may include precompilator 200, XY scanner 300, Z scanner 450, and objective 700, perhaps using any of the features described above. This, together with the other blocks of the laser delivery system, performs these functions.

The number of possible and similar implementations is quite large, depending on the principle of computerized control to reduce optical aberrations. For example, in some embodiments the computerized controller can scan the focus across a focal plane having curvature below the threshold curvature value. In some other implementations a surface having a predetermined shape can be scanned with the proper operation of the computerized controller.

While this document contains many details, it should be constructed as a description of particular features of particular embodiments of the invention rather than being a limitation on the scope of the invention or of what may be claimed. Certain features that are described in this document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in any cooperative or separate multiple embodiments. Moreover, although the features act in particular combinations and are even described above as initially claimed as such, one or more features from the claimed combination may in some cases be deleted from the combination, and the claimed combination may be modified in a subcombination. Or in an auxiliary combination.

Implementations of many imaging guided laser surgical techniques, devices, and systems are disclosed. However, variations and enhancements of the described implementations, and other implementations, may be constructed on the basis of what has been described.

Claims (19)

In the laser system for ophthalmic surgery,
A laser source for generating a pulsed laser beam;
An XY scanner for scanning a pulsed laser beam in an XY direction transverse to the Z axis;
A Z scanner for scanning an XY scanned laser beam along the Z axis; And
Includes an objective that focuses the XYZ scanned laser beam into the target area,
Focused scanned laser beams are subject to a certain azimuth angle within the target area.

Also have a numerical aperture (NA) and a strel ratio (S) at radial coordinates (z, r), all in millimeters;
in the vicinity of (z, r) = (0.3, 0.0), NA is between 0.25 and 0.40 and S is between 0.8 and 1.0;
A laser system, characterized in that NA and S are present in at least one of each of the following target areas.
in the vicinity of (z, r) = (0.3, 6.2), the target region where NA is between 0.25 and 0.40 and S is between 0.8 and 1.0;
in the vicinity of (z, r) = (8.0, 0.0), the target region where NA is between 0.15 and 0.35 and S is between 0.8 and 1.0; And
target region in the vicinity of (z, r) = (7.4, 4.0), where NA is between 0.15 and 0.35 and S is between 0.8 and 1.0.
The method of claim 1,
Wherein the NA and S are in two of the three respective target regions.
The method of claim 1,
Wherein the NA and S are in all three respective target regions.
The method of claim 1,
The vicinity of the radial coordinates (z, r) includes points, wherein the radial coordinates of the points do not deviate from the radial coordinates (z, r) to exceed P ( radial ) percentages,
P ( radial ) is a laser system, characterized in that one of 10%, 20% and 30%.
The method of claim 1,
in the vicinity of (z, r) = (0.3, 0.0), NA is between 0.30 and 0.35 and S is between 0.8 and 1.0;
A laser system, characterized in that NA and S are present in at least one of each of the following target areas.
in the vicinity of (z, r) = (0.3, 6.2), the target region where NA is between 0.30 and 0.35 and S is between 0.8 and 1.0;
in the vicinity of (z, r) = (8.0, 0.0), the target region where NA is between 0.20 and 0.25 and S is between 0.8 and 1.0; And
target region in the vicinity of (z, r) = (7.4, 4.0), where NA is between 0.20 and 0.25 and S is between 0.8 and 1.0.
The method of claim 5, wherein
Wherein the NA and S are in two of the three respective target regions.
The method of claim 5, wherein
Wherein the NA and S are in all three respective target regions.
The method of claim 5, wherein
The vicinity of the radial coordinates (z, r) includes points, wherein the radial coordinates of the points do not deviate from the radial coordinates (z, r) to exceed P ( radial ) percentages,
P ( radial ) is a laser system, characterized in that one of 10%, 20% and 30%.
The method of claim 1,
Wherein the NA and S values relate to a laser system optically coupled to one of the human eye and one of the models of the eye via the patient interface.
The method of claim 9, wherein the eye model,
Including a first surface, a second surface, and a third surface,
The corneal region is defined to have a thickness of about 0.6 mm and a refractive index of about 1.38,
The antechamber region is defined as having a thickness in the range of 2 mm to 4 mm and a refractive index of about 1.34,
The lens region is defined to have a thickness in the range of 3 mm to 5 mm and a refractive index of about 1.42,
All three surfaces have a curvature in the range of −100 m ⁻¹ to −80 m ⁻¹ .
The method of claim 1, wherein the laser system,
And a precompensator, positioned between the laser source and the XY scanner.
The method of claim 11,
The precompensator has a movable lens and Z scans the laser beam.
The method of claim 1,
And the Z scanner is configured to substantially adjust the Z focal depth and the numerical aperture (NA) independently.
The method of claim 1, wherein the Z scanner,
A first lens group; And
A laser system comprising a movable beam scanner.
The method of claim 1,
And the Z scanner positioned separately from the objective in front of the objective.
In the laser system for ophthalmic surgery,
A laser source for generating a pulsed laser beam;
An XY scanner for scanning the pulsed laser beam in the XY direction transverse to the Z axis;
A Z scanner for scanning an XY scanned laser beam along the Z axis; And
Includes an objective that focuses the XYZ scanned laser beam into the target area,
The focused scanned laser beam has a focus with a focal radius,
The focal radius is less than r _f ( max ) in the target area,
And the target area extends about 8 millimeters along the Z axis and about 10 millimeters in the XY direction.
17. The method of claim 16,
r _f ( max ) is 2 micrometers.
17. The method of claim 16,
r _f ( max ) is a 4 micrometer laser system.
17. The method of claim 16,
r _f ( max ) is related to a laser system coupled to one of the human eye and a model of the human eye.

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