KR20120068819A - Optical system for ophthalmic surgical laser - Google Patents
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- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F9/00825—Methods or devices for eye surgery using laser for photodisruption
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- A—HUMAN NECESSITIES
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- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F9/00825—Methods or devices for eye surgery using laser for photodisruption
- A61F9/0084—Laser features or special beam parameters therefor
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
- G02B27/0031—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration for scanning purposes
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
- G02B27/0068—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration having means for controlling the degree of correction, e.g. using phase modulators, movable elements
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0075—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for altering, e.g. increasing, the depth of field or depth of focus
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F2009/00844—Feedback systems
- A61F2009/00848—Feedback systems based on wavefront
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F2009/00855—Calibration of the laser system
- A61F2009/00859—Calibration of the laser system considering nomograms
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F2009/00861—Methods or devices for eye surgery using laser adapted for treatment at a particular location
- A61F2009/0087—Lens
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F2009/00861—Methods or devices for eye surgery using laser adapted for treatment at a particular location
- A61F2009/00872—Cornea
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F2009/00897—Scanning mechanisms or algorithms
Abstract
The laser system for ophthalmic surgery includes a laser engine for generating a pulsed laser beam, and an XY scanner for receiving the generated pulsed laser beam and emitting a scanning laser beam, wherein the XY scanner comprises two X scanning mirrors; And a Y scanner comprising two Y scanning mirrors. The XY scanner can independently change the angle that the emitted scanning laser beam makes with respect to the optical axis, and the position at which the emitted scanning laser beam intersects with a continuous reference plane perpendicular to the optical axis.
Description
This application claims the benefit and claims from this patent application “Optical Systems for Ophthalmic Surgical Lasers,” Serial No. 12 / 511,979, filed July 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.
Laser systems for ophthalmic surgery, briefly and generally, include a laser engine that generates a pulsed laser beam, and an XY scanner that receives the generated pulsed laser beam and emits a scanning laser beam, wherein the XY scanner includes two X scanning mirrors. An X scanner, and a Y scanner including two Y scanning mirrors.
In some implementations, the X scanner is configured such that the pivot point of the X scanner is away from the mirror of the X scanner.
In some implementations, the pivot point of the X scanner is substantially on the mirror of the Y scanner.
In some implementations the Y scanner is configured such that the pivot point of the Y scanner is away from the mirror of the Y scanner.
In some implementations, the X scanner and the Y scanner are configured such that the pivot point of the X scanner is away from the mirror of the X scanner, the pivot point of the Y scanner is away from the mirror of the Y scanner, and the X scanner pivot point is substantially coincident with the Y scanner pivot point. .
In some implementations the X scanner and Y scanner are configured such that the X scanner pivot point substantially coincides with the Y scanner pivot point.
In some implementations the pivot point of the Y scanner is on the incident surface of the substantially continuous optical element.
In some implementations the pivot point of the Y scanner is on the incident pupil of the substantially continuous optical element.
In some implementations the XY scanner is configured to substantially change the position at which the scanning laser beam emitted by the XY scanner intersects the angle with respect to the optical axis and the position at which the emitted scanning laser beam intersects with a continuous reference plane perpendicular to the optical axis. .
In some implementations the XY scanner is configured to reduce the aberration as compared to the aberration of a corresponding laser system including an XY scanner having only two mirrors.
In some implementations the XY scanner is configured to reduce astigmatism compared to astigmatism of a corresponding laser system that includes an XY scanner having only two mirrors.
In some implementations the XY scanner is configured to reduce coma compared to the coma of a substantially identical laser system that includes an XY scanner having only two mirrors.
In some implementations, the XY scanner is configured to scan the laser beam over an XY scanning range whose maximum in the focal plane of the laser system is longer than 5 millimeters and shorter than 15 millimeters.
In some implementations, the XY scanner is configured to scan the laser beam over an XY scanning range whose maximum in the focal plane of the laser system is longer than 8 millimeters and shorter than 13 millimeters.
In some implementations, a laser system for ophthalmic surgery includes a laser engine for generating a pulsed laser beam, and an XY scanner that receives the generated pulsed laser beam and emits a scanning laser beam, wherein the XY scanner includes a substantially exiting scanning laser beam. Configured to independently change the angle made with respect to the optical axis and the position at which the emitted scanning laser beam intersects a continuous reference plane perpendicular to the optical axis.
In some embodiments the XY scanner comprises an X scanner comprising two X scanning mirrors, and a Y scanner comprising two Y scanning mirrors.
In some implementations the X pivot point is away from the X scanning mirror and the Y pivot point is away from the Y scanning mirror.
In some implementations, the X pivot point is away from the X scanning mirror, the Y pivot point is away from the Y scanning mirror, and the X pivot point is substantially coincident with the Y pivot point.
In some implementations, the XY scanner is configured to scan the laser beam over an XY scanning range whose maximum in the focal plane of the laser system is longer than 5 millimeters and shorter than 15 millimeters.
In some implementations a laser system for ophthalmic surgery includes a laser engine for generating a pulsed laser beam, and an XY scanner that receives the pulsed laser beam and emits a scanning laser beam, wherein the XY scanner comprises a first fast steering XY scanning mirror, and Two fast steering XY scanning mirrors, wherein the first and second fast steering XY mirrors enable angular motion about two axes of rotation.
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 are substantially coincident.
1 shows a surgical
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
7A and 7B illustrate various uses of an efficient Z scanning function.
8A-8D illustrate the implementation of the
9 shows an implementation of a
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 shows the steps of the control method using a computer.
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.
1 shows a
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
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
The
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
In FIG. 1, the beam associated with the visible observation optics and imaging system may be coupled to the
1 includes a
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 limits, eg, laser parameters falling within the 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
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)
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,
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
3A shows the case when the
3B shows the case when the
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
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
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
In order to address the problem of large aberration measures associated with lens surgery, some embodiments include
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
Thus, in some implementations, the presentation introduced by the
Since the spherical aberration predominantly affects the axial rays, the
Thus, in designs where the precompilator is located behind the
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
Some implementations even utilize the interdependence of on-axis and off-axis aberrations mentioned above by introducing on-axis presentation by the
6A and 6B schematically illustrate the idealized operation of the
6a shows a
6B shows that
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
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
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"
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
In some implementations, the addition of the precompilator 220 to the unshown
Additional free Com pense
In some implementations the addition of the
In some implementations the addition of the
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
In some implementations, installing the
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,
In some implementations, the
In some implementations, the
Some of these functions can be reached by including one or more movable lenses into the
In an implementation with one movable lens, the movable lens of the
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
In some general existing systems, aberrations are dominantly compensated by optical means, for example lenses. The presently described
7A shows that such an improvement may be useful when the traversing
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
In some implementations, the
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
Some of the functions of the
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
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
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
Table 2 also shows three fixed lens embodiments of the
TABLE 2 for FIG. 8A
Table 3 shows two movable lenses 222 ′, 223 ′, showing lens spacings diA, diB in two configurations A, B in
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
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
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
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
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
In addition, some implementations have two NA controllers: one NA controller in front of the
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
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.
The
In some embodiments the
11A shows that
These two
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
FIG. 11B shows an existing three
Since the X
However, even this design has a similar problem to that of FIG. 11A only considering the
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
11C shows four mirror designs that address this problem. In
Another aspect of this design is substantially independent of (i) the angle (α) between the optical axis of the
Some implementations of the XY scanner 300 '' 'include only one
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
1 shows that some implementations of the
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
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
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
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
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
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
Z scanner in front of
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
As described above, the numerical aperture NA can be adjusted extensively with or without the
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
As described below, a laser delivery system that generates a pivot point PP (O) positioned out of the mirrors of the
In another embodiment, the
In either case, this implementation allows the use of the presence of the intermediate
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 /
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
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
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 drop to any of the four mass ranges above: 0 to 400 grams, 400 to 750 grams, 750 to 1,350 grams and 1,350 to 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
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. (
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 entrance 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 also has a refractive index in the range of 1.56 to 1.85, a second lens separated from the first lens by a distance in the range of 0 to 6.5 mm, curvature in the range of -55.1 to -21.8 1 / m And an exit surface having a curvature in the range of 11.4 to 26.8 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
Numerous other implementations of the overall
6. Overall system optical performance
In various implementations, the parameters of the subsystems, the
Tables 11a and 11b summarize the optical performance of the overall
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 fall only in one of three separate ranges listed for the B, C, and D configurations. In some other embodiments, NA and S fall into two of the 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
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
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
Similarly, when the mirrors of the
FIG. 17 illustrates how some embodiments of the
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
Is 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.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
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
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 starting 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 .
17 and 18 illustrate this relationship. These figures show that the
17 shows an
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
19 shows a scanning pattern with a reduced optical distortion, for example, if scanning along a flat focal plane at a predetermined Z focal depth z is desired in the target area, a controller using a computer may be used. The steps of the
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 optical distortion in the target area;
920: 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 the stored memory; And(930): calculated
Controlling at least one of theLaser delivery systems with such computerized controllers can reduce optical 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 휜 scanning line, intended to be parallel to the Z axis.
In some implementations, a computerized controller may include a
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 a computerized controller can scan the focus over a focal plane having a curvature below a threshold curvature value. In some other implementations a surface having a predetermined shape can be scanned with the proper operation of a computer-based 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 (21)
A laser engine for generating a pulsed laser beam; And
An XY scanner that receives the generated pulsed laser beam and emits a scanning laser beam,
The XY scanner includes an X scanner comprising two X scanning mirrors, and a Y scanner comprising two Y scanning mirrors.
And the X scanner is configured such that the pivot point of the X scanner is away from the mirror of the X scanner.
Wherein the pivot point of the X scanner is substantially on the mirror of the Y scanner.
Y scanner is a laser system, characterized in that the pivot point of the Y scanner is configured to exist away from the mirror of the Y scanner.
X scanner and Y scanner are configured such that the pivot point of the X scanner is away from the mirror of the X scanner, the pivot point of the Y scanner is away from the mirror of the Y scanner, and the X scanner pivot point is substantially coincident with the Y scanner pivot point. Laser system.
And the X scanner and the Y scanner are configured such that the X scanner pivot point substantially coincides with the Y scanner pivot point.
The pivot point of the Y scanner is on the incident surface of the substantially continuous optical element.
The pivot point of the Y scanner is on the incident pupil of the substantially continuous optical element.
The XY scanner is configured to independently change the position at which the scanning laser beam emitted by the XY scanner intersects the angle with respect to the optical axis and the position at which the emitted scanning laser beam intersects with a continuous reference plane perpendicular to the optical axis. Laser system.
And the XY scanner is configured to reduce the aberration relative to the aberration of a corresponding laser system comprising an XY scanner having only two mirrors.
And the XY scanner is configured to reduce astigmatism relative to astigmatism of a corresponding laser system comprising an XY scanner having only two mirrors.
And the XY scanner is configured to reduce the coma as compared to the coma of a substantially identical laser system comprising an XY scanner having only two mirrors.
And the XY scanner is configured to scan the laser beam over an XY scanning range whose maximum in the focal plane of the laser system is longer than 5 millimeters and shorter than 15 millimeters.
And the XY scanner is configured to scan the laser beam over an XY scanning range whose maximum in the focal plane of the laser system is longer than 8 millimeters and shorter than 13 millimeters.
A laser engine for generating a pulsed laser beam; And
An XY scanner that receives the generated pulsed laser beam and emits a scanning laser beam,
And the XY scanner is configured to independently change the angle that the substantially emitted scanning laser beam makes with respect to the optical axis, and the position at which the emitted scanning laser beam intersects with a continuous reference plane perpendicular to the optical axis.
The XY scanner includes an X scanner comprising two X scanning mirrors, and a Y scanner comprising two Y scanning mirrors.
The X pivot point is away from the X scanning mirror,
The Y pivot point is located away from the Y scanning mirror.
The X pivot point is away from the X scanning mirror,
The Y pivot point lies away from the Y scanning mirror,
Wherein the X pivot point substantially coincides with the Y pivot point.
And the XY scanner is configured to scan the laser beam over an XY scanning range whose maximum in the focal plane of the laser system is longer than 5 millimeters and shorter than 15 millimeters.
A laser engine for generating a pulsed laser beam; And
An XY scanner that receives a pulsed laser beam and emits a scanning laser beam,
The XY scanner includes a first fast steering XY scanning mirror and a second fast steering XY scanning mirror, wherein the first and second fast steering XY mirrors enable angular motion about two axes of rotation. system.
And 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 substantially coincide.
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- 2010-07-21 KR KR1020127002653A patent/KR20120068819A/en not_active Application Discontinuation
- 2010-07-21 JP JP2012522900A patent/JP5540097B2/en active Active
- 2010-07-21 CN CN201080043148.3A patent/CN102596126B/en not_active Expired - Fee Related
- 2010-07-21 EP EP10806836A patent/EP2459135A4/en not_active Withdrawn
Also Published As
Publication number | Publication date |
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RU2544371C2 (en) | 2015-03-20 |
AU2010281494B2 (en) | 2015-01-22 |
EP2459135A2 (en) | 2012-06-06 |
MX2012001330A (en) | 2012-08-15 |
RU2012107317A (en) | 2013-09-10 |
CN102596126B (en) | 2014-08-13 |
JP5540097B2 (en) | 2014-07-02 |
JP2013500131A (en) | 2013-01-07 |
EP2459135A4 (en) | 2012-11-07 |
AU2010281494A1 (en) | 2012-02-16 |
CA2769099A1 (en) | 2011-02-10 |
CN102596126A (en) | 2012-07-18 |
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