Patent Description:
Vitreous floaters are small particles consisting of cells, pigment, or fibrin that move in the vitreous of the eye. Patients with opaque vitreous humor floaters can suffer from blind spots and deteriorated vision. Vitreous surgery can improve visual acuity in these patients.

Traditionally, vitreous surgery (vitrectomy) was performed by cutting the eye to remove the floaters with mechanical surgical tools, such as a vitreous infusion suction cutter that cut the vitreous and removed the debris from the eye by suction. Other vitrectomy methods have included using an argon laser to alter the trabecular meshwork to increase outflow of the aqueous, and using a nanosecond pulsed laser to tediously steer the laser visually to treat the floaters, thereby subjecting the retina to shock waves, mechanical distortions, as well as direct laser exposure of energy levels needed to treat the floaters effectively. <CIT> describes a device and a method for the femtosecond laser surgery of tissue, especially in the vitreous humor of the eye. The device consists of an ultrashort pulse laser with pulse widths in the range of approximately 10fs-1ps, especially approximately 300fs, pulse energies in the range of approximately 5nJ-5pJ, especially approximately <NUM>-<NUM>µJ and pulse repetition rates of approximately <NUM>-<NUM>, especially <NUM>. The laser system is coupled to a scanner system which allows the spatial variation of the focus in three dimensions (x, y and z). In addition to said therapeutic laser/scanner optical system the device furthermore consists of a navigation system coupled thereto. An object of the methods and devices disclosed by the document is to induce or promote liquefaction of the vitreous body. This is done by cuts or perforations with the ultra-short pulsed laser radiation that cuts through vitreous cords and thus increases metabolic exchange. Examples of cutting geometries according to the document are shown in figures of the document, and correspond to planar sections oriented essentially perpendicular to the optical axis of the eye, or to a structure resembling onion skins. <CIT> describes systems and methods for performing ophthalmic surgical procedures using laser device, and more particularly for treating target tissue in the vitreous cavity of an eye. In embodiments, the document provides a system and method for using an OCT guided femtosecond laser to treat target tissue in the vitreous cavity of an eye. In embodiments, the target tissue may be or include floaters in the vitreous cavity.

In view of these challenges, improved methods and systems for treating vitreous floaters are needed.

Accordingly, improved laser eye surgery systems are provided to substantially obviate one or more problems due to limitations and disadvantages of the related art. In many embodiments, the laser eye surgery systems use a laser to treat vitreous bodies, or floaters, using a pulsed laser treatment beam, a ranging subsystem to measure the spatial disposition of external and internal structures of the eye, an alignment subsystem, and shared optics operable to scan the treatment beam, a ranging subsystem beam, and/or an alignment beam relative to the laser eye surgery system. The alignment subsystem can include a video subsystem that can be used to, for example, provide images of the eye during docking of the eye to the laser eye surgery system. In certain embodiments, a liquid interface may be used between a patient interface lens and the eye. The use of the liquid interface avoids imparting undesirable forces to the patient's eye and provides a clear optical path for the laser and imaging systems. The alignment and ranging subsystems may be used to detect structures involved with the patient interface. In certain embodiments, a contact lens is used on the patient during treatment.

Thus, in one aspect, a laser eye surgery system is provided. The laser eye surgery system includes a laser source, a ranging subsystem, an integrated optical subsystem, and a patient interface assembly. The laser source is configured to produce a treatment beam that includes a plurality of laser pulses. In some embodiments, the ranging subsystem is configured to produce a source beam used to locate one or more structures of an eye. The ranging subsystem may include an optical coherence tomography (OCT) pickoff assembly that includes a first optical wedge and a second optical wedge separated from the first optical wedge. The OCT pickoff assembly is configured to divide the source beam into a sample beam and a reference beam. The integrated optical subsystem is configured to receive the treatment beam, direct the treatment beam to selected treatment locations within the eye so as to incise tissue at the selected treatment locations, receive the sample beam, direct the sample beam to selected measurement locations within the eye, and transmit return portions of the sample beam from the selected measurement locations back to the ranging subsystem for processing by the ranging subsystem. The patient interface assembly is configured to couple the eye with the integrated optical subsystem so as to constrain the eye relative to the integrated optical subsystem and provide coupling of treatment and ranging light to and within the eye.

Variations of the laser eye surgery system are provided. For example, the patient interface assembly can include a patient interface lens having a posterior surface spaced from the eye when the patient interface assembly couples the eye with the integrated optical subsystem. The patient interface assembly can be configured to accommodate a volume of fluid interfaced with both the patient interface lens posterior surface and the eye. The patient interface assembly can be configured to demountably couple with the integrated optical subsystem to enable replacement of the patient interface assembly between treatments. The patient interface assembly can be, for example, a removable assembly, an interchangeable assembly, and/or an exchangeable assembly. The patient interface lens can have an anterior surface disposed between the patient interface lens posterior surface and the integrated optical subsystem. The ranging subsystem can be used to locate the patient interface lens anterior surface and the patient interface lens posterior surface relative to the ranging subsystem and the integrated optical subsystem. The integrated optical subsystem can be controlled in part based on the locations of the patient interface lens anterior and posterior surfaces so as to at least one of said direct the treatment beam to selected treatment locations within the eye to incise tissue at the selected treatment locations or said direct the sample beam to selected measurement locations within the eye. The OCT ranging subsystem is split into a reference and sample beam. This splitting may be achieved using two optical wedges. Each of the first and second optical wedges can have non-parallel anterior and posterior surfaces. The source beam can propagate through the first optical wedge and into the second optical wedge. The second optical wedge posterior surface can be partially reflective so as to divide the source beam into the sample beam and the reference beam. The sample beam can propagate out of the second optical wedge through the posterior surface. The reflected reference beam can propagate out of the second optical wedge through the anterior surface and propagate back through the first optical wedge and along a reference optical path. A returning portion of the sample beam can be at least one of retro-reflected or scattered and returned back through the second optical wedge. The sample beam returning portion can propagate back through the first optical wedge. The reference beam, after traversing a path length, can be retro-reflected and can propagate back into the second optical wedge through the anterior surface. A reflected portion of the reference beam can then be reflected by the second optical wedge posterior surface. The reference beam reflected portion can propagate out of the second optical wedge through the anterior surface and propagate through the first optical wedge. The first and second optical wedges can have the same wedge angle and be arranged such that the wedge angles are opposing. The wedge angle of the first and second optical wedges can be in a range from <NUM> degrees to <NUM> degrees. The wedge angle of the first and second optical wedges can be in a range from <NUM> degrees to <NUM> degrees. The first and second optical wedges can be made from the same material having a refractive index of greater than <NUM> with respect to the wavelength of the source beam. The refractive index can be greater than <NUM> with respect to the wavelength of the source beam. The first optical wedge anterior and posterior surfaces can have an anti-reflection coating. The second optical wedge anterior surface can have the anti-reflection coating. The second optical wedge posterior surface can be uncoated. The anti-reflection coating can be magnesium fluoride (MgF<NUM>). The source beam can have an angle of incidence on the second optical wedge posterior surface of less than <NUM> degrees. The angle of incidence can be less than <NUM> degrees. The OCT pickoff assembly comprised of the two wedges, for example, can be configured to have low angles of incidence at all surfaces such that the OCT pickoff assembly is substantially polarization insensitive. The first and second optical wedges can be separated by a distance greater than a detection range of the ranging subsystem to inhibit etalon effects. The second optical wedge anterior surface and the first optical wedge posterior surface can be non-parallel to inhibit etalon effects. The second optical wedge anterior surface and the first optical wedge posterior surface can deviate from parallel by <NUM> degrees to <NUM> degrees to inhibit etalon effects. The second optical wedge anterior surface and the first optical wedge posterior surface can deviate from parallel by <NUM> degrees to <NUM> degrees to inhibit etalon effects.

This summary and the following detailed description are merely exemplary, illustrative, and explanatory, and are not intended to limit, but to provide further explanation of the invention as claimed. Additional features and advantages of the invention will be set forth in the descriptions that follow, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description, claims and the appended drawings.

The drawings and related descriptions of the embodiments have been simplified to illustrate elements that are relevant for a clear understanding of these embodiments, while eliminating various other elements found in conventional laser eye surgery systems. Those of ordinary skill in the art may thus recognize that other elements and/or steps are desirable and/or required in implementing the embodiments that are claimed and described. But, because those other elements and steps are well-known in the art, and because they do not necessarily facilitate a better understanding of the embodiments, they are not discussed. This disclosure is directed to all applicable variations, modifications, changes, and implementations known to those skilled in the art. As such, the following detailed descriptions are merely illustrative and exemplary in nature and are not intended to limit the embodiments of the subject matter or the uses of such embodiments. As used in this application, the terms "exemplary" and "illustrative" mean "serving as an example, instance, or illustration. " Any implementation described as exemplary or illustrative is not meant to be construed as preferred or advantageous over other implementations. Further, there is no intention to be bound by any expressed or implied theory presented in the preceding background, brief summary, or the following detailed description.

Embodiments proving systems for laser eye surgery are disclosed. A laser beam is used to form precise incisions in the cornea, in the lens capsule, and/or in the crystalline lens nucleus. In many embodiments, a laser eye surgery system includes a cutting laser subsystem to produce a pulsed laser treatment beam to incise tissue within the eye, a ranging subsystem to measure the spatial disposition of external and internal structures of the eye in which incisions can be formed, an alignment subsystem, and shared optics operable to scan the treatment beam, a ranging subsystem beam, and/or an alignment beam relative to the laser eye surgery system. The alignment subsystem can include a video subsystem that can be used to, for example, provide images of the eye during docking of the eye to the laser eye surgery system and also provide images of the eye once the docking process is complete. In many embodiments, a liquid interface is used between a patient interface lens and the eye. The use of the liquid interface avoids imparting undesirable forces to the patient's eye.

<FIG> shows a laser eye surgery system <NUM>, according to many embodiments, operable to form precise incisions in the vitreous humor, anterior chamber of the eye as well as other structures in the eye such as cornea, lens capsule, and crystalline lens nucleus. The system <NUM> includes a main unit <NUM>, a patient chair <NUM>, a dual function footswitch <NUM>, and a laser footswitch <NUM>.

The main unit <NUM> includes many primary subsystems of the system <NUM>. For example, externally visible subsystems include a touch-screen control panel <NUM>, a patient interface assembly <NUM>, patient interface vacuum connections <NUM>, a docking control keypad <NUM>, a patient interface radio frequency identification (RFID) reader <NUM>, external connections <NUM> (e.g., network, video output, footswitch, USB port, door interlock, and AC power), laser emission indicator <NUM>, emergency laser stop button <NUM>, key switch <NUM>, and USB data ports <NUM>.

In some embodiments, the patient chair <NUM> includes a base <NUM>, a patient support bed <NUM>, a headrest <NUM>, a positioning mechanism, and a patient chair joystick control <NUM> disposed on the headrest <NUM>. The positioning control mechanism is coupled between the base <NUM> and the patient support bed <NUM> and headrest <NUM>. The patient chair <NUM> is configured to be adjusted and oriented in three axes (x, y, and z) using the patient chair joystick control <NUM>. The headrest <NUM> and a restrain system (not shown, e.g., a restraint strap engaging the patient's forehead) stabilize the patient's head during the procedure. The headrest <NUM> includes an adjustable neck support to provide patient comfort and to reduce patient head movement. The headrest <NUM> is configured to be vertically adjustable to enable adjustment of the patient head position to provide patient comfort and to accommodate variation in patient head size.

The patient chair <NUM> allows for tilt articulation of the patient's legs, torso, and head using manual adjustments. The patient chair <NUM> accommodates a patient load position, a suction ring capture position, and a patient treat position. In the patient load position, the chair <NUM> is rotated out from under the main unit <NUM> with the patient chair back in an upright position and patient footrest in a lowered position. In the suction ring capture position, the chair is rotated out from under the main unit <NUM> with the patient chair back in reclined position and patient footrest in raised position. In the patient treat position, the chair is rotated under the main unit <NUM> with the patient chair back in reclined position and patient footrest in raised position.

The patient chair <NUM> may be equipped with a "chair enable" feature to protect against unintended chair motion. The patient chair joystick <NUM> can be enabled in either of two ways. First, the patient chair joystick <NUM> incorporates a "chair enable" button located on the top of the joystick. Control of the position of the patient chair <NUM> via the joystick <NUM> can be enabled by continuously pressing the "chair enable" button. Alternately, the left foot switch <NUM> of the dual function footswitch <NUM> can be continuously depressed to enable positional control of the patient chair <NUM> via the joystick <NUM>.

In many embodiments, the patient control joystick <NUM> is a proportional controller. For example, moving the joystick a small amount can be used to cause the chair to move slowly. Moving the joystick a large amount can be used to cause the chair to move faster. Holding the joystick at its maximum travel limit can be used to cause the chair to move at the maximum chair speed. The available chair speed can be reduced as the patient approaches the patient interface assembly <NUM>.

The emergency stop button <NUM> can be pushed to stop emission of all laser output, release vacuum that couples the patient to the system <NUM>, and disable the patient chair <NUM>. The stop button <NUM> may be located on the system front panel, next to the key switch <NUM>.

The key switch <NUM> can be used to enable the system <NUM>. When in a standby position, the key can be removed and the system is disabled. When in a ready position, the key may enable power to the system <NUM>.

The dual function footswitch <NUM> may be a dual footswitch assembly that includes the left foot switch <NUM> and a right foot switch <NUM>. The left foot switch <NUM> is the "chair enable" footswitch. The right footswitch <NUM> is a "vacuum ON" footswitch that enables vacuum to secure a liquid optics interface suction ring to the patient's eye. The laser footswitch <NUM> is a shrouded footswitch that activates the treatment laser when depressed while the system is enabled.

In certain embodiments, the system <NUM> includes external communication connections. For example, the system <NUM> can include a network connection (e.g., an RJ45 network connection) for connecting the system <NUM> to a network. The network connection can be used to enable network printing of treatment reports, remote access to view system performance logs, and remote access to perform system diagnostics. The system <NUM> can include a video output port (e.g., HDMI) that can be used to output video of treatments performed by the system <NUM>. The output video can be displayed on an external monitor for, for example, viewing by family members and/or training. The output video can also be recorded for, for example, archival purposes. The system <NUM> can include one or more data output ports (e.g., USB) to, for example, enable export of treatment reports to a data storage device. The treatments reports stored on the data storage device can then be accessed at a later time for any suitable purpose such as, for example, printing from an external computer in the case where the user without access to network based printing.

<FIG> shows a simplified block diagram of the system <NUM> coupled with a patient eye <NUM>. The patient eye <NUM> comprises a cornea, a lens, an iris and an anterior chamber. The iris defines a pupil of the eye <NUM> that may be used for alignment of eye <NUM> with system <NUM>. The system <NUM> includes a cutting laser subsystem <NUM>, a ranging subsystem <NUM>, an alignment guidance system <NUM>, shared optics <NUM>, a patient interface <NUM>, control electronics <NUM>, a control panel/GUI <NUM>, user interface devices <NUM>, and communication paths <NUM>. The control electronics <NUM> may be operatively coupled via the communication paths <NUM> with the cutting laser subsystem <NUM>, the ranging subsystem <NUM>, the alignment guidance subsystem <NUM>, the shared optics <NUM>, the patient interface <NUM>, the control panel/GUI <NUM>, and the user interface devices <NUM>.

In many embodiments, the cutting laser subsystem <NUM> incorporates femtosecond (FS) laser technology. By using femtosecond laser technology, a short duration (e.g., approximately <NUM>-<NUM> seconds in duration) laser pulse (with energy level in the micro joule range) can be delivered to a tightly focused point to disrupt tissue, thereby substantially lowering the energy level required as compared to the level required for ultrasound fragmentation of the lens nucleus and as compared to laser pulses having longer durations.

The cutting laser subsystem <NUM> can produce laser pulses having a wavelength suitable to the configuration of the system <NUM>. As a non-limiting example, the system <NUM> can be configured to use a cutting laser subsystem <NUM> that produces laser pulses having a wavelength from <NUM> to <NUM>. For example, the cutting laser subsystem <NUM> can have a diode-pumped solid-state configuration with a <NUM> (+/- <NUM>) nm center wavelength.

The cutting laser subsystem <NUM> can include control and conditioning components. For example, such control components can include components such as a beam attenuator to control the energy of the laser pulse and the average power of the pulse train, a fixed aperture to control the cross-sectional spatial extent of the beam containing the laser pulses, one or more power monitors to monitor the flux and repetition rate of the beam train and therefore the energy of the laser pulses, and a shutter to allow/block transmission of the laser pulses. Such conditioning components can include an adjustable zoom assembly to adapt the beam containing the laser pulses to the characteristics of the system <NUM> and a fixed optical relay to transfer the laser pulses over a distance while accommodating laser pulse beam positional and/or directional variability, thereby providing increased tolerance for component variation.

The ranging subsystem <NUM> may be configured to measure the spatial disposition of eye structures in three dimensions. The measured eye structures can include the anterior chamber, any vitreous bodies within the anterior chamber, the retina, as well as other structures such as the anterior and posterior surfaces of the cornea, the anterior and posterior portions of the lens capsule, the iris, and the limbus. In many embodiments, the ranging subsystem <NUM> utilizes optical coherence tomography (OCT) imaging. As a non-limiting example, the system <NUM> can be configured to use an OCT imaging system employing wavelengths from <NUM> to <NUM>. For example, the ranging subsystem <NUM> can include an OCT imaging system that employs a broad spectrum of wavelengths from <NUM> to <NUM>. Such an OCT imaging system can employ a reference path length that is adjustable to adjust the effective depth in the eye of the OCT measurement, thereby allowing the measurement of system components including features of the patient interface that lie anterior to the cornea of the eye and structures of the eye that range in depth from the anterior surface of the cornea to the posterior portion of the lens capsule and beyond.

The alignment guidance subsystem <NUM> can include a laser diode or gas laser that produces a laser beam used to align optical components of the system <NUM>. The alignment guidance subsystem <NUM> can include LEDs or lasers that produce a fixation light to assist in aligning and stabilizing the patient's eye during docking and treatment. The alignment guidance subsystem <NUM> can include a laser or LED light source and a detector to monitor the alignment and stability of the actuators used to position the beam in X, Y, and Z. The alignment guidance subsystem <NUM> can include a video system that can be used to provide imaging of the patient's eye to facilitate docking of the patient's eye <NUM> to the patient interface <NUM>. The imaging system provided by the video system can also be used to direct via the GUI the location of cuts. The imaging provided by the video system can additionally be used during the laser eye surgery procedure to monitor the progress of the procedure, to track movements of the patient's eye <NUM> during the procedure, and to measure the location and size of structures of the eye such as the pupil and/or limbus.

The shared optics <NUM> provides a common propagation path that is disposed between the patient interface <NUM> and each of the cutting laser subsystem <NUM>, the ranging subsystem <NUM>, and the alignment guidance subsystem <NUM>. In many embodiments, the shared optics <NUM> includes beam combiners to receive the emission from the respective subsystem (e.g., the cutting laser subsystem <NUM>, and the alignment guidance subsystem <NUM>) and redirect the emission along the common propagation path to the patient interface. In many embodiments, the shared optics <NUM> includes an objective lens assembly that focuses each laser pulse into a focal point. In many embodiments, the shared optics <NUM> includes scanning mechanisms operable to scan the respective emission in three dimensions. For example, the shared optics can include an XY-scan mechanism(s) and a Z-scan mechanism. The XY-scan mechanism(s) can be used to scan the respective emission in two dimensions transverse to the propagation direction of the respective emission. The Z-scan mechanism can be used to vary the depth of the focal point within the eye <NUM>. In many embodiments, the scanning mechanisms are disposed between the laser diode and the objective lens such that the scanning mechanisms are used to scan the alignment laser beam produced by the laser diode. In contrast, in many embodiments, the video system is disposed between the scanning mechanisms and the objective lens such that the scanning mechanisms do not affect the image obtained by the video system.

The patient interface <NUM> is used to restrain the position of the patient's eye <NUM> relative to the system <NUM>. In many embodiments, the patient interface <NUM> employs a suction ring that is vacuum attached to the patient's eye <NUM>. The suction ring is then coupled with the patient interface <NUM>, for example, using vacuum to secure the suction ring to the patient interface <NUM>. In many embodiments, the patient interface <NUM> includes an optically transmissive structure having a posterior surface that is displaced vertically from the anterior surface of the patient's cornea and a region of a suitable liquid (e.g., a sterile buffered saline solution (BSS) such as Alcon BSS (Alcon Part Number <NUM>-<NUM>-<NUM>) or equivalent) is disposed between and in contact with the posterior surface and the patient's cornea and forms part of a transmission path between the shared optics <NUM> and the patient's eye <NUM>. The optically transmissive structure may comprise a lens <NUM> having one or more curved surfaces. Alternatively, the patient interface <NUM> may comprise an optically transmissive structure having one or more substantially flat surfaces such as a parallel plate or wedge. In many embodiments, the patient interface lens is disposable and can be replaced at any suitable interval, such as before each eye treatment.

The control electronics <NUM> controls the operation of and can receive input from the cutting laser subsystem <NUM>, the ranging subsystem <NUM>, the alignment guidance subsystem <NUM>, the patient interface <NUM>, the control panel/GUI <NUM>, and the user interface devices <NUM> via the communication paths <NUM>. The communication paths <NUM> can be implemented in any suitable configuration, including any suitable shared or dedicated communication paths between the control electronics <NUM> and the respective system components.

The control electronics <NUM> can include any suitable components, such as one or more processor, one or more field-programmable gate array (FPGA), and one or more memory storage devices. In many embodiments, the control electronics <NUM> controls the control panel/GUI <NUM> to provide for pre-procedure planning according to user specified treatment parameters as well as to provide user control over the laser eye surgery procedure.

The control electronics <NUM> may comprise a processor/controller <NUM> (referred to herein as a processor) that is used to perform calculations related to system operation and provide control signals to the various system elements. A computer readable medium <NUM> (also referred to as a database or a memory) is coupled to the processor <NUM> in order to store data used by the processor and other system elements. The processor <NUM> interacts with the other components of the system as described more fully throughout the present specification. In an embodiment, the memory <NUM> can include a look up table that can be utilized to control one or more components of the laser system as described herein.

The processor <NUM> can be a general purpose microprocessor configured to execute instructions and data, such as a Pentium processor manufactured by the Intel Corporation of Santa Clara, California. It can also be an Application Specific Integrated Circuit (ASIC) that embodies at least part of the instructions for performing a method not being part of the invention of the present disclosure in software, firmware and/or hardware. As an example, such processors include dedicated circuitry, ASICs, combinatorial logic, other programmable processors, combinations thereof, and the like.

The memory <NUM> can be local or distributed as appropriate to the particular application. Memory <NUM> may include a number of memories including a main random access memory (RAM) for storage of instructions and data during program execution and a read only memory (ROM) in which fixed instructions are stored. Thus, memory <NUM> provides persistent (non- volatile) storage for program and data files, and may include a hard disk drive, flash memory, a floppy disk drive along with associated removable media, a Compact Disk Read Only Memory (CD-ROM) drive, an optical drive, removable media cartridges, and other like storage media.

The user interface devices <NUM> can include any suitable user input device suitable to provide user input to the control electronics <NUM>. For example, the user interface devices <NUM> can include devices such as, for example, the dual function footswitch <NUM>, the laser footswitch <NUM>, the docking control keypad <NUM>, the patient interface radio frequency identification (RFID) reader <NUM>, the emergency laser stop button <NUM>, the key switch <NUM>, and the patient chair joystick control <NUM>.

<FIG> is a simplified block diagram illustrating an assembly <NUM>, in accordance with many embodiments, that can be included in the system <NUM>. The assembly <NUM> is a non-limiting example of suitable configurations and integration of the cutting laser subsystem <NUM>, the ranging subsystem <NUM>, the alignment guidance subsystem <NUM>, the shared optics <NUM>, and the patient interface <NUM>. Other configurations and integration of the cutting laser subsystem <NUM>, the ranging subsystem <NUM>, the alignment guidance subsystem <NUM>, the shared optics <NUM>, and the patient interface <NUM> may be possible and may be apparent to a person of skill in the art.

The assembly <NUM> is operable to project and scan optical beams into the patient's eye <NUM>. The cutting laser subsystem <NUM> includes an ultrafast (UF) laser <NUM> (e.g., a femtosecond laser). Using the assembly <NUM>, optical beams can be scanned in the patient's eye <NUM> in three dimensions: X, Y, Z. For example, short-pulsed laser light generated by the UF laser <NUM> can be focused into eye tissue to produce dielectric breakdown to cause photodisruption around the focal point (the focal zone), thereby rupturing the tissue in the vicinity of the photo-induced plasma. In the assembly <NUM>, the wavelength of the laser light can vary between <NUM> to <NUM> and the pulse width of the laser light can vary from 10fs to 10000fs. The pulse repetition frequency can also vary from <NUM> to <NUM>. Safety limits with regard to unintended damage to non-targeted tissue bound the upper limit with regard to repetition rate and pulse energy. Threshold energy, time to complete the procedure, and stability can bound the lower limit for pulse energy and repetition rate. The peak power of the focused spot in the eye <NUM> and specifically within the crystalline lens and the lens capsule of the eye is sufficient to produce optical breakdown and initiate a plasma-mediated ablation process. Near-infrared wavelengths for the laser light are preferred because linear optical absorption and scattering in biological tissue is reduced for near-infrared wavelengths. As an example, the laser <NUM> can be a repetitively pulsed <NUM> device that produces pulses with less than <NUM> fs duration at a repetition rate of <NUM> (+/- <NUM>%) and individual pulse energy in the <NUM> to <NUM> micro joule range.

The cutting laser subsystem <NUM> is controlled by the control electronics <NUM> and the user, via the control panel/GUI <NUM> and the user interface devices <NUM>, to create a laser pulse beam <NUM>. The control panel/GUI <NUM> is used to set system operating parameters, process user input, display gathered information such as images of ocular structures, and display representations of incisions to be formed in the patient's eye <NUM>.

The generated laser pulse beam <NUM> proceeds through a zoom assembly <NUM>. The laser pulse beam <NUM> may vary from unit to unit, particularly when the UF laser <NUM> may be obtained from different laser manufacturers. For example, the beam diameter of the laser pulse beam <NUM> may vary from unit to unit (e.g., by +/- <NUM>%). The beam may also vary with regard to beam quality, beam divergence, beam spatial circularity, and astigmatism. In many embodiments, the zoom assembly <NUM> is adjustable such that the laser pulse beam <NUM> exiting the zoom assembly <NUM> has consistent beam diameter and divergence unit to unit.

After exiting the zoom assembly <NUM>, the laser pulse beam <NUM> proceeds through an attenuator <NUM>. The attenuator <NUM> is used to adjust the transmission of the laser beam and thereby the energy level of the laser pulses in the laser pulse beam <NUM>. The attenuator <NUM> is controlled via the control electronics <NUM>.

After exiting the attenuator <NUM>, the laser pulse beam <NUM> proceeds through an aperture <NUM>. The aperture <NUM> sets the outer useful diameter of the laser pulse beam <NUM>. In turn the zoom determines the size of the beam at the aperture location and therefore the amount of light that is transmitted. The amount of transmitted light is bounded both high and low. The upper is bounded by the requirement to achieve the highest numerical aperture achievable in the eye. High NA promotes low threshold energies and greater safety margin for untargeted tissue. The lower is bound by the requirement for high optical throughput. Too much transmission loss in the system shortens the lifetime of the system as the laser output and system degrades over time. Additionally, consistency in the transmission through this aperture promotes stability in determining optimum settings (and sharing of) for each procedure. Typically to achieve optimal performance the transmission through this aperture as set to be between <NUM>% to <NUM>%.

After exiting the aperture <NUM>, the laser pulse beam <NUM> proceeds through two output pickoffs <NUM>. Each output pickoff <NUM> can include a partially reflecting mirror to divert a portion of each laser pulse to a respective output monitor <NUM>. Two output pickoffs <NUM> (e.g., a primary and a secondary) and respective primary and secondary output monitors <NUM> are used to provide redundancy in case of malfunction of the primary output monitor <NUM>.

After exiting the output pickoffs <NUM>, the laser pulse beam <NUM> proceeds through a system-controlled shutter <NUM>. The system-controlled shutter <NUM> ensures on/off control of the laser pulse beam <NUM> for procedural and safety reasons. The two output pickoffs precede the shutter allowing for monitoring of the beam power, energy, and repetition rate as a pre-requisite for opening the shutter.

After exiting the system-controlled shutter <NUM>, the optical beam proceeds through an optics relay telescope <NUM>. The optics relay telescope <NUM> propagates the laser pulse beam <NUM> over a distance while accommodating positional and/or directional variability of the laser pulse beam <NUM>, thereby providing increased tolerance for component variation. As an example, the optical relay can be a keplerian afocal telescope that relays an image of the aperture position to a conjugate position near to the XY galvo mirror positions. In this way, the position of the beam at the XY galvo location is invariant to changes in the beams angle at the aperture position. Similarly the shutter does not have to precede the relay and may follow after or be included within the relay.

After exiting the optics relay telescope <NUM>, the laser pulse beam <NUM> is transmitted to the shared optics <NUM>, which propagates the laser pulse beam <NUM> to the patient interface <NUM>. The laser pulse beam <NUM> is incident upon a beam combiner <NUM>, which reflects the laser pulse beam <NUM> while transmitting optical beams from the ranging subsystem <NUM> and the alignment guidance subsystem: AIM <NUM>.

Following the beam combiner <NUM>, the laser pulse beam <NUM> continues through a Z-telescope <NUM>, which is operable to scan focus position of the laser pulse beam <NUM> in the patient's eye <NUM> along the Z axis. For example, the Z-telescope <NUM> can include a Galilean telescope with two lens groups (each lens group includes one or more lenses). One of the lens groups moves along the Z axis about the collimation position of the Z-telescope <NUM>. In this way, the focus position of the spot in the patient's eye <NUM> moves along the Z axis. In general, there is a relationship between the motion of lens group and the motion of the focus point. For example, the Z-telescope can have an approximate 2x beam expansion ratio and close to a <NUM>:<NUM> relationship of the movement of the lens group to the movement of the focus point. The exact relationship between the motion of the lens and the motion of the focus in the Z axis of the eye coordinate system does not have to be a fixed linear relationship. The motion can be nonlinear and directed via a model or a calibration from measurement or a combination of both. Alternatively, the other lens group can be moved along the Z axis to adjust the position of the focus point along the Z axis. The Z-telescope <NUM> functions as a Z-scan device for scanning the focus point of the laser-pulse beam <NUM> in the patient's eye <NUM>. The Z-telescope <NUM> can be controlled automatically and dynamically by the control electronics <NUM> and selected to be independent or to interplay with the X- and Y-scan devices described next.

After passing through the Z-telescope <NUM>, the laser pulse beam <NUM> is incident upon an X-scan device <NUM>, which is operable to scan the laser pulse beam <NUM> in the X direction, which is dominantly transverse to the Z axis and transverse to the direction of propagation of the laser pulse beam <NUM>. The X-scan device <NUM> is controlled by the control electronics <NUM>, and can include suitable components, such as a motor, galvanometer, or any other well-known optic moving device. The relationship of the motion of the beam as a function of the motion of the X actuator does not have to be fixed or linear. Modeling or calibrated measurement of the relationship or a combination of both can be determined and used to direct the location of the beam.

After being directed by the X-scan device <NUM>, the laser pulse beam <NUM> is incident upon a Y-scan device <NUM>, which is operable to scan the laser pulse beam <NUM> in the Y direction, which is dominantly transverse to the X and Z axes. The Y-scan device <NUM> is controlled by the control electronics <NUM>, and can include suitable components, such as a motor, galvanometer, or any other well-known optic moving device. The relationship of the motion of the beam as a function of the motion of the Y actuator does not have to be fixed or linear. Modeling or calibrated measurement of the relationship or a combination of both can be determined and used to direct the location of the beam. Alternatively, the functionality of the X-scan device <NUM> and the Y-scan device <NUM> can be provided by an XY-scan device configured to scan the laser pulse beam <NUM> in two dimensions transverse to the Z axis and the propagation direction of the laser pulse beam <NUM>. The X-scan and Y-scan devices <NUM>, <NUM> change the resulting direction of the laser pulse beam <NUM>, causing lateral displacements of UF focus point located in the patient's eye <NUM>.

After being directed by the Y-scan device <NUM>, the laser pulse beam <NUM> passes through a beam combiner <NUM>. The beam combiner <NUM> is configured to transmit the laser pulse beam <NUM> while reflecting optical beams to and from a video subsystem <NUM> of the alignment guidance subsystem <NUM>.

After passing through the beam combiner <NUM>, the laser pulse beam <NUM> passes through an objective lens assembly <NUM>. The objective lens assembly <NUM> can include one or more lenses. In many embodiments, the objective lens assembly <NUM> includes multiple lenses. The complexity of the objective lens assembly <NUM> may be driven by the scan field size, the focused spot size, the degree of telecentricity, the available working distance on both the proximal and distal sides of objective lens assembly <NUM>, as well as the amount of aberration control.

After passing through the objective lens assembly <NUM>, the laser pulse beam <NUM> passes through the patient interface <NUM>. As described above, in many embodiments, the patient interface <NUM> includes a patient interface lens <NUM> having a posterior surface that is displaced vertically from the anterior surface of the patient's cornea and a region of a suitable liquid (e.g., a sterile buffered saline solution (BSS) such as Alcon BSS (Alcon Part Number <NUM>-<NUM>-<NUM>) or equivalent) is disposed between and in contact with the posterior surface of the patient interface lens <NUM> and the patient's cornea and forms part of an optical transmission path between the shared optics <NUM> and the patient's eye <NUM>.

The shared optics <NUM> under the control of the control electronics <NUM> can automatically generate aiming, ranging, and treatment scan patterns. Such patterns can be comprised of a single spot of light, multiple spots of light, a continuous pattern of light, multiple continuous patterns of light, and/or any combination of these. In addition, the aiming pattern (using the aim beam <NUM> described below) need not be identical to the treatment pattern (using the laser pulse beam <NUM>), but can optionally be used to designate the boundaries of the treatment pattern to provide verification that the laser pulse beam <NUM> will be delivered only within the desired target area for patient safety. This can be done, for example, by having the aiming pattern provide an outline of the intended treatment pattern. This way the spatial extent of the treatment pattern can be made known to the user, if not the exact locations of the individual spots themselves, and the scanning thus optimized for speed, efficiency, and/or accuracy. The aiming pattern can also be made to be perceived as blinking in order to further enhance its visibility to the user. Likewise, the ranging beam <NUM> need not be identical to the treatment beam or pattern. The ranging beam needs only to be sufficient enough to identify targeted surfaces. These surfaces can include the cornea and the anterior and posterior surfaces of the lens and may be considered spheres with a single radius of curvature. Also the optics shared by the alignment guidance: video subsystem does not have to be identical to those shared by the treatment beam. The positioning and character of the laser pulse beam <NUM> and/or the scan pattern the laser pulse beam <NUM> forms on the eye <NUM> may be further controlled by use of an input device such as a joystick, or any other appropriate user input device (e.g., control panel/GUI <NUM>) to position the patient and/or the optical system.

The control electronics <NUM> can be configured to target the targeted structures in the eye <NUM> and ensure that the laser pulse beam <NUM> will be focused where appropriate and not unintentionally damage non-targeted tissue. Imaging modalities and techniques described herein, such as those mentioned above, or ultrasound may be used to determine the location and measure the thickness of the lens and lens capsule to provide greater precision to the laser focusing methods, including 2D and 3D patterning. Laser focusing may also be accomplished by using one or more methods including direct observation of an aiming beam, or other known ophthalmic or medical imaging modalities, such as those mentioned above, and/or combinations thereof. Additionally the ranging subsystem such as an OCT can be used to detect features or aspects involved with the patient interface. Features can include fiducials placed on the docking structures and optical structures of the disposable lens such as the location of the anterior and posterior surfaces.

In the embodiment of <FIG>, the ranging subsystem <NUM> includes an OCT imaging device. Additionally or alternatively, imaging modalities other than OCT imaging can be used. An OCT scan of the eye can be used to measure the spatial disposition (e.g., three dimensional coordinates such as X, Y, and Z of points on boundaries) of structures of interest in the patient's eye <NUM>. Such structure of interest can include, for example, the anterior surface of the cornea, the posterior surface of the cornea, the anterior portion of the lens capsule, the posterior portion of the lens capsule, the anterior surface of the crystalline lens, the posterior surface of the crystalline lens, the iris, the pupil, and/or the limbus. The spatial disposition of the structures of interest and/or of suitable matching geometric modeling such as surfaces and curves can be generated and/or used by the control electronics <NUM> to program and control the subsequent laser-assisted surgical procedure. The spatial disposition of the structures of interest and/or of suitable matching geometric modeling can also be used to determine a wide variety of parameters related to the procedure such as, for example, the upper and lower axial limits of the focal planes used for cutting the lens capsule and segmentation of the lens cortex and nucleus, and the thickness of the lens capsule among others. Additionally the ranging subsystem such as an OCT can be used to detect features or aspects involved with the patient interface. Features can include fiducials placed on the docking structures and optical structures of the disposable lens such as the location of the anterior and posterior surfaces.

The ranging subsystem <NUM> in <FIG> includes an OCT light source and detection device <NUM>. The OCT light source and detection device <NUM> includes a light source that generates and emits an OCT source beam with a suitable broad spectrum. For example, in many embodiments, the OCT light source and detection device <NUM> generates and emits the OCT source beam with a broad spectrum from <NUM> to <NUM> wavelength. The generated and emitted light is coupled to the device <NUM> by a single mode fiber optic connection.

The OCT source beam emitted from the OCT light source and detection device <NUM> is passed through a pickoff/combiner assembly <NUM>, which divides the OCT source beam into a sample beam <NUM> and a reference portion <NUM>. A significant portion of the sample beam <NUM> is transmitted through the shared optics <NUM>. A relative small portion of the sample beam is reflected from the patient interface <NUM> and/or the patient's eye <NUM> and travels back through the shared optics <NUM>, back through the pickoff/combiner assembly <NUM> and into the OCT light source and detection device <NUM>. The reference portion <NUM> is transmitted along a reference path <NUM> having an adjustable path length. The reference path <NUM> is configured to receive the reference portion <NUM> from the pickoff/combiner assembly <NUM>, propagate the reference portion <NUM> over an adjustable path length, and then return the reference portion <NUM> back to the pickoff/combiner assembly <NUM>, which then directs the returned reference portion <NUM> back to the OCT light source and detection device <NUM>. The OCT light source and detection device <NUM> then directs the returning small portion of the sample beam <NUM> and the returning reference portion <NUM> into a detection assembly, which employs a time domain detection technique, a frequency detection technique, or a single point detection technique. For example, a frequency domain technique can be used with an OCT wavelength of <NUM> and bandwidth of <NUM>.

Once combined with the UF laser pulse beam <NUM> subsequent to the beam combiner <NUM>, the OCT sample beam <NUM> follows a shared path with the UF laser pulse beam <NUM> through the shared optics <NUM> and the patient interface <NUM>. In this way, the OCT sample beam <NUM> is generally indicative of the location of the UF laser pulse beam <NUM>. Similar to the UF laser beam, the OCT sample beam <NUM> passes through the Z-telescope <NUM>, is redirected by the X-scan device <NUM> and by the Y-scan device <NUM>, passes through the objective lens assembly <NUM> and the patient interface <NUM>, and on into the eye <NUM>. Reflections and scatter off of structures within the eye provide return beams that retrace back through the patient interface <NUM>, back through the shared optics <NUM>, back through the pickoff/combiner assembly <NUM>, and back into the OCT light source and detection device <NUM>. The returning back reflections of the sample beam <NUM> are combined with the returning reference portion <NUM> and directed into the detector portion of the OCT light source and detection device <NUM>, which generates OCT signals in response to the combined returning beams. The generated OCT signals that are in turn interpreted by the control electronics to determine the spatial disposition of the structures of interest in the patient's eye <NUM>. The generated OCT signals can also be interpreted by the control electronics to measure the position and orientation of the patient interface <NUM>, as well as to determine whether there is liquid disposed between the posterior surface of the patient interface lens <NUM> and the patient's eye <NUM>.

The OCT light source and detection device <NUM> works on the principle of measuring differences in optical path length between the reference path <NUM> and the sample path. Therefore, different settings of the Z-telescope <NUM> to change the focus of the UF laser beam do not impact the length of the sample path for an axially stationary surface in the eye of patient interface volume because the optical path length does not change as a function of different settings of the Z-telescope <NUM>. The ranging subsystem <NUM> has an inherent Z range that is related to the light source and detection scheme, and in the case of frequency domain detection the Z range is specifically related to the spectrometer, the wavelength, the bandwidth, and the length of the reference path <NUM>. In the case of ranging subsystem <NUM> used in <FIG>, the Z range is approximately <NUM>-<NUM> in an aqueous environment. Extending this range to at least <NUM>-<NUM> involves the adjustment of the path length of the reference path via a stage ZED <NUM> within ranging subsystem <NUM>. Passing the OCT sample beam <NUM> through the Z-telescope <NUM>, while not impacting the sample path length, allows for optimization of the OCT signal strength. This is accomplished by focusing the OCT sample beam <NUM> onto the targeted structure. The focused beam both increases the return reflected or scattered signal that can be transmitted through the single mode fiber and increases the spatial resolution due to the reduced extent of the focused beam. The changing of the focus of the sample OCT beam can be accomplished independently of changing the path length of the reference path <NUM>.

Because of the fundamental differences in how the sample beam <NUM> (e.g., <NUM> to <NUM> wavelengths) and the UF laser pulse beam <NUM> (e.g., <NUM> to <NUM> wavelengths) propagate through the shared optics <NUM> and the patient interface <NUM> due to influences such as immersion index, refraction, and aberration, both chromatic and monochromatic, care must be taken in analyzing the OCT signal with respect to the UF laser pulse beam <NUM> focal location. A calibration or registration procedure as a function of X, Y, and Z can be conducted in order to match the OCT signal information to the UF laser pulse beam focus location and also to the relative to absolute dimensional quantities.

There are many suitable possibilities for the configuration of the OCT interferometer. For example, alternative suitable configurations include time and frequency domain approaches, single and dual beam methods, swept source, etc., are described in U. <NUM>,<NUM>,<NUM>; <NUM>,<NUM>,<NUM>; <NUM>,<NUM>,<NUM>; <NUM>,<NUM>,<NUM>; and <NUM>,<NUM>,<NUM>.

The system <NUM> can be set to locate the anterior and posterior surfaces of the lens capsule and cornea and ensure that the UF laser pulse beam <NUM> will be focused on the lens capsule and cornea at all points of the desired opening. Imaging modalities and techniques described herein, such as for example, Optical Coherence Tomography (OCT), and such as Purkinje imaging, Scheimpflug imaging, confocal or nonlinear optical microscopy, fluorescence imaging, ultrasound, structured light, stereo imaging, or other known ophthalmic or medical imaging modalities and/or combinations thereof may be used to determine the shape, geometry, perimeter, boundaries, and/or <NUM>-dimensional location of the lens and lens capsule and cornea to provide greater precision to the laser focusing methods, including 2D and 3D patterning. Laser focusing may also be accomplished using one or more methods including direct observation of an aiming beam, or other known ophthalmic or medical imaging modalities and combinations thereof, such as but not limited to those defined above.

Optical imaging of the cornea, anterior chamber, and lens can be performed using the same laser and/or the same scanner used to produce the patterns for cutting. Optical imaging can be used to provide information about the axial location and shape (and even thickness) of the anterior and posterior lens capsule, the boundaries of the cataract nucleus, as well as the depth of the anterior chamber and features of the cornea. This information may then be loaded into the laser <NUM>-D scanning system or used to generate a three dimensional model/representation/image of the cornea, anterior chamber, and lens of the eye, and used to define the cutting patterns used in the surgical procedure.

Observation of an aim beam can also be used to assist in positioning the focus point of the UF laser pulse beam <NUM>. Additionally, an aim beam visible to the unaided eye in lieu of the infrared OCT sample beam <NUM> and the UF laser pulse beam <NUM> can be helpful with alignment provided the aim beam accurately represents the infrared beam parameters. The alignment guidance subsystem <NUM> is included in the assembly <NUM> shown in <FIG>. An aim beam <NUM> is generated by an aim beam light source <NUM>, such as a laser diode in the <NUM>-<NUM> range.

Once the aim beam light source <NUM> generates the aim beam <NUM>, the aim beam <NUM> is transmitted along an aim path <NUM> to the shared optics <NUM>, where it is redirected by a beam combiner <NUM>. After being redirected by the beam combiner <NUM>, the aim beam <NUM> follows a shared path with the UF laser pulse beam <NUM> through the shared optics <NUM> and the patient interface <NUM>. In this way, the aim beam <NUM> is indicative of the location of the UF laser pulse beam <NUM>. The aim beam <NUM> passes through the Z-telescope <NUM>, is redirected by the X-scan device <NUM> and by the Y-scan device <NUM>, passes through the beam combiner <NUM>, passes through the objective lens assembly <NUM> and the patient interface <NUM>, and on into the patient's eye <NUM>.

The video subsystem <NUM> is operable to obtain images of the patient interface and the patient's eye. The video subsystem <NUM> includes a camera <NUM>, an illumination light source <NUM>, and a beam combiner <NUM>. The video subsystem <NUM> gathers images that can be used by the control electronics <NUM> for providing pattern centering about or within a predefined structure. The illumination light source <NUM> can be generally broadband and incoherent. For example, the light source <NUM> can include multiple LEDs. The wavelength of the illumination light source <NUM> is preferably in the range of <NUM> to <NUM>, but can be anything that is accommodated by the beam combiner <NUM>, which combines the light from the illumination light source <NUM> with the beam path for the UF laser pulse beam <NUM>, the OCT sample beam <NUM>, and the aim beam <NUM> (beam combiner <NUM> reflects the video wavelengths while transmitting the OCT and UF wavelengths). The beam combiner <NUM> may partially transmit the aim beam <NUM> wavelength so that the aim beam <NUM> can be visible to the camera <NUM>. An optional polarization element can be disposed in front of the illumination light source <NUM> and used to optimize signal. The optional polarization element can be, for example, a linear polarizer, a quarter wave plate, a half-wave plate or any combination. An additional optional analyzer can be placed in front of the camera. The polarizer analyzer combination can be crossed linear polarizers thereby eliminating specular reflections from unwanted surfaces such as the objective lens surfaces while allowing passage of scattered light from targeted surfaces such as the intended structures of the eye. The illumination may also be in a dark-field configuration such that the illumination sources are directed to the independent surfaces outside the capture numerical aperture of the image portion of the video system. Alternatively the illumination may also be in a bright field configuration. In both the dark and bright field configurations, the illumination light source maybe be used as a fixation beam for the patient. The illumination may also be used to illuminate the patient's pupil to enhance the pupil iris boundary to facilitate iris detection and eye tracking. A false color image generated by the near infrared wavelength or a bandwidth thereof may be acceptable.

The illumination light from the illumination light source <NUM> is transmitted through the beam combiner <NUM> to the beam combiner <NUM>. From the beam combiner <NUM>, the illumination light is directed towards the patient's eye <NUM> through the objective lens assembly <NUM> and through the patient interface <NUM>. The illumination light reflected and scattered off of various structures of the eye <NUM> and patient interface travel back through the patient interface <NUM>, back through the objective lens assembly <NUM>, and back to the beam combiner <NUM>. At the beam combiner <NUM>, the returning light is directed back to the beam combiner <NUM> where the returning light is redirected toward the camera <NUM>. The beam combiner can be a cube, plate, or pellicle element. It may also be in the form of a spider mirror whereby the illumination transmits past the outer extent of the mirror while the image path reflects off the inner reflecting surface of the mirror. Alternatively, the beam combiner could be in the form of a scraper mirror where the illumination is transmitted through a hole while the image path reflects off of the mirrors reflecting surface that lies outside the hole. The camera <NUM> can be an suitable imaging device, for example but not limited to, any silicon based detector array of the appropriately sized format. A video lens forms an image onto the camera's detector array while optical elements provide polarization control and wavelength filtering respectively. An aperture or iris provides control of imaging NA and therefore depth of focus and depth of field and resolution. A small aperture provides the advantage of large depth of field that aids in the patient docking procedure. Alternatively, the illumination and camera paths can be switched. Furthermore, the aim light source <NUM> can be made to emit infrared light that would not be directly visible, but could be captured and displayed using the video subsystem <NUM>.

In the embodiment of <FIG>, <FIG>, and <FIG>, the cutting laser subsystem <NUM> includes the ultrafast (UF) laser <NUM>, the zoom assembly <NUM>, the polarizer and beam dump <NUM>, the output pickoffs <NUM>, the output monitors <NUM>, the system-controlled shutter <NUM>, and the optics relay telescope <NUM>. The cutting laser subsystem <NUM> further includes mirrors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, a periscope <NUM>, a one-half wave plate <NUM>, and an aperture <NUM>. The mirrors <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are used to route the laser pulse beam <NUM> (treatment beam) from the ultrafast (UF) laser <NUM> to the beam combiner <NUM>. The periscope <NUM> provides an adjustable means to align the laser pulse beam <NUM> output by the ultrafast (UF) laser <NUM> with the downstream optical path through the downstream portion of the cutting laser subsystem <NUM>, the shared optics <NUM>, the patient interface <NUM>, and into the eye <NUM>. The aperture <NUM> sets an outer useful diameter for the laser pulse beam <NUM>.

The laser pulse beam <NUM> passes through the zoom assembly <NUM>. The zoom assembly can be operable to modify beam parameters such as beam diameter, divergence, circularity, and astigmatism. For example, the zoom assembly <NUM> illustrated in <FIG> is adjustable and includes a three optical element assembly that is adjustable to achieve intended beam size and collimation. Although not illustrated here, an anamorphic or other optical system can be used to achieve desired beam parameters. The factors used to determine suitable beam parameters include the output beam parameters of the laser, the overall magnification of the system, and the desired numerical aperture (NA) at the treatment location. In addition, the zoom assembly <NUM> can be used to image a laser waist location or other preferred plane within the laser assembly <NUM> to the aperture <NUM> location, shown in <FIG>, for example. The aperture is then imaged by relay <NUM> to a center location between the X-scan device <NUM> and the Y-scan device <NUM>, shown in <FIG>. In this way, the beam at the desired location in the laser such as a waist of stable location is placed at the aperture and the portion of the laser pulse beam <NUM> that makes it through the aperture <NUM> is assured to make it through the shared optics <NUM>.

After exiting the zoom assembly <NUM>, the laser pulse beam <NUM> is reflected by the mirror <NUM> and the mirror <NUM> and then passes through the one-half wave plate <NUM> before passing through the polarizer <NUM>. The beam exiting the laser is linearly polarized. The ½ wave plate can rotate this polarization. The amount of light passing through the polarizer depends on the angle of the rotation of the linear polarization. Therefore the ½ w plate with the polarizer acts as an attenuator of the beam that is transmitted through towards the shared optics. The rejected light from this attenuation method is directed into the beam dump. After exiting the one-half wave plate <NUM> and polarizer <NUM> combination, the laser pulse beam <NUM> passes through the aperture <NUM>, through the output pickoffs <NUM>, and through the optics relay telescope <NUM> and the system-controlled shutter <NUM>. By locating the system-controlled shutter <NUM> downstream of the output pickoffs and monitors <NUM>, <NUM>, the power of the laser pulse beam <NUM> can be checked before opening the system-controlled shutter <NUM>. After exiting the optics relay telescope <NUM>, the laser pulse beam <NUM> is reflected by the mirror <NUM> and the mirror <NUM>. The mirrors <NUM>, <NUM>, <NUM>, <NUM>, <NUM> in the cutting laser subsystem <NUM> can include a coating(s) to control dispersion so as to prevent broadening of the temporal pulse width. The beam combiner <NUM> then reflects the laser pulse beam <NUM> so as to be directed through the shared optics <NUM>.

In the embodiment of <FIG>, <FIG>, and <FIG> the ranging subsystem <NUM> includes the OCT light source and detection device <NUM>, the pickoff/combiner assembly <NUM>, and the reference path <NUM>. The OCT light source and detection device <NUM> emits the OCT source beam <NUM>, which propagates to the pickoff/combiner assembly <NUM> through a single mode optical fiber <NUM> and an optical fiber connector <NUM>. The OCT source beam <NUM> is collimated using a lens <NUM> and proceeds towards the pickoff/combiner assembly <NUM>. The function of the pickoff/combiner assembly <NUM> is to split the OCT source beam <NUM> into two separate beams (i.e., the sample beam <NUM> and the reference beam <NUM>). The sample beam <NUM> propagates along an optical path referred to as a sample path. The reference beam <NUM> propagates along an optical path referred to as the reference path <NUM>. As described herein, the sample beam <NUM> propagates to the eye <NUM> and is retro reflected or scattered back through the sample path to the pickoff/combiner assembly <NUM>.

The reference beam <NUM> propagates away from and back to the pickoff/combiner assembly <NUM> along the reference path <NUM>. The reference path <NUM> has an adjustable optical path length to extend the measurement range within the eye of the ranging subsystem <NUM>. After leaving the pickoff/combiner assembly <NUM>, the reference beam <NUM> is reflected by a mirror <NUM> so as to pass through an OCT quarter-wave plate <NUM>. After exiting the OCT quarter-wave plate <NUM>, the reference beam <NUM> is reflected by a mirror <NUM> so as to pass lengthwise through a glass rod <NUM>. The material and the length of the glass rod <NUM> are selected to balance dispersion between the sample path and the reference path <NUM>. After exiting the glass rod <NUM>, the reference beam <NUM> passes through an aperture <NUM> and is then reflected by mirrors <NUM>, <NUM> so as to be directed into a reference path length adjustment mechanism <NUM>, which is repositionable along a direction <NUM>. The mechanism <NUM> includes two mirrors <NUM> and <NUM>, which are repositioned along the direction <NUM> by repositioning the mechanism <NUM> along the direction <NUM>. The reference beam <NUM> entering the mechanism <NUM> is reflected by the mirrors <NUM>, <NUM>. After exiting the mechanism <NUM>, the reference beam <NUM> is reflected by a mirror <NUM> so as to be directed through a dispersion element <NUM>, which in combination with the glass rod <NUM> is selected to balance dispersion between the sample path and the reference path <NUM>. After exiting the dispersion element <NUM>, the reference beam <NUM> passes through a focusing lens <NUM> and is reflected by a mirror <NUM> toward a retro mirror <NUM>. The retro mirror <NUM> retro-reflects the reference beam back along the reference path <NUM> to the pickoff/combiner assembly <NUM>. The returning sample and reference beams are then combined by the pickoff/combiner assembly <NUM>. The combined beams with embedded signal information is then directed back through the optical fiber <NUM> to the OCT light source and detection device <NUM> where the combined beams are detected.

Referring now to <FIG>, the pickoff/combiner assembly <NUM> is described relative to dividing the OCT source beam <NUM> into the sample beam <NUM> and the reference beam <NUM>. The division of the OCT source beam <NUM> is referred to herein as the pickoff mode. The pickoff/combiner assembly <NUM> also functions in what is referred to herein as the combiner mode in which the returning portion of the sample beam <NUM> and the returning reference beam <NUM> are combined and directed back to the OCT light source and detection device <NUM>. The combiner mode works similar to the pickoff mode, but in reverse.

The pickoff/combiner assembly <NUM> includes a first optical wedge <NUM> and a second optical wedge <NUM>. The OCT source beam <NUM> passes through the first optical wedge <NUM> and into the second optical wedge <NUM>. The first optical wedge <NUM> has an anterior surface <NUM> and a posterior surface <NUM>. The second optical wedge <NUM> has an anterior surface <NUM> and a posterior surface <NUM>. The OCT source beam <NUM> enters the first optical wedge <NUM> through the anterior surface <NUM> and exits the first optical wedge <NUM> through the posterior surface <NUM>. The OCT source beam <NUM> then enters the second optical wedge <NUM> through the anterior surface <NUM>. The OCT source beam <NUM> is then partially reflected by the second optical wedge posterior surface <NUM>. The portion of the OCT source beam <NUM> that is reflected by the posterior surface <NUM> becomes the reference beam <NUM>. The portion of the OCT source beam <NUM> that passes through the posterior surface <NUM> becomes the sample beam <NUM>. In the embodiment illustrated, each of the first and second optical wedges <NUM>, <NUM> have a wedge angle <NUM> of <NUM> degrees. A suitable material for the first and second optical wedges <NUM>, <NUM> can be selected. For example, the first and second optical wedges can be made from a high refractive index glass (e.g., Schott NSF6 with a refractive index of <NUM> at wavelength <NUM>).

The first and second wedges <NUM> and <NUM> are configured to counter-act prism dispersion and color aberration that would result if only one optical wedge was used. Passing either the sample beam <NUM> or the reference beam <NUM> through a single wedge would result in prism dispersion and color aberration due to the broad bandwidth (e.g., <NUM> to <NUM>) of the OCT source beam <NUM>. The wedge angles of the first and second optical wedges <NUM>, <NUM> are therefore opposing. In this way, each of the OCT source beams <NUM>, the reference beam <NUM>, and returning portion of the sample beam <NUM> experiences offsetting wedges effects because the beams pass thru both of the first and second optical wedges <NUM>, <NUM>. For example, the reference beam <NUM> experiences this cancellation of the wedge effect because the reference beam <NUM> reflects off the second optical wedge posterior surface <NUM> and then propagates through the second optical wedge <NUM> and then through the offsetting first optical wedge <NUM>.

In many embodiments, the OCT source beam <NUM> is generally unpolarized. The returning portion of the sample beam <NUM>, however, may have any polarization including pure s-polarized, pure p-polarized or a combination of both. The polarization of the returning portion of the sample beam <NUM> is an uncontrolled variable due to polarization effects imparted by the eye <NUM>. For example, birefringence of the cornea can impart polarization to the returning portion of the sample beam <NUM>. The polarization effects caused by the eye may be dependent on position of the sample beam <NUM> within the eye <NUM> and subject to anatomical differences. Similar to an interferometer, the OCT light source and detection device <NUM> generates an OCT signal based on interference between the returning portion of the sample beam <NUM> and the reference beam <NUM>. To achieve signal and contrast, the reference beam <NUM> preferably contains both polarization states. Additionally, the polarization of the source beam <NUM> can vary depending on the light source used and fiber optic orientation. This can vary from source to source. The purpose of the <NUM>/4w plate in the reference path is to ensure that a proper amount of both s and p polarization with respect to the sample beam are present in order to generate signal. An extreme example is the source beam may be linearly polarized in the p-direction. This p-polarized light may be completely converted to s-polarized light due to uncontrolled anatomical effects upon return in the sample path. Meanwhile in the reference path without a <NUM>/4w plate the p-polarization is preserved. Upon combining the sample and reference paths, the crossed polarized beams would fail to produce a signal. Introduction of a <NUM>/4w plate in the reference beam can convert the p-polarized light into s-polarized reference return light and therefore produce a signal. The <NUM>/4w plate is adjustable in rotation about its Z axis (clocking). Adjustment can be made on a system to system basis to optimize return signal.

In many embodiments, the pickoff/combiner assembly <NUM> is configured to minimize polarization effects or differences due to beam polarization. For example, as illustrated in Table <NUM>, the illustrated embodiment of the pickoff/combiner assembly <NUM> is configured to minimize the angle of incidence of the beams (OCT source beam <NUM>, sample beam <NUM>, and reference beam <NUM>) at all of the optical wedge surfaces <NUM>, <NUM>, <NUM>, and in particular at surface <NUM> so as to minimize polarization effects.

The offsetting first and second optical wedges <NUM>, <NUM>, the low angle of incidence of the beams <NUM>, <NUM>, <NUM> relative to the surfaces <NUM>, <NUM>, <NUM>, <NUM>, and resulting generation of the OCT signal are important aspects relative to the configuration of the pickoff/combiner assembly <NUM>. For example, a separation <NUM> between the first and second optical wedges <NUM>, <NUM> is preferably greater than the detection range of the OCT light source and detection device <NUM> for a given length of the reference path <NUM> so as to reduce and/or eliminate etalon effects from the OCT signal. For example, the OCT detection range can be <NUM> in air and the separation <NUM> can be larger than <NUM> (e.g., <NUM> or larger). The etalon effect can be further mitigated by tilting the first and second wedges <NUM>, <NUM> relative to each other. For example, in the illustrated embodiment, an angle <NUM> of the second optical wedge anterior surface <NUM> is <NUM> degrees relative to a normal to the first optical wedge posterior surface <NUM> so that the surfaces <NUM>, <NUM> are tilted by one degree relative to each other. Although the illustrated embodiment uses a tilt angle of one degree between the surfaces <NUM>, <NUM>, any suitable tilt angle can be used.

Because of the low angle of the reference beam <NUM> relative to the OCT source beam <NUM>, a certain amount of distance is required before the reference beam <NUM> is sufficiently separated from the OCT source beam <NUM> to accommodate the mirror <NUM>. For example, a distance <NUM> (e.g., <NUM>) parallel to the OCT source beam <NUM> and a distance <NUM> (e.g., <NUM>) perpendicular to the OCT source beam <NUM> can be used to provide adequate room for the mirror <NUM>. Because the length of the reference path <NUM> is adjusted to match the sample path length, distances <NUM>, <NUM> must be accounted for in configuring the reference path <NUM>. The separation of the first and second optical wedges <NUM>, <NUM> along with associated wedge and tilt angles cause an offset <NUM> between the OCT source beam <NUM> and the sample beam <NUM>. The offset <NUM> must also be accounted for with respect to positioning optical elements between the pickoff/detection assembly <NUM> and the beam combiner <NUM>.

The second optical wedge posterior surface <NUM> is the beam combining surface of the pickoff/detection assembly <NUM>. The surface <NUM> is uncoated so as to assure reliable reflectivity by eliminating any possible coating degradation related reflectivity changes. The angle of incidence at the surface <NUM> is small to reduce the difference in reflectivity for s and p polarizations. It is important to control the amount of light split between the reference and sample paths. To achieve good signal (as in an interferometer) there is preferably balance in the intensity of the light from both paths. The returning portion of the sample beam <NUM> is the amount of return generated by reflections and scatter off of a target (e.g., a structure in the eye <NUM>). Generally the returning portion of the sample beam <NUM> is relatively low and variable. In contrast, there is little light loss in the reference path <NUM>. Therefore, to maximize light delivered into the eye <NUM> and to balance the returning light from both the sample and reference paths, the pickoff/combiner assembly <NUM> transmits more light than it reflects. Additionally, there is a further safety requirement to limit the amount of light entering the eye <NUM>. Accordingly, as an example, for an OCT source beam <NUM> having about 6mW of light and the above considerations, an <NUM>% reflectivity can be selected as a suitable reflectivity level. The <NUM>% reflectivity results in a pickoff percentage of <NUM>% for the reference beam <NUM> and <NUM>% for the sample beam <NUM> or a ratio of <NUM> to <NUM> sample to reference. A ratio around <NUM> to <NUM> may also be suitable. The reflectivity for the two polarizations match with respect to each other to within approximately <NUM>%, [(<NUM>-<NUM>)/<NUM> = <NUM>%].

Each of the other surfaces <NUM>, <NUM>, <NUM> has an anti-reflection or AR coating. The low angle of incidence on these surfaces also assures polarization insensitivity. Because of the high refractive index of the glass used in the illustrated embodiment, a simple protected magnesium fluoride MgF<NUM> coating can be used resulting in a low reflectivity of < <NUM>% per surface. The simple MgF<NUM> coating has the advantages of consistent control in fabrication and low probability of coating degradation.

Using high refractive index glass for the first and second optical wedges <NUM>, <NUM> provides advantages over low refractive index glass such as: high reflectivity (Fresnel reflection) for the uncoated surface at low angle of incidence, a higher refractive angle for the same angle of incidence thereby providing separation of the beams, and a simple MgF<NUM> coating provides excellent anti-reflection i.e. lower reflectivity. A disadvantage of using high refractive index glass for the first and second optical wedges <NUM>, <NUM> is the higher dispersion usually associated with the higher refractive index. The higher dispersion, however, is offset by the offsetting wedge geometry.

Variations in the configuration of the pickoff/detection assembly <NUM> are possible. For example, the pickoff/detection assembly <NUM> might be configured as a single element depending on the bandwidth/wavelengths of the OCT source beam <NUM> and other relevant mechanical considerations. The single element may be a plate beam splitter, a wedged plate, a cube, or other known beam splitting element. The wedge angle <NUM> of the second optical wedge <NUM> can be different from the wedge angle <NUM> of the first optical wedge <NUM>. The second optical wedge <NUM> can also be made from a different glass from the first optical wedge <NUM>. Beam dumps and baffles (not illustrated) can also be used for unused light reflected from the surfaces <NUM>, <NUM>, <NUM>, <NUM>.

Referring back to <FIG>, <FIG>, and <FIG>, after exiting the pickoff/detection assembly <NUM>, the sample beam <NUM> is reflected by mirrors <NUM>, <NUM> and then passes through an aperture <NUM> before being incident on the beam combiner <NUM>. The sample beam <NUM> is transmitted through the beam combiner <NUM> and is then reflected by a mirror <NUM> so as to be incident on the beam combiner <NUM>. The sample beam <NUM> is transmitted through the beam combiner <NUM> into the shared optics <NUM>. Beam aperture <NUM> may be used to limit the amount of light delivered to the eye. This limit may be set by optical hazard considerations and limits, for example, as set by international standards. The beam aperture <NUM> in the reference arm <NUM> may be used to fine tune the balance of light in the combined reference and sample arms. The beam aperture <NUM> can also be used to limit the amount of light directed into the OCT detector <NUM> to prevent detector saturation, for example. The aperture <NUM> may also be used to match reference beam size and numerical aperture to that of the sample.

The mirrors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> in the ranging subsystem <NUM> can be metal (e.g., silver) coated if possible to reduce and prevent adverse dispersion effects. Alternatively, transmission within the ranging subsystem <NUM> can be through complex dielectrics where suitable as opposed to reflecting to reduce and prevent adverse dispersion effects.

The alignment guidance subsystem <NUM> includes the aim beam light source <NUM> and the aim path <NUM>. The aim path <NUM> transmits the aim beam <NUM> emitted by the aim beam light source <NUM> to the beam combiner <NUM>. After being emitted by the aim beam light source <NUM>, the aim beam <NUM> is reflected by mirrors <NUM>, <NUM> and then passes through a coupling lens <NUM> into an optical fiber <NUM>. The aim beam <NUM> emerges from the optical fiber <NUM> so as to pass through a collimating lens <NUM>, then through an aperture <NUM>, and then through a beam expander <NUM>. The beam expander <NUM> propagates the aim beam <NUM> over a distance while accommodating positional and/or directional variability of the aim beam <NUM>, thereby providing increased tolerance for component variation. The beam expander <NUM> relays an image of the aperture <NUM> to a plane near the galvo mirrors <NUM> and <NUM>. This plane is an alignment reference plane for the system. After the beam expander <NUM>, the aim beam <NUM> is reflected by mirrors <NUM>, <NUM>, <NUM> so as to be incident on the beam combiner <NUM>, which reflects the aim beam <NUM> toward the mirror <NUM>. The aim beam <NUM> is reflected by the mirror <NUM> so at to be incident on the beam combiner <NUM>. The aim beam <NUM> passes through the beam combiner <NUM> and continues into the shared optics <NUM>.

In many embodiments, the aim beam <NUM> can be used as a system alignment aid. By checking/ensuring suitable system alignment on a suitable reoccurring time frame, patient safety may be enhanced. The aim beam <NUM> can also be used as a targeting aid for directing the laser pulse beam <NUM> at target locations in the eye <NUM>. The aim beam <NUM> can also be used as a fixation light source to give the patient something to look at to control orientation of the eye <NUM>. The aim beam <NUM> can also be used for monitoring the angle and position of the X, Y, & Z actuators. This could be accomplished by placing a detector or detectors such as position sensing detectors in the beam or a pickoff of the beam. A pickoff location may be the reflections off of beam combiner <NUM>. In many embodiments, the aim beam light source <NUM> includes a diode laser that is directly controlled via electrical input with no attenuation required.

The shared optics <NUM> provides a common optical path for the laser pulse beam <NUM>, the sample beam <NUM>, and the aim beam <NUM>. The shared optics <NUM> includes the beam combiner <NUM>, the beam combiner <NUM>, the Z-telescope <NUM>, the X-scan device <NUM>, the Y-scan device <NUM>, the beam combiner <NUM>, and the objective lens assembly <NUM>. The shared optics <NUM> also includes periscopes <NUM>, <NUM>, which provide an adjustable means to align the laser pulse beam <NUM>, the sample beam <NUM>, and the aim beam <NUM> with the downstream optical path through the downstream portion of the shared optics <NUM>, the patient interface <NUM>, and into the eye <NUM>.

In many embodiments, the shared optics <NUM> is configured to distribute aberration correction balance amongst the Z-telescope <NUM>, the objective lens assembly <NUM>, and the patient interface lens <NUM>. Specifically, in many embodiments, the Z-telescope <NUM>, the objective lens assembly <NUM>, and the patient interface lens <NUM> are configured such that the total aberration contribution of all the optical elements in the Z-telescope <NUM>, the objective lens assembly <NUM>, and the patient interface lens <NUM> sums to zero as nearly as practicable.

The alignment guidance subsystem <NUM> further includes the video subsystem <NUM>. The video subsystem <NUM> includes the camera <NUM>, the illumination light source <NUM>, and the beam combiner <NUM>.

The video subsystem <NUM> can be designed for one or more modes of operation. For example, the video subsystem <NUM> can be designed to provide approach guidance during docking of the eye <NUM> to the laser eye surgery system <NUM>. The docking approach guidance mode of operation can utilize dark-field cross-polarized illumination. The docking approach guidance mode of operation can utilize bright field fixation. Once the eye <NUM> is docked to the laser eye surgery system <NUM>, the video subsystem <NUM> can provide a dark-field cross polarization image of the incised region of the eye <NUM> and the patient interface <NUM>. Once the eye is docked to the laser eye surgery system <NUM>, the video subsystem <NUM> can provide bright-field illumination for automated iris detection.

<FIG> illustrates transmission and reflectivity characteristics of the beam combiner <NUM> used to combine the aim beam <NUM> and the OCT sample beam <NUM>, the beam combiner <NUM> used to combine the laser pulse beam <NUM> with both the aim beam <NUM> and the OCT sample beam <NUM>, and the beam combiner <NUM> used to reflect an image to the video subsystem <NUM>. The beam combiner <NUM> is configured to transmit the OCT sample beam <NUM> and reflect the aim beam <NUM>. For example, the beam combiner <NUM> can be configured to transmit wavelengths from <NUM> to <NUM> (both s and p polarizations) and reflect wavelengths from <NUM> to <NUM>. The beam combiner <NUM> is configured to reflect the laser pulse beam <NUM> while transmitting both the OCT sample beam <NUM> and the aim beam <NUM>. For example, the beam combiner <NUM> can be configured to reflect wavelengths from <NUM> to <NUM> (including linear polarization) and transmit wavelengths from both <NUM> to <NUM> and <NUM> to <NUM>. The beam combiner <NUM> is configured to transmit each of the OCT sample beam <NUM> and the laser pulse beam <NUM>, partially reflect the aim beam <NUM>, and reflect illumination light from the illumination light source (e.g., near infrared LED illumination - wavelengths from <NUM> to <NUM>).

<FIG> illustrates the use of the Z-telescope <NUM> to focus the laser pulse beam <NUM> to different depths within the eye <NUM>. In the illustrated embodiment, the Z-telescope <NUM> includes a lens <NUM> and a lens <NUM>. The distance (UF ZL) between the lenses <NUM>, <NUM> determines the depth in the eye <NUM> at which the laser pulse beam <NUM> is focused. The distance (UF ZL) determines whether the laser pulse beam <NUM> is diverging (becoming wider) as the laser pulse beam <NUM> travels between the lens <NUM> and the X-scan device <NUM>, is converging (becoming narrower) as the laser pulse beam <NUM> travels between the lens <NUM> and the X-scan device <NUM>, or is neither diverging or converging (constant width) as the laser pulse beam <NUM> travels between the lens <NUM> and the X-scan device <NUM>. The more the laser pulse beam <NUM> is diverging between the lens <NUM> and the X-scan device <NUM>, the deeper the depth in the eye <NUM> at which the laser pulse beam <NUM> is focused. The more the laser pulse beam <NUM> is converging between the lens <NUM> and the X-scan device <NUM>, the shallower the depth in the eye <NUM> at which the laser pulse beam <NUM> is focused. Table <NUM> provides example values for the distance (UF ZL) between the lenses <NUM>, <NUM>, as well as corresponding values of the depth of the focal point (UF Z), corresponding values of the resulting numerical aperture (NA), corresponding values of the diameter of the laser pulse beam <NUM> at the lens <NUM>, and corresponding values of the diameter of the laser pulse beam <NUM> at the X-scan device <NUM>.

In many embodiments, the laser eye surgery system <NUM> is configured to be capable of delivering laser pulses to tightly focused points to disrupt and thereby incise tissue throughout a desired treatment volume within the eye <NUM>. For example, <FIG> is a diagram illustrating a predicted treatment volume <NUM> (hatched area) within which the laser eye surgery system <NUM> is capable of incising tissue. The predicted treatment volume <NUM> is bounded in the transverse directions by an x-direction boundary <NUM> and a y-direction boundary <NUM>. Boundary conditions are determined by optical model simulation of threshold levels taking into account numerical aperture, aberration control, beam quality of the laser, polarization of the laser, pulse width, and optical train transmission anchored to empirically determined levels of tissue breakdown. To ensure that there is cutting, the boundaries factor in a margin above this threshold. A <NUM> times or <NUM> times margin above an empirically determined threshold is reasonable given the range of variation that goes into determining threshold levels. The predicted treatment volume <NUM> is wider in the x direction for z values (axial distance from the posterior surface of the patient interface lens <NUM>) of less than about <NUM> and is wider in the y direction for z values of greater than about <NUM>. As shown, the predicted treatment volume <NUM> encompasses the cornea <NUM> and lens capsule <NUM> of the eye <NUM>, thereby enabling the creation of incisions at any desired location in the cornea <NUM> and lens capsule <NUM>.

As discussed above, patients with floating opaque bodies in the vitreous may experience degradation of sight. The vitreous bodies may appear in the field of vision for a patient and cause them blurry sight, black spots, or moving images that distract their normal sight. The systems and methods described herein may be used to dissect the vitreous bodies and/or liquefy such bodies within the vitreous humor. The laser systems here may make clean cuts in the vitreous humor to deal with these floaters without causing damage to the retina. These femtosecond laser pulses can treat the vitreous much closer to retina than existing nanosecond/ sub-nanosecond IR systems, which helps address the worst floaters with close proximity. Safer direct destruction of opaque floaters may also be possible due to lower femtosecond pulse energy levels.

By doing so, the vitreous bodies may be moved, broken up, or removed in order to resolve the sight degradation. The most disturbing floaters are in the direct line of sight of the fovea. Moving them out of the central zone of vision will give the patient a significant reduction of symptoms. In certain example embodiments, the vision may be corrected without physically cutting into the surface of the eye and/or opening the eye.

In certain example embodiments, and in accordance with the invention, the vitreous bodies may be cut around in three dimensions in order to aid the physical extraction from the eye. A femtosecond laser may be used for creation of cut planes and patterns in vitreous. Various shapes are cut to ease the removal of the vitreous body and vitreous humor from the eye. In certain example embodiments, the cutting plane of the laser within the vitreous humor may include cutting from the bottom up (posterior to anterior) so the laser beam does not have to go through any bubbles that may form in the vitreous humor. Various cutting patters may be used such as cylinder, a square prism, a rectangular prism, an ellipse, a trapezoid, a pyramid, or other shape. Any of various shapes may be cut in the vitreous humor. Cylindrical shapes may be successfully cut in the vitreous and effectively liquefy or dissect vitreous bodies within. One goal of such a cylinder may be the isolation of the body to be removed in the interior of the eye by a cutting plane.

In certain example embodiments, an external adapter, such as a contact lens on the patient eye, may allow the laser to cut the appropriate planes in the vitreous humor. Such lenses may provide for limited depth of focus in the vitreous cavity. This protects the retina from laser energy being projected too deeply into the eye, and limits the depth of focus to a safe distance to break up or liquefy the vitreous body but stay away from the retina.

As the depth of the eye from cornea surface to retina surface is about <NUM>, the place of action of the laser in certain examples here may be between <NUM> and <NUM>, such as for example, <NUM> from the retina or <NUM> from the retina. Such a distance from the retina may allow for the system to utilize laser energy powers of up to <NUM>µJ to be used. In certain example embodiments, the power does not exceed <NUM>µJ.

<FIG> shows an example of the systems here, treating a vitreous body in the vitreous humor of an eye. In <FIG>, the eye <NUM> is shown being treated by the laser system <NUM>. The laser system <NUM> is shown projecting a laser beam <NUM> into the anterior chamber vitreous humor <NUM> of the eye <NUM>. The laser beam <NUM> is shown passing through a contact lens <NUM> placed on the eye <NUM>. This contact lens determines the depth of focus that the laser beam <NUM> can reach, thereby safety limiting the laser <NUM> from hitting and/or damaging the retina <NUM>.

The vitreous bodies <NUM> which are bothering the patient in this example may be located anywhere within the posterior chamber vitreous humor <NUM>.

<FIG> shows the eye <NUM> the laser system <NUM> and the contact lens <NUM>. It also shows an example of the laser <NUM> cutting a cylindrical shape <NUM> through and around the vitreous bodies <NUM> and within the anterior chamber vitreous humor <NUM>. This cutting plane <NUM> may be used to liquefy or dissect the vitreous bodies <NUM>.

The present inventive system enables surgical techniques that include utilizing a pulsed <NUM> to <NUM> laser to perform highly precise physical modifications of ocular targets, including tissues within the vitreous chamber (such as vitreous humors, etc.). This can be done in two different operating regimes: with or without cavitation bubble formation. The sub-cavitation regime can also be used to modify the refractive index of ocular targets.

The threshold pulse energy may be Eth=Φ*d<NUM>/<NUM>, where Φ is the threshold radiant exposure and d is the focal spot diameter. Here, the focal spot diameter, d, is d=λF/Db where λ is the wavelength, F is the focal length of the last focusing element and Db is the beam diameter of the last lens. For stable and reproducible operation, pulse energy should exceed the threshold by at least a factor of <NUM>, however, the energy level can be adjusted to avoid damage to the corneal endothelium.

The incident light of the laser used for the modification of the eye tissue generally has a wavelength of between <NUM> and <NUM>, preferably between <NUM> and <NUM>. In many embodiments, the laser light has a wavelength of <NUM>.

The pulse energy of laser pulses is generally between. <NUM>µJ and <NUM>µJ. In many embodiments, the pulse energy will be between <NUM>µJ and <NUM>µJ, or more precisely, between <NUM>µJ and <NUM>µJ.

A pulse repetition rate of the laser pulses is generally between <NUM> and <NUM>. In many embodiments, the pulse repetition rate is between <NUM> to <NUM>, or between <NUM> to <NUM>.

Spot sizes of the laser pulses are generally smaller than <NUM>. In many embodiments, the spot size is preferably smaller than <NUM>, typically <NUM> to <NUM>.

A pulse duration of the laser pulses is generally between 1ps and <NUM> ns. In many embodiments, the pulse duration is between <NUM> ps to <NUM> fs , or between. <NUM> ps and <NUM> fs.

In some embodiments, the beam quality, also referred to as M<NUM> factor, is between <NUM> and <NUM>. The M<NUM> factor is a common measure of the beam quality of a laser beam. In brief, the M<NUM> factor is defined as the ratio of a beam's actual divergence to the divergence of an ideal, diffraction limited, Gaussian TEM<NUM> beam having the same waist size and location as is described in ISO Standard <NUM>.

A peak power density, obtained by dividing the peak power of the laser pulse by the focal spot size, is generally expressed in units of GW/cm<NUM>. In general, the peak power density of the laser pulses should be sufficiently high to modify the ocular tissue to be treated. As would be understood by those ordinarily skilled, the peak power density depends upon a number of factors, including the wavelength of the selected laser pulses. In some embodiments, a peak power density is generally in the range of. <NUM> GW/cm<NUM> to <NUM> GW/cm<NUM> will be used to cut ocular tissue.

The scan range of the laser surgical system is preferably in the range of <NUM> to <NUM>.

In many embodiments for the modification of ocular tissue, spot spacing between adjacent laser pulses is typically in the range of about <NUM> to <NUM>, preferably <NUM> to <NUM>.

A numerical aperture should be selected that preferably provides for the focal spot of the laser beam to be scanned over a scan range of <NUM> to <NUM> in a direction lateral to a Z-axis that is aligned with the laser beam. The NA of the system should be less than <NUM>, preferably less than <NUM> and more preferably in a range of <NUM> to <NUM>, typically between <NUM> and <NUM>. In some specific embodiments, the NA is <NUM>. For each selected NA, there are suitable ranges of pulse energy and beam quality (measured as an M<NUM> value) necessary to achieve a peak power density in the range required to cut the ocular tissue. Further considerations when choosing the NA include available laser power and pulse rate, and the time needed to make a cut. Further, in selection of an appropriate NA, it is preferable to ensure that there is a safe incidental exposure of the iris, and other ocular tissues, that are not targeted for cuts.

As described, the systems and methods here may use a femtosecond laser to cut various planes in the vitreous humor of the eye for treatment of floaters or other treatments. This is different than cutting the cornea or the lens, as the laser must reach deeper into the eye, beyond the anterior chamber of the eye to make such cuts. Certain embodiments may be used to cut examples such as but not limited to:.

These parameters of cutting planes may be varied by the system or a user of the system in order to cut different planes. The higher the NA, the more strongly the light is focused. Thus, as an NA of <NUM> may be used to cut the lens of an eye, an NA of <NUM> may be used to cut in the vitreous humor.

In certain example embodiments, a z actuator may be used in the system to change the focal length of the laser beam in the z axis. Such a z actuator may also be used to focus the laser beam in the correct portion of the eye, the vitreous humor, and operate on the vitreous bodies found there. Certain example embodiments may employ an adapter which may be affixed to a laser cataract system in order to move the focal length of the laser so as to reach into the anterior chamber instead of operate on the lens. Such an adapter may include a z stager as described herein. Other possible features of such an adapter may be a numerical aperture feature.

In certain example embodiments, the systems here using OCT may utilize imaging of various parts of the eye in order to locate structures in the eye to either avoid or operate on. In certain examples, the optical field cone between the lens and the retina is the area of concern to clear out or remove vitreous body floaters. This area of concern is bounded by the eye's lens and the retina, which may be located, measured, modeled and/or otherwise recorded before operation within the vitreous humor is conducted. For example, the system may be used to find the location of the posterior of the lens and the retina, so as to be able to safely operate between these two structures, in the interior chamber, at a safe distance. Sub-one millimeter from the retina, for example, may be a safety boundary that the laser could operate.

In certain examples, the vitreous body floaters may be identified by the patient, and the systems described herein may use that information to narrow in on their location. This may require a translation of a raw directional or positional location from the patient, to a location coordinate in three dimensions for the systems here. This translation may take into account any movement or orientation of the patient before and during treatment.

Certain example embodiments may use OCT to determine the refractive index for a particular patient's eye. Instead of using a guesstimate or approximation of the refractive index of average human eyes, the systems here may be used to accurately measure the refractive index of the particular patient's eye and thereby more carefully locate the vitreous bodies for operation. Deep in the vitreous, toward the posterior, chromatic aberration will focus the treatment beam further behind the intended focus. The anterior offset may be used to position the optical breakdown in the same plane as the aiming beam focus. Manual defocus of the system may be used or automated defocus may be used. Other uses of this invention may also include the combination of Vitrectomy to pre-lyse the vitreous tissue.

<FIG> is a graph showing the single pulse Maximum Pulse Energy (MPE, in milliJoules) calculated according ANSI-Z136. <NUM> as a function of focal distance of the light source from the retina (in mm). The MPE is calculated for NA values of <NUM> (upper curve) and <NUM> (lower curve). Since the single pulse energy of the light source may typically be in the <NUM> to <NUM> microJoule range, the present invention contemplates procedures whose scan patterns require focal lengths from the retina that are, in some embodiments, less than <NUM> from the retina, and in many embodiments, less than <NUM> from the retina. Of course, closer scans to the retina may require reductions in pulse energy to comply with ANSI-Z136. <NUM> compliant MPEs. This is very different from the use of ns-laser pulses which require multiple mJ of pulse energy to induce breakdown in the posterior chamber. At minimum <NUM>-2mJ are used which would require a <NUM>-<NUM> safety distance for the <NUM>. 14NA example and a <NUM>-<NUM> safety distance for the <NUM>. 1NA example. Note that most visual impairing floaters are in close proximity of the retina. The closer the floaters the more visually impaired the patients are which excludes the use of ns-Lasers.

As disclosed herein, features consistent with the present inventions may be implemented via computer-hardware, software and/or firmware. For example, the systems disclosed herein may be embodied in various forms including, for example, a data processor, such as a computer that also includes a database, digital electronic circuitry, firmware, software, computer networks, servers, or in combinations of them. Further, while some of the disclosed implementations describe specific hardware components, systems consistent with the innovations herein may be implemented with any combination of hardware, software and/or firmware. Moreover, the above-noted features and other aspects and principles of the innovations herein may be implemented in various environments. Such environments and related applications may be specially constructed for performing the various routines, processes and/or operations or they may include a general-purpose computer or computing platform selectively activated or reconfigured by code to provide the necessary functionality. The processes disclosed herein are not inherently related to any particular computer, network, architecture, environment, or other apparatus, and may be implemented by a suitable combination of hardware, software, and/or firmware. For example, various general-purpose machines may be used with programs written in accordance with teachings of the invention, or it may be more convenient to construct a specialized apparatus or system to perform the required methods and techniques.

Aspects of the system described herein, such as the logic, may be implemented as functionality programmed into any of a variety of circuitry, including programmable logic devices ("PLDs"), such as field programmable gate arrays ("FPGAs"), programmable array logic ("PAL") devices, electrically programmable logic and memory devices and standard cell-based devices, as well as application specific integrated circuits. Some other possibilities for implementing aspects include: memory devices, microcontrollers with memory (such as EEPROM), embedded microprocessors, firmware, software, etc. Furthermore, aspects may be embodied in microprocessors having software-based circuit emulation, discrete logic (sequential and combinatorial), custom devices, fuzzy (neural) logic, quantum devices, and hybrids of any of the above device types. The underlying device technologies may be provided in a variety of component types, e.g., metal-oxide semiconductor field-effect transistor ("MOSFET") technologies like complementary metal-oxide semiconductor ("CMOS"), bipolar technologies like emitter-coupled logic ("ECL"), polymer technologies (e.g., silicon-conjugated polymer and metal-conjugated polymer-metal structures), mixed analog and digital, and so on.

It should also be noted that the various logic and/or functions disclosed herein may be enabled using any number of combinations of hardware, firmware, and/or as data and/or instructions embodied in various machine-readable or computer-readable media, in terms of their behavioral, register transfer, logic component, and/or other characteristics. Computer-readable media in which such formatted data and/or instructions may be embodied include, but are not limited to, non-volatile storage media in various forms (e.g., optical, magnetic or semiconductor storage media) and carrier waves that may be used to transfer such formatted data and/or instructions through wireless, optical, or wired signaling media or any combination thereof. Examples of transfers of such formatted data and/or instructions by carrier waves include, but are not limited to, transfers (uploads, downloads, e-mail, etc.) over the Internet and/or other computer networks via one or more data transfer protocols (e.g., HTTP, FTP, SMTP, and so on).

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise," "comprising," and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in a sense of "including, but not limited to. " Words using the singular or plural number also include the plural or singular number respectively. Additionally, the words "herein," "hereunder," "above," "below," and words of similar import refer to this application as a whole and not to any particular portions of this application. When the word "or" is used in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list.

Although certain presently preferred implementations of the invention have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various implementations shown and described herein may be made without departing from the scope of the invention as defined by the claims. Accordingly, it is intended that the invention defined by the claims be limited only to the extent required by the applicable rules of law.

Claim 1:
A laser surgical system for making incisions in ocular tissues, the system comprising:
a laser system comprising a scanning assembly, a laser operable to generate a laser beam configured to incise ocular tissue; and
a control system operably coupled to the laser system and configured to:
operate the imaging device to locate a posterior of a lens in an eye;
operate the imaging device to locate a retina in the eye;
operate the imaging device to locate a vitreous body in a vitreous humor in the eye;
process the image data to determine a treatment scanning pattern for scanning a focal zone of the laser beam for performing one or more incisions in the vitreous humor, wherein the treatment scanning pattern includes cutting planes that form a three-dimensional shape around the vitreous body; and
wherein positioning of the focal zone is guided by the control system based on the location of the vitreous body so as to perform the one or more incisions in the vitreous humor; wherein the laser is configured to incise the vitreous humor in the eye with the treatment scanning pattern.