Systems and methods for dissecting tissue - Patents.com

Abstract

A system for dissecting tissue with plasma includes an elongated electrode configured to dissect tissue along a tissue dissection profile, and a tissue contacting element configured to shape the tissue with one or more channels or protrusions to form one or more corresponding protrusions or depressions in the tissue surface while the tissue is dissected with the electrode along the dissection profile. The tissue contacting element shapes the tissue sufficiently to allow the tissue to form one or more complementary features along the dissection profile when the tissue relaxes to a freestanding configuration upon removal of the tissue contacting element. The complementary features may be dissected into the tissue and provide increased mechanical stability between separated tissue regions, such as with nominally interlocking protrusions and depressions.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 63 / 193,977, filed May 27, 2021, the entire disclosure of which is incorporated herein by reference.

[0002] The subject matter of this application is related to PCT / US2020 / 070757, filed November 6, 2020, entitled "Systems and methods for incising tissue," and published on May 14, 2021 as WO2021092628, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0003] Tissue ablation and dissection can be used in many ways to perform procedures, such as surgical procedures. For example, lasers can be used to correct refractive errors, such as myopia, remove cataracts, and treat glaucoma and retinal diseases. Tissue ablation and dissection can also be used in orthopedics and cardiology, for example, to perform surgical procedures.

[0004] Research related to the present disclosure suggests that the effectiveness and availability of surgical procedures may, at least in some cases, be related to the limitations of the devices used to incise and ablate tissue. For example, lasers such as femtosecond lasers may be complex and treatments may take longer than would be ideal. Also, the tissue removal profile along the laser-induced incision may not be as smooth as would be ideal, at least in some cases. Also, in laser treatments, tissue remnants and debris, such as plumes associated with laser irradiation, may affect the accuracy and effectiveness of ablation and incision.

[0005] Mechanical cutting with a blade, such as a microkeratome blade, may be used for some surgical procedures, but research related to the present disclosure suggests that mechanical cutting with a blade may, at least in some cases, be less precise than would be ideal and produce a rougher surface. Mechanical keratomes have been used to generate corneal flaps for surgical procedures such as LASIK, but research related to the present disclosure suggests that mechanical keratomes may take somewhat longer than would be ideal, and the resulting flap may, at least in some cases, be somewhat irregular and rougher than would be ideal. A scalpel or diamond knife may be used to manually cut two separate flaps into tissues such as sclera and / or corneal tissue in traditional canaloplasty, but this is technique-dependent and may be somewhat difficult for at least some practitioners, which may result in associated postoperative complications. It would be useful to reduce technique-dependence and postoperative complications.

[0006] Femtosecond lasers have been used to generate corneal flaps and pockets, but research related to this disclosure suggests that the time to form the flaps and pockets may take longer than would be ideal, at least in some cases. The Small Incision Corneal Leaf Extraction (SMILE) procedure is a more recent approach to reshape the cornea that utilizes a femtosecond laser system to ablate tissue along the border of a three-dimensional corneal leaflet in the corneal stroma, which can be removed through a corneal opening. However, research related to this disclosure suggests that the three-dimensional corneal leaflet formed and removed using this procedure may, at least in some cases, be shaped sub-ideally and may contain a "tissue bridge" that must be cut from the leaflet before it can be extracted. This additional step of separating the bridge between the leaflet and the corneal stroma is known to be traumatic and present additional risks to the patient. The amount of time to ablate the tissue that defines the leaflet and opening may also be somewhat longer than would be ideal.

[0007] Electrodes have been proposed for treating tissue, but previous approaches may result in more tissue damage and less precise incisions than would be ideal. Electrodes that generate plasma have been proposed, but these previous approaches may not be well suited for cutting large amounts of tissue, and the accuracy may be sub-ideal, at least in some cases.

[0008] Conventional nominally planar incisions, such as those produced by microkeratomes, may allow dehiscence and cellular infiltration into the wound and therefore require additional postoperative medical procedures and / or monitoring that would not otherwise be required. It may be beneficial to provide improved adhesion of the flap to the underlying foundation, reducing dehiscence and / or eliminating cellular infiltration.

[0009] In light of the above, there exists a need for an improved approach for treating tissue using incisions that ameliorates at least some of the aforementioned limitations. Ideally, such an approach would reduce complications and treatment times and provide more precise incisions with improved outcomes. Summary of the Invention [Means for solving the problem]

[0010] The embodiments of the present disclosure provide improved methods and systems for dissecting tissue with improved stability of the tissue between the sides of the dissection. In some embodiments, a system for dissecting tissue with plasma comprises an elongated electrode configured to dissect the tissue along a tissue dissection profile and a tissue contacting element configured to shape the tissue. The tissue contacting element comprises one or more channels or protrusions to form one or more corresponding protrusions or indentations in the tissue surface while the tissue is dissected with the electrode along the dissection profile. The tissue contacting element shapes the tissue sufficiently to allow the tissue to form one or more complementary features along the dissection profile as the tissue relaxes to a freestanding configuration upon removal of the tissue contacting element. The complementary features may be dissected into the tissue to provide increased mechanical stability between separated tissue regions, such as with nominally interlocking protrusions and indentations.

[0011] In some embodiments, the elongated electrode is configured to flex, generate plasma, and incise tissue. An electrical energy source can be operably coupled to the electrode and configured to provide electrical energy to the electrode and generate plasma. In some embodiments, a tensioning element is operably coupled to the elongated electrode. The tensioning element can be configured to provide tension to the elongated electrode, allowing the elongated electrode to flex in response to the elongated electrode engaging tissue and generating plasma. In some embodiments, the tensioning element operably coupled to the flexible elongated electrode allows for the use of small diameter electrodes, such as 5 μm to 20 μm diameter electrodes, which can allow thin incisions to be made with reduced tissue damage. In some embodiments, the tensioning of the electrode allows the electrode to more precisely incise tissue by reducing variability in the position of the electrode along the incision path.

[0012] In some embodiments, the elongated electrode is operably coupled to one or more components to enable tissue ablation along the path. The elongated electrode can be coupled to a support structure that moves with the electrode and provides the incision along the path. The support structure can be configured to support one or more arms, such as a plurality of arms, that support an electrode suspended between the arms. The support structure, the one or more arms, and the elongated electrode may comprise components of an electrode assembly. The electrode assembly can be operably coupled to a translation element to provide translational movement to the electrode to incise the tissue. In some embodiments, a contact plate is configured to engage the tissue and shape the tissue prior to incision with the elongated electrode, which can provide improved accuracy of incision and shaping of the tissue to be removed.

[0013] In some embodiments, a gap extends between the support structure and the electrodes suspended between the arms, which can provide bidirectional tissue dissection and reduce treatment time. In some embodiments, the gap is sized to receive tissue and dissect the tissue extending into the gap as the support structure and electrodes are retracted proximally. In some embodiments, the support structure and electrodes are advanced into the tissue with a first configuration of one or more contact plates on a first pass, dissecting the tissue with the first dissection, and the support structure and electrodes are retracted proximally with a second configuration of one or more contact plates, dissecting the tissue. In some embodiments, the second configuration is different from the first configuration, and the tissue dissected with the first pass extends into the gap and dissected with the second pass to provide an excised volume of tissue for subsequent removal. In some embodiments, the ablated volume of tissue comprises a thickness profile corresponding to the difference between a first profile of a first configuration and a second profile of a second configuration of the one or more contact plates. In some embodiments, a corneal strip corresponding to a refractive correction of the eye is cut with the first and second passes, and the corneal strip can be subsequently removed to provide the refractive correction.

[0014] In some embodiments, the elongated electrode is configured to dissect tissue, such as corneal tissue. A source of electrical energy is operably coupled to the elongated electrode and configured to provide electrical energy to the electrode. A contact plate is configured to engage a portion of tissue, such as the cornea, and shape the tissue prior to dissecting the cornea with the electrode. A support structure can be operably coupled to the elongated electrode and the plate, the support structure configured to move the electrode relative to the plate and dissect the corneal tissue with the electrode.

[0015] In some embodiments, the contact plate is configured to provide complementary features on a first surface and a second surface of an incision in tissue, such as corneal tissue. The first surface and the second surface may be the result of a single incision. Such complementary features may be configured to form nominally interlocking protrusions and depressions on such first and second surfaces of tissue, which may be incised and deformed using contact elements and / or suction elements prior to and / or during incision, and may be equally referred to as "complementary features," "interlocking features," and "mating features," or any combination thereof. The protrusions may be configured to mate with the depressions, or vice versa. Similarly, the protrusions may be made on the first surface and / or the second surface, and the mating depressions made on the second surface and / or the first surface.

[0016] In some embodiments, the suction element is configured to provide complementary features of the first and second surfaces of an incision in tissue, such as corneal tissue, and may be part of a flap or pocket.

[0017] In some embodiments, suction elements and contact elements may be used to create complementary features.

[0018] (Incorporated by reference) All patents, applications, and publications referenced and identified herein are incorporated by reference in their entirety and shall be considered incorporated by reference in their entirety even if referenced elsewhere in this application. In particular, International Patent Application No. PCT / US2020 / 070757, filed November 6, 2020, entitled "SYSTEMS AND METHODS FOR INCISING TISSUE," and U.S. Patent Application No. 63 / 193,977, filed May 27, 2021, entitled "SYSTEMS AND METHODS FOR INCISING TISSUE," are identified herein. [Brief description of the drawings]

[0019] A better understanding of the features, advantages, and principles of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments and the accompanying drawings, listed below.

[0020] [Figure 1A] FIG. 1A is directed to a schematic image of an eye shown in cross-section and indicating anatomical locations therein, according to an embodiment of the present disclosure.

[0021] [Figure 1B] FIG. 1B is directed to a plot showing the relationship between measured threshold discharge voltage and pulse duration for negative and positive voltages for a single long, thin electrode, according to an embodiment of the present disclosure.

[0022] [Figure 2A] 2A-2F depict examples of different conditions encountered with varying electrode / tissue spacing and / or electrode voltage, according to embodiments of the present disclosure. [Figure 2B] 2A-2F depict examples of different conditions encountered with varying electrode / tissue spacing and / or electrode voltage, according to embodiments of the present disclosure. [Figure 2C]2A-2F depict examples of different conditions encountered with varying electrode / tissue spacing and / or electrode voltage, according to embodiments of the present disclosure. [Figure 2D] 2A-2F depict examples of different conditions encountered with varying electrode / tissue spacing and / or electrode voltage, according to embodiments of the present disclosure. [Figure 2E] 2A-2F depict examples of different conditions encountered with varying electrode / tissue spacing and / or electrode voltage, according to embodiments of the present disclosure. [Figure 2F] 2A-2F depict examples of different conditions encountered with varying electrode / tissue spacing and / or electrode voltage, according to embodiments of the present disclosure.

[0023] [Diagram 3] FIG. 3 is directed to plots showing the relationship between measured negative threshold voltage and electrode diameter for fixed pulses of varying duration, in accordance with an embodiment of the present disclosure.

[0024] [Figure 4] 4 and 5 are directed to an electrode subsystem of a system for dissecting a target tissue structure, according to an embodiment of the present disclosure. [Diagram 5] 4 and 5 are directed to an electrode subsystem of a system for dissecting a target tissue structure, according to an embodiment of the present disclosure.

[0025] [Figure 6] FIG. 6 is directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure.

[0026] [Figure 7] FIG. 7 depicts a flowchart illustrating steps for practicing a method according to an embodiment of the present disclosure.

[0027] [Figure 8A]8A-8D are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure. [Figure 8B] 8A-8D are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure. [Figure 8C] 8A-8D are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure. [Figure 8D] 8A-8D are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure.

[0028] [Figure 9] FIG. 9 depicts a flowchart illustrating steps of a method according to an embodiment of the present disclosure.

[0029] [Figure 10A] 10A-10F are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure. [Figure 10B] 10A-10F are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure. [Figure 10C] 10A-10F are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure. [Figure 10D] 10A-10F are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure. [Figure 10E] 10A-10F are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure. [Figure 10F] 10A-10F are directed to a system for dissecting a target tissue structure, according to an embodiment of the present disclosure.

[0030] [Figure 11A] 11A and 11B are directed to a segmentally adjustable contact element according to an embodiment of the present disclosure. [Figure 11B]11A and 11B are directed to a segmentally adjustable contact element according to an embodiment of the present disclosure.

[0031] [Figure 12A] 12A and 12B are directed to a disc-shaped corneal strip, according to an embodiment of the present disclosure. [Figure 12B] 12A and 12B are directed to a disc-shaped corneal strip, according to an embodiment of the present disclosure.

[0032] [Figure 13] 13-15 are directed to different corneal strip configurations according to embodiments of the present disclosure. [Figure 14] 13-15 are directed to different corneal strip configurations according to embodiments of the present disclosure. [Figure 15] 13-15 are directed to different corneal strip configurations according to embodiments of the present disclosure.

[0033] [Figure 16A] 16A and 16B are directed to histological images of a porcine cornea containing an incision made according to an embodiment of the present disclosure. [Figure 16B] 16A and 16B are directed to histological images of a porcine cornea containing an incision made according to an embodiment of the present disclosure.

[0034] [Figure 17] FIG. 17 is directed to a plot showing an exemplary electrode voltage versus time, according to an embodiment of the present disclosure.

[0035] [Figure 18] FIG. 18 is directed to a high speed video image of a porcine cornea being dissected, according to an embodiment of the present disclosure.

[0036] [Figure 19A] 19A-19D depict a side view of a tissue "flap" and a side view of a tissue "pocket" according to an embodiment of the present disclosure. [Figure 19B]19A-19D depict a side view of a tissue "flap" and a side view of a tissue "pocket" according to an embodiment of the present disclosure. [Figure 19C] 19A-19D depict a side view of a tissue "flap" and a side view of a tissue "pocket" according to an embodiment of the present disclosure. [Figure 19D] 19A-19D depict a side view of a tissue "flap" and a side view of a tissue "pocket" according to an embodiment of the present disclosure.

[0037] [Figure 20] FIG. 20 depicts a side of a system configured to create a tissue flap or tissue pocket according to an embodiment of the present disclosure.

[0038] [Figure 21] FIG. 21 depicts aspects of a system according to an embodiment of the present disclosure.

[0039] [Figure 22A] 22A-22C depict aspects of a system according to an embodiment of the present disclosure. [Figure 22B] 22A-22C depict aspects of a system according to an embodiment of the present disclosure. [Figure 22C] 22A-22C depict aspects of a system according to an embodiment of the present disclosure.

[0040] [Figure 23] FIG. 23 depicts aspects of a system according to an embodiment of the present disclosure.

[0041] [Figure 24A] 24A and 24B depict a side view of a corneal incision with complementary features according to an embodiment of the present disclosure. [Figure 24B] 24A and 24B depict a side view of a corneal incision with complementary features according to an embodiment of the present disclosure.

[0042] [Diagram 25]FIG. 25 depicts a side view of a corneal incision with complementary features according to an embodiment of the present disclosure.

[0043] [Figure 26] FIG. 26 depicts a side view of a system configured to generate complementary features and an incision comprising complementary features according to an embodiment of the present disclosure.

[0044] [Figure 27A] 27A-27C depict a side view of a suction element of a system configured to generate complementary features according to an embodiment of the present disclosure. [Figure 27B] 27A-27C depict a side view of a suction element of a system configured to generate complementary features according to an embodiment of the present disclosure. [Figure 27C] 27A-27C depict a side view of a suction element of a system configured to generate complementary features according to an embodiment of the present disclosure.

[0045] [Figure 28A] 28A and 28B depict a side view of an aspiration element of a system configured to generate complementary features according to an embodiment of the present disclosure. [Figure 28B] 28A and 28B depict a side view of an aspiration element of a system configured to generate complementary features according to an embodiment of the present disclosure.

[0046] [Figure 29] FIG. 29 depicts a side view of a suction element of a system configured to generate complementary features according to an embodiment of the present disclosure.

[0047] [Diagram 30] FIG. 30 depicts a side view of a system configured to generate complementary features and an incision comprising complementary features according to an embodiment of the present disclosure.

[0048] [Figure 31A]31A-31C depict a side view of an incision with complementary features according to an embodiment of the present disclosure. [Figure 31B] 31A-31C depict a side view of an incision with complementary features according to an embodiment of the present disclosure. [Figure 31C] 31A-31C depict a side view of an incision with complementary features according to an embodiment of the present disclosure.

[0049] [Figure 32A] 32A and 32B depict a side view of a contact element of a system configured to generate complementary features according to an embodiment of the present disclosure. [Figure 32B] 32A and 32B depict a side view of a contact element of a system configured to generate complementary features according to an embodiment of the present disclosure.

[0050] [Diagram 33] FIG. 33 depicts a side of a system including contact elements configured to generate complementary features according to an embodiment of the present disclosure.

[0051] [Diagram 34] FIG. 34 depicts a side of a system including contact elements configured to generate complementary features according to an embodiment of the present disclosure.

[0052] [Diagram 35] FIG. 35 depicts a side of a system including suction elements configured to generate complementary features, according to an embodiment of the present disclosure.

[0053] [Diagram 36] FIG. 36 depicts a side view of an adjustable contact element configured to create complementary features according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Detailed Description The following detailed description provides a deeper understanding of the features and advantages of the invention described in this disclosure, according to the embodiments disclosed herein. Although the detailed description includes many specific embodiments, these are provided by way of example only and should not be construed as limiting the scope of the invention disclosed herein.

[0055] The disclosed systems and methods are highly suitable for incorporation into previous devices and surgical procedures, such as microkeratomes, e.g., SMILE, which incise tissue and create one or more of a flap, pocket, or corneal flap for removal from the tissue. The disclosed methods and systems are highly suitable for lens removal and combination with prosthetic devices, such as removal of the lens nucleus and cortex for placement of an intraocular lens. As a non-limiting example, plasma-induced incisions may be made in the capsule to produce a capsulotomy. Incisions may be made to produce lens fragments or to simplify lens fragmentation and / or lens removal. Incisions may be made in the retina to produce a pocket or flap. In some embodiments, incisions are made in the trabecular meshwork TM to improve drainage and / or reduce intraocular pressure ("IOP"), e.g., for the treatment of glaucoma, or in the iris to produce an iridotomy.

[0056] Although reference is made to incisions in ocular tissue, the disclosed systems and methods are also well suited for making incisions in non-ophthalmic surgical procedures such as orthopedic surgery, cardiovascular surgery, neurosurgery, robotic surgery, pulmonary surgery, urological surgery, and soft tissue surgery. Although reference is made to cutting ocular tissue, the disclosed methods and systems are also well suited for making incisions in one or more of collagen tissue, cartilage, stromal tissue, nervous tissue, vascular tissue, muscle, and soft tissue.

[0057] As a non-limiting example, FIG. 1A illustrates various anatomical locations within the eye that may be suitable for practicing the present disclosure. The eye includes the cornea, sclerocorneal limbus, sclera, capsular bag, lens, retina, iris, and TM. Although not shown, for purposes of clarity, Schlemm's canal may be located adjacent to the TM. The systems of the present disclosure can be used to treat any of these locations. In some embodiments, the cornea is shaped to provide refractive treatment of the eye. In some embodiments, the sclera is incised, e.g., to provide a filtering bleb and treat glaucoma. In some embodiments, at least a portion of the capsule is incised, e.g., to access the cortex and nucleus of the lens. In some embodiments, at least a portion of the lens is incised and removed. In some embodiments, the retina is treated, e.g., with electrodes. In some embodiments, the iris is incised, e.g., with electrodes. In some embodiments, tissue associated with the TM and Schlemm's canal is incised, e.g., with reference to glaucoma surgery. The cornea may have an anterior corneal surface facing the exterior of the eye, which includes corneal epithelial cells supported posteriorly by Bowman's membrane, a posterior corneal surface facing the interior of the eye, which includes corneal endothelium supported anteriorly by Descemet's membrane, and a corneal stroma located between the anterior and posterior corneal surfaces.

[0058] In some embodiments, application of sufficient voltage, including cyclic or pulsatile voltage, to an electrode in or around biological tissue (i.e., a "target tissue structure") may result in the formation of vapor derived from an initial current and / or electric field established by heating at least certain components of the tissue (e.g., water in the tissue) in proximity to the electrode to about the vaporization temperature (or "critical temperature", e.g., 100°C for pure water at standard pressure). The contents of such vapor cavity may then be ionized by the electric field, disrupting (or equivalently "ablating" or "removing") at least a portion of the target tissue structure; particularly if the pulse duration of the pulsatile voltage waveform is sufficiently short compared to the thermal relaxation time of the target tissue structure, thermal containment may be achieved, thereby minimizing the amount of residual damaged tissue produced. The generation of the vapor may be due to a phase change process, and thus the associated temperature increase may cease via a latent heat process once the vaporization temperature is reached. The volume of the vapor cavity (or equivalently, "bubble") may increase as the amount of vapor increases, and may be directly proportional to the electrode voltage and / or current supplied to the tissue by the electrode as a larger volume of tissue is heated. Similarly, and / or the pressure within the bubble may increase as the amount of vapor increases, and may be directly proportional to the electrode voltage and / or current supplied to the tissue by the electrode as a larger volume of tissue is heated. A plasma may then be formed within the vapor cavity, at least in part, by ionizing the vapor, if the electrode is operated at a voltage large enough such that the resulting electric field strength within the vapor cavity exceeds the discharge threshold and generates plasma-induced ablation (the combination of which, when generated along the electrode, may generate plasma-induced incision). As a non-limiting example, the discharge threshold may be selected from the group consisting of an ionization threshold, an insulation breakdown threshold, a dielectric breakdown threshold, a glow discharge threshold, a plasma threshold, an ablation threshold, a disruption threshold, and combinations thereof. If the electrode voltage is large enough, the resulting electric field strength can enable a secondary discharge, producing an arc.Avoiding such arcing may be advantageous, as will be described elsewhere herein. The plasma may again allow electrical current to flow through the electrode, vapor, and tissue, thus causing further temperature increase. Bulk electrode temperature may be directly proportional to the amount of current flowing through the electrode, and / or surface collisions of ions and charged particles, chemical reactions, and radiation, which itself may be a function of the amount of plasma generated. Energy may be efficiently delivered to the target tissue structure to achieve thermal confinement within at least a portion of the target tissue structure in the vicinity of the electrode and / or vapor cavity, and to generate and / or sustain the vapor cavity. Thermal confinement may be achieved when the energy is deposited in the target at an energy deposition rate that exceeds the energy dissipation rate, such as when current flows nominally only through tissue in a time less than or equal to about the thermal time constant of the tissue, as may be achieved using a cyclic or pulsatile voltage. The thermal time constant may be a thermal relaxation time as defined by the size or shape or geometry of the electrode, the size or shape or geometry of the vapor cavity, and combinations thereof. The time constant may alternatively be defined as a mechanical response time, such as a displacement relaxation, due to the transient deformation of tissue adjacent to the collapsing vapor cavity. For a semi-infinite slab of material, the thermal relaxation time τ is: [ka] where d is the distance into the tissue and α is the thermal diffusivity of the tissue. For the sclera and cornea, α is ∼0.14 mm 2 ·s -1 For example, such a thermal relaxation time for a d=~2 μm damage range is τ=~28 μs. Damage is defined herein as at least partially denatured tissue or at least partially denatured tissue components resulting from mechanisms for generating incision, such as plasma, heating, etc. Such mechanical response times may be dictated by the compressibility and density of the material, which in turn may be related to tissue hydration. For most species, including humans, water may contribute ~76% of the weight of the corneal stroma.

[0059] In some embodiments, for examples relating to soft tissue, the following relationship is satisfied: [ka] can be used to approximate the mechanical properties of the tissue, where K and G are the bulk and shear moduli, respectively; [ka] where β is the tissue compressibility and the average elastic modulus of corneal tissue can range between ∼1 and ∼3 MPa. Thus, a sufficiently concentrated and rapid increase in temperature of a material (i.e., tissue or a component or constituent of tissue) can vaporize a quantity of that material. The vaporization can be explosive vaporization, disrupting the tissue, i.e., causing tissue "disruption", also known as "fracture", "explosion", and "ablation". The extent of the vapor cavity can decrease as the electric field strength squares the distance from the electrode (e.g., ∝r -2 ), may essentially mediate a plasma discharge process when operated as described within a compressible material, at least in part due to the transient mechanical deformation and displacement of the material, such as tissue, and the discharge may cease when the bubble grows to an extent where the distance from the electrode surface to the bubble surface cannot continue to support the discharge throughout the vapor cavity at the operating voltage, since the electric field strength may be proportionally reduced. Maintaining a glow-type discharge, or disabling an arc-type discharge, may be beneficial for producing precision incisions with minimal collateral damage. Flashing light may accompany the plasma. The rate of the flashing of light may depend on the speed. The intensity of the flashing of light may depend on the energy per pulse or power to the electrode.

[0060] In some embodiments, the required voltage and associated energy deposition can be reduced by decreasing the width of the electrode, as shown in FIG. 1B, which contains a plot 600 of the relationship between the negative voltage threshold for tissue vaporization versus the diameter of an elongated cylindrical electrode for .about.50 μs pulses using electrode lengths of .about.1 mm, .about.2 mm, .about.5 mm, and .about.10 mm, corresponding to curves 602, 604, 606, and 608, respectively. Such electrodes can be considered "extended electrodes" due to the aspect ratio between the width and length of the electrode. That is, an extended electrode has a cross-sectional distance that is significantly smaller than its incision length. This voltage can be made as low as possible, and cutting with this voltage can be possible when the voltage exceeds the breakdown threshold without allowing significant thermionic emission, where "significant" refers to an amount that significantly contributes to tissue thermal damage beyond that which would otherwise be present. The electric field around the electrode is as follows: [ka] is proportional to the distance r, such that: e is the electric field at the surface of the electrode, and r e is the radius of the electrode. Thus, the difference between the electrical potential on the surface of the electrode and that at a distance R from the nominally cylindrical elongated electrode is [ka] Thus, it may be said that the electric field is nominally spherical at distances greater than the length L of the electrode, and at distances comparable to L, the potential drops to zero, [ka] The power density of Joule heat generated by a current density j in a conductive material with resistivity γ can be assumed to yield: [ka] The minimum energy density A required to evaporate the surface layer of water in tissue can be calculated as: [ka] where ΔT is the temperature rise of the liquid layer during a pulse of duration τ and ρ=~1 g / cm 3 is the density of water, C=~4.2 J g -1 ·K -1 is its heat capacity. Therefore, the voltage U required for evaporation is [ka] This voltage and associated energy deposition can be reduced by decreasing the thickness of the electrode, i.e., the radius of the aforementioned wire. The pulse duration τ can be calculated based on the thermal relaxation time τ of the target tissue structure for a given electrode geometry. r For example, the 1 / e relaxation time for an oblong cylinder can be kept shorter than [ka] where: [ka] is the thermal diffusivity of the material, k is the thermal conductivity, which is given by α for a pure tungsten wire electrode of ∼20 μm diameter. tungsten =~0.66mm 2 ·s -1 and α tissue =~0.14mm 2 ·s -1 , τ of ~65μs r , i.e., ∼1 / 5 of that of an equivalent cylinder of water or tissue. From these curves it can be noted that for a wire electrode of ∼10 mm length and diameter less than ∼30 μm, utilizing a negative voltage of ∼−200 V may be adequate to dissect the target tissue structure while maintaining a ∼200 V margin to the positive breakdown threshold, as will be described elsewhere herein.

[0061] In some embodiments, the discharge may begin with the vaporization of tissue surrounding the electrode and continue when the voltage is high enough to bridge the ionized gas-filled vapor gap between the electrode and the tissue. If the voltage is not sufficient to maintain such a vapor cavity along the entire length of the electrode, the liquid may contact the electrode and allow electrical current to pass through the interface. The depth of heating may be proportional to the length of the liquid-electrode interface. Thus, the extent of the damage zone may increase with decreasing voltage for an otherwise fixed system. Higher voltages may correct this, but if the voltage exceeds both the negative and positive plasma thresholds, the electrode may become too hot and the plasma discharge may become self-sustaining, as will be explained elsewhere with respect to FIG. 3. Thermionic emission may be avoided, limiting concomitant damage to the tissue. Turbulence may destroy the vapor cavity and both the electrode and the tissue may be damaged. The electrode may be thin so that a low voltage may support the vapor cavity and the voltage may be slightly above the plasma threshold. A thin thickness of the vapor cavity may be maintained around at least a portion of the electrode at voltages below any plasma threshold. Translating the electrode may allow contact of a small area of ​​tissue, which may be conceptualized as a single contact point or punctate contact. Such punctate contact may produce a sudden vaporization and ignite a plasma discharge in a proportionally confined volume, thereby disrupting the tissue. After one section of tissue has been disrupted in this way, a different section of tissue may already be touching somewhere on the advancing electrode, leading to subsequent vaporization, discharge, and subsequent disruption in this area. The fusion of such disruptions may be considered an incision. The heat distribution around the punctate discharge may be nominally spherical. The extent of the heat deposition may be small, r -4where r is the radius of the discharge, the tissue damage zone may now depend more on the radius of the electrical discharge and less on the length of the electrode. If the radius of the point discharge is in the range of ∼10 μm, a sequence of such discharges may cut the tissue in a “perforating” or “intermittent” manner by repeatedly destroying different regions of the tissue along the electrode length (i.e., in non-contiguous locations, or equivalently, in non-overlapping regions), leaving a damage zone only about a few μm thick. These intermittent decomposition regions may be considered to constitute non-uniform decomposition. Such intermittent decomposition may be achieved if the electrode is allowed to flex (or equivalently, “deform” or “vibrate” or “bend” or “stretch”) as described elsewhere herein. Constant arcing may be avoided and the plasma may be made to remain in a glow steady state by repeatedly destroying regions of tissue, thereby modulating the electrode voltage and minimizing damage from hot ions and resulting thermal effects. The different regions of tissue within the target tissue structure that may be repeatedly destroyed may, but need not, be adjacent to one another.

[0062] 2A illustrates electrode 702 approaching tissue 2 along direction 12 with a gap 622 existing between electrode 702 and tissue region 620, the region of tissue closest to the elongated electrode. In this exemplary embodiment, both ends of electrode 702 are connected in parallel to driver 18 via connection 20, with the return path to driver 18 being via connection 22 from return electrode 24. Driver 18 may be considered to be an electrical energy source that provides electrical energy to the electrode to produce plasma in the target tissue structure.

[0063] FIG. 2B illustrates an initial instantaneous connection between the tissue 2 and the electrode 702 at the contact area 620, with the gap 622 decreasing to .about.0.

[0064] 2C illustrates a condition where the magnitude of the voltage on the electrode 702 exceeds at least a negative voltage plasma threshold in region 620 (not shown), which may cause vaporization of at least components of tissue 2 in tissue region 626, creating a vapor cavity 635, and allowing current 624 to flow to the return electrode 24, creating a damage zone 628. Such damage zone 628 may then be limited in extent to a volume of tissue immediately adjacent to tissue region 620, and any such tissue region 625 and 627 may become the next portion of tissue 2 to initiate vaporization in the same manner as region 620 previously did, as described elsewhere herein, creating an intermittent process, where non-contiguous portions of the electrode may contact associated non-contiguous portions of the target tissue during dissection. Discharge may begin with vaporization of tissue surrounding the electrode and continue while the voltage is high enough to bridge the gap vapor between the electrode and the tissue and ionize the vapor in the gap. If a portion of such an electrode does not have contact with tissue, as may be the case when, for example, a vapor bubble is formed centered in that region of the electrode, the electrode temperature may rise and increase resistivity. For example, as may occur when a portion of a wire draws more current than another portion of the wire when connected in series to a power source in a "power limited mode," the average power may remain constant, but localized overheating in the region of increased resistivity may cause a portion of the wire to vaporize and break down. However, this may be reduced (or avoided) if the electrodes are placed at a common voltage, as may occur when both ends of a wire are connected to the same location in a circuit (or "node"). In this exemplary configuration, when one portion of the electrode becomes more resistive due to overheating and current may pass through another portion of the electrode, the current through the heated region may decrease, as described above with respect to the series connection configuration, keeping the wire from breaking. The speed of the moving electrode may be selected to satisfy the condition of constant tension below the burst tension of the wire. Too little tension can reduce the rate. If the electrode is not in contact with the tissue, there can be no heat transfer from the electrode to the tissue and the electrode temperature can increase.The arc current may then increase due to the electrode temperature increase, initiating a positive feedback loop that may cause overheating of the tissue and / or electrode when the electrode is under relaxed and / or low tension conditions, which in turn reduces the likelihood that small areas of tissue will contact the electrode and produce the aforementioned intermittent discharge. Since the plasma threshold is polarity dependent, the discharge may act as a rectifier, and the rectified current may be used as feedback to cut off at about the minimum negative voltage threshold for plasma discharge, including, as a non-limiting example, operation at the glow discharge steady state. In this configuration, the damage zone may now depend on the radius of the electrical discharge instead of the electrode length. A perforation sequence of discharges, the range of which is in the ∼10 μm range, may result in a damage zone between ∼1 μm and ∼3 μm thick. The duty cycle of the power supply (e.g., driver 18 or “electrical energy source”) may be kept at ∼100% in this configuration due to the perforation discharge process.

[0065] 2D illustrates a condition in which the voltage on the electrode 702 falls below the plasma threshold and may fail to maintain a vapor cavity 635 such as region 626 in the previous figure, expanding the contact area 620 along the electrode 702 and producing an extended contact area 630 that is larger than the contact area 620, allowing more current 624 to flow from the electrode 702 through the tissue 2 to the return electrode 24, producing a damage zone 628 larger than that of FIG. 2C that may extend to a portion of the tissue 2 behind in the direction 12 via thermal conduction. If the electrode voltage fails to maintain the vapor cavity 635 along the electrode, tissue and / or liquid may contact the electrode, allowing large currents to pass through the interface. The extent of the damage may be proportional to the length of the electrode-tissue interface, i.e., the extended area 630. Thus, the damage zone extent may increase with decreasing voltage. Similarly, a large damage zone may also occur if no voltage is supplied to the electrode prior to its contact with the tissue, since a relatively large portion of the electrode may simultaneously contact the tissue before the discharge process is initiated. To avoid such damage, a threshold voltage may be applied to the electrode before it contacts the tissue and an incision is produced, as described with respect to FIG. 2C. Another way to protect the tissue from overheating may be by using a non-conductive liquid such as Electro Lube Surgical or a viscoelastic substance (e.g., Healon). Such a non-conductive liquid may act as both a coolant and a protection against current-related tissue damage, such as electroporation. For example, a non-conductive liquid may be injected into the cutting area to protect tissue near the target tissue that may be in the current return path. The non-conductive liquid may also be cooled before use.

[0066] FIG. 2E illustrates a condition in which the magnitude of the voltage on the electrode 702 may exceed both the negative and positive plasma thresholds, producing a contact area 620 extending along the electrode 702 and producing a vaporization area 626 that may exceed that of the vaporization area 626 in FIG. 2C. Similarly, more current 624 may flow from the electrode 702 through the tissue 2 to the return electrode 24 in this configuration than in FIG. 2C, producing a larger injury zone 628 than in FIG. 2C. An electrode voltage that exceeds both the negative and positive plasma thresholds may cause the electrode to heat up sufficiently to provide self-sustaining thermionic emission. Turbulence may disrupt the vapor cavity 635, damaging the electrode and / or tissue.

[0067] The elongated electrode may comprise a nominally circular cross-section (or "rounded") wire, and a reduction in electrode width may be comparable to a reduction in the diameter (or equivalently, its "cross-sectional distance") of the wire. The voltage may be kept as low as possible while still rupturing the tissue to avoid overheating the target tissue. The electric field from a nominally cylindrical electrode may tend to zero at a distance of about the electrode length, which may in turn cause an unnecessarily extended damage zone in the tissue when using such an electrode with an aspect ratio ≫ 1 (e.g., when the electrode comprises a long, thin wire). The intermittent process of tissue destruction as described herein may provide a reduced damage zone due to the inherent interruption of the current flowing through the tissue that may accompany the approach, since in the absence of tissue disruption, the electric current may nominally flow substantially only through the tissue when the tissue contacts the electrode.

[0068] Although typically circular in cross section, wires may be made in square, hexagonal, flattened rectangular, or other cross sections. Thus, electrodes may alternatively be constructed using conductors of nominally non-circular cross section, such as those of rectangular cross section. Such nominally non-circular cross section wires may be available from Eagle Alloys (Talbott, TN). Rectangular cross section electrodes may be produced by stamping foil sheets, such as those also available from Eagle Alloys (Talbott, TN). Non-circular cross section electrodes may further be configured such that their thinnest dimension is nominally parallel to the translation direction to provide electrode deformation capability along the translation direction and increased stiffness in the orthogonal direction. Conductive wires or threads with high melting points that form part of an electrical circuit may be referred to as filaments, as would be understood by one skilled in the art.

[0069] FIG. 2F illustrates a condition where the electrode 702 can be comprised of electrode regions 650, 652, and 654 that do not necessarily represent the entire incision length. The electrode as shown is deforming during the incision, and electrode regions 652 and 654 are displaced in the direction of motion 12 while electrode region 650 is not displaced, which can occur when at least one of electrode regions 650-654 is flexible. As a non-limiting example, configuring electrode 702 to be flexible, such as by using a thin wire for at least a single region of electrode regions 650-654, can provide such deformation capability. In an exemplary embodiment, the new region of tissue closest to the electrode, the most proximal tissue region 620, is now approached by electrode region 652, which was tissue region 625 in FIG. 2C, and can become the next portion of tissue 2 to cause vaporization in the same manner as region 620 was previously performed, creating a piece-wise incision. The shape of tissue 2 is altered by ablation of at least a single tissue region, thus causing a portion of tissue 2 to undergo vaporization in the same manner as previously performed region 620, creating a segmental incision, and the non-contiguous portions of the electrodes may contact the associated non-contiguous portions of the target tissue during the incision.

[0070] Figure 3 shows a ~8 mm long fish immersed in a bath of physiologically balanced salt solution. [ka] Plot 610 shows the relationship between polarity-dependent voltage thresholds for vaporization versus pulse duration for negative voltage discharges (curve 614) and positive voltage discharges (curve 612) measured using a pulsatile voltage delivered with a tungsten wire electrode, and observing such discharges using a camera. The lower threshold voltage for the negative discharge plateau may help to create an incision with less damage than that of the positive discharge plateau due to the attendant lower current. Thus, driver 18 may be configured to utilize a negative voltage bias.

[0071] A pulsating voltage waveform can be used to generate the plasma as described. In water, for example, the vapor cavity operates with a nominally sinusoidal waveform having a peak voltage of .about.300V. [ka] Away from the thick electrode, ~0.5 m s averaged over a bubble lifetime of ~500 μs -1The plasma expands at an average rate of 100 MHz, and may cease to discharge due to collapse of the vapor bubbles (and possible subsequent cavitation), which may transfer momentum between the material and the electrode. In this configuration, the time required to reignite the plasma may be on the order of milliseconds, which is long compared to the pulse period of the energized wave form at ~MHz steady state, which may require significantly larger voltages to sustain the discharge. However, if the distance between the tissue and the electrode surface is reduced, such as by moving the electrode, the destruction may be reinitiated more quickly. The velocity of the resulting cut produced by the plasma may be referred to herein as "tissue velocity." The frequency of the pulsatile electrode voltage may be configured in the ~MHz range, allowing multiple cycles during tissue destruction and / or bubble life. As a non-limiting example, the nominal type of the waveform may be selected from the group consisting of a sinusoidal waveform, a square waveform, a triangular waveform, a ramp waveform, a periodic waveform, an aperiodic waveform, and combinations thereof. The amount of time it takes for the electrode to move into contact with the tissue and for evaporation to occur may be longer than the amount of time it takes to complete the discharge process. When the electrode is not disrupting the tissue, it may be in a cool state, and the time when the electrode is in contact with the tissue and not disrupting it may cause tissue damage due to heat diffusion from the electrode into the tissue, which in turn may require more energy to overcome the reduced electrode temperature. Thus, a lower cutting duty cycle may produce more collateral thermal damage to the tissue than a higher cutting duty cycle.

[0072] In some embodiments, the inability to achieve thermal containment may result in collateral tissue damage. For example, this may be true for rigid electrodes, since while the velocity at all locations along the electrode is constant, the velocity of the tissue along the electrode may not be constant, i.e., there may be a distribution of tissue velocities in both time and space along the cutting edge of the electrode. A rigid electrode may only move as fast as the slowest cutting speed it achieves. That is, a rigid electrode may cut a complete path along its cutting edge in order to advance and further cut, and therefore may need to limit the instantaneous cutting speed by compacting areas of tissue onto the electrode prior to cutting, allowing only an average cutting speed. Hot spots along the cutting edge of a rigid electrode may provide point-like evaporation, but those same locations may then linger in the tissue, awaiting similar destruction elsewhere, even with a rigid elongated electrode. The time spent lingering may be longer than the thermal or mechanical response time of the tissue, resulting in collateral damage due to heat dissipation into the tissue, especially in the presence of excess liquid. A more efficient use of energy may be the desiccation of the next area of ​​tissue to be incised. Actuating a rigid electrode at too fast a translation rate may not allow complete incision and may cause "traction forces." Collateral damage may therefore be reduced if the electrode actuation rate is nominally matched to the discharge rate within the vapor cavity 635.

[0073] In some embodiments, the deformable electrode may move with a piecewise velocity profile through the material it cuts. That is, unlike a conventional rigid electrode, a portion of the deformable electrode may advance into the cavity (or "bubble") created by the vaporization event, then vaporize a new region of tissue before other regions along the electrode advance in a similar manner, thus allowing a velocity distribution of instantaneous cutting speeds along the electrode. Such a deformable electrode may be kept under tension along its length, which in turn may advance the deformable electrode through tissue at a rate determined, at least in part, by an average cutting rate, and at least in part, by a local cutting rate, which itself may be determined, at least in part, by the tension on the electrode. The mass (or mass density) and / or stiffness of the deformable electrode may at least in part dictate its ability to advance into the cavity created by the vaporization event. The average cutting rate can be influenced by moving the electrode or electrode assembly (e.g., along the x-axis, where +x may be defined as the intended direction of incision) using a translation element (or "translation device") and actuator. As non-limiting examples, the translation element may be selected from the group consisting of a translation stage, a linear stage, a rotary stage, a rail, a rod, a cylindrical sleeve, a screw, a roller screw, a traveling nut, a rack, a pinion, a belt, a chain, a linear motion bearing, a rotary motion bearing, a cam, a flexure, a dovetail, and combinations thereof. As used herein, the terms "stage" and "slide" are considered equivalent when used to describe a translation element, device, or system. As non-limiting examples, such actuators may be selected from the group consisting of a motor, a rotary motor, a squiggle motor, a linear motor, a solenoid, a rotary solenoid, a linear solenoid, a voice coil, a spring, a moving coil, a piezoelectric actuator, a pneumatic actuator, a hydraulic actuator, a fluid actuator, and combinations thereof. Alternatively, the electrode assembly may be manually actuated.

[0074] In some embodiments, the tension may be selected to accommodate the stiffness of the material being used to form the electrode, as may be represented by its elastic modulus. By way of non-limiting example, the elastic modulus may be selected from the group consisting of flexural modulus, Young's modulus, bulk modulus, section modulus, and shear modulus. For a deformable electrode that is supported by a support structure at least at a single end, the elastic modulus E of the electrode material may be determined by the allowable deflection distance. [ka] where L is the unsupported length of the electrode, and I is the second moment of area for the cross-sectional shape of the electrode, which can be used to determine the tension F for the electrode relative to the cross-sectional shape of the electrode, as explained previously herein, ∼2r e For a rectangular electrode, [ka] where w is the thickness of the electrode in the direction perpendicular to the deflection and h is the thickness of the electrode in the direction of deflection. Similarly, the second moment of a cylindrical electrode, such as a wire, can be given by: [ka] where r represents the radius of the cylinder.

[0075] In some embodiments, there may be a trade-off, particularly in systems with moving elongate electrodes, between the characteristic range of an electrode (i.e., “dimension” or “thickness” or “size”) (e.g., diameter in the case of a wire or other such elongate electrode) and its corresponding mechanical stability, and thus the strength and durability of the device constructed thereby. Thus, a thin wire electrode that is tensioned and stretched may relax and provide increased mechanical stability over a thin wire electrode. Increased mechanical stability may represent increased incision accuracy (e.g., such an electrode may be less likely to drift laterally with respect to the incision direction). Alternative embodiments may further comprise a tensioning element mechanically coupled to the electrode to provide a more constant tension on the electrode nominally. A thin deformable elongate electrode as described herein has a fundamental frequency (or equivalently, a mechanical resonance frequency)

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0076] In this configuration, such an electrode can be translated in the x-direction, displaced ("repelled") ~20 μm, resulting in a local peak velocity [ka] , which is constrained to motion primarily along the x-axis, which is the cutting direction (i.e., parallel to the direction of electrode translation, or equivalently, transverse to the direction of extension), thereby minimizing lateral errors to the intended cutting direction. Such a configuration may provide reduced thermal damage and / or reduced traction forces compared to that of a system consisting of rigid electrodes, since primary heat deposition and / or heat spread may be relatively reduced by utilizing such deformable electrodes to better match tissue velocities. Such deformable (or "flexible") electrodes may provide local velocities of the electrode that are inversely proportional to the deflection on the electrode, which may tend to follow the plasma and relieve increased tension thereon, with velocities of ∼1 m s -1 , and thus may move faster than its associated plasma cuts tissue. In doing so, the electrode may be said to "flex" or "deform" or "vibrate" or "stretch" or "bend". Thus, an elongated electrode as described herein may vibrate transversely to the axis of elongation of the electrode. As a non-limiting example, the following table lists various configurations of electrode materials, sizes, and their corresponding mechanical resonant frequencies. [Table 1-1] [Table 1-2]

[0077] In some embodiments, thermal containment can be achieved if the discharge is produced within a single cycle of the pulsating voltage waveform, such as within a nanosecond time frame. From the laser-tissue interaction field, it can be seen that explosive vaporization with a nanosecond pulse can produce peak temperatures of 200° C., and the resulting volume of the void (or “funnel hole” or “cavity”) can exceed the volume substantially heated by 50%. For example, photodisruption is known to produce such a damage volume. The ejection of steam and / or moisture and / or debris from the incised area can inhibit the formation of an arc discharge between the electrode and its environment, even at high temperatures, which a thin deformable electrode can inherently provide, especially if the deformable electrode contacts tissue along an area that is less than its circumference and produces a void that is larger than the interaction volume as described for certain effects of photodisruptive nanosecond laser pulses. This extended damage volume can aid in the ejection of debris and / or moisture and / or steam. For example, the ejection of moisture. [ka] The energy E required to heat the sphere from ~20°C to ~200°C is [ka] However, a bubble smaller than the extent of the electrode may nevertheless provide a resulting cavity of sufficient extent to allow passage of the entire electrode due to the resulting increase in infundibulum volume, as may be the case with tissue contact along only 1 / 2 to 2 / 3 of the electrode circumference (or equivalently, only 1 / 2 to 2 / 3 of the electrode diameter as geometrically projected onto the tissue). In this case, the corresponding reduction in energy required to induce a plasma is [ka] and the resulting infundibulum extent may be, as may be particularly true for mechanically compliant tissues, [ka] As a non-limiting example, a power of ∼15 W may be sufficient to accommodate an entire electrode of ∼10 mm incision width, with a pulse repetition frequency ("PRF") of ∼1 MHz (or equivalently, ∼1.5 W mm -1 (average linear average power density) delivered to the electrode, and τ pulse For example, for PRF = 1 MHz and E = 1 μs, it can provide an energy per cycle (or "pulse") of 15 μJ. pulse = ~15μJ, works as described, ~10mm long [ka] For a wire electrode, the effective ablation length per pulse is given by the following relationship: [ka] can be observed, and L a can be ∼1.32 mm. Furthermore, L a does not have to comprise a single continuous length, but rather the individual lengths of the interrupted zones (or equivalently, non-overlapping regions) may be approximately L per pulse. a The electrode may also be comprised, at least in part, of separate instances of discrete ablations or discrete ablation regions distributed along the entire electrode length, such that they may sum to a value of [ka] L etc. a The effective translational velocity (or "rate") v, determined by a Continuing with the previous exemplary configuration, a .about.10 mm long [ka] The total effective length along the electrodes is ~1.32 mm, which is ~660 mm s -1 The effective translation velocity v a, while the electrode may deform as it cuts, and the actual local peak velocity of at least a single portion of the electrode may be greater than the velocity of underlying translation via the actuator, v, as described elsewhere herein. t and due to the elasticity of the electrode and the tension applied thereto, v a That is, v t v a does not have to be equal to v t is ~1mm s -1 and ~5,000 mm s -1 Optionally, v t is ~10mm s -1 and ~1,000 mm s -1 Optionally, v t is ~50mm·s -1 and ~500mm·s -1 As a non-limiting example, PRF=~1 MHz and E pulse = ~10mm long under ~300mN tension operating with ~15μJ [ka] The tungsten wire is ~300mm·s -1 Peak V t , can be translated with a plasma to incise the corneal tissue with minimal concomitant damage. In view of the foregoing, the system can be configured to allow the electrode velocity to nominally match the tissue velocity with the moving front of the plasma-induced bubble along the length of the deformable electrode being translated through the tissue to be incised. Variable speeds can be used as discussed elsewhere herein.

[0078] FIG. 4 shows that the tensioned electrode assembly 5 may comprise a tension element 700, which in turn may be operatively coupled to the electrode 702 and affixed to the electrode subassembly 4 via attachments 704 and 706 to allow the electrode 702 to flex while in contact with the tissue 2 (not shown in this figure). The incision portion of the electrode 702 may comprise only a portion of the conductive portion of the electrode 702. The radius 708, located on the arms 710 and 712, may provide a smooth surface for the electrode 702 during extension to avoid excessive strain that may be imparted at a more abrupt transition. The arms 710 and 712 may be considered at least a part of a support structure intended to provide mechanical stability to at least a portion of the electrode 702. A gap may exist between the arms 710, 712 and may serve to receive tissue before and / or during and / or after creating the incision, as shown in this embodiment. In some embodiments, the tensioned electrode assembly 5 comprises a support structure as described herein.

[0079] In some embodiments, a processor, e.g., a controller, is operably coupled to the elongated electrode and provides movement to the elongated electrode. For example, the processor can be configured with instructions provided to control an actuator to move one or a component of the electrode assembly. In some embodiments, the processor is configured with instructions, for example, to advance the electrode distally and retract the electrode proximally.

[0080] In some embodiments, the elongated electrode is sized for insertion into the tissue, and the processor is configured with instructions to dissect the tissue with the electrode to define a volume of dissected tissue within the pocket. The volume can be configured in many ways, but in some embodiments, the volume comprises a shape profile, for example, a shape profile of a corneal strip. In some embodiments, the processor is configured with instructions to move the electrode with a first movement to define a first dissected surface on a first side of the tissue volume, and with a second movement to define a second dissected surface on a second side of the tissue volume. In some embodiments, the processor is configured with instructions to advance the electrode distally to define a first surface on the first side of the tissue volume, and retract the electrode proximally to define a second surface on the second side of the tissue volume. In some embodiments, a gap extends between the elongate electrode and the support structure, the gap being sized to receive tissue such that the tissue extending into the gap is incised as the electrode is retracted proximally.

[0081] In some embodiments, the movement of the electrodes is coordinated with the shape of one or more contact plates to define the incised tissue volume. In some embodiments, the contact plate comprises a first configuration to define a first surface on a first side of the tissue volume and a second configuration to define a second surface on a second side of the tissue volume. In some embodiments, the first contact plate comprises a first shape profile to define a first surface on a first side of the tissue volume and a second shape profile to define a second surface on a second side of the tissue volume, for example, the first and second surfaces of a corneal strip comprise the tissue volume. In some embodiments, the contact plate comprises a plurality of actuators operably coupled to a processor, the processor configured with instructions to shape the contact plate with a first surface profile for the first incision and to shape the contact plate with a second profile for the second incision. In some embodiments, the processor is configured with instructions to shape the contact plate with a first profile, cut a first side with a first shape profile, shape the contact plate with a second profile, and cut a second side with a second profile, wherein the total time is, for example, about 10 seconds or less, e.g., 5 seconds or less, or 2 seconds or less.

[0082] The support structure may be fabricated at least in part from a material selected from the group consisting of tungsten, nitinol, steel, copper, brass, titanium, stainless steel, beryllium-copper alloy, cupronickel alloy, palladium, platinum, platinum-iridium, silver, aluminum, polyimide, PTFE, polyethylene, polypropylene, polycarbonate, poly(methyl methacrylate), acrylonitrile butadiene styrene, polyamide, polylactic acid, polyoxymethylene, polyether ether ketone, polyvinyl chloride, polylactic acid, glass, ceramic, and combinations thereof. The tension element 700 may be connected directly to at least a portion of the electrode subassembly 4 as shown, or alternatively to at least a portion of a subsequent element to which the electrode subassembly 4 is attached, such as the coupler 52 or the electrode assembly mount 17. As non-limiting examples, the tension element 700 may be a spring, a coil spring, a leaf spring, a torsion spring, an elastic mesh, a hinge, a living hinge, and combinations thereof. The deformable electrode may be supported by a support structure and allowed to deform while generating plasma-induced incision in the target tissue or target tissue structure. The electrode (e.g., electrode 702 or a portion thereof) may be at least partially composed of a material selected from the group consisting of tungsten, nitinol, steel, copper, brass, titanium, stainless steel, beryllium-copper alloy, cupro-nickel alloy, palladium, platinum, platinum-iridium, silver, aluminum, and combinations thereof. Alternatively, the electrode may comprise a wire composed of the same materials listed immediately above. Alternatively, the electrode may be coated in an area to inhibit conduction and / or incision in that area. Alternatively, tubing may be used in place of a coating to insulate an area of ​​the electrode. Such coatings or tubing may be selected from the group consisting of polyimide, PTFE, polyethylene, polypropylene, polycarbonate, poly(methyl methacrylate), acrylonitrile butadiene styrene, polyamide, polylactic acid, polyoxymethylene, polyether ether ketone, polyvinyl chloride, polylactic acid, glass, ceramic, and combinations thereof.The electrodes (e.g., electrode 702) may be wires having a diameter between 3 μm and 300 μm. Alternatively, the wires may have a diameter between 10 μm and 50 μm. Alternatively, the wires may have a diameter between 12 μm and 17 μm. The tension element 700 was tensioned to 295 mN, which may also correspond to an elongation of 0.5%. [ka] As may be the case for tungsten wire in, the electrode may be configured to provide a tension such that the resulting force on the electrode is .about.80% of the rated or measured yield strength of the electrode or its material. Optionally, the tension may be between .about.50% and .about.95% of the yield strength. Optionally, the tension may be between .about.70% and .about.85% of the yield strength. Other configurations may also be proportioned using relationships related to moment of area second as described herein above with respect to allowable deflection distance (e.g., [ka] 4.7 N or 3.8 N for a nominally pure tungsten wire with a diameter of 4.7 N. The coupler 52 may be operatively coupled to the cutting electrode mechanism 502 via the coupler 74. As a non-limiting example, the coupler 74 may be a receptacle configured to receive a disposable module consisting of the element electrodes 4, the coupler 52, and the electrode mounting portion 17, the electrode mounting portion 17 comprising mating features compatible with those of the coupler 74, such as threads, clasps, snap fittings, and combinations thereof. The cutting electrode mechanism 502 may further comprise mating features compatible with those of the couplers 71 and 72, which may themselves be mechanically coupled to the actuators 50 and 504, respectively, to provide an axis of motion to move at least a portion of the electrode subassembly 4 and / or the tensioned electrode assembly 5 to create an incision in the tissue 2 (not shown). Alternatively, by way of non-limiting example, the element electrode subassembly 4, coupler 52, electrode mount 17, cutting electrode mechanism 502, and coupler 74 may be packaged within the probe body 26 as a disposable module configured to engage a more complete dissection system and actuate the electrode or electrode or probe assembly along the axis of motion 12. Although not shown for reasons of clarity, at least a portion of the probe body 26, including the tensioned electrode assembly 5, may be adapted to move using a translation element to ensure mechanical stability and accuracy along at least a single direction of motion.

[0083] FIG. 5 shows a tensioned electrode assembly 5 similar to that of FIG. 4, where the radius 708 may further include a channel 720 within which the electrode 702 may be placed to minimize positional errors due to unintentional electrode movement, particularly transverse to the intended incision direction. The tensioning element 700 may be configured as a living hinge (or hinge, as shown) within or along the arms 710 and 712. The arms 710 and 712 may be made of a notched rigid material, as shown, to provide the living hinge 722. As non-limiting examples, materials suitable for producing living hinges may be selected from the group consisting of polyethylene, polypropylene, polycarbonate, poly(methyl methacrylate), acrylonitrile butadiene styrene, polyamide, polylactic acid, polyoxymethylene, polyether ether ketone, polyvinyl chloride, beryllium copper, and combinations thereof. In cases where the living hinge 722 is integral to the arm 710 or 712 and an electrically conductive material may be selected, such cutting electrode may be soldered, brazed, adhered with a conductive adhesive, and / or welded to the arm. In cases where the living hinge is integral to the arm 710 or 712 and an electrically insulating material is selected, the electrode 702 may be otherwise adhered to the arm or soldered, brazed, and / or welded to an adjacent conductive material.

[0084] FIG. 6 illustrates system 800, which is a system for dissecting tissue such as ocular tissue, including cornea, limbus, and stromal tissue. System 800 may include a tensioned electrode assembly 5 similar to that of FIGS. 4 and 5. Electrode subassembly 4 may be coupled to electrode mounting portion 17 via coupler 52. As a non-limiting example, coupler 52 may be made to be at least partially electrically insulated. Electrode subassembly 4 may include arms 710 and 712, electrode 702, and tensioning element 700 operably coupled to electrode 702 and affixed via attachments 704 and 706 to create tensioned electrode assembly 5 such that tensioning element 700 may allow electrode 702 to stretch while in contact with tissue 2. Attachments 704 and / or 706 may be achieved via soldering, brazing, adhesives, compression fittings, crimping, and combinations thereof. Radii 708 located on arms 710 and 712 may provide a smooth surface for electrode 702 during extension to avoid excessive strain that may be incurred at sharper corners. Tensioning element 700 may be connected directly to a conductive portion of electrode 4 or alternatively to a subsequent element to which electrode 702 is configured, such as coupler 52 or electrode mount 17. An incision may be made by moving along axis of motion 12. In this exemplary configuration, tensioned electrode assembly 5 may consist of elements 700, 702, 704, 706, 708, 710, and 712, all of which may be constructed at least in part from conductive materials and thus held at approximately the same voltage by driver 18 (not shown), all of which may be considered to comprise tensioned electrode assembly 5. Alternatively, electrode subassembly 4 and tensioned electrode assembly 5 may be identical. Alternatively, some of the aforementioned elements may be at least partially comprised of an electrically insulating material and therefore may not be at the same electrical potential as other elements that are at least partially comprised of a conductive material, and the electrode subassembly 4, as shown, may be considered to be a subsystem of the suspended electrode assembly 5, with only those elements that are at least partially comprised of a conductive material.As non-limiting examples, the tensioning element 700 may be a spring, a coil spring, a leaf spring, a torsion spring, an elastic mesh or web, a hinge, an integral hinge, and combinations thereof. The torsion spring may be such as that found in a stapler. As non-limiting examples, the conductive electrode material may be selected, at least in part, from the group consisting of tungsten, nitinol, steel, copper, brass, titanium, stainless steel, beryllium-copper alloy, cupro-nickel alloy, palladium, platinum, platinum-iridium, silver, aluminum, and combinations thereof. Alternatively, the electrode 702 may be at least in part made of wires made of the same material. Alternatively, the electrode subassembly 4 may be at least in part made of elements made of an electrically insulating material. Alternatively, the electrode subassembly 4 may be coated in certain areas to inhibit conduction and / or dissection in those areas. Similarly, tubing may be used in place of a coating to insulate areas of the electrode assembly. By way of non-limiting example, such coatings or tubing may be selected from the group consisting of polyimide, PTFE (e.g., Teflon), polyethylene, polypropylene, polycarbonate, poly(methyl methacrylate), acrylonitrile butadiene styrene, polyamide, polylactic acid, polyoxymethylene, polyether ether ketone, polyvinyl chloride, polylactic acid, glass, ceramic, and combinations thereof. A return electrode (not shown) may be placed on or near the patient's eye and connected to the driver 18. A series load of between .about.150 .OMEGA. and .about.500 .OMEGA. may be placed in line with the electrode to provide a current limit. Coupler 52 may be operably coupled to cutting electrode mechanism 502 via coupler 74. Alternatively, as a non-limiting example, the element electrode 4, coupler 52, electrode mounting portion 17, cutting electrode mechanism 502, coupler 74, or a subset thereof, may be packaged as a disposable module configured to engage within the probe body 26 and, in turn, the system 800 via couplers 71 and 72, which may have mating features compatible with those of the actuators 50 and 504, respectively, such as threads, clasps, snap joints, and combinations thereof.Actuator 504 provides an axis of motion (or equivalently, e.g., "translation" along the direction of motion of axis of motion 14) and may be coupled to position encoder 51 via connection 53, and both position encoder 51 and actuator 50 may be connected to translation device and / or actuator driver 57 via connections 55 and 59, respectively. By way of non-limiting example, connections 55 and 507 may comprise at least one of the following: mechanical couplers, electrical couplers, magnetic couplers, and optical couplers. Actuator 504 also provides an axis of motion (e.g., axis of motion 12) and may be coupled to position encoder 506 via connection 505, and both position encoder 506 and actuator 504 may be connected to actuator driver 508 via connections 509 and 511, respectively. It should be noted that only a single axis of motion may be relied upon in practicing certain embodiments of the present disclosure, such as in the creation of a corneal flap utilizing a single incision. The motion axes 14 and 12, which are the motion axes for the actuators 50 and 504, respectively, may be configured to be orthogonal, or at least not collinear. The actuators 504 and 50 may be configured to actuate the spanned electrode assembly 5 or a portion thereof along the motion axes 12 and 14. The position encoders 51 and 506 may be mechanically coupled to the module onto which the electrode subassembly 4 is mechanically coupled via connections 55 and 507, respectively, to provide more reliable position information than non-collocated sensors may provide. Alternatively, the actuator 50 may be configured to correspond to (or "move along") the motion axis 14 and made to actuate (or "translate") the contact plate 804, and the connection 55 may be made with the contact plate 804 or a structure supporting the contact plate 804. The driver 18 may be configured to provide a controlled voltage and / or a controlled current to the electrode 4. The driver 18 may provide an alternating voltage and / or current waveform to the electrode 702.Such waveform types may be selected from the group consisting of, by way of non-limiting example, pulsating, sinusoidal, square, sawtooth, triangular, fixed frequency, variable frequency, and combinations thereof. Driver 18 may be configured to supply a waveform with a peak-to-peak full range voltage between 50V and 1,000V. Alternatively, driver 18 may be configured to supply a waveform with a peak-to-peak full range voltage between 200V and 500V. Driver 18 may be configured to supply a waveform with a carrier (or "base") frequency between 10kHz and 10MHz. Alternatively, driver 18 may be configured to supply a waveform frequency between 500kHz and 2MHz. Alternatively, driver 18 may be configured to supply a waveform frequency between 800kHz and 1.2MHz. Burst duration may also be used, as well as electrode velocity v. t The driver 18 may further be modulated to generate a duty cycle comprising bursts of pulses at a modulation frequency between 100 Hz and 3 MHz. The duty cycle may be between 0.01% and 100%. Alternatively, the duty cycle may be between 50% and 100%. Alternatively, the duty cycle may be between 95% and 100%. The driver 18 may be configured to provide an average power between 1 W and 25 W. Alternatively, the driver 18 may be configured to provide an average power between 12 W and 18 W. The driver 18 may be configured to provide an energy per cycle (or equivalently, "energy per pulse") between 1 μJ and 100 μJ. Alternatively, the driver 18 may be configured to provide an energy per cycle between 5 μJ and 50 μJ. Alternatively, the driver 18 may be configured to provide between .about.10 .mu.J and .about.20 .mu.J of energy per cycle.

[0085] In some embodiments, the flap may be described as an incision that results in a "flap" of tissue that can be elevated and pivoted on a "hinge" to provide access to the tissue beneath. As a non-limiting example, cutting a section of tissue to a depth of 130 μm and cutting a plane at that depth just below the tissue surface may result in a flap with the uncut edge as its hinge. The flap may be separated by completing the uncut edge of the exemplary incision. In some embodiments, a pocket may be described as an incision that separates a first depth (or layer) of tissue from a second depth (or layer) of tissue section without necessarily creating a flap. As a further non-limiting example, cutting one side of tissue to a depth and cutting a plane at that depth just below the tissue surface may result in a pocket.

[0086] In some embodiments, due to the plasma discharge at the electrode 702, a significant drop in the input impedance of the driver 18 may cause a local current spike, which in turn may destroy the electrode and / or cause damage to tissue. The power delivered to the electrode (or equivalently, "delivered power" or equivalently, "maximum power output") may instead be limited to avoid such a situation. Average power suitable for practicing embodiments of the present disclosure is ∼1 W mm−1, particularly during glow discharge. -1 and ~10W mm -1 The delivered power may be between v and t. The delivered power may be higher during the initial exposure to more reliably initiate dielectric breakdown. Alternatively, the voltage and / or current waveform (or alternatively, the power control signal) used to power the electrode 702 may further be adjusted to account for the instantaneous or expected length of tissue engagement and / or the electrode translation velocity v t may be modulated or adjusted to be proportional to

[0087] As a non-limiting example, when dissecting the cornea, the voltage may be increased from an initial value corresponding to when the electrode 702 is about to or is expected to initially engage tissue and is nominally oriented toward a more central corneal region to a higher voltage corresponding to when the electrode 702 is or is expected to traverse the central cornea and thus has a relatively longer tissue engagement length than initially, the electrode voltage may then be decreased as the electrode 702 continues to traverse the cornea 2 and dissect tissue, with an essentially shorter engagement length, the decrease may be, but need not be, configured to be the opposite of the initial increase. The position of the electrode 702 within the cornea 2 may be inferred using an encoder in the translation subsystem, as described elsewhere herein. In one embodiment, the voltage provided by the driver 18 is such that the tensioned electrode assembly 5 is tensioned by the tensioning element 700 to ∼300 mN and ∼2,000 mm s along the direction 12 with the initial electrode location being between ∼4 mm and ∼7 mm from the side closest to the target tissue to be incised. -2 With a constant acceleration of ~300mm s -1 The maximum rate of (i.e., v t, max ) for the incision of the electrode 702, which is translated by [ka] The electrode may be configured to deliver a maximum peak-to-peak bipolar nominally sinusoidal voltage of ∼500V (with amplitudes of both ∼+250V and ∼−250V relative to a nominal neutral voltage, which need not be ground voltage), with a PRF (or “carrier frequency”) of ∼1 MHz, which may ramp up from ∼0V to a maximum amplitude during the initial ∼50 μs of translation, and then ramp down back to ∼0V during the final ∼100 μs of translation. Note that such constant acceleration may result in a linear velocity profile in which the electrode may be forced to rest inside the target tissue, as may be required to create a flap or corneal strip, as opposed to a complete incision, as will be described elsewhere herein.

[0088] In some embodiments, the monitor 514 may be configured to monitor the voltage and / or current supplied to the electrode 702 via connection 516 and provide data regarding the voltage and / or current to the driver 18 via connection 518. The data regarding the voltage and / or current of the electrode 702 may be in the form of a signal from the comparator. The system controller 60 may be operatively coupled to the driver 18 via connection 62, which may be at least a unidirectional connection. Alternatively, the connection 62 may also be a bidirectional connection in which the controller 60 is at least capable of sensing and / or responding to signals from the driver 18. The signal from the monitor 514 may also be provided to the system controller 60 and acted upon therein, thereby controlling the incision made by the electrode 702. The monitor 514 may reside within the system controller 60 and / or communicate with the system controller 60 via the driver 18. Such a signal may be a safety signal regarding the sensed voltage or current, such as when the voltage or current is outside of a defined boundary. In further alternative embodiments, the driver 18 and / or the monitor 514 may provide feedback to the controller 60 or use such feedback internally. Such feedback may be, by way of non-limiting example, EMF or current feedback and may be useful in determining when the electrode 702 contacts tissue and / or the status of the plasma. Such a status may be, for example, whether the plasma is in a glow discharge steady state. The connection 65 connects the controller 60 and the actuator 50 and is at least a unidirectional connection. The actuator 50 may consist of at least one electric motor and may further include a position encoder. The connection 65 may alternatively be a bidirectional connection and signals such as position, velocity, acceleration, out of bounds error, etc. are shared between the controller 60 and the actuator 50. In further alternative embodiments, the actuator 50 may provide feedback to the controller 60 or use such feedback internally or may share such feedback as a signal with the controller 60.Such feedback may be, by way of non-limiting example, force feedback and may be useful in determining when the electrode 702 contacts tissue or when it exerts excessive force on the tissue to be incised. Similarly, connection 67 connects the controller 60 and the power source 70 and is at least a unidirectional connection. In further alternative embodiments, the power source 70 may provide feedback to the controller 60 or use such feedback internally and may share such feedback as a signal with the controller 60. Such feedback may be, by way of non-limiting example, an error signal. Such an error signal may be a temperature error, an input voltage error, an output voltage error, an input current error, an output current error, etc. Similarly, connection 68 connects the controller 60 and the user interface 80 and is at least a unidirectional connection from the user interface 80 to the controller 80. In further alternative embodiments, the user interface 80 may provide feedback to the controller 60 or use such feedback internally and may share such feedback as a signal with the controller 60. For example, user interface 80 may be a graphical user interface or a button or foot pedal used to signal actuator 50 to move electrode subassembly 4 and / or tensioned electrode assembly 5 to cut tissue. Actuator drivers 57 and 508 may be connected to system controller 60 via connections 65 and 510, respectively. User interface 80 is connected to system controller 60 via connection 68, through which user commands may be transmitted.

[0089] In some embodiments, the system controller 60 comprises a processor configured with instructions to determine a profile of tissue to be removed from the eye and provide refractive correction. The processor can be configured to determine a geometric profile of one or more plates used to provide refractive correction for the patient. Also, although reference is made to the controller 60, the controller 60 may constitute a component of a distributed computing system and may be operatively connected to one or more processors as described herein, such as a distributed processing system.

[0090] In some embodiments, the system 800 may further comprise a contact plate 804, a support element 802, a suction element 810, and an associated vacuum device that may be used to immobilize the contacted tissue 2. An incision 42 may be made in the tissue 2 (the cornea and / or corneal stroma in this exemplary embodiment) by moving at least a portion of the tensioned electrode assembly 5 along the axis of motion 12 and using the actuator 504 to generate a scaffold 43. The contact plate 804 may be incorporated to flatten the cornea by moving it along the axis of motion 14 over the anterior surface of the cornea with the actuator 50. The contact plate 804 may further comprise a contact surface 806 (not shown). The contact plate 804 may be used to flatten the cornea, particularly when the contact surface 806 is nominally approximately planar. As a non-limiting example, the contact plate 804 may be configured to be a flat glass window to allow visibility therethrough. As non-limiting examples, the contact plate 804 may be made of a material selected from the group consisting of glass, crystalline lines, ceramics, metals, polymers, and combinations thereof. A contact element 808 (not shown) may be disposed on the distal surface of the contact plate 804 and provide a clean and / or sterile surface for contact with the tissue 2 and may be configured as a thin, conformal peelable and adhesive sterile barrier, which may also be disposable. As non-limiting examples, the contact element 808 may be made of a material selected from the group consisting of polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), oriented PP (OPP), biaxially oriented (BOPP), polyethylene terephthalate (PET), and combinations thereof. The contact plate 804 may be supported, at least in part, by the support 802. The support 802 may further at least partially be a support element for the tensioned electrode assembly 5, such as arms 710 and 712, thereby also supporting the electrode 702 and tensioning element 700 and forming at least a part of the electrode subassembly 4 and / or tensioned electrode assembly 5. Thus, the arms 710 and 712 may be considered to be a support structure for the electrode 702.Alternatively, the support 802 may be operably coupled to the probe body 26 and / or the sheath 6. Alternatively, the contact plate 804 may be moved relative to the tissue 2 along with the support 802. The suction element 810 may be used to stabilize the eye containing the tissue 2 relative to the contact plate 804 and / or the electrode 4. The suction element 810 may be configured as a nominally open annular ring as shown, or alternatively by any other applicable structure for achieving fixation to the eye, such as a single open pocket or multiple open pockets. The suction element 810 may be operably coupled to a vacuum pump 850 via a vacuum line 870 to provide negative pressure within the suction element 810. For patient safety and system reliability, a vacuum switch 852 and / or a vacuum sensor 854 may be installed between the suction element 810 and the vacuum pump 850 and connected via connections 860 and 862, respectively. System controller 60 may be connected to vacuum pump 850, vacuum switch 852, and vacuum sensor 854 via electrical connections 864, 866, and 868, respectively. In this configuration, actuator 50 may correspond to axis of motion 14 and be configured to actuate (or "translate") contact plate 804, and connection 55 may be made with contact plate 804 or such structure supporting contact plate 804. Contact plate 804 has a linear motion of 0.1 mm·s. -1 and ~1,000 mm s -1 and in alternative embodiments, the translation may be performed at a rate or speed between 10 mm s -1 and ~100mm·s -1 The motion corresponding to actuator 50 may be configured to be at least partially simultaneous with actuator 504 or its velocity profile.

[0091] In some embodiments, the system 800 may be further configured such that the tensioned electrode assembly 5 comprises, at least in part, an electrode 702. The electrode 702 may comprise a tungsten wire of ∼12.5 μm diameter and at least ∼99% purity, extending across the arms 710 and 712 to form a bridging distance of ∼12 mm, for example, using a mechanical coil spring to apply a tension of ∼300 mN on the electrode 702.

[0092] In some embodiments, the incision may form a flap or pocket or a combination thereof based on whether the electrode cut width is approximately greater than or approximately equal to the lateral extent of the target tissue structure to be incised and whether the electrode is penetrated laterally outward from the tissue. That is, a flap may be created in the anterior aspect of the cornea by using the contact plate 804 to flatten or otherwise compress the anterior corneal surface, resulting in a lateral dimension for the incision 42 between .about.3 mm and .about.11 mm, or alternatively, between .about.8 mm and .about.10 mm (all of which may be less than the aforementioned bridging distance to provide a flap incision). The flap incision may be configured to provide a D-shaped incision 42 as shown, with the straight sections of the D-shaped incision being the hinge portions. Similarly, a pocket incision may be created when the electrode bridging distance is less than the lateral extent of the compressed cornea presented to the electrode. Alternatively, a combination flap / pocket incision may be created using a pocket incision configuration, allowing the electrodes to traverse the entire distance through the cornea, resulting in an incision that is shaped as a fully rounded rectangle or a partially rounded rectangle (e.g., when configured with no straight cut portions). In an alternative embodiment, the driver 18 supplies a sinusoidal waveform that may have a peak-to-peak full range voltage of ∼250 V, at a frequency of ∼1 MHz and a power limit of ∼15 W, and provides a ∼200 mm s along the direction of motion 12, utilizing steps 102-122 of flowcharts 100 and 200, as shown in Figures 7 and 9. -1 and ~0mm·s -1The rate of electrode translation between (i.e., while the electrode is stopped at the edge of the incision, v t =~0mm s -1 ) to incise corneal tissue. Step 202 of flowchart 200 may be utilized to turn power on and off to the electrodes in coordination with the movement of the electrodes and contact plate 804 such that the electrodes are provided with a voltage of nominally .about.0V during intermediate periods while the electrodes move in a first direction and then in a second direction, as may be the case when contact plate 804 is moved along movement direction 14 to remove a portion of tissue (e.g., a "chip" of intrastromal tissue). Alternatively, electrode voltage and / or power may be a function of electrode speed and / or position and / or cutting range, as described elsewhere herein.

[0093] Alternatively, variable acceleration may be utilized to generate a motion profile for the electrode that results in a non-linear velocity profile. Such a motion profile requires a higher order control model and incorporates “jerk” and / or “acceleration” and / or “acceleration-acceleration” factors, as a non-limiting example, v within the first ∼50 μs. t Asymmetric acceleration / deceleration may be provided such that the range of is similar for the final ~10 μs.

[0094] The speed and / or speed profile and / or effective incision width may be taken into consideration when controlling (eg, "modulating") the power to the electrodes.

[0095] As non-limiting examples, the power to the electrode 702 may be adjusted by selecting a maximum value of a parameter selected from the group consisting of voltage, current, carrier frequency, modulation frequency, duty cycle, power set point, power limit, energy per pulse set point, energy per pulse limit, and combinations thereof.

[0096] As a non-limiting example, the modulation relationship describing the controlled power output of the electrodes 702 driven by the driver 18 may be selected from the list consisting of the following: fixed relationship, constant relationship, linear relationship, non-linear relationship, logarithmic relationship, sinusoidal relationship, exponential relationship, polynomial relationship, and combinations thereof. The relationship may be directly proportional or inversely proportional depending on the system configuration and may be determinable using the explanations and equations contained herein. The controlled power output may be considered as instantaneous power and / or average power and / or peak power. The modulation may be achieved, as a non-limiting example, through the control of the driver 18. The term "modulation" is used herein to indicate the alteration of an otherwise consistent output, waveform, or signal. As used herein, "modulating" a waveform is comparable to "enveloping" a waveform, and "modulation envelope" is comparable to "envelope." Alternatively, no modulation may be used to essentially envelope a waveform, including a pulsatile waveform.

[0097] As a non-limiting example, when creating a corneal flap incision, the duty cycle D c is the effective incision width y a This can be modulated by utilizing a composite relationship that represents the velocity profile v t Multiplied by target tissue x c is modeled as a circular chord length of radius R that varies as a function of distance into the cavity (i.e., the height of the circular cap), [ka] This can result in R and v t, max , may be normalized using a nominal value for , to provide a generic envelope function.

[0098] Alternatively, the voltage required for evaporation, U, is [ka] and at least a component of the modulation relationship for the electrode voltage V provided by the driver 18 to the electrode 702 is [ka] It should be noted that the preceding example involves an exponential relationship, at least in part, because the radical root is the inverse function of the power.

[0099] Alternatively, the energy per cycle provided by the driver 18 to the electrodes 702 may be determined, at least in part, by v t and / or at least in part, depends on the value of the effective incision width y a The energy per cycle may be configured to deliver an energy per cycle that may depend on the value of

[0100] Alternatively, the duty cycle provided by the driver 18 to the electrodes 702 may be determined, at least in part, by v t and / or at least in part, depends on the value of the effective incision width y a The pulse width may be configured to deliver a duty cycle that may depend on the value of

[0101] Alternatively, the voltage provided to the electrode 702 by the driver 18 may be determined, at least in part, by v t and / or at least in part, depends on the value of the effective incision width y a The input may be configured to deliver a voltage that may depend on the value of

[0102] Alternatively, the current limit provided by the driver 18 to the electrode 702 may be determined, at least in part, by v t and / or at least in part, depends on the value of the effective incision width y a The current limit may be configured to deliver a current that may depend on the value of

[0103] Alternatively, the power limit or set point provided by the driver 18 to the electrode 702 may be determined, at least in part, by v tand / or at least in part, depends on the value of the effective incision width y a The power limit or set point may be configured to deliver a power limit or set point that may depend on the value of

[0104] Alternatively, the PRF provided by the driver 18 to the electrode 702 may be, at least in part, t and / or at least in part, depends on the value of the effective incision width y a The PRF may be configured to deliver a PRF that may depend on the value of

[0105] Alternatively, v t is determined, at least in part, by the effective incision width y a and / or x c may depend on [ka] It is.

[0106] Alternatively, the tensioned electrode assembly 5 may be tensioned by tensioning element 700 to 300 mN and moved along direction 12 at 1,000 mm s with the initial electrode location between 2 mm and 4 mm from the side closest to the target tissue to be incised (i.e., the electrode's nearest point along its axis of motion). -2 With a constant acceleration of ~200 mm s -1 For the cutout portion of the electrode 702, which is translated at a maximum rate of [ka] As may be useful when made of ∼99.99% pure tungsten wire, the voltage provided by driver 18 may be configured to deliver a maximum peak-to-peak bipolar nominally sinusoidal voltage of ∼600V (with amplitudes of both ∼+300V and ∼−300V relative to nominal neutral) with a PRF (or “carrier frequency”) of ∼1 MHz that ramps linearly from ∼0V to maximum amplitude for the initial ∼50 μs of translation and ramps back to ∼0V for the final ∼50 μs of translation.

[0107] In a further alternative embodiment, the duty cycle provided by the driver 18 may be configured to deliver a duty cycle that ramps up from 0% to a maximum amplitude between 70% and 100% for the initial 50 μs of translation and ramps down back to 0% for the final 10 μs of translation. The duty cycle may be generated utilizing a modulation frequency such as a square wave gating function. The square wave gating function may be configured to have variable "on" and / or "off" times. The relationship of the variable "on" and / or "off" times may be as may be described elsewhere herein with respect to relationships for describing controlled power output of the electrodes.

[0108] In a further alternative embodiment, the duty cycle provided by driver 18 is determined, at least in part, by v t The electrode speed may be configured to deliver a duty cycle that depends on the value of v t =0mm s -1 ) to its maximum value, the duty cycle may be gradually increased from ∼0% to a maximum amplitude between ∼70% and ∼100%, and the duty cycle is then reduced to ∼0% as the electrode speed is reduced back to stationary.

[0109] In a further alternative embodiment, the maximum power output provided by driver 18 is determined, at least in part, by v t The pulse width may be configured to deliver a maximum power output that depends on the value of , which may ramp up from ∼0% to a maximum amplitude between ∼70% and ∼100% while the electrode speed is increased from stationary to its maximum value, and the maximum power output is then reduced to ∼0% as the electrode speed is reduced back to stationary.

[0110] In a further alternative embodiment, the voltage provided by driver 18 is determined, at least in part, by v tThe duty cycle may be configured to deliver a voltage that depends on the value of , which may ramp up from ∼0% to a maximum amplitude between ∼70% and ∼100% while the electrode speed is increased from stationary to its maximum value, and the duty cycle is then reduced to ∼0% as the electrode speed is reduced back to stationary.

[0111] FIG. 7 illustrates a method of dissecting tissue. Flowchart 100 includes steps 102-122, which may be completed sequentially or in any suitable order. In step 102, an eye is selected for treatment. Step 104 involves activating the system, and step 106 involves positioning the probe on the tissue to be treated. Step 108 involves activating the vacuum system and securing the tissue relative to the probe (such as via the vacuum system described above). Step 110 involves positioning the contact plate at a first location on the tissue. Step 112 involves power being applied to the electrodes. Step 114 involves translating (or "moving" or "actuating") the electrodes in a first direction (along axis of motion 12, the "+x-direction", etc.). Step 116 involves disconnecting power to the electrodes. Step 118 involves removing the vacuum fixation, freeing the tissue and detaching the eye being treated. Step 120 involves disengaging the electrode from the just-cut tissue. Step 122 involves deactivating the system and disengaging it from the eye. The thin electrode may be allowed to break as the system is disengaged from the patient. Alternatively, the electrode may be translated in a second direction nominally opposite to the first direction. Alternatively, steps 108 and 110 may be swapped and power may be applied to the electrode once in contact with tissue 2. Alternatively, steps 116-120 may be eliminated to produce an explant. Alternatively, steps 116 and 118 may be eliminated only if there is a low risk of collateral damage due to tissue heating while the actuator is changing direction. Alternatively, step 116 may involve a tapered reduction in power to the electrode and step 112 may involve a tapered increase in power to the electrode as described elsewhere herein.

[0112] 7 illustrates a method of dissecting tissue according to some embodiments, but one of ordinary skill in the art will recognize that many adaptations and variations may be made in accordance with this disclosure, for example, steps may be performed in any suitable order, some of the steps may be repeated, some of the steps may be omitted, combinations thereof.

[0113] In some embodiments, a processor as described herein is configured with instructions to perform one or more of the steps of the method of FIG.

[0114] 8A-8D are directed to details according to an embodiment of the present disclosure, where the stretched electrode assembly 5 is shown in an orthogonal view to that of FIGS. 4-6, such that the axis of motion 12 may be in or out of the plane of the view here, while the axis of motion 14 may be vertical, and the steps of FIG. 7 may be followed. FIG. 8A shows that the contact plate 804 may be configured to be in a central portion of the support 802 and move relative to the support 802 along the axis of motion 14. The contact surface 806 of the contact plate 804 may be generally planar and generally parallel to the cut portion of the electrode 702. The electrode 702 is initially shown in this view as being behind the cornea. The contact element 808 may be placed on the contact surface 806 to create a sterile disposable for use only during a single procedure. The contact element 808 may nominally conform to at least a portion of the contact surface 806. The portion of the contact surface 806 to which the contact element 808 conforms may be the central portion. The suction element 810 may be configured to contact the eye containing the tissue 2 in an area near the outer cornea and / or corneoscleral limbus 838 as shown, to immobilize and stabilize the cornea 843 (not shown in this figure). Alternatively, the suction element 810 may be contacted at least to the side of the cornea 843 to better stabilize the tissue 2 against the incision of the electrode 702. The cornea 843 may comprise an anterior corneal surface 842 and a posterior corneal surface 844. In this case, the target tissue 2 is considered to be stromal tissue within the cornea 843 and may be contained between the anterior corneal surface 842 and the posterior corneal surface 844. An intraocular lens 840 is shown for orientation purposes and may be a natural or prosthetic lens. In this embodiment, the contact element contacts the apex of the anterior corneal surface 842 of the cornea 843. The tensioned electrode assembly 5 may include, as shown, arms 710 and 712, and an electrode 702. The configuration of this figure may represent steps 102, 104, and 106 of FIG.

[0115] 8B shows the system of FIG. 8A where contact plate 804, and therefore contact element 808, may be said to be moved farther along axis of motion 14 to flatten cornea 843 and tissue 2 therein. Electrode 702 may be caused to incise tissue 2 by traversing a path along axis of motion 12, as described elsewhere herein, creating incision 45 and thereby scaffold 43 (not shown in this figure). The configuration of this figure may represent steps 108, 110, 112, and 114 of FIG. 7.

[0116] Figure 8C shows the system of Figure 8B in a different orientation, as supported by axes of motion 12 and 14, such that incision 45 is seen to progress through tissue 2 as electrode 702 is translated along axis of motion 12 (shown proceeding from left to right in this view). Actuation of electrode 702 may be performed in its final position, as may be the case when creating a flap incision.

[0117] FIG. 8D shows the system of FIGS. 8A-8C, where the contact plate 804, and therefore the contact element 808, may be said to have been moved along the axis of motion 14 to come to rest just on the apex of the corneal surface 842, as in FIG. 8A. The figure now shows the incision 45, which may form the surface for the scaffold 43 (not shown). The surface shape of the scaffold 43 so generated may be nominally characterized as approximately that of the anterior corneal surface 842. Alternatively, the surface shape of the central region of the scaffold 43 (not shown) so generated may be characterized as an average value of at least a portion of the surface shapes of the anterior corneal surface 842 and the contact surface 806 (or the contact element 808). The average may nominally be an arithmetic mean, a geometric mean, a harmonic mean, a weighted mean, or a combination thereof. The configuration of this figure may represent steps 116, 118, 120, and 122 of FIG. 7.

[0118] FIG. 9 describes a method similar to that of FIG. 7 with additional steps 202-212, where step 116 may be performed optionally to allow the electrodes to cut during step 202. That is, alternatively, steps 116 and 118 may be eliminated only if there is a low risk of collateral damage due to tissue heating while the actuator is changing direction and / or strain on the unpowered electrodes may cause the electrodes to fail due to the change in position of the contact plates. Step 202 involves positioning the contact plates in a second position, which may be a translation of the entire element or a translation of at least a portion of the element. The translation of at least a portion of the element may be utilized to generate a non-planar contact plate surface and provide the desired corneal deformation, as will be described with respect to FIGS. 11A and 11B. Alternatively, certain contact plates may be swapped in step 202 to provide the desired corneal deformation. The corneal reshaping may be intended to generate a surface that defines at least a portion of the corneal fragment, such as the base 43, to achieve at least a portion of the desired three-dimensional tissue ablation profile. The corneal fragment may then be removed to cause a refractive change in the cornea 843 of the patient's eye. Step 204 may be optionally performed if step 202 is removed, but may otherwise be similar to step 112. Step 206 involves translating the electrode in a second direction, which may nominally be opposite to the first direction. Step 208 involves disengaging the electrode from the tissue, as may occur if the translation of step 206 brings the electrode outside the tissue 2. Step 210 involves removing power to the electrode and may be similar to step 116 of FIG. 7. Step 212 involves removing the vacuum fixation, freeing the tissue, and disengaging the eye being treated, which may be similar to step 118 of FIG. 7. Step 122, similar to step 122 of FIG. 7, involves deactivating the system and detaching it from the eye.

[0119] 9 illustrates a method of dissecting tissue according to some embodiments, but one of ordinary skill in the art will recognize that many adaptations and variations may be made in accordance with this disclosure. For example, steps may be performed in any suitable order, some of the steps may be repeated, some of the steps may be omitted, combinations thereof.

[0120] In some embodiments, a processor as described herein is configured with instructions to perform one or more of the steps of the method of FIG.

[0121] 10A-10F are directed to a system similar to that of FIG. 8A-8D, in which the shape of the contact surface 806 may be configured as other than planar, and is shown as convex, and further configured such that a corneal piece (e.g., corneal piece 820) may be incised into the (stromal) tissue 2 of the cornea 843. The contact surface 806 may be considered a correction surface. The difference between the first and second incision profiles may correspond to the shape of the corneal piece of tissue to be removed from the cornea to treat (or "correct") the refractive error of the eye. The difference between the first and second incision profiles may correspond to a three-dimensional tissue ablation profile. The union of the first and second incision profiles may correspond to a three-dimensional tissue ablation profile.

[0122] Figure 10A shows a system configured similarly to that of Figure 8A with the addition of a curved surface 806 on the contact plate 804. Similarly, a contact element 806 is placed on the curved contact surface 806 and nominally matches the curvature. The configuration of this figure may represent steps 102-108 of Figures 7 and 9.

[0123] Figure 10B shows the system of Figure 10A where contact plate 804, and therefore contact element 808, has been moved farther along axis of motion 14 and may be said to be in contact with cornea 843 and tissue 2 therein. Unlike the configuration of Figures 8A-8C, in this configuration the cornea is not necessarily flattened, but is compressed differently to at least partially conform to the curvature (or "shape", in cases where curvature alone may not be sufficient to adequately describe contact surface 806) of contact surface 806 to produce incision 46. The configuration of this figure may represent steps 110-112 of Figures 7 and 9.

[0124] Figure 10C shows the system of the previous Figure 10X in a different orientation, as supported by axes of motion 12 and 14, such that incision 45 is seen to progress through tissue 2 (shown in this view proceeding from left to right) as electrode 702 is translated along axis of motion 12. Actuation of electrode 702 may be performed in its final position, as may be the case when creating a flap incision.

[0125] 10D shows the system of FIG. 10X above, with the contact plate 804 translated forward, and the incisions 46 now shown. Such incisions 46 may form the surface of the foundation 44 (not shown). The surface shape of the foundation 44 so produced may be characterized as the average value of the surface shapes of the anterior corneal surface 842 and the contact surface 806 (or contact element 808). The average may nominally be an arithmetic mean, a geometric mean, a harmonic mean, a weighted mean, or a combination thereof.

[0126] FIG 10E shows the system of the previous FIG 10X where a second incision, incision 45, may now be made. The configuration of this figure may represent steps 202-206 of FIG 9. Alternatively, incision 45 may be made by swapping contact plate 804 or a portion thereof to provide a different surface shape for incision 45. A flat contact surface may be used for at least one of the incisions.

[0127] FIG 10F shows an eye treated with the system of the previous FIG 10X, where a corneal strip 820 has been incised into the (stromal) tissue 2 of the cornea 843 and is bounded by a surface created by incisions 45, 46. Incisions 45, 46 may also form incisions 47 when electrodes are cut across the entire cornea rather than to create a pocket in the cornea. This configuration may represent the result of completing the remaining steps of FIG 9. The shape of the surface created via incisions 45, 46 may be selected to affect the refractive correction to the cornea 843 of the patient's eye. The refractive correction may be defined, at least in part, by diagnostic measurements such as keratometry, ocular aberrometry, wavefront aberrometry, corneal topography, and combinations thereof, and the nominal shape of the corneal strip may be defined to optically balance (or correct) the measured aberrations, as described in Sekundo W. Small Incision Lenticule Extraction (SMILE) Principles, Techniques, Complication Management, and Future Concepts. 2015. Springer Cham Heidelberg and associated citations therein.

[0128] In some embodiments, for the cornea, the approximate tissue profile for the tissue to be removed may be expressed as follows:

[0129] T(x,y)~=W(x,y) / (n-1), where T is the thickness in microns, W is the wavefront error in microns, n is the refractive index of the cornea, and x and y are coordinate bases corresponding to a plane such as the pupil or a plane near the apex of the cornea. The wavefront error can be expressed in a number of ways, for example, using elevation angle in microns or individual Zernike coefficients.

[0130] Other approaches may also be used to determine the thickness profile of the tissue to be removed, for example, with reference to the SMILE procedure, as would be known to one of skill in the art.

[0131] 11A and 11B are directed to a piecewise adjustable contact plate 804 for reshaping the cornea to generate corneal grafts or other therapeutic incisions. The adjustable contact plate 804 can be operably coupled to a controller and configured to shape the cornea and provide refractive correction, for example, with reference to small incision corneal graft extraction as described herein. FIG. 11A depicts the piecewise adjustable contact plate 804, comprised of a sub-plate (or equivalently, "element") 8061, which may constitute a contact surface 806, both housed within a housing 8042 and mounted to a base 8044. FIG. 11B depicts the same contact plate 804 in a cross-sectional view to expose an actuator 8100, which is operably coupled to the sub-plate 8061 within the housing 8042. In this embodiment, each of the subplates 8061 may be affixed to an actuator 8100, as shown and described with respect to the system of FIG. 6, allowing each subplate 8061 to be individually actuated using additional actuators and associated monitoring and control subsystems (the connections are not shown in this figure). As a non-limiting example, the subplates 8061 may be glued or soldered to the actuator 8100 using epoxy. The actuator 8100 may be selected from the group consisting of a piezoelectric actuator, a motor, a pneumatic actuator, a fluid actuator, and combinations thereof. As shown in the exemplary embodiment, the subelements 8062 may be constructed using a material selected from the group consisting of glass, ceramic, quartz, silicon, metal, polymer, and combinations thereof. Such subplates 8061 may be actuated along an axis of motion (e.g., axis of motion 14).Such sub-plates 8061 may be translated (or "displaced") to form piecewise contact surfaces 806 with freeform profiles (or "shapes" or "surface profiles") to address optical aberrations, including higher order aberrations such as defocus, radial distortion, sphere, spherical aberration, cylinder, cylindrical aberration, astigmatism, coma, and trefoil, in prescribing surface shape precision for a corneal fragment to be removed from tissue 2 within cornea 843, generating contact surfaces 806 with discrete, but arbitrarily, addressable profiles for use in generating incisions 45 and / or incisions 46. Such sub-plates 8061 are configured to be nominally rectangular as shown, but need not be, and other geometries are considered within the scope of the present disclosure. Contact elements 808 (not shown) are located on the distal surface of the contact plate 804 and may provide a clean and / or sterile surface for contact with tissue 2 and may be configured as a thin, conformal peelable and adhereable sterile barrier, which may also be disposable, as described elsewhere herein. Rather than utilizing step 202 of FIG. 9 to reposition the contact plate 804, the present embodiment may allow step 202 to be modified to reconfigure the contact plate to a second configuration prior to creating another incision. The number of actuators 8100 may be determined by the spatial resolution requirements and / or surface form accuracy tolerances of a given prescription. As a non-limiting example, there may be an array 10 of square cross-sectionally shaped actuators 8100, or there may be an array 14 of such actuators 8100, or there may be an array 28 of such actuators 8100, which when configured to be squarely packed within a nominally 12 mm diameter disc-shaped contact surface, respectively, of ∼2.0 mm per actuator 8100. 2 , ~1.44mm 2 , and ~0.80 mm 2Alternatively, a more regular array, such as a 4×4 square array, may be used, resulting in 16 actuators 8100. When such a regular array of 16 square cross-sectional shaped actuators 8100 is positioned concentrically with a nominally 12 mm disc-shaped contact surface, the area per actuator is ∼9 mm 2 , but the corners of the array may be outside the 12 mm disk boundary. Similarly, a 10x10 square array would be ∼1.44 mm 2 This can result in an area per actuator of

[0132] Alternatively, the corrective portions of the customized contact plate 804 and / or contact surface 806 may be machined to configure a surface profile for use in creating the incision 45 and / or the incision 46 to address higher order aberrations in prescribing surface shape accuracy for the corneal piece to be removed from the tissue 2 within the cornea 843. Alternatively, such customized contact plate 804 and / or contact surface 806 may be used individually in creating the incision 45 and / or the incision 46. Alternatively, a first customized contact plate 804 and / or contact surface 806 may be used in creating the incision 45 and a second customized contact plate 804 and / or contact surface 806 may be used in creating the incision 46, and the first and second customized contact plates 804 and / or contact surfaces 806 may be configured with different surface profiles. 9 to reposition the contact plate 804, the present embodiment may allow that step 202 to be modified to be replaced (or "swapped") with a second contact plate prior to creating another incision. The means of fabricating such customized contact plate 804 and / or contact surface 806 may be selected from the group consisting of additive manufacturing, injection molding, machining, and combinations thereof.

[0133] In some embodiments, the optical prescription may comprise one or more of the following: surface curvature, power in diopters, material properties, refractive index, ocular wavefront measurements, or thickness. In some embodiments, the surface form accuracy of the optical system may be defined as the perturbation of the optical surface from the optical prescription. Low frequency errors are typically defined as irregularities, deviation fringes, or flatness, and may tend to transfer light from the center of the Airy disk pattern into the first few diffractive rings. This effect may reduce the magnitude of the point spread function without broadening it, and thus reduce the Strehl ratio. Mid-frequency errors (or small angle scatter), defined using a slope or (PSD) requirement, tend to broaden or smear the point spread function (PSF), and may reduce contrast. Both low and mid-frequency errors may degrade optical system performance. However, some surface form accuracy imperfections may be omitted from the surface form accuracy specification, as may be the case for power and occasional astigmatism. An optical system may allow individual optics to be focused, de-centered, or tilted to compensate for specific aberrations. Surface accuracy and surface form precision are terms often used to capture both areas. To avoid ambiguity, one may use microns as the unit value in the specifications.

[0134] 12A and 12B are directed to the creation of a disk-shaped corneal strip. FIG. 12A shows a corneal strip 820 consisting of an anterior surface 451, which may be created by incision 45, via step 114 of FIGS. 7 and 9, and a posterior surface 461, which may be created by incision 46, via step 118 of FIGS. 7 and 9. A hinge 1020 may be created via step 202 of FIG. 9, which is the translation of the contact plate to a second position between the creation of incisions 46 and 45. In this figure, the corneal strip may appear to be a flat disk as shown, if it is spread out on a flat surface, as shown. FIG. 12B shows a cross-sectional view of the same corneal strip 820 of FIG. 12A. In this embodiment, a nominally planar contact plate may be positioned at a first position (or "depth" or "location") to create incision 46 and then translated to a second, more anterior (or "proximal") position to create incision 45. In the configuration of this embodiment, cross-sectional shape 1010 may be nominally rectangular and faces 451 and 461 may be nominally parallel. Alternatively, incision 45 may be created at a position posterior (or "distal") to that of incision 46 by appropriate translation of the contact plate.

[0135] 13 is directed to a plano-convex type corneal strip similar to that of FIG. 12B, according to an embodiment of the present disclosure. Here, corneal strip 820 comprises an anterior surface 451, which may be created by incision 45, and a posterior surface 461, which may be created by incision 46. The contact plate, or elements of the contact plate consisting of multiple translatable elements, may be configured to produce a non-planar type surface for surface 451. The configuration of this embodiment may be utilized to create a plano-convex type corneal strip, as shown.

[0136] 14 is directed to a meniscus shaped corneal strip similar to that of FIG. 13, according to an embodiment of the present disclosure. Here, the corneal strip 820 comprises an anterior surface 451, which may be created by incision 45, and a posterior surface 461, which may be created by incision 46. The contact plate, or elements of the contact plate consisting of multiple translatable elements, may be configured to produce non-planar type surfaces for both surfaces 451 and 461. The configuration of this embodiment may be utilized to create a meniscus type corneal strip, as shown.

[0137] 15 is directed to a hybrid type corneal strip similar to that of FIG. 14, according to an embodiment of the present disclosure. Here, corneal strip 820 comprises an anterior surface 451, which may be created by incision 45, and a posterior surface 461, which may be created by incision 46. The contact plate, or elements of the contact plate consisting of multiple translatable elements, may be configured to produce non-planar type surfaces for both surfaces 451 and 461. The configuration of this embodiment may be utilized to create a meniscus type corneal strip, as shown.

[0138] 16A and 16B are directed to histological images of incisions in a porcine cornea generated in accordance with an embodiment of the present disclosure. FIG. 16A shows image 900, a conventional sagittal section (H&E stained) histological microscope image of a porcine cornea that was incised in a fresh state (≦2 days after collection and stored at ∼2° C.) and subsequently fixed in a 4% paraformaldehyde solution. The incision system was configured with the following: PRF ∼1 MHz, V ∼±250 V, sinusoidal waveform, P rms ~15W;v t, max ~400mm·s -1 ;~2,000mm·s -2 constant acceleration; [ka] , L~10 mm, ~99.99% pure tungsten wire electrode; T~290 mN; ~35 μm contact plate (flat) rearward displacement between incisions 45 and 46, and ~-500 mmHg vacuum gauge pressure for suction element 810, as measured by vacuum sensor 854. Electrode assembly translation was accomplished using a M-664.164 piezoelectric motor actuator (PI, Karlsruhe, Germany). Target tissue 2 is corneal stromal tissue. Incision 45 was separated to expose surfaces 451 and 452. Incision 46 was left intact with corneal strip 820 in place. Damage may be visible as darker bands along incisions 45 and 46 and may be in the range of ~3 μm. Figure 16B shows an image 902 similar to that of Figure 16A, but at a higher magnification and with a different spacing between incisions 45 and 46, using a rear contact plate translation of -50 μm. Again, a thin damage zone is evident.

[0139] 17 is directed to a plot 910 displaying an example electrode voltage versus time waveform 912, constituting features according to an embodiment of the present disclosure. The waveform 912 comprises individual cycles 914. Bursts 916 are made up of pulses (cycles 914) and are constrained by a modulation envelope 918. The modulation envelope 918 may be configured to be a combination of relationships described elsewhere herein, including pulsation, duty cycle, and modulation (e.g., titration) relationships. Although shown here at the level of pulses and bursts for clarity, the entire dissection waveform may be similarly configured.

[0140] Figure 18 shows the equivalent sensitivity and t shWe focus on image 960, a 576 pixel by 464 pixel frame, such as might be acquired using a high-speed digital camera, such as an AOS M-VIT4000 (AOS Technologies, Daettwil, Switzerland), when configured to operate with a shutter speed (or "integration time") of .about.250 μs. In this figure, multiple vapor cavities 635 along image element 962 may indicate an intermittent process, similar to that of FIG. 6-10E, i.e., v t, max ~400mm·s -1 ;~2,000mm·s -2 constant acceleration; [ka] 17. For a dissection system configured as: L ∼ 10 mm, ∼ ≥ 99.99% pure tungsten wire electrodes; T ∼ 280 mN, and a vacuum gauge pressure of ∼ -640 mmHg for the suction element 810, as measured using vacuum sensor 854, nominally utilizing the waveform of FIG. t *t sh →~13μm and PRF*t sh → may correspond to approximately one diametric electrode translation for .about.250 cycles of a .about.1 MHz waveform. Vapor cavities 635 may be visible along image element 962 as electrode 702 (located in image element 962, but otherwise not visible in this view) is actuated and translates along axis of motion 12 in direction 121 to create an incision in cornea 843. Vapor cavities 635 may comprise regions from which light is emitted in association with the formation of plasma, the light may have a wavelength that is a function of the plasma temperature and may be in the range of about 400 nm to about 750 nm.

[0141] According to embodiments of the present disclosure, technique dependency of scleral incisions may be reduced by semi-automating flap creation using plasma-induced cutting tools, which limits tissue damage and provides predictable, accurate, and precise incisions in the sclera and / or cornea, including the sclerocorneal limbus. According to embodiments of the present disclosure, pockets in the sclera and / or cornea, including the sclerocorneal limbus, may be created rather than the traditionally used flaps. Further embodiments may provide incisions in other tissues, such as those listed in FIG. 1A. As non-limiting examples, plasma-induced incisions may be created in the capsule to produce a capsulotomy, in the lens to produce lens fragments or to simplify lens fragmentation and / or lens removal, in the retina to produce a pocket or flap, in the TM to improve drainage and / or reduce IOP, and in the iris to produce an iridotomy.

[0142] A flap may be described as an incision resulting in a "flap" of tissue that can be lifted and pivoted on a "hinge" to provide access to the tissue beneath. As a non-limiting example, cutting three sides of a square to a 50% depth and cutting a plane at that 50% depth just below the edge of the square in tissue may result in a half thickness flap with the fourth uncut side of the square as its hinge. The flap may be severed by completing the fourth side of an exemplary square incision.

[0143] A pocket may be described as an incision that separates a first depth (or layer) of tissue from a second depth (or layer) of a section of tissue, without necessarily creating a flap. As a further non-limiting example, cutting one side of a square to a 50% depth and cutting a plane at that 50% depth just below the edge of the tissue square may result in a half thickness pocket.

[0144] A semi-automated cutting tool may be used to provide improved incision over that of a conventional sharp-edged instrument. A plasma-induced semi-automated cutting tool may be used to provide improved incision over that of a semi-automated cutting tool configured for use with a conventional sharp-edged instrument.

[0145] A semi-automated cutting system with at least one degree of motion can be used to create 5x5mm and 4x4mm flaps instead of creating them manually. For example, a system with both 5mm wide and 4mm wide "blades" can be used to create 5x5mm and 4x4mm flaps, respectively. The electrodes may comprise wires and / or blades.

[0146] FIG. 19A shows a flap 40 in tissue 2 as seen above, and FIG. 19B shows the same flap 40 as seen from cross section AA. Flap 40 is constructed from incisions 42 and 44, which create a base 43 and form three sides of a square (as is the case in the example of FIGS. 19A-19D, but other such shapes are also considered within the scope of this disclosure). The flap may be elevated and hinged about the missing side of the square to expose the tissue underneath. Base 43 may be flat or curved. The flap may be separated by completing the fourth side of the exemplary square incision.

[0147] 19A and 19B, Fig. 19C shows a pocket 41 in tissue 2 as seen above, and Fig. 19D shows the same pocket 41 as seen from cross section AA. However, in this configuration, pocket 41 consists of incision 42, which creates base 43, but lacks incision 44. Again, base 43 may be flat or curved, but this time will depend on the longitudinal shape (or "profile") of the incision to avoid creating incision 44.

[0148] FIG. 20 is directed to a system according to an embodiment of the present disclosure configured to generate a rectangular flap or pocket such as may be useful in canaloplasty for the reduction of IOP in the treatment of glaucoma. Tissue 2 may be incised using an electrode 4, which in this exemplary embodiment is configured in a U-shape of width 6 and length 8 with a bend 10. The electrode 4 may be connected to a power RF driver 18 via a lead 20. A lead 22 may be connected to the patient and generate the electrode 24, which in turn may be part of the return path. The RF driver may produce bipolar pulses. The electrode 4 may be enclosed within a sheath 16, shown here as partially cut away for clarity. A direction of motion 12 may be used to provide lateral coverage to the incision, and a direction of motion 14 may be orthogonal to the direction of motion 12 and perpendicular to a plane described by the width 6 of the U-shape of the electrode 4, which may be used to generate a tissue flap and / or pocket. Alternatively, direction of motion 14 may be employed to create an incision nominally perpendicular to the surface of tissue 2. Width 6 may be selected to be between 1 mm and 10 mm, specifically 4 mm or 5 mm, as described above. Length 8 may be configured to traverse tissue a distance greater than width 6 but less than length 8. For example, a 4 mm x 4 mm flap may be created by configuring width 6 to be 4 mm and length 8 to be greater than 4 mm but to traverse 4 mm of tissue along direction of motion 12.

[0149] FIG. 21 is directed to a system similar to that of FIG. 20 configured to generate a flap, as viewed from the side, with the addition of a probe body 26 containing an electrode 4, a sheath 16, and an actuator 50, also oriented at an angle 30 relative to the surface of the tissue 2. The actuator 50 is operatively coupled to the electrode 4 and can move in motion directions 12 and 14 such that the electrode 4 is translated within the tissue 2 along a motion profile described by moving first in direction 32, then in direction 34, then in direction 36, which is the opposite direction of direction 34, and then in direction 38, which is the opposite direction of direction 32. This configuration can then generate a flap 40 (not explicitly shown for purposes of clarity) by generating an incision 42, then an incision 44, and a base 43. As a non-limiting example, the actuator 50, such as a motor or a voice coil, can be powered. Alternatively, the actuator 50 may comprise a series of springs and ratchets or stops and triggers to generate the described motion profile. The element electrodes 4 and / or sheath 6 and / or probe body 26 may be configured to be subsystems that engage with the actuator 50 and RF driver 18 and are discarded after use. In an alternative embodiment, the flaps may be detached by modifying the motion profile as follows: first in direction 32, then in direction 34, then in direction 38, which is the opposite direction to direction 32.

[0150] Alternatively, the system of FIG. 21 may be configured such that the actuator 50 first translates the electrode 4 in a direction nominally along the angle 30 and then retracts the electrode 4 along a second direction nominally opposite to the first direction to generate a pocket rather than a flap.

[0151] Alternatively, the second electrode may also be used to generate a second flap or pocket of a different size and / or shape than the first flap or pocket. For example, a 5mm x 5mm flap may be created first, followed by a 4mm x 4mm flap. The exemplary 4mm x 4mm flap may also be a cut-away flap.

[0152] 22A-22C are directed to details of an electrode configured according to an embodiment of the present disclosure, with electrode 4 comprising regions 300, 302 and bends 10. Nominally, the surface area may be kept constant along electrode 4. As a non-limiting example, electrode 4 may comprise a solid wire between 50 μm and 300 μm in diameter and comprise a material selected from the group consisting of tungsten, nitinol, steel, copper, stainless steel, beryllium-copper alloy, cupro-nickel alloy, and aluminum. Additionally, in alternative embodiments, the electrode may be at least partially coated with another conductive material, such as gold. Region 302 may comprise the same base structure as region 300, with the modification that it is compressed in a direction parallel to the plane of the image and stretched in an orthogonal direction. Such a configuration may maintain the surface area while providing increased strength in the aforementioned orthogonal direction for improved reliability and strength while dissecting tissue by reducing dimension 303 below dimension 301. Bend 10 may be made from either the configuration of region 300, the configuration of region 302, or made to transition between regions 300 and 302. Alternatively, regions 300 and 302 and / or bend 10 may be joined from dissimilar materials. In a further alternative embodiment, electrode 4 may be constructed from a tungsten wire with a diameter of .about.250 .mu.m, which is compressed everywhere except for region 300, which is .about.3 mm long, and dimension 301 is nominally the same as the original diameter of the wire of .about.250 .mu.m, while dimension 303 is configured to be formed to .about.400 .mu.m by said compression, while original bend 10 is centered on region 300, has a radius of .about.0.5 mm, and is made to yield a width 6 of .about.4 mm.

[0153] For purposes of clarity, the electrodes 4 have been shown thus far to be U-shaped, but need not be. The RF driver 18 may provide an alternating current to the electrodes 4. Such alternating current may be, by way of non-limiting examples, a sine wave, a square wave, a sawtooth wave, a triangular wave, or combinations thereof. The signal provided by the RF driver 18 may be configured to have a base (or "carrier") frequency between 10 kHz and 10 MHz, and may further be modulated to comprise bursts of pulses at frequencies between 100 Hz and 3 MHz to produce a duty cycle. The duty cycle may be between 0.01% and 100%. In alternative embodiments, the duty cycle may be between 60% and 80%. The peak-to-peak voltage provided by the RF driver 18 may be between 500V and 2,000V. In alternative embodiments, the peak-to-peak voltage provided by the RF driver 18 may be between 400V and 800V. In one embodiment, the RF driver 18 signal is applied to the electrode 4 in the region 300. [ka]

[0036] It may be configured to have a peak-to-peak bipolar voltage of ~800V (with amplitudes of both ~+400V and ~-400V), with a carrier frequency of ~1 MHz and a modulation frequency of ~10 kHz, as may be useful when made of 1 mm diameter tungsten wire.

[0154] FIG. 23 is directed to a system 400 configured according to an embodiment of the present disclosure. In addition to the elements associated with the previous figures, the system 400 further comprises a controller 60, a power supply 70, a user interface 80, and a coupler 52. A connection 62 connects the controller 60 and the RF driver 18 and is at least a unidirectional connection. The connection 62 may also be a bidirectional connection, with the controller 60 being able to sense and / or respond to signals from at least the RF driver 18. Such signals may be safety signals related to sensed voltage or current. In further alternative embodiments, the RF driver 18 may provide feedback to the controller 60 or use such feedback internally or share such feedback as a signal with the controller 60. Such feedback may be, for example, EMF or current feedback and may be useful in determining when the electrode 4 contacts tissue and / or the status of the plasma. Such a status may be, for example, whether the plasma is in a glow discharge steady state. Similarly, a connection 65 connects the controller 60 and the actuator 50 and is at least a unidirectional connection. The actuator 50 may consist of at least one electric motor and may further comprise a position encoder. The connection 65 may alternatively be a bidirectional connection, with signals such as position, velocity, acceleration, out-of-bounds error, etc. being shared between the controller 60 and the actuator 50. In further alternative embodiments, the actuator 50 may provide feedback to the controller 60 or use such feedback internally, and may share such feedback as a signal with the controller 60. Such feedback may be, for example, force feedback, which may be useful in determining when the electrode 4 contacts tissue or exerts excessive force on the tissue to be incised. Similarly, the connection 67 connects the controller 60 and the power supply 70, and is at least a unidirectional connection.In further alternative embodiments, the power supply 70 may provide feedback to the controller 60 or may use such feedback internally or may share such feedback as a signal with the controller 60. Such feedback may be, for example, an error signal. Such error signals may be temperature error, input voltage error, output voltage error, input current error, output current error, etc. Similarly, the connection 68 connects the controller 60 and the user interface 80 and is at least a unidirectional connection. In further alternative embodiments, the interface 80 may provide feedback to the controller 60 or may use such feedback internally or may share such feedback as a signal with the controller 60. For example, the user interface 80 may be a graphical user interface or a button that is used to signal the actuator 50 to move the electrode 4 and cut the tissue. This exemplary embodiment of the system 400 also includes a coupler 52, which may couple the electrode 4 to the actuator 50 such that the electrode 4 may be moved as described with respect to the previous figures. The coupler 52 may be constructed from an electrically insulating material and configured to electrically insulate the electrode 4 from at least one other element of the system 400. The coupler 52, and / or the sheath 16 and the electrode 4 may be spliced ​​into a subsystem that may be discarded after use. An alternative embodiment is a configuration for the coupler 52 that may be fabricated to connect both sides of the (exemplary) U-shaped electrode 4 to the actuator 50. The electrode 4 is moved by the actuator 50 at a distance of ∼200 mm·s. -1 can be translated at a rate of

[0155] 24A and 24B are directed to details involving the creation and use of complementary features in tissue 2 that may provide improved mechanical stability and better maintain, at least in part, a fixed relationship between elements of tissue 2 that may be separated from one another by incisions 45 using the systems and methods described herein, including when creating a corneal flap or other surgical refractive correction. Thus, incisions 45 may comprise a correction portion as described elsewhere herein and an additional stability portion 1108, which may comprise complementary features. Target tissue 2 may be incised along incisions 45 to create a flap 40 and foundation 44 in cornea 843, which in turn may include an anterior surface 842 and a posterior surface 844. In this example, incisions 45 may be configured to create nominally complementary feature protrusions 1110 and depressions 1112 in flap 40 and on foundation 44, respectively. Such complementary features may be configured, at least in part, to interlock and provide stability between the interface between the first and second sides of the tissue incision profile, at least in part to reduce the occurrence of the flap 40 or any other adjacent incision element dislocating ("dehiscence") from the cornea 843 during healing, and may further serve, at least in part, to block epithelial cells from entering the wound along the incision edge 1114. As shown, the angle between the corneal surface 842, whose apex is along the edge 1114, and the incision 45 may be a fairly shallow angle, such as that which may be created when using a conventional microkeratome. In this example, the cornea 843 of the eye EYE contains the target tissue 2, although other anatomical locations and configurations are also considered within the scope of this disclosure. Although shown as such in this figure, the flap 40 need not be completely separated from the target tissue 2, and may comprise a pocket or hinge portion, as described elsewhere herein. Once completely separated from the cornea 843, the flap 40 may be considered a "cap." The cap may be particularly well suited for use in corneal transplant procedures. The pocket incision may also be configured to utilize such complementary features for similar purposes.As described elsewhere herein, the incision system may be configured to generate nominally complementary features protrusions 1110 and depressions 1112 via the surface profile of the contact plate. Alternatively, such features may be generated using suction elements 810 to deform the target tissue prior to and / or during the creation of the incision. Alternatively, generating an incision with a border (equivalently, a "border", "circumference", "perimeter") with a border 1114 whose angle to the surface of the incised tissue is as steep as possible (or "orthogonal", "normal") may provide improved stability. This may be achieved by limiting the distance between the stability portion 1108 and the incision border 1114. This may be optimized by overlapping the stability portion 1108 and the incision border 1114. The incision depth may be chosen such that the incision will not disrupt Bowman's membrane anteriorly or Descemet's membrane posteriorly. An incision depth of 20%-80% of the corneal thickness may generally be sufficient to provide a safety margin. An incision profile may be considered to be the resulting surface profile of tissue in its relaxed state after incision. An incision profile that separates (or "excises" or "removes") a volume of tissue may correspond to an "ablation" profile, as described elsewhere herein. Complementary features may be configured such that a feature on one surface is received, at least in part, within a feature on an opposing surface. Alternatively, complementary features may be intended to receive an implant, such as, but not limited to, a prosthesis, an intracorneal lens, or a drug delivery device.

[0156] 25 is directed to a further embodiment of the present disclosure for creating and using complementary features in tissue 2 similar to those of FIGS. 24A and 24B, including the addition of a cutting element 1120 to incision 45, modified to provide a steeper angle between corneal surface 842 and incision 45. The cutting element 1120 may further reduce epithelial wound penetration, improve the mechanical stability of incision 45, and serve, at least in part, to maintain the relative position of the incised target tissue.

[0157] 26 is directed to an embodiment, where either the suction element 810 and / or the contact element 804 may be further configured to include a correction portion 819 as described elsewhere herein and an additional stability portion 1108. In the case of a corneal incision, the correction portion 819 may be refractive correction as described elsewhere herein. In the case of a corneal incision, the stability portion 1108 may be further configured to be outside of the optical aperture 1150 (shown in subsequent figures) and may be configured to generate nominally complementary feature protrusions 1110 and depressions 1112, generated by at least a portion (or "region") of the contact element 804 and / or by at least a portion (or "region") of the suction element 810. The correction portion 819 may be within the optical aperture 1150. The refractive correction portion 819 may be configured to produce a corneal strip 820, as a non-limiting example. A tensioned electrode 702 may be supported by arms 710 and 712, bounded by incision 47, and creating at least incision 45 containing correction portion 819, shown as corneal strip 820, and stability portion 1108, extending beyond optical aperture 1150 (known as the "optically clear aperture" or optical zone for refractive correction). The electrode is translated along axis of motion 12 in direction 34 to location 1121 to create incision boundary 1114, including hinge 1020, and then translated in direction 36 to at least location 1122 to incise at least a portion of correction portion 819 and stability portion 1108. Translation along direction 36 or power to the electrode may be interrupted at location 1122 to preclude re-cutting of redundant portions of the incision, such as the corneal incision shown. A suction channel 1210 may be utilized to anchor to the target tissue, as described elsewhere herein. Regions 1209 and 1211, which may form at least a portion of surface 1200, may be configured to form a nominally flat surface 1200 or to be at different heights. For example, region 1211 may be made to protrude from contact surface 1200.

[0158] Tissue shaping with the contact elements can be performed in many ways, and the contact elements can be configured in many ways, for example, with protrusions or channels and combinations thereof, as described herein. Tissue shaping while the incision is being made allows the incision to be approximately linear while the tissue is shaped with the constraining configuration. When the contact elements are removed, the tissue can relax to a freestanding configuration such that the tissue structure imparted into the tissue with the contact elements appears along the incision profile 45 in the freestanding configuration when the incision is made. This tissue shaping with the contact elements allows any suitable shape, for example, a three-dimensional shape, to be formed with a substantially linear incision profile when the tissue is incised with the electrode. In some embodiments, the incision profile 45 comprises a two-dimensional linear incision profile when the tissue is engaged with the contact elements, and the one or more complementary features comprise a three-dimensional complementary surface profile, for example, protrusions 1110 and complementary indentations 1112, when the tissue relaxes to the freestanding configuration.

[0159] 27A-27C are directed to an embodiment of a suction element 810 that may be used to both stabilize the tissue 2 against the contact plate 804 (as described with respect to FIGS. 6-11) and / or the electrode 4 (as described with respect to FIGS. 6-11) and to impart complementary characteristics to the incision 45 by drawing at least a portion of the tissue 2 into at least a portion of the channel 1210 (here shown as an annular ring) on ​​the suction contact surface 1200. The suction element 810 may be configured to support a nominally open annular ring for the channel 1210 as shown, or alternatively, by any other applicable construct to achieve fixation to the eye, such as a single open pocket, or multiple open pockets, or multiple such channels 1210, and combinations thereof. The suction element 810 may be operably coupled to a vacuum pump 850 via a vacuum line 870, shown here protruding from the proximal surface 1202 and providing negative pressure within the suction element 810 prior to and / or during the creation of the incision to draw elements of the target tissue 2 at least partially into the open space of the channel 1210 (as described with respect to FIG. 6 ). A second such channel, channel 1212, is included within this exemplary embodiment and may be utilized to evacuate fluid from the target tissue 2, but is not required to practice the present disclosure. The suction line 870 may be configured to provide the same vacuum circuit to channels 1210 and 1212, or to address them individually, as shown in the cross-sectional view of FIG. 27C . This embodiment may be configured to engage tissue 2 immediately adjacent or near the location of incision 45 using only channel 1210 to produce the results shown in FIGS. 24A-25, where protrusion 1110 and indentation 1112 are shown as nominally continuous. In the case of a corneal incision, channel 1210 may engage the corneal surface inside the electrode path as opposed to outside the electrode path on the sclera and / or limbus, as described above. Thus, tissue captured by channel 1210 may be incised by electrode 4 as part of incision 45, which may include compensation portion 819 and stability portion 1108.Region 1209 may reside between the central opening of suction element 810 and channel 1210. Region 1211 may reside between channels 1210 and 1212. The width (in this example, radial) of channel 1210 may be configured to be between 50 μm and 500 μm such that the correlation result width of complementary feature protrusions 1110 and depressions 1112 may be between 30 μm and 500 μm. Similarly, the depth of channel 1210 may be configured to be between 50 μm and 500 μm such that the correlation result height of protrusions 1110 and depth of depressions 1112 may be between 30 μm and 450 μm. Regions 1209 and 1211 may be configured to deviate from each other's height and / or that of surface 1200 by between ±30 μm and ±200 μm. The vacuum pressure used to achieve such a result may be between -100mmHg and -600mmHg.

[0160] 28A-28B are directed to a further embodiment of the suction element 810, similar to that of FIGS. 27A-27C, with the addition of a channel 1214 that is not configured to provide suction to the tissue 2. Instead, the channel 1214 may be located adjacent to or near the channel 1210. While shown in this exemplary embodiment as located radially beyond the channels 1210 and 1212, the channel 1214 may alternatively be located between the channels 1210 and 1212. The width and / or depth of the channel 1214 may be configured to be between 50 μm and 500 μm, such that when a vacuum gauge pressure of between ∼−100 mmHg and ∼−600 mmHg is used to provide suction to at least one of the channels 1210 and 1212, the correlated resultant width and / or depth / height of the protrusions 1110 and the recesses 1112 may be between ∼30 μm and ∼450 μm. Channels 1210 and 1212, as well as 1214, may be separated (in this example, radially) by between .about.200 μm and .about.1,000 μm. Regions 1209, 1211, and 1213 may be configured to deviate from each other and / or from that of otherwise planar surface 1200 by between .about.±.30 μm and .about.±.200 μm. Although shown as nominally regular, annular channels 1210, 1212, and 1214 need not be regular and may be configured with varying widths and / or depths.

[0161] FIG. 29 is directed to a further embodiment similar to that of FIGS. 27A-28B, with the modification that channels 1210 and 1214 are not configured as regular annular channels. In this example, channels 1210 and 1212 comprise a plurality of openings 1220 and 1222, respectively. Such a configuration may result in a plurality of corresponding protrusions 1110 and recesses 1112 for channels 1210 and 1212, and a nominally continuous protrusion 1110 and recess 1112 corresponding to channel 1214. Openings 1220 and 1222 may be configured to utilize widths between 50 μm and 500 μm, and lengths between 50 μm and 3,000 μm, with a separation (in this example, radial) between 200 μm and 1,000 μm. Additionally, suction line 870 is shown not to protrude beyond proximal surface 1202.

[0162] FIG. 30 illustrates an embodiment in which the target tissue 2 may be incised along the axis of motion 12 by the stretched electrode 702, supported by the arms 710 and 712, via the incisions 45 and 46, which may generate the flap 40, containing the correction portion (as described with respect to FIG. 19A). The corneal strip 820 is shown bounded by the incision 47 and extending beyond the visual aperture 1150 (known as the "optically clear aperture"), and the stability portion 1108 is shown with a protrusion 1110. The flap 40 may be configured with a boundary 1114, which includes the hinge 1020, and may be incised along the axis of motion 12 with the directions 34 and 36, as described elsewhere herein. Although not shown for clarity, it should be understood that a complementary feature for the stability portion 1108 of the incision may be present beneath the flap incision, as described herein.

[0163] 31A-31C are directed to alternative embodiments of the present disclosure similar to those of FIG. 30, but further comprising various configurations for generating a stability portion 1108 of the incision. FIG. 31A is directed to a stability portion 1108 comprising a protrusion 1110 that may be configured to be constrained to be outside of the correction portion of the incision relative to the axis of motion 12 (as may be defined by the boundary 1150 and / or the incision 47). Alternatively, FIG. 31B is directed to a configuration for the protrusion 1110 that may be configured to be located nominally opposite the hinge 1020, since the hinge 1020 itself essentially provides an amount of stability against displacement of the flap 40. The inherent stability may be a function of the size and / or length of the hinge 1020. Alternatively, FIG. 31C is directed to a configuration for the stability portion 1108 that may be configured to comprise multiple protrusions 1110.

[0164] 32A and 32B are directed to example embodiments in which the contact element 804 further comprises various configurations for generating one or more stability portions 1108 of the incision. As shown in FIG. 32A, the contact element 804 may be considered a "correction portion" as described elsewhere herein and may be bounded by a boundary 818, and may be configured to provide a correction portion 819 to the incision via at least a portion of the contact surface 806 that is inside the visual aperture 1150. The contact element 804 may further be configured to comprise a stability portion 1108 or multiple stability portions 1108 that are outside the visual aperture 1150. The stability portion 1108 may further be configured to generate nominally complementary features, such as a protrusion 1110 by deforming (or equivalently, "shaping") the tissue with a recess 1181, and / or a depression 1112 by shaping the tissue using a protrusion 1182, respectively. The recesses 1181 may be configured to have a width 1186 and a depth 1185, as shown in FIG. 32B. Similarly, the protrusions 1182 may be configured to have a width 1186 and a height 1185. The recesses 1181 and protrusions 1182 may be configured to utilize a width between 50 μm and 1,500 μm, a height between 50 μm and 700 μm, and a depth between 50 μm and 700 μm. The recesses 1181 and protrusions 1182 may further be configured to utilize a width between 200 μm and 600 μm, a height between 100 μm and 300 μm, and a depth between 100 μm and 300 μm.

[0165] 32B shows a cross-sectional view of the embodiment of FIG. 32A in which the surface 806 can be seen to be hemispherical, as the present disclosure may be deployed to generate, for example, corneal strips, which may be used to correct simple myopia. The stability portion (or equivalently, "stability region") 1108 can be seen to comprise an area about the optically clear aperture 1150 and beyond about the edge of the contact element 804 bounded by the housing 8042. It should be understood that various combinations of such recesses 1181 and protrusions 1182 may be combined to form more complex stability portions 1108.

[0166] 33 is directed to an embodiment comprising both a correction portion 1108 and a stability portion 819, and further comprising sides of those shown in FIGS. 10A-10F and 26-30 configured to generate an incision that may comprise complementary features protrusions 1110 and indentations 1112 as shown in FIGS. 24A-26. The contact plate 804 may comprise indentations 1181 (or equivalently, as used herein, “channels”) that may be fabricated to contact the tissue surface and reshape the tissue surface from its free-standing state, affecting at least a portion of the underlying volume of tissue 1111 (nominally within and around the area enclosed by the dashed lines, as shown), generating protrusions 1110 and complementary indentations 1112, respectively, on different sides of the incision, such as the flap and foundation, in the case of an exemplary corneal incision. More broadly, the incision made through at least a portion of the underlying tissue volume 1111 along the incision profile may create a first incision surface proximal to the tissue surface and a second incision surface distal to the tissue surface. The incision profile may be planar when the tissue is shaped with the contact elements, such as when the elongated electrode is advanced and / or retracted along a nominally linear path, as described elsewhere herein. The subsequent resulting free-standing (or "relaxed") tissue shape may be considered the inverse of the shape imparted to the tissue during incision. Shaping the tissue into a configuration that is more concave than that of its normally relaxed state during incision, such as a nominally planar incision, may result in a tissue shape that is less concave (or equivalently, more convex) when the tissue later returns to the relaxed tissue shape. Shaping tissue into a configuration that is more convex than its normally relaxed state during dissection, such as a nominally planar dissection, can result in a less convex (or equivalently, more concave) tissue shape when the tissue later returns to the relaxed tissue shape. The resulting shape can be imparted to the tissue differently than in its (their) relaxed state, particularly during dissection, when the contact elements are engaged and shape the tissue surface and / or a volume of tissue below the tissue surface.The tissue contacting element 804 may sufficiently shape the tissue to allow it to form one or more complementary features along the incision profile as the tissue relaxes to its modified freestanding configuration upon removal of and / or pressure thereon. The optically clear opening 1150 may be defined as the area between the dashed lines 1150 shown in this cross-sectional view, and the resulting incision may have both the correction portion 819 and the stability portion 1108. In some embodiments, the optically clear opening 1150 comprises an optical zone of refractive correction, the outer boundary of which corresponds to the perimeter of the incised corneal strip. The stability portion may be defined as the area outside the correction portion, which may also be outside the optically clear opening. The tissue 2 may be drawn into the channel 1212 of the suction element 810 by suction to affix and / or stabilize the tissue 2. The channel 1212 is outside the incision boundary 1114 (not shown for clarity, but may be considered as the area defined by the intersection of the electrode 702 and the tissue 2) and therefore may not contribute to creating the stable portion 1108 of the incision.

[0167] FIG. 34 is directed to an embodiment similar to that of FIG. 33, with a contact plate 804 modified to include protrusions 1182 that can be fabricated to contact and reshape the tissue surface and affect at least a portion of the underlying volume of the tissue 1111, creating depressions 1112 and complementary protrusions 1110, in the case of an exemplary corneal incision, on different sides of the incision, such as the flap and base, respectively.

[0168] FIG. 35 is directed to an embodiment similar to that of FIG. 33. As described herein above, tissue 2 may be drawn into channel 1210 by suction provided by suction element 810 to generate complementary features 1110 and 1112 in stability region 1108. Channel 1212 may be outside incision boundary 1114 (not shown for clarity, but may be considered to be outside the region defined by the intersection of electrode 702 and tissue 2, and disposed between channels 1210 and 1212 in this exemplary embodiment). Tissue 2 drawn into channel 1210 may be disposed within the cutting region, shown in this exemplary embodiment as being "above" electrode 702 to form protrusions 1110 and recesses 1112, while tissue 2 drawn into channel 1212 is disposed "below" the electrode and outside the cutting region, and thereby may not be incised. The optical clear aperture 1150 (as described with respect to Figures 26 and 30-33) can be considered to be approximately the width of the contact plate 804 in this exemplary embodiment.

[0169] 36 is directed to an embodiment similar to that of FIGS. 11A and 11B, with the addition of an optical clear aperture 1150, which may divide element 8061 into two regions: Region 1, element 8061-1, which is within (or "inside") the optical aperture and intended to provide a refractive surface and generate a corneal leaflet, and Region 2, element 8061-2, which is without (or "outside") the optical clear aperture. Element 8061-2 may be configured to provide complementary features to produce a stabilizing portion 819 of the incision.

[0170] Because a typical cornea may be on average 500 μm thick and may require at least 250 μm of corneal stroma to remain to prevent typical IOP from causing instability or overbulging ("eklasisa"), creating a protrusion in / on the corneal foundation may be preferable to creating a protrusion in / on the flap. Alternatively, it may be preferable to configure the system to create a depression in / on the corneal foundation resulting in a stromal thickness of ≧250 μm.

[0171] Creating a stabilizing portion of the incision that is located opposite the hinge portion may provide more stability than one more closely adjacent to the hinge portion.

[0172] The shapes of the complementary features shown herein are primarily rectangular in depth cross-section, although other shapes are considered within the scope of the present disclosure. As non-limiting examples, the depth cross-sectional shapes of the complementary features may be selected from the group consisting of protrusions, recesses, indentations, rectangles, rounded rectangles, circles, ellipses, quadrilaterals, rhombus, parallelograms, trapezoids, trapezoids, closed curves, and combinations thereof.

[0173] Any dissection instrument, such as a conventional microkeratome (or a device of equivalent functionality), may also be used to create an incision with a stabilizing portion. For example, a conventional microkeratome may be modified to create a corneal flap further comprising a stabilizing portion by providing at least one of channels 1210 and / or 1212 in the suction element of the device and / or at least one of recesses 1181 and protrusions 1182 in the applanation plate of the device to be impacted by the cutting element of the dissection device to create complementary features of the incision.

[0174] 24A-26 and 33-36, the system can be configured to dissect tissue in a number of ways. In some embodiments, a processor is configured to perform one or more steps of the method. In some embodiments, a processor, such as a controller, is configured to advance and retract the electrode in response to processor controlled movements. In some embodiments, the tissue contacting element is configured to shape the tissue with suction elements 810 and channels 1210, and the tissue is dissected as the electrode is advanced and retracted. In some embodiments, the tissue surface comprises a first surface profile corresponding to a first tissue ablation profile while the electrode is advanced and a second surface profile while the electrode is retracted, defining a volume of ablated tissue corresponding to the difference between the first and second surface profiles, as described herein. In some embodiments, the volume of ablated tissue corresponds to a correction portion 819 within a stability portion 1108 of the profile of the incision 45, as described herein.

[0175] In some embodiments, the tissue contacting element comprises an adjustable contact element configured to shape the tissue to a first surface profile to incise the tissue along the first tissue incision profile and to a second surface profile to incise the tissue along the second incision profile. In some embodiments, the adjustable contact element comprises element 8061 as described herein. In some embodiments, element 8061 comprises a first element 8061-1 for defining the first and second surface profiles of the compensation portion 819, for example, as the electrode is advanced and retracted, and a second element 8061-2 that remains substantially fixed while the electrode is advanced and retracted and defines, together with the incision 45, a complementary feature of the stability portion 1108.

[0176] This tissue shaping with the contact elements allows any suitable shape, e.g., a three-dimensional shape, to be formed with a generally linear dissection profile when the tissue is dissected with the electrodes. In some embodiments, the dissection profile 45 constitutes a two-dimensional linear dissection profile when the tissue is engaged with the contact elements, and the one or more complementary features constitute a three-dimensional complementary surface profile, e.g., protrusions 1110 and complementary depressions 1112, when the tissue relaxes into a free-standing configuration.

[0177] Combinations of the above configurations are also considered within the scope of the present disclosure.

[0178] As used herein, the terms "flexion," "deformation," "vibration," "extension," and "bending" may be used interchangeably.

[0179] As used herein in reference to tissue interactions, the terms "disrupt," "degrade," and "ablate" may be used synonymously.

[0180] The symbol "~" is used herein as equivalent to "about." For example, a statement such as "~100 ms" is equivalent to a statement such as "about 100 ms" and "~100 ms" is equivalent to a statement such as "~100 ms." t =~5mm s -1 " etc. are written as "v t is about 5 mm s -1 This is comparable to the description "is."

[0181] symbol [ka] is used herein to indicate that the value that follows is a diameter. For example, [ka] is comparable to the statement "diameter of 10 μm." [ka] etc. is comparable to a statement of "diameter of approximately 12 μm."

[0182] The symbol "∝" is used herein to indicate proportionality. For example, "∝r -2 " etc. are written as "r -2 This is comparable to the statement "proportional to."

[0183] Dot notation is used herein to represent compound units for clarity and brevity. For example, the notation k = ~40 N m -1 is equivalent to saying "k=~40N / meter".

[0184] As used herein, "mN" refers to "millinewtons," which is 10 -3 It's Newton.

[0185] As described herein, the computing devices and systems described and / or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions such as those contained within the modules described herein. In their most basic configurations, these computing devices may each include at least one memory device and at least one physical processor.

[0186] The term "memory" or "memory device" as used herein generally refers to any type or form of volatile or non-volatile storage device or medium capable of storing data and / or computer-readable instructions. In one embodiment, a memory device may store, load, and / or maintain one or more of the modules described herein. Examples of memory devices include, but are not limited to, random access memory (RAM), read-only memory (ROM), flash memory, hard disk drive (HDD), solid-state drive (SSD), optical disk drive, cache, any variation or combination of one or more of the same, or any other suitable storage memory.

[0187] Additionally, the term "processor" or "physical processor" as used herein generally refers to any type or form of hardware-implemented processing unit capable of interpreting and / or executing computer-readable instructions. In one embodiment, the physical processor may access and / or modify one or more modules stored in the memory device described above. Examples of physical processors include, but are not limited to, a microprocessor, a microcontroller, a central processing unit (CPU), a field programmable gate array (FPGA) implementing a soft-core processor, an application specific integrated circuit (ASIC), a portion of one or more of the same, a variation or combination of one or more of the same, or any other suitable physical processor. The processor may comprise a distributed processor system, e.g., a parallel processor invocation, or a remote processor such as a server, and combinations thereof.

[0188] Although illustrated as separate elements, the method steps described and / or illustrated herein may represent parts of a single application. Additionally, in some embodiments, one or more of these steps may represent or correspond to one or more software applications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks, such as method steps.

[0189] In addition, one or more of the devices described herein may transform data, physical devices, and / or representations of physical devices from one form to another. Additionally or alternatively, one or more of the modules listed herein may transform a processor, volatile memory, non-volatile memory, and / or any other portion of a physical computing device from one form of computing device to another form of computing device by executing on the computing device, storing data on the computing device, and / or otherwise interacting with the computing device.

[0190] The term "computer-readable medium" as used herein generally refers to any form of device, carrier, or medium capable of storing or carrying computer-readable instructions. Examples of computer-readable media include, but are not limited to, transmission-type media such as carrier waves, and non-transitory type media such as magnetic storage media (e.g., hard disk drives, tape drives, and floppy disks), optical storage media (e.g., compact discs (CDs), digital video discs (DVDs), and BLU-RAY discs), electronic storage media (e.g., solid-state drives and flash media), and other distributed systems.

[0191] Those skilled in the art will recognize that any process or method disclosed herein can be modified in many ways. The process parameters and sequence of steps described and / or illustrated herein are given as examples only and can be varied as desired. For example, although the steps illustrated and / or described herein are shown or discussed in a particular order, these steps do not necessarily have to be performed in the order shown or discussed.

[0192] The various exemplary methods described and / or illustrated herein may also omit one or more of the steps described or illustrated herein, or may comprise additional steps in addition to those disclosed. Furthermore, the steps of any method as disclosed herein can be combined with any one or more steps of any other method as disclosed herein.

[0193] A processor as described herein may be configured to perform one or more steps of any of the methods disclosed herein. Alternatively, or in combination, a processor may be configured to combine one or more steps of one or more methods as disclosed herein.

[0194] Unless otherwise stated, as used in the specification and claims, the terms "connected to" and "coupled to" (and their derivatives) are intended to be interpreted as allowing for both direct and indirect (i.e., via other elements or components) connections.

[0195] Unless otherwise noted, the terms "operatively connected to" and "operatively coupled to" (and derivatives thereof) as used in this specification and claims are intended to be interpreted as allowing for both direct and indirect (i.e., via other elements or components) connections to perform functions.

[0196] Additionally, the terms "a" and "an," as used in the specification and claims, are intended to mean "at least one of." Finally, for ease of use, the terms "including" and "having" (and their derivatives) as used in the specification and claims are intended to be synonymous with and have the same meaning as the word "comprising."

[0197] A processor as disclosed herein may be configured with instructions to perform any one or more steps of any method as disclosed herein.

[0198] It should be understood that the terms "first," "second," "third," etc. may be used herein to describe various layers, elements, components, regions, or sections without referring to any particular order or sequence of events. These terms are merely used to distinguish one layer, element, component, region, or section from another layer, element, component, region, or section. A first layer, element, component, region, or section as described herein could be referred to as a second layer, element, component, region, or section without departing from the teachings of the present disclosure.

[0199] As used herein, the term "or" is used inclusively to refer to items both as alternatives and in combination.

[0200] As used herein, letters such as numbers refer to similar elements.

[0201] The drawings are not necessarily drawn to scale and some dimensions may be disproportionate for illustrative purposes.

[0202] This disclosure includes the following numbered appendices:

[0203] Addendum 1. A method of incising tissue, comprising: shaping a tissue surface with a tissue contacting element comprising one or more channels or protrusions to form one or more corresponding protrusions or depressions in the tissue surface; incising the tissue along the tissue incision profile; and removing the contacting element and allowing the tissue to relax into a free-standing configuration and form one or more complementary features along the tissue incision profile.

[0204] Addendum 2. The method of Addendum 1, wherein the one or more complementary features comprise a protrusion on a first side of the tissue incision profile and a recess on a second side of the incision profile, stabilizing the tissue in a free-standing configuration at an interface between the first and second sides of the tissue incision profile.

[0205] Appendix 3. The method of Appendix 2, wherein the tissue incision profile defines a first portion of tissue on a first side of the incision profile and a second portion on a second side of the incision profile, the first portion comprising one or more protrusions and the second portion comprising one or more corresponding recesses sized and shaped to receive the one or more protrusions in the relaxed configuration.

[0206] Clause 4. The method of clause 3, wherein the one or more protrusions comprise a plurality of protrusions on a first side of the incision profile and the one or more corresponding depressions comprise a plurality of corresponding depressions on a second side of the incision profile in the relaxed configuration.

[0207] Clause 5. The method of clause 4, wherein the plurality of protrusions and the plurality of recesses constitute a plurality of interlocking features.

[0208] Clause 6. The method of clause 3, wherein the first portion comprises a tissue surface and the second portion comprises a layer of tissue.

[0209] Clause 7. The method of clause 3, wherein the second portion comprises a tissue surface and the first portion comprises a layer of tissue.

[0210] Appendix 8. The method of Appendix 1, wherein one or more of the channels or protrusions of the contact element comprise channels, the channels being sized to receive the tissue surface and form corresponding protrusions along the tissue incision profile in a freestanding configuration.

[0211] Clause 9. The method of clause 8, wherein the tissue incision profile defines a first portion of tissue on a first side of the incision profile and a second portion on a second side of the incision profile, the first portion comprising a protrusion and the second portion comprising a corresponding recess sized and shaped to receive the protrusion.

[0212] Clause 10. The method of clause 9, wherein the protrusion on the first portion and the recess on the second portion form an interlocking configuration.

[0213] Appendix 11. The method of appendix 1, wherein one or more of the channels or protrusions of the contact element comprise protrusions that, in a free-standing configuration, are sized to indent the tissue surface along the tissue incision profile and form a corresponding depression.

[0214] Clause 12. The method of clause 11, wherein the tissue incision profile defines a first portion of tissue on a first side of the incision profile and a second portion on a second side of the incision profile, the first portion comprising a recess and the second portion comprising a corresponding protrusion sized and shaped to fit within the recess.

[0215] Clause 13. The method of clause 12, wherein the recess on the first portion and the protrusion on the second portion form an interlocking configuration.

[0216] Clause 14. The method of clause 1, wherein the incision profile constitutes a linear incision profile when the tissue is incised with the electrode.

[0217] Addendum 15. The method of Addendum 14, wherein the incision profile constitutes a two-dimensional linear incision profile when the tissue is engaged with the contact element, and the one or more complementary features constitute a three-dimensional complementary surface profile when the tissue relaxes into a free-standing configuration.

[0218] Clause 16. The method of clause 1, wherein the one or more complementary features constitute one or more of an interlocking feature or an interlocking feature.

[0219] Clause 17. The method of clause 1, wherein the one or more complementary features extend along an outer region of the tissue incision profile, at least partially around an inner region of the tissue incision profile.

[0220] Clause 18. The method of clause 17, wherein the one or more complementary features extend semi-circumferentially around the inner region of the incision profile.

[0221] Clause 19. The method of clause 1, wherein the one or more complementary features extend along an outer region of the tissue incision profile and define a central optical zone of the cornea of ​​the eye.

[0222] Appendix 20. The method of Appendix 1, wherein the tissue is incised with advancing and retracting the electrode, the tissue surface comprising a first surface profile corresponding to a first tissue ablation profile while the electrode is advanced and a second surface profile while the electrode is retracted, defining a volume of ablated tissue corresponding to the difference between the first surface profile and the second surface profile.

[0223] Clause 21. The method of clause 20, wherein the tissue contact element comprises an adjustable contact element, and the tissue surface is shaped into the first surface profile and the second surface profile using the adjustable contact element.

[0224] Clause 22. The method of clause 21, wherein the adjustable contact element comprises an inner element for defining the first surface profile and the second surface profile, and an outer element for defining one or more complementary features.

[0225] Clause 23. The method of clause 20, wherein a first portion of the tissue surface corresponding to the one or more complementary features remains substantially fixed while the tissue is incised with electrode advancement and electrode retraction, and a second portion of the tissue surface constitutes a first surface profile while the electrode is advanced and a second surface profile while the electrode is retracted.

[0226] Addendum 24. The method of Addendum 23, wherein the second portion of the tissue surface corresponds to an optical zone and corrects refractive error of the eye.

[0227] Clause 25. The method of clause 24, wherein a difference between the first surface profile and the second surface profile corresponds to a change in optical power of the optical zone.

[0228] Clause 26. The method of clause 23, wherein the excised tissue is removed from the excised tissue volume.

[0229] 27. The method of claim 26, wherein the ablated tissue comprises corneal tissue and the tissue removed from the volume comprises a corneal graft.

[0230] Addendum 28. The method of Addendum 26, wherein the volume corresponds to a volume of an implant to be placed in the tissue.

[0231] Clause 29. The method of clause 1, wherein the one or more complementary features have a width in the range of about 30 μm to about 500 μm and a depth in the range of about 30 μm to about 450 μm.

[0232] Clause 30. The method of clause 29, wherein the one or more complementary features have a length in the range of about 50 μm to about 3,000 μm.

[0233] Clause 31. The method of clause 29, wherein the one or more complementary features comprise a plurality of complementary features separated by a distance in the range of about 200 μm to about 1,000 μm.

[0234] Clause 32. The method of clause 1, wherein the one or more complementary features comprise a protrusion on a first side of the incision profile and a recess on a second side of the incision profile that is shaped to receive the protrusion.

[0235] Addendum 33. The method of Addendum 32, wherein one or more of the channels or protrusions of the contact element have a width in the range of about 50 μm to about 500 μm, and the protrusions on the first side of the incision profile and the depressions on the second side of the incision profile each have a width in the range of about 30 μm to about 500 μm.

[0236] Addendum 34. The method of Addendum 32, wherein one or more of the channels or protrusions of the contact element have a depth in the range of about 50 μm to about 500 μm, and the protrusions on the first side of the incision profile and the recesses on the second side of the incision profile each have a depth in the range of about 30 μm to about 450 μm.

[0237] Clause 35. The method of clause 32, wherein one or more of the protrusions or channels of the contact element comprise a plurality of channels or protrusions separated by a distance in the range of about 200 μm to about 1,000 μm, the protrusions on the first side of the incision comprise a plurality of protrusions separated by a distance in the range of about 200 μm to about 500 μm, and the depressions on the second side of the incision comprise a plurality of depressions separated by corresponding distances in the range of about 200 μm to about 1,000 μm.

[0238] Addendum 36. The method of Addendum 1, wherein one or more of the protrusions or channels are shaped to engage tissue, the plurality of channels each having a width in the range of about 50 μm to about 500 μm and a length in the range of about 50 μm to about 3,000 μm, and the plurality of channels are separated by a distance in the range of about 200 μm to about 1,000 μm.

[0239] Addendum 37. The method of Addendum 1, wherein one or more of the protrusions or channels comprise a plurality of protrusions shaped to engage tissue, each of the plurality of protrusions having a width in the range of about 50 μm to about 500 μm and a length in the range of about 50 μm to about 3,000 μm, and the plurality of protrusions are separated by a distance in the range of about 200 μm to about 1,000 μm.

[0240] Addendum 38. The method of Addendum 1, wherein the contact element is coupled to a vacuum source to engage the contact element with tissue.

[0241] Addendum 39. The method of Addendum 38, comprising a channel, one or more of the channels or protrusions being coupled to a vacuum source, to draw tissue into the channel and shape the tissue surface with a corresponding protrusion on the tissue surface.

[0242] Addendum 40. The method of Addendum 38, wherein one or more of the channels or protrusions comprise a protrusion that is coupled to a vacuum source proximate the protrusion, the protrusion being coupled to the channel and forming a corresponding depression in the tissue surface.

[0243] Clause 41. The method of clause 38, wherein the vacuum source provides a vacuum pressure in the range of about 100 mmHg to about 600 mmHg.

[0244] Addendum 42. The method of Addendum 1, wherein the electrode comprises an elongated electrode configured to flex, generate plasma, and incise tissue; an electrical energy source operatively coupled to the elongated electrode and providing electrical energy to the electrode to generate plasma; and a tensioning element operatively coupled to the elongated electrode and providing tension to the elongated electrode, enabling the elongated electrode to flex in response to engaging the tissue and generating plasma.

[0245] Clause 43. The method of clause 42, wherein the plurality of arms are operably coupled to the electrode and the tension element.

[0246] Clause 44. The method of clause 43, wherein the electrode is not supported between the two arms.

[0247] Addendum 45. A system for incising tissue with plasma, comprising: an elongated electrode configured to incise tissue along a tissue incision profile; and a tissue contacting element configured to shape the tissue, the tissue contacting element comprising one or more channels or protrusions to form one or more corresponding protrusions or depressions in the tissue surface while the tissue is incised with the electrode along the incision profile, the tissue contacting element shaping the tissue sufficiently to allow the tissue to form one or more complementary features along the incision profile when the tissue relaxes into a freestanding configuration upon removal of the tissue contacting element.

[0248] Clause 46. The system of clause 45, wherein the one or more complementary features comprise a protrusion on a first side of the tissue-cutting profile and a recess on a second side of the cutting profile to stabilize the tissue in a free-standing configuration at an interface between the first and second sides of the tissue-cutting profile.

[0249] Addendum 47. The system of Addendum 46, wherein the tissue incision profile defines a first portion of tissue on a first side of the incision profile and a second portion on a second side of the tissue incision profile, the first portion comprising a protrusion and the second portion comprising a corresponding recess sized and shaped to receive the protrusion.

[0250] Clause 48. The system of clause 47, wherein the first portion comprises a tissue surface and the second portion comprises a layer of tissue.

[0251] Clause 49. The system of clause 47, wherein the second portion comprises a tissue surface and the first portion comprises a layer of tissue.

[0252] Addendum 50. The system of Addendum 45, wherein one or more of the channels or protrusions of the contact element comprise channels, the channels being sized in a freestanding configuration to receive a tissue surface and form corresponding protrusions and recesses along the tissue incision profile.

[0253] Addendum 51. The system of Addendum 45, wherein one or more of the channels or protrusions of the contact element comprise protrusions that, in a free-standing configuration, are sized to indent the tissue surface along the tissue incision profile and form corresponding protrusions and depressions.

[0254] Clause 52. The system of clause 45, further comprising an actuator for translating the electrode.

[0255] Addendum 53. The system of Addendum 52, wherein the tissue cutting profile constitutes a linear cutting profile when the tissue is cut with translation of the electrode.

[0256] Addendum 54. The system of Addendum 53, wherein the tissue incision profile constitutes a two-dimensional linear incision profile when the tissue is engaged with the contact element, and the one or more complementary features constitute a three-dimensional complementary surface profile when the tissue relaxes into a free-standing configuration.

[0257] Addendum 55. The system of Addendum 45, wherein the tissue contact element comprises an adjustable contact element configured to shape tissue to a first surface profile to resect tissue along a first tissue resection profile and to a second surface profile to resect tissue along a second incision profile.

[0258] Clause 56. The system of clause 55, wherein a difference between the first tissue ablation profile and the second tissue ablation profile defines a volume of ablated tissue.

[0259] Addendum 57. The system of Addendum 55, wherein the adjustable contact element comprises a first surface profile configuration for shaping tissue to a first surface profile and a second surface profile configuration for shaping tissue to a second surface profile configuration.

[0260] Addendum 58. The system of Addendum 55, wherein the adjustable contact element comprises an inner element for defining the first surface profile and the second surface profile, and an outer element for defining one or more complementary features.

[0261] Addendum 59. The system of Addendum 58, wherein the outer element is configured to remain substantially fixed while the tissue is incised with advancement of the electrode and retraction of the electrode, and the inner element is configured to shape the tissue to a first surface profile with a first configuration while the electrode is advanced and to a second surface profile with a second configuration while the electrode is retracted.

[0262] Addendum 60. The system of Addendum 45, wherein one or more of the channels or protrusions comprise a plurality of channels forming a plurality of protrusions and a plurality of corresponding complementary features in the tissue surface.

[0263] Addendum 61. The system of Addendum 60, wherein the multiple channels of the contact element are separated from one another by a distance in the range of about 200 μm to about 1,000 μm.

[0264] Addendum 62. The system of Addendum 45, wherein one or more of the channels or protrusions comprise a plurality of protrusions forming a plurality of depressions and a plurality of corresponding complementary features in the tissue surface.

[0265] Addendum 63. The system of Addendum 62, wherein the multiple protrusions of the contact element are separated from one another by a distance in the range of about 200 μm to about 1,000 μm.

[0266] Addendum 64. The system of Addendum 45, wherein one or more of the channels or protrusions of the contact element have a width in the range of about 50 μm to about 500 μm.

[0267] Addendum 65. The system of Addendum 45, wherein one or more of the channels or protrusions of the contact element have a depth within the range of about 50 μm to about 500 μm.

[0268] Addendum 66. The system of Addendum 45, further comprising a vacuum source coupled to the contact element for shaping tissue with the contact element.

[0269] Addendum 67. The system of Addendum 66, comprising a channel, one or more of the channels or protrusions coupled to a vacuum source, for drawing tissue into the channel and shaping the tissue surface with a corresponding protrusion on the tissue surface.

[0270] Addendum 68. The system of Addendum 66, wherein one or more of the channels or protrusions include a protrusion that is coupled to a vacuum source proximate the protrusion, the protrusion being coupled to the channel and forming a corresponding depression in the tissue surface.

[0271] Addendum 69. The system of Addendum 66, wherein the vacuum source provides a vacuum pressure in the range of about 100 mmHg to about 600 mmHg.

[0272] Clause 70. The system of clause 45, further comprising: an electrical energy source operably coupled to the elongated electrode and configured to provide electrical energy to the electrode and generate plasma; and a tensioning element operably coupled to the elongated electrode, configured to provide tension to the elongated electrode and enable the elongated electrode to flex in response to the elongated electrode engaging tissue and generating plasma.

[0273] Clause 71. The system of clause 70, further comprising a plurality of arms operably coupled to the electrodes and the tensioning element.

[0274] Item 72. The system of item 71, wherein the electrode is not supported between the two arms.

[0275] Clause 73. The system of clause 45, further comprising a processor configured to perform the method of any one of the preceding method clauses.

[0276] The embodiments of the present disclosure are shown and described herein and are provided by way of example only. Those skilled in the art will recognize numerous adaptations, modifications, variations, and substitutions without departing from the scope of the present disclosure. Several substitutions and combinations of the embodiments disclosed herein may be utilized without departing from the scope of the present disclosure and the inventions disclosed herein.

Claims

1. 1. A system for cutting tissue with plasma, comprising: an elongate electrode configured to incise the tissue along a tissue incision profile; a tissue contacting element configured to shape the tissue, the tissue contacting element comprising one or more channels or protrusions to form one or more corresponding protrusions or depressions in a tissue surface while the tissue is incised with the electrode along the incision profile, the tissue contacting element sufficiently shaping the tissue to allow the tissue to form one or more complementary features along the incision profile when the tissue relaxes into a freestanding configuration upon removal of the tissue contacting element; A system comprising:

2. 2. The system of claim 1, wherein the one or more complementary features comprise a protrusion on a first side of the tissue dissecting profile and a recess on a second side of the dissecting profile to stabilize the tissue in the free-standing configuration at an interface between the first and second sides of the tissue dissecting profile.

3. 3. The system of claim 2, wherein the tissue dissecting profile defines a first portion of tissue on a first side of the dissecting profile and a second portion on a second side of the tissue dissecting profile, the first portion comprising the protrusion and the second portion comprising a corresponding recess sized and shaped to receive the protrusion.

4. The system of claim 3 , wherein the first portion comprises the tissue surface and the second portion comprises a layer of tissue.

5. The system of claim 3 , wherein the second portion comprises the tissue surface and the first portion comprises a layer of tissue.

6. 2. The system of claim 1, wherein one or more of the channels or protrusions of the contact element comprise channels that, in the freestanding configuration, are sized to receive the tissue surface and form corresponding protrusions and recesses along the tissue incision profile.

7. 2. The system of claim 1, wherein one or more of the channels or protrusions of the contact element comprise protrusions that, in the freestanding configuration, are sized to indent the tissue surface along the tissue incision profile and form corresponding protrusions and depressions.

8. The system of claim 1 , further comprising an actuator for translating the electrode.

9. The system of claim 8 , wherein the tissue dissection profile constitutes a linear dissection profile as the tissue is dissected with translation of the electrode.

10. 10. The system of claim 9, wherein the tissue incision profile comprises a two-dimensional linear incision profile when the tissue is engaged with the contact element, and the one or more complementary features comprise a three-dimensional complementary surface profile when the tissue relaxes into the freestanding configuration.

11. 2. The system of claim 1, wherein the tissue contacting element comprises an adjustable contact element configured to shape the tissue to a first surface profile to resect the tissue along a first tissue resection profile and to a second surface profile to resect the tissue along a second incision profile.

12. The system of claim 11 , wherein a difference between the first tissue ablation profile and the second tissue ablation profile defines a volume of ablated tissue.

13. 12. The system of claim 11, wherein the adjustable contact element comprises a first surface profile configuration for shaping the tissue to the first surface profile and a second surface profile configuration for shaping the tissue to the second surface profile configuration.

14. 12. The system of claim 11, wherein the adjustable contact element comprises an inner element for defining the first surface profile and the second surface profile and an outer element for defining the one or more complementary features.

15. 15. The system of claim 14, wherein the outer element is configured to remain substantially fixed while the tissue is incised with advancement of the electrode and retraction of the electrode, and the inner element is configured to mold the tissue to the first surface profile with a first configuration while the electrode is advanced and to the second surface profile with a second configuration while the electrode is retracted.

16. The system of claim 1 , wherein one or more of the channels or protrusions comprises a plurality of channels forming a plurality of protrusions and a plurality of corresponding complementary features in the tissue surface.

17. 17. The system of claim 16, wherein the channels of the contact element are separated from one another by a distance in a range of about 200 μm to about 1,000 μm.

18. The system of claim 1 , wherein one or more of the channel or protrusions comprises a plurality of protrusions forming a plurality of depressions and a plurality of corresponding complementary features in the tissue surface.

19. 20. The system of claim 18, wherein the protrusions of the contact element are separated from one another by a distance in a range of about 200 μm to about 1,000 μm.

20. The system of claim 1 , wherein one or more of the channels or protrusions of the contact element comprise a width in a range of about 50 μm to about 500 μm.

21. The system of claim 1 , wherein one or more of the channels or protrusions of the contact element comprise a depth within a range of about 50 μm to about 500 μm.

22. The system of claim 1 , further comprising a vacuum source coupled to the contact element for shaping the tissue with the contact element.

23. 23. The system of claim 22, wherein one or more of the channels or protrusions comprises a channel coupled to the vacuum source to draw tissue into the channel and shape the tissue surface with a corresponding protrusion of the tissue surface.

24. 23. The system of claim 22, wherein one or more of the channel or protrusion comprises a protrusion that is coupled to a channel that is coupled to the vacuum source proximate to the protrusion and forms a corresponding depression in the tissue surface.

25. The system of claim 22, wherein the vacuum source provides a vacuum pressure in the range of about 100 mmHg to about 600 mmHg.

26. an electrical energy source operably coupled to the elongated electrode and configured to provide electrical energy to the electrode to generate the plasma; and a tensioning element operably coupled to the elongated electrode, the tensioning element configured to provide tension to the elongated electrode and to enable the elongated electrode to flex in response to the elongated electrode engaging the tissue and generating the plasma; The system of claim 1 further comprising:

27. 27. The system of claim 26, further comprising a plurality of arms operably coupled to the electrodes and the tensioning element.

28. 28. The system of claim 27, wherein the electrode is not supported between the two arms.

29. The system further comprising a processor, the processor comprising: shaping the tissue surface with the tissue contacting element comprising the one or more of the channels or protrusions to form the one or more of the corresponding protrusions or depressions in the tissue surface; incising the tissue along the tissue incision profile; removing the contact element and allowing the tissue to relax into the freestanding configuration and form the one or more complementary features along the tissue incision profile; The system of claim 1 configured to:

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