Patent Application
20210401624
The present disclosure relates generally to laser surgical systems, and more particularly to laser surgical systems that can create incisions in an eye.
Ophthalmic laser surgical systems generate a pulsed femtosecond laser beam and direct the laser pulses to focus spots of an ophthalmic tissue. When the beam intensity or energy density exceeds a plasma or photodisruption threshold at a focus spot, a plasma or cavitation bubble is created in the tissue. During surgery, the laser beam can be scanned along a three-dimensional scan pattern to create a layer of bubbles that form an incision.
In laser-assisted cataract surgery (LACS), a laser may be used to form particular types of incisions. For example, the laser may be used to make an incision in the cornea into which a surgical instrument may be placed to access the interior of the eye. The incision should be designed to avoid excess leakage from the incision.
In certain embodiments, a laser surgical system comprises a laser source, scanners, delivery optics, and a computer. The laser source generates a beam of femtosecond laser pulses. The scanners direct focus spots of the beam towards points of the cornea of an eye, where the cornea has a posterior corneal surface and an anterior corneal surface. The delivery optics focuses the focus spots at the points of the cornea. The computer creates a three-dimensional incision in the cornea by instructing the optics and the scanners to: direct and focus the focus spots from the posterior corneal surface, through a convex curve and a concave curve, to the anterior corneal surface to form an S-curve incision with a posterior end and an anterior end. The S-curve incision has a substantially non-planar rectangular shape with a longer side and a shorter side. The longer side extends from the posterior end to the anterior end and defines a longer direction. A shorter direction is substantially perpendicular to the longer direction. A cross-section of the incision in the longer direction exhibits the convex curve and the concave curve. The convex curve is convex relative to the anterior corneal surface, and the concave curve is concave relative to the anterior corneal surface.
Embodiments may include none, one, some, or all of the following features:
In certain embodiments, a method of creating an incision in an eye includes generating, by a laser source, a beam of femtosecond laser pulses. Focus spots of the beam are directed, by scanners, towards points of the cornea of an eye, where the cornea has a posterior corneal surface and an anterior corneal surface. The focus spots are focused, by delivery optics, at the points of the cornea. A three-dimensional S-curve incision in the cornea is created by a computer. The S-curve incision has a substantially non-planar rectangular shape with a longer side and a shorter side. The longer side extends from an anterior end to a posterior end and defines a longer direction. A shorter direction is substantially perpendicular to the longer direction. The computer creates the S-curve incision by controlling the optics and the scanners to direct and focus the focus spots to: create the posterior end of the S-curve incision; create a portion of the S-curve incision with a convex curve and a concave curve; and create the anterior end of the S-curve incision. The convex curve is convex relative to the anterior corneal surface, and the concave curve is concave relative to the anterior corneal surface.
Embodiments may include none, one, some, or all of the following features:
Referring now to the description and drawings, example embodiments of the disclosed apparatuses, systems, and methods are shown in detail. The description and drawings are not intended to be exhaustive or otherwise limit the claims to the specific embodiments shown in the drawings and disclosed in the description. Although the drawings represent possible embodiments, the drawings are not necessarily to scale and certain features may be simplified, exaggerated, removed, or partially sectioned to better illustrate the embodiments.
In general, the present disclosure relates to an ophthalmic laser surgical system that creates an S-curve incision in the cornea of an eye, which may be used as, e.g., a primary incision for cataract surgery. The S-curve incision has a substantially non-planar rectangular ribbon shape with convex and concave curves that yield an S-curve shape. The S-curve incision may be compared with a Z-bend incision, which has bends or corners instead of curves. The S-curve shape may reduce leakage from the incision better than the Z-bend shape and may yield improved wound self-sealing.
In certain embodiments, laser source 110 comprises a laser engine capable of generating beam 101 of femtosecond laser pulses. In certain variants, laser source 110 comprises a chirped pulse amplification (CPA) laser, which may include: an oscillator to generate femtosecond seed pulses; a stretcher to stretch the seed pulses by a factor of 10-1000 to the picosecond range; an amplifier to amplify the pulses; and a compressor to compress the length of the amplified pulses back to the femtosecond range. In certain variants, laser source 110 comprises a cavity-dumped regenerative amplifier laser, which may include: an oscillator, stretcher-compressor, and optical amplifier. Examples of laser source 110 include a bulk laser, fiber laser, or hybrid laser.
In certain variants, the laser pulses generated by laser source 110 may have: a pulse duration in the range of 100 to 600, 600 to 5,000, and/or 5,000 to 10,000 femtoseconds (fs), such as 600 to 1000 fs; a per-pulse energy in the range of 0.1 to 1000 microjoule (μJ), such as 1 to 3 μJ, e.g., approximately 2 μJ; a repetition frequency in the range of 1 kilohertz (kHz) to 1 megahertz (MHz); a spot separation in the range of 0.1 to 10 micrometers (μm), such as 1 to 5 μm, e.g., approximately 3 μm; and a layer separation in the range of 0.1 to 10 micrometers (μm), such as 1 to 5 μm, e.g., approximately 2 μm. Specific laser parameters for a particular procedure may be selected based on the patient or procedure.
Scanners 120 scan beam 101 to direct focus spots 102 of beam 101 towards points of eye 103 to create an incision in eye 103 in response to instructions from laser controller 160. Scanners 120 include any suitable combination of xy-scanner(s) and z-scanner(s). An xy-scanner scans focus spot 102 of beam 101 in an xy-plane perpendicular to an optical axis of the laser system 100, while a z-scanner scans focus spot 102 of beam 101 in the z-direction along the optical axis of laser system 100. Xy-scanners and z-scanners may include steering mirror(s), galvanometer(s), lens(es), servomotor(s), etc.
Optics refers to one or more optical elements that act on (e.g., transmit, reflect, refract, diffract, collimate, condition, shape, focus, modulate, and/or otherwise act on) beam 101. Examples of optical elements include a lens, prism, mirror, diffractive optical element (DOE), holographic optical element (HOE), and a spatial light modulator (SLM). Delivery optics 130 may include a focusing objective lens, a beam expander, a birefringent lens, and other lenses to direct, collimate, condition, and/or focus the scanned beam 101 through patient interface 140 to focus spot 102 of eye 103.
Patient interface 140 may include, for example, a one or two-piece transparent applanation lens attached to a mount on delivery optics 130. The mount can provide a stable connection between the patient interface and delivery optics 130. Patient interface 140 may attach to and immobilize eye 103 during a laser procedure.
System 100 may additionally include one or more imaging devices 150. In certain embodiments, system 100 includes a surgical microscope, video microscope, digital microscope, ophthalmoscope, and/or camera to receive imaging light 104 and generate real-time images of eye 103 during a procedure. System 100 may include enhanced imaging devices to assist in guiding the laser surgery, e.g., an optical coherence tomography (OCT) imaging system to generate depth-resolved images of the inner structure of eye 103, such as the location, position, and curvature of the crystalline lens, the anterior and posterior capsules, and the cornea. Image data 105 generated by imaging device 150 may be provided to a laser controller 160.
Laser controller 160 comprises memory M storing instructions executable by a processor P to control pulsed laser source 110, scanners 120, delivery optics 130, and/or imaging devices 150. Typically, the processor of laser controller 160 comprises one or more CPUs (such as those manufactured by Intel, AMD, and others), microprocessors, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), digital-signal processors (DSPs), or system-on-chip (SoC) processors communicatively coupled to memory. The memory may comprise a non-transitory computer-readable medium, and may include volatile or non-volatile memory including, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), removable media, or analogous components. The memory may store software instructions executable by the processor to generate control signals 106 that control the operation of pulsed laser source 110, scanners 120, delivery optics 130, and/or imaging device 150.
In certain embodiments, laser controller 160 is a computer that generates signals 106 to control parameters of beam 101 generated by pulsed laser source 110, such as a repetition rate, pulse length, and pulse energy. Laser controller 160 may also generate signals 106 to actuate components of scanners 120 and/or delivery optics 130 to direct and focus spots 102 according to a surgical scan pattern to create an incision. Such scan patterns may be any suitable two-dimensional or three-dimensional shape or pattern, including spiral, raster, zig-zag, circular, elliptical, cylindrical, or spider patterns. Raster and zig-zag scan patterns may be described using an xy-coordinate system. The scan patterns scan along parallel lines, e.g., lines of constant y values and parallel to the x-axis. After scanning one line, the scan patterns scans to the next line in the y-direction. A raster pattern scans one line and then the next line in the same x-direction. A zig-zag pattern scans one line in one x-direction and then the next line in the opposite x-direction.
The cross-section of incision 170 in the longer direction exhibits a convex curve and a concave curve. The convex curve is convex relative to anterior corneal surface, and the concave curve is concave relative to anterior corneal surface. The cross-section of incision 170a of
As discussed above, the S-curve incision may be used as, e.g., a primary incision for cataract surgery. A primary incision may receive, e.g., a phacoemulsification handpiece tip to perform a phacoemulsification procedure or an assistance instrument, such as a pick to move cataract pieces toward the handpiece tip. The intraocular pressure (IOP) is typically elevated during the process to reduce the chances that the eye collapses. If an incision is open, the pressure falls below the natural or normal IOP level. The S-curve shape may reduce leakage from the incision better than the Z-bend shape, which may yield improved wound self-sealing. Accordingly, the S-curve may have advantages.
In the illustrated example, normal lines 202 (202a, 202b), layer line 204, and Z-lines 211 (211a-c) are shown to aid in the description of S-curve incision 170. Normal lines 202 and layer line 204 are described relative to structures of the eye, e.g., posterior corneal surface 212 and anterior corneal surface 214. A normal line 202 may be: orthogonal to posterior corneal surface 212 and/or anterior corneal surface 214; or an average of the normal lines of posterior corneal surface 212 and anterior corneal surface 214; or the shortest distance between posterior corneal surface 212 and anterior corneal surface 214.
In the illustrated example, incision 170 intersects posterior corneal surface 212 at point 206a and anterior corneal surface 214 at point 206b. In this example, normal line 202a also intersects posterior corneal surface 212 at point 206a, and normal line 202b also intersects the point of anterior corneal surface 214 at point 206b. In another example, incision 170 might not quite reach posterior corneal surface 212 and/or anterior corneal surface 214. In this example, one or more imaginary extensions of incision 170 may be drawn to intersect posterior corneal surface 212 at point 206a and/or anterior corneal surface 214 at point 206b. Layer line 204 may be the line where the cross-section intersects a plane between posterior corneal surface 212 and anterior corneal surface 214 that is a predetermined distance away from posterior corneal surface 212 and/or anterior corneal surface 214. The distance may be specified by a length and may have any suitable value, e.g., 100 to 150, 150 to 180, 180 to 200, 200 to 220, 220 to 240, 240 to 260, and/or 260 to 300 μm from anterior corneal surface 214 (or from posterior corneal surface 212). Alternatively or additionally, the distance may be specified by a percentage of the corneal thickness and may have any suitable value, e.g., 10 to 20, 20 to 30, 30 to 35, 35 to 40, 40 to 50, 50 to 60 and/or 60 to 70 percent of corneal thickness from anterior corneal surface 214 (or from posterior corneal surface 212).
Z-lines 211 are described relative to normal lines 202. In the illustrated example, posterior Z-line 211a intersects posterior corneal surface 212 at point 206a, with an angle A between normal line 202a and Z-line 211a. Angle A may have any suitable value, e.g., a value in the range of 15 to 90 degrees, such as in the range of 15 to 30, 30 to 45, 45 to 60, 60 to 75, and/or 75 to 90 degrees. Anterior Z-line 211c intersects anterior corneal surface 214 at point 206b, with an angle C between normal line 202b and Z-line 211c. Angle C may have any suitable value, e.g., a value in the range of 15 to 90 degrees, such as in the range of 15 to 30, 30 to 45, 45 to 60, 60 to 75, and/or 75 to 90 degrees. Z-line 211b connects Z-lines 211a and 211c, with an angle B between layer line 204 and Z-line 211b. Z-line 211b has a length L and a midpoint M. Angle B may have any suitable value, e.g., a value in the range of 10 to 20, 20 to 30, 30 to 40, and/or 40 to 50 degrees.
Incision 170 extends from a posterior end 172 to an anterior end 174, which may be located at any suitable part of an eye. In the example, posterior end 172 is located at posterior corneal surface 212 and anterior end 174 is located at anterior corneal surface 214. In other examples, posterior end 172 may be posterior or anterior to posterior corneal surface 212 and/or anterior end 174 may be posterior to anterior corneal surface 214. Incision 170 is substantially tangential to Z-line 211a near posterior corneal surface 212, and is substantially tangential to Z-line 211c near anterior corneal surface 214.
Incision 170 includes convex curve 216 and concave curve 218, and intersects line 211b approximately between convex curve 216 and concave curve 218. In the illustrated example, convex curve 216 is convex relative to anterior corneal surface 214, and concave curve 218 is concave relative to anterior corneal surface 214. Of course, convexity and/or concavity may be described relative to any other suitable structure, e.g., posterior corneal surface 212. Curves 216, 218 may have any suitable dimensions. A curve 216, 218 has an apex height h (h1, h2). Apex height h is the distance between the apex of a curve and line 211b. In the example, convex curve 216 has an apex height h1, and concave curve 218 has an apex height h2. Apex height h may have any suitable value, e.g., a value in the range of up to 20 percent of the corneal thickness (i.e., the thickness between posterior corneal surface 212 and anterior corneal surface 214), e.g., a percentage in the range of 0 to 5, 5 to 8, 8 to 12, 12 to 15, and/or 15 to 20 percent of corneal thickness, such as 10 percent. Distance d is the distance between apex heights h1 and h2, and may have any suitable value, e.g., a value in the range of 30 to 70 percent (such as 30 to 40, 40 to 60, and/or 60 to 70 percent) of the length of a longer side 176.
A computer (such as laser controller 160) creates S-curve incision 170 in the cornea at steps 316 to 322. S-curve incision 170 has a substantially non-planar rectangular shape with a longer side and a shorter side. The longer side extends from posterior end 172 proximate to posterior corneal surface 212 to anterior end 174 proximate to anterior corneal surface 214, and defines a longer direction. The shorter side may be the posterior end 172 and/or anterior end 174. A shorter direction is substantially perpendicular to the longer direction.
The computer creates S-curve incision 170 by controlling delivery optics 130 and scanners 120 to direct and focus the focus spots to perform the following. Posterior end 172 of S-curve incision 170 is created at step 318. A portion of S-curve incision 170 with a convex curve 216 and a concave curve 218 is created at step 320. Convex curve 216 is convex relative to anterior corneal surface 214, and concave curve 218 is concave relative to anterior corneal surface 214. Anterior end 174 of S-curve incision 170 is created at step 322.
S-curve incision 170 at steps 316 to 322 may be formed using any suitable procedure. In certain embodiments, the non-planar rectangular ribbon shape of S-curve incision 170 may be formed starting from posterior end 172 and ending at anterior end 174, where a raster scan or a zig-zag scan is used to generate the focus spots of the ribbon shape. In other embodiments, focus spots may be generated according to depth in the z-direction, where the propagation direction of beam 101 defines the +z-direction, i.e., the +z-direction is parallel to and in the same direction as beam 101. The focus spots of S-curve incision 170 are scanned starting from points with the greatest z-value, e.g., closest to posterior corneal surface 212, continuing through points with the smaller and smaller z-values, and ending at points with the smallest z-value, e.g., closest to anterior corneal surface 214. After creating the S-curve incision 170, the method ends.
A component (such as laser controller 160) of the systems and apparatuses disclosed herein may include an interface, logic, and/or memory, any of which may include hardware and/or software. An interface can receive input to the component, send output from the component, and/or process the input and/or output. Logic can perform operations of the component. Logic may include one or more electronic devices that process data, e.g., execute instructions to generate output from input. Examples of such an electronic device include a computer, processor or microprocessor (e.g., a Central Processing Unit (CPU), and computer chip. Logic may include computer software that encodes instructions capable of being executed by the electronic device to perform operations. Examples of computer software includes a computer program, an application, and an operating system.
A memory can store information and may comprise tangible, computer-readable, and/or computer-executable storage medium. Examples of memory include computer memory (e.g., Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (e.g., a hard disk), removable storage media (e.g., a Compact Disk (CD) or Digital Video or Versatile Disk (DVD)), database and/or network storage (e.g., a server), and/or other computer-readable media. Particular embodiments may be directed to memory encoded with computer software.
Although this disclosure has been described in terms of certain embodiments, modifications (such as changes, substitutions, additions, omissions, and/or other modifications) of the embodiments will be apparent to those skilled in the art. Accordingly, modifications may be made to the embodiments without departing from the scope of the invention. For example, modifications may be made to the systems and apparatuses disclosed herein. The components of the systems and apparatuses may be integrated or separated, or the operations of the systems and apparatuses may be performed by more, fewer, or other components. As another example, modifications may be made to the methods disclosed herein. The methods may include more, fewer, or other steps, and the steps may be performed in any suitable order.
To aid the Patent Office and readers in interpreting the claims, Applicants wish to note that they do not intend any of the claims or claim elements to invoke 35 U.S.C. § 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim. Use of any other term (e.g., “mechanism,” “module,” “device,” “unit,” “component,” “element,” “member,” “apparatus,” “machine,” “system,” “processor,” or “controller”) within a claim is understood by the applicants to refer to structures known to those skilled in the relevant art and is not intended to invoke 35 U.S.C. § 112(f).
| Number | Date | Country | |
|---|---|---|---|
| 63043861 | Jun 2020 | US |
