Laser Guidance Using SLO for the Treatment of Floaters

Abstract

In certain embodiments, an ophthalmic surgical laser system for generating images of and treating eye floaters includes an SLO subsystem, a treatment laser subsystem, a scanner, optics, and a computer. The SLO subsystem provides an SLO laser beam with an SLO focus, and the treatment laser subsystem provides a treatment laser beam with a treatment focus that is spatially coincident with the SLO focus. The scanner scans the SLO laser beam within a scan region and directs the treatment laser beam to an xy location of the scan region. The optics aim the SLO laser beam and the treatment laser beam to substantially the same point on the scan region. The computer receives the SLO image of the floaters, identifies the xy location of the floaters, and commands the treatment laser system to direct the treatment laser beam to the xy and z scan location of the floaters.

Description

[Technical field]

[0001] The present disclosure relates generally to ophthalmic surgical laser systems, and more particularly to laser guidance using confocal SLO for the treatment of floaters. [Background technology]

[0002] Eye floaters are collagen protein clumps that form in the vitreous. These clumps can disrupt vision by casting moving shadows. In laser vitreous lysis, a laser beam is directed into the vitreous to break up eye floaters and improve vision. Summary of the Invention [Means for solving the problem]

[0003] In a particular embodiment, an ophthalmic surgical laser system for treating floaters in the vitreous of an eye includes a scanning laser ophthalmoscope (SLO) subsystem, a therapeutic laser subsystem, a scanner, optics (focusing lens), and a computer. The SLO subsystem includes an SLO laser source and a pinhole filter. The SLO laser source provides an SLO laser beam with an SLO focus, and the pinhole filter is conjugate with the SLO focus. The therapeutic laser subsystem provides a therapeutic laser beam with a therapeutic focus that is spatially coincident with the SLO focus. The scanner scans the SLO laser in the scan region and directs the therapeutic laser beam to an xy position of the scan region. The optics aim the SLO laser beam and the therapeutic laser beam at substantially the same point in the scan region, align the SLO focus to a z-scan position to form the scan region therein, move the scan region to the z-scan position of the floaters, and align the therapeutic focus to the z-scan position of the floaters. The computer receives images of the floater from the SLO subsystem, identifies the xy location of the floater, and commands the treatment laser subsystem to direct a treatment laser beam to the xy and z scan location of the floater.

[0004] Embodiments may include none, one, some, or all of the following features.

[0005] * The optical element moves the scan area in the z-direction by changing the relative distance between the eye and at least one optical element.

[0006] *The optical element moves the scan area in the z-direction by changing the relative distance between the focusing lenses.

[0007] * The ophthalmic surgical laser system includes a tunable lens that moves the SLO focus and the treatment focus. The optical element moves the scan field in the z-direction by adjusting the tunable lens to move the SLO focus and the treatment focus.

[0008] The computer determines the xy location of the floatable object by receiving user input indicating the xy location of the floatable object.

[0009] * The computer determines the xy location of the floatable object by analyzing the image of the floatable object from the SLO subsystem and determining the xy location of the floatable object from the image.

[0010] * The optics move the scan area to the retina of the eye, and the SLO subsystem creates an image of the floater's shadow on the retina.

[0011] * The therapeutic laser subsystem directs the therapeutic laser beam to the xy and z scan location of the suspension by directing laser pulses to the suspension.

[0012] * The therapeutic laser subsystem directs a therapeutic laser beam to the xy and z scan location of the floater by directing laser pulses to the floater to form a three-dimensional volume that covers more than 80% of the floater's volume.

[0013] * The computer analyzes the image of the shadow on the eye's retina from the SLO subsystem and determines whether the shadow is caused by a significant floater.

[0014] * The computer analyzes the image of the floater from the SLO subsystem and determines whether the floater is in focus or not.

[0015] * The computer calculates the floater-retinal distance as a function of changes in the system used to adjust the scan area between the retina and the floater. The computer may calculate the floater-retinal distance as a function of the distance a system component has moved to adjust the scan area between the retina and the floater, or as a function of the difference in diopters used to adjust the scan area between the retina and the floater.

[0016] * The computer calculates the retinal exposure of the therapeutic laser beam focused at the z-scan location of the floater and executes an alarm response if the retinal exposure exceeds a predetermined limit. The computer calculates the retinal exposure EXP as EXP=E / [(L*α) 2 π / 4], where E denotes the laser pulse energy, α denotes the total convergence angle of the treatment laser beam focused on the z-scan position of the floater, and L denotes the floater-retina distance calculated according to the z-position of the floater.

[0017] * A computer uses tracking software to track the movement of the floaters.

[0018] *The SLO subsystem generates images of the eye at different z-scan positions, and a computer generates a 3-dimensional image from these images.

[0019] The system further includes a display, which may be a computer monitor or virtual reality glasses.

[0020] * The wavelength of the therapeutic laser beam ranges from 350 nanometers (nm) to 2000 nm, and the pulse duration of the laser pulse ranges from 20 femtoseconds (fs) to 1000 nanoseconds (ns).

[0021] * The system further includes an ultrasound sensor that monitors the position of the patient's eye and / or head relative to the objective lens.

[0022] In certain embodiments, a method for treating floaters in the vitreous of an eye includes providing, with a scanning laser ophthalmoscope (SLO) subsystem, an SLO laser beam having an SLO focus; providing, with a therapeutic laser subsystem, a therapeutic laser beam having a therapeutic focus, the therapeutic focus spatially coincident with the SLO focus; scanning, with a scanner, the SLO laser within a scan region; aiming, with optics, the SLO laser beam and the therapeutic laser beam at substantially the same point on the scan region; and aligning, with the optics, the SLO focus at a z-scan position. the steps of: forming a scan area therein using a scanner; moving the scan area to the z-position of the floater using an optical element; receiving an image of the floater from the SLO subsystem using a computer; identifying an x-y position of the floater using a computer; instructing the treatment laser subsystem using a computer to direct a treatment laser beam to the x-y and z-scan position of the floater; directing the treatment laser beam to the x-y position of the scan area using a scanner; and focusing a treatment focal point at the z-scan position of the floater using an optical element.

[0023] Embodiments may include none, one, some, or all of the following features.

[0024] The scan area is moved in the z-direction by changing the relative distance between the eye and at least one optical element.

[0025] * The scan area is moved in the z-direction by changing the relative distance between the focusing lenses.

[0026] * The scan field is moved in the z direction by adjusting the tunable lens to move the SLO focus and the therapeutic focus. [Brief description of the drawings]

[0027] [Figure 1A-1B] 1 shows an example of an ophthalmic surgical laser system that can move the scan area to different z positions. [Figure 2A-2C] 4 shows examples of images that can be generated at different z positions. [Diagram 3] 1 illustrates an example of an ophthalmic surgical laser system that may be used to treat floaters in the eye, according to certain embodiments. [Figure 4] 1 illustrates an example of how an ophthalmic surgical laser system can move a scan area, according to certain embodiments. [Diagram 5] 13 illustrates another example of how an ophthalmic surgical laser system can move the scan area, according to certain embodiments. [Figure 6] 13 illustrates yet another example of how an ophthalmic surgical laser system can move the scan area, in accordance with certain embodiments. [Figure 7A-7C] 13 shows example images of floaters generated at different z-scan positions. [Figure 8] 2 illustrates an example of a method for treating floaters that may be performed by the system of FIG. 1, according to certain embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Referring now to the description and drawings, exemplary embodiments of the disclosed apparatus, 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 figures and disclosed in the description. While the drawings illustrate possible embodiments, the drawings are not necessarily to scale and certain features may be simplified, exaggerated, omitted, or truncated in order to better illustrate the embodiments.

[0029] In certain laser vitreolysis, an OCT device is used to provide the z-position of the floater and guide the therapeutic laser beam to the floater. However, the OCT device is complex and expensive. Therefore, the embodiments described herein do not use an OCT device to provide the z-position of the floater.

[0030] An example system described herein provides a scanning laser ophthalmoscope (SLO) laser beam for generating an SLO image of floaters or retinal floater shadows, and a therapeutic laser beam for disrupting floaters. The system collimates and aligns both the SLO and therapeutic laser beams, so that they are focused and aimed at substantially the same location in the eye. In an embodiment, the focus of the SLO laser beam can be moved in the z direction to image the floaters themselves. When the image of the floaters is focused, the therapeutic beam is also focused on the floaters because the SLO and therapeutic focal points are aimed at the same location. Therefore, the SLO device can be used to direct the therapeutic beam to the z location of the floaters without utilizing an OCT device.

[0031] 1. Examples of surgical systems 1A and 1B show an example of an ophthalmic surgical laser system 10 where the scan area 12 can be moved, for example, from the retina to the floaters, and FIGS. 2A and 2B show examples of SLO images that can be generated at different z positions. The scan area 12 is the focal plane that indicates where the SLO and treatment laser beams are focused. In this example, the z position of the scan area 12 can be described as a "z scan position." For example, the z scan position of the scan area 12 in FIG. 1A is at the retina, and the z scan area of ​​the scan area 12 in FIG. 1A is at the floaters.

[0032] In Figures 1A and 2A, the scan area 12 is positioned at the retina. Figure 2A shows the shadows S1 and S2 that floaters cast on the retina. In Figures 1B, 2B, and 2C, the scan area 12 is positioned at the floater F1.

[0033] In FIG. 2B, the scan area 12 is positioned at floater F1, so that floater F1 appears as a bright, sharp, two-dimensional enface object moving in the image frame. Floater F2 is nearby but the SLO beam is not focused on it, so it is darker and blurred than floater F1. In general, the shape of a floater should be similar to the shape of its corresponding floater shadow. Artifact A1 is the first Purkinje image due to reflection from the anterior surface of the cornea. Artifact A1 includes diffraction fringes around the edge of the first Purkinje image. Artifact A2 is due to reflections from optical components (such as L1, L2, L3, L4, and / or L5).

[0034] In Fig. 2C, floater F1 is a large diffuse floater on which the SLO beam is focused. The scan area 12 is positioned at floater F1 so that floater F1 appears as a bright, sharp, two-dimensional enface object moving within the image frame. As mentioned before, artifact A1 is the first Purkinje image and artifact A2 is due to reflections from optical components.

[0035] 3 illustrates an example of an ophthalmic surgical laser system 10 that may be used to image and treat floaters in the eye, according to certain embodiments. In overview, system 10 includes a scanning laser ophthalmoscope (SLO) subsystem 20, a therapeutic laser subsystem 22, one or more shared components 24, and a computer 26, coupled as shown. The SLO subsystem includes a laser source (e.g., laser diode 30), optics (such as lenses L3, L4, and / or L5 and beam splitters BS1 and BS2), a pinhole filter PH, and a PIN diode 32, coupled as shown. Shared components 24 include a scanner (e.g., an xy or 2D scanner) 40, an xy encoder 42, and optics (such as focusing lenses L1 and L2, where L2 may be an objective lens), coupled as shown. Computer 26 includes logic 50, memory 52 (storing computer programs 54), and a display 56, coupled as shown. System 10 may include sensors (e.g., ultrasound sensors) that monitor the position of the patient's eye and / or head relative to the system components (e.g., objective lens L2). In general, optical elements may act on (e.g., transmit, reflect, refract, diffract, collimate, condition, shape, focus, modulate, and / or otherwise act on) the laser beam.

[0036] According to an overview of an example of imaging, for example, of the retina or floaters, the SLO laser source (e.g., laser diode 30) of the SLO subsystem 20 provides an SLO laser beam having an SLO focus. Lens L4 collimates the SLO laser beam. The SLO laser beam passes through beam splitters BS1 and BS2, is deflected by the scanner 40, passes through lenses L1 and L2 (and L5 in certain embodiments), and is focused, for example, on the retina or floaters. That is, beam splitter BS1 transmits the SLO laser beam toward beam splitter BS2, which transmits the beam toward scanner 40. (In certain embodiments, tunable lens L5 transmits the SLO laser beam.) Scanner 40 scans the SLO laser beam over a scan area in the eye. Focusing lenses L1 and L2 image scanner 40 to the pupil to focus the SLO and therapeutic laser beams to a common focus and reflect light to form a scan area, for example, at the z-scan position of the retina or floaters. In this way, a large angular range of the retina can be scanned by the SLO beam.

[0037] Continuing with this exemplary overview, the reflected light passes back through lenses L1, L2, scanner 40, (lens L5 in a specific embodiment), and beam splitter BS2. Beam splitter BS1 directs the reflected beam to lens L3, which focuses the beam onto a confocal pinhole filter PH. Pinhole filter PH directs the beam onto PIN diode 32. The position of pinhole filter PH is optically conjugate with the focal point of the SLO laser beam, such that only light reflected back from the focal point of the SLO beam is detected by PIN diode 32; all other back reflections are suppressed by pinhole filter PH. PIN diode 32 outputs a signal proportional to the intensity of the detected light, which can be used to generate an image of the floater.

[0038] Continuing with this exemplary overview, computer 26 collects the signal from PIN diode 32 and the angular deviation of the beam from xy encoder 42, and generates an image of the reflected light in response to the xy readings from xy encoder 42. When system 10 is taking an image of and treating floaters in the vitreous, the optics are positioned to aim the SLO and treatment laser beams at the z-position of the floater. The image of the floater is sharper and brighter, while the background is darker, because the pinhole filter allows the backscattered light from the floater to pass through PIN diode 32, while the backscattered light from the retina is suppressed. Computer 26 determines the xy-position of the floater and commands treatment laser subsystem 22 to generate a treatment laser beam and scanner 40 to aim the beam at the xy-position of the floater. Beam splitter BS1 directs the treatment laser beam to the optics, which directs the beam to the z-scan position of the floater to destroy it.

[0039] Turning to the parts of the system, the SLO subsystem 20 uses confocal laser scanning to generate an image of the inside of the eye. The SLO subsystem 20 moves the scan area 12 of the SLO focus in the z-direction to collect light at different z-scan positions, for example from the retina through the vitreous. A pinhole filter PH is optically conjugate with the SLO focus, so that only light from the SLO focus is detected by the PIN diode 32 and other light (e.g., reflections from the cornea or lens) is suppressed. The SLO subsystem 20 generates an SLO image by plotting the intensity of the back-reflected light as a function of the xy position of the focus.

[0040] The therapeutic laser subsystem 22 generates a laser beam of any suitable wavelength, for example, in the range of 350 nm to 2000 nm. The therapeutic laser subsystem 22 delivers laser pulses of any suitable repetition rate (e.g., single pulses up to 200 megahertz (MHz)). The laser pulses have any suitable pulse duration (e.g., 20 femtoseconds (fs) to 1000 nanoseconds (ns)), any suitable pulse energy (e.g., 1 nanojoule (nJ) to 10 millijoules (mJ) or energies above the optical breakdown threshold of the vitreous), and any suitable size (e.g., 1 to 30 microns (μm)) of focal spot. The therapeutic laser beam is spatially coincident with the collimated SLO beam, such that the focal spots of the SLO beam and the therapeutic laser beam are precisely spatially coincident, i.e., the beams are focused to the same spot.

[0041] In certain embodiments, the therapeutic laser subsystem 22 directs laser pulses at the floater to destroy the floater. In other embodiments, the therapeutic laser subsystem 22 directs multiple laser pulses to form a three-dimensional (3D) volume. The geometric center of the 3D volume may be substantially aligned with the geometric center of the floater, and the 3D volume may cover all or nearly all, e.g., 80% or more, of the volume of the floater. In this embodiment, the scanner 40 causes the pulses to scan in the xy directions, while, for example, the tunable lens L5 scans the focal point in the z direction.

[0042] A shared component 24 directs the beams from the SLO subsystem 20 and the therapeutic laser subsystem 22 to the eye. Because the SLO and laser beams share component 24, they are subject to the same geometric distortions (e.g., scanner fan distortion, scanner lens barrel or pillow distortion, refractive distortion from the inner surface of the eye, and other distortions). Because the distortions affect these beams in the same way, they propagate along the same path. This allows for precise targeting of the laser beam at the floater. Shared component 24 may also perform spectral and / or polarization combining and / or separating of the SLO and laser beams to allow them to share the same path.

[0043] Turning to the details of shared components 24, scanner 40 may be any suitable xy-scanner that varies the angle of incidence of the beam on the pupil to angularly steer the focal point of the beam in the x and y directions. Scanner 40 may include, for example, a pair of scanner mirrors rotated by galvanometer motors that can be tilted about mutually orthogonal axes, an acousto-optic crystal that can steer the beam acousto-optically, and / or a high-speed scanner (e.g., galvano, resonant, or acousto-optic scanner) that can, for example, create a two-dimensional matrix of laser spots of the therapeutic laser beam.

[0044] The xy encoder 42 detects the angular position of the xy scanner 40 and reports the position as an xy position measured in encoder units, e.g., units of degrees. For example, the xy encoder 42 detects the angular orientation of the galvanometer mirrors of the xy scanner 40 and records this orientation in encoder units. The xy encoder 42 may report the position in the encoder units to the SLO subsystem 20, the therapeutic laser subsystem 22, and / or the computer 26. Because both the SLO subsystem 20 and the therapeutic laser subsystem 22 share the same xy scanner 40, the computer 26 can use the encoder units to command the subsystems 20, 22 where to aim their beams, thereby avoiding the need to perform computer-intensive conversions from the encoder units to units of length, such as millimeters. The xy encoder 42 reports its position at any suitable rate, e.g., once every 5-50 milliseconds (ms), e.g., once every 10-30 ms, or about once every 20 ms.

[0045] Lenses L1 and L2 image the scanner 40 into the pupil, allowing the SLO and treatment laser beams to scan a wide range of angles. Lenses L1 and L2 may include any suitable number of lenses arranged to image the scanner 40 into the pupil while allowing the system 10 to vary the convergence angle (e.g., number of diopters) of the beams entering the pupil. Increasing the diopter may shift the focus of the SLO beam into the vitreous.

[0046] Computer 26 controls the components of system 10 (e.g., SLO subsystem 20, laser device 24, and / or shared components 24) in accordance with computer program 54. Computer 26 may be separate from the components or may be distributed in any suitable manner within system 10, such as within SLO subsystem 20, laser device 24, and / or shared components 24. In certain embodiments, the portions of computer 26 that control SLO subsystem 20, laser device 24, and / or shared components 24 may be part of SLO subsystem 20, laser device 24, and / or shared components 24, respectively.

[0047] Computer 26 controls the components of system 10 according to computer programs 54. Examples of computer programs 54 include object imaging, object tracking, image processing, image analysis, floater assessment, and retinal exposure calculation programs. For example, computer 26 uses computer programs 54 to instruct SLO subsystem 20, laser device 24, and / or shared components 24 to move a scan region to the floater so that the SLO and treatment focal points are aligned with the floater, generate an image of the floater, identify the xy location of the floater, and / or direct a treatment laser beam to the floater.

[0048] In certain embodiments, computer 26 analyzes the digital information of the image using image analysis program 54. For example, computer 26 may analyze the image, for example using edge detection or pixel analysis, to look for features that may be floaters and to distinguish floaters from non-floater images. Computer 26 may identify darker features on the retina that move with the vasculature as floater shadows and lighter features in the vitreous as floaters. Opacities that move with the vasculature may be recognized by computer 26 as retinal anatomical opacities rather than floaters.

[0049] In addition, computer 26 may recognize certain images as artifacts, as shown in Figures 2B and 2C. A large bright patch with diffraction fringes around its edges that moves in the opposite direction of the SLO image in the display frame (e.g., downward as the image moves upward in the display frame, or left as the image moves right) may be a first Purkinje image, as shown as artifact A1 in Figures 2B and 2C. A bright spot that does not move with respect to the SLO display frame may be an internal reflection from an optical component (such as L1, L2, L3, L4, and / or L5), as shown as artifact A2 in Figures 2B and 2C.

[0050] As another example of using the image analysis program 54, the computer 26 analyzes an image of a floater shadow to determine whether the shadow is produced by a significant floater, e.g., a clinically significant floater that should be treated. The shape and size of the floater shadow indicates the size and shape of the floater, and the color or brightness of the floater shadow indicates the density of the floater. As another example, the computer 26 analyzes an image of a floater to determine whether the SLO focus is on the floater. If the edge of the floater is sharp, i.e., the floater is in focus, the focus is on or near the floater. If the image of the floater is brightest and sharpest when focusing the SLO beam in the z-direction, the floater is in focus.

[0051] In certain embodiments, computer 26 generates an image for presentation on display 56. For example, computer 26 presents multiple sequential images as a movie. As another example, computer 26 combines multiple SLO images taken at different z-scan positions into a three-dimensional (3D) image. This 3D image can be used to identify the spatial size and location of an array of laser treatment pulses used to treat floaters.

[0052] In certain embodiments, computer 26 identifies the xy location of the floater. For example, computer 26 may receive user input indicating the xy location of the floater. The user may select an xy location on the displayed image that corresponds to the floater's location, for example by touching the xy location on the screen or selecting the xy location with a cursor, and input the xy location. In other embodiments, computer 26 performs image analysis on the SLO image to identify the xy location of the floater. Computer 26 may identify the floater in the image and then identify the xy location from its location in the image. Once computer 26 identifies the xy location of the floater, computer 26 may instruct scanner 40 to direct a treatment beam to the floater's location in encoder units.

[0053] In certain embodiments, computer 26 calculates the exposure on the retina from a laser pulse directed to a location, e.g., the location of a floater, and executes an alarm response if the retinal exposure exceeds a predetermined limit. For example, the retinal exposure EXP can be calculated as EXP=[E / (L*α) 2 π / 4], where E is the energy of the laser pulse, α is the total convergence angle of the laser beam in the vitreous focused on the location of the floaters, and L is the distance to the retina, e.g., the floater-retina distance, which can be calculated as described below. The exposure should be less than the maximum exposure that can be specified according to an acceptable standard. For example, the maximum exposure can be set according to ANSI Z80.36-2016 "Maximum Exposure Permitted" (ANSI MPE). If the exposure exceeds the maximum exposure, e.g., the ANSI MPE, computer 26 can execute an alarm response, such as modifying any appropriate element (e.g., reducing the pulse energy), providing a notification to the user, and / or preventing the laser beam from firing. Computer 26 can also calculate an exposure ratio R=EXP / [ANSI MPE] and provide the ratio R to a user (e.g., a surgeon) to enable the user to specify whether or not to treat the floaters.

[0054] Display 56 may be any suitable hardware capable of displaying an image. Examples of display 56 include a computer monitor and virtual reality glasses. A user (e.g., a surgeon or other medical personnel) in the operating room or remote from the operating room may view the computer-generated images.

[0055] Involuntary and voluntary eye movements (e.g., saccades and microsaccades, drift, and tremors) can make laser treatment difficult. To reduce eye movements, the eye may be stabilized. For example, the treatment eye and / or the contralateral eye may be stabilized using a fixation light. If the xy position of the fixation light can be moved up to 25 degrees in any angular direction, floaters due to their location away from the visual axis can be treated. As another example, the eye may be mechanically stabilized using a patient interface or handheld surgical contact lens. The interface or lens may have a spherical contact surface that reduces the refractive errors of the eye, such as corneal astigmatism and asphericity of the eye. As another example, the movement of the floaters may be tracked by tracking software, and the focus of the treatment laser may be constantly aimed at the moving floaters.

[0056] 2. Examples of moving focal points 4-6 show an embodiment of an ophthalmic surgical laser system 10 capable of moving the image and therapeutic focal point in the z-direction, and FIGS. 8A-8C show example images taken at different z-scan positions. In certain embodiments, components of the system 10 are adjusted (e.g., moved, reshaped, or otherwise modulated) to move the scan region 12. The components may be adjusted in any suitable manner. For example, a mechanical structure may apply a force in response to a user's action to move the components, a motorized actuator may move the components, and / or an electric current may reshape or otherwise modulate a tunable lens. The movement may be initiated, for example, in response to a user moving a controller (e.g., a knob) and / or in response to a command from the computer 26.

[0057] From the changes made by the system 10 to adjust the scan area 12 from the retina to the floaters, the computer 26 can calculate the distance between the retina and the floaters (the "floater-retina distance"). For example, the floater-retina distance can be calculated from the distance a component of the system 10 has moved to adjust the scan area 12 or the difference in diopters required to adjust the scan area 12, as described in more detail below. The computer 26 can calculate the distance using a mathematical function or lookup table that describes the relationship between the floater-retina distance and the changes in the system (e.g., between the floater-retina distance and the distance a component has moved to adjust the scan area 12 or between the floater-retina distance and the difference in diopters required to adjust the scan area 12). The function or lookup table can be generated in any suitable manner. For example, during calibration or manufacturing of the system 10, z-scan positions can be recorded for different component positions or diopters, and a function or table can be determined from the results. As another example, the function or table may be determined from an eye model, such as the Zemax eye model. In certain embodiments, the floater-to-retina distance may be used to calculate the amount of retinal exposure that may be received from a laser beam directed at the floater, as described above.

[0058] FIG. 4 shows an example of how the ophthalmic surgical laser system 10 according to certain embodiments can move the scan region 12. In these embodiments, the computer 26 or a user moves the scan region 12 by moving the optics generating the scan region 12, e.g., the SLO subsystem 20, the therapeutic laser subsystem 22, and / or the shared components 24 (e.g., the scanner 40 and the focusing lenses L1, L2, etc.) relative to the eye. The components may be mechanically coupled, so that they move together in the z direction relative to a base of the system 10, e.g., a table base. In these embodiments, the eye is stabilized relative to the base, so that the movement of the components relative to the base (i.e., the change in z position) represents the movement M relative to the eye. The linear encoder 42 may record the relative movement M and report the relative movement M to the computer 26 in units of the encoder.

[0059] In certain embodiments, computer 26 calculates floater-to-retina distance F from the relative movement M. For example, each unit of relative movement M changes the z-scan position of scan region 12 by n units, where n is the refractive index of the vitreous, 1.34. Therefore, floater-to-retina distance F is approximately F=1.34×M. As another example, during calibration of system 10, z-scan positions are recorded for different positions of the moving components, and a function or table is calculated from the results. Computer 26 uses this function or table to calculate floater-to-retina distance F.

[0060] 5 illustrates another example of how the ophthalmic surgical laser system 10 according to certain embodiments can move the scan region 12. In certain embodiments, the computer 26 moves the scan region by changing the relative distance between the focusing lenses L1 and L2 to move the SLO and therapeutic laser focal points.

[0061] In certain embodiments, the system 10 accounts for this change as a change in diopters D. In these embodiments, the computer 26 calculates the floater-retina distance F from the diopter change ΔD. For example, in an average human eye, a +1 diopter change ΔD in the convergence of the laser beam corresponds to a shift of the scan area 12 from the retina of F=0.36 mm. Therefore, the floater-retina distance F=0.36×ΔD mm. The multiplier of 0.36 is valid near the retina, for longer distances a look-up table or mathematical function can be generated as described above.

[0062] FIG. 6 shows another example of how the ophthalmic surgical laser system 10 according to certain embodiments can move the scan area 12. In certain embodiments, the system 10 includes a tunable lens L5 that moves the SLO and therapeutic laser focal point in the z-direction. In these embodiments, the computer 26 moves the scan area by adjusting the tunable lens L5 to convert the collimated laser beam into a focused laser beam that forms a focal point. The tunable lens L5 can be any suitable lens or arrangement of lenses. For example, the tunable lens L5 can be an electrically tunable lens, which can achieve fast scanning of the focal point. As another example, the tunable lens L5 can be a compound lens including two or more lenses. By adjusting the distance between the lenses, the equivalent refractive power changes. In certain embodiments, the system 10 accounts for this adjustment as a change in diopter D, and the computer 26 calculates the floater-retina distance F from the change in diopter ΔD, as described above.

[0063] 7A-7C show example images of the same floater that can be generated at different z-scan positions. In the images, different parts of the floater are in focus at different z-scan positions. FIG. 7A shows a scan area at 18.6D, or 6.7mm, from the retina, with the floater in focus to the right. FIG. 7B shows a scan area at 21.2D, or 7.6mm, with the floater in focus in the center. FIG. 7C shows a scan area at 28.2D, or 10.1mm, with the floater in focus to the left.

[0064] 3. Method Example 8 illustrates an example of a method for treating floaters that may be performed by the system 10 of FIG. 1, according to certain embodiments. Certain steps of the method may be performed by a computer of the system that instructs system components to perform those steps. During execution of the method in certain embodiments, the computer may calculate a retinal exposure of the therapeutic laser beam on the retina. If the retinal exposure exceeds a predetermined limit, the computer may execute an alarm response (e.g., notify a user and / or stop treatment).

[0065] The method begins at step 110, where a scan area is placed on the retina to generate an SLO image of the floater shadow on the retina. The computer or user may adjust (e.g., move) the optical element generating the scan area to place the scan area on the retina. The scanner of the system may perform an angular scan, for example, greater than 45 degrees, around the visual axis to detect the floater shadow. At step 112, floaters to be treated are identified. In certain embodiments, the computer may analyze the image of the floater shadow to identify whether the floater can be evaluated as clinically significant or not, for example, depending on the size, density, and / or xy location of the floater shadow. In other embodiments, a user (e.g., a surgeon) may identify whether the floater is significant or not.

[0066] In step 114, the scan area is moved to the floater and the SLO and the treatment laser beam are aimed at the z-scan position of the floater. The computer or the user can adjust the optical elements that generate the scan area to move the scan area. The adjustment of the optical elements can be performed, for example, by moving one or more of the optical elements, by changing the relative distance between the focusing lenses of the focus, and / or by adjusting the tunable lens that moves the focus. When the scan area is at the floater, the image of the floater is bright and sharp because the SLO and the treatment laser beam are focused on the floater. The brightness and sharpness can be evaluated by the user or by the computer using an image analysis program.

[0067] The floaters are in focus. In certain embodiments, a computer may analyze the image of the floaters to determine whether the floaters are in focus. In other embodiments, a user may determine whether the floaters are in focus.

[0068] At step 116, the SLO subsystem generates an SLO height of the floater. In certain embodiments, the SLO subsystem generates multiple images at different z positions, and the computer generates a three-dimensional image from the multiple images. At step 120, the computer determines the xy position of the floater. The xy position may be determined by analyzing the SLO images of the floater in the vitreous.

[0069] In step 122, the therapeutic laser subsystem directs a therapeutic laser beam to the floater. For example, the therapeutic laser subsystem directs a laser pulse to the floater. As another example, the therapeutic laser subsystem directs a laser pulse that forms a three-dimensional volume. The therapeutic laser subsystem substantially aligns the geometric center of the three-dimensional volume with the geometric center of the floater. In step 124, the user may wish to check for further floaters. If so, the method returns to step 110, where the scan area is placed on the retina to generate an SLO image of the retina, and check for any further floater shadows that would indicate the presence of floaters. If not, the method ends.

[0070] Components of the systems and devices disclosed herein (such as control computer 26) may include interfaces, logic, and / or memory, any of which may include computer hardware and / or software. An interface may receive input to and / or transmit output from a component and is typically used to exchange information between, for example, software, hardware, peripherals, users, and combinations thereof. A user interface is one type of interface that a user can use to communicate with a computer (e.g., send input to and / or receive output from). Examples of user interfaces include a display, a graphical user interface (GUI), a touch screen, a keyboard, a mouse, a gesture sensor, a microphone, and a speaker.

[0071] Logic can perform the operations of a component. Logic can include one or more electronic devices that execute instructions to process data, e.g., generate output from input. Examples of such electronic devices include computers, processors, microprocessors (e.g., central processing units (CPUs)), and computer chips. Logic includes computer software that encodes instructions executable by an electronic device to perform operations. Examples of computer software include computer programs, applications, and operating systems.

[0072] A memory may store information and may include a 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., hard disks), removable storage media (e.g., compact discs (CDs) or digital video or versatile discs (DVDs)), databases, network storage (e.g., servers), and / or other computer-readable media. Certain embodiments may relate to memory encoded with computer software.

[0073] Although the present disclosure has been described with respect to certain embodiments, modifications of these embodiments (e.g., changes, substitutions, additions, omissions, and / or other modifications) will be apparent to those skilled in the art. Thus, 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 devices disclosed herein. Components of the systems and devices may be integrated or separated, or operations of the systems and devices may be performed by more, fewer, or other components, as would be apparent to one skilled in the art. As another example, modifications may be made to the methods disclosed herein. Methods may include more, fewer, or other steps, and steps may be performed in any suitable order, as would be apparent to one skilled in the art.

[0074] To assist the Patent Office and readers in interpreting the claims, applicant specifies that it is not intended that any of the claims or claim elements be subject to 35 U.S.C. 112(f) unless the terms "means for" or "step for" are expressly used in a particular claim. Any other terms in the claims (e.g., "mechanism," "module," "device," "unit," "component," "element," "member," "apparatus," "machine," "system," "processor," or "controller") are understood by applicant to refer to structures known to those of ordinary skill in the art and are not intended to be subject to 35 U.S.C. 112(f).

Claims

1. 1. An ophthalmic surgical laser system for treating floaters in the vitreous of an eye, the eye having a retina, the ophthalmic surgical laser system comprising:

1. A scanning laser ophthalmoscope (SLO) subsystem, comprising: an SLO laser source configured to provide an SLO laser beam having an SLO focus; A pinhole filter conjugate with the SLO focus; a scanning laser ophthalmoscope (SLO) subsystem including: a therapeutic laser subsystem configured to provide a therapeutic laser beam having a therapeutic focal point, the therapeutic focal point spatially coincident with the SLO focal point; 1. A scanner comprising: Scanning the SLO laser beam within a scan region; Directing the treatment laser beam to an xy location of the scan area. A scanner configured as follows: A plurality of optical elements including a plurality of focusing lenses, aiming the SLO laser beam and the treatment laser beam at substantially the same point on the scan area; aligning the SLO focus to a z-scan position to form the scan region thereat; moving the scan region in a z-direction to the z-scan position of the suspension; Aligning the therapeutic focal spot with the z-scan position of the floater A plurality of optical elements configured as above; A computer comprising: receiving an image of the floating object from the SLO subsystem; Identifying the xy position of the floater; commanding the therapeutic laser subsystem to direct the therapeutic laser beam to the xy and z-scan location of the floater; A computer configured as follows:

1. An ophthalmic surgical laser system comprising:

2. The optical element is Varying the relative distance between the eye and at least one of the plurality of optical elements. The ophthalmic surgical laser system of claim 1 , configured to move the scan region in the z-direction by

3. The optical element is Varying the relative distance between the plurality of focusing lenses 2. The ophthalmic surgical laser system of claim 1, configured to move the scan region in the z-direction by:

4. The optical element is a tunable lens configured to move the SLO focal point and the therapeutic focal point; and moving the scan region in the z-direction by adjusting the tunable lens to move the SLO focal point and the therapeutic focal point in the z-direction.

10. The ophthalmic surgical laser system of claim 1.

5. The computer includes: receiving user input indicating the xy position of the floater; The ophthalmic surgical laser system of claim 1 , configured to direct the SLO focal point to the xy location of the floater by:

6. The computer includes: Analyzing the image of the floatable object from the SLO subsystem; Identifying the xy position of the floating object from the image. The ophthalmic surgical laser system of claim 1 , configured to identify the xy location of the floater by:

7. the optical element is configured to move the scan area to the retina of the eye; the SLO subsystem is configured to generate an image of the shadow of the floater on the retina; 10. The ophthalmic surgical laser system of claim 1.

8. the therapeutic laser subsystem comprising: Directing a plurality of laser pulses toward the suspension.

2. The ophthalmic surgical laser system of claim 1, configured to direct the treatment laser beam to the xy and z scan positions of the floater by:

9. the therapeutic laser subsystem comprising: Directing a plurality of laser pulses at the suspension, the plurality of laser pulses forming a three-dimensional volume, the three-dimensional volume covering at least 80% of a volume of the suspension.

2. The ophthalmic surgical laser system of claim 1, configured to direct the treatment laser beam towards the xy and z scan positions of the floater by:

10. The computer includes: analyzing an image of a shadow on the retina of the eye from the SLO subsystem; Identifying whether the shadow is a significant floater shadow 2. The ophthalmic surgical laser system of claim 1 , configured to:

11. The computer includes: Analyzing an image of the float from the SLO subsystem; Identifying whether the floater is in focus 2. The ophthalmic surgical laser system of claim 1 , configured to:

12. The computer includes: Calculating the floater-to-retina distance in response to changes in the ophthalmic surgical laser system used to adjust the scan area between the retina and the floater.

2. The ophthalmic surgical laser system of claim 1 , configured to:

13. The computer includes: Calculating the floater-to-retina distance according to the distances that a plurality of system components are moved to adjust the scan area between the retina and the floater.

13. The ophthalmic surgical laser system of claim 12 configured to:

14. The computer includes: Calculate the floater-retina distance according to the difference in diopters used to adjust the scan area between the retina and the floater.

13. The ophthalmic surgical laser system of claim 12, configured as follows:

15. The computer includes: calculating a retinal exposure of the treatment laser beam focused at the z-scan location of the floater; Executing an alarm response if the retinal exposure exceeds a predetermined limit 2. The ophthalmic surgical laser system of claim 1 , configured to:

16. The computer calculates the retinal exposure EXP as EXP=E / [(L*α) ２ 16. The ophthalmic surgical laser system of claim 15, configured to calculate the floater-to-retina distance according to [π / 4], where E represents the energy of the laser pulse, α represents the total convergence angle of the treatment laser beam focused on the z-scan position of the floater, and L represents the floater-to-retina distance calculated according to the z-scan position of the floater.

17. The ophthalmic surgical laser system of claim 1 , wherein the computer is configured to track the movement of the floaters using tracking software.

18. the SLO subsystem is configured to generate a plurality of images of the eye at different z-scan positions; the computer is configured to generate a three-dimensional image from the plurality of images.

10. The ophthalmic surgical laser system of claim 1.

19. The ophthalmic surgical laser system of claim 1 , further comprising a display, said display comprising a computer monitor or virtual reality glasses.

20. 2. The ophthalmic surgical laser system of claim 1, wherein the wavelength of the treatment laser beam is in the range of 350 nanometers (nm) to 2000 nm and the pulse duration of the laser pulse is in the range of 20 femtoseconds (fs) to 1000 nanoseconds (ns).

21. The ophthalmic surgical laser system of claim 1 , further comprising an ultrasonic sensor configured to monitor a position of the eye relative to an objective lens of the plurality of optical elements.

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