Gonioscopic laser surgery

Abstract

To provide gonioscopic laser surgery.SOLUTION: An apparatus for medical treatment includes a gonioscope having a distal face for placement in proximity to a patient's eye, a proximal face opposite the distal face, and multiple facets between the distal and proximal faces. The apparatus also includes: a laser to generate a beam; a scanner to direct the beam through the proximal face of the gonioscope to reflect from a facet into an anterior chamber of the eye; at least one slit lamp to project sheets of light into the eye through the gonioscope; and a camera to capture, through the gonioscope, an image of an illumination pattern cast on the eye by the sheet of light. A processor processes the image so as to identify a location of an anatomical structure in the eye, selects targets in the eye based on the identified location, and controls the scanner so that the beam impinges on the targets.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of International Patent Application No. PCT / IB2023 / 060104, filed October 9, 2023, which claims the benefit of U.S. Provisional Patent Application No. 63 / 414,919, filed October 11, 2022. Both of these related applications are incorporated herein by reference.

[0002] The present invention relates generally to devices and methods for ocular treatment, and more particularly to laser cavernosoplasty. [Background technology]

[0003] Glaucoma is a group of eye diseases that results in damage to the optic nerve. This damage is often caused by elevated intraocular pressure (IOP) in the aqueous humor in the anterior chamber of the eye. This elevated IOP can cause vision loss if left untreated.

[0004] One treatment used to lower IOP is selective laser cavernoscopy (SLT), which is described, for example, in (Non-Patent Document 1). In SLT, multiple laser shots are fired through the anterior chamber into the spongy retina of the eye using a gonioscope. Laser irradiation of the spongy retina improves drainage of aqueous humor through the retina and alleviates the buildup of IOP in the eye.

[0005] The term "optical radiation" is used in this specification and claims to refer to electromagnetic radiation in any of the visible, infrared, and ultraviolet ranges of the spectrum. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Gazzard et al.in“Selective laser trabeculoplasty versus drops for newly diagnosed ocular hypertension and glaucoma:the LiGHT RCT”(NHS,volume 23,issue 31,June 2019,ISSN 1366-5278) Summary of the Invention [Means for solving the problem]

[0007] The embodiments of the present invention described below provide improved devices and procedures for selective laser cavernosoplasty.

[0008] Thus, according to one embodiment of the present invention, there is provided an apparatus for a medical procedure, the apparatus including a gonioscop having a distal surface configured for placement adjacent to a patient's eye, a proximal surface opposite the distal surface, and a number of facets extending between the distal and proximal surfaces, a camera configured to capture an image of the anterior chamber of the eye through the proximal surface of the gonioscop, and a laser configured to generate a beam of optical radiation. The apparatus further includes a scanner configured to direct a beam through the proximal surface of the gonioscop such that the beam reflects off the facets of the gonioscop into the anterior chamber and strikes tissue within the anterior chamber, and optics configured to focus the beam to strike tissue within the anterior chamber with a cone angle of 2° or less. The controller is configured to process the image of the anterior chamber to identify a locus of the spongy retina of the eye, and control the scanner to direct the beam to strike the identified locus at a number of locations around the anterior chamber.

[0009] In the disclosed embodiment, the optics are configured to focus the beam to a cone angle of less than 1.5°.

[0010] In a further embodiment, the camera has a depth of field sufficient to image the entire circumference of the anterior chamber via a gonioscopic view at a fixed focus setting. Typically, the optical system is configured to direct the beam to impinge on multiple locations all around the circumference of the anterior chamber at a fixed focus setting. Alternatively or additionally, the depth of field of the camera is at least 4 mm. Still alternatively, the depth of field is at least 3 mm, 2 mm, or 1 mm.

[0011] In yet another embodiment, in an image captured by the camera, the periphery of the anterior chamber is divided into a number of segments by reflection of portions of the image from a number of facets of the gonioscopic scope, and the processor is configured to stitch the multiple segments together to generate an output image in which the locus of the cavernous retina appears as a continuous band.

[0012] In a disclosed embodiment, the distal face of the gonioscop includes a concave surface configured to contact the cornea of ​​the eye. The device may include a suction ring surrounding the gonioscop and configured to maintain stable contact between the eye and the gonioscop.

[0013] Also, in accordance with one embodiment of the present invention, there is provided a method for a medical procedure, comprising: positioning a distal face of a gonioscopic device proximate to a patient's eye, capturing an image of the anterior chamber of the eye via the gonioscopic device, processing the image of the anterior chamber to identify a locus of the spongy retina of the eye, and directing a beam of optical radiation emitted by a laser through a proximal face of the gonioscopic device such that the beam reflects off a facet of the gonioscopic device into the anterior chamber to impact the identified locus in the anterior chamber at a plurality of locations around the periphery of the anterior chamber, while focusing the beam to impact tissue within the anterior chamber with a cone angle of 2° or less.

[0014] Additionally, in accordance with an embodiment of the present invention, a method for a medical procedure is provided, the method including positioning a distal surface of a gonioscopic device proximate to a patient's eye and capturing an image of the anterior chamber of the eye via the gonioscopic device. The image of the anterior chamber is processed to identify a trajectory of the spongy retina of the eye. A beam of optical radiation emitted by a laser is directed through the proximal surface of the gonioscopic device such that the beam reflects off a facet of the gonioscopic device into the anterior chamber and impinges on the identified trajectory of the anterior chamber at multiple locations around the anterior chamber, using a fixed focus setting of the beam at all multiple locations around the anterior chamber.

[0015] In a disclosed embodiment, capturing an image of the anterior chamber includes capturing an image via a gonioscope at a fixed focus setting and with a depth of field sufficient to image the entire circumference of the anterior chamber.

[0016] Additionally, according to an embodiment of the present invention, an apparatus for a medical procedure is provided. The apparatus includes a gonioscop having a distal surface configured for placement adjacent to a patient's eye, a proximal surface opposite the distal surface, and a plurality of facets extending between the distal surface and the proximal surface. The apparatus further includes a laser configured to generate a beam of optical radiation, and a scanner configured to direct the beam through the proximal surface of the gonioscop such that the beam reflects off the facets of the gonioscop into the anterior chamber of the eye. The at least one slit lamp is configured to project at least one sheet of light into the eye through the gonioscop, and the camera is configured to capture an image of an illumination pattern projected by the at least one sheet of light onto the eye through the gonioscop. The apparatus also includes a processor, the processor configured to process the image of the illumination pattern to identify a location of an anatomical structure within the eye, select one or more targets within the eye based on the identified location, and control the scanner to cause the beam to impinge on the one or more targets.

[0017] In a disclosed embodiment, the processor is configured to identify a location of the cavernous retina of the eye based on the image of the illumination pattern.

[0018] In a further embodiment, the processor is configured to select one or more targets such that the beam irradiates a cavernous retina of the eye.

[0019] In another embodiment, the at least one slit lamp is configured to project at least one sheet of light onto the cornea and iris of the eye, and the processor is configured to process an image of the illumination pattern to identify an angle of the anterior chamber of the eye.

[0020] In yet another embodiment, the processor is configured to identify the angle of the anterior chamber by finding a bend in the illumination pattern.

[0021] In a further embodiment, the apparatus includes an optical coherence tomography (OCT) unit coupled to a processor and configured to map a three-dimensional (3D) structure of the eye, the processor being configured to select one or more target points according to the 3D structure.

[0022] In another embodiment, the at least one slit lamp is configured to project multiple sheets of light into the eye through respective facets of the gonioscopic scope.

[0023] According to an embodiment of the present invention, there is further provided an apparatus for a medical procedure, comprising: a gonioscop having a distal surface configured for placement adjacent to a patient's eye and a proximal surface opposite the distal surface; an optical unit movable axially and laterally relative to an optical axis of the eye; and a fixture for coupling the gonioscop to the optical unit while aligning the optical unit to the eye via the gonioscop. The fixture comprises a mechanical stage configured to move laterally relative to the optical axis of the eye to follow the lateral movement of the optical unit; a first part attached to the optical unit; and a second part attached to the gonioscop and configured to move axially relative to the first part. The first lock is configured to lock and unlock the second part relative to the first part, and the second lock is configured to lock and unlock the second part relative to the mechanical stage.

[0024] In the disclosed embodiment, the first and second components include concentric cylinders of different respective diameters.

[0025] In a further embodiment, the first lock fixes the insertion depth of one of the concentric cylinders into the other of the concentric cylinders.

[0026] In another embodiment, the second lock fixes the axial position of the second part of the fixation device relative to the patient's eye.

[0027] In yet another embodiment, the first and second locks include respective pins that are inserted into and retracted from the respective holes.

[0028] In a disclosed embodiment, alignment of the optical unit with the eye includes an axial alignment step with the first lock closed and the second lock open, followed by a lateral alignment step with the first lock open and the second lock closed.

[0029] In a further embodiment, the optical unit includes a camera configured to capture an image of the eye through the proximal face of the gonioscope.

[0030] In another embodiment, the optical unit includes a laser configured to illuminate the eye with a beam of radiation directed through a gonioscope.

[0031] In yet another embodiment, the optical unit includes a scanner configured to direct a beam through a proximal surface of the gonioscope such that the beam reflects off a facet of the gonioscope into the anterior chamber of the eye and impinges on tissue within the anterior chamber.

[0032] In a further embodiment, the device includes a chin rest to which a mechanical stage is attached to enable lateral shifting of the fixation relative to the eye in conjunction with the optical unit while the patient's chin is resting on the chin rest.

[0033] Further, in accordance with an embodiment of the present invention, there is provided a method for a medical procedure, comprising: positioning a distal face of a gonioscopic device proximate to a patient's eye, projecting at least one sheet of light into the eye via the gonioscopic device, and capturing, via the gonioscopic device, an image of an illumination pattern projected by the at least one sheet of light onto the eye. The method further comprises processing the image of the illumination pattern to identify a location of an anatomical structure within the eye, selecting one or more targets within the eye based on the identified location, and directing a beam of optical radiation emitted by a laser through a proximal face of the gonioscopic device such that the beam strikes the one or more targets.

[0034] According to an embodiment of the present invention, there is further provided a method for a medical procedure. The method includes positioning a distal surface of a gonioscope proximate to a patient's eye and coupling the gonioscope to an optical unit that is movable axially and laterally relative to an optical axis of the eye using a fixture. The fixture includes a mechanical stage configured to move laterally relative to the optical axis of the eye to follow the lateral movement of the optical unit. The fixture further includes a first part attached to the optical unit, a second part attached to the gonioscope and configured to move axially relative to the first part, a first lock configured to lock and unlock the second part relative to the first part, and a second lock configured to lock and unlock the second part relative to the mechanical stage. The method further includes aligning the optical unit to the eye via the gonioscope using the fixture.

[0035] The present invention will be better understood from the following detailed description of the embodiments thereof, taken in conjunction with the drawings, in which: [Brief description of the drawings]

[0036] [Figure 1] FIG. 1 is a schematic side view of an SLT device, in accordance with one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of an en face image of the anterior chamber of the eye captured by a camera via a gonioscope, in accordance with an embodiment of the present invention. [Figure 3A-3C] 1A-1C are schematic diagrams of a segment of the anterior chamber angle at three successive stages of processing of a gonioscopic image, according to an embodiment of the present invention. [Figure 4A] 1A-1C are cross-sectional partial views of an eye showing the beam of the laser of an SLT device and showing the depth of field of a camera, respectively, according to one embodiment of the present invention. [Figure 4B] 1A-1C are partial frontal views of an eye showing the beam of the laser of an SLT device and showing the depth of field of a camera, respectively, according to one embodiment of the present invention. [Diagram 5]1 is a flow chart that generally illustrates a method for performing an SLT procedure, in accordance with an embodiment of the present invention. [Figure 6] FIG. 13 is a schematic side view of an SLT apparatus, in accordance with an additional embodiment of the present invention. [Figure 7] FIG. 7 is a schematic side view of a gonio-cone assembly used in the apparatus of FIG. 6, in accordance with one embodiment of the present invention. [Figure 8A-8B] 1A-1C are schematic pictorial and cross-sectional views of an eye, respectively, illustrating slit lamp illumination used to locate the spongy retina of the eye, in accordance with an embodiment of the present invention; [Figure 8C] FIG. 2 is a schematic diagram of an image captured by a camera of a portion of an eye under slit lamp illumination, according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] In an SLT procedure, the patient sits in front of the SLT machine, which is aligned with the patient's eye. The patient must maintain his or her head in a fixed position and orientation relative to the SLT machine while the laser beam is focused on and shifted across the cavernous retina by the operating ophthalmologist. As with other laser surgical procedures, the laser beam is precisely focused on each point within the cavernous retina to be treated, as indicated by the sharp focus of the aiming beam through the operating microscope. (The proper location of the treatment beam coincides with the focus of the operating microscope). Because of irregularities within the eye and the location of the gonioscopic instrument, the focus position often varies from point to point. Additionally, the microscope that the ophthalmologist uses to view the gonioscopic image must be refocused to ensure that the laser beam is properly aimed and focused. The simultaneous alignment and focusing of the surgical microscope and laser beam while firing multiple laser pulses at the cavernous retina can lengthen the procedure and tax the strength of the ophthalmologist performing the procedure, as well as the ability of the patient to maintain a constant head position and orientation.

[0038] Thus, there is a need to automate and shorten the duration of the SLT procedure while ensuring that the effectiveness of the SLT procedure is maintained. Some embodiments of the invention described herein address this problem by employing a laser that emits a loosely focused beam, for example with a small cone angle of less than 2°. This innovation is based on the recognition that the effectiveness of laser trabeculectomy does not depend on forming a precise intensity on the cavernous retina. The use of a loosely focused beam in this embodiment provides a large depth of field for the laser beam, thereby relaxing the requirements for focusing the beam and speeding up the procedure. Under such conditions, the same focus setting can generally be used around the entire circumference of the anterior chamber. This arrangement also allows the use of a camera with a large depth of field for alignment of the laser beam.

[0039] Some embodiments of the present invention provide an apparatus for a medical procedure comprising a gonioscop having a distal surface configured for placement adjacent to a patient's eye, a proximal surface opposite the distal surface, and a plurality of facets extending between the distal and proximal surfaces. A camera captures an image of the anterior chamber of the eye through the proximal surface of the gonioscop. A laser generates a beam of optical radiation, and a scanner directs the beam through the proximal surface of the gonioscop such that the beam reflects off the facets of the gonioscop into the anterior chamber and strikes tissue within the anterior chamber. In some embodiments, the optical system focuses the beam to strike tissue within the anterior chamber with a cone angle of 2° or less, and possibly less than 1.5°. Alternatively, a larger cone angle may be used. A controller processes the image of the anterior chamber to identify a trajectory of the spongy retina of the eye, and controls the scanner to direct the beam to strike the identified trajectory at a plurality of locations around the anterior chamber.

[0040] In another embodiment, a slit lamp source is integrated into the SLT device. The slit lamp projects a thin sheet of light onto the area of ​​the cornea and iris through one or more facets of the gonioscopic device. The shape of the light pattern reflected from the cornea and iris helps to identify landmarks within the eye across the cavernous retina. These landmarks then help to identify the target of the focused laser beam.

[0041] Further embodiments provide a new fixture, referred to herein as a "goniocone," to simplify alignment of the device during an SLT procedure. In a typical SLT procedure (without a goniocone), the operator's attention is required for two alignment tasks: the operator adjusts the position of the optical unit of the device with one hand (e.g., using a joystick) while simultaneously holding and aligning the gonioscope with the patient's eye with the other hand. The goniocone simplifies these tasks by holding the gonioscope in place relative to the eye, thus relieving the operator of the need to hold the gonioscope during the procedure.

[0042] In the disclosed embodiment, the goniocone comprises two parts, e.g. concentric cylinders, a first part attached to the optical unit and a second part attached to the gonioscope. In a first alignment step, the two parts of the goniocone are locked together, so that the gonioscope moves rigidly together with the optical unit. During the subsequent stages of the treatment, the second part of the goniocone is unlocked from the first part and locked to a mechanical stage that follows the movements of the optical unit only laterally relative to the optical axis of the eye. The mechanical stage is coupled to the same mechanical reference as the patient (e.g. chin rest). Thus, during these subsequent stages, the operator can freely adjust the position of the optical unit both laterally and in the direction of the optical axis of the eye (focusing) without the risk of inadvertent movement of the gonioscope in the direction of the patient's eye.

[0043] System Description FIG. 1 is a schematic side view of a partially automated SLT device 100, in accordance with one embodiment of the present invention.

[0044] The SLT device 100 comprises an optical unit 102, an XYZ stage 104, and a base unit 106. The optical unit 102 comprises a treatment laser 108 emitting a treatment beam 113 of optical radiation and an optional low intensity integrated collinear aiming beam 107, which may include its separate focusing optics (not shown). The optical unit also comprises a scanner 110, a camera 112, a camera lens 114, a fixed point 109, and a beam combiner 116 combining the optical paths of the laser 108 and the camera 112. The focusing optics 111 focuses the treatment beam 113 emitted by the laser 108 and scanned by the scanner 110 into a focused treatment beam 117 with a cone angle a of 2° or less. In an alternative embodiment, the cone angle a may be limited by the optics 111 to 1.5° or less. To focus the beam 113, an optical system 111 may be disposed in an alternative embodiment between the laser 108 and the scanner 110. The optical system 111 may also include a focusing mechanism.

[0045] In this embodiment, the laser 108 comprises a frequency doubled Nd:YAG Q-switched laser emitting pulses with a wavelength of 532 nm, a pulse duration of 1-10 nanoseconds, a pulse frequency of 1-100 Hz, and a pulse energy range of 0.2 mJ to 2.6 mJ. Alternatively, other suitable types of lasers operating in either pulsed or CW modes may be used.

[0046] The optical unit 102 further comprises a gonioscope 118 including a number of reflective facets 119 arranged in a truncated cone between a distal face 120 and a proximal face 121, and an illumination ring 122. In the examples shown in the following figures, the gonioscope has four or six facets, but alternatively the gonioscope may include any suitable number of facets or may have a continuously curved shape. The distal face 120 is concave and, in certain embodiments, is surrounded by a suction ring 123 to maintain stable contact between the patient's eye and the gonioscope. The gonioscope 118 is collinear and centered with the optical axis 127 of the camera 112.

[0047] In the illustrated embodiment, the scanner 110 comprises two galvanometer mirrors 124 and 125 that rotate over two orthogonal axes (not shown for simplicity), the rotation of which is indicated by respective circular arrows 126 and 128. The scanner 110 is configured to direct the beam 117 through the proximal surface 121 of the gonioscopic device 118 such that the beam reflects from the gonioscopic facet 119 through the distal surface 120 into the anterior chamber 129 (FIG. 4A) of the eye 142 in contact with the distal surface to impinge on tissue within the anterior chamber. Alternatively, other types of scanners may be used. For example, the scanner 110 may comprise a voice coil actuated mirror.

[0048] The XYZ stage 104 moves the optical unit 102 in three orthogonal linear X, Y and Z directions, as indicated by Cartesian coordinates 130. In this and subsequent figures, the Z direction corresponds to the optical axis 127.

[0049] The base unit 106 comprises a controller 132, and a monitor and user control unit 134. The controller 132 is coupled to the camera 112, the laser 108, the scanner 110, the XYZ stage 104, the monitor, and the user control unit 134. Alternatively, the entire monitor and / or user control unit 134 and / or the controller may be integrated into the optical unit 102.

[0050] Controller 132 typically comprises a programmable processor that is programmed with software and / or firmware to perform the functions described herein. Alternatively or additionally, controller 132 comprises hardwired circuitry and / or programmable hardware logic circuitry that performs at least some of the functions of the controller. Although controller 132 is shown in the figures as a single monolithic functional block for simplicity, in practice the controller may comprise a single chip or a set of two or more chips with appropriate interfaces for receiving and outputting the signals shown in the figures and described herein.

[0051] The monitor and user control unit 134 includes one or more visual displays and suitable input devices, such as a keyboard, joystick, and / or mouse, to enable an operator 136 to interact with the SLT apparatus 100. (Details of the monitor and user control unit 134 have been omitted from the figures for simplicity.)

[0052] For the SLT procedure, the patient positions their head 140 in front of the optical unit 102 so that their eye 142 is proximate to the distal surface 120 of the gonioscope 118. The device 100 typically includes a chin rest 144 and a forehead rest 146 to enhance stability of the patient's head 140 during the procedure. The chin rest 144 and forehead rest 146 may be integrated into the base unit 106 or may be attached to the table of the device 100. Fixation points 109 are provided for the patient to align and stabilize their eye 142.

[0053] The operator 136 observes the eye 142 in the image captured by the camera 112 and displayed on the monitor of the unit 134. For this purpose, the eye 142 may be illuminated, for example, by the illumination ring 122, or alternatively, other types of light sources may be used. The camera 112, together with the lens 114, has a sufficient depth of field to capture the entire circumference of the anterior chamber 129 of the eye 142 with a single focus setting of the camera. While observing the eye, the operator 136 moves the optical unit 102 in the X and Y directions using an input device such as a joystick, such that the optical axis 127 of the camera 112 is aligned with the eye 142. The operator 136 then moves the optical unit 102 in the Z direction to bring the concave surface of the distal surface 120 into contact with the cornea of ​​the eye 142 (FIG. 4A). Before contact, a gel or other suitable contact material may be applied to the cornea 149. In certain embodiments, the suction ring 123 maintains stable contact between the eye 142 and the gonioscope 118 .

[0054] After the above-described alignment process, the operator 136 fine-tunes the XY position of the optical unit 102 to center the eye 142 within the field of view of the camera 112 (e.g., as shown in FIG. 2) and image the entire 360° field of view. The same fixed focus setting is used around the entire circumference of the anterior chamber 129, and there is no need to refocus the camera 112 at different points around the circumference, even if the image is not perfectly sharp at all points. As described in more detail below with reference to FIGS. 3A-3C, the controller 132 identifies the trajectory of the cavernous retina of the eye 142 in the image captured by the camera 112, and then instructs the scanner 110 to direct the beam 117 to impinge on the cavernous retina at multiple locations around the anterior chamber during the procedure. Before actually firing the laser 108, the operator 136 verifies the location of the trajectory 308 on the cavernous retina, and the alignment of the laser, using the aiming beam 107 displayed on the monitor. Once the laser 108 is activated to emit the beam 113, a typical procedure may take less than a minute, and in some cases only a few seconds, using a pulse frequency of 50-100 Hz and a pulse energy of about 1 mJ. Prior to emitting the treatment beam 113, the aiming beam 107 may be swept over the target point, with operation verified by the operator 136 before proceeding to treatment mode.

[0055] FIG. 2 is a schematic diagram of an en face image 200 of the anterior chamber of eye 142 captured by camera 112 via gonioscope 118, according to one embodiment of the present invention.

[0056] Image 200 includes both a direct image 202 of the anterior chamber and a reflected image 204 reflected by facets 119 of gonioscope 118. In the embodiment shown in Figure 2, gonioscope 118 includes six reflective facets 119, although in alternative embodiments the number of facets 119 may be less than or greater than six, such as four, eight, twelve, or any other number of facets.

[0057] The direct image 202 includes an image of the iris 206 and pupil 208 of the eye 142 without reflection from the facets 119. Each reflected image 204 may include a partial iris image 212 and may include a partial pupil image 210. Additionally, each reflected image 204 includes an image segment 214 of the angle of the anterior chamber, which corresponds to the locus of a respective portion of the spongiform retina (as shown in FIG. 4A). Due to the large depth of field of the camera 112, the image segments 214 reflected by each facet 119 can be sufficiently focused simultaneously on the camera in all reflected images 204 to aim the weakly focused treatment beam 117, avoiding the need to refocus the camera on different portions of the anterior chamber angle, thus speeding up the treatment. However, due to the optical structure of the gonioscopic scope 118, the image segments 214 are distorted and separated from each other, as will be explained in more detail below with reference to FIG. 3A.

[0058] 3A-3C show schematic diagrams of image segments 302 of the anterior chamber angle 216 around 360° at three respective stages of processing of an image captured by the camera 112, according to one embodiment of the present invention.

[0059] 3A shows image segments 302 of the anterior chamber angle 216 captured through a gonioscopic device (similar to gonioscopic device 118, but with four reflective facets). The eye's spongy retina 150 lies within the angle 216. As shown in FIG. 2 above, the image segments 302 captured by the camera 112 are distorted from their actual shape and are separated from one another.

[0060] FIG. 3B is a schematic image 304 of a (generally) elliptical successive images of the anterior chamber angle 216 and the spongy retina 150, with the controller 132 having undistorted stitched image segments 302 to identify the locus of the spongy retina.

[0061] 3C is a schematic image 306 in which controller 132 has identified a locus 308 (dotted line) of the spongy retina 150 along the periphery of the anterior chamber. Controller 132 controls laser 108 and scanner 110 to fire and direct laser beam 117 to impinge on the spongy retina at multiple locations around locus 308.

[0062] 4A and 4B show schematic cross-sectional and frontal partial views 404 and 414 of eye 142, showing beam 117 of laser 108 and showing depth of field 402 of camera 112, according to one embodiment of the present invention.

[0063] The cross-sectional view 404 of FIG. 4A includes an anterior segment 406 of the eye 142. The anterior segment 406 is comprised of the iris 206, pupil 208, cornea 149, anterior chamber 129 (filled with aqueous humor), lens 412, and spongy retina 150 of the eye 142. (Additional structures in the anterior segment 406 in the figure are not relevant to the current discussion and are left unlabeled for simplicity.) The angle 216 of the anterior chamber angle 149 is located between the cornea 149 and the iris 206 and includes the spongy retina 150. The cross-sectional view 404 further includes a partial cross-sectional view of the gonioscopic scope 118, showing two facets 119 and a portion of the distal surface 120.

[0064] The beam 117 of the laser 108 reflects off one of the facets 119 of the gonioscopic scope 118, through the cornea 149 and the anterior chamber 129 (refraction is ignored for clarity) and impinges on the spongy retina 150. Due to the low value of the cone angle a (less than 3°), the beam 117 has a sufficient spot size to deliver laser energy to the spongy retina 150 over a sufficient depth to the entire retina over a 360° circumference without the need to refocus the laser 108 during the procedure.

[0065] The camera 112 is focused on the anterior chamber angle 216 and the cavernous retina 150 with a depth of field 402 sufficient to capture the entire image 200 (FIG. 2) with a single focus setting of the camera. For example, the depth of field may be greater than 1 mm, or greater than 2 mm, or greater than 3 mm, or greater than 4 mm, or even greater than 5 mm. The depth of field 402 is tied to the size of the blur circle of the camera 112, which means that the depth of field in this case refers to the ability of the controller 132 to aim the focused treatment beam 117 in the direction of the cavernous retina 150 even if the cavernous retina is not in sharp focus when viewed by the operator 136.

[0066] The front view 414 of FIG. 4B shows the cavernous retina 150 and the anterior chamber angle 216 shown in the XY plane of Cartesian coordinates 130 indicated in the figure by the X and Y axes 420. For this two-dimensional representation, the laser beam 117 and the depth of field 402 of the camera 112 are shown flattened in their Z direction and reshaped into a circle in the XY plane. A small cone angle a of the beam 117 defines a treatment region 416 extending through the cavernous retina 150 with a typical laser spot size S of 0.4 mm. As an example, a cone angle of 1.5° results in a depth D of 3 mm for the region 416, with the spot size varying by ±10% over the region. The depth of field 402 of the camera 112 may be 2 mm, 3 mm, 4 mm, or larger. Making the camera depth of field 402 equal to or greater than the laser depth of focus D ensures that for a focused image of the camera 112, the beam 117 is also focused.

[0067] FIG. 5 is a flow chart 500 that generally illustrates a method for performing an SLT procedure using the SLT device 100, in accordance with one embodiment of the present invention.

[0068] The procedure begins at a start step 502. In a head positioning step 504, the patient positions his / her head 140 adjacent to the gonioscope 118 (FIG. 1). In an alignment step 506, the operator 136 aligns the optical unit 102 with the eye 142 in the XY plane. In a Z movement step 508, the operator 136 moves the optical unit 102 in the Z direction so that the cornea 149 of the eye 142 contacts the distal surface 120 of the gonioscope 118. In a centering and focusing step 510, the operator 136 centers and focuses the optical unit 102 to position the eye 142 at or near the center of the field of view of the camera 112. In an image capture step 512, the operator 136 captures an image of the eye 142 via the gonioscope 118 using the camera 112.

[0069] In image processing step 514, the controller 132 processes the captured image to define the trajectory 308 of the cavernous retina 150 (FIG. 3C). In target verification step 516, the operator 136 visually checks the trajectory 308 on the cavernous retina 150. Optionally, the aiming beam 107 is fired over some or all of the trajectory of the target points and displayed on the monitor 134 to verify correct laser operation. If the trajectory matches the cavernous retina, the operator fires the laser 108 to strike multiple points over the trajectory in firing step 518. (If the trajectory identified by the controller does not match the cavernous retina 150, the operator 136 can instruct the SLT device 100 to return to centering and focusing step 510 or manually adjust the trajectory). The SLT procedure ends in end step 520.

[0070] Figure 6 is a schematic side view of a partially automated SLT device 600 according to an additional embodiment of the present invention. The device 600 is similar to the device 100 (Figure 1), and in Figure 6 the labels of Figure 1 are used for the same or similar items. The device 600 includes the following items not present in the device 100: a goniocone assembly 602, optionally one or more slit lamps 604, and / or an optical coherence tomography (OCT) unit 606 having a beam combiner 608. The goniocone assembly 602, slit lamps 604, and OCT unit 606 are shown together in Figure 6 for convenience, although in practice each of these elements may be incorporated and used separately and independently of the other elements.

[0071] The goniocone assembly 602 is a fixture that connects between the gonioscope 118 and the optical unit 102, as described in more detail in FIG. 7 below. One of the slit lamps 604 projects a thin sheet of light (not shown) that is reflected by one or more facets 119 of the gonioscope 118 onto the eye 142 at an off-axis angle, such as 45°, 30°, 20°, 10°, or 5°. As described in more detail in FIG. 8 below, the reflection of the sheet of light from the eye 142 provides an indication of the eye's topography and helps align the treatment beam 117 with the cavernous retina 150. Instead of one sheet of light, multiple sheets of light may be projected by one slit lamp 604 through multiple facets 119 of the gonioscope 118, or multiple sheets of light may be projected from multiple slit lamps. These can be utilized to speed up the establishment of the topography of the eye 142 and the alignment of the treatment beam 117 .

[0072] The OCT unit 606 emits a coherent beam 610 that is optically aligned with the aiming beam 107 by a beam combiner 608. By utilizing the return of the beam 610 from the eye 142, the OCT unit 606 maps the 3D structure of the eye and transmits it to the controller 132. The measured 3D structure provides additional assistance in aligning the focused treatment beam 117 to the cavernous retina 150.

[0073] Data from both the slit lamp 604 and the OCT unit 606 can be displayed to the operator 136 for optimal alignment of the optical unit 102 over a full 360° of azimuth.

[0074] The embodiment depicted in FIG. 6 may be utilized in both applications where the cone angle a of the focused treatment beam 117 is less than 3° and greater than 3°, as discussed above.

[0075] 7 is a schematic side view of a gonio-cone assembly 602, according to one embodiment of the present invention. Labels from FIG. 6 are used in FIG. 7 for the same or similar items.

[0076] The goniocone assembly 602 comprises an outer cylinder 620, an inner cylinder 622, a goniocone support 624, an XY follower 626, an outer lock 628, and an inner lock 630. The goniocone assembly 602 interfaces with the optical unit 102, the controller 132, the gonioscope 118, and with the head 140 via the chin rest 144 and via a connecting ring 632. The outer cylinder 620 and the inner cylinder 622 are hollow, concentric cylinders, with the inner cylinder free to move in the Z direction within the outer cylinder. The outer cylinder 620 is attached to the proximal face 121 of the optical unit 102, and the inner cylinder 622 is attached to the gonioscope 118. The outer lock 628 locks the inner cylinder 622 to the outer cylinder 620, and the inner lock 630 locks the inner cylinder to the XY follower 626 via the support 624. The locks 628 and 630 may comprise any suitable type of locking mechanism, such as pins inserted into and withdrawn from corresponding holes, or friction locks. The locking mechanisms of the locks 628 and 630 may be actuated, for example, by electric motors or by pneumatic or hydraulic cylinders. The XY follower 626 attached to the chin rest 144 comprises a stage movable in both the X and Y directions. The XY follower 626 may comprise either an electromechanical stage coupled to the controller 132, or alternatively a mechanical stage. The functionality of the two alternative stages is described in more detail below. The locks 628 and 630 are coupled to the controller 132, which sends commands to lock and unlock the locks. Optionally, the inner cylinder 622 may include a spring or similar element that provides a gentle force in the axial (Z) direction to ensure constant contact between the distal face 120 of the gonioscope 118 and the cornea 149.

[0077] The goniocone assembly 602 allows the operator 136 to perform an initial XYZ alignment between the optical unit 102 and the eye 142, and then adjust the alignment of the optical unit during the procedure without inadvertently moving the gonioscope 118 into the eye. An SLT procedure using the goniocone assembly 602 begins by following steps 502-508 of the flowchart 500 (FIG. 5) during which the inner cylinder 622 is locked to the outer cylinder 620 by the outer lock 628, thereby fixing the insertion depth of the inner cylinder 622 within the outer cylinder 620. (The inner lock 630 is released at this stage.) With the inner cylinder 622 locked to the outer cylinder 620 up to and including step 508, the gonioscope 118 follows the XYZ alignment of the optical unit 102. At the end of step 508, the distal surface 120 of the gonioscope 118 is in contact with the cornea 149 of the eye 142. After completion of step 508, the inner cylinder 622 inside the connecting ring 632 is locked to the XY follower 626 by the inner lock 630, thereby fixing the axial position (Z position) of the goniocone assembly 602 relative to the chin rest 144, and the outer lock 628 is released. With this arrangement, the axial position of the gonioscope 118 is referenced to the eye 142 via the chin rest 144 and head 140, and movement of the optical unit 102 in the axial (Z direction) is not transferred to the gonioscope, thus preventing axial (Z direction) movement of the optical unit from pushing the gonioscope into the eye.

[0078] If the XY follower 626 comprises an electromechanical device, it shifts the support 624 and the inner cylinder 622 according to the XY adjustment of the XYZ stage 104 (FIG. 6) performed by the operator 136 in step 510, based on the command from the controller 132, to keep the eye 142 centered with respect to the gonioscope 118. If the XY follower 626 is purely mechanical, the support 624 is free to move in the X and Y directions, but not in the Z direction. Thus, the XY movement of the optical unit 102 is transferred to the inner cylinder 622 by the outer cylinder 620 pushing in the X and Y directions. (In principle, this function can be obtained even without the XY follower 626, but the locking of the inner cylinder 622 and the gonioscope 118 to the chin rest 144 is not guaranteed). Because the outer lock 628 is released, there is no risk that Z movement of the optical unit 102 will be transmitted to the gonioscope 118, and the operator 136 is free to adjust the position of the optical unit using the joystick or other control of the unit 134. The remaining steps 510-520 of the procedure can then be continued without the operator holding or manually manipulating the gonioscope.

[0079] In an alternative embodiment, the goniocone assembly 602 may comprise first and second mechanical parts with appropriate mechanical coupling for Z-direction adjustment and locking, instead of concentric cylinders as described above. For example, the first and second parts may each comprise a rail or rod. The first part is attached to the optical unit 102 and the second part is attached to the gonioscope 118. The two parts are movable and lockable by first and second locks, similar to the outer cylinder 620 and inner cylinder 622 described above.

[0080] Figures 8A and 8B are two schematic diagrams of slit lamp illumination on eye 142 for locating the cavernous retina 150, according to one embodiment of the present invention. Labels from Figures 4A and 6 are used in Figures 8A and 8B for the same or similar items.

[0081] FIG. 8A is a schematic pictorial diagram of the eye 142 as seen through the cornea 149. The direction of gaze, indicated by the arrow 802 in both FIG. 8A and FIG. 8B, is in the YZ plane of Cartesian coordinates 130. (To clarify the direction of view, the entire eye 142 is shown in FIG. 8A, including the complete sclera 814. In reality, the view through the gonioscope 118 includes the iris 206, the pupil 208, the cornea 149, and only a small portion of the sclera 814 that spans the iris and cornea.) The eye 142 is illuminated with a thin sheet of light 804 from one of the slit lamps 604. The sheet of light 804 reflects from the cornea 149 and the iris 206 as two respective elongated patterns 806 and 808. The patterns 806 and 808 meet at an elbow-like bend 810.

[0082] FIG. 8B is a cross-sectional view of eye 142 showing patterns 806 and 808 reflected from a sheet of light 804 from a slit lamp. Bend 810 is located at angle 812 in anterior chamber 816 of eye 142. Angle 812 is the point where the curvature of cornea 149 meets iris 206 of eye 142. Angle 812 is a landmark located within a known offset from spongy retina 150. Alternatively, by observing pattern 806 as sheet of light 804 moves along cornea 149, the corneal boundary 820 (FIG. 8C) can be found at the minimum width of pattern 806. The center of spongy retina 150 is located between boundary 820 and angle 812.

[0083] 8C is an exemplary image of patterns 806 and 808 captured by camera 112 of device 600, according to one embodiment of the present invention. A portion 816 of cornea 149 is shown in dashed line. Controller 132 processes the image to find the location of bend 810, which indicates the location of angle 812. Controller 132 then finds the location of spongy retina 150, indicated by arrow 818, at a known offset from angle 812. Alternatively or additionally, controller 132 processes the image to find boundary 820 of cornea 149, and then finds the location of spongy retina 150 between the corneal boundary and angle 812.

[0084] Illumination from the slit lamp 604 and / or 3D mapping by the OCT unit 606 of the structures of the eye 142 may be used in a centering and focusing step 510 (FIG. 5). The controller 132 utilizes the symmetry of the slit lamp illumination as well as the determination of the angle 812 for lateral (XY) alignment while using the image of the eye 149 captured by the camera 112 to focus the camera on the eye.

[0085] The controller 132 can determine, at step 514, a locus 308 (FIG. 3C) of a target point on the cavernous retina 150 by using landmarks indicated by the 3D OCT map of the eye 149 and / or slit lamp illumination, as shown in FIGS. 8A-8C above. Other landmarks of the eye 142 known in ophthalmology, such as the ciliary zone, Schwalbe's lines, scleral spines, or edges of the iris 206, with known offsets from the cavernous retina 150, may additionally be utilized in determining the target point.

[0086] Once the trajectory 308 is verified in step 516, the controller 132 can, in step 518, track the eye while firing the laser 108 based on pattern recognition of landmarks or images of the pupil 208 and / or iris 206 captured by the camera 112.

[0087] The above-described embodiments have been cited by way of example, and it will be understood that the present invention is not limited to what has been particularly shown and described above. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described above, as well as variations and modifications thereof not disclosed in the prior art that would occur to those skilled in the art upon reading the foregoing description. [Explanation of symbols]

[0088] 100 SLT equipment 102 Optical unit 104 XYZ Stage 106 Base Unit 107 Aiming Beam 108 Laser 109 fixed points 110 Scanner 111 Optical system 112 Camera 113, 117 Therapeutic beams 114 Lens 116 Beam Combiner 118 Gonioscope 119 Facet 120 Distal surface 121 Proximal surface 122 Lighting Ring 123 Suction Ring 124, 125 Galvano mirror 127 Optical axis 129 Anterior chamber 130 Cartesian Coordinates 132 Controller 134 Monitor and User Control Unit 136 Operator 142 Eyes 149 Cornea 150 Cavernous Retina 200 Frontal Images 202 Direct Image 204 Reflection Images 206 Iris 208 Pupil 210 Pupil Images 212 Iris Images 214, 302 Image segments 216 Anterior chamber angle 304, 306 Outline images 308 Trajectory 402 Depth of field 404 Sectional view 412 Crystalline lens 414 Front view 416 Treatment Area

Claims

1. 1. An apparatus for a medical procedure, comprising: a gonioscopic device having a distal surface configured for placement adjacent to a patient's eye, a proximal surface opposite the distal surface, and a number of facets extending between the distal and proximal surfaces; a laser configured to generate a beam of optical radiation; a scanner configured to direct the beam through the proximal surface of the gonioscopic device such that the beam reflects off a facet of the gonioscopic device into the anterior chamber of the eye; at least one slit lamp configured to project at least one sheet of light into the eye via the gonioscopic scope; a camera configured to capture an image of an illumination pattern projected by the at least one light sheet onto the eye via the gonioscope; and a processor configured to process the images of the illumination pattern to identify locations of anatomical structures within the eye, select one or more targets within the eye based on the identified locations, and control the scanner to cause the beam to impinge on the one or more targets; An apparatus comprising:

2. The apparatus of claim 1 , wherein the processor is configured to identify a location of a cavernous retina of the eye based on the image of the illumination pattern.

3. 3. The apparatus of claim 2, wherein the processor is configured to select the one or more targets such that the beam irradiates the cavernous retina of the eye.

4. 2. The apparatus of claim 1, wherein the at least one slit lamp is configured to project the at least one sheet of light onto a cornea and an iris of the eye, and the processor is configured to process the image of the illumination pattern to identify an angle of an anterior chamber of the eye.

5. The apparatus of claim 4 , wherein the processor is configured to identify the angle of the anterior chamber by finding a bend in the illumination pattern.

6. 2. The apparatus of claim 1, comprising an optical coherence tomography (OCT) unit coupled to the processor and configured to map a three-dimensional (3D) structure of the eye, the processor configured to select the one or more target points according to the 3D structure.

7. 10. The apparatus of claim 1, wherein the at least one slit lamp is configured to project a plurality of sheets of light into the eye through respective facets of the gonioscopic device.

8. 1. An apparatus for a medical procedure, comprising: a gonioscopic device having a distal surface configured for placement adjacent to a patient's eye and a proximal surface opposite the distal surface; an optical unit movable axially and laterally relative to the optical axis of the eye; a fixture for coupling the gonioscope to the optical unit while aligning the optical unit with the eye via the gonioscope, a mechanical stage configured to move laterally relative to the optical axis of the eye to follow lateral movements of the optical unit; A first component attached to the optical unit; a second part attached to the gonioscope and configured to move axially relative to the first part; a first lock configured to lock and unlock the second part to the first part; a second lock configured to lock and unlock the second part relative to the mechanical stage; and A fixture including: An apparatus comprising:

9. The apparatus of claim 8 , wherein the first and second parts comprise concentric cylinders of different respective diameters.

10. 10. The apparatus of claim 9, wherein the first lock fixes the insertion depth of one of the concentric cylinders into the other of the concentric cylinders.

11. 10. The apparatus of claim 8, wherein the second lock fixes an axial position of the second part of the fixator relative to the eye of the patient.

12. 9. The apparatus of claim 8, wherein the first and second locks comprise respective pins that are inserted into and withdrawn from respective holes.

13. 9. The apparatus of claim 8, wherein alignment of the optical unit with the eye comprises an axial alignment step with the first lock closed and the second lock open, followed by a lateral alignment step with the first lock open and the second lock closed.

14. The apparatus of claim 8 , wherein the optical unit comprises a camera configured to capture an image of the eye through the proximal face of the gonioscope.

15. 9. The apparatus of claim 8, wherein the optical unit comprises a laser configured to illuminate the eye with a beam of radiation directed through the gonioscope.

16. 16. The apparatus of claim 15, wherein the optical unit comprises a scanner configured to direct the beam through the proximal surface of the gonioscope such that the beam reflects off a facet of the gonioscope into the anterior chamber of the eye and strikes tissue within the anterior chamber.

17. 9. The apparatus of claim 8, further comprising a chin rest to which the mechanical stage is attached to laterally shift the fixation device relative to the eye while the patient's chin rests on the chin rest.

18. 1. A method for a medical procedure, comprising: placing a distal surface of the gonioscopic device adjacent to an eye of the patient; projecting at least one sheet of light into the eye via the gonioscopic device; capturing an image of an illumination pattern projected by the at least one light sheet onto the eye via the gonioscope; processing the image of the illumination pattern to identify a location of an intraocular anatomical structure; and selecting one or more targets within the eye based on the identified location; and directing a beam of optical radiation emitted by a laser through a proximal face of the gonioscope such that the beam impacts the one or more targets; A method comprising:

19. 20. The method of claim 18, wherein identifying the location comprises locating the location of a cavernous retina of the eye based on the illumination pattern.

20. 20. The method of claim 19, wherein selecting the one or more targets comprises selecting the one or more targets such that the beam irradiates the cavernous retina of the eye.

21. 20. The method of claim 18, wherein projecting the at least one sheet of light includes illuminating a cornea and an iris of the eye with the at least one sheet of light, and processing the image includes determining an angle of an anterior chamber of the eye.

22. 22. The method of claim 21, wherein identifying the angle of the anterior chamber comprises finding a bend in the illumination pattern.

23. 20. The method of claim 18, comprising mapping a three-dimensional (3D) structure of the eye using optical coherence tomography (OCT), and selecting the one or more target points comprises identifying the one or more target points according to the 3D structure.

24. 20. The method of claim 18, wherein projecting at least one sheet of light comprises projecting a plurality of sheets of light into the eye through respective facets of the gonioscopic device.

25. 1. A method for a medical procedure, comprising: placing a distal surface of the gonioscopic device adjacent to an eye of the patient; coupling the gonioscopic device to an optical unit movable axially and laterally relative to an optical axis of the eye using a fixture, the fixture comprising: a mechanical stage configured to move laterally relative to the optical axis of the eye to follow lateral movements of the optical unit; A first component attached to the optical unit; a second part attached to the gonioscope and configured to move axially relative to the first part; a first lock configured to lock and unlock the second part to the first part; a second lock configured to lock and unlock the second part relative to the mechanical stage; and and aligning the optical unit to the eye via the gonioscope using the fixture; A method comprising:

26. 26. The method of claim 25, wherein the first and second parts comprise two concentric cylinders of different respective diameters.

27. 27. The method of claim 26, wherein aligning the optical unit comprises closing the first lock to fix an insertion depth of one of the concentric cylinders into the other of the concentric cylinders.

28. 26. The method of claim 25, wherein aligning the optical unit includes closing the second lock to fix an axial position of the second part of the fixation device relative to the eye of the patient.

29. 26. The method of claim 25, wherein aligning the optical unit comprises an axial alignment step with the first lock closed and the second lock open, followed by a lateral alignment step with the first lock open and the second lock closed.

30. 26. The method of claim 25, wherein the first and second locks comprise respective pins that are inserted into and withdrawn from respective holes.

31. 26. The method of claim 25, comprising using the optical unit to capture an image of the anterior chamber of the eye through the proximal face of the gonioscope.

32. 26. The method of claim 25, comprising illuminating the eye with a beam of laser radiation directed from the optical unit through the gonioscope.

33. 33. The method of claim 32, wherein illuminating the eye comprises directing the beam through the proximal face of the gonioscope such that the beam reflects off a facet of the gonioscope into the anterior chamber of the eye and strikes tissue within the anterior chamber.

34. 26. The method of claim 25, wherein coupling the gonioscopic device includes mounting the mechanical stage to a chin rest, and aligning the optical unit includes shifting the fixture laterally relative to the eye by movement of the mechanical stage while the patient's chin rests on the chin rest.

Images