System for aligning an eye with a patient interface of an ophthalmic laser device

Abstract

In certain embodiments, a system for aligning an eye with a patient interface of a laser device includes a camera, a display screen, and a computer. The camera records an image of the eye through the patient interface of the laser device. A liquid is placed between the patient interface and an external surface of the eye and contacts the patient interface and the external surface of the eye. The image includes an outline of the liquid. The display screen displays the image of the eye. The computer aligns the eye with the patient interface by identifying the outline of the liquid in the image received from the camera, determining a misalignment of the eye according to the outline, and instructing the display screen to display a description of the misalignment.

Description

Technical Field

[0001] The present disclosure generally relates to ophthalmic laser devices, and more particularly to aligning the eye with a patient interface of an ophthalmic laser device.

Background Art

[0002] Certain ophthalmic laser surgical systems have a laser device that generates a pulsed laser beam for performing a surgical procedure on an eye. In some procedures, the laser beam causes photoablation at specific points on the eye according to a treatment pattern. To cause photoablation that exactly matches the pattern, the laser beam should be properly aligned with the eye. To align the laser beam with the eye during the procedure, a patient interface (PI) coupled to the laser device is typically used. The patient interface is typically attached to the eye by suction to hold the eye in a predetermined position and properly position the eye relative to the treatment pattern.

[0003] Aligning the eye and the patient interface and coupling the interface to an appropriate position over the eye, i.e., "docking" the interface over the eye, is not easy. According to one known docking process, the patient is required to fixate on a fixation light coaxial with the laser beam, and then the surgeon manually positions the interface over the eye. However, patients often have difficulty fixating on the fixation light, especially once the interface comes into contact with the eye, resulting in a decrease in alignment accuracy. According to another known docking process, the pupil of the eye can be imaged and used to align the patient interface with the eye. However, some types of patient interfaces may distort the pupil when the interface is placed over the eye, resulting in a decrease in alignment accuracy. These known processes can result in an incomplete placement of the interface over the eye, such as the laser beam not being centered on the eye and / or being angled with respect to the axis of the eye. In certain procedures, misalignment can lead to suboptimal results. For example, in lamellar keratoplasty, the corneal lamella created using a misaligned laser beam may not be centered on the eye and / or may be angled with respect to the axis of the eye, leading to suboptimal vision correction. Summary of the Invention Means for Solving the Problems

[0004] In certain embodiments, a system for aligning an eye with a patient interface of a laser device includes a camera, a display screen, and a computer. The camera records an image of the eye through the patient interface of the laser device. A liquid is disposed between the patient interface and the outer surface of the eye. The liquid contacts the patient interface and the outer surface of the eye. The image includes the contour of the liquid. The display screen displays the image of the eye. The computer aligns the eye with the patient interface to align the eye with the laser beam of the laser device. The eye is aligned to treat the eye according to a treatment pattern. The computer identifies the contour of the liquid in the image received from the camera, determines the misalignment of the eye according to the contour, and aligns the eye with the patient interface by instructing the display screen to display an explanation of the misalignment.

[0005] Embodiments may include none, one, several, or all of the following features.

[0006] The computer determines the misalignment of the eye according to the contour by identifying that the shape of the contour is elliptical and determining that the axis of the eye is angled with respect to the z-axis of the laser device.

[0007] The computer determines the misalignment of the eye according to the contour by determining that the centroid of the shape of the contour is not at the center point of the laser device and determining that the eye is laterally displaced with respect to the center point of the laser device.

[0008] The computer determines an adjustment that substantially compensates for the misalignment. For example, the computer identifies that the shape of the contour is elliptical, determines in response to the shape identification that the axis of the eye is angled with respect to the z-axis of the laser device, and determines that the misalignment is substantially compensated when the eye is rotated, thereby determining an adjustment that substantially compensates for the misalignment. For example, the computer determines that the centroid of the shape of the contour is not at the center point of the laser device, determines that the eye is laterally displaced by a certain distance with respect to the center point of the laser device, and determines that the misalignment is substantially compensated when the eye is translated towards the center point by the determined distance, thereby determining an adjustment that substantially compensates for the misalignment. In certain embodiments, the computer instructs the display screen to display an explanation of the adjustment. In certain embodiments, the computer adjusts the patient interface or the eye according to the adjustment for compensating the misalignment. In certain embodiments, the computer adjusts the treatment pattern according to the adjustment for compensating the misalignment.

[0009] The computer generates an alignment overlay indicating the desired position and desired shape of the contour for aligning the eye and the patient interface, places the alignment overlay on the image, and instructs the display screen to display the image together with the alignment overlay. In certain embodiments, the computer receives a depiction of the corneal topography of the eye and determines the desired position and desired shape of the contour for aligning the eye and the patient interface according to the corneal topography of the eye. In certain embodiments, the computer determines a plurality of alignment overlays where each alignment overlay corresponds to a specific distance between the eye and the patient interface, determines the distance between the eye and the patient interface, and generates the alignment overlay corresponding to the determined distance.

[0010] The computer determines the distance between the eye and the patient interface according to the size of the contour. In certain embodiments, the computer instructs the display screen to display the distance between the eye and the patient interface. In certain embodiments, the computer adjusts the distance of the eye from the patient interface according to the determined distance between the eye and the patient interface.

[0011] The computer performs a liquid dispensing procedure for redistributing the liquid by moving the patient interface away from the eye and moving the patient interface closer to the eye.

[0012] The system further includes a dispenser configured to dispense additional liquid onto the outer surface of the eye. The computer instructs the dispenser to dispense additional liquid onto the outer surface of the eye. In certain embodiments, the additional liquid includes a substance capable of changing the surface tension of the liquid. In certain embodiments, the additional liquid includes a substance for enhancing the visibility of the liquid.

[0013] The system further includes a suction device configured to remove at least a portion of the liquid from the outer surface of the eye. The computer instructs the suction device to remove at least a portion of the liquid from the outer surface of the eye.

Brief Description of the Drawings

[0014]

Figure 1

Figures 2A - 2B

Figure 3

Figures 4A - 4B

Figures 5A - 5B

Figures 6A - 6B

Figures 7A - 7B

Figure 8

Figures 9A - 9C

Figures 10A - 10B

Figures 11A - 11B

Figures 12A - 12C

Figure 13

Figure 14

DETAILED DESCRIPTION OF THE INVENTION

[0015] Here, with reference to the description and the drawings, exemplary embodiments of the disclosed apparatus, system, and method are shown in detail. The description and the drawings are not intended to be exhaustive or to limit the claims to the specific embodiments shown in the drawings and disclosed in the description. The drawings represent possible embodiments, but the drawings are not necessarily to scale and may simplify, exaggerate, delete, or partially divide certain features to better illustrate the embodiments.

[0016] In certain ophthalmic surgical procedures, the patient interface (PI) is used to couple the eye to the surgical system in order to properly align the eye with the treatment pattern. There can be an issue that it may be difficult to align the eye and the patient interface to attach the interface to the eye. Certain embodiments can address this issue.

[0017] FIG. 1 shows an example of an ophthalmic surgical system 10 configured to align an eye 22 and a patient interface 20 according to a particular embodiment. In the embodiment, the system 10 images a liquid (not shown) disposed between the patient interface 20 and the eye 22. The contour of the liquid indicates the alignment of the eye 22 with respect to the patient interface 20. The system 10 uses the contour of the liquid to align the eye 22 and the interface 20 during the docking process. Thus, the system 10 can address the issue of attaching the patient interface 20 to the eye 22 such that the eye is aligned with the treatment pattern.

[0018] Generally, aligning the eye 22 with the patient interface 20 means positioning the eye 22 relative to the patient interface 20 (or the patient interface 20 relative to the eye 22) such that when the interface 20 is attached to the eye 22, the laser beam passing through the interface 20 hits the appropriate point on the eye 22 and at the appropriate angle according to the treatment pattern. Note that "aligning the eye 22 with the patient interface 20" also includes aligning the patient interface 20 with the eye 22. In certain embodiments, the alignment may be described according to the xyz coordinate system of the laser device of the system 10 where the central laser beam defines the z-axis and the abutment surface of the patient interface 20 defines the xy plane at z = 0. In an embodiment, the center point (x, y, z) = (0, 0, 0) and the central axis z = 0 (or z-axis) of the patient interface 20 (and thus of the laser device 15) are aligned with the respective center point (e.g., pupil center, apex of the eye or vertex of the eye) and central axis (e.g., optical axis or visual axis) of the eye 22. However, any suitable feature of the patient interface 20 may be aligned with any suitable feature of the eye so that the laser beam hits the appropriate part of the eye 22 according to the treatment pattern.

[0019] Misalignment can occur in several different ways. (1) The eye 22 can be laterally misaligned by a lateral shift in the x-direction and / or y-direction. (2) The eye 22 can have a rotational misalignment where the axis of the eye 22 and the axis of the interface 20 are not aligned, i.e., these axes form an angle greater than zero degrees (e.g., greater than 3 degrees) relative to each other. (3) The eye 22 can be twisted and misaligned by a rotational shift around the z-axis. And (4) the eye 22 can be longitudinally misaligned by a longitudinal shift in the z-direction.

[0020] In the illustrated example, system 10 includes a laser device 15, a patient interface 20 (having an axis 25), a camera 38, a liquid dispenser / aspirator 40, and a control computer 30, which are coupled as shown. The laser device 15 includes controllable components such as a laser source 12, scanners 16, one or more optical elements 17, and / or a focusing objective lens 18, which are coupled as shown. The patient interface 20 includes a contact portion 24 (having an abutment surface 26) and a sleeve 28, which are coupled as shown. The computer 30 includes a logic 31, a memory 32 (storing a computer program 34), and a display 36, which are coupled as shown. The eye 22 has an axis 27.

[0021] In summary, system 10 aligns the eye 22 and the patient interface 20 according to the following example of operation, enabling the laser beam of the laser device 15 to treat the eye 22 according to a treatment pattern. The camera 38 records an image of the eye 22 through the patient interface 20. A liquid (e.g., a tear film) is disposed between the patient interface 20 and the outer surface of the eye 22, and the liquid contacts the patient interface 20 and the outer surface. The image includes the contour of the liquid. The display 36 displays an image of the eye. The computer 30 identifies the contour of the liquid in the image received from the camera 38, determines the misalignment of the eye 22 according to the contour, and instructs the display 36 to display an explanation of the misalignment.

[0022] Referring to the components of system 10, laser source 12 generates an ultrashort pulse laser beam. An ultrashort pulse refers to an optical pulse having a duration less than nanoseconds, such as on the order of picoseconds, femtoseconds, or attoseconds. The laser beam can have any suitable wavelength, for example, a wavelength in the range of 300 to 1500 nanometers (nm), such as 300 to 650, 650 to 1050, 1050 to 1250, and / or 1250 to 1500 nm, for example, a wavelength in the range of 340 to 350 nm, for example, 347 nm ± 1 nm. The focus of the laser beam can cause laser-induced optical breakdown (LIOB) in tissue (such as the cornea), resulting in photoablation of the tissue. The laser beam can be accurately focused to provide precise photoablation and can reduce or avoid unnecessary damage to other tissues.

[0023] Scanner 16 guides the focus of the laser beam in the transverse and longitudinal directions. The longitudinal direction refers to the propagation direction of the laser beam, also known as the z direction. The transverse direction refers to the direction perpendicular to the propagation direction of the beam, also known as the xy plane. In certain embodiments, the xyz coordinate system of laser device 15 is defined such that the contact surface 26 of patient interface 20 is the xy plane at z = 0 and the z axis where the center of contact surface 26 is (x, y) = (0, 0). Other suitable xyz coordinate systems may be used.

[0024] Scanner 16 can guide the laser beam in the transverse direction by any suitable means. For example, scanner 16 may include a pair of galvanometrically actuated scanner mirrors that can tilt about axes perpendicular to each other. As another example, scanner 16 may include an electro-optic crystal that can electro-optically manipulate the laser beam. Scanner 16 can guide the laser beam in the longitudinal direction by any suitable means. For example, scanner 16 may include a longitudinally adjustable lens, a variable refractive power lens, or a deformable mirror that can adjust the z position of the beam focus. The components of scanner 16 may be arranged along the beam path in any suitable manner, for example, within the same or different modular units.

[0025] One or more optical elements 17 direct a laser beam toward a focusing objective lens 18. The optical element 17 can act on the laser beam (e.g., act by means of transmission, reflection, refraction, diffraction, collimation, adaptation, shaping, focusing, adjustment, and / or other techniques). Examples of optical elements include lenses, prisms, mirrors, diffractive optical elements (DOEs), holographic optical elements (HOEs), and spatial light modulators (SLMs). In this example, the optical element 17 is a mirror. The focusing objective lens 18 focuses the laser beam through the patient interface 20 toward a point in the eye 22. In this example, the focusing objective lens 18 is an objective lens, for example, an fθ objective lens.

[0026] The patient interface 20 connects to the cornea of the eye 22 to couple the eye 22 to the laser device 15. In this example, the patient interface 20 has a sleeve 28 coupled to a contact portion 24. The sleeve 28 is detachably coupled to the focusing objective lens 18. The contact portion 24 may be translucent or transparent to the laser beam and has a contact surface 26 that connects to the cornea. In certain embodiments, the contact surface 26 is flat and forms a flat region on the cornea that can define the xy plane. In other embodiments, the contact surface 26 need not be flat and may be, for example, convex or concave. In certain embodiments, the patient interface 20 has rotational symmetry about an axis 25 that can be aligned with the axis 27 of the eye 22.

[0027] The camera 38 records an image of the eye 22 through the patient interface 20. Examples of the camera 38 include a video camera, an eye tracking camera, or an optical coherence tomography (OCT) camera. The camera 38 provides image data, which is the recorded image of the eye 22, to the computer 30. The computer 30 performs image processing on the image data to identify the contour of the liquid disposed between the patient interface 20 and the eye 22. The image processing includes recognizing the liquid in the recorded image, determining the contour of the liquid, and identifying the shape of the contour.

[0028] The liquid dispenser / aspirator 40 includes a dispenser and / or an aspiration device. The dispenser dispenses additional liquid onto the outer surface of the eye 22. The additional liquid may be any suitable substance such as artificial tears. In certain cases, the additional liquid may include a substance that changes the surface tension of the liquid between the eye 22 and the interface 20. For example, the surface tension may be decreased so that the liquid film spreads more easily on the interface 20. As another example, the surface tension may be increased to reduce the contour of the liquid. In certain cases, the additional liquid may include a substance for eye 22 medications, such as a substance that reduces discomfort or pain. In certain cases, the additional liquid may include a substance that enhances the visibility of the contour. For example, the additional liquid may include a dye that changes the color of the liquid to a more visible color, or a dye that includes a fluorescent tracer.

[0029] The aspiration device typically removes at least a portion of the liquid from the outer surface of the eye 22 using aspiration. The liquid dispenser / aspirator 40 may have a nozzle 42 (42a, 42b) for dispensing and / or removing the liquid. In the illustrated example, nozzle 42a dispenses the liquid and nozzle 42b removes the liquid.

[0030] The computer 30 controls the components of the system 10 according to a computer program 34. For example, the computer 30 converges the laser beam of the laser device 15 onto the eye 22 and controls the components (e.g., laser source 12, scanner 16, optical element 17, and / or focusing objective lens 18) to photoablate at least a portion of the eye 22 according to a treatment pattern. In order to successfully treat the eye 22, the eye 22 must be properly aligned with the laser beam. In order to properly align with the laser beam, the eye 22 must be properly attached to the patient interface 20, which requires proper alignment between the eye 22 and the interface 20 during docking.

[0031] In certain embodiments, computer 30 receives an image of the eye recorded by camera 38 via patient interface 20. A liquid (e.g., a tear film) is disposed between patient interface 20 and the outer surface of eye 22, and the liquid contacts interface 20 and the outer surface. The liquid forms a contour that is imaged by camera 38. (See FIG. 2A and FIG. 3 for examples of liquids between eye 20 and interface 20. However, see FIG. 3.)

[0032] In certain embodiments, computer 30 facilitates alignment of eye 22 with patient interface 20 by identifying the shape of the contour of the liquid within the image received from camera 38 and determining a misalignment of eye 22 according to the contour. Thereafter, computer 30 instructs display 36 to display an explanation of the misalignment. For example, computer 30 may identify that the contour is elliptical and determine that eye axis 27 is angled with respect to interface axis 25 (or the z-axis of laser device 15). As another example, computer 30 may determine that the centroid of the contour is not at the center point of laser device 15, and thus, that eye 22 is laterally displaced with respect to the center point of laser device 15. Examples of the relationship between the contour of the liquid and the alignment of eye 22 are described with reference to FIGS. 4A-7B.

[0033] In certain embodiments, computer 30 determines an adjustment that substantially compensates for the misalignment. For example, if eye axis 27 is angled with respect to interface axis 25 (or the z-axis of laser device 15), computer 30 may determine that rotating eye 22 will substantially compensate for the misalignment. As another example, if eye 22 is laterally displaced by a certain distance with respect to the center point of laser device 15, computer 30 may determine that, hereinafter, i.e., translating the patient interface, translating the eye, and / or translating the treatment pattern will substantially compensate for the misalignment.

[0034] In certain embodiments, after determining the adjustment, computer 30 may perform any suitable operation. For example, computer 30 may instruct display 36 to display an explanation of the adjustment. Examples of explanations of the adjustment will be described with reference to FIGS. 9A-10B. As another example, computer 30 may instruct laser device 15 to adjust patient interface 20 according to the adjustment to compensate for the inconsistency. As another example, computer 30 may instruct the automated patient bed to change the position of the patient so that eye 22 moves according to the adjustment to compensate for the inconsistency. As another example, computer 30 may adjust the treatment pattern according to the adjustment to compensate for the inconsistency.

[0035] In certain embodiments, computer 30 generates an alignment overlay indicating the desired position and shape of the contour of the liquid that aligns eye 22 and patient interface 20, and places the alignment overlay on the recorded image of eye 22 to facilitate the alignment between eye 22 and patient interface 20. Thereafter, computer 30 instructs display 36 to display the image together with the alignment overlay.

[0036] In an embodiment, the alignment overlay indicates a desired position and / or a desired shape of the contour (which may also be referred to as an “alignment position and / or alignment shape” or a “predicted position and / or predicted shape”) when the eye 22 is aligned with the interface 22. The alignment overlay may have any suitable shape or size that indicates the desired position and / or desired shape of the contour. For example, the alignment overlay may be one or more shapes that function as markers at the center of the contour of the liquid. To align the eye 22, the eye 22 may be moved relative to the interface 20 (or the interface 20 may be moved relative to the eye 22) until the center of the contour of the liquid reaches the marker. As another example, the alignment overlay may be a plurality of markers, circles, or other shapes that outline the desired contour of the liquid. To align the eye 22, the eye 22 may be moved relative to the interface 20 (or the interface 20 may be moved relative to the eye 22) until the contour of the liquid is outlined by the overlay. An example of the alignment overlay will be described with reference to FIG. 8. In a particular embodiment, the computer 30 determines the alignment overlay from the corneal topography of the eye 22. An example of the generation of such an alignment overlay will be described with reference to FIG. 13.

[0037] In a particular embodiment, the computer 30 determines a plurality of alignment overlays where each alignment overlay corresponds to a distance between the eye 22 and the patient interface 20. When the docking process reaches a certain distance, the alignment overlay corresponding to the determined distance is placed on the image. An example of such an overlay will be described with reference to FIGS. 11A - 13.

[0038] In certain embodiments, computer 30 determines the distance between eye 22 and patient interface 20 from the size of the liquid contour. After determining the distance, computer 30 may perform any suitable operation. For example, computer 30 may instruct display 36 to display the distance. As another example, computer 30 may instruct laser device 15 to adjust the actual distance according to the determined distance. For example, computer 30 may determine that patient interface 20 is too close to eye 22 and may instruct laser device 15 to move the interface away from eye 22. As another example, computer 30 may place a matching overlay corresponding to the determined distance on the image.

[0039] In certain embodiments, computer 30 performs a liquid distribution procedure to redistribute the liquid. Computer 30 may perform the procedure in any suitable manner. For example, computer 30 may instruct the user and / or laser device 15 to move patient interface closer to and / or away from eye 22. As another example, computer 30 may instruct liquid dispenser / suction device 40 to dispense additional liquid onto the outer surface of eye 22. As another example, computer 30 may instruct the suction device of liquid dispenser / suction device 40 to remove a portion of the liquid from the outer surface of eye 22.

[0040] Figures 2A and 2B show examples of liquid 50 disposed between eye 22 and patient interface 20. Figure 2A shows liquid 50 disposed between eye 22 and patient interface 20. Liquid 50 is not in contact with the contact surface 26 of patient interface 20. Camera 38 records an image of eye 22 through contact portion 24 of patient interface 20.

[0041] Figure 2B shows the liquid 50 in contact with the abutment surface 26. The adhesion force of the liquid 50 to the abutment surface 26 is stronger than the cohesive force between water molecules (also known as "capillary action") so that the liquid 50 adheres to the abutment surface 26 and forms a contour 52 that can be imaged by the camera 38. Since the shape of the contour 52 is affected by the alignment between the eye 22 and the patient interface 20, the shape can indicate the alignment between the eye 22 and the patient interface 20. Since the contour 52 can be formed on the abutment surface 26 prior to the contact between the eye 22 itself and the abutment surface, the alignment between the eye 22 and the patient interface can start prior to the contact. An example of the shape of the contour 52 will be described with reference to FIG. 3.

[0042] FIG. 3 shows examples of the shapes of the contours 52 (52a, 52b, 52c). The contour 52a has a circular shape, which may indicate that the eye 22 is aligned with the patient interface 20. The contour 52b has an elliptical shape, which may indicate that the eye axis 27 is inclined with respect to the interface axis 25. The contour 52c has a shape that is neither circular nor elliptical. That is, they have a distorted shape, which may indicate that the cornea of the eye 22 does not have a normal spherical shape, i.e., the shape is irregular. The relationship between the shape of the contour 52 and the alignment between the eye 22 and the patient interface 20 will be described in more detail with reference to FIGS. 4A to 5B.

[0043] FIGS. 4A and 4B show an example of how the circular contour 52a can indicate that the eye 22 is aligned with the patient interface 20. The circular contour 52a indicates that the distance between the patient interface 20 and the eye 22 is substantially the same at most (if not all) of the points of the contour 52a, i.e., the patient interface 20 is symmetrically aligned around the center (e.g., apex) of the cornea such that the axis 27 of the eye 22 is aligned with the axis 25 of the patient interface 20.

[0044] Figures 5A and 5B show an example of how the elliptical contour 52b can indicate that the eye axis 27 is tilted by an angle exceeding zero degrees (e.g., exceeding 3 degrees) with respect to the interface axis 25. The elliptical contour 52b shows a shape such that the corneal surface is not symmetrically aligned around the vertex of the cornea with respect to the patient interface 20, and the eye axis 27 is not aligned with the interface axis 25, i.e., the eye 22 can have rotational misalignment. It should be noted that the shape of the eye 22 (e.g., prolate or oblate) also affects the elliptical shape. Rotating the eye 22 with respect to the patient interface 20 (or the patient interface 20 with respect to the eye 22) until the contour 52 has a circular shape can compensate for the rotational misalignment.

[0045] Figures 6A and 6B show an example of how the contour 52 can be used to correct lateral misalignment. In a particular embodiment, the contour 52 has a center point 54 that should be aligned with (x,y)=(0,0) in the xyz coordinate system of the laser device 15, and the center 55 of the contact surface 26 is at (x,y)=(0,0). In some cases, the center point 54 may be the centroid of the contour 52, which is the arithmetic mean position of all points of the shape of the contour 52. In the example shown, since the contour 52 is a circular contour 52a, the center point 54 is the centroid, i.e., the center, of the circle of the contour 52a.

[0046] In the example shown, since the center point 54 is not at the center 55 of the contact surface, the patient interface 20 is laterally misaligned with the eye 22. To correct the lateral misalignment, the eye 22 may be moved laterally with respect to the patient interface 20 (or the patient interface 20 may be moved laterally with respect to the eye 22).

[0047] Figures 7A and 7B show an example of a non-regular contour 52c. The non-regular contour 52c indicates that the cornea of the eye 22 has an irregular shape. In a particular embodiment, the computer 30 determines a desired contour 52 indicating when the patient interface 20 is aligned with the eye 22 from the corneal topography of the eye 22. For example, the computer 30 may calculate the distance between a point on the patient interface 20 and a point on the cornea according to the corneal topography when the patient interface 20 and the eye 22 are aligned, and then determine the desired contour 52 of the fluid 50 according to this distance. In a particular embodiment, the computer 30 may determine different desired contours 52 at different stages of docking, for example, when docking starts and the eye 22 moves away from the patient interface 20, when docking progresses and the eye 22 approaches the patient interface 20, and when the patient interface 20 is attached to the eye 22 and docking is completed. This will be described in more detail with reference to FIG. 13.

[0048] FIG. 8 shows an example of how the alignment overlay 56 of the contour 52c can be used to correct rotational, lateral, and / or torsional misalignments. In a particular embodiment, the computer 30 may generate an alignment overlay 56 corresponding to the desired contour 50. The alignment overlay 56 can be displayed as an overlay on the recorded image, thereby enabling the camera 38 and / or the user to detect and / or correct the misalignment. In some cases, the computer 30 adds a centering point 57 to the alignment overlay 56. The centering point 57 may be located at the center 55 of the abutment surface, enabling the camera 38 and / or the user to detect and / or correct lateral misalignments. In some cases, the alignment overlay 56 may have a shape that enables the camera 38 and / or the user to identify and / or correct torsional misalignments. Otherwise, the computer 30 may add one or more markers to the alignment overlay 56 that enable the camera 38 and / or the user to detect and / or correct torsional misalignments.

[0049] Figures 9A - 10B show examples of graphical elements 58, 59, 60 that depict misalignments and adjustments for correcting misalignments. In certain embodiments, computer 30 displays graphical elements 58(58a - 58c), 59(59a - 59c) that depict the alignment or misalignment between eye 22 and patient interface 20. Graphical elements 58, 59 may have any suitable size or shape that can show the user the alignment or misalignment between eye 22 and patient interface 20. In the illustrated example, graphical element 58(58a - 58c) shows a side view of eye 22 relative to interface 20, and graphical element 59(59a - 59c) shows a top view of contour 52 of liquid 50 relative to interface 20.

[0050] In certain embodiments, computer 30 displays graphical elements 60(60a - 60e) that depict adjustments for correcting misalignments or for continuing the docking process. Graphical elements 60(60a - 60e) can assist the user in aligning eye 22 and patient interface 20. Graphical element 60 may have any suitable size or shape that can show the user the movement of patient interface 20 and / or eye 22. Examples of graphical element 60 include a pointer indicating the direction of movement (e.g., an arrow, a line, or a triangle or other polygon), a curved pointer indicating the direction of rotation, and / or text explaining the direction of movement and / or rotation.

[0051] Figure 9A shows graphical element 60a, which is a curved arrow representing a rotational movement to rotate eye 22 to align eye axis 27 and interface axis 25 to correct rotational misalignment. Figure 9B shows graphical element 60b, which is an arrow representing a translational movement to move the center point of contour 52 towards center 55 of the contact surface. Figure 9C shows graphical element 60c, which is an arrow representing a longitudinal movement to bring eye 22 closer to patient interface 20.

[0052] Figure 10A shows a graphical element 60d indicating two types of movements. The straight arrow represents a translational movement that moves the center point 54 of the contour 52 towards the centering point 57 of the alignment overlay 56, and the curved arrow represents a rotational movement in the xy plane to correct the torsional misalignment. Figure 10B shows a graphical element 60e which is an arrow representing the translational movement that moves the center point 54 of the contour 52 towards the centering point 57 of the alignment overlay 56.

[0053] Figures 11A - 13 show examples of the relationship between the contour 52 of the liquid 50 and the distance d between the patient interface 20 and the eye 22. In this example, the patient interface 20 has a flat contact surface. A patient interface 20 with a different shaped contact surface may result in a contour 52 of a different shape and / or size.

[0054] Figures 11A and 11B show the contour 52 at distances d1 and d2, where d1 > d2. The distance d may be measured by any suitable method. For example, the distance d may be measured as the distance between the patient interface 20 (e.g., the contact surface 16) and the base of the cornea (where the cornea touches the sclera) or other suitable part of the cornea. Generally, the contour 52 becomes smaller as the distance d increases and larger as the distance d decreases. That is, the contour 52 becomes larger as the eye 22 and the interface 20 approach each other. In this example, the contour 52 is small at distance d1 and large at distance d2. The size of the contour 52 may be measured by any suitable method. For example, the size of the contour 52 may be calculated from, for example, the area delimited by the contour 52 or the diameter of the contour 52.

[0055] Figures 12A - 12C show the contour 52 at distances d1, d2, and d3, where d1 > d2 > d3. In this example, the contour 52 is small at distance d1, large at distance d2, and even larger at distance d3. In this example, the distance d1 may be the distance before contact between the eye 22 and the interface 20.

[0056] In certain embodiments, computer 30 calculates distance d from the size of contour 52. For example, computer 30 determines the relationship between the size of contour 52 and distance d. The relationship may be determined, for example, from the average of previous measurements of size and distance, or from the corneal topography of eye 22. Thereafter, computer 30 measures the size of the contour and determines the distance from the size and the relationship.

[0057] FIG. 13 shows different alignment overlays 56 for different distances d between patient interface 20 and eye 22. In certain embodiments, computer 30 determines a desired contour 52 (indicating when patient interface 20 is aligned with eye 22) from the corneal topography of eye 22. The corneal topography of eye 22 generally depicts the anterior shape of the cornea. This shape can be converted to the xyz coordinate system of laser device 15 so that the xy coordinates of the surface of the cornea for different z values can be determined. Using this information, computer 30 predicts the location on the surface of the cornea that contacts abutment plate 26 when abutment plate 26 applies pressure to the cornea during docking. The predicted contour 52 delimits the location on the surface of the cornea that contacts abutment plate 26. The predicted contour can function as the desired contour 52.

[0058] In certain embodiments, computer 30 may determine different desired contours 52 at different stages of docking, such as when docking starts and patient interface 20 moves away from eye 22, when docking progresses and patient interface 20 approaches eye 22, and when patient interface 20 is attached to eye 22 and docking is complete. For example, computer 30 may predict a contour 52 that delimits the location on the surface of the cornea that contacts abutment plate 26 for each distance d between patient interface 20 and eye 22 according to the corneal topography of eye 22.

[0059] Computer 30 may also display alignment overlays 56 (56a - 56d) corresponding to a desired contour 52 at each distance d during different stages of docking. In the illustrated example, alignment overlay 56a represents the desired contour 52 at distance d1 when the eye first contacts the patient interface 20. Alignment overlay 56b represents the desired contour 52 at distance d2 when the eye approaches the patient interface 20. Alignment overlay 56c represents the desired contour 52 at distance d3 when applanation of the eye by the patient interface 20 progresses. Alignment overlay 56d represents the desired contour 52 at distance d4 when docking is complete.

[0060] In other examples, the contour 52 may be formed on the contact surface 26 prior to contact between the eye 22 itself and the contact surface. In the example, the computer 30 determines the alignment overlay 56 corresponding to the desired contour 52 prior to contact, so the alignment between the eye 22 and the patient interface 20 can start prior to contact.

[0061] FIG. 14 shows an example of a method for aligning the eye 22 and the patient interface 20 that may be implemented by the system 10 of FIG. 1. The method starts with step 100 in which the camera 38 records an image of the eye 22 along with the liquid 50 through the patient interface 20. A liquid (e.g., a tear film) 50 is disposed between the patient interface 20 and the outer surface of the eye 22 and contacts the patient interface 20 and the outer surface. The image includes the contour 52 of the liquid 50.

[0062] In operation 102, the liquid 50 can be redistributed. For example, if the contour 52 cannot be imaged by the camera 38, the liquid 50 can be redistributed. If the liquid 50 is not redistributed, the method proceeds to operation 106. If the liquid 50 is redistributed, the method proceeds to operation 104 where the liquid 50 is redistributed. The computer 30 may perform the liquid distribution procedure in any suitable manner to redistribute the liquid 50. For example, the computer 30 may instruct the user and / or the laser device 15 to move the patient interface 20 closer to and / or away from the eye 22 one or more times. As another example, the computer 30 may instruct the user and / or the dispenser of the liquid dispenser / suction device 40 to dispense additional liquid onto the outer surface of the eye 22. As another example, the computer 30 may instruct the user and / or the suction device of the liquid dispenser / suction device 40 to remove a portion of the liquid from the outer surface of the eye 22. After the liquid 50 has been redistributed, the method proceeds to operation 106.

[0063] The computer 30 monitors an image of the eye 22 in operation 106 and determines the distance d between the patient interface 20 and the eye 22 in operation 108. In certain embodiments, the computer 30 may determine the distance d from the size of the contour 52. In certain embodiments, the computer 30 may instruct the display screen 36 to display the distance d. In certain embodiments, the computer 30 may adjust the distance d according to the determined distance d.

[0064] In step 110, computer 30 generates a registration overlay 56. In certain embodiments, computer 30 may generate a registration overlay 56 that represents a desired contour 52 of the liquid. In certain embodiments, computer 30 determines the registration overlay 56 from the corneal topography of eye 22. In certain embodiments, computer 30 determines a plurality of registration overlays 56 where each registration overlay 56 corresponds to a distance d between eye 22 and patient interface 20. When the docking process reaches a particular distance, the registration overlay 56 corresponding to this distance is placed on the image. Computer 30 instructs display 36 to display an image of eye 22 together with registration overlay 56 in step 112. In step 114, eye 22 is moved towards patient interface 20, or patient interface 20 is moved towards eye 22. The relative movement may be performed in any suitable manner. For example, the relative movement may be performed in any suitable order in the xy directions, torsionally, and / or in the z direction.

[0065] In step 116, misalignment may exist. In certain embodiments, computer 30 identifies contour 52 within the image and determines a misalignment of eye 22 from contour 52. For example, computer 30 may identify that contour 52 is elliptical and determine that the eye axis 27 is angled with respect to the interface axis 25. As another example, computer 30 may determine that the center of gravity of contour 52 is not at the center point of laser device 15, and thus determine that eye 22 is laterally displaced with respect to the center point of laser device 15.

[0066] In the absence of misalignment, the method proceeds to step 128 and flattening can be completed. In the presence of misalignment, the computer 30 instructs the display 36 to display an explanation of the misalignments 58, 59 in step 118. The computer 30 determines an adjustment to compensate for the misalignment in step 120. In certain embodiments, the computer 30 determines an adjustment that substantially compensates for the misalignment. For example, if the eye axis 27 is angled with respect to the interface axis 25, the computer 30 may determine that rotating the eye 22 will substantially compensate for the misalignment. As another example, if the eye 22 is laterally displaced by a certain distance with respect to the center point of the laser device 15, the computer 30 may determine that the misalignment is substantially compensated by one or more of the following: translating the patient interface 20 by the determined distance, translating the eye 22 towards the center point by the determined distance, and / or translating the treatment pattern by the determined distance.

[0067] The computer 30 displays an explanation of the adjustment 60 in step 124. An adjustment to compensate for the misalignment can be made in step 126. For example, the computer 30 may instruct the laser device 15 to adjust the patient interface 20 according to the adjustment to compensate for the misalignment. As another example, the computer 30 may instruct the automatic patient bed to change the patient's position so that the eye 22 moves according to the adjustment to compensate for the misalignment. As another example, the computer 30 may adjust the treatment pattern according to the adjustment to compensate for the misalignment.

[0068] In step 128, flattening can be completed. If flattening is not completed, the method returns to step 102 and it may be necessary to dispense the liquid 50. If flattening is completed, the method proceeds to step 130 and the docking procedure is completed. At this point, the method ends.

[0069] The components of the systems and apparatuses disclosed herein (e.g., computer 30) may include an interface, logic, and / or memory, any of which may include computer hardware and / or software. An interface (e.g., display 36) can receive input to and / or transmit output from a component, and is typically used to exchange information among software, hardware, peripherals, users, and combinations thereof. A user interface (e.g., a graphical user interface (GUI)) is a type of interface that can be utilized by a user to interact with a computer. Examples of user interfaces include display screens, touchscreens, keyboards, mice, gesture sensors, microphones, and speakers.

[0070] Logic can execute the operations of a component. Logic can include one or more electronic devices that process data, e.g., execute instructions to generate output from input. Examples of such electronic devices include computers, processors, microprocessors (e.g., central processing units (CPUs)), and computer chips. Logic can include computer software that encodes instructions executable by an electronic device to perform the operations. Examples of computer software include computer programs, applications, and operating systems.

[0071] The memory can store information and may include tangible computer-readable and / or computer-executable storage media. Examples of memory include computer memory (e.g., random access memory (RAM) or read-only memory (ROM)), mass storage media (e.g., hard disk), removable storage media (e.g., compact disk (CD) or digital video or versatile disk (DVD)), databases, network storage (e.g., server), and / or other computer-readable media. Certain embodiments can be directed to memory encoded with computer software.

[0072] Although the present disclosure has been described with respect to specific embodiments, modifications of the embodiments (e.g., changes, substitutions, additions, omissions, and / or other modifications) will be apparent to those skilled in the art. Accordingly, modifications can be made to the embodiments without departing from the scope of the invention. For example, modifications can be made to the systems and devices disclosed herein. As will be apparent to those skilled in the art, the components of the systems and devices may be integrated or separated, or the operations of the systems and devices may be performed by more, fewer, or other components. As another example, modifications can be made to the methods disclosed herein. As will be apparent to those skilled in the art, the methods may include more, fewer, or other steps, and the steps may be performed in any suitable order.

[0073] To assist the Patent Office and the reader in interpreting the claims, the applicant notes that unless the words "means for" or "step for" are expressly used in a particular claim, none of the claims or claim elements are intended to evoke 35 U.S.C. § 112(f). The use of other terms in the claims (e.g., "mechanism," "module," "device," "unit," "component," "element," "member," "apparatus," "machine," "system," "processor," or "controller") is understood by the applicant to refer to structures known to one of ordinary skill in the relevant art and is not intended to evoke 35 U.S.C. § 112(f).

Claims

1. A system for aligning an eye with a patient interface of a laser device, comprising: A camera configured to record a plurality of images of the eye through the patient interface of the laser device, wherein a liquid is disposed between the patient interface and the outer surface of the eye, the liquid contacts the patient interface and the outer surface of the eye, and the images include the contour of the liquid; A display screen configured to display the images of the eye; A computer configured to align the eye with the patient interface to align the eye with a laser beam of the laser device, wherein the eye is aligned to treat the eye according to a treatment pattern, and the computer is configured to: Identify the contour of the liquid in the images received from the camera; Determine a misalignment of the eye according to the contour; Instruct the display screen to display an explanation of the misalignment; Thereby configured to align the eye with the patient interface. A computer; A system comprising the above.

2. The computer is configured to: Identify that the shape of the contour is elliptical; Determine that the axis of the eye is angled with respect to the z-axis of the laser device; Thereby configured to determine the misalignment of the eye according to the contour. The system according to claim 1.

3. The computer is configured to: Determine that the centroid of the shape of the contour is not at the center point of the laser device; and Determine that the eye is laterally displaced with respect to the center point of the laser device; Thereby configured to determine the misalignment of the eye according to the contour. The system according to claim 1.

4. The computer is configured to: Determine an adjustment to substantially compensate for the misalignment. The system according to claim 1.

5. The computer is configured to: Identify that the shape of the contour is elliptical; In response to the identification of the shape, determine that the axis of the eye is angled with respect to the z-axis of the laser device; Determine that the misalignment is substantially compensated when the eye is rotated; Thereby configured to determine the adjustment to substantially compensate for the misalignment. The system according to claim 4.

6. The computer is configured to: determining that the center of gravity of the shape of the contour is not at the center point of the laser device; determining that the eye is laterally displaced by a certain distance with respect to the center point of the laser device; determining that the misalignment is substantially compensated when the eye is translated towards the center point by the determined distance The system according to claim 4, wherein the adjustment for substantially compensating the misalignment is determined by: **Claim 7** The computer is configured to: The system according to claim 4, wherein the computer is configured to instruct the display screen to display an explanation of the adjustment. **Claim 8** The computer is configured to: The system according to claim 4, wherein the computer is configured to adjust the patient interface or the eye according to the adjustment for compensating the misalignment. **Claim 9** The computer is configured to: The system according to claim 4, wherein the computer is configured to adjust the treatment pattern according to the adjustment for compensating the misalignment. **Claim 10** The computer is configured to: generate an alignment overlay indicating a desired position and a desired shape of the contour for aligning the eye and the patient interface; place the alignment overlay on the image; instruct the display screen to display the image together with the alignment overlay The system according to claim 1, wherein the system is configured to: **Claim 11** The computer is configured to: receive a depiction of the corneal topography of the eye; determine the desired position and the desired shape of the contour for aligning the eye and the patient interface according to the corneal topography of the eye The system according to claim 10, wherein the system is configured to: **Claim 12** The computer is configured to: determine a plurality of alignment overlays, each alignment overlay corresponding to a specific distance between the eye and the patient interface; determine the distance between the eye and the patient interface; generate the alignment overlay corresponding to the determined distance The system according to claim 10, wherein the system is configured to: **Claim 13** The computer is configured to: The system according to claim 1, wherein the computer is configured to determine the distance between the eye and the patient interface according to the size of the contour. **Claim 14** The system according to claim 13, wherein the computer is configured to instruct the display screen to display the distance between the eye and the patient interface.

15. The system according to claim 13, wherein the computer is configured to adjust the distance of the eye from the patient interface according to the determined distance between the eye and the patient interface.

16. The computer is configured to move the patient interface away from the eye, and to move the patient interface closer to the eye to perform a liquid dispensing procedure for redistributing the liquid, as claimed in claim 1.

17. The system further includes a dispenser configured to dispense additional liquid onto the outer surface of the eye, and the computer is configured to instruct the dispenser to dispense the additional liquid onto the outer surface of the eye. The system according to claim 1.

18. The system according to claim 17, wherein the additional liquid includes a substance capable of changing the surface tension of the liquid.

19. The system according to claim 17, wherein the additional liquid includes a substance for enhancing the visibility of the liquid.

20. The system further includes a suction device configured to remove at least a portion of the liquid from the outer surface of the eye, and the computer is configured to instruct the suction device to remove at least the portion of the liquid from the outer surface of the eye. The system according to claim 1.

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