Head support for an ophthalmic imaging instrument

Abstract

The present application relates to a head support for an ophthalmic imaging instrument. The ophthalmic imaging instrument is for imaging an eye of a subject and comprises a patient interface with which a face of the subject's head is to engage during imaging of the eye, the patient interface being arranged to secure an orientation of the head relative to the ophthalmic imaging instrument by contacting a first portion of the face that overlies a frontal bone of the head and respective second portions of the face that overlie each of the malar bones of the head when the subject's face is engaged with the patient interface. The ophthalmic imaging instrument further comprises an image acquisition device arranged to acquire an image of the eye when the subject's face is engaged with the patient interface.

Description

[0001] field The examples in this article generally relate to the field of ophthalmic imaging instruments, and more specifically to a patient interface for such instruments, in which the subject's head engages with the patient interface during imaging of the subject's eye. background Ophthalmic imaging equipment employs various imaging techniques to image different parts of the eye and is used by clinicians to diagnose and manage various eye conditions. Ophthalmic imaging equipment includes (but is not limited to) scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT) imaging equipment, fundus cameras, micro-field measurement equipment, and corneal topography equipment (and other equipment), or combinations of two or more such devices.

[0002] Ophthalmic imaging devices typically include a patient interface (also known as a face interface or head support), such as a chin rest, headrest, or eye cup, which has a contact surface that the patient's head contacts during imaging of the patient's eye. The patient interface allows the eye to be positioned approximately correctly relative to the ophthalmic imaging device and helps keep the subject's head stable during imaging, thereby reducing artifacts in the acquired images caused by movement of the patient's head relative to the device. Providing a patient interface that effectively keeps the subject's head stable is particularly important for ophthalmic imaging devices that require relatively long imaging sessions (which can last from tens of seconds to several minutes, depending on the device), such as microperimeters and optical coherence tomography (OCT) imaging devices, where eye movement during imaging can cause motion artifacts in the acquired eye images.

[0003] Overview According to a first exemplary aspect of this document, an ophthalmic imaging instrument is provided for imaging the eyes of a subject. The ophthalmic imaging instrument includes a patient interface in which the subject's face engages during eye imaging. The patient interface is arranged such that, when the subject's face engages with the patient interface, the orientation of the head relative to the ophthalmic imaging instrument is fixed by contacting a first portion of the face covering the frontal bone of the head and corresponding left and right portions of the face covering each zygomatic bone of the head. The ophthalmic imaging instrument also includes an image acquisition device arranged to acquire an image of the eye while the subject's face engages with the patient interface.

[0004] In some example embodiments, the patient interface is arranged to avoid contact with the subject's nose and a third portion of the face covering the maxilla when the subject's face engages with the patient interface. The patient interface may also be arranged to avoid contact with the subject's chin. For example, the patient interface may not include a chin rest, such that the subject's chin is not contacted by the patient interface when the subject engages with it. In these example embodiments, the patient interface may have an elongated (and preferably continuous) contact surface including a central portion arranged to contact a first portion of the face when the subject's face engages with the patient interface, the contact surface continuously (preferably downward only) extending to each of a first end portion and a second end portion of the contact surface, the first and second end portions being arranged to contact the left and right sides of the face, respectively, when the subject's face engages with the patient interface. In this case, the end portions of the contact surface may be immovable (or fixed) relative to the central portion of the contact surface, and the patient interface is rigid. The patient interface can alternatively be configured to deform, for example, bend and / or plastically indent, when engaging with the subject's face, wherein the end portions of the contact surface move relative to the central portion of the contact surface due to the subject's face; in this case, the shape of the contact surface can be changed solely by pressure applied to the parts of the contact surface.

[0005] The elongated contact surface may further include a first arcuate portion and a second arcuate portion extending from opposite ends of the central portion, each of the first and second arcuate portions extending along a corresponding arcuate path from a corresponding end of the central portion to a corresponding one of the first and second end portions, the corresponding arcuate path being sized to surround the subject's eye socket when the subject's face engages with the patient interface. The first end portion of the contact surface may be located at an end of the first arcuate portion remote from the central portion, and the second end portion of the contact surface may be located at an end of the second arcuate portion remote from the central portion.

[0006] Alternatively or additionally, the first and second bow-shaped portions may be arranged such that a gap is provided between the first and second end portions, wherein the subject's nose can be accommodated within the gap without being contacted by the patient interface when the subject's face engages with the patient interface.

[0007] In the ophthalmic imaging apparatus of the first example aspect or any of the above example embodiments, the patient interface may be oriented such that when the subject tilts forward from an upright sitting position to engage with the patient interface, the subject's head has a downward tilt that is greater than the tilt of the head when in an upright sitting position (e.g., greater by 10 to 20 degrees, and preferably greater by 12 to 17 degrees).

[0008] Additionally or alternatively, according to another example embodiment, the image acquisition device may include an objective lens that is movable toward and away from the eye along a movement axis when the subject's face engages with the patient interface, and the patient interface may be arranged to fix the orientation of the head relative to the movement axis, such that the objective lens can be moved along the movement axis to a position for acquiring an image of the eye. The ophthalmic imaging instrument of this other example embodiment may be one of a wide-field ophthalmic imaging instrument and an ultra-wide-field ophthalmic imaging instrument. In a variation of the ophthalmic imaging instrument of this other example embodiment, the ophthalmic imaging instrument may further include: a base on which the image acquisition device is slidably mounted; and a gantry extending from the base and supporting the patient interface, wherein the image acquisition device is slidable relative to the base to move the objective lens toward and away from the eye along the movement axis when the subject's face engages with the patient interface. In a variation of the ophthalmic imaging instrument of this other example embodiment, the objective lens may be movable in a lateral direction, such that the objective lens can be moved and / or laterally aligned between a left-eye imaging position and a right-eye imaging position to image the subject's eye.

[0009] Additionally or alternatively, the ophthalmic imaging instrument of this other example embodiment or a variant thereof may also include a stereo camera ranging system for measuring the distance between the objective lens and the eye. The stereo camera ranging system includes a first camera and a second camera arranged to image the eye from different positions relative to the objective lens, and the patient interface may be arranged to fix the orientation of the head relative to the ophthalmic imaging instrument such that when the subject's face engages with the patient interface, each of the first camera and the second camera has a corresponding field of view of the eye that is not obscured by the subject's facial features.

[0010] In the first example aspect or in any of the above-described example embodiments and variations of ophthalmic imaging instruments, the patient interface may be operable to fix the orientation of the head relative to the ophthalmic imaging instrument in a first relative orientation for imaging the subject's right eye by the ophthalmic imaging instrument and a second relative orientation for imaging the subject's left eye by the ophthalmic imaging instrument, the second relative orientation being different from the first relative orientation. In this case, and in cases where the ophthalmic imaging instrument has features of a variation of another example embodiment described above, the frame may include a curved guide rail, and the patient interface may be slidably mounted on the curved guide rail so as to be movable between: a first position on the guide rail, in which the patient interface is arranged to fix the orientation of the head relative to the ophthalmic imaging instrument in the first relative orientation for imaging the subject's right eye; and a second position on the guide rail (different from the first position), in which the patient interface is arranged to fix the orientation of the head relative to the ophthalmic imaging instrument in the second relative orientation for imaging the subject's left eye. Ophthalmic imaging instruments may also include a drive mechanism with a Bowden cable arranged to move the patient interface between a first position on an arcuate guide and a second position on the arcuate guide.

[0011] In the first example aspect or in any of the above-described example embodiments and variations of ophthalmic imaging instruments, the patient interface may include at least one compressible contact member arranged to contact a first portion of the face and each second portion of the face when the subject's face engages with the patient interface. The image acquisition device may be an optical coherence tomography (OCT) image acquisition device arranged to acquire at least one of, for example, an OCT image of the retina of the eye, an OCT angiographic image of the retina, or an OCT image of the anterior segment of the eye.

[0012] According to a second exemplary aspect of this document, a patient interface attachable to an ophthalmic imaging instrument is provided, wherein, when the patient interface is attached to the ophthalmic imaging instrument and engages with the face of a subject, the patient interface is arranged to fix the position and orientation of the subject's head relative to the ophthalmic imaging instrument by contacting a first portion of the face covering the frontal bone of the head and corresponding left and right portions of the face covering each cheekbone of the head, such that the ophthalmic imaging instrument can acquire images of the eyes.

[0013] In some example embodiments, the patient interface can be arranged to avoid contact with the subject's nose and a third portion of the face covering the maxilla of the head when the subject's face engages with the patient interface. The patient interface may have an elongated (and preferably continuous) contact surface including a central portion arranged to contact a first portion of the face when the subject's face engages with the patient interface, the contact surface extending (and preferably not less than) each of a first end portion and a second end portion of the contact surface arranged to contact a second portion of the face, respectively, when the subject's face engages with the patient interface. For example, the elongated and preferably continuous contact surface may be the surface of a single molded or extruded piece. Furthermore, the end portions of the contact surface may be immovable (or fixed) relative to the central portion of the contact surface, and the patient interface is rigid. The patient interface can alternatively be configured to deform, for example, bend and / or plastically indent, when engaging with the subject's face, wherein the end portions of the contact surface move relative to the central portion of the contact surface due to the subject's face; in this case, the shape of the contact surface can be changed solely by pressure applied to the parts of the contact surface.

[0014] The elongated contact surface may further include a first and a second arched portion extending from opposite ends of a central portion, each of the first and second arched portions extending along a corresponding arched path from a corresponding end of the central portion to a corresponding one of the first and second end portions, the respective arched path being sized to surround the subject's eye socket when the subject's face engages with the patient interface. The first end portion of the contact surface may be located at an end of the first arched portion remote from the central portion, and the second end portion of the contact surface may be located at an end of the second arched portion remote from the central portion. Additionally or alternatively, the first and second arched portions may be arranged such that a gap is provided between the first and second end portions, wherein, when the subject's face engages with the patient interface, the subject's nose can be accommodated within the gap without being contacted by the patient interface.

[0015] According to a third exemplary aspect of this document, an ophthalmic imaging instrument is provided for imaging the eyes of a subject, the ophthalmic imaging instrument having a patient interface attached to the second exemplary aspect described above or any exemplary embodiment thereof, the ophthalmic imaging instrument including an image acquisition device arranged to acquire an image of the eyes when the subject's face engages with the patient interface.

[0016] In the ophthalmic imaging instrument of the third example aspect, the patient interface can be oriented such that when the subject tilts forward from an upright sitting position to engage with the patient interface, the subject's head has a downward tilt that is greater than the tilt of the head when in an upright sitting position (e.g., greater by 10 to 20 degrees, and preferably greater by 12 to 17 degrees).

[0017] Additionally or alternatively, in the ophthalmic imaging apparatus of the third example aspect, according to the example embodiment, the image acquisition device may include an objective lens that is movable toward and away from the eye along a movement axis when the subject's face engages with the patient interface, and the patient interface may be arranged to fix the orientation of the head relative to the movement axis, such that the objective lens can be moved along the movement axis to a position for acquiring an image of the eye. The ophthalmic imaging apparatus may be one of a wide-field ophthalmic imaging apparatus and an ultra-wide-field ophthalmic imaging apparatus. The ophthalmic imaging apparatus may further include: a base on which the image acquisition device is slidably mounted; and a frame extending from the base and supporting the patient interface, wherein the image acquisition device is slidable relative to the base to move the objective lens toward and away from the eye along the movement axis when the subject's face engages with the patient interface. In a variation of the ophthalmic imaging apparatus of this other example embodiment, the objective lens may be movable in a lateral direction, such that the objective lens can be moved and / or laterally aligned between a left-eye imaging position and a right-eye imaging position to image the subject's eye.

[0018] Additionally or alternatively, the ophthalmic imaging instrument of the third example aspect may also include a stereo camera ranging system for measuring the distance between the objective lens and the eye, the stereo camera ranging system including a first camera and a second camera arranged to image the eye from different positions relative to the objective lens, and the patient interface may be arranged to fix the orientation of the head relative to the ophthalmic imaging instrument such that when the subject's face engages with the patient interface, each of the first camera and the second camera has a corresponding field of view of the eye that is not obscured by the subject's facial features.

[0019] In the ophthalmic imaging apparatus of the third example aspect or any of the above example embodiments, the patient interface may be operable to fix the orientation of the head relative to the ophthalmic imaging apparatus to a first relative orientation for imaging the subject's right eye by the ophthalmic imaging apparatus and a second relative orientation for imaging the subject's left eye by the ophthalmic imaging apparatus, the second relative orientation being different from the first relative orientation. In this configuration, and where the ophthalmic imaging instrument includes a base and a frame, the image acquisition device is slidably mounted on the base; the frame extends from the base and supports the patient interface, wherein the image acquisition device is slidable relative to the base to move the objective lens along a movement axis toward and away from the eye when the subject's face engages with the patient interface. The frame may include an arcuate guide rail, and the patient interface may be slidably mounted on the arcuate guide rail to be movable between: a first position on the guide rail, in which the patient interface is arranged to fix the head in a first relative orientation relative to the ophthalmic imaging instrument for imaging the subject's right eye; and a second position on the guide rail (different from the first position), in which the patient interface is arranged to fix the head in a second relative orientation relative to the ophthalmic imaging instrument for imaging the subject's left eye. The ophthalmic imaging instrument may also include a drive mechanism with a Bowden cable arranged to move the patient interface between the first position on the arcuate guide rail and the second position on the arcuate guide rail.

[0020] In the ophthalmic imaging apparatus of the third example aspect or any of the above example embodiments, the patient interface may include at least one compressible contact member arranged to contact a first portion and each second portion of the face when the subject's face engages with the patient interface. The image acquisition device may be an OCT image acquisition device arranged to acquire at least one of, for example, an OCT image of the retina of the eye, an OCT angiographic image of the retina, or an OCT image of the anterior segment of the eye.

[0021] According to a fourth exemplary aspect of this document, a method for imaging a subject's eye using an ophthalmic imaging instrument, wherein the ophthalmic imaging instrument includes a patient interface, and during imaging of the subject's eye, the subject's head and face are engaged with the patient interface, the method comprising: engaging the subject's head and face with the patient interface; fixing the subject's head in an orientation relative to the ophthalmic imaging instrument by contacting the upper portion of the face covering the frontal bone of the head and the corresponding left and right portions of the face covering each zygomatic bone of the head when the subject's face is engaged with the patient interface; and acquiring an image of the eye while the subject's head and face are engaged with the patient interface.

[0022] In some example embodiments, the ophthalmic imaging instrument may include an objective lens that can move toward and away from the eye along a movement axis when the subject's face is engaged with the patient interface, wherein fixing the subject's head may include fixing the orientation of the head relative to the movement axis and moving the objective lens along the movement axis to an imaging position to obtain an image of the eye.

[0023] Additionally or alternatively, the method may further include imaging the subject's eyes, wherein: fixing the patient's head in an orientation relative to an ophthalmic imaging instrument includes: fixing the head in a first relative orientation to image the subject's first eye by the ophthalmic imaging instrument; and fixing the head in a second relative orientation to image the subject's second eye by the ophthalmic imaging instrument.

[0024] In some example embodiments, securing the head in a second relative orientation may include moving the patient interface from a first position to a second position. Moving the patient interface from the first position to the second position may include sliding the patient interface along an arcuate path such that when the patient interface is in the first position, the patient interface is oriented at a first angle relative to the axis of movement of the objective lens, and when the patient interface is in the second position, the patient interface is oriented at a second angle relative to the axis of movement of the objective lens, wherein the first angle is different from the second angle.

[0025] In some example embodiments, the method may further include moving an objective lens from a retracted position to an imaging position while the subject's head is fixed in an orientation relative to an ophthalmic imaging instrument. Moving the objective lens from the retracted position to the imaging position may include acquiring an image of the anterior region of the eye, determining, based on the acquired image, the distance between the anterior region of the eye and the ophthalmic imaging instrument and / or the objective lens, and moving the objective lens to the imaging position based on the determined distance. The anterior region of the eye may be, for example, the subject's pupil. The method may include using a camera to acquire an image of the anterior region of the eye and monitoring the acquired image to detect occlusion of the visual field of the anterior region of the eye by facial anatomical features. The method may further include changing the orientation of the patient interface if occlusion is present in the image acquired by the camera.

[0026] In some example embodiments, the method may include monitoring the distance between the objective lens and the subject's face as the objective lens is moved from the retracted position to the imaging position, and stopping the movement of the objective lens from the retracted position to the imaging position if a collision is predicted, and / or alerting the user of the ophthalmic imaging instrument that a collision has been predicted.

[0027] In some example embodiments, engaging the subject’s face with the patient interface may include tilting the subject’s head downwards before engaging the patient interface, such that the subject’s head has a downward tilt that is greater than the tilt of the head when in an upright sitting position (e.g., 10 to 20 degrees greater, and preferably 12 to 17 degrees greater). Brief description of the attached diagram Exemplary embodiments will now be explained in detail with reference to the accompanying drawings described below, by way of non-limiting example only. Unless otherwise indicated, similar reference numerals appearing in different figures in the drawings may denote the same elements or elements that are functionally similar.

[0028] Figure 1 This is a side view of an ophthalmic imaging instrument according to an example embodiment of this article.

[0029] Figure 2 This is an end view of an ophthalmic imaging instrument, as described in the example embodiments of this article, taken from the end where the subject is located during imaging.

[0030] Figure 3 This is a top view of the rack and patient interface of an example embodiment.

[0031] Figure 4 This is an end view of an ophthalmic imaging instrument of an example embodiment of this document, viewed from the end where the subject is located during imaging, with the patient interface in a first position.

[0032] Figure 5 This is an end view of an ophthalmic imaging instrument of an example embodiment of this article, viewed from the end where the subject is located during imaging, with the patient interface in a second position.

[0033] Figure 6 This is a perspective view of the frame and patient interface of an ophthalmic imaging instrument according to an example embodiment.

[0034] Figure 7 This is another perspective view of the rack and patient interface of the ophthalmic imaging instrument of the example embodiment, showing a cross-section of the rack and patient interface.

[0035] Figure 8 This is an end view of the patient interface of an example embodiment, viewed from the end where the subject is located during imaging.

[0036] Figure 9 This is a side view of the patient interface in an example embodiment.

[0037] Figure 10 This is a top view of the patient interface in an example embodiment.

[0038] Figure 11 This is a flowchart outlining a method for imaging a subject's eye using ophthalmic imaging instruments.

[0039] Figure 12 This is a flowchart outlining a method for imaging a subject's eyes using ophthalmic imaging instruments.

[0040] Detailed description of example embodiments Conventional patient interfaces typically include a forehead rest and a chin rest to help stabilize the subject's head during imaging, while allowing the head to rotate about these pivot points, and the subject is usually instructed to remain as still as possible to minimize this rotation. However, this is often insufficient, and involuntary movements of the patient frequently occurring during imaging result in images of lower quality than could otherwise be achieved. In view of these drawbacks of conventional patient interfaces, the inventors have devised a patient interface arranged to suppress the rotational degrees of freedom in the aforementioned head movements, and thus fix the orientation of the subject's head relative to the ophthalmic imaging instrument. The patient interface of the example embodiment described herein achieves this by contacting not only a first portion of the face covering the frontal bone of the head (e.g., thus contacting the subject's forehead) but also a corresponding second portion of the face covering each zygomatic bone (i.e., the cheekbone) when engaging with the patient interface. Therefore, the patient interface can securely contact the subject's head in three distinct contact areas because the soft tissue covering the frontal and zygomatic bones is relatively thin. Furthermore, these contact areas are widely spaced, and thus provide excellent head stability during imaging of the eye. These exemplary embodiments will now be described in more detail with reference to the accompanying drawings.

[0041] Figure 1 This is a schematic side view of an ophthalmic imaging instrument 10 according to an example embodiment, which is configured to image the eye 30 of a (human, typically adult) subject 32. Figure 2 This is an end view of the ophthalmic imaging instrument 10, which in this case is obtained from the perspective of the subject 32. Figure 3 This is a top view of the ophthalmic imaging instrument 10. The ophthalmic imaging instrument 10 includes a patient interface 12 (which may also be referred to as a head support or head stabilizer), with the subject's face 34 engaging with the patient interface 12 during imaging of the eyes 30, thereby facilitating head 36 stability during imaging. The ophthalmic imaging instrument 10 also includes an image acquisition device 14 arranged to acquire one or more images of the eyes 30 while the subject's face 34 is engaged with the patient interface 12.

[0042] Image acquisition device 14 can take various forms. For example, as in this example embodiment, image acquisition device 14 can be an optical coherence tomography (OCT) imaging device in the form of a swept-source OCT (SS-OCT) imaging device, having known components such as a beam generator, scanning system, interferometer, photodetector, OCT data processing hardware, and objective system (or "objective"). The scanning system can be arranged to perform one-dimensional and / or two-dimensional point scanning of the beam on the retina of the eye 30 and collect light that has been scattered by the retina during point scanning. Thus, image acquisition device 14 can acquire A scans distributed on the surface of the retina by sequentially illuminating the scanning positions with the beam (one scan position at a time) and collecting at least some of the light scattered by the retina at each scanning position. Image acquisition device 14 can be arranged to acquire OCT images in the form of B scans by performing point scanning to acquire consecutive A scans, for example, along a straight line. However, alternatively, image acquisition device 14 can be arranged to acquire B scans by performing a scanning system that performs line scanning using hardware well known to those skilled in the art. More generally, the image acquisition device 14 can be arranged to perform point scanning or line scanning using a predetermined scanning pattern (e.g., spiral scanning) known to those skilled in the art, or to acquire OCT images in the form of B-scan or C-scan by employing a full field-of-view setup.

[0043] However, the image acquisition device 14 can be another Fourier domain OCT (FD-OCT) imaging device, such as a spectral domain OCT (SD-OCT) imaging device, or alternatively a time domain OCT (TD-OCT) imaging device. However, the image acquisition device 14 is not limited to this and can be any other type of ophthalmic image acquisition device for imaging the posterior segment of the eye 30, such as a scanning laser ophthalmoscopy (SLO) or fundus camera. Furthermore, the image acquisition device 14 is not required to be limited to imaging the posterior segment of the eye 30 and can alternatively or additionally be arranged to acquire OCT images or other types of images (e.g., reflective images) of the anterior segment of the eye 30.

[0044] As in this example embodiment, the image acquisition device 14 may be a wide-field (WF) image acquisition device operable to acquire a WF image of the fundus of the eye 30. The fundus WF image is defined as a single-capture image centered on the fovea of ​​the eye 30, capturing retinal anatomy in the mid-periphery behind the vortex vein ampulla in all four quadrants of the eye 30 (i.e., the superior, inferior, nasal, and temporal quadrants). Therefore, the WF image acquisition device can acquire a single-capture image covering the retinal region extending from the fovea to the posterior margin of the vortex vein ampulla, and is defined as having a field of view (FoV) between 60 and 100 degrees. Here, FoV is expressed in terms of the eye angle, which is the angle subtended by the imaged retinal region at the center of the eye 30 (i.e., the intersection of the vertical diameter of the eyeball and the visual axis).

[0045] Image acquisition device 14 may alternatively be provided as an ultra-wide field (UWF) image acquisition device, which has a larger FoV than a WF device and is operable to acquire UWF images of the fundus covering a larger portion of the fundus. A UWF image of the fundus is defined as a single-shot image centered on the fovea of ​​the eye 30, capturing retinal anatomy in all four quadrants, in the far periphery, anterior to the ampulla of the vortex veins. Therefore, a UWF image acquisition device can acquire UWF images that are single-shot images covering a retinal region extending from the fovea to the anterior margin of the ampulla of the vortex veins and beyond the pars plana, and are defined as having an FoV (in eye angles) between 110 and 220 degrees. For example, the Optos Dayton™ is capable of capturing UWF images (so-called Optomap™ images) in a single shot that cover up to 200 degrees of the fundus (or approximately 82% of the retina).

[0046] It should be noted that the techniques described herein are not limited to their applicability to WF and UWF image acquisition devices, but are also applicable to ophthalmic image acquisition devices with a smaller FoV.

[0047] As in this example embodiment, the image acquisition device 14 may include an objective lens 15 that can move along a movement axis 16 toward and away from the eye 30 when the face 34 of the subject 32 is engaged with the patient interface 12. In this case, the patient interface 12 may be arranged to fix the orientation of the head 36 relative to the movement axis 16, such that the objective lens 15 can move along the movement axis 16 from a retracted position to an imaging position suitable for acquiring an image of the eye 30, while maintaining a distance from the nose 38 and eyebrows of the subject 32 greater than a predetermined distance to provide sufficient clearance between the objective lens 15 and the subject's face 34. The retracted position may be a position where the objective lens 15 is retracted away from the patient interface 12 along the movement axis 16, such that when the subject 32 is engaged with the patient interface 12, the objective lens 15 is further away from the subject 32 in the retracted position than in the imaging position. Configuring the patient interface 12 to orient the head 36 in this manner is particularly advantageous for the WF and UWF implementation of the image acquisition device 14, whose objectives 15 typically need to be moved close to the eyes 30 to achieve WF / UWF imaging. Therefore, unless the head 36 is properly oriented relative to the axis of movement 16, the objectives 15 are prone to contact with facial features such as the nose 38 or eyebrows of the subject 32. Contact between the objectives 15 and the subject 32 may cause the subject 32 to move and potentially detach from the patient interface 12, thus requiring repeated patient alignment procedures.

[0048] As in this example embodiment, the ophthalmic imaging instrument 10 may further include a stereo camera ranging system for measuring the distance between the objective lens 15 and the eye 30. This stereo camera ranging system includes a first camera 19a and a second camera 19b, which are arranged to image the eye 30 from different positions relative to the objective lens 15 (e.g., on opposite sides of the objective lens 15). For example, the first camera 19a and the second camera 19b may image an anterior region of the eye 30, such as the pupil of the eye 30. In this case, the patient interface 12 is preferably arranged to fix the orientation of the head 36 relative to the ophthalmic imaging instrument 10 to satisfy the further requirement that each of the first camera 19a and the second camera 19b has a corresponding field of view of the eye 30 that is not obstructed by obstacles such as facial features of the subject 32 (e.g., nose or eyebrows) or by the patient interface 12 itself, particularly when the objective lens 15 is located at or near a position where the image acquisition device 14 can acquire a WF image of the subject's retina. Taking this additional constraint into account when setting the orientation of the patient interface 12 relative to the rest of the ophthalmic imaging instrument 10 can help reduce the average duration of imaging sessions and thus increase patient throughput by reducing the occurrence of failures in the stereo camera ranging system caused by the subject 32’s nose or eyebrows obscuring the eyes 30 in one or two stereo images acquired by the stereo camera ranging system.

[0049] A stereo ranging system can be configured to monitor images captured by a first camera 19a and a second camera 19b to detect obstacles obstructing the field of view of eye 30 (such as the field of view of the pupil of eye 30). For example, when objective lens 15 is actuated from a retracted position to an imaging position, one or more anatomical features of the subject's face 34 (such as a nose or eyebrows) may at least partially obstruct the field of view of the first camera 19a and / or the second camera 19b. The stereo ranging system can be configured to monitor images captured by the stereo ranging system to detect obstacles, and if an obstacle is detected in the image, the stereo ranging system can be configured to perform one or more of the following: stop the movement of objective lens 15, generate an alarm to a clinician that cameras 19a, 19b have been obstructed, or retract objective lens 15 until the obstacle is removed.

[0050] As in this example embodiment, the ophthalmic imaging instrument 10 may further include: a base 17 on which the image acquisition device 14 is slidably mounted for movement along a movement axis 16; and a frame 18 extending from the base 17 and supporting the patient interface 12. The image acquisition device 14 is movable relative to the base 17 such that when the face 34 of the subject 32 engages with the patient interface 12, the objective lens 15 can move along the movement axis 16 toward and away from the eye 30. The image acquisition device 14 may also be movable relative to the base 17 in a lateral direction relative to the movement axis 16. This configuration advantageously allows any moving parts of the image acquisition device 14 (e.g., a cooling fan provided to cool the electrical components of the image acquisition device 14) to be enclosed in a housing separate from the frame 18 and the patient interface 12 supported therefrom. This makes it easier to protect the eye 30 (e.g., by using the housing and any seals between the housing and any parts of the housing that come into contact with the eye 30) from airflow generated within the image acquisition device 14, thereby preventing these airflows from reaching the eye 30 during imaging and thus irritating or drying it. Supporting the patient interface 12 from the frame 18 such that the face 34 is separated from the image acquisition device 14 when the subject's face 34 is engaged with the patient interface 12 provides the additional advantage of allowing clinicians easier access to the face 34 to perform eyelid lifting, presentation of handheld fixation targets, etc., during imaging.

[0051] As in this example embodiment, the patient interface 12 can be switched between a first configuration and a second configuration. The first configuration fixes the orientation of the head 36 relative to the ophthalmic imaging instrument 10 in a first relative orientation suitable for imaging the right eye of the subject 32 by the ophthalmic imaging instrument 10. The second configuration fixes the orientation of the head 36 relative to the ophthalmic imaging instrument 10 in a second relative orientation suitable for imaging the left eye of the subject 32 by the ophthalmic imaging instrument 10, wherein the second relative orientation differs from the first relative orientation. This ability to switch the configuration of the patient interface 12 in this way, for example by moving the patient interface 12 between a first rest position and a second rest position, allows the orientation of the head 36 to be optimal so that the ophthalmic imaging instrument 10 can image each eye of the subject 32.

[0052] A first relative orientation of the head 36 suitable for imaging the right eye of the subject 32 can be an orientation in which the subject's head 36 is rotated counterclockwise from a forward-facing orientation, such that the head 36 is oriented to the left of the axis of motion 16 of the objective lens 15 (from the subject 32's perspective). Rotating the subject's head 36 counterclockwise has the effect of moving the subject's nose and eyebrows away from the axis of motion 16 of the objective lens 15, thereby allowing the objective lens 15 to be positioned close to the imaging position of the subject's eye 30 without being obstructed by the nose and / or eyebrows of the head 36. When the head 36 is fixed in the first orientation via the patient interface 12, the head 36 can be oriented at an angle between approximately 10 degrees and 40 degrees relative to the axis of motion 16 of the objective lens 15.

[0053] A second relative orientation of the head 36 suitable for imaging the left eye of the subject 32 can be an orientation in which the subject's head 36 is rotated clockwise from a forward-facing orientation, such that the head 36 is oriented to the right of the axis of movement 16 of the objective lens 15 (from the subject 32's perspective). Rotating the subject's head clockwise has the effect of moving the subject's nose and eyebrows away from the optical axis of the objective lens, thereby allowing the objective lens 15 to be positioned at a working distance from the subject's eye 30 without being obstructed by the nose and / or eyebrows of the head 36. When the head 36 is fixed in the second orientation via the patient interface 12, the head 36 can be oriented at an angle between approximately 10 degrees and 40 degrees relative to the axis of movement 16 of the objective lens 15.

[0054] Furthermore, rotating the subject's nose and eyebrows away from the objective lens 15 allows the subject's head 36 to be oriented relative to the ophthalmic imaging instrument 10 such that each of the first camera 19a and the second camera 19b has a corresponding field of view of the eyes 30 that is not obstructed by the subject's facial features (e.g., nose or eyebrows).

[0055] When the ophthalmic imaging instrument 10 includes the base 17 and the frame 18 as described above, the frame 18 can be as follows: Figure 4 The diagram shows an arcuate guide rail 18a, and the patient interface 12 is slidably mounted on the arcuate guide rail 18a via its component 12a, which is arranged to engage the arcuate guide rail 18a and slide along the arcuate guide rail 18a (e.g., Figure 5 As shown), so as to be movable between (i) a first position on guide rail 18a and (ii) a second position on guide rail 18a: in the first position, the patient interface 12 is arranged to fix the orientation of the head 36 relative to the ophthalmic imaging instrument 10 in a first relative orientation to image the right eye of the subject; the second position differs from the first position in that the patient interface 12 is arranged to fix the orientation of the head 36 relative to the ophthalmic imaging instrument 10 in a second relative orientation to image the left eye of the subject. In this case, the ophthalmic imaging instrument 10 may also include a drive mechanism arranged to move the patient interface 12 between the first position on the arcuate guide rail 18a and the second position on the arcuate guide rail 18a. For example, the drive mechanism may have a Bowden cable 18b, and the Bowden cable 18b may be arranged to push or pull the patient interface 12 between the first position on the arcuate guide rail 18a and the second position on the arcuate guide rail 18a. Alternatively, the patient interface 12 may be moved manually between the first position and the second position.

[0056] Figure 4 This is an end view of the ophthalmic imaging instrument 10 taken from the perspective of subject 32, wherein the patient interface 12 is in a first configuration or first position. (As shown) Figure 4 As shown, when the patient interface 12 is in the first position, the patient interface 12 moves along the rack 18 to the first position. In the example shown, the first position is when the patient interface 12 moves along the rack 18 from a straight position (e.g., ...). Figure 2 (As shown) Moved to the left-hand position. When the patient interface 12 is moved to this left-hand position, it is positioned such that when the subject 32 engages with the patient interface 12, the subject's head 36 is in a first relative orientation suitable for imaging the subject's right eye. When the subject's head 36 is in the first relative orientation, the orientation of the patient interface 12 in the first position relative to the ophthalmic imaging device 10 can be the same as the orientation of the head 36.

[0057] Figure 5 This is an end view of the ophthalmic imaging instrument 10 taken from the perspective of subject 32, wherein the patient interface 12 is in a second configuration or second position. (As shown) Figure 5 As shown, when the patient interface 12 is in the second position, the patient interface 12 moves along the rack 18 from a straight position (e.g., Figure 2(As shown) Move to the second position. In the example shown, the second position is the position where the patient interface 12 moves along the rack 18 to the right-hand position. When the patient interface 12 moves to the right-hand position, it is positioned such that when the subject 32 engages with the patient interface 12, the subject's head 36 is in a second relative orientation suitable for imaging the subject's left eye. When the subject's head 36 is in the second relative orientation, the orientation of the patient interface 12 relative to the ophthalmic imaging device 10 in the second position can be the same as the orientation of the head 36.

[0058] Using the curved guide rail 18a in this way provides a simple and reliable mechanism for switching the configuration of the patient interface 12 between a first and a second configuration, with a relatively low number of parts. Furthermore, by appropriately setting the curvature of the guide rail 18a so that it presents a concave section from the perspective of the subject 32, when the patient interface 12 is in the first and second positions on the guide rail 18a, respectively, the right and left eyes of the subject 32 can be presented to the image acquisition device 14 at similar positions relative to the image acquisition device 14. For example, the curvature of the guide rail 18a can follow an arcuate path, approximately centered on a point corresponding to the rotation axis of the subject's head 36. In other words, the arcuate path followed by the patient interface 12 as it moves between the first and second positions is approximately the same path that the subject's face 34 will follow if the subject 32 is to remain engaged with the patient interface 12 when the patient interface 12 moves between the first and second positions. Therefore, relatively small horizontal movements of the objective lens 15 may be required to align it laterally with each eye, allowing for relatively quick sequential examination of both eyes of the subject. Another benefit is that the subject 32 can naturally and easily rotate their head 36 after one eye has been imaged by the ophthalmic imaging instrument 10 to change the orientation of the head 36 from a first orientation to a second orientation for imaging the other eye. Therefore, relatively small adjustments to the subject's body may be required for imaging both eyes, which can reduce the duration of the imaging session.

[0059] However, it should be noted that, in addition to using the curved guide rail 18a, the patient interface 12 can switch between the first and second configurations, for example, by employing a relatively complex arrangement of linkages, which substantially reproduces the movement of the patient interface 12 as described above when it slides between the first and second positions. Alternatively, when the subject's face 34 is engaged with the patient interface 12, the patient interface 12 can be switched between the first and second configurations by simply pivoting around a point near the subject's forehead. However, in this case, switching the patient interface 12 between the first and second configurations would require the subject 32 to laterally move their head 36 (and rotate their head 36), and a corresponding lateral movement of the objective lens 15.

[0060] As in this example embodiment, the patient interface 12 can operate in a third configuration to fix the orientation of the head 36 relative to the ophthalmic imaging instrument 10 in a third relative orientation adapted for the ophthalmic imaging instrument 10 to image the right and left eyes of the subject 32. The third configuration can be as follows: Figure 2 The vertical position shown. In the third configuration, the patient interface can fix the orientation of the head 36 relative to the ophthalmic imaging instrument 10, such that the head 36 is oriented in a manner that aligns it with the axis of movement 16 of the objective lens 15, as shown. Figure 2 As shown. When the patient interface 12 fixes the orientation of the head 36 in the third position, the user looks directly at the objective lens 15. The objective lens 15 can be laterally actuated, allowing it to move between the left-eye imaging position and the right-eye imaging position without changing the orientation of the head 36.

[0061] In some example embodiments, the ophthalmic imaging instrument 10 may include a patient interface 12 fixed in a third configuration or upright position, such that the orientation of the user's head 36 is fixed in the third relative orientation as described above. Furthermore, in some example embodiments, the ophthalmic imaging instrument 10 may include a patient interface 12 movable between a first configuration and a second configuration, or between a first configuration, a second configuration, and a third configuration.

[0062] Regarding the form of the patient interface 12, it differs from conventional patient interfaces in several important respects. Conventional patient interfaces typically include a forehead rest and a chin rest to help stabilize the subject's head 36 during imaging, while allowing the head 36 to rotate about these pivot points and leaving the subject 32 to minimize such rotation. However, the patient interface 12 of this example embodiment is arranged to suppress this degree of freedom in head movement and thus fix the orientation of the subject's head 36 relative to the ophthalmic imaging instrument 10. When the subject 32's face 34 engages with the patient interface 12, the patient interface 12 achieves this by contacting not only the first portion 34-1 (also referred to as the upper portion) of the face 34 covering the frontal bone of the head 36 (thus, for example, contacting the subject's forehead), but also the corresponding second portion 34-2 (also referred to as the left and right portions) of the face 34 covering each zygomatic bone (i.e., the cheek bone) of the head 36. Thus, the patient interface 12 can securely contact the subject's head 36 at three different contact areas (or anchor points) because the soft tissue covering the frontal and zygomatic bones is relatively thin. Furthermore, these contact areas are widely spaced, thus providing excellent stability for the head 36 during imaging by the eye 30. The patient interface 12 also provides support for the subject's face 34, allowing the subject 32 to comfortably remain engaged with the patient interface 12 without the need for an additional chin rest to support the subject's head 36.

[0063] The patient interface 12 is shaped to conform to the face 34, having a generally concave shape to accommodate the face 34. As in this example embodiment, the patient interface 12 may be shaped to avoid contact with the nose 38 of the subject 32 and the third portion 34-3 (also referred to as the lower portion) of the face 34 covering the maxilla of the head 36 when the subject 32 engages with the patient interface 12. Thus, the patient interface 12 may be arranged to avoid contact with the nose 38 of the subject 32 and the surrounding portions of the face 34, which are located between opposing second portions 34-2 and below the subject's eyes.

[0064] like Figure 8As shown, when viewed from the end where the subject 32 is positioned during imaging, the patient interface 12 is generally C-shaped, and in this view, the patient interface 12 has a central (optionally straight) elongated portion 104. The central elongated portion 104 includes a central contact portion 101 that engages with a first portion 34-1 of the face 34 when the subject 32 is engaged with the patient interface 12. Corresponding arched portions 105, 106 extend downward and proximally from opposite ends of the central elongated portion 104. Each arched portion 105, 106 extends only downward along an arched path and proximally from opposite ends of the central elongated portion 104, the dimensions of which are designed to surround the eye socket of the subject 32 when the subject 32 is engaged with the patient interface 12. A gap extends between the ends of each arched portion 105, 106 such that when the subject 32 is engaged with the patient interface 12, the subject's nose 38 can be accommodated within the gap without being contacted by the patient interface 12.

[0065] Each arched portion 105, 106 includes a corresponding left contact portion 102 and a right contact portion 103, wherein each contact portion is configured to contact a corresponding second portion of the second portions 34-2 of the face 34. The corresponding left contact portion 102 and right contact portion 103 of the patient interface 12 are located on the corresponding arched portions 105, 106 such that when the subject 32 engages with the patient interface 12, the contact portions 102, 103 contact the corresponding left and right cheekbones of the subject. The left contact portion 102 may be located at the end of the arched portion 105 remote from the central portion 101, and the right contact portion 103 of the contact surface may be located at the end of the arched portion 106 remote from the central portion 101. Therefore, the patient interface 12 can have a compact construction for securely fixing the orientation of the subject's head 36. The left contact portion 102 and the right contact portion 103 are located at a common height on the corresponding elongated arched portions 105 and 106 of the patient interface 12, which is below the height of the central contact portion 101. Thus, the left contact portion 102, the right contact portion 103, and the central portion 101 are distributed in a pyramidal shape on the patient interface 12, providing three contact points or anchor points for the subject's face 34 to engage with the patient interface 12. These contact points or anchor points are spaced apart to securely fix the orientation of the subject's head 36 when the subject 32 engages with the patient interface 12.

[0066] When the subject 32 is engaged with the patient interface 12, when viewed from the left or right side of the subject's head 36, the arched portions 105, 106 of the patient interface 12 curve around the subject 32's eye 30 (however, not necessarily centered on the eye), and this curve can... Figure 9 and Figure 10As seen in the image, when the subject 32 engages with the patient interface 12, when viewed from above the subject's head 36, the arched portions 105, 106 of the patient interface 12 extend proximally, such that each arched portion 105, 106 bends around the side of the subject's face 34, and this bend can... Figure 10 I saw it in the middle.

[0067] like Figure 10 As best shown, the central elongated portion 104 of the central contact portion 101 of the patient interface 12 may be concave, such that the central contact portion 101 conforms to the shape of the upper portion 34-1 of the subject's face 34. Arched portions 105, 106 extend from opposite ends of the central portion 101 in a proximal direction (when viewed from above), such that each of the left contact portion 105 and the right contact portion 106 is located proximal to the central contact portion 101. The patient interface 12 may include a continuous surface extending between each of the left contact portion 102 and the right contact portion 103, wherein the central contact portion 101 is disposed between this continuous surface. A subject with a relatively small head may contact the patient interface 12 only at the upper contact portion 101 and the corresponding left contact portion 102 and right contact portion 103. Subjects with larger heads will also contact the patient interface 12 at the upper contact portion 101 and the corresponding left contact portion 102 and right contact portion 103, but they may also contact at least some additional portions of the surface extending between the various contact portions 101, 102, 103. Advantageously, this allows subjects with various head shapes and sizes to use the patient interface 12 and comfortably fix their heads in an orientation suitable for imaging.

[0068] The patient interface 12, with its generally concave shape including the central portion 104 and elongated arched portions 105, 106, allows it to securely hold heads with various facial shapes in place, as the position of the cheekbones on the face varies very little. Furthermore, shaping the patient interface 12 as described above to avoid contact with the nose 38 of the subject's face 34 and the surrounding portion located between the opposing second portions 34-2 and below the subject's eyes allows clinicians to approach the subject's eyes 30 to lift the eyelids for imaging, or to insert and move a handheld fixation target in front of one of the subject's eyes to change and fix the gaze direction of the observing eye, thereby also changing and fixing the gaze direction of the other eye imaged by the image acquisition device 14. Additionally, this shape of the patient interface 12 improves its compatibility with a wider range of facial shapes and specifically prevents the usability of the patient interface 12 from being impaired by variations in the shape and / or size of the nose.

[0069] The patient interface 12 can be manufactured and sold as a separate component and can be attached to ophthalmic imaging instruments via a rack (as described above) or in another manner. The patient interface 12 of this example embodiment is... Figures 6 to 8 As shown, the interface 12 has a continuous, elongated contact surface, including a central portion 101 arranged to contact a first portion 34-1 of the face 34 when the subject's face 34 engages with the patient interface 12. The contact surface extends continuously to each end portion 102 and 103, each end portion 102 and 103 arranged to contact a corresponding second portion 34-2 of the face 34 when the subject's face 34 engages with the patient interface 12. Providing such a continuous, elongated contact surface makes it easier to wipe the patient-facing portion of the patient interface 12 clean between examinations of different subjects and makes sterilization of that portion more effective. The continuity of the contact surface provides the additional benefit of increasing the contact area between the patient interface 12 and the subject's face 34, thereby helping to keep the subject's head 36 stable during imaging and making the subject 32 more comfortable by reducing contact pressure, thus making the subject 32 less likely to move during imaging to alleviate discomfort.

[0070] As in this example embodiment, the patient interface 12 may include at least one compressible contact member 12b, wherein contact surfaces are disposed on the compressible contact member 12b to contact a first portion 34-1 and each second portion 34-2 of the face 34 when the face 34 engages with the patient interface 12. The compressible contact member 12b may be made of, for example, medical-grade silicone and may be compressible enough to allow the patient interface 12 to accommodate different head sizes, but low enough to make the head 36 sufficiently stable relative to the ophthalmic imaging instrument 10 to reduce or avoid motion-related image artifacts, regardless of head size. Therefore, providing such a compressible contact member 12b to the patient interface 12 can improve the versatility of the patient interface 12. However, even if the patient interface 12 is rigid and does not have a compressible contact member 12b, the patient interface 12 can still be shaped to accommodate a fairly wide range of adult head sizes. In addition, in some example embodiments, different sized versions of the patient interface 14 (with or without the compressible contact member 12b) may be provided, which may be interchangeably attached to the ophthalmic imaging instrument 10 to allow it to accommodate a wider range of head sizes than it could otherwise accommodate (e.g., to young children), thereby providing good head stability, but in some cases at the expense of patient throughput.

[0071] As an additional or alternative method to improve the image quality of the acquired ocular images by reducing discomfort during imaging by making the patient more comfortable and therefore less prone to movement, the patient interface 12 may (e.g., relative to the rest of the ophthalmic imaging instrument 10) be positioned and oriented such that when the subject 32 tilts forward from an upright sitting position (i.e., leans forward) to engage with the patient interface 12, the subject 32's head 36 has a downward tilt that is greater than the tilt of the head 36 when the subject 32 is in an upright sitting position, for example, 10 to 20 degrees greater (preferably 13 to 17 degrees greater, and more preferably 15 degrees greater). This allows the subject 32 to adopt a more natural posture when engaging with the patient interface 12 than it would adopt when engaging with a patient interface 12 that does not have the described position and orientation.

[0072] Now go to Figure 11 A flowchart is shown that outlines a method for imaging the eyes of a subject 32 using the ophthalmic imaging instrument 10 while the subject's head 36 is oriented relative to the ophthalmic imaging instrument 10 using the patient interface 12. In step 901, the subject's face 34 engages with the patient interface 12. Engaging the patient interface 12 with the subject's face 34 may include bringing the subject's face 34 into contact with the patient interface 12. For example, the subject 32 may move from an upright sitting position toward the patient interface 12, wherein the subject tilts toward the patient interface to bring the subject's face 34 into contact with the patient interface 12.

[0073] Once the subject's face 34 is engaged with the patient interface 12, the patient interface 12 fixes the orientation of the subject's head 36 relative to the ophthalmic imaging instrument 10 in step 902. When the subject's face 34 is engaged with the patient interface 12, the patient interface 12 can fix the subject's head 36 in orientation relative to the ophthalmic imaging instrument 10 by contacting the first portion or upper portion 34-1 of the face 34 covering the frontal bone of the head 36 and the corresponding second portion or left and right portions 34-2 of the face 34 covering each cheekbone of the head 36. Contacting the frontal bone and each cheekbone of the face 34 with the patient interface 12 has the effect of anchoring the subject's head 36 relative to the ophthalmic imaging instrument 10, such that the subject 32 cannot change the orientation of his / her head 36 unless he / she first disengages one or more of the upper, left, and right portions of the subject's face 34 from the patient interface 12.

[0074] In an embodiment where the ophthalmic imaging instrument 10 includes a movable objective lens 15, the method may include step 903, in which the objective lens 15 is moved along a movement axis 16 from a retracted position to an imaging position. Moving the objective lens 15 from the retracted position to the imaging position may include moving the objective lens 15 along the movement axis 16 while the subject's head 36 is fixed in an orientation relative to the ophthalmic imaging instrument 10 via the patient interface 12. Moving the objective lens 15 may include moving the image acquisition device 14.

[0075] In step 904, an image of the subject's eye is acquired by the ophthalmic imaging instrument 10 while the subject's face 34 is engaged with the patient interface 12 and thus the orientation of the subject's head 36 is fixed relative to the ophthalmic imaging instrument 10.

[0076] Figure 12 This is a flowchart outlining a method for imaging the eyes of a subject 32 using the ophthalmic imaging instrument 10 while fixing the subject's head 36 relative to the orientation of the ophthalmic imaging instrument 10 using the patient interface 12. In step 1001, the patient interface 12 is positioned in a first orientation relative to the ophthalmic imaging instrument 10. For example, the patient interface 12 may be positioned in a first position (left position) suitable for imaging the right eye of the subject 32. In step 1002, when the patient interface 12 is in the first position, as described above regarding... Figure 11 As described in step 901, subject 32 engages patient interface 12 with his / her face 34.

[0077] Once the subject's face 34 engages with the patient interface 12, in step 1003, the orientation of the subject's head 36 is fixed in a first orientation relative to the ophthalmic imaging instrument 10. In this example, when the first position of the patient interface 12 is suitable for imaging the right eye of the subject 32, the subject's head 36 is fixed in an orientation in which the subject's head 36 faces to the left of the movement axis 16 of the objective lens 15 (from the subject's perspective). In step 1004, an image of the subject 32's first eye is acquired while the orientation of the subject's head 36 is fixed. In some embodiments, the objective lens 15 can be moved from a retracted position to an imaging position before acquiring the image of the first eye. Furthermore, after acquiring the image of the first eye, the objective lens 15 can be moved from the imaging position to the retracted position.

[0078] After acquiring an image of the subject's first eye, the subject 32 can detach from the patient interface 12, and the patient interface 12 can be moved from a first position to a second position in step 1005. Moving the patient interface 12 from the first position to the second position may include sliding the patient interface 12 along an arcuate path such that when the patient interface 12 is in the first position, the patient interface 12 is oriented at a first angle relative to the axis of movement 16 of the objective lens 15, and when the patient interface 12 is in the second position, the patient interface 12 is oriented at a second angle relative to the axis of movement 16 of the objective lens 15, wherein the first angle is different from the second angle.

[0079] In step 1006, with the patient interface 12 in the second position, the subject 32 engages the patient interface 12 with the subject's face 34. In step 1007, the subject's head 32 is secured via the patient interface 12 in a second orientation relative to the ophthalmic imaging instrument 10. The second orientation of the subject's head 36 may be a position suitable for imaging the left eye of the subject 32, and the subject's head 36 may be secured in an orientation in which the subject's head 36 faces the right side of the movement axis 16 of the ophthalmic imaging instrument 10 (from the subject's perspective). In step 1008, an image of the subject 32's second eye is acquired while the orientation of the subject's head 36 is secured in the second orientation. Before acquiring the image of the second eye, the objective lens of the ophthalmic imaging instrument 10 may be moved to an imaging position for imaging the second eye. For example, the objective lens 15 may be actuated from a retracted position to an imaging position.

[0080] Moving the objective lens 15 between the retracted position and the imaging position may include acquiring an image of the anterior region of the eye before and during the movement of the objective lens 15. For example, a stereo ranging system (as described above) for measuring the distance between the objective lens 15 and the eye can be used to image the anterior region of the eye and determine the distance between the objective lens and the anterior region of the eye. Moving the objective lens 15 from the retracted position to the imaging position can be based on the determined distance between the objective lens 15 and the eye.

[0081] Furthermore, images acquired by the stereo ranging system can be monitored to detect obstacles obstructing the field of view of the anterior region of the eye. For example, when objective lens 15 is actuated from a retracted position to an imaging position, one or more anatomical features of the subject's face 34 (e.g., nose or eyebrows) may at least partially obstruct the field of view of one or more cameras in the stereo ranging system. The method may include monitoring images captured by the stereo ranging system to detect obstacles. If an obstacle is detected in the image, the method may include one or more of the following: stopping the movement of the objective lens, generating an alert to a clinician that a camera has been obstructed, and retracting objective lens 15 until the obstacle is removed. If an obstacle is detected, the subject may disengage from patient interface 12, allowing the orientation of patient interface 12 relative to ophthalmic imaging system 10 to be changed. Changing the orientation of patient interface 12 advantageously allows the angle of the subject's head 36 to change relative to objective lens 15, enabling control over the position of the subject's facial anatomical features to prevent obstruction of images captured by the stereo ranging system.

[0082] Additionally or alternatively, the method may include monitoring the distance between the objective lens 15 and the face 34 of the subject 32 as the objective lens 15 is moved from the retracted position to the imaging position, and stopping the movement of the objective lens 15 from the retracted position to the imaging position if a collision is predicted. Predicting when a collision is likely to occur may include measuring the distance between the objective lens 15 and the subject's face 34. This can be performed, for example, by a proximity sensor mounted on the objective lens or by a stereo ranging system.

[0083] In the foregoing description, exemplary aspects have been described with reference to several exemplary embodiments. Therefore, the specification should be considered illustrative rather than restrictive. Similarly, the accompanying drawings, which highlight the functionality and advantages of exemplary embodiments, are presented merely for illustrative purposes. The architecture of the exemplary embodiments is flexible and configurable enough that it can be utilized in ways other than those shown in the drawings.

[0084] While various exemplary embodiments of the invention have been described above, it should be understood that they are presented by way of example and not limitation. It will be apparent to those skilled in the art that various changes in form and detail may be made. Therefore, the invention should not be limited to any of the exemplary embodiments described above, but should be defined solely by the appended claims and their equivalents. It should be understood that any process recited in the claims need not be performed in the order presented.

[0085] While this specification contains numerous details of specific embodiments, these should not be construed as limiting the scope of any invention or potentially claimed content, but rather as descriptions of features specific to the particular embodiments described herein. Certain features described in this specification within the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, although features may be described above as acting in a particular combination and even initially claimed in this way, one or more features from a claimed combination may be removed from the combination in some cases, and the claimed combination may be for a sub-combination or a variation thereof.

Claims

1. An ophthalmic imaging instrument (10) for imaging the eye (30) of a subject (32), comprising: The patient interface (12) is used to engage the face (34) of the head (36) of the subject (32) during imaging of the eye (30). The patient interface (12) is arranged to fix the orientation of the head (36) relative to the ophthalmic imaging instrument (10) by contacting the upper part (34-1) of the face (34) covering the frontal bone of the head (36) and the corresponding left and right portions (34-2) of the face (34) covering each cheekbone of the head (36) when the face (34) of the subject (32) engages with the patient interface (12). and An image acquisition device (14) is arranged to acquire an image of the eyes (30) when the face (34) of the subject (32) is engaged with the patient interface (12).

2. The ophthalmic imaging instrument (10) according to claim 1, wherein, The patient interface (12) is arranged to avoid contact with the nose (38) of the subject (32) and the lower part (34-3) of the face (34) covering the maxilla of the head (36) when the face (34) of the subject (32) engages with the patient interface (12).

3. The ophthalmic imaging instrument (10) according to claim 2, wherein, The patient interface (12) has an elongated contact surface including a central portion (101) arranged to contact a first portion (34-1) of the face (34) of the subject (32) when the face (34) of the subject (32) engages with the patient interface (12). The contact surface extends to each of a first end portion (102) and a second end portion (103) of the contact surface, the first end portion (102) and the second end portion (103) being arranged to contact a left and right portion (34-2) of the face (34) of the subject (32) when the face (34) of the subject (32) engages with the patient interface (12).

4. The ophthalmic imaging instrument (10) according to claim 3, wherein, The elongated contact surface also includes a first arched portion (105) and a second arched portion (106) extending from opposite ends of the central portion (101), each of the first arched portion (105) and the second arched portion (106) extending along a corresponding arched path from a corresponding end of the central portion (101) to a corresponding one of the first end portion (102) and the second end portion (103), the corresponding arched path being sized to surround the eye socket of the subject (32) when the face (34) of the subject (32) engages with the patient interface (12).

5. The ophthalmic imaging instrument (10) according to claim 4, wherein, The first end portion (102) of the contact surface is disposed at the end of the first arcuate portion (105) away from the center portion (101), and the second end portion (103) of the contact surface is disposed at the end of the second arcuate portion (106) away from the center portion (101).

6. The ophthalmic imaging instrument (10) according to claim 4 or claim 5, wherein, The first bow-shaped portion (105) and the second bow-shaped portion (106) are arranged such that a gap is provided between the first end portion (102) and the second end portion (103), and wherein, when the face (34) of the subject (32) engages with the patient interface (12), the nose (38) of the subject (32) can be accommodated within the gap without being contacted by the patient interface (12).

7. The ophthalmic imaging instrument (10) according to any of the preceding claims, wherein, The patient interface (12) is oriented such that when the subject (32) tilts forward from an upright sitting position to engage with the patient interface (12), the subject's head (36) has a downward tilt that is greater than the tilt when in the upright sitting position.

8. The ophthalmic imaging instrument (10) according to any of the preceding claims, wherein, The image acquisition device (14) includes an objective lens (15) that is movable along a movement axis (16) toward and away from the eye (30) when the face (34) of the subject (32) is engaged with the patient interface (12), and The patient interface (12) is arranged to fix the orientation of the head (36) relative to the axis of movement (16) such that the objective lens (15) can be moved along the axis of movement (16) to a position for acquiring the image of the eye (30).

9. The ophthalmic imaging instrument (10) according to claim 8 further comprises: The image acquisition device (14) is slidably mounted on the base (17). and A rack (18) extends from the base (17) and supports the patient interface (12). The image acquisition device (14) is slidable relative to the base (17) such that when the face (34) of the subject (32) is engaged with the patient interface (12), the objective lens (15) is able to move toward and away from the eye (30) along the axis of movement (16).

10. The ophthalmic imaging instrument (10) according to claim 8 or claim 9, further comprising a stereo camera ranging system for measuring the distance between the objective lens (15) and the eye (30) when the subject's face is engaged with the patient interface, the stereo camera ranging system comprising a first camera (19a) and a second camera (19b), the first camera (19a) and the second camera (19b) being arranged to image the eye (30) from different positions relative to the objective lens (15), wherein, The patient interface (12) is arranged to fix the orientation of the head (36) relative to the ophthalmic imaging instrument (10) such that each of the first camera (19a) and the second camera (19b) has a corresponding field of view of the eyes (30) that is not obscured by the facial features of the subject (32).

11. The ophthalmic imaging instrument (10) according to any of the preceding claims, wherein, The patient interface (12) is operable to fix the orientation of the head (36) relative to the ophthalmic imaging instrument (10) at: First relative orientation for imaging the right eye of the subject (32) by the ophthalmic imaging instrument (10); and A second relative orientation is used for imaging the left eye of the subject (32) by the ophthalmic imaging instrument (10), the second relative orientation being different from the first relative orientation.

12. The ophthalmic imaging instrument (10) according to claim 11 when dependent on claim 9, wherein, The frame (18) includes an arcuate guide rail (18a), and the patient interface (12) is slidably mounted on the arcuate guide rail (18a) so as to be movable between the following positions: At the first position on the guide rail, the patient interface (12) is arranged to fix the orientation of the head (36) relative to the ophthalmic imaging instrument (10) on the first relative orientation to image the right eye of the subject (32). and At the second position on the guide rail, the patient interface (12) is arranged to fix the orientation of the head (36) relative to the ophthalmic imaging instrument (10) in the second relative orientation to image the left eye of the subject (32).

13. The ophthalmic imaging instrument of claim 12 further includes a drive mechanism having a Bowden cable (18b) arranged to move the patient interface (12) between a first position on the arcuate guide (18a) and a second position on the arcuate guide (18a).

14. The ophthalmic imaging instrument (10) according to any of the preceding claims, wherein, The patient interface (12) includes at least one compressible contact member (12b) arranged to contact the upper portion (34-1) of the face (34) and the corresponding left and right portions (34-2) of the face (34) when the face (34) of the subject (32) engages with the patient interface (12).

15. The ophthalmic imaging instrument (10) according to any of the preceding claims, wherein, The image acquisition device (14) is an optical coherence tomography (OCT) image acquisition device, which is arranged to acquire at least one of the following: an OCT image of the retina of the eye (30), an OCT angiography image of the retina, or an OCT image of the anterior segment of the eye (30).

16. A patient interface (12) capable of being attached to an ophthalmic imaging instrument (10), wherein, When the patient interface (12) is attached to the ophthalmic imaging instrument (10) and engages with the face (34) of the subject (32), it is arranged to fix the orientation of the head (36) relative to the ophthalmic imaging instrument (10) by contacting the upper part (34-1) of the face (34) covering the frontal bone of the head (36) of the subject (32) and the corresponding left and right portions (34-2) of the face (34) covering each cheekbone of the head (36), so that the ophthalmic imaging instrument (10) can acquire an image of the eye (30).

17. The patient interface (12) according to claim 16, wherein, The patient interface (12) is arranged to avoid contact with the nose (38) of the subject (32) and the lower part (34-3) of the face (34) covering the maxilla of the head (36) when the face (34) of the subject (32) engages with the patient interface (12).

18. The patient interface (12) according to claim 17, wherein, The patient interface (12) has an elongated contact surface including a central portion (101) arranged to contact the upper portion (34-1) of the face (34) of the subject (32) when the face (34) of the subject (32) engages with the patient interface (12). The contact surface extends to each of a first end portion (102) and a second end portion (103) of the contact surface, the first end portion (102) and the second end portion (103) being arranged to contact the left and right portions (34-2) of the face (34) of the subject (32) respectively when the face (34) of the subject (32) engages with the patient interface (12).

19. The patient interface (12) according to claim 18, wherein, The elongated contact surface also includes a first arched portion (105) and a second arched portion (106) extending from opposite ends of the central portion (101), each of the first arched portion (105) and the second arched portion (106) extending along a corresponding arched path from a corresponding end of the central portion (101) to a corresponding one of the first end portion (102) and the second end portion (103), the corresponding arched path being sized to surround the eye socket of the subject (32) when the face (34) of the subject (32) engages with the patient interface (12).

20. The patient interface (12) according to claim 19, wherein, The first end portion (102) of the contact surface is disposed at the end of the first arcuate portion (105) away from the center portion (101), and the second end portion (103) of the contact surface is disposed at the end of the second arcuate portion (106) away from the center portion (101).

21. The patient interface (12) according to claim 19 or claim 20, wherein, The first bow-shaped portion (105) and the second bow-shaped portion (106) are arranged such that a gap is provided between the first end portion (102) and the second end portion (103), and wherein, when the face (34) of the subject (32) engages with the patient interface (12), the nose (38) of the subject (32) can be accommodated within the gap without being contacted by the patient interface (12).

22. A method for imaging the eye (30) of a subject (32) using an ophthalmic imaging instrument (10), wherein, The ophthalmic imaging instrument (10) includes a patient interface (12) during imaging of the eyes (30) of a subject (32), wherein the face (34) of the subject's head (36) is engaged with the patient interface (12), the method comprising: The face (34) of the head (36) of the subject (32) is coupled to the patient interface (12); When the face (34) of the subject (32) engages with the patient interface (12), the head (36) is fixed in orientation relative to the ophthalmic imaging instrument (10) by contacting the upper part (34-1) of the face (34) covering the frontal bone of the subject's head (36) and the corresponding left and right portions (34-2) of the face (34) covering each cheekbone of the head (36); and An image of the eyes (30) is acquired when the face (34) of the subject's head (36) is engaged with the patient interface (12).

23. The method according to claim 22, wherein, The ophthalmic imaging instrument (10) includes an objective lens (15) that is movable toward and away from the eye (30) along a movement axis (16) when the face (34) of the subject (32) is engaged with the patient interface (12), wherein fixing the subject's head (36) includes fixing the orientation of the head (36) relative to the movement axis (16) and moving the objective lens (15) along the movement axis (16) to an imaging position for acquiring the image of the eye (30).

24. The method according to claim 23, wherein, The method further includes imaging both eyes (30) of the subject (32), wherein: Fixing the patient's head (36) in the orientation relative to the ophthalmic imaging instrument (10) includes: The head (36) is fixed in a first relative orientation so that the first eye (30) of the subject (32) can be imaged by the ophthalmic imaging instrument (10); and The head (36) is fixed in a second relative orientation so that the second eye (30) of the subject (32) can be imaged by the ophthalmic imaging instrument (10).

25. The method according to claim 24, wherein, Fixing the head (36) to the second relative orientation includes moving the patient interface (12) from the first position to the second position.

26. The method according to claim 25, wherein, Moving the patient interface (12) from the first position to the second position includes sliding the patient interface (12) along an arcuate path such that when the patient interface (12) is in the first position, the patient interface (12) is oriented at a first angle relative to the axis of movement (16) of the objective lens (15), and when the patient interface (12) is in the second position, the patient interface (12) is oriented at a second angle relative to the axis of movement of the objective lens (15), wherein the first angle is different from the second angle.

27. The method according to any one of claims 23 to 26, further comprising moving the objective lens (15) from the retracted position to the imaging position while the subject’s head (36) is fixed in the orientation relative to the ophthalmic imaging instrument (10).

28. The method according to claim 27, wherein, Moving the objective lens (15) from the retracted position to the imaging position includes: acquiring an image of the anterior region of the eye (30), determining the distance between the anterior region of the eye (30) and the ophthalmic imaging instrument (10) based on the acquired image, and moving the objective lens (15) to the imaging position based on the determined distance.

29. The method of claim 28, comprising using a camera (19a, 19b) to acquire an image of the anterior region of the eye (30) and monitoring the acquired image to detect anatomical features of the face (34) that obstruct the field of vision of the anterior region of the eye (30).

30. The method according to claim 29, wherein, The method includes changing the orientation of the patient interface (12) if there is an obstruction.

31. The method according to any one of claims 27 to 30, comprising monitoring the gap between the objective (15) and the face (34) of the subject (32) as the objective (15) is moved from the retracted position to the imaging position, and stopping the movement of the objective (15) from the retracted position to the imaging position if a collision is predicted.

Images