Gaze fixation system for ophthalmic imaging instrument

Abstract

The invention relates to a gaze fixation system for an ophthalmic imaging instrument. The ultra-wide field ophthalmic imaging instrument includes: a rotatable mirror that scans with a light beam on a fundus of an eye via a focal point of an ellipsoidal mirror to acquire an ultra-wide field image of the fundus of the eye, a pupil of the eye being at another focal point of the ellipsoidal mirror; and a light source that projects fixation light for fixing the gaze of the eyes. The instrument also has a processor that controls the rotatable mirror to be stationary in a predetermined orientation and controls the light source to project fixation light onto the fundus via the rotatable mirror and the ellipsoidal mirror to fix a gaze direction of the eye. The processor then controls the ultra-wide field ophthalmic imaging instrument to acquire an ultra-wide field image of the fundus by controlling the rotatable mirror to scan with the light beam on the fundus via the ellipsoidal mirror.

Description

field

[0001] The examples in this paper generally relate to the field of ophthalmic imaging scanners, and more specifically, to systems for fixing the gaze direction of the eye before acquiring images of the fundus of the eye via an ophthalmic imaging scanner. background

[0002] Ophthalmic imaging scanners employ various techniques to image different parts of a subject's eye and are used by clinicians to diagnose and manage a wide range of eye conditions. Ophthalmic imaging scanners acquire images of the fundus or other parts of the eye by scanning the eye with a beam of light and detecting the reflected light from the eye. To obtain high-quality images of the fundus, ophthalmic imaging scanners, such as scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) scanners, typically require the subject to maintain a fixed gaze direction, minimizing eye movement as the fundus is imaged. Fixation may be particularly important for wide-field (WF) and ultra-wide-field (UWF) ophthalmic imaging scanners, where more time may be required to capture WF or UWF fundus images.

[0003] Therefore, ophthalmic imaging scanners typically incorporate a fixation target light source. This source projects fixation light, such as crosshairs, onto the fundus via the scanner's WF / UWF optics, providing the subject with a target to guide their gaze. However, using additional optics within the WF / UWF optics to guide the fixation light from the fixation target light source to the eye can increase system complexity and present its own engineering challenges, such as handling stray reflections that may be caused by the additional optics, which could manifest as artifacts in the acquired images.

[0004] Therefore, it is desirable to find a way to store a fixed target light source within a WF ophthalmic imaging scanner or a UWF ophthalmic imaging scanner, which at least partially solves the above-mentioned problems. Overview

[0005] According to a first exemplary aspect of this document, a UWF ophthalmic imaging instrument is provided, which is arranged to acquire UWF images of the fundus of an eye by scanning it with a light beam. The UWF ophthalmic imaging instrument includes: a light source arranged to emit a light beam; a rotatable mirror arranged to scan the fundus with the light beam; and an ellipsoidal mirror arranged to scan the fundus with the light beam via the ellipsoidal mirror, the ellipsoidal mirror having a first focal point and a second focal point, wherein, during use of the UWF ophthalmic imaging instrument, the rotatable mirror is arranged to scan the ellipsoidal mirror with the light beam via the first focal point, and the pupil of the eye is positioned at the second focal point; a fixation target light source arranged to project fixation light onto the fundus via the rotatable mirror and the ellipsoidal mirror; and at least one processor arranged to operate in a fixation mode for fixing the gaze direction of the eye, and subsequently in a fundus imaging mode to control the UWF ophthalmic imaging instrument to acquire UWF images of the fundus. In fixation mode, the at least one processor is arranged to control a rotatable mirror to remain stationary in a predetermined orientation and to control a fixation target light source to project fixation light onto the rotatable mirror in a predetermined orientation, such that the fixation light from the fixation target light source is projected onto the fundus via the rotatable mirror and an ellipsoidal mirror to fix the eye's gaze direction. In fundus imaging mode, the at least one processor is arranged to control the light source to emit a light beam and to control a UWF ophthalmic imaging instrument to acquire a UWF image of the fundus by controlling the rotatable mirror to scan the fundus with the light beam via the ellipsoidal mirror.

[0006] In some example embodiments, the rotatable mirror is arranged to reflect the light beam at a first focal point. In these embodiments, the fixation target light source can be positioned in the region between the rotatable mirror and the ellipsoidal mirror, a region not penetrated by the light beam during the acquisition of UWF images of the fundus.

[0007] In some other example embodiments, the light source is arranged to generate a light beam that provides line field illumination, and the UWF ophthalmic imaging instrument also includes a second ellipsoidal mirror. A rotatable mirror is arranged to scan the fundus with the light beam via the second ellipsoidal mirror, the second ellipsoidal mirror having a first focal point and a second focal point, wherein the rotatable mirror is arranged to reflect the light beam at the first focal point of the second ellipsoidal mirror, and the second focal point of the second ellipsoidal mirror coincides with the first focal point of the first ellipsoidal mirror. In these embodiments, the fixation target light source can be positioned in a region between the rotatable mirror and the second ellipsoidal mirror, a region not through which the light beam passes during the acquisition of UWF images of the fundus.

[0008] In the above example embodiment, the fixation target light source is located in the region between the rotatable mirror and the ellipsoidal mirror or a second ellipsoidal mirror (as the case may be), a region not penetrated by the light beam during the acquisition of UWF images of the fundus. The predetermined orientation of the rotatable mirror allows it to begin rotating from that orientation when the UWF ophthalmic imaging instrument begins acquiring UWF images of the fundus. In this case, the fixation target light source can be arranged to project fixation light from a position onto the rotatable mirror, such that when the rotatable mirror is in the predetermined orientation, the fixation light is incident on the eye in one direction to achieve central fixation. Alternatively, the fixation target light source may be operable to project fixation light onto a rotatable mirror from a selected location among a plurality of locations on the fixation target light source, the plurality of locations being arranged in directions different from the first focal point, and in fixation mode, the at least one processor may be arranged to: select a fixation direction among a plurality of different fixation directions, the eye's fixation direction being fixed in that fixation direction; determine a corresponding location among the plurality of locations using the selected fixation direction, from which the fixation target light projects fixation light onto the rotatable mirror; and control the fixation target light source to project fixation light onto the rotatable mirror from the determined location to fix the eye's fixation direction on the selected fixation direction. The plurality of different fixation directions may include a central fixation direction, and the plurality of locations on the fixation target light source may include a central location for fixing the eye's fixation direction on the central fixation direction when fixation light is projected from the central location on the fixation target light source via a predetermined-oriented rotatable mirror and via an ellipsoidal mirror onto the fundus. In addition, UWF ophthalmic imaging instruments may also include Fresnel lenses, wherein, for each position on the fixed target light source other than the central position, the Fresnel lens is arranged to refract the fixed light emitted from that position toward a common point on a rotatable mirror.

[0009] The UWF ophthalmic imaging instrument according to the first exemplary aspect or any exemplary embodiment thereof described above may further include a stereoscopic imaging device arranged to acquire a stereoscopic image of the pupil via a rotatable mirror and an ellipsoidal mirror, and a processor may further be arranged to operate in fixation mode to generate a signal based on the stereoscopic image of the pupil for bringing the pupil of the eye into a target range for acquiring an ultrawide field image of the fundus. In this case, the processor may control the stereoscopic imaging device in fixation mode to acquire a stereoscopic image of the pupil via the rotatable mirror and the ellipsoidal mirror when the rotatable mirror is stationary in a predetermined orientation; and process the stereoscopic image of the pupil to generate a signal for aligning the pupil of the eye with the imaging position.

[0010] The UWF ophthalmic imaging instruments described in any of the foregoing descriptions may include, for example, UWF scanning laser ophthalmoscopes.

[0011] According to a second exemplary aspect of this document, a method is provided for controlling a UWF ophthalmic imaging instrument to acquire a UWF image of the fundus of an eye by scanning it with a light beam. For example, the UWF ophthalmic imaging instrument may include a UWF scanning laser ophthalmoscope (SLO). The UWF ophthalmic imaging instrument includes: a light source arranged to emit a light beam; a rotatable mirror arranged to scan the fundus with the light beam; an ellipsoidal mirror arranged to scan the fundus with the light beam via the ellipsoidal mirror, the ellipsoidal mirror having a first focal point and a second focal point, wherein, during use of the UWF ophthalmic imaging instrument, the rotatable mirror is arranged to scan with the light beam via the first focal point, and the pupil of the eye is positioned at the second focal point; and a fixation target light source arranged to project fixation light onto the fundus via the rotatable mirror and the ellipsoidal mirror. The method includes: controlling a rotatable mirror to be stationary in a predetermined orientation; when the rotatable mirror is stationary in the predetermined orientation, controlling a fixation target light source to project fixation light onto the rotatable mirror, the predetermined orientation causing the fixation light to be reflected by the rotatable mirror via an ellipsoidal mirror onto the fundus to fix the gaze direction of the eye; controlling the light source to emit a light beam; and controlling a UWF ophthalmic imaging instrument to acquire a UWF image of the fundus by controlling the rotatable mirror to scan the fundus with the light beam via the ellipsoidal mirror.

[0012] In some example embodiments, the fixation target light source may be operable to project fixation light onto a rotatable mirror from a selected location among a plurality of locations on the fixation target light source, the plurality of locations being arranged in directions different from the first focal point. In this case, the method may further include: selecting a gaze direction among a plurality of different gaze directions, the gaze direction of the eye being fixed in that gaze direction; and determining a corresponding location among the plurality of locations using the selected gaze direction, from which the fixation target light will project fixation light onto the rotatable mirror; wherein the fixation target light source is controlled to project fixation light onto the rotatable mirror from the determined location in a predetermined orientation to fix the gaze direction of the eye in the selected gaze direction.

[0013] According to a third exemplary aspect of this document, a computer program including computer-readable instructions is also provided, which, when executed by a processor of a UWF ophthalmic imaging instrument of the first exemplary aspect or any exemplary embodiment thereof, cause the processor to perform the methods of the second exemplary aspect or any embodiment thereof. The computer program may be stored on a non-transitory computer-readable storage medium (e.g., such as a computer hard drive or CD) or may be carried by a computer-readable signal. Brief description of the attached diagram

[0014] 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.

[0015] Figure 1 This is a schematic diagram of an ultrawide field ophthalmic imaging instrument according to an example embodiment of this article.

[0016] Figure 2 This is a schematic diagram of programmable signal processing hardware that can be configured to perform the functions of the processor 50 described herein.

[0017] Figure 3 This is a schematic diagram showing a cross-section of the ellipsoidal mirror 32 of the example embodiment in a plane perpendicular to the axis of symmetry of the ellipsoidal mirror and including the first focal point 32-1, and a top view of the stereo imaging device 40 and the fixed target light source 80 of the example embodiment along the axis of symmetry.

[0018] Figure 4 This is a schematic diagram of a variant of an ultrawide field ophthalmic imaging instrument according to an example embodiment herein, which includes two ellipsoidal mirrors having a shared focal point, wherein a rotating mirror 30 is disposed at the remaining focal point of one ellipsoidal mirror to scan the fundus 12 with line-field illumination via a pupil 14 disposed at the remaining focal point of the other ellipsoidal mirror.

[0019] Figure 5 This is a schematic diagram of the pupil alignment module (PAM) of the UWF ophthalmic imaging instrument of an example embodiment when viewed from the rotatable mirror 30. The PAM includes a stereo imaging system 40 and includes... Figure 1 A modified version of the fixed target light source 80 in the example embodiment.

[0020] Figure 6 The flowchart illustrates a method by which processor 50 controls a UWF ophthalmic imaging instrument of an example embodiment to acquire UWF images 55 of the fundus 12 of eye 10.

[0021] Figure 7 This illustrates how processor 50 can perform in the example embodiment. Figure 6 The flowchart of process S20 shows that the fixation target light source 80 is operable to fix the light source L from a selected direction among a plurality of different directions. F The image is projected onto a rotatable mirror 30 to allow the eye to select its gaze direction. Detailed description of example embodiments

[0022] Figure 1 This is a schematic diagram of an ophthalmic imaging instrument 100 according to a first exemplary embodiment, operable to image a portion of a subject's eye 10 by scanning it with a beam of light. As in this exemplary embodiment, the imaged portion may include a region of the fundus 12 of the eye 10. The fundus 12 is the inner lining of the eye 10 opposite the lens and includes the retina, macula, optic disc, fovea, choroid, and blood vessels. The ophthalmic imaging instrument 100 may also be operable to image another portion of the eye 10, such as at least a portion of the anterior segment of the eye 10.

[0023] The ophthalmic imaging instrument 100 can be a wide-field (WF) ophthalmic imaging instrument, operable to acquire WF images of the fundus 12. The WF image of the fundus 12 is defined as a single-capture image centered on the fovea of ​​the retina of the eye 10, capturing retinal anatomy in the mid-periphery behind the vortex vein ampulla in all four quadrants of the eye 10 (i.e., the superior, inferior, nasal, and temporal quadrants). Therefore, the WF ophthalmic imaging instrument 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 formed by the imaged retinal region at the center of the eye 10 (i.e., the intersection of the vertical diameter of the eyeball and the visual axis).

[0024] As in this example embodiment, the ophthalmic imaging instrument 100 may be provided as an ultra-wide field (UWF) ophthalmic imaging instrument, which has a larger FoV than a WF instrument and is operable to acquire a UWF image of the fundus 12 covering a larger portion of the fundus 12. The UWF image of the fundus 12 is defined as a single-capture image centered on the fovea of ​​the eye 10, capturing retinal anatomy features in the distal periphery in all four quadrants, anterior to the ampulla of the vortex veins. Therefore, a UWF ophthalmic imaging instrument can acquire a UWF image that is a single-capture image 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 is defined as having an FoV (in canthal measure) between 110 and 220 degrees. For example, the Optos Dayton™ is capable of capturing a UWF image (so-called Optomap™ image) in a single capture that covers up to 200 degrees of the fundus (or approximately 82% of the retina).

[0025] It should be noted that the techniques described herein are not limited to their applicability to WF and UWF ophthalmic imaging instruments, but are also applicable to ophthalmic imaging instruments with a smaller FoV, and can benefit any scanning ophthalmic imaging instrument that scans a portion of the eye 10 with light via one or more ellipsoidal mirrors to image that portion.

[0026] In this example embodiment, the ophthalmic imaging instrument 100 includes a UWF combined scanning laser ophthalmoscopy (SLO) and an optical coherence tomography (OCT) instrument, arranged to acquire OCT images of the fundus 12 and fundus images in one or more additional modalities using known interferometric imaging techniques. Examples of such additional imaging modalities include pseudo-color imaging, fundus autofluorescence (FAF), fluorescein angiography (FA), and indocyanine green angiography (ICGA). For example, Optos Monaco™ is a combined SLO-OCT system capable of acquiring green or red (or a combination of green and red) laser views, green laser autofluorescence views, and OCT views. However, the ophthalmic imaging instrument 100 does not need to be a combined SLO-OCT system and may instead be an OCT imaging instrument operable to acquire only OCT images, or a UWF SLO operable in one or more of the aforementioned (or other) SLO imaging modalities but not in the OCT modal. Optos Daytona™ is an example of such a multimodal UWF SLO.

[0027] like Figure 1 As schematically shown, the ophthalmic imaging instrument 100 includes a light source 20, which is arranged to emit at least one light beam L. T (Understood as any directional projection) for imaging the eye 10; and an optical system including a rotatable reflector 30 and an ellipsoidal mirror 32. As in this example embodiment, a stereoscopic imaging device 40 (described in more detail below) may be provided to help bring the eye 10 to a position where it can be imaged by the ophthalmic imaging instrument 100. The optical system is arranged to project at the eye 10 with at least one beam L T Perform a scan, and collect and guide the light from the beam L. T Return light L from the area of ​​the irradiated eye 10 R For example, return light L R It could be a beam of light L that has already been reflected or scattered from the eye 10. T Part of it, or in the case of FAF and ICGA imaging modes, can be made by beam L T The light that is stimulated.

[0028] The ophthalmic imaging instrument 100 also includes at least one processor (or controller) 50, and, as in this example embodiment, may also include a beam splitter 60 and a photodetector 70. The beam splitter 60 is arranged to separate the returning light L R Part of it and will return to light L R The separated portion is guided to the photodetector 70. The UWF image 55 of the eye 10 is acquired by the ophthalmic imaging instrument 100 (e.g., by the processor 50) by processing the output of the photodetector 70 using known techniques.

[0029] The optical system may also include a drive mechanism 34, which includes, for example, a galvanometer controlled by the processor 50, to cause the rotatable mirror 30 to transmit a beam of light L through a predetermined rotational motion. T Perform a scan. As in this example embodiment, this may include a predetermined oscillating rotational motion, wherein the rotatable mirror 30 alternately rotates clockwise and counterclockwise by a predetermined angle (or, in other words, wherein the rotatable mirror 30 repeatedly rotates within an angular range defined about the mirror's axis of rotation, reversing its direction of rotation at each end of the angular range).

[0030] Light source 20 is typically arranged to generate light in one or more wavelength ranges suitable for imaging the fundus 12 (or other parts of the eye 10, as appropriate), such as the visible spectrum (e.g., red and green light) and / or the near-infrared spectrum. Light source 20 may, for example, include one or more laser diodes or one or more super-luminescent diodes (or a combination of one or more laser diodes and one or more super-luminescent diodes), and may also have one or more optical components, such as collimators, apertures, and lenses arranged to generate one or more beams. The optical system (discussed further below) may be arranged to illuminate the area of ​​the fundus 12 with a (dynamic (fly) spot or ray (in the case where the ophthalmic imaging instrument 100 is a line field (i.e., line scan) system), which is generated using cylindrical lenses or other well-known components or optical assemblies for generating line field illumination.

[0031] In an example embodiment similar to this one, the ophthalmic imaging instrument 100 can operate in OCT imaging mode and can provide a swept-frequency light source (in the case that the ophthalmic imaging instrument 100 is a swept-frequency source OCT (SS-OCT) system) or a broadband source (in the case that the ophthalmic imaging instrument 100 is a spectral domain OCT (SD-OCT) system) for OCT imaging.

[0032] The form of the photodetector 70 is not limited, and the photodetector 70 may, for example, include a balanced photodetector arrangement comprising two reverse-biased photodiodes whose output photocurrents are subtracted from each other, and the subtracted current signal is converted into a voltage detection signal by a transimpedance amplifier. In an example embodiment where the ophthalmic imaging instrument 100 is provided in the form of a line scan SLO, the photodetector 70 may include a one-dimensional or two-dimensional array of photosensitive elements. In an example embodiment similar to this one, where the ophthalmic imaging instrument 100 is characterized by an OCT imaging mode, a spectrometer (where an SD-OCT setup is used) or a photodiode detector (where an SS-OCT setup is used) may be provided to detect interference light from the sample arm and reference arm of an interferometer.

[0033] The optical system in this example embodiment is arranged to illuminate the area of ​​the fundus 12 illuminated by point scanning with light from the light source 20. T A two-dimensional point scan is performed, and light from the illuminated area is collected during the point scan. The optical system is arranged to project a beam L onto the fundus 12 via a rotatable mirror 30 and an ellipsoidal mirror 32. T A two-dimensional point scan is performed. Furthermore, the optical system includes a scanner 36 and a curved mirror 38, which are arranged to project a light beam L onto an ellipsoidal mirror 32 along a first direction via a rotatable reflector 30. T Perform a scan. As in this example embodiment, scanner 36 may be provided in the form of a polygon scanner comprising a plurality (e.g., 16) facets arranged around the periphery of a wheel rotating at high speed (typically exceeding 30,000 revolutions per minute) to perform a beam L T High-frequency repetitive scanning. However, scanner 36 can be provided in other forms, such as a galvanometer scanner, a microelectromechanical system (MEMS) scanning mirror, or a resonant scanning mirror, or, if the optical system is a line field system, can be replaced by a cylindrical lens or other beam-generating device comprising "fan" rays projected onto a flat surface to form light. As in this example embodiment, in the case where the ophthalmic imaging instrument 100 has an OCT imaging mode, a second galvanometer scanner (not in...) can be provided. Figure 1 (As shown in the figure) the OCT sample beam is used to scan the ellipsoidal mirror 32 along the first direction via the rotatable mirror 30.

[0034] Beam L TThe light is reflected sequentially by the scanner 36, the curved mirror 38, the rotatable mirror 30, and the ellipsoidal mirror 32, and then enters the fundus 12 through the pupil 14 of the eye 10. The light from the illuminated area of ​​the fundus 12 passes through the optical system along the same optical path as the beam that has entered the optical system, but in the reverse order, and a portion of it is guided to the photodetector 70 by the beam splitter 60.

[0035] Two-dimensional point scanning is performed by the scanner 36 scanning the area of ​​the fundus 12 along a first direction (e.g., the vertical direction) using a light beam L. T A scan is performed, and the rotatable mirror 30 rotates about its axis of rotation to scan the area of ​​the fundus 12 in a second direction (e.g., horizontal direction) with a beam L. T Scanning is performed (as in this example embodiment, the second direction may be orthogonal to the first direction). The ellipsoidal mirror 32 has a first focal point 32-1 and a conjugate second focal point 32-2, and as in this example embodiment, it may take the form of a spherical mirror with a rotational symmetry axis, particularly about a major axis passing through the focal point. More generally, in the example embodiment, any form of curved mirror may be used as a generalization of the ellipsoidal mirror 32, having a curvature that enables it to transmit light incident on the first focal point of the curved mirror to the conjugate second focal point. In some example embodiments, the ellipsoidal mirror 32 may be substantially spherical, with a curvature deviating to some extent from a spherical form, but this still allows the ophthalmic imaging instrument 100 to acquire WF or UWF images of the fundus 12. As in this example embodiment, the axis of rotation of the rotatable mirror 30 may be parallel to the circular symmetry axis of the spherical mirror. Therefore, when the light beam is scanned by the rotation of the rotatable mirror 30, the first focal point 32-1 and the light beam L incident on it... T The optical path length between points on the path T3 followed by the ellipsoidal mirror 32 is constant. The scanning performed by the scanner 36 and the rotatable mirror 30 can be coordinated by the processor 50 or the scanning system controller (not shown) so that the beam L... T Scanning was performed on the fundus 12 according to a predefined scanning pattern.

[0036] As in this example embodiment, the curved mirror 38 (also referred to as a slit mirror) may be an ellipsoidal mirror. Therefore, each of the curved mirror 38 and the ellipsoidal mirror 32 has a corresponding first focal point and a corresponding conjugate second focal point. The scanner 36 is arranged to reflect the light beam L at the first focal point of the curved mirror 38. T This makes the beam L T The projection on the curved mirror 38 follows Figure 1 The trajectory T1 is shown. The curved mirror 38 directs the incident light beam L onto it. TThe beam L is reflected to its second focal point, and the rotatable mirror 30 is arranged to reflect the beam L at the second focal point of the curved mirror 38. T The light beam L is reflected onto the ellipsoidal mirror 32. The rotatable mirror 30 is also arranged to reflect the light beam L at the first focus 32-1 of the ellipsoidal mirror 32. T Furthermore, the pupil 14 of the eye 10 is positioned at the second focus 32-2 of the ellipsoidal mirror 32. In the beam L... T When scanning on the curved mirror 38, the beam L T The beam L is reflected from the rotatable mirror 30 onto the ellipsoidal mirror 32, such that during each so-called "vertical scan" performed along the so-called "vertical" (or "rapid") scanning direction on the ellipsoidal mirror 32, the beam L... T The projection onto the ellipsoidal mirror 32 follows Figure 1 The trajectory T2 is shown. When the rotatable mirror 30 rotates, it causes adjacent vertical scans to shift relative to each other along the so-called "horizontal" (or "slow") scan direction, so that points with the same height in the vertical scans are aligned along... Figure 1 The path T3 is shown.

[0037] Processor 50 can be provided in any suitable form, for example, such as Figure 2 The programmable signal processing hardware 200, schematically shown herein, includes a processor 220. As described herein, the programmable signal processing hardware 200 includes a communication interface (I / F) 210 for transmitting control signals and / or data to a light source 20, a drive mechanism 34, a stereo imaging device 40, a photodetector 70, and a fixed target light source. The signal processing hardware 200 also includes a processor 220 (e.g., a central processing unit CPU and / or a graphics processing unit GPU), a working memory 230 (e.g., random access memory), and an instruction storage device 240 storing a computer program 245 comprising computer-readable instructions that, when executed by the processor 220, cause the processor 220 to perform various functions of the processor 50 described herein.

[0038] Working memory 230 stores information used by processor 220 during execution of computer program 245. Instruction storage device 240 may include a ROM (e.g., in the form of electrically erasable programmable read-only memory (EEPROM) or flash memory) preloaded with computer-readable instructions. Alternatively, instruction storage device 240 may include RAM or similar type of memory, and computer-readable instructions of computer program 245 may be input to instruction storage device from a computer program product (e.g., a non-transitory computer-readable storage medium 250 in the form of CD-ROM, DVDROM, etc.) or a computer-readable signal 260 carrying computer-readable instructions. In any case, when executed by processor 220, computer program 245 causes processor 220 to perform the functions of processor 50 as described herein. More generally, processor 50 of this example embodiment may include one or more instances of computer processor 220 and one or more instances of memory 240 storing computer-readable instructions that, when executed by computer processor 220, cause computer processor 220 to perform the functions of processor 50 as described herein. When multiple processors 220 are provided, the processors 220 can communicate with each other via any type of computer network.

[0039] However, it should be noted that processor 50 may alternatively be implemented in non-programmable hardware (such as ASICs, FPGAs, or other integrated circuits specifically designed to perform the functions of processor 50 described herein), or in such non-programmable hardware and as referenced above. Figure 2 Implemented in a combination of programmable hardware as described.

[0040] Refer again Figure 1The stereoscopic imaging device 40 may form part of a so-called pupil alignment module (PAM) and includes a first camera 42 and a second camera 44 arranged to acquire corresponding stereoscopic images 46-1 and 46-2 of the pupil 14 and the surrounding portion of the eye 10 (including at least some of the iris and generally some of the sclera) via a rotatable mirror 30 and an ellipsoidal mirror 32. As in this example embodiment, the stereoscopic imaging device 40 may also have an illumination source 47 that illuminates the eye 10 with light via the rotatable mirror 30 and the ellipsoidal mirror 32, the reflection of which is detected by the first camera 42 and the second camera 44 to acquire corresponding stereoscopic images 46-1 and 46-2 of the pupil 14. For patient comfort and to avoid pupillary constriction, the illumination is typically in the infrared (IR) band and may be provided by an illumination source 47 in the form of, for example, an IR light-emitting diode (LED). Stereo cameras 42 and 44 can employ complementary metal-oxide-semiconductor (CMOS) sensors and fast lenses with fixed focal lengths to compensate for the relatively low sensitivity of the sensors to IR illumination typically provided by an illumination source.

[0041] The ophthalmic imaging instrument 100 also includes a fixation target light source 80 (e.g., as part of PAM), which includes one or more light sources, such as, for example, light-emitting diodes (LEDs). The fixation target light source 80 is arranged to project the fixation light L via a rotatable reflector 30 and an ellipsoidal mirror 32. F Projected onto the fundus 12. Fixation on the target light L. F The projection on the fundus 12 has a predetermined shape selected to help the subject maintain a stable gaze direction. This predetermined shape may include, for example, one or more of a crosshair, dot, disc, or circle. As described below, fixation light L... F The color can be changed by the processor 50.

[0042] The processor 50 is configured to operate in patient alignment mode to control the drive mechanism 34 to rotate the rotatable mirror 30 to a predetermined orientation (if the rotatable mirror 30 is not already in that orientation) and hold the rotatable mirror 30 stationary in the predetermined orientation, while controlling the stereo imaging device 40 to simultaneously (or with a small delay between acquiring two images, not significantly affecting stereo distance measurement) acquire stereo images 46-1 and 46-2 of the pupil 14 via the rotatable mirror 30 and the ellipsoidal mirror 32. The processor 50 controls the stereo imaging device 40 to maintain the acquisition of stereo images of the pupil 14 during operation in patient alignment mode. The processor 50 is also configured to process the acquired stereo images to generate a signal S for bringing the pupil 14 into a target range suitable for acquiring a UWF image 55 of the fundus 12.

[0043] When the rotatable mirror 30 remains stationary in a predetermined orientation in patient alignment mode (also referred to herein as fixation mode, or patient alignment and fixation mode), the processor 50 is also arranged to control the fixation target light source 80 to fixate the fixation light L. F The light is projected onto the rotatable mirror 30, specifically onto the first focal point 32-1 of the ellipsoidal mirror 32. The fixed target light source 80 is positioned relative to the rotatable mirror 30 in a predetermined orientation, such that the fixed light L... F The fixation target light source 80 is projected onto the fundus 12 via a rotatable reflector 30 and an ellipsoidal mirror 32 to fix the gaze direction of the eye 10, thereby keeping the eye 10 stable when the pupil 14 is brought into the target range suitable for acquiring an ultra-wide field image 55 of the fundus 12 based on the signal S. As in this example embodiment, the fixation target light source 80 can be arranged to project the fixation light L F The light is projected from one position onto the rotatable mirror 30, such that when the rotatable mirror 30 is in a predetermined orientation, the fixed light L... F The light is incident on the eye 10 in one direction to fix the gaze direction of the eye 10 to the central gaze direction used by the subject when looking straight ahead. However, as shown in the following reference... Figure 5 As explained, the fixation target light source 80 can be configured to provide fixation in fixation directions other than the central fixation direction.

[0044] In patient alignment mode, as in this example embodiment, processor 50 can use any known stereo ranging technique to process the stereo images acquired by stereo imaging device 40, which uses the concepts of parallax and triangulation to estimate distances and determine an indication of the distance d between the exit pupil of ophthalmic imaging instrument 100 and the pupil 14 of eye 10. For example, processor 50 can determine the indication of distance d by processing each of the acquired stereo images 46-1 and 46-2 to locate the corresponding pupil center in the image (e.g., using edge detection to determine the pupil outline and fitting a circle to the outline to find the center); mapping the located pupil centers to a common image frame; determining the interval between pupil centers in the common image frame; and using the determined interval to determine the indication of distance d, which is inversely proportional to distance d. The processor 50 can then compare the determined distance d with a predetermined threshold to determine whether the pupil 14 is too close to the exit pupil position of the ophthalmic imaging instrument 100, too far from the exit pupil position, or within a predetermined distance range from the exit pupil position, which is acceptable for image acquisition. As in this example embodiment, the processor 50 can then generate a signal S to control the fixation target light source 80 to output fixation light indicating the color of the comparison result. For example, the processor 50 can control the fixation target light source 80 to emit a first color (e.g., blue) fixation light when the distance between the exit pupil E of the ophthalmic imaging instrument 100 and the pupil 14 is greater than a threshold at the end of the defined range R and the pupil 14 is located on the side of the range R further away from the ophthalmic imaging instrument 100; to emit a second different color (e.g., red) fixation light when the distance between the exit pupil E and the pupil 14 is greater than the threshold and the pupil 14 is located on the other side of the range R closer to the ophthalmic imaging instrument 100; and to emit yet another color (e.g., green) fixation light when the distance between the exit pupil E and the pupil 14 is less than the threshold. Although the exit pupil position is referenced herein, any other reference point of the ophthalmic imaging instrument 100 may be used alternatively, and the pupil 14 needs to be positioned near that reference point to obtain an image 55 of the fundus 12 of the eye 10.

[0045] Additionally or alternatively, processor 50 may generate control signals S to control the speaker (not in...). Figure 1(As shown in the diagram) The speaker generates a sound (e.g., a changing tone or spoken word) to indicate the comparison result. For example, the speaker may be controlled by the processor 50 to generate a first tone (e.g., a low tone) or spoken word indication, for example, when the distance between the exit pupil E and the pupil 14 of the ophthalmic imaging instrument 100 is greater than a threshold and the pupil 14 is located on the side of the range R further away from the ophthalmic imaging instrument 100; to generate a different second tone (e.g., a high tone) or spoken word indication when the distance between the exit pupil E and the pupil 14 is greater than the threshold and the pupil 14 is located on the other side of the range R closer to the ophthalmic imaging instrument 100; and to generate other tones (e.g., a mid-tone) or spoken word indication when the distance between the exit pupil E and the pupil 14 is less than the threshold.

[0046] By processing each pair of acquired stereoscopic images as described above, the patient can be appropriately guided to move their eyes 10 backward (away from the ophthalmic imaging instrument 100) or forward (towards the ophthalmic imaging instrument 100) until the patient observes the fixation light as green and / or hears a mid-tone or verbal instruction (as the case may be), and the patient is notified that the pupil 14 of the eye 10 is close enough to the exit pupil (or other reference point) of the ophthalmic imaging instrument 100 to begin UWF imaging of the fundus 12.

[0047] After the distance between the exit pupil position and the pupil 14 has been determined to be less than a threshold, the processor 50 is configured to begin operating in fundus imaging mode to control the ophthalmic imaging instrument 100 to acquire UWF images 55 of the fundus 12. The processor 50 does this by controlling the light source 20 to begin emitting a light beam L. T And controlling the ophthalmic imaging instrument 100 to project a beam L onto the fundus 12 via the scanner 36 and the rotatable mirror 30 through the ellipsoidal mirror 32. T A scan is performed to acquire a UWF image 55 of the fundus 12. The processor 50 preferably controls the fixation target light source 80 to stop emitting fixation light L. F (beam L is emitted from light source 20) T (Before or after) to reduce artifacts and otherwise improve the quality of the UWF image 55. To reduce the risk of the eye 10 becoming misaligned with the ophthalmic imaging instrument 100, as in this example embodiment, the processor 50 may, in response to determining that the distance d between the exit pupil and the pupil 14 of the ophthalmic imaging instrument 100 is less than a threshold, begin automatic operation in fundus imaging mode. However, in other example embodiments, this switching of operating mode may be indicated by the operator of the ophthalmic imaging instrument 100 in response to visual, audio, and / or tactile feedback based on signal S, such as by the operator clicking a mouse button or pressing a key on a computer keyboard communicatively coupled to the processor 50.

[0048] As in this example embodiment, the stereoscopic imaging device 40 may be located in region G between the rotatable mirror 30 and the ellipsoidal mirror 32, which is not obstructed by the beam L during the acquisition of the UWF image 55 of the fundus 12. T Through. As in this example embodiment, the fixation target light source 80 may also be located within region R. Therefore, the stereo imaging device 40 and the fixation target light source 80 can be accommodated in an area not used for beam propagation within the bowl of the ellipsoidal mirror 32. This arrangement can advantageously make the ophthalmic imaging instrument 100 more compact by placing the stereo imaging device 40 and the fixation target light source 80 in other unused areas of the ophthalmic imaging instrument 100.

[0049] Furthermore, by housing the stereo imaging device 40 and the fixation target light source 80 in region G, the following option is achieved: Orienting the rotatable mirror 30 in patient alignment mode (i.e., selecting the aforementioned predetermined orientation) such that, during operation of the processor 50 in fundus imaging mode, once the UWF ophthalmic imaging instrument 100 begins acquiring UWF images 55, the rotatable mirror 30 begins to rotate from the predetermined orientation. Therefore, delays in image acquisition start-up due to the rotatable mirror 30 rotating from the predetermined orientation used in patient alignment mode to a (different) starting orientation for image acquisition can be avoided, thereby reducing the risk of changes in the gaze direction of the eye 10. However, this advantage can be offset by the need for easy access to the stereoscopic imaging device 40 or the fixation target light source 80 for maintenance and / or adjustment. For example, in some example embodiments, the stereoscopic imaging device 40 and the fixation target light source 80 may alternatively be located outside the bowl of the ellipsoidal mirror 32, wherein the predetermined orientation of the rotatable mirror 30 used in patient alignment mode is configured to still allow the stereoscopic imaging device 40 to acquire stereoscopic images 46-1 and 46-2 of the pupil 14 via the rotatable mirror 30 and the ellipsoidal mirror 32 while the eye 10 remains fixed. For example, the stereoscopic imaging device 40 and the fixation target light source 80 may be located within the ellipsoidal mirror (e.g., similar to...). Figure 1 The curved mirror 38 is positioned above the edge of the rotatable mirror 30 so that each has a line of sight to the rotatable mirror 30. Alternatively, the stereo imaging device 40 and the fixed target light source 80 may be located on the non-reflective side of the ellipsoidal mirror 32, wherein one or more holes are provided in the ellipsoidal mirror 32 to allow light to pass through the ellipsoidal mirror 32 to reach the stereo imaging device 40 and pass through the fixed target light source 80.

[0050] When the UWF ophthalmic imaging instrument 100 begins acquiring UWF images 55, regardless of whether the rotatable mirror 30 is oriented in patient alignment mode to allow the rotatable mirror 30 to begin rotating from a predetermined orientation, it may be advantageous to position the stereo imaging device 40 between the rotatable mirror 30 and the ellipsoidal mirror 32, a position that minimizes the roundness deviation of the individual representations of the pupil 14 in the stereo images 46-1 and 46-2 acquired by the stereo imaging device 40 when the rotatable mirror 30 is in the predetermined orientation. This positioning of the stereo imaging device 40 brings its viewpoint as close as possible to the central gaze direction of the eye 10, thus allowing the pupil 14 in images 46-1 and 46-2 to be as circular as possible, which can facilitate the process of locating the pupil center and therefore help to accurately calculate the distance between the pupil 14 and the exit pupil of the ophthalmic imaging instrument 100.

[0051] As an example, the ellipsoidal mirror 32 of this example embodiment has a symmetry plane P including a first focus 32-1 and a second focus 32-2, and when the rotatable mirror 30 is in a predetermined orientation, the normal direction N of the rotatable mirror 30 at the first focus 32-1 is subtended by a predetermined angle relative to the symmetry plane P. ,like Figure 3 As shown. For clarity, in Figure 3 The following discussion exaggerates the perspective. and angle The size of the first camera 42 and the second camera 44 are arranged symmetrically around a second plane P2 passing through the first focal point 32-1 and the second focal point 32-2. As in this example embodiment, the first camera 42 and the second camera 44 may include respective camera lenses having corresponding optical axes 48-1 and 48-2, which are parallel to each other and arranged equidistant from the second plane P2 and on opposite sides of the second plane P2. However, in other example embodiments, both optical axes 48-1 and 48-2 may lie within the second plane P2. The angle between the normal direction N of the rotatable mirror 30 and the second plane P2 at the first focal point 32-1. Less than the predetermined angle In the case of twice the size, it was found that the roundness deviation of the various representations of the pupil 14 in the stereoscopic images 46-1 and 46-2 of the pupil 14 obtained using this arrangement was small enough to allow for satisfactory pupil alignment.

[0052] It should be noted that although the rotatable mirror 30 is configured to reflect the light beam L on the ellipsoidal mirror 32 at the first focus 32-1 of the ellipsoidal mirror 32, T However, the optical system of the ophthalmic imaging instrument 100 can be arranged such that the rotatable mirror 30 is transmitted via a beam L through the first focal point 32-1 in another manner. T Perform a scan. Figure 4This is a schematic diagram of a modified line-scan UWF ophthalmic imaging instrument 300 according to an exemplary embodiment. In addition to the ellipsoidal mirror 32, the instrument includes a second ellipsoidal mirror 39, and a rotatable mirror 30 is arranged to project a light beam L onto the fundus 12 via the second ellipsoidal mirror 39. T 'Perform a scan. In this case, beam L T The projection on a plane perpendicular to its propagation direction (i.e., the cross-section) is a line, and can be generated using a cylindrical lens from a beam of light with a spot (such as that generated by light source 20), or using another optical device known to those skilled in the art for generating line field illumination (e.g., a backlight slit stop). Figure 4 As shown, the second ellipsoidal mirror 39 has a first focus 39-1 and a second focus 39-2, wherein the rotatable mirror 30 is arranged to reflect the light beam L at the first focus 39-1 of the second ellipsoidal mirror 39. T The second focus 39-2 of the second ellipsoidal mirror 39 coincides with the first focus 32-1 of the ellipsoidal mirror 32.

[0053] Generates line field lighting L T 'Light source 20' in Figure 4 As shown in the image, and this is in place of... Figure 1 The example embodiment provides for the light source 20, scanner 36, and curved mirror 38. The line-scanning UWF ophthalmic imaging instrument 300 includes the remaining components of the UWF ophthalmic imaging instrument 100, although these components are not included in the example embodiment. Figure 4 The diagram illustrates, for clarity, the different scanning transmission arrangements comprising two ellipsoidal mirrors 32 and 39. The line-scan UWF ophthalmic imaging instrument 300 also features a beam splitter to direct the returning light from the fundus 12 to a photodetector for detecting the returning line field illumination, although, for clarity, a similar arrangement is shown from... Figure 4 The beam splitter is omitted in the text.

[0054] In the online scanning UWF ophthalmic imaging instrument 300, the fixation target light source 80 and the stereo imaging device 40 (if provided) can be housed in an area not covered by the beam L. T The light passes through region G2 (between the second ellipsoidal mirror 39 and the rotatable mirror 30). The fixation target light source 80 and the stereo imaging device 40 (if provided) can be arranged relative to the rotatable mirror 30 and configured to operate as described above, although light propagates from the eye 10 to the stereo imaging device 40 and the fixation light L. F The light from the fixed target light source 80 to the eye 10 must pass through the second ellipsoidal mirror 39 and the ellipsoidal mirror 32.

[0055] Alternatively, if there is not enough space inside the bowl of the second ellipsoidal mirror 39, one or both of the stereo imaging device 40 and the fixed target light source 80 may be located in region G2' on the non-reflective side of the second ellipsoidal mirror 39, wherein one or more holes are provided in the second ellipsoidal mirror 39 to allow light to pass through the second ellipsoidal mirror 39 to reach the stereo imaging device 40 and from the fixed target light source 80 through the second ellipsoidal mirror 39.

[0056] Regardless of whether the stereoscopic imaging device 40 is housed in region G (or Figure 4 In the variant region G2), as in this example embodiment, the stereo imaging device 40 may further include a Fresnel lens 49 disposed between the rotatable mirror 30 and both the first camera 42 and the second camera 44. Figure 1 In an example embodiment, a Fresnel lens 49 is arranged to refract light from the eye 10, which has been reflected by a rotatable mirror 30 at a first focal point 32-1 of an ellipsoidal mirror 32, to propagate along a first optical axis 48-1 of the first camera 42 and a second optical axis 48-2 of the second camera 44. The Fresnel lens 49 allows the first camera 42 and the second camera 44 to be easily mounted on a support circuit board or other flat substrate, wherein their respective optical axes are perpendicular to the surface of the substrate. The time-consuming process of carefully aligning the optical axes of the first camera 42 and the second camera 44 through the first focal point 32-1 of the ellipsoidal mirror 32 can be avoided, which might otherwise be necessary to improve stereo ranging, and thus makes the manufacture of the stereo imaging device 40 simpler and faster. Similarly, referring to the above... Figure 4 In the described variant, the Fresnel lens 49 can be positioned between the rotatable mirror 30 and both the first camera 42 and the second camera 44 located in region G2, and is arranged to refract light from the eye 10, which has been reflected by the rotatable mirror 30 at the first focal point 39-1 of the second ellipsoidal mirror 39, to propagate along the first optical axis 48-1 of the first camera 42 and along the second optical axis 48-2 of the second camera 44.

[0057] Although in the above example embodiments and variations thereof, the fixation target light source 80 is operable to fixate the fixation light L F Projecting from a single location onto a rotatable mirror 30 for central fixation, but the fixation target light source 80 can alternatively be configured to project the fixation light L... F The projected image is directed from a selected position among multiple positions on the fixed target light source 80 onto the rotatable reflector 30, these multiple positions being arranged at the first focus 32-1 of the ellipsoidal mirror 32 (or at... Figure 4 The corresponding direction is different from the first focus 39-1 of the second ellipsoidal mirror 39 in the variant.

[0058] Figure 5This is a schematic diagram of PAM 400 as viewed from the rotatable mirror 30, which includes... Figure 1 The example embodiment includes a modified version of the stereo imaging system 40 and the fixed target light source 80. For example... Figure 5 As shown, the PAM 400 includes a flat substrate 410 on which a first camera 42 and a second camera 44 are mounted, and an IR illumination source 47 for illuminating the eye 10, such that the eye 10 can be imaged by the stereo cameras 42 and 44. The fixation target light source 80 includes multiple individual fixation light sources in the form of LEDs. Figure 5 These are labeled 80-1 to 80-9. Each of these fixed-target light sources can produce at least three colors of visible light (e.g., red, green, and blue). Figure 5 In the example, LEDs 80-1 to 80-9 are RGB LEDs, each capable of emitting red, green, or blue light under the control of processor 50. Despite the existence of... Figure 5 The example shows nine such light sources, but their number and arrangement are not so limited. As in this example, the PAM400 may also include the aforementioned Fresnel lens 49, which covers the stereo cameras 42 and 44, the IR illumination source 47, and the LEDs 80-1 to 80-9, such that the lens is positioned between these components and the rotatable reflector 30.

[0059] LEDs 80-1 to LEDs 80-9 are positioned at different corresponding locations, and these locations are arranged in accordance with... Figure 1 The first focus 32-1 (or) in the example embodiment Figure 4 In the variant, the first focal point 39-1 of the second ellipsoidal mirror 39 is in a different corresponding direction, so that the eye 10 can gaze at the selected LED from the LED via the rotatable reflector 30 and the ellipsoidal mirror 32 (and Figure 4 The second ellipsoidal mirror 39 in the variant relays light to the eye 10 and manipulates it in different directions. Figure 5 In the example, LED 80-5 is arranged to provide central fixation, while the remaining LEDs are arranged to guide the patient to look left, right, straight up, up and left, up and right, straight down, down and left, and down and right.

[0060] However, it should be noted that the fixation target light source 80 can be arranged in other ways to fix the fixation light L F The image is projected from a selected position among multiple positions on the fixed target light source 80 onto the rotatable reflector 30. These positions are arranged at the first focus 32-1 of the ellipsoidal mirror 32 (or at...). Figure 4In the variant, the fixed target light source 80 is located in directions different from the first focal point 39-1 of the second ellipsoidal mirror 39. For example, the fixed target light source 80 can be provided as an alternative to at least one display screen (e.g., an LED display screen of a liquid crystal display (LCD), organic LED (OLED) display screen), which can be controlled by the processor 50 to project a fixed light L from a selected portion of a plurality of individual portions on the display screen. F Furthermore, in some cases, it projects light of a selected color from among multiple available colors. As another example, the fixation target light source 80 can be provided in the form of an optical fiber arrangement, which can exit from the substrate 410 at the same location as LEDs 80-1 to 80-9, and the light guided through it will be projected toward a rotatable reflector 30, which provides an optical switch or other device controllable by a processor 50 to allow the fixation light L from the selected optical fiber to be projected. F It is incident on the rotatable reflector 30.

[0061] In patient alignment mode, processor 50 is configured to select a gaze direction from multiple different gaze directions, fix the gaze direction of eye 10 on that gaze direction, and use the selected gaze direction to determine a corresponding position among multiple locations. Fixation target light source 80 will then apply fixation light L from that corresponding position. F The projection is onto the rotatable reflector 30. Figure 5 In the example, processor 50 can select one of LEDs 80-1 to LED 80-9, which corresponds to the selected gaze direction. Then, processor 50 can control fixation target light source 80 to project fixation light L from the determined position. F The light is projected onto a rotatable mirror 30 to fix the gaze direction of the eye 10 in the selected gaze direction, for example, by driving only the selected LED to emit a target fixation light L. F .

[0062] Multiple different gaze directions may include a central gaze direction, and multiple positions fixed on the target light source 80 may include a central position (i.e., Figure 5 The example shows the position of LED 80-5, used when the fixed-beam L F When the light is projected from the central position onto the fundus 12 via a rotatable reflector 30 of predetermined orientation and an ellipsoidal mirror 32, the gaze direction of the eye 10 is fixed on the central gaze direction. For each position on the fixation target light source 80 other than the central position, the Fresnel lens 49 is arranged to fixate the fixation light L emitted from that position. F The refraction propagates toward a common point on the rotatable mirror 30. This common point corresponds to the first focal point of the ellipsoidal mirror 32 in the above example embodiment, and a reference point. Figure 4The first focal point 39-1 of the second ellipsoidal mirror 39 in its variant is described. Therefore, the Fresnel lens 49 can provide the reflected light from the eye 10 for forming stereoscopic images 46-1 and 46-2, and the fixation light L for fixing the gaze direction of the eye 10. F The necessary focus on both avoids the need for separate optics for the stereo imaging device 40 and the fixed target light source 80.

[0063] Figure 6 This is a flowchart outlining the operations performed by processor 50 as described above to control the UWF ophthalmic imaging instrument 100 to acquire UWF images 55 of the fundus 12. For clarity, some actions and processes described above that can be taken / executed by processor 50 in the context of these operations will not be described here again, but are to be understood as forming the basis of the following references. Figure 6 Optional features of the described operation. The processor 50 can similarly control the ophthalmic imaging instrument 300 to acquire UWF images 55 of the fundus 12.

[0064] The processor 50 operates in fixed-view mode to control (in) first. Figure 6 In S10, the rotatable mirror 30 is stationary in a predetermined orientation to fix the gaze direction of the eye 10. Then, in Figure 6 In S20, when the rotatable reflector 30 is in a predetermined orientation, the processor 50 controls the fixation target light source 80 to fix the fixation light L. F The light is projected onto the rotatable mirror 30. The predetermined orientation causes the fixation light L from the light source 80 on the fixation target to... F Via the rotatable mirror 30 and the ellipsoidal mirror 32 (and referenced above) Figure 4 The second ellipsoidal mirror 39 in the described variant is projected onto the fundus 12 to fix the gaze direction of the eye 10.

[0065] In this embodiment, the fixed target light source 80 is operable to select a position from a plurality of positions on the fixed target light source 80 (the plurality of positions are arranged with respect to the first focal point 32-1 (or...) Figure 4 In the variant (different from the first focal point 39-1) in various directions, the fixation light L will be fixed. F In an example embodiment where the projection is onto the rotatable reflector 30, the processor 50 can be arranged to perform actions such as... Figure 7 As shown Figure 6 Process S20: Select a gaze direction from multiple different gaze directions, and the gaze direction of eye 10 will be fixed in that gaze direction (in Figure 7 In S22); using the selected gaze direction to determine the corresponding position among multiple positions, the fixation target light source 80 will fixate the light L from that position. F Projected onto the rotatable mirror 30 (in Figure 7 (in S24); and control the fixation target light source 80 to move the fixation light L from the determined position. F The projection is onto the rotatable mirror 30 to fix the gaze direction of the eye 10 in the selected gaze direction (in Figure 7 (in S26).

[0066] Refer again Figure 6 In response to an instruction from the operator of the ophthalmic imaging instrument 100 or automatically in response to determining that the distance between the exit pupil position and the pupil 14 of the UWF ophthalmic imaging instrument 100 is less than a threshold (or automatically after a predetermined time period), the processor 50 first controls the light source 20 to emit a light beam L. T (In process S30). Then, in S40, the processor 50 controls the ophthalmic imaging instrument 100 to rotate the rotatable mirror 30 via the ellipsoidal mirror 32 (and in Figure 4 In the variant, the beam L is applied to the fundus 12 via the second ellipsoidal mirror 39. T A scan is performed to acquire a UWF image 55 of the fundus 12. Before acquiring the UWF image 55, the processor 50 preferably turns off the fixation target light source 80 and the IR illumination source 47 (if provided).

[0067] 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.

[0068] In one example embodiment, some aspects of the examples given herein (such as the functionality of processor 50) may be provided as a computer program or software, such as one or more programs having instructions or sequences of instructions, included or stored in an article of manufacture, such as a machine-accessible or machine-readable medium, an instruction storage device, or a computer-readable storage device, each of which may be non-transitory. Programs or instructions on a non-transitory machine-accessible medium, machine-readable medium, instruction storage device, or computer-readable storage device can be used to program a computer system or other electronic device. Machine-readable media or computer-readable media, instruction storage devices, and storage devices may include, but are not limited to, optical discs and magneto-optical discs, or other types of media / machine-readable media / instruction storage devices / storage devices suitable for storing or transmitting electronic instructions. The techniques described herein are not limited to any particular software configuration. They may be applied in any computing or processing environment. As used herein, the terms “computer-readable,” “machine-accessible medium,” “machine-readable medium,” “instruction storage device,” and “computer-readable storage device” shall include any medium capable of storing, encoding, or transmitting instructions or sequences of instructions for execution by a machine, computer, or computer processor and causing the machine / computer / computer processor to perform any of the methods described herein.

[0069] Computer program products may be provided in the form of one or more storage media, instruction storage devices, or storage apparatuses that store, on or therein, instructions for controlling or causing a computer or computer processor to perform any of the processes described in the exemplary embodiments herein. Storage media / instruction storage devices / storage apparatuses may, by way of example and without limitation, include optical discs, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory, flash memory cards, magnetic cards, optical cards, nanosystems, molecular memory integrated circuits, RAID, remote data storage / archiving / warehouse devices, and / or any other type of device suitable for storing instructions and / or data.

[0070] Regarding storage on any of one or more computer-readable media, instruction storage devices, or storage devices, some embodiments include hardware for controlling the system and software for enabling the system or microprocessor to interact with a human user or other entity using the results of the exemplary embodiments described herein. Such software may, without limitation, include device drivers, operating systems, and user applications. Finally, as described above, such computer-readable media or storage devices also include software for performing exemplary aspects of the invention.

[0071] The system's programming and / or software includes software modules for implementing the processes described herein. In some example embodiments herein, the modules comprise software, but in other example embodiments herein, the modules comprise hardware or a combination of hardware and software.

[0072] 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.

[0073] In some situations, multitasking and parallel processing may be advantageous. Furthermore, the separation of the various components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Claims

1. An ultra-wide field ophthalmic imaging instrument (100; 300), which is arranged to transmit light (L) onto the fundus (12) using a beam (L T L T The ultrawide field image (55) of the fundus (12) of the eye (10) is obtained by scanning, the ultrawide field ophthalmic imaging instrument comprising: The light source (20; 20') is arranged to emit a beam (L) T ; L T ’）； A rotatable reflector (30) is arranged to project a light beam (L) onto the fundus (12). T L T Perform a scan; An ellipsoidal mirror (32), the rotatable mirror (30) is arranged to project a light beam (L) onto the fundus (12) via the ellipsoidal mirror (32). T L T The ellipsoidal mirror (32) is used for scanning, having a first focal point (32-1) and a second focal point (32-2), wherein during the use of the ultra-wide field ophthalmic imaging instrument (100; 300), the rotatable mirror (30) is arranged to scan the ellipsoidal mirror (32) with a beam (L) via the first focal point (32-1) on the ellipsoidal mirror (32). T L T The eye (10) is scanned, and the pupil (14) of the eye (10) is positioned at the second focal point (32-2); A fixed target light source (80) is arranged to reflect the fixed light (L) via the rotatable reflector (30) and the ellipsoidal mirror (32). F ) projected onto the fundus (12); and A processor (50) is configured to operate in a fixation mode for fixing the gaze direction of the eye (10) and subsequently in a fundus imaging mode to control the ultrawide field ophthalmic imaging instrument (100; 300) to acquire the ultrawide field image (55) of the fundus (12), wherein In the fixation mode, the processor (50) is arranged to control the rotatable mirror (30) to remain stationary in a predetermined orientation and to control the fixation target light source (80) to direct the fixation light (L) F The fixed light (L) from the fixed target light source (80) is projected onto the rotatable mirror (30) in the predetermined orientation, the predetermined orientation causing the fixed light (L) from the fixed target light source (80) to be projected onto the rotatable mirror (30) in the predetermined orientation. F The image is projected onto the fundus (12) via the rotatable mirror (30) and the ellipsoidal mirror (32) to fix the gaze direction of the eye (10), and In the fundus imaging mode, the processor (50) is arranged to control the light source (20; 20') to emit a beam (L). T L T '), and control the ultra-wide field ophthalmic imaging instrument (100; 300) to control the rotatable mirror (30) via the ellipsoidal mirror (32) to project a beam (L) onto the fundus (12). T L T A scan is performed to obtain the ultrawide field image (55) of the fundus (12).

2. The ultra-wide field ophthalmic imaging instrument (100) according to claim 1, wherein, The rotatable mirror (30) is arranged to reflect the light beam (L) at the first focal point (39-1). T ).

3. The ultra-wide field ophthalmic imaging instrument (100) according to claim 2, wherein, The fixed target light source (80) is located in a region (R) between the rotatable mirror (30) and the ellipsoidal mirror (32), which is not affected by the beam (L) during the acquisition of the ultrawide field image (55) of the fundus (12). T (Pass through) 4. The ultra-wide field ophthalmic imaging instrument (300) according to claim 1, wherein, The light source (20') is arranged to produce a light beam (L T ') makes the beam (L) T The ultrawide field ophthalmic imaging instrument (300) provides linear field illumination, and the rotatable mirror (30) further includes a second ellipsoidal mirror (39), the second ellipsoidal mirror (39) being arranged to illuminate the fundus (12) with a beam (L) via the second ellipsoidal mirror (39). T The second ellipsoidal mirror (39) is used for scanning, and has a first focal point (39-1) and a second focal point (39-2), wherein the rotatable mirror (30) is arranged to reflect the light beam (L) at the first focal point (39-1) of the second ellipsoidal mirror (39). T '), and the second focus (39-2) of the second ellipsoidal mirror (39) coincides with the first focus (32-1) of the first ellipsoidal mirror (32).

5. The ultra-wide field ophthalmic imaging instrument (300) according to claim 4, wherein, The fixed target light source (80) is located in a region (R) between the rotatable mirror (30) and the second ellipsoidal mirror (39), which is not affected by the beam (L) during the acquisition of the ultrawide field image (55) of the fundus (12). T ') Pass through.

6. The ultra-wide field ophthalmic imaging instrument (100; 300) according to claim 2 or claim 5, wherein, The predetermined orientation of the rotatable mirror (30) is such that when the ultrawide field ophthalmic imaging instrument (100; 300) begins to acquire the ultrawide field image (55) of the fundus (12), the rotatable mirror (30) begins to rotate from the predetermined orientation.

7. The ultra-wide field ophthalmic imaging instrument (100; 300) according to claim 6, wherein, The fixation target light source (80) is arranged to direct the fixation light (L) F The fixed beam (L) is projected from a position onto the rotatable mirror (30) such that when the rotatable mirror (30) is in the predetermined orientation, the fixed beam (L) is projected onto the rotatable mirror (30) from a position such that ... when the rotatable mirror (30) is in the predetermined orientation, the fixed beam (L) is projected onto the rotatable mirror (3 F The light is incident on the eye (10) in one direction so that the eye (10) is fixed in a central gaze.

8. The ultra-wide field ophthalmic imaging instrument (100; 300) according to any one of claims 1 to 6, wherein: The fixation target light source (80) is operable to direct the fixation light (L) from a selected position among a plurality of positions on the fixation target light source (80). F The projection is onto the rotatable mirror (30), and the plurality of positions are arranged in directions different from the first focal point (32-1). In the fixed-view mode, the processor (50) is arranged as follows: (S22) Select a gaze direction from multiple different gaze directions, and the gaze direction of the eye (10) will be fixed in the gaze direction; Using the selected gaze direction to determine (S24) the corresponding position among the plurality of positions, the fixation target light source (80) will project the fixation light (L) from that position. F ) projected onto the rotatable mirror (30); and Control (S26) the fixation target light source (80) to fix the fixation light (L F The eye (10) is projected from the determined position onto the rotatable mirror (30) to fix the gaze direction of the eye (10) in the selected gaze direction.

9. The ultra-wide field ophthalmic imaging instrument (100; 300) according to claim 8, wherein, The plurality of different gaze directions include a central gaze direction, and the plurality of positions on the fixation target light source (80) include a central position for use when the fixation light (L F When the gaze direction of the eye (10) is fixed on the central gaze direction, the retinal (12) is projected from the central position on the fixed target light source (80) via the rotatable reflector (30) with the predetermined orientation and via the ellipsoidal mirror (32).

10. The ultra-wide field ophthalmic imaging instrument (100; 300) according to claim 9 further includes a Fresnel lens (49), wherein, For each position on the fixed target light source (80) other than the central position, the Fresnel lens (49) is arranged to refract the fixed light (L) emitted from that position. F () propagates toward a common point on the rotatable reflector (30).

11. The ultra-wide field ophthalmic imaging instrument (100; 300) according to any one of the preceding claims further includes: A stereoscopic imaging device (40) is arranged to acquire a stereoscopic image (46-1; 46-2) of the pupil (14) via the rotatable mirror (30) and the ellipsoidal mirror (32). in The processor (50) is also arranged to operate in the fixation mode to generate a signal (S) based on the stereoscopic image (46-1; 46-2) of the pupil (14), the signal (S) being used to bring the pupil (14) of the eye (10) into a target range for acquiring the ultrawide field image (55) of the fundus (12), and In the fixed-view mode, the processor (50) is further arranged as follows: The stereoscopic imaging device (40) is controlled to acquire the stereoscopic image (46-1; 46-2) of the pupil (14) via the rotatable mirror (30) and the ellipsoidal mirror (32) when the rotatable mirror (30) is stationary in the predetermined orientation; and The stereoscopic image (46-1; 46-2) of the pupil (14) is processed to generate the signal (S) for aligning the pupil (14) of the eye (10) with the imaging position.

12. The ultra-wide field ophthalmic imaging instrument (100; 300) according to any one of the preceding claims, wherein, The ultra-wide field ophthalmic imaging instrument (100; 300) includes an ultra-wide field scanning laser ophthalmoscope.

13. A controllable ultrawide field ophthalmic imaging instrument (100; 300) uses a beam (L) on the fundus (12) T L T A method for scanning to acquire ultrawide field images (55) of the fundus (12) of the eye (10), the ultrawide field ophthalmic imaging instrument (100; 300) comprising: The light source (20) is arranged to emit a beam (L) T L T '); A rotatable reflector (30) is arranged to project a light beam (L) onto the fundus (12). T L T Perform a scan; An ellipsoidal mirror (32), the rotatable mirror (30) is arranged to project a light beam (L) onto the fundus (12) via the ellipsoidal mirror (32). T L T The ellipsoidal mirror (32) is used for scanning, having a first focal point (32-1) and a second focal point (32-2), wherein during the use of the ultra-wide field ophthalmic imaging instrument (100; 300), the rotatable mirror (30) is arranged to receive a beam (L) via the first focal point (32-1). T L T The scan is performed, and the pupil (14) of the eye (10) is positioned at the second focal point (32-2); and A fixed target light source (80) is arranged to reflect the fixed light (L) via the rotatable reflector (30) and the ellipsoidal mirror (32). F ) Projected onto the fundus (12), The method includes: Control (S10) to keep the rotatable mirror (30) stationary in a predetermined orientation; When the rotatable mirror (30) is stationary in the predetermined orientation, the fixed target light source (80) is controlled (S20) to direct the fixed light (L) to the fixed target light source (80). F The projected light (L) is projected onto the rotatable mirror (30), and the predetermined orientation causes the fixed light (L) to be projected onto the rotatable mirror (30). F The rotatable mirror (30) is reflected onto the fundus (12) via the ellipsoidal mirror (32) to fix the gaze direction of the eye (10); Control (S30) the light source (20; 20') to emit a beam (L) T L T ');as well as Control (S40) the ultra-wide field ophthalmic imaging instrument (100; 300) to project a beam (L) onto the fundus (12) via the ellipsoidal mirror (32) through the rotatable mirror (30). T L T A scan is performed to obtain the ultrawide field image (55) of the fundus (12).

14. The method of claim 13, wherein: The fixation target light source (80) is operable to direct the fixation light (L) from a selected position among a plurality of positions on the fixation target light source (80). F The projection is onto the rotatable mirror (30), and the plurality of positions are arranged in directions different from the first focal point (39-1). The method further includes: Selecting (S22) a gaze direction from multiple different gaze directions, the gaze direction of the eye (10) will be fixed in the gaze direction; and Using the selected gaze direction to determine (S24) the corresponding position among the plurality of positions, the fixation target light source (80) will project the fixation light (L) from that position. F The projection is onto the rotatable mirror (30). In this process, the fixation target light source (80) is controlled (S26) to direct the fixation light (L) F The eye (10) is projected from the determined position onto the rotatable mirror (30) in the predetermined orientation to fix the gaze direction of the eye (10) in the selected gaze direction.

15. The method according to claim 13 or claim 14, wherein, The ultra-wide field ophthalmic imaging instrument (100; 300) includes an ultra-wide field scanning laser ophthalmoscope.

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