Ophthalmic device

Abstract

An ophthalmic apparatus is provided, comprising a light source (82; 84) arranged to emit a fixation target light, and a reflecting surface (68A) arranged to reflect a scanning light emitted by an emission segment, which is different from a source of the scanning light of the light source, and to scan the scanning light in a certain direction by changing an orientation. The ophthalmic apparatus further comprises a concave mirror surface (70A) arranged such that, when an eye (38) of a subject is brought to a focal point of the concave mirror during use of the ophthalmic apparatus, the scanning light reflected by the reflecting surface (68A) is incident on a fundus of the subject, and arranged such that, when the eye (38) of the subject is brought to the focal point of the concave mirror (70) during use of the ophthalmic apparatus and when the light source (82; 84) emits the fixation target light, the fixation target light and the scanning light are simultaneously incident on the fundus via different optical paths, which both propagate via the concave mirror surface (70A) and the focal point, the fixation target light proceeding along a predetermined optical path for fixation of a gaze of the eye (38) of the subject.

Description

Technical Field

[0001] The technology disclosed herein relates to an ophthalmic device.

[0002] background

[0003] For ease of explanation, in the following text, optical coherence tomography will be referred to as "OCT" and scanning laser ophthalmoscope examination will be referred to as "SLO".

[0004] Patent document 1 describes a fundus examination device equipped with an OCT unit that uses OCT to generate images. In the OCT unit described in patent document 1, a tomographic image is generated based on an image signal detected by a charge-coupled device (CCD), which is an image taken in the thickness direction of the membrane in the subject's fundus.

[0005] A liquid crystal display (LCD) is incorporated in the fundus examination device of Patent Document 1, and when the fundus is imaged by an OCT unit, the LCD displays a fixed target to fix the subject's gaze on a specific orientation. Light from the LCD is incident on the subject's eye through an optical system including lenses and mirrors, so that the fixed target is projected onto the fundus of the subject's eye.

[0006] Related documents

[0007] Relevant patent documents

[0008] Patent Document 1: Japanese Patent Application Delayed Publication No. 2008-289579 Invention Overview

[0010] The present invention provides an ophthalmic device comprising: a light source configured to emit a fixed target light; and a reflective surface configured to reflect scanning light emitted by an emitting segment and to scan the scanning light in a specific direction by changing its orientation, the emitting segment being a source of scanning light distinct from the light source. The ophthalmic device further comprises a concave mirror arranged such that, when a subject's eye is positioned at the focal point of the concave mirror during use of the ophthalmic device, the scanning light reflected by the reflective surface is incident on the subject's fundus, and is configured such that, when the subject's eye is positioned at the focal point of the concave mirror during use of the ophthalmic device and when the light source emits the fixed target light, the fixed target light and the scanning light simultaneously incident on the fundus via different optical paths propagating through the concave mirror and the focal point, the fixed target light proceeding along a predetermined optical path for fixing the subject's gaze.

[0011] According to one embodiment, an ophthalmic device can be configured such that when a subject's eye is positioned at the focal point of a concave mirror during use of the ophthalmic device, and when a fixed target light is emitted from a light source, the fixed target light and the scanning light simultaneously incident on the fundus via different optical paths passing through the reflecting surface, the concave mirror, and the focal point. The ophthalmic device also includes a controller configured to control the emission of the fixed target light from the light source such that the fixed target light proceeds along a predetermined optical path used to fix the gaze of the subject's eye.

[0012] The ophthalmic device according to the above embodiments may further include at least one additional light source arranged such that when the subject's eye is positioned at the focal point of the concave mirror during use of the ophthalmic device, and when each of the at least one additional light source emits a fixed target light, the corresponding fixed target light and scanning light simultaneously incident on the fundus via different optical paths that both proceed through the concave mirror and the focal point, the optical path of the corresponding fixed target light not passing through the reflecting surface. The controller may be configured to select a light source from the light sources and control the emission of the fixed target light by the selected light source based on information indicating at least one of the orientation of the reflecting surface, the orientation range of the reflecting surface, and the rate of change of the orientation of the reflecting surface, such that the fixed target light emitted by the selected light source proceeds along a predetermined optical path for fixing the subject's gaze.

[0013] The ophthalmic device according to the above embodiments may optionally include at least one additional light source configured such that when the subject's eye is positioned at the focal point of the concave mirror during use of the ophthalmic device, and when each of the at least one additional light source emits a fixed target light, the corresponding fixed target light and scanning light simultaneously incident on the fundus via different optical paths that both proceed through the reflecting surface, the concave mirror, and the focal point. The controller may be configured to select a light source from the light sources and control the emission of the fixed target light by the selected light source based on information indicating one of the orientation of the reflecting surface, the range of orientation of the reflecting surface, and the rate of change of orientation of the reflecting surface, such that the fixed target light emitted by the selected light source proceeds along a predetermined optical path used to fix the subject's gaze.

[0014] Any of the ophthalmic devices described above can be configured such that when the subject's eye is positioned at the focal point of the concave mirror during the use of the ophthalmic device, and when each light source emits a fixed target light, the corresponding fixed target light and scanning light are simultaneously incident on different locations of the fundus via different optical paths that both advance through the concave mirror and the focal point.

[0015] In the ophthalmic device according to this embodiment, or in any of the variations thereof described above, the controller may be configured to control the emission of fixed target light by each light source such that the light source emits fixed target light only when the reflective surface is oriented in a predetermined orientation, which is adjustable to change the position on the fundus where the fixed target light is emitted.

[0016] Any of the ophthalmic devices described above may further include a second reflecting surface, which is arranged at a first position separated from the optical path of the scanning light when the scanning light is emitted onto the peripheral region of the fundus. This second reflecting surface may be arranged to reflect a fixed target light onto the fundus along a predetermined optical path via the concave mirror surface when the subject's eye is positioned at the focal point of the concave mirror during use of the ophthalmic device. In this case, the second reflecting surface may be movable between the first and second positions. The second position is separated from the optical path of the scanning light when the scanning light is emitted onto the central region of the fundus. The ophthalmic device may further include a moving mechanism configured to move the second reflecting surface between the first and second positions, and a controller configured to control the moving mechanism and control a light source configured to emit the fixed target light reflected from the second reflecting surface. This is such that the second reflecting surface is arranged at the first position, and the light source is illuminated when the orientation of the first reflecting surface is such that the orientation of the scanning light is such that the scanning light is emitted onto the central region. The second reflecting surface is then arranged at the second position. In the case that the above embodiments include these additional features, the controller can be configured to select the light source in the light source based on information indicating at least one of orientation, the orientation range of the reflective surface, and the speed of orientation change of the reflective surface, control the emission of fixed target light by the selected light source, and control the positioning of the second reflective surface by the moving mechanism, such that the fixed target light emitted by the selected light source travels along a predetermined optical path for fixing the gaze of the subject's eyes.

[0017] Optionally, any of the ophthalmic devices described above may further include a second light source, which is positioned at a first position separate from the optical path of the scanning light when the scanning light is emitted onto the peripheral region of the fundus, and is configured to emit a fixed target light onto the fundus along a predetermined optical path via the concave mirror surface during use of the ophthalmic device when the subject's eye is positioned at the focal point of the concave mirror. In one variation, the second light source may be movable between the first and second positions, with the second position separated from the optical path of the scanning light when the scanning light is emitted onto the central region of the fundus, and the ophthalmic device may further include a moving mechanism and a controller configured to move the second light source between the first and second positions, and the controller configured to control the moving mechanism and the emission of the fixed target light by the second light source, such that the second light source is positioned at the first position and illuminated when the orientation of the first reflective surface is such that the orientation of the first reflective surface is such that the orientation of the scanning light is such that the scanning light is emitted onto the central region, and the second light source is positioned at the second position. When the above-mentioned modifications are applied to the above embodiments, the controller can be configured to select a light source from the light source based on information indicating at least one of orientation, the orientation range of the reflective surface, and the speed of orientation change of the reflective surface, control the emission of the selected light source to the fixed target light, and control the positioning of the moving mechanism to the second light source, such that the fixed target light emitted by the selected light source travels along a predetermined optical path for fixing the gaze of the subject's eyes.

[0018] Any of the ophthalmic devices described above can be configured such that when the subject's eye is at the focal point of the concave mirror during use of the ophthalmic device, the light source is configured to emit a fixed target light, such that the fixed target light incident on the fundus is perceived by the subject as a continuous illumination at one location due to the afterimage effect. Attached Figure Description

[0019] Figure 1 This is a block diagram illustrating an example of the overall configuration of a fundus examination device according to the first to fourth exemplary embodiments.

[0020] Figure 2 This is a schematic perspective view illustrating an example of the configuration of an optical system that guides light emitted from a corresponding light source of an imaging system of a fundus examination apparatus according to the first to fourth exemplary embodiments to the eye of a subject.

[0021] Figure 3 This is a block diagram illustrating an example of the hardware configuration of the main controller included in a fundus examination device according to the first to fourth exemplary embodiments.

[0022] Figure 4This is a conceptual plan view illustrating a schematic configuration of a dichroic mirror, a slit mirror, an H-galvanometer reflector, an ellipsoid mirror, a first fixed target light source, and a second fixed target light source included in a fundus examination device according to a first exemplary embodiment.

[0023] Figure 5 This is a conceptual plan view showing an example of a configuration according to the technology disclosed herein included in a fundus examination device according to a first exemplary embodiment, with the first fixed target light source illuminated.

[0024] Figure 6 This is a conceptual plan view illustrating an example of a configuration according to the technology disclosed herein, in a fundus examination device according to a first exemplary embodiment, with the first and second fixed target light sources included being turned off.

[0025] Figure 7 This is a conceptual plan view illustrating an example of a configuration according to the technology disclosed herein, in the state where the second fixed target light source included in the fundus examination device according to the first exemplary embodiment is illuminated.

[0026] Figure 8 This is a flowchart illustrating an example of the flow of a fixed target light control process according to a first exemplary embodiment.

[0027] Figure 9 This is a conceptual plan view illustrating a schematic configuration of the dichroic mirror, slit mirror, H-galvanometer reflector, ellipsoid mirror, and first to fourth fixed target light sources included in a fundus examination device according to a second exemplary embodiment.

[0028] Figure 10 This is a conceptual plan view illustrating an example of a configuration according to the technology disclosed herein, in a fundus examination device according to a second exemplary embodiment, with the third fixed target light source included being illuminated.

[0029] Figure 11 This is a conceptual plan view illustrating an example of a configuration according to the technology disclosed herein, in the state where the fourth fixed target light source included in the fundus examination device according to the second exemplary embodiment is illuminated.

[0030] Figure 12 This is a flowchart illustrating an example of the flow of a fixed target light control process according to a second exemplary embodiment.

[0031] Figure 13 This is a conceptual plan view illustrating a schematic configuration of a dichroic mirror, a slit mirror, an H-galvanometer reflector, an ellipsoidal mirror, a plane mirror, and a first to third fixed target light source included in a fundus examination device according to a third exemplary embodiment.

[0032] Figure 14 This is a conceptual plan view illustrating an example of a configuration according to the technology disclosed herein at the moment of illumination, in a fundus examination device according to a third exemplary embodiment, where the third fixed target light source emits light onto a third end.

[0033] Figure 15 This is a conceptual plan view showing an example of a configuration according to the technology disclosed herein at the moment of illumination, in a fundus examination device according to a third exemplary embodiment, in which a third fixed target light source emits light onto a fourth end.

[0034] Figure 16 This is a conceptual plan view illustrating an example of a configuration according to the technology disclosed herein, in the state where the third fixed target light source included in the fundus examination device according to the third exemplary embodiment is turned off.

[0035] Figure 17 This is a flowchart illustrating an example of the flow of a fixed target light control process according to a third exemplary embodiment.

[0036] Figure 18 This shows an example fixed constraint diagram used to select a fixed target light source.

[0037] Figure 19 This is a conceptual plan view illustrating an example of a configuration according to the technology disclosed herein at the moment of illumination, in a fundus examination device according to a fourth exemplary embodiment, where the third fixed target light source includes emitting light onto a fourth end.

[0038] Figure 20 This is a flowchart illustrating an example of the flow of a fixed target light control process according to a fourth exemplary embodiment.

[0039] Figure 21 This is a conceptual plan view illustrating a modified example of the configuration of a fundus examination device according to a third exemplary embodiment.

[0040] Figure 22 This is a conceptual plan view illustrating a modified example of the configuration of a fundus examination device according to a fourth exemplary embodiment.

[0041] Figure 23 This is a conceptual diagram illustrating an example of installing a program from a storage medium storing the program into a fundus examination device according to the first to fourth exemplary embodiments.

[0042] Figure 24 It shows the corresponding Figure 1 The diagram shows a conceptual configuration of the SLO unit, OCT unit, and shared optical system.

[0043] Figure 25 This is a conceptual diagram illustrating a first modified example of a scanning optical system.

[0044] Figure 26 This is a conceptual diagram illustrating a second modified example of a scanning optical system.

[0045] Figure 27 This is a conceptual plan view illustrating a modified example of the relevant configuration of a fundus examination device according to a second exemplary embodiment.

[0046] Description of the Implementation Examples

[0047] Referring to the accompanying drawings, examples of exemplary embodiments according to the present invention are explained below.

[0048] Embodiments of the present invention provide a fundus examination device, as an example of an ophthalmic device, which is capable of presenting a fixed target with a wide angle corresponding to a region of the fundus, with light emitted from a light source onto the fundus for fundus imaging.

[0049] The fundus examination device of a first embodiment of the present invention includes a reflective surface that reflects light emitted by an emitting segment for imaging the fundus of a subject's eye and scans the light in a specific direction by changing its orientation; a concave mirror arranged such that light reflected by the reflective surface is incident on the fundus and such that the focal point of the light reflected by the reflective surface is located at the subject's eye; and a plurality of light sources that emit fixed target light as an indicator of a fixed target in a fundus-facing state via the reflective surface and the mirror, the plurality of light sources including: a first light source that illuminates in a first orientation in which the reflective surface is oriented such that light is emitted onto a first end, the first end being an end in a specific direction in the central region of the fundus; and a second light source that illuminates in a second orientation in which the reflective surface is oriented such that light is emitted onto a second end, the second end being another end in a specific direction in the central region. Therefore, the fundus examination device enables the presentation of a fixed target corresponding to a widened angle in the region of the fundus, with light emitted from the light source onto the fundus for fundus imaging.

[0050] In the fundus examination device of the first embodiment, when light is scanned back and forth in a specific direction in the central region to pass through the first and second ends, the rate of change of orientation of the reflective surface can be no less than the rate at which the illumination of the first and second light sources is perceived by the subject as continuous illumination due to the afterimage effect. Therefore, the fundus examination device according to the second aspect of the invention enables the subject to see a fixed target without interruption when light emitted from the light source for imaging the fundus is emitted onto the central region of the fundus and imaged.

[0051] In any variation of the fundus examination device described above, the multiple light sources may further include: a third light source that illuminates with the reflective surface oriented in a third orientation such that light is emitted onto a third end, which is an end in a specific direction in the peripheral region of the central region; and a fourth light source that illuminates with the reflective surface oriented in a fourth orientation such that light is emitted onto a fourth end, which is another end in a specific direction in the peripheral region. Therefore, the fundus examination device makes it possible to visualize a fixed target corresponding to the peripheral region of the central region of the fundus.

[0052] Furthermore, in this variation of the fundus examination device, the speed at which the orientation of the reflective surface changes when light is scanned back and forth in a specific direction across the central and peripheral regions to pass through the third and fourth ends can be no less than the speed at which the illumination of the third and fourth light sources is perceived by the subject as continuous illumination due to the afterimage effect. Therefore, when light emitted from the light source used for fundus imaging is projected onto the peripheral region of the central region of the fundus and imaged, the fundus examination device allows the subject to see a fixed target without interruption.

[0053] The fundus examination device according to a second embodiment of the present invention includes: a first reflective surface that reflects light emitted by an emitting segment for imaging the fundus of a subject's eye and scanning light in a specific direction by changing its orientation; a concave mirror arranged such that light reflected by the first reflective surface is incident on the fundus and such that the focal point of the light reflected by the first reflective surface is located at the subject's eye; a light source arranged at a position separate from the light's optical path and emitting a fixed target light, the fixed target light being a light indicating a fixed target; and a second reflective surface arranged at a position separate from the light's optical path in the case where light is emitted onto a peripheral region of the central region of the fundus, in a first position. The device includes a mirror that reflects a fixed target light emitted from a light source and is capable of emitting the reflected fixed target light via a mirror in a state facing the fundus; a moving mechanism that, by receiving a driving force from a driving source, moves a second reflecting surface between a first position and a second position separated from the light path when light is emitted onto a central region; and a controller configured to control the driving source and the light source such that the second reflecting surface is positioned at the first position and the light source is illuminated when the orientation of the first reflecting surface is such that light is emitted onto a peripheral region, and that the second reflecting surface is positioned at the second position and the light source is illuminated when the orientation of the first reflecting surface is such that light is emitted onto a central region. Therefore, the fundus examination device according to the second embodiment of the invention enables the presentation of a fixed target at a widened angle corresponding to a region of the fundus, with light emitted from the light source onto the fundus for fundus imaging.

[0054] The fundus examination device according to a third embodiment of the present invention includes: a first reflective surface that reflects light emitted by an emitting segment for imaging the fundus of a subject's eye, and scans light in a specific direction by changing its orientation; a concave mirror arranged such that light reflected by the first reflective surface is incident on the fundus, and such that the focal point of the light reflected by the first reflective surface is located at the subject's eye; and a light source arranged at a position separate from the light path in the case where light is emitted onto the peripheral region of the central region of the fundus, and is capable of emitting light in a fixed position facing the fundus via the mirror. The device comprises: a target light, wherein the fixed target light is light indicating a fixed target; a moving mechanism that moves the light source between a first position and a second position separated from the optical path of the light when the light is emitted onto a central region by receiving a driving force from a driving source; and a controller configured to control the driving source and the light source such that the light source is illuminated at the first position and the orientation of the first reflecting surface is such that the light is emitted onto a peripheral region of the central region of the fundus, and that the light source is illuminated at the second position and the orientation of the first reflecting surface is such that the light is emitted onto the central region. Therefore, the fundus examination device according to the third embodiment of the invention enables the presentation of a fixed target at a widened angle corresponding to a region of the fundus, with light emitted from the light source onto the fundus for fundus imaging.

[0055] The fundus examination device according to a fourth embodiment of the present invention includes: a concave mirror arranged such that light reflected by a reflective portion of light emitted for imaging the fundus of a subject's eye is incident on the fundus, and such that the focal point of the light is located at the subject's eye; a light source arranged at a position separated from the optical path of the light in the peripheral region of the central region of the fundus, and emitting a fixed target light, the fixed target light being a light indicating a fixed target; a reflective surface arranged at a position separated from the optical path of the light in the peripheral region of the central region of the fundus, reflecting the fixed target light emitted from the light source at a first position, and capable of emitting the reflected fixed target light via the mirror in a state facing the fundus; and a moving mechanism that moves the reflective surface between a first position and a second position separated from the optical path of the light in the case of light being emitted onto the central region. Therefore, the fundus examination device according to the fourth embodiment of the present invention enables the presentation of a fixed target at a widened angle corresponding to a region of the fundus, with light emitted from the light source onto the fundus for imaging the fundus.

[0056] A fundus examination device according to a fifth embodiment of the present invention includes: a concave mirror arranged such that light reflected by a reflective portion of light emitted for imaging the fundus of a subject's eye is incident on the fundus, and such that the focal point of the light is located at the subject's eye; a light source arranged at a position separated from the optical path of the light, and capable of emitting a fixed target light, which is a light indicating a fixed target, via the mirror in a fundus-facing state in a first position; and a moving mechanism that moves the light source between a first position and a second position separated from the optical path of the light when the light is emitted onto a central region. Therefore, the fundus examination device according to the fifth embodiment of the present invention enables the presentation of a fixed target at a widened angle corresponding to a region of the fundus, with light emitted from the light source onto the fundus for fundus imaging.

[0057] Exemplary embodiments of the present invention have the advantageous effect of enabling a fixed target to be presented at a widened angle corresponding to the region of the fundus, with light emitted from a light source onto the fundus for fundus imaging.

[0058] In the following exemplary embodiments, "perpendicular" means perpendicular to the meaning of an error contained within the acceptable range, and "parallel" means parallel to the meaning of an error contained within the acceptable range. Furthermore, in the exemplary embodiments, "facing" means facing the meaning of an error contained within the acceptable range. Additionally, "same" means the same as the meaning of an error contained within the acceptable range.

[0059] In the exemplary embodiment, for ease of explanation, a superluminescent diode is referred to as "SLD". Also, for ease of explanation, an interface is referred to as "I / F". Furthermore, red is referred to as "R" and green as "G".

[0060] First exemplary embodiment

[0061] like Figure 1 As shown, as an example of an ophthalmic device according to an embodiment of the present invention, the fundus examination device 10A includes a device body 12 and a controller 13.

[0062] The main body of the device 12 includes an SLO unit 32, an OCT unit 34, and a shared optical system 36. Note that the SLO unit 32 and the OCT unit 34 are examples of a "transmit segment" according to the technology disclosed herein.

[0063] The fundus examination device 10A includes SLO imaging system functionality and OCT imaging system functionality. The SLO imaging system functionality is used for imaging using SLO, and the OCT imaging system functionality is used for imaging using OCT. The SLO imaging system functionality is implemented by controller 13, SLO unit 32, and shared optical system 36. The OCT imaging system functionality is implemented by controller 13, OCT unit 34, and shared optical system 36.

[0064] The fundus examination device 10A includes SLO mode and OCT mode. SLO mode is the operating mode that utilizes the SLO imaging system functions, and OCT mode is the operating mode that utilizes the OCT imaging system functions. SLO mode and OCT mode can be selectively set according to user commands or sequential control.

[0065] SLO unit 32 includes a transmitter 40, a beam splitter 42, a polygon mirror 44, a photodetector 46, and a motor 48 used to generate a two-dimensional image of the surface of the fundus of the subject's eye 38.

[0066] For ease of explanation, the fundus of the subject's eye 38 will be simply referred to as "fundus" in the following text. Furthermore, in the case where, for example, the fundus examination device 10A is mounted on a horizontal plane, for ease of explanation, the direction perpendicular to the horizontal plane (not shown in the figure) will be referred to as the "Y direction". Additionally, for example, when the fundus examination device 10A is mounted on a horizontal plane, the direction parallel to the horizontal plane and positioned as the depth direction of the subject's eye 38 in a state where the eyepiece lens (not shown in the figure) faces the fundus examination device 10A at its anterior end will be referred to as the "Z direction" in the following text for ease of explanation. Hereinafter, for ease of explanation, the direction perpendicular to both the Y and Z directions will be referred to as the "X direction".

[0067] The transmitting section 40 includes a light source 40A and a bandpass filter 40B. The light source 40A is a light source for imaging using SLO and emits light with wavelengths ranging from about 400 nanometers to about 900 nanometers. The light emitted from the light source 40A passes through the bandpass filter 40B, such that only light with specific wavelengths is emitted onto the beam splitter 42.

[0068] In this first exemplary embodiment, the light emitted from the emitting segment 40 is broadly divided into visible light (RG light) and near-infrared light, wherein the near-infrared light is light having a wavelength in the near-infrared region.

[0069] In this first exemplary embodiment, RG light and near-infrared light are selectively emitted from the emission section 40 by changing the wavelength of the light generated by the light source 40A and by applying a bandpass filter 40B to the light generated by the light source 40A.

[0070] For ease of explanation, where it is not necessary to distinguish between RG light and near-infrared light, the RG light and near-infrared light used as light emitted from the emission section 40 will be simply referred to as "SLO light" below. Furthermore, SLO light is an example of "light for imaging the fundus of a subject's eye" (also referred to as "scanning light") according to the technology disclosed herein.

[0071] Beam splitter 42 guides the SLO light to polygon mirror 44 by transmitting SLO light and guides the first fundus reflected light to photodetector 46. Here, the first fundus reflected light refers to the light originating from the SLO light and reflected by the fundus. The light reflected by the fundus refers to the light reflected by the fundus and then incident on the shared optical system 36.

[0072] The polygon mirror 44 transmits the SLO light from the beam splitter 42 to the shared optical system 36. Then, as in Figure 2 As shown as an example, the polygon mirror 44 scans the SLO light in the Y direction by rotating in the direction of arrow A when it receives the driving force of the motor 48.

[0073] The photodetector 46 includes a photodetector 46A and a filter 46B. The filter 46B is positioned between the light-receiving surface 46A1 of the photodetector 46A and the reflective surface 42A of the beam splitter 42, and covers the light-receiving surface 46A1. First fundus reflected light composed of near-infrared light and first fundus reflected light composed of RG light are selectively incident on the light-receiving surface 46A1.

[0074] The photodetector 46A generates an SLO image signal—which is an image signal based on the first fundus reflected light incident through the filter 46B—and outputs the generated SLO image signal.

[0075] OCT unit 34 is used to generate tomographic images of the fundus and includes SLD 50, optical coupler 52, reference light optical system 54, spectrophotometer 56, line sensor 58, V-galvanometer reflector 60 and motor 62.

[0076] SLD 50 emits low-coherence light. For example, low-coherence light means light in the near-infrared region that has a longer wavelength than the near-infrared light emitted from emission section 40 and has a time coherence length of about tens of micrometers.

[0077] Low-coherence light emitted from SLD 50 is fed into optical coupler 52 via a first optical fiber (not shown in the figure) and split into reference light and signal light. The reference light is guided to reference light optics 54 via a second optical fiber (not shown in the figure), and the signal light is guided to V-galvanometer mirror 60 via a third optical fiber (not shown in the figure). Note that the signal light is an example of "light for imaging the fundus of a subject's eye" (also referred to as "scanning light") according to the technology disclosed herein.

[0078] The reference light optical system 54 includes a collimating lens (not shown in the figure), a dispersion-compensating glass (not shown in the figure), and a reference mirror (not shown in the figure). The reference light is guided to the reference mirror through the collimating lens and the dispersion-compensating glass.

[0079] The reference mirror returns the reference light to the optical coupler 52 by reflecting the reference light through the same optical path. The reference mirror is a movable mirror capable of moving along the optical axis of the reference light, and the length of the optical path of the reference light is adjusted by moving the position of the reference mirror along the optical axis. Images of the fundus at different locations in the Z-direction can be acquired by moving the reference mirror.

[0080] V-galvanometer reflector 60 sends signal light to shared optical system 36. Then, as in Figure 2 As shown in the example, when the driving force of the motor 62 is received, the V-galvanometer reflector 60 scans the signal light in the Y direction by rotating and oscillating in the direction of arrow B.

[0081] Furthermore, the V-galvanometer reflector 60 guides the second fundus reflected light to the optical coupler 52 via a fourth optical fiber. Here, the second fundus reflected light refers to the light reflected from the fundus originating from the signal light.

[0082] The second fundus reflected light guided by optical coupler 52 is superimposed with the reference light guided from the reference light optical system to optical coupler 52 by optical coupler 52, and interference occurs. The interference light obtained due to the interference is spectrally dispersed by spectrophotometer 56, and the spectrally dispersed interference light is guided to line sensor 58.

[0083] The line sensor 58 generates an OCT image signal (which is an image signal based on incident interference light) and outputs the generated OCT image signal.

[0084] The shared optical system 36 includes a dichroic mirror 64, a slit mirror 66 with an elliptical concave reflective surface, an H-galvanometer reflector 68, an ellipsoidal mirror 70, and a motor 72.

[0085] The dichroic mirror 64 guides the SLO light to the slit mirror 66 by transmitting the SLO light from the polygon mirror 44 of the SLO unit 32, and guides the signal light to the slit mirror 66 by reflecting the signal light from the V-galvanometer reflector 60 of the OCT unit 34.

[0086] For ease of explanation, unless it is necessary to distinguish between signal light and SLO light, signal light and SLO light will be referred to as “emission light” or “scanning light” in the following text.

[0087] The slit mirror 66 reflects the incident emitted light toward the H-galvanometer reflector 68. The H-galvanometer reflector 68 reflects the emitted light from the slit mirror 66 and sends it to the mirror 70A of the ellipsoidal mirror 70. Then, as in Figure 2 As shown in the example, when receiving a driving force from motor 48, the H-galvanometer reflector 68 scans the emitted light in the X direction by rotating and oscillating in the direction of arrow C. Note that, according to the technology disclosed herein, the X direction is an example of a "specific direction". Mirror 70A is an example of a "concave mirror" according to the technology disclosed herein.

[0088] The ellipsoid 70 guides emitted light to the fundus by reflecting emitted light incident on the mirror 70A. The ellipsoid 70 is arranged such that the focal point of the emitted light reflected by the mirror 70A is located at the subject's eye 38. In other words, the ellipsoid 70 is arranged such that its focal point is located at the pupil of the subject's eye 38 during use of the fundus examination device 10A. The emitted light guided to the fundus by the ellipsoid 70 is reflected by the fundus. The reflected light is then guided along the same optical path as the emitted light to the dichroic mirror 64 in the shared optics system 36. The dichroic mirror 64 guides the first fundus reflected light to the SLO unit 32 and the second fundus reflected light to the OCT unit 34. The basic configuration of the fundus imaging optical system, formed by two elliptical surfaces, is similar to that described in PCT application No. PCT / GB94 / 02465 (WO 95 / 13012) and PCT / GB2007 / 002208 (WO2008 / 009877), the disclosures of which are incorporated herein by reference. Furthermore, the embodiments described herein can be structurally and operationally combined with, for example, related systems and methods disclosed in US 7,959,290, US 2015 / 0216408, US 2014 / 0327882, US 2013 / 0135583, and US 2013 / 0335703, the disclosures of which are also incorporated herein by reference.

[0089] In the fundus examination device 10A, such as in Figure 1As an example, the area of ​​the fundus to which the emitted light is emitted is broadly divided, according to the technique disclosed herein, into a first emitted region α, exemplified as a "central region of the fundus," and a second emitted region β, exemplified as a "peripheral region." When the emitted light is incident on the eye 38 at an angle greater than ±30 degrees, it can illuminate the periphery of the retina.

[0090] The first emitted region α represents, for example, an angular range of 45° on the Z-direction side surrounding the center O of the subject's eye 38; in other words, an area extending 45° from the center of the fundus along the circumferential direction of the fundus, with the center O of the subject's eye 38 as a reference point. The second emitted region β represents, for example, an angular range greater than 45° but not greater than 200° on the Z-direction side surrounding the center O of the subject's eye 38; in other words, an area extending 45° but not greater than 200° from the center of the fundus along the circumferential direction of the fundus, with reference to the center O of the subject's eye 38.

[0091] The controller 13 controls the operation of the device body 12 by exchanging various information with the device body 12. Furthermore, the controller 13 generates a two-dimensional image indicating one aspect of the fundus surface based on the SLO image signal obtained from the photodetector 46A. The controller 13 also generates a tomographic image of the fundus based on the OCT image signal obtained from the line sensor 58.

[0092] Note that in this first exemplary embodiment, the two-dimensional image obtained using the SLO unit 32 is broadly divided into a chromatic aberration image based on RG light and a chromatic aberration image based on near-infrared light. Furthermore, the tomographic image obtained using the OCT unit 34 is a chromatic aberration image. The two-dimensional image obtained using the SLO unit 32 and the tomographic image obtained using the OCT unit 34 can be displayed as still images or as real-time view images.

[0093] The controller 13 includes a main controller 14, an OCT image generator 16, an SLO image generator 18, a receiving I / F 20, a receiving device 22, a display controller 24, a display 26, a communication I / F 28, and a bus 30.

[0094] The main controller 14, OCT image generator 16, SLO image generator 18, receiver I / F 20, display controller 24, and communication I / F 28 are connected to each other via bus 30. Therefore, the main controller 14 can exchange various information items with the OCT image generator 16, SLO image generator 18, receiver I / F 20, display controller 24, and communication I / F 28.

[0095] The main controller 14 controls the driving of motors 48, 62, and 72 by controlling the corresponding motor drive circuits (not shown in the figure) of motors 48, 62, and 72 via communication I / F 28.

[0096] Furthermore, the main controller 14 controls the light source driving circuit (not shown in the figure) corresponding to the light source 40A via the communication I / F 28 to switch between turning the light source 40A on and off, adjust the amount of light, change the wavelength of the light generated by the light source 40A, and so on.

[0097] Furthermore, the main controller 14 controls the SLD drive circuit (not shown in the figure) corresponding to the SLD 50 via the communication I / F 28 to switch between turning the SLD 50 on and off, adjust the amount of light, change the wavelength of the light generated by the SLD 50, and so on.

[0098] In addition, the main controller 14 controls the operation of the bandpass filter 40B, the filter 46B, and the reference mirror of the reference optical system 54 via the communication I / F 28.

[0099] The receiving device 22 includes a keyboard, mouse, touchpad, etc., and receives various commands from the user.

[0100] The receiving device 22 is connected to the receiving I / F 20 and outputs an instruction content signal indicating the content of the received instruction to the receiving I / F 20. The main controller 14 performs processing based on the instruction content signal input from the receiving I / F 20.

[0101] Display 26 is, for example, an LCD or an organic electroluminescent display (OELD). Display 26 is connected to display controller 24. Under the control of main controller 14, display controller 24 controls display 26 to display two-dimensional images obtained using SLO unit 32 and tomographic images obtained using OCT unit 34, as still images or real-time view images. Under the control of main controller 14, display controller 24 also controls display 26 to display various screens, such as menu screens.

[0102] The communication I / F 28 is connected to the electrical system of the device body 34 and operates under the control of the main controller 14 to manage the exchange of various information between the main controller 14 and the device body 34.

[0103] SLO image generator 18 acquires SLO image signals from photodetector 46A of SLO unit 32 via communication I / F 28, and SLO image generator 18 is a dedicated circuit that performs processing to generate a two-dimensional image based on the acquired SLO image signals.

[0104] For example, the SLO image generator 18 outputs each frame of the generated two-dimensional image to the display controller 24 at a specific frame rate of tens of frames per second. The display controller 24 displays the two-dimensional image input from the SLO image generator 18 as a real-time view image on the display 26 according to instructions from the main controller 14. Furthermore, according to instructions from the main controller 14, the display controller 24 displays the two-dimensional image input from the SLO image generator 18 as a still image on the display 26.

[0105] OCT image generator 16 acquires OCT image signals from line sensor 58 of OCT unit 34 via communication I / F 28, and OCT image generator 16 is a dedicated circuit that performs processing to generate tomographic images based on the acquired OCT image signals.

[0106] For example, the OCT image generator 16 outputs each frame of the generated tomographic image to the display controller 24 at a specific frame rate of tens of frames per second. The display controller 24 displays the tomographic image input from the OCT image generator 16 as a real-time view image on the display 26 according to instructions from the main controller 14. Furthermore, according to instructions from the main controller 14, the display controller 24 displays the tomographic image input from the OCT image generator 16 as a still image on the display 26.

[0107] Note that in this first exemplary embodiment, an example is given in which the OCT image generator 16 and the SLO image generator 18 are each implemented using a field-programmable gate array (FPGA); however, the techniques disclosed herein are not limited thereto. For example, the OCT image generator 16 and the SLO image generator 18 can each be implemented using a computer including a CPU, ROM, and RAM, or they can be implemented using an application-specific integrated circuit (ASIC). Furthermore, the OCT image generator 16 and the SLO image generator 18 can each be implemented using a combination of hardware and software configurations.

[0108] As in Figure 3 As shown as an example, the main controller 14 includes a central processing unit (CPU) 74, a main memory segment 76, and an auxiliary memory segment 78. The CPU 74, the main memory segment 76, and the auxiliary memory segment 78 are interconnected via a bus 30.

[0109] The CPU 74 (which is an example of a "controller" according to the technology disclosed herein) generally controls the fundus examination device 10A. The main memory segment 76 is volatile memory used as a working area, etc., when executing various programs. Examples of the main memory segment 76 include random access memory (RAM). The auxiliary memory segment 78 is non-volatile memory storing programs, various parameters, etc., used to control the basic operations of the fundus examination device 10A. Examples of the auxiliary memory segment 78 include electrically erasable programmable read-only memory (EEPROM) or flash memory.

[0110] The auxiliary storage segment 78 stores the fixed target light control processing described later by CPU 74 (see [link to CPU 74]). Figure 8 ) program 80A.

[0111] CPU 74 operates as a controller by reading program 80A from auxiliary storage segment 78, extending program 80A into main storage segment 76, and executing program 80A, according to the techniques disclosed herein.

[0112] As in Figure 4 As shown as an example, a first fixed target light source 82, serving as an example of a "first light source" according to the technology disclosed herein, and a second fixed target light source 84, serving as an example of a "second light source" according to the technology disclosed herein, are adjacent to a slit mirror 66. The first fixed target light source 82 is fixed to the housing (not shown in the figure) by a frame 86, etc., and the second fixed target light source 84 is fixed to the housing by a frame 88, etc.

[0113] Here, both the first fixed target light source 82 and the second fixed target light source 84 are light-emitting diodes (LEDs) that emit fixed target light with the same optical characteristics (such as the amount of light, wavelength, and beam diameter), and both are selectively lit and extinguished under the control of the controller 13. Note that the fixed target light refers to the light that indicates a fixed target presented to the subject's eye 38, used to fix the subject's gaze at a specific location when the fundus is imaged in SLO mode and in OCT mode. The fixed target is thus perceived by the subject as being at a fixed location, and is therefore used to fix the subject's gaze in a specific direction.

[0114] In this first exemplary embodiment, the fixed target light is broadly divided into a first fixed target light emitted from a first fixed target light source 82 and a second fixed target light emitted from a second fixed target light source 84. Note that, for ease of explanation in this first exemplary embodiment, without distinguishing between the first and second fixed target lights, the first and second fixed target lights are simply referred to as "fixed target light." Figures 4 to 7In this context, the light path indicated by a single-dotted line is the path of the emitted light (or "scanning light"), and the light path of the fixed target light is indicated by a double-dotted line. As will be explained below, the fundus examination device 10A is arranged such that when the subject's eye 38 is positioned at the focal point of the concave mirror 70 during use of the fundus examination device 10A and when either of the fixed target light sources 82 and 84 emits the fixed target light, the fixed target light and the scanning light are simultaneously incident on the fundus via different light paths, both propagating through the concave mirror 70A and the focal point (e.g., at different locations), with the fixed target light traveling along a predetermined light path used to fix the subject's eye 38.

[0115] As in Figures 5 to 7 As an example, when the signal light is emitted back and forth between the first end α1 and the second end α2, the revolutions per second (i.e., the oscillation frequency of the H-galvanometer mirror 68) of the H-galvanometer mirror 68 is, for example, 25 Hz (Hertz). Note that here, the first end α1 refers to one end of the first region α to which the light is emitted in the X direction, and the second end α2 refers to the other end of the first region α to which the light is emitted in the X direction.

[0116] As in Figure 5 As shown as an example, the first fixed target light source 82 is arranged such that, with the orientation of the mirror 68A of the H-galvanometer reflector 68 being a first orientation, the first fixed target light is emitted onto the central portion (e.g., the fovea of ​​the retina) of the first emitted region α in the fundus-facing state. Note that, according to the technology disclosed herein, the mirror 68A of the H-galvanometer reflector 68 is an example of a "reflecting surface" and a "first reflecting surface".

[0117] The first fixed target light source 82 is illuminated only when the orientation of mirror 68A is the first orientation. Therefore, the first fixed target light source 82 is illuminated when the orientation of mirror 68A is the first orientation, and is not illuminated when mirror 68A is in any other orientation. Note that here, as an example, the first orientation refers to the orientation of mirror 68A when the emitted light is emitted onto the first end α1, such as in... Figure 5 As shown in the example, the first fixed target light source 82 can be illuminated more generally only when the mirror 68A is oriented in a predetermined orientation, which is adjustable to change the position on the fundus where the fixed target light is emitted.

[0118] When the orientation of mirror 68A is the first orientation, the first fixed target light is emitted via mirrors 68A and 70A in a fundus-facing state onto the central portion of the first emitted region α (e.g., the fovea of ​​the retina). That is, when the orientation of mirror 68A is the first orientation, the first fixed target light is reflected by mirror 68A, the reflected first fixed target light is further reflected by mirror 70A, and the first fixed target light reflected by mirror 70A reaches the central portion of the first emitted region α in a fundus-facing state.

[0119] As in Figure 7 As an example, the second fixed target light source 84 is arranged such that, when the orientation of the mirror 68A is the second orientation, the second fixed target light is emitted onto the central portion of the first emitted region α in a state facing the fundus. The second fixed target light source 84 is illuminated only when the orientation of the mirror 68A is the second orientation. Therefore, the second fixed target light source 84 is illuminated when the orientation of the mirror 68A is the second orientation, and is not illuminated when the mirror 68A is in any orientation other than the second orientation. Note that here, as an example, the second orientation refers to the orientation of the mirror 68A when the emitted light is emitted onto the second end α2, as in... Figure 7 As shown in the example, the second fixed target light source 84 can be illuminated more generally only when the mirror 68A is oriented in a predetermined orientation, which is adjustable to change the position on the fundus where the fixed target light is emitted.

[0120] When the orientation of mirror 68A is the second orientation, the second fixed target light, in the state facing the fundus, is emitted via mirror 68A and mirror 70A to the central portion of the first emitted region α. ​​That is, when the orientation of mirror 68A is the second orientation, the second fixed target light is reflected by mirror 68A, the reflected second fixed target light is further reflected by mirror 70A, and the second fixed target light reflected by mirror 70A reaches the central portion of the first emitted region α in the state facing the fundus.

[0121] As in Figure 6 As an example, when the orientation of mirror 68A is neither the first nor the second orientation, that is, when the emitted light is not emitted onto the first end α1 or the second end α2, the first fixed target light source 82 and the second fixed target light source 84 are extinguished. Note that in Figure 6 In the example shown, the signal light (scanning light) is shown in a state where it is emitted onto the central portion of the first emitted region α.

[0122] Note that in this first exemplary embodiment, as described above, because the H-galvanometer reflector 68 operates rotating at 25 Hz, the illumination of the first fixed target light source 82 and the second fixed target light source 84, due to the afterimage effect, is perceived by the subject's eye 38 as continuous illumination. Therefore, although this first exemplary embodiment provides an example of the H-galvanometer reflector 68 operating rotating at 25 Hz in OCT mode, the technology disclosed herein is not limited thereto. For example, the rate of orientation change of the H-galvanometer reflector 68 is sufficient to cause the illumination of the first fixed target light source 82 and the second fixed target light source 84 to be perceived by the subject's eye 38 as continuous illumination due to the afterimage effect. However, regardless of the rate at which the orientation of the H-galvanometer reflector 68 changes, both the first fixed target light source 82 and the second fixed target light source 84 are controlled by the CPU 74 to illuminate the corresponding first and second fixed target lights only at the first and second orientations of the H-galvanometer reflector 68, respectively, and to project the first and second fixed target lights onto the subject's fundus, so that the subject perceives the fixed target as fixed in one position. The fixed target may appear to flash or be continuously illuminated to the subject (depending on the rate at which the orientation of the H-galvanometer reflector 68 changes), but in both cases, it will appear fixed.

[0123] Next, refer to Figure 8 The following is an explanation of the fixed target light control processing performed by the CPU 74 after procedure 80A in the case of fundus imaging in OCT mode (operation as part of the fundus examination device 10A according to the technology disclosed herein).

[0124] exist Figure 8 In the fixed target light control process shown, in step 100, the CPU 74 determines whether the position of the signal light emitted on the fundus is the first end α1. If, in step 100, the position of the signal light emitted on the fundus is the first end α1, a positive determination is made, and the process transitions to step 102. If, in step 100, the position of the signal light emitted on the fundus is not the first end α1, a negative determination is made, and the process transitions to step 106.

[0125] In step 102, the CPU 74 illuminates the first fixed target light source 82 for a given amount of time, and then transitions to step 104. Note that in step 102, the given amount of time refers to the minimum amount of time required to illuminate the first fixed target light source 82. The minimum amount of time required to illuminate the first fixed target light source 82 is sufficient to allow a subject to perceive the first fixed target light source 82 through their eyes 38, based on the results of tests using real equipment or computer simulations, etc.

[0126] In step 106, CPU 74 determines whether the position on the fundus where the signal light is emitted is the second end α2. If in step 106 the position on the fundus where the signal light is emitted is the second end α2, a positive determination is made, and the process transitions to step 108. If in step 106 the position on the fundus where the signal light is emitted is not the second end α2, a negative determination is made, and the process transitions to step 104.

[0127] In step 106, the CPU 74 illuminates the second fixed target light source 84 for a given amount of time (e.g., the same amount of time as the illumination time of the first fixed target light source 82), and then the process transitions to step 104. Note that in the current step 106, the given amount of time refers to the minimum amount of time required to illuminate the second fixed target light source 84. The minimum amount of time required to illuminate the second fixed target light source 84 is sufficient to allow a subject to perceive the second fixed target light source 84 through their eyes 38 based on the results of tests using real equipment or computer simulations, etc.

[0128] In step 104, CPU 74 determines whether the conditions for terminating the fixed target light control process have been met. Note that, for ease of explanation, the conditions for terminating the fixed target light control process will henceforth be simply referred to as the "termination condition".

[0129] Examples of termination conditions here include: the condition that the receiving device 22 has received an instruction to terminate the fixed target light control processing or an instruction to terminate the OCT mode, and the condition that the acquisition of tomographic images with a specified range has been terminated in the OCT mode.

[0130] In step 104, if the termination condition is not met, a negative determination is made, and the process transitions to step 100. In step 104, if the termination condition is met, a positive determination is made, and the current fixed target light control process ends.

[0131] As explained above, the fundus examination device 10A includes a first fixed target light source 82 that illuminates when the orientation of the mirror 68A is a first orientation, and a second fixed target light source 84 that illuminates when the orientation of the mirror 68A is a second orientation. More specifically, the first fixed target light source 82 is illuminated for a predetermined amount of time (e.g., a minimum amount of time required to illuminate the first fixed target light source 82, which is determined, for example, by testing using a real device or computer simulation, etc.) only when the orientation of the mirror 68A is the second orientation, and the second fixed target light source 84 is illuminated for a predetermined amount of time only when the orientation of the mirror 68A is the second orientation. Therefore, according to the fundus examination device 10A, the presentation of a fixed target corresponding to a first emitted region α can be achieved.

[0132] Furthermore, in the fundus examination device 10A, the rate of orientation change of the mirror 68A is such that the subject perceives the illumination of the first fixed target light source 82 and the second fixed target light source 84 as continuous illumination through the subject's eye 38 due to the afterimage effect. Therefore, according to the fundus examination device 10A, when emitted light (signal light, as an example here) is emitted onto the first emission region α to capture an image, the fixed target can be seen by the subject at a fixed position without interruption.

[0133] Second exemplary embodiment

[0134] In the first exemplary embodiment described above, an example is given of using two fixed target light sources (first fixed target light source 82 and second fixed target light source 84) to present a fixed target to a subject. However, the number of fixed target light sources is not limited to two, and a single fixed target light source or more than two fixed target light sources may be provided alternatively. In all cases, the source (multiple sources) of the fixed target light differs from the source (multiple sources) of the scanning light, namely, the SOL unit 32 and the OCT unit 34 in this embodiment. In this second exemplary embodiment, an explanation follows regarding the case of using four fixed target light sources to present a fixed target to a subject.

[0135] Note that in this second exemplary embodiment, the same reference numerals are assigned to the same configuration elements as those explained in the first exemplary embodiment described above, and their explanations are omitted. The explanations focus primarily on the parts that differ from the first exemplary embodiment described above.

[0136] According to the second exemplary embodiment of the present invention, the fundus examination device 10B (see...) Figure 1 The difference between the fundus examination device 10B and the fundus examination device 10A explained in the first exemplary embodiment above is that the fundus examination device 10B includes a third fixed target light source 120, a fourth fixed target light source 122, and frames 124 and 126, as shown in... Figure 9 The example shown is in the middle.

[0137] Furthermore, the difference between fundus examination device 10B and fundus examination device 10A lies in that, for example, in Figure 3 As an example, the second storage segment 78 stores program 80B instead of program 80A.

[0138] The third fixed target light source 120 is an example of a "third light source" according to the technology disclosed herein, and the fourth fixed target light source 122 is an example of a "fourth light source" according to the technology disclosed herein.

[0139] As in Figure 9 As an example, the third fixed target light source 120 and the fourth fixed target light source 122 are arranged at both ends of the slit mirror 66 facing each other in the Z direction, and the fourth fixed target light source 122 is arranged further away from the mirror surface 70A than the third fixed target light source 120.

[0140] The third fixed target light source 120 is arranged adjacent to the first fixed target light source 82, and is positioned further away from the mirror 70A in the Z direction than the first fixed target light source 82. Furthermore, the third fixed target light source 120 is fixed to the housing via a frame 124, etc.

[0141] The fourth fixed target light source 122 is arranged adjacent to the second fixed target light source 84, and is positioned closer to the mirror 70A in the Z direction than the second fixed target light source 84. Furthermore, the fourth fixed target light source 122 is fixed to the housing via a frame 126, etc.

[0142] Here, both the third fixed target light source 120 and the fourth fixed target light source 122 are LEDs, emitting fixed target light with the same optical characteristics (such as the amount of light, wavelength, and beam diameter) as the first fixed target light source 82 and the second fixed target light source 84. Furthermore, under the control of the controller 13, both the third fixed target light source 124 and the fourth fixed target light source 122 are selectively turned on and off.

[0143] In this second exemplary embodiment, the fixed target light is broadly divided into a first fixed target light, a second fixed target light, a third fixed target light emitted from the third fixed target light source 120, and a fourth fixed target light emitted from the fourth fixed target light source 122. Note that, for ease of explanation in this second exemplary embodiment, the first to fourth fixed target lights are simply referred to as "fixed target light" unless the distinction between the first to fourth fixed target lights is made. Furthermore, in Figures 9 to 11 In the diagram, the light path indicated by a single-dotted line is the light path of the emitted light, while the light path of the fixed target light is indicated by a double-dotted line.

[0144] As in Figure 10 and Figure 11 As an example, when the signal light is emitted back and forth between the third end β1 and the fourth end β2, the oscillation frequency of the H-galvanometer reflector 68 is, for example, 25 Hz (Hertz). Note that here, as an example, the third end β1 refers to one of the outermost ends of the second emitted region β in the X direction, and as an example, the fourth end β2 refers to another outermost end of the second emitted region β in the X direction.

[0145] As in Figure 10 As an example, the third fixed target light source 120 is arranged such that, when the orientation of the mirror 68A of the H-galvanometer reflector 68 is the third orientation, the third fixed target light is emitted onto the central portion of the first emitted region α in a state facing the fundus. The third fixed target light source 120 is illuminated only when the orientation of the mirror 68A is the third orientation. Therefore, the third fixed target light source 120 is illuminated when the orientation of the mirror 68A is the third orientation, and is not illuminated when the mirror 68A is in any other orientation. Note that here, as an example, the third orientation refers to the orientation of the mirror 68A when the emitted light is emitted onto the third end β1, as in... Figure 10 As shown in the example, the third fixed target light source 120 can more generally be illuminated only when the mirror 68A is oriented in a predetermined orientation, which is adjustable to change the position on the fundus where the fixed target light is emitted.

[0146] When the orientation of mirror 68A is the third orientation, the third fixed target light is emitted to the central portion of the first emitted region α in a state facing the fundus via mirrors 68A and 70A. That is, when the orientation of mirror 68A is the third orientation, the third fixed target light is reflected by mirror 68A, the reflected third fixed target light is further reflected by mirror 70A, and the third fixed target light reflected by mirror 70A reaches the central portion of the first emitted region α in a state facing the fundus.

[0147] As in Figure 11 As an example, the fourth fixed target light source 122 is arranged such that, when the orientation of mirror 68A is the fourth orientation, the fourth fixed target light is emitted onto the central portion of the first emitted region α in a state facing the fundus. The fourth fixed target light source 122 is illuminated only when the orientation of mirror 68A is the fourth orientation. Therefore, the fourth fixed target light source 122 is illuminated when the orientation of mirror 68A is the fourth orientation, and is not illuminated when mirror 68A is in any other orientation. Note that here, the fourth orientation refers to the orientation of mirror 68A when the emitted light is emitted onto the fourth end β2, as in... Figure 11As shown in the example, the fourth fixed target light source 122 can more generally be illuminated only when the mirror 68A is oriented in a predetermined orientation, which is adjustable to change the position on the fundus where the fixed target light is emitted.

[0148] When the orientation of mirror 68A is the fourth orientation, the fourth fixed target light is emitted to the central portion of the first emitted region α in a state facing the fundus via mirrors 68A and 70A. That is, when the orientation of mirror 68A is the fourth orientation, the fourth fixed target light is reflected by mirror 68A, the reflected fourth fixed target light is further reflected by mirror 70A, and the fourth fixed target light reflected by mirror 70A reaches the central portion of the first emitted region α in a state facing the fundus.

[0149] Note that when the orientation of mirror 68A is neither the third nor the fourth orientation, that is, when the emitted light is not emitted to the third end β1 or the fourth end β2, the third fixed target light source 120 and the fourth fixed target light source 122 are extinguished.

[0150] Note that in this second exemplary embodiment, as described above, because the H-galvanometer reflector 68 operates rotating at 25 Hz, the afterimage effect allows the subject to perceive the illumination of the third fixed target light source 120 and the fourth fixed target light source 122 as continuous illumination through the subject's eye 38. Although this second exemplary embodiment provides an example of the H-galvanometer reflector 68 operating rotating at 25 Hz in OCT mode, the technology disclosed herein is not limited thereto. For example, it is sufficient that the speed at which the orientation change of the H-galvanometer reflector 68 changes is such that the subject perceives the illumination of the third fixed target light source 120 and the fourth fixed target light source 122 as continuous illumination through the subject's eye 38 due to the afterimage effect. However, regardless of the speed of the orientation change of the H-galvanometer reflector 68, the third fixed target light source 120 and the fourth fixed target light source 122 are controlled by the CPU 74 to illuminate only at the third and fourth orientations of the H-galvanometer reflector 68, respectively, and to emit the corresponding third and fourth fixed target light onto the subject's retina, so that the subject perceives the fixed target as fixed in one position.

[0151] Next, refer to Figure 12 The following is an explanation of the fixed target light control processing (operation as part of the fundus examination device 10B according to the technology disclosed herein) performed by the CPU 74 after procedure 80B in the case of fundus imaging in OCT mode.

[0152] exist Figure 12In the fixed target light control process shown, in step 150, the CPU 74 determines whether the position of the signal light emitted on the fundus is the first end α1. If, in step 150, the position of the signal light emitted on the fundus is the first end α1, a positive determination is made, and the process transitions to step 152. If, in step 150, the position of the signal light emitted on the fundus is not the first end α1, a negative determination is made, and the process transitions to step 156.

[0153] In step 152, the CPU 74 illuminates the first fixed target light source 82 for a given amount of time (e.g., the same amount of illumination time as the first fixed target light source 82 explained in the first exemplary embodiment above), and then the process transitions to step 154.

[0154] In step 156, the CPU 74 determines whether the position on the fundus where the signal light is emitted is the second end α2. If, in step 156, the position on the fundus where the signal light is emitted is the second end α2, a positive determination is made, and the process transitions to step 158. If, in step 156, the position on the fundus where the signal light is emitted is not the second end α2, a negative determination is made, and the process transitions to step 160.

[0155] In step 158, the CPU 74 illuminates the second fixed target light source 84 for a given amount of time (e.g., the same amount of illumination time as the first fixed target light source 82), and then the process transitions to step 154.

[0156] In step 160, the CPU 74 determines whether the location on the fundus where the signal light is emitted is the third end β1. If, in step 160, the location on the fundus where the signal light is emitted is the third end β1, a positive determination is made, and the process transitions to step 162. If, in step 160, the location on the fundus where the signal light is emitted is not the third end β1, a negative determination is made, and the process transitions to step 164.

[0157] In step 162, the CPU 74 illuminates the third fixed target light source 120 for a given amount of time (e.g., the same amount of illumination time as the first fixed target light source 82), and then the process transitions to step 154.

[0158] In step 164, CPU 74 determines whether the location on the fundus where the signal light is emitted is the fourth end β2. If, in step 164, the location on the fundus where the signal light is emitted is the fourth end β2, an affirmative determination is made, and the process transitions to step 166. If, in step 164, the location on the fundus where the signal light is emitted is not the fourth end β2, a negative determination is made, and the process transitions to step 150.

[0159] In step 166, the CPU 74 illuminates the fourth fixed target light source 122 for a given amount of time (e.g., the same amount of illumination time as the first fixed target light source 82), and then the process transitions to step 154.

[0160] In step 154, CPU 74 determines whether the termination condition is met. If the termination condition is not met in step 154, a negative determination is made, and the process transitions to step 150. If the termination condition is met in step 154, a positive determination is made, and the current fixed target light control process ends.

[0161] As explained above, the fundus examination device 10B includes a third fixed target light source 120 that illuminates when the orientation of the mirror 68A is a third orientation, and a fourth fixed target light source 122 that illuminates when the orientation of the mirror 68A is a fourth orientation. Therefore, according to the fundus examination device 10B, the presentation of a fixed target corresponding to the second emitted region β can be achieved.

[0162] Furthermore, in the fundus examination device 10B, the rate of change of orientation of the mirror 68A is due to the afterimage effect, causing the subject to perceive the illumination of the third fixed target light source 120 and the fourth fixed target light source 122 as a continuous illumination rate through the subject's eye 38. Therefore, according to the fundus examination device 10B, when emitted light (signal light, as an example here) is emitted onto the second emitted region β to capture an image, the fixed target can be seen by the subject without interruption.

[0163] Third Exemplary Example

[0164] In the second exemplary embodiment described above, when the imaging area extends from the first emitted light source to region α to the second emitted light source to region β, four light sources are used to present a fixed target to the subject. However, in order to maintain gaze fixation when imaging the peripheral region of the retina, adding additional fixed target light sources may be impractical in some cases due to space limitations within the fundus examination device. A third exemplary embodiment using three light sources to display a fixed target to the subject will now be described, which is useful in this case.

[0165] Note that in this third exemplary embodiment, the same reference numerals are assigned to the same configuration elements as those explained in the first and second exemplary embodiments described above, and their explanations are omitted. The explanations focus primarily on the parts that differ from the exemplary embodiments described above.

[0166] According to this third exemplary embodiment (see...), Figure 1 The fundus examination device 10C differs from the fundus examination device 10B explained in the second exemplary embodiment above in that the fundus examination device 10C does not include the fourth fixed target light source 122 or the frames 124, 126, as in Figure 13 The example shown is in the middle.

[0167] Furthermore, the fundus examination device 10C differs from the fundus examination device 10B in that the fundus examination device 10C includes a plane mirror 182, and that the fundus examination device 10C includes a third fixed target light source 180 instead of a third fixed target light source 120, as in... Figure 13 The example shown is in the middle.

[0168] Furthermore, the difference between the fundus examination device 10C and the fundus examination device 10B in this embodiment may be that the fundus examination device 10C may include a linkage mechanism 181 and a drive source 186, as in Figures 14 to 16 The example shown is in the middle.

[0169] The difference between fundus examination device 10C and fundus examination device 10B also lies in that, for example, in Figure 3 As an example, the second storage segment 78 stores program 80C instead of program 80B.

[0170] The third fixed target light source 180 is an example of a "light source" according to the technology disclosed herein. The third fixed target light source 180 is an LED that emits fixed target light having the same optical characteristics (such as the amount of light, wavelength, and beam diameter) as the first fixed target light source 82 and the second fixed target light source 84. The third fixed target light source 180 is selectively turned on and off under the control of the controller 13.

[0171] In this third exemplary embodiment, the fixed target light is broadly divided into a third fixed target light emitted from the third fixed target light source 180, a first fixed target light, and a second fixed target light. Note that, for ease of explanation in this third exemplary embodiment, the first to third fixed target lights are simply referred to as "fixed target light" unless the distinction between them is not made. Furthermore, in Figures 13 to 16 In the diagram, the light path indicated by a single-dotted line is the light path of the emitted light, while the light path of the fixed target light is indicated by a double-dotted line.

[0172] As in Figure 13 As an example, the third fixed target light source 180 is arranged on the mirror surface 70A of the ellipsoidal mirror 70 at a position separate from the light path of the emitted (scanning) light, and is fixed to the mirror surface 70A. Specifically, the light path of the third fixed target light from the third fixed target light source 180 is not transmitted to the fundus of the subject's eye 38 via the mirror surface 68A.

[0173] As in Figures 14 to 16 As shown as an example, the fundus examination device 10C may include a linkage mechanism 181 as in this embodiment, which is an example of a "moving mechanism" according to the technology disclosed herein. Furthermore, the fundus examination device 10C may include a drive source 186 that generates and outputs driving force under the control of the controller 13. Note that in this third exemplary embodiment, a solenoid is used as an example of drive source 186; however, the technology disclosed herein is not limited to this, and this drive source may be replaced by another drive source (such as a stepper motor).

[0174] Linkage mechanism 181 includes a drive transmission arm 184 and a rotating component 183. (As in...) Figure 15 and Figure 16 As an example, the base end of the rotating member 183 is axially supported on the front end of the drive transmission arm 184 via the rotating shaft P, and the plane mirror 182 is fixed to the front end of the rotating member 183.

[0175] The base of the drive arm 184 is connected to the drive source 186, and the drive arm 184 moves the mirror surface 182A of the plane mirror 182 between a first position and a second position by transmitting the driving force generated by the drive source 186 to the rotating member 183. Note that the mirror surface 182A is an example of a "second reflecting surface" according to the technology disclosed herein. Here, a plane mirror 182 including a mirror surface 182A formed in a planar shape is given as an example; however, the invention is not limited thereto. For example, a reflector including a mirror surface formed in a convex shape, a concave shape, etc., can be used instead of the plane mirror 182 to achieve the emission of fixed target light in a state facing the central portion of the fundus.

[0176] Note that in this third exemplary embodiment, when the orientation of mirror 68A is the third or fourth orientation explained in the second exemplary embodiment described above, the first position refers to the position where mirror 182A reflects the third fixed target light and the reflected third fixed target light is emitted via mirror 70A in a state facing the fundus. The second position refers to the position where the emitted light is separated from the optical path of the emitted light when the emitted light is emitted onto the first emitted region α.

[0177] Since the solenoid is used as the drive source 186 in this third exemplary embodiment, the mirror 182A moves between the first position and the second position by converting the linear forward force of the solenoid core into rotational force through the linkage mechanism 181.

[0178] As in Figure 14 As shown in the example, the third fixed target light source 180 is arranged such that when the orientation of the mirror 68A is the third orientation, the third fixed target light is emitted onto the central portion of the first emitted region α in the state facing the fundus.

[0179] When the orientation of mirror 68A is the third orientation, the third fixed target light is emitted via mirrors 68A and 70A to the central portion of the first emitted region α in the retinal-facing state. That is, when the orientation of mirror 68A is the third orientation, the third fixed target light is reflected by mirror 182A, the reflected third fixed target light is further reflected by mirror 70A, and the third fixed target light reflected by mirror 70A reaches the central portion of the first emitted region α in the retinal-facing state. Therefore, the third fixed target light is not reflected by mirror 68A.

[0180] As in Figure 15 As shown as an example, the third fixed target light source 180 is arranged such that when the orientation of the mirror 68A is the fourth orientation explained in the second exemplary embodiment described above, the fourth fixed target light is emitted onto the central portion of the first emitted region α in a state facing the fundus.

[0181] When the orientation of mirror 68A is the fourth orientation, the fourth fixed target light is emitted to the central portion of the first emitted region α in the state facing the fundus via mirrors 182A and 70A. That is, when the orientation of mirror 68A is the fourth orientation, the fourth fixed target light is reflected by mirror 182A, the reflected fourth fixed target light is further reflected by mirror 70A, and the fourth fixed target light reflected by mirror 70A reaches the central portion of the first emitted region α in the state facing the fundus. Therefore, the fourth fixed target light is not reflected by mirror 68A.

[0182] The third fixed target light source 180 is illuminated only when the orientation of mirror 68A is either the third or fourth orientation.

[0183] As in Figure 16 As an example, when the orientation of mirror 68A is neither the third orientation nor the fourth orientation, that is, when, for example, the emitted light is not emitted to the third end β1 or the fourth end β2, mirror 182A adopts a state of being withdrawn from the second position, and the third fixed target light source 180 is extinguished.

[0184] Next, refer to Figure 17 The following is an explanation of the fixed target light control processing performed by the CPU 74 after procedure 80C in the case of fundus imaging in OCT mode (operation as part of the fundus examination device 10C according to the technology disclosed herein).

[0185] exist Figure 17 In the fixed target light control process shown, firstly in step 200, the CPU 74 determines whether the position of the H-galvanometer reflector 68 corresponds to the position of the second emission range. Here, the position corresponding to the second emission range refers to the position of the H-galvanometer reflector 68 when the signal light is emitted onto the second emission region β.

[0186] In step 200, if the position of the H-galvanometer reflector 68 corresponds to the position of the second emission range, a positive determination is made, and the process transitions to step 202. In step 200, if the position of the H-galvanometer reflector 68 does not correspond to the position of the second emission range, a negative determination is made, and the process transitions to step 214.

[0187] In step 202, CPU 74 determines whether the position of mirror surface 182A of plane mirror 182 is the second position. If, in step 202, the position of mirror surface 182A of plane mirror 182 is the second position, an affirmative determination is made, and the process transitions to step 204. If, in step 202, the position of mirror surface 182A of plane mirror 182 is not the second position, a negative determination is made, and the process transitions to step 208.

[0188] In step 204, CPU 74 moves the mirror surface 182A of the plane mirror 182 to a first position by controlling the drive source 186, and then the process transitions to step 206.

[0189] In step 206, the CPU 74 causes the third fixed target light source 180 to illuminate for a given amount of time (e.g., the same amount of illumination time as the first fixed target light source 82 explained in the first exemplary embodiment above), and then the process transitions to step 208.

[0190] In step 208, the CPU 74 determines whether the signal light has been emitted into the first emitted region α within a given amount of time. Note that the “given amount of time” in the current step 208 refers to a predetermined amount of time from the results of tests using real equipment or computer simulations, etc., as the amount of time required until the mirror surface 182A of the plane mirror 182 is withdrawn from the first position to the second position.

[0191] In step 208, if the signal light is emitted into the first emitted region α within a given time period, a positive determination is made, and the process transitions to step 210. In step 208, if the signal light is not emitted into the first emitted region α within a given time period, a negative determination is made, and the process transitions to step 212.

[0192] In step 210, CPU 74 controls drive source 186 to retract mirror 182A of plane mirror 182 to the second position, and then the process transitions to step 212.

[0193] In step 214, the CPU 74 determines whether the position on the fundus where the signal light is emitted is the first end α1. If, in step 214, the position on the fundus where the signal light is emitted is the first end α1, a positive determination is made, and the process transitions to step 216. If, in step 214, the position on the fundus where the signal light is emitted is not the first end α1, a negative determination is made, and the process transitions to step 218.

[0194] In step 216, the CPU 74 causes the first fixed target light source 82 to illuminate for a given amount of time (e.g., the same amount of illumination time as the third fixed target light source 180), and then the process transitions to step 212.

[0195] In step 218, the CPU 74 determines whether the position on the fundus where the signal light is emitted is the second end α2. If, in step 218, the position on the fundus where the signal light is emitted is the second end α2, a positive determination is made, and the process transitions to step 220. If, in step 218, the position on the fundus where the signal light is emitted is not the second end α2, a negative determination is made, and the process transitions to step 212.

[0196] In step 220, the CPU 74 illuminates the second fixed target light source 84 for a given amount of time (e.g., the same amount of illumination time as the third fixed target light source 180), and then the process transitions to step 212.

[0197] In step 212, CPU 74 determines whether the termination condition is met. If the termination condition is not met in step 212, a negative determination is made, and the process transitions to step 200. If the termination condition is met in step 212, a positive determination is made, and the current fixed target light control process ends.

[0198] As explained above, in the fundus examination device 10C, when the orientation of the mirror 68A is a third or fourth orientation, the mirror 182A is positioned at a first position, and the third fixed target light is reflected by the mirror 182A and emitted onto the central portion of the fundus. Furthermore, when the orientation of the mirror 68A is not a third or fourth orientation, the fundus examination device 10C retracts the mirror 182A to a second position. Therefore, according to the fundus examination device 10C, the presentation of the fixed target corresponding to the second emitted light region β can be achieved.

[0199] The controller 13 can be arranged to select the light source among the light sources 82, 84, and 180 based on which part of the fundus is being imaged by the fundus examination device 10C, so as to provide (preferably central) gaze fixation for all scanning fields of view. More specifically, the controller 13 can initially operate in a static fixation module manner to control the patient alignment module (PAM) (e.g., to fix the gaze of the subject's eye 38 before the fundus is imaged by the fundus examination device 10C). The controller 13 can then switch to dynamic fixation mode operation when the fundus is imaged by the fundus examination device 10C, and perform the following processes based on information indicating at least one of the following to provide (central) gaze fixation during imaging in the central or peripheral region of the fundus, control the emission of fixation target light by the selected light source (multiple light sources), and control the positioning of the mirror 182A by the moving mechanism: (i) the orientation of the mirror 68A; (ii) the range of orientation change of the mirror 68A during scanning; and (iii) the rate of orientation change of the mirror 68A such that the fixation target light emitted by the selected light source proceeds along a predetermined optical path for fixing the gaze of the subject's eye 38.

[0200] The controller 13 can use a "fixed constraint map" as described herein to select a fixed target light source and set the position of the mirror 182A. The fixed constraint map defines a first variable the area in two-dimensional space traversed by the orientation of the H-galvanometer mirror (also referred to herein as "scan offset") and a second variable the orientation range of the H-galvanometer mirror 68 obtained during scanning (also referred to herein as "scan width"), each area being associated with one or more fixed target light sources suitable for use within the range of scan offset and scan width spanning that area. For example, in an embodiment combining the four fixed target light sources 82, 84, 120, and 122 of the second embodiment with the fixed target light source 180 of this embodiment, the controller 13 can use a fixed constraint map as described herein to select a fixed target light source and set the position of the mirror 182A. Figure 18The stored fixation constraint map shown is used to select a fixed target light source for gaze fixation. A fixation constraint map can be obtained that determines the corresponding orientation of the H-galvanometer mirror 68, which allows fixed light from the fixed target light source to travel along a corresponding predetermined optical path for gaze fixation of the subject's eye. This information is used to determine which (which) fixed target light sources can be used for each considered combination of H-galvanometer mirror orientation (scan offset) and orientation range (scan width) of the H-galvanometer mirror 68 obtained during scanning. Figure 18 The exemplary fixed constraint diagram shown has: a usable area that can be fixed at the center of one or more fixed target light sources 82, 84, 120 and 122 (which is in Figure 18 (with shadows added), and in the case where the plane mirror 182 is in the first position, the area that can be used is fixed around the target light source 180 (in). Figure 18 (Without shadows added) and the area where two or more of the fixed target light sources 82, 84, 120 and 122 can be used in combination when the fixed target light source 180 and the plane mirror 182 are in the first position (shown in) Figure 18 (Between the unshaded area and the dashed line). When it is possible to use more than one fixed target light source for eye fixation according to the fixed constraint diagram, one or more of these fixed target light sources can be selected according to a predetermined level (in other words, the assigned priority). The on-time of each fixed target light source 82, 84, 120, 122, and 180 can also be determined, wherein the minimum "on" time is determined by the brightness of the target, and the maximum "on" time is determined by the blurring effect caused by the movement of the H-galvanometer reflector 68.

[0201] The controller 13 can use the stored fixation constraint map to determine whether the scanning parameters (scan offset and scan width) meet the conditions for center fixation and / or peripheral fixation. If the conditions for peripheral fixation are met, the controller 13 can control the moving mechanism to set the mirror 182A in the first position and activate the third fixation target light source 180. On the other hand, if center fixation is selected using one of the fixation target light sources 82, 84, 120, and 122 using the fixation constraint map and a predetermined level, the selected fixation target light source is controlled by the controller 13 to activate at the appropriate H-galvanometer reflector orientation, as described above. The fixation target light source used for eye fixation can be dynamically changed when the scanning position changes during imaging of the subject's eye 38.

[0202] Note that in the third exemplary embodiment described above, the driving force generated by the drive source 186 is transmitted to the linkage mechanism 181 to move the mirror 182A between the first and second positions; however, the technology disclosed herein is not limited thereto. For example, as Figure 21 As shown, a manual operating lever 270 can be used instead of the drive source 186.

[0203] In this configuration, one end of the manual operating lever 270 is fixed to the base end of the drive transmission arm 184 of the linkage mechanism 181, and moving the operating lever 270 in the direction of the dashed arrow causes the rotating member 183 to rotate, moving the mirror 182A between the first and second positions. Then, with the mirror 182A positioned in the first position, the third fixed target light source 180 is illuminated. Note that with the mirror 182A already moved to the first position, the plane mirror 182 can be detected by a sensor (not shown in the figure), and with the plane mirror 182 already detected by the sensor, the third fixed target light source 180 can be illuminated under the control of the controller 13. Furthermore, the third fixed target light source 180 can be illuminated according to a specific instruction received by the receiving device 22. Figure 21 The configuration shown as an example, when using SLO mode for fundus imaging, allows the subject to see the third fixed target light before imaging, thus fixing the subject's gaze.

[0204] Fourth exemplary embodiment

[0205] The explanation regarding the fixed position of the third fixed target light source 180 has already been given in the third exemplary embodiment above; however, in this fourth exemplary embodiment, the following section concerns the movable third fixed target light source 232 (see...). Figure 19 Explanation of the circumstances under which it is used.

[0206] Note that in this fourth exemplary embodiment, the same configuration elements as those explained in the first to third exemplary embodiments described above are assigned the same reference numerals, and their explanations are omitted. The explanations focus primarily on the parts that differ from the exemplary embodiments described above.

[0207] According to the present fourth exemplary embodiment, the fundus examination device 10D (see Figure 1 The difference between the fundus examination device 10C and the fundus examination device 10D according to the third exemplary embodiment described above is that the fundus examination device 10D includes a platform 230 instead of a plane mirror 182, as in Figure 19 The example shown is in the middle.

[0208] The difference between fundus examination device 10D and fundus examination device 10C is that fundus examination device 10D includes a third fixed target light source 232 instead of a third fixed target light source 180.

[0209] The difference between the fundus examination device 10D and the fundus examination device 10C also lies in, for example, in Figure 3 As an example, auxiliary storage segment 78 stores program 80D instead of program 80C.

[0210] As in Figure 19 As shown as an example, the fundus examination device 10D may be provided with a platform 230 fixed to the front end of the rotating member 183, as in this embodiment, and the third fixed target light source 232 may be fixed to the center portion of the platform 230.

[0211] The characteristics of the fixed target light of the third fixed target light source 232 are the same as those of the fixed target light of the third fixed target light source 180 explained in the third exemplary embodiment described above, and the third fixed target light source 232 is selectively lit and turned off under the control of the controller 13.

[0212] In this fourth exemplary embodiment, the fixed target light is broadly divided into a third fixed target light emitted from the third fixed target light source 232, a first fixed target light, and a second fixed target light. Note that, for ease of explanation in this fourth exemplary embodiment, the first to third fixed target lights are simply referred to as "fixed target light" unless the distinction between the first and third fixed target lights is not made. Furthermore, in... Figure 19 In the diagram, the light path indicated by a single-dotted line is the light path of the emitted light, while the light path of the fixed target light is indicated by a double-dotted line.

[0213] Drive arm 184 can be in a first position (e.g., by transmitting the driving force generated by drive source 186 to rotating member 183) by transmitting the driving force generated by drive source 186 to rotating member 183. Figure 19 The third fixed target light source 232 is moved between the position shown and the second position. Here, the first position refers to the position where, in the case that the orientation of the mirror 68A is the third or fourth orientation explained in the second exemplary embodiment described above, the third fixed target light emitted from the third fixed target light source 232 is reflected by the mirror 70A and the reflected third fixed target light is emitted in a state facing the fundus. The second position refers to the position where the emitted light is separated from the optical path of the emitted light in the case that the emitted light is emitted onto the first emitted region α.

[0214] When the orientation of mirror 68A is the third orientation, the third fixed target light source 232 is arranged at the first position, the third fixed target light from the third fixed target light source 232 is reflected by mirror 70A, and the third fixed target light reflected by mirror 70A reaches the center part of the first emitted region α in the state facing the fundus.

[0215] When the orientation of mirror 68A is the fourth orientation, the third fixed target light source 232 is arranged at the first position, the third fixed target light from the third fixed target light source 232 is reflected by mirror 70A, and the third fixed target light reflected by mirror 70A reaches the center part of the first emitted region α in the state facing the fundus.

[0216] The third fixed target light source 232 is illuminated only when the orientation of mirror 68A is either the third or fourth orientation.

[0217] Note that when the orientation of mirror 68A is the third or fourth orientation, that is, when, for example, the emitted light is not emitted to the third end β1 or the fourth end β2, the third fixed target light source 232 adopts a state of being withdrawn from the second position, and the third fixed target light source 232 is extinguished.

[0218] Next, refer to Figure 20 This is followed by an explanation of the fixed-target light control processing performed by the CPU 74 after procedure 80D in the case of fundus imaging in OCT mode (operation as part of the fundus examination device 10D according to the technology disclosed herein). Note that, with Figure 17 The same steps in the flowchart shown are assigned the same reference numerals, and their explanations are omitted.

[0219] Figure 20 The fixed target light control processing shown is Figure 17 The difference in the fixed target light control process shown is that it includes steps 250 to 254 instead of steps 202 to 206, and that it includes step 256 instead of step 210.

[0220] In step 250, the CPU 74 determines whether the position of the third fixed target light source 232 is the second position. If the position of the third fixed target light source 232 is the second position in step 250, an affirmative determination is made, and the process transitions to step 252. If the position of the third fixed target light source 232 is not the second position in step 250, a negative determination is made, and the process transitions to step 208.

[0221] In step 252, the CPU 74 moves the third fixed target light source 232 to the first position by controlling the drive source 186, and then the process transitions to step 254.

[0222] In step 254, the CPU 74 illuminates the third fixed target light source 232 for a given amount of time (e.g., the same amount of illumination time as the first fixed target light source 82 explained in the first exemplary embodiment above), and then the process transitions to step 208.

[0223] In step 256, the CPU 74 controls the drive source 186 to retract the third fixed target light source 232 back to the second position, and then the process transitions to step 212.

[0224] As explained above, in the fundus examination device 10D, when the orientation of the mirror 68A is a third or fourth orientation, the third fixed target light source 232 is positioned at a first position, and the third fixed target light is reflected by the mirror 70A and emitted onto the central portion of the fundus. Furthermore, when the orientation of the mirror 68A is not a third or fourth orientation, the fundus examination device 10D retracts the third fixed target light source 232 to a second position. Therefore, according to the fundus examination device 10D, the presentation of a second fixed target corresponding to the peripheral portion of the fundus and emitted into region β can be achieved.

[0225] Similar to the third embodiment described above, the controller 13 can be arranged to use Figure 18 The type of fixed constraint diagram shown is used to select light sources in light sources 82, 84 and 232 based on information indicating at least one of the following, control the emission of fixed target light by the selected light source, and control the positioning of the moving mechanism on the third fixed target light source 232: (i) the orientation of mirror 68A; (ii) the orientation range of mirror 68A; and (iii) the speed of the orientation change of mirror 68A, such that the fixed target light emitted by the selected light source travels along a predetermined optical path for fixing the gaze of the subject's eye 38.

[0226] Note that in the fourth exemplary embodiment described above, the driving force generated by the driving source 186 is transmitted to the linkage mechanism 181 to move the third fixed target light source 232 between the first and second positions; however, the technology disclosed herein is not limited thereto. For example, as Figure 22 As shown, a manual operating lever 270 can be used instead of the drive source 186.

[0227] In this configuration, one end of the manual operating lever 270 is fixed to the base end of the drive transmission arm 184 of the linkage mechanism 181, and moving the operating lever 270 in the direction of the dashed arrow causes the rotating member 183 to rotate, moving the third fixed target light source 232 between the first and second positions. Then, with the third fixed target light source 232 positioned in the first position, it is illuminated. Note that when the third fixed target light source 232 has moved to the first position, either the third fixed target light source 232 or the platform 230 can be detected by a sensor (not shown in the figure), and when either the third fixed target light source 232 or the platform 230 has been detected by the sensor, the third fixed target light source 232 can be illuminated under the control of the controller 13. Furthermore, the third fixed target light source 232 can be illuminated according to a specific instruction received by the receiving device 22. According to... Figure 22 The example shown in the image illustrates a configuration in which, when the fundus is imaged using SLO mode, a third fixed target light is seen by the subject before imaging, allowing the subject's gaze to be fixed.

[0228] Although examples of a pair of concave mirrors configured with slit mirror 66 and ellipsoidal mirror 70 have been given in each of the exemplary embodiments above, the invention is not limited thereto. For example, spherical mirrors at angles, aspherical mirrors, a pair of parabolic mirrors, a pair of parabolic cylindrical mirrors, lens systems, or optical systems employing suitable combinations of these may be used instead of slit mirror 66.

[0229] Although examples have been given of programs 80A, 80B, 80C, 80D (hereinafter simply referred to as "program 80A, etc.") being read from auxiliary storage segment 78 in each of the exemplary embodiments described above, programs 80A, etc., do not necessarily need to be stored in auxiliary storage segment 78 from the outset. For example, as Figure 23 As shown, the program 80A, etc., can first be stored on a freely selectable portable storage medium 300, such as a solid-state drive (SSD), a universal serial bus (USB) memory, or an optical disc read-only memory (CD-ROM). In this case, the program 80A, etc., stored on the storage medium 300 is installed into the fundus examination device 10A (10B, 10C, 10D) (hereinafter referred to as "fundus examination device 10A, etc."), and the installed program is executed by the CPU 74.

[0230] The program 80A, etc., can be stored in the storage segment of another computer, server device, etc., connected to the fundus examination device 10A, etc., via a communication network (not shown in the figure), and the program 80A, etc., can be downloaded upon request from the fundus examination device 10A, etc. In this case, the downloaded program 80A, etc., is executed by the CPU 74.

[0231] Furthermore, the fixed target light control processing explained in each of the exemplary embodiments described above is merely an example. Therefore, it is self-evident that unnecessary steps may be omitted, new steps may be added, and the processing sequence may be rearranged without departing from the spirit of this disclosure. Moreover, each processing item included in the fixed target light control processing may be implemented individually by a hardware configuration (such as an FPGA, ASIC, etc.), or may be implemented by a combination of a computer employing both software and hardware configurations.

[0232] Furthermore, although explanations have been given in each of the exemplary embodiments above regarding examples of the polygon mirror 44 scanning in the Y direction and the V-galvanometer mirror 60 scanning in the Y direction being arranged on the light-incident side of the dichroic mirror 64, the dichroic mirror 64 can be arranged at a position separate from the focal point of the slit mirror in the optical axis direction, and the polygon mirror 44 or the V-galvanometer mirror 60 scanning in the Y direction can be arranged at the focal point of the slit mirror. In this case, the polygon mirror 44 or the V-galvanometer mirror 60 functions as a shared scanning optical system used during SLO image acquisition and OCT image acquisition.

[0233] Furthermore, although an explanation has been given regarding the shared optical axis through which the light generated by the dichroic mirror 64 for SLO and for OCT passes, a beam splitter (such as a polarizing beam splitter) or an optical component (such as a semi-reflective mirror) can be used instead of the dichroic mirror 64.

[0234] In each of the above exemplary embodiments, information regarding such... Figure 1 Explanation of the example shown: polygon mirror 44 and V-galvanometer mirror 60 are arranged on the light incident side of dichroic mirror 64, and H-galvanometer mirror 68, shared by SLO and OCT for X-direction scanning, is arranged on the light emitting side of dichroic mirror 64. Figure 24 Showing the corresponding Figure 1 The configuration of the SLO unit 32, OCT unit 34, and shared optical system 36 is shown. (As in...) Figure 24 As shown in the example, the main body of the device includes a dichroic mirror 1064, an SLO engine 1032A, and an OCT engine 1034A. A scanning system 1044 is arranged between the dichroic mirror 1064 and the SLO engine 1032A. Furthermore, a scanning system 1060 is arranged between the dichroic mirror 1064 and the OCT engine 1034A. A scanning system 1068 is arranged between the dichroic mirror 1064 and the subject's eye 1038.

[0235] Note that the scanning system 1044 corresponds to the polygon mirror 44, and the SLO engine 1032A is transmitted from... Figure 1The portion obtained by removing the polygon mirror 44 from the SLO unit 32. The scanning system 1060 corresponds to the V-galvanometer reflector 60, and the OCT engine 1034A is obtained by removing the polygon mirror 44 from the SLO unit 32. Figure 1 The portion obtained by removing the V-galvanometer reflector 60 from the OCT unit 34. The scanning system 1068 corresponds to the H-galvanometer reflector 68.

[0236] The following modifications can be made to the scanning optical system.

[0237] Figure 25 This illustrates a first modified example of a scanning optical system. (As shown in...) Figure 25 As an example, the two-dimensional scanning optical system 1104 for SLO is arranged on one light incident side (SLO engine 1032A side) of the dichroic mirror 1064, and the two-dimensional scanning optical system 1102 for OCT is arranged on the other light incident side (OCT engine 1034A side) of the dichroic mirror 1064.

[0238] Figure 26 A second modified example of a scanning optical system is shown. (As in...) Figure 26 As an example, the shared two-dimensional scanning optical system 1200 used by SLO and OCT is arranged on the light-emitting side of the dichroic mirror 64.

[0239] Furthermore, it goes without saying that in all the scanning optical systems explained above, a similar scan can be performed by swapping the X and Y directions.

[0240] Although an explanation has been given regarding the use of an ellipsoidal mirror as an optical component in split-pass scanning, another concave mirror (such as a parabolic mirror) or an optical component (such as a lens) can be used instead. Optical components comprising multiple focal points can be used as optical components in split-pass scanning. In this case, the positional relationship between the optical component, the scanning optics system, and the subject's eye can be as follows.

[0241] In the first aspect, the subject's eyes are positioned at a focal position f1, and the shared two-dimensional scanning optical system used by SLO and OCT is positioned at another focal position f2.

[0242] In the second aspect, the subject's eyes are positioned at a focal point f1, the two-dimensional scanning optical system used by SLO is positioned at another focal point f2, and the two-dimensional scanning optical system used by OCT is positioned at yet another focal point f3.

[0243] In the third aspect, the subject's eye is positioned at a focal position f1, a shared one-dimensional scanning optical system used by SLO and OCT and scanning light in the first direction is positioned at another focal position f2, a one-dimensional scanning optical system used by SLO and scanning light in the second direction intersecting the first direction (e.g., orthogonal direction) is positioned at yet another focal position f3, and a one-dimensional scanning optical system used in OCT and scanning light in the second direction is positioned at a position optically equivalent to the other focal position f3.

[0244] Note that in each of the above aspects, the subject's eyes and the scanning optical system may be positioned at a location optically equivalent to the focal point rather than at the focal point.

[0245] The second exemplary embodiment described above provides an example of the selective use of the first fixed target light source 82, the second fixed target light source 84, the third fixed target light source 120, and the fourth fixed target light source 122; however, the technology disclosed herein is not limited thereto. For example, such as Figure 27 As shown, the first fixed target light source 82 and the second fixed target light source 84 can be omitted, and a third fixed target light source 120 and a fourth fixed target light source 122 are provided. Note that in this case, the region defined by the first emitted region α and the second emitted region β (i.e., the region spanning from the third end β1 to the fourth end β2) corresponds to the "central region" according to the technology disclosed herein, the third fixed target light source 120 operates as the "first light source" according to the technology disclosed herein, and the fourth fixed target light source 122 operates as the "second light source" according to the technology disclosed herein.

[0246] Furthermore, the linkage mechanism 181 has been given as an example in the third exemplary embodiment described above; however, the technology disclosed herein is not limited thereto, and for example, a moving mechanism capable of moving the mirror 182A between a first position and a second position can be used instead of the linkage mechanism 181, the first position enabling the emission of third and fourth fixed target lights in a state facing the fundus, and the second position separating the light path from the emitted light. Examples of the moving mechanism include a mechanism having linear motion performed by receiving the driving force of a solenoid or stepper motor. The moving mechanism can move the mirror 182A in the Z direction, the X direction, or the Y direction.

[0247] Similarly, the fourth exemplary embodiment may employ a moving mechanism capable of moving the third fixed target light source 232 between a first position and a second position, the first position enabling the emission of third and fourth fixed target light in a state facing the fundus, and the second position separating the light path from the emitted light.

[0248] In the first embodiment described above, the first orientation of the mirror 68A (as an example of a reflecting surface) of the H-galvanometer reflector 68 causes light to be emitted onto a first end α1, which is an end in a specific direction in the central region of the fundus. However, the first light source 82 does not need to be configured to emit a first fixed target light when the mirror 68A is oriented in this specific manner, and can optionally be configured to be illuminated when the reflecting surface is oriented in a predetermined orientation that can be adjusted to change the position on the fundus where the fixed target light is emitted. Therefore, the gaze direction of the subject's eye 38 can be changed to and maintained in multiple different directions, such that different regions of the fundus of the subject's eye associated with different gaze directions can be imaged.

[0249] All publications, patent applications and technical standards mentioned in this specification are incorporated herein by reference to the same extent that each individual publication, patent application or technical standard is specifically and individually indicated to be incorporated by reference.

[0250] Explanation of reference numerals in the attached figures

[0251] 10A, 10B, 10C, 10D Fundus Examination Equipment

[0252] 32 SLO units

[0253] 34 OCT units

[0254] 68A, 70A, 182A mirror finish

[0255] 74 CPU

[0256] 82 First Fixed Target Light Source

[0257] 84 Second Fixed Target Light Source

[0258] 120, 180, 232 Third fixed target light source

[0259] 122 Fourth Fixed Target Light Source

[0260] 184 linkage mechanism

[0261] 186 driver source

[0262] α was first launched into the region

[0263] α1 First end

[0264] α2 Second end

[0265] β was second and was launched into the region.

[0266] β1 Third end

[0267] β2 Fourth end

Claims

1. An ophthalmic device, comprising: Light source (82; 84； 120; 122), which is configured to emit fixed target light; A reflective surface (68A) is configured to reflect the fixed target light and further configured to reflect the scanning light emitted by the emitting segment, and to scan the scanning light in a specific direction by changing its orientation, wherein the emitting segment is a source different from the light source (82; 84; 120; 122) and is the source of the scanning light, and the fixed target light and the scanning light are incident on the reflective surface (68A) through different optical paths; A concave mirror (70A) is arranged such that when the subject's eye (38) is positioned at the focal point of the concave mirror (70) during use of the ophthalmic device, the scanning light reflected by the reflecting surface (68A) is incident on the fundus of the subject's eye (38). The ophthalmic device is configured such that when the subject's eye (38) is positioned at the focal point of the concave mirror (70) during use of the ophthalmic device, and when the light source (82; 84) emits the fixed target light, the fixed target light and the scanning light are simultaneously incident on the fundus via different optical paths, both of which propagate through the reflecting surface (68A), the concave mirror (70A), and the focal point, and the fixed target light travels along a predetermined optical path for fixing the gaze of the subject's eye (38); A controller (13; 74) configured to control the emission of the fixed target light by the light source (82; 84; 120; 122) to the fixed target light when the reflective surface (68A) scans the scanning light, by controlling the light source (82; 84; 120; 122) to emit the fixed target light only when the reflective surface (68A) is oriented in a predetermined orientation, such that the fixed target light travels along the predetermined optical path used to fix the gaze of the subject's eye (38); and At least one additional light source is arranged such that when the subject's eye (38) is positioned at the focal point of the concave mirror (70) during use of the ophthalmic device, and when each of the at least one additional light source emits the fixed target light, the corresponding fixed target light and the scanning light simultaneously incident on the fundus via different optical paths. In this case, the different optical paths all travel through the concave mirror (70A) and the focal point, while the optical path of the fixed target light does not pass through the reflecting surface (68A), or the different optical paths all travel through the reflecting surface (68A), the concave mirror (70A) and the focal point; The controller (13; 74) is further configured to select a light source from the light source and control the emission of the fixed target light by the selected light source based on information indicating at least one of the orientation of the reflective surface (68A), the orientation range of the reflective surface (68A), and the speed at which the orientation of the reflective surface (68A) changes, such that the fixed target light emitted by the selected light source travels along a predetermined optical path for fixing the gaze of the subject's eye (38).

2. The ophthalmic device according to claim 1, configured such that when the subject's eye (38) is positioned at the focal point of the concave mirror (70) during use of the ophthalmic device, and when the light source (82; 84; 120; 122) emits a fixed target light, the corresponding fixed target light and the scanning light are simultaneously incident on different locations of the fundus via different optical paths, the different optical paths both traveling through the concave mirror (70A) and the focal point.

3. The ophthalmic device according to claim 1, wherein, The fixed target light and the scanning light are incident on the reflecting surface (68A) at different incident angles, and the concave mirror (70) is an ellipsoidal mirror.

4. The ophthalmic device according to any one of claims 1-3, wherein the predetermined orientation is adjustable to change the position on the fundus where the fixed target light is emitted.

5. The ophthalmic device according to any one of claims 1-3, further comprising a second reflective surface (182A) arranged at a first position separate from the optical path of the scanning light when the scanning light is emitted onto the peripheral region of the fundus, and configured to reflect a fixed target light onto the fundus via the concave mirror surface (70A) along the predetermined optical path when the subject's eye (38) is at the focal point of the concave mirror (70) during use of the ophthalmic device.

6. The ophthalmic device according to claim 4, further comprising a second reflective surface (182A) arranged at a first position separate from the optical path of the scanning light when the scanning light is emitted onto the peripheral region of the fundus, and configured to reflect a fixed target light onto the fundus via the concave mirror (70A) along the predetermined optical path when the subject's eye (38) is at the focal point of the concave mirror (70) during use of the ophthalmic device.

7. The ophthalmic device of claim 5, wherein the second reflective surface (182A) is movable between the first position and the second position, the second position being separated from the optical path of the scanning light when the scanning light is emitted onto the central region of the fundus, the ophthalmic device further comprising: A moving mechanism (181) is configured to move the second reflective surface (182A) between the first position and the second position. as well as A controller (74) is configured to control the moving mechanism (181) and the light source (180; 232), the light source being configured to emit the fixed target light reflected from the second reflective surface (182A), such that the second reflective surface (182A) is arranged at the first position and the light source (180; 232) is illuminated when the orientation of the reflective surface (68A) is such that the scanning light is emitted onto the peripheral area, and the second reflective surface (182A) is arranged at the second position when the orientation of the reflective surface (68A) is such that the scanning light is emitted onto the central area.

8. The ophthalmic device of claim 6, wherein the second reflective surface (182A) is movable between the first position and the second position, the second position being separated from the optical path of the scanning light when the scanning light is emitted onto the central region of the fundus, the ophthalmic device further comprising: A moving mechanism (181) is configured to move the second reflective surface (182A) between the first position and the second position. as well as A controller (74) is configured to control the moving mechanism (181) and the light source (180; 232), the light source being configured to emit the fixed target light reflected from the second reflective surface (182A), such that the second reflective surface (182A) is arranged at the first position and the light source (180; 232) is illuminated when the orientation of the reflective surface (68A) is such that the scanning light is emitted onto the peripheral area, and the second reflective surface (182A) is arranged at the second position when the orientation of the reflective surface (68A) is such that the scanning light is emitted onto the central area.

9. The ophthalmic device according to claim 7 or 8, wherein the controller (74) is configured to select a light source from the light sources (82; 84; 120; 122) based on information indicating at least one of the orientation, the orientation range of the reflective surface (68A), and the speed at which the orientation of the reflective surface (68A) changes, control the emission of the fixed target light by the selected light source (82; 84; 120; 122), and control the positioning of the second reflective surface (182A) by the moving mechanism (181) such that the fixed target light emitted by the selected light source travels along a predetermined optical path for fixing the gaze of the subject's eye (38).

10. The ophthalmic device according to any one of claims 1-3, further comprising a second light source (232) arranged at a first position separate from the optical path of the scanning light when the scanning light is emitted onto the peripheral region of the fundus, and configured to emit fixed target light onto the fundus along a predetermined optical path via the concave mirror (70A) when the subject's eye (38) is at the focal point of the concave mirror (70) during use of the ophthalmic device.

11. The ophthalmic device according to claim 4, further comprising a second light source (232) arranged at a first position separate from the optical path of the scanning light when the scanning light is emitted onto the peripheral region of the fundus, and configured to emit fixed target light onto the fundus along a predetermined optical path via the concave mirror (70A) when the subject's eye (38) is at the focal point of the concave mirror (70) during use of the ophthalmic device.

12. The ophthalmic device of claim 10, wherein the second light source (232) is movable between the first position and the second position, the second position being separated from the optical path of the scanning light when the scanning light is emitted onto the central region of the fundus, and the ophthalmic device further comprises: A moving mechanism (184) is configured to move the second light source (232) between the first position and the second position. as well as A controller (74) is configured to control the moving mechanism (184) and the emission of fixed target light by the second light source (232), such that the second light source (232) is arranged at the first position and illuminated with the orientation of the reflective surface (68A) such that the scanning light is emitted onto the peripheral area, and that the second light source (232) is arranged at the second position with the orientation of the reflective surface (68A) such that the scanning light is emitted onto the central area.

13. The ophthalmic device of claim 11, wherein the second light source (232) is movable between the first position and the second position, the second position being separated from the optical path of the scanning light when the scanning light is emitted onto the central region of the fundus, and the ophthalmic device further comprises: A moving mechanism (184) is configured to move the second light source (232) between the first position and the second position. as well as A controller (74) is configured to control the moving mechanism (184) and the emission of fixed target light by the second light source (232), such that the second light source (232) is arranged at the first position and illuminated with the orientation of the reflective surface (68A) such that the scanning light is emitted onto the peripheral area, and that the second light source (232) is arranged at the second position with the orientation of the reflective surface (68A) such that the scanning light is emitted onto the central area.

14. The ophthalmic device according to claim 12 or 13, wherein the controller (74) is configured to select a light source from the light sources (82; 84; 120; 122) based on information indicating at least one of the orientation, the orientation range of the reflective surface (68A) and the speed at which the orientation of the reflective surface (68A) changes, control the emission of the selected light source to the fixed target light, and control the positioning of the moving mechanism (184) to the second light source (232) such that the fixed target light emitted by the selected light source travels along a predetermined optical path for fixing the gaze of the subject's eye (38).

15. The ophthalmic device according to any one of claims 1 to 3, 6 to 8, and 11 to 13, wherein the light source is configured such that when the subject's eye (38) is placed at the focal point of the concave mirror (70) during use of the ophthalmic device, the light source is configured to emit the fixed target light such that the fixed target light incident on the fundus is perceived by the subject as continuously lit.

16. The ophthalmic device according to claim 4, configured such that when the subject's eye (38) is at the focal point of the concave mirror (70) during use of the ophthalmic device, the light source is configured to emit the fixed target light such that the fixed target light incident on the fundus is perceived by the subject as continuously lit.

17. The ophthalmic device of claim 5, configured such that when the subject's eye (38) is at the focal point of the concave mirror (70) during use of the ophthalmic device, the light source is configured to emit the fixed target light such that the fixed target light incident on the fundus is perceived by the subject as continuously lit.

18. The ophthalmic device of claim 9, configured such that when the subject's eye (38) is at the focal point of the concave mirror (70) during use of the ophthalmic device, the light source is configured to emit the fixed target light such that the fixed target light incident on the fundus is perceived by the subject as continuously lit.

19. The ophthalmic device of claim 10, configured such that when the subject's eye (38) is placed at the focal point of the concave mirror (70) during use of the ophthalmic device, the light source is configured to emit the fixed target light such that the fixed target light incident on the fundus is perceived by the subject as continuously lit.

20. The ophthalmic device of claim 14, configured such that when the subject's eye (38) is placed at the focal point of the concave mirror (70) during use of the ophthalmic device, the light source is configured to emit the fixed target light such that the fixed target light incident on the fundus is perceived by the subject as continuously lit.

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