JP7801869B2 - Ophthalmic apparatus, method for controlling ophthalmic apparatus, and program - Google Patents

Description

This invention relates to an ophthalmic device, a control method for an ophthalmic device, and a program.

Ophthalmic devices used for screening and treating eye diseases are required to be able to easily observe and photograph the fundus of the examinee's eye over a wide field of view. Known examples of such devices include optical coherence tomography and scanning laser ophthalmoscopes (SLOs). SLOs are devices that scan the fundus with light and form images of the fundus by detecting the returning light with a light-receiving device.

Various ophthalmic devices have been proposed for observing the fundus with such a wide field of view.

For example, Patent Document 1 discloses a fundus camera in an ophthalmic device in which a fixation target is provided around an objective lens, and a fixation target moving mechanism is provided on the outer surface of the objective lens to move the fixation target so as to change the distance from the objective lens.

Japanese Patent Application Laid-Open No. 2003-079579

In recent years, the area of interest on the fundus has expanded beyond the central area of the fundus, including the optic disc and macula, to include the peripheral area. Therefore, there is a demand for a method for more easily photographing or measuring the peripheral area of the fundus.

There is a need for a method to more easily photograph or measure the subject's eye at a wide angle, not only for the fundus but also for the anterior segment.

The present invention was made in consideration of these circumstances, and one of its purposes is to provide a new technology for more easily photographing or measuring the subject's eye at a wide angle.

A first aspect of the embodiment is an optical system including an objective lens, an imaging optical system that receives light from the subject's eye via the objective lens, and an OCT optical system that is coupled to the optical path of the imaging optical system and projects measurement light that has passed through the optical path onto the subject's eye via the objective lens, and detects interference light between return light of the measurement light and reference light; an angle changing mechanism that changes the direction of the optical axis of the optical system by tilting the optical system; a fixation system that projects a fixation light beam toward the subject's eye from an emission position of the fixation light beam that can be changed in its relative position with respect to the optical axis; The ophthalmologic device includes a control unit that changes the angle between the visual axis of the test eye and the optical axis based on an OCT measurement position in an eye examination image, projects the fixation light beam from the emission position corresponding to the OCT measurement position, and controls the OCT optical system while the fixation light beam is being projected to perform OCT measurement of the test eye; an image forming unit that forms an OCT image of the test eye based on the detection results of the interference light; and an analysis unit that identifies the position of the OCT image in the image of the test eye based on the emission position.

In a second aspect of the embodiment, in the first aspect, the control unit causes the fixation system to project the fixation light beam for each of two or more OCT measurement positions, and the analysis unit identifies the position of the OCT image in the image of the test eye for each of the two or more OCT measurement positions based on the emission position in the fixation system.

In a third aspect of the embodiment, in the first or second aspect, the fixation system includes an external fixation system that projects the fixation light beam from outside the objective lens toward the subject's eye from the emission position that has a known positional relationship with the optical axis.

In a fourth aspect of the embodiment, in the first aspect, the fixation system includes an internal fixation system that includes an internal fixation light source whose position relative to the optical axis can be changed and projects the fixation light beam onto the subject's eye via the objective lens, and an external fixation system that includes an external fixation light source whose position relative to the optical axis can be changed and projects the fixation light beam from outside the objective lens toward the subject's eye from a position of the external fixation light source that has a known positional relationship with the optical axis.

In a fifth aspect of the embodiment, in the fourth aspect, when the OCT measurement position is within a predetermined range including a position corresponding to the optical axis in the image of the subject's eye, the control unit causes the internal fixation system to project the fixation light beam onto the subject's eye, and the analysis unit identifies the position of the OCT image in the image of the subject's eye based on the fixation position where the fixation light beam is projected; and when the OCT measurement position is outside the predetermined range including a position corresponding to the optical axis in the image of the subject's eye, the control unit causes the external fixation system to project the fixation light beam onto the subject's eye, and the analysis unit identifies the position of the OCT image in the image of the subject's eye based on the fixation position where the fixation light beam is projected.

In a sixth aspect of the embodiment, in the fourth or fifth aspect, the control unit projects the fixation light beam using the internal fixation system or the external fixation system for each of two or more OCT measurement positions, and the analysis unit identifies the position of the OCT image in the image of the test eye for each of the two or more OCT measurement positions based on the fixation position at which the fixation light beam is projected.

In a seventh aspect of the embodiment, in any one of the third to sixth aspects, the external fixation system is fixed relative to the optical system.

In an eighth aspect of the embodiment, in any of the first to seventh aspects, the angle change mechanism includes a first angle change mechanism that changes the angle that the optical axis makes with respect to the horizontal direction in the up-down direction, and a second angle change mechanism that changes the angle that the optical axis makes with respect to the vertical direction in the left-right direction.

A ninth aspect of the embodiment is any one of the first to eighth aspects, further comprising an operation unit, and the OCT measurement position is set based on the operation performed on the image of the subject's eye using the operation unit.

A tenth aspect of the present embodiment is a control method for an ophthalmic device including an optical system including an objective lens, an imaging optical system that receives light from the test eye via the objective lens, and an OCT optical system that is coupled to the optical path of the imaging optical system and projects measurement light that has passed through the optical path onto the test eye via the objective lens to detect interference light between return light of the measurement light and reference light; an angle changing mechanism that changes the direction of the optical axis of the optical system by tilting the optical system; and a fixation system that projects a fixation light beam toward the test eye from an emission position of the fixation light beam whose relative position with respect to the optical axis is changeable, wherein the method includes: This is an ophthalmic device control method including a control step of changing the angle between the visual axis of the test eye and the optical axis based on the OCT measurement position in the image of the test eye, projecting the fixation light beam from the emission position corresponding to the OCT measurement position, and controlling the OCT optical system while the fixation light beam is being projected to perform OCT measurement on the test eye; an image formation step of forming an OCT image of the test eye based on the detection results of the interference light; and an analysis step of identifying the position of the OCT image in the image of the test eye based on the emission position.

In an eleventh aspect of the embodiment, in the tenth aspect, the control step causes the fixation light beam to be projected by the fixation system for each of two or more OCT measurement positions, and the analysis step identifies the position of the OCT image in the image of the test eye based on the emission position in the fixation system for each of the two or more OCT measurement positions.

In a twelfth aspect of the embodiment, in the tenth or eleventh aspect, the fixation system includes an external fixation system that projects the fixation light beam from an emission position that has a known positional relationship with the optical axis from outside the objective lens toward the subject's eye.

In a thirteenth aspect of the embodiment, in the tenth aspect, the fixation system includes an internal fixation system that includes an internal fixation light source whose position relative to the optical axis is changeable and projects the fixation light beam onto the subject's eye via the objective lens, and an external fixation system that includes an external fixation light source whose position relative to the optical axis is changeable and projects the fixation light beam from outside the objective lens toward the subject's eye from a position of the external fixation light source that has a known positional relationship with the optical axis.

In a fourteenth aspect of the embodiment, in the thirteenth aspect, when the OCT measurement position is within a predetermined range including a position corresponding to the optical axis in the image of the subject's eye, the control step causes the internal fixation system to project the fixation light beam onto the subject's eye, and the analysis step identifies the position of the OCT image in the image of the subject's eye based on the fixation position where the fixation light beam is projected, and when the OCT measurement position is outside the predetermined range including a position corresponding to the optical axis in the image of the subject's eye, the control step causes the external fixation system to project the fixation light beam onto the subject's eye, and the analysis step identifies the position of the OCT image in the image of the subject's eye based on the fixation position where the fixation light beam is projected.

In a fifteenth aspect of the embodiment, in the thirteenth or fourteenth aspect, the control step projects the fixation light beam by the internal fixation system or the external fixation system for each of two or more OCT measurement positions, and the analysis step identifies the position of the OCT image in the image of the test eye for each of the two or more OCT measurement positions based on the fixation position at which the fixation light beam is projected.

In a sixteenth aspect of the present embodiment, in any one of the twelfth to fifteenth aspects, the external fixation system is fixed relative to the optical system.

In a seventeenth aspect of the embodiment, in any of the tenth to sixteenth aspects, the angle change mechanism includes a first angle change mechanism that changes the angle that the optical axis makes with respect to the horizontal direction in the up-down direction, and a second angle change mechanism that changes the angle that the optical axis makes with respect to the vertical direction in the left-right direction.

In an 18th aspect of the embodiment, in any of the 10th to 17th aspects, the OCT measurement position is set based on the operation performed on the image of the subject's eye using the operation unit.

A 19th aspect of the present embodiment is a program that causes a computer to execute each step of the method for controlling an ophthalmic apparatus according to any one of the 10th to 18th aspects.

It is possible to combine any of the configurations related to the above-mentioned aspects.

The present invention provides a new technology for more easily photographing or measuring the subject's eye at a wide angle.

1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmologic apparatus according to an embodiment. FIG. 2 is a schematic diagram showing an example of the configuration of an external fixation unit according to the embodiment. FIG. 2 is a schematic diagram for explaining a fixation light beam according to the embodiment. FIG. 2 is a schematic diagram for explaining a fixation light beam according to the embodiment. 1 is a schematic diagram illustrating an example of the configuration of an optical system of an ophthalmologic apparatus according to an embodiment. FIG. 2 is a schematic diagram illustrating an example of the configuration of a control system of an ophthalmologic apparatus according to an embodiment. 3A and 3B are schematic diagrams for explaining swing and tilt operations of the ophthalmologic apparatus according to the embodiment. FIG. 2 is a schematic diagram for explaining fixation control according to the embodiment. FIG. 2 is a schematic diagram for explaining control of the ophthalmologic apparatus according to the embodiment. FIG. 2 is a schematic diagram for explaining control of the ophthalmologic apparatus according to the embodiment. 3A and 3B are schematic diagrams for explaining the operation of the ophthalmologic apparatus according to the embodiment. FIG. 2 is a schematic diagram illustrating an example of the configuration of a data processing unit of the ophthalmologic apparatus according to the embodiment. FIG. 2 is a schematic diagram illustrating an example of the configuration of a data processing unit of the ophthalmologic apparatus according to the embodiment. 10 is a flowchart illustrating an example of an operation of the ophthalmologic apparatus according to the embodiment. 10 is a flowchart illustrating an example of an operation of the ophthalmologic apparatus according to the embodiment. 10 is a flowchart illustrating an example of an operation of the ophthalmologic apparatus according to the embodiment. 10 is a flowchart illustrating an example of an operation of the ophthalmologic apparatus according to the embodiment.

An example of an embodiment of an ophthalmic device, an ophthalmic device control method, and a program according to the present invention will be described in detail with reference to the drawings. Note that in the embodiment, it is possible to arbitrarily incorporate the techniques described in the documents cited in this specification.

The ophthalmic device according to the embodiment includes an optical system capable of photographing and OCT measurement of the subject's eye, an angle change mechanism that changes the orientation of the optical axis of the optical system by tilting the optical system, and a fixation system that projects a fixation light beam toward the subject's eye from an emission position (projection position, position of the fixation light source) of the fixation light beam, the relative position of which with respect to the optical axis of the optical system can be changed.

In some embodiments, the angle change mechanism includes at least one of a swing mechanism and a tilt mechanism. The swing mechanism is, for example, a movement mechanism that rotates the optical system in an arc in the left-right direction around the pupil of the subject's eye. This makes it possible to change the angle that the optical axis of the optical system makes with respect to the vertical direction (vertical plane) in the left-right direction. The tilt mechanism is, for example, a movement mechanism that rotates the optical system in an arc in the up-down direction around the pupil of the subject's eye. This makes it possible to change the angle that the optical axis of the optical system makes with respect to the horizontal direction (horizontal plane) in the up-down direction.

In some embodiments, the optical system includes a fixation system. The fixation system includes at least one of an internal fixation system and an external fixation system. The internal fixation system projects a fixation light beam onto the subject's eye via an objective lens to present a fixation target. The external fixation system projects a fixation light beam onto the subject's eye without via an objective lens to present a fixation target.

The ophthalmic device controls at least one of the angle change mechanism and the fixation system based on the OCT measurement position set in the captured image (or observed image) of the subject's eye, projects a fixation light beam from the fixation light beam emission position corresponding to the OCT measurement position, and performs OCT measurement on the subject's eye while the fixation light beam is being projected. The ophthalmic device identifies the position of the OCT image in the captured image based on the fixation light beam emission position. In some embodiments, the ophthalmic device performs registration processing between the captured image and the OCT image, and displays the captured image and OCT image after registration processing on the display means.

This makes it possible to easily acquire wide-angle OCT images of the subject's eye. In particular, since the search range for registration processing is determined from the emission position of the fixation beam, the processing load can be significantly reduced.

In some embodiments, the ophthalmic device projects a fixation beam using a fixation system at each of two or more OCT measurement positions, and identifies the position of the OCT image in the captured image based on the emission position of the fixation beam.

In some embodiments, the ophthalmic device determines two or more OCT measurement positions based on a montage imaging range set in a captured image (or observed image) of the subject's eye, sequentially projects a fixation beam using a fixation system at each of the two or more determined OCT measurement positions, and sequentially identifies the position of the OCT image in the captured image based on the emission position of the fixation beam. In some embodiments, the ophthalmic device performs an overlap determination process between the OCT image whose position has been determined and an adjacent OCT image, and acquires the next OCT image based on the determination result, thereby acquiring an OCT montage image. In some embodiments, the ophthalmic device performs a registration process between the captured image and the OCT montage image, and displays the captured image and OCT montage image after the registration process on a display means.

The control method for an ophthalmic device according to the embodiment includes one or more steps for controlling the above-described ophthalmic device. The program according to the embodiment causes a computer (processor) to execute each step of the control method for an ophthalmic device according to the embodiment. The recording medium according to the embodiment is a non-transitory recording medium (storage medium) on which the program according to the embodiment is recorded.

In this specification, a processor includes circuits such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), and a programmable logic device (e.g., an SPLD (Simple Programmable Logic Device), a CPLD (Complex Programmable Logic Device), or an FPGA (Field Programmable Gate Array)). The processor realizes the functions of the embodiment by, for example, reading and executing a program stored in a memory circuit or a storage device. The memory circuit or storage device may be included in the processor. Additionally, the memory circuit or storage device may be located outside the processor.

The following describes an ophthalmic device according to an embodiment that has a swing mechanism and a tilt mechanism, but the configuration according to the embodiment is not limited to this. For example, the ophthalmic device may have only one of the swing mechanism and the tilt mechanism.

In the following embodiment, the ophthalmic device includes an optical coherence tomography device and a fundus camera. While swept-source OCT is used for this optical coherence tomography device, the type of OCT is not limited to this, and other types of OCT (spectral domain OCT, time domain OCT, Unfas OCT, etc.) may also be used.

The ophthalmic device according to the embodiment may also include any one of a scanning laser ophthalmoscope, a slit lamp ophthalmoscope, a surgical microscope, etc. The ophthalmic device according to the embodiment may also include any one or more of an eye refraction examination device, a tonometer, a specular microscope, a wavefront analyzer, a perimeter, a microperimeter, etc.

Hereinafter, the x direction is the direction perpendicular to the optical axis direction of the objective lens (left-right direction, horizontal direction), the y direction is the direction perpendicular to the optical axis direction of the objective lens (up-down direction, vertical direction), and the z direction is the direction of the optical axis of the objective lens.

<Configuration>
[Optical system]
As shown in FIG. 1 , the ophthalmic apparatus 1 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic and control unit (not shown). The fundus camera unit 2 is provided with an optical system and mechanisms for acquiring a front image of the subject's eye E. The OCT unit 100 is provided with a portion of the optical system and mechanisms for performing OCT. Other portions of the optical system and mechanisms for performing OCT are provided in the fundus camera unit 2. The arithmetic and control unit includes one or more processors that perform various calculations and controls. In addition to these, the ophthalmic apparatus 1 may be provided with optional elements or units such as a member for supporting the subject's face (such as a chin rest or forehead rest) and a lens unit for switching the target area for OCT (e.g., an attachment for anterior segment OCT). Furthermore, the ophthalmic apparatus 1 includes a pair of anterior segment cameras 5A and 5B.

[Fundus camera unit 2]
The fundus camera unit 2 is provided with an optical system for photographing the fundus Ef of the subject's eye E. The acquired image of the fundus Ef (called a fundus image, fundus photograph, etc.) is a front image such as an observed image or a photographed image. The observed image is obtained by video capture using near-infrared light. The photographed image is a still image using flash light. Furthermore, the fundus camera unit 2 can photograph the anterior segment Ea of the subject's eye E to acquire a front image (anterior segment image).

The fundus camera unit 2 includes an illumination optical system 10 and an imaging optical system 30. The illumination optical system 10 irradiates the subject's eye E with illumination light. The imaging optical system 30 detects return light of the illumination light from the subject's eye E. The measurement light from the OCT unit 100 is guided to the subject's eye E via an optical path within the fundus camera unit 2, and the return light is guided to the OCT unit 100 via the same optical path.

Light (observation illumination light) output from the observation light source 11 of the illumination optical system 10 is reflected by a reflecting mirror 12 with a curved reflective surface, passes through a condenser lens 13, and passes through a visible light cut filter 14 to become near-infrared light. The observation illumination light is then focused near the imaging light source 15, reflected by a mirror 16, and passes through relay lenses 17 and 18, an aperture 19, and a relay lens 20. The observation illumination light is then reflected from the peripheral portion of the aperture mirror 21 (the area surrounding the aperture), passes through a dichroic mirror 46, and is refracted by an objective lens 22 to illuminate the subject's eye E (fundus Ef or anterior segment Ea). Return light of the observation illumination light from the subject's eye E is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through a aperture formed in the central region of the aperture mirror 21, passes through an imaging focusing lens 31, and is reflected by a mirror 32. Furthermore, this returning light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged on the light-receiving surface of the image sensor 35 by the condenser lens 34. The image sensor 35 detects the returning light at a predetermined frame rate. The focus of the photographing optical system 30 is adjusted to match the fundus Ef or the anterior segment Ea.

Light output from the imaging light source 15 (imaging illumination light) travels the same path as the observation illumination light and is irradiated onto the fundus Ef. Return light of the imaging illumination light from the subject's eye E travels the same path as the return light of the observation illumination light and is guided to the dichroic mirror 33, passes through the dichroic mirror 33, is reflected by the mirror 36, and is focused by the condenser lens 37 onto the light-receiving surface of the image sensor 38.

For example, the display unit provided in the ophthalmologic apparatus 1 displays an image (observation image) based on fundus reflected light detected by the image sensor 35. When the focus of the imaging optical system 30 is adjusted to the anterior segment, an observation image of the anterior segment of the subject's eye E is displayed. The display unit also displays an image (captured image) based on fundus reflected light detected by the image sensor 38. The display unit that displays the observation image and the display unit that displays the captured image may be the same or different. When a similar image is taken by illuminating the subject's eye E with infrared light, an infrared captured image is displayed.

The ophthalmologic device 1 includes a fixation system. The fixation system includes an internal fixation system and an external fixation system. The function of the internal fixation system is realized by an LCD (Liquid Crystal Display) 39. The function of the external fixation system is realized by an external fixation unit 23.

The LCD (Liquid Crystal Display) 39 displays a fixation target and a visual target for visual acuity testing. A portion of the light beam output from the LCD 39 is reflected by the half mirror 33A, reflected by the mirror 32, passes through the photographic focusing lens 31, and passes through the hole in the aperture mirror 21. The light beam that passes through the hole in the aperture mirror 21 passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus Ef.

The display pixels on the screen of LCD 39 function as an internal fixation light source. The fixation position of the subject's eye E can be changed by changing the display position of the fixation target on the screen of LCD 39. Examples of fixation positions include a fixation position for acquiring an image centered on the macula, a fixation position for acquiring an image centered on the optic disc, a fixation position for acquiring an image centered on the center of the fundus between the macula and the optic disc, and a fixation position for acquiring an image of a region far removed from the macula (periphery of the fundus). The ophthalmic device 1 according to some embodiments includes a GUI (Graphical User Interface) or the like for specifying at least one of these fixation positions. The ophthalmic device 1 according to some embodiments includes a GUI or the like for manually moving the fixation position (display position of the fixation target).

The configuration for presenting a movable fixation target to the subject's eye E is not limited to a display device such as an LCD. For example, a movable fixation target can be generated by selectively illuminating multiple light sources in a light source array (such as a light-emitting diode (LED) array). Furthermore, a movable fixation target can be generated using one or more movable light sources.

The external fixation unit 23 projects a fixation light beam onto the subject's eye E from an emission position whose relative position with respect to the optical axis (objective optical axis) of the objective lens 22 can be changed, without passing through the objective lens 22. The external fixation unit 23, whose emission position of the fixation light beam can be changed with respect to the optical axis of the objective lens 22, is configured to be movable integrally with the fundus camera unit 2 (optical system including the LCD 39). For example, the external fixation unit 23 is fixed to a housing that houses the optical system that constitutes the fundus camera unit 2.

Figure 2 shows a schematic example of the configuration of the external fixation unit 23. In Figure 2, parts that are the same as those in Figure 1 are given the same reference numerals, and descriptions will be omitted where appropriate.

The external fixation unit 23 includes an annular member 23A that can be installed on or near the outer periphery of the objective lens 22, and a fixation light source holding member 23B, one end of which is connected to the outer periphery of the annular member 23A and the other end of which extends approximately in the radial direction from the optical axis O (the optical axis of the objective lens 22, the objective optical axis). The fixation light source holding member 23B includes multiple fixation light sources (external fixation light sources) arranged in the radial direction. The multiple fixation light sources are controlled by a control unit, described below, so that one of them is turned on or all of them are turned off. In this embodiment, the multiple fixation light sources are fixation light sources 23-1 to 23-4.

The fixation light source holding member 23B is configured to be rotatable around the optical axis O. In some embodiments, the fixation light source holding member 23B is configured to rotate relative to the annular member 23A. In some embodiments, the annular member 23A and the fixation light source holding member 23B are configured to rotate integrally.

In some embodiments, the fixation light source holding member 23B automatically rotates around the optical axis O under control of the control unit described below. For example, the control unit can drive a rotation mechanism included in the external fixation unit 23 by controlling the fixation light source holding member 23B.

In some embodiments, the fixation light source holding member 23B is configured to be manually rotated around the optical axis O. For example, the external fixation unit 23 includes a sensor and is configured to be able to detect the radial angle of the manually rotated fixation light source holding member 23B. As with the case of automatically rotating the fixation light source holding member 23B, the external fixation unit 23 can be configured to project the fixation light beam onto the subject's eye E from the desired emission position while referring to the detection results obtained by the sensor.

By rotating the fixation light source holding member 23B around the optical axis O and turning on one of the fixation light sources 23-1 to 23-4, it becomes possible to project a fixation light beam onto the subject's eye E from various directions over a wider range than the internal fixation LCD 39.

In some embodiments, the fixation light source holding member 23B includes two or more arm members connected to each other. Each of the fixation light sources 23-1 to 23-4 is provided on one of the two or more arm members. The arm members are rotatable at their connection points. This folding mechanism allows the fixation light source holding member 23B to be stored.

In some embodiments, the fixation light source holding member 23B includes two or more arm members that can slide relative to each other in the radial direction. Each of the fixation light sources 23-1 to 23-4 is provided on one of the two or more arm members. This sliding mechanism allows the fixation light source holding member 23B to be stored.

In some embodiments, the external fixation unit 23 is configured to be detachable from the fundus camera unit 2.

Figure 3 shows a schematic diagram of an example of the arrangement of fixation light sources 23-1 to 23-4 of the external fixation unit 23. In Figure 3, parts that are the same as those in Figures 1 and 2 are designated by the same reference numerals, and descriptions will be omitted where appropriate.

A fixation light beam from any display pixel of the LCD 39 is projected onto the subject's eye E via the objective lens 22 as a fixation target IFp. In contrast, a fixation light beam from any of the fixation light sources 23-1 to 23-4 is projected onto the subject's eye E without passing through the objective lens 22. At this time, the fixation light sources 23-1 to 23-4 are positioned so that the distance from the subject's eye E (e.g., the pupil) is R0. Of the fixation light sources 23-1 to 23-4, the fixation light source that is closest to the subject's eye E in the z direction (fixation light source 23-4 in Figure 3) is positioned so that its distance from the subject's eye E is greater than Dw. The distance Dw may be the working distance between the subject's eye E and the lens surface of the objective lens 22.

This allows the accommodation state of the subject's eye E to be aligned with respect to each of the fixation light sources 23-1 to 23-4. This reduces the effects of differences in the accommodation state of the subject's eye E depending on the fixation position due to external fixation.

Figure 4 shows a schematic diagram of another example of the arrangement of the fixation light sources 23-1 to 23-4 of the external fixation unit 23. In Figure 4, parts that are the same as those in Figures 1 and 2 are designated by the same reference numerals, and descriptions will be omitted where appropriate.

A fixation light beam from any display pixel on the screen of the LCD 39 is projected onto the subject's eye E via the objective lens 22 as a fixation target IFp, as in FIG. 3. In contrast, a fixation light beam from any of the fixation light sources 23-1 to 23-4 is projected onto the subject's eye E without passing through the objective lens 22. In this case, the fixation light sources 23-1 to 23-4 are arranged in a direction perpendicular to the optical axis of the objective lens 22. The fixation light sources 23-1 to 23-4 are positioned so that their distance from the subject's eye E is greater than Dw. The distance Dw may be the working distance between the subject's eye E and the lens surface of the objective lens 22.

This allows the fixation target to be easily presented to the subject's eye E, even though the distances of the fixation light sources 23-1 to 23-4 relative to the subject's eye E are different.

As described above, each of the fixation light sources 23-1 to 23-4 can project a fixation light beam toward the subject's eye E from an emission position that has a known positional relationship with the optical axis of the objective lens 22, from outside the objective lens 22 (without going through the objective lens 22).

As shown in FIG. 1, the focusing optical system 60 generates a split index used for focus adjustment of the subject's eye E. The focusing optical system 60 moves along the optical path (illumination optical path) of the illumination optical system 10 in conjunction with the movement of the imaging focusing lens 31 along the optical path (imaging optical path) of the imaging optical system 30. The reflecting rod 67 is insertable into and removable from the illumination optical path. When performing focus adjustment, the reflective surface of the reflecting rod 67 is tilted relative to the illumination optical path. The focusing light output from the LED 61 passes through the relay lens 62, is split into two beams by the split index plate 63, passes through the two-hole diaphragm 64, is reflected by the mirror 65, and is first imaged and reflected by the condenser lens 66 on the reflective surface of the reflecting rod 67. The focusing light then passes through the relay lens 20, is reflected by the aperture mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus Ef. The fundus reflection light of the focusing light is guided to the image sensor 35 along the same path as the return light of the observation illumination light. Manual focusing and autofocusing can be performed based on the received light image (split target image).

The dichroic mirror 46 combines the optical path for fundus imaging and the optical path for OCT. The dichroic mirror 46 reflects light in the wavelength band used for OCT and transmits light for fundus imaging. The OCT optical path (optical path for measurement light) is provided with a collimator lens unit 40, an optical path length changer 41, an optical scanner 42, an OCT focusing lens 43, a mirror 44, and a relay lens 45, in this order from the OCT unit 100 side to the dichroic mirror 46 side.

The optical path length change unit 41 is movable in the direction of the arrow shown in Figure 1, changing the length of the OCT optical path. This change in optical path length is used to correct the optical path length according to the axial length of the eye, adjust the interference state, and more. The optical path length change unit 41 includes a corner cube and a mechanism for moving it.

The optical scanner 42 is positioned optically conjugate with the pupil of the subject's eye E. The optical scanner 42 deflects the measurement light LS passing through the OCT optical path. The optical scanner 42 is, for example, a galvanometer scanner capable of two-dimensional scanning.

The OCT focusing lens 43 is moved along the optical path of the measurement light LS to adjust the focus of the OCT optical system. The movement of the imaging focusing lens 31, the movement of the focus optical system 60, and the movement of the OCT focusing lens 43 can be controlled in a coordinated manner.

[Anterior Eye Cameras 5A and 5B]
The anterior eye cameras 5A and 5B are used to determine the relative position between the optical system of the ophthalmic apparatus 1 and the subject's eye E, similar to the invention disclosed in Japanese Patent Application Laid-Open No. 2013-248376. The anterior eye cameras 5A and 5B are provided on the surface of a housing (such as the fundus camera unit 2) that houses the optical system, facing the subject's eye E. The ophthalmic apparatus 1 determines the three-dimensional relative position between the optical system and the subject's eye E by analyzing two anterior eye images acquired substantially simultaneously from different directions by the anterior eye cameras 5A and 5B. The analysis of the two anterior eye images may be similar to the analysis disclosed in Japanese Patent Application Laid-Open No. 2013-248376. The number of anterior eye cameras may be any number equal to or greater than two.

In this example, the position of the subject's eye E (i.e., the relative position between the subject's eye E and the optical system) is determined using two or more anterior segment cameras, but the method for determining the position of the subject's eye E is not limited to this. For example, the position of the subject's eye E can be determined by analyzing a front image of the subject's eye E (e.g., an observation image of the anterior segment Ea). Alternatively, a means for projecting an index onto the cornea of the subject's eye E can be provided, and the position of the subject's eye E can be determined based on the projection position of this index (i.e., the detection state of the corneal reflected light beam of this index).

[OCT unit 100]
As illustrated in Fig. 5, the OCT unit 100 is provided with an optical system for performing swept-source OCT. This optical system includes an interference optical system. This interference optical system has the following functions: splitting light from a wavelength-variable light source (swept-wavelength light source) into measurement light and reference light; generating interference light by superimposing return light of the measurement light from the subject's eye E on the reference light that has passed through the reference light path; and detecting this interference light. The detection result (detection signal) of the interference light obtained by the interference optical system is a signal indicating the spectrum of the interference light, and is sent to the arithmetic and control unit (control unit 210, image forming unit 220, data processing unit 230).

The light source unit 101 includes, for example, a near-infrared wavelength-tunable laser that changes the wavelength of the emitted light at high speed. Light L0 output from the light source unit 101 is guided by optical fiber 102 to polarization controller 103, where its polarization state is adjusted. Light L0 with its polarization state adjusted is guided by optical fiber 104 to fiber coupler 105, where it is split into measurement light LS and reference light LR.

The reference light LR is guided by the optical fiber 110 to the collimator 111, where it is converted into a parallel beam, and then guided to the corner cube 114 via the optical path length correction element 112 and the dispersion compensation element 113. The optical path length correction element 112 acts to match the optical path length of the reference light LR with that of the measurement light LS. The dispersion compensation element 113 acts to match the dispersion characteristics between the reference light LR and the measurement light LS. The corner cube 114 is movable in the direction of incidence of the reference light LR, thereby changing the optical path length of the reference light LR.

The reference light LR that has passed through the corner cube 114 passes through the dispersion compensation member 113 and the optical path length correction member 112, is converted from a parallel beam into a focused beam by the collimator 116, and enters the optical fiber 117. The reference light LR that has entered the optical fiber 117 is guided to the polarization controller 118 where its polarization state is adjusted, is guided by the optical fiber 119 to the attenuator 120 where the light amount is adjusted, and is then guided by the optical fiber 121 to the fiber coupler 122.

Meanwhile, the measurement light LS generated by the fiber coupler 105 is guided through the optical fiber 127 and converted into a parallel beam by the collimator lens unit 40, and passes through the optical path length change unit 41, optical scanner 42, OCT focusing lens 43, mirror 44, and relay lens 45. After passing through the relay lens 45, the measurement light LS is reflected by the dichroic mirror 46, refracted by the objective lens 22, and enters the subject's eye E. The measurement light LS is scattered and reflected at various depth positions in the subject's eye E. The return light of the measurement light LS from the subject's eye E travels the same path in the opposite direction as the outward path, guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128. The incident end of the optical fiber 127 onto which the measurement light LS is incident is positioned approximately conjugate with the fundus Ef of the subject's eye E.

Fiber coupler 122 generates interference light by combining (causing interference between) measurement light LS incident via optical fiber 128 and reference light LR incident via optical fiber 121. Fiber coupler 122 splits the interference light at a predetermined splitting ratio (e.g., 1:1) to generate a pair of interference light LC. The pair of interference light LC is guided to detector 125 via optical fibers 123 and 124, respectively.

The detector 125 is, for example, a balanced photodiode. The balanced photodiode includes a pair of photodetectors that respectively detect a pair of interference light beams LC, and outputs the difference between the pair of detection results obtained by these photodetectors. The detector 125 sends this output (detection signal) to the DAQ (Data Acquisition System) 130.

The DAQ 130 is supplied with a clock KC from the light source unit 101. The clock KC is generated in the light source unit 101 in synchronization with the output timing of each wavelength swept within a predetermined wavelength range by the tunable light source. For example, the light source unit 101 optically delays one of the two branched lights obtained by branching the light L0 of each output wavelength, and then generates the clock KC based on the result of detecting the combined light. The DAQ 130 samples the detection signal input from the detector 125 based on the clock KC. The DAQ 130 sends the sampling result of the detection signal from the detector 125 to an arithmetic and control unit (such as the control unit 210).

In this example, both an optical path length changer 41 for changing the length of the optical path (measurement optical path, measurement arm) of the measurement light LS and a corner cube 114 for changing the length of the optical path (reference optical path, reference arm) of the reference light LR are provided. However, only one of the optical path length changer 41 and the corner cube 114 may be provided. It is also possible to change the difference between the measurement optical path length and the reference optical path length using optical components other than these.

[Control system]
Fig. 6 shows an example of the configuration of a control system of the ophthalmic apparatus 1. Some of the components included in the ophthalmic apparatus 1 are omitted in Fig. 6. In Fig. 6, the same components as those in Figs. 1 to 5 are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate.

The control unit 210, image forming unit 220, and data processing unit 230 are provided, for example, in the aforementioned arithmetic and control unit.

<Control unit 210>
The control unit 210 executes various controls and includes a main control unit 211 and a storage unit 212.

<Main control unit 211>
The main controller 211 includes a processor (e.g., a control processor) and controls each part (including each element shown in FIGS. 1 to 5) of the ophthalmologic apparatus 1. For example, the main controller 211 controls each part of the optical system of the fundus camera unit 2 shown in FIGS. 1 to 5, each part of the optical system of the OCT unit 100, the anterior eye cameras 5A and 5B, the xyz movement mechanism 150, the swing mechanism 151, the tilt mechanism 152, the image forming unit 220, the data processing unit 230, and a user interface (UI) 240.

Control of the fundus camera unit 2 includes control of the focusing drive units 31A and 43A, control of the image sensors 35 and 38, control of the optical path length change unit 41, control of the optical scanner 42, and control of the external fixation unit 23.

Control of the focusing driver 31A includes control to move the imaging focusing lens 31 in the optical axis direction. Control of the focusing driver 43A includes control to move the OCT focusing lens 43 in the optical axis direction.

Control of image sensors 35 and 38 includes control of the light-receiving sensitivity of the image sensor, control of the frame rate (light-receiving timing, exposure time), control of the light-receiving area (position, size, dimensions), and control of the readout of the light-receiving results from the image sensor.

Control of the LCD 39 includes control of the fixation position (emission position of the fixation light beam, projection position of the fixation light beam on the fundus) based on internal fixation. For example, the main control unit 211 displays a fixation target at a position on the screen of the LCD 39 that corresponds to the fixation position set manually or automatically. The main control unit 211 can also change (continuously or stepwise) the display position of the fixation target displayed on the LCD 39. This allows the fixation target to be moved (i.e., the fixation position can be changed). The display position and movement pattern of the fixation target can be set manually or automatically. Manual setting is performed using, for example, a GUI. Automatic setting is performed by, for example, the data processing unit 230.

Control over the optical path length change unit 41 includes control to change the optical path length of the measurement light LS. The main control unit 211 controls a drive unit that drives the corner cube of the optical path length change unit 41 to move the optical path length change unit 41 along the optical path of the measurement light LS and change the optical path length of the measurement light LS.

Control of the optical scanner 42 includes control of the scan mode, scan range (scan start position, scan end position), scan speed, etc. By controlling the optical scanner 42, the main control unit 211 can perform OCT scanning with the measurement light LS on the desired area in the measurement region (image capture region).

Control of the external fixation unit 23 includes control of the fixation position due to external fixation. For example, the main control unit 211 controls the external fixation unit 23 according to the fixation position set manually or automatically, rotates the fixation light source holding member 23B around the optical axis O, and turns on one of the fixation light sources 23-1 to 23-4. This allows the fixation light beam to be projected onto the subject's eye E from an emission position corresponding to the set fixation position without passing through the objective lens 22. The main control unit 211 also controls the external fixation unit 23 to change the emission position of the fixation light beam (continuously or stepwise). This allows the fixation target due to external fixation to be moved (i.e., the fixation position to be changed). The position and movement pattern of the fixation target due to external fixation can be set manually or automatically. Manual setting is performed using, for example, a GUI. Automatic setting is performed by, for example, the main control unit 211 or the data processing unit 230.

The main control unit 211 also controls the observation light source 11, the imaging light source 15, the focus optical system 60, etc.

Control of the OCT unit 100 includes control of the light source unit 101, control of the reference driver 114A, control of the detector 125, and control of the DAQ 130.

Control of the light source unit 101 includes controlling the on/off of the light source, controlling the amount of light emitted from the light source, controlling the wavelength sweep range, the wavelength sweep speed, and controlling the timing of light emission for each wavelength component.

Control over the reference driver 114A includes control to change the optical path length of the reference light LR. The main controller 211 controls the reference driver 114A to move the corner cube 114 along the optical path of the reference light LR, thereby changing the optical path length of the reference light LR.

Control of the detector 125 includes control of the light receiving sensitivity of the detection elements, control of the frame rate (light receiving timing), control of the light receiving area (position, size, dimensions), and control of the readout of the light receiving results for the detection elements.

Control of the DAQ 130 includes control of the capture (capture timing, sampling timing) of the detection results of the interference light obtained by the detector 125, and control of the readout of the interference signal corresponding to the detection results of the captured interference light.

Control of the anterior eye cameras 5A and 5B includes control of the light receiving sensitivity of each camera, control of the frame rate (light receiving timing), and synchronization control of the anterior eye cameras 5A and 5B.

The xyz movement mechanism 150 moves the fundus camera unit 2 (optical system) in the x, y, and z directions. In a typical example, the xyz movement mechanism 150 includes at least a mechanism for moving the fundus camera unit 2 in the x direction (left-right direction), a mechanism for moving it in the y direction (up-down direction), and a mechanism for moving it in the z direction (depth direction, front-back direction). The mechanism for movement in the x direction includes, for example, an x-stage that can move in the x direction and an x-movement mechanism that moves the x-stage. The mechanism for movement in the y direction includes, for example, a y-stage that can move in the y direction and a y-movement mechanism that moves the y-stage. The mechanism for movement in the z direction includes, for example, a z-stage that can move in the z direction and a z-movement mechanism that moves the z-stage. Each movement mechanism includes a pulse motor as an actuator and operates under the control of the main control unit 211.

Control of the xyz movement mechanism 150 is used for alignment and tracking. Tracking involves moving the device optical system in accordance with the eye movement of the subject's eye E. When tracking is performed, alignment and focus adjustment are performed beforehand. Tracking is a function that maintains an optimal positional relationship where alignment and focus are achieved by having the position of the device optical system follow the eye movement. In some embodiments, the xyz movement mechanism 150 is configured to be controlled to change the optical path length of the reference light (and therefore the optical path length difference between the optical path of the measurement light and the optical path of the reference light).

In the case of manual alignment, the user operates the user interface 240 to move the optical system relative to the subject's eye E so that the displacement of the subject's eye E relative to the optical system is canceled. For example, the main control unit 211 controls the xyz movement mechanism 150 by outputting a control signal corresponding to the operation on the user interface 240 to the xyz movement mechanism 150, thereby moving the optical system relative to the subject's eye E.

In the case of auto-alignment, the main controller 211 controls the xyz movement mechanism 150 to move the optical system relative to the subject's eye E so that displacement of the subject's eye E relative to the optical system is canceled. Specifically, as described in JP 2013-248376 A, trigonometry-based calculations are performed based on the positional relationship between the pair of anterior eye cameras 5A and 5B and the subject's eye E, and the main controller 211 controls the xyz movement mechanism 150 so that the subject's eye E is positioned in a predetermined relationship relative to the optical system. In some embodiments, the main controller 211 controls the xyz movement mechanism 150 to move the optical system relative to the subject's eye E by outputting control signals to the xyz movement mechanism 150 so that the optical axis of the optical system approximately coincides with the axis of the subject's eye E and the distance of the optical system from the subject's eye E is a predetermined working distance. Here, the working distance is a predetermined value also known as the working distance of the objective lens 22, and corresponds to the distance between the subject's eye E and the optical system during measurement (photography) using the optical system.

The swing mechanism 151 rotates the fundus camera unit 2 left and right around the pupil of the subject's eye E. This makes it possible to change the horizontal component (horizontal angle) of the angle between the visual axis of the subject's eye E and the optical axis of the optical system. For example, the swing mechanism 151 is provided on a stage on which at least the fundus camera unit 2 is mounted and which is moved by the xyz movement mechanism 150. The swing mechanism 151 includes a pulse motor as an actuator, and operates under the control of the main control unit 211.

The tilt mechanism 152 rotates the fundus camera unit 2 in the vertical direction around the pupil of the subject's eye E. This makes it possible to change the vertical component of the angle (elevation/depression angle) between the visual axis of the subject's eye E and the optical axis of the optical system. For example, the tilt mechanism 152 is provided on a stage on which at least the fundus camera unit 2 is mounted and which is moved by the xyz movement mechanism 150. The tilt mechanism 152 includes a pulse motor as an actuator, and operates under the control of the main control unit 211.

Figure 7 shows an explanatory diagram of the angle change operation using the swing mechanism 151 and tilt mechanism 152 according to the embodiment. Figure 7 shows a schematic diagram of the exterior of the ophthalmic device 1 as viewed from the side.

The ophthalmologic device 1 includes a base 1A and a platform 1B mounted on the base 1A so as to be movable in the front-to-back, left-to-right, and up-to-down directions (horizontal directions). A joystick 1C is installed on the platform 1B as an operation unit 240B. For example, the platform 1B is moved front-to-back, left-to-right, and up-to-down on the base 1A by operating the joystick 1C. An operation button as the operation unit 240B is located at the tip of the joystick 1C, and pressing the operation button can be used to instruct the start of imaging.

The base 1A is provided with a chin rest and a forehead rest (not shown). The chin rest and forehead rest secure the subject's (patient's) face to the head unit 1D (housing) (described below) during measurement.

A head unit 1D is provided on the pedestal 1B. The head unit 1D houses the optical system of the fundus camera unit 2, the optical system of the OCT unit 100, and the arithmetic and control unit (control unit 210), and is supported on the pedestal 1B via a swing mechanism 151 and a tilt mechanism 152 that serve as angle change mechanisms. The head unit 1D is configured to be rotatable up and down and left and right on the pedestal 1B by the swing mechanism 151 and the tilt mechanism 152.

For example, the swing mechanism 151 includes a base 1E, a support arm 1F, a pivoting shaft 1G, and a horizontal pivoting section 1H. The base 1E is fixed to the pedestal 1B. The support arm 1F is a rod-shaped member extending in the front-to-back direction. One end of the support arm 1F is fixed to the base 1E, and the other end is positioned on a vertical line passing through the pupil Ep of the subject's eye E. The pivoting shaft 1G is a cylindrical member provided on the other end of the support arm 1F and extending in the up-down direction.

A bearing hole is formed in the horizontal rotation part 1H. By inserting the rotation shaft part 1G into the bearing hole, the horizontal rotation part 1H can rotate relative to the support arm 1F around the rotation axis extending in the vertical direction of the rotation shaft part 1G.

As a result, the swing mechanism 151 can rotate the support arm 1F and tilt mechanism 152 left and right around the pupil Ep by aligning the horizontal position of the rotation axis of the rotation axis portion 1G with the pupil (e.g., pupil center) Ep of the subject's eye E.

The tilt mechanism 152 includes a curved arm 1J.

The curved arms 1J guide the tilting movement of the head unit 1D. The curved arms 1J include, for example, a pair of curved arms that hold the head unit 1D from both sides, and guide the movement of the head unit 1D along the curved arms. Each curved arm is formed in an arc shape with its center of curvature at a central axis extending left and right on an extension of the pivot shaft 1G. One end (lower end) of each curved arm is fixed to the horizontal pivot unit 1H.

As a result, the tilt mechanism 152 can rotate the head unit 1D up and down around the pupil Ep by aligning the position of the center of curvature of the curved arm 1J with the pupil Ep of the subject's eye E.

In some embodiments, a sensor is provided to detect the horizontal angle of the head unit 1D caused by the swing mechanism 151, and the main control unit 211 can obtain the horizontal angle of the head unit 1D. In some embodiments, a sensor is provided to detect the elevation/depression angle of the head unit 1D caused by the tilt mechanism 152, and the main control unit 211 can obtain the elevation/depression angle of the head unit 1D.

In FIG. 6, the main control unit 211 functions as a display control unit and is capable of displaying various types of information on the display unit 240A. For example, the main control unit 211 causes the display unit 240A to display an OCT image formed by the image forming unit 220 (described below) and the results of data processing obtained by the data processing unit 230 (described below).

<Storage unit 212>
The storage unit 212 stores various types of data. The functions of the storage unit 212 are realized by a storage device such as a memory or a storage device. Examples of data stored in the storage unit 212 include control information, image data of fundus images, image data of anterior segment images, OCT data (including OCT images), and information about the subject's eye. Examples of control information include photographing position table information and fixation control information. The photographing position table information and fixation control information will be described later. The subject's eye information includes information about the subject, such as a patient ID and name, identification information for the left eye/right eye, and information about the subject's eye, such as electronic medical record information. The storage unit 212 stores programs for executing various processors (control processor, image formation processor, data processing processor).

When performing fundus photography or OCT measurement, the main controller 211 according to the embodiment performs fixation control according to the distance from the optical axis O of the optical system to the OCT measurement position on the fundus Ef.

Figure 8 shows an explanatory diagram of fixation control according to the embodiment. Figure 8 is a schematic representation of the imaging range (fundus imaging range using the imaging optical system 30, OCT imaging range) from a position corresponding to the optical axis O on the fundus oculi Ef.

The central range including position O1 corresponding to the optical axis O is the central fixation range Fc. In the central fixation range Fc, the main controller 211 controls, for example, the LCD 39 to present an internal fixation to the subject's eye E so that the subject's eye E fixates on the center of the optical axis.

The peripheral range outside the central fixation range Fc is the internal fixation range Fi. In the internal fixation range Fi, the main controller 211 controls, for example, the LCD 39 to present an internal fixation to the subject's eye E so that the subject's eye E fixates on a fixation position in the internal fixation range Fi.

The peripheral range outside the internal fixation range Fi is the first external fixation range Fo1. In the first external fixation range Fo1, the main controller 211 controls, for example, the external fixation unit 23 to turn on the external fixation light source 23-1 so that the subject's eye E fixates on a fixation position in the first external fixation range Fo1, thereby presenting external fixation to the subject's eye E.

The peripheral range outside the first external fixation range Fo1 is the second external fixation range Fo2. In the second external fixation range Fo2, the main controller 211 controls, for example, the external fixation unit 23 to turn on the external fixation light source 23-2 so that the subject's eye E fixates on a fixation position in the second external fixation range Fo2, thereby presenting external fixation to the subject's eye E.

The peripheral range outside the second external fixation range Fo2 is the third external fixation range Fo3. In the third external fixation range Fo3, the main controller 211 controls, for example, the external fixation unit 23 to turn on the external fixation light source 23-3 so that the subject's eye E fixates on a fixation position in the third external fixation range Fo3, thereby presenting an external fixation to the subject's eye E.

The peripheral range outside the third external fixation range Fo3 is the fourth external fixation range Fo4. In the fourth external fixation range Fo4, the main controller 211 controls, for example, the external fixation unit 23 to turn on the external fixation light source 23-4 so that the subject's eye E fixates on a fixation position in the fourth external fixation range Fo4, thereby presenting an external fixation to the subject's eye E.

For example, when OCT measurement is set for a fundus image and an OCT image is acquired, it is desirable to identify the position of the OCT image in the fundus image. When the OCT measurement position is within the central fixation range Fc or internal fixation range Fi, which includes a position corresponding to the measurement optical axis (e.g., the optical axis of the objective lens 22) in the fundus image, the main controller 211 controls the fixation system to present an internal fixation to the subject's eye E. When associating an OCT image acquired by OCT measurement performed with an internal fixation presented to the fundus image, the analyzer 231, described below, can identify the position of the OCT image in the fundus image (e.g., the OCT scan area) based on the fixation position where the fixation light beam is projected.

When the OCT measurement position is outside a predetermined range that includes the position corresponding to the measurement optical axis in the fundus image (e.g., any of the first external fixation range Fo1 to fourth external fixation range Fo4), the main controller 211 controls the fixation system to present external fixation to the subject's eye E. When associating an OCT image acquired by OCT measurement performed while external fixation is presented with the fundus image, the analyzer 231 can identify the position of the OCT image in the fundus image (e.g., the OCT scan area) based on the fixation position where the fixation light beam is projected.

The main control unit 211 according to the embodiment photographs a wide range of the fundus Ef by referencing photographing position table information in which fixation positions corresponding to photographing positions are pre-associated. This makes it possible to observe a wide range of the fundus Ef in detail without changing the orientation of the subject's eye E (direction of the line of sight).

Figure 9 shows an overview of the shooting position table information according to this embodiment.

The photographing position table information includes multiple pieces of fixation position information and multiple pieces of photographing position information. Each piece of fixation position information is pre-associated with the corresponding photographing position information. The fixation position information is, for example, information that represents the projection position of a fixation target on the fundus. The photographing position information is information that represents the photographing position on the fundus that is the subject of photographing using the photographing optical system 30. For example, in the photographing position table information, photographing position information SP-1 is associated with fixation position information FP-1, photographing position information SP-2 is associated with fixation position information FP-2, ..., photographing position information SP-n is associated with fixation position information FP-n (n is an integer greater than or equal to 2).

In this embodiment, the optical axis of the imaging optical system 30 is coupled approximately coaxially with the optical axis of the OCT unit 100. This makes it possible to uniquely identify the OCT imaging position on the fundus measured using the OCT unit 100 from the imaging position on the fundus imaged using the imaging optical system 30. Similarly, it is possible to uniquely identify the imaging position on the fundus imaged using the imaging optical system 30 from the OCT imaging position on the fundus measured using the OCT unit 100.

In some embodiments, the information representing the shooting position is information representing the shooting position itself. In some embodiments, the information representing the shooting position is information representing a shooting area including the shooting position. In this embodiment, the shooting position information is information representing one of the superior area, inferior area, temporal area, or nasal area relative to the fovea. Such shooting position table information is determined in advance taking into account the configuration of the optical system.

The main control unit 211 or the data processing unit 230 can identify the shooting position information from the fixation position information or identify the fixation position information from the shooting position information by referring to the shooting position table information stored in the memory unit 212.

In some embodiments, the memory unit 212 stores multiple pieces of photographing position table information corresponding to the optical information of the subject's eye (e.g., pupil size or axial length). The main control unit 211 or the data processing unit 230 can select photographing position table information corresponding to the optical information of the subject's eye from the multiple pieces of photographing position table information and refer to the selected photographing position table information.

In some embodiments, the main control unit 211 can change the contents of the shooting position table information based on an operation signal corresponding to the user's operation on the operation unit 240B.

In addition, the main control unit 211 according to the embodiment references fixation control information in which information for controlling internal fixation corresponding to the fixation position and information for controlling external fixation are pre-associated. This makes it possible to present internal fixation or external fixation to the subject's eye E depending on the fixation position.

Figure 10 shows an overview of fixation control information according to the embodiment.

The fixation control information includes multiple pieces of fixation position information, multiple pieces of internal fixation control information, and multiple pieces of external fixation control information. Each piece of fixation position information is pre-associated with the internal fixation control information and the external fixation control information. The internal fixation control information is information for controlling internal fixation. Examples of information for controlling internal fixation include information for controlling the on/off state of the LCD 39, the display pixel position of the LCD 39 screen, the light intensity of the fixation light beam, and the timing of switching between on and off for blinking control. The external fixation control information is information for controlling external fixation. Examples of information for controlling external fixation include information for controlling the on/off state of each of the external light sources 23-1 to 23-4, the rotation angle of the fixation light source holding member 23B, the light intensity of each of the external light sources 23-1 to 23-4, and the timing of switching between on and off for blinking control of each of the external light sources 23-1 to 23-4.

For example, fixation control information associates internal fixation control information ifc-1 and external fixation control information ofc-1 with fixation position information FP-1, internal fixation control information ifc-2 and external fixation control information ofc-2 with fixation position information FP-2, and so on, and internal fixation control information ifc-n and external fixation control information ofc-n with fixation position information FP-1 with fixation position information FP-n.

The main control unit 211 can control either the LCD 39 or the external fixation unit 23 according to the fixation position information by referencing the fixation control information stored in the memory unit 212.

In some embodiments, the memory unit 212 stores multiple pieces of fixation control information corresponding to the optical information of the subject's eye (e.g., pupil size or axial length). The main control unit 211 can select fixation control information corresponding to the optical information of the subject's eye or the imaging position from the multiple pieces of fixation control information and refer to the selected fixation control information.

In some embodiments, the main control unit 211 can change the content of the fixation control information based on an operation signal corresponding to the user's operation on the operation unit 240B.

Furthermore, when a montage imaging range is set for the fundus to be imaged, the main controller 211 according to the embodiment sequentially performs OCT imaging for two or more OCT measurement positions (imaging ranges) set to cover the montage imaging range, and forms an OCT montage image from the acquired OCT images. Each time the imaging position is moved, the main controller 211 presents a fixation target at the fixation position corresponding to the OCT measurement position after the move.

In some embodiments, the montage capture is performed by setting a montage capture range for a captured or observed image of the fundus, thereby obtaining an OCT montage image. In some embodiments, the montage capture is performed by setting a montage capture range for an OCT image of the fundus, thereby obtaining a color or near-infrared montage image.

Figure 11 shows an explanatory diagram of the operation of montage photography according to the embodiment. Figure 11 shows a schematic diagram for explaining the operation of montage photography when a montage photography range PR is set for a fundus image IMG acquired using the photographing optical system 30.

The montage photography range PR is set automatically or manually. When the montage photography range PR is set automatically, for example, the data processing unit 230 analyzes the fundus image IMG to identify characteristic regions and specifies the montage photography range PR so that it includes the identified characteristic regions. When the montage photography range PR is set manually, for example, the montage photography range PR is specified based on an operation signal corresponding to the user's operation on the operation unit 240B.

Once the montage imaging range PR is set, the main control unit 211 controls the data processing unit 230 to identify two or more OCT imaging positions (OCT measurement positions). An OCT imaging range is determined corresponding to each OCT imaging position. In Figure 11, nine OCT imaging ranges PA1 to PA9 are identified based on the nine OCT imaging positions.

The main controller 211 or data processor 230 determines the imaging order based on the two or more identified OCT imaging positions. For example, the main controller 211 can determine the imaging order so that imaging is performed at multiple imaging positions in the horizontal direction, and then imaging is performed at adjacent imaging positions in the vertical direction.

The main controller 211 controls the OCT unit 100 and other components to perform OCT imaging sequentially at two or more OCT imaging positions in the determined imaging order. At this time, each time the OCT imaging position is moved, the main controller 211 presents a fixation target at the fixation position corresponding to the new OCT imaging position. Moving the OCT imaging position switches from internal fixation to external fixation, or from external fixation to internal fixation.

The main controller 211 forms an OCT montage image from OCT images acquired through multiple imaging sessions. At this time, the main controller 211 can perform registration processing between the OCT image and the fundus image IMG to form the OCT montage image.

<Image forming unit 220>
As shown in FIG. 6 , the image forming unit 220 includes a processor (e.g., an image forming processor) and forms an OCT image (image data) of the subject's eye E based on the output (sampling results of the detection signals) from the DAQ 130. For example, similar to conventional swept-source OCT, the image forming unit 220 performs signal processing on the spectral distribution based on the sampling results for each A-line to form a reflection intensity profile for each A-line, and then images these A-line profiles and arranges them along the scan line. The signal processing includes noise removal (noise reduction), filtering, FFT (Fast Fourier Transform), etc. When performing other types of OCT, the image forming unit 220 performs known processing appropriate for the type.

<Data Processing Unit 230>
The data processing unit 230 includes a processor (for example, a data processor) and performs image processing and analysis processing on the image formed by the image forming unit 220. At least two of the processor included in the main control unit 211, the processor included in the data processing unit 230, and the processor included in the image forming unit 220 may be configured as a single processor.

The data processing unit 230 performs known image processing, such as interpolation processing that interpolates pixels between tomographic images, to form image data of a three-dimensional image of the fundus oculi Ef or the anterior segment Ea. Note that image data of a three-dimensional image refers to image data in which the positions of pixels are defined using a three-dimensional coordinate system. Image data of a three-dimensional image includes image data consisting of three-dimensionally arranged voxels. This image data is called volume data or voxel data. When displaying an image based on the volume data, the data processing unit 230 performs rendering processing (such as volume rendering or MIP (Maximum Intensity Projection)) on the volume data to form image data of a pseudo-three-dimensional image as viewed from a specific line of sight. This pseudo-three-dimensional image is displayed on a display device such as the display unit 240A.

It is also possible to create stack data of multiple tomographic images as image data for a three-dimensional image. Stack data is image data obtained by arranging multiple tomographic images obtained along multiple scan lines in three dimensions based on the positional relationships of the scan lines. In other words, stack data is image data obtained by expressing multiple tomographic images that were originally defined using separate two-dimensional coordinate systems using a single three-dimensional coordinate system (i.e., embedding them in a single three-dimensional space).

In some embodiments, the data processing unit 230 generates a B-scan image by arranging A-scan images in the B-scan direction. In some embodiments, the data processing unit 230 can perform various rendering operations on the acquired three-dimensional dataset (volume data, stack data, etc.) to generate B-mode images (B-scan images) (longitudinal and axial cross-sectional images) at any cross-section, C-mode images (C-scan images) (transverse and horizontal cross-sectional images) at any cross-section, projection images, shadowgrams, etc. Images of any cross-section, such as B-scan images and C-scan images, are generated by selecting pixels (voxels) on a specified cross-section from the three-dimensional dataset. Projection images are generated by projecting the three-dimensional dataset in a predetermined direction (z direction, depth direction, axial direction). Shadowgrams are generated by projecting a portion of the three-dimensional dataset (e.g., partial data corresponding to a specific layer) in a predetermined direction. Two or more different shadowgrams can be generated by changing the depth range in the layer direction to be integrated. Images taken from the front of the subject's eye, such as C-scan images, projection images, and shadowgrams, are called en-face images.

The data processing unit 230 can construct B-scan images and frontal images (vessel-enhanced images, angiograms) that highlight retinal and choroidal blood vessels based on data collected over time by OCT (e.g., B-scan image data). For example, time-series OCT data can be collected by repeatedly scanning approximately the same area of the subject's eye E.

In some embodiments, the data processing unit 230 compares time-series B-scan images obtained by B-scanning approximately the same area and constructs an enhanced image in which the changed areas are emphasized by converting pixel values of areas where signal intensity has changed into pixel values corresponding to the changes. Furthermore, the data processing unit 230 extracts information for a specified thickness of the desired area from the multiple constructed enhanced images and constructs it as an en-face image to form an OCT angiogram.

The data processing unit 230 includes an analysis unit 231, a montage photography processing unit 231C, and a registration processing unit 231D.

<Analysis section 231>
The analysis unit 231 includes a characteristic part identification unit 231A, a three-dimensional position calculation unit 231B, a montage photography processing unit 231C, and a registration processing unit 231D.

The analysis unit 231 is able to analyze images of the subject's eye E and identify characteristic features depicted in the images. For example, the analysis unit 231 determines the three-dimensional position of the subject's eye E based on the positions of the anterior eye cameras 5A and 5B and the positions of the identified characteristic features. The main control unit 211 aligns the optical system with the subject's eye E by moving the optical system relative to the subject's eye E based on the determined three-dimensional position.

<Characteristic part identification unit 231A>
The characteristic portion identification unit 231A analyzes each of the captured images obtained by the anterior eye cameras 5A and 5B to identify a position in the captured image corresponding to a characteristic portion of the anterior eye Ea (referred to as a characteristic portion). Examples of the characteristic portion include the pupil region of the subject's eye E, the pupil center position of the subject's eye E, the pupil centroid position, the corneal center position, the corneal apex position, the center position of the subject's eye, or the iris. A specific example of processing for identifying the pupil center position of the subject's eye E will be described below.

First, the characteristic part identification unit 231A identifies an image area (pupil area) corresponding to the pupil of the subject's eye E based on the distribution of pixel values (such as brightness values) of the captured image. Since the pupil is generally depicted with a lower brightness than other parts, the pupil area can be identified by searching for an image area with low brightness. At this time, the pupil area may be identified taking into account the shape of the pupil. In other words, the pupil area can be configured to be identified by searching for an image area with a substantially circular shape and low brightness.

Next, the characteristic part identification unit 231A identifies the center position of the identified pupil region. As the pupil is approximately circular as described above, the outline of the pupil region can be identified, and the center position of this outline (an approximate circle or ellipse) can be identified and used as the pupil center position. Alternatively, the center of gravity of the pupil region can be found, and this center position can be identified as the pupil center position.

In addition, even when identifying feature positions corresponding to other characteristic parts, it is possible to identify those feature positions based on the distribution of pixel values in the captured image in the same manner as above.

The characteristic part identification unit 231A is capable of sequentially identifying characteristic positions corresponding to characteristic parts in the images sequentially obtained by the anterior eye cameras 5A and 5B. The characteristic part identification unit 231A may also identify characteristic positions every other arbitrary number of frames or more in the images sequentially obtained by the anterior eye cameras 5A and 5B.

The characteristic part identification unit 231A can identify a characteristic part, such as steam, as a characteristic area for specifying the montage shooting range.

<Three-dimensional position calculation unit 231B>
The three-dimensional position calculation unit 231B identifies the three-dimensional position of the characteristic site as the three-dimensional position of the subject's eye E based on the positions of the anterior-segment cameras 5A and 5B and the characteristic position corresponding to the characteristic site identified by the characteristic site identification unit 231A. As disclosed in Japanese Patent Application Laid-Open No. 2013-248376, the three-dimensional position calculation unit 231B calculates the three-dimensional position of the subject's eye E by applying known trigonometry to the positions (known) of the two anterior-segment cameras 5A and 5B and the positions corresponding to the characteristic sites in the two captured images. The three-dimensional position calculated by the three-dimensional position calculation unit 231B is sent to the main controller 211. Based on the three-dimensional position, the main controller 211 controls the x-y-z movement mechanism 150 so that the positions in the x and y directions of the optical axis of the optical system coincide with the positions in the x and y directions of the three-dimensional position and so that the distance in the z direction is a predetermined working distance.

<Montage shooting processing section 231C>
The montage photography processing unit 231C identifies two or more OCT photography positions based on the size of the montage photography range, which is set automatically or manually, and the size of the OCT photography area (or the fundus photography area using the photography optical system 30). The montage photography processing unit 231C identifies two or more OCT photography positions so that the peripheral area of each OCT image overlaps the peripheral area of an adjacent OCT image. In some embodiments, the size of the OCT photography area is a predetermined size. In some embodiments, the size is determined based on the size of the characteristic area identified when setting the montage photography range.

The functions of the montage shooting processing unit 231C may be configured to be implemented by the control unit 210 (main control unit 211).

<Registration Processing Unit 231D>
The registration processing unit 231D performs registration processing on the two images.

For example, the registration processing unit 231D extracts two or more feature points from each of the two images and aligns the two images so that the positions of the extracted feature points match. For example, the feature points may be blood vessels, blood vessel branches, or lesions. In some embodiments, the registration processing unit 231D performs an affine transformation, a Helmert transformation, or a free transformation.

For example, the registration processing unit 231D extracts one or more feature portions from each of the two images, and aligns the two images using least squares matching (LSM) to minimize the sum of squares of the differences in shading between the two images for the one or more extracted feature portions. In some embodiments, the registration processing unit 231D performs an affine transformation, a Helmert transformation, or a free transformation.

For example, the registration processing unit 231D divides each of the two images into two or more partial images and performs registration based on the above-mentioned feature points or characteristic portions for each partial image. In some embodiments, the registration processing unit 231D performs an affine transformation, a Helmert transformation, or a free transformation for each partial image.

For example, the registration processing unit 231D calculates the degree of correlation between the two images and aligns the two images so that the degree of correlation is equal to or greater than a threshold. In some embodiments, the registration processing unit 231D performs an affine transformation, a Helmert transformation, or a free transformation.

For example, the registration processing unit 231D divides each of the two images into two or more partial images, calculates the degree of correlation between the two images for each partial image, and aligns the two images so that the number of partial images with a degree of correlation equal to or greater than a threshold is maximized. In some embodiments, the registration processing unit 231D performs an affine transformation, a Helmert transformation, or a free transformation.

The registration processing unit 231D performs the above registration processing on two OCT images. Examples of OCT images include projection images (live projection images), shadowgrams, C-scan images, en-face images, and OCT angiograms.

In some embodiments, the registration processing unit 231D performs the above-described registration processing on the fundus image and the OCT image. Examples of fundus images include an observed image of the fundus obtained by the image sensor 35, a photographed image of the fundus obtained by the image sensor 38, and a fundus image acquired in advance. The observed image or photographed image may be a near-infrared image or a color image.

This registration processing unit 231D includes a scan area specification unit 2311D and an overlap determination unit 2312D.

<Scan area specification unit 2311D>
The scan area specifying part 2311D specifies an OCT scan area (position of an OCT image) on a fundus image from the fixation position of the subject's eye E.

Specifically, the scan area specifying unit 2311D refers to the imaging position table information shown in FIG. 9, specifies imaging position information from the fixation position of internal or external fixation, and specifies an imaging area on the fundus oculi Ef from the imaging position information. For example, the imaging area is the upper area, lower area, ear side area, or nose side area of the fundus oculi Ef. The scan area specifying unit 2311D extracts feature points in the specified imaging area. For example, feature points are blood vessels, blood vessel branches, or lesions. In some embodiments, extraction of feature points in the imaging area is performed by the feature site specifying unit 231A.

Next, the scan area identification unit 2311D (or the analysis unit 231) extracts feature points from a projection image created from OCT data (e.g., a live OCT image) of the subject's eye E. The scan area identification unit 2311D identifies an OCT scan area in the fundus image that corresponds to the imaging area so that the feature points extracted in the imaging area match the feature points extracted in the projection image.

<Overlap determination unit 2312D>
The overlap determination unit 2312D determines whether the peripheral areas of two images acquired by montage photography overlap.

The two images to be determined are acquired with a time gap between them, which may result in misalignment due to eye movement. Therefore, the overlap determination unit 2312D according to the embodiment can determine not only whether the peripheral areas of the two images overlap, but also whether the two images are of appropriate (good) image quality. For example, the overlap determination unit 2312D determines whether there is an overlap area between the two images, and if it determines that there is an overlap area, it further calculates the degree of correlation in the overlap area between the two images. If it determines that the degree of correlation in the overlap area is equal to or greater than a threshold, the overlap determination unit 2312D determines that the two images acquired by montage shooting overlap and that the two images are of appropriate image quality.

The size of the peripheral area of the image on which the overlap determination unit 2312D performs the determination process may be a predetermined size, or the area where the two images overlap may be identified and the size of the identified area may be used.

<User Interface 240>
The user interface 240 includes a display unit 240 A and an operation unit 240 B. The display unit 240 A includes the display device 3. The operation unit 240 B includes various operation devices and input devices.

The user interface 240 may include a device that combines display and operation functions, such as a touch panel. In other embodiments, at least a portion of the user interface may not be included in the ophthalmic device. For example, the display device may be an external device connected to the ophthalmic device.

<Communication unit 250>
The communication unit 250 has a function for communicating with an external device (not shown). The communication unit 250 includes a communication interface according to the connection configuration with the external device. Examples of external devices include a server device, an OCT device, a scanning laser ophthalmoscope, a slit lamp ophthalmoscope, an ophthalmic measurement device, and an ophthalmic treatment device. Examples of ophthalmic measurement devices include an eye refraction examination device, a tonometer, a specular microscope, a wavefront analyzer, a perimeter, and a microperimeter. Examples of ophthalmic treatment devices include a laser treatment device, a surgical device, and a surgical microscope. The external device may also be a device (reader) that reads information from a recording medium or a device (writer) that writes information to a recording medium. Furthermore, the external device may also be a hospital information system (HIS) server, a DICOM (Digital Imaging and Communication in Medicine) server, a doctor's terminal, a mobile terminal, a personal terminal, a cloud server, etc.

The optical system from the OCT unit 100 to the objective lens 22 is an example of an "OCT optical system" according to an embodiment. The swing mechanism 151 or the tilt mechanism 152 is an example of an "angle changing mechanism" according to an embodiment. The optical system from the LCD 39 to the objective lens 22, or the external fixation unit 23 is an example of a "fixation system" according to an embodiment. The optical system from the LCD 39 to the objective lens 22 is an example of an "internal fixation system" according to an embodiment. The external fixation unit 23 is an example of an "external fixation system" according to an embodiment. The tilt mechanism is an example of a "first angle changing mechanism" according to an embodiment. The swing mechanism is an example of a "second angle changing mechanism" according to an embodiment.

<Operation>
An example of the operation of the ophthalmologic apparatus 1 will be described.

Figures 14 to 17 show examples of operation of the ophthalmic apparatus 1 according to the embodiment. Figure 14 shows a flow diagram of a first example of operation of the ophthalmic apparatus 1. Figure 15 shows a flow diagram of an example of operation of step S9 in Figure 14. Figures 16 and 17 show flow diagrams of a second example of operation of the ophthalmic apparatus 1.

The storage unit 212 stores a computer program for implementing the processes shown in Figures 14 to 17. The main control unit 211 operates in accordance with this computer program to execute the processes shown in Figures 14 to 17.

First, a first operational example of the ophthalmologic apparatus 1 will be described. In the first operational example, a fixation position is determined from an OCT imaging position specified in a fundus image (e.g., a wide-angle fundus image), and OCT measurement is performed with internal or external fixation presented at the determined fixation position (Figures 14 and 15).

(S1: Alignment)
First, the main control unit 211 performs alignment.

For example, the main controller 211 controls the anterior eye cameras 5A and 5B to capture images of the anterior eye Ea of the subject's eye E substantially simultaneously. The characteristic site identification unit 231A, under control of the main controller 211, analyzes the pair of anterior eye images captured substantially simultaneously by the anterior eye cameras 5A and 5B, and identifies the pupil center position of the subject's eye E as the characteristic site. The three-dimensional position calculation unit 231B determines the three-dimensional position of the subject's eye E. This processing includes calculation processing using trigonometry based on the positional relationship between the pair of anterior eye cameras 5A and 5B and the subject's eye E, as described in JP 2013-248376 A, for example.

The main control unit 211 controls the xyz movement mechanism 150 based on the three-dimensional position of the subject's eye E obtained by the three-dimensional position calculation unit 231B so that the optical system (e.g., the fundus camera unit 2) and the subject's eye E have a predetermined positional relationship. Here, the predetermined positional relationship is a positional relationship that allows the optical system to be used to photograph and examine the subject's eye E. As a typical example, when the three-dimensional position (x coordinate, y coordinate, z coordinate) of the subject's eye E is obtained by the three-dimensional position calculation unit 231B, the position where the x coordinate and y coordinate of the optical axis of the objective lens 22 coincide with the x coordinate and y coordinate of the subject's eye E, respectively, and where the difference between the z coordinate of the objective lens 22 (front lens surface) and the z coordinate of the subject's eye E (corneal surface) is equal to a predetermined distance (working distance) is set as the destination of the optical system.

(S2: Autofocus)
Next, the main control unit 211 starts autofocus.

For example, the main controller 211 controls the focus optical system 60 to project a split index onto the subject's eye E. Under control of the main controller 211, the analysis unit 231 analyzes the observation image of the fundus Ef onto which the split index is projected to extract a pair of split index images and calculate the relative deviation between the pair of split indexes. The main controller 211 controls the focus driver 31A and the focus driver 43A based on the calculated deviation (deviation direction, deviation amount).

(S3: Set OCT imaging position)
Next, the main controller 211 sets an OCT photographing position for a fundus image such as an infrared image (or moving image) of the fundus Ef or a color fundus image of the fundus Ef acquired in advance.

For example, the main controller 211 sets the imaging position specified by the user operating the operation unit 240B while viewing the fundus image as the OCT imaging position. For example, the main controller 211 causes the analysis unit 231 to analyze the fundus image and identify a characteristic part or part of interest, and sets the position in the fundus image corresponding to the identified characteristic part or part of interest as the OCT imaging position.

(S4: Move the optical system)
Next, the main controller 211 performs fixation control so that the fixation light beam is projected onto the fixation position on the fundus Ef corresponding to the OCT imaging position set in step S3. When external fixation is used, the main controller 211 controls the external fixation unit 23, the swing mechanism 151, and the tilt mechanism 152 to change the angle between the direction of the visual axis of the subject's eye E and the direction of the optical axis (measurement optical axis, objective optical axis) of the optical system without changing the orientation of the subject's eye E.

For example, the main controller 211 refers to the imaging position table information in FIG. 9 and identifies the fixation position information from the imaging position information corresponding to the OCT imaging position set in step S3. Next, the main controller 211 refers to the fixation control information in FIG. 10 and references the internal fixation control information and external fixation control information. When presenting an external fixation to the subject's eye E based on the external fixation control information, the main controller 211 controls at least one of the external fixation unit 23, swing mechanism 151, and tilt mechanism 152 based on the external fixation control information to control the emission position of the fixation light beam.

In some embodiments, the main control unit 211 displays predetermined guidance information on the display unit 240A to prompt the user to manually move at least one of the external fixation unit 23, swing mechanism 151, and tilt mechanism 152. For example, the main control unit 211 acquires detection results from sensors provided on each of the external fixation unit 23, swing mechanism 151, and tilt mechanism 152. The main control unit 211 checks from the acquired detection results whether the external fixation unit 23, swing mechanism 151, and tilt mechanism 152 have each been set to the desired state, and it is desirable for the main control unit 211 to continue prompting the user until the predetermined state is reached.

(S5: Present fixation target)
Next, the main controller 211 causes the subject's eye E to present internal fixation or external fixation.

Specifically, the main controller 211 presents an internal fixation or an external fixation to the subject's eye E as described above based on the internal fixation control information or the external fixation control information. When presenting an internal fixation to the subject's eye E, the main controller 211 controls the LCD 39 based on the internal fixation control information, and emits a fixation light beam from the display position of the LCD 39 specified based on the internal fixation control information. When presenting an external fixation to the subject's eye E, the main controller 211 controls the external fixation unit 23 based on the external fixation control information, and emits a fixation light beam from the fixation light source specified based on the external fixation control information.

(S6: Adjust the shooting position)
Next, the main control unit 211 adjusts the photographing position.

Due to eye movement or difficulty in fixating the subject's eye E, the desired imaging position may shift. Therefore, the main controller 211 adjusts the imaging position based on the user's operation on the operation unit 240B. For example, the user may refer to a live OCT image (projection image or en-face image) and operate the operation unit 240B to instruct a change in the imaging position. Examples of adjusting the imaging position include moving the optical system relative to the subject's eye E using the xyz movement mechanism 150, changing the emission position of the fixation light beam (including switching between internal and external fixation), applying an offset voltage to the optical scanner 42, and changing the optical path length difference between the measurement light LS and the reference light LR.

In some embodiments, step S6 is skipped.

(S7: OCT imaging)
Next, the main controller 211 controls the OCT unit 100 and the like to perform OCT imaging at the OCT imaging position determined up to step S5 or the OCT imaging position adjusted in step S6. The main controller 211 controls the image forming part 220 to form an OCT image based on the OCT data obtained by OCT imaging, and controls the data processing part 230 to form a projection image or an en-face image.

(S8: Fundus photography)
Next, the main control unit 211 controls the fundus camera unit 2 to perform photography of the fundus Ef, thereby obtaining a fundus image (for example, a color fundus image) of the fundus Ef.

(S9: Registration process)
Next, the main controller 211 controls the registration processor 231D to execute registration processing between the projection image or en-face image acquired in step S7 and the fundus image acquired in step S8.

Details of step S9 will be described later.

(S10: Display)
Next, the main controller 211 causes the display unit 240A to display a composite image obtained by aligning the projection image or en-face image acquired in step S7 with the fundus image acquired in step S8.

This concludes the first operation example of the ophthalmologic apparatus 1 (END).

The processing of step S9 in Figure 14 is performed according to the flow shown in Figure 15.

(S21: Identifying the photographing area on the fundus from the fixation position)
First, as described above, the scan area specifying unit 2311D refers to the photographing position table information shown in Fig. 9 and specifies photographing position information from the fixation position determined in the processes up to step S4. The scan area specifying unit 2311D specifies the photographing area in the fundus image acquired in step S8 from the specified photographing position information.

(S22: Extract feature points of the photographed area)
Next, the scan area specifying unit 2311D extracts feature points in the imaging area specified in step S21 as described above.

(S23: Extract feature points from OCT image)
Subsequently, the scan area specifying part 2311D (or the analyzing part 231) extracts feature points from the projection image created from the OCT data of the subject's eye E acquired in step S7, as described above.

(S24: Identify OCT scan area)
Next, the scan area identification unit 2311D identifies an OCT scan area corresponding to the shooting area in the fundus image so that the feature points of the fundus image extracted in step S22 match the feature points of the projection image extracted in step S23, as described above.

(S25: Matching process)
Next, the registration processing unit 231D performs registration processing on the projection image based on the OCT data acquired in step S7 and the fundus image acquired in step S8, based on the OCT scan area identified in step S24. In some embodiments, the registration processing unit 231D performs registration processing on the projection image based on the OCT data acquired in step S7 and a fundus image acquired in advance, based on the OCT scan area identified in step S24. In this case, the fundus image acquired in advance may be a fundus image acquired by the ophthalmologic apparatus 1 before executing the flow shown in FIG. 14 or a fundus image acquired in advance by an ophthalmologic apparatus other than the ophthalmologic apparatus 1.

In this embodiment, the projection image and fundus image are aligned (registered) within the OCT scan area identified in step S24, thereby narrowing the image search range and significantly reducing the processing load.

This completes the processing of step S9 in Figure 14 (END).

Next, a second operation example of the ophthalmologic apparatus 1 will be described. In the second operation example, multiple OCT imaging positions are identified from a specified montage imaging range in a fundus image (e.g., a wide-angle fundus image), and OCT imaging is performed sequentially at the identified imaging positions to obtain an OCT montage image (Figures 16-17).

(S31: Alignment)
First, the main control unit 211 performs alignment in the same manner as in step S1.

(S32: Autofocus)
Next, the main control unit 211 starts autofocusing in the same manner as in step S2.

(S33: Set the montage shooting range)
Next, the main control unit 211 sets a montage photography range for a fundus image such as an infrared image (or moving image) of the fundus Ef or a color fundus image of the fundus Ef acquired in advance.

For example, the main control unit 211 sets the imaging range specified by the user operating the operation unit 240B while viewing the fundus image as the montage imaging range. For example, the main control unit 211 causes the analysis unit 231 to analyze the fundus image and identify characteristic areas or areas of interest, and sets an imaging range of a predetermined size that includes the identified characteristic areas or areas of interest as the montage imaging range.

The main controller 211 controls the montage photography processing unit 231C to identify two or more OCT photography positions from the montage photography range set in step S33. As described above, the montage photography processing unit 231C is set so that the OCT photography ranges corresponding to each OCT photography position overlap each other. In addition, the main controller 211 or the data processing unit 230 determines the photography order based on the two or more identified OCT photography positions.

(S34: Move the optical system)
Next, the main control unit 211 performs fixation control in accordance with the shooting order determined in step S33, as in step S4, so that the fixation light beam is projected onto the fixation position on the fundus Ef corresponding to one of two or more OCT shooting positions.

(S35: Present fixation target)
Next, the main controller 211 causes the subject's eye E to present internal fixation or external fixation, similarly to step S5.

(S36: OCT imaging)
Next, similarly to step S7, the main controller 211 controls the OCT unit 100 and the like to perform OCT imaging at the OCT imaging position determined up to step S34. The main controller 211 controls the image forming part 220 to form an OCT image based on the OCT data obtained by OCT imaging, and controls the data processing part 230 to form a projection image or an en-face image.

In some embodiments, between steps S35 and S36, the shooting position is adjusted, similar to step S5.

(S37: Overlap?)
Next, the main controller 211 controls the overlap determination unit 2312D to determine whether or not two or more adjacent projection images (OCT images) acquired by repeatedly executing step S36 overlap each other. Note that if only one projection image is acquired, the process of step S37 is skipped, and the operation of the ophthalmologic apparatus 1 proceeds to step S39.

For example, as described above, the overlap determination unit 2312D determines not only whether the peripheral areas of two or more adjacent projection images overlap, but also whether the two adjacent projection images have appropriate image quality relative to each other.

When it is determined that the peripheral areas of two or more adjacent projection images overlap and that the two adjacent projection images have appropriate image quality (step S37: Y), the operation of the ophthalmologic apparatus 1 proceeds to step S39.

When it is determined that the peripheral areas of two or more adjacent projection images do not overlap, or that the image quality of two adjacent projection images is not appropriate for each other (step S37: N), the operation of the ophthalmologic apparatus 1 proceeds to step S38.

(S38: Finished?)
Next, the main control unit 211 determines whether to end the process. For example, the main control unit 211 determines to end the process when the number of repetitions of step S35 is equal to or greater than a predetermined number. For example, the main control unit 211 determines to end the process when the evaluation value representing the image quality of the projection image determined in step S37 is equal to or less than a predetermined threshold.

When it is determined that the processing should be terminated (step S38: Y), the operation of the ophthalmic apparatus 1 is terminated (END). When it is determined that the processing should not be terminated (step S38: N), the operation of the ophthalmic apparatus 1 proceeds to step S36, and OCT imaging is performed again.

(S39: Registration process)
In step S37, when it is determined that the peripheral areas of two or more adjacent projection images overlap and that the two adjacent projection images have appropriate image quality (step S37: Y), the main control unit 211 controls the registration processing unit 231D to perform registration processing on each of the two or more adjacent projection images, as in step S9.

This forms part of an OCT montage image in which two or more adjacent projection images are aligned.

(S40: Next?)
Next, the main controller 211 determines whether to perform OCT imaging at the next imaging position. For example, the main controller 211 determines whether to perform OCT imaging at the next imaging position in accordance with the imaging order determined in step S34.

If it is determined in step S40 that OCT imaging will be performed for the next imaging position (step S40: Y), the operation of the ophthalmic apparatus 1 proceeds to step S34. As a result, OCT imaging is performed for the next imaging position. If it is determined in step S40 that OCT imaging will not be performed for the next imaging position (step S40: N), the operation of the ophthalmic apparatus 1 proceeds to step S41.

(S41: Fundus photography)
In step S40, when it is determined that OCT imaging will not be performed at the next imaging position (step S40: N), the main controller 211 controls the fundus camera unit 2 to perform imaging of the fundus Ef, as in step S8, thereby acquiring a fundus image of the fundus Ef (for example, a color fundus image).

(S42: Display)
Subsequently, the main controller 211 causes the display unit 240A to display the OCT montage image acquired by repeating steps S36 to S39. In some embodiments, the main controller 211 causes the display unit 240A to display the OCT montage image formed by repeating steps S36 to S39 superimposed on the fundus image acquired in step S41.

This concludes the second operation example of the ophthalmologic apparatus 1 (END).

<Effect>
An ophthalmic apparatus, a control method for the ophthalmic apparatus, and a program according to an embodiment will be described.

An ophthalmic device (1) according to some embodiments includes an optical system (the optical system shown in Figures 1, 2, and 5), an angle change mechanism (swing mechanism 151, tilt mechanism 152), a fixation system (LCD 39, external fixation unit 23), a control unit (210, main control unit 211), an image formation unit (220), and an analysis unit (231). The optical system includes an objective lens (22), an imaging optical system (30), and an OCT optical system (the optical system from the OCT unit 100 to the objective lens 22). The imaging optical system receives light from the subject's eye (E) via the objective lens. The OCT optical system is coupled to the optical path of the imaging optical system, projects measurement light (LS) that has passed through the optical path onto the subject's eye via the objective lens, and detects interference light (LC) between the return light of the measurement light and the reference light (LR). The angle change mechanism tilts the optical system to change the orientation of the optical axis of the optical system. The fixation system projects a fixation light beam toward the subject's eye from a fixation light beam emission position whose relative position with respect to the optical axis is changeable. The control unit changes the angle between the visual axis of the subject's eye and the optical axis based on the OCT measurement position in the image of the subject's eye, projecting the fixation light beam from an emission position corresponding to the OCT measurement position, and performs OCT measurement of the subject's eye by controlling the OCT optical system while the fixation light beam is being projected. The image formation unit forms an OCT image of the subject's eye based on the detection results of the interference light. The analysis unit identifies the position of the OCT image in the image of the subject's eye based on the emission position.

With this configuration, it is possible to perform wide-angle OCT measurement of the subject's eye by controlling the fixation system based on the OCT measurement position in the image of the subject's eye and changing the direction of the optical axis of the optical system using the angle change mechanism. This makes it possible to more easily photograph or measure the subject's eye at a wide angle without the subject having to change the direction of their face.

In some embodiments, the control unit causes the fixation system to project a fixation beam of light for each of two or more OCT measurement positions. The analysis unit identifies the position of the OCT image in the image of the test eye for each of the two or more OCT measurement positions based on the emission position in the fixation system.

With this configuration, it is possible to identify the position of an OCT image in an image of the test eye while controlling at least the fixation system for each of two or more OCT measurement positions. This makes it possible to obtain a composite image of multiple OCT images, such as a montage image.

In some embodiments, the fixation system includes an external fixation system (external fixation unit 23) that projects a fixation light beam from an emission position outside the objective lens that has a known positional relationship with the optical axis toward the subject's eye.

With this configuration, an external fixation system is used to control the fixation system based on the OCT measurement position in the image of the test eye, while the angle change mechanism changes the direction of the optical axis of the optical system, making it possible to perform wide-angle OCT measurement of the test eye.

In some embodiments, the fixation system includes an internal fixation system (LCD 39) and an external fixation system (external fixation unit 23). The internal fixation system includes an internal fixation light source (display pixels on the screen of LCD 39) whose position relative to the optical axis can be changed, and projects a fixation light beam onto the subject's eye via the objective lens. The external fixation system includes external fixation light sources (fixation light sources 23-1 to 23-4) whose position relative to the optical axis can be changed, and projects a fixation light beam from outside the objective lens toward the subject's eye from the position of the external fixation light source that has a known positional relationship with the optical axis.

With this configuration, it is possible to perform wide-angle OCT measurements on the test eye by using an internal fixation system and an external fixation system to control the fixation system based on the OCT measurement position in the image of the test eye, while changing the direction of the optical axis of the optical system with the angle changing mechanism.

In some embodiments, when the OCT measurement position is within a predetermined range (central fixation range Fc or internal fixation range Fi) that includes a position corresponding to the optical axis in the image of the subject's eye, the control unit projects a fixation light beam onto the subject's eye using an internal fixation system, and the analysis unit identifies the position of the OCT image in the image of the subject's eye based on the fixation position where the fixation light beam is projected. When the OCT measurement position is outside a predetermined range (first external fixation range Fo1 to fourth external fixation range Fo4) that includes a position corresponding to the optical axis in the image of the subject's eye, the control unit projects a fixation light beam onto the subject's eye using an external fixation system, and the analysis unit identifies the position of the OCT image in the image of the subject's eye based on the fixation position where the fixation light beam is projected.

With this configuration, it is possible to perform wide-angle OCT measurements on the subject's eye by switching between an internal fixation system and an external fixation system depending on the OCT measurement position and changing the direction of the optical axis of the optical system using the angle change mechanism.

In some embodiments, the control unit projects a fixation beam using an internal fixation system or an external fixation system at each of two or more OCT measurement positions. The analysis unit identifies the position of the OCT image in the image of the test eye for each of the two or more OCT measurement positions based on the fixation position at which the fixation beam is projected.

With this configuration, it is possible to switch between an internal fixation system and an external fixation system depending on the OCT measurement position, and identify the position of an OCT image in the image of the test eye for each of two or more OCT measurement positions. This makes it possible to obtain a composite image of multiple OCT images, such as a montage image.

In some embodiments, the external fixation system is fixed relative to the optical system.

With this configuration, the positional relationship between the external fixation system and the optical axis is constant, making it possible to identify the position of the OCT image in the image of the test eye through simple processing based on the fixation position determined by the external fixation system.

In some embodiments, the angle change mechanism includes a first angle change mechanism (tilt mechanism 152) that changes the angle of the optical axis relative to the horizontal direction in the up-down direction, and a second angle change mechanism (swing mechanism 151) that changes the angle of the optical axis relative to the vertical direction in the left-right direction.

With this configuration, wide-angle OCT measurement can be performed with a simple configuration by controlling the fixation system based on the OCT measurement position in the image of the test eye and changing the orientation of the optical axis of the optical system through tilt and swing operations.

Some embodiments include an operation unit (240B), and the OCT measurement position is set based on the operation performed on the image of the subject's eye using the operation unit.

With this configuration, it is possible to perform OCT measurement at the desired OCT measurement position in the image of the test eye and identify the position of the OCT image in the image of the test eye.

A control method for an ophthalmic device (1) according to some embodiments includes a control step, an image formation step, and an analysis step. The ophthalmic device (1) includes an optical system (the optical system shown in Figures 1, 2, and 5), an angle change mechanism (swing mechanism 151, tilt mechanism 152), and a fixation system (LCD 39, external fixation unit 23). The optical system includes an objective lens (22), an imaging optical system (30), and an OCT optical system (the optical system from the OCT unit 100 to the objective lens 22). The imaging optical system receives light from the subject's eye (E) via the objective lens. The OCT optical system is coupled to the optical path of the imaging optical system, projects measurement light (LS) that has passed through the optical path onto the subject's eye via the objective lens, and detects interference light (LC) between the return light of the measurement light and the reference light (LR). The angle change mechanism tilts the optical system to change the orientation of the optical axis of the optical system. The fixation system projects a fixation light beam toward the subject's eye from a fixation light beam emission position whose relative position with respect to the optical axis is changeable. The control step changes the angle between the visual axis of the subject's eye and the optical axis based on the OCT measurement position in the image of the subject's eye, projecting the fixation light beam from an emission position corresponding to the OCT measurement position, and controls the OCT optical system while the fixation light beam is being projected to perform OCT measurement of the subject's eye. The image formation step forms an OCT image of the subject's eye based on the detection results of the interference light. The analysis step identifies the position of the OCT image in the image of the subject's eye based on the emission position.

This method allows for wide-angle OCT measurement of the subject's eye by controlling the fixation system based on the OCT measurement position in the image of the subject's eye while changing the orientation of the optical axis of the optical system using the angle change mechanism. This makes it possible to more easily photograph or measure the subject's eye at a wide angle without the subject having to change the direction of their face.

In some embodiments, the control step causes a fixation beam to be projected by a fixation system for each of two or more OCT measurement positions. The analysis step identifies the position of an OCT image in the image of the test eye for each of the two or more OCT measurement positions based on the emission position in the fixation system.

This method makes it possible to identify the position of an OCT image in an image of the test eye while controlling at least the fixation system for each of two or more OCT measurement positions. This makes it possible to obtain a composite image of multiple OCT images, such as a montage image.

In some embodiments, the fixation system includes an external fixation system (external fixation unit) that projects a fixation light beam from an emission position outside the objective lens that has a known positional relationship with the optical axis toward the subject's eye.

This method uses an external fixation system to control the fixation system based on the OCT measurement position in the image of the test eye, while changing the direction of the optical axis of the optical system using the angle changing mechanism, making it possible to perform wide-angle OCT measurement of the test eye.

In some embodiments, the fixation system includes an internal fixation system (LCD 39) and an external fixation system (external fixation unit 23). The internal fixation system includes an internal fixation light source (display pixels on the screen of LCD 39) whose position relative to the optical axis can be changed, and projects a fixation light beam onto the subject's eye via the objective lens. The external fixation system includes external fixation light sources (fixation light sources 23-1 to 23-4) whose position relative to the optical axis can be changed, and projects a fixation light beam from outside the objective lens toward the subject's eye from the position of the external fixation light source that has a known positional relationship with the optical axis.

This method uses an internal fixation system and an external fixation system to control the fixation system based on the OCT measurement position in the image of the test eye, while changing the direction of the optical axis of the optical system using the angle change mechanism, making it possible to perform wide-angle OCT measurement of the test eye.

In some embodiments, when the OCT measurement position is within a predetermined range (central fixation range Fc or internal fixation range Fi) that includes a position corresponding to the optical axis in the image of the subject's eye, the control step causes the internal fixation system to project a fixation light beam onto the subject's eye, and the analysis unit identifies the position of the OCT image in the image of the subject's eye based on the fixation position where the fixation light beam is projected. When the OCT measurement position is outside the predetermined range (first external fixation range Fo1 to fourth external fixation range Fo4) that includes a position corresponding to the optical axis in the image of the subject's eye, the control step causes the external fixation system to project a fixation light beam onto the subject's eye, and the analysis unit identifies the position of the OCT image in the image of the subject's eye based on the fixation position where the fixation light beam is projected.

This method makes it possible to perform wide-angle OCT measurements on the subject's eye by switching between an internal fixation system and an external fixation system depending on the OCT measurement position and changing the direction of the optical axis of the optical system using the angle change mechanism.

In some embodiments, the control step projects a fixation beam of light using an internal fixation system or an external fixation system at each of two or more OCT measurement positions. The analysis step identifies the position of an OCT image in the image of the test eye for each of the two or more OCT measurement positions based on the fixation position at which the fixation beam of light is projected.

This method allows the position of an OCT image in an image of the subject's eye to be identified for each of two or more OCT measurement positions while switching between an internal fixation system and an external fixation system depending on the OCT measurement position. This makes it possible to obtain a composite image of multiple OCT images, such as a montage image.

In some embodiments, the external fixation system is fixed relative to the optical system.

With this method, the positional relationship between the external fixation system and the optical axis is constant, making it possible to identify the position of the OCT image in the image of the test eye using simple processing based on the fixation position determined by the external fixation system.

In some embodiments, the angle change mechanism includes a first angle change mechanism (tilt mechanism 152) that changes the angle of the optical axis relative to the horizontal direction in the up-down direction, and a second angle change mechanism (swing mechanism 151) that changes the angle of the optical axis relative to the vertical direction in the left-right direction.

This method allows for wide-angle OCT measurement to be performed with a simple configuration by controlling the fixation system based on the OCT measurement position in the image of the test eye and changing the orientation of the optical axis of the optical system through tilt and swing movements.

In some embodiments, the OCT measurement position is set based on the operation performed on the image of the subject's eye using the operation unit.

This method makes it possible to perform OCT measurement at the desired OCT measurement position in the image of the test eye, thereby identifying the position of the OCT image in the image of the test eye.

In some embodiments, a program causes a computer to execute each step of the control method for an ophthalmic device described above.

This program allows for wide-angle OCT measurement of the subject's eye by controlling the fixation system based on the OCT measurement position in the image of the subject's eye and changing the direction of the optical axis of the optical system using the angle change mechanism. This makes it possible to more easily photograph or measure the subject's eye at a wide angle without the subject having to change the direction of their face.

The embodiment described above is merely one example of the present invention. Anyone wishing to implement the present invention may freely make modifications (omissions, substitutions, additions, etc.) within the scope of the spirit of the present invention.

In some embodiments, a program that causes a computer to execute the ophthalmic device control method is stored in the storage unit 212. Such a program may be stored on any computer-readable recording medium. The recording medium may be an electronic medium that uses magnetism, light, magneto-optical technology, semiconductors, or the like. Typically, the recording medium is a magnetic tape, magnetic disk, optical disk, magneto-optical disk, flash memory, solid-state drive, or the like.

1 Ophthalmic apparatus 2 Fundus camera unit 10 Illumination optical system 22 Objective lens 23 External fixation unit 30 Photography optical system 39 LCD
100 OCT unit 151 swing mechanism 152 tilt mechanism 210 control section 211 main control section 220 image forming section 230 data processing section 231 analysis section 231C montage photography processing section 231D registration processing section E subject eye Ef fundus

Claims (15)

an optical system including an objective lens, an imaging optical system that receives light from the subject's eye via the objective lens, and an OCT optical system that is coupled to an optical path of the imaging optical system, projects measurement light that has passed through the optical path onto the subject's eye via the objective lens, and detects interference light between return light of the measurement light and reference light;
an angle changing mechanism that changes the direction of the optical axis of the optical system by tilting the optical system;
a fixation system that projects a fixation light beam toward the subject's eye from an emission position of the fixation light beam, the emission position of which is changeable relative to the optical axis;
a control unit that changes an angle between the visual axis of the test eye and the optical axis based on an OCT measurement position in the image of the test eye, projects the fixation light beam from the emission position corresponding to the OCT measurement position, and controls the OCT optical system while the fixation light beam is being projected, thereby executing OCT measurement on the test eye;
an image forming unit that forms an OCT image of the subject's eye based on a detection result of the interference light;
an analysis unit that identifies a position of the OCT image in the image of the subject's eye based on the emission position;
Including,
the control unit causes the fixation system to project the fixation light beam onto each of two or more OCT measurement positions;
The ophthalmologic apparatus is configured such that, for each of the two or more OCT measurement positions, the analysis unit identifies a position of the OCT image in the image of the subject's eye based on the emission position in the fixation system . The ophthalmologic apparatus according to claim 1 , wherein the fixation system includes an external fixation system that projects the fixation light beam from the emission position that has a known positional relationship with the optical axis from outside the objective lens toward the subject's eye. an optical system including an objective lens, an imaging optical system that receives light from the subject's eye via the objective lens, and an OCT optical system that is coupled to an optical path of the imaging optical system, projects measurement light that has passed through the optical path onto the subject's eye via the objective lens, and detects interference light between return light of the measurement light and reference light;
an angle changing mechanism that changes the direction of the optical axis of the optical system by tilting the optical system;
a fixation system that projects a fixation light beam toward the subject's eye from an emission position of the fixation light beam, the emission position of which is changeable relative to the optical axis;
a control unit that changes an angle between the visual axis of the test eye and the optical axis based on an OCT measurement position in the image of the test eye, projects the fixation light beam from the emission position corresponding to the OCT measurement position, and controls the OCT optical system while the fixation light beam is being projected, thereby executing OCT measurement on the test eye;
an image forming unit that forms an OCT image of the subject's eye based on a detection result of the interference light;
an analysis unit that identifies a position of the OCT image in the image of the subject's eye based on the emission position;
Including,
The fixation system comprises:
an internal fixation system including an internal fixation light source whose relative position with respect to the optical axis is changeable and which projects the fixation light beam onto the subject's eye via the objective lens;
an external fixation system including an external fixation light source whose relative position with respect to the optical axis is changeable, and which projects the fixation light beam from outside the objective lens toward the subject's eye from a position of the external fixation light source having a known positional relationship with respect to the optical axis;
Including,
when the OCT measurement position is within a predetermined range including a position corresponding to the optical axis in the image of the subject's eye, the control unit causes the internal fixation system to project the fixation light beam onto the subject's eye, and the analysis unit identifies a position of the OCT image in the image of the subject's eye based on the fixation position onto which the fixation light beam is projected;
When the OCT measurement position is outside a predetermined range including a position corresponding to the optical axis in the image of the test eye, the control unit projects the fixation light beam onto the test eye using the external fixation system, and the analysis unit identifies the position of the OCT image in the image of the test eye based on the fixation position where the fixation light beam is projected. an optical system including an objective lens, an imaging optical system that receives light from the subject's eye via the objective lens, and an OCT optical system that is coupled to an optical path of the imaging optical system, projects measurement light that has passed through the optical path onto the subject's eye via the objective lens, and detects interference light between return light of the measurement light and reference light;
an angle changing mechanism that changes the direction of the optical axis of the optical system by tilting the optical system;
a fixation system that projects a fixation light beam toward the subject's eye from an emission position of the fixation light beam, the emission position of which is changeable relative to the optical axis;
a control unit that changes an angle between the visual axis of the test eye and the optical axis based on an OCT measurement position in the image of the test eye, projects the fixation light beam from the emission position corresponding to the OCT measurement position, and controls the OCT optical system while the fixation light beam is being projected, thereby executing OCT measurement on the test eye;
an image forming unit that forms an OCT image of the subject's eye based on a detection result of the interference light;
an analysis unit that identifies a position of the OCT image in the image of the subject's eye based on the emission position;
Including,
The fixation system comprises:
an internal fixation system including an internal fixation light source whose relative position with respect to the optical axis is changeable and which projects the fixation light beam onto the subject's eye via the objective lens;
an external fixation system including an external fixation light source whose relative position with respect to the optical axis is changeable, and which projects the fixation light beam from outside the objective lens toward the subject's eye from a position of the external fixation light source having a known positional relationship with respect to the optical axis;
Including,
the control unit projects the fixation light beam by the internal fixation system or the external fixation system at each of two or more OCT measurement positions;
The analysis unit identifies the position of the OCT image in the image of the subject's eye based on the fixation position where the fixation light beam is projected, for each of the two or more OCT measurement positions. The ophthalmologic apparatus according to any one of claims 2 to 4 , wherein the external fixation system is fixed relative to the optical system. The angle changing mechanism is
a first angle changing mechanism that changes the angle of the optical axis relative to the horizontal direction in the vertical direction;
a second angle changing mechanism that changes the angle of the optical axis relative to the vertical direction in the left-right direction;
The ophthalmic device according to any one of claims 1 to 5 , further comprising: Including an operation unit,
7. The ophthalmologic apparatus according to claim 1 , wherein the OCT measurement position is set based on an operation performed on the image of the subject's eye using the operation unit. an optical system including an objective lens, an imaging optical system that receives light from the subject's eye via the objective lens, and an OCT optical system that is coupled to an optical path of the imaging optical system, projects measurement light that has passed through the optical path onto the subject's eye via the objective lens, and detects interference light between return light of the measurement light and reference light;
an angle changing mechanism that changes the direction of the optical axis of the optical system by tilting the optical system;
a fixation system that projects a fixation light beam toward the subject's eye from an emission position of the fixation light beam that is changeable in relative position with respect to the optical axis,
a control step of changing an angle between the visual axis of the subject's eye and the optical axis based on an OCT measurement position in the image of the subject's eye, projecting the fixation light beam from the emission position corresponding to the OCT measurement position, and controlling the OCT optical system while the fixation light beam is being projected, thereby executing OCT measurement on the subject's eye;
an image forming step of forming an OCT image of the subject's eye based on a detection result of the interference light;
an analyzing step of identifying a position of the OCT image in the image of the subject's eye based on the emission position;
Including,
the control step includes projecting the fixation light beam by the fixation system onto each of two or more OCT measurement positions;
The method for controlling an ophthalmologic apparatus includes: identifying, for each of the two or more OCT measurement positions, a position of the OCT image in the image of the subject's eye based on the emission position in the fixation system . The control method for an ophthalmic apparatus according to claim 8, wherein the fixation system includes an external fixation system that projects the fixation light beam from the emission position that has a known positional relationship with the optical axis from outside the objective lens toward the subject's eye. an optical system including an objective lens, an imaging optical system that receives light from the subject's eye via the objective lens, and an OCT optical system that is coupled to an optical path of the imaging optical system, projects measurement light that has passed through the optical path onto the subject's eye via the objective lens, and detects interference light between return light of the measurement light and reference light;
an angle changing mechanism that changes the direction of the optical axis of the optical system by tilting the optical system;
a fixation system that projects a fixation light beam toward the subject's eye from an emission position of the fixation light beam that is changeable in relative position with respect to the optical axis,
a control step of changing an angle between the visual axis of the subject's eye and the optical axis based on an OCT measurement position in the image of the subject's eye, projecting the fixation light beam from the emission position corresponding to the OCT measurement position, and controlling the OCT optical system while the fixation light beam is being projected, thereby executing OCT measurement on the subject's eye;
an image forming step of forming an OCT image of the subject's eye based on a detection result of the interference light;
an analyzing step of identifying a position of the OCT image in the image of the subject's eye based on the emission position;
Includes
The fixation system comprises:
an internal fixation system including an internal fixation light source whose relative position with respect to the optical axis is changeable and which projects the fixation light beam onto the subject's eye via the objective lens;
an external fixation system including an external fixation light source whose relative position with respect to the optical axis is changeable, and which projects the fixation light beam from outside the objective lens toward the subject's eye from a position of the external fixation light source having a known positional relationship with respect to the optical axis;
Including,
When the OCT measurement position is within a predetermined range including a position corresponding to the optical axis in the image of the subject's eye, the control step causes the internal fixation system to project the fixation light beam onto the subject's eye, and the analysis step specifies a position of the OCT image in the image of the subject's eye based on the fixation position onto which the fixation light beam is projected;
A control method for an ophthalmic device, wherein when the OCT measurement position is outside a predetermined range including a position corresponding to the optical axis in the image of the test eye, the control step projects the fixation light beam onto the test eye using the external fixation system, and the analysis step identifies the position of the OCT image in the image of the test eye based on the fixation position where the fixation light beam is projected. an optical system including an objective lens, an imaging optical system that receives light from the subject's eye via the objective lens, and an OCT optical system that is coupled to an optical path of the imaging optical system, projects measurement light that has passed through the optical path onto the subject's eye via the objective lens, and detects interference light between return light of the measurement light and reference light;
an angle changing mechanism that changes the direction of the optical axis of the optical system by tilting the optical system;
a fixation system that projects a fixation light beam toward the subject's eye from an emission position of the fixation light beam that is changeable in relative position with respect to the optical axis,
a control step of changing an angle between the visual axis of the subject's eye and the optical axis based on an OCT measurement position in the image of the subject's eye, projecting the fixation light beam from the emission position corresponding to the OCT measurement position, and controlling the OCT optical system while the fixation light beam is being projected, thereby executing OCT measurement on the subject's eye;
an image forming step of forming an OCT image of the subject's eye based on a detection result of the interference light;
an analyzing step of identifying a position of the OCT image in the image of the subject's eye based on the emission position;
Includes
The fixation system comprises:
an internal fixation system including an internal fixation light source whose relative position with respect to the optical axis is changeable and which projects the fixation light beam onto the subject's eye via the objective lens;
an external fixation system including an external fixation light source whose relative position with respect to the optical axis is changeable, and which projects the fixation light beam from outside the objective lens toward the subject's eye from a position of the external fixation light source having a known positional relationship with respect to the optical axis;
Including,
the control step includes projecting the fixation light beam by the internal fixation system or the external fixation system onto each of two or more OCT measurement positions;
The analysis step is a control method for an ophthalmic apparatus, in which the position of the OCT image in the image of the test eye is identified based on the fixation position where the fixation light beam is projected for each of the two or more OCT measurement positions. The method for controlling an ophthalmologic apparatus according to any one of claims 9 to 11 , wherein the external fixation system is fixed relative to the optical system. The angle changing mechanism is
a first angle changing mechanism that changes the angle of the optical axis relative to the horizontal direction in the vertical direction;
a second angle changing mechanism that changes the angle of the optical axis relative to the vertical direction in the left-right direction;
The method for controlling an ophthalmic apparatus according to any one of claims 8 to 12, further comprising: The method for controlling an ophthalmologic apparatus according to any one of claims 8 to 13, wherein the OCT measurement position is set based on an operation performed on an image of the subject's eye using an operation unit. A program causing a computer to execute each step of the method for controlling an ophthalmic apparatus according to any one of claims 8 to 14 .