Ophthalmic imaging equipment

Abstract

Provided is an ophthalmologic imaging apparatus that captures an image of an ocular fundus on the basis of return light reflected by the ocular fundus, the apparatus comprising: an optical device unit that, in order to make it possible to reduce the burden on an eye to be inspected, scans measurement light from a light source, causes the measurement light to enter the ocular fundus of the eye to be inspected, and receives the return light reflected by the ocular fundus; and a control unit that controls the optical device unit so that the measurement light is scanned with a predetermined position of the eye to be inspected as a scanning turning point and the measurement light intermittently passes through the scanning turning point.

Description

[Technical Field]

[0001] The present invention relates to an ophthalmologic photographing apparatus for projecting measurement light from a light source onto the fundus of an eye to be examined while scanning the fundus, and receiving reflected light from the fundus to photograph the fundus. [Background technology]

[0002] Conventionally, there has been known an ophthalmologic imaging device that projects measurement light from a light source onto the fundus of an eye to be examined while scanning, and receives reflected light from the fundus to photograph the fundus. For example, Patent Document 1 proposes such an ophthalmologic imaging device.

[0003] Patent document 1 discloses a scanning fundus photography device that scans laser light two-dimensionally to project it onto the fundus, receives reflected light from the fundus, and photographs the fundus, and that blocks harmful reflected light that originates from lens surface reflections of an objective lens composed of multiple lenses, making it possible to photograph the fundus with high image quality. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 045094 Summary of the Invention [Problem to be solved by the invention]

[0005] However, laser light has an effect on the human body, and depending on how it is used, it can lead to excessive strain on the subject's eye, which is a problem.

[0006] SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide an ophthalmologic photographing apparatus that can reduce the burden on the subject's eye. [Means for solving the problem]

[0007] The ophthalmic photographing apparatus of the present invention is an ophthalmic photographing apparatus that includes an optical device unit for scanning measurement light from a light source and making it incident on the fundus of the subject's eye, and for receiving return light reflected by the fundus, and that photographs an image of the fundus based on the return light reflected by the fundus, and is characterized in that it includes a control unit that controls the optical device unit to scan the measurement light using a predetermined position of the subject's eye as a scanning rotation point, and so that the measurement light intermittently passes through the scanning rotation point.

[0008] In addition, in the ophthalmologic photography apparatus of the present invention, the optical device unit further includes a first scanning device that scans the measurement light in a first direction and a second scanning device that scans the measurement light in a second direction, and the control unit controls the first scanning device and the second scanning device to perform a raster scan that repeats scanning in the first direction multiple times while scanning a predetermined range in the second direction once.

[0009] Furthermore, in the ophthalmic photography apparatus of the present invention, the control unit controls the optical device unit so that the scanning range also includes the outside of the passable range that defines the range through which the measurement light can pass and reach the test eye, and makes the measurement light passing through the scanning pivot point intermittent light.

[0010] In addition, in the ophthalmologic photographing apparatus of the present invention, the control unit is further characterized in that it controls the optical device unit to modulate the measurement light output from the light source, and makes the measurement light passing through the scanning rotation point into intermittent light.

[0011] In the ophthalmologic photographing apparatus according to the present invention, the modulation is performed by modulating the measuring light by direct modulation, electro-optic modulation, acousto-optic modulation, or an optical chopper. [Effects of the Invention]

[0012] The embodiments of the present application address one or more of the deficiencies. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram showing an example of the configuration of an ophthalmologic imaging apparatus corresponding to at least one of the embodiments of the present invention. [Figure 2] 1 is an optical diagram showing an example of the configuration of an optical device section in an ophthalmologic imaging apparatus corresponding to at least one of the embodiments of the present invention. [Figure 3] 10 is an explanatory diagram for explaining the path of measurement light when the eye to be examined is observed from the side during photography in the fundus photography device. FIG. [Figure 4] FIG. 1 is an explanatory diagram showing an example of a scanning method in an ophthalmologic imaging apparatus corresponding to at least one of the embodiments of the present invention. [Figure 5] FIG. 1 is an explanatory diagram showing an example of a scanning method in an ophthalmologic imaging apparatus corresponding to at least one of the embodiments of the present invention. [Figure 6] FIG. 1 is a table comparing scanning methods in an ophthalmologic imaging apparatus corresponding to at least one of the embodiments of the present invention. [Figure 7] 10A and 10B are explanatory diagrams showing a scanning method in an ophthalmologic imaging apparatus of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, examples of embodiments of the present invention will be described with reference to the drawings. Note that the various components in the examples of the embodiments described below can be combined as appropriate to the extent that no contradictions arise. Furthermore, the content described as an example of one embodiment may be omitted in other embodiments. Furthermore, the content of operations and processes unrelated to the characteristic parts of each embodiment may be omitted.

[0015] [First embodiment] An example of an ophthalmic imaging apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a block diagram showing an example of the configuration of an ophthalmic imaging apparatus corresponding to at least one of the embodiments of the present invention. As shown in Fig. 1, the ophthalmic imaging apparatus 100 includes an optical device unit 60, a control unit 70, an input device 80, and a display device 90.

[0016] FIG. 2 is an optical diagram showing an example of the configuration of an optical device unit in an ophthalmologic imaging apparatus corresponding to at least one embodiment of the present invention. As shown in FIGS. 1 and 2, the optical device unit 60 is roughly composed of a light projecting optical system 1, a scanning optical system 2, an objective lens optical system 3, and a light receiving optical system 4. Note that the configuration of the optical device unit 60 shown in FIG. 2 is only an example, and a different configuration from that shown in FIG. 2 may be used as long as it can achieve the same functions as the light projecting optical system 1, the scanning optical system 2, the objective lens optical system 3, and the light receiving optical system 4, respectively. Furthermore, the components included in the light projecting optical system 1, the scanning optical system 2, the objective lens optical system 3, and the light receiving optical system 4 of the optical device unit 60 shown in FIG. 1 are only examples of components that can be controlled by the control unit 70, and since this is merely an example, it is naturally possible that other components may be controlled.

[0017] The projection optical system 1 is composed of, for example, a laser light source 10, a projection lens 11, a projection pinhole 12, and a projection focus lens 13. For example, the laser light source 10 uses three laser light sources for R, G, and B colors for color imaging, and an NIR (near-infrared) laser for alignment. Although not shown for simplicity, an optical component is required to overlap the optical axes of these multiple light sources. The laser light from the laser light source 10 passes through the projection lens 11 and enters the projection pinhole 12, which is positioned conjugate with the fundus conjugate plane. The laser light, whose diameter is reduced by the projection pinhole 12, enters the projection focus lens 13. The projection focus lens 13 is movable along the optical axis direction of the light source unit 10 and adjusts the focus of the laser light relative to the fundus 50b of the subject's eye 50. The laser light that passes through the projection focus lens 13 enters an optical path splitting mirror (pupil splitting mirror) 14.

[0018] The scanning optical system 2 is composed of, for example, a first scanning device 20, scanning relay lenses 21 and 22, and a second scanning device 23. The laser light incident on the optical path splitting mirror 14 is reflected therefrom and enters the first scanning device 20. The first scanning device 20 is a device for scanning the laser light in a first direction. The laser light scanned by the first scanning device 20 is incident on the second scanning device 23 via the scanning relay lenses 21 and 22. The second scanning device 23 is a device for scanning the laser light in a second direction perpendicular to the first direction. In this embodiment, to achieve raster scanning of the fundus, which will be described later, scanning by the first scanning device 20 is performed faster than scanning by the second scanning device 23. In this regard, for example, a polygon mirror (rotating polygonal mirror) may be used as the first scanning device 20, and a galvanometer mirror (oscillating mirror) may be used as the second scanning device 23. The laser light reflected by the second scanning device 23 is then incident on the objective lens optical system 3.

[0019] The objective lens optical system 3 is composed of a first lens group 30 and a second lens group 31. The laser light scanned by the first scanning device 20 and the second scanning device 23 passes through the first lens group 30 and the second lens group 31 as measurement light, enters the pupil 50a of the subject's eye 50, and is projected onto the fundus 50b. As a result, the fundus 50b is raster-scanned with the laser light. The laser light projected onto the fundus 50b is reflected by the fundus 50b, and the reflected light travels along the same optical path in the opposite direction and passes through the objective lens optical system 3. Here, the objective lens optical system 3 is configured so that a fundus conjugate plane 32 exists between the first lens group 30 and the second lens group 31, and a fundus image is formed on the fundus conjugate plane 32. The position indicated by the reference symbol 50a is the position of a scanning pivot point, which will be described later.

[0020] The laser light that has passed through the objective lens optical system 3 is scanned in the second and first directions in the scanning optical system 2, and becomes a light beam with a thicker beam than the light beam before entering the scanning optical system 2, and then enters the optical path splitting mirror 14. The optical path splitting mirror 14 is arranged so that its center coincides with the optical axis, and passes reflected light from outside the mirror through the light receiving optical system 4, thereby splitting the optical path into a light projecting optical path and a light receiving optical path. On the other hand, the optical path on the side of the eye to be examined from the optical path splitting mirror 14 is an optical path common to the light projecting optical system 1 and the light receiving optical system 4.

[0021] The light-receiving optical system 4 is composed of, for example, a light-receiving focus lens 40, a light-blocking member 41, a light-receiving pinhole 42, a light-receiving lens 43, a condenser lens 44, and a light-receiving element 45. Light reflected from the fundus 50b that passes through the optical path splitting mirror 14 passes through the light-receiving focus lens 40 and the light-receiving pinhole 42, and then passes through the light-receiving lens 43 and the condenser lens 44 before being received by the light-receiving element 45. The light-receiving element 45, for example, includes light-receiving elements that receive laser light from each of the three colors (R, G, and B) for color photography, and a light-receiving element that receives an IR laser for alignment. Although not shown for simplicity, optical elements are required to separate the laser light of each color to these multiple elements. The light-receiving pinhole 42 is positioned near a position conjugate with the fundus 50b, and the light-shielding member 41 is positioned near a position conjugate with the lens surface of the objective lens optical system 3, blocking harmful reflected light from the lens surface of the objective lens optical system 3 and preventing the generation of a central spot image (false image).

[0022] The light receiving element 45 is composed of, for example, a photodiode, and sends brightness information of each point on the raster-scanned fundus 50b to the control unit 70. The control unit 70 constructs a fundus image from the scanning position of the fundus 50b and the brightness information.

[0023] It is also preferable to provide a diopter adjustment mechanism for adjusting the diopter of the subject's eye 50 in each of the light projecting optical system 1 and the light receiving optical system 4. In this embodiment, the light projecting focus lens 13 of the light projecting optical system 1 and the light receiving focus lens 40 of the light receiving optical system 4 are used as lenses for diopter adjustment, and diopter adjustment can be performed by moving the light projecting focus lens 13 and the light receiving focus lens 40 in conjunction with each other along the optical axis. Similarly, the light blocking member 41 also moves in conjunction with the light projecting focus lens 13 and the light receiving focus lens 40 along the optical axis.

[0024] The control unit 70 includes, for example, a drive control unit 71, an image generation unit 72, and a storage unit 73. The drive control unit 71 has a function of executing control of each unit controlled by the optical device unit 60. Examples of units controlled by the optical device unit 60 include the laser light source 10, the light projecting focus lens 13, the first scanning device 20, the second scanning device 23, the light receiving focus lens 40, the light blocking member 41, and the light receiving element 45. The image generation unit 72 has a function of constructing a fundus image from information on received data corresponding to each scanning position of the fundus 50b received by the light receiving element 45. The storage unit 73 has a function of storing various programs for drive control and also has a function of storing data of the fundus image generated by the image generation unit 72.

[0025] The input device 80 has a function of receiving input operations from the operator of the ophthalmologic imaging apparatus 100. Examples of the input device 80 include input devices such as a mouse, keyboard, and touch panel, as well as operation buttons when configured as a dedicated device. The display device 90 has a function of displaying fundus images generated by the image generation unit 72, etc.

[0026] Next, a scanning method of a comparative example, which is a prerequisite for explaining the scanning method of the present embodiment, will be described. FIG. 7 is an explanatory diagram showing a scanning method in an ophthalmologic imaging apparatus of the comparative example. Hereinafter, the range through which light rays (measurement light) from a light source can pass and reach the subject's eye is sometimes referred to as the "passable range," the range through which the measurement light is scanned by the scanning device is sometimes referred to as the "scanning range," and the range to be photographed is sometimes referred to as the "photographing range." Here, the passable range can be set by the lens barrel, aperture, lens diameter, and the like that constitute the optical device unit 60. In the comparative example, the photographing range and the scanning range coincide with each other, and the photographing range and the scanning range are included in the passable range. As described above, in raster scanning, high-speed scanning in the first scan (horizontal direction) is repeatedly performed within the scanning range while low-speed scanning in the second direction (vertical direction) is performed once. When considering efficient fundus photography using raster scanning, a setting like that of the comparative example in which the scanning range coincides with the photographing range is effective, but the following problems are of concern.

[0027] Fig. 3 is an explanatory diagram illustrating the path of the measurement light when the subject's eye is observed from the side during photography using a fundus photography device. To photograph a predetermined range of the fundus of the subject's eye, it is necessary to change the angle of incidence of the measurement light relative to the subject's eye for scanning. However, as shown in Fig. 3, even when the angle of incidence of the measurement light is changed, a scanning rotation point, which is a point through which the measurement light passes, is almost always generated. Therefore, in a method that always scans within the passable range as in the comparative example, the measurement light continues to be irradiated onto this scanning rotation point. As a result, the burden on the pupil where the scanning rotation point is located and the cornea, iris, and crystalline lens around it is likely to be large.

[0028] Therefore, the first embodiment is characterized in that the outside of the passable range is included in the scanning range, so that the measurement light passing through the scanning turning point is made into intermittent light.

[0029] FIG. 4 is an explanatory diagram showing an example of a scanning method in an ophthalmologic imaging apparatus corresponding to at least one embodiment of the present invention. The scanning method shown in FIG. 4 illustrates overscanning, in which the outside of the passable range of the measurement light is also scanned. If the direction from right to left is the first direction, which is the scanning direction of the first scanning device 20, and the direction from top to bottom is the second direction, which is the scanning direction of the second scanning device 23, the two scanning directions are orthogonal, and the scanning range is rectangular. Furthermore, in this embodiment, as shown in FIG. 4, a scanning range is also set outside the passable range. The measurement light (shown by the solid line) scanning within the passable range is incident on the test eye as in the comparative example, but the measurement light (shown by the dashed line) scanning outside the passable range is not incident on the test eye, so the time spent scanning outside the passable range is non-irradiation time at the scanning pivot point.

[0030] Here, various configurations are conceivable for extending the scanning range beyond the passable range. For example, the optical device may be designed so that the scanning range of the first scanning device 20 extends to a predetermined range outside the range where light does not enter the scanning relay lens 21 or the first lens group 30, and / or the optical device may be designed or adjusted so that the scanning range of the second scanning device 23 extends to a predetermined range outside the range where light does not enter the first lens group 30. When a galvanometer mirror is used as the second scanning device 23, the optical device may be designed to provide overscanning in the second scanning direction and the control unit 70 may uniformly control the optical device, or the control unit 70 may variably control the swing angle of the galvanometer mirror to switch overscanning on and off. Another possible configuration is one in which the measurement light in the entire scanning range of the first scanning device 20 passes through the scanning relay lens 21, but a portion of the measurement light is blocked between the scanning relay lenses 21 and 22 to limit the passable range, thereby setting the time spent scanning outside the passable range to the non-irradiation time at the scanning pivot point. Alternatively, a configuration is conceivable in which the measurement light passes through the entire scanning range up to the scanning optical system 2 in front of the first lens group 30, but the objective lens optical system 3 after the first lens group 30 blocks part of the measurement light emitted therefrom to limit the passable range, thereby setting the time spent scanning outside the passable range to the non-irradiation time at the scanning turning point. Naturally, these are merely examples of configurations, and the present embodiment is not limited to these.

[0031] As described above, one aspect of the first embodiment is an ophthalmologic imaging device that scans measurement light from a light source and makes it incident on the fundus of the test eye, receives the return light reflected by the fundus, and captures an image of the fundus based on the return light reflected by the fundus, and is equipped with an optical device unit that scans the measurement light using a predetermined position on the test eye as a scanning rotation point, and a control unit that controls the optical device unit so that the measurement light passes through the scanning rotation point intermittently, and the control unit controls the optical device unit so that the scanning range also includes the outside of the passable range that defines the range through which the measurement light can pass and reach the test eye, and makes the measurement light passing through the scanning rotation point intermittent light, thereby making it possible to reduce the burden on the test eye during imaging more than in the comparative example.

[0032] That is, assuming a 2:1 ratio between the time (area) spent scanning within the passable range and the time (area) spent scanning outside the passable range, if the scanning time spent scanning within the passable range is the same as that spent photographing in the comparative example, the time required for photographing will be 1.5 times longer than that of the comparative example. According to this method, even if the total power of the measurement light irradiated near the scanning pivot point is the same, it is possible to reduce the irradiation power per unit time relative to the measurement time, thereby reducing the burden on the subject's eye during photographing. The measurement light in the comparative example is treated as a continuous wave, and therefore must be evaluated based on the limit value for continuous wave devices in ISO 15004-2, the standard for optical hazards in ophthalmic optical instruments. In contrast, in an overscan configuration like the first embodiment, if the continuous irradiation time is 0.25 seconds or less, it is treated as a pulsed device, and evaluation is based on the limit value for pulsed devices in ISO 15004-2, the standard for ophthalmic optical instruments. In "ISO 15004-2," the limit values ​​for pulsed devices are more relaxed than the limit values ​​for continuous wave devices. Therefore, the method of the first embodiment not only reduces the burden on the subject's eye, but also has the advantage of making it easier to meet the standards for ophthalmic optical devices for photographing the fundus.

[0033] [Second embodiment] An example of an ophthalmologic imaging apparatus according to a second embodiment of the present invention will be described below with reference to the drawings. Note that the configuration of the ophthalmologic imaging apparatus in this second embodiment is the same as that of the first embodiment described with reference to Figures 1 and 2, and therefore a description thereof will be omitted.

[0034] Here, this second embodiment is characterized in that the shooting range and the scanning range are the same as in the comparative example, but the measurement light output from the light source is modulated to make the measurement light passing through the scanning turning point intermittent light.

[0035] FIG. 5 is an explanatory diagram showing an example of a scanning method in an ophthalmologic imaging apparatus corresponding to at least one embodiment of the present invention. The scanning method shown in FIG. 5 illustrates a state in which the measurement light output from the laser light source 10 is modulated into intermittent light, which can be called a pulsed light, in which the irradiation period and non-irradiation period change periodically. When the scanning direction of the first scanning device 20 is defined as the first direction, which is a scanning direction from right to left, and the scanning direction of the second scanning device 23 is defined as the second direction, which is a scanning direction from top to bottom, are set to intersect at right angles, the scanning range becomes rectangular. As shown in FIG. 5, unlike the first embodiment, the scanning range of the second embodiment is within the range through which the measurement light can pass. However, by using a measurement light modulated into a pulsed light, the measurement light passing through the scanning pivot point becomes intermittent light.

[0036] Any means capable of modulating the measurement light into a pulsed form is acceptable. Modulation methods include direct modulation, which directly controls the current flowing through the laser light source 10, as well as external modulation methods such as electro-optical modulators (EOMs), acousto-optical modulators (AOMs), and optical choppers. Regarding the modulation frequency, the standard for optical hazards in ophthalmic optical instruments, ISO 15004-2, requires that the pulse duration be less than 0.25 seconds, i.e., 4 Hz or greater. It is also preferable to determine the modulation frequency based on the balance between the number of samples and the imaging time. To perform sampling in a single imaging session, at least one on-period (illumination period) must occur at each sampling point, and there must also be an off-period (non-illumination period) between adjacent sampling points. In other words, at least one period must elapse at each sampling point. For example, if the imaging conditions are 3,000 scans and 3,000 points are sampled per scan, a total of 9 million points must be sampled. Assuming an imaging time of 0.4 seconds, it is preferable to modulate the frequency to 22.5 MHz or higher in order to sample thoroughly in one imaging session. Furthermore, it is also possible to set the frequency to match the sampling rate of the sampling board (for example, 240 MHz).

[0037] As described above, one aspect of the second embodiment is an ophthalmologic imaging device that includes an optical device unit for scanning measurement light from a light source and making it incident on the fundus of the test eye, and receiving the return light reflected by the fundus, and captures an image of the fundus based on the return light reflected by the fundus, and includes a control unit that controls the optical device unit to scan the measurement light using a predetermined position on the test eye as a scanning rotation point, and causes the measurement light to pass through the scanning rotation point intermittently, and the control unit controls the optical device unit to modulate the measurement light output from the light source, making the measurement light passing through the scanning rotation point intermittent light, thereby making it possible to reduce the burden on the test eye during imaging compared to the comparative example.

[0038] In other words, if modulation is performed so that the duty ratio (ratio of irradiation period in one cycle) is 0.5, the irradiation time of the measurement light can be halved compared to when modulation is not performed under the same conditions, thereby reducing the irradiation energy at the scanning rotation point and reducing the burden on the subject's eye during imaging.

[0039] Fig. 6 is a table comparing scanning methods in an ophthalmologic imaging apparatus according to at least one embodiment of the present invention, which compares the comparative example shown in Fig. 7 with the overscanning described in the first embodiment and the laser modulation described in the second embodiment.

[0040] As shown in Fig. 6, when the comparative example is compared with the overscanning adopted in the first embodiment, the irradiation power is the same, but the measurement time is 1.5 times longer, so it is possible to reduce the irradiation power per unit time. Under the conditions exemplified as the comparative example in Fig. 6, the irradiation power is 127.3 (mW / cm 2 ) which is the limit of the irradiation power of continuous wave equipment, 100 (mW / cm 2 ), and therefore is deemed non-compliant. In contrast, in the first embodiment where overscanning is performed using a laser light source under the same conditions, the irradiation energy per image is 6.4 × 10 -2 (J / cm 2 ), which is the limit of the irradiation energy per shot for pulsed equipment, 1.5 (J / cm 2 ) or less, which means that it complies with the standards for pulse equipment.

[0041] Furthermore, as shown in Figure 6, when comparing the comparative example with the laser modulation adopted in the second embodiment, when the duty ratio is 0.5, the laser modulation can reduce the irradiation energy by half compared to the comparative example. In the case of the second embodiment, the irradiation energy per image is 3.2 x 10 -2 (J / cm 2), which is the limit of the irradiation energy per shot for pulsed equipment, 1.3 (J / cm 2 ) or less, which means that it complies with the standards for pulse equipment. [Explanation of symbols]

[0042] 100 Ophthalmic imaging device 1. Projection optical system 2. Scanning optical system 3 Objective lens optical system 4 Light receiving optical system 10 Laser light source 11 Projection lens 12 Light projection pinhole 13 Light projection focus lens 14 Optical path splitting mirror 20 Horizontal scanning device 21 Scanning relay lens 22 Scanning relay lens 23 Vertical scanning device 30 First lens group 31 Second lens group 32 Fundus conjugate plane 40 Receiving focus lens 41 Light blocking member 42 Light receiving pinhole 43 Receiving lens 44 Condenser Lens 45 Photodetector 50 Examined eye 50a Pupil (position of scanning pivot point) 50b Fundus 60 Optical equipment section 70 Control Unit 71 Drive control unit 72 Image generation unit 73 Memory section 80 Input Device 90 Display device

Claims

1. An ophthalmologic imaging device comprising an optical device unit for scanning measurement light from a light source to make it incident on a fundus of an eye to be examined and receiving return light reflected by the fundus, and for capturing an image of the fundus based on the return light reflected by the fundus, a control unit that controls the optical device unit to scan the measurement light with a predetermined position of the subject's eye as a scanning rotation point and to cause the measurement light to intermittently pass through the scanning rotation point; the optical device unit includes a first scanning device that scans the measurement light in a first direction and a second scanning device that scans the measurement light in a second direction; the control unit controls the first scanning device and the second scanning device to perform a raster scan in which scanning in the first direction is repeated a plurality of times while scanning a predetermined range in the second direction once, Further, the control unit controls the optical device unit so that the outside of a passable range that defines a range through which the measurement light can pass and reach the eye to be examined is also included in the scanning range in the first direction and / or the second direction, and makes the measurement light passing through the scanning turning point into intermittent light. An ophthalmic photographing apparatus characterized by the above.

2. The control unit controls the optical device unit to modulate the measurement light output from the light source, and makes the measurement light passing through the scanning pivot point an intermittent light.

2. An ophthalmologic photographing apparatus according to claim 1.

3. The modulation is performed by modulating the measurement light using direct modulation, electro-optic modulation, acousto-optic modulation, or an optical chopper.

3. An ophthalmologic photographing apparatus according to claim 2.

Images