JP2016028687A - Scan type laser ophthalmoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scan type laser ophthalmoscope capable of acquiring a good front image of an eye to be examined.SOLUTION: A scan type laser ophthalmoscope 1 includes: an irradiation optical system 10 having a laser beam emitting part 11, a scan part 16, and an objective lens system 17; a light receiving optical system 20 having a pinhole plate 23; and a perforated mirror 13 for branching optical paths L1 and L2 of the irradiation optical system 10 and the light receiving optical system 20. The scan type laser ophthalmoscope 1 acquires an image of ocular fundus based on a light reception signal from a light receiving element 25 of the light receiving optical system 20. The scan type laser ophthalmoscope 1 further includes a light shielding member 22 disposed at a position deviating from a position conjugate with the ocular fundus of the eye to be examined in the optical path between the perforated mirror 13 and the light receiving element 25 that transmits the light from the ocular fundus conjugate surface, and shields at least part of the reflection light from a lens surface 17a of the objective lens system 17. The light receiving element 25 receives the light from the ocular fundus that has passed through the pinhole plate 23 and the light shielding member 22.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a scanning laser ophthalmoscope that captures a front image of an eye to be examined.

  2. Description of the Related Art Conventionally, a scanning laser ophthalmoscope is known as an apparatus that captures a front image of an eye to be examined. Patent Document 1 describes an apparatus that obtains an image of the fundus by scanning laser light emitted from a light source on the fundus and receiving the fundus reflection light. In this type of apparatus, an opening (confocal stop) is provided at a position conjugate with the fundus in front of the light receiving element, and the incidence of noise light on the light receiving element is suppressed by the opening.

JP 2012-130763 A

  By the way, in the scanning laser ophthalmoscope, the tissue before and after the condensing position can be drawn by detecting the scattered light of the laser light scattered before and after the condensing position of the laser light on the observation surface of the eye to be examined. More specifically, in addition to a method of making the size of the confocal aperture relatively large or using a ring aperture, so-called retro photography using an eccentric aperture (for example, see JP 2009-95632 A), etc. There can be.

  However, according to the study of the present inventor, it has been found that the above attempt results in an increase in the possibility that noise light from the inside of the optical system is received by the light receiving element.

  This indication is made in view of the problem of the above-mentioned conventional technology, and makes it a technical subject to provide the scanning laser ophthalmoscope which can obtain the good front picture of the eye to be examined.

  In order to solve the above problem, a scanning laser ophthalmoscope according to the first aspect of the present disclosure includes an irradiation light source, and scanning means for scanning the fundus of the eye to be examined with laser light emitted from the irradiation light source. An objective lens system for guiding the laser light scanned by the scanning means to the fundus of the eye to be examined, and an irradiation optical system for irradiating the fundus with the laser light, and a position conjugate with the fundus of the eye to be examined And the objective lens system is used in common with the irradiation optical system, and the light from the fundus caused by the laser light irradiated by the irradiation optical system is used as the first light shielding unit. A light receiving optical system for receiving light through the light receiving element, and an optical path branching member for branching the light path of the irradiation optical system and the light receiving optical system, and based on a light receiving signal from the light receiving element, image A scanning laser ophthalmoscope that is provided at a position deviating from a position conjugate with the fundus of the eye to be examined in an optical path between the optical path branching member and the light receiving element, and transmits light from a fundus conjugate plane. A second light-shielding part that shields at least part of the reflected light from the lens surface of the objective lens system, and the light from the fundus that has passed through the first light-shielding part and the second light-shielding part is The light receiving element receives light.

  Further, the scanning laser ophthalmoscope according to the second aspect of the present disclosure includes an irradiation light source, a scanning unit for scanning a laser beam emitted from the irradiation light source on an observation surface of the eye to be examined, and the scanning unit. An objective lens system for guiding the scanned laser light to the observation surface, and disposed at a position conjugate with the irradiation optical system for irradiating the observation surface with laser light and the observation surface of the eye to be examined. And the objective lens system is used in common with the irradiation optical system, and the light from the observation surface by the laser light irradiated by the irradiation optical system is passed through the first light blocking unit. A light receiving optical system for receiving light by the light receiving element, and an optical path branching member for branching the optical path of the irradiation optical system and the light receiving optical system, and an image of the observation surface based on a light receiving signal from the light receiving element Get scanning A laser ophthalmoscope, provided at a position deviating from a position conjugate with the observation surface of the eye to be examined in an optical path between the optical path branching member and the light receiving element, and passes light from a surface conjugate with the observation surface And a second light-shielding part that shields at least part of the reflected light from the lens surface of the objective lens system, and the light from the observation surface that has passed through the first light-shielding part and the second light-shielding part Is received by the light receiving element.

  According to the present disclosure, a good front image of the eye to be examined can be obtained.

It is a schematic block diagram of the optical system which the scanning laser ophthalmoscope 1 of 1st Embodiment has. FIG. 2 is an enlarged view showing an optical path from a perforated mirror 13 to a light receiving element 25 in the optical system shown in FIG. 1. FIG. 2 is a diagram showing an optical path of reflected light on a lens surface 17a of an objective lens system 17 in the optical system shown in FIG. It is the figure which looked at the light shielding member 22 of 1st Embodiment from the optical axis direction. It is a schematic block diagram of the optical system which the scanning laser ophthalmoscope 100 of 2nd Embodiment has. It is the table | surface which showed the wavelength range of the light received by three light receiving elements, and the use as an example of the light of each wavelength range. It is the figure which looked at the light shielding members 210 and 220 of 2nd Embodiment from the optical axis direction. It is a schematic block diagram of the optical system which the scanning laser ophthalmoscope 200 of 3rd Embodiment has. It is a graph which shows the spectral characteristics of the light-shielding parts 211a and 221a. It is the figure which showed the optical system in the 1st modification of 1st Embodiment. It is the figure which showed the optical system in the 2nd modification of 1st Embodiment.

  Hereinafter, a scanning laser opthalmoscope (SLO) according to an exemplary embodiment of the present disclosure will be described with reference to the drawings. The scanning laser ophthalmoscope according to the present disclosure is an apparatus that acquires a front image of the fundus by scanning laser light on the fundus and receiving return light of the laser light from the fundus. As an imaging method of the scanning laser ophthalmoscope 1, for example, a fluorescent imaging method is known in addition to an imaging method using fundus reflection light. The scanning laser ophthalmoscope may be an apparatus integrated with another ophthalmologic apparatus such as an optical coherence tomography (OCT) or a perimeter.

<First Embodiment>
First, a first embodiment will be described with reference to FIGS. FIG. 1 shows an optical system of a scanning laser ophthalmoscope 1 according to the first embodiment. In the first embodiment, a case will be mainly described in which an image of the fundus oculi Er is captured using light reflected by the fundus oculi Er. That is, the fundus image can be taken based on the fundus reflection light. However, the scanning laser ophthalmoscope 1 according to the first embodiment may be used for fluorescence imaging.

  As an example, the scanning laser ophthalmoscope 1 includes an irradiation optical system 10 and a light receiving optical system 20. The irradiation optical system 10 irradiates the fundus Er of the eye E with laser light (illumination light). In the first embodiment, the irradiation optical system 10 includes a laser light emitting unit 11, a condenser lens 12, a perforated mirror 13, a lens 14, a lens 15, a scanning unit 16, and an objective lens system 17.

  The laser beam emitting unit 11 is a light source of the irradiation optical system 10. The laser light emitting unit 11 may be a light source that emits laser light (for example, a laser diode (LD), a super luminescent diode (SLD), or the like). In the first embodiment, the laser light emitting unit 11 will be described as having a light source that emits monochromatic light (more specifically, infrared light). However, it is not necessarily limited to this. For example, the laser beam emitting unit 11 may have a plurality of light sources. In this case, the laser beam emitting unit 11 may be configured to emit light of a plurality of colors simultaneously or selectively. Further, the wavelength of the light emitted from the laser light emitting unit 11 is not limited to the infrared region, and may be a wavelength in the visible region, for example.

  The laser light emitted from the laser light emitting unit 11 is guided to the fundus oculi Er through a path indicated by a solid line in FIG. That is, the laser beam from the laser beam emitting unit 11 passes through the condenser lens 12, passes through the opening 13 a formed in the perforated mirror 13, passes through the lens 14 and the lens 15, and then travels toward the scanning unit 16. The laser light reflected by the scanning unit 16 passes through the objective lens system 17 and is then applied to the fundus Er of the eye E. As a result, light reflected and scattered by the fundus Er is emitted from the pupil.

  In the first embodiment, the lens 14 is configured to be movable in the direction of the optical axis L1 by the drive mechanism 14a. Depending on the position of the lens 14, the diopter of the irradiation optical system 10 and the light receiving optical system 20 changes. In the first embodiment, the diopter error of the eye E is corrected (reduced) by adjusting the position of the lens 14. As a result, the condensing position of the laser light can be adjusted to the observation site (for example, the retina surface) of the fundus oculi Er.

  The scanning unit 16 is a unit that changes the traveling direction of the laser light guided from the laser light emitting unit 11 (deflects the laser light) in order to scan the laser light on the fundus. In the first embodiment, the scanning unit 16 includes a resonant scanner 16a and a galvanometer mirror 16b. In the first embodiment, main scanning of laser light is performed in the X direction by the resonant scanner 16a. Further, the sub scanning of the laser beam is performed in the Y direction by the galvanometer mirror 16b. As the scanning unit 16, for example, an acousto-optic device (AOM) that changes the traveling (deflection) direction of light may be used in addition to a reflection mirror (galvano mirror, polygon mirror, resonant scanner).

  The objective lens system 17 forms a turning point P around which the laser light passed through the scanning unit 16 is turned. In the first embodiment, the turning point P is on the optical axis L3 of the objective lens system 17, and with respect to the objective lens system 17, the scanning unit 16 (for example, an intermediate point between the resonant scanner 16a and the galvanometer mirror 16b) and optical. Are formed at conjugate positions. The laser light that has passed through the scanning unit 16 passes through the objective lens system 17 and is irradiated to the fundus Er through the turning point P. For this reason, the laser light that has passed through the objective lens system 17 is turned around the turning point P as the scanning unit 16 operates. As a result, in the example of FIG. 1, the laser light is scanned two-dimensionally on the fundus Er. In addition, since the turning point P of the laser beam and the pupil position of the eye E are matched in advance, vignetting in the iris is suppressed and the laser beam is guided well to the fundus Er. The laser light applied to the fundus Er is reflected at a condensing position (for example, the retina surface). Further, the laser light is scattered by the tissues before and after the condensing position. Reflected light and scattered light from the fundus Er are respectively emitted from the pupil as parallel light.

  In FIG. 1, the objective lens system 17 is illustrated as a single objective lens for convenience, but is not limited thereto. The objective lens system 17 may be composed of a plurality of lenses. In addition, a cemented lens in which a plurality of lenses are bonded together, an aspherical lens, or the like may be used for the objective lens system 17.

  Next, the light receiving optical system 20 will be described. The light receiving optical system 20 receives light from the fundus oculi Er by the laser light irradiated by the irradiation optical system 10 to the light receiving element 25 via the first light blocking portion (in the first embodiment, the pinhole plate 23). Let Light from the fundus Er accompanying the laser light from the irradiation optical system 10 is received by the light receiving element 25. The light receiving optical system 20 according to the first embodiment includes a lens 21, a light shielding member 22 (an example of a second light shielding portion), a pinhole plate 23, a lens 24, and a light receiving element 25. The pinhole plate 23 is disposed at a position conjugate with the fundus Er and functions as a confocal stop as will be described later. Further, the light receiving optical system 20 shares the members arranged from the objective lens system 17 to the perforated mirror 13 with the irradiation optical system 10. As a result, in the first embodiment, the optical path from the eye E to the perforated mirror 13 is formed as a common part of the irradiation optical system 10 and the light receiving optical system 20.

  When laser light is irradiated on the fundus Er of the eye E, the light reflected by the fundus Er is guided to the light receiving element 25 through a light path indicated by a broken line in FIG. First, as for the light from the fundus, the light extracted from the pupil traces the irradiation optical system 10 in the reverse direction and irradiates the perforated mirror 13.

  In the first embodiment, the perforated mirror 13 is an optical path branching member that branches light from the fundus Er that passes through the common optical path of the irradiation optical system 10 and the light receiving optical system 20. By the perforated mirror 13, the light from the fundus Er is branched into a light receiving side optical path (here, an optical path along the optical axis L2 direction) and a light source side optical path (here, an optical path along the optical axis L1). As shown in FIG. 2, in the first embodiment, the perforated mirror 13 has an opening 13a and a mirror 13b. The opening 13 a is formed at the center of the perforated mirror 13. The mirror part 13b is formed around the opening part 13a. In the first embodiment, the light source side optical path is an optical path of light that passes through the opening 13 a of the perforated mirror 13 and is formed by the irradiation optical system 10. On the other hand, the light receiving side optical path is an optical path of light reflected by the mirror portion 13 b of the perforated mirror 13 and is formed by the light receiving optical system 20. The perforated mirror 13 is disposed at a position where the opening 13a is conjugated with the pupil position of the eye E to be examined. Of the light from the fundus Er, the light that has passed through the peripheral part of the pupil (that is, the intra-pupil region close to the outer periphery of the pupil) is reflected by the mirror part 13b of the perforated mirror 13 and is received by the light receiving element 25. Guided to the side optical path. On the other hand, light from the fundus Er passing through the center of the pupil (that is, fundus reflected light passing near the principal ray of the laser light projected onto the eye E) passes through the opening 13a of the perforated mirror 13. To do.

  As shown in FIG. 2, the light reflected by the perforated mirror 13 is collected by the lens 21. When diopter correction is properly performed by the lens 14, the light passing through the lens 21 passes through the light blocking member 22 and focuses on the pinhole 23 a (that is, opening) of the pinhole plate 23. That is, in this case, the pinhole 23a is arranged at the fundus conjugate position. The light that has passed through the pinhole 23 a is received by the light receiving element 25 through the lens 24. In the first embodiment, an APD (avalanche photodiode) having sensitivity in the infrared region is used as the light receiving element 25. Each time scanning of the laser beam for one frame is performed by the scanning unit 16, a light reception signal for one frame output from the light receiving element 25 is processed by an image processing unit (not shown). Are generated.

  The light shielding member 22 is provided at a position deviating from the fundus conjugate position in the optical path between the perforated mirror 13 and the light receiving element 25. The light shielding member 22 allows light from the fundus conjugate surface to pass through and shields at least part of the reflected light from the lens surface of the objective lens system 17. In the first embodiment, the light shielding member 22 shields the vicinity of the optical axis L2 of the light receiving optical system 20. In the first embodiment, the light blocking member 22 is a black dot plate having a black dot 22a (light blocking portion of the first embodiment) that forms a light blocking region and a light transmitting plate 22b in which a ring-shaped opening is formed ( (See FIG. 4). The black spot 22a is disposed on the optical axis L2, for example, and is provided to shield light in the vicinity of the optical axis L2. The translucent plate 22b is formed in a region away from the optical axis L2, and is provided to transmit light from the fundus conjugate surface. Here, the vicinity of the optical axis L2 may be a region close to the optical axis L2 with respect to the outer edge of the light passing region from the fundus that is reflected by the perforated mirror 13. As will be described later, it is more preferable that the black dot 22a is formed in a region near the optical axis L2 with respect to the inner edge of the passage region. A suitable installation range of the black spot 22a will be described later.

  It should be noted that the installation position of the light shielding member 22 (that is, the position deviated from the fundus conjugate position) can be defined on the condition that it is at least deviated from the substantially conjugate position of the fundus. That is, the light shielding member 22 shields light in the vicinity of the optical axis L2 (mainly including light from the lens surface) out of light traveling toward the light receiving element 25, and light (mainly in a region away from the optical axis L2). Light from the fundus conjugate plane). In this case, the light shielding member 22 is configured to pass light from substantially the conjugate plane (front and rear surfaces with respect to the condensing surface of the fundus).

  Further, the installation position of the light shielding member 22 may be a position between the pupil conjugate position and the fundus conjugate position and deviating from both the pupil conjugate position and the fundus conjugate position. More specifically, as shown in FIG. 3, the installation position of the light shielding member 22 may be between the perforated mirror 13 and the pinhole plate 23. More preferably, as described below, the lens surface of the objective lens system 17 (here, the light source side lens surface 17a) may be arranged at a conjugate position.

  Reflected light at the condensing position of the fundus Er (for example, the retina surface) enters the pinhole 23a. In the first embodiment, the pinhole 23a includes not only the reflected light from the condensing position, but also tissue (for example, the inside of the retina, It is assumed that a part of the scattered light scattered in the deep layer and the tissue such as the choroid is also incident. As a result, the light receiving element 25 receives the reflected light at the condensing position of the fundus Er and part of the scattered light scattered before and after the condensing position. As the diameter of the pinhole 23a is larger, the ratio of scattered light passing through the pinhole 23a is increased, and the tissue of the fundus Er existing in the region before and after the condensing position is easily imaged together with the tissue at the condensing position. In the ophthalmology field, a front image in which the inside of the fundus Er (for example, the inside of the retina, the deep layer, and the choroid) is depicted as well as the surface of the fundus Er has various uses. For example, this type of front image is used by the examiner to specify the position of the disease inside the fundus and to determine the imaging position of the tomographic image.

  The aperture 13a of the perforated mirror 13 may be used to remove (reduce) most of the noise light together with the light from the fundus Er passing through the center of the pupil. For example, the perforated mirror 13 may be used to remove reflected light from the cornea and translucent body of the eye E and reflected light from the lens surfaces of the lenses 14 and 15. Further, the perforated mirror 13 may remove part of the reflected light from the lens surface of the objective lens system 17 (for example, the lens surface 17a on the light source side).

  The light shielding member 22 may be used, for example, to shield the reflected light from the lens surface 17a that could not be removed by the perforated mirror 13. More specifically, the lens surface of the objective lens system 17 has a curved surface portion, and the irradiated portion of the laser beam is moved, so that the reflected light passes through a wide range in the common optical path (see, for example, FIG. 3). . Therefore, for example, the reflected light reflected in the region near the optical axis L3 of the lens surface 17a may go to the light receiving element 25 through the perforated mirror 13.

  The light shielding member 22 removes the reflected light from the lens surface 17a by shielding the vicinity of the optical axis of the light receiving optical system 20. The image of the laser light irradiation area A on the lens surface 17 a is formed in the area B near the optical axis of the light receiving optical system 20 at the position of the light shielding member 22. Here, the irradiation area A is sequentially displaced by scanning with laser light. However, the displacement of the reflected light from the lens surface 17 a is canceled by passing through the scanning unit 16. As a result, the image of the irradiation area A is formed in a certain area (specifically, in the vicinity of the optical axis L2) at the installation position of the light shielding member 22 conjugate with the lens surface 17a. That is, when the reflected light from the lens surface 17a is reflected by the perforated mirror 13, the reflected light is incident on the inside of the region B by a conjugate relationship. Therefore, the light-shielding area formed by the black dots 22b is formed in the area B, so that the reflected light from the lens surface 17a is removed.

  Further, even if there is a slight error between the installation position of the light shielding member 22 and the conjugate position of the lens surface 17a of the objective lens system 17, it is possible to favorably suppress the reflected light from the lens surface 17a by the light shielding member 22. This inventor confirmed by simulation calculation using the ray tracing method. Therefore, the installation position of the light shielding member 22 may be arranged away from the front and rear with respect to the conjugate position of the lens surface 17a within a range suitable for the purpose of the present disclosure.

  When the diopter of the irradiation optical system 10 and the light receiving optical system 20 is adjusted, the conjugate position of the lens surface 17a on the optical axis L3 is displaced according to the position of the lens 14. At this time, an error may occur between the installation position of the light shielding member 22 and the conjugate position of the lens surface 17a of the objective lens system 17, but according to the simulation calculation as described above, in this case as well, the lens is formed by the light shielding member 22. The reflected light from the surface 17a can be suppressed satisfactorily. Thus, the installation position of the light shielding member 22 can be appropriately set within a range in which the reflected light from the lens surface 17a can be satisfactorily suppressed. For example, when the lens 14 is arranged at a position where the reflection from the lens surface 17a is strong (that is, the diopter is such that the fundus oculi Ef of the eye E to be examined and the pinhole 23a have a conjugate relationship). When corrected, the light shielding member 22 may be installed at a position where the lens surface 17a and the light shielding member 22 are in a conjugate relationship. Further, for example, when the fundus oculi Ef of the normal eye and the pinhole 23a are conjugate, the installation position may be such that the lens surface 17a of the objective lens system 17 and the light shielding member 22 are in a conjugate relationship.

  Below, an example in the case of setting the specific position and size of the region B is shown. Since the irradiation area A is formed in the cross section of the laser beam on the lens surface, the more specific position and size of the area B is the diameter of the opening 13a formed in the perforated mirror 13 (or the light beam branching member). Can be determined on the basis of the beam diameter of the laser light when passing through. For example, when the laser light passing through the perforated mirror 13 has a beam diameter that fills the inside of the opening 13a, the range surrounded by the light flux reflected by the perforated mirror 13 of light from the fundus Er (line in FIG. 2). The range between the s1 and the line s2) is the size of the region B. In this case, the viewing angle of the region B with respect to the pinhole 23a (that is, the apparent size when viewed from the pinhole 23a) is equal to the viewing angle of the opening 13a of the perforated mirror 13. Therefore, it is preferable that the range in which the viewing angle with respect to the pinhole 23 a as the reference is equal to the viewing angle of the opening 13 a of the perforated mirror 13 is shielded at the installation position of the light shielding member 22. Therefore, the light shielding member 22 may be formed with a light shielding region (that is, a black dot 22a) corresponding to the viewing angle of the opening 13a of the perforated mirror 13 with respect to the pinhole 23a.

  For example, the light shielding area may be such that the viewing angle with respect to the pinhole 23a is completely coincident with the opening 13a at the position where the light shielding member 22 is installed. In this case, since the light shielding member 22 does not block the light from the fundus oculi Er, the reflected light from the lens surface 17a is not transmitted to the light receiving element 25 without reducing the amount of light from the fundus Er received by the light receiving element 25. Incident light is suppressed.

  As described above, most of the light reflected by the perforated mirror 13 among the light reflected by the lens surface 17 a is shielded by the black dots 22 a of the light shielding member 22. On the other hand, the light from the fundus conjugate plane passes through the light transmitting portion 22b and travels toward the pinhole plate 23. The pinhole plate 23 transmits light scattered in the vicinity of the condensing position in addition to light from the condensing position of the fundus and blocks other light.

  As a result, a fundus image including a lot of information (for example, choroid and deep retina) in the depth direction is acquired. In the obtained fundus image, the noise light from the lens surface is reduced, so that the examiner can perform effective diagnosis and examination.

Second Embodiment
Next, the scanning laser ophthalmoscope 100 according to the second embodiment will be described with reference to FIGS. 5 to 7 focusing on differences from the first embodiment. In the description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, in the description of the second embodiment, the scanning laser ophthalmoscope 100 can capture a fundus image based on the fluorescence emitted from the fundus fluorescent material, as well as capturing the fundus image based on the fundus reflection light. For example, the scanning laser ophthalmoscope 100 may simultaneously perform imaging based on fundus reflected light and imaging based on fluorescence.

  The laser beam emitting unit 11 in the example of FIG. 5 emits light of a plurality of colors simultaneously or selectively. For example, the laser beam emitting unit 11 emits light of a total of four colors including three colors in the visible range of blue, green, and red and one color in the infrared range. Three colors in the visible range of blue, green, and red are used for color photography, for example. For example, color photography is performed by emitting three colors of blue, green, and red from the light source 11 substantially simultaneously. In addition, any one of the three colors in the visible range may be used for visible fluorescent photographing. For example, blue light may be used for FAG imaging (fluorescein fluorescence contrast imaging), which is a type of visible fluorescence imaging. In addition, for example, infrared light may be used for infrared fluorescent photographing as well as infrared photographing using infrared fundus reflected light. For example, ICG imaging (indocyanine green fluorescence imaging) is known as infrared fluorescence imaging. In this case, the infrared light emitted from the laser light source 11 is preferably set in a wavelength range different from the fluorescence wavelength of indocyanine green used in ICG imaging.

  In the example of FIG. 5, the half mirror 103 (beam splitter) and the light shielding member 210 are provided instead of the perforated mirror 13 shown in FIG. 1. The half mirror 103 is used as an optical path branching member for branching the optical paths of the light projecting optical system 10 and the light receiving optical system 20. For example, the half mirror 103 has a characteristic of transmitting a part of incident light and transmitting the remaining light. The light emitted from the laser light emitting unit 11 is guided through the half mirror 103 to the optical path on the eye E side. In addition, light that travels in the reverse direction of the light path of the light projecting optical system 10 (for example, fundus reflected light, fluorescence from the fundus, corneal reflected light, reflected light from the lens surface of the objective lens system) is reflected by the half mirror 103. Thus, the light is guided to the pinhole plate 23 side (in other words, the light receiving elements 231, 232, 233) side. In order to efficiently guide light from the eye E to the light receiving element, it is preferable that the half mirror 103 has a high reflectance with respect to the transmittance.

In the example of FIG. 5, the light blocking member 210 may be disposed in the optical path between the half mirror 103 and the pinhole plate 23. The light blocking member 210 may mainly remove corneal reflected light by being disposed on the above-described optical path. In this case, the light shielding member 210 is preferably disposed at a position conjugate with the anterior eye portion of the eye E to be examined. The details of the light shielding member 210 will be described later.
Further, in the light receiving optical system 20 of FIG. 1, only one light receiving element is provided in the light receiving optical system 20, but in the light receiving optical system 20 of FIG. 5, three light receiving elements 231, 232, and 233 are provided. It has been. The wavelength ranges in which the respective light receiving elements 231, 232 and 233 have sensitivity may be different from each other. In addition, at least two of the light receiving elements 231, 232, and 233 may have sensitivity in a common wavelength region. Each of the light receiving elements 231, 232, and 233 outputs a signal corresponding to the intensity of the received light (hereinafter referred to as a light receiving signal). In the present embodiment, the light reception signal is processed separately for each light receiving element to generate an image. That is, in this embodiment, a maximum of three types of fundus images are generated in parallel.
5 includes a light separation unit (light separation unit) 235 that separates light extracted from the fundus Er. The light separation unit 235 performs light separation in a wavelength selective manner.

  The light separation unit 235 of the present embodiment branches the optical path of the light receiving optical system 20 into three. The light separation unit 235 separates the wavelength of light extracted from the fundus Er. Although details will be described later, in this embodiment, the optical path is branched by two dichroic mirrors (dichroic filters) 235a and 235b. Note that one of the light receiving elements 231, 232, and 233 is disposed at the tip of each branch optical path.

  The light separation unit 235 separates the wavelength of the light extracted from the fundus Er and causes the three light receiving elements 231, 232, and 233 to receive light in different wavelength ranges. That is, the light receiving element 231, the light receiving element 232, and the light receiving element 233 respectively receive light in the first wavelength band, light in the second wavelength band, and light in the third wavelength band. The light in the first wavelength range, the light in the second wavelength range, and the light in the third wavelength range include, for example, fundus reflected light in the blue wavelength range, fundus reflected light in the green wavelength range, and red Any of the fundus reflection light in the wavelength region may be assigned separately. Alternatively, as light in the first wavelength range, light in the second wavelength range, and light in the third wavelength range, for example, fundus reflected light in the infrared wavelength range, fluorescence in the first wavelength range, second light May be assigned separately. Here, the light separation unit 235 causes the light receiving elements 231, 232, and 233 to receive light of three colors of blue, green, and red one by one. In addition, the fluorescence extracted from the fundus in fluorescence imaging and the fundus reflected light in the infrared region used for infrared imaging are guided to separate light receiving elements. In this case, the light separation unit 235 according to the present embodiment guides fluorescence extracted from the fundus by infrared fluorescence imaging and fluorescence extracted from the fundus by visible fluorescence imaging to different light receiving elements. Furthermore, the light separation unit 235 of the present embodiment guides light in a wavelength range that is excitation light in fluorescence imaging and fluorescence based on the excitation light to different light receiving elements. In the present embodiment, the light separation unit 235 includes dichroic mirrors 235a and 235b. By these dichroic mirrors 235a and 235b, rough wavelength separation is performed.

  In the following description, as an example, the dichroic mirrors 235a and 235b are assumed to have the following light separation characteristics (see FIG. 6). However, it is not necessarily limited to this. The dichroic mirror 235b reflects at least the light in the red wavelength region and the light in the infrared region (first infrared region), and transmits the light in the other wavelength regions. As a result, the light receiving element 231 receives light in the red wavelength region and light in the infrared region (first infrared region). The red wavelength range is used for color photography, for example. The first infrared region is used for ICG imaging, for example. That is, in the present embodiment, the first infrared region is set so that an infrared component that is the fluorescence wavelength of indocyanine green is included.

  The dichroic mirror 235a reflects at least light in the green wavelength region. As a result, the light receiving element 232 receives light in the green wavelength region. The green wavelength range is used for color photography. In this embodiment, it is used for FAG photography. That is, in the present embodiment, the green wavelength region reflected by the dichroic mirror 235b is set so that the green component that is the fluorescence wavelength of fluorescein is included.

  Light in the wavelength range that passes through the two dichroic mirrors 235a and 235b is guided to the optical path on the light receiving element 233 side. In the present embodiment, at least blue wavelength light and infrared light are transmitted. In addition, the infrared light which permeate | transmits each dichroic mirror 235a, 235b has a wavelength range of a short wavelength side with respect to the infrared light reflected by the dichroic mirror 235a. As a result, the light receiving element 233 receives light in the blue wavelength region and light in the second infrared region on the short wavelength side compared to the first infrared region. The blue wavelength range is used for color photography, for example. The second infrared region is used for infrared imaging, for example.

  In addition, the light receiving optical system 20 illustrated in FIG. 5 further includes a light blocking member 220. The light shielding member 220 may be used for shielding reflected light from the lens surface 17a, for example, similarly to the light shielding member 22 shown in FIG. In the example of FIG. 5, the light blocking member 220 may be provided at a position conjugate with the lens surface 17 a in the optical path between the half mirror 103 and the pinhole plate 23. As described above, the light separation unit 235 according to the second embodiment separately receives light in the infrared region used for infrared imaging and fluorescence (at least two types of fluorescence) in two types of contrast imaging. Since it can be guided to the element, fluorescence imaging (for example, either FAG imaging or ICG imaging) and infrared imaging can be performed simultaneously. Further, since the light separating unit 235 can guide the visible light of three colors of blue, green, and red to different light receiving elements for each color, it is possible to easily obtain a color image from these light receiving results. it can.

  In the second embodiment, as shown in FIG. 7, each light shielding member 210, 220 includes light shielding regions 210a, 220a formed in the vicinity of the optical axis and light transmitting plates 210b, 220b formed in the periphery thereof. Have each. The light-shielding part 210a and the light-shielding part 220a may be formed with the same viewing angle with respect to the pinhole 23a (that is, the apparent size when viewed from the pinhole 23a) or different apparent sizes. It may be formed. The light shielding regions 210a and 220a may shield light in each wavelength region emitted from the laser light emitting unit 11, for example. For example, the light shielding members 210 and 220 may shield light in a total of four colors, ie, three colors in the visible region of blue, green, and red and one color in the infrared region in the light shielding regions 210a and 220a. The light shielding portions 210a and 220a having such characteristics may be formed of chromium, for example. For example, the light shielding members 210 and 220 can be formed by depositing chromium on a glass plate.

  In the example of FIG. 5, insertion / removal mechanisms 215 and 225 are provided for the respective light shielding members 210 and 220. The insertion / removal mechanisms 215 and 225 insert and remove the light shielding members 210 and 220 from the optical path of the light receiving optical system 20 based on a signal from a control unit (not shown). In the second embodiment, for example, the control unit projects the excitation light to the eye E after retracting the light shielding members 210 and 220 from the optical path between the half mirror 103 and the pinhole plate 23. Further, photographing based on fluorescence may be performed. For example, the control unit may perform imaging based on fundus reflection light in a state where the light shielding members 210 and 220 are arranged in the optical path between the half mirror 103 and the pinhole plate 23. In the case of fluorescent imaging, the wavelength range of excitation light (that is, the wavelength range of reflected light from the cornea, lens surface 17a, etc.) is different from the wavelength range of fluorescence. For this reason, the light in the wavelength region of the excitation light and the fluorescence are guided to different light receiving elements by the light separation unit 235. For this reason, when light in a predetermined wavelength range is selectively emitted as excitation light from the laser light emitting unit 11, the light shielding member 210, in the optical path between the half mirror 103 and the pinhole plate 23. Even if 220 is not disposed, the reflected light from the cornea, the lens surface 17a and the like does not affect the fluorescent image as noise light. Further, since the light shielding members 210 and 220 are not disposed in the optical path between the half mirror 103 and the pinhole plate 23, it is easy to secure the amount of fluorescent light guided to the light receiving element. As a result, a good fluorescent image can be easily obtained. Thus, in the optical path between the half mirror 103 and the pinhole plate 23, the presence / absence of the light shielding members 210 and 220 is switched, so that photographing based on fundus reflected light and fluorescent photographing are performed satisfactorily. be able to.

<Third Embodiment>
Next, a scanning laser ophthalmoscope 200 according to the third embodiment will be described with reference to FIGS. 8 to 9 focusing on differences from the second embodiment. In the description of the third embodiment, the same components as those of the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 8, the scanning laser ophthalmoscope 200 according to the third embodiment is provided with light shielding members 211 and 221. The light shielding members 211 and 222 are formed with light shielding portions 211a and 221a that shield light in a wavelength region used for reflection photography and transmit fluorescence used for fluorescence photography. In this case, the light in the wavelength region used for reflection imaging may also be used as excitation light for fluorescence. In the third embodiment, as will be described later, by arranging such light shielding members 211 and 221 in the optical path between the pinhole plate 23 and the half mirror 103, fluorescence photography and reflection photography can be performed simultaneously. And well done.

  In the light receiving optical system 20 according to the third embodiment, among the light shielding members 210, 220, 211, and 221, the light shielding members 210 and 220 are disposed in the optical path, and the light shielding members 211 and 221 are disposed in the optical path. The light-shielding members are switched by the insertion / removal mechanisms 215 and 225 to a state where they are arranged outside the optical path.

  The light shielding members 211 and 221 may be obtained by replacing the light shielding portions 210a and 220a of the light shielding members 210 and 220 with filters having predetermined spectral characteristics (for example, shown in FIG. 9). The filter having the spectral characteristics shown in FIG. 9 transmits fluorescence (fluorescence is visible light) by fluorescein and lipofuscin excited by blue light. Moreover, the fluorescence by IGC excited by infrared light is transmitted. On the other hand, the filter blocks the excitation light for these fluorescences. For example, the light shielding members 211 and 221 may be formed by coating a dielectric multilayer film on a glass plate and then removing the unnecessary coating.

  In the third embodiment, the fluorescent photographing is performed with blue light from the laser light emitting unit 11 in a state where the light shielding members 211 and 221 are disposed in the optical path between the half mirror 103 and the pinhole plate 23, or This is performed by emitting at least one of infrared light. Blue light or infrared light may be emitted from the light source 11 at the same time. In this case, the fluorescence emitted from the eye E is not shielded by the filters of the light shielding members 211 and 221, and any one of the light receiving elements 231, 232 and 233 (in the case of FIG. 6, the light receiving element 231 or the light receiving element 232). ). That is, since the fluorescence is received with a larger amount of light, a good fluorescence image is easily obtained as a result. In addition, the fundus reflected light, the reflected light from the lens surface of the objective lens system, the corneal reflected light, etc. are guided to the light receiving optical system 20 together with the fluorescence. The light blocking members 211 and 221 block light reflected from the lens surface 17a of the objective lens system, cornea reflected light, and the like, thereby receiving light receiving elements 231, 232, and 233 (light receiving elements different from those that receive fluorescence, In the case of 6, the noise of the fundus reflection light guided to the light receiving element 233) is reduced. As a result, a good reflection image can be obtained simultaneously with the fluorescence image. For example, when performing fluorescence contrast imaging, the examiner can confirm the imaging position from the reflection image. For example, it is not possible to obtain an image as a fluorescence image from when the contrast medium is injected until it reaches the fundus, but even in this case, the examiner moves the imaging position by the reflected image, It can be confirmed that the alignment state has become inappropriate. Therefore, by adjusting the imaging position or the like according to the confirmation result of the reflected image, it becomes easy to reliably perform fluorescence contrast imaging. In the case of FAG imaging, the fundus reflection light of the blue excitation light is guided to the light receiving element 233, so that the fundus image by the fundus reflection light can be obtained based on the blue light. However, this fundus image tends to be a dark image. Therefore, in the case of FAG imaging, in addition to blue light that is excitation light, infrared light may be simultaneously emitted from the laser light emitting unit 11. In this case, a fundus image of the fundus reflected light of infrared light is obtained from a light receiving element 233 different from the light receiving element 232 that receives fluorescence. Thereby, the fundus image by the reflected light can be acquired well simultaneously with the fluorescence image.

  As described above, the description has been given based on the embodiment, but the present disclosure is not limited to the above-described embodiment, and various modifications can be made.

  For example, in each of the embodiments described above, the light shielding members 22, 210, and 211 are arranged at positions conjugate to the lens surface 17a closest to the light source among the lens surfaces of the objective lens system 17. However, the present invention is not limited to this. Absent. For example, the light shielding members 22, 210, and 211 may be disposed at positions that are conjugate with lens surfaces other than the lens surface 17 a, where the reflected light is a problem.

  In addition, the light shielding member 22 in the first embodiment may have a light shielding region whose viewing angle with respect to the pinhole 23a is larger than that of the opening 13a. Some reflected light may pass outside the region B due to the influence of aberration caused by the lenses 14, 15, 21, etc. through which the reflected light has passed. Since the light shielding region has a larger viewing angle than the opening 13a, light that has passed outside the region B due to aberrations of the lenses 14, 15, 21 and the like can be suitably shielded. In this case, the diameter of the light-shielding region is preferably within twice the region B. Even when the viewing angle of the light-shielding region with respect to the pinhole 23a is smaller than the viewing angle of the opening 13a, it is considered that there is a certain effect that contributes to improving the image quality of the fundus image.

  In addition, a plurality of light shielding members 22, 210, 211, 220, and 221 in each embodiment may be provided side by side in the optical axis L2 direction. For example, since the objective lens system 17 normally has a plurality of lens surfaces, the number of lens surfaces and the number of light shielding members may be made to correspond to each other. For example, when the objective lens system 17 includes four lens surfaces, four light shielding members may be arranged at the conjugate position (or the vicinity thereof) of each lens surface. Further, even if there are some errors between the light shielding members 22, 210, 211 installation position and the conjugate position of the lens surface 17a, and between the light shielding members 220, 221 and the conjugate position of the cornea, the light shielding member 22 There is an effect of suppressing noise light. As a specific example, as shown in FIG. 10, a smaller number of light shielding members (for example, three light shielding members 61 to 63) than the lens surface may be arranged on the light receiving side optical path. Of course, more light shielding members than the number of lens surfaces may be arranged. When three or more light shielding members are arranged side by side in the optical axis L2 direction of the light receiving optical system 20, the interval between the light shielding members may be made closer to the side closer to the light receiving element 25. In this case, noise light can be removed more favorably than when the light shielding members are installed at equal intervals.

  Further, when the lens 14 is moved for diopter correction, the conjugate position with each lens surface 17a on the light receiving side optical path is moved. On the other hand, by providing a plurality of light shielding members as shown in FIG. 10 as a specific example, noise light can be suppressed satisfactorily even when diopter correction is adjusted.

  In the above embodiment, the light shielding members 22, 210, 211, 220, and 221 have been described as being fixedly disposed on the optical path of the light receiving optical system 20, but at least one of the light shielding members 22, 210, 221 has been described. A mechanism for displacing 211, 220, 221 in the optical axis direction may be provided. For example, at least one of the light shielding members 22, 210, 211, 220, and 221 may be moved in conjunction with the position of the lens 14 that performs diopter correction. For example, in the case of the first embodiment, the light shielding member 22 may have a light shielding member moving mechanism that arranges the light shielding member 22 at a conjugate position with the lens surface of the objective lens system 17 according to the diopter of the eye E.

  Moreover, in the said 1st Embodiment, although the perforated mirror 13 was illustrated and demonstrated as an optical path branch member, it is not necessarily limited to this. For example, the optical path may be branched using a mirror without the opening 13a. Specifically, in the example of FIG. 1, a mirror in which the opening 13 a and the mirror 13 b are interchanged may be disposed at the position of the perforated mirror 13. In this case, the configuration of the irradiation optical system 10 from the perforated mirror 13 to the light source 11 is arranged on the reflection side of the mirror, and the configuration of the light receiving optical system 20 from the perforated mirror 13 to the light receiving element 25 is on the transmission side of the mirror. By arranging, the same effects as the above embodiment can be obtained. In this case, the peripheral portion of the mirror that guides light from the fundus to the light receiving element 25 side may be formed of a transparent material such as glass or plastic, or may be a space where no object is arranged. Good. As an example of this type of optical path branching member, refer to Japanese Unexamined Patent Application Publication No. 2010-220773.

  Moreover, the structure shown in FIG. 11 may be sufficient as an optical path branch member, for example. In FIG. 11, the optical path branching member includes a half mirror 113, an irradiation side light shielding portion 114, and a light receiving side light shielding portion 115. The half mirror 113 is disposed to be inclined with respect to the optical axis L1 between the laser beam emitting unit 11 and the diopter correcting lens 14. The half mirror 113 may be set to have a higher reflectance than the transmittance in order to reduce the exposure amount to the eye E.

  In the irradiation side light shielding portion 114, an opening centered on the optical axis L1 and a light shielding region around the opening are formed. In FIG. 11, the irradiation-side light shielding portion 114 is disposed between the half mirror 113 and the lens 12. The laser light is shaped by passing the laser light through the opening of the irradiation-side light shielding portion 114. The light-receiving side light-shielding portion 115 is used to remove corneal reflection of laser light. The light-receiving side light-shielding part 115 is disposed in the vicinity of the pupil conjugate position of the eye E between the half mirror 113 and the light receiving element 25 (more specifically, between the half mirror 113 and the lens 21). The light-receiving side light-shielding part 115 is provided with a light-shielding area (a rear part, for example, a black spot) in the vicinity of the optical axis L2. In this case, the second light-shielding part (for example, the light-shielding member 22 in the above-described embodiment) that shields the reflection from the lens surface of the objective lens system 17 is located away from a position conjugate with the pupil of the eye to be examined. Provided.

  Further, the apparatus shown in FIG. 11 may further include an insertion / removal mechanism that inserts / removes at least one of the light-projecting-side light-shielding portion 114 and the light-receiving-side light-shielding portion 115 from the optical path. For example, the diameter of the laser beam toward the eye E to be examined is increased by taking out the light projecting side light shielding portion 114 from the optical path. In this case, the light density in the anterior segment of the eye E can be reduced, which is more preferable from the viewpoint of light safety. Further, if the diameter of the laser beam is increased, the limitation due to the diffraction limit is relaxed, so that better resolution may be obtained. Further, for example, in the case of fluorescent photographing, the amount of light to the light receiving element 25 can be increased by removing the light receiving side light shielding portion 115 from the optical path.

  The light branching member may be a polarization beam splitter. In this case, a polarization beam splitter that transmits the linearly polarized light may be used together with the laser light emitting unit 11 that emits the linearly polarized light. Since reflections at the objective lens surface and the corneal surface preserve polarization, these reflections are easily removed by the polarizing beam splitter. As a result, coupled with the effects of the light shielding members 22, 220, 221 can better suppress noise on the fundus image.

  Moreover, although the said embodiment demonstrated the case where the light shielding member 22 was a plate-shaped member, it is not necessarily restricted to this, A solid-shaped member may be sufficient. For example, in the first embodiment, any member that blocks light at least in a range between the line s1 and the line s2 may be used. For example, a conical opaque member that fills a range between the line s1 and the line s2 may be used as the light shielding member.

  Moreover, in each said embodiment, the structure which can change the magnitude | size of the pinhole 23a may be sufficient as the pinhole board 23. FIG. For example, it may have a configuration in which two or more pinholes having different diameters are provided and any one of them is switched on the optical path, or a known variable aperture configuration in which the aperture diameter can be adjusted. Good.

  Moreover, although each said embodiment demonstrated the case where the pinhole board 23 was provided as a 1st light-shielding part, it is not necessarily limited to this. The first light-shielding unit is a first light-shielding unit disposed on the fundus conjugate surface, and a first opening that allows light in the vicinity of the optical axis out of light traveling from the fundus conjugate surface to the light receiving element is on the optical axis. A first light-blocking member that blocks other light traveling from the conjugate plane toward the light-receiving element, and passing light from a predetermined direction in a region away from the optical axis among light traveling from the fundus conjugate plane to the light-receiving element. A second light shielding member that shields other light traveling from the fundus conjugate surface toward the light receiving element, and an aperture that allows light from all directions to pass in a region away from the optical axis. The structure containing at least any one of the 3rd light-shielding member to have may be sufficient. For a more detailed configuration of the first to third light shielding members, refer to, for example, the ring aperture and the light shielding portion described in Japanese Patent Laid-Open No. 2009-095632.

  Further, the arrangement of the first light-shielding portion (for example, the pinhole plate 23, the ring aperture, etc.) at the fundus conjugate position includes an arrangement at a substantially conjugate position. In this case, of the light from the fundus oculi Er, light unnecessary for photographing is shielded and set in a range acceptable as a photographed image. Further, the fundus conjugate plane includes a substantially conjugate plane.

  In the above embodiment, the first light shielding part (pinhole plate 23, ring aperture, etc.) and the second light shielding part (for example, light shielding member 22) may be, for example, a diaphragm and a light shielding plate. As an example, the stop may be formed by a liquid crystal shutter.

  In the above embodiment, the scanning laser ophthalmoscope 1 is an apparatus that captures a front image of the fundus by scanning the laser beam with the fundus as an observation surface. However, the present invention is not necessarily limited to this, and the scanning laser ophthalmoscope 1 may be a device that captures a front image of a part other than the fundus. For example, the scanning laser ophthalmoscope may be a device that captures a front image of the anterior segment by scanning laser light with the anterior segment as an observation surface.

  In this case, the first light shielding part (for example, the pinhole plate 23, the ring aperture, etc.) is disposed at a position conjugate with the anterior eye part. Further, the second light shielding part (for example, the light shielding member 22 or the like) shields at least a part of the reflected light from the lens surface 17a of the objective lens system 17 and allows the light from the anterior ocular segment conjugate surface to pass therethrough. Good. Further, the second light shielding part may be arranged at a position conjugate with the lens surface 17a. Moreover, the perforated mirror etc. which were illustrated in the said embodiment may be used for an optical path branching member, and a simple half mirror may be used.

  In the above-described embodiment, the scanning laser ophthalmoscope 1 has been described as an SLO apparatus that scans laser light two-dimensionally on the observation surface. However, the present invention is not limited to this. For example, the scanning laser ophthalmoscope 1 may be a so-called line scan SLO. In this case, the line-shaped laser beam is scanned one-dimensionally on the observation surface based on the operation of the scanning unit 16.

DESCRIPTION OF SYMBOLS 1 Scanning laser ophthalmoscope 10 Irradiation optical system 11 Laser light emission part 13 Hole mirror 13a Aperture 16 Scanning part 17 Objective lens system 17a Lens surface 20 Light-receiving optical systems 22, 210, 211, 220, 221 Light shielding members 22a, 210a, 211a, 220a, 221a Light-shielding portions 22b, 210b, 220b Light-transmitting plate 23 Pinholes 25, 231, 232, 233 Light-receiving element E Eye to be examined Er Fundus L1 Optical path L2 Optical path L3 Optical path

Claims (10)

An irradiation light source, a scanning unit for scanning laser light emitted from the irradiation light source on the fundus of the eye to be examined, and an objective lens system for guiding the laser light scanned by the scanning unit to the fundus of the eye to be examined Irradiating optical system for irradiating the fundus with laser light,
A first light-shielding member disposed at a position conjugate with the fundus of the eye to be examined; the objective lens system is shared with the irradiation optical system; and the light from the fundus is emitted from the laser light irradiated by the irradiation optical system. A light receiving optical system that causes the light receiving element to receive light through the first light shielding member;
An optical path branching member for branching the optical path of the irradiation optical system and the light receiving optical system;
A scanning laser ophthalmoscope for obtaining an image of the fundus oculi based on a light reception signal from the light receiving element,
Provided at a position deviating from the fundus conjugate position of the eye to be examined in the optical path between the optical path branching member and the light receiving element, allowing light from the fundus conjugate plane to pass through, and from the lens surface of the objective lens system A second light shielding member that shields at least part of the reflected light;
A scanning laser ophthalmoscope, wherein the light receiving element receives light from the fundus that has passed through the first light shielding member and the second light shielding member.   The second light shielding member passes a light from the fundus conjugate surface and a central light shielding portion disposed on the optical axis for shielding at least a part of the reflected light from the lens surface of the objective lens system. The scanning laser ophthalmoscope according to claim 1, further comprising a ring-shaped opening.   2. The scanning type according to claim 1, wherein the central light-shielding portion is a filter having a spectral characteristic that shields light in a wavelength region of the laser light and transmits fluorescence excited on the fundus of the eye to be examined by the laser light. Laser ophthalmoscope. The laser light includes at least light in an infrared region,
The central light-shielding unit shields light in the infrared region, and uses the light in the infrared region included in the laser light or light in a wavelength region different from the light in the infrared region as excitation light. The scanning laser ophthalmoscope according to claim 1, wherein the scanning laser ophthalmoscope is a filter having a spectral characteristic that transmits fluorescence excited by.   5. The scanning laser ophthalmoscope according to claim 1, wherein the second light shielding member is disposed at a position conjugate with a lens surface of the objective lens system. 6. The optical path branching member guides the laser light from the light source to the scanning unit at the central part, removes light from the fundus that has passed through the central part of the pupil from the light receiving optical system, and at the peripheral part, the pupil The light from the fundus that has passed through the periphery of the
6. The scanning laser ophthalmoscope according to claim 1, wherein the second light shielding member has a light shielding region corresponding to an apparent size of the central portion with respect to the opening. .   The second light-shielding member has an apparent size of the light-shielding region with the opening as a reference within twice the apparent size of the central portion with the opening as a reference. Item 7. A scanning laser ophthalmoscope according to item 6. The first light shielding member is a first light shielding member disposed on a fundus conjugate surface,
A first opening that allows light in the vicinity of the optical axis to pass through the light from the fundus conjugate surface to the light receiving element is disposed on the optical axis; and a first light shielding member that blocks other light from the conjugate surface toward the light receiving element;
Of the light traveling from the fundus conjugate surface to the light receiving element, an opening that allows light from a predetermined direction in a region away from the optical axis to pass is disposed at a position off the optical axis. A second light shielding member for shielding light;
A third light shielding member having an opening through which light from all directions in a region away from the optical axis passes;
The scanning laser ophthalmoscope according to claim 1, comprising at least one of the following.   9. The scanning laser ophthalmoscope according to claim 1, further comprising an insertion / removal mechanism for retracting the second light shielding portion from the optical path of the light receiving optical system. Irradiation light source, scanning means for scanning laser light emitted from the irradiation light source on the observation surface of the eye to be examined, and objective lens system for guiding the laser light scanned by the scanning means to the observation surface And an irradiation optical system for irradiating the observation surface with laser light, and
A first light-shielding portion disposed at a position conjugate with the observation surface of the eye to be examined; and sharing the objective lens system with the irradiation optical system, and from the observation surface by the laser light irradiated by the irradiation optical system A light receiving optical system that causes the light receiving element to receive the light via the first light blocking portion, an optical path branching member for branching the optical path of the irradiation optical system and the light receiving optical system,
A scanning laser ophthalmoscope for obtaining an image of the observation surface based on a light reception signal from the light receiving element,
Provided at a position deviated from a position conjugate with the observation surface of the eye to be examined in an optical path between the optical path branching member and the light receiving element, and allows light from a surface conjugate with the observation surface to pass through, A second light-shielding portion that shields at least part of the reflected light from the lens surface;
A scanning laser ophthalmoscope characterized by causing the light receiving element to receive light from the observation surface that has passed through the first light shielding portion and the second light shielding portion.