Ophthalmic devices

Abstract

To inhibit noise from being mixed into tomographic information.SOLUTION: An ophthalmologic apparatus includes: a first light source 26 for outputting a first light; a second light source 76 for outputting a second light; a scanner 32 for executing scanning of the first light output from the first light source in a first range of an eye to be examined, and executing scanning of the second light output from the second light source in a second range different from the first range of the eye to be examined; a first objective lens 42 disposed between the scanner and the eye to be examined for irradiating the first range of the eye to be examined with the first light scanned by the scanner; and a second objective lens 54 disposed between the scanner and the eye to be examined for irradiating the second range of the eye to be examined with the second light scanned by the scanner.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an ophthalmic apparatus, and more particularly to an ophthalmic apparatus capable of acquiring tomographic information for each of different measurement ranges (for example, an anterior segment, a fundus, etc.) of a subject's eye. [Background technology]

[0002] Ophthalmic devices that acquire tomographic information for different measurement ranges of a subject's eye have been developed. For example, the ophthalmic device of Patent Document 1 can acquire a tomographic image of the anterior segment of the subject's eye and a tomographic image of the fundus of the subject's eye. This ophthalmic device includes an anterior segment light source and a fundus light source having a wavelength different from that of the anterior segment light source. Light from the anterior segment light source is irradiated onto the anterior segment of the subject's eye through an anterior segment optical path in which a scanner and an objective lens are arranged. Light from the fundus light source passes through a scanner, branches from the anterior segment optical path to a fundus optical path in which a relay lens is arranged, and merges again from the fundus optical path to the anterior segment optical path, and is irradiated onto the fundus of the subject's eye through the same objective lens. That is, a part of the fundus optical path is the same as the anterior segment optical path. In this ophthalmic device, a scanner and objective lens are shared between the anterior segment and the fundus, while an optical path for the fundus that branches off and joins the optical path for the anterior segment is provided between the scanner and the objective lens, thereby obtaining both anterior segment tomographic images and fundus tomographic images.

[0003] The ophthalmic device of Patent Document 2 is also capable of acquiring a tomographic image of the anterior segment of the subject's eye and a tomographic image of the fundus of the subject's eye. In this ophthalmic device, light from a light source for the anterior segment passes through a scanner and an objective lens for the anterior segment and is irradiated onto the anterior segment of the subject's eye. Light from a light source for the fundus passes through a scanner for the fundus, passes through a relay lens, and is irradiated onto the fundus of the subject's eye via the same objective lens. That is, the ophthalmic device of Patent Document 2 is equipped with a scanner for the anterior segment and a scanner for the fundus, but shares the objective lens, and acquires both a tomographic image of the anterior segment and a tomographic image of the fundus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 9,072,460 [Patent Document 2] Special Publication No. 2018-525036 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned conventional ophthalmic apparatus, in order to obtain tomographic information for each of the different measurement ranges of the test eye, light from multiple light sources is irradiated onto different measurement ranges of the test eye. Therefore, a configuration for obtaining tomographic information for one measurement range affects the obtaining of tomographic information for another measurement range, and a problem occurs in that noise is mixed into the obtained tomographic information. This specification provides a technology for suppressing the mixing of noise into tomographic information in an ophthalmic apparatus capable of obtaining tomographic information for each of the different measurement ranges of the test eye. [Means for solving the problem]

[0006] A first ophthalmic device disclosed in the present specification includes a first light source that outputs a first light, a second light source that outputs a second light, a first scanning optical system that scans a first range of the test eye with the first light output from the first light source, a second scanning optical system that scans a second range different from the first range of the test eye with the second light output from the second light source, a first interferometer that acquires tomographic information of the first range based on a first interference light obtained from a reflection light of the first light from the test eye, and a second interferometer that acquires tomographic information of the second range based on a second interference light obtained from a reflection light of the second light from the test eye. The central wavelength of the first light is different from the central wavelength of the second light. The first scanning optical system includes a first objective lens unit that irradiates the first range of the test eye with the first light. The second scanning optical system includes a second objective lens unit that irradiates the second range of the test eye with the second light. The first light is transmitted through the first objective lens section while not transmitting through the second objective lens section. The second light is transmitted through the second objective lens section while not transmitting through the first objective lens section.

[0007] In the above-mentioned ophthalmic device, a first objective lens unit dedicated to obtaining tomographic information of a first range is arranged, and a second objective lens unit dedicated to obtaining tomographic information of a second range is arranged, which makes it possible to suppress the inclusion of noise in the tomographic information, compared to conventional ophthalmic devices. That is, in the conventional ophthalmic device, the objective lens is shared between the anterior eye measurement and the fundus measurement, and both the light from the light source for the anterior eye and the light from the light source for the fundus are irradiated to the eye through the same objective lens. With such a configuration, the light from the light source for the fundus is irradiated to the fundus of the eye through two lenses, namely, the relay lens and the objective lens. Therefore, the lens power (refractive power) required to scan the fundus with light is distributed to the two lenses. Therefore, the principal ray of light between the relay lens and the objective lens is always nearly parallel to the optical axis regardless of the scanning angle, and is incident on the objective lens placed on the eye at an angle nearly perpendicular. As a result, a problem occurs in that noise due to light reflected on the surface of the objective lens is reflected in the tomographic image of the fundus. The above-mentioned ophthalmologic apparatus includes a first objective lens unit dedicated to acquiring tomographic information of a first range, and a second objective lens unit dedicated to acquiring tomographic information of a second range. Therefore, the lens power for irradiating light to the first range can be imparted by the first objective lens unit, and the lens power for irradiating light to the second range can be imparted by the second objective lens unit. Therefore, the angle of incidence of light to the first objective lens unit can be set relatively freely, and the angle of incidence of light to the second objective lens unit can be set relatively freely. This makes it possible to suppress noise caused by light reflected on the surface of the objective lens unit from being mixed into the tomographic information. The above-mentioned "objective lens section" may be composed of one lens (single lens) or may be composed of a combination of multiple lenses that fit in the same lens barrel. When the objective lens section is composed of a combination of multiple lenses, it is preferable to use a laminated lens such as a doublet lens or triplet lens that minimizes the number of interfaces with air.

[0008] A second ophthalmic device disclosed in the present specification includes a first light source that outputs a first light, a second light source that outputs a second light, a first scanning optical system that scans a first range of the test eye with the first light output from the first light source, a second scanning optical system that scans a second range different from the first range of the test eye with the second light output from the second light source, a first interferometer that acquires tomographic information of the first range based on a first interference light obtained from a reflected light of the first light from the test eye, and a second interferometer that acquires tomographic information of the second range based on a second interference light obtained from a reflected light of the second light from the test eye. The first range is an anterior segment of the test eye. The second range is a fundus of the test eye. The central wavelength of the first light is different from the central wavelength of the second light. The first optical path that is an optical path of the first light includes an overlapping section that overlaps with the second optical path that is an optical path of the second light, and a first non-overlapping section that does not overlap with the second optical path. The second optical path includes the overlap section and a second non-overlapping section that does not overlap with the first optical path. The ophthalmic device further includes an observation port facing the eye. The overlapping section includes a first overlapping section including a section connecting the eye to be examined and the observation port. The ophthalmic device further includes a first dichroic mirror disposed at a first position where the first overlapping section branches into the first non-overlapping section and the second non-overlapping section. The first dichroic mirror reflects the first light while transmitting the second light. An AR coating (Anti Reflection Coating) is applied to the rear surface of the first dichroic mirror for the wavelength band of the first light.

[0009] In the above ophthalmic device, the first light output from the first light source for the anterior segment is reflected by the first dichroic mirror and irradiated to the anterior segment of the subject's eye through the viewing port. This makes it possible to avoid the generation of ghost noise caused by irradiating the anterior segment with light transmitted through the dichroic mirror. That is, when irradiating the anterior segment of the subject's eye with light transmitted through the first dichroic mirror, the back-reflected light of the first dichroic mirror is also irradiated to the anterior segment of the subject's eye. Since the reflection intensity of light from the iris is strong, the back-reflected light of the first dichroic mirror is also strongly reflected from the iris, which causes ghost noise to be mixed into the tomographic information. In the above ophthalmic device, when acquiring tomographic information of the anterior segment of the subject's eye, the first light reflected by the first dichroic mirror is irradiated to the anterior segment of the subject's eye, so that it is possible to suppress the mixing of ghost noise into the tomographic information. Furthermore, in the above-mentioned ophthalmic apparatus, the rear surface of the first dichroic mirror is provided with an AR coating for the wavelength band of the first light, which reduces the intensity of the first light reflected by the rear surface of the first dichroic mirror when acquiring tomographic information of the anterior segment of the subject's eye, thereby further suppressing noise from being mixed into the tomographic information. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic configuration diagram of an optical system of the ophthalmic apparatus according to the first embodiment. [Diagram 2] FIG. 2 is a diagram for explaining an anterior eye scanning optical system of the ophthalmic apparatus according to the first embodiment. [Diagram 3] FIG. 2 is a diagram for explaining a fundus scanning optical system of the ophthalmologic apparatus according to the first embodiment. [Figure 4] 3 is a diagram for explaining the configuration of a light receiving system for receiving light reflected from a subject's eye in the total refractive power measuring optical system of the ophthalmic apparatus of the first embodiment. FIG. [Diagram 5] FIG. 2 is a diagram for explaining a front monitor optical system of the ophthalmic apparatus of the first embodiment. [Figure 6] FIG. 2 is a diagram for explaining a position detection light projection system of the ophthalmic apparatus according to the first embodiment. [Figure 7]FIG. 2 is a diagram for explaining a position detection light receiving optical system of the ophthalmic apparatus according to the first embodiment. [Figure 8] FIG. 2 is a diagram for explaining a fixation target optical system of the ophthalmic apparatus according to the first embodiment. [Figure 9] 13 is an example of a tomographic image in which reflection noise from an objective lens is captured in an ophthalmic apparatus according to the conventional technology. [Figure 10] 13 is an example of an image captured during total refractive power measurement in an ophthalmic apparatus according to the related art, in which reflection noise from an objective lens is reflected. [Figure 11] FIG. 2 is a diagram for explaining rear surface reflection of a dichroic mirror. [Figure 12] 13 is an example of an anterior segment tomographic image of a subject's eye E in which ghost noise caused by back reflection of a dichroic mirror is reflected. [Figure 13] 1 is a diagram for explaining back-surface reflection of light transmitted through a front surface of a dichroic mirror. [Figure 14] Examples of anterior segment tomographic images obtained when changing iris signal strength DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the ophthalmic device disclosed in the present specification, the first optical path, which is an optical path of the first light, may include an overlapping section that overlaps with the second optical path, which is an optical path of the second light, and a first non-overlapping section that does not overlap with the second optical path. The second optical path may include the overlapping section and a second non-overlapping section that does not overlap with the first optical path. The first objective lens unit may be disposed in the first non-overlapping section. The second objective lens unit may be disposed in the second non-overlapping section. With this configuration, the first light can be irradiated to the subject's eye via the first objective lens unit, and the second light can be irradiated to the subject's eye via the second objective lens unit.

[0012] In the ophthalmic device disclosed in the present specification, the first scanning optical system may include a first scanner that scans a first light output from a first light source. The second scanning optical system may include a second scanner that scans a second light output from a second light source. The first scanner may be disposed in a first non-overlapping section, and the second scanner may be disposed in a second non-overlapping section. With this configuration, the first scanner can be suitable for scanning a first range with light, and the second scanner can be suitable for scanning a second range with light.

[0013] The ophthalmic device disclosed in the present specification may further include a scanner that scans the first light output from the first light source and the second light output from the second light source. The scanner may be disposed in an overlapping section and shared by the first scanning optical system and the second scanning optical system. The first objective lens unit may be disposed between the scanner and the subject's eye. The second objective lens unit may be disposed between the scanner and the subject's eye. With this configuration, the scanner is shared by the first scanning optical system and the second scanning optical system, so that the number of components of the optical system can be reduced. Furthermore, by sharing the scanner, the device can be made smaller.

[0014] In the ophthalmic device disclosed in the present specification, the first range may be the anterior segment of the subject's eye. The second range may be the fundus of the subject's eye. The ophthalmic device may further include an observation port facing the subject's eye. The overlapping section may include a first overlapping section including a section connecting the subject's eye and the observation port. The ophthalmic device may further include a first dichroic mirror disposed at a first position where the first overlapping section branches into a first non-overlapping section and a second non-overlapping section. The first dichroic mirror may reflect the first light while transmitting the second light. According to this configuration, when acquiring tomographic information of the anterior segment of the subject's eye, the first light reflected by the first dichroic mirror is irradiated onto the anterior segment of the subject's eye. This makes it possible to avoid the generation of ghost noise caused by irradiating the anterior segment with light transmitted through the dichroic mirror.

[0015] In the ophthalmic apparatus disclosed in the present specification, the rear surface of the first dichroic mirror may be coated with an AR (Anti Reflection Coating) coating for the wavelength band of the first light. With this configuration, when acquiring tomographic information of the anterior segment of the subject's eye, the intensity of the first light reflected by the rear surface of the first dichroic mirror is suppressed, and it is possible to further suppress noise from being mixed into the tomographic information.

[0016] In the ophthalmic device disclosed in the present specification, the overlapping section may include a second overlapping section including a section connecting the scanner and a second position where the first non-overlapping section and the second non-overlapping section merge / diverge. The ophthalmic device may further include a second dichroic mirror disposed at the second position. The second dichroic mirror may reflect the first light while transmitting the second light. According to this configuration, when acquiring tomographic information of the anterior segment of the subject's eye, the first light reflected by the second dichroic mirror is irradiated onto the anterior segment of the subject's eye. This makes it possible to avoid the occurrence of ghost noise caused by irradiating the anterior segment with light transmitted through the dichroic mirror.

[0017] In the ophthalmic apparatus disclosed in the present specification, the back surface of the second dichroic mirror may be coated with an AR (Anti Reflection Coating) coating for the wavelength band of the first light. With this configuration, when acquiring tomographic information of the anterior segment of the subject's eye, the intensity of the first light reflected by the back surface of the second dichroic mirror can be suppressed, and noise can be prevented from being mixed into the tomographic information.

[0018] In the ophthalmic device disclosed in the present specification, a third dichroic mirror may be further disposed at a third position, which is different from the second position, among the positions at both ends of the second overlapping section. The third dichroic mirror may reflect the first light while transmitting the second light. In addition, an AR coating (Anti Reflection Coating) may be applied to the rear surface of the third dichroic mirror for the wavelength band of the first light. With this configuration, when acquiring tomographic information of the anterior segment of the subject's eye, the intensity of the reflected light of the first light reflected by the rear surface of the third dichroic mirror can be suppressed, and noise can be prevented from being mixed into the tomographic information. EXAMPLES

[0019] The ophthalmic device according to the present embodiment will be described below. The ophthalmic device according to the present embodiment can obtain a tomographic image of the anterior part of the eye E, obtain a tomographic image of the fundus of the eye E, and measure the total refractive power of the eye E. Therefore, information for comprehensively diagnosing the condition of the eye E can be obtained by one ophthalmic device. In order to perform the above-mentioned functions, the ophthalmic device according to the present embodiment includes an optical system 10 shown in FIG. 1. That is, the optical system 10 includes an anterior part scanning optical system, a fundus scanning optical system, a total refractive power measuring optical system, a front monitor optical system, a position detection light projecting optical system, a position detection light receiving optical system, and a fixation target optical system. Each optical system will be described below.

[0020] As shown in Figure 2, the anterior eye scanning optical system is composed of an anterior eye light source 26 (an example of a first light source), a collimator lens 28, a dichroic mirror 30, a two-dimensional scanner 32, a dichroic mirror 34, a total reflection mirror 40, an objective lens 42 (an example of a first objective lens unit), and a dichroic mirror 44.

[0021] The anterior eye light source 26 is a wavelength sweep type light source, and the wavelength (wave number) of the output light changes at a predetermined period. The anterior eye light source 26 outputs light with a long wavelength, and can output light with a central wavelength of, for example, 0.95 μm or more and 1.80 μm or less. In this embodiment, the anterior eye light source 26 outputs light with a central wavelength of 1.31 μm. When long wavelength light is used, it becomes easier to pass through, for example, opacity of the crystalline lens, ciliary body, conjunctiva, sclera, and other strongly scattering tissues, and further, since the light is absorbed by water and does not easily reach the fundus, it is possible to irradiate strong light. Therefore, by outputting light with a central wavelength of 0.95 μm or more from the anterior eye light source 26, it is possible to increase the degree of reach to tissues made of scattering materials. In addition, light with a central wavelength of 0.95 μm or more and 1.80 μm or less is less dispersed by water, so when light in this range is irradiated to the subject's eye E, an anterior eye OCT image with good image quality can be obtained. Furthermore, by outputting light having a central wavelength of 1.80 μm or less from the anterior-segment light source 12, the target site can be measured with good sensitivity using an indium-gallium-arsenide (InGaAs) light receiving element. In this embodiment, by outputting light having a wavelength of 0.95 μm or more and 1.80 μm or less from the anterior-segment light source 26, a tomographic image of the anterior segment of the subject's eye E can be suitably captured.

[0022] The light output from the anterior eye light source 26 (an example of the first light) is emitted from an optical fiber (not shown) via the interferometer 25 and enters the collimator lens 28. The collimator lens 28 converts the light output from the anterior eye light source 26 into parallel light. The parallel light from the collimator lens 28 is reflected by the dichroic mirror 30 and enters the two-dimensional scanner 32. The two-dimensional scanner 32 scans the incident light in two directions, the x direction and the y direction, on the anterior eye of the subject's eye E. In this embodiment, a galvano scanner is used for the two-dimensional scanner 32. Note that the two-dimensional scanner 32 may be anything other than a galvano scanner, and may be, for example, a MEMS mirror capable of biaxial scanning. The light emitted from the two-dimensional scanner 32 enters the objective lens 42 via the dichroic mirror 34 and the total reflection mirror 40. The light incident on the objective lens 42 passes through the objective lens 42, is reflected by the dichroic mirror 44, is collected near the anterior segment of the subject's eye E, and is irradiated onto the subject's eye E. In this embodiment, the two-dimensional scanner 32 is disposed at the rear focal point of the objective lens 42. Therefore, the light emitted from the two-dimensional scanner 32 reaches the subject's eye E parallel to the optical axis (optical path L12). That is, in this embodiment, the light is scanned by telecentric scanning onto the anterior segment of the subject's eye E. Note that an observation port 45 is disposed between the dichroic mirror 44 and the subject's eye E. The observation port 45 is disposed at a position facing the subject's eye E during measurement. The observation port 45 is provided in a housing (not shown), and the optical system 10 is accommodated in this housing.

[0023] The light reflected by the anterior segment of the subject's eye E travels along the same path as the above-mentioned path, and is guided to an interferometer 25 (an example of a first interferometer) via an optical fiber (not shown). The interferometer 25 combines the light reflected by the anterior segment of the subject's eye E with a reference light separately generated from the light output from the anterior segment light source 26, detects the interference light obtained by combining, and outputs an interference signal. In the ophthalmic apparatus of this embodiment, a tomographic image of the anterior segment of the subject's eye E is obtained by processing the interference signal output from the interferometer 25.

[0024] As is clear from the above explanation, in the anterior eye scanning optical system, the paths along which light passes are optical path L3, a portion of optical path L4 (more specifically, the range between the dichroic mirror 30 and the two-dimensional scanner 32), optical path L5, optical path L6, optical path L8 (i.e., the range between the total reflection mirror 40 and the dichroic mirror 44), and optical path L12.

[0025] As shown in Figure 3, the fundus scanning optical system is composed of a fundus light source 76 (an example of a second light source), a lens 22, a polarizing beam splitter 24, a dichroic mirror 30, a two-dimensional scanner 32, a dichroic mirror 34, a dichroic mirror 56, an objective lens 54 (an example of a second objective lens unit), and a dichroic mirror 44.

[0026] The fundus light source 76 is a fixed wavelength type light source. The fundus light source 76 outputs light having a different central wavelength from the light output from the anterior eye light source 26, and can output light having a central wavelength of 0.40 μm or more and 1.15 μm or less, for example. Also, for example, the fundus light source 76 may output light having a half-width in a wavelength range different from the half-width wavelength range of the light output from the anterior eye light source 12. In this embodiment, the fundus light source 76 outputs light having a central wavelength of 0.83 μm. Light having a central wavelength of 0.40 μm or more and 1.15 μm or less has a high transmittance in the eyeball. Therefore, by outputting light having a central wavelength of 0.40 μm or more and 1.15 μm or less from the light source, the light can be sufficiently irradiated to the fundus of the subject eye E. In addition, light having a central wavelength of 0.40 μm or more and 0.95 μm or less has a high sensitivity of a silicon-based light receiving element. Furthermore, light with a central wavelength of 0.95 μm or more and 1.15 μm or less has little wavelength dispersion due to water, so a fundus OCT image with good quality can be obtained by irradiating light in this range onto the subject's eye E. Therefore, by outputting light with a central wavelength of 0.40 μm or more and 1.15 μm or less from the light source, a tomographic image of the fundus of the subject's eye E can be suitably captured.

[0027] The light output from the fundus light source 76 (an example of the second light) is adjusted to be light containing only P-polarized components, and then emitted from an optical fiber (not shown) via an interferometer 77. The light emitted from the optical fiber passes through the lens 22, the polarizing beam splitter 24, and the dichroic mirror 30, and enters the two-dimensional scanner 32. The two-dimensional scanner 32 scans the incident light in two directions, the x direction and the y direction, on the fundus of the subject's eye E. The light emitted from the two-dimensional scanner 32 passes through the dichroic mirror 34, is reflected by the dichroic mirror 56, and enters the objective lens 54. The light that enters the objective lens 54 passes through the objective lens 54 and the dichroic mirror 44, is collected near the fundus of the subject's eye E, and is irradiated onto the fundus of the subject's eye E. In the ophthalmic apparatus of this embodiment, the power of the objective lens 54 is set so that the fundus of the subject's eye E is irradiated with convergent light. In addition, the position of the output end of the optical fiber from which the light output from the fundus light source 76 is emitted can be moved in the direction of the optical axis (the direction in which the optical path L4 extends) (i.e., the optical path length is adjustable), and can be moved according to the refractive power of the test eye E.

[0028] The light reflected at the fundus of the subject's eye E travels along the same path as the above-mentioned path, and is guided to an interferometer 77 (an example of a second interferometer) via an optical fiber (not shown). The interferometer 77 combines the light reflected at the fundus of the subject's eye E with a reference light separately generated from the light output from the fundus light source 76, detects the interference light obtained by the combination, and outputs an interference signal. In the ophthalmic apparatus of this embodiment, a tomographic image of the fundus of the subject's eye E is obtained by processing the interference signal output from the interferometer 77.

[0029] As is clear from the above description, in the fundus scanning optical system, the optical paths L4, L5, L9, L10, and L12 are paths through which light passes. Therefore, in the anterior eye scanning optical system and the fundus scanning optical system, a part of the optical path L4 (specifically, the range between the dichroic mirror 30 and the two-dimensional scanner 32), the optical path L5, and the optical path L12 are paths that overlap (an example of an overlapping section), the optical paths L8, L6, and L3 are paths for only the light of the anterior eye scanning optical system (an example of a first non-overlapping section), and the other part of the optical path L4, the optical path L9, and the optical path L10 are paths for only the light of the fundus scanning optical system (an example of a second non-overlapping section).

[0030] Next, the total refractive power measurement optical system will be described. The light projection system that projects light onto the subject's eye E of the total refractive power measurement optical system has the same configuration as the light projection system of the fundus scanning optical system. Therefore, the light receiving system of the total refractive power measurement optical system will be described. As shown in FIG. 4, the total refractive power measurement optical system is composed of a dichroic mirror 44, an objective lens 54, a dichroic mirror 56, a dichroic mirror 34, a two-dimensional scanner 32, a dichroic mirror 30, a polarizing beam splitter 24, a lens 20, a mirror 18, an aperture 17, a lens 16, a donut lens 14, and a two-dimensional sensor 12.

[0031] As is clear from a comparison between FIGS. 3 and 4, the path of the light scattered at the fundus of the subject's eye E from the dichroic mirror 44 to the polarizing beam splitter 24 is the same as that of the fundus scanning optical system. In the polarizing beam splitter 24, only the S-polarized component of the light scattered at the fundus of the subject's eye E is reflected and irradiated onto the mirror 18 via the lens 20. The light irradiated onto the mirror 18 passes through the aperture 17, the lens 16, and the doughnut lens 14, and forms a ring-shaped image on the detection surface of the two-dimensional sensor 12. The total refractive power of the subject's eye E is calculated based on the ring image formed by the two-dimensional sensor 12. In this embodiment, the doughnut lens 14 is used to form a ring-shaped image on the light receiving surface of the two-dimensional sensor 12, but the present invention is not limited to this example. For example, a lens array may be used instead of the doughnut lens 14 to form a dot pattern on the light receiving surface of the two-dimensional sensor 12. The aperture 17, lens 16, doughnut lens 14, and two-dimensional sensor 12 are integrated and are movable in the direction of the optical axis (optical path L1), and are adapted to move according to the total refractive power of the subject's eye E.

[0032] As shown in FIG. 5, the front monitor optical system is made up of LEDs 46 and 48, a dichroic mirror 44, an objective lens 42, a total reflection mirror 40, a dichroic mirror 34, an aperture 70, a lens 72, and a two-dimensional sensor 74.

[0033] The LEDs 46 and 48 are disposed diagonally in front of the subject's eye E and illuminate the anterior segment of the subject's eye E. The LEDs 46 and 48 irradiate the subject's eye E with light having a central wavelength of 0.76 μm. The light reflected by the subject's eye E is reflected by the dichroic mirror 44, passes through the objective lens 42, is reflected by the total reflection mirror 40, passes through the dichroic mirror 34, the aperture 70, and the lens 72, and a front image of the anterior segment is formed on the two-dimensional sensor 74. The anterior segment image of the subject's eye E captured by the two-dimensional sensor 74 is displayed on a display device (not shown). The aperture 70 is disposed at the rear focal point of the objective lens 42 so that the image magnification does not change even if the anterior segment image is defocused.

[0034] 6, the position detection light projection optical system is composed of an LED 68, a lens 66, a dichroic mirror 58, a dichroic mirror 56, an objective lens 54, and a dichroic mirror 44. The LED 68 emits light with a central wavelength of 0.94 μm. The light emitted from the LED 68 passes through the lens 66, the dichroic mirrors 58 and 56, the objective lens 54, and the dichroic mirror 44, and irradiates the cornea of ​​the subject's eye E. The light irradiated to the subject's eye E is specularly reflected by the corneal surface of the subject's eye E, and a virtual image of the light emitting surface of the LED 68 is formed on an extension of the corneal apex.

[0035] The position detection light receiving optical system detects the corneal apex position in the direction (horizontal direction) perpendicular to the optical axis (optical path L12) and detects the corneal apex position in the optical axis direction (depth direction). The position detection light receiving optical system is composed of a lens 50, a two-dimensional sensor 52, and a lens 38 and a two-dimensional sensor 36 (see FIG. 7). The lens 50 and the one-dimensional sensor 52 are disposed diagonally in front of the subject's eye E. The lens 38 and the two-dimensional sensor 36 are also disposed diagonally in front of the subject's eye E. The lens 38 and the two-dimensional sensor 36, and the lens 50 and the one-dimensional sensor 52 are disposed symmetrically with respect to the optical axis (optical path L12). The light reflected at a position slightly shifted from the corneal apex of the subject's eye E is reflected in an oblique direction, passes through the lens 50, and a virtual image of the light emitting surface of the LED 68 is projected onto the two-dimensional sensor 52. Similarly, light reflected at a position slightly shifted from the corneal apex of the subject's eye E passes through the lens 38, and a virtual image of the light-emitting surface of the LED 68 is projected onto the two-dimensional sensor 36. In the ophthalmic device of this embodiment, based on the virtual image of the light-emitting surface of the LED 68 detected by the two-dimensional sensors 36 and 52, the corneal apex position in the direction (lateral direction) perpendicular to the optical axis (optical path L12) is detected, and the corneal apex position in the optical axis direction (depth direction) is also detected.

[0036] When the position of the corneal apex of the subject's eye E is detected based on the detection results of the two-dimensional sensor 36 and the two-dimensional sensor 52, the housing that houses the optical system 10 is driven by a drive device (not shown) to position the housing at a measurement position relative to the corneal apex of the subject's eye E. This positions the sight hole 45 relative to the subject's eye E, and positions the objective lenses 42, 54 of the optical system 10. Once the sight hole 45 (the objective lenses 42, 54, etc. of the optical system 10) is positioned relative to the subject's eye E, the positions of the sight hole 45 and the objective lenses 42, 54, etc. do not change relative to the subject's eye E while an anterior segment tomographic image, a fundus tomographic image, and the total refractive power of the subject's eye E are acquired.

[0037] As shown in FIG. 8, the fixation target optical system is composed of an LED 64, a lens 62, a mirror 60, dichroic mirrors 58 and 56, an objective lens 54, and a dichroic mirror 44. The LED 64 emits white light. The light from the LED 64 passes through an image film on which a symbol for the subject to fixate is printed, and is reflected by the mirror 60. The light reflected by the mirror 60 is reflected by the dichroic mirror 58, passes through the dichroic mirror 56, the objective lens 54, and the dichroic mirror 44, and is irradiated toward the subject's eye E. The LED 64 and the image film are movable in the optical axis direction (direction along the optical path L20), and their positions are adjusted according to the total refractive power of the subject's eye E.

[0038] As is clear from the above description, in the ophthalmologic apparatus of this embodiment, no objective lens is arranged in the optical path L12 between the subject's eye E and the dichroic mirror 44, the objective lens 42 dedicated to the anterior eye scanning optical system is arranged in the optical path L8 dedicated to the anterior eye scanning optical system, and the objective lens 54 dedicated to the fundus scanning optical system is arranged in the optical path L10 dedicated to the fundus scanning optical system. Therefore, compared to the conventional technology, it is possible to suppress noise caused by reflected light reflected on the surfaces of the objective lenses 42 and 54 from being mixed into the tomographic image.

[0039] That is, if a common objective lens is arranged in the optical path L12 between the subject's eye E and the dichroic mirror 44 and a relay lens is arranged in an optical path dedicated to the fundus scanning optical system as in the conventional technology, two lenses, an objective lens and a relay lens, are arranged in the fundus scanning optical system. That is, the lens power (refractive power) required to scan the fundus with light is distributed to two lenses, an objective lens and a relay lens. For this reason, the principal ray of light between the relay lens and the objective lens is always nearly parallel to the optical axis regardless of the scanning angle, and is incident on the objective lens arranged on the subject's eye side at an angle nearly perpendicular. As a result, a problem occurs in that noise due to light reflected on the surface of the objective lens (i.e., the surface opposite to the subject's eye) is reflected in the fundus tomographic image (see FIG. 9). However, in the fundus scanning optical system of the ophthalmic apparatus of this embodiment, a dedicated objective lens 54 is arranged in the optical path L10, and no lens is arranged between the objective lens 54 and the eye E, and no lens is arranged between the two-dimensional scanner 32 and the objective lens 54. Therefore, the lens power (refractive power) required for scanning the fundus with light can be imparted by the objective lens 54. As a result, the angle of incidence of light to the objective lens 54 can be adjusted, and it is possible to suppress the light reflected by the objective lens 54 from being mixed into the tomographic image. Similarly, in the anterior segment scanning optical system of the ophthalmic apparatus of this embodiment, a dedicated objective lens 42 is arranged in the optical path L8, and no lens is arranged between the objective lens 42 and the eye E, and no lens is arranged between the two-dimensional scanner 32 and the objective lens 42. Therefore, the lens power (refractive power) required for scanning the anterior segment with light can be imparted by the objective lens 42. As a result, the angle of incidence of light on the objective lens 42 can be adjusted, and light reflected by the objective lens 42 can be prevented from being mixed into the tomographic image.

[0040] In addition, if a common objective lens is arranged in the optical path L12 between the subject's eye E and the dichroic mirror 44 and a relay lens is arranged in the optical path dedicated to the fundus scanning optical system as in the conventional technology, two lenses, an objective lens and a relay lens, are arranged in the light receiving system of the total refractive power measurement optical system. Therefore, the principal ray of light between the relay lens and the objective lens becomes nearly parallel to the optical axis and enters the objective lens arranged on the subject's eye side at an angle nearly perpendicular. As a result, not only the image reflected at the fundus of the subject's eye E but also the image generated by the light reflected at the surface of the opposing lens (the surface opposite the subject's eye) are mixed in as noise. For example, as shown in FIG. 10, not only the circular image located on the outermost side (the image by the light reflected at the fundus) but also the inner circular image (the image by the light reflected by the objective lens) is included. In the light receiving system of the total refractive power measuring optical system of the ophthalmic apparatus of this embodiment, the objective lens 54 is disposed in the optical path L10, and no lens is disposed between the objective lens 54 and the subject's eye E, and no lens is disposed between the two-dimensional scanner 32 and the objective lens 54. This makes it possible to prevent light reflected on the surface of the objective lens 54 from being mixed into the image captured by the refractive power measuring optical system.

[0041] In addition, in the ophthalmic apparatus of this embodiment, dichroic mirrors 30, 34, 44, and 56 are used to branch and merge the optical path of the anterior eye scanning optical system and the optical path of the fundus scanning optical system. Here, the dichroic mirror 30 (an example of the third dichroic mirror in the claims), the dichroic mirror 34 (an example of the second dichroic mirror in the claims), and the dichroic mirror 44 (an example of the first dichroic mirror in the claims) arranged in the optical path of the anterior eye scanning optical system are each configured to reflect the light of the anterior eye scanning optical system. This makes it possible to suppress the occurrence of ghost noise of the iris of the subject's eye E in the anterior eye tomographic image. That is, as shown in FIG. 11, if the light 84 of the anterior eye scanning optical system is configured to pass through the dichroic mirror DM, the light reflected on the exit surface 80 side of the dichroic mirror DM is further reflected (back surface reflected) on the entrance surface 82 side of the dichroic mirror DM, and this light 86 is irradiated to the subject's eye E. The iris of the subject's eye E has a high light reflection intensity. Therefore, as shown in Fig. 12, not only an anterior eye image formed by light 84 but also an image (ghost noise) formed by light 86 reflected by the iris is generated. In the ophthalmic apparatus of this embodiment, the dichroic mirrors 30, 34, and 44 arranged in the optical path of the anterior eye scanning optical system are configured to reflect all the light of the anterior eye scanning optical system, so that the above-mentioned ghost noise can be suppressed from being generated in the anterior eye tomographic image.

[0042] In addition, an AR coating for light of the anterior eye scanning optical system (for example, light having a central wavelength of 1.31 μm) may be applied to the back surface of the dichroic mirror 30, 34, 44. This can reduce the reflection intensity of the light of the anterior eye scanning optical system reflected by the back surface of the dichroic mirror 30, 34, 44, and can suitably suppress the occurrence of ghost noise in the anterior eye tomographic image. That is, even if the light of the anterior eye scanning optical system is reflected by the dichroic mirror, most of the light 90 incident on the surface 80 of the dichroic mirror DM (for example, 98%) becomes reflected light 92, but a part of it (for example, 2%) passes through the dichroic mirror DM and is reflected by the back surface 82 of the dichroic mirror DM as shown in FIG. 13. The light 94 reflected by the back surface 82 of the dichroic mirror DM passes through the surface 80 of the dichroic mirror DM, and the light 96 transmitted through the surface is irradiated onto the anterior eye of the subject's eye E. Therefore, if the intensity of the light 94 reflected by the back surface 82 of the dichroic mirror DM is high, ghost noise due to this reflected light 94 will occur in the anterior eye tomographic information. Therefore, by applying an AR coating (for example, 1% or less) to the back surface of the dichroic mirror 30, 34, 44 against the light of the anterior eye scanning optical system, it is possible to suitably suppress the occurrence of ghost noise in the anterior eye tomographic information.

[0043] For example, the scattering characteristics of tissues in the anterior segment are more diverse than those of the fundus, and in order to capture transparent tissues such as the cornea and the crystalline lens with sufficient contrast, the signal strength of the iris scattering is preferably at least 47 dB in terms of S / N ratio, as shown in FIG. 14, and more preferably 50 dB or more in order to capture the entire image from the crystalline lens to the cornea at once. That is, the back surface of the cornea cannot be clearly recognized in an image with an iris scattering signal strength of 45 dB in terms of S / N ratio, but the back surface of the cornea can be recognized in an image with an iris scattering signal strength of 47 dB in terms of S / N ratio, and the back surface of the cornea can be clearly recognized in an image with an iris scattering signal strength of 50 dB in terms of S / N ratio. On the other hand, if an AR coating is not applied to the back surface of the dichroic mirror DM, the intensity of the reflected light 94 due to the back reflection of the light that has passed through the dichroic mirror DM cannot be sufficiently reduced, and ghost noise of the iris occurs in the tomographic image of the anterior segment. For example, even if the dichroic mirror DM has a surface reflectance of 97% and is configured to preferentially reflect the anterior eye scanning light, if the dichroic mirror DM does not have an AR coating on its back surface, the back surface reflectance of the dichroic mirror DM will be 4%. Therefore, the back surface reflected light of the dichroic mirror DM has an extinction ratio of -44 dB relative to the front surface reflected light of the dichroic mirror DM, which results in the generation of ghost noise. On the other hand, if the dichroic mirror DM has an AR coating on its back surface, the back surface reflectance of the dichroic mirror DM will be 2% or less. Therefore, the back surface reflected light of the dichroic mirror DM has an extinction ratio of -47 dB or less relative to the front surface reflected light of the dichroic mirror DM, which can suppress ghost noise. Note that when light is transmitted through the dichroic mirror DM (as shown in FIG. 11), it becomes even more difficult to suppress ghost noise. For example, even if the surface transmittance of the dichroic mirror DM is 97% and an AR coating is applied to the back surface of the dichroic mirror DM (for example, back surface reflectance of 0.5%), the ghost signal extinction ratio due to back surface reflection of the dichroic mirror DM is only -38 dB, and ghost noise cannot be suppressed. Therefore, by applying an AR coating (2% or less) to the back surface of the dichroic mirror DM for the wavelength band of light of the anterior eye scanning optical system, the ghost signal extinction ratio due to the back surface reflection of the dichroic mirror DM can be set to -47 dB or less. In other words, the power of the light 96 reflected by the back surface 82 of the dichroic mirror DM is -47 dB or less compared to the power of the light 92 reflected by the front surface 80 of the dichroic mirror DM. This makes it possible to suppress the occurrence of ghost noise of the iris in the anterior eye tomographic image.

[0044] Here, the back surface of the dichroic mirror DM is generally coated with an AR coating for the wavelength of light transmitted. That is, when the optical system according to the present embodiment is configured, the back surface of the dichroic mirror DM is generally coated with an AR coating for the light of the fundus scanning optical system. The reason for this is that, among the light of the wavelength on the reflection side (i.e., the light of the anterior eye scanning optical system), the light components that pass through the mirror surface and are reflected on the back surface are largely reflected when passing through the mirror surface again after being reflected on the back surface, and are therefore unlikely to become noise, whereas, among the light of the wavelength on the transmission side (i.e., the light of the fundus scanning optical system), the light components that are reflected on the mirror surface and then reflected on the back surface are hardly attenuated when passing through the mirror surface after being reflected on the back surface, and are therefore likely to become noise. In addition, while the iris signal strength in the anterior segment tomographic image has an S / N ratio of 47 dB or more, the signal strength of the retinal pigment epithelium in the fundus tomographic image is about 30 dB. Therefore, even if an AR coating is not applied preferentially to the wavelength of the light that passes through the back surface of the dichroic mirror DM (i.e., the light of the fundus scanning optical system), there is no problem of ghost noise of the retinal pigment epithelium occurring in the fundus tomographic image.

[0045] In the above-mentioned embodiment, the two-dimensional scanner 32 is shared by the anterior eye scanning optical system and the fundus scanning optical system, but the present invention is not limited to such an example. For example, a dedicated two-dimensional scanner may be arranged in the anterior eye scanning optical system, and another dedicated two-dimensional scanner may be arranged in the fundus scanning optical system. In the above-mentioned embodiment, one objective lens (single lens) 42 is arranged in the anterior eye scanning optical system, but the objective lens arranged in the anterior eye scanning optical system may be configured by a combination of multiple lenses (for example, a combination of a convex lens and a concave lens or an aspheric lens, etc.) accommodated in the same lens barrel. Similarly, one objective lens 54 arranged in the fundus scanning optical system may be replaced with an objective lens composed of a combination of multiple lenses accommodated in the same lens barrel. When the objective lens part is configured by a combination of multiple lenses, these lenses may be bonded together so that the number of interfaces with air is minimized.

[0046] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. [Explanation of symbols]

[0047] 26: Anterior segment light source 32: 2D scanner 34, 40, 44, 56: Dichroic mirror 42,54: Objective lens 76: Fundus light source

Claims

1. a first light source that outputs a first light; a second light source that outputs a second light; a first scanning optical system that scans the first light output from the first light source over a first range of the subject's eye; a second scanning optical system that scans the second light output from the second light source over a second range of the subject's eye, the second range being different from the first range; a first interferometer that acquires tomographic information of the first range based on a first interference light obtained from a reflected light of the first light from the subject's eye; a second interferometer that acquires tomographic information of the second range based on a second interference light obtained from a reflected light of the second light from the subject's eye; an observation port facing the subject's eye; a first dichroic mirror that reflects the first light and transmits the second light; Equipped with a central wavelength of the first light is different from a central wavelength of the second light, the first scanning optical system includes a first objective lens unit that irradiates the first light onto the first range of the subject's eye, the second scanning optical system includes a second objective lens unit that irradiates the second light onto the second range of the subject's eye, the first light is transmitted through the first objective lens portion while not being transmitted through the second objective lens portion; the second light does not pass through the first objective lens portion, but passes through the second objective lens portion; a first optical path that is an optical path of the first light includes an overlapping section that overlaps with a second optical path that is an optical path of the second light, and a first non-overlapping section that does not overlap with the second optical path, The second optical path includes the overlapping section and a second non-overlapping section that does not overlap with the first optical path, the first objective lens portion is disposed in the first non-overlapping section, the second objective lens portion is disposed in the second non-overlapping section, the first area is an anterior segment of the subject's eye, the second area is a fundus of the subject's eye, The overlapping section includes a first overlapping section including a section connecting the subject's eye and the viewing aperture, the first dichroic mirror is disposed at a first position where the first overlapping section branches into the first non-overlapping section and the second non-overlapping section, An ophthalmic apparatus, wherein an AR coating (Anti Reflection Coating) is applied to a back surface of the first dichroic mirror for the wavelength band of the first light out of the wavelength band of the first light and the wavelength band of the second light.

2. the first scanning optical system includes a first scanner that scans the first light output from the first light source, the second scanning optical system includes a second scanner that scans the second light output from the second light source, the first scanner is disposed in the first non-overlapping section; The ophthalmic apparatus according to claim 1 , wherein the second scanner is disposed in the second non-overlapping section.

3. a scanner that scans the first light output from the first light source and scans the second light output from the second light source, the scanner is disposed in the overlapping section and is shared by the first scanning optical system and the second scanning optical system; the first objective lens unit is disposed between the scanner and the subject's eye, The ophthalmic apparatus according to claim 1 , wherein the second objective lens unit is disposed between the scanner and the subject's eye.

4. the overlapping section includes a second overlapping section including a section connecting the scanner and a second position where the first non-overlapping section and the second non-overlapping section join or branch off, a second dichroic mirror disposed at the second position; The ophthalmic apparatus according to claim 3 , wherein the second dichroic mirror reflects the first light and transmits the second light.

5. The ophthalmic apparatus according to claim 4 , wherein a rear surface of the second dichroic mirror is provided with an AR (Anti Reflection Coating) for the wavelength band of the first light.

6. a third dichroic mirror is further disposed at a third position different from the second position among the positions at both ends of the second overlapping section, The ophthalmic apparatus according to claim 4 , wherein the third dichroic mirror reflects the first light and transmits the second light.

7. The ophthalmic apparatus according to claim 6 , wherein a rear surface of the third dichroic mirror is provided with an AR (Anti Reflection Coating) for the wavelength band of the first light.

8. a first light source that outputs a first light; a second light source that outputs a second light; a first scanning optical system that scans the first light output from the first light source over a first range of the subject's eye; a second scanning optical system that scans the second light output from the second light source over a second range of the subject's eye, the second range being different from the first range; a first interferometer that acquires tomographic information of the first range based on a first interference light obtained from a reflected light of the first light from the subject's eye; a second interferometer that acquires tomographic information of the second range based on a second interference light obtained from a reflected light of the second light from the subject's eye; Equipped with the first area is an anterior segment of the subject's eye, the second area is a fundus of the subject's eye, a central wavelength of the first light is different from a central wavelength of the second light, a first optical path that is an optical path of the first light includes an overlapping section that overlaps with a second optical path that is an optical path of the second light, and a first non-overlapping section that does not overlap with the second optical path, The second optical path includes the overlapping section and a second non-overlapping section that does not overlap with the first optical path, The apparatus further includes an observation port facing the subject's eye, The overlapping section includes a first overlapping section including a section connecting the subject's eye and the viewing aperture, The optical system further includes a first dichroic mirror disposed at a first position where the first overlapping section branches into the first non-overlapping section and the second non-overlapping section, the first dichroic mirror reflects the first light while transmitting the second light; An ophthalmic apparatus, wherein an AR coating (Anti Reflection Coating) is applied to a back surface of the first dichroic mirror for the wavelength band of the first light out of the wavelength band of the first light and the wavelength band of the second light.

Images