Ophthalmologic measuring device and attachment used in ophthalmologic measuring device

Abstract

To provide an ophthalmologic measuring device and an attachment used in an ophthalmologic measuring device capable of maintaining measurement accuracy while achieving cost reduction.SOLUTION: An ophthalmologic measuring device for measuring eye characteristics of an eye to be examined includes a projection unit having a light source for projecting an index light flux on the cornea of an eye to be examined, a pattern forming member for forming the index light flux from the light source into a pattern, and a reflection member disposed between the light source and the pattern forming member. The index light flux from the light source is reflected in a direction away from the eye to be examined by the reflection member, reflected in a direction approaching the eye to the examined in the projection unit, and guided to the eye to be examined through the pattern forming member so that a pattern index is projected on the cornea.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an ophthalmic measurement device that measures ocular characteristics of a subject's eye, and an attachment used in the ophthalmic measurement device. [Background technology]

[0002] 2. Description of the Related Art There is known an ophthalmic measurement apparatus that projects a pattern index onto the cornea of ​​a subject's eye and measures the corneal shape as one of the eye characteristics. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-93249 A Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, there is a demand for low-cost ophthalmic measurement devices in consideration of ease of introduction into hospitals and facilities, etc. On the other hand, for example, in measuring the corneal shape of a subject's eye, it is necessary to project a pattern index with a constant light amount and maintain measurement accuracy.

[0005] In view of the above problems, the present disclosure has as its technical object to provide an ophthalmic measurement device that can maintain measurement accuracy while achieving cost reduction, and an attachment for use with the ophthalmic measurement device. [Means for solving the problem]

[0006] In order to solve the above problems, the present disclosure is characterized by having the following configuration.

[0007] The ophthalmic measurement device disclosed herein is an ophthalmic measurement device that measures the ocular characteristics of a test eye, and is equipped with a projection unit having a light source for projecting an index light beam onto the cornea of ​​the test eye, a pattern forming member for forming the index light beam from the light source into a pattern, and a reflecting member arranged between the light source and the pattern forming member, and is characterized in that the index light beam from the light source is reflected by the reflecting member in a direction away from the test eye, reflected within the projection unit in a direction approaching the test eye, and guided to the test eye via the pattern forming member, thereby projecting a pattern index onto the cornea. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is an external view of the ophthalmic measurement device. [Diagram 2] 2 is a schematic diagram illustrating an optical system and a control system of the ophthalmic measurement apparatus. [Diagram 3] 13 is an example of the subject-side housing surface. [Figure 4] 1 is an example of a member disposed inside a housing. [Diagram 5] FIG. 2 is a schematic diagram illustrating the internal configuration of a housing. [Figure 6] 3 is an example of an arrangement of components inside a housing. [Figure 7] 13 is a diagram showing an example of a modified arrangement of a reflective member and a diffusing member inside a housing. [Figure 8] This is an example of an attachment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Summary> An overview of an ophthalmic measurement device according to an embodiment of the present disclosure will be described. The items classified in <> below can be used independently or in conjunction with each other.

[0010] The ophthalmic measurement device of this embodiment is a device that measures the ocular characteristics of the test eye. For example, the ocular characteristics of the test eye may be ocular refractive power, axial length, corneal shape, etc. The ophthalmic measurement device of this embodiment may be a device to which an attachment for measuring the ocular characteristics of the test eye can be attached. For example, the attachment may be used to obtain a second ocular characteristic different from a first ocular characteristic obtained when the attachment is not attached. As an example, the attachment may be an attachment that projects a measurement index for obtaining a corneal shape distribution toward the cornea of ​​the test eye.

[0011] The ophthalmologic apparatus of this embodiment may include a projection unit (e.g., the projection unit 20). For example, the projection unit may be configured with a light source, a pattern forming member, a reflecting member, and the like. Of course, for example, the projection unit may be configured to include, in addition to these members, members different from these members. As an example, it may be a diffusion member, etc.

[0012] The ophthalmic measurement apparatus of this embodiment may include a light source (for example, a point light source 162) for projecting an index light beam onto the cornea of ​​the subject's eye. For example, the light source may be one light source or multiple light sources. For example, the multiple light sources may be arranged concentrically around the optical axis, or may be arranged in any number of meridian directions (radial directions) around the optical axis.

[0013] The ophthalmic measurement device of this embodiment may include a pattern forming member (e.g., slit member 10) for forming the index light beam from the light source in a pattern. For example, the pattern forming member may have a transmission portion that transmits the index light beam and a light shielding portion (e.g., region R1) that blocks the index light beam. For example, the transmission portion may be formed by a thin film or the like that transmits the wavelength of the index light beam from the light source. Also, for example, the transmission portion may be formed by a through hole such as a slit (e.g., slit 12). For example, the light shielding portion may be formed by a thin film or the like that blocks the wavelength of the measurement light beam from the light source. Also, for example, the light shielding portion may be formed as a region different from the aforementioned through hole. For example, the pattern forming member may form the index light beam in at least one pattern such as a dot, a line, a grid, a ring, etc., by the transmission portion and the light shielding portion.

[0014] The ophthalmic measurement device of this embodiment may include a reflective member (e.g., reflective member 13, reflective member 250) disposed between the light source and the pattern forming member. For example, the reflective member may be a member having a reflection characteristic for the wavelength of the index light beam from the light source. For example, the reflective member may be a member that specularly reflects the index light beam, a member that retroreflects it, or a member that diffusely reflects it. As an example, the reflective member may be a total reflection mirror, a half mirror, a retroreflection sheet, a metal plate, a white plate, or the like. Also, for example, the reflective member may be a member having a higher reflectance than a diffusing member described later.

[0015] For example, the reflecting member may be disposed close to the pattern forming member, and the distance from the reflecting member to the pattern forming member may be set shorter than the distance from the light source to the reflecting member, which makes it difficult for the reflected light beam of the index light beam to be absorbed by the pattern forming member, thereby suppressing a decrease in the amount of light beam passing through the pattern forming member.

[0016] Also, for example, the reflective member may be disposed adjacent to the pattern forming member. For example, by blocking the pattern forming member with the reflective member, it is possible to minimize the reduction in the amount of light passing through the pattern forming member.

[0017] For example, the pattern forming member and the reflective member may be provided separately. Also, for example, the pattern forming member and the reflective member may be combined. In this case, for example, a member equivalent to the reflective member can be formed by applying paint or forming a thin film on the back surface of the pattern forming member.

[0018] For example, when the ophthalmic measuring device includes only the light source and the pattern forming member, the light amount of the index light beam passing through the pattern forming member can be made constant by increasing the output of the light source or by using multiple light sources. However, for example, when the number of light sources is reduced to reduce the cost of the ophthalmic measuring device, it is difficult to maintain the light amount if the output of the light source is already at a maximum. Therefore, for example, when a reflecting member is arranged in addition to the light source and the pattern forming member as in the present embodiment, the light amount of the index light beam can be maintained even if the number of light sources is reduced. For example, at this time, the index light beam from the light source is reflected by the reflecting member in a direction away from the test eye, reflected in the projection unit in a direction approaching the test eye, and guided to the test eye through the pattern forming member. For example, by increasing the illuminance of the index light beam by reflecting it back with the reflecting member, the pattern index projected on the cornea becomes clearer as a result, and the detection accuracy and measurement accuracy are improved.

[0019] The ophthalmic measurement device of the present embodiment may include a diffusing member between the light source and the pattern forming member for diffusing the index light beam. For example, the diffusing member may be a member having a diffusing characteristic for the wavelength of the index light beam from the light source. For example, the diffusing member may be a member that refracts the index light beam at a predetermined diffusion angle. As an example, the diffusing member may be a ground glass plate, or a glass plate or an acrylic plate with a milky white film. In addition, for example, the diffusing member may be a member having a higher transmittance than the reflecting member. For example, by disposing a diffusing member in the optical path of the index light beam, the index light beam can be passed uniformly from the pattern forming member, and the detection accuracy and measurement accuracy of the pattern index are improved.

[0020] For example, the diffusion member may be disposed between the light source and the reflecting member, and the index light beam from the light source may be diffused by the diffusion member and then reflected by the reflecting member, reflected in the projection unit in a direction approaching the test eye, and guided through the pattern forming member to project the pattern index onto the cornea. Also, for example, the diffusion member may be disposed between the pattern forming member and the reflecting member, and the index light beam from the light source may be diffused by the diffusion member and then reflected by the reflecting member, reflected in the projection unit in a direction approaching the test eye, and guided through the pattern forming member to project the pattern index onto the cornea.

[0021] The present disclosure is not limited to application to the ophthalmic measurement device described in the present embodiment. For example, the present disclosure may be applied to an attachment used in an ophthalmic measurement device that measures the eye characteristics of a test eye. In this case, the ophthalmic measurement device includes a light source that projects an index light beam onto the cornea of ​​the test eye, and the attachment includes a pattern forming member that forms the index light beam from the light source into a pattern, and a reflecting member that is disposed between the light source and the pattern forming member. The index light beam from the light source may be reflected by the reflecting member in a direction away from the test eye, reflected in the attachment in a direction approaching the test eye, and guided to the test eye via the pattern forming member to project a pattern index onto the cornea. Of course, the attachment may include a diffusing member for diffusing the index light beam between the light source and the pattern forming member.

[0022] <Example> An example of an ophthalmic measurement device according to this embodiment will be described below. Here, the left-right direction of the ophthalmic measurement device is represented as the X direction, the up-down direction as the Y direction, and the front-rear direction as the Z direction.

[0023] <Device configuration> FIG. 1 is an external view of an ophthalmic measurement device 1. The ophthalmic measurement device 1 includes a base 2, a face support unit 3, a drive unit 4, a measurement unit 5, a display unit 75, an operation unit 76, and the like. The face support unit 3 is fixed to the base 2 and supports the face of the subject. The drive unit 4 drives the measurement unit 5 in the XYZ directions relative to the base 2. The display unit 75 displays various information (e.g., an image of the anterior segment of the subject's eye, measurement results of the subject's eye, etc.). The operation unit 76 performs various settings. In this embodiment, the display unit 75 with a touch panel also serves as the operation unit 76.

[0024] 2 is a schematic diagram of the optical system and control system of the ophthalmic measurement device 1. The measurement unit 5 includes a measurement optical system 100, a fixation target optical system 130, an observation optical system 150, and an index projection optical system 160. The measurement unit 5 also includes half mirrors 116 and 117 that branch and combine the optical paths of the optical systems, and an objective lens 118. The measurement unit 5 also includes a focus adjustment unit 125 and a fixation target adjustment unit 135 that drive a portion of the optical systems.

[0025] <Measurement optical system> The measurement optical system 100 objectively measures the ocular refractive power (e.g., spherical power, cylindrical power, astigmatism axis angle, etc.) of the subject's eye E. The measurement optical system 100 has a light projecting optical system 100a and a light receiving optical system 100b. The light projecting optical system 100a includes a light source 111, a relay lens 112, a hole mirror 114, a prism 115, an objective lens 118, etc. The light source 111 is in an optically conjugate position with the fundus. The opening of the hole mirror 114 is in an optically conjugate position with the pupil. The prism 115 is disposed at a position away from the position optically conjugate with the pupil, and the light beam passing through the prism 115 is decentered with respect to the optical axis. The prism 115 is driven to rotate around the optical axis by a drive unit 119. Note that instead of the prism 115, a parallel flat plate may be disposed obliquely on the optical axis.

[0026] The light receiving optical system 110b includes an objective lens 118, a prism 115, a hole mirror 114, a relay lens 120, a light receiving aperture 121, a collimator lens 122, a ring lens 123, and an image sensor 124. The light receiving aperture 121 is in an optically conjugate positional relationship with the fundus. The ring lens 123 is in an optically conjugate positional relationship with the pupil. The image sensor 124 is in an optically conjugate positional relationship with the fundus.

[0027] In such a measurement optical system 100, the measurement light beam emitted from the light source 111 passes through the relay lens 112, the hole mirror 114, and the prism 115, is reflected by the half mirrors 116 and 117, and is further projected as a spot-shaped light beam on the fundus through the objective lens 118. As a result, a point light source image is formed on the fundus. At this time, the prism 115 is rotated around the optical axis, and the pupil projection image (projection light beam on the pupil) at the opening of the hole mirror 114 is eccentrically rotated at high speed. The reflected light beam reflected by the fundus is reflected by the hole mirror 114 through the objective lens 118, the half mirrors 117 and 116, and the prism 115. Furthermore, the reflected light beam passes through the relay lens 120 and is focused at the position of the light receiving diaphragm 121, and is imaged as a ring-shaped image (ring image) on the image sensor 124 by the collimator lens 122 and the ring lens 123. An output signal from the image sensor 124 is input to the control unit 70, which calculates the eye refractive power.

[0028] The measurement optical system 100 may be an optical system different from that in this embodiment, as long as it has a light projecting optical system that projects a measurement light beam on the fundus of the subject's eye E and a light receiving optical system that receives the reflected light beam of the measurement light beam reflected by the fundus. For example, the measurement optical system 100 may be an optical system that projects a spot index on the fundus and detects the reflected light beam of the spot index on the fundus using a Shack-Hartmann sensor. Also, for example, the measurement optical system 100 may be an optical system of a phase difference type that projects a slit on the subject's eye E.

[0029] <Focus adjustment section> The focus adjustment unit 125 adjusts the focus position of the measurement optical system 100 with respect to the subject's eye E. For example, the focus adjustment unit 125 includes a drive unit 126 such as a motor, and can move the light source 111, the light receiving aperture 121, the collimator lens 122, the ring lens 123, and the image sensor 124 integrally along the optical axis.

[0030] The focus adjustment unit 125 is moved according to the ocular refractive power of the subject's eye E, so that the light source 111 and the image sensor 124 can be made fundus conjugate. For example, when the subject's eye is hyperopic, the image sensor 124 and the like are moved in a direction approaching the subject's eye, and when the subject's eye is myopic, the image sensor 124 and the like are moved in a direction away from the subject's eye. At this time, regardless of the movement of the focus adjustment unit 125, the hole mirror 114 and the ring lens 123 are pupil conjugate at a constant magnification. For example, the movement position of the focus adjustment unit 125 is detected by a potentiometer or the number of steps of a motor, or the like.

[0031] <Fixation target optical system> The fixation target optical system 130 presents a fixation target to the subject's eye E. The fixation target optical system 130 includes a light source 131, a fixation target plate 132, light projecting lenses 133 and 134, an objective lens 118, and the like. The fixation target plate 132 is used when the subject's eye E is fixated and its ocular refractive power is measured. The fixation target plate 132 may be disposed at a fundus conjugate position.

[0032] A fixation target is presented by illuminating a fixation target plate 132 with a light source 131. A fixation light beam from the light source 131 passes through the fixation target plate 132, light projecting lenses 133 and 134, and the half mirror 116, is reflected by the half mirror 117, and further passes through the objective lens 118 to reach the fundus.

[0033] <Fixation target adjustment unit> The fixation target adjustment unit 135 moves the presentation position of the fixation target with respect to the subject's eye E. For example, the fixation target adjustment unit 135 includes a drive unit 136 such as a motor, and can move the light source 131 and the fixation target plate 132 integrally along the optical axis.

[0034] The fixation target adjustment unit 135 can change the presentation distance of the fixation target plate 132 (i.e., the presentation position of the fixation target) relative to the subject's eye E by being moved according to the ocular refractive power of the subject's eye E. In addition, the fixation target adjustment unit 135 can apply fogging or accommodation load to the subject's eye E by moving the light source 301 and the fixation target plate 302 in the optical axis direction.

[0035] <Observation optical system> The observation optical system 150 captures an image of the anterior segment of the subject's eye E. The observation optical system 150 includes an objective lens 118, an imaging lens 152, an imaging element 151, and the like. The imaging element 151 is in an optically conjugate positional relationship with the anterior segment of the subject's eye E, and receives a reflected light beam from the anterior segment. In this way, an image of the anterior segment of the subject's eye E (a front image of the anterior segment) is captured. An output signal from the imaging element 151 is input to the control unit 70 and the display unit 75. The observation optical system 150 also serves as an optical system for detecting an alignment target image formed on the cornea of ​​the subject's eye E, and the position of the alignment target image is detected by the control unit 70.

[0036] <Indicator projection optical system> The index projection optical system 160 projects an alignment index onto the subject's eye E. The index projection optical system 160 includes a first index projection optical system and a second index projection optical system. The first index projection optical system projects an alignment index at infinity onto the cornea of ​​the subject's eye E. The second index projection optical system projects an alignment index at finite distance onto the cornea of ​​the subject's eye E.

[0037] The first target projection optical system has a plurality of point light sources 161. The point light sources 161 emit near-infrared light. The point light sources 161 irradiate parallel light beams (approximately parallel light beams). For example, the point light sources 161 are arranged on concentric circles based on the optical axis, so as to be symmetrical on both sides of a vertical plane passing through the optical axis. For example, by providing one point light source 161 on each side, two point image targets are projected onto the cornea.

[0038] The second index projection optical system has a plurality of point light sources 162. The point light sources 162 emit near-infrared light. The point light sources 162 irradiate a diffuse light beam. For example, a plurality of point light sources 162 are arranged on a concentric circle based on the optical axis, so as to be symmetrical with respect to a vertical plane passing through the optical axis. For example, a ring index (so-called Mayer ring index) is projected on the cornea by arranging a large number of point light sources 162 in a ring shape.

[0039] In this embodiment, the working distance may be adjusted by moving the measurement unit 5 in the forward / backward direction so that the Purkinje image by the point light source 161 and the Mayer ring image by the point light source 162 are captured at a predetermined ratio. In this embodiment, the point light source 162 can be used as an anterior segment illumination for illuminating the anterior segment, a measurement index for measuring the corneal shape, etc.

[0040] 3 is an example of the housing surface on the subject side (i.e., the measurement unit 5 seen from the subject side). A projection unit 20 is disposed in front of the subject's eye E. A first target projection optical system (e.g., a point light source 161) is disposed in front of the subject's eye E via a slit member 10 fixed to the housing. A measurement optical system 100, a fixation target optical system 130, an observation optical system 150, etc. are disposed in front of the subject's eye E via a window member 7 that covers the opening 11 of the slit member 10. A second target projection optical system (e.g., a point light source 162) is disposed in front of the subject's eye E via a window member 6 fixed to the housing.

[0041] FIG. 4 shows an example of members arranged inside the housing, and FIG. 5 is a schematic diagram of the inside of the housing. The projection unit 20 is composed of a slit member 10, a reflecting member 13, a diffusing member 16, a substrate 18 (point light source 162), and the like. In the projection unit 20, the members are arranged in the order of the reflecting member 13, the diffusing member 16, and the substrate 18, from the slit member 10 toward the back. For example, the slit member 10 has an opening 11 in the center and a ring-shaped slit 12 around the opening 11. For example, the reflecting member 13 is arranged on the back surface of the slit member 10. For example, the reflecting member 13 has an opening 14 in the center and a ring-shaped slit 15 around the opening 14. For example, the reflecting member 13 may be a member having a reflective property (for example, a metal plate, a mirror, or the like). For example, the diffusing member 16 is arranged on the back surface of the reflecting member 13. For example, the diffusing member 16 has an opening 17 in the center. For example, the diffusion member 16 may be a member having scattering properties (for example, ground glass or a film). For example, the substrate 18 has an opening 19 in the center. For example, point light sources 161 and 162 are fixed to the substrate 18. For example, the substrate 18 may be a member having reflective properties.

[0042] In this embodiment, the reflective member 13, the diffusing member 16, and the point light source 162 are covered by the slit member 10 and the substrate 18. Furthermore, the distance D2 from the reflective member 13 to the slit member 10 is set to be shorter than the distance D1 from the point light source 162 to the reflective member 13. For example, here, the reflective member 13 is disposed adjacent to the slit member 10, so that the distance D2 is set to be shorter. Furthermore, the distance from the diffusing member 16 to the slit member 10 is set to be shorter than the distance from the point light source 162 to the diffusing member 16. For example, here, the diffusing member 16 is disposed adjacent to the reflective member 13, so that the distance is set to be shorter.

[0043] The slit 12 of the slit member 10 and the slit 15 of the reflecting member 13 have the same shape and size. The openings of each member have the same shape and size. For example, the optical axis of the measurement optical system 100 passes through the center of these openings.

[0044] For example, in the second index projection optical system, the index light beam emitted from the light source 162 is diffused by passing through the diffusion member 16, and then reflected by the reflection member 13 in a direction away from the subject's eye. Next, for example, the index light beam is reflected by the substrate 18 or the like in a direction approaching the subject's eye, passes through the diffusion member 16 again, and is reflected by the reflection member 13. For example, the index light beam is repeatedly reflected by the reflection member 13, so that the illuminance in the space Sp increases, and a part of the index light beam passes through the reflection member 13 and the slit of the slit member 10, so that the light is appropriately guided to the subject's eye.

[0045] In this configuration, the region R1 different from the slit 12 of the slit member 10 is blocked by the region R2 different from the slit 15 of the reflecting member 13, so that the absorption of the index light beam by the region R1 is suppressed. Also, in this configuration, the index light beam passes through the diffusing member 16, so that the ring index projected on the cornea can be smoothed.

[0046] <Control Unit> Returning to FIG. 2, the control unit 70 includes a CPU (processor), a RAM, a ROM, etc. The CPU controls the driving of each part in the ophthalmic measurement device 1. The RAM temporarily stores various information. The ROM stores various programs executed by the CPU, etc. The control unit 70 may be configured by multiple control units (i.e., multiple processors).

[0047] The control unit 70 is electrically connected to the driving unit 4, the display unit 75, the operation unit 76, a non-volatile memory 72 (hereinafter, memory 72), etc. In addition, the control unit 70 is electrically connected to the light sources, the image pickup devices, the driving units, etc., that the measurement unit 5 includes.

[0048] The memory 72 is a non-transient storage medium capable of retaining stored contents even when the power supply is cut off. For example, a hard disk drive, a flash ROM, a USB memory, etc. can be used as the memory 72. The memory 72 may store measurement results of the subject's eye (for example, corneal shape, eye refractive power, etc.).

[0049] <Control action> The control operation of the ophthalmic measurement apparatus 1 will be described.

[0050] The examiner instructs the subject to support the face of the subject on the face support unit 3 and look at the fixation target projected by the fixation target optical system 130. When the subject is ready, the control unit 70 starts auto-alignment. For example, the control unit 70 turns on the point light sources 161 and 162 of the target projection optical system 160. As a result, two point image targets by the point light source 161 and a double ring target by the point light source 162 are projected onto the anterior segment of the subject's eye. In addition, the control unit 70 captures an anterior segment image including the point image target image and the ring target image by the imaging element 151 of the observation optical system 150.

[0051] The control unit 70 detects the alignment state of the measurement unit 5 with respect to the subject's eye based on the imaging signal from the observation optical system 150. For example, the control unit 70 detects a ring index image and calculates the center position of the ring index image to control the driving in the XY direction by the driving unit 4. As an example, the control unit 70 moves the measurement unit 5 so that the center position of the ring index image coincides with the optical axis. In addition, for example, the control unit 70 controls the driving in the Z direction by the driving unit 4 based on the image ratio of the point image index image and the ring index image. As an example, the control unit 70 compares the distance a between the two point image index images and the width b of the ring index image, and determines that the focus in the Z direction is matched when the length of the distance a and the width b become a predetermined ratio. Note that the above-mentioned reflecting member 13 and diffusing member 16 reflect a clear and smoothed ring index image in the anterior eye image, thereby improving the detection accuracy.

[0052] When the alignment between the eye E and the measurement unit 5 is completed, the control unit 70 measures the corneal shape of the eye E. The control unit 70 outputs a trigger signal upon completion of the alignment, captures an anterior eye image, and obtains an anterior eye image including a point image and a ring image as a still image, and stores the image in the memory 72. Next, the control unit 70 analyzes the anterior eye image, and calculates the corneal shape in the circumferential region of the inner ring image and the circumferential region of the outer ring image based on the image height of the ring image, etc. For example, the corneal shape may be the curvature of the cornea in the maximal meridian direction and the minor meridian direction, the astigmatism axis angle of the cornea, etc. In the case of an eye with corneal astigmatism, the ring image has an elliptical shape, so that the astigmatism axis angle can also be obtained by detecting the major axis direction and the minor axis direction. The control unit 70 stores the measurement result in the memory 72.

[0053] Furthermore, the control unit 70 may measure the ocular refractive power of the test eye E after completing the measurement of the corneal shape of the test eye E. The control unit 70 places the fixation target plate 132 at a predetermined position relative to the test eye, irradiates the measurement light beam from the light source 111 of the measurement optical system 100, and causes the image sensor 124 to capture the reflected light beam of the measurement light beam as a ring image. The control unit 70 also thins the ring image, obtains the ocular refractive power in each meridian direction based on the position of the ring image in each meridian direction, and performs a predetermined process on these ocular refractive powers to obtain the ocular refractive power of the test eye. The control unit 70 stores the measurement result in the memory 75.

[0054] When the measurement of the corneal shape of the eye E and the measurement of the eye refractive power of the eye E are completed, the control unit 70 causes the display unit 75 to display the respective measurement results.

[0055] As described above, for example, the ophthalmic measurement device of this embodiment includes a projection unit having a light source for projecting an index light beam onto the cornea of ​​the subject's eye, a pattern forming member for forming the index light beam from the light source into a pattern, and a reflecting member disposed between the light source and the pattern forming member, and the index light beam from the light source is reflected by the reflecting member in a direction away from the subject's eye, reflected in the projection unit in a direction toward the subject's eye, and guided to the subject's eye via the pattern forming member to project a pattern index onto the cornea. For example, with this configuration, the amount of light passing through the pattern forming member can be increased compared to a case where a reflecting member is not disposed. As a result, the pattern index projected onto the cornea becomes clear, and the detection accuracy and measurement accuracy can be improved. With this configuration, a constant amount of light can be maintained even when the number of light sources is reduced from that of the conventional device in order to reduce costs, etc.

[0056] Also, for example, in the ophthalmic measurement device of this embodiment, the reflecting member is disposed close to the pattern forming member, and the distance from the reflecting member to the pattern forming member is set shorter than the distance from the light source to the reflecting member. For example, this makes it difficult for the reflected light beam of the index light beam to be absorbed by the pattern forming member, and it is possible to suppress a decrease in the amount of light beam passing through the pattern forming member. Also, for example, when providing slits or the like in the reflecting member in accordance with the slits or the like in the pattern forming member, it becomes easier to determine the position taking into account the distance between the members.

[0057] In addition, for example, in the ophthalmic measurement device of this embodiment, the reflecting member is adjacent to the pattern forming member. For example, when the pattern forming member is blocked in this manner using the reflecting member, the reduction in the amount of light passing through the pattern forming member can be minimized. In addition, for example, the slits provided in the reflecting member can be simply configured since they may be disposed at positions that coincide with the slits of the pattern forming member.

[0058] Furthermore, for example, the ophthalmic measurement device of this embodiment includes a diffusion member between the light source and the pattern forming member for diffusing the index light beam. For example, such a configuration allows the light beam to pass through the pattern forming member more uniformly than when no diffusion member is provided. As a result, the pattern index projected onto the cornea becomes smooth, and detection accuracy and measurement accuracy can be improved.

[0059] <Example of transformation> In this embodiment, the configuration in which the reflective member 13 is provided separately from the slit member 10 has been described as an example, but the present invention is not limited to this. For example, the slit member 10 may be configured to serve as both the reflective member 13 and the slit member 10. In this case, for example, the back surface of the slit member 10 may be painted white to replace the reflective member 13.

[0060] In this embodiment, the substrate 18 is made of a material having reflective properties, but the present invention is not limited to this. For example, the reflectance of the index light beam by the substrate 18 may be increased by applying a white coating or the like to the substrate 18.

[0061] In this embodiment, the slits 12 of the slit member 10 and the slits 15 of the reflecting member 13 are the same size, but the present invention is not limited to this. For example, the slits may be different sizes. For example, the size of the slits may be increased or decreased as appropriate depending on the distance D2 between the slit member 10 and the reflecting member 13.

[0062] In this embodiment, the reflection characteristic of the reflection member 13 is uniform, but the present invention is not limited to this. For example, the reflection characteristic may be changed depending on the area of ​​the reflection member 13. In this case, the reflectance may be different for each area of ​​the reflection member 13, or the reflectance may be changed according to the change in the area of ​​the reflection member 13. As an example, the reflectance may be set to increase from the center of the reflection member toward the outside. When white paint or the like is applied to the back surface of the slit member 10, the reflectance may be changed by changing the color tone depending on the area of ​​the slit member 10.

[0063] In this embodiment, as an example of setting the distance D2 from the reflecting member 13 to the slit member 10 to be shorter than the distance D1 from the point light source 162 to the reflecting member 13, a configuration in which the slit member 10 and the reflecting member 13 are disposed adjacent to each other has been described, but this is not limiting. The slit member 10 and the reflecting member 13 do not necessarily have to be disposed adjacent to each other. The reflecting member 13 and the diffusing member 16 do not necessarily have to be disposed adjacent to each other.

[0064] FIG. 6 is an example of the arrangement of each member inside the housing. Here, each member is illustrated in a simplified manner. For example, as shown in FIG. 6(a), the reflecting member 13 may be arranged adjacent to the back surface of the slit member 10, and the diffusing member 16 may be arranged away from the back surface of the reflecting member 13. Also, as shown in FIG. 6(b), the reflecting member 13 may be arranged away from the back surface of the slit member 10, and the diffusing member 16 may be arranged adjacent to the back surface of the reflecting member 13. Also, as shown in FIG. 6(c), the reflecting member 13 may be arranged away from the back surface of the slit member 10, and the diffusing member 16 may be arranged away from the back surface of the reflecting member 13. For example, even when each member is arranged in this manner, the index light beam can be guided to the subject's eye with a constant light amount by making the distance D2 shorter than the distance D1. It is preferable to set the distance D2 as short as possible so that the region R1 of the slit member 10 is blocked and the index light beam does not spread between the slit member 10 and the reflecting member 13.

[0065] In this embodiment, the reflective member 13 is disposed in front of the subject's eye and the diffusing member 16 is disposed at the back inside the housing, but the present invention is not limited to this. For example, the reflective member 13 and the diffusing member 16 may be disposed in the opposite order.

[0066] 7 shows an example of a modified arrangement of the reflecting member 13 and the diffusing member 16 inside the housing. Here, each member is also shown in a simplified form. For example, as shown in FIG. 7(a), the diffusing member 16 may be disposed adjacent to the rear surface of the slit member 10, and the reflecting member 13 may be disposed adjacent to the rear surface of the diffusing member 16. For example, even in such a configuration in which the diffusing member 16 is sandwiched between the slit member 10 and the reflecting member 13 and the slit member 10 and the reflecting member 13 are spaced apart, the region R1 of the slit member 10 can be indirectly blocked by the reflecting member 13, so that the index light beam is appropriately guided to the subject's eye.

[0067] Of course, for example, as shown in FIG. 7(b), the diffusion member 16 may be disposed adjacent to the back surface of the slit member 10, and the reflection member 13 may be disposed away from the back surface of the diffusion member 16. For example, as shown in FIG. 7(c), the diffusion member 16 may be disposed away from the back surface of the slit member 10, and the reflection member 13 may be disposed adjacent to the back surface of the diffusion member 16. For example, as shown in FIG. 7(d), the diffusion member 16 may be disposed away from the back surface of the slit member 10, and the reflection member 13 may be disposed away from the back surface of the diffusion member 16. Even in the case of the configuration shown in FIG. 7(b) to (d), the absorption of the index light beam by the region R1 of the slit member 10 is easily suppressed by setting the distance D2 shorter than the distance D1, and as a result, the light amount of the index light beam is maintained.

[0068] In this embodiment, the configuration in which the reflecting member 13 is disposed inside the housing of the ophthalmic measurement device 1 has been described as an example, but the present invention is not limited to this. For example, the reflecting member may be disposed in an attachment that can be attached to and detached from the ophthalmic measurement device 1. As an example, the attachment may be an index projection attachment that is a cone-shaped index projector.

[0069] 8 is an example of the attachment 200. The attachment 200 includes a conical inner tube portion 210 and an outer shell portion 220. An opening 211 on the rear end side of the inner tube portion 210 is disposed in the window member 7. An opening 212 on the front end side of the inner tube portion 210 has a shape that is wider than the opening 211 on the rear end side. The rear end side of the outer shell portion 220 has a shape that accommodates the slit 12 of the slit member 10. The front end side of the outer shell portion 220 has a tapered shape. For example, the space between the inner tube portion 210 and the outer shell portion 220 is a hollow light-transmitting portion.

[0070] A large number of slits 213 are formed in the inner tube portion 210. The slits 213 are formed in a ring shape centered on the central axis (optical axis). For example, the slits 213 become Placido ring indices projected onto the cornea. A reflecting member 250 is disposed at the boundary between the inner tube portion 210 and the outer shell portion 220. For example, the reflecting member 250 reflects the indicia light beam within the light transmitting portion.

[0071] By mounting the attachment 200 on the ophthalmic measurement device 1, the index projection optical system 160 is used as a measurement optical system for measuring the corneal shape distribution. For example, the point light source 162 is also used as a light source for projecting the Placido ring index. For example, the index light beam from the point light source 162 passes through the diffusing member 16 and the reflecting member 13, passes through the slit 12 of the slit member 10, and is emitted to the outer shell part 220. Also, for example, the index light beam is reflected by the reflecting member 250 to increase the illuminance in the light transmitting part, passes through the slit 213, and is emitted to the inner tube part 210. As a result, the Placido ring index is projected on the cornea.

[0072] Note that a dedicated light source for projecting the Placido ring index may be provided in the attachment 200 (for example, in the light transmitting section) instead of sharing the light source 162 of the index projection optical system 160. Also, a configuration may be adopted in which the reflecting member 250 is provided in the attachment 200 and the reflecting member 13 is not provided inside the housing of the ophthalmic measurement device 1.

[0073] For example, the control unit 70 turns on the point light source 162 and captures an anterior eye image including the Placido ring index image by the imaging element 151. In addition, for example, the control unit 70 may analyze the anterior eye image to obtain a corneal shape distribution, and may display this on the display unit 75 by expressing it as a color map, a contour map, or the like. [Explanation of symbols]

[0074] 5 Measuring part 10 Slit member 13 Reflective material 16 Diffusion material 70 Control section 100 Measurement optical system 130 Fixation target optical system 150 Observation Optical System 160 Index projection optical system 200 Attachments

Claims

1. An ophthalmic measurement apparatus for measuring ocular characteristics of a subject's eye, comprising: a light source for projecting a target light beam onto the cornea of ​​the subject's eye; a pattern forming member for forming the index light beam from the light source into a pattern; a reflecting member disposed between the light source and the pattern forming member; a projection unit having An ophthalmic measurement device characterized in that the index light beam from the light source is reflected by the reflecting member in a direction away from the test eye, reflected within the projection unit in a direction approaching the test eye, and guided to the test eye via the pattern forming member, thereby projecting a pattern index onto the cornea.

2. 2. The ophthalmic measurement apparatus according to claim 1, The reflecting member is disposed adjacent to the pattern forming member, 13. An ophthalmic measurement apparatus, comprising: an optical fiber for receiving an optical signal from said light source; a light source for receiving said optical fiber;

3. 3. The ophthalmic measurement apparatus according to claim 2, The ophthalmic measurement apparatus according to claim 1, wherein the reflecting member is adjacent to the pattern forming member.

4. In the ophthalmic measurement device according to any one of claims 1 to 3, An ophthalmic measurement apparatus comprising: a diffusion member for diffusing the index light beam between the light source and the pattern forming member.

5. 5. The ophthalmic measurement apparatus according to claim 4, the diffusing member is disposed between the light source and the reflecting member, An ophthalmic measurement device characterized in that the index light beam from the light source is diffused by the diffusing member, reflected by the reflecting member, and guided through the pattern forming member, thereby projecting a pattern index onto the cornea.

6. 5. The ophthalmic measurement apparatus according to claim 4, the diffusing member is disposed between the pattern forming member and the reflecting member, An ophthalmic measurement device characterized in that the index light beam from the light source is reflected by the reflecting member, diffused by the diffusing member, and guided through the pattern forming member, thereby projecting a pattern index onto the cornea.

7. An attachment for use in an ophthalmic measurement device for measuring ocular characteristics of a subject's eye, The ophthalmic measurement device includes: a light source for projecting an index light beam onto the cornea of ​​the subject's eye; The attachment comprises: a pattern forming member for forming the index light beam from the light source into a pattern; a reflecting member disposed between the light source and the pattern forming member; Equipped with An attachment characterized in that the index light beam from the light source is reflected by the reflecting member in a direction away from the test eye, reflected within the attachment in a direction approaching the test eye, and guided to the test eye via the pattern forming member, thereby projecting a pattern index onto the cornea.

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