Eye refractive power measuring device and attachment mounted on eye refractive power measuring device

Abstract

To provide an eye refractive power measuring device capable of easily measuring eye refractive power of an ocular fundus peripheral part of an eye to be examined, and an attachment mounted on the eye refractive power measuring device.SOLUTION: An eye refractive power measuring device includes: fixation target presentation means having a fixation optical system for projecting fixation light to an eye to be examined for presenting a fixation target to the eye to be examined; measuring means having a measurement optical system including a projection optical system for projecting a measurement light flux to the ocular fundus of the eye to be examined and a light reception optical system for receiving a reflection light flux generated when the measurement light flux is reflected in the ocular fundus, for objectively measuring eye refractive power of the eye to be examined; and inclination means for positioning the ocular fundus peripheral part of the eye to be examined on a measurement optical axis by inclining a visual axis of the eye to be examined with respect to the measurement optical axis of the measurement optical system. The measuring means measures the eye refractive power of the ocular fundus peripheral part of the eye to be examined in the state that the visual axis of the eye to be examined is inclined with respect to the measurement optical axis of the measurement optical system by the inclination means.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an eye refractive power measurement device that measures the eye refractive power of a test eye, and an attachment that is attached to the eye refractive power measurement device. [Background technology]

[0002] An eye refractive power measuring device is known that projects a measurement light beam onto the fundus of a subject's eye, receives the reflected light beam from the fundus with a light receiving element, and objectively measures the eye refractive power of the subject's eye based on the output of the light receiving element (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-187483 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the eye refractive power measuring device as described above, it is common to measure the eye refractive power of the central part of the fundus relative to the visual axis of the subject eye. Meanwhile, in recent years, the prevalence of myopia, especially among young people, has increased significantly, and attention has been paid to the eye refractive power of the peripheral part of the fundus of the subject eye in order to evaluate and prevent the progression of myopia.

[0005] In consideration of the above problems, the technical objective of the present disclosure is to provide an eye refraction measurement device that can easily measure the eye refraction of the peripheral part of the fundus of a test eye, and an attachment to be attached to the eye refraction measurement device. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention is characterized by having the following configuration. (1) An ocular refractive power measurement device according to a first aspect of the present disclosure has a fixation optical system that projects fixation light onto the test eye, and has a measurement optical system including a fixation target presenting means that presents a fixation target to the test eye, a light projecting optical system that projects a measurement light beam onto the fundus of the test eye, and a light receiving optical system that receives a reflected light beam of the measurement light beam reflected by the fundus, and is equipped with a measurement means that objectively measures the ocular refractive power of the test eye, and a tilting means that aligns a peripheral portion of the fundus of the test eye on the measurement optical axis by tilting the visual axis of the test eye relative to the measurement optical axis of the measurement optical system, and is characterized in that the measurement means measures the ocular refractive power of the peripheral portion of the fundus of the test eye while the visual axis of the test eye is tilted by the tilting means relative to the measurement optical axis of the measurement optical system. (2) An attachment according to a second aspect of the present disclosure is an attachment to be attached to an eye refraction measurement device, the eye refraction measurement device having a first measurement optical system that objectively measures the eye refraction at the center of the fundus of the test eye, and the attachment is characterized in that it has a transformation optical system for converting the first measurement optical system into a second measurement optical system that objectively measures the eye refraction at the peripheral part of the fundus of the test eye. [Brief description of the drawings]

[0007] [Figure 1] 1 is an external configuration diagram of an eye refractive power measuring device. [Diagram 2] FIG. 2 is an enlarged configuration diagram of an attachment portion. [Diagram 3] FIG. 2 is a schematic diagram illustrating the configuration of an optical system of a first measurement unit. [Figure 4] FIG. 4 is a schematic diagram illustrating the configuration of an optical system of a second measurement unit. [Diagram 5] 1 is a diagram showing the relationship between the visual axis of a test eye E and a measurement optical axis. [Figure 6] 1 is an example of a display screen displayed on a display unit. [Figure 7] FIG. 2 is a schematic diagram illustrating the configuration of a fixation optical system. [Figure 8] 1A and 1B are diagrams illustrating acquisition of gaze information of a subject. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] <Summary> An embodiment of the eye refractive power measuring device according to the present embodiment will be described. The items classified in < > below can be used independently or in conjunction with each other.

[0009] <Method of presenting fixation target> The eye refractive power measuring device of this embodiment may include a fixation target presenting means. For example, the fixation target presenting means has a fixation optical system (for example, a fixation optical system 300) that projects fixation light onto the subject's eye, and presents a fixation target to the subject's eye. For example, the fixation target may be at least one of a point image target, a landscape target, and the like.

[0010] For example, the fixation optical system may include a visible light source (e.g., light source 301) for presenting a fixation target, and a fixation target plate (e.g., fixation target plate 302). Also, for example, the fixation optical system may include a light source and a DMD (Digital Micromirror Device). Also, for example, the fixation optical system may include a display means. For example, in this case, the fixation optical system projects a fixation target displayed on a display means (for example, a display) toward the subject's eye.

[0011] For example, the fixation target presenting means may include a fixation target moving means (for example, a drive unit 307). For example, the fixation target moving means moves the position of the fixation target relative to the subject's eye. For example, the fixation target moving means may move at least one of the visible light source and the fixation target plate, the light source and the DMD, the display means, etc., in the optical axis direction by controlling the driving of a motor or the like. Also, for example, the fixation target moving means may move an optical member (for example, a lens, etc.) of the fixation optical system relative to the optical axis by controlling the driving of a motor or the like. For example, in this case, the optical member may be moved in the optical axis direction, or the optical member may be inserted or removed on the optical axis. For example, the fixation target moving means may add fog to the subject's eye by any of these configurations or a combination thereof.

[0012] <Measurement means> The eye refractive power measuring device of the present embodiment may include a measuring means. For example, the measuring means has a measuring optical system (e.g., the measuring optical system 200) including a light projecting optical system (e.g., the light projecting optical system 210) that projects a measuring light beam on the fundus of the subject's eye, and a light receiving optical system (e.g., the light receiving optical system 220) that receives a reflected light beam of the measuring light beam reflected by the fundus, and objectively measures the eye refractive power of the subject's eye. For example, the light projecting optical system may project a measuring light beam emitted from a light source (e.g., the light source 221) toward the fundus of the subject's eye. For example, the light receiving optical system may receive a reflected light beam of the measuring light beam reflected by the fundus of the subject's eye with a detector (e.g., the image sensor 226). For example, the eye refractive power of the subject's eye may be at least one of a spherical refractive power, a cylindrical refractive power, an astigmatism axis angle, and the like.

[0013] For example, the measurement optical system may be configured to project a spot-shaped measurement light beam onto the fundus of the subject's eye, and to extract the reflected light beam reflected by the fundus of the subject's eye in a ring shape, thereby detecting a ring-shaped fundus reflection image. As another example, the measurement optical system may be configured to include a light beam deflection means (e.g., a prism 214). As another example, the measurement optical system may be configured to include a Shack-Hartmann sensor. As another example, the measurement optical system may be configured to have a phase difference method of projecting a slit onto the subject's eye.

[0014] For example, the measuring means may measure the ocular refractive power of the central part of the fundus relative to the visual axis of the subject's eye by projecting a measurement light beam onto the central part of the fundus and detecting a reflected light beam from the central part of the fundus. Also, for example, the measuring means may measure the ocular refractive power of the peripheral part of the fundus relative to the visual axis of the subject's eye by projecting a measurement light beam onto the peripheral part of the fundus and detecting a reflected light beam from the peripheral part of the fundus.

[0015] For example, the visual axis of the subject's eye may be the axis of the line of sight of the subject's eye. In other words, it may be an axis passing through the fovea at the fundus of the subject's eye. Also, for example, the center of the fundus relative to the visual axis of the subject's eye may be the fovea of ​​the subject's eye. Also, for example, the peripheral part of the fundus relative to the visual axis of the subject's eye may be the peripheral part of the fovea of ​​the subject's eye. As an example, the peripheral part of the fovea of ​​the subject's eye may be the macular part of the subject's eye. Also, for example, the peripheral part of the fovea of ​​the subject's eye may be a region further outside than the macular part of the subject's eye. Of course, the peripheral part of the fovea of ​​the subject's eye may include both the macular part of the subject's eye and a region further outside than the macular part of the subject's eye.

[0016] For example, when the tilting means described later includes an optical member for expanding the projection magnification of the fixation optical system, the measuring means may acquire the ocular refractive power measured in a state where the visual angle of the fixation target is widened by the optical member as the ocular refractive power of the peripheral part of the fundus of the test eye. That is, for example, the measuring means may acquire the ocular refractive power measured in a state where the optical member is moved relative to the optical path of the fixation optical system as the ocular refractive power of the peripheral part of the fundus of the test eye. Also, for example, the measuring means may acquire the ocular refractive power measured in a state where an attachment is attached to the ocular refractive power measuring device as the ocular refractive power of the peripheral part of the fundus of the test eye.

[0017] For example, the measuring means may switch between a first mode for measuring the ocular refractive power of the fundus center portion relative to the visual axis of the subject's eye and a second mode for measuring the ocular refractive power of the fundus peripheral portion relative to the visual axis of the subject's eye based on a detection signal from a detecting means described later. For example, the first mode may be a mode for measuring the ocular refractive power of the fundus center portion of the subject's eye. As an example, in this case, the fixation optical system may be set to a predetermined projection magnification, and the fixation target may be projected at a normal visual angle. Also, in this case, the objective measurement may be performed in a state in which the visual axis of the subject's eye is not tilted with respect to the measurement optical axis of the measurement optical system. For example, the second mode may be a mode for measuring the ocular refractive power of the fundus peripheral portion of the subject's eye. As an example, in this case, the fixation optical system may be set to a projection magnification larger than a predetermined projection magnification, and the fixation target may be projected at a wider angle than a normal visual angle. Also, in this case, the objective measurement may be performed in a state in which the visual axis of the subject's eye is tilted with respect to the measurement optical axis of the measurement optical system. For example, this allows the modes to be switched in response to the attachment being attached or detached, and the ocular refractive power of the central part and peripheral part of the fundus of the subject eye can be smoothly measured.

[0018] For example, the measuring means may measure the ocular refractive power of the peripheral part of the fundus based on the acquisition result of the line-of-sight information acquiring means described later. For example, by acquiring line-of-sight information on the line of sight of the subject eye, it is possible to easily determine whether the visual axis of the subject eye is inclined with respect to the measurement optical axis. As an example, it is possible to easily determine the degree to which the visual axis of the subject eye is inclined with respect to the measurement optical axis based on the amount of deviation of the line of sight between when the line of sight of the subject eye is at the center of the fixation target and when the line of sight of the subject eye is at the periphery of the fixation target. Therefore, it is possible to project a measurement light beam onto the peripheral part of the fundus of the subject eye and acquire a reflected light beam from the peripheral part of the fundus, and to accurately measure the ocular refractive power of the peripheral part of the fundus.

[0019] <Tilt means> The eye refractive power measuring device of this embodiment may include a tilting means. For example, the tilting means aligns the peripheral part of the fundus of the test eye on the measurement optical axis by tilting the visual axis of the test eye with respect to the measurement optical axis of the measurement optical system. In other words, for example, the tilting means aligns the peripheral part of the fundus of the test eye on the measurement optical axis by making the visual axis of the test eye off the axis of the measurement optical system. As an example, the visual axis of the test eye may be moved with respect to the measurement optical axis of the measurement optical system to align the peripheral part of the fundus of the test eye on the measurement optical axis.

[0020] For example, the tilt angle at which the tilting means tilts the visual axis of the test eye with respect to the measurement optical axis of the measurement optical system may be a tilt angle set to align the measurement optical axis with respect to a region peripheral to the fovea of ​​the test eye. As an example, the region peripheral to the fovea of ​​the test eye may be at least one of a peripheral region in the macula of the test eye and a region further outside the macula of the test eye.

[0021] For example, the tilting means may increase the projection magnification of the fixation optical system to widen the visual angle of the fixation target. For example, the tilting means may include an optical member for increasing the projection magnification of the fixation optical system, and the visual angle of the fixation target may be widened by the optical member. For example, the optical member may be composed of at least one optical member. For example, the optical member may be one lens or multiple lenses. For example, the optical member may include a member other than the lens (for example, a mirror, etc.) in addition to the lens. Also, for example, the optical member may be any optical member included in the fixation optical system, or may be an optical member provided separately from the optical member included in the fixation optical system. For example, by widening the visual angle of the fixation target using such an optical member, when the subject directs his / her gaze to the periphery of the fixation target, the fixation direction of the subject's eye is greatly moved. Therefore, the visual axis of the subject's eye can be greatly inclined with respect to the measurement optical axis of the measurement optical system, and the measurement light beam can be easily projected onto the peripheral portion of the fundus of the subject's eye.

[0022] For example, the tilting means may control a driving means for driving the optical member, and move the optical member relative to the optical path of the fixation optical system to widen the visual angle of the fixation target. For example, the tilting means may be configured to move the optical member in the optical axis direction of the optical path by controlling the driving means. Also, for example, the tilting means may be configured to insert and remove the optical member in the optical path by controlling the driving means. As an example, in this case, the tilting means may be at least one of a configuration for inserting the optical member into the optical path, a configuration for removing the optical member from the optical path, a configuration for switching between inserting and removing the optical member, and the like. Of course, for example, the tilting means may be configured to combine a configuration for moving the optical member in the optical axis direction of the optical path and a configuration for inserting and removing the optical member in the optical path. For example, by moving the optical member by the tilting means in this way, the visual angle of the fixation target can be easily expanded.

[0023] For example, the tilting means may be an attachment that is detachable from the eye to be examined of the eye refraction measurement device, and the visual angle of the fixation target may be widened by attaching the attachment to the eye refraction measurement device. For example, the attachment may include an optical member for enlarging the projection magnification of the fixation optical system, and the visual angle of the fixation target may be widened by attaching the attachment. For example, this allows the fixation target to be easily enlarged in response to the attachment being attached or detached.

[0024] For example, the tilting means may widen the visual angle of the fixation target by both a configuration in which an optical element is moved relative to the optical path of the fixation optical system and a configuration in which an optical element is added by attaching an attachment.

[0025] <Attachment> The eye refraction measurement device of this embodiment is equipped with a configuration for objectively measuring the eye refraction at the center of the fundus of the test eye, and by attaching an attachment to this eye refraction measurement device, it may be possible to objectively measure the eye refraction at the peripheral part of the fundus of the test eye.

[0026] For example, the attachment may include a transformation optical system (e.g., the transformation optical system 620) for transforming a first measurement optical system that objectively measures the ocular refractive power of the central part of the fundus of the subject's eye into a second measurement optical system that objectively measures the ocular refractive power of the peripheral part of the fundus of the subject's eye. For example, by attaching the attachment, the transformation optical system is disposed in the optical path of the first measurement optical system, and the transformation optical system is used as a part of the first measurement optical system, thereby transforming it into the second measurement optical system. Also, for example, by attaching the attachment, the transformation optical system may be disposed in the optical path of the fixation optical system, and the transformation optical system is used as a part of the fixation optical system, thereby increasing the projection magnification of the fixation optical system.

[0027] For example, the transformation optical system may include at least an optical member (e.g., a wide-angle lens, etc.) for making the projection magnification of the fixation optical system wider than when the attachment is not attached. For example, such an optical member for making the projection magnification wider may be composed of one lens or multiple lenses.

[0028] <Detection Method> The eye refraction measurement device of this embodiment may include a detection means (for example, a control unit 70). For example, the detection means detects the attachment of the attachment to the eye refraction measurement device. Note that, for example, the attachment of the attachment to the eye refraction measurement device may include an electrical connection between the eye refraction measurement device and the attachment. For example, the detection means may at least detect whether or not the attachment is in contact with the eye refraction measurement device when the attachment is attached to the eye refraction measurement device. In this case, the detection means may be a contact detector (for example, a physical sensor, etc.), a non-contact detector (for example, an optical sensor, a magnetic sensor, etc.), or the like. Also, the detection means may at least detect whether or not the eye refraction measurement device and the attachment are electrically connected. In this case, the detection means may be a non-contact detector (for example, a current sensor, a voltage sensor, etc.), or the like.

[0029] <Anterior segment image acquisition means> The eye refractive power measuring device of this embodiment may include an anterior eye image acquiring means (e.g., a control unit 70). For example, the anterior eye image acquiring means acquires an anterior eye image of the subject's eye. For example, the anterior eye image may be an image including a bright spot image projected onto the subject's eye, or may be an image not including a bright spot image.

[0030] For example, the eye refractive power measurement device may be provided with an anterior eye imaging means (e.g., the observation optical system 500) for imaging the anterior eye of the subject eye. For example, the anterior eye imaging means may be provided integrally with a member (e.g., the optical system) constituting the eye refractive power measurement device. In this case, the anterior eye image acquisition means may acquire an anterior eye image as an imaging result of the anterior eye imaging means.

[0031] Of course, the anterior-segment-image acquiring means may acquire an anterior-segment image by receiving an image capturing result from another device having a function for capturing an image of the anterior segment of the subject's eye. For example, an image capturing result from a wearable device (e.g., a glasses-type wearable terminal, a head-mounted display, etc.) may be acquired as an anterior-segment image.

[0032] <Method for acquiring line of sight information> The eye refractive power measuring device of this embodiment may include a gaze information acquiring means (e.g., a control unit 70). For example, the gaze information acquiring means acquires gaze information related to the gaze of the subject's eye based on an anterior eye image. For example, the gaze information related to the gaze of the subject's eye may be information that can represent the gaze position, gaze direction, etc. of the subject's eye.

[0033] For example, the gaze information acquiring means may acquire gaze information by image analysis of the anterior eye image. As an example, the anterior eye image of the subject eye may be analyzed to detect the pupil position, and the gaze position and direction of the subject eye may be detected based on the pupil position. As another example, the anterior eye image of the subject eye may be analyzed to detect the corneal apex position, and the gaze position and direction of the subject eye may be detected based on the corneal apex position. Of course, the anterior eye image of the subject eye may be analyzed to detect the pupil position and the corneal apex position, and the gaze position and direction of the subject eye may be detected based on the pupil position and the corneal apex position. For example, the gaze information acquiring means may detect the gaze information of the subject eye by using an electrooculography method that utilizes the potential difference between the cornea and the retina of the subject eye, a corneal reflex method or a scleral reflex method that utilizes the difference in reflectance between the cornea (black eye) and the sclera (white eye) of the subject eye, or the like.

[0034] For example, the gaze information acquiring means may acquire, as the gaze information, a determination result of whether or not the subject's eye is gazing at a fixation target. In this case, the gaze information acquiring means may determine whether or not the subject's eye is gazing at a fixation target by determining whether or not the gaze position of the subject's eye overlaps at least a part of the gaze position of the fixation target (for example, the center of the fixation target or the periphery of the fixation target). In addition, in this case, the gaze information acquiring means may determine whether or not the subject's eye is gazing at a fixation target by determining whether or not the gaze position of the subject's eye overlaps at least a part of the gaze position of the fixation target continuously for a predetermined time or more.

[0035] <Example> Hereinafter, examples according to the present disclosure will be described.

[0036] 1 is an external configuration diagram of an eye refraction measurement device 1. The eye refraction measurement device 1 includes, for example, a base 2, a face support unit 3, a drive unit 4, a housing unit 10, an attachment unit 20, a display unit 75, and an operation unit 76.

[0037] 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 100 in the XYZ directions relative to the base 2. The housing unit 10 houses the first measurement unit 100 described later. The attachment unit 20 is attached to the housing unit 10. The attachment unit 20 also houses the second measurement unit 600 described later. The display unit 75 displays various information (e.g., an observation image of the subject's eye, a measurement result 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. In this embodiment, the left-right direction of the eye refractive power measurement device 1 is represented as the X direction, the up-down direction is represented as the Y direction, and the front-back direction is represented as the Z direction, as shown in FIG. 1.

[0038] Fig. 2 is an enlarged configuration diagram of the attachment unit 20. Fig. 2(a) shows a state in which the attachment unit 20 is removed from the eye refraction measurement device 1. Fig. 2(b) shows a state in which the attachment unit 20 is attached to the housing unit 10 of the eye refraction measurement device 1.

[0039] The housing 10 of the eye refraction measurement device 1 has a presentation window 11, a mounting section 12, an electrical connection section 13, a connection detection section 14, etc. The presentation window 11 is formed of a transparent member (for example, a panel) such as an acrylic resin or a glass plate.

[0040] The attachment part 20 has a presentation window 21, a mounting part 22, an electrical connection part 23, etc. The attachment part 20 also houses a second measurement part 600, which will be described later. The presentation window 21 is formed of a transparent member (for example, a panel) such as acrylic resin or a glass plate.

[0041] In this embodiment, the attachment unit 20 is detachably attached to the housing unit 10. For example, the attachment unit 12 and the attachment unit 22 are made of a ferromagnetic material, and are attached to each other by their magnetic force, and are detached by applying a force greater than the magnetic force. Of course, the attachment unit 12 and the attachment unit 22 may be attached by a structure other than a ferromagnetic material (for example, a convex portion and a concave portion fitting together). They may also be attached by a combination of a ferromagnetic material and a structure other than a ferromagnetic material.

[0042] The mounting unit 12 has a mounting detection unit 12a for detecting contact between the mounting unit 12 and the mounting unit 22. The mounting detection unit 12a may be a contact sensor (e.g., a microswitch, etc.) or a non-contact sensor (e.g., an optical sensor, a magnetic sensor, etc.). An output signal from the mounting detection unit 12a is input to the control unit 70, which will be described later. This detects that the attachment unit 20 is mounted on the housing unit 10.

[0043] In addition, in this embodiment, by attaching the attachment unit 20 to the housing unit 10, the electrical connection unit 23 of the attachment unit 20 is connected to the electrical connection unit 13 of the housing unit 10. For example, the electrical connection unit 23 is composed of a connector, and the electrical connection unit 13 is composed of a jack, and the connection between them brings the terminal and the terminal hole into contact, enabling transmission and reception of electrical signals. Note that the electrical connection unit 23 and the electrical connection unit 13 are not limited to a direct connection, and may enable transmission and reception of electrical signals through a connection via a USB cable or the like (i.e., wired communication), or may enable transmission and reception of electrical signals through a connection via Bluetooth (registered trademark) or the like (i.e., wireless communication).

[0044] The electrical connection unit 13 has a connection detection unit 14 for detecting the electrical connection between the electrical connection unit 23 and the electrical connection unit 13. The connection detection unit 14 may be a non-contact sensor (e.g., a current sensor, a voltage sensor, etc.). An output signal from the connection detection unit 14 is input to the control unit 70, which will be described later. This allows the electrical connection between the attachment unit 20 and the housing unit 10 to be detected.

[0045] <1st measurement section> First, the first measurement unit 100 of the housing unit 10 will be described. FIG. 3 is a schematic diagram of the optical system of the first measurement unit 100. For example, the first measurement unit 100 includes a measurement optical system 200, a fixation optical system 300, an index projection optical system 400, an observation optical system 500, and the like. The measurement optical system 200 objectively measures the ocular refractive power (e.g., spherical power, cylindrical power, astigmatism axis angle, and the like) of the subject's eye E. The fixation optical system 300 presents a fixation target to the subject's eye E. The index projection optical system 400 projects an alignment index for detecting the Z direction of the subject's eye E. The observation optical system 500 captures an image of the anterior segment of the subject's eye E.

[0046] <Measurement optical system> For example, the measurement optical system 200 includes a light projecting optical system 210 and a light receiving optical system 220. The light projecting optical system 210 projects a spot-shaped measurement light beam onto the fundus Ef of the subject's eye E through the center of the pupil of the subject's eye E. The light receiving optical system 220 extracts the measurement light beam reflected by the fundus Ef in a ring shape through the pupil.

[0047] For example, the light projection optical system 210 includes a light source 211, a relay lens 212, a hole mirror 213, a prism 214, a driving unit 215, an objective lens 216, and the like. The light source 211 is disposed on the optical axis N1 of the measurement optical system 200, and is in an optically conjugate positional relationship with the fundus Ef. For example, an LED (Light Emitting Diode), an SLD (Super Luminescent Diode), and the like can be used as the light source 211. The opening of the hole mirror 213 is in an optically conjugate positional relationship with the pupil. The prism 214 is disposed at a position away from the position conjugate with the pupil, and the light flux passing through the prism 214 is decentered with respect to the optical axis N1. Instead of the prism 214, a parallel flat plate may be disposed obliquely on the optical axis N1. The driving unit 215 drives the prism 214 to rotate around the optical axis N1.

[0048] The measurement light source 211 is used to project a spot-shaped measurement index onto the fundus Ef through the pupil. It is preferable that the light source 211 emits light in the infrared range that is less likely to cause the subject to feel glare. However, this is not necessarily limited to this. In this embodiment, the light source 211 is also used as an illumination light source for taking a retroillumination image of the subject's eye E. That is, the inside of the pupil of the subject's eye E is illuminated by the fundus reflection light of the light beam (illumination light) emitted from the light source 211.

[0049] For example, the light receiving optical system 220 includes an objective lens 216, a prism 214, a hole mirror 213, a relay lens 221, a total reflection mirror 222, a light receiving aperture 223, a collimator lens 224, a ring lens 225, an image sensor 226, and the like. The objective lens 216, the prism 214, and the hole mirror 213 are shared with the light projecting optical system 210. The relay lens 221 and the total reflection mirror 222 are disposed in the reflection direction of the hole mirror 213. The light receiving aperture 223, the collimator lens 224, the ring lens 225, and the image sensor 226 are disposed in the reflection direction of the total reflection mirror 222. The light receiving aperture 223 is in an optically conjugate positional relationship with the fundus Ef. The ring lens 225 is in an optically conjugate positional relationship with the pupil. For example, the ring lens 225 is composed of a lens portion in which a cylindrical lens is formed in a ring shape, and a light-shielding portion in which a light-shielding coating is applied to the lens portion. The image sensor 226 is in an optically conjugate positional relationship with the fundus Ef. For example, the image sensor 226 may be a CCD (Charged-Coupled Device), a CMOS (Complementary Metal-Oxide-Semiconductor), or the like. For example, an output signal from the image sensor 226 is input to the control unit 70.

[0050] A beam splitter 230 is disposed between the subject's eye E and the objective lens 216. The beam splitter 230 guides the measurement light beam from the fixation optical system 300 to the subject's eye E, and guides the reflected light beam from the anterior segment of the subject's eye E to the observation optical system 500.

[0051] In the above configuration, the measurement light beam emitted from the light source 211 passes through the relay lens 212, the hole mirror 213, the prism 214, the objective lens 216, and the beam splitter 230 to project a spot-shaped measurement light beam onto the fundus Ef. This forms a point light source image on the fundus Ef. At this time, the prism 214 rotates around the optical axis N1, and the pupil projection image (projection light beam on the pupil) of the opening of the hole mirror 213 is eccentrically rotated at high speed. The reflected light beam reflected by the measurement light beam on the fundus Ef is reflected to the hole mirror 213 via the beam splitter 230, the objective lens 216, and the prism 214. The reflected light beam is further reflected to the total reflection mirror 222 via the relay lens 221, and is focused at the position of the light receiving aperture 223. A ring-shaped image is formed on the image sensor 226 by the collimator lens 224 and the ring lens 225.

[0052] The measurement optical system 200 is not limited to the above configuration, and may be any measurement optical system having a light projecting optical system that projects a measurement light beam onto the fundus Ef 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 Ef. For example, the measurement optical system 200 may be a measurement optical system that projects a spot index onto the fundus Ef and detects the reflected light beam of the spot index on the fundus Ef using a Shack-Hartmann sensor.

[0053] <Fixation optical system> The fixation optical system 300 projects a fixation target onto the subject's eye E. For example, the fixation target is used to guide fixation when measuring the subject's eye E. Also, for example, the fixation target is used to fog the subject's eye E. For example, the fixation optical system 300 includes a light source 301, a fixation target plate 302, a light projecting lens 303, a total reflection mirror 304, a half mirror 305, an objective lens 306, a driving unit 307, and the like. The light source 301 is disposed on the optical axis N2. A fixation target is formed on the fixation target plate 302, and the fixation target is presented to the subject's eye E by being illuminated by the light source 301. The driving unit 307 can move the position of the fixation target presented to the subject's eye E by moving the positions of the light source 301 and the fixation target plate 302 in the direction of the optical axis N2. Further, the driving unit 307 can fog the subject's eye E by moving the light source 301 and the fixation target plate 302 in the direction of the optical axis N2. For example, the driving unit 307 may be a combination of an actuator (e.g., a stepping motor, etc.) and a photointerrupter that serves as a reference position. The driving unit 307 may change the presentation position of the fixation target by moving the position of the projection lens 303 relative to the fixation target plate 302. Therefore, the subject's eye E may be fogged by moving the position of the projection lens 303. The light beam from the light source 301 passes through the fixation target plate 302 and the projection lens 303 along the optical axis N2, is reflected by the total reflection mirror 304, passes through the half mirror 305 and the objective lens 306, is reflected by the beam splitter 230, and is projected onto the subject's eye along the optical axis N1.

[0054] <Indicator projection optical system> The index projection optical system 400 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 test eye E. The second index projection optical system projects an alignment index at finite distance onto the cornea of ​​the test eye E.

[0055] For example, the first target projection optical system has point light sources 401a and 401b, collimator lenses 402a and 402b, etc. For convenience, FIG. 3 shows only a part of the first target projection optical system. The point light sources 401a and 401b may be light sources that emit near-infrared light. The collimator lenses 402a and 402b convert the light beam emitted from the point light source into a parallel light beam (approximately parallel light beam). These point light sources and collimator lenses are arranged at 45 degree intervals on a concentric circle centered on the optical axis N1, and are symmetrical with respect to a vertical plane passing through the optical axis N1. As a result, an alignment target at infinity is projected onto the cornea of ​​the subject's eye E.

[0056] For example, the second index projection optical system has point light sources 403a and 403b. For convenience, only a part of the second index projection optical system is shown in FIG. 3. The point light sources 403a and 403b may be light sources that emit near-infrared light. For example, these point light sources are disposed at positions different from the point light sources of the first index projection optical system. This allows an alignment index at a finite distance to be projected onto the subject's eye E.

[0057] In this embodiment, the configuration using a point-like light source as the light source of the first target projection optical system and the second target projection optical system has been described as an example, but is not limited to this. For example, a ring-shaped light source or a line-shaped light source may be used as the light source. In addition, the second target projection optical system can also be used as an anterior segment illumination for illuminating the anterior segment of the subject's eye E, an index for measuring the corneal shape of the subject's eye E, etc.

[0058] <Observation optical system> For example, the observation optical system 500 includes an objective lens 306, a half mirror 305, an imaging lens 501, an imaging element 502, and the like. The objective lens 306 and the half mirror 305 are shared with the fixation optical system 300. The imaging lens 501 and the imaging element 502 are arranged in the reflection direction of the half mirror 305. The imaging element 502 is in an optically conjugate positional relationship with the anterior segment of the subject's eye E. The imaging element 502 captures a front image of the anterior segment of the subject's eye E. A transillumination image, which is a type of anterior segment image, is also captured by the imaging element 502. For example, the output from the imaging element 502 is input to the control unit 70 and the display unit 75. The observation optical system 500 also serves as an optical system for detecting an alignment index image formed on the cornea of ​​the subject's eye E by the index projection optical system 400, and the control unit 70 detects the position of the alignment index image.

[0059] <Second measurement section> Next, the second measurement unit 600 of the attachment unit 20 will be described. Fig. 4 is a schematic diagram of the optical system of the second measurement unit 600. In Fig. 4, the optical system of the first measurement unit 100 is illustrated in a simplified form together with the optical system of the second measurement unit 600. For example, the second measurement unit 600 includes an index projection optical system 610, a transformation optical system 620, and the like.

[0060] <Indicator projection optical system> The index projection optical system 610 includes a third index projection optical system and a fourth index projection optical system. The third index projection optical system projects an alignment index at infinity onto the cornea of ​​the subject's eye E. The fourth index projection optical system projects an alignment index at finite distance onto the cornea of ​​the subject's eye E. For example, in this embodiment, when the attachment unit 20 is attached, the index projection optical system 400 (the first index projection optical system and the second index projection optical system) of the first measurement unit 100 is blocked. Therefore, when the attachment unit 20 is attached, the index projection optical system 610 of the second measurement unit 600 is used for projection of the alignment index and for illumination of the anterior eye. Note that the index projection optical system 610 has the same configuration as the index projection optical system 400, and therefore a detailed description thereof will be omitted.

[0061] <Transformation optical system> The transformation optical system 620 includes a relay lens 621, an objective lens 622, and the like. For example, the relay lens 621 is conjugate with the pupil of the subject's eye E. For example, the relay lens 621 is conjugate with the pupil of the subject's eye E in a first mode (i.e., when the attachment unit 20 is not attached), which will be described later. In addition, for example, the relay lens 621 and the objective lens 622 are disposed on the optical axis N1.

[0062] In this embodiment, the optical systems of the first measurement unit 100 and the second measurement unit 600 can be integrated by attaching the attachment unit 20 to the housing unit 10. That is, when the attachment unit 20 is attached, the transformation optical system 620 is shared by the measurement optical system 200, the fixation optical system 300, and the observation optical system 500 of the first measurement unit 100. For example, this changes each optical system to a predetermined magnification (2x, as an example).

[0063] For example, a relay lens 621 and an objective lens 622 are added to the measurement optical system 200. Therefore, for example, a measurement light beam from the light source 211 of the measurement optical system 200 passes through the relay lens 621 and the objective lens 622 and is projected onto the subject's eye E. In addition, for example, a reflected light beam of the measurement light beam by the subject's eye E passes through the relay lens 621 and the objective lens 622 again and is imaged by the image sensor 226. For example, the image sensor 226 images a ring image magnified at a predetermined magnification.

[0064] Also, for example, a relay lens 621 and an objective lens 622 are added to the fixation optical system 300. Therefore, for example, a fixation light beam from the light source 301 of the fixation optical system 300 passes through each optical member along the optical axis N2, is reflected by the beam splitter 230, passes through the relay lens 621 and the objective lens 622 along the optical axis N1, and is then projected onto the subject's eye. As a result, the fixation target plate 302 is visually recognized in a state in which it is magnified by a predetermined magnification to the subject's eye. In other words, the visual angle of the fixation target 120 projected onto the subject's eye is widened.

[0065] Further, for example, a relay lens 621 and an objective lens 622 are added to the observation optical system 500. Therefore, for example, a reflected light beam of an anterior-eye segment illumination by the target projection optical system 610 passes through the relay lens 621 and the objective lens 622 along the optical axis N1, is reflected by the beam splitter 230 and the half mirror 305, and is imaged by the image sensor 502. For example, the image sensor 502 captures an anterior-eye segment image enlarged at a predetermined magnification.

[0066] <Relationship between the visual axis of the test eye and the measurement optical axis> FIG. 5 is a diagram showing the relationship between the visual axis of the subject's eye E and the measurement optical axis. FIG. 5(a) is a diagram showing a case where the center part of the fundus of the subject's eye E is measured when the attachment part 20 is not attached. FIG. 5(b) is a diagram showing a case where the peripheral part of the fundus of the subject's eye E is measured when the attachment part 20 is not attached. FIG. 5(c) is a diagram showing a case where the peripheral part of the fundus of the subject's eye E is measured when the attachment part 20 is attached. Here, the fixation optical system 300 is simplified, and the optical path from the subject's eye E to the fixation target plate 302 is a straight line. In addition, the lenses of the fixation optical system 300 (projection lens 303 and objective lens 306) are omitted to one lens 310. The optical axis of the fixation optical system 300 and the optical axis of the measurement optical system 200 are coaxial.

[0067] First, a case where the ocular refractive power of the subject's eye E is measured without the attachment unit 20 attached will be described. For example, as shown in Fig. 5(a) and Fig. 5(b), the fixation light beam from the fixation target plate 302 passes through the lens 310 and is imaged on the fundus, so that the subject's eye E can recognize the fixation target 120 of the fixation target plate 302. In this case, for example, as shown in Fig. 5(a), the subject's eye E fixates the center of the fixation target 120 (a balloon in this embodiment), so that the visual axis V1 of the subject's eye E becomes coaxial with the optical axis N1 and the optical axis N2 of the measurement optical system 200. For example, in this state, the measurement light beam from the light source 211 is projected onto the fundus center Efc, so that the ocular refractive power of the fundus center Efc can be measured. 5(b), for example, when the subject's eye E fixates on the periphery of the fixation target 120 (in this embodiment, the upper part 130 of the balloon), the visual axis V1 of the subject's eye E is tilted with respect to the optical axis N1 of the measurement optical system 200. In other words, the visual axis V1 of the subject's eye E is disposed off-axis with respect to the optical axis N1 of the measurement optical system 200. For example, in this state, the measurement light beam from the light source 211 is projected onto the peripheral part Efp of the fundus, so that the ocular refractive power of the peripheral part Efp of the fundus can be measured.

[0068] Next, a case where the ocular refractive power of the subject's eye E is measured with the attachment unit 20 attached will be described. For example, in FIG. 5(b), the visual axis V1 of the subject's eye E can be tilted with respect to the optical axis N1, but since the visual angle of the fixation target 120 (in other words, the projection size of the fixation target 120) depends on the magnification of the fixation optical system 300, it is difficult to increase the tilt angle θ° of the visual axis V1 with respect to the optical axis N1. For this reason, the ocular refractive power of the peripheral part Efp of the fundus is measured in a narrow range based on the central part Efc of the fundus of the subject's eye. Therefore, in this embodiment, as shown in FIG. 5(c), the magnification of the fixation optical system 300 is enlarged using the transformation optical system 620, and the visual angle of the fixation target 120 is made wide-angle by a predetermined magnification. This allows the ocular refractive power of the peripheral part Efp of the fundus to be measured in a wide range based on the central part Efc of the fundus of the subject's eye.

[0069] For example, in the state of FIG. 5(c), the fixation optical system 300 is enlarged (wide-angled) by a predetermined magnification, so that the test eye E recognizes a fixation target 120 larger than the actual fixation target 120. For this reason, for example, as in FIG. 5(b), even if the test eye E fixates the periphery of the fixation target 120, the visual axis V1 of the test eye E can be greatly inclined with respect to the optical axis N1 of the measurement optical system 200. That is, the inclination angle θ° can be made large (θ2°>θ1°). For example, in this state, the eye refractive power of the fundus peripheral part Efp can be measured in a wide range based on the fundus center part Efc of the test eye.

[0070] In this embodiment, in the state of Fig. 5(c), the inclination angle θ° of the visual axis V1 with respect to the optical axis N1 may be set to 10° to 20°. Of course, the inclination angle θ° may be less than 10° or greater than 20°.

[0071] <Control Unit> For example, the control unit 70 includes a CPU (processor) 71, a storage unit (hereinafter, memory) 72, and the like (see FIG. 3). The CPU 71 controls the eye refractive power measurement device 1. The memory 72 is a non-transient storage medium that can retain stored contents even when the power supply is cut off. For example, a hard disk drive, a flash ROM, a removable USB memory, and the like may be used as the memory 72. In this embodiment, various programs executed by the CPU 71 (for example, a program for performing measurement of eye refractive power, etc.) are stored in the memory 72.

[0072] The control unit 70 is electrically connected to the driving unit 4, the attachment detection unit 12a, the connection detection unit 14, the display unit 75 (operation unit 76), etc. In addition, the control unit 70 is electrically connected to the light sources, the image pickup elements, the driving units, etc., provided in the measurement unit 100.

[0073] <Control action> The control operation of the eye refraction measurement device 1 having the above-mentioned configuration will be described. In the eye refraction measurement device 1 of this embodiment, an objective measurement is performed to measure the eye refraction of the subject's eye E. For example, in the objective measurement, at least one of the eye refraction of the fundus center relative to the visual axis of the subject's eye E and the eye refraction of the fundus peripheral part relative to the visual axis of the subject's eye E may be measured. In addition, in the eye refraction measurement device 1 of this embodiment, whether the measurement result of the objective measurement is stored as the eye refraction of the fundus center part or the eye refraction of the fundus peripheral part is changed according to switching between a first measurement mode and a second measurement mode described later.

[0074] <Measurement of the central part of the fundus relative to the visual axis of the test eye> First, the measurement of the ocular refractive power of the fundus central portion relative to the visual axis of the subject's eye E will be described. In this embodiment, the ocular refractive power of the fundus peripheral portion relative to the visual axis of the subject's eye E is measured when the attachment unit 20 is not attached. For example, when the control unit 70 detects that the attachment unit 20 is not attached based on the detection result of the attachment detection unit 12a, it sets the first measurement mode and executes control according to the first measurement mode. For example, the first measurement mode is a mode for causing the subject's eye E to focus its fixation on the center of the fixation target and measuring the ocular refractive power of the fundus central portion relative to the visual axis of the subject's eye E.

[0075] First, the first measurement unit 100 is aligned with respect to the subject's eye. For example, the examiner operates the operation unit 76 to select a switch for aligning the measurement unit with respect to the subject's eye. For example, the control unit 70 turns on a point light source provided in the index projection optical system 400 under the setting of the first measurement mode based on an input signal from the operation unit 76. This projects an alignment index image onto the cornea of ​​the subject's eye E. For example, the examiner fixes the subject's face on the face support unit 3 and instructs the subject to observe the center (a balloon in this embodiment) of the fixation target 120 projected by the fixation optical system 300. Alignment index images at infinity and finite distances are projected onto the anterior segment of the subject's eye E. For example, the anterior segment of the subject's eye E is detected by the image sensor 502 provided in the observation optical system 500, and an anterior segment image is displayed on the display unit 75. For example, the control unit 70 detects the amount of misalignment of the measurement unit 100 with respect to the subject's eye E based on the positional relationship of the alignment index detected from the anterior eye image. For example, the control unit 70 controls the drive unit 4 based on the detected amount of misalignment, and drives the first measurement unit 100 three-dimensionally to perform alignment with the subject's eye E. Of course, the examiner may operate the operation unit 76 to perform manual alignment.

[0076] When the alignment of the first measurement unit 100 with respect to the subject's eye is completed, the examiner performs objective measurement of the ocular refractive power of the fundus center with respect to the visual axis of the subject's eye E. For example, the examiner instructs the subject to observe the center of the fixation target 120. For example, in this state, the visual axis V1 of the subject's eye E coincides (almost coincides) with the optical axis N1 of the measurement optical system 200, and the fundus center Efc is located on the optical axis N1. Also, for example, the examiner operates the operation unit 76 to select a switch for starting the objective measurement. For example, the control unit 70 starts the measurement based on an input signal from the operation unit 76.

[0077] For example, in the objective measurement, a preliminary measurement may be performed first, and then a main measurement may be performed. In the preliminary measurement of the subject's eye E, the eye refractive power is measured with the fixation target positioned at a predetermined presentation distance. For example, the control unit 70 causes the light source 211 of the projection optical system 210 to irradiate the subject's eye E with a measurement light beam, and performs image analysis on a ring image captured by the image sensor 226 of the light receiving optical system 220. For example, the control unit 70 thins the ring image to obtain the eye refractive power in each meridian direction, and performs a predetermined process on the eye refractive power to obtain at least a spherical power (a spherical power in the preliminary measurement).

[0078] Next, fogging is added to the subject's eye E. For example, the control unit 70 places the fixation target plate 302 at the fogging start position where the subject's eye E is focused, according to the spherical power of the preliminary measurement of the subject's eye E. The subject's eye E can clearly observe the fixation target. Thereafter, the control unit 70 moves the fixation target from the fogging start position. The subject's eye E is no longer focused on the fixation target, and fogging is added. This releases the accommodation of the subject's eye E, and the eye refractive power approaches the true value.

[0079] In this measurement, the eye refractive power is measured with the subject's eye E being clouded. For example, the control unit 70 causes the image sensor 226 to continuously capture ring images at predetermined timings. Also, for example, the control unit 70 adds the ring images to reduce noise light, and obtains the eye refractive power of the subject's eye E in the same manner as in the preliminary measurement. Furthermore, for example, since the attachment unit 20 is not attached and the first measurement mode is set, the control unit 70 stores the eye refractive power obtained in this measurement in the memory 72 as the eye refractive power of the center of the fundus relative to the visual axis of the subject's eye E.

[0080] <Measurement of the peripheral part of the fundus relative to the visual axis of the examined eye> Next, the measurement of the ocular refractive power of the peripheral part of the fundus relative to the visual axis of the subject's eye E will be described. In this embodiment, the attachment part 20 is attached to the housing part 10 of the eye refractive power measuring device 1, thereby measuring the ocular refractive power of the peripheral part of the fundus relative to the visual axis of the subject's eye E. More specifically, for example, a fixation target presented to the subject's eye E is enlarged, and the fixation of the subject's eye E is moved to the periphery of the enlarged fixation target. For example, in this state, the direction of the visual axis V1 is changed relative to the optical axis N1, so that the ocular refractive power of the peripheral part of the fundus relative to the visual axis V1 of the subject's eye E can be measured.

[0081] For example, the examiner attaches the attachment unit 20 to the housing unit 10 of the eye refractive power measuring device 1. For example, when the control unit 70 detects the attachment unit 20 being attached based on the detection result of the attachment detection unit 12a, the control unit 70 changes the setting from the first measurement mode to the second measurement mode and executes control according to the second measurement mode. For example, the second measurement mode is a mode for measuring the eye refractive power of the peripheral part of the fundus relative to the visual axis of the eye E to be examined by directing the fixation of the eye E to the periphery of an enlarged fixation target.

[0082] First, the first measurement unit 100 and the second measurement unit 600 are aligned with respect to the subject's eye. For example, the examiner operates the operation unit 76 and selects a switch for aligning the measurement unit with respect to the subject's eye. For example, the control unit 70 turns on a point light source provided in the target projection optical system 610 under the setting of the second measurement mode based on an input signal of the operation unit 76. Also, for example, the control unit 70 detects the amount of deviation in the alignment of the measurement unit based on the anterior eye image of the subject's eye E, and controls the drive unit 4 based on the amount of deviation in the alignment. Note that, for example, the anterior eye image of the subject's eye E is enlarged at a predetermined magnification by the transformation optical system 620, and further captured in a state in which it is inverted vertically and horizontally. For this reason, the allowable range of the deviation in the alignment may be changed between the first measurement mode and the second measurement mode. Also, the anterior eye image may be corrected so as to be inverted vertically and horizontally in the second measurement mode compared to the first measurement mode.

[0083] For example, when the positioning (alignment) of the measurement unit with respect to the subject's eye is completed, the examiner performs objective measurement of the ocular refractive power of the peripheral part of the fundus with respect to the visual axis of the subject's eye E. For example, the examiner instructs the subject to observe the periphery of the fixation target 120 (the upper part 130 of the balloon). Also, for example, the examiner observes an image of the anterior part of the subject's eye E, and confirms that the fixation direction of the subject's eye E has moved by the subject's eye E gazing at the upper part 130 of the balloon. For example, in this embodiment, when the line of sight of the subject's eye E is directed to the upper part 130 of the balloon, the visual axis V1 of the subject's eye E is inclined by approximately 10° with respect to the optical axis N1 of the measurement optical system 200. For example, this causes the peripheral part of the fundus Efp of the subject's eye to be positioned on the optical axis N1. Also, for example, the examiner operates the operation unit 76 and selects a switch for starting the objective measurement. For example, the control unit 70 starts the measurement based on an input signal of the operation unit 76.

[0084] For example, the control unit 70 performs a preliminary measurement and a main measurement of the subject's eye in order. The preliminary measurement and the main measurement of the peripheral part Efp of the fundus of the subject's eye are similar to the preliminary measurement and the main measurement of the central part Efc of the fundus described above, and therefore will not be described here. For example, in the preliminary measurement and the main measurement of the subject's eye, the ring image is magnified at a predetermined magnification by the conversion optical system 620 and is captured by the image sensor 22 in a state in which it is inverted vertically and horizontally. Therefore, in the second measurement mode, the ocular refractive power of the subject's eye E may be acquired taking into consideration the magnification of the ring image and the direction of the ring image.

[0085] More specifically, for example, the ring image obtained in the second measurement mode may be returned to the same magnification as the ring image obtained in the first measurement mode, and further corrected so as to invert the ring image vertically and horizontally, and the corrected ring image may be analyzed to obtain the ocular refractive power. Alternatively, for example, the ocular refractive power obtained from the ring image obtained in the second measurement mode may be corrected using a table or an arithmetic expression based on an experiment or a simulation to obtain the corrected ocular refractive power. For example, since the attachment unit 20 is attached and the second measurement mode is set, the control unit 70 stores the ocular refractive power thus obtained in the memory 72 as the ocular refractive power of the peripheral part of the fundus relative to the visual axis of the subject's eye E.

[0086] Although the ocular refractive power of the peripheral part of the fundus was measured while the subject's eye E gazed at the upper part 130 of the balloon here, the ocular refractive power of the peripheral part of the fundus may be measured sequentially while the subject's eye E gazed at the left part, right part, lower part, etc. of the balloon. In this case, the control unit 70 may store in the memory 72 the direction and inclination angle θ° of the visual axis V1 of the subject's eye E and the ocular refractive power of the peripheral part of the fundus measured while the subject's eye E gazed at each position of the balloon in association with each other.

[0087] <Measurement result output> The control unit 70 displays the eye refractive power of the fundus center Efc of the eye E to be examined in the first measurement mode and the eye refractive power of the fundus peripheral Efp of the eye E to be examined in the second measurement mode on the display unit 75 so that they can be distinguished from each other. For example, the fundus center Efc and the fundus peripheral Efp may be clearly indicated as items, and the eye refractive powers corresponding to the fundus center and the fundus peripheral may be displayed. Also, for example, the eye refractive powers corresponding to the fundus center and the fundus peripheral may be displayed together with the anterior eye image in the first measurement mode and the anterior eye image in the second measurement mode. In this case, it is possible to distinguish which eye refractive power is which from the position of the pupil reflected in the anterior eye image. Of course, the control unit 70 may display both the items of the fundus center and the fundus peripheral and the anterior eye image, or may distinguish the measurement results of the eye refractive power by displaying them differently.

[0088] In this embodiment, the control unit 70 causes the display unit 75 to display the ocular refractive power of the fundus central part Efc of the subject's eye E in the first measurement mode and the ocular refractive power of the fundus peripheral part Efp of the subject's eye E in the second measurement mode in a comparable manner. Here, an example is given of a case in which the items of the fundus central part Efc and the fundus peripheral part Efp and the anterior eye image are both displayed on the same screen, and the ocular refractive powers corresponding to the fundus central part Efc and the fundus peripheral part Efp are displayed on the same screen. Note that a configuration may be adopted in which the items of the fundus central part Efc and the fundus peripheral part Efp are switched to switch between the corresponding anterior eye images and ocular refractive powers.

[0089] 6 is an example of a display screen 700 displayed on the display unit 75. For example, the display screen 700 displays an anterior eye image 701 when the fundus central part Efc is measured, and an anterior eye image 702 when the fundus peripheral part Efp is measured. Also, for example, the display screen 700 displays a measurement result 703 when the fundus central part Efc is measured, and a measurement result 704 when the fundus peripheral part Efp is measured. For example, by checking the display screen 700, the examiner can easily grasp the ocular refractive power of the fundus central part Efc and the fundus peripheral part Efp.

[0090] For example, the control unit 70 may calculate the difference in ocular refractive power between the measurement result 703 when the fundus central part Efc of the subject's eye E is measured and the measurement result 704 when the fundus peripheral part Efp is measured, and display this on the display screen 700. Furthermore, for example, the control unit 70 may output an alert when the difference between the ocular refractive power of the fundus central part Efc of the subject's eye E and the ocular refractive power of the fundus peripheral part Efp exceeds a predetermined threshold value (for example, -1.0D, etc.) that is set in advance. For example, such an alert may be at least one of highlighting the measurement result 704 (for example, bold, underline, change of text color, etc.), displaying a message or generating a sound indicating that the difference in ocular refractive power has exceeded the threshold value, etc.

[0091] Also, at least one of the measurement results of the fundus central part Efc and the fundus peripheral part Efp of the subject's eye E may be stored in the memory 75 in association with a date, and the time-dependent changes of two or more measurement results on different dates may be output. In this case, for example, a list or graph in which the measurement results for each examination date are arranged in chronological order may be displayed on the display screen 700 so that the examiner can compare the measurement results for each examination date. This makes it easy to grasp, for example, the tendency of the measurement results over time and to easily observe the progress. Also, for example, it becomes easier to evaluate the myopia progression of the subject's eye E.

[0092] As described above, for example, the eye refractive power measuring device of this embodiment has a fixation optical system that projects fixation light onto the eye to be examined, a measurement optical system including a fixation target presenting means that presents a fixation target to the eye to be examined, a light projecting optical system that projects a measurement light beam onto the fundus of the eye to be examined, and a light receiving optical system that receives a reflected light beam of the measurement light beam reflected by the fundus of the eye to be examined, a measurement means that objectively measures the eye refractive power of the eye to be examined, and a tilting means that aligns the peripheral part of the fundus of the eye to the measurement light axis by tilting the visual axis of the eye to the measurement light axis of the measurement optical system, and the measurement means measures the eye refractive power of the peripheral part of the fundus of the eye to be examined in a state in which the visual axis of the eye to be examined is tilted by the tilting means to the measurement light axis of the measurement optical system. That is, the measurement light beam is projected onto the peripheral part of the fundus of the eye to be examined, and the reflected light beam from the peripheral part of the fundus is received, thereby measuring the eye refractive power of the peripheral part of the fundus of the eye to be examined. This makes it possible to easily measure the ocular refractive power of the peripheral part of the fundus relative to the visual axis of the subject's eye.

[0093] Also, for example, in the eye refractive power measuring device of this embodiment, the tilting means includes an optical member for enlarging the projection magnification of the fixation optical system, and the visual angle of the fixation target is widened by the optical member, and the measuring means acquires the eye refractive power measured in the state in which the visual angle of the fixation target is widened as the eye refractive power of the peripheral part of the fundus. For example, in such a configuration, the fixation target appears enlarged to the examinee. Also, when the examinee directs his / her gaze to the periphery of the enlarged fixation target, the fixation direction of the examinee's eye moves significantly, and the visual axis of the examinee's eye is tilted with respect to the measurement optical axis of the measurement optical system. Therefore, the measurement light beam of the measurement optical system is projected to the peripheral part of the fundus, and the measurement result can be easily acquired as the eye refractive power of the peripheral part of the fundus.

[0094] Also, for example, in the eye refraction measurement device of this embodiment, the tilting means has an optical member and is an attachment that can be attached to the eye side of the eye refraction measurement device, and the attachment is attached to the eye refraction measurement device to widen the visual angle of the fixation target. For example, when the optical member is moved relative to the optical path of the fixation optical system inside the eye refraction measurement device to widen the visual angle of the fixation target, it is necessary to secure a space for moving the optical member and to arrange a larger objective lens in order to set the fixation optical system to an appropriate projection magnification, which may complicate the configuration of the device or increase the size of the device. However, for example, when the attachment is attached, the visual angle of the fixation target can be easily expanded while suppressing the complexity of the configuration and the size of the device, so that the fixation direction of the test eye can be moved significantly to easily obtain the eye refraction of the peripheral part of the fundus.

[0095] Also, for example, the eye refractive power measuring device of this embodiment includes a detection means for detecting the attachment to the eye refractive power measuring device, and the measurement means switches between a first mode for measuring the eye refractive power of the center part of the fundus of the subject eye and a second mode for measuring the eye refractive power of the peripheral part of the fundus of the subject eye based on a detection signal from the detection means. This allows the examiner to switch between the modes depending on whether the attachment is attached or detached, and allows the examiner to smoothly measure the eye refractive power of the center part of the fundus of the subject eye and the eye refractive power of the peripheral part of the fundus of the subject eye.

[0096] For example, the attachment of the present embodiment is an attachment to be attached to an eye refractive power measurement device, the eye refractive power measurement device has a first measurement optical system that objectively measures the eye refractive power of the fundus center of the test eye, and the attachment has a conversion optical system for converting the first measurement optical system into a second measurement optical system that objectively measures the eye refractive power of the fundus peripheral part of the test eye. For example, since the configuration of the measurement optical system can be easily converted according to the attachment being attached or detached, the eye refractive power of the fundus center part of the test eye and the eye refractive power of the fundus peripheral part of the test eye can be smoothly obtained.

[0097] <Example of transformation> In the eye refractive power measurement device of this embodiment, the transformation optical system 620 is configured with two lenses, a relay lens 621 and an objective lens 622, as a configuration for enlarging (widening the angle) the fixation target 120, but is not limited to this. For example, the transformation optical system 620 may be configured with at least one lens. Also, for example, the transformation optical system 620 may include an optical member (such as a mirror, for example) different from the lens in addition to the lens.

[0098] In the eye refractive power measuring device of this embodiment, the attachment unit 20 is attached to increase the projection magnification of the fixation optical system 300, thereby widening the angle of the fixation target 120. However, the present invention is not limited to this. For example, the fixation target 120 may be widened by moving an optical member included in the fixation optical system 300 relative to the optical path of the fixation optical system 300.

[0099] Fig. 7 is a schematic diagram of the fixation optical system 300. Fig. 7(a) shows a case where the light source 301 and the fixation target plate 302 are moved in the optical axis direction. Fig. 7(b) shows a case where the projector lens 303 is moved in the optical axis direction. Fig. 7(c) shows a case where a lens is disposed between the projector lens 303 and the objective lens 306. Here, the fixation optical system 300 is simplified, and the optical path from the subject's eye E to the fixation target plate 302 is a straight line.

[0100] For example, as shown in FIG. 7(a), the fixation target 120 may be made wider-angle by moving the light source 301 and the fixation target plate 302 in the optical axis direction (direction away from the eye E). For example, in this case, a driving unit (for example, a driving unit 307) for moving the light source 301 and the fixation target plate 302 integrally may be provided, and the light source 301 and the fixation target plate 302 may be moved to a predetermined position by controlling the driving unit. Also, for example, as shown in FIG. 7(b), the fixation target 120 may be made wider-angle by moving the projection lens 303 in the optical axis direction (direction away from the eye E). For example, in this case, a driving unit (for example, a driving unit 320) for moving the projection lens 303 may be provided, and the projection lens 303 may be moved to a predetermined position by controlling the driving unit. 7(c), for example, a lens 330 may be inserted or removed on the optical axis between the projection lens 303 and the objective lens 306 to widen the angle of the fixation target 120. In this case, for example, a drive unit (e.g., drive unit 340) for inserting or removing the lens 330 may be provided, and the lens 330 may be inserted or removed by controlling the drive unit.

[0101] Note that the projection magnification of the fixation optical system 300 may be increased by, for example, performing at least one of the movement of the light source 301 and the fixation target plate 302, the movement of the projector lens 303, and the insertion / removal of the lens 330. Of course, the projection magnification of the fixation optical system 300 may be increased by, for example, both the attachment of the attachment unit 20 and at least one of the movement of the light source 301 and the fixation target plate 302, the movement of the projector lens 303, and the insertion / removal of the lens 330.

[0102] Furthermore, for example, in response to switching between the first measurement mode and the second measurement mode, the projection magnification of the fixation optical system 300 may be increased by changing at least one of the movement of the light source 301 and the fixation target plate 302, the movement of the projector lens 303, the insertion or removal of the lens 330, etc.

[0103] For example, in the eye refractive power measuring device of this embodiment, the tilting means for tilting the visual axis V1 of the subject's eye relative to the optical axis N1 of the measurement optical system 200 controls the driving means for driving the optical member, and moves the optical member relative to the optical path of the fixation optical system, thereby widening the visual angle of the fixation target. This makes it possible to easily enlarge the fixation target, for example, and to greatly move the fixation direction of the subject's eye.

[0104] In this embodiment, the configuration is described as an example in which the projection magnification of the fixation optical system 300 is fixed when the attachment unit 20 is attached, thereby measuring the ocular refractive power of the peripheral part Efp of the fundus at a predetermined inclination angle θ° of the visual axis V1 relative to the optical axis N1, but the present invention is not limited to this. For example, the attachment unit 20 may be provided with a zoom lens or the like, and the projection magnification of the fixation optical system 300 may be made variable, thereby changing the inclination angle θ°. As an example, the inclination angle θ° may be set to any angle between 10° and 20° by the zoom lens. In this case, since the visual angle of the fixation target relative to the subject's eye E is changed stepwise, the inclination angle θ° can be changed while the subject's eye E maintains its gaze on the periphery of the fixation target (the upper part 130 of the balloon). Of course, even in the configuration in which the light source 301, the fixation target plate 302, the projection lens 303, etc. are moved, the projection magnification of the fixation optical system 300 can be changed to change the inclination angle θ° by adjusting the amount of movement of these in the optical axis direction. In addition, by forming lens 330 using multiple lenses and using different lenses to insert and remove them on the optical axis, it is also possible to vary the projection magnification of the fixation optical system 300 and change the inclination angle θ°.

[0105] In this embodiment, the configuration in which the examiner checks the anterior eye image to determine whether the subject's eye E is gazing at the periphery of the fixation target 120 has been described as an example, but the present invention is not limited thereto. For example, it is also possible to detect whether the subject's eye E is gazing at the periphery of the fixation target 120 by acquiring line-of-sight information regarding the subject's line of sight. In addition, it is also possible to detect whether the visual axis V1 of the subject's eye E is inclined with respect to the optical axis N1, and to measure the ocular refractive power of the fundus peripheral portion Efp based on the detection result.

[0106] 8 is a diagram for explaining acquisition of the subject's line of sight information. For example, the anterior eye image 710 includes a bright spot image R that appears due to the infrared light source of the third index projection optical system and the fourth index projection optical system of the index projection optical system 610. For example, the bright spot image R may be composed of a ring index image R1 that appears due to the infrared light source of the third index projection optical system and a ring index image R2 that appears due to the infrared light source of the fourth index projection optical system.

[0107] For example, the control unit 70 performs image processing on the anterior eye image 710 captured by the imaging element 502 of the observation optical system 500 to detect the pupil and the bright spot image R. For example, the pupil may be detected using the luminance information of the anterior eye image 710, and the center of the pupil may be calculated to detect the pupil center Ep. For example, the bright spot image R may be detected using the luminance information of the anterior eye image 700, and the corneal apex K may be detected by calculating the center of either the ring index image R1 or the ring index image R2. Furthermore, the control unit 70 detects the direction of the corneal apex K relative to the pupil center Ep and the shift amount Δd, and specifies the direction of the line of sight of the subject eye E. For example, the shift amount Δd may be calculated by calculating the number of pixels between the pixel position of the pupil center Ep and the pixel position of the corneal apex K. Note that the shift amount Δd increases as the line of sight of the subject eye E moves and the eye position of the subject eye E (for example, the rotation angle with respect to the optical axis N1 based on the rotation center of the subject eye) increases. The direction of the line of sight of the subject's eye E is appropriately identified by calculating the deviation amount Δd.

[0108] For example, the control unit 70 can detect the direction of the line of sight of the subject's eye E (i.e., the direction of the visual axis V1) based on the shift amount Δd of the subject's eye E and the distance from the subject's eye E to the image sensor 502. For example, the shift amount Δd generated by the subject's eye gazing at the peripheral position of the fixation target 120 presented to the subject's eye E may be associated in advance with each peripheral position of the fixation target 120 presented to the subject's eye E. For example, when the control unit 70 detects a predetermined shift amount Δd between the pupil center Ep and the corneal apex K in the anterior eye image 701, the control unit 70 may detect whether the subject's eye E is gazing at the peripheral position of the fixation target 120. In addition, for example, the control unit 70 may detect the inclination angle θ° of the visual axis V1 with respect to the optical axis N2 by detecting such a predetermined shift amount Δd. As an example, a table or the like in which the shift amount Δd and the inclination angle θ° are associated with each other through experiments or simulations may be stored in the memory 75 in advance, and the inclination angle θ° may be referenced from the detected shift amount Δd using the table. For example, the control unit 70 may automatically start measuring the ocular refractive power of the peripheral part of the fundus relative to the visual axis of the subject's eye E based on this detection result.

[0109] For example, the eye refractive power measuring device of this embodiment may include an anterior eye image acquiring means for acquiring an anterior eye image of the eye to be examined, and a gaze information acquiring means for acquiring gaze information related to the gaze of the eye to be examined based on the anterior eye image, and the measuring means may measure the eye refractive power of the peripheral part of the fundus based on the acquisition result of the gaze information acquiring means. For example, by acquiring the gaze information related to the gaze of the eye to be examined, it is possible to easily determine the degree to which the visual axis of the eye to be examined is inclined. Therefore, the eye refractive power of the peripheral part of the fundus of the eye to be examined can be accurately measured.

[0110] In this embodiment, when measuring the ocular refractive power of the peripheral part of the fundus relative to the visual axis V1 of the subject's eye E, the subject is guided to gaze at the periphery of the fixation target 120 (the upper part 130 of the balloon), but the present invention is not limited thereto. For example, a plurality of point light sources or the like may be arranged around the fixation target plate 302, and the light source in the direction in which the visual axis V1 is to be tilted may be turned on to cause the subject's eye E to gaze at the fixation target plate 302. As an example, in this case, a plurality of point light sources may be arranged in a meridian direction based on the fixation optical axis. Note that the number of meridian directions in which the point light sources are arranged may be any number (for example, the first meridian direction, the second meridian direction, the third meridian direction, the fourth meridian direction, etc.). Also, at least one light source may be arranged in one meridian direction. As an example, three light sources may be arranged in one meridian direction so that the inclination angle θ° of the visual axis V1 of the subject's eye E is 10°, 15°, 20°, etc.

[0111] Also, for example, when measuring the ocular refractive power of the peripheral part of the fundus relative to the visual axis V1 of the subject's eye E, a display may be used instead of the fixation target plate 302, and the display on the display may be changed to cause the subject's eye E to gaze at the fixation target. For example, in this case, a focus point for the subject's eye to gaze at may be superimposed on the fixation target on the display. As an example, one focus point may be superimposed on the fixation target so that the inclination angle θ° of the visual axis V1 of the subject's eye E becomes a predetermined angle (10°, etc.). Of course, a plurality of focus points may be set in advance, and the subject may gaze at the plurality of focus points in sequence to measure the ocular refractive power of the peripheral part of the fundus at a plurality of inclination angles θ° (10°, 15°, 20°, etc.). Also, the position where one focus point is superimposed may be appropriately moved to measure the ocular refractive power of the peripheral part of the fundus at a plurality of inclination angles θ°.

[0112] For example, even when the line of sight of the subject's eye E is guided to a predetermined point light source or a focus point as described above and the subject's eye E is made to gaze at a predetermined position of the fixation target, the visual axis V1 of the subject's eye E can be set at an arbitrary inclination angle θ°, and the eye refractive power of the peripheral part of the fundus can be easily measured. In this case, the subject's eye may adjust to focus on the point light source or the focus point, which may prevent the eye refractive power of the peripheral part of the fundus from being properly measured. For this reason, for example, the control unit 70 may measure the eye refractive power of the peripheral part of the fundus while the subject's eye is gazing at the point light source or the focus point and the adjustment is released. As an example, the light source 301 and the fixation target plate 302 may be moved in the direction of the optical axis N2 to move the presenting position of the fixation target, thereby adding fog to the subject's eye and releasing the adjustment.

[0113] Moreover, such measurement results for multiple fundus peripheral parts of the subject's eye may be represented by a map or graph plotting the direction of the visual axis V1, the inclination angle θ°, and each measurement result. For example, when the subject directs his / her gaze toward the upper part 130 of the balloon, the position at which the fixation target is gazed upon is likely to differ, but by directing the gaze toward a point light source or a point of interest, the position at which the fixation target is gazed upon is likely to be kept within a certain range, so that a more accurate map or graph can be created.

[0114] In the eye refractive power measuring device of this embodiment, the index projection optical system 610 is provided in the second measurement unit 600 of the attachment unit 20, and when the attachment unit 20 is attached, the alignment index image is projected by the index projection optical system 610. However, the present invention is not limited to this. For example, depending on the configuration of the attachment unit 20, the index projection optical system 400 of the first measurement unit 100 may not be blocked. Therefore, for example, even when the attachment unit 20 is attached, the alignment index image may be projected using the index projection optical system 400. In this case, the distance between the subject's eye and the index projection optical system 400 increases by attaching the attachment unit 20, and the amount of light illuminating the subject's eye may decrease. Therefore, for example, the control unit 70 may change the amount of light of the point light source in the index projection optical system 400 when detecting the attachment unit 20 being attached and changing the setting from the first measurement mode to the second measurement mode. In this case, the position and size of the bright spot image projected onto the subject's eye may change by attaching the attachment unit 20. Therefore, the control unit 70 may change the illumination pattern of the bright spot image, etc., when detecting the attachment unit 20 and changing the setting from the first measurement mode to the second measurement mode.

[0115] In the eye refractive power measuring device of this embodiment, the objective lens 622 of the transformation optical system 620 is a convex lens, but the present invention is not limited thereto. For example, the objective lens 622 of the transformation optical system 620 may be a concave lens. For example, as described above, when the objective lens 622 is a convex lens, the imaging magnification of the ring image is changed by the transformation optical system 620, and the ring image is inverted up, down, left, and right. On the other hand, when the objective lens 622 is a concave lens, the imaging magnification of the ring image is changed by the transformation optical system 620, but the ring image is not inverted up, down, left, and right. For this reason, for example, the control unit 70 may calculate the eye refractive power by correcting the magnification of the ring image captured by the image sensor 226 in advance. Note that, for example, the anterior eye image captured by the observation optical system 500 may also be subjected to processing such as magnification correction and image inversion in accordance with the lens configuration of the transformation optical system 620. [Explanation of symbols]

[0116] 1. Eye refractive power measuring device 10 Housing 20 Attachment part 70 Control section 72 Memory section 75 Display section 76 Control section 100 1st measurement section 200 Measurement optical system 300 Fixation optical system 400 Index projection optical system 500 Observation Optical System 600 2nd measurement section 610 Index projection optical system 620 Transformation Optical System

Claims

1. An eye refractive power measuring device, a fixation target presenting means having a fixation optical system that projects fixation light onto the subject's eye and presents a fixation target to the subject's eye; a measuring means for objectively measuring the ocular refractive power of the subject's eye, the measuring means having a measuring optical system including a light projecting optical system that projects a measuring light beam onto the fundus of the subject's eye and a light receiving optical system that receives a reflected light beam of the measuring light beam reflected by the fundus; a tilting unit for tilting a visual axis of the subject's eye with respect to a measurement optical axis of the measurement optical system, thereby aligning a peripheral portion of the fundus of the subject's eye on the measurement optical axis; Equipped with The measurement means measures the ocular refractive power of the peripheral part of the fundus of the subject eye while the tilting means tilts the visual axis of the subject eye relative to the measurement optical axis of the measurement optical system.

2. 2. The eye refractive power measuring device according to claim 1, the tilting means includes an optical element for increasing the projection magnification of the fixation optical system, and widens the visual angle of the fixation target by the optical element; An eye refractive power measuring device characterized in that the measuring means acquires the eye refractive power measured with the visual angle of the fixation target widened as the eye refractive power of the peripheral part of the fundus.

3. 3. The eye refractive power measuring device according to claim 2, The tilting means controls a driving means for driving the optical element, and moves the optical element relative to the optical path of the fixation optical system, thereby widening the visual angle of the fixation target.

4. The eye refractive power measuring device according to claim 2 or 3, the tilting means is an attachment that has the optical member and is detachable from the eye to be examined of the eye refractive power measuring device, An eye refractive power measuring device, characterized in that the visual angle of the fixation target is widened by attaching the attachment to the eye refractive power measuring device.

5. 2. The eye refractive power measuring device according to claim 1, an anterior ocular segment image acquiring means for acquiring an anterior ocular segment image of the subject's eye; a line-of-sight information acquiring means for acquiring line-of-sight information regarding the line of sight of the subject's eye based on the anterior-segment image; Equipped with The eye refractive power measuring device is characterized in that the measuring means measures the eye refractive power of the peripheral part of the fundus based on the results acquired by the line-of-sight information acquiring means.

6. An attachment to be attached to an eye refractive power measuring device, The eye refractive power measuring device has a first measuring optical system that objectively measures the eye refractive power of a central part of the fundus of the subject's eye, The attachment is characterized in that it includes a conversion optical system for converting the first measurement optical system into a second measurement optical system that objectively measures the ocular refractive power of the peripheral part of the fundus of the subject's eye.

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