Eye examination device and attachment to be attached to the eye examination device

Abstract

To provide an eye examination device capable of acquiring information on an eye to be examined depending on a situation, and an attachment mounted on the eye examination device.SOLUTION: An attachment mounted on an eye examination device having a first objective optical system for objectively acquiring information on an eye to be examined includes a conversion optical system for converting the first objective optical system into a second objective optical system for objectively measuring eye refractive power of the eye to be examined by a photorefraction system. The eye examination device includes mounting means by which the attachment is mounted and connection means for electrically connecting the eye examination device and the attachment to each other. The attachment is made into a usable state by the connection using the connection means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an eye examination device and an attachment to be attached to the eye examination device. [Background technology]

[0002] As an example of information on the subject's eye, an eye examination apparatus that objectively acquires the ocular refractive power of the subject's eye is known. For example, the ocular refractive power of the subject's eye can be measured by projecting a measurement light beam onto the fundus of the subject's eye and receiving the light beam reflected from the fundus (see Patent Document 1).

[0003] The eye examination apparatus includes a stationary type such as that disclosed in the cited document 1 and a handheld type such as that disclosed in the cited document 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-187483 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-183123 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, there is a need to obtain ocular refractive power in various situations depending on the purpose and use of the examiner or subject. For example, there are situations where high accuracy is required, situations where simple measurement is required, situations where efficient measurement is required, etc. Therefore, there is a need for a measurement device that can be adapted to suit the situation.

[0006] In view of the above problems, the present disclosure has as its technical object to provide an eye examination apparatus that can acquire information on the subject's eye according to the situation, and an attachment to be attached to the eye examination apparatus. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention is characterized by having the following configuration.

[0008] The attachment according to the first aspect of the present disclosure is an attachment to be attached to an eye examination device having a first objective optical system for objectively obtaining information about the subject's eye, and is characterized by comprising a conversion optical system for converting the first objective optical system into a second objective optical system that objectively measures the ocular refractive power of the subject's eye using a photorefraction method. An eye examination device according to a second aspect of the present disclosure is an eye examination device that is fitted with the attachment of the first aspect, and is characterized in that it comprises an attachment means to which the attachment is fitted and a connection means that electrically connects the eye examination device and the attachment, and the attachment becomes usable by connecting using the connection means. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an external view of a handheld eye examination device with an attachment attached thereto. [Figure 2] FIG. 2 is an external view of the handheld eye examination device with the attachment removed. [Figure 3] FIG. 2 is a schematic diagram illustrating the configuration of a first measurement unit. [Figure 4] FIG. 3 is a schematic diagram illustrating the configuration of a second measurement unit. [Figure 5] 10 is an example of a display section in a first measurement mode. [Figure 6] 10 is an example of a display unit in a second measurement mode. [Figure 7] FIG. 1 is a diagram illustrating a photorefraction method. [Figure 8] FIG. 1 is an external view of a stationary eye examination device. [Figure 9] FIG. 2 is a schematic diagram illustrating the configuration of a measurement unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Summary> An overview of an eye examination device and its attachments according to an embodiment of the present disclosure will be described. The items classified in < > below may be used independently or in conjunction with each other. Note that "conjugate" in this embodiment is not necessarily limited to a perfect conjugate relationship, but also includes "substantially conjugate." In other words, "conjugate" in this embodiment also includes cases where the devices are positioned at positions that are shifted from a perfect conjugate position, within the range permitted in relation to the technical significance of each part.

[0011] <Eye examination device> The eye examination apparatus of this embodiment may be a handheld eye examination apparatus or a stationary eye examination apparatus. The eye examination apparatus may be equipped with at least two objective measurement devices and configured to measure the ocular refractive power of the subject's eye using different methods. By controlling at least one of the multiple objective measurement devices, the ocular refractive power of the subject's eye can be obtained in accordance with various situations.

[0012] The eye examination apparatus may include a first objective measuring means (e.g., the first measuring unit 40, the measuring unit 260) that objectively measures the ocular refractive power of the subject's eye using a method other than the photorefraction method. The first objective measuring means may include at least a first objective measuring optical system (e.g., the first measuring optical system 50) as a part of the first objective measuring means.

[0013] The eye examination apparatus may also include a second objective measuring means (e.g., a second measuring unit 90, a measuring unit 260) that objectively measures the ocular refractive power of the subject's eye by a photorefraction method. The second objective measuring means may include at least a second objective measuring optical system (e.g., a second measuring optical system 100, a second measuring optical system 300) as a part of the second objective measuring means.

[0014] The eye examination apparatus may also include a control means (for example, the control unit 130) that controls at least one of the first objective measuring means and the second objective measuring means to obtain the eye refractive power.

[0015] <First objective measurement means> For example, the first objective measuring means may measure the ocular refractive power of one of the examinee's eyes by projecting a measurement light beam onto the fundus of the eye using a method other than the photorefraction method. In this case, the first objective measuring means requires stricter (severe) alignment than the second objective measuring means, but the measurement accuracy can be improved.

[0016] For example, the first objective measurement means may be an objective measurement means that projects a measurement light beam onto the fundus of the subject's eye and receives a reflected light beam from the fundus using a first detector. In this case, the first detector may be disposed at a position conjugate with the fundus of the subject's eye.

[0017] Furthermore, for example, the first objective measuring means may be an objective measuring means that projects a pattern target as a measurement light beam onto the fundus of the subject's eye and receives a reflected light beam from the fundus using a first detector. In this case, the control means may acquire the ocular refractive power based on the reflected light beam received by the first detector. As an example, the reflected light beam may be extracted as a ring image and the ocular refractive power may be acquired based on the ring image. As another example, the reflected light beam may be detected by a Shack-Hartmann sensor to acquire the ocular refractive power. In other words, the first objective measuring means may be an imaging-type objective measuring means. In other words, the first objective measuring means may be an objective measuring means that measures the ocular refractive power using a refractometer method.

[0018] Furthermore, for example, the first objective measurement means may be an objective measurement means that projects measurement light beams from at least two light sources onto the fundus of the subject's eye and receives a reflected light beam from the fundus using a first detector. In this case, a spot light may be projected onto the subject's eye. In this case, the control means may acquire the ocular refractive power based on the coincidence state of the two reflected light beams received by the first detector. In other words, the first objective measurement means may be a coincidence-type objective measurement means.

[0019] Furthermore, for example, the first objective measurement means may be an objective measurement means that scans a measurement light beam over the fundus of the subject's eye and receives a reflected light beam from the fundus using a first detector. In this case, a slit light may be projected onto the subject's eye. In this case, the control means may acquire the ocular refractive power based on a phase difference signal from the first detector. In other words, the first objective measurement means may be an objective measurement means that measures the ocular refractive power using a phase difference method.

[0020] <Second objective measurement means> For example, the second objective measuring means may measure the ocular refractive power of both eyes by projecting a measurement beam onto the fundus of the eye using a photorefraction method. In this case, although the measurement accuracy of the second objective measuring means is lower than that of the first objective measuring means, it is possible to obtain measurement results simply and efficiently.

[0021] For example, the second objective measurement means may be an objective measurement means that projects a measurement light beam onto the fundus of the subject's eye and receives the reflected light beam from the fundus with a second detector. In this case, the second detector may be disposed at a pupil conjugate position of the subject's eye.

[0022] Furthermore, for example, the second objective measurement means may be an objective measurement means that projects a non-patterned target as a measurement light beam onto the fundus of the subject's eye and receives a reflected light beam of the measurement light beam reflected by the fundus with a second detector. In this case, the control means may acquire the ocular refractive power based on the state of the light beam at the pupil of the subject's eye received by the second detector. As an example, the ocular refractive power may be acquired based on the ratio of the light beam at the pupil. In other words, the second objective measurement means may be an objective measurement means that measures the ocular refractive power using retinoscopy (skiascopy or retinoscopy).

[0023] The second objective measuring means will be described in detail. The second objective measuring means may have a light projecting optical system (e.g., light projecting optical system 110, light projecting optical system 310) and a light receiving optical system (e.g., light receiving optical system 120, light receiving optical system 320). For example, the light projecting optical system and the light receiving optical system may be configured with different optical members, or at least some of the optical members may be shared.

[0024] The light projection optical system may include at least a measurement light source. For example, the light projection optical system may include multiple measurement light sources (e.g., measurement light source 111, measurement light source 311) arranged in meridian directions (radial directions) based on the optical axis center, and irradiate the fundus of the subject's eye with measurement light beams emitted from the multiple measurement light sources. The multiple measurement light sources may be independently controlled. For example, the on / off and light intensity adjustment of each measurement light source may be independently controlled. The multiple measurement light sources may also be arranged separately from each other in at least three meridian directions based on the optical axis center. For example, by arranging the measurement light sources in at least three meridian directions, ocular refractive power including spherical power, cylindrical power, astigmatic axis angle, etc. can be measured. The measurement light sources may be arranged in any number of meridian directions (e.g., first meridian direction, second meridian direction, third meridian direction, fourth meridian direction, etc.). At least one measurement light source may be arranged in each meridian direction.

[0025] For example, the light projection optical system may include an objective optical system that irradiates measurement light beams emitted from a plurality of measurement light sources onto the fundus of the subject's eye, and may have one or more optical members for projecting the measurement light beams toward the subject's eye.

[0026] The light receiving optical system may have at least a detector. For example, the light receiving optical system receives the measurement light beam reflected by the fundus of the subject's eye with a detector (e.g., the image sensor 122 or the image sensor 323).

[0027] For example, the light receiving optical system may include an objective optical system (e.g., wide-angle lens 121, wide-angle lens 321). The objective optical system guides the reflected light beam of the measurement light beam reflected by the fundus of the subject's eye to a detector. The objective optical system may have one or more optical members for guiding the reflected light beam by the fundus of the subject's eye to the detector.

[0028] In this embodiment, the first objective measurement means measures one eye of the subject using a method other than the photorefraction method, and the second objective measurement means measures both eyes of the subject using a method other than the photorefraction method. Therefore, the objective measurement means differ in at least one of measurement accuracy and ease of measurement (e.g., ease of alignment). For example, the first objective measurement means has higher measurement accuracy but lower measurement ease (in other words, more difficult) than the second objective measurement means. Also, the second objective measurement means has lower measurement accuracy but higher measurement ease (in other words, easier) than the first measurement means. Therefore, the two measurement methods can be used appropriately depending on the situation.

[0029] In addition, in this embodiment, by using the first objective measurement means as a fundus conjugate system and the second objective measurement means as a pupil conjugate system, it is possible to easily switch between the two measurement methods and select the measurement accuracy and ease of measurement that correspond to the eye to be examined.

[0030] In addition, in this embodiment, the first objective measuring means obtains the ocular refractive power based on at least one of the ring image, the coincidence state of the reflected light beams, and the phase difference signal, and therefore can obtain information for many meridian directions. As a result, the ocular refractive power can be measured more accurately than with the second objective measuring means.

[0031] <Combined use of objective measurement methods> The first objective measuring means and the second objective measuring means may be provided independently of each other, or at least some of the optical members in the optical systems constituting the respective objective measuring means may be shared.

[0032] The first objective measurement means may include a light projection optical system that projects light toward the anterior segment of the subject's eye. For example, the light projection optical system may be an illumination optical system for illuminating the anterior segment. Furthermore, for example, the light projection optical system may be an index projection optical system (e.g., index projection optical system 70) that projects an index light beam for alignment onto the subject's eye. Furthermore, for example, the light projection optical system may be an index projection optical system that projects an index light beam for corneal shape measurement onto the subject's eye. Note that the light projection optical system may be configured to have at least a light source.

[0033] The light source of the light projection optical system provided in the first objective measurement means may also serve as the measurement light source of the second objective measurement means. That is, the light source for illuminating the anterior segment of the eye to be examined or the light source for projecting an index light beam onto the anterior segment of the eye to be examined may also serve as the measurement light source for projecting a measurement light beam onto the fundus in photorefraction measurement of the eye to be examined. This makes it possible to obtain ocular refractive powers based on different measurement methods with a simple configuration, without providing dedicated light sources for the first objective measurement means and the second objective measurement means.

[0034] The second objective measuring means can acquire the ocular refractive power based on the movement of light when a plurality of measurement light sources are arranged in the meridian direction based on the center of the optical axis of the light projecting optical system and each measurement light source is turned on in turn. Therefore, it is preferable to use a light source that emits a point-like or line-like light beam as the light source of the light projecting optical system in the first objective measuring means so that the meridian direction can be identified.

[0035] The first objective measurement means may include an anterior-segment observation optical system that captures an image of the anterior segment of the subject's eye. For example, the anterior-segment observation optical system may be any optical system that can capture an image of the anterior segment. Note that the anterior-segment observation optical system may be configured to include at least a detector.

[0036] The detector of the anterior ocular segment observation optical system provided in the first objective measurement means may also serve as the detector of the second objective measurement means. That is, a detector for photographing the anterior ocular segment of the subject's eye may also be used as a detector (second detector) for receiving a measurement light beam reflected by the fundus in photorefraction measurement of the subject's eye. This makes it possible to obtain ocular refractive powers based on different measurement methods with a simple configuration, without providing dedicated detectors for the first objective measurement means and the second objective measurement means.

[0037] The eye examination apparatus may be configured so that only the light source is shared between the first objective measuring means and the second objective measuring means, or so that only the detector is shared between them. Of course, it may also be configured so that both the light source and the detector are shared between them.

[0038] <First alignment means> The eye examination apparatus may include a first alignment means for photographing the subject's eye and adjusting the positional relationship between the subject's eye and the first objective measurement means. For example, the first alignment means may be used in a measurement method other than the photorefraction method. Furthermore, for example, the first alignment means may adjust the positional relationship between the subject's eye and the first objective measurement means by photographing the anterior segment of the subject's eye over a narrow range. In this case, the working distance from the subject's eye to the first objective measurement means may be set shorter than the working distance from the subject's eye to the second objective measurement means.

[0039] The first alignment means may have at least a light source and a detector. For example, the first alignment means may have an index projection optical system (e.g., index projection optical system 70). In this case, an index light beam may be projected onto the cornea of ​​the subject's eye, and an alignment index image may be detected based on the index light beam reflected by the cornea. Note that an anterior-segment observation optical system (e.g., anterior-segment observation optical system 80) for photographing the anterior segment of the subject's eye may also perform the function of detecting the alignment index image. In other words, the first alignment means may be an alignment optical system including an index projection optical system and an anterior-segment observation optical system.

[0040] For example, the first alignment means may use an alignment target image to finely adjust the relative position of the first objective measurement means with respect to the subject's eye. In other words, the first alignment means may be used to perform more precise (severe) alignment than the second alignment means.

[0041] <Second alignment means> The eye examination apparatus may include a second alignment means for adjusting the positional relationship between the eye and the second objective measurement means by photographing the eye at a wider angle than the first alignment means. For example, the first alignment means may be used in a photorefraction measurement. Furthermore, for example, the second alignment means may adjust the positional relationship between the eye and the second objective measurement means by photographing the anterior segment of the eye over a wider range. In this case, the working distance from the eye to the second objective measurement means may be set longer than the working distance from the eye to the first objective measurement means.

[0042] For example, the second alignment means may include at least a detector. For example, the second alignment means may be an anterior-segment observation optical system (e.g., an anterior-segment observation optical system 80, a light-receiving optical system 320) for capturing an image of the anterior segment of the subject's eye. For example, the second alignment means may roughly adjust the relative positional relationship of the second objective measurement means with respect to the subject's eye by using an anterior-segment observation image of the subject's eye. In other words, the second alignment means may be used to perform rougher alignment than the first alignment means.

[0043] <Control means> The control means may acquire ocular refractive power using a method other than the photorefraction method using the first objective measurement means. Alternatively, the control means may acquire ocular refractive power using the photorefraction method using the second objective measurement means. Alternatively, the control means may acquire both ocular refractive power using the first objective measurement means and ocular refractive power using the second objective measurement means. Of course, the control means may acquire the average value of the ocular refractive power using the first objective measurement means and the ocular refractive power using the second objective measurement means as the ocular refractive power.

[0044] The control means may set either a first measurement mode using the first objective measurement means or a second measurement mode using the second objective measurement means based on a switching signal for the measurement mode for measuring the ocular refractive power of the subject's eye. This allows the measurement mode to be smoothly set and measurements using different measurement methods to be easily started.

[0045] For example, the switching signal may be output by the examiner operating an operating means (for example, the operating unit 11 or the operating unit 210). As an example, the switching signal may be output by selecting a measurement mode, etc. Furthermore, for example, the switching signal may be output according to a measurement program that automatically proceeds with the measurement of the subject's eye. As an example, the switching signal may be output in at least one of the following cases: when good results cannot be obtained in one measurement mode, when the measurement takes more than a predetermined time, etc.

[0046] Although the above example illustrates a configuration in which the eye examination apparatus includes a first objective measurement means and a second objective measurement means, either of the objective measurement means may be provided as an attachment attached to the eye examination apparatus. For example, the eye examination apparatus may include the first objective measurement means, and the attachment may include the second objective measurement means. Of course, even in such a configuration, the two objective measurement means may share a portion of each other.

[0047] <Attachment> In this embodiment, the eye examination apparatus is equipped with a second objective measuring means, and by attaching an attachment to this eye examination apparatus, the ocular refractive power of the subject's eye may be objectively measured using a photorefraction method.

[0048] [Transformation optics] The attachment may include a conversion optical system (e.g., a light projecting optical system 110, a light receiving optical system 120) for converting a first objective optical system of the eye examination apparatus into a second objective optical system (e.g., a second measurement optical system 100) that objectively measures the ocular refractive power of the subject's eye using a photorefraction method. For example, by attaching the attachment, the conversion optical system is placed in the optical path of the first objective optical system, and the conversion optical system is used as a part of the first objective optical system, thereby converting it into the second objective optical system. For example, the configuration of the second objective optical system is converted so that a measurement beam is irradiated onto the fundus of the subject's eye, and the proportion of the reflected beam from the fundus at the pupil (movement of light) can be observed. Depending on whether the attachment is attached or detached, the ocular refractive power of the subject's eye using a method other than the photorefraction method and the ocular refractive power of the subject's eye using the photorefraction method can be obtained.

[0049] The transformation optical system may include at least one of a plurality of measurement light sources (e.g., measurement light source 111) arranged in a meridian direction based on the optical axis center of the transformation optical system, and a wide-angle lens (e.g., wide-angle lens 121) that widens the shooting angle of the objective optical system compared to when the attachment is not attached.

[0050] For example, the transformation optical system may include only a plurality of measurement light sources. In this case, the wide-angle lens may be removably provided in the optical path of the first objective optical system. By adding the transformation optical system to the first objective optical system of the ophthalmic examination device using an attachment and further inserting the wide-angle lens into the optical path of the first objective optical system, the measurement method of the subject's eye can be easily converted.

[0051] Furthermore, for example, the conversion optical system may include only a wide-angle lens. In this case, the multiple measurement light sources may be provided in the optical path of the first objective optical system. By providing the first objective optical system of the ophthalmic examination apparatus with multiple measurement light sources and adding a wide-angle lens to the first objective optical system as an attachment, the measurement method for the subject's eye can be easily converted. As described above, the multiple measurement light sources used in photorefraction measurement of the subject's eye may be shared with light sources of other optical systems provided in the ophthalmic examination apparatus, or may be provided exclusively for the purpose.

[0052] Furthermore, for example, the transformation optical system may include both a plurality of measurement light sources and a wide-angle lens. By adding the transformation optical system to the first objective optical system of the eye examination device using an attachment, the measurement method of the subject's eye can be easily changed.

[0053] By arranging such a wide-angle lens, the photographing angle of view of the first objective optical system of the eye examination apparatus can be switched between a photographing angle when measuring the ocular refractive power of the test eye using a method other than the photorefraction method and a photographing angle of view when measuring the ocular refractive power of the test eye using the photorefraction method. For example, with a method other than the photorefraction method, a narrow range of the test eye is photographed, thereby improving measurement accuracy compared to the photorefraction method. Also, for example, with the photorefraction method, a wide range of the test eye is photographed, thereby improving ease of measurement compared to the method other than the photorefraction method. Note that the first objective optical system may include an anterior eye observation optical system, and the photographing angle of view of the anterior eye may be switched by arranging the wide-angle lens.

[0054] <Distance measurement method> The attachment may include a distance measuring means (e.g., distance measuring unit 31) for measuring the distance from the subject's eye to the ophthalmic examination apparatus. For example, the distance measuring means may measure the distance from the subject's eye to the attachment, or may measure the distance from the subject's eye to the housing (e.g., housing unit 20). Furthermore, for example, the distance measuring means may measure the distance from the subject's eye to the attachment and add the length of the attachment to this to measure the distance from the subject's eye to the housing. Note that the distance from the subject's eye to the ophthalmic examination apparatus may be expressed as the distance to a predetermined component of the ophthalmic examination apparatus. For example, this may be a surface (front surface, rear surface, etc.) of the attachment or the housing, an optical component of the transformation optical system or the first objective optical system, etc.

[0055] The distance measurement means may be any means capable of measuring the distance between the subject's eye and the eye examination apparatus. For example, the distance measurement means may project an index light beam onto the cornea of ​​the subject's eye and measure the distance using an alignment index image based on the index light beam reflected by the cornea. That is, the distance measurement means may be an alignment optical system. Also, for example, the distance measurement means may measure the distance by emitting an optical signal toward the subject's eye and detecting a reflected signal of the optical signal reflected by the subject's eye. That is, the distance measurement means may be an optical detector. Also, for example, the distance measurement means may measure the distance by emitting an ultrasonic wave toward the subject's eye and detecting a reflected wave of the ultrasonic wave reflected by the subject's eye. That is, the distance measurement means may be an ultrasonic detector. Of course, other optical systems or detectors may also be used.

[0056] It is preferable to use an ultrasonic detector as the distance measuring means. In this case, the distance measuring means may include an ultrasonic transmitter (e.g., ultrasonic transmitter 31a) that transmits ultrasonic waves toward the subject's eye, and an ultrasonic receiver (e.g., ultrasonic receiver 31b) that receives ultrasonic waves reflected by the subject's eye. As mentioned above, in photorefraction measurement of the subject's eye, the imaging angle of view of the objective optical system is widened, but if the configuration uses ultrasonic waves, there is no effect associated with changes in the imaging angle of view, making it easy to measure the distance.

[0057] When the eye examination apparatus is configured to be capable of switching the measurement method of the eye refractive power of the subject's eye by attaching or detaching such an attachment to or from the eye examination apparatus, the eye examination apparatus may be provided with an attachment means, a connection means, a detection means, etc.

[0058] <Attachment means> The eye examination apparatus may include a mounting means (e.g., mounting section 23) to which the attachment is attached. The mounting means may be capable of fixing the attachment. For example, the mounting means may have a fitting mechanism for fitting the attachment. In this case, the mounting means may have either a convex or concave structure, and the attachment may have the other structure. Also, for example, the mounting means may have a connecting mechanism for connecting the attachment. In this case, the mounting means and the attachment may include ferromagnetic materials and be connected to each other by magnetic force. Of course, the mounting means may have a different mechanism than these, or may have a mechanism that combines at least one of a fitting mechanism, a connecting mechanism, and a different mechanism than these.

[0059] <Connection method> The eye examination device may include a connection means (e.g., electrical connection portion 24) that electrically connects the eye examination device and the attachment. The attachment becomes usable by connecting using the connection means. The connection means may enable transmission and reception of electrical signals via wireless communication. Alternatively, the connection means may enable transmission and reception of electrical signals via wired communication. As an example, the connection means may be a connector or the like.

[0060] The connecting means may be configured to electrically connect the attachment to the eye examination apparatus in response to the attachment. For example, the connecting means may be configured to directly contact the terminals and terminal holes of the connector in response to the attachment of the attachment. In this case, the connecting means may have either the terminal or the terminal hole structure, and the attachment may have the other structure.

[0061] Furthermore, the connection means may be configured to electrically connect the attachment to the ophthalmic examination apparatus without being linked to the attachment's attachment. For example, the connection means and the attachment may be configured to be in indirect contact with each other via a cable or the like. In this case, after the attachment is attached, connectors may be separately connected to the attachment and the connection means. Note that a cable may be fixed to the attachment and the connector of the cable may be brought into contact with the connection means to electrically connect them. Of course, the cable may be fixed to the connection means (in other words, the cable may be used as part of the connection means) and the connector of the cable may be brought into contact with the attachment to electrically connect them.

[0062] <Detection method> The eye examination apparatus may include a detection means (e.g., an attachment detection unit 23a, a connection detection unit 25) that detects at least one of the attachment of the attachment to the eye examination apparatus and the electrical connection between the eye examination apparatus and the attachment. The detection means is required to at least detect whether the attachment and the eye examination apparatus are in contact with each other when the attachment is attached to the eye examination apparatus. In this case, the detection means may be a contact-type detector (e.g., a physical sensor), a non-contact-type detector (e.g., an optical sensor, a magnetic sensor), or the like. The detection means is required to at least detect whether the eye examination apparatus and the attachment are electrically connected. In this case, the detection means may be a non-contact-type detector (e.g., a current sensor, a voltage sensor, or the like).

[0063] <Control means> Even when an attachment is attached to or detached from the eye examination apparatus, the eye examination apparatus can use the configuration of the control means described in the above-mentioned <Eye Examination Apparatus>. For example, the eye examination apparatus can obtain the ocular refractive power of the subject's eye by controlling at least one of the first objective optical system of the eye examination apparatus and the transformation optical system of the attachment. Furthermore, for example, various controls may be performed in conjunction with the attachment being attached or detached.

[0064] The control means may control the operation of the eye examination apparatus based on the detection signal from the detection means. For example, the control means may control the eye examination apparatus so as to change the operation when a detection signal is obtained indicating either attachment of the attachment to the eye examination apparatus or electrical connection between the eye examination apparatus and the attachment. Alternatively, the control means may control the eye examination apparatus so as to change the operation after detection signals are obtained indicating both attachment and electrical connection.

[0065] For example, the control means may automatically switch the mode from the first measurement mode using the first objective optical system to the second measurement mode using the second objective optical system (in other words, the first objective optical system and the transformation optical system) based on a detection signal from the detection means. Of course, for example, the control means may automatically switch the mode based on a switching signal generated by the examiner operating the operating means. In these cases, the control means may output notification information notifying that the setting has been changed from the first measurement mode to the second measurement mode by controlling at least one of a display means (e.g., the display unit 22), a sound generating means (e.g., a speaker), a notification means (e.g., a lamp), etc.

[0066] The control means may output guidance information that guides the examiner to change the setting from a first measurement mode using the first objective optical system to a second measurement mode using the second objective optical system, based on the detection signal from the detection means. For example, the guidance information may be information that guides the examiner to perform the following actions. For example, the guidance information may be information that prompts the examiner to change the setting from the first measurement mode to the second measurement mode, operate a switch or the like for switching between the first measurement mode and the second measurement mode, ensure a working distance between the subject's eye and the ophthalmic examination device, etc. Of course, the guidance information may be a combination of these pieces of information, or may be information different from these pieces of information.

[0067] In this case, the control means may control the display means to display the guidance information on the display means. Furthermore, for example, the control means may control the sound generation means to cause the sound generation means to generate the guidance information as sound. Furthermore, for example, the control means may control the notification means to display the guidance information by lighting or blinking the notification means. Note that the control means may execute a combination of these controls, or may execute a different control from these controls.

[0068] In the eye examination apparatus of this embodiment, the first objective optical system is an optical system that objectively measures the ocular refractive power of the subject's eye using a method other than photorefraction, but is not limited to this. The first objective optical system may be an optical system that can objectively acquire information about the subject's eye. For example, the first objective optical system may be an optical system that photographs the anterior segment of the subject's eye to acquire anterior segment observation image data of the subject's eye, corneal shape data of the subject's eye, etc. The first objective optical system may also be an optical system that photographs the fundus of the subject's eye to acquire tomographic image data of the fundus of the subject's eye, frontal image data of the fundus of the subject's eye, etc. The first objective optical system may also be an optical system that measures the subject's eye to acquire optical characteristics of the subject's eye, the ocular refractive power of the subject's eye, binocular vision function (amount of heterophoria, stereoscopic vision function, etc.), contrast sensitivity, etc.

[0069] More specifically, the eye examination device may be at least one of an optical coherence tomography, a scanning laser ophthalmoscope, a fundus camera, an intraocular pressure measuring device, an axial length measuring device, a corneal shape measuring device, a corneal curvature measuring device, an ultrasonic ophthalmoscope, an eye refractive power measuring device, etc. Alternatively, it may be a combination of these devices.

[0070] For example, by attaching an attachment to such an eye examination device, it is possible to convert the first objective optical system for objectively obtaining information about the eye to a second objective optical system for objectively measuring the ocular refractive power of the eye by photorefraction. Therefore, using a single eye examination device, it is possible to easily obtain information about the eye and the ocular refractive power of the eye by photorefraction.

[0071] Furthermore, in the eye examination apparatus of this embodiment, the second objective optical system is an optical system that objectively measures the ocular refractive power of the subject's eye using a photorefraction method, but is not limited to this. The second objective optical system may be an optical system that can objectively acquire information other than the ocular refractive power of the subject's eye. As an example, the second objective optical system may be an optical system that acquires at least one of information such as eye position information and interpupillary distance of the subject's eye.

[0072] For example, by attaching an attachment having such an optical system to an eye examination apparatus, it is possible to convert a first objective optical system for objectively acquiring the ocular refractive power of the subject's eye or information about the subject's eye into a second objective optical system for objectively measuring information different from the ocular refractive power of the subject's eye. Therefore, it is possible to easily acquire the ocular refractive power of the subject's eye or information about the subject's eye and information different from the ocular refractive power of the subject's eye using a single eye examination apparatus.

[0073] Of course, the control means may execute control based on a detection signal that detects at least one of the attachment of the attachment to the ophthalmic examination apparatus and the electrical connection between the ophthalmic examination apparatus and the attachment. For example, the control means may automatically switch from a first mode in which photographing, inspection, measurement, etc. are performed using a first objective optical system to a second mode in which photographing, inspection, measurement, etc. are performed using a second objective optical system, or may output guidance information for changing settings.

[0074] The present disclosure is not limited to the devices described in the present embodiment. For example, terminal control software (programs) that perform the functions of the above embodiments may be supplied to a system or device via a network or various storage media, and a control device (e.g., a CPU) of the system or device may read and execute the program.

[0075] <First Example> A first example of the eye examination apparatus according to this embodiment will be described.

[0076] <Device configuration> 1 and 2 are external views of an eye examination device 1. Fig. 1 shows the eye examination device 1 with an attachment attached. Fig. 2 shows the eye examination device 1 with the attachment removed. Here, a handheld eye refractive power measuring device is taken as an example of the eye examination device.

[0077] The eye examination apparatus 1 includes a handle unit 10, a housing unit 20, an attachment unit 30, etc. The handle unit 10 includes an operation unit 11, etc. The operation unit 11 is a button for inputting an operation signal for starting measurement of the subject's eye E.

[0078] The housing 20 has a presentation window 21, a display unit 22, a mounting unit 23, an electrical connection unit 24, etc. The presentation window 21 is formed of a transparent member (for example, a panel) such as acrylic resin or a glass plate. The display unit 22 displays an observed image of the anterior segment of the subject's eye E, measurement results, etc. The display unit 22 may be a touch panel that also functions as the operation unit 11, and may further have buttons or the like for inputting operation signals related to various settings.

[0079] The attachment unit 30 has a distance measurement unit 31, a wearing unit 32, an electrical connection unit 33, a presentation window 34, etc. The distance measurement unit 31 is an ultrasonic sensor that measures the distance from the subject's eye E to the attachment unit 30. The ultrasonic sensor has an ultrasonic transmitter 31a that transmits ultrasonic waves toward the subject's eye E, and an ultrasonic receiver 31b that receives ultrasonic waves reflected by the subject's eye E. The presentation window 34 is formed of a transparent member (e.g., a panel) such as acrylic resin or a glass plate.

[0080] In this embodiment, the attachment unit 30 is detachably attached to the housing unit 20. For example, the attachment unit 23 and the attachment unit 32 are made of a ferromagnetic material, and are attached to each other by their mutual magnetic force, and can be detached by applying a force greater than this magnetic force. Of course, the attachment unit 23 and the attachment unit 32 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.

[0081] The mounting unit 23 has a mounting detection unit 23a for detecting contact between the mounting unit 23 and the mounting unit 32. The mounting detection unit 23a may be a contact sensor (for example, a microswitch, etc.) or a non-contact sensor (for example, an optical sensor, a magnetic sensor, etc.). An output signal from the mounting detection unit 23a is input to the control unit 130. As a result, mounting of the attachment unit 30 to the housing unit 20 is detected.

[0082] Furthermore, in this embodiment, by attaching the attachment unit 30 to the housing unit 20, the electrical connection unit 33 of the attachment unit 30 is connected to the electrical connection unit 24 of the housing unit 20. For example, the electrical connection unit 33 is configured as a connector, and the electrical connection unit 24 is configured as a jack, and when connected to each other, the terminals and terminal holes come into contact, enabling transmission and reception of electrical signals. Note that the electrical connection unit 33 and the electrical connection unit 24 are not limited to a direct connection, and may be connected via a USB cable or the like (i.e., wired communication) to enable transmission and reception of electrical signals, or may be connected via Bluetooth (registered trademark) or the like (i.e., wireless communication) to enable transmission and reception of electrical signals.

[0083] The electrical connection unit 24 has a connection detection unit 25 for detecting the electrical connection between the electrical connection unit 33 and the electrical connection unit 24. The connection detection unit 25 may be a non-contact sensor (for example, a current sensor, a voltage sensor, etc.). An output signal from the connection detection unit 25 is input to the control unit 130. This detects the electrical connection between the attachment unit 30 and the housing unit 20.

[0084] The housing 20 houses a first measurement unit 40 for objectively measuring the ocular refractive power of the subject's eye E using a method other than the photorefraction method. Here, an example is shown in which a pattern index is projected onto the fundus of the subject's eye as a measurement light beam, and the ocular refractive power of the subject's eye E is objectively measured based on the reflected light of the measurement light beam. The attachment 30 houses a second measurement unit 90 for objectively measuring the ocular refractive power of the subject's eye E using the photorefraction method. For example, objective measurement using the photorefraction method involves objectively measuring the ocular refractive power of the subject's eye E from the proportion of fundus reflected light of the subject's eye E at the pupil.

[0085] In this embodiment, by attaching the attachment unit 30 to the housing unit 20, the measurement of the ocular refractive power of the subject's eye E can be converted from a measurement method other than the photorefraction method to a measurement method using the photorefraction method. In other words, the second measurement unit 90 functions as a conversion unit for converting the measurement method using the first measurement unit 40.

[0086] <1st measurement section> First, the first measurement unit 40 will be described. Fig. 3 is a schematic diagram of the first measurement unit 40. The first measurement unit 40 includes a first measurement optical system 50, a fixation target presenting optical system 60, an index projection optical system 70, an anterior segment observation optical system 80, etc. The first measurement optical system 50 objectively measures the ocular refractive power (e.g., spherical power, cylindrical power, astigmatic axis angle, etc.) of the subject's eye E using a method different from the photorefraction method. The fixation target presenting optical system 60 presents a fixation target to the subject's eye E. The index projection optical system 70 projects an alignment index onto the subject's eye E. The anterior segment observation optical system 80 captures an image of the anterior segment of the subject's eye E.

[0087] A beam splitter 41 is disposed in front of the subject's eye E. The beam splitter 41 guides a measurement light beam from the fixation target presenting optical system 60 to the subject's eye E. The beam splitter 41 also guides a reflected light beam from the anterior segment of the subject's eye E to the anterior segment observation optical system 80.

[0088] [First measurement optical system] The first measurement optical system 50 has a projection optical system 50a and a light-receiving optical system 50b in the transmission direction of the beam splitter 41. The projection optical system 50a includes a light source 51, a relay lens 52, a hole mirror 53, a prism 54, an objective lens 42, and the like. The light source 51 is positioned optically conjugate with the fundus. The opening of the hole mirror 53 is positioned optically conjugate with the pupil. The prism 54 is positioned away from the optically conjugate position with the pupil, and the light beam passing through the prism 54 is decentered with respect to the optical axis. The prism 54 is driven to rotate around the optical axis by a drive unit 54a. Instead of the prism 54, a parallel plane plate may be placed obliquely on the optical axis.

[0089] The light-receiving optical system 50b includes an objective lens 42, a prism 54, a hole mirror 53, a relay lens 55, a light-receiving diaphragm 56, a collimator lens 57, a ring lens 58, and an image sensor 59. In the light-receiving optical system 50b, the objective lens 42, the prism 54, and the hole mirror 53 are shared with the projection optical system 50a. The light-receiving diaphragm 56 is in an optically conjugate positional relationship with the fundus. The ring lens 58 is in an optically conjugate positional relationship with the pupil. The image sensor 59 is in an optically conjugate positional relationship with the fundus.

[0090] In the first measurement optical system 50, the measurement light beam emitted from the light source 51 passes through the relay lens 52, the hole mirror 53, the prism 54, the objective lens 42, and the beam splitter 41, and is projected as a spot-shaped light beam onto the fundus via the presentation window 21. This forms a point light source image on the fundus. At this time, the prism 54 rotates around the optical axis, and the pupil projection image (the projected light beam on the pupil) at the opening of the hole mirror 53 is eccentrically rotated at high speed. The measurement light beam is reflected by the fundus and is reflected by the hole mirror 53 via the beam splitter 41, the objective lens 42, and the prism 54. The reflected light beam further passes through the relay lens 55 and is focused at the position of the light receiving diaphragm 56, and is then focused on the image sensor 59 as a ring-shaped image (ring image) via the collimator lens 57 and the ring lens 58. An output signal from the image sensor 59 is input to the control unit 130 via an image processing unit 59a, and the eye refractive power is calculated.

[0091] The first measurement optical system 50 projects a measurement light beam from the light source 51 onto either the left or right eye, and extracts a ring-shaped light beam reflected from the fundus of the left or right eye and forms an image on the imaging element 59.

[0092] Furthermore, the first measurement optical system 50 may be an optical system different from that of this embodiment, as long as it has a projection optical system that projects a measurement light beam onto the fundus of the subject's eye E and a light-receiving optical system that receives the measurement light beam reflected by the fundus. For example, the first measurement optical system 50 may be an optical system that projects a spot index onto the fundus and detects the reflected light beam of the spot index on the fundus using a Shack-Hartmann sensor. For example, the first measurement optical system 50 may be a phase-contrast optical system that projects a slit onto the subject's eye E.

[0093] [Fixation target presentation optical system] The fixation target presenting optical system 60 has a light source 61, a fixation target plate 62, a projection lens 63, an objective lens 43, etc., arranged in the reflection direction of the beam splitter 41. The light source 61 illuminates the fixation target plate 62, thereby presenting a fixation target to the subject's eye E. The fixation target plate 62a is used to fixate the subject's eye E and measure its ocular refractive power. The drive unit 64 can fog the subject's eye E by moving the light source 61 and the fixation target plate 62 in the optical axis direction. The drive unit 64 can also move the fixation target plate 62 in the optical axis direction to move the presentation position of the fixation target relative to the subject's eye E.

[0094] [Indicator projection optical system] The target projection optical system 70 includes an XY target projection optical system 70a and a Z target projection optical system 70b. The XY target projection optical system 70a projects alignment targets for detecting the alignment state in the left-right and up-down directions (X and Y directions) of the subject's eye E. The Z target projection optical system 70b projects alignment targets for detecting the alignment state in the front-back direction (Z direction) of the subject's eye E.

[0095] The XY target projection optical system 70a includes a light source 71, a condenser lens 72, etc. The light source 71 emits near-infrared light. The alignment target light for XY detection emitted from the light source 71 is converted into a parallel beam (approximately parallel beam) by the objective lens 43.

[0096] The Z target projection optical system 70b includes a first target projection optical system and a second target projection optical system. The first target projection optical system projects an alignment target at infinity onto the cornea of ​​the subject's eye E. The second target projection optical system projects an alignment target at finite distance onto the cornea of ​​the subject's eye E.

[0097] The first target projection optical system includes point light sources 72a and 72b, collimator lenses 73a and 73b, etc. The point light sources 72a and 72b emit near-infrared light. The collimator lenses 73a and 73b convert the light beams emitted by the point light sources into parallel light beams (approximately parallel light beams). For example, a plurality of these point light sources and collimator lenses are arranged at 45-degree intervals on concentric circles based on the optical axis and symmetrically with respect to a vertical plane passing through the optical axis.

[0098] The second target projection optical system has point light sources 74a and 74b. The point light sources 74a and 74b emit near-infrared light. For example, these point light sources are arranged at a narrower angle than the point light sources of the first target projection optical system and are symmetrical with respect to a vertical plane passing through the optical axis. The second target projection optical system can also be used as an anterior segment illumination system for illuminating the anterior segment of the subject's eye E, as a target for measuring the corneal shape of the subject's eye E, etc.

[0099] The Z index projection optical system 70b may be configured to project at least one of a point-shaped index, a ring-shaped index (so-called Mayer ring, etc.), a line-shaped index, and the like.

[0100] [Anterior segment observation optical system] The anterior-segment observation optical system 80 has an objective lens 43, an imaging lens 81, an imaging element 82, etc., arranged in the reflection direction of the beam splitter 41. The imaging element 82 is positioned optically conjugate with the anterior segment of the subject's eye E, and receives a light beam reflected from the anterior segment. An output signal from the imaging element 82 is input to the control unit 130 and the display unit 22 via an image processing unit 83. The anterior-segment observation optical system 80 also serves as an optical system that detects an alignment target image formed on the cornea of ​​the subject's eye E, and the position of the alignment target image is detected by the image processing unit 83 and the control unit 130.

[0101] <Second measurement section> Next, the second measurement unit 90 will be described. Fig. 4 is a schematic configuration diagram of the second measurement unit 90. The second measurement unit 90 includes a second measurement optical system 100. The first measurement optical system 50 objectively measures the ocular refractive power of the subject's eye E by a photorefraction method.

[0102] [Second measurement optical system] The second measurement optical system 100 includes a light projecting optical system 110, a light receiving optical system 120, etc. In this embodiment, some of the optical members constituting the first measurement optical system 50 described above are also used as the optical members constituting the second measurement optical system 100.

[0103] The light projecting optical system 110 has at least a measurement light source 111. The measurement light source 111 emits near-infrared light. Multiple measurement light sources 111 are arranged on a concentric circle based on the optical axis (details will be provided later). The light receiving optical system 120 has at least a wide-angle lens 121, an image sensor 122, etc. The wide-angle lens 121 has the role of widening the photographing angle of view for photographing the anterior segment of the subject's eye E. The image sensor 122 is optically conjugate with the pupil of the subject's eye E.

[0104] In this embodiment, the anterior-eye-segment observation optical system 80 also serves as the light-receiving optical system 120, and the imaging element 82 of the anterior-eye-segment observation optical system 80 is used as the imaging element 122 of the light-receiving optical system 120. That is, the light-receiving optical system 120 has a wide-angle lens 121, an objective lens 42, the imaging lens 81, and an imaging element 82 (imaging element 122), etc. Furthermore, by disposing the wide-angle lens 121 in the optical path of the anterior-eye-segment observation optical system 80, the imaging angle of view of the anterior-eye-segment observation optical system 80 is widened. For example, the imaging angle of view in a first measurement mode (described later) and the imaging angle of view in a second measurement mode (described later) are changed depending on whether the attachment unit 30 is attached or not.

[0105] The measurement light source 111 and the wide-angle lens 121 are provided as an integrated member fixed to the base 101. Of course, the measurement light source 111 and the wide-angle lens 121 can also be provided as separate members. The measurement light source 111 has a plurality of measurement light sources, and the respective measurement light sources are arranged so as to be separated from each other in at least three meridian directions. Of course, the measurement light sources can be in any number of meridian directions (for example, one meridian direction, two meridian directions, four meridian directions, etc.).

[0106] In this embodiment, the measurement light sources 111 are arranged in four meridian directions. In addition, in this embodiment, the measurement light sources 111 are arranged in order on a virtual straight line extending in the meridian directions based on the optical axis center of the second measurement optical system 100. In one meridian direction, two sets are arranged symmetrically with the optical axis center of the wide-angle lens 121 as the reference.

[0107] As the measurement light source 111, eight sets of measurement light sources (measurement light source 111a, measurement light source 111b, measurement light source 111c, measurement light source 111d, measurement light source 111e, measurement light source 111f, measurement light source 111g, and measurement light source 111h) are arranged in four meridian directions. For example, the measurement light sources 111a to 111h are arranged at 45° intervals on a concentric circle outside the outer circumferential circle of the wide-angle lens 121. Of course, each measurement light source may be arranged at any position.

[0108] Each of the measurement light sources 111a to 111h has three light sources. For example, the three light sources in each measurement light source (for example, the three light sources 111a1, 111a2, and 111a3 in the measurement light source 111a) are arranged at predetermined intervals in the meridian direction (in other words, the radial direction) based on the optical axis center of the wide-angle lens 121. Each light source can be independently controlled by the control unit 130. For example, each light source can be independently controlled to be turned on and off, to adjust the light intensity, etc.

[0109] In the above description, the measurement light sources 111 are arranged symmetrically with respect to the optical axis center of the second measurement optical system 100, but the present invention is not limited to this. For example, the measurement light sources 111 may be arranged asymmetrically with respect to the optical axis center of the second measurement optical system 100. As an example, the measurement light sources 111 may be arranged on only one side in one meridian direction. In addition, although eight sets of measurement light sources 111 are used in the above description, the present invention is not limited to this. For example, any number of sets (e.g., three, four, five, six, etc.) of measurement light sources 111 may be used. In addition, although the above description describes a configuration in which the measurement light sources 111a to 111h each have three light sources, the present invention is not limited to this. For example, any number of light sources (e.g., two, four, five, etc.) may be used.

[0110] <Conversion of measurement method by attaching an attachment> In this embodiment, by attaching the attachment unit 30 to the housing unit 20, the first measurement optical system 50 and the second measurement optical system 100 are integrated, and the measurement method of the first measurement optical system 50 can be converted. More specifically, it is possible to convert from objective measurement, which is different from the photorefraction method, using the first measurement optical system 50 to objective measurement using the photorefraction method using the first measurement optical system 50 and the second measurement optical system 100.

[0111] In this configuration of the first measurement optical system 50 and the second measurement optical system 100, the measurement light beam emitted from the measurement light source 111 is irradiated onto both the fundus of the left eye and the right eye. The measurement light beam reflected from the fundus passes through the wide-angle lens 121, is reflected by the beam splitter 41, and is imaged by the image sensor 122 (image sensor 82) via the imaging lens 81. At this time, since the angle of view of the anterior segment is widened by the arrangement of the wide-angle lens 121, both the reflected light beam from the left eye and the reflected light beam from the right eye are imaged by the image sensor 122. The output signal from the image sensor 122 is input to the control unit 130 via the image processing unit 82a, and the ocular refractive power is calculated.

[0112] When the attachment unit 30 is attached, the target projection optical system 70 (second target projection optical system) of the first measurement optical system 50 is blocked. Therefore, the light projecting optical system 105 of the second measurement optical system 100 may be used for anterior eye illumination. In other words, the measurement light source 111 may have both the function of irradiating the test eye E with a measurement light beam and the function of illuminating the anterior eye. Of course, a dedicated light source for illuminating the anterior eye may be provided separately.

[0113] <Control unit> The control unit 130 includes a CPU (processor), RAM, ROM, etc. The CPU controls the driving of each unit in the eye examination apparatus 1. The RAM temporarily stores various types of information. The ROM stores various programs executed by the CPU, etc. The control unit 130 may be configured with multiple control units (i.e., multiple processors).

[0114] The control unit 130 is electrically connected to the operation unit 11, the display unit 22, the attachment detection unit 23a, the connection detection unit 25, the drive unit 54a, the drive unit 64, the image processing unit 59a, the image processing unit 82a, a non-volatile memory 131 (hereinafter, memory 131), etc. The control unit 130 is also electrically connected to the ultrasonic wave transmitting unit 31a, the ultrasonic wave receiving unit 31b, the measurement light source 111, etc. via the electrical connection unit 33 and the electrical connection unit 24.

[0115] The memory 131 is a non-transitory 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 USB memory, etc. can be used as the memory 131. The memory 131 may store the ocular refractive power of the subject's eye E, etc.

[0116] <Control action> The control operation of the eye examination apparatus 1 will be described.

[0117] The eye examination apparatus 1 can be set to one of two measurement modes: a first measurement mode in which the ocular refractive power of the subject's eye E is objectively measured using a method other than the photorefraction method, and a second measurement mode in which the ocular refractive power of the subject's eye E is objectively measured using the photorefraction method. For example, these measurement modes can be automatically switched depending on whether or not the attachment unit 30 is attached. Of course, the examiner may also be able to manually switch the measurement mode.

[0118] <Measurement method different from photorefraction method> First, an example will be given in which the attachment unit 30 is not attached to the housing unit 20 and eye refractive power is measured using only the first measurement unit 40. The control unit 130 detects that the attachment unit 30 is not attached, sets the first measurement mode, and executes control according to the first measurement mode. For example, in the first measurement mode, the eye examination device 1 (here, the housing unit 20) is brought closer to the subject's eye E, shortens the working distance from the subject's eye E to the eye examination device 1, and acquires a magnified anterior eye observation image of the subject's eye E (an image of a narrow range including the pupil). Furthermore, in order to measure eye refractive power more accurately, fine alignment is performed.

[0119] 5 shows an example of the display unit 22 in the first measurement mode. The examiner holds the handle 10 and brings the presentation window 21 close to the front of the subject's eye E. The examiner also instructs the subject to fixate on a fixation target (fixation target plate 62) through the presentation window 21. As a result, the anterior segment of the subject's eye E is imaged by the imaging element 82, and the anterior segment observation image 140, the alignment target image M1 by the XY target projection optical system 70a, the alignment target image at a finite distance (here, the Mayer ring image M2) and the alignment target image at infinity by the Z target projection optical system 70b, etc. are displayed on the display unit 22. Also, a reticle LT indicating the coordinates of the optical axes of the first measurement unit 40, etc. is displayed on the display unit 22.

[0120] The control unit 130 determines the misalignment in the X and Y directions between the subject's eye E and the main body (optical axis) of the ophthalmic examination apparatus 1 based on the output signal from the imaging element 82 and the output signal from a detection unit (not shown) that detects the two-dimensional position of the alignment target image M1. Furthermore, the control unit 130 determines the misalignment in the Z direction between the subject's eye E and the main body (optical axis) of the ophthalmic examination apparatus 1 by utilizing the change in the image interval between the Mayer ring images M2 based on the output signal from the imaging element 82. Furthermore, the control unit 130 increases or decreases the number of indicators G based on the amount of misalignment in the Z direction.

[0121] The examiner moves the main body of the ophthalmic examination apparatus 1 in the X and Y directions to position the alignment target image M1 within the reticle LT. The examiner also moves the main body of the ophthalmic examination apparatus 1 in the Z direction to set the indicator G to a predetermined number (or make the Mayer ring image M2 as thin as possible). This completes the alignment between the subject's eye E and the main body of the ophthalmic examination apparatus 1. The examiner also operates the operation unit 11. This starts measurement of the subject's eye E.

[0122] Based on an output signal from the operation unit 11, the control unit 130 turns on the light source 51 to irradiate the subject's eye E with a measurement light beam, and also captures an image of the light beam reflected from the fundus with the image sensor 59 to detect a ring image. The control unit 130 also analyzes and processes the ring image to determine the ocular refractive power in each meridian direction of the ring image, and performs predetermined arithmetic processing on the ocular refractive power.

[0123] In this embodiment, the ocular refractive power of the subject's eye E can be objectively measured using a method different from the photorefraction method. For example, the above control operation may be performed sequentially for the left eye and the right eye to obtain the ocular refractive power of the left eye and the ocular refractive power of the right eye, respectively. Each ocular refractive power (spherical power, cylindrical power, astigmatic axis angle, etc.) is displayed on the display unit 22 and stored in the memory 131.

[0124] <Photorefraction measurement> Next, an example will be given in which the attachment unit 30 is attached to the housing unit 20 and the eye refractive power is measured using the second measurement unit 90 and the first measurement unit 40.

[0125] The examiner attaches the attachment unit 30 to the housing unit 20. This brings the attachment unit 32 of the attachment unit 30 into contact with the attachment unit 23 of the housing unit 20, causing an output signal to be emitted from the attachment detection unit 23a. Furthermore, the electrical connection unit 33 of the attachment unit 30 and the electrical connection unit 24 of the housing unit 20 are electrically connected, causing an output signal to be emitted from the connection detection unit 25. Note that, with these electrical connections, the control unit 130 is able to control each component of the attachment unit 30 in addition to each component of the housing unit 20.

[0126] The control unit 130 automatically switches the measurement mode from a first measurement mode in which the ocular refractive power of the subject's eye E is objectively measured by a method different from the photorefraction method to a second measurement mode in which the ocular refractive power of the subject's eye E is objectively measured by the photorefraction method, based on the output signal from the wearing detection unit 23a and the output signal from the connection detection unit 25. Of course, the control unit 130 may switch the measurement mode based on the output signal from the wearing detection unit 23a, or may switch the measurement mode based on the output signal from the connection detection unit 25.

[0127] The control unit 130 executes control according to the second measurement mode. For example, in the second measurement mode, the ophthalmic examination apparatus 1 (here, the attachment unit 30) is moved away from the subject's eye E, the working distance from the subject's eye E to the ophthalmic examination apparatus 1 is increased, and an anterior segment observation image (a wide range image including the pupil) of the subject's eye E is obtained in a reduced size. In addition, rough alignment is performed to more simply measure the eye refractive power.

[0128] 6 shows an example of the display unit 22 in the second measurement mode. The examiner holds the handle 10 and brings the presentation window 34 close to the front of the subject's eye E. The examiner also instructs the subject to fixate the fixation light through the presentation window 34. For example, at least one light source of the measurement light source 111 may be turned on as a fixation light (bright spot). As a result, the anterior segment of the subject's eye E is imaged by the image sensor 122, and an anterior segment observation image 150 and the like are displayed on the display unit 22.

[0129] The examiner moves the main body of the eye examination apparatus 1 in the X, Y, and Z directions to bring the left and right eyes into the imaging field of view. This completes the alignment between the subject's eye E and the main body of the eye examination apparatus 1. The control unit 130 may analyze and process the anterior eye observation image 150, and when both the left and right eyes are detected, may notify the user that the alignment is complete by generating a sound or displaying a message. The examiner then operates the operation unit 11. This starts the measurement of the subject's eye E.

[0130] The control unit 130 acquires the distance from the subject's eye E to the attachment unit 30 using the distance measurement unit 31 based on the output signal from the operation unit 11. For example, the control unit 130 measures the distance from the subject's eye E to the front of the attachment unit 30 and adds the distance from the attachment unit 30 to the wide-angle lens 121 (a known value in design) to find the separation distance (measured distance) between the subject's eye E and the wide-angle lens 121.

[0131] Furthermore, based on an output signal from the operation unit 11, the control unit 130 turns on the measurement light source 111 to irradiate the subject's eye E with a measurement light beam, and causes the image sensor 122 to capture an image of the light beam reflected from the fundus.

[0132] In this embodiment, the light sources are turned on in sequence for each set of measurement light sources. For example, the control unit 130 turns on the light source 111a1 of the measurement light source 111a. The other measurement light sources 111b to 111h, as well as the light sources 111a2 and 111a3, are turned off. The output signal from the image sensor 122 when the light source 111a1 is turned on is stored in the memory 131 as a measurement image. After the control unit 130 acquires a measurement image with the light source 111a1 turned on, it turns off the light source 111a1 and turns on the next light source 111a2, and similarly acquires a measurement image. Furthermore, after the control unit 130 acquires a measurement image with the light source 111a2 turned on, it turns off the light source 111a2 and turns on the next light source 111a3, and similarly acquires a measurement image.

[0133] When the control unit 130 acquires a measurement image using three light sources in one set of measurement light source 111a, it sequentially performs measurements using the remaining sets of measurement light sources 111b to 111h. Note that the order in which the measurement light sources in each set are turned on and the order in which the three light sources included in each set are turned on are not limited to the above and may be any order.

[0134] 7 is a diagram illustrating the photorefraction method. Subsequently, the control unit 130 analyzes and processes each measurement image to determine the ocular refractive power of the subject's eye E. More specifically, the control unit 130 detects the ratio of the dimension in the pupil radial direction of the bright crescent in the pupil of the anterior eye segment included in each measurement image to the pupil diameter, and obtains the ocular refractive power using the following formula (see, for example, Japanese Patent Application Laid-Open No. 2006-149501):

[0135] R = 1 - { e L / 2 r ( A + L )}

[0136] Here, R denotes the ratio (B / 2r) of the size of the bright crescent K in the pupil to the pupil diameter. B denotes the length of the bright crescent K in the pupil radial direction. r denotes the pupil radius of the subject's eye E. A denotes the ocular refractive power of the subject's eye E. e denotes the distance from the end 121a of the wide-angle lens 121 to the measurement light source 111 (in FIG. 7, the light source 111a1 in the measurement light source 111a is exemplified). L is the reciprocal of the separation distance S between the subject's eye E and the wide-angle lens 121 (L=1 / S).

[0137] For example, assuming that other conditions are constant, the proportion R of the bright crescent K varies depending on the ocular refractive power A of the test eye E. That is, the ocular refractive power A of the test eye E is calculated from the proportion R of the bright crescent measured under constant conditions using the following formula:

[0138] A = { e L / 2 r ( 1 - R )} - L

[0139] The control unit 130 calculates spherical information (spherical power) in the meridian direction where the measurement light source 111a is arranged, based on the measurement image obtained by lighting the measurement light source 111a. For example, at this time, the control unit 130 acquires spherical information based on at least one of the measurement images obtained by lighting the three light sources 111a1 to 111a3. In this case, the average value of the spherical information for each light source may be acquired as the spherical information in the meridian direction of the measurement light source 111a. Alternatively, one of the spherical information for each light source may be selected and acquired as the spherical information in the meridian direction of the measurement light source 111a.

[0140] The control unit 130 similarly calculates the spherical information in the meridian direction for the other measurement light sources 111b to 111h. After acquiring the spherical information in all the meridian directions, the control unit 130 acquires the spherical power of the eye E based on the spherical information. Furthermore, the control unit 130 acquires the cylindrical power and the astigmatic axis angle of the eye E based on the spherical power in the meridian direction (spherical power distribution).

[0141] In this embodiment, the ocular refractive power of the subject's eye E can be objectively measured using the photorefraction method. For example, in the above control operation, since both the left and right eyes are included in the measurement image, the ocular refractive power of the left eye and the ocular refractive power of the right eye can be obtained by performing analysis processing on the left eye and the right eye separately. The ocular refractive powers are displayed on the display unit 22 and stored in the memory 131.

[0142] <Second Example> A second embodiment of the eye examination apparatus according to the present embodiment will be described below. Note that the same components in the first and second embodiments are denoted by the same reference numerals and will not be described again.

[0143] <Device configuration> 8 is an external view of the eye examination apparatus 200. Here, a stationary eye refractive power measurement apparatus is taken as an example of the eye examination apparatus. In the second embodiment, the second measurement optical system 100 is incorporated inside the housing as part of the first measurement optical system 50.

[0144] The eye examination apparatus 200 includes a moving stage 201, an operation unit 210, a driving unit 220, a face support unit 230, a display unit 240, a distance measurement unit 250, a measurement unit 260, and the like. The operation unit 210 has a button for inputting an operation signal for starting measurement of the subject's eye E. The operation unit 210 also has a lever for inputting an operation signal for moving the measurement unit 260 relative to the subject's eye E. The driving unit 220 moves the measurement unit 260 in the X, Y, and Z directions relative to the moving stage 201. The face support unit 230 supports the subject's face. For example, the face support unit 230 may include at least one of a forehead rest and a chin rest. The display unit 240 displays an observation image of the anterior segment of the subject's eye E, measurement results, and the like. The display unit 240 may be a touch panel that also functions as the operation unit 210. The distance measurement unit 250 is an ultrasonic sensor that measures the distance from the subject's eye E to the measurement unit 260. The measurement unit 260 objectively measures the ocular refractive power of the subject's eye E by a photorefraction method or a method other than the photorefraction method.

[0145] 9 is a schematic diagram of the measurement unit 260. The measurement unit 260 includes a first measurement optical system 50, a second measurement optical system 300, a fixation target presenting optical system 60, a target projection optical system 70, an anterior eye observation optical system 80, and the like.

[0146] The second measurement optical system 300 objectively measures the ocular refractive power of the subject's eye E using a photorefraction method. The second measurement optical system 300 includes a light-projecting optical system 310, a light-receiving optical system 320, and the like. The light-projecting optical system 310 includes at least a measurement light source 311. Like the measurement light source 111 described above, the measurement light source 311 includes eight sets of measurement light sources arranged in four meridian directions, each of which includes three light sources. The second measurement optical system 300 includes an objective lens 43, a wide-angle lens 321, an imaging lens 322, an imaging element 323, and the like, all arranged in the reflection direction of the beam splitter 41. The wide-angle lens 321 widens the imaging angle of the imaging element 323. The imaging element 323 is optically conjugate with the pupil of the subject's eye E and receives a light beam reflected from the anterior segment.

[0147] In the configuration of the second measurement optical system 300 in this case, the measurement light beam from the measurement light source 311 is reflected by the fundus, then reflected by the beam splitter 41, passes through the wide-angle lens 321 and the imaging lens 322, and is imaged by the imaging element 323. An output signal from the imaging element 323 is input to the control unit 130 and the display unit 240 via an image processing unit 323a. In this embodiment, the imaging angle of the imaging element 323 is set to a wide angle by the arrangement of the wide-angle lens 321, relative to the imaging angle of the imaging element 82. For example, the imaging element 82 has an imaging angle of view that allows imaging of one eye of the subject's eye E, and the imaging element 323 has an imaging angle of view that allows imaging of both eyes of the subject's eye E.

[0148] In this embodiment, the light receiving optical system 320 is disposed on the rear side (the side farther from the subject's eye) than the objective lens 43, but is not limited to this. For example, the light receiving optical system 320 may be disposed on the front side (the side closer to the subject's eye) of the objective lens 43. In this case, the optical path may be branched by a half mirror or the like between the beam splitter 41 and the objective lens 42, and a wide-angle lens 321, an imaging lens 322, an imaging element 323, etc. may be disposed.

[0149] <Control action> The control operation of the eye examination apparatus 200 will be described.

[0150] The eye examination apparatus 200 can also be set to one of two measurement modes: a first measurement mode in which the ocular refractive power of the subject's eye E is objectively measured using a method other than the photorefraction method, and a second measurement mode in which the ocular refractive power of the subject's eye E is objectively measured using the photorefraction method. For example, these measurement modes can be switched based on the examiner's operation of the operation unit 210 (or the display unit 240).

[0151] <Measurement method different from photorefraction method> The examiner operates the operation unit 210 and operates a button (not shown) for selecting a measurement mode for the subject's eye E. The control unit 130 sets the first measurement mode based on the output signal from the operation unit 210, and executes control according to the first measurement mode.

[0152] The examiner instructs the subject to place their face against the face support part 230 and fixate on the fixation target (fixation target plate 62). As a result, the anterior segment of the subject's eye E and each alignment target image are captured by the image sensor 82. The control part 130 detects the corneal vertex position using each alignment target image, and drives the drive part 220 based on the deviations in the X, Y, and Z directions of the corneal vertex position relative to the alignment reference position, thereby completing auto-alignment between the subject's eye E and the main body of the ophthalmic examination apparatus 1.

[0153] The examiner also operates the operation unit 210 to start measurement of the subject's eye E. Based on the output signal from the operation unit 210, the control unit 130 controls the light source 51, the image sensor 59, etc., and analyzes and processes the ring image, similarly to the first embodiment, to measure the ocular refractive power of the subject's eye E.

[0154] <Photorefraction measurement> The examiner operates the operation unit 210 and operates a button (not shown) for selecting a measurement mode for the subject's eye E. The control unit 130 sets the second measurement mode based on the output signal from the operation unit 210 and executes control according to the second measurement mode.

[0155] In the second embodiment, the wide-angle lens 321 is not disposed on the optical axis of the fixation target presenting optical system 60, so that a fixation target (fixation target plate 62) can be used to guide the fixation of the subject's eye E even in photorefraction measurement of the subject's eye E. Of course, at least one light source of the measurement light source 311 may be turned on as a fixation lamp (bright spot). The anterior segment of the subject's eye E is imaged by the image sensor 323 and displayed on the display unit 240 as an anterior segment observation image.

[0156] The control unit 130 detects position information (e.g., coordinates) of the left and right eyes using the brightness of the anterior eye observation image, and drives the drive unit 220 based on the position information to bring the left and right eyes within the imaging angle of view of the image sensor 323. This completes auto-alignment between the subject's eye E and the main body of the eye examination apparatus 200. The control unit 130 also acquires the distance from the subject's eye E to the measurement unit 260 using the distance measurement unit 250. Note that the separation distance (measured distance) between the subject's eye E and the wide-angle lens 321 can be calculated by measuring the distance from the subject's eye E to the front of the measurement unit 260 and adding the distance from the measurement unit 260 to the wide-angle lens 321 (a design-known value).

[0157] The examiner operates the operation unit 210 to start measurement of the subject's eye E. The control unit 130 turns on the measurement light sources 311 in sequence based on the output signal from the operation unit 210, and captures each measurement image with the image sensor 323. The control unit 130 also measures the ocular refractive power of the subject's eye E based on the proportion of the crescent K formed in the pupil of the subject's eye E.

[0158] The above-described eye examination apparatus 1 and eye examination apparatus 200 can be used to perform at least one of a first measurement mode using a method different from the photorefraction method and a second measurement mode using the photorefraction method. When acquiring the ocular refractive power of the subject's eye E, the first measurement mode requires more accurate alignment of the main body (housing unit 20 or measurement unit 260) of the eye examination apparatus 1 with respect to the subject's eye E. On the other hand, the second measurement mode does not require strict alignment of the main body (attachment unit 30 or measurement unit 260) of the eye examination apparatus 1 with respect to the subject's eye E; it is sufficient to be able to capture an image of at least the anterior segment of the subject's eye E. In other words, the tolerance for alignment of the subject's eye E differs between the first measurement mode and the second measurement mode. Therefore, for example, when proper alignment cannot be achieved or satisfactory measurement results of the subject's eye E cannot be obtained when the first measurement mode is applied, simple measurement results can be efficiently obtained by switching to the second measurement mode.

[0159] As described above, the attachment of this embodiment is attached to an ophthalmic examination apparatus having a first objective optical system for objectively acquiring information about the subject's eye, and includes a conversion optical system for converting the first objective optical system into a second objective optical system for objectively measuring the ocular refractive power of the subject's eye by photorefraction. This makes it possible to easily acquire information about the subject's eye and the ocular refractive power of the subject's eye measured by photorefraction using a single ophthalmic examination apparatus, and is capable of handling photography, measurement, examination, etc. according to various conditions of the subject's eye.

[0160] The transformation optical system of the attachment of this embodiment includes at least one of a plurality of measurement light sources arranged in the meridian direction based on the optical axis center of the transformation optical system, and a wide-angle lens that widens the angle of view of the objective optical system of the eye examination device compared to when the attachment is not attached. As a result, by attaching the attachment, the objective optical system can be easily converted into a photorefraction optical system, making it possible to accommodate various conditions of the examined eye.

[0161] The attachment of this embodiment also includes a distance measurement unit for measuring the distance from the subject's eye to the eye examination device. When measuring the eye refractive power of the subject's eye using the photorefraction method, it is necessary to determine the measurement distance (working distance) of the subject's eye, and providing the distance measurement unit makes it possible to properly obtain the eye refractive power. While it is possible to use the distance measurement unit provided in the eye examination device, it may be difficult to obtain results depending on the configuration of the distance measurement unit when the attachment is attached. For this reason, providing the distance measurement unit in the attachment makes it possible to more reliably determine the measurement distance.

[0162] Furthermore, in the attachment of this embodiment, the distance measurement unit includes an ultrasonic transmitter that transmits ultrasonic waves toward the test eye and an ultrasonic receiver that receives ultrasonic waves reflected by the test eye. In photorefraction measurements of the test eye, the imaging angle of the objective optical system is widened. Therefore, for example, in a configuration that measures distance based on an alignment target image or a bright spot image projected onto the test eye, these images are captured small along with the test eye, making detection difficult. On the other hand, in a configuration that uses ultrasonic waves, the transmission and reception of ultrasonic waves are not affected by changes in the imaging angle of the objective optical system, making it easier to measure distance.

[0163] The eye examination apparatus of this embodiment also includes a mounting section to which the attachment is attached and a connecting section that electrically connects the eye examination apparatus and the attachment, and the attachment can be used by connecting it using the connecting section. Therefore, in photorefraction measurement of the subject's eye, irradiation of the measurement light beam from the light source and imaging of the reflected light beam from the fundus of the subject's eye can be easily controlled. For example, the lighting of each light source and imaging by the detector can be easily synchronized.

[0164] The eye examination apparatus of this embodiment detects at least one of the attachment of the attachment to the eye examination apparatus and the electrical connection between the eye examination apparatus and the attachment, and controls the operation of the eye examination apparatus based on the detection signal. Depending on whether the attachment is attached or detached, the eye refractive power of the subject's eye can be efficiently measured using one of the measurement methods.

[0165] Furthermore, the ophthalmic examination apparatus of this embodiment automatically switches modes from a first mode using the first objective optical system to a second mode using the second objective optical system based on a detection signal that detects the attachment and electrical connection of the attachment. This allows the examiner to smoothly start photorefraction measurement simply by attaching the attachment.

[0166] In addition, in the eye examination apparatus of this embodiment, the first objective optical system objectively measures the ocular refractive power of the subject's eye using a method other than the photorefraction method. That is, the eye examination apparatus can measure the ocular refractive power of the subject's eye using a method other than the photorefraction method, and further, by attaching an attachment, the ocular refractive power of the subject's eye can be measured using the photorefraction method. Therefore, the mode can be appropriately selected depending on, for example, the subject's age and the quality of the measurement results obtained using each measurement method.

[0167] Furthermore, the eye examination apparatus of this embodiment acquires the ocular refractive power by controlling at least one of a first objective measurement unit for objectively measuring the ocular refractive power of the subject's eye using a method other than the photorefraction method and a second objective measurement unit for objectively measuring the ocular refractive power of the subject's eye using the photorefraction method. This allows the ocular refractive power of the subject's eye to be acquired in accordance with various situations, for example. As an example, the ocular refractive power of the subject's eye can be acquired using an objective measurement unit suited to the purpose, use, measurement accuracy, etc.

[0168] In the eye examination apparatus of this embodiment, the first objective measurement means measures the ocular refractive power of one of the examinee's eyes by projecting a measurement beam onto the fundus of the eye, and the second objective measurement means measures the ocular refractive power of both of the examinee's eyes by projecting a measurement beam onto the fundus of the eye. Therefore, for example, the first objective measurement means requires stricter (severe) alignment than the second objective measurement means, but can improve measurement accuracy. For example, the second objective measurement means has lower measurement accuracy than the first objective measurement means, but can easily and efficiently obtain measurement results. The second objective measurement means may also be used for screening of the examinee's refractive error, etc.

[0169] In the eye examination apparatus of this embodiment, the first objective measurement means includes a first detector that receives a measurement light beam reflected by the fundus of the subject's eye and is arranged at a position conjugate with the fundus of the subject's eye. The second objective measurement means includes a second detector that receives a measurement light beam reflected by the fundus of the subject's eye and is arranged at a position conjugate with the pupil of the subject's eye. In other words, the first objective measurement means is a fundus conjugate system, and the second objective measurement means is a pupil conjugate system. This allows, for example, two measurement methods to be used depending on the situation when measuring the ocular refractive power of the subject's eye.

[0170] In the eye examination apparatus of this embodiment, the first objective measurement means projects a pattern index as a measurement light beam onto the fundus of the subject's eye, receives a reflected light beam from the fundus of the subject's eye by the first detector, and acquires the ocular refractive power based on the reflected light beam received by the first detector. For example, the reflected light beam may be extracted as a ring image, and the ocular refractive power may be acquired based on the ring image. As a result, for example, by using the first objective measurement means, it is possible to obtain information in more meridian directions than by using the second objective measurement means (photorefraction method), and therefore the ocular refractive power of the subject's eye can be measured with high accuracy.

[0171] The eye examination apparatus of this embodiment also includes a first alignment unit for photographing the subject's eye and adjusting the positional relationship between the subject's eye and the first objective measurement unit, and a second alignment unit for photographing the subject's eye at a wider angle than the first alignment unit and adjusting the positional relationship between the subject's eye and the second objective measurement unit. This allows for appropriate alignment for each method when measuring the ocular refractive power of the subject's eye. For example, in measurement methods other than the photorefraction method, strict alignment may be performed because a narrow area of ​​the subject's eye is photographed. In the photorefraction method, rough alignment may be performed because a wide area of ​​the subject's eye is photographed.

[0172] Furthermore, the eye examination apparatus of this embodiment selects either a first measurement mode using the first objective measurement means or a second measurement mode using the second objective measurement means based on a switching signal for the measurement mode for measuring the ocular refractive power of the subject's eye. This allows the examiner to smoothly select the measurement mode and easily start measurements using different measurement methods.

[0173] In the eye examination apparatus of this embodiment, the first objective measuring means has an anterior eye imaging optical system for imaging the anterior eye, and the detector of the second objective measuring means is also used as the detector of the anterior eye imaging optical system. This makes it possible to measure eye refractive power using a method other than the photorefraction method or the photorefraction method with a simple configuration without providing a dedicated detector for each optical system.

[0174] <Example of transformation> In the first embodiment, a configuration in which the attachment unit 30 is detachably attached to the handheld eye examination apparatus 1 has been described as an example, but the present invention is not limited to this. Of course, the attachment unit 30 may be detachably attached to a stationary eye examination apparatus. For example, if the stationary eye examination apparatus is equipped with an optical system for objectively measuring the ocular refractive power of the subject's eye E using a method other than the photorefraction method, attaching the attachment unit 30 can convert the optical system to photorefraction measurement.

[0175] In the first embodiment, the attachment unit 30 is described as having the measurement light source 111 and the wide-angle lens 121, but the present invention is not limited to this. For example, the attachment unit 30 may be configured to have only the measurement light source 111, and the wide-angle lens 121 provided inside the housing unit 20. Furthermore, for example, the attachment unit 30 may be configured to have only the wide-angle lens 121, and the measurement light source 111 provided inside the housing unit 20.

[0176] When the attachment unit 30 includes only the measurement light source 111, the wide-angle lens 121 may be provided so as to be insertable and detachable in the optical path from the presentation window 21 to the image sensor 122. As an example, the wide-angle lens 121 may be provided near the objective lens 43, near the image sensor 81, etc. The control unit 130 may insert and remove the wide-angle lens 121 in conjunction with the attachment and detachment of the attachment unit 30, electrical connection of the attachment unit 30, selection of the first measurement mode or the second measurement mode by the examiner, etc., and may switch the angle of view of the subject's eye E for imaging depending on each measurement mode.

[0177] Furthermore, an imaging element different from imaging element 122 may be provided in addition to wide-angle lens 121, and the optical path may be branched along the way, with these optical components fixedly disposed. As an example, the optical path may be branched at any position between objective lens 43 and imaging lens 81. Control unit 130 may switch the imaging element to be used in conjunction with each measurement mode.

[0178] When the attachment unit 30 is equipped with only the wide-angle lens 121, the light source of the target projection optical system 70 may also be used as the measurement light source 111 (details will be described later). Of course, the measurement light source 111 may be provided separately from the light source of the target projection optical system 70. The control unit 130 may switch the light source to be used in conjunction with each measurement mode.

[0179] In the second embodiment, the stationary ophthalmic examination apparatus 200 is described as having the first measurement optical system 50 and the second measurement optical system 300, but the present invention is not limited to this. Of course, a handheld ophthalmic examination apparatus may be configured as having the first measurement optical system 50 and the second measurement optical system 300. In other words, a handheld ophthalmic examination apparatus may be provided with both an optical system for objectively measuring the ocular refractive power of the subject's eye E by a method other than the photorefraction method and an optical system for objectively measuring the ocular refractive power of the subject's eye E by the photorefraction method.

[0180] In the second embodiment, the measurement unit 260 is described as having the measurement light source 311 of the light-projecting optical system 310 and the wide-angle lens 321 and the image sensor 323 of the light-receiving optical system 320, but the present invention is not limited to this. For example, the light source of the target projection optical system 70 may also serve as the measurement light source 311 (details will be described later). Furthermore, for example, the wide-angle lens 321 may be removably provided in the optical path from the presentation window 261 to the image sensor 82, and the image sensor 82 of the anterior-segment observation optical system 80 may also serve as the image sensor 323. Of course, the measurement light source 311 and the wide-angle lens 321 may be provided as an integrated member, and this member may be inserted or removed in conjunction with each measurement mode.

[0181] In the first embodiment, when the imaging element 82 of the anterior-segment observation optical system 80 and the imaging element 122 of the light-receiving optical system 120 are used together, the settings of the imaging element may be changed depending on each measurement mode. Similarly, in the second embodiment, when the imaging element 82 of the anterior-segment observation optical system 80 and the imaging element 323 of the light-receiving optical system 320 are used together, the settings of the imaging element may be changed depending on each measurement mode. For example, at least one of the exposure time, gain, etc. of the imaging element may be adjusted to an appropriate value.

[0182] In the first embodiment, when the light source of the index projection optical system 70 is used as the measurement light source 111 of the projection optical system 110, the setting of the light source may be changed depending on each measurement mode. Similarly, in the second embodiment, when the light source of the index projection optical system 70 is used as the measurement light source 311 of the projection optical system 310, the setting of the light source may be changed depending on each measurement mode. For example, the amount of light irradiated from the light source may be adjusted to an appropriate value.

[0183] In the first embodiment, the configuration in which the measurement light source 111 is used as a fixation light has been described as an example, but this is not limiting. For example, a light source different from the measurement light source 111 may be provided separately as a fixation light, and a bright spot may be formed by turning on the light source. In this case, the light source may be provided on the optical axis or near the optical axis. In addition, in this case, the measurement light source 111 or a light source different from the measurement light source 111 may be flashed to attract the attention of the subject's eye E.

[0184] By attaching the attachment unit 30 and positioning the wide-angle lens 121 on the optical axis of the fixation target presenting optical system 60, the working distance of the subject's eye E becomes longer in the second measurement mode than in the first measurement mode, and the fixation target plate 62 cannot be seen. For this reason, as described above, the measurement light source 111 can be used as a fixation light as well, or a new fixation light can be prepared to guide the fixation of the subject's eye E. Of course, an optical element (lens, etc.) may be inserted on the optical axis of the fixation target presenting optical system 60 to adjust it so that the fixation target plate 62 can be seen.

[0185] In the second embodiment, too, there is a possibility that the fixation target plate 62 may not be visible depending on the position at which the wide-angle lens 321 is inserted, removed, or fixed. For this reason, the measurement light source 311 may be used as a fixation light, or a separate light source for the fixation light may be provided. Of course, the fixation light may be flashing.

[0186] In the first embodiment, a configuration has been described in which either the first measurement mode or the second measurement mode is automatically set in response to the attachment or detachment of the attachment unit 30, but the present invention is not limited to this. For example, guidance information may be output to guide the examiner in changing the setting from the first measurement mode to the second measurement mode (or from the second measurement mode to the first measurement mode) in response to the attachment or detachment of the attachment unit 30. As an example, the guidance information may be an audio guide instructing the examiner on the next operation, a message display prompting the examiner to change the setting, or the like. This allows the examiner to set up photorefraction measurement without hesitation after attaching the attachment, allowing the measurement to start smoothly.

[0187] In the first and second embodiments, the distance from the subject's eye E to the eye examination device is acquired by transmitting and receiving ultrasound waves using the distance measurement unit 31 or the distance measurement unit 250. However, the present invention is not limited to this. For example, a distance measurement element may be placed in front of the subject's face, and the distance from the subject's eye E to the eye examination device may be acquired by capturing an image of the distance measurement element together with the anterior segment of the subject's eye E. In this case, the distance measurement element may have known dimensions, and a figure or scale of a predetermined size may be used. The control unit 130 may estimate the distance from the subject's eye E to the eye examination device based on the actual length of the distance measurement element, its length on the anterior segment observation image, and a change in imaging magnification due to the placement of the wide-angle lens 121. In addition, if the interpupillary distance of the subject's eye E has been obtained in advance, it is also possible to estimate the distance from the subject's eye E to the eye examination device based on the actual interpupillary distance of the subject's eye E, the interpupillary distance on the anterior eye observation image, and the change in shooting magnification due to the placement of the wide-angle lens 121.

[0188] In the first and second embodiments, the index projection optical system 70 is configured to project a Mayer ring image, and the light source in the index projection optical system 70 and the measurement light source in the projection optical system 110 or 310 are selectively turned on in the first measurement mode and the second measurement mode, but the present invention is not limited to this. For example, the index projection optical system 70 may be configured to project a dot-like (or line-like) target image instead of a Mayer ring image.

[0189] In aligning the eye examination apparatus with the subject's eye E, the alignment state in the Z direction can be determined without using a Mayer ring image, as long as the image ratio between the alignment target image at infinity and the alignment target image at a finite distance can be detected. In photorefraction measurement of the subject's eye E, multiple measurement light sources are arranged in the meridian direction, and measurement images synchronized with the lighting of each light source are acquired to calculate the ocular refractive power. Therefore, if the target projection optical system 70 is configured to project a point-like target image to perform alignment, it is also possible to use the target projection optical system 70 to irradiate measurement light beams from each meridian direction, and the light source of the target projection optical system 70 can also be used as the measurement light source for the projection optical system 110 or the projection optical system 310. In other words, the target projection optical system 70 may serve both to project an alignment target onto the subject's eye E and to irradiate measurement light beams in photorefraction measurement.

[0190] In this way, the eye examination apparatus may share the light source of the projection optical system that projects light toward the anterior segment (here, the target projection optical system 70 that also serves as an anterior segment illumination) and the measurement light source of the photorefraction measurement optical system (here, the projection optical system 110 or the projection optical system 310). This makes it possible to measure the eye refractive power using a method other than the photorefraction method or the photorefraction method with a simple configuration, without providing a dedicated light source for each optical system.

[0191] In the first and second embodiments, a configuration has been described in which a patterned target light beam is projected onto the fundus of the subject's eye E and the reflected light beam of the measurement light beam from the fundus is extracted as a ring image, thereby measuring the ocular refractive power using a method other than the photorefraction method. However, the present invention is not limited to this. For example, a configuration may be adopted in which the measurement light beam is scanned over the fundus of the subject's eye, the reflected light beam of the measurement light beam reflected by the fundus is detected, and the ocular refractive power is measured using a method other than the photorefraction method based on the phase difference signal. For example, this configuration also makes it possible to obtain information in more meridian directions than the photorefraction method, thereby enabling the ocular refractive power of the subject's eye to be measured with high accuracy.

[0192] In the first and second embodiments, the configuration for acquiring the ocular refractive power of the subject's eye E in photorefraction measurement (measurement in the second measurement mode) using the second measurement optical system 100 or the second measurement optical system 300 has been described as an example. However, the present invention is not limited to this. The second measurement optical system may be an optical system that acquires data other than the ocular refractive power of the subject's eye, and such data may be acquired in the measurement in the second measurement mode. For example, in the second measurement mode, since both the left and right eyes are included in the measurement image, it is possible to acquire information such as the interpupillary distance and eye position information of the left and right eyes. For example, the control unit 130 may detect the pupil centers of the left and right eyes by analyzing the measurement image and use the position information (coordinates) to calculate the interpupillary distance. Furthermore, for example, the control unit 130 may detect the pupil centers of the left and right eyes by analyzing the measurement image and then calculate eye position information (for example, the presence and degree of strabismus or heterophoria) from the relationship between the position information (coordinates) and the bright spot.

[0193] Regardless of the measurement mode of the eye E, when the refractive power of the left eye and the refractive power of the right eye are separately obtained, the possibility of anisometropia may be determined based on the difference between these refractive powers.

[0194] In the first and second embodiments, the refractive power of the subject's eye E can be measured by at least one of a method other than the photorefraction method and the photorefraction method. Therefore, for example, when both measurement methods are performed on the subject's eye E, the first-eye refractive power measured by a method other than the photorefraction method and the second-eye refractive power measured by the photorefraction method may be output so as to be comparable. As an example, the first-eye refractive power and the second-eye refractive power may be displayed side by side, or may be displayed by switching between them. Of course, the output format is not limited to display, and may be printed, etc. [Explanation of symbols]

[0195] 1. Handheld eye examination device 20 Housing 30 Attachment part 50 1st measurement optical system 90 Second measurement optical system 130 control section 200 Stationary eye examination device 260 Measuring section 300 Second measurement optical system

Claims

1. An attachment to be attached to an eye examination apparatus having a first objective optical system for objectively acquiring information on a subject's eye, An attachment characterized by comprising a conversion optical system for converting the first objective optical system into a second objective optical system that objectively measures the ocular refractive power of the subject's eye using a photorefraction method.

2. In the attachment of claim 1, An attachment characterized in that the transformation optical system includes at least a plurality of measurement light sources arranged on an imaginary line extending in a meridian direction with the center of the optical axis of the transformation optical system as a reference.

3. The attachment of claim 1 or 2, The attachment further comprises a distance measuring means for measuring the distance from the eye to be examined to the eye examination apparatus.

4. An eye examination device to which the attachment of any one of claims 1 to 3 is attached, a mounting means to which the attachment is mounted; a connecting means for electrically connecting the eye examination apparatus and the attachment; Equipped with An eye examination apparatus characterized in that the attachment becomes usable by connecting it using the connecting means.

Images