JP7779111B2 - Eye examination device and eye examination program - Google Patents

Description

This disclosure relates to an eye examination device and an eye examination program.

Ophthalmological examination devices that objectively obtain the refractive power of a subject's eye are known. For example, the refractive power of the subject's eye can be measured by projecting a measurement beam of light onto the fundus of the subject's eye and receiving the beam of light reflected from the fundus (see Reference 1).

Note that there are two types of eye examination devices: stationary types such as those described in Reference 1, and handheld types such as those described in Reference 2.

Japanese Patent Application Laid-Open No. 2006-187483 JP 2012-183123 A

However, obtaining ocular refractive power is required in a variety of situations depending on the examiner's or subject's purpose and application. For example, there are situations where high accuracy is required, situations where simple measurement is required, situations where efficient measurement is required, etc. For this reason, there is a need for a system that can accommodate measurements tailored to the situation.

In consideration of the above problems, the technical objective of this disclosure is to provide an eye examination device that can acquire the ocular refractive power of the subject's eye according to the situation.

To solve the above problems, the present invention is characterized by the following configuration.

An eye examination apparatus according to a first aspect of the present disclosure is an eye examination apparatus characterized by comprising a first objective measurement means for objectively measuring the ocular refractive power of a subject's eye using a method different from the photorefraction method, a second objective measurement means for objectively measuring the ocular refractive power of the subject's eye using the photorefraction method, and a control means for controlling at least one of the first objective measurement means and the second objective measurement means to obtain the ocular refractive power.
An eye examination program according to a second aspect of the present disclosure is an eye examination program for use in an eye examination device that includes a first objective measuring means that objectively measures the ocular refractive power of a subject's eye using a method different from the photorefraction method, and a second objective measuring means that objectively measures the ocular refractive power of the subject's eye using the photorefraction method, and is characterized in that, when executed by a processor of the eye examination device, the eye examination program causes the eye examination device to execute a control step of controlling at least one of the first objective measuring means and the second objective measuring means to obtain the ocular refractive power.

FIG. 1 is an external view of a handheld eye examination device with an attachment attached thereto. FIG. 2 is an external view of the handheld eye examination device with the attachment removed. FIG. 2 is a schematic diagram illustrating the configuration of a first measurement unit. FIG. 2 is a schematic diagram illustrating the configuration of a second measurement unit. 10 is an example of a display unit in a first measurement mode. 10 is an example of a display unit in a second measurement mode. FIG. 1 is a diagram illustrating a photorefraction method. FIG. 1 is an external view of a stationary eye examination device. FIG. 2 is a schematic diagram illustrating the configuration of a measurement unit.

<Overview>
An overview of an eye examination device and its attachments according to an embodiment of the present disclosure will be described. Items classified in <> below may be used independently or in association 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.

<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.

The eye examination device may also include a first objective measurement means (e.g., first measurement unit 40, measurement 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 measurement means may be configured to include at least a first objective measurement optical system (e.g., first measurement optical system 50) as part of the first objective measurement means.

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

The eye examination device may also include a control means (e.g., control unit 130) that controls at least one of the first objective measurement means and the second objective measurement means to obtain ocular refractive power.

<First objective measuring 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 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.

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 the reflected light beam from the fundus using a first detector. In this case, the first detector may be positioned at a position conjugate with the fundus of the subject's eye.

Also, for example, the first objective measurement means may be an objective measurement means that projects a pattern index onto the fundus of the subject's eye as a measurement light beam and receives a reflected light beam reflected by the fundus using a first detector. In this case, the control means may obtain 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 obtained based on the ring image. As another example, the reflected light beam may be detected using a Shack-Hartmann sensor to obtain the ocular refractive power. In other words, the first objective measurement means may be an imaging-type objective measurement means. In other words, the first objective measurement means may be an objective measurement means that measures the ocular refractive power using a refractometer method.

Also, 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 the reflected light beams reflected by the fundus with a first detector. In this case, a spot light may be projected onto the subject's eye. In this case, the control means may obtain 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.

Also, 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 the reflected light beam reflected by the fundus with 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.

<Second objective measuring 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, the second objective measuring means can easily and efficiently obtain measurement results.

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 using a second detector. In this case, the second detector may be positioned at a pupil conjugate position of the subject's eye.

Also, for example, the second objective measurement means may be an objective measurement means that projects a non-patterned indicator as a measurement light beam onto the fundus of the subject's eye, and receives the reflected light beam from the fundus using a second detector. In this case, the control means may obtain 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 obtained based on the proportion 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).

The second objective measuring means will now 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 each be constructed using separate optical components, or may be constructed so that at least some of the optical components are shared.

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 test eye with measurement light beams emitted from the multiple measurement light sources. The multiple measurement light sources may each be controlled independently. For example, the on/off and light intensity adjustment of each measurement light source may be controlled independently. Furthermore, the multiple measurement light sources may be arranged separately from each other in at least three meridian directions based on the optical axis center. For example, by arranging measurement light sources in at least three meridian directions, ocular refractive power including spherical power, cylindrical power, astigmatic axis angle, etc. can be measured. Note that the meridian directions in which the measurement light sources are arranged may be any number of meridian directions (e.g., meridian 1, meridian 2, meridian 3, meridian 4, etc.). Furthermore, at least one measurement light source may be arranged in each meridian direction.

For example, the light projection optical system may include an objective optical system. The objective optical system irradiates the measurement light beams emitted from the multiple measurement light sources onto the fundus of the subject's eye. The objective optical system may have one or more optical elements for projecting the measurement light beams toward the subject's eye.

The light receiving optical system may be configured to include at least a detector. For example, the light receiving optical system receives the reflected light beam of the measurement light beam reflected by the fundus of the subject's eye with a detector (e.g., image sensor 122, image sensor 323).

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 the detector. The objective optical system may have one or more optical elements for guiding the reflected light beam by the fundus of the subject's eye to the detector.

In this embodiment, the first objective measurement means measures one of the examinee's eyes using a method other than the photorefraction method, and the second objective measurement means measures both of the examinee's eyes 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 ease of measurement (in other words, more difficult) than the second objective measurement means. Furthermore, the second objective measurement means has lower measurement accuracy but higher ease of measurement (in other words, easier) than the first measurement means. Therefore, the two measurement methods can be used according to the situation.

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

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

<Use as an objective measurement method>
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.

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. It is sufficient that the light projection optical system has at least a light source.

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 subject's eye or the light source for projecting an index light beam onto the anterior segment of the subject's eye may also serve as the measurement light source for projecting a measurement light beam onto 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 light sources for the first objective measurement means and the second objective measurement means.

The second objective measurement means arranges multiple measurement light sources in the meridian direction based on the center of the optical axis of the light-projecting optical system, and is able to obtain ocular refractive power based on the movement of light when each measurement light source is turned on in sequence. Therefore, it is preferable to use a light source that emits a point-like or line-like light beam as the light source for the light-projecting optical system in the first objective measurement means, so that the meridian direction can be identified.

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.

The detector of the anterior segment observation optical system provided in the first objective measurement means may also serve as the detector of the second objective measurement means. In other words, the detector for photographing the anterior segment of the subject's eye may also serve as a detector (second detector) for receiving the measurement light beam reflected by the fundus in photorefraction measurement of the subject's eye. This makes it possible to obtain ocular refractive power 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.

The eye examination device may be configured so that the first objective measurement means and the second objective measurement means share only the light source, or so that the detector is shared. Of course, it may also be configured so that both the light source and the detector are shared.

<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 a narrow range of the anterior segment of the subject's eye. 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.

The first alignment means must 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 the detection of the alignment index image may also be performed by an anterior segment observation optical system (e.g., anterior segment observation optical system 80) for photographing the anterior segment of the subject's eye. 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.

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, more precise (severe) alignment may be performed using the first alignment means than using the second alignment means.

<Second Alignment Means>
The eye examination apparatus may include a second alignment means for adjusting the positional relationship between the subject's eye and the second objective measurement means by photographing the subject's 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 subject's eye and the second objective measurement means by photographing the anterior segment of the subject's eye over a wider range. In this case, the working distance from the subject's eye to the second objective measurement means may be set longer than the working distance from the subject's eye to the first objective measurement means.

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., anterior segment observation optical system 80, 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 use an anterior segment observation image of the subject's eye to roughly adjust the relative position of the second objective measurement means with respect to the subject's eye. In other words, the second alignment means may be used to perform rougher alignment than the first alignment means.

<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.

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 measurement mode switching signal 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.

For example, the switching signal may be output by the examiner operating an operating means (e.g., operation unit 11, operation unit 210). As one example, the switching signal may be output by selecting a measurement mode. Also, for example, the switching signal may be output in accordance with a measurement program that automatically progresses measurement of the subject's eye. As one 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 measurement takes more than a predetermined time, etc.

In the above example, an eye examination device is shown equipped with a first objective measurement means and a second objective measurement means, but either of the objective measurement means may be provided as an attachment attached to the eye examination device. For example, the eye examination device may have the first objective measurement means, and the attachment may have the second objective measurement means. Of course, even in such a configuration, some of the two objective measurement means may be shared.

<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.

[Transformation optical system]
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 test eye using a photorefraction method. For example, by attaching the attachment, the conversion optical system is disposed in the optical path of the first objective optical system, and the conversion optical system is used as 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 test 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 test eye using a method other than the photorefraction method and the ocular refractive power of the test eye using the photorefraction method can be obtained.

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 angle of view of the objective optical system compared to when the attachment is not attached.

For example, the transformation optical system may include only multiple measurement light sources. In this case, the wide-angle lens may be removably inserted into the optical path of the first objective optical system. By adding the transformation optical system to the first objective optical system of the eye examination device using an attachment and then inserting a wide-angle lens into the optical path of the first objective optical system, the measurement method for the subject's eye can be easily converted.

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 device with multiple measurement light sources and adding wide-angle lenses as attachments, the measurement method for the subject's eye can be easily converted. As mentioned 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 device, or may be provided exclusively.

Furthermore, for example, the transformation optical system may include both multiple 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 for the subject's eye can be easily converted.

By arranging such a wide-angle lens, the photographing angle of view of the first objective optical system of the eye examination device can be switched between the photographing angle when measuring the ocular refractive power of the subject's eye using a method other than the photorefraction method and the photographing angle when measuring the ocular refractive power of the subject's eye using the photorefraction method. For example, with a method other than the photorefraction method, a narrower area of the subject's eye is photographed, improving measurement accuracy compared to the photorefraction method. Also, for example, with the photorefraction method, a wider area of the subject's eye is photographed, improving ease of measurement compared to the method other than the photorefraction method. The first objective optical system may include an anterior segment observation optical system, and the photographing angle of view of the anterior segment may be switched by arranging the wide-angle lens.

<Distance measuring means>
The attachment may include a distance measurement means (e.g., distance measurement unit 31) for measuring the distance from the subject's eye to the eye examination apparatus. For example, the distance measurement means may measure the distance from the subject's eye to the attachment, or the distance from the subject's eye to the housing (e.g., housing unit 20). Furthermore, for example, the distance measurement 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. The distance from the subject's eye to the eye examination apparatus may be expressed as the distance to a specific component of the eye 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.

The distance measurement means may be capable of measuring the distance between the subject's eye and the eye examination device. 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. In other words, 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. In other words, 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. In other words, the distance measurement means may be an ultrasonic detector. Of course, other optical systems and detectors may also be used.

It is preferable to use an ultrasonic detector as the distance measurement means. In this case, the distance measurement 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, when measuring the subject's eye using the photorefraction method, 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 easier to measure distance.

If the eye examination device is configured to be able to switch the measurement method for the eye refractive power of the subject's eye by attaching or detaching such an attachment to the eye examination device, the eye examination device may be provided with an attachment means, connection means, detection means, etc.

<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. Furthermore, 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, or may have a mechanism that combines at least one of a fitting mechanism, a connecting mechanism, and a different mechanism.

<Connection method>
The eye examination apparatus may include a connection means (e.g., an electrical connection portion 24) that electrically connects the eye examination apparatus to 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.

The connection means may be configured to establish an electrical connection in conjunction with the attachment of the attachment to the eye examination device. For example, it may be configured so that the terminals and terminal holes of the connector come into direct contact in conjunction with the attachment of the attachment. In this case, the connection means may have either the terminal or terminal hole structure, and the attachment may have the other structure.

The connection means may also 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 make indirect contact via a cable or the like. In this case, after the attachment is attached, connectors can be separately connected to the attachment and the connection means. Note that a cable may be fixed to the attachment and the cable's connector may be brought into contact with the connection means to electrically connect them. Of course, the cable may also be fixed to the connection means (in other words, the cable may be used as part of the connection means) and the cable's connector may be brought into contact with the attachment to electrically connect them.

<Detection means>
The eye examination apparatus may include a detection unit (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 unit is required to at least detect whether the attachment is in contact with the eye examination apparatus when attached. In this case, the detection unit may be a contact-type detector (e.g., a physical sensor), a non-contact detector (e.g., an optical sensor, a magnetic sensor), or the like. Furthermore, the detection unit is required to at least detect whether the eye examination apparatus and the attachment are electrically connected. In this case, the detection unit may be a non-contact detector (e.g., a current sensor, a voltage sensor, or the like).

<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 acquire 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 associated with the attachment attachment or detachment may be performed.

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 to change its operation when a detection signal is obtained indicating either the attachment of an attachment to the eye examination apparatus or the electrical connection between the eye examination apparatus and the attachment. Alternatively, the control means may control the eye examination apparatus to change its operation after detection signals are obtained indicating both the attachment of an attachment and the electrical connection.

For example, the control means may automatically switch modes 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 modes 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., display unit 22), a sound generating means (e.g., a speaker), a notification means (e.g., a lamp), etc.

The control means may output guidance information that guides the examiner to change the setting from the first measurement mode using the first objective optical system to the 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 in the next action. As an 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 to switch between the first measurement mode and the second measurement mode, ensure the working distance between the subject's eye and the eye examination device, etc. Of course, the guidance information may be a combination of these pieces of information, or may be information that is different from these pieces of information.

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.

In the eye examination device 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. As an 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. It 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. It may also be an optical system that measures the subject's eye to acquire the optical characteristics of the subject's eye, the ocular refractive power of the subject's eye, binocular vision function (amount of heterophoria, stereoscopic function, etc.), contrast sensitivity, etc.

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

For example, by attaching an attachment to such an eye examination device, it is possible to convert the first objective optical system, which objectively acquires information about the subject's eye, into a second objective optical system, which objectively measures the subject's eye's refractive power using a photorefraction method. Therefore, using a single eye examination device, it is possible to easily acquire information about the subject's eye and the subject's eye's refractive power measured using a photorefraction method.

In addition, in the eye examination device 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 also 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 piece of information, such as eye position information and interpupillary distance, of the subject's eye.

For example, by attaching an attachment having such an optical system to an eye examination device, it is possible to convert a first objective optical system for objectively obtaining 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, using a single eye examination device, it is possible to easily obtain 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.

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 device and the electrical connection between the ophthalmic examination device and the attachment. For example, the control means may automatically switch from a first mode in which imaging, inspection, measurement, etc. is performed using a first objective optical system to a second mode in which imaging, inspection, measurement, etc. is performed using a second objective optical system, or may output guidance information for changing settings.

Note that 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 can be supplied to a system or device via a network or various storage media, and the control device (e.g., a CPU) of the system or device can read and execute the program.

First Example
A first example of the eye examination apparatus according to this embodiment will be described.

<Device configuration>
1 and 2 are external views of an eye examination apparatus 1. Fig. 1 shows a state in which an attachment is attached to the eye examination apparatus 1. Fig. 2 shows a state in which the attachment is removed from the eye examination apparatus 1. Here, a handheld eye refractive power measuring device is taken as an example of the eye examination apparatus.

The eye examination device 1 includes a handle unit 10, a housing unit 20, an attachment unit 30, etc. The handle unit 10 has an operation unit 11, etc. The operation unit 11 is a button that inputs an operation signal to start measurement of the subject's eye E.

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

The attachment unit 30 has a distance measurement unit 31, a mounting 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 from a transparent material (e.g., a panel) such as acrylic resin or a glass plate.

In this embodiment, the attachment unit 30 is detachably attached to the housing unit 20. For example, the attachment units 23 and 32 are made of ferromagnetic material, are attached by their mutual magnetic force, and can be detached by applying a force greater than this magnetic force. Of course, the attachment units 23 and 32 may be attached using a structure other than ferromagnetic material (for example, a convex portion and a concave portion fitting together). They may also be attached using a combination of a ferromagnetic material and a structure other than ferromagnetic material.

The attachment unit 23 has an attachment detection unit 23a for detecting contact between the attachment unit 23 and the attachment unit 32. The attachment detection unit 23a may be a contact sensor (e.g., a microswitch, etc.) or a non-contact sensor (e.g., an optical sensor, a magnetic sensor, etc.). The output signal from the attachment detection unit 23a is input to the control unit 130. This detects that the attachment unit 30 is attached to the housing unit 20.

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; when connected to each other, the terminals and terminal holes come into contact, enabling the 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; electrical signals may be transmitted and received via a connection such as a USB cable (i.e., wired communication), or via Bluetooth (registered trademark) (i.e., wireless communication).

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 (e.g., a current sensor, a voltage sensor, etc.). The 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.

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 reflection light of the subject's eye E at the pupil.

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.

<First 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, and the like. 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.

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

[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 optically conjugate with the fundus. The opening of the hole mirror 53 is optically conjugate with the pupil. The prism 54 is disposed at a position that is not optically conjugate with the pupil, and decenters the light beam passing through the prism 54 with respect to the optical axis. The prism 54 is driven to rotate around the optical axis by a drive unit 54a. Note that instead of the prism 54, a parallel plane plate may be disposed obliquely on the optical axis.

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 optically conjugate with the fundus. The ring lens 58 is optically conjugate with the pupil. The image sensor 59 is optically conjugate with the fundus.

In this configuration of the first measurement optical system 50, the measurement light beam emitted from the light source 51 passes through the relay lens 52, hole mirror 53, prism 54, objective lens 42, and 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, causing the pupil projection image (projected light beam on the pupil) at the opening of the hole mirror 53 to rotate eccentrically at high speed. The measurement light beam is reflected by the fundus and reflected by the hole mirror 53 via the beam splitter 41, objective lens 42, and prism 54. The reflected light beam then passes through the relay lens 55 and is focused at the position of the light receiving aperture 56, where it is imaged as a ring-shaped image (ring image) on the image sensor 59 via the collimator lens 57 and ring lens 58. The output signal from the image sensor 59 is input to the control unit 130 via the image processing unit 59a, and the eye refractive power is calculated.

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 image sensor 59.

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 at the fundus using a Shack-Hartmann sensor. Also, for example, the first measurement optical system 50 may be a phase difference type optical system that projects a slit onto the subject's eye E.

[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., all 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 moves the light source 61 and the fixation target plate 62 in the optical axis direction, thereby fogging the subject's eye E. The drive unit 64 also moves the fixation target plate 62 in the optical axis direction, thereby moving the presentation position of the fixation target relative to the subject's eye E.

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

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.

The Z target projection optical system 70b comprises 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.

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 beams (approximately parallel beams). For example, multiple point light sources and collimator lenses are arranged at 45-degree intervals on concentric circles based on the optical axis, and symmetrically across a vertical plane passing through the optical axis.

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 across a vertical plane passing through the optical axis. The second target projection optical system can also be used for anterior segment illumination to illuminate the anterior segment of the subject's eye E, as a target for measuring the corneal shape of the subject's eye E, etc.

The Z index projection optical system 70b may be configured to project at least one of a point-shaped index, a ring-shaped index (such as a Mayer ring), a line-shaped index, etc.

[Anterior segment observation optical system]
The anterior eye 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 eye of the subject's eye E and receives a light beam reflected from the anterior eye. 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 eye 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.

<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.

[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.

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 concentric circles 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 serves to widen the angle of view for capturing an image of 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.

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

The measurement light source 111 and the wide-angle lens 121 are provided as an integrated component fixed to the base 101. Of course, the measurement light source 111 and the wide-angle lens 121 can also be provided as separate components. The measurement light source 111 has multiple measurement light sources, and each measurement light source is 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.).

This embodiment illustrates a case where the measurement light sources 111 are arranged in four meridian directions. This embodiment also illustrates a case where the measurement light sources 111 are arranged in order on a virtual straight line extending in the meridian directions with the optical axis center of the second measurement optical system 100 as the reference. In one meridian direction, two sets are arranged symmetrically with the optical axis center of the wide-angle lens 121 as the reference.

Eight sets of measurement light sources 111 (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, measurement light sources 111a to 111h are arranged at 45° intervals on a concentric circle outside the outer circumferential circle of wide-angle lens 121. Of course, each measurement light source may be arranged in any position.

Measurement light sources 111a to 111h each have 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 measurement light source 111a) are arranged sequentially at a predetermined interval in the meridian direction (in other words, the radial direction) based on the optical axis center of wide-angle lens 121. Each light source can be independently controlled by control unit 130. For example, each light source can be independently controlled to be turned on and off, and its light intensity can be adjusted.

Note that, although the above description has been given with reference to an example in which the measurement light sources 111 are arranged symmetrically with respect to the optical axis center of the second measurement optical system 100, this is not limiting. 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. Furthermore, while the above description uses eight sets of measurement light sources 111, this is not limiting. For example, any set (e.g., three, four, five, six, etc.) of measurement light sources 111 may be used. Furthermore, the above description uses three measurement light sources, each of which are the measurement light sources 111a to 111h, but this is not limiting. For example, any number of light sources (e.g., two, four, five, etc.) may be used.

<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 that 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.

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 the fundus of both the left and right eyes. 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, the position of the wide-angle lens 121 widens the angle of view of the anterior segment, so that 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.

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 projection optical system 105 of the second measurement optical system 100 may be used to illuminate the anterior segment. In other words, the measurement light source 111 may perform both the function of irradiating the test eye E with a measurement light beam and the function of illuminating the anterior segment. Of course, a separate light source dedicated to illuminating the anterior segment may also be provided.

<Control unit>
The control unit 130 includes a CPU (processor), RAM, ROM, etc. The CPU controls the operation 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).

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

Memory 131 is a non-transitory storage medium that can retain its stored contents even if the power supply is interrupted. For example, memory 131 can be a hard disk drive, flash ROM, USB memory, etc. Memory 131 may also store the ocular refractive power of the subject's eye E, etc.

<Control operation>
The control operation of the eye examination apparatus 1 will now be described.

The eye examination device 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.

<Measurement using a method different from the 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, shortening the working distance from the subject's eye E to the eye examination device 1, and acquiring a magnified anterior eye observation image of the subject's eye E (an image of a narrow range including the pupil). Furthermore, detailed alignment is performed to measure eye refractive power more accurately.

Figure 5 shows an example of the display unit 22 in the first measurement mode. The examiner grasps 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 the 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 produced by the XY target projection optical system 70a, the finite alignment target image (here, the Mayer ring image M2) and the infinity alignment target image M3 produced by the Z target projection optical system 70b, etc. are displayed on the display unit 22. In addition, a reticle LT indicating the coordinates of the optical axis of the first measurement unit 40, etc. is displayed on the display unit 22.

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 eye examination device 1 based on the output signal from the image sensor 82 and the output signal from a detection unit (not shown) that detects the two-dimensional position of the alignment target image M1. The control unit 130 also determines the misalignment in the Z direction between the subject's eye E and the main body (optical axis) of the eye examination device 1 based on the output signal from the image sensor 82, using changes in the image spacing of the Mayer ring image M2. The control unit 130 also increases or decreases the number of indicators G based on the amount of misalignment in the Z direction.

The examiner moves the main body of the eye examination device 1 in the X and Y directions to position the alignment target image M1 within the reticle LT. He also moves the main body of the eye examination device 1 in the Z direction to set the indicator G to a specified 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 eye examination device 1. The examiner then operates the operation unit 11. This starts measurement of the subject's eye E.

Based on the output signal from the operation unit 11, the control unit 130 turns on the light source 51 to irradiate the test eye E with a measurement light beam, and captures the light beam reflected from the fundus using 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 this ocular refractive power.

In this embodiment, the ocular refractive power of the subject's eye E can be objectively measured using a method other than the photorefraction method. For example, the above control operation can be performed sequentially for the left and right eyes to obtain the ocular refractive power of the left eye and the ocular refractive power of the right eye separately. 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.

<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.

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 is electrically connected to the electrical connection unit 24 of the housing unit 20, causing an output signal to be emitted from the connection detection unit 25. These electrical connections enable the control unit 130 to control each component of the attachment unit 30 in addition to each component of the housing unit 20.

Based on the output signal from the wearing detection unit 23a and the output signal from the connection detection unit 25, 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 using a method other than the photorefraction method to a second measurement mode in which the ocular refractive power of the subject's eye E is objectively measured using the photorefraction method. 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.

The control unit 130 executes control according to the second measurement mode. For example, in the second measurement mode, the eye examination device 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 eye examination device 1 is increased, and an anterior segment observation image (a wide area 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's refractive power.

Figure 6 shows an example of the display unit 22 in the second measurement mode. The examiner grasps 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 on 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, etc., is displayed on the display unit 22.

The examiner moves the main body of the eye examination device 1 in the X, Y, and Z directions to bring the left and right eyes within the imaging field of view. This completes the alignment between the subject's eye E and the main body of the eye examination device 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 alignment is complete by emitting a sound or displaying a message. The examiner then operates the operation unit 11. This starts measurement of the subject's eye E.

The control unit 130 uses the distance measurement unit 31 to acquire the distance from the subject's eye E to the attachment unit 30 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 this to the distance from the attachment unit 30 to the wide-angle lens 121 (a known value from the design) to determine the separation distance (measured distance) between the subject's eye E and the wide-angle lens 121.

In addition, based on the output signal from the operation unit 11, the control unit 130 turns on the measurement light source 111 to irradiate the test eye E with a measurement light beam, and captures an image of the reflected light beam from the fundus using the image sensor 122.

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 light source 111a1 of the measurement light source 111a. The other measurement light sources 111b to 111h, as well as light sources 111a2 and 111a3, are turned off. The output signal from the image sensor 122 when light source 111a1 is turned on is stored in memory 131 as a measurement image. After the control unit 130 acquires a measurement image with light source 111a1 turned on, it turns off 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 light source 111a2 turned on, it turns off light source 111a2 and turns on the next light source 111a3, and similarly acquires a measurement image.

After acquiring a measurement image using the three light sources in one set of measurement light source 111a, the control unit 130 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 in each set are turned on, are not limited to this and may be any order.

Figure 7 is a diagram illustrating the photorefraction method. The control unit 130 then 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 pupil diameter to the radial dimension of the bright crescent in the pupil of the anterior segment contained in each measurement image, and obtains the ocular refractive power using the following formula (see, for example, JP 2006-149501 A):

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

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

For example, assuming 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. In other words, the ocular refractive power A of the test eye E can be calculated using the following formula from the proportion R of the bright crescent measured under constant conditions.

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

The control unit 130 calculates spherical information (spherical power) in the meridian direction where the measurement light source 111a is located based on the measurement image captured when the measurement light source 111a is turned on. For example, the control unit 130 acquires spherical information based on at least one of the measurement images captured when the three light sources 111a1 to 111a3 are turned on. In this case, the average value of the spherical information for each light source may be acquired as the spherical information for 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 for the meridian direction of the measurement light source 111a.

The control unit 130 similarly calculates spherical information in the meridian direction for the other measurement light sources 111b to 111h. Once the control unit 130 has acquired spherical information in all meridian directions, it acquires the spherical power of the subject's eye E based on this spherical information. Furthermore, it acquires the cylindrical power and astigmatic axis angle of the subject's eye E based on the spherical power in the meridian direction (spherical power distribution).

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 both be obtained by performing analysis processing on the left and right eyes separately. Each ocular refractive power is displayed on the display unit 22 and stored in memory 131.

Second Example
A second embodiment of the eye examination apparatus according to the present invention will be described. Note that the same components in the first and second embodiments are designated by the same reference numerals and will not be described again.

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

The eye examination device 200 comprises a movable stage 201, an operation unit 210, a drive unit 220, a face support unit 230, a display unit 240, a distance measurement unit 250, a measurement unit 260, etc. The operation unit 210 has a button for inputting an operation signal to start measurement of the subject's eye E. The operation unit 210 also has a lever for inputting an operation signal to move the measurement unit 260 relative to the subject's eye E. The drive unit 220 moves the measurement unit 260 in the X, Y, and Z directions relative to the movable stage 201. The face support unit 230 supports the subject's face. For example, the face support unit 230 may have 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, etc. 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 using either a photorefraction method or a method other than the photorefraction method.

Figure 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 segment observation optical system 80, etc.

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, etc. The light-projecting optical system 310 has at least a measurement light source 311. Like the measurement light source 111 described above, the measurement light source 311 has eight sets of measurement light sources arranged in four meridian directions, each of which has 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, etc., 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 the reflected light beam from the anterior segment.

In this configuration of the second measurement optical system 300, 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. The output signal from the imaging element 323 is input to the control unit 130 and display unit 240 via the 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 it to image one eye of the subject's eye E, and the imaging element 323 has an imaging angle of view that allows it to image both eyes of the subject's eye E.

In this embodiment, the light receiving optical system 320 is positioned further back (away from the subject's eye) than the objective lens 43, but this is not limiting. For example, the light receiving optical system 320 may be positioned in front of the objective lens 43 (closer to the subject's eye). In this case, the optical path may be split by a half mirror or the like between the beam splitter 41 and the objective lens 42, and a wide-angle lens 321, imaging lens 322, imaging element 323, etc. may be positioned.

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

The eye examination device 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 display unit 240).

<Measurement using a method different from the 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.

The examiner instructs the subject to place their face against the face support unit 230 and fixate on the fixation target (fixation target plate 62). This causes the anterior segment of the subject's eye E and each alignment target image to be captured by the image sensor 82. The control unit 130 uses each alignment target image to detect the corneal apex position, and drives the drive unit 220 based on the deviations in the X, Y, and Z directions of the corneal apex position relative to the alignment reference position, thereby completing auto-alignment between the subject's eye E and the main body of the eye examination device 1.

The examiner also operates the operation unit 210 to begin 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, image sensor 59, etc., and analyzes and processes the ring image, similar to the first embodiment, to measure the ocular refractive power of the subject's eye E.

<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.

In the second embodiment, the wide-angle lens 321 is not positioned 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 measurements 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.

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 this position information to position the left and right eyes within the imaging field 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 device 200. The control unit 130 also uses the distance measurement unit 250 to obtain the distance from the subject's eye E to the measurement unit 260. Note that the separation distance (measured distance) between the subject's eye E and the wide-angle lens 321 can be determined by measuring the distance from the subject's eye E to the front of the measurement unit 260 and adding this to the distance from the measurement unit 260 to the wide-angle lens 321 (a known value from the design).

The examiner operates the operation unit 210 to begin measurement of the subject's eye E. Based on the output signal from the operation unit 210, the control unit 130 sequentially turns on the measurement light sources 311 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.

The eye examination apparatus 1 and eye examination apparatus 200 described above can be used to perform at least one of measurements using a first measurement mode that uses a method other than photorefraction, and measurements using a second measurement mode that uses photorefraction. When obtaining the ocular refractive power of the subject's eye E, the first measurement mode requires more accurate alignment of the main body of the eye examination apparatus 1 (housing unit 20 or measurement unit 260) with respect to the subject's eye E. On the other hand, the second measurement mode does not require precise alignment of the main body of the eye examination apparatus 1 (attachment unit 30 or measurement unit 260) 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, if proper alignment is not possible when using the first measurement mode, or if satisfactory measurement results of the subject's eye E cannot be obtained, simple measurement results can be obtained efficiently by switching to the second measurement mode.

As explained above, the attachment of this embodiment is attached to an eye examination device having a first objective optical system for objectively obtaining information about the subject's eye, and is equipped with a conversion optical system for converting the first objective optical system into a second objective optical system that objectively measures the subject's eye's ocular refractive power using a photorefraction method. This makes it possible to easily obtain information about the subject's eye and the subject's eye's ocular refractive power measured using a photorefraction method using a single eye examination device, and is capable of handling photography, measurement, examination, etc. according to various conditions of the subject's eye.

The transformation optical system of the attachment in this embodiment also includes at least one of a plurality of measurement light sources arranged in the meridian direction based on the center of the optical axis 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. This allows the objective optical system to be easily converted into a photorefraction optical system by attaching the attachment, making it possible to accommodate a variety of conditions for the subject's eye.

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 by providing a distance measurement unit, the eye refractive power can be obtained appropriately. Note that it is also possible to use the distance measurement unit provided in the eye examination device, but when the attachment is attached, it may be difficult to obtain results depending on the configuration of the distance measurement unit. For this reason, providing a distance measurement unit in the attachment makes it possible to more reliably determine the measurement distance.

In addition, in the attachment of this embodiment, the distance measurement unit includes an ultrasound transmitter that transmits ultrasound toward the test eye, and an ultrasound receiver that receives ultrasound reflected by the test eye. When using photorefraction measurements on the test eye, the imaging angle of view of the objective optical system is widened. For this reason, for example, in configurations that measure distance based on alignment target images or bright spot images projected onto the test eye, these images are captured small along with the test eye, making detection difficult. On the other hand, in configurations that use ultrasound, the transmission and reception of ultrasound is not affected by changes in the imaging angle of view of the objective optical system, making it easier to measure distance.

The eye examination device of this embodiment also includes a mounting section to which the attachment is attached, and a connection section that electrically connects the eye examination device and the attachment, and the attachment can be used by connecting it using the connection section. Therefore, in photorefraction measurements of the subject's eye, it is possible to easily control the irradiation of the measurement light beam from the light source and the imaging of the reflected light beam from the fundus of the subject's eye. As an example, it is possible to easily synchronize the lighting of each light source with the imaging by the detector.

In addition, the eye examination device of this embodiment detects at least one of the attachment of the attachment to the eye examination device and the electrical connection between the eye examination device and the attachment, and controls the operation of the eye examination device based on the detection signal. Depending on whether the attachment is attached or detached, the ocular refractive power of the subject's eye can be efficiently measured using either measurement method.

In addition, the eye examination device of this embodiment automatically switches modes from a first mode using a first objective optical system to a second mode using a 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.

In addition, in the eye examination device 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. In other words, the eye examination device can measure the ocular refractive power of the subject's eye using a method other than the photorefraction method, and by attaching an attachment, the ocular refractive power of the subject's eye can be measured using the photorefraction method. Therefore, it is possible to use different modes as appropriate, depending on, for example, the subject's age and the quality of the measurement results obtained using each measurement method.

The eye examination device of this embodiment also acquires the ocular refractive power by controlling at least one of a first objective measurement means 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 means for objectively measuring the ocular refractive power of the subject's eye using the photorefraction method. This makes it possible to acquire the ocular refractive power of the subject's eye in accordance with, for example, various situations. As an example, the ocular refractive power of the subject's eye can be acquired using an objective measurement means suited to the purpose, use, measurement accuracy, etc.

In addition, in the eye examination device 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, 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. Therefore, for example, the first objective measurement means requires stricter (severe) alignment than the second objective measurement means, but can improve measurement accuracy. Also, for example, the second objective measurement means has lower measurement accuracy than the first objective measurement means, but can obtain measurement results simply and efficiently. The second objective measurement means may also be used for screening of the examinee's eyes for refractive errors, etc.

In addition, in the eye examination apparatus of this embodiment, the first objective measurement means has a first detector that receives a measurement light beam reflected by the fundus of the subject's eye, and is positioned at a fundus conjugate position with the subject's eye. Furthermore, the second objective measurement means has a second detector that receives a measurement light beam reflected by the fundus of the subject's eye, and is positioned at a pupil conjugate position with 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 makes it possible to use the two measurement methods, for example, when measuring the ocular refractive power of the subject's eye, depending on the situation.

In addition, in the eye examination device 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 the reflected light beam from the fundus using the first detector, and obtains the eye 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 eye refractive power may be obtained 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), thereby enabling the eye refractive power of the subject's eye to be measured with high accuracy.

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

In addition, the eye examination device 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 measurement mode switching signal 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.

In addition, in the eye examination device of this embodiment, the first objective measurement means has an anterior eye imaging optical system that images the anterior eye, and the detector of the second objective measurement means also serves 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 having to provide a dedicated detector for each optical system.

<Example of transformation>
In the first embodiment, the attachment unit 30 is detachably attached to the handheld eye examination apparatus 1, 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 photorefraction, the optical system can be converted to photorefraction measurement by attaching the attachment unit 30.

In the first embodiment, an example was described in which the attachment unit 30 includes a measurement light source 111 and a wide-angle lens 121, but this is not limiting. For example, the attachment unit 30 may include only the measurement light source 111, and the wide-angle lens 121 may be provided inside the housing unit 20. Alternatively, for example, the attachment unit 30 may include only the wide-angle lens 121, and the measurement light source 111 may be provided inside the housing unit 20.

When the attachment unit 30 is equipped with only the measurement light source 111, the wide-angle lens 121 may be provided so that it can be inserted or removed in the optical path from the presentation window 21 to the image sensor 122. As an example, it may be provided near the objective lens 43, near the image sensor 81, etc. The control unit 130 may insert or remove the wide-angle lens 121 in conjunction with the attachment or removal of the attachment unit 30, the electrical connection of the attachment unit 30, the examiner's selection of the first measurement mode or the second measurement mode, etc., and may switch the imaging angle of view of the subject's eye E according to each measurement mode.

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

If 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 arranged 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.

In the second embodiment, a stationary eye examination device 200 is described as having a configuration including a first measurement optical system 50 and a second measurement optical system 300, but this is not limiting. Of course, a handheld eye examination device may also have a configuration including a first measurement optical system 50 and a second measurement optical system 300. In other words, a handheld eye examination device may be provided with both an optical system for objectively measuring the ocular refractive power of the subject's eye E using a method other than the photorefraction method, and an optical system for objectively measuring the ocular refractive power of the subject's eye E using the photorefraction method.

In the second embodiment, an example was described in which the measurement unit 260 includes the measurement light source 311 of the light projection optical system 310 and the wide-angle lens 321 and image sensor 323 of the light receiving optical system 320, but this is not limiting. 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 eye observation optical system 80 may also serve as the image sensor 323. Of course, the measurement light source 311 and wide-angle lens 321 may be provided as an integrated component, and this component may be inserted or removed in conjunction with each measurement mode.

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

In the first embodiment, when the light source of the index projection optical system 70 and the measurement light source 111 of the projection optical system 110 are both used as a light source, the light source settings may be changed depending on the measurement mode. Similarly, in the second embodiment, when the light source of the index projection optical system 70 and the measurement light source 311 of the projection optical system 310 are both used as a light source, the light source settings may be changed depending on the measurement mode. For example, the amount of light irradiated from the light source may be adjusted to an appropriate value.

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 this light source. In this case, the light source may be provided on the optical axis or near the optical axis. 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.

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 compared to the first measurement mode, making it impossible to see the fixation target plate 62. For this reason, as mentioned 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.) can also be inserted on the optical axis of the fixation target presenting optical system 60 to adjust it so that the fixation target plate 62 is visible.

In the second embodiment, too, depending on the position at which the wide-angle lens 321 is inserted, removed, or fixed, it may be impossible to see the fixation target plate 62. 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 also be flashing.

In the first embodiment, an example was given of a configuration in which one of two measurement modes, 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 this is not limiting. For example, guidance information may be output that guides the examiner to change 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 that instructs the examiner on the next operation, a message display that prompts 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 begin smoothly.

In the first and second embodiments, a configuration has been described in which the distance from the subject's eye E to the eye examination device is obtained by transmitting and receiving ultrasound using the distance measurement unit 31 or the distance measurement unit 250, but this is not limiting. 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 obtained 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 the change in imaging magnification due to the placement of the wide-angle lens 121. Furthermore, if the interpupillary distance of the subject's eye E has been acquired 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 imaging magnification due to the positioning of the wide-angle lens 121.

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 switched on and off depending on whether they are in the first measurement mode or the second measurement mode. However, this is not limiting. 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.

When aligning an eye examination device 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 finite distance can be detected. In photorefraction measurements 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 measurements.

In this way, the eye examination device 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 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 eye refractive power using a method other than the photorefraction method or the photorefraction method with a simple configuration, without having to provide a dedicated light source for each optical system.

In the first and second embodiments, a configuration was 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, this is not limited to this. For example, a configuration may be used 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 also makes it possible to obtain information in more meridian directions than the photorefraction method, thereby allowing the ocular refractive power of the subject's eye to be measured with high accuracy.

In the first and second embodiments, a configuration for acquiring the ocular refractive power of the subject's eye E in a 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, but this is not limiting. 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 for 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 this position information (coordinates) to determine 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 determine 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.

Regardless of the measurement mode of the subject's eye E, if the refractive power of the left eye and the refractive power of the right eye are obtained separately, the possibility of anisometropia may be determined based on the difference between these refractive powers.

In the first and second embodiments, the refractive power of the subject's eye E can be measured using at least one of a method other than the photorefraction method and the photorefraction method. Therefore, for example, if both measurement methods are performed on the subject's eye E, the first eye's refractive power measured using a method other than the photorefraction method and the second eye's refractive power measured using the photorefraction method may be output so that they can be compared. As an example, the first eye's refractive power and the second eye's 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.

REFERENCE SIGNS LIST 1 Handheld eye examination device 20 Housing unit 30 Attachment unit 50 First measurement optical system 90 Second measurement optical system 130 Control unit 200 Stationary eye examination device 260 Measurement unit 300 Second measurement optical system

Claims (6)

An eye examination device, comprising:
a first objective measuring means for objectively measuring the ocular refractive power of the subject's eye by a method different from the photorefraction method;
a second objective measuring means for objectively measuring the ocular refractive power of the subject's eye by the photorefraction method;
a control means for controlling at least one of the first objective measuring means and the second objective measuring means to obtain the ocular refractive power;
An eye examination device comprising: The eye examination apparatus of claim 1,
the first objective measuring means measures 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 different from the photorefraction method;
the second objective measuring means measures the ocular refractive power of both of the examinee's eyes by the photorefraction method by projecting a measurement light beam onto the fundus of the eye;
An eye examination device characterized by: The eye examination apparatus according to claim 1 or 2,
the first objective measurement means is an objective measurement means that projects 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 first detector, and the first detector is disposed at a position conjugate with the fundus of the subject's eye;
the second objective measurement means is an objective measurement means that projects 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, and the second detector is disposed at a pupil conjugate position of the subject's eye.
An eye examination device characterized by: In the eye examination apparatus according to any one of claims 1 to 3,
a first alignment means for photographing the subject's eye and adjusting the positional relationship between the subject's eye and the first objective measuring means;
a second alignment means for photographing the subject's eye at a wider angle than the first alignment means and adjusting the positional relationship between the subject's eye and the second objective measurement means;
An eye examination device comprising: In the eye examination apparatus according to any one of claims 1 to 4,
The eye examination apparatus is characterized in that the control means sets 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 of a measurement mode for measuring the ocular refractive power of the subject's eye. a first objective measuring means for objectively measuring the ocular refractive power of the subject's eye by a method different from the photorefraction method;
a second objective measuring means for objectively measuring the ocular refractive power of the subject's eye by the photorefraction method;
An eye examination program for use in an eye examination device comprising:
When executed by a processor of the eye examination device,
a control step of controlling at least one of the first objective measuring means and the second objective measuring means to obtain ocular refractive power;
An eye examination program that causes the eye examination device to execute the above.