JP7406413B2 - ophthalmology equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ophthalmological device.

In general, eye strain occurs when you stare at a monitor display such as a television, personal computer, tablet terminal, or smartphone for a long time. In addition, among young people, acute esotropia and other problems caused by looking at the screens of smartphones and game consoles at close range for long periods of time are becoming a problem. Here, since there is a close relationship between eye fatigue and the convergence function of the eyes, it is effective to understand the convergence function state of the eyes in order to estimate eye fatigue.

On the other hand, conventionally, the difference in the amount of light incident on the left and right eyes to be examined is intentionally changed, and the specific difference in the amount of light that causes a change in the line of sight between the left and right eyes to be examined is used as a visual indicator for eye fatigue. 2. Description of the Related Art A testing device that objectively tests eye fatigue is known (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2017-169601

However, in the conventional examination apparatus, it is necessary to provide a mechanism within the apparatus for changing the difference in the amount of light incident on the left and right eyes to be examined, respectively, which has led to the problem that the apparatus becomes complicated and large.

The present invention has been made in view of the above problem, and an object of the present invention is to provide an ophthalmologic apparatus that can easily grasp the convergence functional state of an eye to be examined while suppressing the increase in size of the apparatus.

In order to achieve the above object, the ophthalmologic apparatus of the present invention includes: an optotype projection system that presents an optotype to a subject; an optotype control unit that controls the presentation state of the optotype by the optotype projection system; a fusion time measurement unit that measures the fusion time from when the subject simultaneously views the optotype with the left and right eyes until double vision appears; and a result output unit that outputs the result in association with the image time.

With the ophthalmological apparatus configured in this manner, it is possible to easily grasp the convergence functional state of the eye to be examined while suppressing the increase in size of the apparatus.

1 is a perspective view showing the appearance of the ophthalmologic apparatus of Example 1. FIG. FIG. 2 is an explanatory diagram schematically showing the configuration of a measurement unit of the ophthalmologic apparatus of Example 1. FIG. FIG. 2 is an explanatory diagram schematically showing the configuration of the measurement optical system of the ophthalmological apparatus of Example 1, in which (a) shows a state where both eyes are looking at infinity, and (b) shows a state where both eyes are looking at a predetermined position. Indicates the state in which FIG. 2 is a block diagram showing the configuration of a control system of the ophthalmologic apparatus of Example 1. FIG. 3 is an example of a graph showing the relationship between the intensity of the fusion stimulus, the examination distance, and the fusion time obtained by the ophthalmological apparatus of Example 1. FIG. It is an example of the graph which shows the relationship between inspection distance and fusion time. It is an example of the graph which shows the relationship between the intensity|strength of a fusion stimulus, and a fusion time. It is an example of a table showing the relationship between the intensity of fusion stimulation, inspection distance, and fusion time.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the ophthalmologic apparatus of this invention is demonstrated based on Example 1 shown in drawing.

(Example 1)
Hereinafter, the configuration of the ophthalmologic apparatus 10 of Example 1 will be explained based on FIGS. 1 to 5.

The ophthalmologic apparatus 10 of the first embodiment is a binocular open type ophthalmologic apparatus that can simultaneously measure the ocular characteristics of the subject's eyes with both eyes open.

As shown in FIG. 1, the ophthalmologic apparatus 10 of Example 1 includes a base 11 installed on the floor, an optometry table 12, a support 13, an arm 14, and a measurement unit 20. . The ophthalmologic apparatus 10 also includes an examiner controller 19a such as a mobile terminal, a subject controller 19b (see FIG. 4), and a display device 19c such as a liquid crystal display.

In this ophthalmological apparatus 10, the eye characteristics of the subject's eye are measured while the subject is directly facing the optometry table 12 and has his or her forehead in contact with the forehead rest 15 provided in the measurement unit 20. Hereinafter, when viewed from the subject, the left-right direction is the X direction, the up-down direction (vertical direction) is the Y direction, and the direction perpendicular to the X and Y directions (depth direction) is the Z direction.

The optometry table 12 is supported by the base 11, and its height position is adjustable. The support column 13 stands upright in the Y direction from the rear end of the optometry table 12, and has an arm 14 provided at the top. The arm 14 suspends and supports the measurement unit 20 above the optometry table 12, and extends from the support 13 along the Z direction. This arm 14 is attached to the support column 13 so that it can move up and down.

A control box 30a is provided below the optometry table 12, in which a main control unit 30 that integrally controls each part of the ophthalmologic apparatus 10 is housed. Note that power is supplied to the main control unit 30 from a commercial power source (not shown) via a power cable 30b.

The measurement unit 20 performs arbitrary subjective tests and arbitrary objective measurements. In the subjective test, an optotype or the like is presented to the subject, and a test result is obtained based on the subject's response to the optotype or the like. This subjective test includes subjective refraction measurements such as a distance test, a near test, a contrast test, and a glare test, a visual field test, an astigmatic axis test, and an astigmatic power test. Furthermore, in objective measurement, the eye to be examined is irradiated with light, and information (characteristics) regarding the eye to be examined is measured based on the detection result of the returned light. This objective measurement includes measurement for acquiring the characteristics of the eye to be examined and photography for acquiring an image of the eye to be examined. Furthermore, objective measurements include objective refraction measurement (reflex measurement), corneal topography measurement (keratometry), intraocular pressure measurement, fundus photography, and optical coherence tomography (hereinafter referred to as "OCT"). There are tomography (OCT) and measurements using OCT.

Further, this measurement unit 20 is connected to a main control section 30 via a control/power cable 30c (see FIG. 2), and power is supplied via this main control section 30. Information is also transmitted and received between the measurement unit 20 and the main control section 30 via this control/power cable 30c.

As shown in FIG. 2, the measurement unit 20 includes a mounting base portion 20a, a left drive mechanism 21L and a right drive mechanism 21R provided on the mounting base portion 20a, and a left eye measurement head supported by the left drive mechanism 21L. 22L, and a right eye measurement head 22R supported by a right drive mechanism 21R.

The left eye measurement head 22L and the right eye measurement head 22R are configured to be plane symmetrical with respect to a vertical plane located between them in the X direction. Furthermore, the structure of each drive part of the left drive mechanism 21L that supports the left eye measurement head 22L and the structure of each drive part of the right drive mechanism 21R that supports the right eye measurement head 22R are located between the two in the X direction. It has a planar symmetrical configuration with respect to the vertical plane in which it is located.

The left drive mechanism 21L is attached to one end of the mounting base section 20a, and controls the positions of the left eye measurement head 22L in the X direction, Y direction, and Z direction, and the left direction based on control commands from the main control section 30. The orientation of the eye EL to be examined about the eyeball rotation axis OL (see FIG. 2) is changed. The left drive mechanism 21L includes a left vertical drive section 23a, a left horizontal drive section 23b, and a left rotation drive section 23c. These drive units 23a, 23b, and 23c are arranged between the mounting base unit 20a and the left eye measurement head 22L in this order from above: left vertical drive unit 23a, left horizontal drive unit 23b, and left rotation drive unit 23c. has been done.

The right drive mechanism 21R is attached to the other end of the mounting base portion 20a, and controls the positions of the right eye measurement head 22R in the X direction, Y direction, and Z direction, and the right The orientation of the eye ER to be examined about the eyeball rotation axis OR (see FIG. 2) is changed. The right drive mechanism 21R includes a right vertical drive section 24a, a right horizontal drive section 24b, and a right rotation drive section 24c. These drive units 24a, 24b, and 24c are arranged between the mounting base unit 20a and the right eye measurement head 22R in this order from above: right vertical drive unit 24a, right horizontal drive unit 24b, and right rotation drive unit 24c. has been done.

Here, the left vertical drive section 23a, the left horizontal drive section 23b, the right vertical drive section 24a, and the right horizontal drive section 24b all include an actuator that generates driving force such as a pulse motor, a plurality of gear sets, a rack and・It has a transmission mechanism such as a pinion that transmits driving force. Note that the left horizontal drive section 23b and the right horizontal drive section 24b may be provided with separate combinations of actuators and transmission mechanisms in the X direction and the Z direction. In this case, the configuration can be simplified and the horizontal direction Movement can be easily controlled.

Further, the left rotation drive unit 23c and the right rotation drive unit 24c also include an actuator such as a pulse motor that generates a driving force, and a transmission mechanism that transmits the driving force such as a plurality of gear sets or a rack and pinion. are doing. Here, the left rotation driving section 23c and the right rotation driving section 24c move the transmission mechanism that receives the driving force from the actuator along an arcuate guide groove centered on the eyeball rotation axes OL and OR. The left eye measurement head 22L and the right eye measurement head 22R can be rotated about the eyeball rotation axis OL of the left eye EL to be examined and the eyeball rotation axis OR of the right eye ER to be examined, respectively.

Note that the left rotation drive unit 23c and the right rotation drive unit 24c may be configured to rotatably attach the left eye measurement head 22L and the right eye measurement head 22R around their own rotation axes.

By rotating the left eye measurement head 22L and the right eye measurement head 22R in a desired direction by the left rotation drive unit 23c and the right rotation drive unit 24c, a divergence movement or a convergence movement is performed in the left and right examined eyes EL and ER. can be set. Thereby, the ophthalmological apparatus 10 can perform a test of divergence motion and convergence motion, and perform a distance vision test and a near vision test in a binocular viewing state to measure various characteristics of both eyes to be examined.

As shown in FIGS. 2 and 3, the left eye measurement head 22L includes a left eye measurement optical system 25L built in a left housing 22a fixed to a left rotation drive unit 23c, an objective lens 26L, and a left housing 22a. It has a left eye deflection member 27L provided on the outer surface. In this left eye measurement head 22L, the output light emitted from the left eye measurement optical system 25L via the objective lens 26L is bent by the left eye deflection member 27L and irradiated onto the left eye EL to measure the left eye characteristics. Measure.

As shown in FIGS. 2 and 3, the right eye measurement head 22R includes a right eye measurement optical system 25R built in a right housing 22b fixed to a right rotation drive unit 24c, an objective lens 26R, and a right housing 22b. It has a right eye deflection member 27R provided on the outer surface. In this right eye measurement head 22R, the output light emitted from the right eye measurement optical system 25R via the objective lens 26R is bent by the right eye deflection member 27R and irradiated onto the right eye to be examined ER to measure the right eye characteristics. Measure.

Hereinafter, an example of the configuration of the left eye measurement optical system 25L and the right eye measurement optical system 25R will be described with reference to FIGS. 3(a) and 3(b). Note that since the configuration of the left eye measurement optical system 25L and the configuration of the right eye measurement optical system 25R are the same, only the right eye measurement optical system 25R will be described below.

As shown in FIGS. 3A and 3B, the right eye measurement optical system 25R includes optical systems such as an observation system 25a (image acquisition section) and an optotype projection system 25b. Inside the right housing 22b, a light source, optical element (optical member, optical device), actuator, mechanism, circuit, display device, light receiving element, image sensor, etc. necessary for each optical system are provided.

Here, the observation system 25a is an optical system that photographs the anterior segment of the right subject's eye ER. By displaying the image taken by the observation system 25a (hereinafter referred to as "anterior segment image") on the display device 19c of the examiner controller 19a, it is possible for the examiner to confirm the state of the right eye ER. . Furthermore, it is possible to obtain alignment information in the directions (XY directions) orthogonal to the optical axis based on the anterior segment image, and to estimate the fusion state when viewing with both eyes.

The optotype projection system 25b is an optical system that presents an optotype to the right eye to be examined ER. The visual target projection system 25b includes a display capable of displaying any image, a moving lens, and the like. The display is composed of an EL (electroluminescence) or liquid crystal display, and in addition to landscape charts that use fixation and fog when performing objective and subjective tests, it also displays arbitrary optometry images such as Landolt rings and E letter optotypes. Display marks, etc. The moving lens is disposed between the display and the objective lens 26R, and is driven forward and backward along the optical axis. By moving the movable lens toward the objective lens 26R side, the refractive power can be displaced to the minus side, and by moving the movable lens toward the display side, the refractive power can be displaced to the plus side. Therefore, in the optotype projection system 25b, the apparent distance (hereinafter referred to as "examination distance") from the left and right eyes to be examined EL, ER to the presentation position of the optotype displayed on the display is determined as the movable lens moves forward and backward. Can be changed.

Further, when the optotype is being presented by the optotype projection system 25b, the ophthalmologic apparatus 10 of the first embodiment adjusts the rotational postures of the left eye measurement head 22L and the right eye measurement head 22R, and As shown, by making the optical axis LL from the left eye to be examined EL to the left eye deflection member 27L parallel to the optical axis LR from the right eye to be examined ER to the right eye deflection member 27R. , can be the visual axis when the subject is looking at infinity with both eyes. Further, as shown in FIG. 3(b), the rotational postures of the left eye measurement head 22L and the right eye measurement head 22R are adjusted so that the extended ends of the optical axis LL and the optical axis LR are directed toward a predetermined position P. By doing so, it is possible to set the visual axis in a state in which the subject is looking at the position P with both eyes. That is, in the ophthalmological apparatus 10, by simultaneously changing the rotational postures of the left eye measurement head 22L and the right eye measurement head 22R symmetrically, the visual axes of the left and right eyes EL and ER are changed to converge or diverge. , the visual axis can be directed to the position where the visual target is presented (for example, position P).

Furthermore, the left eye measurement optical system 25L and the right eye measurement optical system 25R may include an alignment detection system, a measurement system, and the like. The alignment detection system is an optical system that acquires alignment information in the optical axis direction (Z direction) and XY direction alignment information of the left eye measurement optical system 25L and the right eye measurement optical system 25R. The measurement system is an optical system that irradiates the eye to be examined with a light flux for measuring the eye characteristics of the eye to be examined and receives reflected light to obtain the eye characteristics.

As shown in FIG. 4, the main control unit 30 includes a left eye measurement optical system 25L, a right eye measurement optical system 25R, left and right vertical drive units 23a and 24a as left and right drive mechanisms 21L and 21R, and a left and right horizontal drive unit 23b. 24b, left and right rotation drive units 23c and 24c, an examiner controller 19a, a subject controller 19b, and a storage unit 30d are connected.

Here, the examiner controller 19a is an operating mechanism used by the examiner to operate the ophthalmologic apparatus 10. The examiner controller 19a is communicably connected to the main control unit 30 by short-range wireless communication. Although the examiner controller 19a in the first embodiment uses a mobile terminal such as a tablet terminal or a smartphone, it may be connected to the main control unit 30 via a wired or wireless communication path. The configuration is not limited to 1. That is, the examiner controller 19a may be a notebook personal computer, a desktop personal computer, or the like, and may be configured to be fixed to the ophthalmologic apparatus 10.

The examiner controller 19a is also provided with a display device 19c. The display device 19c includes a display surface 19d (see FIG. 1, etc.) on which images and the like are displayed, and a touch panel type input section 19e disposed to overlap the display surface 19d. The examiner controller 19a, under the control of the main control unit 30, displays the anterior segment image etc. from the observation system 25a on the display surface 19d as appropriate. Further, the examiner controller 19a outputs operation information such as alignment instructions and measurement instructions input via the input section 19e to the main control section 30.

The subject controller 19b is used to input the subject's responses when acquiring various eye characteristics of the left and right subject eyes EL and ER. Although not shown, the subject controller 19b may be any input device such as a control lever, keyboard, mouse, or mobile terminal. The subject controller 19b is connected to the main control unit 30 via a wired or wireless communication path.

The main control unit 30 deploys a program stored in a connected storage unit 30d or a built-in internal memory 30e on, for example, a RAM (Random Access Memory), thereby controlling the examiner controller 19a and the examinee controller 19b as appropriate. The operation of the ophthalmologic apparatus 10 is controlled in accordance with the operations performed on the ophthalmologic apparatus. In the first embodiment, the storage unit 30d is configured with a ROM (Read Only Memory), an EEPROM (Electrically Erasable Programmable ROM), etc., and the internal memory 30e is configured with a RAM or the like.

Further, the main control section 30 of the first embodiment includes an optotype control section 31, a visual axis calculation section 32, a fusion time measurement section 33, and a result output section 34.

The optotype control unit 31 controls the optotype projection system 25b to set the presentation state of the optotype to be presented to the subject to an arbitrary state. Here, the "optotype presentation state" set to an arbitrary state by the optotype control unit 31 is defined by the inspection distance that defines the apparent position of the optotype and the ease of fusion of the presented optotype. This is the intensity of the fusion stimulus that defines the intensity. That is, the optotype control unit 31 drives the movable lenses of the optotype projection system 25b of the left-eye measurement optical system 25L and the optotype projection system 25b of the right-eye measurement optical system 25R forward and backward, and sets the examination distance to an arbitrary value. (for example, 10 cm, 20 cm, 30 cm, etc.). Further, at this time, the visual target control unit 31 adjusts the rotational postures of the left eye measurement head 22L and the right eye measurement head 22R, and directs the visual axes to a position separated by the test distance from the left and right eyes EL and ER. Furthermore, the optotype control unit 31 controls the optotypes displayed on the display of the optotype projection system 25b, and applies the fusion stimulation of the optotypes displayed on the left and right optotype projection systems 25b to an appropriate intensity (for example, fusion). Set to a high intensity that makes it easy to image, a low intensity that makes it difficult to fuse images, etc.). Note that the set values for the examination distance and the intensity of the fusion stimulus may be set by the examiner via the examiner controller 19a, or may be programmed in advance.

The visual axis calculation unit 32 calculates the left eye to be examined EL and the right eye to be examined based on the positions of the pupil centers of the left eye to be examined EL and the right eye to be examined ER, and the positions of the corneal reflections of the left eye to be examined EL and the right eye to be examined ER. Find the visual axis of ER. Here, the position of the pupil center is detected from the anterior segment images of the left eye EL and the right eye ER taken by the observation system 25a. Further, the position of the corneal reflection is detected based on a bright spot obtained when the parallel light beam irradiated onto the left eye EL or the right eye ER forms an image inside the left eye EL or the right eye ER.

The fusion time measurement unit 33 measures the fusion time from when the subject starts viewing the optotypes presented by the optotype projection system 25b to when double vision appears. Note that "simultaneous viewing" is a state in which the left eye EL and the right eye ER are simultaneously viewing the presented optotype. Furthermore, "diplopia" is a condition in which a person sees double visual targets when viewing with both eyes. In other words, the "fusion time" is the time from when the left subject eye EL and right subject eye ER start viewing the optotype simultaneously until the optotype seen with both eyes appears double.

Further, here, the test distance and the intensity of the fusion stimulus are set as appropriate for the optotype presented to the subject. Therefore, the fusion time measurement unit 33 measures the fusion time for each optotype having a different inspection distance or intensity of fusion stimulation.

Further, the fusion time measuring section 33 measures the fusion time based on the response result of the subject inputted via the subject controller 19b. In other words, the fusion time measuring unit 33 estimates the timing of double vision based on the response results input at the timing when it was determined that the subject had double vision. Then, the time from the start of presentation of the optotype to the time when it is estimated that double vision has occurred is counted as the fusion time.

The fusion time measurement unit 33 uses the left and right examined eyes EL photographed by the observation system 25a, the direction of the line of sight obtained from the anterior segment image of ER, the left and right examined eyes EL calculated by the visual axis calculation unit 32, The fusion time may be measured based on the direction of the visual axis of the ER. In other words, the timing of double vision is defined as when the direction of the line of sight of the left and right eyes EL and ER obtained from the anterior segment images and the direction of the visual axes of the left and right eyes EL and ER change more than a predetermined value. Good too.

The result output unit 34 outputs the presentation state of the optotype presented to the subject and the fusion time when the optotype is presented in association with each other. Specifically, the relationship between the inspection distance, the intensity of the fusion stimulus, and the fusion time is graphed as shown in FIG. 5 and displayed on the display surface 19d of the display device 19c.

Hereinafter, the effects of the ophthalmologic apparatus 10 of Example 1 will be explained.

In general, there is a close relationship between eye fatigue and the convergence functional state of the eyes, and it has been found that it is effective to understand the convergence functional state of the eyes in order to estimate eye fatigue. On the other hand, when a visual target presented at a relatively short distance (for example, 10cm to 50cm in front of the subject's eye) is viewed binocularly, a state in which fusion occurs is a condition in which the left and right eyes are brought inward (convergence). This is a state in which the eye's convergence function is functioning properly. On the other hand, when the convergence function of the eyes does not function properly, the left and right eyes cannot be brought inward for a long period of time, and the fusion time tends to become short. Therefore, since the fusion time can serve as an optotype indicating the convergence functional state of the eye, the convergence functional state of the eye can be grasped by measuring the fusion time.

Furthermore, when estimating eye fatigue based on the difference in the amount of light incident on the left and right eyes to be examined and changes in the direction of the line of sight, it is necessary to intentionally change the difference in the amount of light incident on the eyes to be examined. It cannot be said that eye fatigue is estimated. However, when determining the convergence function state of the eye based on the fusion time, it is possible to determine the convergence function state when an object is naturally viewed with both eyes, so eye fatigue can be reduced under natural conditions. It becomes possible to estimate. Furthermore, since the fusion time can be measured by simply counting the time, complicated analysis, calculation, complicated equipment, etc. are not required. As a result, it is possible to easily grasp the convergence functional state of the eyes while suppressing the increase in size of the device.

In contrast, in the ophthalmological apparatus 10 of Example 1, the optotype is presented to the left and right eyes EL and ER of the subject with both eyes open, and the time period during which the subject was able to fuse the optotype is (fusion time).

That is, first, the main control section 30 aligns the measurement unit 20 with respect to the left and right eyes EL and ER. Specifically, the left drive mechanism 21L is controlled to substantially match the optical axis of the left eye measurement optical system 25L built in the left eye measurement head 22L with the corneal apex of the left eye EL, and the right drive mechanism 21R is controlled. is controlled so that the optical axis of the right eye measuring optical system 25R built in the right eye measuring head 22R and the corneal vertex of the right eye to be examined ER are substantially aligned.

When the alignment by the main control unit 30 is completed, the optotype control unit 31 controls the optotype projection system 25b to set the left and right eyes EL, ER at a predetermined examination distance (for example, A visual target of a fusion stimulus of a predetermined intensity (for example, strong intensity) is presented at an apparent position 10 cm apart. At this time, the optotype control unit 31 adjusts the rotational postures of the left eye measurement head 22L and the right eye measurement head 22R so that the test subject can observe the test distance (for example, 10 cm) from the left and right eyes EL and ER with binocular vision. The visual axis is the same as when looking at an apparent position that is a distance away.

After the optotype is presented by the optotype projection system 25b, the fusion time measuring unit 33 estimates the timing at which diplopia appears based on the subject's response. Then, the fusion time from when the subject views the optotype binocularly until diplopia appears is measured.

When the measurement of the fusion time by the fusion time measurement section 33 is completed, the result output section 34 associates the measured fusion time with the presentation state of the optotype (inspection distance and intensity of the fusion stimulus) and internally calculates the fusion time. It is stored in the memory 30e.

Subsequently, the optotype control unit 31 controls the optotype projection system 25b to change the examination distance (for example, to 20 cm) and present the optotype to the left and right eyes EL and ER. At this time, the fusion stimulus is not changed. After presenting the optotype, the fusion time measurement section 33 measures the fusion time, and the result output section 34 associates the fusion time with the presentation state of the optotype (inspection distance and intensity of fusion stimulation). and stored in the internal memory 30e.

Then, visual targets with different examination distances and fusion stimulation strengths are sequentially presented, and the fusion time is repeatedly measured each time. When the measurement of the fusion time for each preset examination distance and fusion stimulus intensity is completed, the result output unit 34 outputs the fusion time and visual target presentation state (examination distance and fusion stimulus) stored in the internal memory 30e. (stimulus intensity) is graphed (see FIG. 5) and displayed on the display surface 19d of the display device 19c.

As described above, in the ophthalmological apparatus 10 of Example 1, the optotype is presented by setting the optotype presentation state (examination distance and intensity of fusion stimulus) to an arbitrary state, and the presented optotype is displayed with both eyes. Measure the fusion time after viewing. Then, the measured fusion time and the display state of the optotype (inspection distance and intensity of fusion stimulation) are displayed in association with each other. Therefore, it is possible to easily grasp the convergence functional state of the eye while eliminating the need for complex analysis, calculation, complicated equipment, etc., and suppressing the increase in the size of the equipment. For example, the examiner can visually check the graph displayed on the display surface 19d of the display device 19c (see FIG. 5) to determine the fusion time and the display state of the optotype (examination distance and intensity of the fusion stimulus). Based on this relationship, it is possible to estimate the degree of eye fatigue of the left and right eyes EL and ER.

Note that the degree of eye fatigue estimated based on the relationship between the display state of the optotype and the fusion time may be determined by, for example, an experiment and stored in the storage unit 30d. In this case, the result output unit 34 outputs "the degree of eye fatigue estimated based on the relationship between the display state of the optotype and the fusion time" stored in the storage unit 30d, the measured fusion time, and the time. The degree of eye fatigue of the left and right eyes EL and ER can be automatically determined by comparing the presentation state of the optotypes. In other words, the estimation of eye fatigue can be automated, and the degree of eye fatigue can be estimated more easily.

Additionally, in general, the fusion time tends to be longer if the person is younger, and the fusion time tends to be shorter as the person gets older. In other words, even with the same examination distance and the same fusion stimulus intensity, differences in fusion time occur depending on age, regardless of the state of eye fatigue.

On the other hand, in Example 1, the presentation state of the optotype is set to the test distance and the intensity of the fusion stimulus, and a plurality of optotypes with different test distances and fusion stimulus strengths are presented, and the test distance and the fusion stimulus intensity are different. The fusion time is measured for each visual target with different image stimulus intensities. In this way, the presentation state of the optotype can be changed in multiple stages, and the fusion time can be measured for each presentation state of a plurality of optotypes. As a result, the degree of eye fatigue can be appropriately estimated regardless of age-related differences in fusion time.

Moreover, in this first embodiment, the presentation state of the optotype is the examination distance and the intensity of the fusion stimulus. Therefore, the convergence functional state of the eyes can be accurately grasped.

Further, in the first embodiment, the result output unit 34 graphs the relationship between the fusion time and the display state of the optotype (inspection distance and intensity of the fusion stimulus) and displays the relationship on the display device 19c. Therefore, the examiner can easily recognize the relationship between the fusion time and the display state of the optotype (examination distance and intensity of the fusion stimulus), and can quickly estimate eye fatigue.

Furthermore, the fusion time measuring unit 33 of the first embodiment estimates the timing at which double vision appears based on the response of the subject, and measures the fusion time. However, the fusion time measurement unit 33 may detect the timing at which double vision appears based on the direction of the line of sight obtained from the anterior segment image or the direction of the visual axis calculated by the visual axis calculation unit 32. That is, the fusion time measurement unit 33 may measure the fusion time based on the anterior segment image or the visual axis. In this case, the fusion time from when the optotypes are viewed simultaneously until the appearance of diplopia can be objectively measured without being influenced by the subject's subjectivity. Therefore, the fusion time can be measured more accurately than when measuring the fusion time based on the response of the subject.

Although the ophthalmologic apparatus of the present invention has been described above based on Example 1, the specific configuration is not limited to this example, and the gist of the invention according to each claim. Changes and additions to the design are permitted as long as they do not deviate from the guidelines.

For example, in the first embodiment, an example is shown in which the presentation state of the optotype set to an arbitrary state by the optotype control unit 31 is the examination distance and the intensity of the fusion stimulation of the optotype. However, it is not limited to this. For example, the visual target presentation state may be such that only the test distance is set to an arbitrary state. In this case, a plurality of optotypes with different examination distances are sequentially presented to the subject without changing the intensity of the fusion stimulus, and the fusion time is measured each time the optotype is presented. Then, as shown in FIG. 6, the inspection distance and the fusion time are displayed in association with each other by graphing the relationship.

Alternatively, the visual target presentation state may be such that only the intensity of the fusion stimulus is set to an arbitrary state. In this case, without changing the examination distance, multiple optotypes with different fusion stimulus intensities are sequentially presented to the subject, and the fusion time is measured each time a target with a different fusion stimulus intensity is presented. do. Then, as shown in FIG. 7, the intensity of the fusion stimulus and the fusion time are displayed in association with each other by graphing the relationship.

In this way, the convergence functional state of the left and right eyes EL and ER can be adjusted even when only the examination distance or the intensity of the fusion stimulus is set as the presentation state of the optotype set to an arbitrary state. , it is possible to easily understand while suppressing the increase in the size of the device.

In addition, in Example 1, an example was shown in which the relationship between the fusion time and the display state of the optotype (inspection distance and intensity of the fusion stimulus) was displayed in a graph. You don't have to. For example, as in the table shown in FIG. 8, the relationship between the fusion time and the display state of the optotype (inspection distance and intensity of the fusion stimulus) may be shown in a list to be associated and displayed.

Furthermore, in Example 1, an example was shown in which a plurality of optotypes with different display states (inspection distance and intensity of fusion stimulus) were presented, and the fusion time was measured each time each optotype was presented. . However, it is not limited to this. For example, the presentation state of the optotype is set to a predetermined state, the optotype is presented, and the fusion time at that time is measured. Then, the convergence functional state of the left and right eyes EL and ER may be grasped based on the fusion time in a predetermined optotype presentation state. In other words, the presentation state of the visual target does not necessarily have to be changed step by step.

10 Ophthalmological apparatus 20 Measurement unit 21L Left drive mechanism 21R Right drive mechanism 22L Left eye measurement head 22R Right eye measurement head 25L Left eye measurement optical system 25R Right eye measurement optical system 25a Observation system 25b Target projection system 30 Main control unit 31 Visual Target control section 32 Visual axis calculation section 33 Fusion time measurement section 34 Result output section

Claims (7)

an optotype projection system that presents an optotype to a subject;
an optotype control unit that controls a presentation state of the optotype by the optotype projection system;
a fusion time measurement unit that measures the fusion time from when the subject simultaneously views the optotype with the left and right eyes until double vision appears;
a result output unit that associates and outputs the presentation state of the optotype and the fusion time;
An ophthalmological device comprising: The ophthalmological device according to claim 1,
The presentation state of the optotype is a test distance that is a distance from the left eye to be examined and the right eye to be examined to the presentation position of the optotype,
The optotype control unit displays a plurality of optotypes having different inspection distances,
The fusion time measurement unit measures the fusion time for each optotype having a different inspection distance,
The ophthalmological apparatus is characterized in that the result output unit outputs the examination distance and the fusion time in association with each other. The ophthalmological device according to claim 1,
The presentation state of the optotype is the intensity of the fusion stimulus of the optotype,
The optotype control unit causes a plurality of optotypes having different intensities of the fusion stimulus to be presented,
The fusion time measurement unit measures the fusion time for each optotype with a different intensity of the fusion stimulus,
The ophthalmologic apparatus is characterized in that the result output unit outputs the intensity of the fusion stimulus and the fusion time in association with each other. The ophthalmological device according to claim 1,
The presentation state of the optotype is defined as the intensity of the fusion stimulus of the optotype, and the test distance that is the distance from the left subject eye and the right subject eye to the presentation position of the optotype,
The optotype control unit displays a plurality of optotypes with different intensities of the fusion stimulus and different inspection distances,
The fusion time measurement unit measures the fusion time for each optotype having a different intensity of the fusion stimulus and the inspection distance,
The ophthalmologic apparatus is characterized in that the result output unit outputs the intensity of the fusion stimulus, the examination distance, and the fusion time in association with each other. The ophthalmological device according to any one of claims 1 to 4,
The ophthalmologic apparatus is characterized in that the result output unit outputs a graph of a relationship between the fusion time and the presentation state of the optotype associated with the fusion time. The ophthalmological device according to any one of claims 1 to 5,
comprising an image acquisition unit that acquires an anterior segment image of the left subject eye and an anterior segment image of the right subject eye;
The fusion time measuring unit measures the fusion time based on the anterior segment image of the left subject's eye and the anterior segment image of the right subject's eye acquired by the image acquiring unit. Ophthalmology equipment. The ophthalmological device according to any one of claims 1 to 5,
comprising a visual axis calculation unit that calculates a visual axis of the left eye to be examined and a visual axis of the right eye to be examined,
The ophthalmological apparatus, wherein the fusion time measurement unit measures the fusion time based on the visual axis of the left eye to be examined and the visual axis of the right eye to be examined, which are calculated by the visual axis calculation unit.