JP2002345754A - Eye fatigue measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eye fatigue measuring device capable of objectively measuring the degree of fatigue of a subject eye. SOLUTION: This device comprises an image projecting means 12 for projecting an image to the subject eye; scanning mechanisms 12d and 12e for scanning the position of the image based on the subject image in the optical axial direction of the subject eye; a detecting means 11 for detecting the state change of the subject eye; and a control part 15 for making the scanning mechanisms perform a test scanning for scanning the position of the image, and determining the degree of fatigue of the subject eye on the basis of the state change detected by the detecting means at that time. Since the state of the subject eye is changed according to the degree of fatigue of the subject eye, the state change qualitatively and quantitatively shows the degree of fatigue of the subject eye. According to this visual fatigue measuring device, the degree of fatigue of the subject eye can be objectively measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eye fatigue measuring device for measuring the degree of fatigue of an eye to be examined.

[0002]

2. Description of the Related Art At present, in the information-oriented society, there is a tendency for eyes to be overworked due to near work on screens of televisions, personal computers and the like. For normal work, the eyes adjust accordingly to see various objects at various distances,
Repeat relaxation and tension of ciliary muscle.

[0003] However, overwork causes the eye to stop adjusting to continue looking at objects at the same distance,
The ciliary muscle remains tense. If the tension continues, the ciliary muscles become fatigued and their movements slowed down, resulting in improper adjustment. As a result, the object becomes less visible and causes various stresses. Further, if this fatigue is repeated for a long period of time, it leads to a decrease in visual acuity.

[0004]

Conventionally, regarding this eye fatigue, for example, "very tired"
It is only subjectively expressed as "slightly tired", there is no measuring device that measures objectively (qualitatively and quantitatively), and such a measuring method has not yet been established.

[0005] For this reason, even in the medical field, etc., the diagnosis of eye fatigue is based only on the symptoms that each person is aware of. It is difficult to take appropriate measures for each. Therefore, an object of the present invention is to provide an eye fatigue degree measuring device capable of objectively measuring the degree of fatigue of an eye to be examined.

[0006]

According to a first aspect of the present invention, there is provided an eye fatigue measuring apparatus for projecting an image to an eye to be inspected, and a position of the image with respect to the eye to be inspected. A scanning mechanism that scans in the optical axis direction, a detection unit that detects a change in the state of the eye to be inspected, and a test scan that scans the position of the image. A control unit for calculating the degree of fatigue of the subject's eye based on the change in state.

[0007] Since the state of the eye to be examined changes according to the degree of fatigue of the eye to be inspected, this state change indicates the degree of fatigue of the eye to be examined qualitatively and quantitatively. Therefore, according to the eye fatigue measurement device, the fatigue of the subject's eye is objectively measured.
According to a second aspect of the present invention, in the eye fatigue level measuring apparatus according to the first aspect, the control unit obtains the timing of the state change as an index of the fatigue level.

According to a third aspect of the present invention, in the eye fatigue level measuring apparatus according to the first aspect, the control section obtains a change rate of the state change as an index of the fatigue level. It is. According to a fourth aspect of the present invention, in the eye fatigue measuring apparatus according to any one of the first to third aspects, the detecting unit determines the state change of the subject's eye as the state change of the subject's eye. It detects changes in the refractive power of the optometry.

According to a fifth aspect of the present invention, there is provided the eye fatigue level measuring apparatus according to any one of the first to fourth aspects, wherein information is externally provided in response to an instruction from the control unit. Is further provided. Then, the control unit causes the display to display the obtained degree of fatigue.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> A first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, and 5. FIG. FIG. 1 is an external view of an eye fatigue measurement device 1 of the present embodiment (and an eye fatigue measurement device 2 of a second embodiment described later), and FIG. 2 is an eye fatigue measurement device 1 (and described later). It is a block diagram of the eye fatigue measuring device 2) of 2nd Embodiment.

As shown in FIG. 1, a cover 1a of the eye fatigue measuring device 1 has a measuring window 1b for allowing a measuring light (described later) to enter the eye to be examined, a display 16 for displaying information, and a start button. 17 and the like are arranged. The subject can measure the degree of eye fatigue by looking into the inside from the measurement window 1b while supporting the entire apparatus for measuring eye fatigue 1 like a video camera.

As shown in FIG. 2, the eye fatigue measuring apparatus 1 includes a refraction measuring section 11 (corresponding to a detecting means) and a projecting section 1.
2 (corresponding to image projection means), dichroic mirror 13, control unit 15 (corresponding to control unit), display 16
(Corresponding to a display), a start button 17 and the like. The projection unit 12 includes a viewing table 12a and a light source (visible light source).
12b, a convex lens 12c, a viewing table moving mechanism 12d, and a motor 12e are provided.

In the projection section 12, a convex lens 12c, a viewing table 12a, and a light source 12b are arranged in order from a side (closer) to the eye 10 to be inspected. The luminous flux from the visual table 12a illuminated by the light source 12b is converted into a state close to a parallel luminous flux by the convex lens 12c and then enters the subject's eye 10, so that when viewed from the subject's eye 10, the position of the visual table 12a is It appears to be farther than the location.

Of these, the viewing table 12a and the light source 12b are:
Both can be moved in the optical axis direction of the subject's eye 10 by the visual table moving mechanism 12d and the motor 12e (corresponding to the scanning mechanism) in a state in which the mutual positional relationship is unchanged.

The refraction measuring section 11 is described in, for example,
Such as a refractive power measuring apparatus described in Japanese Patent No. 35575, a refractive power measuring apparatus to which a radiographic method is applied. A chopper 11 having a slit formed therein
a, a motor 11i for rotating the chopper 11a, a light source (infrared light source) 11b for illuminating the chopper 11a, a lens 11d for projecting a stripe pattern formed by the chopper 11a onto the fundus of the eye 10, and a fundus of the eye 10 A light receiving unit 11h for detecting the moving speed of the stripe pattern formed by the returning light, optical systems 11f and 11g, and the like are provided (reference numeral 11).
f and 11c are lenses, 11e is a half mirror, and 11g is a diaphragm. ).

The dichroic mirror 13 guides measurement light (infrared light) emitted from the refraction measurement unit 11 and measurement light (visible light) emitted from the projection unit 12 to the eye 10 to be examined. In addition, the infrared light returning from the subject's eye 10 returns to the refraction measuring unit 11. Here, in the refraction measuring unit 11, since the chopper 11 a rotates, the stripe pattern projected on the fundus of the subject's eye 10 moves.
Then, the moving speed of the stripe pattern formed on the light receiving unit 11h changes according to the eye refractive power of the subject's eye 10. Therefore,
The change in the signal detected by the light receiving unit 11h indicates a change in the eye refractive power of the subject's eye 10.

The refraction measuring section 11 of the present embodiment only needs to be able to measure at least one change in the eye refractive power in the radial direction among the eye refractive powers of the eye 10 to be inspected.
The moving direction of the stripe pattern formed by 1a may be at least one direction, and the moving speed detected by the light receiving unit 11h may be at least the moving speed in one direction corresponding to the moving direction.

The control unit 15 includes a CPU and a circuit having a memory used for its operation. The control unit 15 refers to signals output from the start button 17 and the light receiving unit 11h, and refers to the light sources 12b, 11b, It drives and controls the motors 12e, 11i and the display 16, and performs calculations.

Specifically, the control unit 15 controls the driving of the motor 12e while driving the light source 12b, thereby scanning the layout and position of the visual table 12a (the visual table 12a and the light source 12b). The control unit 15 drives the light source 11b, the motor 11i, and the light receiving unit 11h while driving the light receiving unit 1b.
By referring to the output of 1h, a change in the eye refractive power of the eye 10 to be inspected is detected (this change in the eye refractive power can be detected at a relatively short period of about 0.2 seconds). ).

FIG. 3 is an operation flowchart executed by the control unit 15. The control unit 15 includes a start button 17
When recognizing that has been pressed (step S1YES), placing Mihyo 12a in position D ₀₀ (step S2).
This predetermined position D ₀₀ is positioned sufficiently proximal relative to the subject's eye 10, for example, a position corresponding to the remote location of 30cm when viewed from the eye 10 (Note that the remote location, placed there It is about 3.33 Dp (diopter) when represented by the eye refraction necessary to image the imaged object.)

Next, the position of the visual table 12a is rapidly scanned far away, and the change in the refractive power of the eye 10 at that time is monitored (step S3). The timing of the monitoring may be intermittent or continuous as long as the period is sufficiently shorter than the scanning speed of the visual table 12a. Here, FIG. 4A is a diagram showing a change in the position of the visual table 12a in step S3, and FIG.
FIG. 3 is a diagram showing a change in the eye refractive power in No. 3;

Since the eye 10 to be examined adjusts as the position of the visual table 12a is scanned, the eye refractive power also changes accordingly. If the ciliary muscle of the eye 10 to be examined is not tired, the eye refractive power changes at substantially the same timing as when the position of the visual table 12a changes.

On the other hand, when the ciliary muscle of the eye 10 to be examined is tired, the movement of the ciliary muscle is slowed down. It is later than the changing timing. The delay time (hereinafter referred to as “follow-up delay”) becomes longer as the degree of fatigue becomes higher.

Therefore, in the present embodiment, the following delay is obtained as an index of the degree of fatigue of the eye 10 to be examined. That is, in step S4, the tracking delay Δt, that is, the timing at which the position of the visual table 12a is scanned as an index of the degree of fatigue of the subject's eye 10 (for example, a time t ₀ intermediate the scanning start time and the scanning end time) (T ₁ −t ₀ ) between the time at which the eye refractive power changes and the time at which the eye refractive power changes (for example, a time t ₁ between the change start time and the change end time).

In the next step S5, step S5
The index of the degree of fatigue calculated in 4 is displayed on the display 16. Here, the content to be displayed may be the value of the following delay Δt itself, but the degree of the fatigue is high if the value of the following delay Δt is high and the degree of the fatigue is low if the value of the following delay Δt is large. Is difficult for ordinary users to understand intuitively.

Therefore, it is assumed that the control unit 15 of the present embodiment stores in advance a stage table as shown in FIG. 5 in the memory. In this stage table, the following delay Δt is calculated for each of the ranges in which the value is included, for each of several levels of fatigue (for example, “none”, “low”, “medium”, “high”) in an intuitive expression. It corresponds to.

For example, the following delay Δt is in the range of 0 to 0.3.
, It corresponds to the degree of fatigue “none”, and the range 0.
When included in 3 to 0.5, it corresponds to the fatigue level "low",
When included in the range 0.5 to 1, the degree of fatigue corresponds to “medium”, and when included in the range 1 to 1, corresponds to the degree of fatigue “high” (the unit of the numerical value is seconds (sec)).

In step S5, the control unit 15 first determines what range the tracking delay Δt is in, recognizes the corresponding fatigue level in this stage table, and displays the stage on the display unit 16. Instruct to display.
For example, when the value of the follow-up delay Δt is 1.2, the display 16 includes the range 1 to “5. The fatigue level is high.” Is displayed, and the value of the follow-up delay Δt is 0.1. 2
When it is 1, since it is included in the range 0 to 0.3, a display such as "No fatigue degree" is displayed.

As described above, according to the present embodiment, the position of the visual table 12a is scanned, and the tracking delay Δt of the eye 10 at that time is measured. The following delay Δt is
It is an index that qualitatively and quantitatively indicates the degree of fatigue of the subject's eye 10 because it is measured based on the eye refractive power that reliably indicates the state of the subject's eye 10 and changes according to the fatigue of the subject's eye 10. .

That is, according to the eye fatigue measuring device 1 of the present embodiment, the degree of fatigue of the subject's eye can be objectively measured. Further, in the present embodiment, the measured degree of fatigue is displayed on the display 16, so that the user can check the displayed content and take appropriate measures for the eye to be examined.
Also, the subject can keep an eye health by referring to the displayed contents.

Moreover, in the present embodiment, intuitive expressions (“none”, “low”, “medium”,
Since “high” is adopted, even a user who does not fully understand the physical meaning of the following delay Δt can easily understand the degree of fatigue. <Second Embodiment> A second embodiment of the present invention will be described with reference to FIG. 1, FIG. 2, FIG. 6, FIG. 7, and FIG. Here, only differences from the first embodiment will be described, and other descriptions will be omitted.

The appearance of the eye fatigue measurement device 2 of the present embodiment is similar to that of the eye fatigue measurement device 1 of the first embodiment.
For example, as shown in FIG. The configuration of the eye fatigue measurement device 2 of the present embodiment is the same as that of the eye fatigue measurement device 1 of the first embodiment except that the control unit 25 is provided instead of the control unit 15. The control unit 25 includes, similarly to the control unit 15, a circuit including a CPU and a memory used for the operation thereof, and includes a start button 17, a light receiving unit 11h
, The light source 12b and the motor 12
e, and control and drive the display 16.

FIG. 6 is an operation flowchart executed by the control unit 25. In FIG. 6, the same steps as those shown in FIG. 3 are denoted by the same reference numerals. The operation flowchart executed by the control unit 25 of the present embodiment is the same as the operation flowchart shown in FIG. 3 except that steps S24 and S25 are inserted instead of steps S4 and S5.

First, at step S24, step S4
Similar to (see FIG. 3), an index of the degree of fatigue of the eye 10 is calculated, but the index is different. Here, FIG.
(A) is a figure which shows the change of the position of the visual table 12a in step S3, and FIG. 7 (b) is a figure which shows the change of the eye refractive power in step S3. If the ciliary muscle of the eye 10 to be examined is not tired, the eye refractive power is determined by using the eye chart 12
The speed changes at a speed substantially the same as the speed at which the position a changes.

On the other hand, when the ciliary muscle of the subject's eye 10 is tired, the movement of the ciliary muscle becomes slow, and the speed at which the eye refractive power changes depends on the position of the visual table 12a. Slower than changing speed. The higher the degree of fatigue, the lower the speed at which the eye refractive power changes (hereinafter, referred to as “follow-up speed”).

Therefore, in the present embodiment, the following speed is obtained as an index of the degree of fatigue of the eye 10 to be examined. That is, in step S24, as an index of the degree of fatigue of the eye 10, the following speed α, that is, the period Δt ′ from the change start time to the change end time of the eye refractive power, and the eye refractive power during the period Δt ′ The ratio to the change amount ΔD (ΔD / Δ
t ′) is calculated.

In the next step S25, the indicator of the degree of fatigue calculated in step S24 is displayed on the display 16. Here, the content to be displayed is the following speed α
Can be intuitively understood by ordinary users as to how much the value of the following speed α is high and how low is the degree of fatigue. difficult.

Therefore, it is assumed that the control unit 25 of the present embodiment stores in advance a stage table as shown in FIG. 8 in the memory. This stage table shows the following speed α in several levels of intuitive expression in terms of the degree of fatigue (for example,
"None", "low", "medium", "high").

For example, when the following speed α is included in the range 0 to 3, the degree of fatigue corresponds to “high”. When the following speed α is included in the range 3 to 6, the degree of fatigue corresponds to “medium”. Corresponds to a low degree of fatigue, and corresponds to "none" when included in the range 10 (the unit of the numerical value is Dp / sec). The control unit 25 in step S25 first determines what range the follow-up speed α is in, recognizes the corresponding fatigue level in this stage table, and displays the stage on the display 16. To instruct.

For example, when the value of the following speed α is 1.2, the indicator 16 is included in the range of 0 to 3, so that “Fatigue is high” is displayed, and the following speed α is displayed.
When the value of is 4, it is included in the range 3 to 6, and the display such as "the degree of fatigue is medium." As described above, according to the present embodiment, the position of the visual table 12a is scanned, and the tracking speed α of the eye 10 at that time is measured.

The following speed α is measured on the basis of the eye refractive power that reliably indicates the state of the eye 10 to be examined.
Since it changes in accordance with the degree of fatigue of the eye to be inspected 10, it is an index indicating the degree of fatigue of the eye to be inspected qualitatively and quantitatively. That is, according to the eye fatigue measurement device 2 of the present embodiment, the fatigue of the subject's eye can be objectively measured.

Further, in the present embodiment, the measured degree of fatigue is displayed on the display 16, so that the user can confirm the displayed content and take appropriate measures for the eye to be examined. Also, the subject can keep an eye health by referring to the displayed contents. Moreover, in this embodiment,
The content of the display includes intuitive expressions ("none", "low",
Since “medium” and “high” are employed, even a user who does not fully understand the physical meaning of the following speed α can easily understand the degree of fatigue.

<Others> In each of the above embodiments,
Although the number of steps of the degree of fatigue is set to 4, it may be set to a number other than 4. For example, six levels such as “none”, “low”, “slightly low”, “medium”, “slightly high”, and “high” may be used. The refraction measuring unit 11 in the first embodiment (or the second embodiment) is described in
As in the refractive power measurement device described in Japanese Patent No. 35575, the configuration is such that the eye refractive power in two directions perpendicular to each other can be detected, and the control unit 15 (or the control unit 25) is configured as shown in FIG.
In addition to executing the operation flowchart shown in FIG. 6 (or FIG. 6), an operation flowchart for measuring the spherical power, astigmatic power, and the like (measurement and displaying the measurement result) may be executed. With such a configuration, an apparatus that can perform both the measurement of the degree of fatigue of the eye 10 and the measurement of the refractive power of the eye 10 is easily realized.

In other words, a device capable of measuring the degree of fatigue of the eye 10 can be easily realized by only partially changing the conventional refractive power measuring device. In each of the above embodiments, the direction of movement of the visual table 12a performed by the control unit in step S3 is a direction from the near point side to the far point side. The direction may be on the point side.

In each of the above-described embodiments, the control unit scans the position of the visual table 12a only once when measuring the degree of fatigue (that is, when executing step S2 and subsequent steps), and detects the scan once. Reference is made to changes in the eye refractive power, and the characteristics of the eye 10 to be obtained as a result (eye to be examined 1
The scanning pattern (combination of the scanning start position, the scanning end position, and the scanning speed) in step S3 may be configured in accordance with the far point of 0 or the like.

Further, in each of the above embodiments, a method of actually moving the visual table is used to scan the apparent position of the visual table. However, if the apparent position is scanned, Any other method, such as moving the optical system instead of the visual table, may be employed. Further, any one of the eye fatigue degree measuring apparatuses of the above embodiments may be connected to a head mounted display (HMD) (for example,
7-333552).

In the case of mounting on a head-mounted display, the position (apparent position) of a display image displayed by the head-mounted display may be scanned instead of scanning the visual table.

[0049]

As described above, according to the present invention,
An eye fatigue measurement device capable of objectively measuring the fatigue of an eye to be examined is realized.

[Brief description of the drawings]

FIG. 1 is an external view of an eye fatigue measurement device 1 according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an eye fatigue measurement device 1 according to an embodiment of the present invention.

FIG. 3 is an operation flowchart executed by a control unit 15 of the first embodiment.

FIG. 4A is a view 1 in step S3 of FIG. 3;
FIG. 2B is a diagram showing a change in the position of 2a, and FIG. 2B is a diagram showing a change in the eye refractive power in step S3.

FIG. 5 is a diagram illustrating a stage table stored in a control unit 15 of the first embodiment.

FIG. 6 is an operation flowchart executed by a control unit 25 of the second embodiment.

FIG. 7A is a view 1 in step S3 of FIG. 6;
FIG. 2B is a diagram showing a change in the position of 2a, and FIG. 2B is a diagram showing a change in the eye refractive power in step S3.

FIG. 8 is a diagram illustrating a stage table stored in a control unit 25 according to the second embodiment.

[Explanation of symbols]

 1, 2, 3 Eye fatigue measurement device 1a, 2a, 3a Cover 1b Measurement window 10 Eye to be examined 11 Refraction measurement unit 11a Chopper 11b, 12b Light source 11c, 11d Lens 11g Aperture 11h Light receiving unit 11i, 12e Motor 12 Projection unit 12a Table 12c Convex lens 12d Look-up table moving mechanism 13 Dichroic mirror 15, 25, 35 Control unit 16 Display 17 Start button

Claims (5)

[Claims] An image projection unit configured to project an image on an eye to be inspected; a scanning mechanism for scanning a position of the image with respect to the eye to be inspected in an optical axis direction of the eye to be inspected; And a control unit for causing the scanning mechanism to perform a test scan for scanning the position of the image, and for obtaining a degree of fatigue of the eye to be examined based on a state change detected by the detection unit at that time. An eye fatigue measurement device comprising: 2. The eye fatigue measurement apparatus according to claim 1, wherein the control unit obtains the timing of the state change as an index of the fatigue degree. 3. The eye fatigue measurement device according to claim 1, wherein the control unit obtains a change rate of the state change as an index of the fatigue degree. 4. The eye fatigue measurement device according to claim 1, wherein the detecting unit detects a change in the refractive power of the eye as the state change of the eye. An eye fatigue degree measuring apparatus characterized in that: 5. The eye fatigue measurement device according to claim 1, further comprising: a display for externally displaying information in response to an instruction from the control unit, wherein the control is performed. An eye fatigue level measuring device, wherein the unit displays the determined degree of fatigue on the display.