JP2001275968A - Visual acuity tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a visual acuity tester with which detailed assessment can be accurately and simply conducted. SOLUTION: The visual acuity tester, which examines the visual acuity of a subject by presenting an optotype, has an optotype presenting means for selectively presenting one of plurality of prepared optotypes which are contrast targets expressed as geometric series and which are at the stage of the same visual acuity, an input means for inputting the results of the subject response to the presented targets, a storage means for storing a program determining in regular sequence the optotype to be presented next based on the correction of errors for the response to the presented optotypes, a target presentation controlling means for controlling the optotype presenting means according to the program, and a calculation means for obtaining the visual acuity value of the subject from the right answer rate of the response at the stage of a given visual acuity value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual acuity test apparatus used by an ophthalmologist or the like.

[0002]

2. Description of the Related Art There is known a visual acuity inspection apparatus which presents a plurality of visual targets having different visual acuity values to a subject and obtains the visual acuity of the subject based on whether or not the visual targets can be determined. Conventionally, this kind of visual acuity testing apparatus generally performs a visual acuity test using a visual target using fractional visual acuity.

[0003]

However, the visual targets expressed in decimal visual acuity differ from each other in the size of the visual targets at each visual acuity stage, and accurate evaluation cannot be performed. That is, in the case of fractional visual acuity, when the visual acuity is improved from 0.2 to 0.3 and when the visual acuity is improved from 0.9 to 1.0, the visual acuity is improved by one step. However, when expressed as a visual angle, 0.2 to 0.3 is equivalent to 1.5 times, whereas from 0.9 to 1.0, 1 / 0.9 =
Since it is about 1.1 times, it is difficult to make the same evaluation.

[0004] In the determination of the visual acuity value, when there are five optotypes having the same visual acuity value, the visual acuity value is determined from the stage where three or more correct answers can be obtained. It was not enough to confirm the effect.

The present invention has been made in view of the above-mentioned problems of the prior art,
It is an object of the present invention to provide a visual acuity inspection apparatus that can easily perform more accurate and detailed evaluation.

[0006]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) In a visual acuity testing apparatus for presenting a visual target and inspecting the visual acuity of a subject, a plurality of contrasting visual targets represented by geometric series and having the same visual acuity value level are prepared. Optotype presenting means for selectively presenting one of the optotypes, and input means for inputting a response result of the subject to the presented optotype,
Storage means for storing a program for sequentially determining a target to be presented next based on the correctness of a response to the presented target, target presentation control means for controlling the target presenting means in accordance with the program, Calculating means for calculating the visual acuity value of the subject from the correct answer rate of the response.

(2) In the visual acuity test apparatus of (1),
The program includes a step of presenting all optotypes belonging to a first visual acuity level for which a majority of correct answers are obtained and all optotypes belonging to a second visual acuity level higher than the first visual acuity level. Wherein the calculating means calculates a visual acuity value from a correct answer rate in the first and second visual acuity value stages.

(3) In the visual acuity test apparatus of (2),
The program may further include presenting all the targets belonging to the second visual acuity value stage after presenting all the targets belonging to the first visual acuity value stage.

(4) In the visual acuity test apparatus of (2),
The program presents a target at the previous second visual acuity value stage when a majority of correct answers at the first visual acuity value stage is obtained, and provides a majority of correct answers at a visual target presentation at the second visual acuity value stage. When there is no visual target, the method further includes the step of presenting the remaining visual targets belonging to the first visual acuity value stage again.

(5) In the visual acuity test apparatus of (1),
Further comprising a display means for displaying the visual acuity value obtained by the calculation means, and a switching means for mutually switching the visual acuity value displayed on the display means between a logarithmic visual acuity value format and a minority visual acuity value format. Characteristic visual acuity testing device.

(6) In the visual acuity test apparatus of (1),
The input means is means for the examiner to obtain a response result of the subject and input the correctness thereof.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing an outline of an eyesight inspection apparatus according to the present invention.

Reference numeral 1 denotes a main body of the apparatus. A window 2 made of a glass plate provided with an antireflection film is arranged on the upper front part, and a subject looks at a target through the window 2 at the center. The window 2 may be provided with a filter instead of a glass plate. The inside of the apparatus main body 1 is painted black, making the internal structure difficult to see.

Reference numeral 3 denotes a power switch, and reference numeral 3a denotes a display lamp for notifying that the power is turned on by lighting. Reference numeral 4 denotes a transmission / reception window for transmitting / receiving an optical signal to / from a wireless remote controller 40 described later.

Next, an optical system disposed inside the apparatus main body 1 will be described with reference to FIGS. FIG. 2 shows the apparatus body 1
3 is a perspective view of the optical system when viewed from the right side, and FIG. 3 is a perspective view of the optical system when viewed from the front.

E indicates an eye to be examined. Reference numeral 20 denotes a disk-shaped optotype disc plate made of a glass plate, and a large number of optotype test optotypes such as visual acuity value optotypes are formed on the same circumference by chromium vapor deposition or the like. The optotype disc board 20 is rotated by the optotype disc board motor 21 to switch and arrange the optotypes to be presented to the subject. Reference numeral 22 denotes a mask plate for masking a part of the presented target, which is rotated by a mask plate motor 23, and applies a required mask to the target. Details of the target disc plate 20 and the mask plate 22 will be described later.

Reference numeral 24 denotes an illumination lamp for illuminating the test target,
25 is a mirror, 26 is a beam splitter, and 27 is a concave mirror. The concave mirror 27 in this embodiment is configured so that when the distance between the eye to be inspected and the window 2 of the visual acuity apparatus main body 1 is 0.9 m, the optical distance between the optotype and the eye to be inspected E is 5 m. The focal length is designed.

The luminous flux of the test target illuminated by the illumination lamp 24 is reflected upward by the mirror 25, passes through the beam splitter 26, and is reflected by the concave mirror 27. The target light flux reflected by the concave mirror 27 is reflected by the beam splitter 26 and travels to the eye E through the window 2. The beam splitter 26 is attached to a rotating shaft 28, and when the rotating shaft 28 is rotated by the motor 29, the inclination angle of the beam splitter 26 is changed. This allows
The optical path in the vertical direction of the optotype light beam reflected by the beam splitter 26 is changed, and the optotype light beam can be guided according to the height position of the eye to be inspected.

Reference numeral 30 denotes a detection optical system for detecting the height position of the eye to be inspected.
2 is provided inside the left and right sides of the window 2. The infrared light emitted from the light emitting unit of the remote controller 40 described later is
The light is condensed on the position detecting element 32 by the condensing lens 31, and the height position of the eye to be inspected is detected by the output signal from the position detecting element 32. (The method of adjusting the optical path of the target light to the height of the eye to be inspected is as follows. See JP-A-7-236612 for details.

Next, the details of the target disc plate 20 will be described with reference to FIG.

The optotypes such as the Landolt's ring used in the conventional visual acuity apparatus and the like are displayed in decimal acuity values, but the optotypes used in the present embodiment usually use the visual angle of the minimum separation threshold. Logarithmic (contrast visual acuity expressed in geometric series logari
thm of the minimum angle of resolution LogMAR
And ).

Conventional decimal visual acuity values are 0.1, 0.2-0.
As represented by 8, 0.9, 1.0, etc., the level of the visual acuity value changes by a decimal number of 0.1. For this reason, the case where the visual acuity is improved from 0.2 to 0.3 and the case where the visual acuity is improved from 0.9 to 1.0 are both one-stage visual acuity improvement. However, when expressed in terms of visual angle, the former corresponds to 1.5 times the visual angle, whereas the latter corresponds to 1.0 / 0.9 = 1.1.
Since it is equivalent to 1 time, it is hard to say that eyesight evaluation is always performed fairly.

The LogMAR target used in this embodiment is:
The logarithmic visual acuity value of the Landolt ring corresponding to the decimal visual acuity value of 1.0 is set to 0, and the logarithmic visual acuity value of -0.3 to +1.4 is set to 0.1.
It is formed in steps. As a result, the steps (change amounts) of the visual acuity values are at the same interval (same amount). On the other hand, the visual acuity value display of the visual target by the LogMAR is a value converted to a decimal visual acuity value so that the subject can easily understand.

As shown in FIG. 4, 13 landmark ring charts 50 of LogMAR are provided on the target disk 20.
A total of 24 chart portions are provided on the same circumference, with five Hiragana chart portions 51 of LogMAR and seven chart surfaces 52 used for red / green inspection, binocular balance, and the like. These chart sections are switched to the illumination light path of the illumination lamp 24 and presented as one screen in the window 2.

The details of the Landolt ring chart section 50 are shown in FIG.
Will be described. In FIG. 6, small optotypes (Landolt rings with a decimal visual acuity value of 0.25 to 2.0) are illustrated in an enlarged manner for convenience of explanation.

The chart portions 50a and 50b are both Landolt rings having a decimal visual acuity value of 0.04 (logarithmic visual acuity value +1.4), and the chart portions 50c and 50d are each having a decimal visual acuity value of 0.05.
One Landolt ring of (logarithmic visual acuity value +1.3) is formed one by one. The Landolt rings formed in the chart sections 50a to 50d are respectively selected from up, down, left, and right directions so that the cut directions do not overlap in these four charts.

The chart section 50e has a decimal visual acuity value of 0.063.
Two Landolt rings of (logarithmic visual acuity value +1.2) are formed side by side. The chart section 50f has a decimal visual acuity value of 0.
Two Landolt rings of 08 (logarithmic visual acuity value +1.1) are formed side by side similarly to the chart section 50e. In addition, a total of 4 formed in these chart portions 50e and 50f
The two Landolt rings are selected from up, down, left, and right directions so that the cut directions do not overlap.

The chart portions 50g to 50i have decimal visual acuity values of 0.1 (log visual acuity value + 1.0) and 0.125, respectively.
(Log visual acuity value +0.9), 0.16 (log visual acuity value +0.
8) Landolt rings are formed side by side with respect to each chart.

In each of the chart sections 50j to 50m, a Landolt ring having a visual acuity value of three levels is formed for one chart section. Further, since five Landolt rings are formed for each one of the visual acuity values, a total of 15 Landolt rings are formed for one chart portion.

More specifically, the chart unit 50j has decimal visual acuity values of 0.2, 0.25, and 0.32 (log visual acuity value +0.
7, +0.6, +0.5) is the chart section 50
In k, there are three types of decimal visual acuity values of 0.4, 0.5, and 0.63 (logarithmic visual acuity values of +0.4, +0.3, and +0.2). 7, 0.8, 1.0
(Log visual acuity value +0.1, 0) is the chart part 5
At 0 m, fractional visual acuity values of 1.25, 1.6, 2.0 (-
0.1, -0.2, -0.3) are respectively formed on the chart. Here, a Landolt ring corresponding to a decimal visual acuity value of 0.7 is not the LogMAR target shown in the present embodiment, but is a standard visual acuity value in a driver's license or the like. ing.

The hiragana chart section 51 has a decimal visual acuity value of 0.1.
Five to one to 1.6 (logarithmic visual acuity value +1.0 to -0.2) are prepared separately. However, since the configuration of the target in each chart is the same as that of the Landolt ring, it will be described. Is omitted.

Next, the details of the mask plate 22 for applying an intended mask to the target on the chart section will be described with reference to FIG. The dashed line shown here is the center line in the longitudinal direction and the lateral direction in the chart portion.

Reference numeral 60 denotes an opening for displaying the entire chart surface without using a mask. 61 is the chart section 50
In the case where the optotypes of 3 rows × 5 columns are formed, such as j to 50 m, the upper, middle, and lower rows are presented separately in the horizontal direction (the direction in which the same visual acuity value is displayed). (Horizontal mask). Reference numeral 62 designates an opening for presenting three columns of a left end, a center, and a right end separately in a vertical direction (a direction in which different visual acuity values are displayed) in a chart portion in which optotypes of 3 rows × 5 columns are formed. (Vertical mask).

Reference numeral 63 denotes an opening (one-character mask) for individually presenting each optotype in the chart portions 50e and 50f in which the Landolt ring is formed in one row and two columns, and 64 denotes the chart portions 50g to 50i. For example, in a chart in which optotypes are formed in one row and three columns on one chart surface, the opening (one-character mask) for presenting each optotype individually. Also, 65 is 3 rows × 5 in one chart section such as the chart sections 50j to 50m.
An opening (one-character mask) for individually presenting each of the optotypes in which optotypes are formed in rows.

By the way, when fine evaluation is performed using the LogMAR visual target as described above, many types of visual acuity value visual targets (large visual targets) having a fractional visual acuity value of less than 0.2 are required. Further, in order to obtain an accurate visual acuity value, it is desirable to prepare as many optotypes having different visual acuity values as possible. Therefore, in the present embodiment, if only one chart unit can be formed depending on the size of the target, two different targets with the same visual acuity value are secured by using at least two chart units. When a plurality of optotypes having the same visual acuity value can be formed in one chart section, the maximum number of optotypes that can be formed in one chart section is maintained while maintaining the interval between adjacent optotypes so as not to hinder the inspection. (However, the upper limit was set to 5).

On the other hand, if as many different targets as possible are formed in one chart part while increasing the number of low visual acuity targets obtained by the LogMAR target, the configuration of the target formed on one chart part The types of patterns increase.
For this reason, if the configuration pattern is not devised, the mask plate 2
The number of openings to be formed on the second 2 becomes larger than before. In other words, when as many different targets as possible are formed in one chart part,
For example, 1 row x 1 column, 1 row x 2 columns, 2 rows x 3 columns, 3 rows x
A five-row configuration pattern is possible, but this would require only one
Many types of masks are required to apply character masks and horizontal masks, and it is difficult to make them with one mask plate disk.

Therefore, in the present embodiment, as described above, small-sized optotypes, such as the chart parts 50j to 50m, are composed of three rows and five columns on one chart part, and large-sized optotypes are used. All were constituted by one line on one chart part. As a result, even in the configuration of the chart section having a large number of low visual acuity targets, it is possible to present one horizontal row and one character for each visual acuity value to all the chart sections while minimizing the increase in mask types. (1) The mask can be efficiently used for one disk.

Next, details of the remote controller 40 are shown in FIG.
The configuration will be described.

Reference numeral 41 denotes a power switch, reference numeral 42 denotes an optotype changeover switch group for selecting an optotype (screen of a chart section),
Reference numeral 43 denotes a mask switch for selecting the type of mask to be applied to the optotype. Reference numeral 44 denotes an infrared light signal for position detection when adjusting the height position of the eye to be inspected, or the motor 2 by manual operation.
9 is a group of optical path changing switches for driving the target 9 and changing the optical path of the target. Reference numeral 46 denotes a display unit that displays a target presented to the apparatus main body 1 and a visual acuity value of the target. Reference numeral 47 denotes a change switch for changing a target to be presented by changing a mask position. Reference numeral 48 denotes a switch for switching the visual acuity value displayed on the display unit 46 between decimal display and log display.

Reference numeral 49 denotes an auto switch that also serves as a switch for inputting the correctness of the subject's response to the presented optotype and for executing a vision test program described later.
YES to use when answering correctly to the auto switch 49
There is a switch and a NO switch to be used in case of wrong answer or not knowing. In addition, the target is presented by the remote controller 4.
A transmission / reception unit 40a for transmitting / receiving a pulse signal using infrared light is provided at the front of 0.

The operation of the apparatus having the above configuration is described as follows.
This will be described with reference to the electric system block diagram of FIG.

After the subject is located at a predetermined position in front of the apparatus main body 1 (in this embodiment, the distance from the window 2 is 0.9 m), the examiner operates the remote controller 40 to perform a visual acuity test. . The desired target is presented by operating the target switch group 42, the mask switch 43, and the change switch 47. The optotype and mask information signals emitted from the remote control transmission / reception unit 40a are received by the light receiving unit 31 provided inside the apparatus main body 1 through the transmission / reception window 4. The signal received by the light receiving unit 31 is processed by the arithmetic and control unit 3 through a signal processing circuit 33.
Sent to 0. The arithmetic and control unit 30 controls the motor 2 to set the chart unit and the mask opening corresponding to the signal received based on the signal from the signal processing circuit 33 in the optical path.
1 and 23 are driven. Further, the arithmetic and control unit 30 transmits the target information corresponding to the presented target from the light emitting unit 32 through the signal processing circuit 34. The transmitted signal related to the target information is received by the transmission / reception unit 40a on the remote controller side. The received optotype information is displayed on the display section 46 together with the visual acuity value, thereby preventing a discrepancy between the display contents and the presented optotype.

Next, a description will be given of an automatic examination in which the next visual acuity target is automatically presented simply by inputting the correctness of the response of the subject using the auto switch 49.

The examiner operates the optotype changeover switch group 42, the masking switch 43, and the change switch 47 to present one optotype suitable for the subject. The subject is asked to answer the interpretation result of the presented target. The examiner confirms the correctness of the response from the subject to the presented target, and responds to the result with the YES switch of the auto switch 49 or N
Press the O switch. As a result, an automatic inspection program described below is executed. Also, the auto switch 49
All the correct / incorrect information input at is recorded in the memory 35,
It is used for the subsequent determination routine and calculation of the final visual acuity value of the subject.

The determination routine of the automatic inspection program according to the present embodiment will be described below with reference to FIGS. 11, 12, and 13, and an example of a method of obtaining a visual acuity value using this determination routine will be described with reference to FIG. I do. Note that this automatic inspection program is stored in a storage circuit of the arithmetic and control unit 30.

In FIG. 9, the numeral (-
0.2 to +0.3) represents the logarithmic visual acuity value of the presented target. In addition, “○” indicates a correct answer, “X” indicates a case where an incorrect answer or a break of the optotype was not found, and a number surrounded by a circle indicates an examination order.

First, the judgment is made in accordance with a correct answer (when the YES switch is pressed) with respect to the presented target (in the example of FIG. 9, the first presented target was set to the logarithmic visual acuity value +0.3). , The next presentation target is determined. First, the arithmetic and control unit 30 confirms whether or not a Log determination is being performed (STEP 1). Log
In the judgment, it is assumed that the subject failed to obtain the maximum value of the visual acuity stage (visual acuity value) in which the majority of correct answers were obtained at the same visual acuity value and the majority of correct answers were not obtained by the optotype determination solution a plurality of times. This means that the minimum value of the visual acuity level has already been determined, and the remaining visual acuity target is merely determined in these two visual acuity levels.

Here, since this is the first target identification,
It does not mean that the Log is being judged. Next, it is determined whether or not the target is a target that has been lowered by two stages (+0.2 minutes in logarithmic visual acuity value) from the target of the presently presented visual acuity stage (STEP 2). If the target is not a target, it is further determined whether there has been any wrong answer in the previous tests (STEP
3).

If no wrong answer has been made, it is determined whether the currently displayed visual acuity level is a visual acuity value one step lower than the maximum visual acuity value (+1.3 as a logarithmic visual acuity value). It is determined whether or not it is the maximum visual acuity value (+1.4 in logarithmic visual acuity value) (STEP 4 and STEP 5).

If NO in STEPs 4 and 5,
The arithmetic and control unit 30 rotates the optotype disc plate and the mask plate 22 to present the optotype (a visual acuity value +0.1 optotype) on which the one-letter mask with a two-step higher visual acuity is applied to the subject. (Step 6). If this vision stage is also answered correctly,
After STEP, the visual acuity stage is further increased by two stages.

Next, the visual acuity value increased by two steps -0.0.
If a wrong answer is given for the target 1, the examiner will use the auto switch 4
Press the NO switch of No. 9. When the NO switch is pressed,
The determination is made according to the flowchart shown in FIG. 12 (the determination routine when NO is pressed), and the next presentation target is determined. After passing through STEP 1 'as in FIG. 11, it is determined whether the visual acuity level has increased by two steps (STEP 2'). In this case, since it has been raised by two steps, the arithmetic and control unit 30 lowers the visual acuity level of the optotype by one step and presents the optotype having a logarithmic visual acuity value of 0 to the subject (STEP 7 ').

Next, when a correct answer is obtained with the optotype having the logarithmic visual acuity value of 0, the judgment is made according to the judgment routine of FIG. After going through STEPs 1 and 2, the process proceeds to STEP 3. Since there was an incorrect answer at the logarithmic visual acuity value of -0.1, it is determined whether there are three correct answers at that visual acuity level (STEP 8). Here, since the correct answer has not been made three times, the calculation / control unit 30 presents another target at the same visual acuity level.

In this manner, the target is discriminated at logarithmic visual acuity value 0, and if a correct answer is made three times in the visual acuity stage, after STEP 8, the visual target becomes the maximum visual acuity value (log visual acuity value-0). .3) is determined (STEP 9), and if it is not the maximum visual acuity value, the visual acuity level is increased by one (step 10 from logarithmic visual acuity value 0 to log visual acuity value -0.1).

Next, it is determined whether the wrong answer has been made three times in the visual acuity stage which has been raised by one stage (STEP 11). If not, an optotype different from the previously presented optotype is presented to the subject. When the presented target is answered correctly, different targets having the same visual acuity level are presented according to the determination routine of FIG. Next, when the presented target is incorrectly answered, different targets having the same visual acuity level are presented according to the determination routine of FIG.

In this way, the target is discriminated several times based on the logarithmic visual acuity value of -0.1.
After 1 'to 3', STEP 8 ', and STEP 9', the visual acuity stage is lowered by one stage (STEP 10 '), and it is determined whether there are three correct answers (STEP 11'). Performs the Log judgment routine from.

FIG. 13 shows a flowchart of the Log determination routine. Of the five optotypes already having a log visual acuity value of 0, a majority of three correct answers are obtained,
Of the five optotypes at the logarithmic visual acuity value of -0.1, three incorrect answers, which are the majority, have been obtained, so that all subsequent optotype determinations are handled during Log determination.

In this Log determination routine, unshown optotypes are sequentially presented from the visual acuity stage in which there are three correct answers, and after all optotypes (here, 5) are presented, an incorrect answer Are presented and discriminated by presenting all the unpresented optotypes of the visual acuity stage (the visual acuity stage raised by one stage) having three times.

In this manner, in two visual acuity stages, that is, a visual acuity stage in which three correct answers are obtained and a visual acuity stage in which a wrong answer is obtained three times, it is possible to determine all the optotypes (correct / incorrect). The calculation / control unit 30 calculates the visual acuity value of the subject from the correct / wrong information recorded in the memory 35.

The calculation method of the visual acuity value in this embodiment is as follows.
Perform as follows. When there are five optotypes in the same visual acuity value,
One target has a log visual acuity value of 0.02 minutes. If all the targets at the same visual acuity value (visual acuity level) are correct, the visual acuity value at that visual acuity level is obtained. If there is a wrong answer, a logarithmic visual acuity value of 0.02 minutes is added to the visual acuity value at that visual acuity level by the number of wrong answers. By applying this to the maximum visual acuity level that could be determined and the minimum visual acuity level that could not be determined, a finer visual acuity value is obtained in these two visual acuity levels. The final visual acuity value is obtained by averaging the two obtained visual acuity values, and this is used as the visual acuity value of the subject.

In the example shown in FIG. 9, the logarithmic visual acuity value of 0, which is the maximum visual acuity level, is 4 correct answers and 1 incorrect answer, so that the fine visual acuity value at this visual acuity level is 0 + 0.02. ×
1 = 0.02. On the other hand, when the logarithmic visual acuity value of −0.1, which is the minimum visual acuity level that could not be determined, was twice correct,
In this case, the fine visual acuity value at this visual acuity stage is -0.0.
1 + 0.02 × 3 = −0.04. By taking the average of these two visual acuity values, the final visual acuity value of the subject is -0.01.

The result is displayed on the display unit 46 as a logarithmic visual acuity value−0.0.
It is displayed as 01. If the user wants to know the corresponding decimal visual acuity, the operation / control unit 30 converts the logarithmic visual acuity value to the corresponding decimal visual acuity value by using the changeover switch 48 and displays it on the display unit 46 (decimal visual acuity value 1. 023).

As described above, using the correct / incorrect information (correct answer rate) of all the targets in the maximum visual acuity stage that can be determined and the correct / incorrect information of all the targets in the minimum visual acuity stage that cannot be determined, Since the visual acuity value of the subject is obtained, a fine and accurate visual acuity value can be obtained as compared with the conventional visual acuity value determination.

In the present embodiment, it is determined whether or not the visual acuity level has been determined based on the correctness of three of the five visual targets. However, the present invention is not limited to this. Majority (or more than 60%) of prepared targets
If it has been obtained, it may be determined whether or not it can be determined. Further, when there are only two optotypes, it is sufficient that the visual acuity level can be determined only when all (2) optotypes are correctly answered.

When automatically presenting the next target in response to the subject's response, the maximum visual acuity level finally determined and the minimum visual acuity level that cannot be determined can be determined. The inspection procedure is not limited to this as long as it is an inspection procedure that can obtain the correct / incorrect information of all the targets in the two visual acuity stages.

For example, as shown in FIG. 10, when a certain target (log visual acuity value -0.1) is incorrectly answered, the visual acuity stage is set to 1
It is also possible to lower the stage, determine all the targets at the visual acuity level (log visual acuity value 0), and then determine all the targets at the visual acuity stage (log visual acuity value -0.1) to which the previous answer was wrong. In this case, if there is an incorrect answer three times earlier with a logarithmic visual acuity value of 0, the visual acuity level may be further reduced by one step and the same may be performed.

In the above embodiment, the visual acuity test apparatus capable of presenting the optotype in a small space has been described as an example. However, the present invention is not limited to this, and the visual acuity test apparatus capable of individually presenting the optotypes by electric control. Should be fine.

In addition, the response result of the subject may be input with a joystick. In this case, if the automatic test program is performed up to the judgment of correctness of the presented target, the test can be performed more easily.

[0069]

As described above, according to the present invention,
The accuracy of the eye test is improved, and detailed evaluation can be easily performed.

[Brief description of the drawings]

FIG. 1 is a view showing an apparatus main body.

FIG. 2 is a diagram showing an optical system arranged inside the apparatus main body.

FIG. 3 is a diagram showing an optical system arranged inside the apparatus main body.

FIG. 4 is a diagram showing details of a target disc plate 20;

FIG. 5 is a diagram showing details of a mask plate 22;

FIG. 6 is a diagram showing details of a Landolt ring chart unit 50;

FIG. 7 is a diagram showing details of a remote controller 40;

FIG. 8 is an electric block diagram.

FIG. 9 is a diagram illustrating an example of a technique for obtaining a visual acuity value;

FIG. 10 is a diagram showing an example of a technique for obtaining a visual acuity value.

FIG. 11 is a flowchart illustrating a determination routine when a YES switch is pressed.

FIG. 12 is a flowchart illustrating a determination routine when a NO switch is pressed.

FIG. 13 is a flowchart illustrating a Log determination routine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Device main body 2 Window 4 Transmission window 20 Target disk board 21 Motor 22 Mask board 23 Motor 30 Calculation / control part 40 Remote control 49 Auto switch

Claims (6)

[Claims] 1. A visual acuity test apparatus for presenting a visual target and inspecting a subject's visual acuity, wherein a plurality of contrast visual targets represented by geometric series and having the same visual acuity value level are prepared. An optotype presenting means for selectively presenting one of the optotypes, an input means for inputting a result of the subject's response to the presented optotype, and an optotype to be presented next based on the correctness of the response to the presented optotype Storage means for storing a program for sequentially determining the visual target, an optotype presenting control means for controlling the optotype presenting means in accordance with the program, and an arithmetic means for obtaining a visual acuity value of the subject from a correct answer rate of a response in a certain visual acuity value stage. A visual acuity testing device comprising: 2. The visual acuity testing apparatus according to claim 1, wherein the program includes all the visual targets belonging to the first visual acuity value stage for which a majority of correct answers are obtained, and the second visual acuity value that is one higher than the first visual acuity value stage. A visual acuity testing apparatus, comprising: a program including a step of presenting all visual targets belonging to a stage, wherein the calculating means calculates a visual acuity value from a correct answer rate in the first and second visual acuity value stages. 3. The visual acuity testing apparatus according to claim 2, wherein the program presents all the optotypes belonging to the first visual acuity value stage and then presents all the optotypes belonging to the second visual acuity value stage. An eyesight test apparatus characterized by including: 4. The visual acuity test apparatus according to claim 2, wherein the program presents an optotype at the previous second visual acuity value stage when a majority of correct answers is obtained at the first visual acuity value stage, and provides a second visual acuity value. A visual acuity test apparatus comprising the step of presenting the remaining visual targets belonging to the first visual acuity value stage again when the majority of correct answers cannot be obtained in the visual target presentation at the value stage. 5. The visual acuity test apparatus according to claim 1, further comprising: display means for displaying the visual acuity value obtained by said arithmetic means; and a visual acuity value to be displayed on said display means. Switching means for mutually switching to a format,
A visual acuity testing device comprising: 6. The visual acuity test apparatus according to claim 1, wherein the input means is means for the examiner to obtain a response result of the subject and input the correctness thereof.