JPH049411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an optometry device that measures the refractive power of an eye to be examined. This invention relates to improvements in a subjective optometry device that measures force.

(Prior Art) Conventionally, a test subject is made to visually recognize a test optotype through a corrective lens for changing the refractive power of the subject's eye, and the test optotype is determined based on the patient's response. The refractive power of the corrective lens is changed until the test target can be properly seen, and the refractive power of the eye to be examined is measured based on the refractive power of the corrective lens when the test target can be properly seen. A self-aware optometry device is known.

By the way, some of this type of subjective optometry devices are equipped with a cross cylinder lens in order to accurately measure the astigmatic axis and the astigmatic power. This cross cylinder lens is composed of an astigmatic lens in which the absolute value of the refractive power of the strong principal meridian and the weak principal meridian, which are perpendicular to each other, is equal in absolute value and has different positive and negative values, and the position is 45 degrees midway between the positive and negative axes. When the handle attached to the lens is picked up and rotated to turn the lens inside out, the plus and minus axes swap places, allowing precise measurement of the astigmatic axis and astigmatic power.

In other words, when accurately measuring the astigmatic power, align the strong principal axis of the cross cylinder lens with the subject's astigmatic axis direction, hold the handle of the cross cylinder, and turn the cross cylinder inside out. Precise measurement is performed by comparing the visibility of the test optotype in the first state and the second state after inversion. In addition, in the case of precise measurement of the astigmatism axis, the strong principal meridian should be 45
The cross cylinder lens is rotated so as to form an angle, and in that state, the cross cylinder lens is turned inside out, and the astigmatic axis is precisely measured based on the visibility of the test optotype before and after the inversion.

(Problem to be Solved by the Invention) However, in this conventional subjective optometry device using a cross-cylinder lens, the examinee is asked to spend time in either state before and after the cross-cylinder lens is inverted. If it is longer than , the longer you look at it, the better you will see, and there is a problem that accurate measurements cannot be made unless you look at the test target for the same amount of time. In addition, it is impossible to obtain accurate measurement results in a single measurement, and measurements must be performed repeatedly, which causes troublesome measurement operations.

Therefore, instead of having the examiner change the state by reversing the cross cylinder lens himself, we designed the system to automatically repeat the state reversal at a fixed period.
A method has been proposed in which the cross cylinder lens is automatically reversed between two states to confirm which state provides better visibility. The operator must assemble the operating procedures himself, and there are many operating switches, which must be used appropriately depending on the measurement, which poses problems such as the risk of erroneous operation and the need for skill in measurement. be.

(Object of the Invention) The present invention has been made in consideration of the above circumstances, and its purpose is to facilitate measurement operations when the cross cylinder lens is configured to alternately and automatically reverse. It is an object of the present invention to provide a self-conscious optometry device that can quickly perform accurate measurements while avoiding measurement operation errors as much as possible.

(Means for Solving the Problems) The features of the subjective optometry device according to the present invention include a reversal drive switch that alternately drives the cross cylinder optical system in reverse between a first state and a second state; The apparatus includes a feed switch that changes at least one of the astigmatic axis and the astigmatic power by a predetermined step when operated after setting either the state or the second state.

(Function) According to the present invention, the examiner does not have to operate each switch and assemble the measurement procedure each time, which reduces the burden on the examiner and allows him to perform measurements without having to worry about operations. You will be able to concentrate on it.

(Example) Hereinafter, an example of the subjective optometry device according to the present invention will be described with reference to the drawings.

In FIG. 1, 1 is an eye to be examined, and in front of this eye 1 is provided a disk 3 that rotates around an axis 2, and a plurality of spherical lenses are arranged on the disk 3. indicates the plurality of spherical lenses. Each of these spherical lenses has a different spherical power. The disc 3 is rotationally driven by a pulse motor 6, and the pulse motor 6 is controlled based on a control signal from a control calculation circuit described later. A spherical lens having a predetermined spherical power is set on the visual axis 7 of the eye 1 by this pulse motor 6, and here,
A spherical lens indicated by reference numeral 4 is set. A cylindrical power conversion lens system 8 is provided in front of the spherical lens 4.

This cylindrical power conversion lens system 8 is composed of a first cylindrical lens 9 having a positive cylindrical power and a second cylindrical lens 10 having a negative cylindrical power.
Each cylindrical lens 9, 10 is driven by a pulse motor 11, 12
Each pulse motor 11, 12 is controlled by a control calculation circuit 13, which will be described later. This cylindrical power conversion lens system 8 has a function of correcting the astigmatic power and the astigmatic axis, and here functions as a so-called cross cylinder optical system. The subject visually recognizes a test optotype (not shown) through the cylindrical power conversion lens system 8 and the spherical lens, and undergoes measurement of the subject's eye 1. The control calculation circuit 13 has a predetermined program incorporated therein, and is configured to drive and control the pulse motors 6, 11, and 12, as well as having functions described later.

This control calculation circuit 13 is connected with a program circuit 14 for precise measurement of astigmatic power, a program circuit 15 for measuring astigmatic axis, and an operation switch 16, and is connected intermittently to a measurement result display section 17 that displays astigmatic power and astigmatic axis angle. An identification sound generation circuit 18 that generates an identification sound is connected thereto. Operation switch 16
a reversal drive switch 19 for reversing the cross cylinder optical system between a first state and a second state;
Proceed with the program to select astigmatic axis precision measurement mode.
The RUN switch 20 sequentially switches the control calculation circuit 13 to the astigmatic power precision measurement mode, and when operated after setting either the first state or the second state, the state is reversed and at least one of the astigmatic axis and the astigmatic power is set. It is composed of a YES switch 21 which serves as a feed switch that changes by a predetermined step. Switch 19 is provided on the examiner's side, and switches 20 and 21 are provided on the examinee's side. The pulse motors 11 and 12 are controlled according to programs included in a program circuit 14 for precise measurement of astigmatic power and a program circuit 15 for measuring astigmatism axis, respectively. This program will be explained along with its operation, and then the cylindrical lenses 9 and 10 will be explained with reference to FIGS. 2 and 3.

The cylindrical lens 9 has a positive cylindrical power +C ₀ as shown in FIG. 2, and the cylindrical lens 10 has a negative cylindrical power -C ₀ as shown in FIG.
In order to generate a cylinder power C and a cylinder axis A with these two cylinder lenses 9 and 10, each cylinder lens 9 and 10 is set to θ ₁ and θ ₂ calculated based on the following formula. .

θ ₁ = 1/2 [sin ^-1 (C12C ₀ )] + A ... (1) θ ₂ = -1/2 [sin ^-1 (C/2C ₀ )] + A ... (2) It is clear from this equation that As such, the first cylindrical lens 9
By rotating the cylindrical lens 9 and the second cylindrical lens 10 at equal angles in opposite directions, the cylindrical power C can be converted, and the first cylindrical lens 9 and the second cylindrical lens 10 are rotated at equal angles in the same direction. This allows the cylinder axis A to be converted, and by independently rotating the first cylinder lens 9 and the second cylinder lens 10, a desired cylinder power C and cylinder axis A can be set.

Next, the measurement procedure will be described, including the functions of the control calculation circuit 13 and the programs of the astigmatic power precision measurement program circuit 14 and the astigmatic axis precision measurement program circuit 15.

First, the test subject is made to visually recognize the test target through the spherical lens 4 and the cylindrical power conversion lens system 8, and the pulse motor 6 is driven in response to the test subject's response to rotate the disc 3. Correct the spherical power of 1.
Next, a visual acuity chart for astigmatism testing is visually confirmed, and the first cylindrical lens 9 and the second cylindrical lens 10 are rotated by the pulse motors 11 and 12 according to the test subject's response, and the astigmatism power of the test subject is determined. Perform initial settings by correcting the astigmatism axis. After this initial setting is completed, the astigmatic axis and astigmatic power are precisely measured.

First, precise measurement of the astigmatic axis will be explained.

First, operate the RUN switch 20. Then,
The control calculation circuit 13 enters the astigmatic axis precision measurement mode. That is, when the RUN switch 20 is turned on, the cylindricity converting lens system 8 functions as a cross cylinder optical system. The control calculation circuit 13 starts calculation based on the program of the astigmatic axis precision measurement program circuit 14. This calculation uses the cylindrical power A and the cylindrical axis C obtained by correcting the astigmatic axis and the astigmatic power. Control calculation circuit 1
3 is a cylindrical lens 9 using the above equations (1) and (2).
The cylindrical axis θ ₁₁ of the cylindrical lens 10 and the cylindrical axis θ ₁₂ of the cylindrical lens 10 are calculated, and based on the calculation results, the cylindrical lenses 9 and 1 are
Set the cylinder axes of 0 to θ ₁₁ and θ ₁₂ .

θ ₁₁ = 1/2 [sin ^-1 (C ² +ΔC ² )] +1/2tan ^-1 (ΔC/C) ...(3) θ ₂₁ = 1/2 [sin ^-1 (C ² +ΔC ² )] +1 /2tan ^-1 (ΔC/C) ...(4) In this equation, ΔC=0.25 to 1.
This is the first state (step S1 in Figure 4).
reference). When set to this first state, the identification sound generation circuit 18 generates one intermittent sound. Next, when the examiner operates the reversing drive switch 19, the cylindrical lenses 9 and 10 move to the cylindrical axis θ ₁₂ , which is determined by the following equation.
θ is set to ₂₂ .

θ ₁₂ = 1/2 [sin ^-1 (C ² + ΔC ² )] -1/2tan ^-1 (ΔC/C) ...(5) θ ₂₂ = -1/2 [sin ^-1 (C ² + ΔC ² ) ] -1/2tan ^-1 (ΔC/C) ...(6) This state becomes the second state (step S3),
When in the second state, two intermittent sounds are generated. Thereafter, each time the examiner operates the reversing drive switch 19, the first state and the second state are alternately set (steps S7, S1). The test subject compares the visibility of the test index in the first and second states, which are set repeatedly, and when it is reversed to a state where it can be clearly seen.
You will be instructed to press the YES switch 21 (steps S7 and S10). The control calculation circuit 13 has a function of determining in which state the YES switch 21 is pressed. For example, in the second condition the subject
Pressing the YES switch 21 means that the initially set cylinder axis A is not appropriate. At this time, the cylinder axis A is slightly rotated by -1/2 tan ^-1 (0.125/C) based on equations (1) and (2) so that it approaches the + direction (steps S5 and S6). Also, YES in the first state
When switch 21 is pressed, the cylinder axis A is halved.
Make a slight rotation ⁽ step
S111, S12). Then, the first state and the second state are alternately and repeatedly set based on the newly set cylinder axis A (steps S1 to S11). Therefore,
If the subject's visibility is the same in the first state and the second state, the RUN switch 20 is pressed (step S12). Then, the astigmatic axis precision measurement mode ends, and the subjective optometry device temporarily stores the measured value of the astigmatism axis obtained through this precision measurement, and changes from the astigmatism axis precision measurement mode to the astigmatism power precision measurement mode.

After obtaining the precise measurement result of this astigmatic axis, the astigmatic power is precisely measured. This precision measurement of the astigmatic power uses the precision measurement results of the astigmatism axis. That is, the astigmatic power is slightly changed while keeping the precise measurement value of the astigmatic axis as it is, and the control calculation circuit 13 is a program circuit 1 for precision measurement of the astigmatic power.
Calculation is started based on the program in step 5.

The control calculation circuit 13 sets the cylindrical axes of the cylindrical lens 9 to θ ₁₁ and θ ₁₂ using equations (1) and (2) described above.

θ ₁₁ = 1/2 [sin ^-1 (C ² + ΔC ² )] -1/2tan ^-1 (ΔC/C) ...(7) θ ₂₁ = -1/2 [sin ^-1 (C ² + ΔC ² ) ] −1/2tan ⁻¹ (ΔC/C) ...(8) In this equation, ΔC=0.25 to 1.

This state is defined as the first state (steps in Figure 5).
(See S13). When set to this first state, the identification sound generation circuit 18 generates one intermittent sound. This one
The intermittent sounds correspond to identification sounds indicating the first state.
Next, when the reversal drive switch 19 is pressed, the cylindrical lenses 9 and 10 are set to the cylindrical axes θ ₁₂ and θ ₂₂ determined by the following equations.

θ ₁₂ = 1/2 [sin ^-1 (C ² + ΔC ² )] -1/2tan ^-1 (ΔC/C) ...(9) θ ₂₂ = -1/2 [sin ^-1 (C ² + ΔC ² ) ] -1/2tan ^-1 (ΔC/C) ...(10) This state becomes the second state (see step 15 in Figure 5), and in this second state two intermittent sounds are generated. be. Thereafter, each time the examiner presses the reversal drive switch 19, the first state and the second state are alternately set (steps S14, S15). The subject compares the visibility of the test optotype in the first and second states that are repeatedly set, and is instructed to press the YES switch 21 (steps S17 and S22) when the test target is reversed to a clearly visible state. be done. If the subject presses the YES switch 21 in the second state, it means that the initially set cylinder power C is not appropriate, so the cylinder power C is automatically set based on formulas (1) and (2).
Make a slight change by 0.25 days (step S18).
Further, when the YES switch 21 is pressed in the second state, a slight change of -0.25 diopter is made (step 23), contrary to the above. Then, the first state and the second state are alternately and repeatedly set by the reversing drive switch 19 based on the newly set cylindrical power (steps S13 to S23). Therefore, the subject
If the state and the second state are equally visible,
Press RUN switch 20 (step S24). Then, steps S13 to S23 are repeated until the RUN switch 20 is pressed. If the test target can be clearly seen, the test subject can press the RUN switch 2.
Press 0 (step S24). Then, the astigmatic power precise measurement mode ends, and the subjective optometry device outputs and displays the measured value of the astigmatic power and the measured value of the astigmatic axis obtained by this precise measurement. This ends the measurement.

In this example, the spherical power conversion lens is
We arranged spherical lenses with various spherical powers on a disc 3 and rotated the disc 3 to convert the spherical powers. It is also possible to adopt a configuration in which the lens is moved in its axial direction and the spherical power is converted at random.

In this embodiment, the cylindrical power conversion lens system 8 is configured to double as a cross cylinder lens system, but separately from the cylindrical power conversion lens system 8, a first cylindrical lens having a positive cylindrical power and a negative cylindrical lens system are used. It is also possible to provide a cross cylinder optical system in which second cylindrical lenses having dioptric powers are arranged orthogonally to each other, and to drive this cross cylinder optical system.

Further, in this embodiment, a case has been described in which the present invention is applied only to a subjective optometry device, but the present invention can also be applied to a so-called autorefractometer that can be used for both subjective and objective purposes.

(Effects of the Invention) As explained above, according to the present invention, the subjective optometry device includes a reversal drive switch that alternately drives the cross cylinder optical system in reverse between the first state and the second state, A feed switch that changes at least one of the astigmatic axis and the astigmatic power by a predetermined step when operated after setting either the first state or the second state; A control that determines whether the feed switch has been operated and automatically sets the direction of change in predetermined steps so that the direction of feed in the first state and the direction of feed in the second state are opposite to each other. Because it has a circuit, measurements can be performed automatically according to a preset program, and the examiner does not have to operate each switch and assemble the measurement procedure each time. The burden is lightened, the user can concentrate on measurement without having to worry about operations, and the effect is that accurate measurements can be performed quickly.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main part configuration of the subjective optometry device according to the present invention, FIG. 2 is a plan view of the first cylindrical lens shown in FIG. 1, and FIG. 3 is a plan view of the second cylindrical lens shown in FIG. 1. FIG. 4 is a plan view of the lens, FIG. 4 is a flowchart for explaining the case of performing precise measurement of the astigmatism axis using the subjective optometry device according to the present invention, and FIG. 5 is a diagram showing the subjective optometry device according to the present invention. This is a flowchart for explaining the case where the astigmatic power is precisely measured using the method. DESCRIPTION OF SYMBOLS 1... Eye to be examined, 4... Spherical lens, 8... Cylindrical power conversion lens, 9... First cylindrical lens, 10...
...Second cylindrical lens, 13...Control calculation circuit, 14
...Program circuit for precision measurement of astigmatic axis, 15...
Program circuit for precision measurement of astigmatic power, 16... Operation switch, 19... Reversing drive switch, 20...
...RUN switch, 21...YES switch.

Claims (1)

[Claims] 1. In a subjective optometric apparatus having a cross-cylinder optical system, a reversal drive switch for driving the cross-cylinder optical system alternately between a first state and a second state by an examiner's operation; a feed switch that changes at least one of the astigmatic axis and the astigmatic power by a predetermined step when operated after setting either the second state or the second state;
and a determination means for determining whether or not the feed switch is operated in either state or the second state; A self-aware optometry device comprising: a control circuit that automatically sets the direction of change in each of the predetermined steps so that the direction in which the eye is sent is opposite to the direction in which the eye is sent.