JPH0262249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an astigmatism testing device that more effectively measures astigmatism power and astigmatism axis in a subjective eye refraction measuring device.

[Conventional technology]

As an astigmatism test method, the examinee is shown an astigmatism chart such as a radiation or Raubichiek optotype, and the astigmatism axis and There is a method of changing the dioptric power, but this is done by first setting the dioptric power of the astigmatic lens to 0, then confirming which direction the line that appears particularly dark is, and determining the astigmatic axis of the astigmatic lens to be added from that direction. Next, the astigmatic power is added sequentially so that the shading of the line is uniform.

Another method for astigmatism testing is a method using a cross cylinder lens.

[Problem that the invention seeks to solve]

Among the above conventional techniques, the former method involves correcting the astigmatism axis to the opposite side to the side where the line that appears darker changes when the position changes, but this method requires skill in the examination, is time consuming, and is costly. There was a problem with the lack of accuracy due to the fatigue of the examiner. Further, in the latter case, the astigmatic axis and the astigmatic power need to be operated several times each, and there are problems in that the operations are complicated and the mechanism is also complicated.

The present invention is intended to solve the above-mentioned problems, and includes residual astigmatism that occurs when the astigmatic characteristics of the eye to be examined are not corrected by an optical characteristic changing means placed in front of the eye to be examined; That is, by measuring the axis of the composite astigmatism generated by combining the astigmatism of the eye to be examined and the optical property changing means at least twice with different characteristics of the optical property changing means,
It is an object of the present invention to provide an astigmatism testing device that can immediately measure the astigmatic power and astigmatism axis of an eye to be examined.

[Means to solve the problem]

In order to achieve the above object, the astigmatism testing device of the present invention switches and arranges a cylindrical lens on the visual axis of the eye to be examined, or rotates the cylindrical lens placed on the visual axis around the optical axis. an optical property changing means capable of changing at least one of the cylindrical power and the cylindrical axis added to the eye to be examined; a means for detecting a cylindrical component added to the eye by the optical property changing means;
an astigmatism axis testing optotype that is visually recognized by the eye to be examined through a cylindrical lens on the visual axis; a calculation means for calculating the degree of astigmatism and the astigmatism axis of the eye to be examined; and an arbitrary first cylindrical component of the optical property changing means. A first synthetic astigmatism axis that occurs when the astigmatism of the eye to be examined is not corrected and a second synthetic astigmatism axis that occurs when a second cylindrical component different from the first cylindrical component is added to the eye to be examined are calculated by the calculation means. and an input means for inputting data, and is characterized in that the astigmatism power and astigmatism axis of the eye to be examined are calculated from the first and second cylindrical components and the first and second composite astigmatism axes.

The input means may consist of an index placed on the outer periphery of the optotype for astigmatism axis testing, a moving means for moving the index on the outer periphery, and an input switch for inputting the position of the index moved by the moving means. good.

Moreover, the optical property changing means is a first
The cylindrical component can be determined based on preliminary measurements by an objective refractometer or a lens meter.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of the subjective eye refraction measuring device for measuring the astigmatic axis and astigmatic power according to the present invention, in which 1 is the eye to be examined, 2 is the visual axis, and a spherical lens 3 is placed on the axis. and 4, and cylindrical lens 5
and 6 are arranged. 7 and 8 are rotatable spherical lens plates on whose circumferences spherical lenses 3 and 4 are respectively attached; 9 and 10 are rotatable spherical lens plates on whose circumferences cylindrical lenses 5 and 6 are respectively attached; A possible cylindrical lens plate, 11, is the rotation axis of the spherical lens plates 7 and 8 and the cylindrical lens plates 9 and 10. Reference numerals 12 and 13 are spherical lens switching motors for rotating the spherical lens plates 7 and 8, respectively, and the rotation of the spherical lens plates 7 and 8 switches the other spherical lenses 3 and 4 having different refractive powers. Reference numerals 14 and 15 are cylindrical lens switching motors for rotating the cylindrical lens plates 9 and 10, respectively, for switching between the other cylindrical lenses 5 and 6 having different refractive powers. 16 and 17 are
The cylindrical lenses 5 and 6 are fixed rotatably around the visual axis 2, respectively, and 18 is a gear that meshes with the gears 16 and 17 and is connected to the shaft rotation motor 20 via the gear 19. . FIG. 2 shows an embodiment of the optotype projecting device, in which 21 is a radiographic target and 22 is an index fixed to a gear 23. In FIG. 26 is a motor for rotating the index 22 via gears 25 and 23, and the Laubichek optotype 28 via the gear 25 around the optotype projection optical axis 24; 27 is a motor for rotating the optotype 21 around another optotype, e.g. A motor for switching to the Laubichek optotype 28 shown in FIG. 3b, 29 is an illumination lamp, 30
3 is a condenser lens, a motor for switching between the target 21 or 28, 29 is an illumination lamp, and 3 is a condenser lens.
0 is a condenser lens, optotype 21 or 28
is projected onto the visual axis of the eye 1 to be examined.
FIG. 3a shows a front view of optotype 21 and index 22. FIG.

FIG. 4 is a control block diagram showing one embodiment of the present invention. 31 is an external interface for transmitting each preliminary data of spherical power, astigmatic power, and astigmatic axis from an external device such as an objective refraction measurement device (not shown) to the input circuit 32; 33 forms an arithmetic control circuit. CPU, 34 is a program storage circuit ROM, 35 is a storage circuit for input data, etc.
RAM, 37 to 41 are controlled by the spherical lens switching motor 12, respectively, according to the signal from the output circuit 36.
13. A motor drive circuit for driving the cylindrical lens switching motors 14, 15 and the cylindrical shaft rotation motor 20, which sets the lens according to each data on the visual axis 2 and also sets the cylindrical shaft. . 42 and 43 are motor drive circuits for driving the target rotation motor 26 and the target switching motor 27, respectively.

44 to 46 are rotary encoders operated by the examiner. 44 is a rotary encoder for converting a spherical lens value, that is, an S value, 45 is a rotary encoder for converting a cylindrical lens value, that is, a C value, and 46 is a rotary encoder for converting a cylindrical axis value, that is, an A value. By rotating these, each value can be corrected. Can be done.
47 is a rotary encoder for rotating the optotype, which is particularly conveniently operated by the subject, and its signal is sent to the waveform shaping circuit 48 and the input circuit 3.
2. The target rotation motor 26 is rotated via the CPU 33, the output circuit 36, and the motor drive circuit 42, and the rotation signal is stored in the RAM 35. Reference numeral 49 is an optotype changeover switch, and 50 is an input switch for inputting a composite astigmatism axis, which will be described later, at least twice.

FIG. 5 is a diagram showing the principle of this invention. Assume that the astigmatic axis of the eye to be examined is θ, and the astigmatic power is C. The cylinder axis and cylinder power of the initially set astigmatic lens are θ ₁ and C ₁
Then, the astigmatic axis θ ₃ of the composite astigmatism that occurs between the two is tan2θ ₃ = Csin2θ−C ₁ sin2θ ₁ /Ccos2θ−C ₁ cos2θ ₁
... becomes. Next, set the cylinder axis and cylinder power as θ ₂
Similarly, the astigmatic axis θ ₄ of the composite astigmatism when C ₂ is tan2θ ₄ = Csin2θ−C ₂ sin2θ ₂ /Ccos2θ−C ₂ cos2θ ₂
... becomes. Here, if θ ₃ and θ ₄ are detected by the subject's consciousness, the astigmatic axis θ and the astigmatic power C of the subject's eye can be calculated from the known θ ₁ , c ₁ , θ ₂ , and c ₂ .

The operation of this invention will be explained below.

Preliminary measurements were made in advance using an external device (not shown) such as an objective refraction measuring device or an autolensmeter.
The S value, C value, and A value of the eye to be examined are input to the input circuit 32 through the external interface circuit 31, and the signals are sent to the spherical lens switching motors 12 and 13 via the CPU 33, output circuit 36, and motor drive circuits 37 to 41. The cylindrical lens switching motors 14 and 15 and the shaft rotation motor 20 are operated to set the spherical lens, cylindrical lens, and cylindrical shaft corresponding to the preliminary measurement values. That is,
This means that the initial settings described in the explanation of the principle have been made. The examiner operates the optotype switching motor 27 using the optotype switching switch 49 to select the radiation optotype 2.
1 and an index 22 or a Laubichek optotype 28 are presented to the eye 1 to be examined on its visual axis 2. When the preliminary measurement value does not match the subjective value of the subject's eye, only lines in a specific direction within the optotype appear dark. Therefore, the eye to be examined operates the optotype rotation encoder 47 and the index 22 is rotated by the optotype rotation motor 26, so that the eye to be examined 1 can move in the direction of the dark visible radiation of the radiation optotype 21 and the index 22 on the outer periphery. Detect the position where . When the examiner presses the input switch 50 in this state, the composite visual axis θ ₃ in the direction perpendicular to the direction of darkening is automatically input, and at the same time, the power of the cylindrical lens and/or the cylindrical axis have been previously set. Only the amount changes.

That is, the second setting described above can be performed.

Similarly, when the examiner detects the position where the direction of the dark visible radiation of the optotype 21 and the index 22 match with the eye to be examined and presses the input switch 50 again, the composite astigmatism axis θ ₄ is automatically input.

It is rotated by the optotype rotation motor 26, and
Detect the position where the line 8A appears dark.

The composite astigmatism axes θ ₃ , θ ₄ and 2 automatically input here
Substitute the set cylinder lens powers c ₁ , c ₂ and cylinder axes θ ₁ , θ ₂ into the above calculation formula and
3 and ROM 34 to determine the astigmatic power C and astigmatic axis θ of the eye to be examined. According to this value, each lens and cylinder axis are set on the visual axis 2 again by the motors 12 to 15 and 20, and the eye to be examined is
It can be confirmed that the density of the radiation of the radiographic target 21 in all directions is uniform.

In the above operation, for example, a voice synthesis circuit (not shown) is operated in conjunction with switching of the radiographic target 21,
It is also possible to make the examiner's operation easier by generating a voice such as ``Turn the optotype rotation encoder so that the index matches the darkest line, then press the switch.''

FIG. 6 shows another embodiment of the optotype device,
Lamps that turn on sequentially around the radiation of the astigmatism chart 59 are arranged, and the combined astigmatism axis is detected by lighting the lamp in the direction of the radiation that appears darker to the subject. A switch similar to the optotype rotation encoder 47 (not shown) is provided to change the lighting position of the lamp, and by inputting the lighting position using the input switch 50, the composite astigmatic axis can be automatically detected. can.

In all of the above embodiments, the lens exchange system and optotype system are electrically connected in order to automatically input the composite astigmatism axis, but such a dedicated optotype system is not prepared. Of course, even in this case, it is possible to calculate the astigmatic power and the astigmatic axis. For example, it is possible for the examiner to hear the direction of the composite astigmatism axis that the subject has confirmed by looking at the radiation chart, and input the composite astigmatism axis by operating the composite astigmatism axis input device.

In addition, in the embodiment, as a method of changing the power of the spherical lens added in front of the subject's eye, a method is described in which a plurality of spherical lenses are arranged on a spherical lens plate and the spherical lenses are switched by rotating the spherical lens plate. As mentioned above, it is also possible to change the spherical power by moving the spherical lens in the direction of the visual axis of the subject's eye.

Furthermore, as a method for changing the power of the astigmatic lens, in this embodiment, a method of arranging a plurality of astigmatic lenses on an astigmatic lens plate and rotating the astigmatic lens plate to switch the astigmatic lenses is shown.
A method is also possible in which the cylindrical power is continuously changed by relatively rotating two cylindrical lenses having the same absolute value of astigmatic power around the visual axis of the eye to be examined.

C. Effects of the Invention As is clear from the above invention, according to the present invention, the astigmatic power and astigmatism axis of the eye to be examined can be immediately tested by simply measuring and inputting the axis of composite astigmatism twice.

Furthermore, by performing a subjective astigmatism test according to the present invention based on preliminary data obtained from an objective eye refractive power measurement device, more accurate results can be obtained because the power of the composite astigmatism becomes smaller. .

[Brief explanation of drawings]

Figure 1 is a side sectional view of the subjective eye refraction measuring device, Figure 2 is a side sectional view of the optotype projection device, and Figure 3 a.
4 is a control block diagram, FIG. 5 is a diagram of the principle of the present invention, and FIG. 6 is another embodiment of the optotype device. 2... Visual axis, 5, 6... Cylindrical lens, 11...
Rotation axis, 21... optotype, 22... index,
23... Gear, 24... Visual target projection optical axis, 25...
gear.

Claims (1)

[Scope of Claims] 1. A cylindrical component that is added to the eye to be examined by switching and arranging a cylindrical lens on the visual axis of the eye to be examined, or by rotating a cylindrical lens placed on the visual axis around the optical axis. an optical property changing means capable of changing at least one of the cylindrical power and the cylindrical axis; a means for detecting a cylindrical component added to the eye to be examined by the optical property changing means; Occurs when the astigmatism axis test optotype that is visually recognized by the eye, the calculation means for calculating the degree of astigmatism and the astigmatism axis of the eye to be examined, and the arbitrary first cylindrical component of the optical characteristic changing means do not correct the astigmatism of the eye to be examined. an input means for inputting into the calculation means a second composite astigmatism axis generated when a second cylindrical component different from the first composite astigmatism axis and the first cylindrical component is added to the subject's eye; An astigmatism testing device characterized by calculating an astigmatic power and an astigmatism axis of an eye to be examined from each second cylindrical component and each of the first and second synthetic astigmatism axes. 2. The input means shall consist of an index placed on the outer periphery of the optotype for astigmatism axis testing, a moving means for moving the index on the outer periphery, and an input switch for inputting the position of the index moved by the moving means. An astigmatism device according to claim 1, characterized in that: 3. The astigmatism test according to claim 1, wherein the optical characteristic changing means determines the first cylindrical component to be added to the eye to be examined based on a preliminary measurement value by an objective refractometer or a lens meter. Device.