JPH0323047B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an electroretinometer equipped with an automatic flash mechanism, and more particularly to a retinal potential measuring device that can perform measurements easily and can be operated effectively.

(Prior art) A human or animal eyeball usually has a resting potential that is (+) on the cornea side and (-) on the posterior pole side. It is known that the light changes the moment it hits you and the moment it disappears.

This phenomenon is widely used in inspections, research, etc., and for example, the so-called ERG is a record of such potential fluctuations with time as the horizontal axis.
(Electroretinogram), which captures action potentials in the retina. For this reason, ERG is the most widely used electrophysiological test for retina or vision, and the ERG is characterized in that the eyeball potential fluctuation is an objective response, for example, It is an effective testing method for retinal function tests when the fundus cannot be seen through due to opacity of the transparent body, and for diagnosing retinochoroidal diseases.
Widely used.

By the way, as an effective method for deriving the action potentials that are generated widely in the retina in response to the above-mentioned light stimulation, the method is usually to use electrodes (electrode) that are brought into direct or indirect contact with the corneal surface of the eyeball. )of,
A method is adopted in which the potential difference is detected and measured with respect to an electrode (indifferent electrode) whose potential is set to 0 by contacting the forehead or the like.

In such a retinal potential measurement, with the subject wearing a predetermined electrode, the examiner, for example, while observing the monitor, confirms that the noise level has stabilized, and at that point, By applying a flash (light) stimulus to the subject's eyes,
The ERG waveform is obtained. In order to confirm the noise level at this time, a method is generally adopted in which the examiner is informed of the noise information by the amplitude of a bright spot on the monitor screen.

In addition to the so-called external noise that exists inside the measuring device itself or that originates from sources other than the device, such noise may also be generated from the subject's eye movements or improper attachment of contact lens electrodes. Although there is noise, in order to obtain a good ERG waveform, it is important to perform measurements with as little noise as possible.

In addition, as another method of noise monitoring, a noise observation method using a level meter incorporating a large number of light emitting diodes has been proposed, but in the same way as above, after the examiner judges the noise information using the level meter, In order to stimulate the flash, you press the start button,
Whether or not the noise level had stabilized had to be determined by the examiner.

(Problems) However, with regard to the flash mechanism of the conventional electroretinometer as described above, since the operation is based on the subjective judgment of the examiner, there are many inherent problems that cannot be avoided. It was.
In other words, when operating the strobe to provide such a flash stimulus, the examiner must continue to monitor the monitor, and therefore the examiner must keep an eye on the subject's fixation state, contact lens electrode attachment status, etc. immediately before the test. This makes it difficult to monitor or observe the condition of the subject. As mentioned above, in order to obtain an effective ERG waveform, this is done in order to have the examinee fixate on the fixation lamp installed in the stropo so that the examinee suppresses eye movements as much as possible. This is because people always need to be careful. Of course, if the contact lens electrode is dislodged or floating from the cornea, the test will fail. As described above, conventional corneal potential measurements have always had the problem that it is difficult for the examiner to observe the subject.

Furthermore, the task of having the examiner judge noise information from the monitor and quickly press the start button (slush stimulus) requires skill on the part of the examiner, and may sometimes lead to measurement failure. This is said to be mainly caused by noise caused by human eye movements, but since eye movements are unstable and irregular, the noise information on the monitor is also extremely irregular. This is because, especially when performing binocular measurements, it is extremely difficult to capture the moment when the noise in the left and right eyes enters the stable range at the same time and press a button or the like.

(Solution Means) Here, the present invention has been made against the background of the above, and in order to solve all the problems in the conventional art, the present invention has been developed in an electroretinometer for measuring retinal potential. an amplification means for amplifying the retinal potential; a noise detection means for detecting noise from the amplified retinal potential; and a determination as to whether or not the amount of noise detected by the noise detection means is below a predetermined set value. a first determining means; a second determining means for determining whether or not the amount of noise remains below a predetermined set value for a predetermined time or more; There is provided an electroretinometer equipped with an automatic flash mechanism, characterized in that it has means for automatically applying a flash stimulus when the flash stimulus is present and maintained for a predetermined period of time or longer.

(Operation/Effect) In other words, the present invention does not use the examiner's subjective judgment to determine noise information before electroretinography measurement, but instead sets a predetermined amount of noise (noise level) within the ERG measuring device. The device is designed to automatically apply flash (light) stimulation after maintaining the permissible range for a certain period of time, allowing the examiner to attach the electrodes to the subject. After completing the necessary preparations for the test, simply press the start button, and the above-mentioned automatic flushing mechanism according to the present invention will function, making it possible to provide effective ERG waveforms more easily than before. It was.

That is, according to the present invention, the measurement of retinal potential becomes extremely simple, and the examiner can observe the condition of the subject at all times, improving measurement accuracy and It is now possible to prevent measurement failures due to improper installation of the sensor, and the noise level can be set.
It is easy to obtain a good ERG waveform with little noise, and furthermore, the examiner's subjective judgment regarding noise information can be eliminated, making it possible to improve the reproducibility of the ERG waveform.

(Example) Hereinafter, in order to clarify the present invention more specifically, examples according to the present invention will be described in detail based on the drawings.

First, FIG. 1 shows an example of an electroretinometer according to the present invention, in which 1 is a main body of the device, and a flash box 2 is provided on the side of the main body 1. Inside the flash box 2, a U-shaped xenon lamp 3 is provided for applying flash (light) stimulation. A fixation light 4 for fixation is provided. This fixation lamp 4 has the purpose of stopping the movement of the subject's eyes by gazing at it and preventing the generation of noise. Since it is carried out in the dark, a high-intensity LED whose brightness can be changed is used to facilitate the attachment of electrodes to the subject and can also be used for verification purposes. . In addition, as is well known, the subject is fitted with indifferent electrodes 6 such as contact lens electrodes on the left and right eyes, an indifferent electrode 7 on the forehead, etc., and a grounding electrode. Ear electrodes 8 are attached, and the target retinal potential is measured, for example, in a supine position as shown. In addition,
Each electrode 6, 7, 8 is connected to a predetermined terminal of the device main body 1, respectively.

Further, the operation unit 5 provided on the side of the apparatus main body 1 of such an electroretinometer displays the fixation state (including noise) of the subject, as shown in an enlarged view in FIG. 2, for example. Fixation monitor 9, start button 1 that applies a flash stimulus when switching to manual operation and activates the automatic flash mechanism when switching to automatic operation
0, a switching button 11 for switching between automatic operation and manual operation, a paper feed button 12 for feeding paper in a printer that records retinal potential, and a lighting button 13 for changing the brightness of the fixation lamp 4 and for illumination. have. When the automatic/manual change button 11 is pressed to select automatic operation, the automatic flush mechanism according to the present invention is activated by pressing the start button 10.
After waiting for the noise level to stabilize in the retinal potential collected based on the input from each electrode 6, 7, and 8, the xenon lamp 3 is automatically flashed to obtain the desired ERG waveform. be.

In addition, with this electroretinometer, it is also possible to perform measurements based on the examiner's judgment of noise information, as in the past, and in that case, the automatic/manual switching button 11 allows for manual It is also possible to select the operation side and operate the start button 10 based on the examiner's subjective judgment while looking at the fixation monitor 9 to give a flash stimulus to the examinee. In addition, this fixation monitor 9 does not use a cathode ray tube like the conventional ones, but instead uses a lamp display that blinks in response to a predetermined amount of noise, making it simpler, cheaper, and lighter than conventional monitors. .

By the way, the device body 1 of such a retinometer
Contained therein is a mechanism for implementing the block diagram of an electroretinometer as shown in FIG. 3, incorporating an automatic flashing mechanism according to the present invention. There, each electrode 6, 7, 8 attached to the subject as shown in FIG. 1 is connected to the electrode connection terminal 20, and the retina taken out by these electrodes 6, 7, 8 is In the case of binocular measurement, the potential is transmitted from the left and right isolation amplifiers 22a and 22b to the respective amplifiers 2.
4a, 24b, or in the case of one-eye measurement,
From either isolation amplifier 22a or 22b, via the corresponding amplifier 24a or 24b, the left and right channels (left and right eyes)
After passing through a switch 26 and an AD converter 28, and being processed by a microcomputer 30, the ERG waveform is automatically recorded by a printer 32 such as a thermal dot printer.

Note that the isolation amplifiers 22a and 22b of each channel (each eye) are for amplifying the noise to a certain extent, leaving the necessary waveform parts (limiting the same fractional area), and amplifying the noise to a certain extent. With amplifiers 24a and 24b after amplifying over
It constitutes an amplification means for amplifying the extracted retinal potential, and also includes amplifiers 24a and 2 of each channel.
The output from 4b is inputted to the input monitors 34a and 34b of the corresponding channels, and is also inputted to the left and right channel changeover switch 26, where it is inputted to the left and right channel changeover switch 26, and there, It is possible to selectively switch between three types of retinal potential measurements.

And the automatic flash circuit according to the present invention is
Left and right noise detection circuits 36a, 36b, time setting circuit 38, and flash signal trigger output section 40
It is composed of. There, the output from the amplifiers 24a and 24b of each channel is
Left and right noise detection circuits 36a and 36b, respectively.
There, noise is detected from the retinal potentials of the left and right eyes, and it is determined whether the amount of detected noise is less than a predetermined set value. Next, the signals outputted from the detection circuits 36a and 36b are adjusted to a predetermined value based on a predetermined time, which is preset in the time setting circuit 38, during which the amount of noise (noise level) is below a predetermined set value. If the amount of noise is below a predetermined set value and is maintained for a predetermined time or longer, a predetermined signal is output from the time setting circuit 38, and the signal is Based on the flash signal trigger output section 40, the microcomputer 30
A flash signal is output to the microcomputer 30.
The light emitting section (xenon lamp 3) will be flashed.

Note that here, the left and right noise detection circuits 36
a, 36b are left and right channel amplifiers 24a,
It functions as a noise detection means for detecting noise from the retinal potential amplified by 24b, and the amount of noise (noise level) detected there is determined by a predetermined setting value (threshold value) set with a resistor or the like, e.g.
It is configured to also function as a first determining means for determining whether or not the voltage is 50 μV or less, and the time period during which the amount of noise is equal to or less than a predetermined set value determined by the detection circuits 36a and 36b is The time setting circuit 38, which is the second determining means, determines whether or not it has been maintained for a predetermined period of time or more. In addition, when the noise amount is below a predetermined set value and maintained for a predetermined time or more by a signal from the time setting circuit 38, the means for automatically applying a flash stimulus is here a flash signal trigger output. Part 40
It is composed of a microcomputer 30 and a light emitting section 3.

In addition, in the mechanism shown in Fig. 3, power is supplied to the light emitting unit 3 and each circuit power supply, etc., either directly or indirectly through the DC-DC converter 44, etc., by the DC power supply 42 replaced from AC100V. It's getting old.

Incidentally, FIG. 4 shows the details of the above-mentioned automatic flushing mechanism in the form of a flowchart. FIG. 4 shows the examiner pressing the start button 10 after preparations for measurement of the subject have been completed. First, the amount of noise entering the left and right channel amplifiers from the electrodes attached to the subject is measured by the noise detection section, and if the amount is less than a set value, the fixation monitor is turned on. The fixation monitor lights up in both eyes,
When this is maintained for a predetermined period of time, a signal for flash stimulation is output, and the rest is similar to conventional methods, in which the strobe (xenon lamp 3) flashes to give flash stimulation to the subject, detects ERG, and automatically Measure (print out). Although FIG. 4 is a flowchart for binocular measurement, the flowchart is the same for monocular measurement.

Through such operations, action potentials generated in the retina can be presented to the examiner in a very simple manner. In addition, compared to conventional strobe operation that requires skill, the examiner simply presses the start button, and the automatic flash mechanism according to the present invention in the device is activated, allowing ERG waveforms to be obtained automatically and with fewer failures. It became.

Although the embodiments of the present invention have been described in detail above, it goes without saying that the present invention is not to be construed as being limited only to such illustrative specific examples. Unless otherwise specified, it should be understood that the present invention may be implemented in forms with various modifications, modifications, improvements, etc., and that the present invention includes such embodiments.

For example, in the above-mentioned specific example, although the fixation monitor as a noise monitor is not essential in the present invention, it can be turned on even when an automatic flash operation is performed as in the present invention. This has the advantage that noise information is easy to understand.

Further, in the above example, each detection circuit 36a, 36b
Although the first judgment means for judging the noise amount may be provided separately from such a detection circuit, there is no problem. It is also possible to have the first judgment means and the second judgment means serve as both. In addition, the setting value (threshold value) for determining the amount of noise
In addition to being fixedly set using a resistor, etc., as shown in the example, it is also possible to make it variably adjustable using a suitable setting device, and such a set value is usually approximately 50 μV. It will be set to a certain degree.

Furthermore, the set value by the time setting circuit 38 etc. for the determination time of the amount of noise that is less than or equal to the set value is as follows:
It is possible to set it fixedly, but it can also be variably adjusted in stages.It is usually set in the range of approximately 0.1 seconds to 1 second, and during that set time, a predetermined period of time is set. The second determining means determines whether or not the amount of noise is maintained below the set value.

Furthermore, it goes without saying that the automatic flushing mechanism according to the present invention can be constructed not only in hardware as in the above example, but also in software.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of an electroretinometer according to the present invention, FIG. 2 is an enlarged explanatory diagram of an operating section in such an electroretinometer, and FIG. 3 is a schematic diagram showing an example of an electroretinometer according to the present invention. FIG. 4 is a flowchart showing the operation of the automatic flash mechanism in such an electroretinometer. 1: Device body, 2: Flash box, 3:
Xenon lamp, 4: Fixation lamp, 5: Operation unit, 6:
Related electrode, 7: Indifferent electrode, 8: Ear electrode, 9: Fixation monitor, 10: Start button, 11: Automatic/manual switching button, 12: Paper feed button, 13: Lighting button, 20: Electrode connection terminal, 22a, 22b: isolation amplifier, 24a, 24b: amplifier, 26: left/right channel changeover switch, 30: microcomputer, 32: printer, 34a, 34b: input monitor, 36a, 36b: noise detection circuit, 38:
Time setting circuit, 40: Flash signal trigger output section.

Claims (1)

[Claims] 1. In an electroretinometer for measuring retinal potential, an amplifying means for amplifying the retrieved retinal potential, a noise detecting means for detecting noise from the amplified retinal potential, and a noise detected by the noise detecting means. a first determining means for determining whether the amount of noise has become below a predetermined set value; and a second determining means for determining whether the amount of noise has been below the predetermined set value for a predetermined time or longer. and means for automatically applying a flash stimulus when the amount of noise is below a predetermined set value and maintained for a predetermined time or longer. Electroretinometer.