RU95983U1 - ELECTRORETINOGRAM DEVICE - Google Patents

Abstract

 1. A device for the removal of electroretinograms containing a ring electrode-suction cup, the body of which is made in the form of a glass with an electrode installed on its working end for removing the electroretinogram, and a light stimulator with a light source is installed on the opposite end, characterized in that the differential electrode is mounted on the electrode body a preamplifier with a high input impedance and a low output impedance, made in the form of a microchip, designed to pre-amplify the output potential a, and the positive input of the preamplifier is connected to the ring electrode. ! 2. The device according to claim 1, characterized in that the microchip is made using nanotechnology. ! 3. The device according to claim 1, characterized in that a multicolor LED is used as the light source.

Description

The utility model is intended for use in medicine more precisely in ophthalmology and can be used to divert the total and local electroretinogram - ERG. In addition to the psychophysical methods for studying eye diseases, the clinic widely uses electrophysiological methods, including electroretinography.

Electroretinography is used to quantify the functional state of retinal neurons, to localize the pathological process of the eye.

ERG is a graphical representation of changes in the bioelectrical activity of retinal neurons in response to light stimulation (see, for example, A.M. Shamshinova, VV Volkov. Functional research methods in ophthalmology. Moscow, “Medicine”, 1998. p. 415).

There are several types of electroretinograms:

a) general or Ganz - feld (Ganz-Feld) ERG, is recorded provided that the entire field of the retina is uniformly illuminated.

b) zonal ERG - recorded during stimulation of individual zones of the retina;

c) local ERG - is recorded during stimulation of a local site in one of the zones of the retina. Local ERG; registered from the macular region of the retina, called macular ERG or MERG;

d) flickering ERG or rhythmic ERG (RERG) is recorded by flickering stimuli with different repetition rates.

Zonal - ERG is usually recorded from three areas of the retina: central (macular), paracentral (paramacular) and peripheral.

General - ERG has two main waves: “a”, arising after 30 ms. after the stimulus with an amplitude of 40 μV, and the wave "b" with an amplitude of 250-300 μV, arising at 80 ms. after the stimulus.

When registering a local (macular) ERG, under normal conditions of abduction, of a healthy patient, at a stimulus of 18 °, the amplitude of the response “a” of the wave does not exceed 5 μV, which is comparable to the level of interference arising from jitter of conductors from the electrodes to the amplifier.

The discharge (active) electrodes for registering ERG used in the clinic are contact lenses with a large opening of the optical zone of the cornea and various types of hooks and hairs. At present, electrodes - suction cups for the removal of the total and local - ERG have become widely used (see, for example, Shamshinova AM, Govardovsky V.I., Golubtsov K.V. “On the method of recording local ERG”, West Ophthalmology, 1989, No. 6, p. 47-49).

One of the significant problems in the removal of electroretinograms is artifacts in the form of slow oscillations associated with the trembling of the lead conductors coming from the electrodes to the biopotential amplifier, often at the level of the useful signal amplitude. In this regard, the method of averaging (summing) of electrical responses to a flash of light is widely used. Typically, when registering a total ERG, averaging of 8-10 reactions is used, and when registering a local (macular) ERG, more than 40 averages are used.

Normally, in a healthy patient, the amplitude of the response to light stimulation “a” - ERG waves does not exceed 20 μV, (see, for example, Shamshinova AM “Local ERG in the clinic of eye diseases: Guidelines, Moscow, 1991, p.24) . In case of retinal disease, the amplitude of the “a” wave does not exceed 3 μV, which is comparable to the artifact from the vibration of the conductors from the electrode to the biopotential amplifier.

Known devices with electrodes - suction cups (or electrodes-amplifiers) for the removal of ERG (see, for example: SU No. 1402337, authors: Golubtsov K.V., Govardovsky V.I., Shamshinova AM; SU No. 1554890, authors: Shamshinova AM, Govardovsky Golubtsov K.V. et al .; RU No. 2225157, authors: Golubtsov K.V. Milekhin Yu.M., Bubra AM, Goncharov V.I., Shamshinova AM, etc.).

A device is known, taken as a prototype (RU No. 83692, author: Golubtsov K.V.) for the removal of a local electroretinogram, containing a ring electrode-suction cup, the body of which is made in the form of a glass with an electrode for removing the electroretinogram installed on its working end, and on the opposite end mounted light stimulator with a light source.

A common drawback of these devices is artifacts in the form of slow oscillations associated with the vibration of the lead-out conductors coming from the electrodes to the biopotential amplifier, which can exceed the biopotential and network pick-ups with a frequency of 50 Hz.

The purpose of the utility model is to create an electrode - a suction cup that allows you to level artifacts associated with trembling of the conductors.

This goal is achieved by the fact that on the electrode body, a differential preamplifier with a high input impedance and low output impedance, made in the form of a microchip, is designed to pre-amplify the output potential, the positive preamplifier input connected to the ring electrode, and the gain should be at least 10.

In this device, a micro-chip can be manufactured using nanotechnology, and a multicolor LED can be used as a light source,

A preamplifier in the form of a micro - chip is mounted directly on the electrode - suction cup. The microchip is a differential preamplifier with high input impedance and low output. Such micro - chips, whose weight does not exceed ~ 7-9 mg, do not burden the electrode - suction cup, since the total weight of the electrode - suction cup is several grams.

The preamp gain must be at least 10.

Figure 1 presents the block diagram of the electrode with a chip.

Figure 2 presents a General view of the electrode assembly. In this embodiment, the 741 series op-amp was used as a micro-chip.

Claims (3)

1. A device for the removal of electroretinograms containing a ring electrode-suction cup, the body of which is made in the form of a glass with an electrode installed on its working end for removing the electroretinogram, and a light stimulator with a light source is installed on the opposite end, characterized in that the differential electrode is mounted on the electrode body a preamplifier with a high input impedance and a low output impedance, made in the form of a microchip, designed to pre-amplify the output potential a, and the positive input of the preamplifier is connected to the ring electrode. 2. The device according to claim 1, characterized in that the microchip is made using nanotechnology. 3. The device according to claim 1, characterized in that a multicolor LED is used as the light source.