RU201357U1 - Electrode for registration of bioelectrical processes of the retina - Google Patents

Abstract

The utility model relates to medicine, namely to ophthalmology and physiology, and can be used to register bioelectric processes in the retina. The electrode is made of a bowl-shaped form of 585 gold, with a diameter of 8 mm, a radius of curvature of 9 mm, a thickness of 0.3 mm, and the contact (outlet) wire is made with a diameter of 0.07 mm and is located at an angle of 30 degrees on the outer side of the electrode at a distance of 1, 5 mm from the edge. The use of the utility model increases the measurement accuracy due to the optimal parameters of the electrode for its insertion into the retrobulbar space and contact with the retina, and prevents damage to the eye during the study. 2 ill., 1 ex.

Description

The utility model relates to medicine, namely to ophthalmology and physiology, and can be used to register bioelectric processes in the retina.

Electrophysiological studies (electroretinography, electrooculography) make it possible to assess the morphological and functional state of the retina, both in clinical practice and in experiments on biological models.

Despite a fairly large technical and design variety of devices for recording bioelectrical processes of the retina, they all have a single schematic diagram and consist of non-polarizing (weakly polarizing) bioelectric electrodes, a biopotential amplifier (BPA), a power source, an input device and an output device (monitor, oscilloscope , analog-to-digital converter, computer, telemetry systems, etc.).

There are cutaneous, intradermal, corneal and abdominal electrodes for recording bioelectric processes.

As part of the equipment for conducting electrophysiological studies (EPI), at least two electrodes are used, installed in the immediate vicinity of the object under study.

To date, for EPI, as a rule, weakly polarizing contact cutaneous electrodes are used, which are installed at the temple and in the region of the nose. However, in humans, the use of this type of electrodes for recording early morphofunctional changes is hindered by the high resistance of the skin and the relatively large distance from the examined organ, namely the eye. Carrying out such studies in animals is complicated by the fact that the skin of the animals is covered with wool, which makes it impossible to superimpose them.

It is most expedient to place the electrodes as close as possible to the examined organ, in this case to the eye, in order to minimize the loss of the bioelectric signal.

The most suitable for the stated requirements are corneal electrodes with gold coating, which allow registering bioelectric processes in the eye [https://fabrinal.ch/en/products/erg-jet/].

The disadvantages of this type of electrodes include:

1) high probability of loss of electrical contact due to lack of fixation and, therefore, high mobility;

2) disposability, which significantly increases research costs and, accordingly, the final cost of the research for the patient;

3) the need for constant wetting in order to avoid loss of electrical contact.

The closest analogue of the utility model is an electrode for electroretinographic studies, containing a silver-plated conductor with soldering, and the conductor is made of a flexible stranded microwire, one end of which is formed in the form of a loop, and the loop is formed by soldering, closed by an insulating tube that can move along the conductor with slight friction [patent RU No. 35208, 2004].

The task of the utility model is to develop a device for recording bioelectrical processes of the retina with the possibility of intraoperative use.

The technical result when using the utility model is to increase the measurement accuracy due to the optimal parameters of the electrode for its introduction into the retrobulbar space and as close as possible to the retina, preventing damage to the eye during the study.

The utility model is illustrated by the following figures: FIG. 1 shows the proposed electrode, general view; in fig. 2 - an increase in the constant potential of the eye against the background of endovitreal light exposure during the experimental operation.

The proposed electrode 1 for recording bioelectrical processes of the retina has a bowl-shaped shape, weighing 0.4 grams, made of 585 gold, 8 mm in diameter, radius of curvature 9 mm, thickness 0.3 mm. Contact (outlet) wire 2 is made with a diameter of 0.07 mm and is located at an angle of 30 degrees on the outer (opposite contact) side of the electrode at a distance of 1.5 mm from the edge (Fig. 1).

The distinctive features of the utility model provide the following:

1) The electrode is made of 585 gold, which increases the required strength and technical characteristics and, if used together with the corneal electrode, minimizes the effect of the interelectrode resistance on the accuracy of the results.

2) The electrode has the shape of a bowl with a diameter of 8 mm, with a radius of curvature of 9 mm and a thickness of 0.3 mm, these parameters are calculated taking into account the anatomy of the eye and are optimal for insertion into the retrobulbar space and minimize the risk of eye damage during the study. The 8 mm diameter is convenient for insertion into the retrobulbar space and provides optimal contact with the examined organ. A smaller diameter does not allow for optimal contact and leads to distorted results. More than 8 mm - difficult to get into the retrobulbar space, requires a larger incision, which increases the surgical trauma. It has been experimentally established that an electrode with a thickness of 0.3 mm has optimal strength and technical characteristics, an electrode of a smaller thickness is prone to bending, engages in a tenon capsule when installed. With a greater thickness, the electrode is difficult to bring into the retrobulbar space. The radius of curvature of 9 mm is due to the anatomical features of the studied eyes.

3) The contact (outlet) wire is made with a diameter of 0.07 mm and is located at an angle of 30 degrees on the outer side of the electrode at a distance of 1.5 mm from the edge. Such an arrangement was chosen taking into account the peculiarities of the technique of inserting the electrode into the retrobulbar space and minimizes the risk of intraoperative injury, as well as damage to the electrode itself during the study.

4) The electrode is reusable as it allows for disinfection processing.

The proposed electrode is used to register bioelectrical processes of the retina in conjunction with a corneal electrode, for example, Fabrinal ERG-jet (Switzerland). Connect to equipment for electrophysiological research.

Under local anesthesia (epibulbar instillation of 0.4% inocaine solution, retrobulbar injection of lidocaine solution), a conjunctival incision is made in the lower outer quadrant of the eyeball 6-10 mm from the limbus. The conjunctiva and tenon membrane are separated by 10-12 mm towards the posterior pole of the eye. Next, the proposed electrode is inserted into the region of the posterior pole of the eye with atraumatic tweezers. A corneal electrode is placed on the cornea of the examined eye using a contact gel. Both electrodes are connected to a bio-amplifier connected to a power supply and an output device. Next, light stimuli are supplied and changes in bioelectric processes are recorded.

The essence of the utility model is illustrated by the following example.

A rabbit weighing 2.5 kg underwent electrooculography using the proposed electrode. A blepharostat was installed on the rabbit's eye, under local anesthesia (epibulbar instillation of 0.4% inocaine solution, retrobulbar injection of lidocaine solution) 6-10 mm from the limbus, an 8 mm conjunctival incision was made in the inferior-outer quadrant of the eyeball. The conjunctiva and tenon membrane were separated by 10-12 mm towards the posterior pole of the eye. Next, the proposed electrode is inserted into the region of the posterior pole of the eye with atraumatic tweezers. A corneal electrode is installed on the cornea of the eye under study using a contact gel. Both electrodes are connected to a bio-amplifier connected to a power supply and an output device. Next, at a distance of 4 mm from the limbus established 25G port, in which is mounted a light guide illumination system for endovitrealnoy (xenon, 16 cd / m ^2). Lighting duration - 16 minutes. There was an increase in the constant potential of the eye against the background of endovitreal light exposure during the experimental operation, recorded using the proposed electrode (Fig. 2).

Claims (1)

An electrode for recording bioelectrical processes of the retina, containing a conductor made of precious metal and a contact wire made of copper, characterized in that the conductor is made of a bowl-shaped form of 585 gold, with a diameter of 8 mm, a radius of curvature of 9 mm, and a thickness of 0.3 mm , and the contact wire is made with a diameter of 0.07 mm and is located at an angle of 30 degrees on the outer side of the electrode at a distance of 1.5 mm from the edge.

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