RU2668462C1 - Method of investigation of field of vision and device for implementation thereof - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: claimed group of inventions refers to the field of medicine, namely, to ophthalmology. To investigate the field of vision, light stimuli are provided by light sources of a hemispherical screen mounted on the cornea. In this case, the zero reference point of the angular coordinates of the non-centrality of the stimuli presented is determined by the method of successive approximation of the location of the latching stimulus to the visual axis. Zero semimeridian of the surveyed field of view for reading the meridian angle of the stimuli presented is determined from the zero reference point relative to the physical horizon or relative to the line passing through the centers of the pupils of both eyes of the examined patient. In this case, the device for studying the field of view contains a hemispherical screen with light sources for the presentation of light stimuli, a control and registration unit, motion/position sensor for monitoring the motion and position of the screen, transmitters and receivers for wireless communication of the control unit with the screen.EFFECT: group of inventions increases the reliability of the results of the study by eliminating the dependence of the results of the study on the movements of the eye and on the accuracy of controlling the fixation of the sight at fixation points.4 cl, 5 dwg

Description

The invention relates to medicine, in particular to ophthalmology, namely to perimetry for the subjective detection of the presence of a test stimulus and can be used for early diagnosis of primary glaucoma and other diseases that limit the field of view of the human eye.

To study the visual field, perimetry is used - a method in which the photosensitivity of various parts of the retina is studied by projecting visual stimuli on them and recording the patient's response to the presented stimulus.

A traditional study is conducted as follows:

- the gaze of the examined eye is fixed at the fixation point and should be fixed during the entire study;

- visual stimuli are presented alternately at different angular coordinates relative to the visual line;

- the patient responds to the presentation of incentives, for example, by pressing the “see” button, gesture or voice;

- the patient's response is recorded and then interpreted.

When examining the visual field in this way, an important factor is the control of fixing the gaze at the fixation point. The accuracy of determining the coordinates of the projection of the stimulus onto the retina of the eye and, accordingly, the accuracy and reliability of the research results depend on the accuracy of control of the position of the pupil.

The well-known perimeters (AP-1000 from Tomey, Centerfield 2 from Oculus, Galaxy from MS Westfalia GmbH and others) use two main methods of controlling gaze fixation at the fixation point: the Heijl-Krakau method (periodic presentation of visual stimuli to the blind spot) and using a camcorder.

The main disadvantage of the Heijl-Krakau method is its low accuracy, which is explained by the large size of the blind spot (normally, approximately 6 by 8 °), which, when projecting a stimulus of 0.43 ° in size (III according to Goldman), gives an error in determining the coordinates unacceptable according to the requirements of ISO 12866.99.

A more accurate way to control using a camcorder. But he also has a drawback. Due to the fact that the visual line (visual axis, axis of fixation) [http://dic.academic.ru/dic.nsf/enc_medicine/12199/%D0%97%D1%80%D0%B8%D1%82 % D0% B5% D0% BB% D1% 8C% D0% BD% D0% B0% D1% 8F] does not match the optical axis of the eye [http://medbe.ru/materials/obshchee-v-oftalmologii/ponvatie- o-klinicheskov-refraktsii] and in different people, this deviation has different meanings, it is impossible to control the position of the pupil by its geometric parameters, even by placing the camera on the optical axis of the perimeter.

The technical problem is that the control (measurement) of the position of the pupil can be carried out only relative to some initial position of the eye, and the initial (zero) coordinates are fixed at the moment when the operator believes that the gaze is fixed at the fixation point, i.e. there is a subjective component. Given that the eye is in constant involuntary movement (drift, saccades, etc.), it is very difficult to establish such a moment, because today there is no objective method to determine exactly whether the eye is currently looking at the fixation point or not.

The problem is aggravated in the methods of studying the field of view using the fixation point presented at different coordinates relative to the optical axis of the perimeter. For example, with a "driver" test, with offset fixation points. In this case, it is necessary either to determine the moment of coincidence of the visual line with each new fixation point and fix this position of the eye as a base, or measure and control the angle of rotation of the eye relative to the position recorded as basic, with the gaze fixed on the fixation point located, for example, on the optical axis of the perimeter. But video cameras and other motion sensors will not provide the necessary accuracy in determining the angle of rotation of the eye due to the large list of physiological characteristics of the eye [http://zreni.ru/2061-dvizheniva-glaz-9474-chast-1.html].

As the closest analogues to the claimed solutions, the traditional method of perimetry is selected [http://www.medicalj.ru/diacrisis/oftalmologiva/878-perimetriva, http://www.setchtka-glaza.ru/perimetriya-issledovanie-i-opredelenie -poleyzreniya /], when the patient’s gaze is fixed at the fixation point throughout the study, visual stimuli are presented alternately at different angular coordinates relative to the visual line, the patient responds to the presentation of stimuli, the patient’s response is recorded and interpreted, and the Centerfield-2 computer perimeter [http: //www.dealmed.ru/centerfield-2.html], consisting of a hemispherical screen with light sources for the presentation of the light stimulus unit and the control and registration.

The disadvantages of this method and the Centerfield-2 perimeter are the insufficient quality and reliability of the information obtained by examining the patient’s field of view, which ultimately reduces the quality of early diagnosis of various eye diseases, including early glaucoma. This is because in the indicated method and device, the reliability of the research results largely depends on the accuracy of the control of fixing the gaze at the fixation point, a high degree of which is impossible for the above reasons.

The result, the claimed solutions are aimed at achieving, is to increase the reliability of the research results by eliminating the dependence of the research results on eye movements and on the accuracy of the control of fixing the gaze at the fixation points.

The specified result is achieved by the fact that the claimed method of studying the visual field is carried out by presenting light stimuli (with registration and subsequent interpretation of the response of the examined patient to presenting stimuli) using light sources of a hemispherical screen mounted on the cornea, while the zero point of reference is the angular coordinates of off-center (eccentricity) ) of the presented stimuli is determined by the method of successive approximation of the location of the presented fixation (zero) stimulus to the visual axis, zero half-meridian of the examined field of view for counting the meridian angle (azimuth) of the presented stimuli is determined from the zero reference point relative to the physical horizon or relative to the line passing through the centers of the pupils of both eyes of the examined patient, and the claimed device contains a hemispherical screen with light sources for presentation of light stimuli, control and registration unit, motion / position sensor for monitoring movement and screen position, transmitters and reception nicknames for wireless communication of the control and registration unit with a hemispherical screen, and a hemispherical screen is made for installation on the cornea of the eye and is opaque.

Light sources can be realized using micro-LEDs with micro lenses or using micro lasers [http://tech-life.org/technologies/485-contact-lens].

The motion / position sensor of the screen can be external, for example, optical (as an option - a video camera), or integrated into the screen (electronic accelerometer, gyroscope, magnetometer).

There are technologies that allow the manufacture of the inventive device in the near future. First of all, this is the work of Babak Parviz [http://tech-life.org/technologies/485-contact-lens]. Also, LEDs the size of a molecule have been developed [http://www.sciencedebate2008.com/the-world-smallest-leds/, https://www.popmech.ru/science/15436-samyy-malenkiy-v-mire-svetodiod /] and ultra-thin microcircuits [https://hi-tech.mail.ru/news/molekula-chip/]; there are TOLED and FOLED technologies [http://ledjournal.info/byt/oled.html] that allow you to make screens of any shape; contact lenses with integrated microcircuits were created [http://batona.net/70608-faktv-o-kontaktnyh-linzah.html], which confirms the possibility of manufacturing complex optoelectronic devices in small dimensions; various technologies for wireless power supply of electronic devices and numerous wireless methods for controlling and transmitting information have long been known and are developing; resolved the issue of focusing the eye on the image, which is formed practically on its (eyes) surface [http://tech-life.org/technologies/485-contact-lens, http://www.linzshop.ru/news/kontaktnye-linzy -buduwego-smogut-proecirovat-izobrazhenie-na-setchatku-glaza.html, http://www.bbc.com/russian/science/2011/11/111122_biolenses_email].

At the same time, the practical implementation of the claimed device is much simpler than the task of creating “smart” contact lenses (contact lenses with augmented reality, bionic contact lenses, etc.). Firstly, a hemispherical screen with light sources for presenting light stimuli of the claimed device should be opaque, and this allows you to use its entire area (and if there is not enough space, make it multilayer) and place all the necessary components on it: light stimulus sources, background illumination, control circuit, various sensors, receiver, transmitter, antenna, etc. Secondly, in contrast to contact lenses that need to be worn for a long time, a hemispherical screen with light sources for presentation of light stimuli of the claimed device is installed on the cornea only for research, for 5 ... 20 minutes, i.e. biosafety requirements for materials in contact with the eye will be less stringent. Less stringent will be the requirements for temperature conditions of the elements entering the screen. Third, transmitters and

the receivers associated with the control and registration unit can be installed in the immediate vicinity of the hemispherical screen receivers and transmitters (close to the examined eye), for example, on a spectacle frame, and this will minimize the power of the transmitters used, which is especially important for wireless power supply technologies.

Embodiments of the inventive device are shown in FIG. one.

Option 1 (Fig. 1A) includes the following elements: control and registration unit 1; hemispherical screen 2 with light sources for presenting light stimuli and integrated into it (on the screen) control circuit 3 of light sources, a motion / position sensor 4 that controls the movement of the screen relative to the patient’s head and the position of the screen relative to the physical horizon, receiver 5 for wireless reception of control commands from the control and registration unit 1, the transmitter 6 for wireless data transmission from the motion / position sensor 4, the receiver and the antenna of the wireless power 7; a receiver 8 for wirelessly receiving data from a transmitter 6; a transmitter 9 for wireless transmission of control commands from the control unit and registration 1 to the receiver 5; Wireless transmitter and antenna 10.

Option 2 (Fig. 1B) includes the following elements: control unit and registration 1; a hemispherical screen 2 with light sources for presenting light stimuli with an integrated light source control circuit 3, a receiver 5 for wirelessly receiving control commands from the control and registration unit 1, a receiver and an antenna for wireless power 7; a transmitter 9 for wireless transmission of control commands from the control unit and registration 1 to the receiver of control commands 5; transmitter and antenna for wireless power 10; motion / position sensor 12, configured to optically (visually) monitor the movement of the screen relative to the head and the position of the screen relative to the physical horizon or relative to the line passing through the centers of the pupils of both eyes of the patient, by the movement and position of the visual marks on the outer surface of the hemispherical screen 2 (FIG. . H): central 11, by the movement of which the zero reference point is determined, and radial 13, by the position of which the zero half-meridian is determined.

The study of the field of view using the proposed method and the claimed device can be carried out as follows:

- a hemispherical screen 2 (Fig. 2), close in size and shape to the size and shape of contact lenses, is mounted on the cornea of the eye so that the center of the screen approximately coincides with the center of the pupil, and the visual radial mark 13 (in the case of the implementation of the device according to the embodiment 2) approximately coincided with the zero half-meridian of the examined field of view;

- presented with a light stimulus 14 (Fig. 2A) located on the axis of the screen;

- the patient is instructed to fix his gaze on the presented stimulus;

- if the presented stimulus 14 is located not on the visual axis 15, then an attempt to focus on it (to project the stimulus on the central fossa of the retina) will lead to the movement (rotation) of the eyeball and, accordingly, to the movement of the screen 2 mounted on the cornea (for the patient - to the movement of the stimulus presented on the screen: the light stimulus will “run away” from the view);

- the motion / position sensor 4 or 12 will detect the movement of the screen 2, and information about this will go to the control and registration unit 1 from the motion / position sensor 4 through the transmitter 6 and receiver 8, or directly from the motion / position sensor 12;

- after which, by means of the control and registration unit 1 and the control circuit of the light sources 3 connected through the transmitter 9 and receiver 5, the next presented stimulus will be moved in the opposite direction to the movement of the screen (eyes); the motion / position sensor will detect the next shift, and the control and registration unit will correct the location of the presentation of the next stimulus. By the method of successive approximation, the correction of the location of the presented fixation (zero) stimulus to the visual axis will continue until the movement of the screen mounted on the cornea ceases;

- at the moment of completion of the correction, the movement of the screen (eye) will stop (the next stimulus will not “run away” when trying to focus on it), which corresponds to finding the presented light stimulus on the visual axis 15 (Fig. 2b), and its location can be considered a zero reference point angular coordinates of off-center (eccentricity) of other presented stimuli in accordance with the research program;

- the zero half-meridian of the examined field of view for reading the meridian angle (azimuth) is determined from the zero reference point automatically, for example, by any of the following methods:

1) using the motion / position sensor 4 integrated into the screen 2, by measuring the angle of inclination 16 of the horizon 17 of the motion sensor / position 4 relative to the physical horizon 19 and taking this angle into account when determining the zero half-meridian of the studied field of view (Fig. 3);

2) using a motion / position sensor 12, the horizon of which is tied to the physical horizon 19 (Fig. 4), or (in the case of examination of a lying patient) - to line 20 parallel to line 21 passing through the middle of the pupils of both eyes (Fig. 5 ), according to the visual radial mark 13 (Fig. 4) located on the outside of the screen; while the motion / position sensor 12 measures the angle of inclination 16 of the visual radial mark 13 relative to its horizon and takes this angle into account when determining the zero half-meridian of the studied field of view;

- the set zero reference point and zero half-meridian of the studied field of view are stored by the control and registration unit as such for determining the coordinates of the presentation of stimuli according to the research program;

- further, the study is carried out according to the method generally accepted for perimetry: by a command from the control and registration unit 1 through the transmitter 9, receiver 5 and control circuit 3, the light sources on screen 2 present light stimuli with parameters (coordinates, brightness, color, sizes) specified by the program research. Upon detection (identification) of the presented stimulus, the patient responds to its presentation, and the patient's response is recorded by the registration and control unit 1, for example: as a result of the patient's independent action through any manipulator (button, sensor, keyboard, trackball, computer “mouse”, etc. e.) of the registration and control unit 1, or as a result of the actions of a doctor-operator through any manipulator (button, sensor, keyboard, trackball, computer mouse, etc.) of the registration and control unit 1 by gesture or by voice the patient’s response to the presented stimulus. The obtained results of the presentation of all stimuli according to the research program are recorded (recorded, stored) by the registration and control unit 1 and then interpreted.

When conducting perimetry by the claimed method and using the inventive device, there will be no need to constantly, throughout the procedure, fix the eye on the fixation object and it will not be necessary to control the accuracy of this fixation; motion / position sensor 4 or 12, transmitter 6 and receiver 8 will only be used to determine the zero reference point and zero half-meridian, after which during the examination of the visual field, the examined eye and the patient’s head can move, the patient can be in any position comfortable for him and even blink. To completely exclude the influence of external visual stimuli, the study can be carried out with eyes closed and / or with a blindfold.

Thus, the claimed solution allows you to:

- eliminate the error in the results of the study of the field of view associated with the continuous movement of the eye and the inability to determine the exact location (relative to the visual line) of the presented stimulus at the time of its presentation;

- reduce patient fatigue during perimetry by eliminating the need to be in a fixed (and often uncomfortable) position and the need to constantly fix the gaze on the fixation point;

- conduct research outside specially equipped rooms;

- conduct a study of bedridden patients.

The above makes it possible to conduct perimetry at a qualitatively new level and increases the accuracy and reliability of the results of the study of the visual field.

Claims (4)

1. The method of studying the visual field by presenting light stimuli, recording and interpreting the response of the examined patient to presenting stimuli, characterized in that the light stimuli are presented using light sources of a hemispherical screen mounted on the cornea, a zero point of reference for the angular coordinates of the off-center (eccentricity) of the presented stimuli determined by the method of successive approximation of the location of the presented fixation (zero) stimulus to the visual axis, and zero by the lumeridian of the examined field of view for counting the meridian angle (azimuth) of the presented stimuli is determined from the zero reference point relative to the physical horizon or relative to the line passing through the centers of the pupils of both eyes of the examined patient. 2. A device for studying the field of view containing a hemispherical screen with light sources for presenting light stimuli, a control and registration unit, characterized in that it contains a motion / position sensor for monitoring movement and position of the screen, transmitters and receivers for wireless communication of the control and registration unit with a hemispherical screen made for installation on the cornea of the eye and opaque. 3. The device according to claim 2, characterized in that the motion / position sensor is integrated into the hemispherical screen and is configured to monitor the movement of the screen relative to the patient’s head and the position of the screen relative to the physical horizon. 4. The device according to p. 2, characterized in that the motion / position sensor is configured to optically (visually) control the movement of the screen relative to the patient’s head and the position of the screen relative to the physical horizon or relative to the line passing through the centers of the pupils of both eyes of the patient being examined, by movement and the position of the visual marks on the outer surface of the hemispherical screen.

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