RU2420223C2 - Device for visual field examination - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine. Device contains a case, in whose cavity installed is a perforated sphere sector, with placed in perforation holes light point test-objects for demonstrating to patient and fixation light test-object, located on the central axis of the perforated sector. In the case, which is provided with a handle, there is an inspection window, and light point test-objects and fixation light test-object are connected with the unit of power supply, control and registration. The device is provided with demonstration screen, facing the internal surface of the perforated sphere sector, axisymmetric with it and copying its form; at least, one additional fixation light test-object, located in the perforated sphere sector, displaced from the central axis of the demonstration screen; means of the demonstration screen illumination, placed on the internal part of the case on the ring-shaped printed circuit plate and facing the demonstration screen. The demonstration screen is made from material which passes, at least, partially, irradiation of light point test-objects and fixation light test-objects, and the ring-shaped printed circuit plate is made with possibility of its installation when carrying out the examination lower than anterior pole of the eye ball, and in that case it is provided with a collar for protecting eyes against irradiation, or higher than the anterior pole of the eye ball.

EFFECT: application of the invention makes it possible to increase quality and reliability of the information obtained during examination of patient's visual field.

18 dwg

Description

The invention relates to medicine, in particular to ophthalmology, and in particular to perimeters for subjectively detecting the presence of a test stimulus against a specific background, and can be used for early diagnosis of primary glaucoma and other diseases that limit the field of view of the human eye.

A device for studying the field of view is known (USSR author's certificate No. 1680056, MPK5 А61В 3/024, 1991), including a hemispherical screen with LEDs located on its surface, a fixation optical mark, as well as power, control and registration means. The known device is equipped with flanges for rotating a hemispherical screen, which, in turn, allows you to increase the number of test objects presented per unit area of the field of view and, accordingly, increase the accuracy of the study of the field of view of the patient.

The known device has the following disadvantages, narrowing its functionality. Firstly, it does not allow to study the extreme peripheral boundaries of the field of view, which is fundamentally important, for example, for the early diagnosis of glaucoma. The limited diagnostic capabilities of the device for studying the visual field are due to a largely ineffective constructive design of the hemispherical screen, the geometric shape of which differs significantly from the geometric shape of the retina of the eye, which does not allow to study and receive a response to light irritation of the most peripheral peripheral retinal photosensitive elements of the patient’s eye . Secondly, the device according to copyright certificate No. 1680056 is characterized by rather large dimensions of a hemispherical screen with light test objects, which significantly limits the area of its effective use. In particular, the device cannot be used to check the field of view of bedridden patients and in the field, as well as for self-monitoring at home for patients with glaucoma.

A known method for the early diagnosis of open-angle glaucoma (RF patent No. 2220644, A61B 3/024), which is implemented using stationary projection perimeters, in particular the perimeter of domestic production PRP-50. The combination of rather complicated manipulations with the patient’s head partially solves the problem of increasing the studied field of view of the patient.

The main disadvantages of implementing this diagnostic method are the large dimensions of the stationary projection perimeters and the low accuracy of positioning the patient’s eye with respect to the coordinates of the light test objects when turning the head relative to the perimeter.

As the closest analogue to the claimed technical solution for the achieved technical result, a device for studying the field of view (patent RU No. 2285440, MPK8 А61В 3/024, 2006) was selected, containing a demonstration screen with perforations and light point test objects in the form of LEDs for presentation to the patient, and the screen is made in the form of a hollow sphere and placed with a gap in the body of a spherical shape with a handle. The fixation light test object for fixing the patient’s gaze is located on the central axis of the screen, the observation window for observing light point test objects is located opposite the fixation light test object, while the diameters of the body, screen and viewing window are selected in accordance with the horizontal size of the human eye socket.

The disadvantages of the device according to patent RU No. 2285440 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 due to a combination of the following factors:

- the presence of only one fixation light test object located on the central axis of the demonstration screen, which does not allow optimizing the number of light test objects (stimuli) to ensure the maximum size of the examined field of view, or, in other words, increase the number of potential locations of the presented stimulus using the least amount of light test objects;

- the absence of a uniform background of adjustable brightness, on which the patient detects stimuli, since these stimuli are located in the perforations of the demonstration screen, directly facing the patient's eye, while the device does not have means for illuminating the demonstration screen.

The technical result, to which the claimed invention is directed, is to improve the quality and reliability of the information obtained in the study of the patient’s field of vision.

The technical result is achieved by the fact that in the inventive device, in comparison with the prototype, the number of potential locations of the presented stimulus (light point test object) is increased using the smallest number of light emitters and the examined field of view of the patient is expanded by introducing at least one additional fixation light test object, offset from the central axis of the demonstration screen, while light point test objects and fixation light test objects are located laid behind a translucent demo screen equipped with backlight.

The claimed technical solution is illustrated by drawings.

Figure 1 shows the layout of the device relative to the face of the patient;

figure 2, 3 illustrates the implementation of the demonstration screen, the perforated sector of the sphere and the location of the emitters of test objects;

figure 4 shows a view of figure 3;

figure 5 shows a view B of figure 4;

6 illustrates the connection of fiber optic waveguides to a light-emitting screen;

Fig.7 shows an example of the location on the demonstration screen of two fixation light test objects;

on Fig illustrates the organization of the illumination of the demonstration screen from the side of the patient's eye;

figure 9 shows a view in Fig;

figure 10 shows the location of the backlight LEDs on the printed circuit board;

figure 11 illustrates an example implementation of an adjustable nozzle;

on Fig, 13 shows a variant of the structural embodiment of the device;

on Fig shows a device with a display for indicating the results of the examination of the field of view, side view and front view;

on Fig shows a section GG of Fig;

on Fig shows an example of the location and number (76) of possible places for presentation of the stimulus with one (central) fixation object at 76 emitters of light test objects;

on Fig shows the possible locations of the stimuli and their number (380) using additional (four) fixation objects at 76 emitters of light test objects;

on Fig shows the possible locations of the stimuli and their number (760) using additional (four) fixation objects and using a screen rotation of 22.5 ° at 76 emitters of light test objects.

The inventive device for the study of the field of view contains a housing 1, in the cavity of which is installed a demonstration screen 2 for presenting the patient with light point test objects. The screen 2 faces the inner surface of the perforated sector 3 of the sphere, is axisymmetric with it, repeats its shape and fits snugly against it. The housing 1 is given the shape of a truncated cone with a solution angle, for example, 104 degrees. This body geometry is more optimal compared to the sphere and from the point of view of the structure of the face and is more technologically advanced, and the selected angle of the cone solution allows examination of the patient’s central (25 degrees) and mid-peripheral (50 degrees) field of view without any additional measures . The housing 1 is made of a material opaque to external radiation. The screen 2 is made of a material (for example, translucent plastic) that transmits, at least partially, the radiation generated by the light point test objects. The thickness of the screen 2 is selected from the condition of ensuring the necessary brightness and maximum clarity of the boundaries (sizes) of light point test objects. The screen 2 can also be made in the form of a layer of paint (for example, white matte paint) or a polymer material deposited by spraying on the inner surface of the perforated sector of the sphere 3.

Light point test objects can be LEDs 4 located in perforations of sector 3. Perforations in sector 3 and, respectively, point test objects are located along eight half-meridians with a step of 45 degrees. The minimum number of test objects on the semi-meridians corresponds to the generally accepted arrangement: after 10 °, starting at 10 ° on each even and starting at 5 ° on each odd. In this embodiment, the LEDs 4 are placed on a flexible printed circuit board 5 mounted on the perforated sector 3, or mounted directly in the perforations and electrically connected via wires to the control board 6. The light point test objects can also be output apertures of the optical fibers 7, fixed in the perforations of sector 3, while the input apertures of the optical fibers 7 are optically connected with the LEDs 8, and the output apertures of the optical fibers 7 abut against the demonstration screen 2, projecting imposed incentives on him. In this embodiment, the LEDs 8 are located on the control circuit board 9, which, in turn, is mounted on a plate 10 mechanically connected to the perforated sector 3. The radiation generated by the LEDs 8 propagates through the optical fibers 7 due to the effect of total internal reflection from the walls of the optical fibers. This solution has its advantages, since it significantly facilitates the replacement of radiation sources (in this case, LEDs) and allows, in particular, to quickly change the colors of point test objects.

Light point test objects can also be output apertures of optical fibers 7 optically coupled to a light-emitting screen 11, which is, for example, a computer display.

The LEDs that are the radiation sources for the presented stimuli are connected to the power supply, control, and registration unit 12. Block 12 is configured to individually control the brightness of each LED (and, accordingly, each stimulus), which eliminates the variation in the parameters of the radiation sources. The angular dimensions of the stimuli are selected according to ISO 12866 equal to 0.43 degrees.

The number of fixation light test objects in the inventive device is greater than in the prototype by at least one test object, and one fixation light test object is located on the central axis of symmetry of the device (axis of symmetry of screen 2 and sector 3), and the other , an additional test object is shifted relative to the central axis of symmetry of the device by a given angle (for example, by an angle lying in the range of 1-50 degrees.). Fixation light test objects can be made in the form of several (at least two) independent LEDs 13 and 14 installed in the perforated sector 3 and connected with block 12, or selected from among light point test objects for presentation to the patient. This possibility is realized due to the fact that the brightness of each LED can be individually adjusted.

Fixation points (fixation light test objects) are constantly luminous or blinking. The use of several fixation points can significantly increase the number of locations presenting the stimulus and to examine the peripheral field of view of the patient without the need for mechanical manipulations with the inventive device or moving the patient’s head. This is due to the rotation of the eyeball when fixing the gaze on a different from the central fixation object with a fixed head and device; in this case, the available locations of the stimulus are oriented to new corneal points displaced to the periphery. By optimizing the location and number of light test objects and fixation points, using the minimum number of emitters, it is possible to more densely cover with possible locations the most critical (most important) ones from the point of view of diagnosing the area of the studied field. For example, the central field and peripheral (nasal and temporal) zones.

In the housing 1 closer to the patient’s eye opposite the demonstration screen 2 is a backlight device. The purpose of this device is to provide illumination of the inner surface of the screen 2, while eliminating the likelihood of radiation entering the patient’s eye. The backlight device can be implemented in the form of LEDs 15, evenly mounted on the circuit board 16, which is given the shape of a ring. The printed circuit board 16 with LEDs 15 is made with the possibility of installing it below the front pole of the patient’s eyeball during the study and is equipped with a shoulder 17 to protect the eyes from LED radiation or is a larger ring with the possibility of installation above the front pole of the eyeball, providing a fairly wide angle review.

As sources of radiation in the backlight device, LEDs can be used that generate radiation in various regions of the spectrum (LEDs of different colors) and create, when alternately or jointly turned on, the background color of the demonstration screen necessary for studying the field of view.

Light sources with the same radiation spectrum can be used as light point test objects for presentation to the patient and means for illuminating the demonstration screen.

Fixation light test objects can be made in the form of point light sources that differ in color from the color of light point test objects and the color of the illumination means of the demonstration screen.

In the housing 1, a viewing window 18 is made for the patient to observe light point test objects, in which an adjustable nozzle 19 is located, configured to control the distance from the upper pole of the eyeball to the screen 2. The nozzle may be, for example, a hollow pipe moving along the thread made in the housing 1, or a set of hollow pipes of various lengths installed in the viewing window 18 of the housing 1 in a tight fit. The nozzle 19, as it were, “moves” the patient’s eye in relation to the screen 2, and its use allows the inventive device to be used by patients with various degrees of eye fit (for example, with deep-set or strongly bulging eyes).

The housing 1 is equipped with a handle 20 and an additional handle 21, the axes of which are located at an angle less than 180 degrees, for example at an angle (180 degrees - 180/8) = 157.5 degrees. - with the location of point test objects in eight half meridians.

The housing 1 can be made up of two parts 22 and 23, which are mechanically connected but rotate relative to each other. In this embodiment, the demonstration screen 2 and the perforated sector 3 of the sphere with light point test objects placed on it for presentation to the patient and fixation light test objects are installed on one part of the housing 23.

On the back of the case, behind the perforated sector 3, there is a display 24 (for example, liquid crystal or LED) for indicating the results of the field of view, mechanically connected to the housing 1. The display 24 is equipped with a coordinate grid deposited on its screen, for example, a grid of polar coordinates. A translucent blank 25 may be placed on the display screen 24 for copying the results of the field of view examination onto it. For reliable placement of the form 25, the display screen 24 is provided with a shoulder 26.

Using cable 27, the control board LEDs, which are sources of radiation of test objects and radiation backlight, are connected to the power supply, control and registration 12, made, for example, in the form of a personal computer. On the cable 27 is a button "saw" 28. The button position is selected so that both the patient and the doctor can work with the button. This facilitates, in particular, examination of the field of view of patients with limited motor skills.

The study of the visual field of the patient’s eyes using the inventive device is as follows.

The device is connected to the power supply, control and registration unit 12 (for example, a computer). Using the handle 20, the patient installs the device by means of the nozzle 19 (the height of which is adjusted to the depth of the patient’s eye fit) tightly to the examined eye. The second eye is closed. The patient fixes his gaze on one of the fixation points (switched on), and he is presented with light point test objects (stimuli) in the form of luminous points located on the spherical surface of the demonstration screen 2. The patient (or the doctor by the patient’s voice command) using button 28 registers their perception, and the condition of the patient's visual system is determined by fixed points.

In the process of studying the field of view, the doctor (or the computer according to the specified program) alternately turns on other fixation points and, if necessary, a more detailed examination, rotates screen 2 with light test objects around its central axis, thereby increasing the number of stimulus locations and expanding the examined field of view . The rotation can be carried out by one or several predetermined angles by rotating the screen with stimuli relative to the fixed viewing window or by one predetermined angle (for example, by 22.5 °) by flipping the entire device using the second, additional handle 21. After presenting all the stimuli, the information received it is processed, an analysis of the results of the study is performed, and an appropriate diagnostic conclusion is made about the condition of the patient’s visual system.

Claims (1)

A device for examining a visual field, comprising a body in the cavity of which a perforated sector of the sphere is installed, with light point test objects placed in perforations for presentation to a patient and a fixation light test object placed on the central axis of the perforated sector, while in the case provided a handle, a viewing window is made, and the light point test objects and the fixation light test object are connected to the power supply, control and registration unit, characterized in that it is equipped with about the demonstration screen facing the inner surface of the perforated sector of the sphere, axisymmetric with it and repeating its shape; at least one additional fixation light test object located in the perforated sector of the sphere, offset from the central axis of the demonstration screen and connected to the power supply, control and registration unit; demo screen illumination means located on the inside of the housing on an annular printed circuit board and facing the demo screen; wherein the demonstration screen is made of material that transmits at least partially the radiation of light point test objects and fixation light test objects, and the ring-shaped printed circuit board is configured to be installed below the front pole of the eyeball during the study, and then it is equipped collar to protect the eyes from radiation or above the anterior pole of the eyeball.

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