RU2409306C1 - Device to investigate field of view - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: device comprises body with handle, equipped with button, and sight window to observe light test-objects. Demonstration screen is installed in body cavity with holes and light point test-objects placed into them. Body is arranged as cylindrical. At the same time one of end surfaces at the side of sight window is arranged as spherical with protrusion, and handle of body is arranged with the possibility of rotation around its central axis. Demonstration screen is arranged as light-radiating with hole in central part. Test-objects are fibre optic elements, installed and fixed in holes of demonstration screen and connected to light diodes to illuminate fibre optic elements arranged in control unit, connected to USB port of personal computer via unit of galvanic isolation. Element of view fixation and its position monitoring is installed and fixed on central axis of demonstration screen in control unit.

EFFECT: application of this device makes it possible to increase accuracy of investigation results, to constantly monitor position of patient's pupil, and also provides for a permanent and accurate size of test-object, which makes it possible to carry out early diagnostics of glaucoma.

12 cl, 3 dwg

Description

The invention relates to medicine, in particular to ophthalmology, and can be used for early diagnosis of primary glaucoma and other diseases that limit the field of view of the human eye.

The prior art device for the study of the field of view (USSR Author's Certificate No. 1680056, published September 30, 1991, IPC: А61В 3/024), which contains a hemispherical screen with LEDs located on its inner surface, a program block for switching on the LEDs, and a registration unit answers, control panel. This device is characterized by increased accuracy of the study by increasing the accuracy of the number of test objects presented per unit of field of view. Moreover, the device allows to increase the accuracy of exposure of the studied eye to a predetermined position. The advantage of the device is the fixing of a hemispherical screen on the flange with the possibility of rotation in the range 0-90 °.

The disadvantages of this device include the rather large overall dimensions of a rotary 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 (Patent RU No. 2220644, published January 10, 2004, IPC: AB61 3/024), which is implemented using a projection perimeter of domestic production PRP-50. Using the PRP-50 perimeter and a combination of rather complicated manipulations with the patient’s head partially solves the problem of increasing the patient’s field of view. Due to the displacement of the gaze fixation point and the head rotation of the examined patient on the surface of the perimeter sphere, some correction of the boundaries narrowed by the influence of the prominent parts of the eye socket and nose is achieved.

Given the shape of the inner shell of the eye - the retina, which is a little more than a hemisphere, it would be more correct to get a visual field in the form of a circle. On the instruments available in practice, such as a portable arc perimeter (Ophthalmic Instruments, p. 45), the PNR-1 perimeter (ibid., Pp. 45-46), the projection perimeter PRP-60 (ibid., P. 46 -51), a hemispherical projection perimeter manufactured by K. Zeiss Yen (pp. 51-52), etc., the field of view looks like an ellipse. The most vulnerable, in terms of the development of optical neuropathy, peripheral parts of the retina, diagnosed by narrowing the boundaries of the field of view, are first detected only by narrowing them by more than 45-50 ° in one or more of the three (upper, inner and lower) quadrants of the field of view. In addition, the study of peripheral vision on the indicated equipment is stationary methods requiring a special room, large-sized, expensive equipment, not suitable for examining bedridden patients and conducting dynamic monitoring in ophthalmologic rooms of regional polyclinics, and even more so at home.

Closest to the claimed is a device for the study of the field of view (Patent RU No. 2285440, published October 20, 2006, IPC: А61В 3/024), which is chosen as a prototype. The device contains a demonstration screen with perforations and light point test objects in the form of LEDs for presentation to the patient. A fixation light test object is fixed on the screen surface along its central axis. The device is equipped with a sphere-shaped body with a handle and a multi-bit bus for connecting LEDs to the LED control unit and the power supply source. In the cavity of the housing with a gap mounted demonstration screen, made in the form of a hollow sphere. Opposite the fixation light test object, a viewing window for observing light test objects is made in the housing and the demonstration screen. The case, the demonstration screen and the viewing window are respectively made with a diameter of (2.25-2.4) L, (1.75-1.9) L and (0.85-1.1) L, where L is the horizontal size of the human eye socket . This device is characterized by the possibility of early diagnosis of glaucoma due to the extended boundaries of the studied field of view - 90 ° from all sides.

The disadvantages of this device include the lack of illumination of the demonstration screen, which does not allow to determine the differential photosensitivity of the retina in each studied area; lack of control over the fixation point of the patient’s gaze, which can lead to inaccuracy of the results. As well as small holes in the demonstration screen, with a diameter of (0.5-1) mm, can cause light diffraction, which will lead to an increase in the size of the test object and, consequently, to a decrease in the accuracy of studies, due to the reduction of clearly observed test objects, especially where they are most densely located (center of the demonstration screen).

Some models of modern devices for studying the field of view allow using the static (fixed position of light objects) or kinetic (moving in the field of view) perimetry method to determine peripheral borders within certain limits, depending on the anatomical natural formations of the facial skull. Therefore, the upper, inner and lower boundaries are limited to approximately 60 °, and the outer has a maximum value of 90 °. However, it is the inner borders that begin to narrow when optical neuropathy develops, which is recorded as the appearance of the “nasal step”. This means that the pathognomonic for the glaucoma process will be the loss of lower- or upper-inner quadrants of the visual field. The diagnosis of these changes is delayed, since it is impossible to see a light object due to a mechanical obstruction in the form of a nose, eyebrow and zygomatic bone. Determining the stage of glaucoma by the degree of narrowing of the visual field often does not correspond to a more significant change in the optic nerve head. Often the stage of the disease is specified in the direction of the progression of the glaucoma process precisely by the state of the optic nerve, which is more consistent with the level of disturbance of trophic retina and its pathways.

The technical result of the claimed invention is to improve the accuracy of the research results, to continuously monitor the position of the pupil of the patient, as well as to ensure a constant and accurate size of the test object, which makes it possible to carry out early diagnosis of glaucoma, as well as to increase the information content and quality of diagnosis of diseases of the retina.

The technical result is achieved due to the fact that the device for the study of the field of view contains a housing with a handle and a viewing window for observing light test objects. A demonstration screen with holes and light point test objects placed in them is installed in the body cavity. It differs from the prototype in that the body is cylindrical, and one of the end surfaces from the side of the viewing window is made spherical with a protrusion. The handle of the housing is rotatable around its central axis. The demonstration screen is made light emitting with a hole in the Central part. As test objects, fiber-optic elements are used that are installed and fixed in the openings of the demonstration screen and connected to LEDs to illuminate the fiber-optic elements located in the control unit connected to the USB port of a personal computer through a galvanic isolation unit. On the central axis of the demonstration screen in the control unit, an element is fixed and fixed to fix the gaze and control its position.

The proposed device for the study of the field of view has minimum dimensions with a light stimulus size of 0.5 mm, allows constant monitoring of the position of the patient’s pupil, due to the presence of a video camera, to determine the differential photosensitivity of the retina due to the constant illumination of the demonstration screen, and also provides a constant and accurate size test object through the use of fiber optic elements, which allows to increase the accuracy of measurements in the study of the field of view.

The invention is illustrated by the following drawings:

Figure 1 - General view of the device for the study of the field of view;

Figure 2. - sectional perimeter;

Figure 3 - appearance of the interface of the program for the study of the field of view.

Figure 1 shows a device for studying the field of view, including a spherometer 1, a galvanic isolation unit 2, which serves to provide galvanic isolation of the interface of the computer, and the interface 3 of the computer interface, which serves to connect the device to the USB port of a computer or laptop, provides necessary data exchange speed and device power.

The spherometer 1 (FIG. 2) contains a cylindrical body 4, consisting of two interconnected parts: the cover 5 and the base 6. On the outer cylindrical surface of the cover 5 of the housing 4 there is a ring 7 on which the handle 8 is mounted rotatably mounted on button 9 to answer the patient when he sees a luminous test object. The wires from the galvanic isolation unit 2 pass inside the handle 8 and enter the cavity of the housing 4. The cover 5 and the base 6 of the housing 4 are made of opaque material (for example, ABS plastic).

A part of the outer surface of the base 6 of the housing 4 adjacent to the eye is made in the form of a sphere passing into the main cylindrical body, the main cylindrical body being inclined (about 10 °) relative to its spherical part. This design of the housing 4 allows you to more tightly press the sphere perimeter 1 to the studied eye and to expand the field of view from the side of the nasal part.

The protrusion 10 on the outer surface of the base 6 of the housing 4 performs two functions: the first function is the expansion of the visual field in the temporal region to 90 °, the second is the guide, which allows to provide an unambiguous position of the spheroperimeter 1 relative to the patient's face, which leads to a large repeatability of the examination results and allows you to compare results of different time examinations of one patient.

To work with the other eye, the handle 8, mounted on the movable ring 7, is rotated 180 ° until it is fixed, the spheroperimeter is rotated so that the handle 8 is lower again, and the protrusion 10 lies on the temporal part of the head from the opposite side, after which the second eye is examined .

In the central part of the end surface of the base 6 there is a viewing window 11 for observing light test objects.

In the inner cavity of the base 6 of the housing 4, on one axis with the viewing window 11, there is a demonstration screen 12 with an inner diameter of 130 mm, made in the form of a hollow hemisphere with a central hole 13 and holes 14 of a smaller size for installing fiber optic elements 15. The demonstration screen 12 is fixed by arc brackets 16 on the inner end surface of the base 6.

The demonstration screen 12 is made of a light guide material (for example, plexiglass) processed according to light guide technology to give it light guide properties due to total internal reflection and partial light transmission. In this case, the screen thickness may be (3-7) mm. To illuminate the background of the demonstration screen 12, a board 17 (in the form of a flat ring) with LEDs 18 mounted on it is installed and fixed on it, electrically connected to the control unit 19, which makes it possible to use the demonstration screen 12 as a light guide.

Demonstration screen 12 may be performed on OLED technology.

On the entire surface of the demonstration screen 12, holes 14 are made with a diameter of (0.5-0.6) mm, which are necessary for installing fiber optic elements 15. In total, 128 holes are made in the light-emitting demonstration screen 12, which are arranged in a certain way and form 16 half meridians . On each even half-meridian, light test objects are located at 10 °, starting at 10 °, and on each odd half-meridian, light test objects are located at 10 °, starting at 5 °.

In the inner cavity of the cover 5 of the housing 1, a control unit 19 is installed for the LEDs 18 of the backlight of the demo screen 12 and the LEDs 20 for the backlight of the fiber optic elements 15, mounted on an annular bracket 21. The control unit 19 contains a control board 22 with control elements mounted on it, a fiber holder optical elements 23 and a digital video camera 24.

The connection of the demonstration screen 12 and the LEDs 20 for illumination of the fiber optic elements 15 is carried out using fiber optic elements 15, one end of which is fixed in the mandrel socket of the LED 20, and the other in the holes 14 of the demonstration screen 12.

For a given size of the demonstration screen 12, the diameter of the test object should be 0.5 mm. This size of the test object cannot be provided by any LED, therefore, to exclude light diffraction at small holes, fiber optic elements 15 with a diameter of 0.5 mm were used, which coincides with the calculated values.

The control board 22 is connected through a galvanic isolation unit 2 to the USB port of a personal computer or laptop on which a program is installed to register the results of the examination and send commands to the control board 22, maintain a database for each patient, configure the examination mode, as well as conduct the examination itself, both in automatic mode (without the participation of a doctor), and in semi-automatic mode.

The camcorder 24 performs two functions - the control element and the element of fixing the gaze. The image of the position of the pupil is fed to the monitor, which allows the doctor to constantly monitor the patient’s gaze, the program also recognizes the position of the pupil at the moment of pressing button 9 on the handle 8, and if at that moment the pupil deviates from the center, the program gives an error and informs the doctor about it, after which after a while, it repeats the test object (on which the error occurred). Camcorder 24 has a simple interface and sufficient resolution (640 × 480). When the patient presses the button 9 on the handle 8, the image from the video camera 24 is transmitted to the computer and displayed in the control program window. During the examination, the doctor in real time will be able to observe the position of the patient’s gaze.

The invention provides for color perimetry; for this, instead of colorless LEDs for illuminating the demonstration screen and LEDs for illuminating fiber-optic elements, it is enough to install multicolor or full-color LEDs.

The work of the proposed device for the study of the field of view is as follows.

The examination takes place in a fully automatic mode in two ways: static (all stimuli pseudo-randomly light up) and kinematic (last stimuli light up on each meridian in turn). With each method, there is constant double monitoring of the position of the eye - either visually by a doctor on a computer monitor in the program interface, or by the program yourself. Upon receipt of the “see” answer, an instant picture of the eye is taken, and the program recognizes the position of the pupil and its deviation from the central axis. If necessary, the recognition function can be turned off.

With the static method, the doctor sets the threshold minimum brightness of the test object, from which the examination begins. If the response “see” does not come from the patient on some test object, then the brightness of the test object rises one value up and the test object repeats again, after the maximum brightness, the non-observation zone of the test object is noted and the study continues further until All test objects will be checked.

With the kinematic method, the last test objects on each meridian light up; if the answer “I don’t see” is received, the next nearest test object on the same meridian lights up.

To conduct a survey, a device for studying the field of view must be connected to a computer or laptop with the necessary software installed, the appearance of the main interface of which is shown in Fig. 3.

To start the examination, the doctor fills in the fields 25, 26, 27, 28, selects the examination method (static or kinematic) using the drop-down menu 29, selects the examined eye with the switch 31, sets the initial brightness of the test object, with the switch 32 or the slider 33 adjusts more precisely, the slider 34 adjusts the brightness of the backlight (glow) of the demonstration screen. An image from a digital camera 24 is displayed in window 30. Slider 35 adjusts the required duration (activity time) of the test object, slider 36 adjusts the frequency of appearance of the test object (time between the two closest test objects). After all the fields are filled and the examination parameters are configured, the doctor presses the button “start examination” 37, the field 38 displays the current test object and the results of the patient’s responses (pressing the button 9 on the handle 8 of Figure 2). After the examination, the doctor presses the button 39 to save the examination results. In field 40, the doctor may choose to conduct not a complete examination, but, for example, only one sector.

The procedure for conducting static perimetry is as follows.

The doctor sets up the examination parameters - the interface of the program for conducting the examination (Figure 3), selects the examination area in the window 38 (either the entire field of view, or a specific sector) and presses the button 37 "Start examination". Light test objects begin to appear in a pseudo-randomly selected area with the frequency and duration set by sliders 35, 36. The patient fixes his gaze on the digital video camera 24 (Figure 2) and, if the test objects are visible, presses button 9. The program makes instantaneous a snapshot of the eye, recognizes the position of the pupil, when it is correctly positioned, captures the patient’s response. If the answer is not received or the pupil is in the wrong position, the answer is not recorded (the doctor makes a note to the patient). Missed test objects (for which no answer has been received) and test objects with the wrong position of the pupil are repeated again after a while. If the answer is not received again, the program automatically raises the brightness of the test object to the next step and repeats it. And this continues until all test objects are passed and, if necessary, all possible brightnesses of test objects are selected. After the examination, the field of view of the patient will be visible in window 38 indicating the sensitivity of the retina in each test object, and the doctor will draw a conclusion about the condition of the eye. The doctor also has the opportunity (if the patient has already been examined on this device) in window 38 to overlay the results of different examinations and compare the results in dynamics.

The procedure for kinetic perimetry is as follows.

The doctor sets up the examination parameters - the interface of the program for conducting the examination (Figure 3), selects the examination area in the window 38 (either the entire field of view, or a specific sector) and presses the button 37 "Start examination". Light test objects begin to appear pseudo-randomly, the last test objects of each half-meridian appear in the selected area with the frequency and duration set by sliders 35, 36. The patient fixes his gaze on the digital video camera 24 (Figure 2), and if he observes the test object, then presses button 9, the program takes an instant snapshot of the eye at this moment, recognizes the position of the pupil, when it is in the correct position, captures the patient's response. If the answer is not received or the pupil is in the wrong position, the answer is not recorded, the doctor makes a remark to the patient. Missed test objects (for which no answer has been received) and test objects with the wrong position of the pupil are repeated again after a while. If the answer is not received again, the program ignites the next (closer to the center) test object on the same half-meridian, and so it repeats several times until an answer is received. The examination continues until all half-meridians have been passed and an answer has been received to all extreme visible test objects. This examination takes place at a constant brightness. After the examination, the boundaries of the patient’s field of vision will be visible in window 38, and the doctor will draw a conclusion about the condition of the eye. The doctor also has the opportunity (if the patient has already been examined on this device) in window 38 to overlay the results of different examinations and compare the results in dynamics.

When working with this device for studying the field of view, it is possible to individually include in the program the work with each test object if it is required to set a threshold minimum sensitivity of the retina, smoothly changing the brightness of the test object, and also to establish certain examination areas (upper, lower, right, left quarter).

The program automatically saves the results of the examination and allows you to search among the results using the patient's last name, first name and patronymic as a filter, and it also allows you to print the current and saved examination results, as well as superimpose the results of current and past studies, which provides ease of comparison and allows see progress in dynamics.

In serial production, all parts of the spherometer are made by casting, which ensures a minimum cost and high adaptability of the device for studying the field of view.

Claims (12)

1. A device for studying the field of view, comprising a housing with a handle equipped with a button and a viewing window for observing light test objects, a demonstration screen with holes and light point test objects placed therein is installed in the cavity of the case, characterized in that the case is made cylindrical, and one of the end surfaces from the side of the viewing window is made spherical with a protrusion, and the handle of the housing is made to rotate around its central axis, while the demonstration screen is made light-emitting with a hole in the central part, and fiber optic elements installed and fixed in the holes of the demonstration screen and connected to LEDs for illuminating fiber-optic elements located in the control unit connected to the USB port of a personal computer are used as test objects through the galvanic isolation unit, on the central axis of the demonstration screen in the control unit, an element is fixed and fixed to fix the gaze and control its position. 2. The device according to claim 1, characterized in that the housing consists of two interconnected parts: base and cover. 3. The device according to claim 1, characterized in that the part of the outer end surface of the body adjacent to the eye is made spherical, passing into the main cylindrical body. 4. The device according to claim 1, characterized in that the possibility of rotation of the handle around the central axis of the housing is provided by means of a ring mounted on the housing. 5. The device according to claim 1, characterized in that the demonstration screen is hemispherical. 6. The device according to claim 1, characterized in that on the inner surface of the demonstration screen, LEDs are installed to illuminate it. 7. The device according to claim 1, characterized in that the demonstration screen is mounted on the inner end surface of the housing by means of arc brackets. 8. The device according to claim 1, characterized in that the control unit is made in the form of a control board with controls installed on it, a holder of fiber optic elements and an element for fixing the gaze and controlling its position 9. The device according to claim 1, characterized in that the element of fixing the gaze and controlling its position is made in the form of a digital video camera. 10. The device according to claim 1, characterized in that for the illumination of fiber optic elements use colorless LEDs. 11. The device according to claim 1, characterized in that colored LEDs are used to illuminate the fiber optic elements. 12. The device according to claim 1, characterized in that the demonstration screen is made according to OLED technology.

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