RU2214150C2 - Device for performing computer-aided diagnosis of single side optic nerve atrophy - Google Patents

Abstract

FIELD: medical engineering. SUBSTANCE: device has PC, controllable light source electrically connected to means for producing impulses, means for producing impulses and storage unit and buttons for controlling process for sending signals to the controllable light source. The device has trial glass rim with two non-transparent hemispheres fixed therein. The controllable light source has a set of bicolor and tricolor photodiodes mounted in the hemispheres at an angle to the main optical axis of the left and right eye, respectively. Two bicolor photodiodes are arranged in the central part of the left and right hemisphere, respectively. Display unit for indicating critical flicker fusion frequency of each of retina sight under test is connected to the PC. Means for producing impulses, means for shaping impulses and the storage unit are micro-controller units connected to the PC and photodiode inputs. EFFECT: high accuracy in determining optic nerve pathologic changes. 3 cl, 6 dwg

Description

 The invention relates to medical equipment, and more specifically to a device for computer diagnostics of unilateral atrophy of the optic nerve fibers during ophthalmic examinations.

 The invention allows to separately study the temporal and nasal, as well as the macular area of the retina and, accordingly, the optic nerves coming from the ganglion cells of these areas of the retina.

 In ophthalmic practice, several methods are used to diagnose the field of view associated with various levels of the visual system, starting with the retina and ending in the visual cortex.

 Some of them are based on the use of field of view analyzers, including automatic (perimetry, campimetry), which allow us to study the light and color sensitivity of the visual system during stimulation of local parts of the retina.

 In ophthalmology, the perimetry method is used to study the field of view. Currently, various perimeters based on computer technology are widely known.

 An automatic field analyzer has been developed that works on the principle of static perimetry. The analyzer contains a hemispherical screen on which luminous test objects are presented to the patient according to a given program. At the moment of recognition of the test object, the patient presses a button and the data is recorded in the computer memory. In the indicated analyzer, 28 test objects were used for four meridians, as the most informative in detecting glaucoma.

 Along with perimetry, the clinic widely uses the study of the function of the visual analyzer along the entire length of the visual path from the retina to the central departments, recording the critical frequency of flicker fusions (CFSM). By CFSM is meant the maximum frequency of intermittent light radiation at which the eye begins to perceive radiation as continuous. At a low flicker frequency, the patient sees a series of flashes, and with an increase in the flicker frequency, a flickering sensation appears and, finally, a feeling of a complete flicker fusion.

 In ophthalmic practice, CFSM serves as a criterion for the diagnosis of a number of diseases, as well as for professional selection and preventive examinations of workers whose activities are associated with prolonged eye strain.

 A known apparatus for studying the field of view (see, for example, US patent 930615), in which to study the field of view of the retina, the light image is projected at an angle to the optical axis of the eye. The apparatus contains a hemispherical screen, a device for fixing the gaze, a video monitor for controlling the gaze and a special device for projecting images of various intensities with a given variable displacement on the screen.

 The disadvantage of this device is the duration of the study, the inability to determine the critical fusion flicker frequency at a given point in the visual system. The device does not provide the ability to change the color of the stimulus. The device has a complex design and is expensive.

 A known method for diagnosing pathology of the optic nerve (see, for example, RF patent 1,734,682), which consists in determining the threshold of electrical sensitivity of the retina at two opposite points of the eyeball and diagnosing the pathology of the optic nerve at a level of more than 15 μA the retina.

 The disadvantage of this method is the fact that when stimulated by the optic nerve current at one or more points of the eyeball, part of the stimulating current excites ganglion cells in the temporal part of the retina during stimulation of the nasal part of the retina and, conversely, part of the stimulating current excites ganglion cells in the nasal part during stimulation temporal part of the retina.

 Other known methods for diagnosing pathology of the optic nerve use devices to determine the critical frequency of flicker fusion.

 However, all known devices do not allow to fully diagnose a number of eye diseases. So, for example, the study of CFSM in the form as it is used in the clinic does not allow fixing the deviation of CFSM from the norm in individual local parts of the field of view. Numerous studies have shown that the value of CFSM is heterogeneous in the center of the eye and on the periphery. For a healthy person’s macular zone, CFSM is 40-41 Hz per red stimulus and 43-45 Hz per green stimulus, and for the periphery of the temporal part of the retina CSCM is 55-60 Hz. For the nasal part of the retina, CFSM is normally 50 Hz or more. With a high degree of myopia with characteristic changes in the fundus, CBSM decreases in the peripheral zones of the field of view, especially in the temporal zone, while in the macular zone CSCM readings correspond to the norm (see, for example, Golubtsov K.V., Zueva M.V., Tsapenko IV, Yakovlev AA "Study of the functional state of the visual system by the CESM method", Modern aspects of neuroophthalmology, Burdenko Research Institute, Moscow, 1997).

 With the usual method of studying CFSM in the initial stage of glaucoma (see, for example, Description of a utility model of the Russian Federation 5097, 1997), the patient sees flickering at a frequency of 41 Hz and the doctor fixes that CFCS is normal. In fact, CFSM in glaucoma often decreases precisely in the nasal part of the retina from 55 Hz normal to 40 Hz and below. It is difficult or impossible to identify the initial stage of glaucoma or unilateral atrophy of the optic nerve in the indicated way of studying CSFM.

 It is known that, normally, with a central presentation of the light stimulus, the CSFM is 5–10 Hz lower than when the peripheral zones of the retina are exposed, and is not equivalent for the nasal and temporal regions. For the macular zone for the healthy eye, the CFFF is on average 45 Hz, and for the periphery of the nasal region 55-60 Hz.

 It is also known that in case of adenoma, CFSM decreases on the periphery of the retina while maintaining normal values in the macular region of the retina (Miles P. "Flikerfision fields, technique and interpretation", Am. J. Ophth, 33, p. 1069-1077, 1950 or Miles R. "Testing visual fields by fliker fision" Arch. Neurol. & Psychiat. 65, pp. 39-47, 1951).

 It is known that atrophy of the optic nerve is not always the result of an eye disease or an isolated disease of the optic nerve, but is often associated with basal tumors of the anterior and middle cranial fossa, especially with lesions of the pituitary chiasmal-selar region, pituitary adenoma, minigioma of the tubercle of the Turkish saddle, optic hyoma nerve and chiasm (see, for example, Zhinzhina N.V. “On unilateral simple atrophy of the optic nerve.” Optometrist, 8-10, 12-14). Early diagnosis of such diseases has still been difficult.

 A portable device for the study of CFSM is known, which contains an autonomous power source, to which a pulse generator is connected, connected to a frequency driver, to the output of which a controlled light source is located, located in the housing, which also contains a light panel and a registration button (see, for example, Federal Republic of Germany patent application 3,831,947, 1991.) This device does not provide reliability of the research results for various pathologies of the optic nerve, there is also no possibility of separate diagnostics of fibers ritual nerve.

 Currently, computer-aided methods of studying the brain are widely used, however, the detection of tumors in the area of chiasm in the initial stage of the disease remains a big problem.

 At the same time, when studying the CSFM of the macular zone, it was noted that with increasing stimulus brightness, the flicker fusion frequency increases. Such an increase in CFSM is due to the fact that as the stimulus increases in brightness, the area of retinal illumination increases as a result of light scattering in the vitreous body of the eye, hence CFSM readings are recorded from the paramacular zone of the retina, where CFSM is several Hz higher, especially for the green stimulus.

 A device for studying the critical frequency of flicker fusion is known (see, for example, RF patent 38162, 1993), which also does not allow separate investigation of the nasal and temporal zones of the retina, as well as the macular zone.

 The closest technical solution is a device for computer diagnostics of the optic nerve, containing a controlled light source, electrically connected with a means for generating and means for generating pulses and a storage device, and buttons for controlling the supply of signals to a controlled light source (see, for example, Description of utility model 5079 RF, 1995).

 The disadvantage of this device is the lack of the possibility of a separate study of CSFM in the nasal and temporal zones of the retina and individual zones of the visual pathway.

 The basis of the present invention is the creation of a device for computer diagnostics of unilateral atrophy of the optic nerve fibers, which will allow for separate diagnostics of the pathology of the fibers of the temporal, nasal and macular parts of the optic nerve, especially with unilateral simple atrophy of the optic nerve, which is often found in basal tumors of the anterior and middle cranial fossa and especially often with damage to the pituitary chiasmal-sellar region, i.e. pituitary adenoma, Turkish saddle tubercle meningioma and optic nerve glioma or other pathological processes in the field of chiasm.

 The present invention allows with great accuracy to determine the pathology of the optic fibers originating from both the nasal and temporal parts of the retina by examining the critical fusion flicker frequency. But in contrast to the widespread method of registering CFSM, when the entire retina is illuminated, in the claimed device, retinal stimulation is carried out exactly in a given local area of the retina, for example, temporal or nasal. It is also possible to stimulate only the macular region.

The problem is solved in that the device for computer diagnostics of one-sided atrophy of the optic nerve fibers, containing a controlled light source, electrically connected with a means for generating and means for generating pulses and a storage device, and buttons for controlling the supply of signals to a controlled light source, according to the invention contains
test eyeglass frame, in which two opaque hemispheres are fixed,
as a controlled light source used a lot of two-color / three-color LEDs placed in these hemispheres at an angle to the main optical axis of the eye at least three circles evenly,
a display to indicate the critical flicker fusion frequency (CFSM) for each retinal site to be tested,
wherein the means for generating pulses, the means for generating pulses and the storage device are elements of a microcontroller that is connected to a personal computer and to the LED inputs,
and the buttons for controlling the signal are elements of the keyboard of a personal computer.

 It is advisable that the device contains at least two additional two-color LEDs, each of which is placed in the Central part of the right and left hemispheres, respectively, and is electrically connected to the microcontroller.

 It is useful that the axes of maximum radiation of the LEDs installed in the hemispheres are placed at an angle α to the main optical axis aa and bc of the left and right eyes, respectively, and this angle is in the range of 10 to 80 degrees. angular.

 Advantageously, the hemispheres are fixed in a trial spectacle frame with the possibility of turning clockwise or counterclockwise.

The invention is further explained in the description of the preferred options for its implementation with reference to the accompanying drawings, in which:
FIG. 1 shows a general view of a device for computer diagnostics of unilateral atrophy of optic nerve fibers according to the invention;
FIG. 2 depicts a block diagram of a computer diagnostic device according to the invention;
FIG. 3 depicts a hemisphere arrangement of controllable light sources according to the invention;
FIG. 4 shows sections of hemispheres with controlled light sources that correspond to the affected areas of the retina according to the invention;
FIG. 5 is a CESM map of a patient with a brain tumor according to the invention;
FIG. 6 is a flowchart for diagnosing an optic nerve pathology according to the invention.

 A device for computer diagnostics of unilateral atrophy of the fibers of the optic nerve (Fig. 1) contains a controlled light source 1 (Fig. 2), electrically connected to a means 2 for generating, with a means 3 for generating pulses and a storage device 4.

 The device also contains a test spectacle frame 5 (Fig. 1, 2), in which two opaque hemispheres 6, 7 are fixed (Fig. 2).

 As a controlled light source 1, a plurality of two-color / three-color LEDs 8 are used, which are placed in the indicated hemispheres 6, 7 at an angle α to the main optical axis aa, b-in the eye 9, 10 in at least three circles 11, 12, 13 (figure 3) evenly. The number of LEDs ranges from 17 to 38.

 In the claimed device, the means 2 for generating pulses and the means 3 for generating pulses, as well as the storage device 4 are elements of a microcontroller 14 (Fig. 1) controlled by a personal computer 15. The output 16 of the microcontroller 14 is connected to the inputs of the LEDs 8.

 A display 17 for indicating the critical flicker fusion frequency (CFSM) for each tested portion of the retina is connected to output 18 of a personal computer 15.

 To control the signaling, buttons 19 are used, which are elements of the keyboard 20, which is connected to a personal computer 15.

 The device contains at least two additional two-color LEDs 21, 22, each of which is placed in the Central part of the right and left hemispheres 6, 7, respectively, which are electrically connected to the microcontroller 14.

 The directivity of the maximum radiation of the LEDs 8 installed in the lens hoods 6, 7 is at an angle α to the main optical axis aa and bc of the left and right eyes, respectively, and this angle is in the range from 10 to 80 degrees. angular.

 Hemispheres 6, 7 (Fig. 3) are fixed in a test spectacle frame 5 with the possibility of rotation clockwise or counterclockwise.

 A device for computer diagnostics of unilateral atrophy of the optic nerve fibers works as follows.

 During the study, the patient is instructed to constantly fix his gaze with one eye on the central luminous LED 21 (Fig. 3), for example, in the left hemisphere 6. And on the LEDs 8 of the right hemisphere 7, a flickering red light signal is transmitted sequentially along several circles 13, 12, 11, green or blue with increasing flicker frequency, starting from 5-10 Hz according to the program of computer 15 for the diagnosis of various zones of the field of view.

 The moment is determined when the flickering light with increasing flicker frequency will be perceived by the patient as a constant light signal, i.e. determine the critical fusion flicker frequency (CFSM).

 Depending on the requirements of the study, the CFSM can be determined in the opposite direction, i.e. in the direction of decreasing the frequency of flicker fusion, until the patient begins to perceive flicker.

 In this case, the digital readings of the flicker fusion for each stimulation point along the radius and circles 11, 12, 13 (Fig. 4) are recorded, displayed on a printer (not shown) and stored in the computer memory. Examine all 39 points. Then proceed to the examination of the other eye in the same way.

 Based on the survey results, they compose a topological map. The indicators of the flicker fusion frequency or the flicker occurrence are fixed according to the patient’s answers or the patient himself presses the button at the moment the light signal frequency changes.

 Light sources 21, 22 operate in two modes - in the fixation mode for one eye and in the CSFM research mode at several gradations of brightness.

 First, the central macular zone is checked for a red stimulus, since mainly red cones with a wavelength of 630 nm are concentrated in the macula. The CSFM is determined, and then eight points are examined along the first circle 13 from the center of the circle for red and green. Then go to the second circle 12 and the third circle 11.

 Adaptation mode is provided. To adapt, first a red, non-flickering light with a wavelength of 630 nm is simultaneously applied to the entire field of view, i.e. all 8 LEDs, for two to three minutes, and then green or blue light is supplied. Thus, white light illumination is carried out. After that, colored stimuli with a change in the frequency of flickers are presented against a background of white light.

 The device was tested on 50 patients, 40 of whom were diagnosed with normal vision without pathologies, and 10 patients were diagnosed with partial atrophy of the optic nerve.

 Example 1

 Patient K, 74 years old. OD - healthy, no changes in the fundus. OS - diagnose partial retinal detachment in the temporal part of the eye. Complaint: something is interfering in the upper half of the eye. As can be seen in figure 4 at two points A1 and A2, marked with a cross, the patient recorded a complete absence of CSFM. This indicates that the patient has either a retinal pathology or partial atrophy of the optic nerve. For this case, additional diagnostics are required, i.e. removal of local electroretinograms.

 Example 2

 Patient N, 50 years old. OD - healthy, no changes in the fundus. OS - diagnose a decrease in CFSM in the nasal part of the retina. As can be seen in figure 4 at four points B1, B2, B3 and B4, marked with a cross, the patient recorded a decrease in CSFM by 20-30 Hz. This indicates that the patient has either a retinal pathology or partial atrophy of the optic nerve. For this case, additional diagnostics are required, i.e. removal of local electroretinograms.

 Example 3

 Patient M., 65 years old. OS - healthy, no changes in the fundus. OD - the fundus is normal, CSFM in the macular part of the retina for a given age is normal and is 40 Hz. In the central part - point C1 - 30 Hz is fixed. The diagnosis of glaucoma of the second degree.

 Example 4

 Patient S., 37 years old. The diagnosis is a brain tumor with dominant changes in the occipital lobe of the left hemisphere, there are no changes in the fundus. Additional electroretinographic studies did not reveal pronounced changes in retinal electrogenesis. A survey on the proposed device confirmed the diagnosis. A generalized decrease in the flicker sensitivity of the retina by 10–20 Hz, which is most pronounced for the left halves of the stimulated field of view, was revealed on the CFSM map (Fig. 5) of the patient. Inside the circles, the value of CFSM is indicated.

 Figure 6 presents the algorithm according to which computer diagnostics of the field of view is carried out. Choose a color: green, blue, red. Set the initial flicker frequency. Select the right or left eye for diagnosis. Set the color of the fixation point. Choose a circle. Choose a radius. Begin research. If flicker is noticeable, increase the frequency, if not noticeable, fix the value of the CFSM, switch to another radius on the same circle. Check all the points on the circle, check the points on the second circle and on the third circle. Check CFSC for all colors. Switch to another eye and repeat all the steps.

Claims (3)

 1. A device for computer diagnostics of unilateral atrophy of the fibers of the optic nerve, containing a personal computer, a controlled light source, electrically connected with a means for generating pulses, a means for generating pulses and a storage device, and buttons for controlling the supply of signals to a controlled light source, characterized in which contains a test eyeglass frame in which two opaque hemispheres are fixed, the controlled light source contains many two-color or three-color LEDs placed in hemispheres at an angle to the main optical axis of the left and right eyes, respectively, at least three circles evenly, and at least two two-color LEDs, each of which is placed in the Central part of the right and left hemispheres, respectively, a display for indication the critical fusion flicker frequency for each tested portion of the retina connected to a personal computer, the means for generating pulses, the means for generating pulses and a storage device are Tammy microcontroller, which is connected to a personal computer and inputs LEDs and buttons for feeding control signals are the elements of the keyboard of a personal computer. 2. The device according to p. 1, characterized in that the angle between the axes of the maximum radiation placed at an angle of the LEDs and the optical axis of the left and right eyes, respectively, is in the range from 10 to 80 ^o .  3. The device according to claim 1, characterized in that the hemispheres are fixed in a trial spectacle frame with the possibility of rotation clockwise or counterclockwise.

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