SU1514342A1 - Apparatus for investigating visual system - Google Patents

Description

The invention relates to medical equipment, namely, devices for research of the visual system. The device contains push-button switches 1 and 2 of a doctor and a patient, a control unit 3, a generator of 4 pulses, elements 5 and 6, a source code setting unit 7, reversible counters 8 and 9, two full video signal conditioners 10 and 11, a recording unit 12, a monitor 13. keys 14 and 15. TV receiver 16, 17 image generator and inverter

18. The purpose of the invention is to improve the accuracy of determining the contrast sensitivity of the eye. 1 il.

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The invention relates to medical technology and can be used for diagnostic purposes for the early detection of glaucoma and other lesions of the retina and optic nerve, assessing the dynamics of these diseases.

The aim of the invention is to improve the accuracy of determining the contrast sensitivity of the eye.

The drawing shows a block diagram of the device for the study of the visual system.

The device for studying the visual system contains a button switch 1 of the doctor, a button switch 2 of the patient, a control unit 3, a generator of 4 pulses, two elements I 5 and 6, a source code setting unit 7, reversible counters 3 and 9. two drivers 10 and I 1 full video, block 12 registration and monitor 13. The latter includes the keys 14 and 15, the television receiver 16, 17 image generator and inverter 13.

The device works as follows.

Before starting the study, the source information available in block 7 of the source code specification is recorded in the reversing counters 3 and 9 as a code signal providing the initial brightness level on the screen of the television receiver 16. In the reversing counters 3 and 9 the same code is recorded. This code signal shapers And) and II complete video signal is converted into analog signals that arrive at the and -th inputs of the keys 14 and 15.

The image generator 17 opens, in turn, the keys 14 and 15 and the auxiliary signal from the outputs of the formers 19 and II of the full video signal is fed to the input of the television receivers 16. The keys 14 and 15 have a common output and open alternately.

With the same code signals at the outputs of the reversible counters 3 and 9, respectively, with the same and taxable feeds at the outputs of the formers 10 and 1 I of the full video signal, a constant signal is received at the input of the television receiver 16. This constant signal provides an average background signal, at the level of which the visual system is examined and the contrast sensitivity of the eye is determined.

By changing the code signal in block 7 of setting the source code, you can change the level of the background signal.

After switching on the device using the button doctor switch I, the H 5 element is opened and the 4 pulse generator increases each code signal in one and accordingly reduces the code signal in another reversible counter, since the output of the AND element is connected to the summing input of one and the subtractive

the input of another reversible counter. When this occurs, a decrease in the magnitude of the analog signal at the output of one driver of the full signal and an increase at the output of the other driver of the full signal occurs. The same change occurs at the inputs and outputs of the keys 14 and 15. In this case, the input of the television receiver 16 receives the total signal of constant and variable magnitudes with a frequency specified by the generator 17 of the image. Moreover, the amplitude of the constant signal gradually decreases, while the amplitude of the alternating signal increases. On the screen of the television receiver 16 on a uniformly colored background of a given brightness, the bands are formed, the contrast of which increases linearly, starting from zero value 1, when the value of the variable signal is zero, they are not visible on the screen of television receiver 16). By increasing the amplitude of the variable amplitude, the image contrast increases. The rate of change of these amplitude values, respectively, and the magnitude of the contrast depends on the pulse frequency of the generator 4 pulses. By changing the frequency you can change the speed of the contrast in a wide range.

When the image reaches the threshold of image contrast, beginning with which the subject distinguishes between the stripes on the screen of the receiver 16, he presses the button on the switch

2 nannenta a, the process of changing the driving voltage at the outputs of reverse drivers 9 and 9 and, respectively, the values of analog signals at the outputs of the formers 19 and 11 of the full video signal.

the code signals at the outputs of the reversible counters k and 9, respectively, and the tax signals at the outputs of the formers 19 and 11 of the full video signal are proportional to the threshold value of the contrast.

Next, the code signals from the outputs of the reversible counters K and 9 are recorded by block 12 of the registration. If necessary, you can record the analog threshold value of the contrast from the outputs of the formers 19 and I 1 full signal.

To study the visual system, when the Contrast is reduced, on the screen of the television receiver 16 from the push button switch 1 of the dash unit 3 \ board, the element 'AND 6 K from the tenor 17 pulse is opened. Signals are fed to the inputs of the reversible counters 8 and 9. When

Volume 3 Reversing Other counters 8 and 9 in comparison with the contrast increase mode are changing modes. Reversible counter, which worked in the summation mode. in this case will work in subtraction mode, and vice versa.

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When the image reaches the contrast of the first value, starting from which the subject does not distinguish the strip on the screen of the television receiver 16, he pauses the process of changing the code value and, accordingly, analog signals by pressing the button on the patient's 2 switch 2. Code, respectively, and analog signals at the outputs of the reversible counters 8 and 9 and shapers And) and 11 full video signal determine ¹ threshold value of the contrast, which can be registered by the block 12 of the registration.

Thus, the device for studying the visual system provides an increase in the accuracy of determining the contrast sensitivity of the eye, as well as simplifies the process of research. With its help, the threshold values of the contrast sensitivity of vision at various frequencies of the bands on the television screen, which objectively and reliably characterize the state of the visual system, are determined promptly and without the participation of a doctor.

The device can be widely used in mass examinations of vision, diagnosis of eye disorders, professional selection of individuals in specialties with a special requirement for the visual system.

Claims (1)

Claim Device for the study of the visual system, which contains two push-button switches of the doctor and the patient, connected to the control unit, the monitor and the recording unit, characterized in that. In order to improve the accuracy of determining the contrast sensitivity of the eye, a pulse generator, two AND elements, a source code setting unit and two full video signal conditioners are entered into it, the first inputs of the AND elements are connected to the outputs of the control unit, and the second ones are connected to the output of the pulse generator, the output of the first element And connected to the summing input of the first and subtractive input of the second reversible counters, and the output of the second element And is connected to the subtractive input of the first and summing input of the second reversible counters, p At the same time, the inputs for setting the initial values of the latter are connected to the outputs of the source code setting unit and the control unit, in addition, the outputs of the reversible counters are connected to the registration units and through the corresponding full video signal drivers to the monitor.