SU1284519A1 - Apparatus for ultrasonic examination of the eye - Google Patents

Abstract

The invention relates to ultrasound examination of the eye in ophthalmology when measuring the size of the eye and its structures, and reduces the study time. The device contains an ultrasonic probe 1, transmitting 2 and receiving 3 blocks, meters 4, 5 and 6, automatic control unit 7, recorder 8, displacement sensor 9, two-coordinate

Description

WITH

with:

Yu

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four

O1

FIG. one

12, test object 10. Probe 1 is equipped with a convex-concave contact lens and a plane-convex lens, which contributes to the acoustic matching of the probe 1 with the eye, allows measurements outside the dead zone of the piezoelectric element and provides normal viewing conditions through the optically transparent medium of the probe 1. The probe is gently brought from the kbnjbro table 12 to the eye being examined (before the contact lens touches the cornea of the eye. When measured, the patient looks through the optically transparent probe 1 at the figure 10 illuminating on the test object. Ultra ƃ pulse propagates in the eye pr 1

The invention relates to medical technology, namely, devices for ultrasound examination of the eye, and can be used in medical practice in ophthalmology for ultrasound measuring the size of the eye and its structures.

The purpose and: acquisitions is to reduce the time of research.

FIG. 1 shows a functional diagram of the device} in FIG. 2, an electrical circuit of the timer; in fig. 3 shows the design of the ultrasound probe in FIG. 4 - diagrams of electrical voltages.

The device dp of ultrasound of the eye contains an ultrasound probe 1 with a water delay, a transmitting device 2 and a receiving 3 units connected to the ultrasound probe 1, the first 4, the second 5 and the third 6 meters with digital indication, the automatic control unit 7, the input of which is connected to the receiving unit 3, the first output of the automatic control unit 7 is connected to the transmitting unit 2 and to the first inputs of the first 4, second 5 and third 6 meters, the second and third outputs are connected respectively to the second and third inputs of the first 4, the second 5 and third 6 meters, the fourth, fifth and sixth outputs are connected to the fourth inputs of the first 4, second 5

linearly with a constant CKOpfHITWO, reflected from structural inhomogeneities: cornea, anterior and posterior borders of the lens and retina. The reflected pulses are converted by the measuring circuit of the device. A measurement of three sizes in the eye is carried out. The automatic control unit 7 distributes the echo signals coming from the front and rear borders of the lens and retina to the 4, 5 and 6 gauges. The introduction of new elements and the formation of new connections between the elements of the device shortens the test time 4 sludge.

and the third 6 meters, the recorder 8 of the first, second, third and fourth inputs of which are connected respectively to the displacement sensor 9 and the output of each measure 4-6.

The test object 10 and the displacement sensor 9 and their actuator 11 are mounted with an ultrasonic probe 1 on a two-coordinate table 12, and the test object 10 is mounted along the same axis as the ultrasonic probe 1 with the possibility of moving along this axis.

The automatic control unit 7 is designed to automatically distribute the received echoes that come from the front and back surfaces of the lens and from the retina of the eye to the corresponding meters 4-6 as a result of the launch of the transmitting unit 2.

The automatic control unit 7 is made in the form of a pulse generator 13 connected in series, a splitter 14, a time delay unit 15, a first RS flip-flop 16, a first comparator 17 with gating and a timer 18, a second 19, a third 20 and a fourth 21 RS-flip-flops and the second 22, third 23 and fourth 24 gates with comparators, the outputs of the first 17, second 22, third 23 and fourth 24 comparators with gating are connected to the R inputs of the first

-i

16, second 19, third 20 and fourth 21 triggers, the output of the pulse generator 13 is additionally connected to the first input of the timer 18.

The input of unit 7, connected to the receiving unit 3, is the combined first inputs of the comparators 17 and 22-24 with. gating. First output of the divider 14 automatic control unit 7 is also connected to the transmitting unit 2.

The 13 pulse generator with quartz frequency stabilization of 39 MHz is made according to a known scheme. The frequency of the pulse generator 13 is chosen based on the required measurement accuracy of 0.02 mm, since the pulse generator 13 amplifies the reference frequency (quantization frequency) for all three meters 4-6. In one pulse period of the generator 13 and the ultrasonic wave, the ultrasonic wave should propagate 0.02 mm based on the required measurement accuracy. With a known average speed of propagation of ultrasonic waves in the eye, equal to –1560 m / s, taking into account that during a surge pattern, the ultrasonic wave travels double distance, it is obtained that the period T of the pulse of the generator 13 is equal to:

BUT

t 2 2,564.10 s,

and the frequency f - - 39 MHz.

A divider 14 by 13000 is intended for dividing pulses with a frequency of 39 MHz to a frequency of 3 kHz and is made according to a known scheme on counters.

The time delay unit 15 is designed for a delay of 10 µs for the passage of pulses from divider 14- to the first trigger 16 and is performed on a single-oscillator with a logical element at the input.

Dual-input analog comparators 17 and 22-24-with gating are designed to generate pulses on the leading edge of the echo signals and can be performed using any known scheme of a two-input analog comparator with gating, designed to work with pulse signals.

The second inputs (gating) of the comparators 17 and 22-24 are connected to the outputs of the RS flip-flops 16 and 19-21 of the RS

AT

25

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responsibly. The level of operation of the comparators 17 and 22-24 is selected by setting the reference voltage and, at the third input of each — from the comparators — such that they are triggered by a signal equal to half the maximum output amplitude of the receiving unit 3.

The timer 18 is designed to generate pulses at certain time intervals from the moment the trigger igotulse is fed to it from the first comparator 17 and is completed according to a known scheme, for example (Fig. 2) as appropriately connected according to the scheme of the fifth trigger 25, first element 2I- NOT 26, three counters 27-29 and second 30, third 31 and fourth 32 elements 2I-NOT.

0 Input S of the second RS flip-flop 25, timer 18 is connected to the first comparator 17, the input of the first element 2I-NO 26 - to the generator of 13 pulses, and the outputs cf of the second 30, third 31 and fourth 32 elements 2I-NOT timer 18 podyhyuchen respectively, to the S inputs of the second 19, third 20, and fourth 21 triggers.

Ultrasonic probe 1 is designed to emit ultrasonic pulses and receive reflected signals in the pauses between the moment of measurement. Ultrasonic probe-1 (Fig. 3) consists of a housing 33, in which

35 an annular piezoelectric element 34 is glued with a matching, and a protective layer 35 and a layer of fflphere 36 applied to it. A conical nozzle 37 is attached to the body 33 with

40 end contact lens 38. In the housing 33 from the side of the damping layer

36 glued flat convex lens 39 with a flat surface in the direction of the conical nozzle 37. With a break of -5, the force of the lens 39 is calculated from the distance between the contact lens 38 and the lens 39. The nozzle

37 Filled with degassed water.

The contact lens 38 promotes good acoustic matching of the ultrasound probe 1 with the eye and is also the focusing element for the ultrasound beam.

The proposed design of the ultrasound probe 1 allows measurements outside the dead zone of the annular piezoelectric element 34, and also provides normal conditions

0

five

VIA for vision through the cancer of the probe. Transmitting unit 2

optically designed

for pulsed excitation of the piezoelectric ring 34 of the ultrasonic probe 1. The transmitting unit can be expanded in a known manner, for example, as in an ultrasonic device.

The receiving unit 3 is designed to amplify and detect the signals received by probe 1 and can be carried out according to a known scheme, for example, as in an ultrasonic device.

The first 4, the second 5 and the third 6 gauges with 1SCHFRU display are designed to measure the time interval between two signals reflected from the structures of the eye, convert it to distance and represent the results in digital form. The first 4, the second 5 and the third 6 gauges are identical in accordance with the well-known scheme.

The meters 4-6 with digital indication are calibrated so that they do not fix the eigenvalue of the measured time interval, but the proportional distance between the two intraocular structures.

Gauges 4-6 with digital display have twelve-digit digital-analog converters, the outputs of which are connected to the corresponding inputs of the recorder 8. The purpose of the recorder 8 is to register on paper the change in the measured dimensions during the accommodation of the eye when the test object 10 moves and object 10, the position signal of which is taken from displacement sensor 9, since the operator is not able to track three simultaneously changing readings of three gauges 4-6 with a digital indication. A self-recording high-speed instrument was used as the recorder 8.

The two-coordinate table 12 serves to smoothly bring the ultrasound probe 1, the test object 10, the displacement sensor 9 and the linear mechanical actuator 11 to the eye and the ultrasound probe 1 installed on it. The device uses a two-coordinate table from a slit lamp.

The test object K) s.nuzhngl, 4 chk (.: Ltsii, is on it in the process of examining the gaze of the patient and installed on a two-coordinate table 12 on the same axis with the ultrasonic probe 1 at a distance of 15 from it -20 cm, in such a way that it can smoothly move along this axis with the help of a linear mechanical displacement drive 11, a seven-segment digital indicator is used as a test object.

The linear mechanical-drive actuator 11 serves as a dp of smooth movement of the test object, 10 along

the axes of the ultrasound probe 1 at the distance from the distance of 15-20 cm from it. As a linear mechanical displacement actuator, any known actuator can be used, in particular, a drive screw rotating from an electric motor.

The movement sensor 9 serves for an electrical signal proportional to the movement of the test object to the first input of the recorder 8. Any known sensor can be used as a movement sensor, for example in the form of a rheochord. The device works as follows.

Before starting the examination, the patient's head is fixed. This can be done with a fixing device for a slit lamp. The patient's head is fixed in frame, tight to the headrest. Two-coordinate table 12 with probe 1 and test object-. Volume 10 is retracted to the extreme leftmost position. On the test object 10, a digit is displayed.

When the device operates in the measurement mode of the three eye sizes, the ultrasound probe 1 is smoothly supplied by the operator using the two-coordinate table 12 to the eye being examined before touching the contact lens 38 mounted on the end of the ultrasound probe 1 to the eye cornea. This provides an acoustic contact of the ultrasound probe 1 with the eye being examined. When measuring the eye, the patient looks through an optically transparent probe 1 at a 10 digit light on the test object. By installing the test object 10 along the axis of the ultrasound probe 1, an exact alignment of the optical axis of the eye with the axis of the ultrasound probe 1 and, corresponding to

Correspondingly, with the axis of the ultrasound beam, as well as rationing: the accommodation of the eye due to the installation of the test object 10 at a certain fixed distance from the ultrasound probe 1, which is a necessary condition for an accurate measurement.

When the device is turned on, the generator 13 of the pulses of the automatic control unit 7 is started, which absorbs the pulses of 39 MHz (Fig. 4.5), arriving at the divider 14, the timer 18 and the first 4, second 5 and third 6 meters. The divider 14 divides the pulses with a frequency of 39 mHz to a frequency of 3 kHz (figb, t,). The pulses from the output of the divider 14 trigger the transmitting unit 2, the time delay unit 15 and zero the meter 4-6. The transmitting unit 2 generates a powerful electrical impulse that excites ultrasonic and electrical oscillations in the annular piezoelectric element 34 of the ultrasonic probe 1.

The ultrasonic impulse propagates in the Conic nozzle 37. .. When acoustic contact of ultrasonic probe 1 with the eye being examined is impulse of ultrasonic vibrations

spreads in the eye of the eyeline - its 30 triggering from others who come

but with a practically constant speed of 1360 m / s, reflected from structural inhomogeneities located on its path, i.e. (cornea, anterior and posterior borders of the lens and retina).

The reflected ultrasonic pulses reach the ultrasound probe 1, are converted by it into pulses of electrical oscillations and arrive at the input of the receiving unit 3. In the latter, amplification and detection of received echo signals occurs. From the output of the receiving unit 3, echo signals (Fig. 4) are fed to the first inputs of the first 17, second 22, third 23 and fourth 24 comparators.

Simultaneously with the transmitting unit 2, a time delay unit 15 is started, which delays the pulse from 10 by the ISS from the splitter 14 to the RS flip-flop 16 (Fig. 42, C2). The first RS flip-flop 16 turns on after the 10th ISS and brings a signal to the input the first comparator 17 (Fig. 43, tj).

Thus, the first comparator 17 is turned on 10 μs after the excitation of the ultrasound pulse.

by the transmitting unit 2. This delay by 10 MKS eliminates the false positives of the first comparator 17 from the powerful electric pulse of the transmitting unit 2. The first comparator 17 is triggered by the first corneal echo (Fig. 4f, t), and the second is 22, the third 23 and the fourth 24 are comparators , at this point in time are turned off. The pulse from the output of the first comparator 17 (Fig. 4e, t) pos0

stupid for the first 4, second 5 and third 6 meters with digital indication. After arriving at the second inputs 5 of the 4-6 pulse meters from the output of the first comparator 17, they turn on and start counting the pulses with a frequency of 39 MHz, coming from the output of the generator 13.

The same pulse from the output of the first comparator 17 is fed to the R input of the first trigger 16 and to the S input of the first trigger 25 and timer 18. At the same time, the first trigger 16 switches to the zero state and turns off

The first comparator 17 (Fig. 49. t). Disconnect the first comparator 17

after the arrival of the first echo from the cornea, it avoids

five

later, echoes and thus eliminates false impulses for all three meters 4-6.

A pulse from the first comparator 17 turns on the fifth RS-trigger 25 of timer 18, which turns on the first element 2I-NOT 26. The included first element 2I-NO 26 pulses

A frequency of 39 MHz, coming from the output of the generator of 13 pulses, is fed to the series-connected first 27, second 28 and third 29 counters. After 100 pulses with a frequency of 39 MHz (t is 2.56 microseconds), the second element 2I – HE 30 is triggered and outputs a pulse to the S input of the second RS flip-flop 19 (FIG. 4g, t) j, which is turned on and sends a signal to the input gating the second comparator 22

(Fig. 4j, t). From now on, i.e. After 2.56 µs after the arrival of the echo from the cornea, a second comparator 22 is connected, which

triggered by the echo signal, which came to a depth of more than .2 mm, i.e. on the signal from the front surface of the lens. The second comparator 22 is triggered by an echo signal (Fig. 4a, t;) from the front surface of the lens and sends a pulse (Fig. 4i, t ,,) to the first meter 4 and to the F input of the second trigger 19, the Second trigger 19 turns off ( Fig. 4i, t) and disconnecting the second comparator 22, this eliminates the triggering of the comparator 22 from other echoes.

After the arrival of pulses from the second comparator 22 (Fig. 4i, t), the first meter 4 is turned off. During the time between the pulse from the first comparator 17 and from the second comparator 22, the first meter 4 receives a certain number of pulses with a frequency of 39 MHz from the generator 13, which is proportional to the time interval between the pulses from the first 17 and second 22 comparators.

In accordance with this calibration, the first gauge 4 with digital indication displays the result of measuring the distance between the cornea and the front surface of the lens, proportional to the time interval by echoes from these structures,

At the same time, the first 27, second 28, and third 29 counters of timer 18 continue to count pulses from the generator 13 pulses, cos. After 280 pulses with a frequency of 39 MHz (t 7.14 µs), the third element 2I – NE 31 is triggered and outputs a pulse to the S input of the third RS-trigger

Pa 20 (Fig. 4k, tg), which is turned on and supplies a signal to the gate input of the third comparator 23 (Fig. 4, tg). From now on, i.e. 7.14 µs after the arrival of the echo signal from the cornea of the eye, a third comparator 23 is connected, which is triggered by the echo signal coming from a depth of 5.5 mm, i.e. on the echo signal from the back surface of the lens (Fig. 4a, t), and at the same time impulses a pulse (Fig. 4m, t,) to the second meter 5 and to the K input of the third trigger 20. The third trigger 20 turns off (Fig. 4l, t) and turns off the third comparator 23, this eliminates the triggering of the latter from other echoes.

By the pulse from the third comparator 23 (Fig. 4m, t), the second meter 5 is turned off. During the time between the pulse from the first comparator 17 and the third comparator 23 on

five

0

five

0

five

the second meter 5 receives a certain number of pulses with a frequency of 39 MHz from generator 13, proportional to the time interval between pulses from the first 17 and third 23 comparators.

In accordance with the aforementioned calibration, the second gauge 5 with digital indication provides the result of measuring the distance between the cornea and the posterior surface of the lens, which is proportional to the time interval between the echoes from these structures.

At the same time, the first 27, second 28 and third 29 counters of timer 1B continue to count the pulses of the generator 13 pulses. After 900 pulses with a frequency of 39 MHz (t 23.07 µs), the fourth element 2И – НЕ 32 is triggered and returns a pulse to the R input of the second RS flip-flop 25, to the Nd inputs of the first 27, second 28 and third 29 counters and to S -Input of the fourth RS-flip-flop 21 (Fig. 4H, tg).

With this, the fifth RS flip-flop 25 is turned off and the first 27, second 28 and third 29 counters are zeroed. Timer 18 stops. The fourth RS-trIGG 21 is turned on (FIG. 4a, t) and connects the fourth comparator 24 through 23.07 µs after the arrival of the echo pulse from the cornea of the eye. The fourth comparator 24 switches on and echoes that come from a depth of over 18 mm, i.e. on the echo signals from the retina (figa, tg), and at the same time produces a pulse

40

H)

(Fig. 4I, t) on the third meter 6 and on the R-input of the fourth trigger 21 Quarter-trigger 21 (Fig. 4q,

turns off and off the fourth comparator 24. By impulse from

45 fourth comparator 24 (figp, tg) the third meter. 6 with digital indication is turned off. During the time between pulses from the first 17 and the fourth 24 comparators, a certain number of pulses with a frequency of 39 MHz, proportional to the time interval between the pulses from these comparators, hits it.

55

In accordance with the calibration indicated above, the third meter is 6 s digital; the indication results in the measurement of the distance between the cornea and the retina, proportional to the time interval between the echoes from these structures.

The time delays of the timer 18 t 2.56 ISS, t 7. 14 ISS and t 23.07 ISS were selected based on the average size of the eye and their deviations from the average value, taking into account the average ultrasound speed in the eye of 1560 m / s, so that The second 22, third 23 and fourth 24 comparators are connected only immediately before the arrival of the echo signals from the corresponding structures of the eye. The correctness of the choice of the indicated time delays is fully confirmed upon clinical approbation of the device.

Thus, a three-dimensional measurement in the eye is carried out on a single emitted ultrasound pulse. With the arrival of the next pulse from divider 14, the entire cycle of work is repeated.

When the device operates in the registration mode of the change in the process of eye size addition, three inputs (second, third and fourth) of the recorder 8 are connected to the outputs of each meter 4-6, and the first input is connected to the displacement sensor 9. By means of the linear mechanical movement actuator 11, the test object 10 is moved along the probe axis from the leftmost position to the rightmost position and back.

The measurement result of three gauges 4-6 with digital indication is converted by digital-analog converters installed at the outputs of three gauges 4-6 into an analog signal and recorded by the recorder 8 on paper. The current position of the test object 10 is recorded synchronously with the results of the three gauges 4-6 and the displacement sensor 9.

After completing the study, the ultrasound probe 1 and the test object 10 are gently removed from the patient's eye using the two-coordinate table 12. In the absence of acoustic contact of the ultrasound probe 1 with the eye, the ultrasonic pulse does not pass into the eye and only one echo from the end comes to the piezoplate of ultrasound probe 1 the conical nozzle, from which the riepuFiji operates, is a comparator 17, which starts timer 18. The second 22, third 23 and fourth 24 comparators are connected after the arrival of the echo signal and therefore do not work. The meters do not receive a pulse from the outputs of these comparators, and they indicate zeros.

The use of the proposed device for ultrasound examination of the eye will reduce the time of the study,

Ula Invention Form

An apparatus for ultrasound examination of the eye, comprising an ultrasound probe with a water delay, transmitting and receiving units, a meter with digital indication, characterized in that, in order to shorten the examination time, it is additionally equipped with a second and third meter, an automatic control unit and a recorder, The ultrasonic probe is equipped with a convex-concave contact lens and a flat-cone lens, the automatic control unit is designed as a sequentially connected pulse generator, sharing Eat frequency, time delay block, first RS trigger, first gated comparator, and timer, second to fourth RS flip-flops, and second to fourth comparators with gating, the outputs of the first to fourth comparators with gating are connected to the R-BXO of the first - the fourth flip-flop, the first - the third timer outputs are connected to the S-inputs of the second - fourth flip-flops, and their outputs are connected to the strobe inputs of the second - fourth comparators, while the output of the pulse generator is connected to the time input and, the automatic control unit outputs are connected to inputs of the transmitting unit, the first - third measuring devices and recorder connected to the outputs of the measuring; motors or movement sensor connected to the test object and its linear actuator mechanical movement.

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Claims (1)

The claims of approbation at 20 A device for ultrasonic examination of the eye, containing an ultrasonic probe with a water delay, transmitting and receiving units, a meter with digital indication, characterized in that, in order to reduce the time of examination, it is additionally equipped with a second and third meters, an automatic control unit and a recorder, and ultrasonic the probe is equipped with a convex-concave contact lens and a flat-convex lens, the automatic control unit is made in the form of a pulse generator connected in series, divide I have a frequency, a time delay block, the first RS-trigger, the first comparator with gating. and the timer, the second – fourth RS-triggers and the second – fourth comparators with gating, and the outputs of the first – fourth comparators with gating are connected to the R-outputs of the first – fourth flip-flops, the first and third outputs of the timer are connected to the S-inputs of the second and fourth triggers, and their outputs are connected to the gating inputs of the second fourth comparators, while the output of the pulse generator is connected to the input of the timer, the output automatic control unit 50 .The inputs are connected to the transmitting unit, the first and third measuring devices recorder connected to the outputs of gauges and displacement sensor connected to the test object and the drive pulse in piezoceramic plate 1 comes from the conical end 55 of its linear mechanical displacement. FIG. g II ¹ · I | I ί III I I I 11 I_______JLJ. t-gty tg it} • 4 — H ¹ K - RLMG Π I L M. ^g 'l if f . I I Πύρ 1 1Ί ΐ ----- '----- _r 123.07Mifc i L I / 1 I Etc h t I U__ 1 1 1 i1 ifTTf