JPH01129835A - Ultrasonic eye axial length meter - Google Patents

Abstract

PURPOSE:To allow an examiner to observe the change state of a reflection signal simultaneously with the execution of operation for bringing an ultrasonic probe into contact with the cornea of an eye to be examined, by providing a display means to an ultrasonic probe and displaying the state of an ultrasonic reflection signal on said display means. CONSTITUTION:When an ultrasonic probe 1 is brought into contact with the cornea E1 of an eye E to be examined to perform predetermined alignment operation, the signal waveform of the receiving signal S1 obtained by an ultrasonic transmitting- receiving circuit 11 usually becomes the intensity distribution of ultrasonic echos successively arranged in the order of the cornea E1, the front surface E2 of a lens, the rear surface E3 of the lens and the retina E4 in a time series manner. Herein, when the timing on the time series of the preliminarily extracted waveform is given by a waveform selection switch 7, the voltage level held by a sample holding circuit 14 can be set to the repeated voltage data of the reflection waveform of an arbitrary interface. By the voltage data as mentioned above, the display of a probe display device 2 lighting through a display driving circuit 16 becomes the level display of a real time relating to the arbitrary waveform of the receiving signal 51 quantized corresponding to the number of constitutional display segments.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultrasonic axial length needle for measuring the axial length of an eye to be examined by bringing an ultrasonic probe into contact with the cornea of the eye to be examined.

[Prior Art] Conventionally, as described in Japanese Patent Laid-Open No. 59-95031, an ultrasonic axial length meter consists of an ultrasonic probe section that contacts the cornea of the eye to be examined, and a main body section that processes signals. It is connected by a cable, and the examiner is configured to check the output of the display on the main body panel in order to read the level of the reflected signal during measurement.

[Problems to be Solved by the Invention] However, in the conventional example, since a display means for displaying the waveform of the reflected signal is provided in the main body, it is difficult to actually make measurements by bringing the ultrasound probe into contact with the cornea of the eye to be examined. When implementing this, there are the following problems.

(1) While operating the probe so that it makes good contact with the cornea of the eye to be examined, the examiner's line of sight is focused on the probe, making it impossible to observe the waveform of the reflected signal.

(2) If the line of sight is shifted onto the display means of the main body in order to check the waveform of the reflected signal, accurate probe operation will be hindered.

(3) Just by checking the frozen waveform at the time the measurement is completed, it is not possible to determine whether the measurement is being performed with the best reflected waveform.

[Object of the Invention] The object of the present invention is to provide an ultrasonic eye with good operability, which allows the examiner to observe changes in reflected signals at the same time as the operation of bringing an ultrasound probe into contact with the cornea of the eye to be examined. Our goal is to provide a quality measurement.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is to provide a specific axial long needle for measuring the axial length by bringing an ultrasound probe into contact with the cornea of the eye to be examined, in which a display means is provided on the ultrasound probe. The ultrasonic ophthalmoscope is characterized in that the state of the ultrasonic reflected signal is displayed on the display means.

[Embodiments of the invention] The present invention will be explained in detail based on illustrated embodiments.

In FIG. 1, E is the eye to be examined, and the ultrasound probe 1 can be brought into contact with the cornea El. A probe display 2 is attached to the side surface of the ultrasonic probe 1, and the ultrasonic probe 1 is further connected to a measuring instrument main body 4 via a cable 3. The measuring instrument main body 4 is provided with a monitor 5 for displaying the waveform of the ultrasound reflected signal, a printer 6 for printing the calculation results, a waveform selection switch 7, and a data display 8 for displaying the measured value of the axial length. .

FIG. 2 shows a block circuit diagram of the signal processing system, in which the ultrasonic probe 1 is connected to the ultrasonic transceiver circuit 11, and the output of the ultrasonic transceiver circuit 11 is transmitted to the ultrasonic signal processing circuit 12,
It is connected to a waveform selection circuit 13 and a sample hold circuit 14. The output of the sample hold circuit 14 is sent to the probe display 2 via the A/D conversion circuit 15 and the display drive circuit 16.
It is connected to the. Further, the output of the ultrasonic signal processing circuit 12 is connected to the data display 8, and the output of the waveform selection circuit 13 is connected to the sample hold circuit 14.

The ultrasonic transmitting/receiving circuit 11 transmits an ultrasonic driving signal to the ultrasonic probe l at a predetermined period, and receives the reflected signal of the ultrasonic echo generated by the interface of the test medium again via the ultrasonic probe l. It is composed of The reflected signal received by the ultrasonic probe 1 is amplified in a predetermined manner and then outputted from the ultrasonic transmitting/receiving circuit 11 as a receiving signal S1. The ultrasonic signal processing circuit 12 has a function of receiving the reception No. 4 Sl and executing a measurement calculation of the axial length, and displays the result on the data display 8 as axial length measurement data. On the other hand, the waveform selection circuit 13 is a time-limited circuit, which receives a trigger input of a timing signal synchronized with the ultrasonic drive signal from the ultrasonic transmitter/receiver circuit 11, and outputs a gate signal after an arbitrary delay time according to a command from the waveform selection switch 7. Output. Note that it is convenient to synthesize the timing of this gate signal as a waveform selection marker M on the monitor 5 by means not shown. It has the function of holding the voltage level of No. 4 S1. A/D conversion circuit 1
5 generates digital data corresponding to the voltage level output from the sample and hold circuit 14, and the display drive circuit 16 receives this digital data and controls the light emission of the corresponding display segment of the probe display 2. .

In the above configuration, when the ultrasound probe 1 is brought into contact with the corner 11!2E1 of the eye E to be examined and a predetermined alignment operation is performed, the reception No. 4 S obtained by the ultrasound transmission/reception circuit 11 is
Generally, the signal waveform of No. 1 is as shown in FIG. 3, and the signal waveform is generally as shown in FIG. The shape shows the intensity distribution of ultrasound echoes arranged in time series in the order of retina E4. Here, if the time-series timing of the waveform extracted in advance is given by the waveform selection switch 7, the voltage level held by the sample-and-hold circuit 14 can be set as repetitive voltage information of the reflected waveform of an arbitrary interface. can.

The display on the probe display 2 that is turned on via the 1-display drive circuit 16 based on the voltage information obtained in this way is related to an arbitrary waveform of the reception signal 4 SL that is quantized according to the number of display segments that constitute it. Real-time level display. In this case, it is preferable that the probe indicator 2 on the side of the ultrasound probe 1 be arranged as shown in FIG.

FIG. 5 is a block circuit diagram of the signal processing system of the second embodiment. Here, to explain only the parts that are different from FIG. 2, the reception No. 4 Sl of the ultrasonic transmitter/receiver circuit 11 is connected to a binarization circuit 21 and a gate pulse generation circuit 22 in addition to the ultrasonic signal processing circuit 12. The output of the discrimination level generation circuit 23 is also connected to the binarization circuit 21, and the output of the binarization circuit 21 is connected to four gate circuits 24a to 24d. Further, the output of the gate pulse generation circuit 22 is also input to the gate circuits 24a to 24d,
The output of ~24d is input to the display drive circuit 25 together with the output from the ultrasonic signal processing circuit 12.
The output of is connected to the probe indicator 2.

The binarization circuit 21 performs a binarization comparison of the reception signal S1 with a predetermined discrimination level signal S2 from the discrimination level generation circuit 23, and outputs a reception binary signal i3. The gate pulse generation circuit 22 receives a trigger input of a timing signal synchronized with the ultrasonic drive signal from the ultrasonic transmitter/receiver circuit ti, and generates each gate pulse having the phase shown as PamPd in FIG. Here, the gate pulse Pa is a reflected signal of the cornea El,
The gate pulse pb is a reflected signal from the front surface E2 of the crystalline lens, the gate pulse Pc is a reflected signal from the posterior surface E3 of the crystalline lens, and the gate pulse Pd is a reflected signal from the net 11E4. Display drive circuit 2
5 controls the light emission of the corresponding display segment of the probe display 2 in accordance with the outputs from the gate circuits 24a to 24d.

With the above configuration, when the ultrasound probe 1 is brought into contact with the cornea El of the eye E to be examined and the predetermined 7 alignment operations are performed, 2
The received binary signal S3 generated from the digitization circuit 21 is the third
As shown in the figure, the cornea El, the anterior surface of the crystalline lens E2, the posterior surface of the crystalline lens E3, and the like of the eye E, respectively. This becomes a logical signal obtained by quantizing the ultrasonic reflection signal of the retina E4 into binary values for the discrimination level S2. At this time, the gate pulse generation circuit 22 performs a masking process for the reception binarization circuit 21 using the preset gate pulse PaNPd, and the output obtained by the gate pulse generation circuit 22 is transmitted to the display drive circuit 2.
5 to independently illuminate the corresponding display segments of the probe display 2. Here, gate pulse Pa
- Received binary signal S3 in the time period corresponding to each phase of Pd.
If is a logic rlJ, the corresponding display segment of the probe display 2 is lit, and if it is a logic "0", it is not lit. In this case, the probe indicator 2 is preferably arranged as shown in FIG.

In the block circuit diagram shown in FIG.
The ultrasonic signal processing circuit 12 may have a function of calculating the reliability of the axial length measurement value using the following method.
The time-series data of the ultrasonic reflection signal included in the receiver No. 4 S1 is repeatedly input at a predetermined period by the action of the ultrasonic transmitter/receiver circuit 11, and the measured value of the axial length written as a result of calculation is constant. It is possible to calculate multiple items within a time period of . Here, a calculation operation is performed to compare the amount of dispersion of each measurement value with a predetermined value for multiple axial length measurement values obtained within a predetermined time, and the results of this comparison calculation are used to determine the measurement reliability. It is output to the display drive circuit 25 as a signal S4.

In this case, the contents displayed on the probe display 2 when the ultrasound probe l is brought into contact with the cornea El of the eye E to be examined include, in addition to the level discrimination value of the ultrasound reflection signal for each reflective surface, Depending on the state of the measurement reliability signal S4, which is a logic signal, the reliability indicator 26 provided on the ultrasound probe 1 is turned on or off together with the probe indicator 2, as shown in FIG.

Note that even with the configuration in which the monitor 5 of the above-described embodiment is removed, the measurement of the axial length can be performed by checking the display on the probe display 2 and the reliability display 26.

[Effects of the Invention] As explained above, the ultrasonic axial length meter according to the present invention includes a display device on the side surface of the ultrasonic glove to display the state of the ultrasonic reflection signal for each reflective surface of the test area. This allows the examiner to focus his/her line of sight on the probe and observe the state of the ultrasound reflected signal while simultaneously performing the alignment operation of the ultrasound probe that brings the ultrasound probe into contact with the cornea. It is also possible to check the reliability of the length measurement value in real time, improving the operability and accuracy of ultrasonic axial length measurement.

[Brief explanation of the drawing]

The drawings show an embodiment of the ultrasonic axial length meter according to the present invention, and FIG. 1 is an overall configuration diagram of the device, FIG. 2 is a block circuit diagram of a signal processing system, FIG. 3 is a signal waveform diagram, and FIG. Figure, Figure 6,
FIG. 7 is a layout diagram of the probe display, and FIG. 5 is the signal processing block circuit structure of the second embodiment. , is a diagram. 1 is an ultrasonic probe, 2 is a probe display, 4 is a measuring instrument body, 7 is a waveform selection switch, 8 is a data display,
11 is an ultrasonic transmitting and receiving circuit; 12 is an ultrasonic signal processing circuit;
13 is a waveform selection circuit, 14 is a sample hold circuit, 1
5 is an A/D conversion circuit, 16 is a display drive circuit, 21 is a binarization circuit, 22 is a gate pulse generation circuit, 23 is a discrimination level generation circuit, 25 is a display drive circuit, and 26 is a reliability indicator. Patent applicant: Canon Co., Ltd. Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. In an axial length meter that measures the axial length of the eye by bringing an ultrasound probe into contact with the cornea of the eye to be examined, the ultrasound probe is provided with a display means, and the state of the ultrasound reflected signal is displayed. An ultrasonic axial length meter characterized by displaying on the means. 2. The present invention further comprises a selection means for selecting one reflected signal from a plurality of reflected signals from a part of the eye to be examined, and the display means is driven in accordance with the output level of the selection means. The ultrasonic axial length meter according to item 1. 3. Claim 1 further comprises a discrimination means for comparing each of a plurality of reflected signals from a part of the eye to be examined with a predetermined level, and the display means is driven by the output of the discrimination means. The ultrasonic axial length meter described. 4. When the apparatus has reliability calculation means for comparing the calculation results of the axial length of each part of the eye to be examined, and the output of the reliability calculation means is within a certain value over a predetermined period of time. 2. The ultrasonic axial length meter according to claim 1, wherein said display means is driven.