JPH0624520B2 - Non-contact tonometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a fluid discharging means for discharging a fluid toward a cornea of an eye to be examined, and the fluid discharging means and the apex of the cornea. Alignment detecting means for detecting alignment and outputting an alignment signal, and determining whether alignment is completed by receiving the alignment signal of this alignment detecting means, and outputting an alignment completion signal when the alignment is completed And a control means for performing the fluid discharge of the fluid discharge means automatically based on the alignment completion signal.

(Prior Art) Conventionally, for example, Japanese Patent Publication No. 58-341 has been used for a non-contact tonometer.
The one disclosed in Japanese Patent Publication No. 28 is known. This conventional non-contact tonometer is a device as a fluid discharging means for discharging a fluid toward the cornea of an eye to be examined, and the device for detecting the completion of alignment between the axis of the device and the apex of the cornea. Irradiating infrared light to the cornea from the axial direction of the, the alignment detection means for causing the photoelectric conversion element to receive the infrared reflected light in the axial direction from the cornea and output an alignment signal from the photoelectric conversion element. And a control means for receiving the alignment signal of the alignment detecting means to determine whether or not the alignment is completed, and for outputting an alignment completion signal when the alignment is completed. The control means compares the received light amount signal value of the photoelectric conversion element with a set received light amount signal value corresponding to the received light amount of the photoelectric conversion element when the apex of the cornea coincides with the axis, and the deviation signal When the value is below a certain value, the alignment completion signal is output, and at the same time when the alignment between the axis of the device and the apex of the cornea is completed, an air pulse as a fluid automatically enters the cornea of the eye to be examined. The eye pressure of the eye to be inspected is measured based on the time from when the air pulse is blown to the cornea from the axial direction of the device until the cornea is flattened. ing.

(Problems to be Solved by the Invention) However, in the above-described conventional non-contact tonometer of the automatic fluid discharge type, when the alignment completion signal is continuously output, the air pulse is emitted based on the previous alignment completion signal. However, after the intraocular pressure measurement is completed, if the same eye accidentally re-establishes the alignment and a subsequent alignment completion signal is output, the air pulse is automatically emitted again.

In particular, this drawback is because the eye to be inspected that has a slight eye movement and children with low eye fixation tend to look aside and alignment is established.
Since the failure is repeated within a minute time, an air pulse is emitted each time, and moreover, the air pulse is not charged sufficiently in the cylinder of the air pulse emission system as the fluid ejection means, and the second and subsequent air pulses are ejected. Therefore, it is important in that it causes an error in the intraocular pressure measurement value.

The present invention is directed to overcoming such conventional drawbacks.

[Configuration of the Invention] In order to achieve the above object, the non-contact tonometer according to the present invention receives the alignment signal of the alignment detecting means for detecting the alignment between the fluid discharging means and the apex of the cornea, and the alignment is completed. Determine whether or not, and
Even if the alignment completion signal is continuously output to the control means that outputs the alignment completion signal when the alignment is completed, the fluid ejecting switch is not operated after the fluid is discharged based on the previous alignment completion signal. As a condition, a prohibition means for prohibiting the fluid discharge based on the subsequent alignment completion signal is provided.

(Operation) According to the non-contact tonometer according to the present invention, when the alignment signal is input from the alignment detection means to the control means, the control means receives the alignment signal and determines whether or not the alignment is completed. Then, when the alignment is completed, an alignment completion signal is output. When the alignment completion signal is continuously output, the prohibition means
The fluid discharging means is caused to discharge the fluid based on the alignment completion signal. After the fluid is discharged, the fluid is prohibited from being discharged based on the subsequent alignment completion signal on condition that the fluid discharge switch is not operated.

(Example) Below, the Example of the non-contact tonometer concerning this invention is described, referring drawings.

FIG. 1 is a block diagram showing a circuit configuration of essential parts of a non-contact tonometer according to the present invention. In this figure, 1 is a known fluid discharge means, 2 is a known alignment detection means, and 3 is a control means. Is. The fluid discharge means 1 has a function of discharging an air pulse as a fluid toward the cornea of an eye to be examined (not shown). The alignment detection means 2 has a function of detecting the alignment between the fluid discharge means 1 and the apex of the cornea and outputting the index detection signal Va as an alignment signal.
The alignment detecting means 2 has a photoelectric conversion element (not shown), and the index detection signal Va is output from the photoelectric conversion element. This photoelectric conversion element is disclosed in JP-B-58-3.
It corresponds to the one disclosed in Japanese Patent No. 4128 and the one described in Japanese Patent Application No. 60-59994 previously filed by the applicant. The control means 3 has a function of receiving the index detection signal Va, determining whether or not the alignment is completed, and outputting an alignment completion signal S ₁ when the alignment is completed.

The control means 3 includes a comparator 4 and a reference value generation circuit 5. The index detection signal Va is input to one terminal of the comparator 4, and the reference voltage Vc of the reference value generation circuit 5 is applied to the other terminal. This reference voltage Vc is for determining whether or not the alignment between the fluid discharging means 1 and the apex of the cornea is completed, and the comparator 4 uses the reference voltage Vc.
And the index detection signal Va are compared, and the index detection signal V
When the amplitude of a is larger than the reference voltage Vc, it is determined that the alignment is completed, its output terminal becomes H level, and the alignment completion signal S ₁ is at H level when the alignment is completed.

The control means 3 is provided with an auto mode selection switch 10 including a first AND circuit 11, a second AND circuit 12, an OR circuit 13, a flip-flop circuit 16, an inverter 17, and a toggle switch means.

The auto mode selection switch 10 is connected to the input terminal 11a of the first AND circuit 11. The output terminal of the inverter 17 is connected to the input terminal 11b. The output terminal of the first AND circuit 11 is one input terminal 12 of the second AND circuit 12.
connected to a. The output terminal of the comparison circuit 4 is connected to the other input terminal 12b. The output terminal of the second AND circuit 12 is the input terminal 13a of the fluid discharge means 1 and the OR circuit 13.
Connected to and respectively.

To the input terminal 13b of the OR circuit 13, a manual push button type air pulse firing switch 14, for example, is connected. An R / L switch 15 composed of a photoelectric switch having a configuration described later is connected to the input terminal 13b. The R / L switch 15 functions as a detection unit that detects whether the eye to be measured is the right eye or the left eye.

The output terminal 13d of the OR circuit 13 is connected to the flip-flop circuit 16, and the output terminal of the flip-prop circuit 16 is connected to the input terminal of the inverter 17.

The R / L switch 15 is a light emitting diode as shown in FIG.
The R / L switch 15 has a light receiving diode 152 and a light receiving diode 152, and is attached to the bottom of a moving table 30 that supports a tonometer main body (not shown). The movable table 30 can be moved back and forth, left and right on the pedestal 31 by the operation of a joystick (not shown). Here, the arrow X indicates the horizontal movement of the moving base 30, and the arrow Y indicates the rotating direction for moving the moving base 30 in the front-back direction. On the gantry 31, there is arranged a reflecting mirror 310 that reflects the light from the light emitting diode 151 toward the light receiving diode 152 when the movable table 30 is at the center position of its left and right movement.
Reference numeral 200 is a rack, 210 is a gear, 202 is a guide rod, 2
03 is a roller, and 204 and 205 are lenses.

With this configuration, the light 1 from the light emitting diode 151 is reflected toward the light receiving diode 152 and the reflected light is detected every time the moving table 30 that moves left and right of the moving table 30 passes through the center position of the gantry.

Next, the operation of the non-contact tonometer according to this embodiment will be described based on the dimming chart in FIG.

A. Air pulse automatic firing operation When a MAIN switch (not shown) is turned ON, the output of the inverter 17 becomes H level and is input to the first AND circuit 11. Next, the operator turns on the auto mode selection switch 10.
Then, the first AND circuit 11 becomes H level. When the auto mode selection switch 10 is turned on, both inputs of the first AND circuit 11 become H level, so that the output thereof becomes H level and the input terminal 12a of the second AND circuit 12 becomes H level. When the movable table 30 is moved to complete the alignment between the fluid discharge means 1 of the tonometer and the eye to be inspected, the alignment completion signal S ₁ is input to the comparator 4 at the input terminal 12a of the second AND circuit 12. Then, the output terminal of the second AND circuit 12 also becomes H level. As a result, the second AND circuit 12 outputs the command signal S ₂ for starting the fluid discharge to the fluid discharge means 1, the fluid discharge means 1 is activated, and the air pulse is emitted toward the eye to be examined. At the same time, the second AND circuit 12
Since the command signal S _{2 from} is input to the OR circuit 13, the output terminal of the OR circuit 13 becomes H level and the flip-flop circuit 16 becomes H level. The flip-flop circuit 16 maintains this H level state until the next input.

The H level output of the flip-flop circuit 16 is the inverter 17
Is converted to L level by the input terminal 11 of the first AND circuit 11
Entered in b. Therefore, the output of the first AND circuit 11 becomes L level, which causes the input terminal 12a of the second AND circuit 12 to become L level. Since this state is maintained while the flip-flop circuit 16 is at the H level, during this period, the alignment completion signal S ₁ based on the accidental alignment establishment due to, for example, the involuntary eye movement of the eye to be inspected is output to the second AND circuit.
Even if input to 12, the command signal S ₂ of the second AND circuit is L
The fluid discharge means 1 does not operate because the level is reached.

B. Re-measurement operation When the device user wants to measure the same eye to be measured again as before, the firing switch 14 is turned on. When this remeasurement command is input, the output of the OR circuit 13 becomes H level and is input to the flip-flop circuit 16. The input from the OR circuit 13 switches the flip-flop circuit 16 from the previous H level state to the L level state. Therefore, the input terminal of the first AND circuit 11 from the inverter 17 is input.
The input to 11a becomes H level. As a result, the second AN
The input terminal 12a of the D circuit 12 also becomes H level, and the fluid discharge means 1 is in a standby state. Then, when the alignment completion signal S ₁ is input, the command signal S ₂ of the second AND circuit 12 becomes H level, and the fluid discharge means 1 operates. At the same time, the command signal S ₂ from the second AND circuit 12 is ORed.
The output level of the flip-flop circuit 16 is switched from the L level to the H level by the output of the OR circuit 13 to the circuit 13. Since the flip-flop circuit 16 holds this state, the output of the inverter 17 becomes L level, the input terminal 11b of the first AND circuit 11 becomes L level, and
The output of the AND circuit 11 becomes L level. Therefore, the command signal S ₁ of the second AND circuit 12 also becomes L level regardless of the alignment completion signal S ₁ . As a result, the fluid discharge means 1 is held in the inoperative state.

That is, the 1AND circuit 11, the 2AND circuit 12, the flip-flop circuit 16, an inverter 17, also as an alignment completion signals S ₁ to have inherited is outputted, after fluid discharge in on the basis of the previous alignment completion signals S ₁ It functions as a prohibition means for prohibiting the fluid discharge based on the subsequent alignment completion signal S ₁ on condition that the fluid ejection switch 14 is not operated.

C. Switching the eye to be measured When the measurement of one eye, for example, the right eye is completed and the movable table 30 is moved to the left to move to the measurement of the left eye, the R / L switch 15 is turned on. When the R / L switch 15 is turned on, the output of the OR circuit 13 goes to H level, and the output of the flip-flop circuit 16 goes from H level to L level. Therefore, the inverter 17 changes from L level to H level,
The first AND circuit 11 becomes H level. Hereinafter, the above-mentioned “A.
It operates in the same way as the "air pulse automatic firing operation".

When the intraocular pressure measurement of one patient is completed and the intraocular pressure of a new patient is to be measured, the moving table 30 is moved again, and the apparatus main body is moved for measuring the right eye. R / L again by this movement
Since the switch 15 is turned on, the output of the OR circuit 13 goes to H level, the flip-flop circuit 16 goes from H level to L level, and the inverter 17 goes from L level to H level. Therefore, the output of the first AND circuit 11 becomes H level, and the air pulse is automatically emitted when the alignment completion signal S ₁ is input by the same operation as the above-described automatic air pulse emission operation. In other words, the first AND circuit 11, the second AND circuit 12, the flip-flop circuit 16, and the inverter 17 will output the fluid based on the previous alignment completion signal S ₁ even if the alignment completion signal S ₁ is output successively. It also functions as a prohibition unit that prohibits the fluid discharge based on the subsequent alignment completion signal S ₁ on condition that the movement of the detection unit that detects the movement of the tonometer body as the fluid discharge unit is not detected.

〔The invention's effect〕

As described above, according to the present invention, it is determined whether or not the alignment is completed by receiving the alignment signal of the alignment detecting unit that detects the alignment between the fluid discharge unit and the apex of the cornea, and Condition that the control means that outputs the alignment completion signal when the alignment is completed does not operate the fluid ejection switch after the fluid is discharged based on the previous alignment completion signal, even if the alignment completion signal is successively output. As a result, a prohibiting means for prohibiting the fluid discharge based on the subsequent alignment completion signal is provided, so that continuous ejection of the fluid pulse can be prevented. In addition, it is possible to prevent accidental and fluid discharge from occurring due to involuntary eye movement and improve the accuracy of intraocular pressure measurement.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a circuit configuration of a main part of a non-contact tonometer according to the present invention, FIG. 2 is a sectional view showing a configuration of an R / L switch according to the present invention, and FIG. 6 is a timing chart showing an example of the operation of the non-contact tonometer according to the present invention. 1 ... Fluid discharging means, 2 ... Alignment detecting means, 3 ... Control means, 10 ... Auto mode selection switch, 11, 12 ... First and second AND circuits 13 ... OR circuit, 14 ... Fluid ejection Switch, 15 ... R / L switch (detection means), 16 ... Flip-flop circuit, 17 ... Inverter.

Claims (1)

[Claims] 1. An alignment detecting means for detecting alignment between a fluid discharging means for discharging a fluid toward a cornea of an eye to be examined and an apex of the cornea and outputting an alignment signal, and an alignment signal from the alignment detecting means. And a control means for determining whether or not the alignment is completed and outputting an alignment completion signal when the alignment is completed, and automatically discharging the fluid of the fluid discharging means based on the alignment completion signal. In the non-contact tonometer to be executed on, the control means, even if the alignment completion signal is continuously output, the condition that the fluid ejection switch is not operated after the fluid is discharged based on the previous alignment completion signal. Is provided with a prohibition means for prohibiting fluid discharge based on a subsequent alignment completion signal. Non-contact tonometer that.